TY - JOUR TI - Wettability-based ultrasensitive detection of amphiphiles through directed concentration at disordered regions in self-assembled monolayers AU - Yao, Y. AU - Bennett, R.K.A. AU - Xu, Y. AU - Rather, A.M. AU - Li, S. AU - Cheung, T.C. AU - Bhanji, A. AU - Kreder, M.J. AU - Daniel, D. AU - Adera, S. AU - Aizenberg, J. AU - Wang, X. T2 - Proceedings of the National Academy of Sciences of the United States of America AB - Various forms of ecological monitoring and disease diagnosis rely upon the detection of amphiphiles, including lipids, lipopolysaccharides, and lipoproteins, at ultralow concentrations in small droplets. Although assays based on droplets' wettability provide promising options in some cases, their reliance on the measurements of surface and bulk properties of whole droplets (e.g., contact angles, surface tensions) makes it difficult to monitor trace amounts of these amphiphiles within small-volume samples. Here, we report a design principle in which self-assembled monolayer-functionalized microstructured surfaces coated with silicone oil create locally disordered regions within a droplet's contact lines to effectively concentrate amphiphiles within the areas that dominate the droplet static friction. Remarkably, such surfaces enable the ultrasensitive, naked-eye detection of amphiphiles through changes in the droplets' sliding angles, even when the concentration is four to five orders of magnitude below their critical micelle concentration. We develop a thermodynamic model to explain the partitioning of amphiphiles at the contact line by their cooperative association within the disordered, loosely packed regions of the self-assembled monolayer. Based on this local analyte concentrating effect, we showcase laboratory-on-a-chip surfaces with positionally dependent pinning forces capable of both detecting industrially and biologically relevant amphiphiles (e.g., bacterial endotoxins), as well as sorting aqueous droplets into discrete groups based on their amphiphile concentrations. Furthermore, we demonstrate that the sliding behavior of amphiphile-laden aqueous droplets provides insight into the amphiphile's effective length, thereby allowing these surfaces to discriminate between analytes with highly disparate molecular sizes. DA - 2022/// PY - 2022/// DO - 10.1073/pnas.2211042119 VL - 119 IS - 43 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85140271613&partnerID=MN8TOARS ER - TY - JOUR TI - Stimuli-Responsive Liquid-Crystal-Infused Porous Surfaces for Manipulation of Underwater Gas Bubble Transport and Adhesion AU - Rather, A.M. AU - Xu, Y. AU - Chang, Y. AU - Dupont, R.L. AU - Borbora, A. AU - Kara, U.I. AU - Fang, J.-C. AU - Mamtani, R. AU - Zhang, M. AU - Yao, Y. AU - Adera, S. AU - Bao, X. AU - Manna, U. AU - Wang, X. T2 - Advanced Materials AB - Biomimetic artificial surfaces that enable the manipulation of gas bubble mobility have been explored in a wide range of applications in nanomaterial synthesis, surface defouling, biomedical diagnostics, and therapeutics. Although many superhydrophobic surfaces and isotropic-lubricant-infused porous surfaces have been developed to manipulate gas bubbles, the simultaneous control over the adhesion and transport of gas bubbles underwater remains a challenge. Thermotropic liquid crystals (LCs), a class of structured fluids, provide an opportunity to tune the behavior of gas bubbles through LC mesophase transitions using a variety of external stimuli. Using this central idea, the design and synthesis of LC-infused porous surfaces (LCIPS) is reported and the effects of the LC mesophase on the transport and adhesion of gas bubbles on LCIPS immersed in water elucidated. LCIPS are demonstrated to be a promising class of surfaces with an unprecedented level of responsiveness and functionality, which enables the design of cyanobacteria-inspired object movement, smart catalysts, and bubble gating devices to sense and sort volatile organic compounds and control oxygen levels in biomimetic cell cultures. DA - 2022/// PY - 2022/// DO - 10.1002/adma.202110085 VL - 34 IS - 14 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85125092907&partnerID=MN8TOARS ER - TY - JOUR TI - Modularizable Liquid-Crystal-Based Open Surfaces Enable Programmable Chemical Transport and Feeding using Liquid Droplets AU - Xu, Y. AU - Chang, Y. AU - Yao, Y. AU - Zhang, M. AU - Dupont, R.L. AU - Rather, A.M. AU - Bao, X. AU - Wang, X. T2 - Advanced Materials AB - Droplet-based miniature reactors have attracted interest in both fundamental studies, for the unique reaction kinetics they enable, and applications in bio-diagnosis and material synthesis. However, the precise and automatic feeding of chemicals, important for the delicate reactions in these miniaturized chemical reactors, either requires complex, high-cost microfluidic devices or lacks the capability to maintain a pinning-free droplet movement. Here, the design and synthesis of a new class of liquid crystal (LC)-based open surfaces, which enable a controlled chemical release via a programmable LC phase transition without sacrificing the free transport of the droplets, are reported. It is demonstrated that their intrinsic slipperiness and self-healing properties enable a modularizable assembly of LC surfaces that can be loaded with different chemicals to achieve a wide range of chemical reactions carried out within the droplets, including sequential and parallel chemical reactions, crystal growth, and polymer synthesis. Finally, an LC-based chemical feeding device is developed that can automatically control the release of chemicals to direct the simultaneous differentiation of human induced pluripotent stem cells into endothelial progenitor cells and cardiomyocytes. Overall, these LC surfaces exhibit desirable levels of automation, responsiveness, and controllability for use in miniature droplet carriers and reactors. DA - 2022/// PY - 2022/// DO - 10.1002/adma.202108788 VL - 34 IS - 20 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85128187895&partnerID=MN8TOARS ER - TY - CHAP TI - Polymeric Membranes in Wastewater Treatment AU - Rather, A.M. AU - Xu, Y. AU - Dupont, R.L. AU - Wang, X. T2 - Nanoscale Engineering of Biomaterials: Properties and Applications PY - 2022/// DO - 10.1007/978-981-16-3667-7_17 SP - 487-515 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85130564956&partnerID=MN8TOARS ER - TY - JOUR TI - Exploration of the dislocation-electrochemistry relation in LiFePO4 cathode materials AU - Chen, Hongjiang AU - Kim, Sangwook AU - Huang, Hsiao-Ying Shadow T2 - Acta Materialia AB - Defects, such as dislocations, in electrode materials play a significant role in the performance of lithium-ion batteries. The dislocation-electrochemistry relation has only been observed experimentally and not been fully clarified. Computational studies on this mechanism were also very limited, especially the altered cyclic voltammetry behaviors and associated effective diffusivity. This work focuses on the influences of few characteristics of dislocations on the electrochemical performance of an anisotropic cathode material, lithium iron phosphate (LiFePO 4 ). Utilizing linear elastic mechanics and the superposition principle, we study stress and displacement fields of a LiFePO 4 particle containing different densities and orientations of dislocations. With the mechanical-electrochemical coupling effects expressed by the modified Butler-Volmer equation and using the finite different method, the cyclic voltammetry curves for different dislocation configurations in the particle are investigated. Our results show that introducing dislocations can shift and distort the cyclic voltammetry curves, especially at one specific dislocation orientation. It is also found that the Li-ion molar fraction-dependent partial molar volume is an important prerequisite of the distortion in cyclic voltammetry curves. Moreover, the altered cyclic voltammetry curves at different scanning rates indicate the improvements of electrical power, stored electrical energy, and the effective diffusivity of lithium. Our discrete dislocation model indicates that the capacity loss of LiFePO 4 nanoparticles can be alleviated by introducing tailored dislocations. This study assists the understanding of electrode materials with pre-existing dislocations and provides strategies of using defect engineering to improve the kinetic performance in lithium-ion batteries. DA - 2022/// PY - 2022/// DO - https://doi.org/10.1016/j.actamat.2022.118158 VL - 237 SP - 118158 UR - https://www.sciencedirect.com/science/article/pii/S1359645422005390 ER - TY - CONF TI - Virtual Hands-on Learning–The development of an online engineering design course with a virtual product inspection portal C2 - 2022/8/23/ C3 - American Society for Engineering Education DA - 2022/8/23/ UR - https://peer.asee.org/collections/2022-asee-annual-conference-exposition ER - TY - JOUR TI - Multiscale Electrochemomechanics Interaction and Degradation Analytics of Sn Electrodes for Sodium-Ion Batteries AU - Sarkar, Susmita AU - Malabet, Hernando Gonzalez AU - Flannagin, Megan AU - Alex, L’Antigua AU - Shevchenko, Pavel D. AU - Nelson, George AU - Mukherjee, Partha T2 - ACS Applied Materials & Interfaces AB - Sodium-ion batteries have emerged as a strong contender among the beyond lithium-ion chemistries due to elemental abundance and the low cost of sodium. Tin (Sn) is a promising alloying electrode with high capacity, redox reversibility, and earth abundance. Tin electrodes, however, undergo a series of intermediate reactions exhibiting multiple voltage plateaus upon sodiation/desodiation. Phase transformations related to incomplete sodiation in tin during cycling, in the presence of a frail solid electrolyte interphase layer, can quickly weaken the structural stability. The structural dynamics and reactivity of the electrode/electrolyte interface, being further dependent on the size and morphology of the active material particle in the presence of different electrolytes, dictate the electrode degradation and survivability during cycling. In this study, we paint a comprehensive picture of the underpinnings of the electrochemical and mechanics coupling and electrode/electrolyte interfacial interactions in alloying Sn electrodes. We elicit the fundamental role of electrode/electrolyte complexations in the Sn electrode structure-property-performance relationship based on multimodal analytics, including electrochemical, microscopy, and tomography analyses. DA - 2022/7/6/ PY - 2022/7/6/ DO - 10.1021/acsami.2c02772 UR - http://dx.doi.org/10.1021/acsami.2c02772 ER - TY - JOUR TI - Celebrating Women in Electrochemical Sciences and Engineering (WIESE) AU - Sarkar, Susmita AU - Chatterjee, Debanjali AU - Goswami, Navneet AU - Mukherjee, Partha T2 - ACS Energy Letters AB - ADVERTISEMENT RETURN TO ISSUEPREVEnergy FocusNEXTCelebrating Women in Electrochemical Sciences and Engineering (WIESE)Susmita SarkarSusmita SarkarSchool of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United StatesMore by Susmita Sarkar, Debanjali ChatterjeeDebanjali ChatterjeeSchool of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United StatesMore by Debanjali Chatterjee, Navneet GoswamiNavneet GoswamiSchool of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United StatesMore by Navneet Goswami, and Partha P. Mukherjee*Partha P. MukherjeeSchool of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States*Email: [email protected]More by Partha P. Mukherjeehttps://orcid.org/0000-0001-7900-7261Cite this: ACS Energy Lett. 2022, 7, 6, 2105–2112Publication Date (Web):May 27, 2022Publication History Received2 May 2022Accepted9 May 2022Published online27 May 2022Published inissue 10 June 2022https://doi.org/10.1021/acsenergylett.2c01026Copyright © Published 2022 by American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1937Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. 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Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (9 MB) Get e-AlertsSUBJECTS:Batteries,Electrical energy,Electrodes,Electrolytes,Students Get e-Alerts DA - 2022/6/10/ PY - 2022/6/10/ DO - 10.1021/acsenergylett.2c01026 UR - http://dx.doi.org/10.1021/acsenergylett.2c01026 ER - TY - JOUR TI - Effect of crystallite geometries on electrochemical performance of porous intercalation electrodes by multiscale operando investigation AU - Luo, Yuting AU - Bai, Yang AU - Mistry, Aashutosh AU - Zhang, Yuwei AU - Zhao, Dexin AU - Sarkar, Susmita AU - Handy, Joseph V. AU - Rezaei, Shahed AU - Chuang, Andrew Chihpin AU - Carrillo, Luis AU - Wiaderek, Kamila AU - Pharr, Matt AU - Xie, Kelvin AU - Mukherjee, Partha P. AU - Xu, Bai-Xiang AU - Banerjee, Sarbajit T2 - Nature Materials DA - 2022/2// PY - 2022/2// DO - 10.1038/s41563-021-01151-8 UR - https://doi.org/10.1038/s41563-021-01151-8 ER - TY - JOUR TI - A solution to the biophysical fractionation of extracellular vesicles: Acoustic Nanoscale Separation via Wave-pillar Excitation Resonance (ANSWER) AU - Zhang, Jinxin AU - Chen, Chuyi AU - Becker, Ryan AU - Rufo, Joseph AU - Yang, Shujie AU - Mai, John AU - Zhang, Peiran AU - Gu, Yuyang AU - Wang, Zeyu AU - Ma, Zhehan AU - Xia, Jianping AU - Hao, Nanjing AU - Tian, Zhenhua AU - Wong, David T. W. AU - Sadovsky, Yoel AU - Lee, Luke P. AU - Huang, Tony Jun T2 - Science Advances AB - High-precision isolation of small extracellular vesicles (sEVs) from biofluids is essential toward developing next-generation liquid biopsies and regenerative therapies. However, current methods of sEV separation require specialized equipment and time-consuming protocols and have difficulties producing highly pure subpopulations of sEVs. Here, we present Acoustic Nanoscale Separation via Wave-pillar Excitation Resonance (ANSWER), which allows single-step, rapid (<10 min), high-purity (>96% small exosomes, >80% exomeres) fractionation of sEV subpopulations from biofluids without the need for any sample preprocessing. Particles are iteratively deflected in a size-selective manner via an excitation resonance. This previously unidentified phenomenon generates patterns of virtual, tunable, pillar-like acoustic field in a fluid using surface acoustic waves. Highly precise sEV fractionation without the need for sample preprocessing or complex nanofabrication methods has been demonstrated using ANSWER, showing potential as a powerful tool that will enable more in-depth studies into the complexity, heterogeneity, and functionality of sEV subpopulations. DA - 2022/11/23/ PY - 2022/11/23/ DO - 10.1126/sciadv.ade0640 UR - https://doi.org/10.1126/sciadv.ade0640 ER - TY - CONF TI - Multi-fidelity Reduced-Dimensional Modeling for Shock-fin Interaction AU - Acharya, R. AU - Hartman, K. AU - Narayanaswamy, V. AB - Development of reduced-dimensional and reduced-order model simplifies a high-dimensional system by reducing the degrees of freedom, keeping only those that are important to model the nonlinear, multi-scale phenomena of interest. The research presented in this paper show a methodology for developing a reduced-dimensional and reduced-order model from a set of high-fidelity experimental data by a combination of unsupervised clustering methods and semi-supervised polynomial regression methods. The reduced-order model developed by this method is utilized to predict the pressure field for shock-boundary layer interaction phenomena occurring during the interaction of supersonic freestream flow over a cylinder with the double-fins mounted on the cylinder. Selections of certain regions of flow can be made to characterize how well the clustering algorithm reduces the order of the original data, while still capturing the most relevant physics. Statistical analysis of the training data enables uncertainty estimations of the reduced-order model developed in this work. Future work on this topic will include validation of the model as well as application for supersonic jet and fin interactions. C2 - 2022/// C3 - AIAA AVIATION 2022 Forum DA - 2022/// DO - 10.2514/6.2022-3479 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85135379771&partnerID=MN8TOARS ER - TY - CONF TI - Mach 4 Performance of a Hypersonic Streamtraced Inlet – Part 2: Computational Results AU - McCready, J.T. AU - Hoppe, C.A. AU - Johnson, E.C. AU - Edwards, J.R. AU - Narayanaswamy, V. AB - Reynolds-averaged Navier-Stokes simulations (RANS) at Mach 4 operation of a design Mach 5.5 inward-turning, streamtraced inlet tested in NCSU’s supersonic wind tunnel are presented. Computational predictions for an inlet geometry with squared-off leading edges indicate that the inlet unstarts, in accord with experimental observations. Comparisons between solutions obtained using an immersed-boundary (IB) method and those obtained on unstructured, body-fitted grids show small differences, but overall, the predictive capability of the IB approach is on par with conventional CFD methods. Simulations of a model with half-rounded leading edges show a started solution if a free-stream initialization is used but indicate that the inlet fails to start if the effects of the blowdown process in NCSU’s wind tunnel are modeled. Without boundary layer control, the experimental inlet model fails to start for all geometries tested. Comparisons with available PIV, planar laser scattering, and wall-pressure measurements indicate that the RANS approach based on Menter BSL and SST turbulence models adequately captures the structure of the streamtraced inlet flow fields under started and unstarted conditions. C2 - 2022/// C3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 DA - 2022/// DO - 10.2514/6.2022-0066 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85122577117&partnerID=MN8TOARS ER - TY - CONF TI - Mach 4 Performance of a Hypersonic Streamtraced Inlet Part 1: Experimental Investigations AU - Johnson, E. AU - Jenquin, C. AU - McCready, J. AU - Narayanaswamy, V. AU - Edwards, J. AB - Streamtraced inlets offer unparalleled efficiencies for scramjet engines, but limited experimental information is available on the sub-design performance of these inlets. In this study, the operation of a streamtraced half-Busemann inlet with a design point of Mach 5.5 and a contraction ratio of 3:1 is experimentally studied in a Mach 4.0 flow. Several non-intrusive flow measurement techniques are employed to provide a thorough understanding of the intricate flow field within these inlets at various operation conditions. These include the surface pressure and mean streakline patterns as well as off body velocity fields as well as semi-quantitative fields. Together, these datasets provided a unique understanding of the flow evolution and load distribution within the inlet at various operational phases that include tare condition without back pressuring as well as back pressure operation until unstart. The facility effects on the inlet operation is also explored where it was found that without boundary layer conditioning the wind tunnel starting shock could not be swallowed by the inlet. However, this "fails to start” operation enabled a unique lens to the flowfield in the unstarted inlet throat that was not possible with back pressure due to optical access restraints. C2 - 2022/// C3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 DA - 2022/// DO - 10.2514/6.2022-0065 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85122760827&partnerID=MN8TOARS ER - TY - CONF TI - Investigations of the Transition Between Conventional and Distributed Regime in Turbulent Jet Flames AU - Deboskey, R. AU - Kessler, D. AU - Johnson, R.F. AU - Bojko, B. AU - Sahoo, A. AU - Narayanaswamy, V. AU - Lyons, K.M. AB - Turbulent combustion of jet flames in a vitiated coflow was investigated across a range of jet Reynolds numbers. The studies revealed a transition from conventional autoignition combustion to a regime of moderate or intense low-oxygen dilution (MILD) combustion, which is commonly characterized by a nearly invisible flame. Typically, MILD combustion is achieved under conditions where the oxidizer has a high temperature and low oxygen content. Although substantial literature is available on conventional and MILD combustion, the boundaries of transition between the two regimes and the underlying driving mechanisms remain largely unknown. At North Carolina State University (NCSU), experimental investigations were performed in their Jet In Vitiated Co Flow Burner (JIVCFB) to explore the transition between conventional autoignition combustion and fully MILD flames. The Naval Research Laboratory (NRL) is performing accompanying simulations of these MILD experiments with their in-house JENRE® Multiphysics Framework. The experimental work primarily uses CH* chemiluminescence to image fully MILD methane flames in the NCSU JIVCFB. Due to the underlying complexity of MILD combustion, a series of counterflow flame cases were performed at various experimental conditions to better understand the link between kinetics, mixing, and strain at the transitional MILD conditions. These calculations were first performed in a series of premixed and non-premixed flames available in the literature to ensure the accuracy of the kinetics models. With the adequate evaluation of the accuracy of the models, they are employed to predict the species distribution of the NCSU’s MILD flame setting. The initial set of calculations provided in this work primarily focused on laminar strained flame calculations. Subsequently, preliminary modeling aimed to capture the fine fluid dynamic scales is presented to capture some of the fluid dynamic structures seen in experiments. C2 - 2022/// C3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 DA - 2022/// DO - 10.2514/6.2022-2089 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85123613832&partnerID=MN8TOARS ER - TY - CONF TI - Investigations of Shock Boundary Layer Interactions Over a Soft Material for Separated Control AU - Walz, J. AU - Narayanaswamy, V. AB - Integration of novel materials to high speed platforms holds the key to widening the vehicle operating envelope as well as enhancing their efficiency. Supersonic inlets can particularly benefit from new materials that can both help sustain a stable shock train during sub-design Mach number operation as well as not consume significant acreage that are seldom available in these sub-systems. This work explores the application of soft materials for the purpose of separation control within an inlet at sub-design operation. A rectangular channel that was open from the top (called half-inlet in this work) allowed for the boundary layers to develop along the walls and junctures, as is the case with planar inlets. A compression ramp placed at the aft end of the half-inlet generated a shock induced separation, which is a primary delimiter of the inlet performance. The half-inlet was placed in a Mach 2.5 inflow and two compression ramps, 20º and 24º, provided two different separation strengths for a parametric investigation. The material of choice was a polyurethane rubber that was embedded on the half-inlet floor over which the shock induced separation was introduced. Two different shore hardnesses (20A and 60A) were chosen for this exploration and the thickness of the rubber implant was fixed at 4 mm. The resulting separated flow was measured using a variety of data acquisition techniques that include surface streakline visualization, pressure-sensitive paint (PSP), and particle image velocimetry (PIV). Comparisons were made between the half-inlets without and with the rubber implant to quantify the separation response. The underlying mechanisms that cause the observed modifications to the separated flow is also discussed. C2 - 2022/// C3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 DA - 2022/// DO - 10.2514/6.2022-0605 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85122765351&partnerID=MN8TOARS ER - TY - CONF TI - Experimental Studies of Unstart Shock Dynamics within a Streamtraced Scramjet Inlet AU - Johnson, E. AU - Jenquin, C. AU - Narayanaswamy, V. AB - Streamtraced inlets offer unparalleled inlet efficiencies for hypersonic air breathing propulsion engines, but experimentally investigating these complex three-dimensional compression systems has proven to be a challenging task. Traditional pressure transducers can be difficult to mount to perfectly contoured geometries and simply cannot provide a holistic understanding of the three-dimensional flow field produced by these inlets. This effort address these concerns by implementing a sprayable dynamic pressure-sensitive paint to select interior regions of a streamtraced inlet. The use of this paint allows for a more complete understanding of the flow evolution within the scramjet inlet by producing time-accurate surface pressure fields at the painted areas. For this experimental study, this paint is used to examine the shock dynamics within a started inlet and during inlet unstart. Power spectral density analyses of the attached boundary layers within the isolator of the started inlet reveal energies that agree strongly with those measured within two-dimensional inlet/isolators, while cross-coherence studies of the unstarted inlet reveal a strong linear coupling between the separated inflow at the intake and the flow entrained within the isolator. C2 - 2022/// C3 - AIAA AVIATION 2022 Forum DA - 2022/// DO - 10.2514/6.2022-3478 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85135380742&partnerID=MN8TOARS ER - TY - JOUR TI - Fluid Structure Interactions Generated by an Oblique Shock Impinging on a Thin Elastic Panel AU - Narayanaswamy, V. AU - Varigonda, S.V. T2 - SSRN DA - 2022/// PY - 2022/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85145488659&partnerID=MN8TOARS ER - TY - CONF TI - Effects of Pressure Sensitive Paint on the Dynamics of Half-Inlet Shock Dynamics AU - Jenquin, C. AU - Johnson, E. AU - Narayanaswamy, V. AB - This study examined the pressure dynamics within the shock boundary layer interaction (SBLI) region of a steel half-isolator model. The steel model featured a 3D-printed microramp vortex generator (VG) and a compression ramp mounted on the steel half-isolator. The trailing edge of the VG was placed 50mm upstream of the compression ramp's leading edge. On top of this model, both thick and thin coats of homebrew, fast-response pressure sensitive paint (PSP) was applied. The fast-response PSP, imaged at 40kHz, allowed pressure fluctuations to be seen as the boundary layer interacted with the shock structure and with the high-momentum flow from the VG. Using a profilometry analysis, the height of the paint off the model was able to be quantified. The pressure data from the PSP was analyzed around the area of the SBLI, giving insight into how the thickness of the PSP affected the pressure dynamics in the SBLI region. The root mean square results indicate that the thickness of the paint serves to change the location of the shock impingement on the boundary layer. C2 - 2022/// C3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 DA - 2022/// DO - 10.2514/6.2022-0068 SP - 1-13 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85122673493&partnerID=MN8TOARS ER - TY - JOUR TI - Design and test a converging and de Laval nozzle using additive manufacturing AU - Chen, Mingtai AU - Baby, Ruksana AU - Dillard, Seth AU - Lee, Yi Tsung AU - Ekkad, Srinath T2 - Frontiers in Aerospace Engineering AB - The advent of additive manufacturing technology has facilitated the design and fabrication of parts and models in both academia and aerospace industry. Compressible flow in the nozzles is not a new research topic; however, the accuracy of the experimental results obtained from the nozzles using additive manufacturing has not been assessed comprehensively. Surface roughness and strength of 3D-printed nozzles are two major concerns when they are applied to compressible flows. In this paper, a converging and a de Laval nozzle fabricated by additive manufacturing using ABS filament are designed and tested. Surface roughness inside the converging nozzle is quantified using a nondestructive method. In general, the experimental results compare well with the analytical solutions from isentropic equations for the converging nozzle and the numerical simulations conducted in ANASYS Fluent for the de Laval nozzle. 3D-printed nozzles can be employed to quickly demonstrate and verify novel ideas and concepts in the pedagogy and research at large Reynolds numbers. DA - 2022/8/22/ PY - 2022/8/22/ DO - 10.3389/fpace.2022.951987 VL - 1 UR - http://dx.doi.org/10.3389/fpace.2022.951987 ER - TY - JOUR TI - A Laser-Coupled Dual Excitation Intravascular Ultrasound Transducer for Sonothrombolysis AU - Zhang, Bohua AU - Wu, Huaiyu AU - Jiang, Xiaoning T2 - 2022 IEEE NANOTECHNOLOGY MATERIALS AND DEVICES CONFERENCE, NMDC AB - In this paper, we first introduced a miniaturized dual excitation laser-coupled intravascular ultrasound transducer with both a piezoelectric stack and a laser ultrasound transducer, which can generate a low-frequency (425 kHz) and high-frequency (7.2 MHz) dual excitation waves for thrombolysis. The prototype transducer can generate peak-negative pressure (PNP) of about 3.0 MPa with 100 V pp input voltage and 8.5 MPa with 1mJ laser energy input, respectively. The in-vitro thrombolysis showed improved clot mass reduction (61.74 ± 3.15 %) and clot lysis speed (63.12 ± 4.35 mg/min) of dual-excitation ultrasound treatment compared to piezo or laser-generated ultrasound alone treatment. DA - 2022/// PY - 2022/// DO - 10.1109/NMDC46933.2022.10052561 SP - 37-40 SN - 2378-377X KW - laser ultrasound KW - carbon nanoparticles KW - ultrasound transducer KW - sonothrombolysis KW - catheter ultrasound ER - TY - MANSCPT TI - A Database for Reduced-Complexity Modeling of Fluid Flows AU - Towne, Aaron AU - Dawson, Scott T. M. AU - Brès, Guillaume A. AU - Lozano-Durán, Adrián AU - Saxton-Fox, Theresa AU - Parthasarathy, Aadhy AU - Jones, Anya R. AU - Biler, Hulya AU - Yeh, Chi-An AU - Patel, Het D. AU - Taira, Kunihiko DA - 2022/6// PY - 2022/6// ER - TY - CONF TI - Multiphysics FEA Simulation for Polymer Nanocomposite Laser Ultrasound Transducer AU - Liu, Sipan AU - Kim, Howuk AU - Chang, Wei-Yi AU - Huang, Wenbin AU - Jiang, Xiaoning AU - Ryu, Jong Eun T2 - IEEE C2 - 2022/// C3 - 2022 IEEE 22nd International Conference on Nanotechnology (NANO) DA - 2022/// SP - 249-252 ER - TY - JOUR TI - Designing non-textured, all-solid, slippery hydrophilic surfaces AU - Vahabi, Hamed AU - Vallabhuneni, Sravanthi AU - Hedayati, Mohammadhasan AU - Wang, Wei AU - Krapf, Diego AU - Kipper, Matt J. AU - Miljkovic, Nenad AU - Kota, Arun K. T2 - MATTER AB - Slippery surfaces are sought after due to their wide range of applications in self-cleaning, drag reduction, fouling-resistance, enhanced condensation, biomedical implants etc. Recently, non-textured, all-solid, slippery surfaces have gained significant attention because of their advantages over super-repellent surfaces and lubricant-infused surfaces. Currently, almost all non-textured, all-solid, slippery surfaces are hydrophobic. In this work, we elucidate the systematic design of non-textured, all-solid, slippery hydrophilic (SLIC) surfaces by covalently grafting polyethylene glycol (PEG) brushes to smooth substrates. Furthermore, we postulate a plateau in slipperiness above a critical grafting density, which occurs when the tethered brush size is equal to the inter-tether distance. Our SLIC surfaces demonstrate exceptional performance in condensation and fouling-resistance compared to non-slippery hydrophilic surfaces and slippery hydrophobic surfaces. Based on these results, SLIC surfaces constitute an emerging class of surfaces with the potential to benefit multiple technological landscapes ranging from thermofluidics to biofluidics. DA - 2022/12/7/ PY - 2022/12/7/ DO - 10.1016/j.matt.2022.09.024 VL - 5 IS - 12 SP - 4502-4512 SN - 2590-2385 ER - TY - JOUR TI - Template-free scalable fabrication of linearly periodic microstructures by controlling ribbing defects phenomenon during forward roll coating AU - Didarul Islam, Md AU - Perera, Himendra AU - Chockalingam, Sekkappan AU - Phillips, Matthew AU - Chen, Muh-Jang AU - Liu, Yuxuan AU - Khan, Saad AU - Zhu, Yong AU - Zikry, Mohammed AU - Eun Ryu, Jong T2 - Manufacturing Letters AB - Linear periodic microstructures are of significant importance in various applications, including drag-reduction, biofouling, self-cleaning, and superhydrophobicity. However, practical applications of such surfaces require mass manufacturing techniques, which are highly limited. This study demonstrated a simple template-free scalable manufacturing technique to fabricate linearly periodic microstructure by controlling the ribbing defects in forward roll coating. A viscoelastic polymer nanocomposite with tailored properties was synthesized and utilized as the coating material. The ribbing instabilities were controlled with process parameters that resulted in variable periodicity of the linearly aligned microstructures with a spacing of 114 – 700 µm. The microstructure arrangement also had a linear to random transition as the instabilities increased. The manufactured surface has a high Wenzel roughness factor that ranges from 1.6 to 3.6, which results in water contact angles of 128o to 150o. The linear microstructure films can have critical applications in the mass manufacturing of drag reduction surfaces. The high aspect-ratio microstructure films can also have applications in superhydrophobic, self-cleaning, anti-icing, and anti-biofouling surfaces. DA - 2022/9// PY - 2022/9// DO - 10.1016/j.mfglet.2022.08.001 VL - 33 SP - 153-160 J2 - Manufacturing Letters LA - en OP - SN - 2213-8463 UR - http://dx.doi.org/10.1016/j.mfglet.2022.08.001 DB - Crossref ER - TY - JOUR TI - Journal of Engineering Materials and Technology AU - Field, D. AU - Garmestani, H. AU - Khraishi, T. AU - Zikry, M. T2 - Journal of Engineering Materials and Technology, Transactions of the ASME DA - 2022/// PY - 2022/// VL - 144 IS - 1 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85127599106&partnerID=MN8TOARS ER - TY - JOUR TI - Next-Generation Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Source for Mass Spectrometry Imaging and High-Throughput Screening AU - Knizner, KT AU - Guymon, JP AU - Garrard, KP AU - Bouvree, G AU - Manni Jeffrey, Hauschild JP AU - others T2 - J Am Soc Mass Spectrom DA - 2022/// PY - 2022/// ER - TY - JOUR TI - Developing Transmission Mode for IR-MALDESI Mass Spectrometry Imaging AU - Joignant, Alena N AU - Bai, Hongxia AU - Guymon, Jacob P AU - Garrard, Kenneth P AU - Pankow, Mark AU - Muddiman, David C T2 - Rapid Communications in Mass Spectrometry DA - 2022/// PY - 2022/// SP - e9386 ER - TY - JOUR TI - Demonstration of a Towed Coaxial Turbine Subscale Prototype for Hydrokinetic Energy Harvesting in Skew AU - Agrawal, Saurabh AU - Williams, Vinson Oliver AU - Tong, Xinyang AU - Hassan, Mehedi AU - Muglia, Mike AU - Bryant, Matthew AU - Granlund, Kenneth AU - Ramaprabhu, Praveen AU - Mazzoleni, Andre P. T2 - 2022 OCEANS HAMPTON ROADS AB - The immense potential for ocean current energy harvesting is being actively explored by researchers, exhibiting the importance of the marine hydrokinetic industry. This paper presents a towed dual rotor coaxial turbine prototype built to demonstrate the ability of tethered, underwater, hydrokinetic devices to harvest energy from ocean currents. A sub-scale test article was developed to measure fluid power conversion and serve as a platform for operational feasibility in open-water testing. Tow testing of this article was done in the freshwaters of Lake Norman in North Carolina at three tow speeds: 1 m/s, 1.25 m/s and 1.5 m/s. Preliminary results demonstrate the ability to extract power, system robustness, waterproofing capabilities, and illuminates the nuances and non-linearities unique to the tethered coaxial turbine system. DA - 2022/// PY - 2022/// DO - 10.1109/OCEANS47191.2022.9977395 SP - SN - 0197-7385 KW - Ocean energy KW - Dual rotor KW - Coaxial turbine KW - Hydrokinetic energy KW - Blade-element momentum KW - Skew KW - Tethered energy devices ER - TY - JOUR TI - Characterization of the Steady-State Operating Conditions of Tethered Coaxial Turbines AU - Williams, Vinson Oliver AU - Bryant, Samuel AU - Agrawal, Saurabh AU - Mazzoleni, Andre P. AU - Granlund, Kenneth AU - Ramaprabhu, Praveen AU - Bryant, Matthew T2 - 2022 OCEANS HAMPTON ROADS AB - Tethered coaxial turbines (TCTs) may be a feasible configuration to extract hydrokinetic energy from the Gulf Stream’s flow. A TCT consists of two rotors attached to the halves of a rotary generator, which is moored to a mounting point via a tether. Flow causes the rotors to counter-rotate which induce power within the generator. The TCT’s steady-state operating domain and power extraction is determined by the intersection of the hydrodynamic operating domain of the rotors and electromechanic operating domain of the generator. As a result, the TCT’s operating point can be selected with an electrical load resistance, skew angle, and flow speed. Previous analytical methods for evaluating dual rotor devices have assumed ideal rotor, flow, and generator characteristics to simplify the quantification of power extraction. The proposed hydrodynamic analysis modifies traditional blade-element momentum theory (BEMT) to accept nonuniform inflow into the rotor, via a radially and azimuthally discretized BEMT method (RAD-BEMT). RAD-BEMT is leveraged alongside a momentum theory wake development factor to determine the response of the back rotor within the nonuniform wake of the front rotor. The back rotor response is determined by minimizing the difference in mass continuity and rotor torques. Our electromechanical analysis considers an AC generator, and the effects of voltage rectification, system resistance, and capacitance on the TCT’s power extraction capabilities. A case study was performed to demonstrate the ability of torque and mass continuity minimization to locate a hydrodynamic operating point, for axial and skew flow conditions. Additionally, power extraction capabilities, load resistance selection, and the qualitative effects of skew on the minimization domain are discussed. DA - 2022/// PY - 2022/// DO - 10.1109/OCEANS47191.2022.9977052 SP - SN - 0197-7385 KW - Coaxial turbine KW - hydrokinetic energy KW - blade-element momentum KW - skew KW - nonuniform inflow KW - tethered energy devices ER - TY - JOUR TI - Analytical wake model for coaxial dual-rotor turbines AU - Hassan, Mehedi AU - Bryant, Matthew AU - Mazzoleni, Andre AU - Ramaprabhu, Praveen AU - Granlund, Kenneth T2 - 2022 OCEANS HAMPTON ROADS AB - This work develops and validates a novel analytical wake model for coaxial dual-rotor turbines. With the diameters, and axial induction factors of the upstream and downstream rotors, and the freestream velocity, the proposed model estimates the wake velocity deficit in the near- and far-wake of the coaxial turbine. It is developed by utilizing the Bernoulli principle along the streamlines that pass through the near- and far-wake control volumes and the conservation laws for mass and momentum. This simple model can be used to calculate the velocity distribution in the wake using just one parameter. The wake prediction is contrasted with CFD results for various flow conditions to find good agreements between them. The novel wake model can be useful for solving the turbine farm layout optimization problem that involve dual-rotor configurations for the power generators. DA - 2022/// PY - 2022/// DO - 10.1109/OCEANS47191.2022.9977241 SP - SN - 0197-7385 ER - TY - JOUR TI - Increased Energy Conversion with a Horizontal Axis Turbine in Translation AU - Metoyer, Rodney AU - Bryant, Matthew AU - Granlundt, Kenneth AU - Mazzoleni, Andre T2 - 2022 OCEANS HAMPTON ROADS AB - When fixed to the ground by tower or stanchion, horizontal axis turbines convert hydrokinetic power into electric power by passively exploiting the difference in velocity between the ground and a flowing fluid. This method of converting the available hydrokinetic power is relatively simple, but the maximum amount of power that may be converted to another form by the turbine has a theoretical upper limit, called the Betz limit, which is about 59.25% of the hydrokinetic power in a stream tube of the freestream flow with a cross sectional area equal to the area of the turbine rotor plane. The work presented demonstrates that eschewing the stanchion and making the turbine to translate through the fluid enables conversion of more hydrokinetic power and, when operated in a cyclical mode, more energy over a cycle. It is demonstrated with momentum theory that the maximum energy that may be converted over a cycle is 1.5 times the Betz limit for an equivalent ground-fixed stationary turbine in the same low. Following the theoretical analysis, the concept is proven by simulation for a non-ideal turbine using an engineering design tool developed by the United States National Renewable Energy Laboratory. The results show that a realistic, non-ideal translating turbine can convert over twice as much power as an equivalent stationary turbine. Additionally, a notional tidal current application is presented where the bidirectionality of flow is exploited to achieve energy conversion of more than twice the theoretical limit of an ideal stationary turbine. DA - 2022/// PY - 2022/// DO - 10.1109/OCEANS47191.2022.9977131 SP - SN - 0197-7385 KW - marine hydrokinetic energy KW - translating turbine KW - momentum theory KW - renewable energy ER - TY - JOUR TI - Closed-Loop-Flight-Based Combined Geometric and Structural Wing Design Optimization Framework for a Marine Hydrokinetic Energy Kite AU - Beknalkar, Sumedh AU - Naik, Kartik AU - Vermillion, Chris AU - Mazzoleni, Andre T2 - 2022 OCEANS HAMPTON ROADS AB - A marine hydrokinetic (MHK) kite offers an economical solution to the challenges of size and investment costs posed by the existing class of energy converters used to harvest tidal and ocean current energy. MHK kite systems are complicated devices that harvest ocean current energy by flying a tethered kite perpendicular to the motion of the current flow. They possess strong coupling between closed-loop flight control, geometric design, and structural design and hence it is important to consider all three facets simultaneously while designing a MHK kite system. Our previous work addressed this problem of simultaneous optimization of plant and controller through a control-aware optimization framework that fuses a geometric optimization tool, a structural optimization tool, and a closed-loop flight efficiency map. While our previous work analyzed the effect of key wing geometric parameters (wingspan and aspect ratio) on the performance of MHK kite systems, the present work represents the next crucial step in the study of ocean energy-harvesting kite systems and expands the design space to include several other wing geometric parameters - airfoil design, wing taper, wing twist, and dihedral angle. The effect of these decision variables on the power-to-mass ratio is estimated through an optimization framework based on a sequential approach. First, using sensitivity analysis, the framework determines which design variables in the design space affect the peak mechanical power generated while flying a cross-current path. In the next step, the combined geometric and structural optimization tool derives optimal values of variables in the reduced design space that results in a minimum structural mass. The constraints in the optimization problem include a lower limit on the peak power and limits on the number and dimensions of I-beam spars and the thickness of the wing shell. With a wing structure that can sustain peak lifting loads equal to less than a fixed value, the rest of the design variables are optimized to achieve maximum time-averaged power using medium-fidelity closed-loop-flight-based simulations. The final results of the optimization framework include an optimized wing geometry and wing structure with a maximized power-to-mass ratio for an MHK kite. DA - 2022/// PY - 2022/// DO - 10.1109/OCEANS47191.2022.9977369 SP - SN - 0197-7385 KW - ocean current energy KW - marine hydrokinetic kite KW - combined geometric and structural optimization KW - sensitivity analysis KW - closed-loop-flight simulations KW - taper ratio KW - wing twist KW - dihedral angle ER - TY - JOUR TI - Aging rate of dielectric permittivity and loss for PMN-PT based single crystals manufactured by continuous-feeding Bridgman with alternating current poling AU - Wang, Zhuangkai AU - Yamashita, Yohachi AU - Luo, Cong AU - Sun, Yiqin AU - Karaki, Tomoaki AU - Fujii, Tadashi T2 - JOURNAL OF THE CERAMIC SOCIETY OF JAPAN AB - Aging rate (AR) of dielectric permittivity (ε33T/ε0) of ternary Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PIN–PMN–xPT, x = 26 and 30 mol %) and binary Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT, x = 30 mol %) single crystals (SCs) grown by the continuous-feeding Bridgman method (CF-BM) were investigated. The AR of dielectric permittivity was 0.6–2.0 %/decade, whereas that of dielectric loss of the SCs was 1–8 %/decade. Even though the SC growth methods were different, the AR of CF-BM PMN–30PT SCs were similar with that of conventional one-charge Bridgman method (OC-BM) SCs. In this work, the AR of the SCs possessing high ε33T/ε0 more than 8000 by alternating current poling (ACP) was 4 to 7 times larger than that of PZT ceramics. It is noted that SCs with higher ε33T/ε0 tend to exhibit higher AR. Given that the SCs were in an unstable state within 10 h after poling, the AR presented in this paper was calculated from 10 to 100 h after poling. We hope this work provides a new insight for evaluating the properties of the SCs and addresses the fact that SCs for piezoelectric devices should be properly selected by considering whether their AR could let them work normally during their entire lifetime. DA - 2022/9// PY - 2022/9// DO - 10.2109/jcersj2.22045 VL - 130 IS - 9 SP - 794-801 SN - 1348-6535 KW - Alternating current poling KW - Relaxor-PbTiO3 single crystal KW - Aging rate KW - Dielectric property KW - Dielectric loss ER - TY - JOUR TI - Fabrication of Bioinspired Micro/Nano-Textured Surfaces Through Scalable Roll Coating Manufacturing AU - Black, Benjamin AU - Chockalingam, Sekkappan AU - Islam, Md Didarul AU - Liu, Sipan AU - Perera, Himendra AU - Khan, Saad AU - Ryu, Jong Eun T2 - Journal of Micro and Nano-Manufacturing AB - Abstract Bio-inspired, micro/nanotextured surfaces have a variety of applications including superhydrophobicity, self-cleaning, anti-icing, antibiofouling, and drag reduction. In this paper, a template-free and scalable roll coating process is studied for fabrication of micro/nanoscale topographies surfaces. These micro/nanoscale structures are generated with viscoelastic polymer nanocomposites and derived by controlling ribbing instabilities in forward roll coating. The relationship between process conditions and surface topography is studied in terms of shear rate, capillary number, and surface roughness parameters (e.g., Wenzel factor and the density of peaks). For a given shear rate, the sample roughness increased with a higher capillary number until a threshold point. Similarly, for a given capillary number, the roughness increased up to a threshold range associated with shear rate. A peak density coefficient (PDC) model is proposed to relate capillary number and shear rate to surface roughness. The optimum range of the shear rate and the capillary number was found to be 40–60 s−1 and 4.5 × 105–6 × 105, respectively. This resulted in a maximum Wenzel roughness factor of 1.91, a peak density of 3.94 × 104 (1/mm2), and a water contact angle (WCA) of 128 deg. DA - 2022/6/1/ PY - 2022/6/1/ DO - 10.1115/1.4056732 VL - 10 IS - 2 SP - 021006 SN - 2166-0468 2166-0476 UR - http://dx.doi.org/10.1115/1.4056732 ER - TY - JOUR TI - Laser powder bed fusion additive manufacturing of oxide dispersion strengthened steel using gas atomized reaction synthesis powder AU - Horn, Timothy AU - Rock, Christopher AU - Kaoumi, Djamel AU - Anderson, Iver AU - White, Emma AU - Prost, Tim AU - Rieken, Joel AU - Saptarshi, Sourabh AU - Schoell, Ryan AU - DeJong, Matt AU - Timmins, Sarah AU - Forrester, Jennifer AU - Lapidus, Saul AU - Napolitano, Ralph AU - Zhang, Dalong AU - Darsell, Jens T2 - MATERIALS & DESIGN AB - Mechanically alloyed Fe-based alloys with oxide dispersion strengthening have largely dropped out of the marketplace due to high cost related to problems with complex and unreliable processing. Nevertheless, the desirable properties of oxide dispersion strengthened (ODS) steels have motivated research on alternate processing routes aimed at improving processing simplicity and reliability. Powders produced by gas atomization reaction synthesis (GARS) consist of stable Fe-Y intermetallic phases and a Cr surface oxide layer that acts as a chemical reservoir during solid-state processing and heat treatment to form a high density of nano-scale oxides. This research explores the use of Fe GARS powders, with 15 wt% Cr with micro-alloyed additions of 0.15 wt% Y and 0.10% Ti, in laser powder bed fusion (LPBF) additive manufacturing (AM), and evaluates the effectiveness of oxide dispersoid formation in the liquid melt pool. Additional oxygen was introduced by varying the LPBF chamber atmospheres using Ar, Ar + 1 wt% O, Ar + 5 wt% O, and air. Characterization of LPBF consolidated solids demonstrated the formation of a high density of nano-scale Y-Ti oxides in the build microstructures from the GARS precursor powders. DA - 2022/4// PY - 2022/4// DO - 10.1016/j.matdes.2022.110574 VL - 216 SP - SN - 1873-4197 ER - TY - JOUR TI - A vertex-centered finite volume method with interface sharpening technique for compressible two-phase flows AU - Li, Lingquan AU - Lohner, Rainald AU - Pandare, Aditya K. AU - Luo, Hong T2 - JOURNAL OF COMPUTATIONAL PHYSICS AB - A robust and efficient finite volume method with interface sharpening technique has been developed to solve the six-equation multi-fluid single-pressure model for compressible two-phase flows. The numerical method is implemented in a three-dimensional vertex-centered code. A least-squares reconstruction with Kuzmin's vertex-based (VB) limiter is implemented for the volume fraction and a set of primitive variables in the presented finite volume framework. In regions where two different fluid components are present within a cell, a sharpening technique based on THINC (Tangent of Hyperbola for Interface Capturing) is adopted to provide a sharp resolution for the transitioning interface. These reconstructed values are then used as the initial data for Riemann problems. The enhanced AUSM+ -up scheme is applied to both liquid and gas flows. The multi-stage Runge-Kutta method is used for time marching. A number of benchmark test cases are presented to assess the performance of the present method. These include: an air-water interface moving at a constant velocity, Ransom's faucet problem, air-water/water-air shock tube problems with high pressure ratios, a shock in air impacting a water column case, an underwater explosion case and an air bubble blast case. In all of these cases, the shock and rarefaction waves are captured accurately, especially with the THINC interface sharpening technique. • The single pressure six-equation model is implemented in a three-dimensional vertex-centered code. • The Tangent of Hyperbola interface sharpening technique is implemented. • A number of test cases are presented to show the accuracy of the developed numerical method. • The numerical results in this paper are in good comparison with the literature. DA - 2022/7/1/ PY - 2022/7/1/ DO - 10.1016/j.jcp.2022.111194 VL - 460 SP - SN - 1090-2716 KW - Six-equation model KW - Compressible two-phase flow KW - Multi-fluid KW - Interface sharpening KW - Vertex-centered ER - TY - JOUR TI - Genetic algorithm shape optimization to manipulate the nonlinear response of a clamped-clamped beam AU - Mollik, Tushar AU - Geng, Ying AU - Ul Shougat, Md Raf E. AU - Fitzgerald, Timothy AU - Perkins, Edmon T2 - HELIYON AB - Dynamical systems, which are described by differential equations, can have an enhanced response because of their nonlinearity. As one example, the Duffing oscillator can exhibit multiple stable vibratory states for some external forcing frequencies. Although discrete systems that are described by ordinary differential equations have helped to build fundamental groundwork, further efforts are needed in order to tailor nonlinearity into distributed parameter, continuous systems, which are described by partial differential equations. To modify the nonlinear response of continuous systems, topology optimization can be used to change the shape of the mechanical system. While topology optimization is well-developed for linear systems, less work has been pursued to optimize the nonlinear vibratory response of continuous systems. In this paper, a genetic algorithm implementation of shape optimization for continuous systems is described. The method is very general, with flexible objective functions and very few assumptions; it is applicable to any continuous system. As a case study, a clamped-clamped beam is optimized to have a more nonlinear or less nonlinear vibratory response. This genetic algorithm implementation of shape optimization could provide a tool to improve the performance of many continuous structures, including MEMS sensors, actuators, and macroscale civil structures. DA - 2022/11// PY - 2022/11// DO - 10.1016/j.heliyon.2022.e11833 VL - 8 IS - 11 SP - SN - 2405-8440 KW - Shape optimization KW - Nonlinear oscillators KW - Beams KW - Duffing oscillator ER - TY - JOUR TI - A Mori-Tanaka method based theoretical approximation for functionally graded thick wall tube under combined thermal and mechanical loads AU - Xin, Libiao AU - Xu, Jifeng AU - Li, Zhiqiang AU - Li, Yanbin T2 - JOURNAL OF THERMAL STRESSES AB - In this work, a FGM thick wall tube under both thermal and mechanical loadings is studied by referring to the Mori-Tanaka method. The studied FGM tube is assumed to be made of two distinct linear elastically deformable materials equipped with unique volume fractions. Specially, its material parameters are firstly evaluated in the scheme of the Mori-Tanaka method which can more accurately depict the effective material properties of FGMs composites. Later, we derive the ordinary differential equation (ODE) of the displacement along radial direction, based on which we determine the approximate analytical results of displacement and later derive explicit forms of stress components along all the radial, axial and circumferential directions. After comparison, we found that the derived analytical results agree well with that obtained through numerical method. Moreover, for the same researching problem we found the Mori-Tanaka method could outperform the Voigt method. Further, the results are valid for materials with different Poisson’s ratios rather than constant Poisson’s ratios usually used in the existing references. Finally, parametric studies are also conducted by exploring the variations of the displacement and stress components affected by different volume fractions and distinct thermal conductivities and expansion coefficients. DA - 2022/12/20/ PY - 2022/12/20/ DO - 10.1080/01495739.2022.2155743 SP - SN - 1521-074X KW - Functionally graded material KW - the Mori-Tanaka method KW - theoretical approximation KW - thermoelastic behavior KW - thick wall tube ER - TY - JOUR TI - Drag-Mitigating Dynamic Flight Path Design for an Ultra-Long Tether Underwater Kite AU - Abney, Andrew AU - Vermillion, Chris T2 - IFAC PAPERSONLINE AB - This paper presents a computational study of an underwater kite operating in an ultra-long tether (ULT) application. Leveraging a dynamic model established in literature, we study the relationship between path shape and tether drag at varying tether lengths in order to develop meaningful insights as to the operation of systems that require ultra-long tethers in order to reach available flow resources. The results are compared to fundamental tether drag relationships developed in the airborne wind energy field, including the multi-airborne wind energy system (MAWES) proposed by Leuthold et al. (2017, 2018). It will be shown that by careful selection of path shape, these fundamental relationships break down in deep-water marine environments, and that high performance rivaling that of the MAWES system can be achieved, without the extra required mechanical complexity. DA - 2022/// PY - 2022/// DO - 10.1016/j.ifacol.2022.11.176 VL - 55 IS - 37 SP - 151-157 SN - 2405-8963 ER - TY - JOUR TI - Eco-friendly screen printing of silver nanowires for flexible and stretchable electronics AU - Shukla, Darpan AU - Liu, Yuxuan AU - Zhu, Yong T2 - NANOSCALE AB - This paper reports an eco-friendly method for screen printing of silver nanowires on a diverse range of substrates with high resolution and high electric conductivity. A low annealing temperature makes the method compatible with plastic substrates. DA - 2022/12/20/ PY - 2022/12/20/ DO - 10.1039/d2nr05840e SP - SN - 2040-3372 ER - TY - JOUR TI - Integration of Forward-viewing and Side-viewing Ultrasound Transducers in an Intravascular Sonothrombolysis Catheter AU - Zhang, Bohua AU - Wu, Huaiyu AU - Kim, Jinwook AU - Dayton, Paul AU - Xu, Zhen AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - Thrombosis has emerged as one of the primary factors in mortality rates across the world. Conventional thrombolysis treatments for the rapid dissolution or extraction of massive thrombus, including fibrinolytic therapy and surgical thrombectomy, are time-consuming and may induce risks such as bleeding and vessel wall damage. Here we report a novel intravascular sonothrombolysis device with both forward-viewing and side-viewing elements. The developed FSV transducer prototype has a resonance frequency at 520 kHz and peak negative pressure (PNP) at 4.9 MPa (forward-viewing) and 3.2 MPa (side-viewing) under the driving voltage of 80 V pp. The combination of forward and side-viewing (FSV) ultrasound waves is expected to extend the treatment region and improve thrombolysis efficiency compared to a forward or side-viewing alone sonication. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958224 SP - SN - 1948-5719 KW - ultrasound transducers KW - microbubbles KW - thrombus KW - thrombolysis KW - sonothrombolysis ER - TY - JOUR TI - A Dual-Frequency Intravascular Ultrasound Transducer for Amplified Nanodroplet Vaporization Effects in Cavitation-Enhanced Sonothrombolysis AU - Moon, Sunho AU - Wu, Huaiyu AU - Zhang, Bohua AU - Kim, Jinwook AU - Dayton, Paul A. AU - Xu, Zhen AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - Thromboembolism often leads to stroke, myocardial infarction, and other severe complications. There remains a need for new technologies for clinical thrombosis treatment. Sonothrombolysis mediated with cavitation-enhancing agents has shown promise in the treatment of thromboembolism in preclinical studies and clinical trials. Recent works have emphasized specifically efficient sonothrombolysis using phase-change nanodroplets, likely due to their generation of cavitation within the clot matrix. Yet, it has also been reported that nanodroplets might vaporize more effectively under high-frequency excitation and generate more cavitation with low-frequency excitation. Therefore, in this work, a dual-frequency (10 MHz/500 kHz) intravascular transducer intended for nanodroplet-specific sonothrombolysis was developed to improve clot mass reduction rate while retaining lower acoustic pressures than the typical nanodroplet vaporization threshold at sub-megahertz excitation (> 5 MPa). It results in a 34 % improvement of thrombolysis efficiency compared to a single low-frequency excitation. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958578 SP - SN - 1948-5719 KW - Intravascular transducer KW - dual-frequency thrombolysis KW - Nanodroplets ER - TY - JOUR TI - Millisecond-Level Transient Temperature Monitoring Using an Ultra-Fast Response Thermocouple for Ultrasound-Induced Thermal Strain Imaging AU - Chen, Mengyue AU - Zhang, Bohua AU - Kim, Howuk AU - Sheng, Zhiyu AU - Chen, Qiyang AU - Kim, Kang AU - Geng, Xuecang AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - Ultrasound-induced thermal strain imaging (US-TSI) is promising for vulnerable atherosclerosis plaque detection. To avoid arterial motion-induced artifacts, it is needed to induce a very fast temperature rise for US-TSI. Such a short time period for a negligible tissue motion is about 1/8th of a human cardiac cycle, which is corresponding to 75 ms – 125 ms. However, the current temperature monitoring techniques, such as infrared (IR) imaging and magnetic resonance (MR) thermometry, are known with difficulty in monitoring such rapid temperature rises inside biological tissue. Herein, this paper aims to use an ultra-fast response thermocouple to observe rapid temperature rise within 50 ms. Laser-induced thermal tests were conducted in air to verify the feasibility of transient temperature monitoring. Ultrasound-induced thermal tests were conducted in biological tissue to study the influence of various sonication parameters. Obvious transient temperature rises within 50 ms can be observed for both laser tests and tissue tests. The results manifest that the proposed method is capable of monitoring transient temperature rise in biological tissue for US- TSI. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958761 SP - SN - 1948-5719 KW - ultrasound-induced thermal strain imaging KW - ultra-fast response thermocouple KW - transient temperature monitoring ER - TY - JOUR TI - Acoustic Hologram Lens Made of Nanoparticle-Epoxy Composite Molding for Directing Predefined Therapeutic Ultrasound Beams AU - Kim, Jinwook AU - Kasoji, Sandeep AU - Durham, Phillip G. AU - Dayton, Paul A. T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - We present an acoustic hologram lens fabrication method for prototyping nondeformed hologram lenses with a tailored acoustic impedance. A pixelized hologram pattern is typically manufactured by photo-curing 3D printing methods, such as stereolithography (SLA) printing. However, SLA printing has major limitations for lens fabrication: vulnerability to deformation during photo-curing of a thin-plate shape lens structure and limited controllability of acoustic impedance. To overcome these limitations, we adopted a synthesized epoxy composite molding technique in this work. The used alumina nanoparticle (300 nm)-epoxy composite contains 22.5% alumina particles in volume. The characterized acoustic impedance of the composite was 4.68 MRayl whereas the conventional photopolymer exhibited 3.13 MRayl. We used these acoustic properties in lens modeling and acoustic hologram simulations. In simulations, the composite lens generated 145% pressure amplitude of the photopolymer lens due to improved acoustic impedance matching between a piezoelectric ceramic and water medium. We prototyped a composite lens through 1) 3D printing a lens cavity, 2) silicone rubber molding, and 3) epoxy composite lens molding. We observed no deformation of the prototyped composite lens whereas the photopolymer lens showed deformed edges. The beam mapping result using the composite lens showed 17% improved structural similarity with the designed pressure pattern compared to the photopolymer result. Due to the air bubbles trapped in a composite lens, the expected improvement of pressure amplitude over a photopolymer lens was not experimentally demonstrated. The additional degassing procedure will be included for future prototypes and pressure transmission will be evaluated. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9957379 SP - SN - 1948-5719 KW - acoustic hologram KW - acoustic metamaterial KW - beam focusing KW - epoxy composite KW - ultrasound ER - TY - JOUR TI - Intracorporeal Sonoporation-Induced Drug/Gene Delivery Using a Catheter Ultrasound Transducer AU - Chen, Mengyue AU - Kim, Howuk AU - Zhang, Bohua AU - Yang, Waston AU - Osada, Takuya AU - Crosby, Erika J. AU - Lyerly, H. Kim AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - Ultrasound (US) has been recently demonstrated promising in cancer immunotherapy. By virtue of microbubble-mediated cavitation, US can induce temporary pores in the cell membrane to enhance drug/gene delivery and this process is termed sonoporation. Currently, the typical US transducer for sonoporation is extracorporeal, lacking the ability to target lesions behind bones and fat efficiently, as well as to inject microbubbles (MBs) and nucleic acids into the US treatment zone simultaneously. These issues can decrease the drug/gene delivery effectiveness and increase the undesired systemic toxicity for cancer immunotherapy. Here we demonstrated an 800 kHz miniaturized US transducer for intracorporeal sonoporation-induced drug/gene delivery. Acoustic simulation using k-Wave toolbox was carried out to explore the 800 kHz US wave propagation in a 384-well cell culture plate. In-vitro sonoporation tests using human embryonic kidney (HEK) 293T cells and green fluorescent protein-luciferase (GFP-LUC) encoded plasmid DNA were conducted with various sonication parameters (i.e., 0.1 – 0.7 MPa peak-negative pressure; 20 – 2000 cycle number). The LUC assay demonstrated a significantly enhanced transfection, indicating the developed catheter transducer is promising for intracorporeal sonoporation-induced drug/gene delivery, such as intratumoral immunotherapy. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958222 SP - SN - 1948-5719 KW - cancer immunotherapy KW - drug delivery KW - gene delivery KW - intracorporeal sonoporation KW - catheter ultrasound transducer KW - intratumoral immunotherapy ER - TY - JOUR TI - A multi-directional transducer array for muscle shear wave anisotropy estimation AU - Wu, Huaiyu AU - Zhang, Bohua AU - Xu, Guo-Xuan AU - Huang, Chih-Chung AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - Ultrasound elastography based on shear wave imaging has been widely used in clinical applications. However, the elasticity of anisotropic tissues, such as muscle and tendon, cannot be measured accurately using shear wave imaging because the shear wave velocity (SWV) varies with tissue fiber orientations. Recently, some researchers reported that anisotropic properties of muscles can be estimated by rotating the transducer for shear wave imaging. However, this approach may be difficult for clinical practices because of the relatively long data acquisition time and the misalignment errors associated with mechanical rotation of the array. Although fully sampled 2-D array can accomplish rotation electrically, the high cost and complexity of imaging hardware system can be a concern. Thus, in this work, we designed and fabricated a multi-directional transducer array in order to measure SWV for exploring the anisotropic properties of muscles. This novel star-shape transducer includes a middle element to generate acoustic radiation force for creating shear wave in tissue, and another 32 elements was alignment to form 4-element arrays for detecting the shear waves in 8 different directions (360°) without physically rotating the transducer. With a wide −6 dB bandwidth (50.9%) and high sensitivity from the receiving elements, the array showed a great potential in assessment of tissue anisotropy. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958882 SP - SN - 1948-5719 KW - Multi-direction array KW - shear wave ultrasound imaging ER - TY - JOUR TI - Development of a wearable ultrasound transducer for sensing muscle activities in assistive robotics applications: In vivo study AU - Xue, Xiangming AU - Zhang, Bohua AU - Moon, Sunho AU - Xu, Guo-Xuan AU - Huang, Chih-Chung AU - Sharma, Nitin AU - Jiang, Xiaoning T2 - 2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS) AB - People who suffer from the amputation of limbs or with mobility impairment due to methodological disorder sometimes require assistive robotics (AR), such as robotic prostheses and exoskeletons, to function satisfactorily and productively in daily life. Dynamic measurements of muscle voluntary activities are widely used to control AR, and sensors used to control AR should be non-invasive, effective, and wearable. Ultrasound (US) imaging is an effective method for measuring muscle activity. Nevertheless, conventional US transducers are cumbersome and inflexible, making them inconvenient for continuous monitoring of muscle activity for AR control. In light of no report available about using a flexible transducer for detecting muscle activities for AR, this work aims to develop a novel wearable US device for detecting muscle activities. In specific, a 16-element 10 MHz flexible sparse array was designed, fabricated, and characterized. The feasibility of monitoring muscle activity in different regions was demonstrated by an in vivo human experiment. DA - 2022/// PY - 2022/// DO - 10.1109/IUS54386.2022.9958535 SP - SN - 1948-5719 KW - ultrasound transducers KW - wearable transducers KW - flexible transducers KW - muscle activities detection ER - TY - JOUR TI - Amplification of Lamb-Wave Detection via Fiber Bragg Gratings Using Ultrasonic Horns AU - Wang, Chia-Fu AU - Wee, Junghyun AU - Peters, Kara T2 - JOURNAL OF NONDESTRUCTIVE EVALUATION, DIAGNOSTICS AND PROGNOSTICS OF ENGINEERING SYSTEMS AB - Abstract Fiber Bragg grating (FBG) sensors are often applied as Lamb wave detectors for structural health monitoring (SHM) systems. Analyzing the measured signal for the identification of structural damage requires a high signal-to-noise ratio (SNR) because of the low-amplitude Lamb waves. This paper applies a two-dimensional ultrasonic horn between the structure and a remotely bonded FBG sensor to increase the amplitudes of the measured signal. Experimentally we test a variety of ultrasonic geometries and demonstrate a 100% increase in the measured ultrasonic signal amplitude using a metallic ultrasonic horn with step-down geometry. A bonding procedure for the combined ultrasonic horn and optical fiber is also developed that produces repeatable signal measurements. For some horn geometries, an additional vibration signal at the Lamb wave excitation frequency is observed in the measurements. Laser Doppler vibrometry (LDV) measurements and finite element analysis demonstrate that the signal is due to the natural vibration of the horn. The experimental results demonstrate that using an aluminum ultrasonic horn to focus wave is an excellent method to increase the sensitivity of the FBG to the small amplitude Lamb wave, provided the horn vibration characteristics are taken account in the design of the measurement system. DA - 2022/8// PY - 2022/8// DO - 10.1115/1.4053582 VL - 5 IS - 3 SP - SN - 2572-3898 KW - continuous and periodic condition assessment KW - sensors KW - ultrasonics ER - TY - JOUR TI - Anelasticity in thin-shell nanolattices AU - Chen, I-Te AU - Poblete, Felipe Robles AU - Bagal, Abhijeet AU - Zhu, Yong AU - Chang, Chih-Hao T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - In this work, we investigate the anelastic deformation behavior of periodic three-dimensional (3D) nanolattices with extremely thin shell thicknesses using nanoindentation. The results show that the nanolattice continues to deform with time under a constant load. In the case of 30-nm-thick aluminum oxide nanolattices, the anelastic deformation accounts for up to 18.1% of the elastic deformation for a constant load of 500 μN. The nanolattices also exhibit up to 15.7% recovery after unloading. Finite element analysis (FEA) coupled with diffusion of point defects is conducted, which is in qualitative agreement with the experimental results. The anelastic behavior can be attributed to the diffusion of point defects in the presence of a stress gradient and is reversible when the deformation is removed. The FEA model quantifies the evolution of the stress gradient and defect concentration and demonstrates the important role of a wavy tube profile in the diffusion of point defects. The reported anelastic deformation behavior can shed light on time-dependent response of nanolattice materials with implication for energy dissipation applications. DA - 2022/9/20/ PY - 2022/9/20/ DO - 10.1073/pnas.2201589119 VL - 119 IS - 38 SP - SN - 1091-6490 KW - anelasticity KW - 3D nanostructures KW - nanolattices KW - nanoindentation ER - TY - JOUR TI - Ergonomic Assessment of Surgeon Characteristics and Laparoscopic Device Strain in Gynecologic Surgery AU - Wong, Jacqueline M. K. AU - Moore, Kristin J. AU - Lewis, Preston AU - Reid, Monique AU - Saul, Katherine AU - Carey, Erin T. T2 - JOURNAL OF MINIMALLY INVASIVE GYNECOLOGY AB - To evaluate whether surgeon characteristics, including sex and hand size, were associated with grip strength decline with laparoscopic advanced energy devices.Prospective cohort study.Ergonomic simulation at an academic tertiary care site and the Society of Gynecologic Surgeons 47th Annual Meeting.Thirty-eight participants (19 women and 19 men) were recruited.Surgeon anthropometric measurements were collected. Each participant completed a 120-second trial of maximum voluntary effort with 3 laparoscopic advanced energy devices (LigaSure, HALO PKS, and ENSEAL). Grip strength was measured using a handheld dynamometer. Subjects completed the NASA Raw Task Load Index scale after each device trial. Grip strengths and ergonomic workload scores were compared using Student t tests and Wilcoxon rank sum tests where appropriate. Univariate and multivariate models analyzed hand size and ergonomic workload.Women had lower baseline grip strength (288 vs 451 N) than men, as did participants with glove size <7 compared with ≥7 (231 vs 397 N). Normalized grip strength was not associated with surgeon sex (p = .08), whereas it was significantly associated with surgeon glove size (p <.01). Grip strength decline was significantly greater for smaller compared to larger handed surgeons for LigaSure (p = .02) and HALO PKS devices (p <.01). The ergonomic workload of device use was significantly greater for smaller compared to larger handed surgeons (p <.01). Surgeon handspan significantly predicted grip strength decline with device use, even after accounting for potential confounders (R2 = .23, β = .8, p <.01).Surgeons with smaller hand size experienced a greater grip strength decline and greater ergonomic workload during repetitive laparoscopic device use. No relationship was found between surgeon sex and grip strength decline or ergonomic workload. Laparoscopic device type was also identified as a significant main effect contributing to grip strength decline. These findings point toward ergonomic strain stemming from an improper fit between the laparoscopic device and the surgeon's hand during device use. DA - 2022/12// PY - 2022/12// DO - 10.1016/j.jmig.2022.09.552 VL - 29 IS - 12 SP - 1357-1363 SN - 1553-4669 KW - Gynecologic surgical procedures KW - Minimally invasive surgery KW - Occupational diseases KW - Sex bias KW - Surgical instruments ER - TY - JOUR TI - Highly Sensitive, Stretchable, and Robust Strain Sensor Based on Crack Propagation and Opening AU - Wu, Shuang AU - Moody, Katherine AU - Kollipara, Abhiroop AU - Zhu, Yong T2 - ACS APPLIED MATERIALS & INTERFACES AB - Soft and stretchable strain sensors have been attracting significant attention. However, the trade-off between the sensitivity (gauge factor) and the sensing range has been a major challenge. In this work, we report a soft stretchable resistive strain sensor with an unusual combination of high sensitivity, large sensing range, and high robustness. The sensor is made of a silver nanowire network embedded below the surface of an elastomeric matrix (e.g., poly(dimethylsiloxane)). Periodic mechanical cuts are applied to the top surface of the sensor, changing the current flow from uniformly across the sensor to along the conducting path defined by the open cracks. Both experiment and finite element analysis are conducted to study the effect of the slit depth, slit length, and pitch between the slits. The stretchable strain sensor can be integrated into wearable systems for monitoring physiological functions and body motions associated with different levels of strain, such as blood pressure and lower back health. Finally, a soft three-dimensional (3D) touch sensor that tracks both normal and shear stresses is developed for human-machine interfaces and tactile sensing for robotics. DA - 2022/12/22/ PY - 2022/12/22/ DO - 10.1021/acsami.2c16741 SP - SN - 1944-8252 KW - strain sensor KW - silver nanowires KW - crack KW - stretchable electronics KW - health monitoring KW - human-machine interface ER - TY - JOUR TI - Curvilinear soft electronics by micromolding of metal nanowires in capillaries AU - Liu, Yuxuan AU - Zheng, Michael AU - O'Connor, Brendan AU - Dong, Jingyan AU - Zhu, Yong T2 - SCIENCE ADVANCES AB - Soft electronics using metal nanowires have attracted notable attention attributed to their high electrical conductivity and mechanical flexibility. However, high-resolution complex patterning of metal nanowires on curvilinear substrates remains a challenge. Here, a micromolding-based method is reported for scalable printing of metal nanowires, which enables complex and highly conductive patterns on soft curvilinear and uneven substrates with high resolution and uniformity. Printing resolution of 20 μm and conductivity of the printed patterns of ~6.3 × 106 S/m are achieved. Printing of grid structures with uniform thickness for transparent conductive electrodes (TCEs) and direct printing of pressure sensors on curved surfaces such as glove and contact lens are also realized. The printed hybrid soft TCEs and smart contact lens show promising applications in optoelectronic devices and personal health monitoring, respectively. This printing method can be extended to other nanomaterials for large-scale printing of high-performance soft electronics. DA - 2022/11/16/ PY - 2022/11/16/ DO - 10.1126/sciadv.add6996 VL - 8 IS - 46 SP - SN - 2375-2548 ER - TY - JOUR TI - Snapping for high-speed and high-efficient butterfly stroke-like soft swimmer AU - Chi, Yinding AU - Hong, Yaoye AU - Zhao, Yao AU - Li, Yanbin AU - Yin, Jie T2 - SCIENCE ADVANCES AB - Natural selection has tuned many flying and swimming animals to share the same narrow design space for high power efficiency, e.g., their dimensionless Strouhal numbers St that relate flapping frequency and amplitude and forward speed fall within the range of 0.2 < St < 0.4 for peak propulsive efficiency. It is rather challenging to achieve both comparably fast-speed and high-efficient soft swimmers to marine animals due to the naturally selected narrow design space and soft body compliance. Here, bioinspired by the flapping motion in swimming animals, we report leveraging snapping instabilities for soft flapping-wing swimmers with comparable high performance to biological counterparts. The lightweight, butterfly stroke-like soft swimmer (2.8 g) demonstrates a record-high speed of 3.74 body length/s (4.8 times faster than the reported fastest flapping soft swimmer), high power efficiency (0.2 < St = 0.25 < 0.4), low energy consumption cost, and high maneuverability (a high turning speed of 157°/s). DA - 2022/11/16/ PY - 2022/11/16/ DO - 10.1126/sciadv.add3788 VL - 8 IS - 46 SP - SN - 2375-2548 ER - TY - JOUR TI - Guided waves based damage localization using acoustically coupled optical fibers and a single fiber Bragg grating sensor AU - Soman, Rohan AU - Kim, Jee Myung AU - Aiton, Sean AU - Peters, Kara T2 - MEASUREMENT AB - Fiber Bragg grating (FBG) sensors have long been thought of as the ideal sensors for structural health monitoring (SHM) due to their small size, light weight, ability to be embedded and ability to be multiplexed. So, FBG sensors have been commonly used for strain based SHM. In recent times, a renewed interest is seen in the use of FBG sensors for GW measurements using the edge filtering approach which increases the sensitivity several fold. The remote bonding configuration has also been proposed to enhance this sensitivity further. But in order to achieve damage localization, a multi-sensor network is needed. The FBG sensors and the equipment for employing them in the edge filtering configuration is expensive. As a result, their use for SHM in large structures is still limited. Recent studies have shown that the acoustic wave in an optical fiber may be transferred from one optical fiber to another through an adhesive based acoustic coupler. In this study, this phenomenon is used to develop an SHM system which is capable of damage localization using a single FBG sensor. The paper presents a proof-of-concept of the use of the acoustically coupled optical fibers and single FBG for damage localization. The paper also highlights the design considerations of an acoustic coupler and discusses them in detail. The proposed approach has a potential to radically reduce the equipment costs (factor of 3) which is one of the limiting factors in the widespread acceptance of SHM systems in structures. DA - 2022/11// PY - 2022/11// DO - 10.1016/j.measurement.2022.111985 VL - 203 SP - SN - 1873-412X KW - Acoustic coupler KW - Guided waves (GW) KW - Fiber Bragg grating (FBG) sensors KW - Damage localization KW - Remote sensor ER - TY - JOUR TI - The Dynamic Response of Additively Manufactured Polymers Subjected to Tensile Loading AU - Chadwell, C. AU - Rocco, A. AU - Pankow, M. T2 - JOURNAL OF DYNAMIC BEHAVIOR OF MATERIALS DA - 2022/12/20/ PY - 2022/12/20/ DO - 10.1007/s40870-022-00361-8 SP - SN - 2199-7454 KW - Dynamic KW - Hopkinson bar KW - AM KW - Rate dependent KW - 3D printed ER - TY - JOUR TI - The Challenges of Modeling Defect Behavior and Plasticity across Spatial and Temporal Scales: A Case Study of Metal Bilayer Impact AU - Granger, Leah AU - Chen, Muh-Jang AU - Brenner, Donald AU - Zikry, Mohammed T2 - METALS AB - Atomistic molecular dynamics (MD) and a microstructural dislocation density-based crystalline plasticity (DCP) framework were used together across time scales varying from picoseconds to nanoseconds and length scales spanning from angstroms to micrometers to model a buried copper–nickel interface subjected to high strain rates. The nucleation and evolution of defects, such as dislocations and stacking faults, as well as large inelastic strain accumulations and wave-induced stress reflections were physically represented in both approaches. Both methods showed similar qualitative behavior, such as defects originating along the impactor edges, a dominance of Shockley partial dislocations, and non-continuous dislocation distributions across the buried interface. The favorable comparison between methods justifies assumptions used in both, to model phenomena, such as the nucleation and interactions of single defects and partials with reflected tensile waves, based on MD predictions, which are consistent with the evolution of perfect and partial dislocation densities as predicted by DCP. This substantiates how the nanoscale as modeled by MD is representative of microstructural behavior as modeled by DCP. DA - 2022/12// PY - 2022/12// DO - 10.3390/met12122036 VL - 12 IS - 12 SP - SN - 2075-4701 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85144831580&partnerID=MN8TOARS KW - molecular dynamics KW - dislocation density-based crystalline plasticity KW - dislocations KW - stacking faults KW - partial dislocation densities KW - spall ER - TY - JOUR TI - Self-Sustained Snapping Drives Autonomous Dancing and Motion in Free-Standing Wavy Rings AU - Zhao, Yao AU - Hong, Yaoye AU - Qi, Fangjie AU - Chi, Yinding AU - Su, Hao AU - Yin, Jie T2 - ADVANCED MATERIALS AB - Harnessing snapping, an instability phenomenon observed in nature (e.g., Venus flytraps), for autonomy has attracted growing interest in autonomous soft robots. However, achieving self-sustained snapping and snapping-driven autonomous motions in soft robots remains largely unexplored. Here, harnessing bistable, ribbon ring-like structures for realizing self-sustained snapping in a library of soft liquid-crystal elastomer wavy rings under constant thermal and photothermal actuation are reported. The self-sustained snapping induces continuous ring flipping that drives autonomous dancing or crawling motions on the ground and underwater. The 3D, free-standing wavy rings employ either a highly symmetric or symmetry-broken twisted shape with tunable geometric asymmetries. It is found that the former favors periodic self-dancing motion in place due to isotropic friction, while the latter shows a directional crawling motion along the predefined axis of symmetry during fabrication due to asymmetric friction. It shows that the crawling speed can be tuned by the geometric asymmetries with a peak speed achieved at the highest geometric asymmetry. Lastly, it is shown that the autonomous crawling ring can also adapt its body shape to pass through a confined space that is over 30% narrower than its body size. DA - 2022/12/27/ PY - 2022/12/27/ DO - 10.1002/adma.202207372 VL - 12 SP - SN - 1521-4095 KW - autonomous KW - bistable rings KW - liquid-crystal elastomers KW - snapping instabilities KW - soft robots ER - TY - JOUR TI - A hybrid disturbance observer for delivery drone?s oscillation suppression AU - Chen, Zhu AU - Liu, Chang AU - Su, Hao AU - Liang, Xiao AU - Zheng, Minghui T2 - MECHATRONICS AB - This paper proposes a new hybrid disturbance observer (DOB) to help suppress disturbance to the control systems. The proposed hybrid DOB consists of three main parts: (1) an actual system, (2) a simulated system, and (3) a learning filter that connects the actual and simulated systems. The simulated system aims to replicate the actual system response, where it leverages a neural network model to predict the input disturbance and generate the predicted system response. Such system response is used to generate a learning signal through a learning filter; this learning signal is then added to the feedforward loop of the estimation framework to enhance the disturbance estimate and its suppression performance for the actual system. The proposed hybrid DOB is designed to advance the standard DOB structure with a learning-based feedforward compensation. While the proposed method does not modify the baseline controller, it is well suited to systems whose baseline controllers are difficult or impossible to be changed. Considering the delivery drones are subject to oscillations when dropping payloads, experimental tests with multiple payload dropping scenarios have been conducted using both the hybrid and standard DOB, where the compared results validate the effectiveness and advantages of the proposed hybrid DOB. DA - 2022/12// PY - 2022/12// DO - 10.1016/j.mechatronics.2022.102907 VL - 88 SP - SN - 0957-4158 KW - DOB design KW - Learning filter KW - Neural network KW - Delivery drones ER - TY - JOUR TI - Super-Wideband Electromagnetic Absorbing TiC/SiOC Ceramic/Glass Composites Derived from Polysiloxane and Titanium Isopropoxide with Low Thickness (<1 mm) AU - Yang, Ni AU - Xu, Shaofan AU - Zhang, Dajie AU - Xu, Chengying T2 - ADVANCED ENGINEERING MATERIALS AB - Herein, TiC/SiOC ceramic/glass composites with excellent electromagnetic wave (EMW) absorbing performance are fabricated by pyrolysis of polycarbosiloxane and titanium (IV) isopropoxide (TTIP). By taking advantage of the polymer‐derived route, the phase compositions and microstructures are easily tuned. The composites are investigated by X‐ray diffraction (XRD) analysis, scanning electron microscope, and transmission electron microscopy/energy dispersive spectroscopy. Nanoscaled TiC is formed and uniformly distributed without clustering within the SiOC matrix. Thermogravimetric Analysis (TGA) and in situ XRD results revealed good thermal stability and oxidation resistance mechanism. The presented material system (TiC/SiOC) shows a super‐wide microwave absorption bandwidth (EAB) of 13.5 GHz, including the entire Ka‐band (26.5–40 GHz) with a low thickness requirement (<1 mm). The superior EMW absorption properties of the ceramics are attributed to the optimal interface polarization, as well as the ordering, concentration, and interconnectivity of the conductive network, which all determine the electrical conductivity in the composites. DA - 2022/12/15/ PY - 2022/12/15/ DO - 10.1002/adem.202201508 VL - 12 SP - SN - 1527-2648 KW - electromagnetic (EMW) absorption KW - phase separation KW - polymer-derived ceramics KW - transition metal carbide KW - wide-band absorption ER - TY - JOUR TI - Combined resonance of pulsatile flow-transporting FG nanotubes under forced excitation with movable boundary AU - Jin, Qiduo AU - Ren, Yiru AU - Yuan, Fuh-Gwo T2 - NONLINEAR DYNAMICS DA - 2022/12/20/ PY - 2022/12/20/ DO - 10.1007/s11071-022-08148-1 SP - SN - 1573-269X KW - Combined resonance KW - Incremental harmonic balance method KW - Nonlocal strain gradient theory incorporating surface elasticity KW - Inertia nonlinearity KW - Curvature nonlinearity ER - TY - JOUR TI - Molecular dynamics simulation of steady-state droplet condensation on a fiber in direct contact membrane distillation settings AU - Raza, Saqlain AU - He, Jixiong AU - Tafreshi, Hooman V. AU - Liu, Jun T2 - JOURNAL OF MOLECULAR LIQUIDS AB - • Dynamics of droplet condensation-evaporation was simulated in Direct Contact Membrane Distillation (DCMD) environment. • A novel methodology for achieving steady-state supply of water during an infinitely long period was developed. • The fiber was modelled as a tri-layer structure for appropriate depiction of the actual process. • Droplet formation on fibers can be prevented if the fiber’s Young-Laplace contact angle is greater than a critical value. • Our work provides design guidelines for DCMD membranes based on geometric and operational parameters. Understanding the dynamics of droplet condensation–evaporation behavior on fibers is important for improving the performance of fibrous membranes that are used in water purification applications, e.g., Direct Contact Membrane Distillation (DCMD). DCMD is a promising method of purifying water when low-grade waste heat or renewable energies are available. However, DCMD suffers from low throughput mass flux, and it is also prone to membrane flooding. We used molecular dynamics simulations in this work as the conventional (experimental or computational) methods do not have the required atomistic resolution to reveal the dynamics of water condensation–evaporation on the surface of fibers. Our simulations indicate that vapor flux across the membrane remains constant (with no droplet formation on the fiber) when the fibers’ Young–Laplace Contact Angle (YLCA) is greater than a critical value at which condensation is suppressed. However, mass flux decreases with time at lower YLCAs due to the formation and growth of water droplets on the fibers, which could ultimately lead to membrane flooding. We also studied the impact of feed temperature, permeate temperature, fiber diameter, fiber position, and domain size on the fiber critical YLCA. Optimizing these parameters allows the use of a wide array of materials in membrane fabrication, including even hydrophilic materials, while preventing membrane flooding and also enhancing mass flux. In this work, we also present a novel methodology to simulate steady-state droplet condensation–evaporation process in the framework of molecular dynamics simulation, i.e., simulation times >∼10 ns, in contrast to the quasi-steady-state simulations (simulation time <∼2 ns) reported in most previous studies. Our work demonstrates a simulation platform to study the dynamics of the water condensation–evaporation on fibers and can be used to guide the design of DCMD membranes. DA - 2022/12/15/ PY - 2022/12/15/ DO - 10.1016/j.molliq.2022.120736 VL - 368 SP - SN - 1873-3166 UR - http://dx.doi.org/10.1016/j.molliq.2022.120736 KW - Molecular dynamics simulation KW - Direct contact membrane distillation KW - Desalination KW - Evaporation modelling KW - Condensation modelling KW - Steady-state evaporation KW - Droplet condensation ER - TY - JOUR TI - Numerical and experimental evaluation of low-intensity transcranial focused ultrasound wave propagation using human skulls for brain neuromodulation AU - Chen, Mengyue AU - Peng, Chang AU - Wu, Huaiyu AU - Huang, Chih-Chung AU - Kim, Taewon AU - Traylor, Zachary AU - Muller, Marie AU - Chhatbar, Pratik Y. AU - Nam, Chang S. AU - Feng, Wuwei AU - Jiang, Xiaoning T2 - MEDICAL PHYSICS AB - Low-intensity transcranial focused ultrasound (tFUS) has gained considerable attention as a promising noninvasive neuromodulatory technique for human brains. However, the complex morphology of the skull hinders scholars from precisely predicting the acoustic energy transmitted and the region of the brain impacted during the sonication. This is due to the fact that different ultrasound frequencies and skull morphology variations greatly affect wave propagation through the skull.Although the acoustic properties of human skull have been studied for tFUS applications, such as tumor ablation using a multielement phased array, there is no consensus about how to choose a single-element focused ultrasound (FUS) transducer with a suitable frequency for neuromodulation. There are interests in exploring the magnitude and dimension of tFUS beam through human parietal bone for modulating specific brain lobes. Herein, we aim to investigate the wave propagation of tFUS on human skulls to understand and address the concerns above.Both experimental measurements and numerical modeling were conducted to investigate the transmission efficiency and beam pattern of tFUS on five human skulls (C3 and C4 regions) using single-element FUS transducers with six different frequencies (150-1500 kHz). The degassed skull was placed in a water tank, and a calibrated hydrophone was utilized to measure acoustic pressure past it. The cranial computed tomography scan data of each skull were obtained to derive a high-resolution acoustic model (grid point spacing: 0.25 mm) in simulations. Meanwhile, we modified the power-law exponent of acoustic attenuation coefficient to validate numerical modeling and enabled it to be served as a prediction tool, based on the experimental measurements.The transmission efficiency and -6 dB beamwidth were evaluated and compared for various frequencies. An exponential decrease in transmission efficiency and a logarithmic decrease of -6 dB beamwidth with an increase in ultrasound frequency were observed. It is found that a >750 kHz ultrasound leads to a relatively lower tFUS transmission efficiency (<5%), whereas a <350 kHz ultrasound contributes to a relatively broader beamwidth (>5 mm). Based on these observations, we further analyzed the dependence of tFUS wave propagation on FUS transducer aperture size.We successfully studied tFUS wave propagation through human skulls at different frequencies experimentally and numerically. The findings have important implications to predict tFUS wave propagation for ultrasound neuromodulation in clinical applications, and guide researchers to develop advanced ultrasound transducers as neural interfaces. DA - 2022/11/24/ PY - 2022/11/24/ DO - 10.1002/mp.16090 SP - SN - 2473-4209 KW - human skull KW - transcranial focused ultrasound KW - ultrasonic neuromodulation KW - ultrasound transducer ER - TY - JOUR TI - Ultrasound and magnetic dual-mode stacked transducer for sonothrombolysis with a combination of nanodroplets and magnetic nanoparticles AU - Zhang, Bohua AU - Wu, Huaiyu AU - Jiang, Xiaoning T2 - 2022 IEEE 22ND INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY (NANO) AB - It has been observed that ultrasound thrombolysis is more effective and safer than conventional techniques of thrombolysis, such as mechanical thrombectomy or pharmaceutical medication therapies. Recent work also reported that the dual-mode excitation combining magnetic field and ultrasound helped dramatically increase the thrombolysis rate. Therefore, in this work, based on the dual-mode concept, we demonstrated a 4-element stacked transducer with a center frequency of 450 kHz, which can create ultrasonic waves in addition to a high frequency oscillating magnetic field to activate the superparamagnetic iron oxide nanoparticles (SPIONs) and nanodroplets. Under 250 Vpp input voltage, the transducer reached a peak-negative pressure of 3 MPa. The transducer can simultaneously generate ultrasound cavitation and magnetic pulse excitation, thus providing higher thrombolysis efficiency. DA - 2022/// PY - 2022/// DO - 10.1109/NANO54668.2022.9928649 SP - 71-74 SN - 1944-9380 ER - TY - JOUR TI - Electrothermally Actuated Semitransparent Shape Memory Polymer Composite with Application as a Wearable Touch Sensor AU - Booth, Ronald E. AU - Khanna, Chetna AU - Schrickx, Harry M. AU - Siddika, Salma AU - Al Shafe, Abdullah AU - Brendan T. O'Connor, T2 - ACS APPLIED MATERIALS & INTERFACES AB - A semitransparent shape memory polymer (SMP):silver nanowire (AgNW) composite is demonstrated to be capable of low-temperature actuation, thus making it attractive for wearable electronics applications that require intimate contact with the human body. We demonstrate that the SMP:AgNW composite has tunable electrical and optical transparency through variation of the AgNW loading and that the AgNW loading did not significantly change the mechanical behavior of the SMP. The SMP composite is also capable of electrical actuation through Joule heating, where applying a 4 V bias across the AgNWs resulted in full shape recovery. The SMP was found to have high strain sensitivity at both small (<1%) and large (over 10%) applied strain. The SMP could sense strains as low as 0.6% with a gauge factor of 8.2. The SMP composite was then utilized as a touch sensor, able to sense and differentiate tapping and pressing. Finally, the composite was applied as a wearable ring that was thermally actuated to conformably fit onto a finger as a touch sensor. The ring sensor was able to sense finger tapping, pressing, and bending with high signal-to-noise ratios. These results demonstrate that SMP:AgNW composites are a promising design approach for application in wearable electronics. DA - 2022/11/16/ PY - 2022/11/16/ DO - 10.1021/acsami.2c10290 SP - SN - 1944-8252 KW - wearable electronics KW - shape memory polymer KW - silver nanowire KW - wearable touch sensor KW - electrothermal actuation ER - TY - JOUR TI - Bio-inspired design of a self-aligning, lightweight, and highly-compliant cable-driven knee exoskeleton AU - Yu, Shuangyue AU - Huang, Tzu-Hao AU - Di Lallo, Antonio AU - Zhang, Sainan AU - Wang, Tian AU - Fu, Qiushi AU - Su, Hao T2 - FRONTIERS IN HUMAN NEUROSCIENCE AB - Powered knee exoskeletons have shown potential for mobility restoration and power augmentation. However, the benefits of exoskeletons are partially offset by some design challenges that still limit their positive effects on people. Among them, joint misalignment is a critical aspect mostly because the human knee joint movement is not a fixed-axis rotation. In addition, remarkable mass and stiffness are also limitations. Aiming to minimize joint misalignment, this paper proposes a bio-inspired knee exoskeleton with a joint design that mimics the human knee joint. Moreover, to accomplish a lightweight and high compliance design, a high stiffness cable-tension amplification mechanism is leveraged. Simulation results indicate our design can reduce 49.3 and 71.9% maximum total misalignment for walking and deep squatting activities, respectively. Experiments indicate that the exoskeleton has high compliance (0.4 and 0.1 Nm backdrive torque under unpowered and zero-torque modes, respectively), high control bandwidth (44 Hz), and high control accuracy (1.1 Nm root mean square tracking error, corresponding to 7.3% of the peak torque). This work demonstrates performance improvement compared with state-of-the-art exoskeletons. DA - 2022/11/7/ PY - 2022/11/7/ DO - 10.3389/fnhum.2022.1018160 VL - 16 SP - SN - 1662-5161 KW - bioinspired design KW - cable-driven KW - self-alignment KW - knee exoskeleton KW - complaint actuators ER - TY - JOUR TI - Resonance interaction of flow-conveying nanotubes under forced vibration AU - Jin, Qiduo AU - Yuan, Fuh-Gwo AU - Ren, Yiru T2 - ACTA MECHANICA DA - 2022/11/23/ PY - 2022/11/23/ DO - 10.1007/s00707-022-03425-x SP - SN - 1619-6937 ER - TY - BOOK TI - Tribology in manufacturing processes : selected peer-reviewed full text papers from the 9th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation (ICTMP2021 : November 24-26, 2021, Chennai, India A3 - Ngaile, Gracious A3 - Montmitonnet, Pierre A3 - Dohda, Kuniaki DA - 2022/// PY - 2022/// PB - Scientific.Net, Trans Tech Publications Ltd SN - 9783035717242 ER - TY - JOUR TI - A low-order wake interaction modeling framework for the performance of ocean current turbines under turbulent conditions AU - Razi, P. AU - Ramaprabhu, P. AU - Tarey, P. AU - Muglia, M. AU - Vermillion, C. T2 - RENEWABLE ENERGY AB - Understanding the effects of ambient turbulence (expressed often in terms of the turbulence intensity It) is critical to the development of predictive models for the performance of Ocean Current Turbine (OCTs). This paper describes a new, wake interaction modeling framework capable of capturing the detailed effects of turbulence on various performance parameters associated with OCTs that may be arranged in any arbitrary configuration. The model accounts for the effects of turbulence on the structure of the turbine wakes, specifically the extents of near- and far-wake regions, and the dependence of the transition point between the two regions on It. The analytical description for turbine wake is combined with an existing wake interaction model, the Unrestricted Wind Farm Layout Optimization (UWFLO) model to predict the global power output from an array of OCTs. The resulting modelling framework accurately captures the effect of inlet turbulence on the OCT farm power and efficiency, and can be applied to any array configuration. Results from the model are validated against Large Eddy Simulations (LES) in which the OCTs are modeled using the Blade Element Momentum (BEM) model, while the inlet flow is superposed with a synthetic turbulence field designed to approximate turbulence properties obtained from observational measurements of the Gulf Stream. The simulations show that OCT wakes recover faster at higher levels of inlet turbulence due to the enhanced entrainment and mixing between ambient flow and the wake, an effect that is captured by the modified UWFLO model. DA - 2022/11// PY - 2022/11// DO - 10.1016/j.renene.2022.10.001 VL - 200 SP - 1602-1617 SN - 1879-0682 KW - Ocean current turbine arrays KW - Large eddy simulation KW - Wake interaction models KW - ocean energy ER - TY - JOUR TI - Recent Advances in Tracking Devices for Biomedical Ultrasound Imaging Applications AU - Peng, Chang AU - Cai, Qianqian AU - Chen, Mengyue AU - Jiang, Xiaoning T2 - MICROMACHINES AB - With the rapid advancement of tracking technologies, the applications of tracking systems in ultrasound imaging have expanded across a wide range of fields. In this review article, we discuss the basic tracking principles, system components, performance analyses, as well as the main sources of error for popular tracking technologies that are utilized in ultrasound imaging. In light of the growing demand for object tracking, this article explores both the potential and challenges associated with different tracking technologies applied to various ultrasound imaging applications, including freehand 3D ultrasound imaging, ultrasound image fusion, ultrasound-guided intervention and treatment. Recent development in tracking technology has led to increased accuracy and intuitiveness of ultrasound imaging and navigation with less reliance on operator skills, thereby benefiting the medical diagnosis and treatment. Although commercially available tracking systems are capable of achieving sub-millimeter resolution for positional tracking and sub-degree resolution for orientational tracking, such systems are subject to a number of disadvantages, including high costs and time-consuming calibration procedures. While some emerging tracking technologies are still in the research stage, their potentials have been demonstrated in terms of the compactness, light weight, and easy integration with existing standard or portable ultrasound machines. DA - 2022/11// PY - 2022/11// DO - 10.3390/mi13111855 VL - 13 IS - 11 SP - SN - 2072-666X KW - tracking KW - ultrasound imaging KW - optical tracking KW - electromagnetic tracking KW - 3D ultrasound imaging KW - ultrasound-guided interventions KW - ultrasound image fusion ER - TY - JOUR TI - Low-Order Modeling of Dynamic Stall on Airfoils in Incompressible Flow AU - Narsipur, Shreyas AU - Gopalarathnam, Ashok AU - Edwards, Jack R. T2 - AIAA JOURNAL AB - Airfoil dynamic stall in incompressible flow is characterized by two interacting viscous flow phenomena: time-varying trailing-edge separation and the shedding of intermittent leading-edge-vortex structures. In the current work, a physics based low-order method capable of modeling the interactions between the two flow phenomena is developed with the aim of predicting dynamic stall with only a few empirical tuning parameters. Large computational datasets are used to understand the flow physics of unsteady airfoils so as to augment an inviscid, unsteady airfoil theory to model the time-dependent viscous effects. The resulting model requires only three empirical coefficients for a given airfoil and Reynolds number, which could be obtained from a single moderate-pitch-rate unsteady motion for that airfoil/Reynolds number combination. Results from the low-order model are shown to compare excellently with computational and experimental solutions, in terms of both aerodynamic loads and flow-pattern predictions. In addition to formulating a method with limited empirical dependencies, the current research provides valuable insights into the flow physics of unsteady airfoils and their connection to rapidly predictable theoretical parameters. DA - 2022/9/7/ PY - 2022/9/7/ DO - 10.2514/1.J061595 SP - SN - 1533-385X ER - TY - JOUR TI - A Review on Alternating Current Poling for Perovskite to Relaxor-PbTio(3) Single Crystals AU - Kim, Hwang-Pill AU - Wan, Haotian AU - Luo, Chengtao AU - Sun, Yiqin AU - Yamashita, Yohachi AU - Karaki, Tomoaki AU - Lee, Ho-Yong AU - Jiang, Xiaoning T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - With the great success on verifying its effectiveness on relaxor-PbTiO3 (PT) single crystals (SCs), alternating current poling (ACP) has been taking a center as a new domain engineering method in the last few years. Compared with the conventional direct current poling (DCP), ACP enables enhanced piezoelectric and dielectric properties. In this article, research progress in ACP and perspectives are introduced. Initially, optimized conditions of ACP for relaxor-PT SCs and unsolved issues on polycrystalline ceramics and spurious modes are reviewed. Second, the ferroelectric domain size dependence of piezoelectricity associated with ACP is discussed. We hypothesize that a tradeoff between domain and domain wall contributions exists for high piezoelectricity, suggesting an optimum 109° domain wall size, which is presumably dependent on compositions, crystallographic symmetries, and domain configurations. Finally, crystals synthesized by a solid-state crystal growth (SSCG) method are briefly introduced due to their unprecedented piezoelectricity obtained by ACP ( ${d}_{33} \sim 5500$ pC/N). We hope that this work helps to grasp the current status of ACP and to guide future tasks to be studied. DA - 2022/11// PY - 2022/11// DO - 10.1109/TUFFC.2022.3181236 VL - 69 IS - 11 SP - 3037-3047 SN - 1525-8955 KW - Alternate current poling (ACP) KW - domain engineering KW - piezoelectric materials KW - relaxor-PbTiO3 (PT) single crystals (SCs) KW - transducers ER - TY - JOUR TI - A Review of Lead Perovskite Piezoelectric Single Crystals and Their Medical Transducers Application AU - Yamashita, Yohachi AU - Karaki, Tomoaki AU - Lee, Ho-Yong AU - Wan, Haotian AU - Kim, Hwang-Pill AU - Jiang, Xiaoning T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - Piezoelectric materials have been developed since early 1900s and many research had been conducted on the composition and process to obtain higher piezoelectric constants ( ${d}_{33}$ ). Within composition research, lead perovskite relaxor piezoelectric single crystals (SCs) of Pb(Mg1/3Nb2/3)O3–lead titanate PbTiO3 type have been actively studied since 1990s because of their outstanding ${d}_{33} >1500$ pC/N compared with those of the conventional Pb(Zr,Ti)O3 ceramics. A major driving force of these SC research has been promoted by mass production of ultrasound transducers and array probes for medical diagnostic systems since early 2000s. However, higher ${d}_{33}$ material and process research for these ultrasound devices are almost saturated. In this review article, we present a brief overview of the history, current situation, and future perspective of piezoelectric SCs. The authors believe that the main research in the next century is high ${d}_{33}$ SCs with a high composition uniformity and low-energy SC growth methods, such as solid-state SC growth, low-loss SC transducer manufacturing technique, and improved poling process. This is a big technical challenge for all the scientists; however, the relatively large market of medical ultrasound has been expanded year by year, and we hope that the community is motivated to solve such technical problems in the near future. DA - 2022/11// PY - 2022/11// DO - 10.1109/TUFFC.2022.3160526 VL - 69 IS - 11 SP - 3048-3056 SN - 1525-8955 KW - Crystal growth KW - lead titanate KW - piezoelectric materials KW - relaxor KW - single crystals (SCs) KW - ultrasound imaging ER - TY - JOUR TI - Enhanced Properties of 3-MHz Sliver-Mode Vibrators for Cardiac Probes With Alternating Current Poling for Pb(Mg1/3Nb2/3)O-3-PbTiO3 Single Crystals AU - Sun, Yiqin AU - Ota, Yuhei AU - Fujii, Tadashi AU - Yamashita, Yohachi AU - Kim, Hwang-Pill AU - Wan, Haotian AU - Jiang, Xiaoning AU - Karaki, Tomoaki T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - We investigated the effects of alternating current poling (ACP) on the piezoelectric and dielectric properties of 3-MHz sliver mode (L13 mm × W0.10-0.25 mm × T0.48 mm) vibrators fashioned from Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PMN-0.30PT) single crystal (SC) plate manufactured using the continuous-feeding Bridgman (CF-BM) method for cardiac probes. The ACP SC plate (L13 mm × W24 mm × T0.48 mm) exhibited ultrahigh dielectric permittivity ( εT33/ε0 ) and piezoelectric coefficient ( d33 ) of 9690 and 2920 pC/N, respectively. After array dicing, the SC slivers with widths of 0.10, 0.15, 0.20, and 0.25 mm were obtained, and their average εT33/ε0 values decreased from the SC plate εT33/ε0 by 45% (5330), 29% (6880), 19% (7840), and 15% (8240), respectively, possibly because of heat and mechanical damage during the dicing. A combination of the ACP and a postdicing direct current poling (ACP-DCP) recovered their εT33/ε0 values to 6050, 7080, 8140, and 8540, respectively. The sliver mode electromechanical coupling factors ( k'33 ) were confirmed to exceed 93% after the ACP-DCP process, which were more than 4% higher than those of DCP-DCP SC slivers. The measured impedance spectra indicated that the SC slivers with 0.10-0.20 mm in width showed no spurious mode vibration near the fundamental k'33 mode. We conclude that the ACP-DCP SC slivers maintained more enhanced piezoelectric and dielectric properties than the DCP-DCP samples. These results will have important implications for the commercial application of ACP technology to medical imaging ultrasound probes. DA - 2022/11// PY - 2022/11// DO - 10.1109/TUFFC.2022.3199741 VL - 69 IS - 11 SP - 3087-3094 SN - 1525-8955 KW - Alternating current poling (ACP) KW - continuous-feeding bridgman (CF-BM) KW - medical transducer KW - single crystals (SCs) ER - TY - JOUR TI - How can wearable robotic and sensor technology advance neurorehabilitation? AU - Chang, Shuo-Hsiu AU - Tseng, Shih-Chiao AU - Su, Hao AU - Francisco, Gerard E. T2 - FRONTIERS IN NEUROROBOTICS AB - EDITORIAL article Front. Neurorobot., 11 October 2022 Volume 16 - 2022 | https://doi.org/10.3389/fnbot.2022.1033516 DA - 2022/10/11/ PY - 2022/10/11/ DO - 10.3389/fnbot.2022.1033516 VL - 16 SP - SN - 1662-5218 KW - wearable robotics KW - wearable sensors KW - rehabilitation KW - neurorehabilitation KW - rehabilitation technology ER - TY - JOUR TI - Wing sweep effects on laminar separated flows AU - Ribeiro, Jean Helder Marques AU - Yeh, Chi-An AU - Zhang, Kai AU - Taira, Kunihiko T2 - JOURNAL OF FLUID MECHANICS AB - We reveal the effects of sweep on the wake dynamics around NACA 0015 wings at high angles of attack using direct numerical simulations and resolvent analysis. The influence of sweep on the wake dynamics is considered for sweep angles from $0^\circ$ to $45^\circ$ and angles of attack from $16^\circ$ to $30^\circ$ for a spanwise periodic wing at a chord-based Reynolds number of $400$ and a Mach number of $0.1$ . Wing sweep affects the wake dynamics, especially in terms of stability and spanwise fluctuations with implications on the development of three-dimensional (3-D) wakes. We observe that wing sweep attenuates spanwise fluctuations. Even as the sweep angle influences the wake, force and pressure coefficients can be collapsed for low angles of attack when examined in wall-normal and wingspan-normal independent flow components. Some small deviations at high sweep and incidence angles are attributed to vortical wake structures that impose secondary aerodynamic loads, revealed through the force element analysis. Furthermore, we conduct global resolvent analysis to uncover oblique modes with high disturbance amplification. The resolvent analysis also reveals the presence of wavemakers in the shear-dominated region associated with the emergence of 3-D wakes at high angles of attack. For flows at high sweep angles, the optimal convection speed of the response modes is shown to be faster than the optimal wavemakers speed suggesting a mechanism for the attenuation of perturbations. The present findings serve as a fundamental stepping stone to understanding separated flows at higher Reynolds numbers. DA - 2022/10/26/ PY - 2022/10/26/ DO - 10.1017/jfm.2022.612 VL - 950 SP - SN - 1469-7645 KW - separated flows ER - TY - JOUR TI - Study on PN heterojunctions associated bending coupling in flexoelectric semiconductor composites considering the effects of size-dependent and symmetry-breaking AU - Li, Haoqing AU - Chu, Liangliang AU - Li, Yanbin AU - Dui, Guansuo AU - Deng, Qian T2 - JOURNAL OF APPLIED PHYSICS AB - Under bending deformation, size-dependent and structure-associated strain gradients can occur at the interface of a flexoelectric semiconductor (FS) PN heterojunction. Consequentially, a giant flexoelectric coupling will be induced to significantly enhance the flexoelectric effect of FS structures. To better understand the strain gradient–enhanced modulation performance and also reveal some other new phenomena, in this work, we theoretically and numerically study a beam shaped FS laminated composite subjected to pure bending loads. We first establish a one-dimensional theoretical model and then numerically explore the mechanical behaviors of the selected FS beam laminate. During analysis, structural symmetry breaking and size effect are considered by tuning the beam structural size and material parameters. We find that different from piezoelectric semiconductors whose mobile charges are driven by the piezo-potential, the mobile charges of FS composites induced by the flexo-potential are deterministically associated with strain gradients. Moreover, the strain gradients can exhibit a strong size-dependent effect and are quite sensitive to structural asymmetry and material parameters. We believe that our work can provide a new way to tune the carrier transport and electromechanical characteristics of a PN junction and thus can be useful to guide the next-generation flexotronic device designs. DA - 2022/9/28/ PY - 2022/9/28/ DO - 10.1063/5.0102209 VL - 132 IS - 12 SP - SN - 1089-7550 ER - TY - JOUR TI - Amplifying Lamb Wave Detection for Fiber Bragg Grating with a Phononic Crystal GRIN Lens Waveguide AU - Wang, Chia-Fu AU - Wee, Junghyun AU - Peters, Kara T2 - SENSORS AB - This paper demonstrates that a graded-index (GRIN) phononic lens, combined with a channel waveguide, can focus anti-symmetric Lamb waves for extraction by a detector with strong directional sensitivity. Guided ultrasonic wave inspection is commonly applied for structural health monitoring applications; however, obtaining sufficient signal amplitude is a challenge. In addition, fiber Bragg grating (FBG) sensors have strong directional sensitivity. We fabricate the GRIN structure, followed by a channel waveguide starting at the focal point, using a commercial 3D printer and mount it on a thin aluminum plate. We characterize the focusing of the A0 mode Lamb wave in the plate, traveling across the GRIN lens using 3D laser Doppler vibrometry. We also measure the extraction of focused energy using an FBG sensor, examining the optimal sensor bond location and bond length in the channel of the waveguide for maximum signal extraction. The measured amplification of the ultrasound signal is compared to theoretical predictions. The results demonstrate that significant amplification of the waveform is achieved and that selecting the location of the FBG sensor in the channel is critical to optimizing the amplification. DA - 2022/11// PY - 2022/11// DO - 10.3390/s22218426 VL - 22 IS - 21 SP - SN - 1424-8220 UR - https://www.mdpi.com/1424-8220/22/21/8426 KW - structural health monitoring KW - guided wave imaging KW - phononic metamaterials KW - fiber Bragg grating sensors ER - TY - JOUR TI - Experimental Investigations of the Hypersonic Stream-Traced Performance Inlet at Subdesign Mach Number AU - Johnson, Ethan AU - Jenquin, Chase AU - McCready, Jonathan AU - Narayanaswamy, Venkat AU - Edwards, Jack T2 - AIAA JOURNAL AB - Stream-traced inlets offer superior compression efficiency for scramjet engines and are strong prospects for practical application. However, only limited experimental information is available on the subdesign performance of these inlets. In this study, the operation of a stream-traced truncated-Busemann inlet with a design point of Mach 5.5 and a physical contraction ratio of [Formula: see text] is experimentally investigated in a Mach 4.0 flow. Several nonintrusive flow measurement techniques are employed to provide a thorough understanding of the intricate flowfield within these inlets at various operation conditions. The measurements include surface pressure, mean streak-line patterns, off-body velocity fields, and qualitative gas density fields. Together, these datasets provided a unique understanding of the flow evolution and load distribution within the inlet and isolator with and without application of an external backpressure. The facility effects on the inlet operation are also explored. Without appropriate boundary-layer conditioning, the wind-tunnel starting shock could not be swallowed by the inlet; this is termed a “failed start” operation. During the failed start operation the inlet flowfield and surface pressure field, even without external backpressure, exhibited strong similarities with an unstarted inlet. The failed start operation enabled a unique lens to the flowfield in the unstarted inlet throat that could not be otherwise obtained due to optical constraints. DA - 2022/9/30/ PY - 2022/9/30/ DO - 10.2514/1.J062113 VL - 61 IS - 1 SP - SN - 1533-385X ER - TY - JOUR TI - Comparison of High-Speed Polarization Imaging Methods for Biological Tissues AU - Wu, Xianyu AU - Pankow, Mark AU - Onuma, Taka AU - Huang, Hsiao-Ying Shadow AU - Peters, Kara T2 - SENSORS AB - We applied a polarization filter array and high-speed camera to the imaging of biological tissues during large, dynamic deformations at 7000 frames per second. The results are compared to previous measurements of similar specimens using a rotating polarizer imaging system. The polarization filter eliminates motion blur and temporal bias from the reconstructed collagen fiber alignment angle and retardation images. The polarization imaging configuration dose pose additional challenges due to the need for calibration of the polarization filter array for a given sample in the same lighting conditions as during the measurement. DA - 2022/10// PY - 2022/10// DO - 10.3390/s22208000 VL - 22 IS - 20 SP - SN - 1424-8220 UR - https://www.mdpi.com/1424-8220/22/20/8000 KW - high-speed imaging KW - polarization imaging KW - mechanical testing KW - tissue properties ER - TY - JOUR TI - Effects of axon branching and asymmetry between the branches on transport, mean age, and age density distributions of mitochondria in neurons: A computational study AU - Kuznetsov, Ivan A. AU - Kuznetsov, Andrey V T2 - INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING AB - Abstract We report a computational study of mitochondria transport in a branched axon with two branches of different sizes. For comparison, we also investigate mitochondria transport in an axon with symmetric branches and in a straight (unbranched) axon. The interest in understanding mitochondria transport in branched axons is motivated by the large size of arbors of dopaminergic neurons, which die in Parkinson's disease. Since the failure of energy supply of multiple demand sites located in various axonal branches may be a possible reason for the death of these neurons, we were interested in investigating how branching affects mitochondria transport. Besides investigating mitochondria fluxes between the demand sites and mitochondria concentrations, we also studied how the mean age of mitochondria and mitochondria age densities depend on the distance from the soma. We established that if the axon splits into two branches of unequal length, the mean ages of mitochondria and age density distributions in the demand sites are affected by how the mitochondria flux splits at the branching junction (what portion of mitochondria enter the shorter branch and what portion enter the longer branch). However, if the axon splits into two branches of equal length, the mean ages and age densities of mitochondria are independent of how the mitochondria flux splits at the branching junction. This even holds for the case when all mitochondria enter one branch, which is equivalent to a straight axon. Because the mitochondrial membrane potential (which many researchers view as a proxy for mitochondrial health) decreases with mitochondria age, the independence of mitochondria age on whether the axon is symmetrically branched or straight (providing the two axons are of the same length), and on how the mitochondria flux splits at the branching junction, may explain how dopaminergic neurons can sustain very large arbors and still maintain mitochondrial health across branch extremities. DA - 2022/10/8/ PY - 2022/10/8/ DO - 10.1002/cnm.3648 SP - SN - 2040-7947 KW - axonal transport KW - mitochondrial health KW - Parkinson's disease KW - large axonal arbors KW - mathematical modeling ER - TY - JOUR TI - Static and dynamic modeling of steam integration for a NuScale small modular reactor and pulp and paper mill coupling for carbon-neutral manufacturing AU - Worsham, Elizabeth K. AU - Terry, Stephen D. T2 - APPLIED ENERGY AB - Small modular reactors (SMRs) are reactor designs producing less than 300 MWe and are generally planned for deployment as multimodule nuclear power plants. The possibility of factory-manufactured, flexibly sized plants expands the opportunities for nuclear power to different communities and industries, including manufacturing plants that currently utilize fossil fuels to produce both steam and electricity. This paper examines the feasibility of coupling a NuScale SMR with a midsize pulp and paper mill in the Southeastern United States. A steady-state mill model was developed in Aspen HYSYS, based on real data from the operation of the mill, and modified it to include the SMR while maintaining steam quality requirements and making as few changes as possible to existing equipment. Dynamic plant models were also developed Dymola to demonstrate possible plant conditions, using three configurations. Preliminary results suggest that, while SMR coupling is physically feasible, its economic feasibility is limited by the differences in steam and electricity demands. Because of limitations in the amount of steam the mill can take from the SMR, sizing the SMR for the plant’s steam demand may result in an electricity deficit, or vice versa. Dynamic analyses show that the addition of a thermal storage system could reduce such deficits, but this entails its own challenges. Each plant must determine the best configuration and control scheme for itself, based on its electricity and heat needs, including the peak duration and intensity for both. Ultimately, an implementation of SMRs with manufacturing processes would benefit from partnering with a local utility to purchase excess electricity generated by the SMR. This will help manufacturing facilities meet their environmental and cost-savings goals, in addition to meeting the need for cost-effective baseload power across the United States. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.1016/j.apenergy.2022.119613 VL - 325 SP - SN - 1872-9118 ER - TY - JOUR TI - Computation of the mitochondrial age distribution along the axon length AU - Kuznetsov, Ivan A. AU - Kuznetsov, Andrey V T2 - COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING AB - We describe a compartmental model of mitochondrial transport in axons, which we apply to compute mitochondrial age at different distances from the soma. The model predicts that at the tip of an axon that has a length of 1 cm, the average mitochondrial age is approximately 22 h. The mitochondria are youngest closest to the soma and their age scales approximately linearly with distance from the soma. To the best of the authors’ knowledge, this is the first attempt to predict the spatial distribution of mitochondrial age within an axon. A sensitivity study of the mean age of mitochondria to various model parameters is also presented. DA - 2022/9/27/ PY - 2022/9/27/ DO - 10.1080/10255842.2022.2128784 SP - SN - 1476-8259 KW - Neurons KW - axonal transport KW - organelles KW - mean age KW - mathematical modeling ER - TY - JOUR TI - CFD multiphase combustion modelling of oleic by-products pellets in a counter-current fixed bed combustor AU - Mami, Mohamed Ali AU - Lajili, Marzouk AU - Echekki, Tarek T2 - COMPTES RENDUS CHIMIE AB - A transient two-dimensional multiphase model was built to study the combustion of pellets of oleic by-products (Olive Pits (OPi)) in a cylindrical counter-current 40 kW fixed bed combustor. The fixed bed is modelled as a porous medium, which is randomly packed with spherical particles of equal size. A κ-ε model for low Reynolds number flows was used for turbulence Modelling. Primary and secondary air injections were supplied at the bed (solid phase combustion) and at the freeboard zone (gas phase combustion), respectively. The mass loss history, the temperature distribution at different heights inside the reactor and the gas emissions of CO, CO 2 , O 2 , H 2 , CH 4 and C org were computed. Key parameters related to the reaction front velocity, the mass conversion rate and the progress of ignition were also computed. We show that computational results are in good agreement with experimental measurements obtained using a similar reactor fed with the same pellet types. These results also motivate the implementation of the present formulation and its extension to industrial scale furnaces, having established the results for the comparison with pilot-scale experiments. DA - 2022/// PY - 2022/// DO - 10.5802/crchim.170 VL - 25 SP - 113-127 SN - 1878-1543 KW - CFD KW - Porous medium KW - Fixed bed reactor KW - Olive pits pellets KW - Multiphase combustion ER - TY - JOUR TI - Thermal Transport across Polyethylene Chains AU - Yang, Cong AU - Duan, Xuhui AU - Zhou, Jun AU - Liu, Jun AU - Li, Xiaobo T2 - Journal of Thermal Science DA - 2022/7// PY - 2022/7// DO - 10.1007/s11630-022-1640-7 VL - 31 IS - 4 SP - 1061-1067 UR - http://dx.doi.org/10.1007/s11630-022-1640-7 KW - phonon transport KW - polymer KW - polyethylene KW - thermal resistance KW - van der Waals interaction ER - TY - JOUR TI - Enhancement of thermal percolation in composites: A two-dimensional case study AU - Zhong, Jinxin AU - Xi, Qing AU - Jin, Hongjie AU - Wang, Ziqi AU - Ma, Dengke AU - Liu, Jun AU - Zhou, Jun T2 - APPLIED PHYSICS LETTERS AB - We investigated the thermal conductivity (TC) of a two-dimensional composite consisting of matrices with low TC and nanowire fillers with high TC using the Monte Carlo method and the finite element method. Compared to the electrical percolation that requires direct contact between fillers, an additional thermal transport channel through non-contact fillers is found to be important for the thermal percolation in composites. This additional channel can lead to an effective expansion of thermal percolation network by including extra fillers into the network. Thus, it can be utilized to enhance the TC of the composite that is helpful to improve the performance of thermal interface materials. DA - 2022/10/17/ PY - 2022/10/17/ DO - 10.1063/5.0093038 VL - 121 IS - 16 SP - SN - 1077-3118 UR - https://doi.org/10.1063/5.0093038 ER - TY - JOUR TI - Phase estimation via riesz transform in laser speckle interferometry for large-area damage imaging AU - Fong, Rey-Yie AU - Yuan, Fuh-Gwo T2 - NDT & E INTERNATIONAL AB - A direct phase estimation (DPE) via Riesz transform from a speckle pattern (images) for visualizing barely visible impact damage (BVID) occurring in layered composites is proposed in this paper. Rather than complex optical hardware setup for phase extraction in commercial digital speckle pattern interferometry (DSPI) or shearography (SG) systems, the proposed numerical (software) DPE implementation via Riesz transform with a log-Gabor filter enables a compact, portable, and cost-effective system for large-area real-time nondestructive inspection (NDI) due to its simplicity, stability, and efficiency. Using speckles in laser speckle interferometry (LSI) speckle pattern is intrinsically noisy; the correlation-based phase signatures derived from Riesz transform followed by the log-Gabor filter is implemented to supplant the conventional phase-difference algorithm to localize damage regions, especially in the case where the high-power diode laser (low coherence) can cause serious phase drift. By enveloping the monogenic signal through Riesz transform for direct phase retrieval is more intuitive than TPS or SPS. This yields visualization of the damage feature with higher fidelity. Consequently, a phase-correlation algorithm becomes a more robust operation to cope with speckle images from the interferometry. This full-field optical SG system was demonstrated and verified in an impacted damaged honeycomb composite panel using the proposed phase-correlation algorithm under thermal stress loading for large-area inspection in near real-time. The visualized damage images enhanced by principal component analysis (PCA) agreed with images from pulse laser/LDV and X-ray CT scan. The DPE algorithm has a promising potential to apply on any optical metrology for instantaneous phase estimation and can combine with selected imaging conditions for multi-damage detection. DA - 2022/12// PY - 2022/12// DO - 10.1016/j.ndteint.2022.102711 VL - 132 SP - SN - 1879-1174 UR - https://doi.org/10.1016/j.ndteint.2022.102711 KW - Riesz transform KW - Log-gabor bandpass (bp) filter KW - Direct phase estimation (DPE) KW - Shearography (SG) KW - Barely visible impact damage (BVID) ER - TY - JOUR TI - Ballistic loading and survivability of optical fiber sensing layers for soft body armor evaluation AU - Hodges, Greyson AU - Noevere, Alexander AU - Velasco, Ivann AU - Hackney, Drew AU - Seng, Frederick AU - Schultz, Stephen AU - Peters, Kara AU - Pankow, Mark T2 - OPTICAL FIBER TECHNOLOGY AB - • To survive impact the contact radius between the fiber and impactor must be increased. • Silicone was chosen due to its high strain to failure and elastic properties. • In situ silicone sensors have shown to minimally effect back face deformation depth. • Silicone sensing mats are able to protect optical fibers during impact. The authors previously demonstrated the use of FBG sensors in Kevlar mats behind body armor to measure the transient back face deformation (BFD) during ballistic testing. This paper presents a novel sensor system based on a Fiber Bragg Grating embedded in silicone mats to improve the survivability of the body armor in-situ strain sensing layers. Due to the large amount of deformation, a relative slip between the optical fibers and the supporting structure is needed to maintain the performance of the sensors and determine the relationship between the measured strain and deformation shape. Two silicone materials were tested, Smooth-Sil 950 and Sorta-Clear 40, in both 1 mm and 2 mm thicknesses to evaluate their survivability and impact on BFD. To enhance slipping between the fibers and surrounding silicone a thin layer of petroleum jelly was placed on the fibers prior to being cast in the silicone mats. The 1 mm Sorta-Clear 40 mats performed best in silicone survivability, FBG survivability and minimal impact on the BFD. The new system improves on key deficiencies that were found from inserting the fibers directly into the Kevlar with minimal to no impact on the back face deformation. DA - 2022/10// PY - 2022/10// DO - 10.1016/j.yofte.2022.103043 VL - 73 SP - SN - 1095-9912 KW - Fiber Bragg Grating KW - Back Face Deformation KW - Kevlar KW - Ballistic Impact ER - TY - JOUR TI - Next-Generation Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Source for Mass Spectrometry Imaging and High-Throughput Screening AU - Knizner, Kevan T. AU - Guymon, Jacob P. AU - Garrard, Kenneth P. AU - Bouvree, Guy AU - Manni, Jeffrey AU - Hauschild, Jan-Peter AU - Strupat, Kerstin AU - Fort, Kyle L. AU - Earley, Lee AU - Wouters, Eloy R. AU - Pu, Fan AU - Radosevich, Andrew J. AU - Elsen, Nathaniel L. AU - Williams, Jon D. AU - Pankow, Mark R. AU - Muddiman, David C. T2 - JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY AB - Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is a hybrid, ambient ionization source that combines the advantages of electrospray ionization and matrix-assisted laser desorption/ionization, making it a versatile tool for both high-throughput screening (HTS) and mass spectrometry imaging (MSI) studies. To expand the capabilities of the IR-MALDESI source, an entirely new architecture was designed to overcome the key limitations of the previous source. This next-generation (NextGen) IR-MALDESI source features a vertically mounted IR-laser, a planar translation stage with computerized sample height control, an aluminum enclosure, and a novel mass spectrometer interface plate. The NextGen IR-MALDESI source has improved user-friendliness, improved overall versatility, and can be coupled to numerous Orbitrap mass spectrometers to accommodate more research laboratories. In this work, we highlight the benefits of the NextGen IR-MALDESI source as an improved platform for MSI and direct analysis. We also optimize the NextGen MALDESI source component geometries to increase target ion abundances over a wide m/z range. Finally, documentation is provided for each NextGen IR-MALDESI part so that it can be replicated and incorporated into any lab space. DA - 2022/9/29/ PY - 2022/9/29/ DO - 10.1021/jasms.2c00178 VL - 9 SP - SN - 1879-1123 KW - IR-MALDESI KW - High-Throughput Screening KW - Mass Spectrometry Imaging KW - Orbitrap Mass Spectrometer KW - Design of Experiments ER - TY - JOUR TI - Cavity Engineering of Perovskite Distributed Feedback Lasers AU - Dong, Qi AU - Fu, Xiangyu AU - Seyitliyev, Dovletgeldi AU - Darabi, Kasra AU - Mendes, Juliana AU - Lei, Lei AU - Chen, Yi-An AU - Chang, Chih-Hao AU - Amassian, Aram AU - Gundogdu, Kenan AU - So, Franky T2 - ACS PHOTONICS DA - 2022/8/18/ PY - 2022/8/18/ DO - 10.1021/acsphotonics.2c00917 SP - SN - 2330-4022 KW - perovskite lasers KW - distributed feedback lasers KW - cavity fabrication KW - cavity engineering ER - TY - JOUR TI - An Analytic Solution to the Inverse Dynamics of an Energy Harvesting Tethered Kite AU - Bhattacharjee, Debapriya AU - Tiburcio, Miguel Alvarez AU - Opila, Daniel F. AU - Vermillion, Christopher AU - Fathy, Hosam K. T2 - JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME AB - Abstract This paper solves the inverse dynamics of a tethered kite analytically. Specifically, the paper presents a procedure for determining the angle of attack, induced roll angle, and tether tension magnitude needed to achieve a desired combination of translational kite position, velocity, and acceleration. The focus of the paper is on energy harvesting kites. However, the underlying approach is applicable to other kite systems, such as kites for propulsion (e.g., SkySails, Hamburg, Germany). Solving inverse kite dynamics analytically is valuable for trajectory optimization, online state estimation, and the analysis of fundamental limitations on kite maneuvers. Previous work in the literature presents several models of kite dynamics, with varying degrees of fidelity and complexity. However, the nonlinearity of these models often makes them difficult to use for optimization, estimation, and control. The paper shows that, under reasonable assumptions, inverse kite dynamics can be solved in terms of the roots of a fourth-order polynomial function of angle of attack. This function has a geometric interpretation, providing insight into the multiplicity of resulting solutions. Moreover, for special cases including a kite with noncambered wings, these solutions can be computed analytically. A simulation validates the success of the proposed approach in computing inverse kite dynamics for a cross-current trajectory. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.1115/1.4055169 VL - 144 IS - 11 SP - SN - 1528-9028 ER - TY - JOUR TI - Temporal evolution of the behavior of absorbed moisture in a damaged polymer-quartz composite: A molecular dynamics study AU - Guha, Rishabh D. AU - Rahmani, Farzin AU - Berkowitz, Katherine AU - Pasquinelli, Melissa AU - Grace, Landon R. T2 - COMPUTATIONAL MATERIALS SCIENCE AB - • Interfacial Debonding was simulated on a nanoscale using an atomistic model of a quartz-fiber composite. • The temporal behavior of absorbed moisture was analyzed near the damage site. • Irrespective of the initial state of moisture in the composite, they eventually agglomerate near the damage location. • Spatial confinement near the interface bolsters previous experiments which hypothesize that absorbed moisture behaves like bulk water when clustered at microcracks. Exposure of a composite structure to mechanical or environmental stressors often leads to the formation of damage sites which contain rupture mechanisms such as matrix cracking and interfacial debonding. Continued accumulation of this type of small-scale damage can cause sudden and catastrophic large-scale failure. A novel damage characterization technique which leverages the altered physical and chemical states of naturally absorbed moisture in response to sub-micron scale damage has recently shown promise for early detection of damage. In this work, molecular dynamics simulations are used to better understand the differences in the behavior of absorbed water molecules near a damage site. The results show that, irrespective of the initial distribution of molecular water throughout the composite, or the presence of polar atoms in the polymer matrix, water tends to preferentially cluster near the damage location. It was also found that spatial confinement near the polymer-fiber interface hinders diffusion of the water molecules into the polymer matrix. These molecular level insights bolster the hypothesis formulated in previous experimental studies that absorbed moisture behaves like free water in terms of its dielectric activity when the water molecules agglomerate at the damage location. Consequently, this locally distinct permittivity can be leveraged for damage detection and quantification. DA - 2022/11// PY - 2022/11// DO - 10.1016/j.commatsci.2022.111690 VL - 214 SP - SN - 1879-0801 KW - Composites KW - Fiber -matrix interface KW - Moisture KW - Debonding KW - Molecular dynamics ER - TY - JOUR TI - Mechanical characterization of piezoelectric materials: A perspective on deformation behavior across different microstructural length scales AU - Kathavate, V. S. AU - Prasad, K. Eswar AU - Kiran, Mangalampalli S. R. N. AU - Zhu, Yong T2 - JOURNAL OF APPLIED PHYSICS AB - Piezoelectric materials (PEMs) find a wide spectrum of applications that include, but are not limited to, sensors, actuators, semiconductors, memory devices, and energy harvesting systems due to their outstanding electromechanical and polarization characteristics. Notably, these PEMs can be employed across several length scales (both intrinsic and extrinsic) ranging from mesoscale (bulk ceramics) to nanoscale (thin films) during their applications. Over the years, progress in probing individual electrical and mechanical properties of PEM has been notable. However, proportional review articles providing the mechanical characterization of PEM are relatively few. The present article aims to give a tutorial on the mechanical testing of PEMs, ranging from the conventional bulk deformation experiments to the most recent small-scale testing techniques from a materials science perspective. The advent of nanotechnology has led materials scientists to develop in situ testing techniques to probe the real-time electromechanical behavior of PEMs. Therefore, this article presents a systematic outlook on ex situ and in situ deformation experiments in mechanical and electromechanical environments, related mechanical behavior, and ferroelectric/elastic distortion during deformation. The first part provides significant insights into the multifunctionality of PEM and various contributing microstructural length scales, followed by a motivation to characterize the mechanical properties from the application's point of view. In the midst, the mechanical behavior of PEM and related mechanical characterization techniques (from mesoscale to nanoscale) are highlighted. The last part summarizes current challenges, future perspectives, and important observations. DA - 2022/9/28/ PY - 2022/9/28/ DO - 10.1063/5.0099161 VL - 132 IS - 12 SP - SN - 1089-7550 ER - TY - JOUR TI - Evaluation of Muscle Synergy During Exoskeleton-Assisted Walking in Persons With Multiple Sclerosis AU - Afzal, Taimoor AU - Zhu, Fangshi AU - Tseng, Shih-Chiao AU - Lincoln, John A. AU - Francisco, Gerard E. AU - Su, Hao AU - Chang, Shuo-Hsiu T2 - IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING AB - Gait deficit after multiple sclerosis (MS) can be characterized by altered muscle activation patterns. There is preliminary evidence of improved walking with a lower limb exoskeleton in persons with MS. However, the effects of exoskeleton-assisted walking on neuromuscular modifications are relatively unclear. The objective of this study was to investigate the muscle synergies, their activation patterns and the differences in neural strategies during walking with (EXO) and without (No-EXO) an exoskeleton.Ten subjects with MS performed walking during EXO and No-EXO conditions. Electromyography signals from seven leg muscles were recorded. Muscle synergies and the activation profiles were extracted using non-negative matrix factorization.The stance phase duration was significantly shorter during EXO compared to the No-EXO condition (p<0.05). Moreover, typically 3-5 modules were extracted in each condition. The module-1 (comprising Vastus Medialis and Rectus Femoris muscles), module-2 (comprising Soleus and Medial Gastrocnemius muscles), module-3 (Tibialis Anterior muscle) and module-4 (comprising Biceps Femoris and Semitendinosus muscles) were comparable between conditions. During EXO condition, Semitendinosus and Vastus Medialis emerged in module-5 in 7/10 subjects. Compared to No-EXO, average activation amplitude was significantly reduced corresponding to module-2 during the stance phase and module-3 during the swing phase during EXO.Exoskeleton-assistance does not alter the existing synergy modules, but could induce a new module to emerge, and alters the control of these modules, i.e., modifies the neural commands indicated by the reduced amplitude of the activation profiles.The work provides insights on the potential underlying mechanism of improving gait functions after exoskeleton-assisted locomotor training. DA - 2022/10// PY - 2022/10// DO - 10.1109/TBME.2022.3166705 VL - 69 IS - 10 SP - 3265-3274 SN - 1558-2531 KW - Muscles KW - Legged locomotion KW - Exoskeletons KW - Multiple sclerosis KW - Training KW - Turning KW - Knee KW - Exoskeletons KW - multiple sclerosis KW - gait KW - muscle synergy ER - TY - JOUR TI - Digital Synthesis of Realistically Clustered Carbon Nanotubes AU - Susi, Bryan T. AU - Tu, Jay F. T2 - C-JOURNAL OF CARBON RESEARCH AB - A computational approach for creating realistically structured carbon nanotubes is presented to enable more accurate and impactful multi-scale modeling and simulation techniques for nanotube research. Much of the published literature to date involving computational modeling of carbon nanotubes simplifies their structure as being long and straight, and often existing as isolated individual nanotubes. However, imagery of nanotubes has shown over several decades that nanotubes agglomerate together and exhibit looping and curvature due both to inter- and intra-nanotube attraction. The research presented in this paper leverages multi-scale simulations consisting of a simple bead-spring model for initial nanotube relaxation followed by a differential geometry approach to create an atomic representation of carbon nanotubes, and then finalized with molecular dynamics simulations using the Tersoff potential model for carbon that allows dynamic bonding and cleavage. The result is atomically accurate representations of carbon nanotubes that exist as single nanotubes, or as clusters of multiple nanotubes. The presented approach is demonstrated using (5,5) single-walled carbon nanotubes. The synthesized nanotubes are shown to relax into the curving and looping structures observed in transmission or scanning electron microscopy, but also exhibit nano-scale defects due to buckling, crimping, and twisting that are resolved during the molecular dynamics simulations. These features locally compromise the desired strength characteristics of nanotubes and therefore the presented procedure will enable more accurate modeling and simulation of nanotubes in subsequent research by representing them less as the theoretically straight and independent entities, but as realistically imperfect. DA - 2022/9// PY - 2022/9// DO - 10.3390/c8030034 VL - 8 IS - 3 SP - SN - 2311-5629 KW - carbon nanotubes KW - Tersoff KW - molecular dynamics KW - clusters KW - digital synthesis ER - TY - JOUR TI - Optical diagnostics of misfire in partially premixed combustion under low load conditions AU - Cui, Yanqing AU - Liu, Haifeng AU - Wen, Mingsheng AU - Feng, Lei AU - Ming, Zhenyang AU - Zheng, Zunqing AU - Fang, Tiegang AU - Xu, Leilei AU - Bai, Xue-Song AU - Yao, Mingfa T2 - FUEL AB - • Fuel-tracer PLIF is used to quantify the equivalence ratio and temperature. • Misfire of PPC is due to synergistic effect of equivalent ratio and temperature. • In high direct injection pressure, the misfire is due to excessive premixing. • In late direct injection timing, the misfire is due to thermodynamic environment. • Misfire region most likely appears when the equivalence ratio is lower than 0.49. To clarify the misfire mechanism is important for stabilizing combustion in partially premixed combustion (PPC) under low load. Fuel-tracer planar laser-induced fluorescence (PLIF), formaldehyde PLIF, flame and OH* natural luminosity imaging were utilized to qualify the local equivalence ratio, low-temperature reaction and the high-temperature flame features in an optical engine. Results show that in high direct injection (DI) pressure (1000 bar), due to excessive premixing, the local equivalence ratio in the initial timing of the high temperature heat release (HTHR) is low. Although the auto-ignition flame kernels are formed in high DI pressure, they cannot stably develop, resulting in misfire during the flame development process. In late DI timing (-5 crank angle degree after top dead center, °CA ADTC), since the whole heat release process occurs in the expansion stroke, the in-cylinder temperature and pressure continue decreasing. Although the local equivalence ratio in some regions is high enough, the in-cylinder thermodynamic environment does not support the generation of more auto-ignition flame kernels, thus a small amount of auto-ignition flame kernels can only develop through flame propagation. In short, the misfire of PPC occurs in regions where the equivalence ratio is low or the in-cylinder thermodynamic environment does not further support flame development. Therefore, the trade-off relationship between equivalence ratio and temperature determines the formation of auto-ignition kernels. The local equivalence ratio and temperature distribution near the initial timing of HTHR is the key factor to ensure the subsequent stable combustion. Taking the ambient pressure of 18 bar as an example, the boundary condition where the autoignition kernels are most likely formed or the charge is most likely ignited by the nearby flame kernels is in the range of 0.53–0.62 for equivalence ratio and 740–757 K for temperature. The misfire region most likely appears when the equivalence ratio is lower than 0.49. It can be concluded that the misfire of PPC results from the synergistic effect of local equivalent ratio and temperature. The controlling parameters of injection pressure and injection timing are actually optimizing the suitable combinations of equivalence ratio and temperature to stabilize combustion. DA - 2022/12/1/ PY - 2022/12/1/ DO - 10.1016/j.fuel.2022.125432 VL - 329 SP - SN - 1873-7153 KW - Partially premixed combustion (PPC) KW - Misfire KW - Planar laser -induced fluorescence (PLIF) KW - Quantitative measurement of equivalence ratio KW - and temperature ER - TY - JOUR TI - Special Issue "Functionalities of Polymer-Based Nanocomposite Films and Coatings" AU - Yang, Ni T2 - COATINGS AB - Polymer-based coatings are the thin film of polymer applied to any type of flat or irregular surfaces (e [...] DA - 2022/9// PY - 2022/9// DO - 10.3390/coatings12091245 VL - 12 IS - 9 SP - SN - 2079-6412 ER - TY - JOUR TI - A Wearable Electrocardiography Armband Resilient Against Artifacts AU - Zhou, Yilu AU - Mohaddes, Farzad AU - Lee, Courtney AU - Rao, Smriti AU - Mills, Amanda C. AU - Curry, Adam C. AU - Lee, Bongmook AU - Misra, Veena T2 - IEEE SENSORS JOURNAL AB - Electrocardiography (ECG) is an essential technique to assess cardiovascular conditions and monitor physical activities. While the concept is mature, issues surrounding sampling convenience and device adoption as well as maintaining signal quality under artifacts remain a problem. In this article, we present a high-performing wearable ECG armband on the upper left arm. It is equipped with miniaturized hardware, capable of data storage and wireless communication. We evaluate different electrode configurations by conducting ECG measurements both at the static state and under motion and using improved algorithms to quantify data quality and assess the agreement between the proposed new technique and the gold standard. The optimal electrode position is determined by balancing wearable suitability and signal quality. We propose an electronic textile (E-textile) armband with improved design. It offers favorable wearing comfort and a fashionable appearance without sacrificing data quality. Its contact pressure is measured to get a better picture of intimacy and clothing comfort. Our system provides real-time and noise-resilient ECG data without interrupting daily life and can be implemented in use cases that warrant continuous ECG monitoring. DA - 2022/10/1/ PY - 2022/10/1/ DO - 10.1109/JSEN.2022.3197060 VL - 22 IS - 19 SP - 18970-18977 SN - 1558-1748 UR - https://doi.org/10.1109/JSEN.2022.3197060 KW - Biomedical monitoring KW - body sensor KW - electrocardiography (ECG) KW - electrodes KW - electronic textiles (E-textiles) KW - sensors KW - wearable sensor ER - TY - JOUR TI - A vascularized model of the human liver mimics regenerative responses AU - Chhabra, Arnav AU - Song, H-H Greco AU - Grzelak, Katarzyna A. AU - Polacheck, William J. AU - Fleming, Heather E. AU - Chen, Christopher S. AU - Bhatia, Sangeeta N. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Liver regeneration is a well-orchestrated process that is typically studied in animal models. Although previous animal studies have offered many insights into liver regeneration, human biology is less well understood. To this end, we developed a three-dimensional (3D) platform called structurally vascularized hepatic ensembles for analyzing regeneration (SHEAR) to model multiple aspects of human liver regeneration. SHEAR enables control over hemodynamic alterations to mimic those that occur during liver injury and regeneration and supports the administration of biochemical inputs such as cytokines and paracrine interactions with endothelial cells. We found that exposing the endothelium-lined channel to fluid flow led to increased secretion of regeneration-associated factors. Stimulation with relevant cytokines not only amplified the secretory response, but also induced cell-cycle entry of primary human hepatocytes (PHHs) embedded within the device. Further, we identified endothelial-derived mediators that are sufficient to initiate proliferation of PHHs in this context. Collectively, the data presented here underscore the importance of multicellular models that can recapitulate high-level tissue functions and demonstrate that the SHEAR device can be used to discover and validate conditions that promote human liver regeneration. DA - 2022/7/12/ PY - 2022/7/12/ DO - 10.1073/pnas.2115867119 VL - 119 IS - 28 SP - SN - 1091-6490 KW - hepatocyte KW - regeneration KW - vascular ER - TY - JOUR TI - Developing transmission mode for infrared matrix-assisted laser desorption electrospray ionization mass spectrometry imaging AU - Joignant, Alena N. AU - Bai, Hongxia AU - Guymon, Jacob P. AU - Garrard, Kenneth P. AU - Pankow, Mark AU - Muddiman, David C. T2 - RAPID COMMUNICATIONS IN MASS SPECTROMETRY AB - The development and characterization of the novel NextGen infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source catalyzed new advancements in IR-MALDESI instrumentation, including the development of a new analysis geometry.A vertically oriented transmission mode (tm)-IR-MALDESI setup was developed and optimized on thawed mouse tissue. In addition, glycerol was introduced as an alternative energy-absorbing matrix for tm-IR-MALDESI because the new geometry does not currently allow for the formation of an ice matrix. The tm geom was evaluated against the optimized standard geometry for the NextGen source in reflection mode (rm).It was found that tm-IR-MALDESI produces comparable results to rm-IR-MALDESI after optimization. The attempt to incorporate glycerol as an alternative matrix provided little improvement to tm-IR-MALDESI ion abundances.This work has successfully demonstrated the adaptation of the NextGen IR-MALDESI source through the feasibility of tm-IR-MALDESI mass spectrometry imaging on mammalian tissue, expanding future biological applications of the method. DA - 2022/11/30/ PY - 2022/11/30/ DO - 10.1002/rcm.9386 VL - 36 IS - 22 SP - SN - 1097-0231 ER - TY - JOUR TI - Analysis of an Elasto-Hydrodynamic Seal by Using the Reynolds Equation AU - Cesmeci, Sevki AU - Lyathakula, Karthik Reddy AU - Hassan, Mohammad Fuad AU - Liu, Shuangbiao AU - Xu, Hanping AU - Tang, Jing T2 - APPLIED SCIENCES-BASEL AB - This paper reports numerical studies of an Elasto-Hydrodynamic (EHD) seal, which is being developed for supercritical CO2 (sCO2) turbomachinery applications. Current sCO2 turbomachinery suffers from high leakage rates, which is creating a major roadblock to the full realization of sCO2 power technology. The high leakage rates not only penalize the efficiencies but also create environmental concerns due to greenhouse effects caused by the increased CO2 discharge to the atmosphere. The proposed EHD seal needs to work at elevated pressures (10–35 MPa) and temperatures (350–700 °C) with low leakage and minimal wear. The unique mechanism of the EHD seal provides a self-regulated constriction effect to restrict the flow without substantial material contact, thereby minimizing leakage and wear. This work utilizes a physics-based modeling approach. The flow through the gradually narrowing seal clearance is modeled by the well-known Reynolds equation in EHD lubrication theory, while the deformation of the seal is modeled by using the governing equations of three-dimensional solid mechanics. As for the solution methodology, COMSOL’s Thin-Film Flow and Solid Mechanics modules were employed with their powerful capabilities. The numerical results were presented and discussed. It was observed that the Reynolds equation fully coupled with the surface deformation was able to successfully capture the constriction effect. The maximum and minimum leakages were calculated to be 2.25 g/s and 0.1 g/s at P = 5.5 MPa and P = 11 MPa for the design seal, respectively. It was interesting to observe that the seal leakage followed a quadratic trend with increasing pressure differential, which can become advantageous for high-pressure applications such as sCO2 power generation technology. DA - 2022/10// PY - 2022/10// DO - 10.3390/app12199501 VL - 12 IS - 19 SP - SN - 2076-3417 UR - https://doi.org/10.3390/app12199501 KW - elasto-hydrodynamic KW - EHD KW - power KW - Reynolds equation KW - seal KW - supercritical KW - sCO(2) ER - TY - JOUR TI - Physics-based deep neural network model to guide electrospinning polyurethane fibers AU - Rahman, S. Mashfiqur AU - Tafreshi, Hooman Vahedi AU - Pourdeyhimi, Behnam T2 - JOURNAL OF APPLIED POLYMER SCIENCE AB - Abstract Electrospinning is an inexpensive room‐temperature method of producing nanofibers from polymer granules. While it is quite easy to produce electrospun nanofibers, it is very difficult to control properties of the resulting fibers without conducting laborious trial‐and‐error experiments. In this work, a mass‐spring‐damper (MSD) model was used to simulate formation of electrospun fibers for different combinations of electrospinning conditions such as voltage, needle‐to‐collector distance, and polymer concentration. The sparse data from the CPU‐intensive MSD model were then used in developing a deep neural network (DNN) model that could guide the electrospinning experiment toward producing fibers with a desired diameter. The accuracy of the MSD‐DNN hybrid model was examined via comparison with experimental data obtained by electrospinning polyurethane fibers. DA - 2022/9/20/ PY - 2022/9/20/ DO - 10.1002/app.53108 VL - 9 SP - SN - 1097-4628 UR - https://doi.org/10.1002/app.53108 KW - coatings KW - fibers KW - membranes KW - porous materials ER - TY - JOUR TI - Highly electromagnetic transparent ceramic composite made of boron nitride nanotubes and silicon oxynitride via perhydropolysilazane infiltration method AU - Yang, Ni AU - Xu, Shaofan AU - Xu, Chengying T2 - SCIENTIFIC REPORTS AB - With the rapid development of electromagnetic (EM) wave circuit devices, high-performance wave-transparent materials with various functions have attracted great attention. Ceramic material is a promising candidate to be applied in harsh environments because of its chemical and corrosion resistance. In this work, a polymer-derived route was adopted to synthesize ceramic composite at room temperature. The composite is made of perhydropolysilazane-derived SiON ceramic and reinforced with boron nitride nanotubes (BNNTs) sheets. With the addition of SiON ceramic materials, the resultant sample showed an excellent hydrophobicity with a contact angle of 135-146.9°. More importantly, superior thermal stability at 1600 °C in the oxygen-containing atmosphere was observed for the fabricated SiON/BNNTs sample, without any shape change. The electromagnetic transparency of the SiON/BNNTs was studied through the waveguide method. The prepared SiON/BNNTs sample has an average real permittivity between 1.52 and 1.55 and an average loss tangent value in the range of 0.0074-0.0266, at the frequency range of 26.5-40 GHz. The effect of thickness on the wave transparency of SiON/BNNTs samples is also discussed. To summarize the aforementioned superior characterization and measurement results, the presented SiON/BNNTs material system has a great potential to be used as EM transparent materials in harsh conditions. DA - 2022/8/23/ PY - 2022/8/23/ DO - 10.1038/s41598-022-18563-4 VL - 12 IS - 1 SP - SN - 2045-2322 ER - TY - JOUR TI - On-demand, remote and lossless manipulation of biofluid droplets AU - Wang, Wei AU - Sun, Jiefeng AU - Vallabhuneni, Sravanthi AU - Pawlowski, Benjamin AU - Vahabi, Hamed AU - Nellenbach, Kimberly AU - Brown, Ashley C. AU - Scholle, Frank AU - Zhao, Jianguo AU - Kota, Arun K. T2 - MATERIALS HORIZONS AB - To minimize exposure of healthcare workers and clinical laboratory personnel to infectious liquids, we designed biofluid manipulators for on-demand handling of liquid droplets, in-plane or out-of-plane, in a remote and lossless manner. DA - 2022/9/7/ PY - 2022/9/7/ DO - 10.1039/d2mh00695b SP - SN - 2051-6355 ER - TY - JOUR TI - Sensor Fusion with Deep Learning for Autonomous Classification and Management of Aquatic Invasive Plant Species AU - Perrin, Jackson E. AU - Jernigan, Shaphan R. AU - Thayer, Jacob D. AU - Howell, Andrew W. AU - Leary, James K. AU - Buckner, Gregory D. T2 - ROBOTICS AB - Recent advances in deep learning, including the development of AlexNet, Residual Network (ResNet), and transfer learning, offer unprecedented classification accuracy in the field of machine vision. A developing application of deep learning is the automated identification and management of aquatic invasive plants. Classification of submersed aquatic vegetation (SAV) presents a unique challenge, namely, the lack of a single source of sensor data that can produce robust, interpretable images across a variable range of depth, turbidity, and lighting conditions. This paper focuses on the development of a multi-sensor (RGB and hydroacoustic) classification system for SAV that is robust to environmental conditions and combines the strengths of each sensing modality. The detection of invasive Hydrilla verticillata (hydrilla) is the primary goal. Over 5000 aerial RGB and hydroacoustic images were generated from two Florida lakes via an unmanned aerial vehicle and boat-mounted sonar unit, and tagged for neural network training and evaluation. Classes included “HYDR”, containing hydrilla; “NONE”, lacking SAV, and “OTHER”, containing SAV other than hydrilla. Using a transfer learning approach, deep neural networks with the ResNet architecture were individually trained on the RGB and hydroacoustic datasets. Multiple data fusion methodologies were evaluated to ensemble the outputs of these neural networks for optimal classification accuracy. A method incorporating logic and a Monte Carlo dropout approach yielded the best overall classification accuracy (84%), with recall and precision of 84.5% and 77.5%, respectively, for the hydrilla class. The training and ensembling approaches were repeated for a DenseNet model with identical training and testing datasets. The overall classification accuracy was similar between the ResNet and DenseNet models when averaged across all approaches (1.9% higher accuracy for the ResNet vs. the DenseNet). DA - 2022/8// PY - 2022/8// DO - 10.3390/robotics11040068 VL - 11 IS - 4 SP - SN - 2218-6581 KW - aquatic invasive plants KW - deep learning KW - sensor fusion KW - autonomous robotics ER - TY - JOUR TI - Surface Wrinkling for Flexible and Stretchable Sensors AU - Lee, Giwon AU - Zarei, Mohammad AU - Wei, Qingshan AU - Zhu, Yong AU - Lee, Seung Goo T2 - SMALL AB - Recent advances in nanolithography, miniaturization, and material science, along with developments in wearable electronics, are pushing the frontiers of sensor technology into the large-scale fabrication of highly sensitive, flexible, stretchable, and multimodal detection systems. Various strategies, including surface engineering, have been developed to control the electrical and mechanical characteristics of sensors. In particular, surface wrinkling provides an effective alternative for improving both the sensing performance and mechanical deformability of flexible and stretchable sensors by releasing interfacial stress, preventing electrical failure, and enlarging surface areas. In this study, recent developments in the fabrication strategies of wrinkling structures for sensor applications are discussed. The fundamental mechanics, geometry control strategies, and various fabricating methods for wrinkling patterns are summarized. Furthermore, the current state of wrinkling approaches and their impacts on the development of various types of sensors, including strain, pressure, temperature, chemical, photodetectors, and multimodal sensors, are reviewed. Finally, existing wrinkling approaches, designs, and sensing strategies are extrapolated into future applications. DA - 2022/9/1/ PY - 2022/9/1/ DO - 10.1002/smll.202203491 SP - SN - 1613-6829 KW - flexibility KW - sensors KW - stretchability KW - surface wrinkling KW - wearable devices ER - TY - JOUR TI - Visualization of Human Skeletal Muscle Mechanical Anisotropy by Using Dual-Direction Shear Wave Imaging AU - Xu, Guo-Xuan AU - Chen, Pei-Yu AU - Jiang, Xiaoning AU - Huang, Chih-Chung T2 - IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING AB - Objective: Ultrasound (US) shear wave elasticity imaging (SWEI) is a mature technique for diagnosing the elasticity of isotropic tissues. However, the elasticity of anisotropic tissues, such as muscle and tendon, cannot be diagnosed correctly using SWEI because the shear wave velocity (SWV) varies with tissue fiber orientations. Recently, SWEI has been studied for measuring the anisotropic properties of muscles by rotating the transducer; however, this is difficult for clinical practice. Methods: In this study, a novel dual-direction shear wave imaging (DDSWI) technique was proposed for visualizing the mechanical anisotropy of muscles without rotation. Longitudinal and transverse shear waves were created by a specially designed external vibrator and supersonic pushing beam, respectively; the SWVs were then tracked using ultrafast US imaging. Subsequently, the SWV maps of two directions were obtained at the same scanning cross section, and the mechanical anisotropy was represented as the ratio between them at each pixel. Results: The performance of DDSWI was verified using a standard phantom, and human experiments were performed on the gastrocnemius and biceps brachii. Experimental results of phantom revealed DDSWI exhibited a high precision of <0.81% and a low bias of <3.88% in SWV measurements. The distribution of anisotropic properties in muscle was visualized with the anisotropic ratios of 1.54 and 2.27 for the gastrocnemius and biceps brachii, respectively. Conclusion: The results highlight the potential of this novel anisotropic imaging in clinical applications because the conditions of musculoskeletal fiber orientation can be easily and accurately evaluated in real time by DDSWI. DA - 2022/9// PY - 2022/9// DO - 10.1109/TBME.2022.3152896 VL - 69 IS - 9 SP - 2745-2754 SN - 1558-2531 KW - Muscles KW - Imaging KW - Transducers KW - Elasticity KW - Biomedical measurement KW - Anisotropic magnetoresistance KW - Elastography KW - Muscle anisotropy KW - skeletal muscle KW - shear wave elasticity imaging (SWEI) KW - tissue elasticity KW - tissue isotropy ER - TY - JOUR TI - Resembled Tactile Feedback for Object Recognition Using a Prosthetic Hand AU - Vargas, Luis AU - Huang, He AU - Zhu, Yong AU - Kamper, Derek AU - Hu, Xiaogang T2 - IEEE ROBOTICS AND AUTOMATION LETTERS AB - Tactile feedback in the hand is essential for interaction with objects. Here, we evaluated how artificial tactile sensation affected the recognition of object properties using a myoelectrically controlled prosthetic hand. Electromyogram signals from the flexor and extensor finger muscles were used to continuously control either prosthetic joint velocity or position. Participants grasped objects of varying shape or size using the prosthetic hand. Tactile feedback was evoked by transcutaneous nerve stimulation along the participant's upper arm and modulated based on the prosthetic-object contact force. Multi-channel electrical stimulation targeted the median and ulnar nerve bundles to produce resembled tactile sensations at distinct hand regions. The results showed that participants could gauge the onset timing of tactile feedback to discern object shape and size. We also found that the position-controller led to a greater recognition accuracy of object size compared with velocity-control, potentially due to supplemental joint position information from muscle activation level. Our findings demonstrate that non-invasive tactile feedback can enable effective object shape and size recognition during prosthetic control. The evaluation of tactile feedback across myoelectric controllers can help understand the interplay between sensory and motor pathways involved in the control of assistive devices. DA - 2022/10// PY - 2022/10// DO - 10.1109/LRA.2022.3196958 VL - 7 IS - 4 SP - 10977-10984 SN - 2377-3766 KW - Tactile feedback KW - prosthetic control KW - object recognition KW - transcutaneous nerve stimulation ER - TY - JOUR TI - A Permanent Magnet Synchronous Spherical Motor for High-Mobility Servo-Actuation AU - Shah, Jay A. AU - Miller, Samuel R. AU - Jernigan, Shaphan R. AU - Buckner, Gregory D. T2 - MACHINES AB - The development of direct-drive spherical motors offers a potential solution to the limitations of conventional multiple degree-of-freedom (DOF) actuators, which typically utilize single-DOF joints (rotational and/or prismatic), arranged in series or parallel and powered by multiple single-DOF actuators. These configurations can be accompanied by kinematic singularities, backlash, limited power density and efficiency, and computationally expensive inverse kinematics. This paper details the design, fabrication and experimental testing of permanent magnet synchronous spherical motors (PMSSM) for multi-DOF servo-actuation. Its stator-pole arrangement is based on a Goldberg polyhedron, with each pole comprised of hexagonal or pentagonal inner and outer plates. The stator geometry and winding configurations are optimized using electromagnetic finite element analysis. A custom-made controller board includes a microcontroller, servo drivers, a wireless serial interface, and a USB PC interface. Angular orientation is sensed using an inertial measurement unit in wireless communication with the microcontroller. A PID controller is implemented and demonstrated for time-varying reference trajectories. DA - 2022/8// PY - 2022/8// DO - 10.3390/machines10080612 VL - 10 IS - 8 SP - SN - 2075-1702 KW - spherical motor KW - permanent magnet synchronous motor KW - PID control ER - TY - CONF TI - Detaching Water Droplets from a Fiber using a Magnetic Field AU - Farhan, M. AU - Tafreshi, H.V. T2 - 13th World Filtration Congress C2 - 2022/10/5/ C3 - 13th World Filtration Congress CY - San Diego, CA DA - 2022/10/5/ PY - 2022/10/5/ ER - TY - CONF TI - Adhesion Forces on A Droplet Sandwiched between Hydrophobic Fibrous Layers AU - Moghadam, A. AU - Tafreshi, H.V. T2 - 13th World Filtration Congress C2 - 2022/10/5/ C3 - 13th World Filtration Congress CY - San Diego, CA DA - 2022/10/5/ PY - 2022/10/5/ ER - TY - CONF TI - Studying Filtration through Micro- And Macro-Scale Modeling and Experiment AU - Tafreshi, H.V. T2 - 13th World Filtration Congress C2 - 2022/10/5/ C3 - 13th World Filtration Congress CY - San Diego, CA DA - 2022/10/5/ PY - 2022/10/5/ ER - TY - JOUR TI - Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders AU - Saptarshi, Sourabh AU - DeJong, Matthew AU - Rock, Christopher AU - Anderson, Iver AU - Napolitano, Ralph AU - Forrester, Jennifer AU - Lapidus, Saul AU - Kaoumi, Djamel AU - Horn, Timothy T2 - JOM AB - Abstract Laser powder bed fusion (LPBF) additive manufacturing (AM) is a promising route for the fabrication of oxide dispersion strengthened (ODS) steels. In this study, 14YWT ferritic steel powders were produced by gas atomization reaction synthesis (GARS). The rapid solidification resulted in the formation of stable, Y-containing intermetallic Y 2 Fe 17 on the interior of the powder and a stable Cr-rich oxide surface. The GARS powders were consolidated with LPBF. Process parameter maps identified a stable process window resulting in a relative density of 99.8%. Transmission electron microscopy and high-energy x-ray diffraction demonstrated that during LPBF, the stable phases in the powder dissociated in the liquid melt pool and reacted to form a high density (1.7 × 10 20 /m 3 ) of homogeneously distributed Ti 2 Y 2 O 7 pyrochlore dispersoids ranging from 17 to 57 nm. The use of GARS powder bypasses the mechanical alloying step typically required to produce ODS feedstock. Preliminary mechanical tests demonstrated an ultimate tensile and yield strength of 474 MPa and 312 MPa, respectively. DA - 2022/8/2/ PY - 2022/8/2/ DO - 10.1007/s11837-022-05418-6 VL - 8 SP - SN - 1543-1851 ER - TY - JOUR TI - New insight into the flexural rigidity of multi-filament yarn AU - Luan, Kun AU - Kirkwood, Elizabeth AU - Newman, Zoe AU - West, Andre AU - DenHartog, Emiel T2 - TEXTILE RESEARCH JOURNAL AB - Filament yarn is one of the most widely used soft strands in the textile industry; it exhibits excellent flexibility and is capable of being used in various productions, including knitting, weaving, braiding, sewing, and embroidery. The inherent complex interlacement between fibers, including twist, entanglement, and yarn geometry, often exhibits a nonlinear response to external loads. In addition, the interlacement of fibers also introduces difficulties when accurately measuring the flexural property of multi-filament yarn. In particular, the flexural rigidity of the yarn strongly influences the quality of end products when incorporated into novel textile technologies. In this paper, we developed a three-point bending instrument and a method for measuring the flexural rigidity of filament yarn. A representative point obeyed from Coplan’s construction on the bending constitutive curve was determined to obtain pure flexural rigidity. Furthermore, the bending process and deformations across cross-sections of filament yarns were discussed. The research provides new physical insights into the yarn bending property with the consideration of eliminating the sub-deformation variabilities. The work also paves the way for the accurate and quick measurement of the flexural rigidity of high length-to-width ratio soft materials by a three-point bending method. DA - 2022/8/1/ PY - 2022/8/1/ DO - 10.1177/00405175221114655 VL - 8 SP - SN - 1746-7748 KW - Three-point bending KW - pretension KW - spun yarn KW - conductive yarn KW - flexural rigidity KW - knittability ER - TY - JOUR TI - Experimental Investigation of Boundary Condition Effects in Bipennate Fluidic Artificial Muscle Bundles AU - Hart, Rebecca AU - Duan, Emily AU - Bryant, Matthew T2 - BIOINSPIRATION, BIOMIMETICS, AND BIOREPLICATION XII AB - In this study, the implementation and performance of bipennate topology fluidic artificial muscle (FAM) bundles operating under varying boundary conditions is investigated and quantified experimentally. Soft actuators are of great interest to design engineers due to their inherent flexibility and potential to improve safety in human robot interactions. McKibben fluidic artificial muscles are soft actuators which exhibit high force to weight ratios and dynamically replicate natural muscle movement. These features, in addition to their low fabrication cost, set McKibben FAMs apart as attractive components for an actuation system. Previous studies have shown that there are significant advantages in force and contraction outputs when using bipennate topology FAM bundles as compared to the conventional parallel topology1 . In this study, we will experimentally explore the effects of two possible boundary conditions imposed on FAMs within a bipennate topology. One boundary condition is to pin the muscle fiber ends with fixed pin spacings while the other is biologically inspired and constrains the muscle fibers to remain in contact. This paper will outline design considerations for building a test platform for bipennate fluidic artificial muscle bundles with varying boundary conditions and present experimental results quantifying muscle displacement and force output. These metrics are used to analyze the tradespace between the two boundary conditions and the effect of varying pennation angles. DA - 2022/// PY - 2022/// DO - 10.1117/12.2615896 VL - 12041 SP - SN - 1996-756X KW - pennate topology KW - soft actuators KW - fluidic artificial muscles KW - muscle topology KW - bioinspired ER - TY - JOUR TI - Control of a dynamic load emulator for hardware-in-the-loop testing of fluidic artificial muscle bundles AU - Mazzoleni, Nicholas AU - Kim, Jeong Yong AU - Bryant, Matthew T2 - BIOINSPIRATION, BIOMIMETICS, AND BIOREPLICATION XII AB - Fluidic artificial muscles (FAMs) have emerged as a viable and popular robotic actuation technique due to their low cost, compliant nature, and high force-to-weight-ratio. In recent years, the concept of variable recruitment has emerged as a way to improve the efficiency of conventional hydraulic robotic systems. In variable recruitment, groups of FAMs are bundled together and divided into individual motor units. Each motor unit can be activated independently, which is similar to the sequential activation pattern observed in mammalian muscle. Previous researchers have performed quasistatic characterizations of variable recruitment bundles and some simple dynamic analyses and experiments with a simple 1- DOF robot arm. We have developed a linear hydraulic characterization testing platform that will allow for the testing of different types of variable recruitment bundle configurations under different loading conditions. The platform consists of a hydraulic drive cylinder that acts as a cyber-physical hardware-in-the-loop dynamic loading emulator and interfaces with the variable recruitment bundle. The desired inertial, damping and stiffness properties of the emulator can be prescribed and achieved through an admittance controller. In this paper, we test the ability of this admittance controller to emulate different inertial, stiffness, and damping properties in simulation and demonstrate that it can be used in hardware through a proof-of-concept experiment. The primary goal of this work is to develop a unique testing setup that will allow for the testing of different FAM configurations, controllers, or subsystems and their responses to different dynamic loads before they are implemented on more complex robotic systems. DA - 2022/// PY - 2022/// DO - 10.1117/12.2612920 VL - 12041 SP - SN - 1996-756X KW - Fluidic artificial muscles KW - hardware-in-the-loop KW - load emulator KW - cyber-physical system KW - bioinspired robotics ER - TY - JOUR TI - Soft wearable sensors for monitoring symptoms of COVID-19 and other respiratory diseases: a review AU - Liu, Yuxuan AU - Shukla, Darpan AU - Newman, Holly AU - Zhu, Yong T2 - PROGRESS IN BIOMEDICAL ENGINEERING AB - The COVID-19 pandemic has put extraordinary stress on medical systems and global society more broadly. The condition of infected patients may deteriorate rapidly due to overburdened hospital systems. This raises an urgent need for real-time and remote monitoring of physiological parameters to address the challenges associated with the COVID-19 pandemic. This review will present recent progress on soft wearable sensors that can potentially be used for monitoring respiratory diseases such as COVID-19. First, emerging monitoring devices and systems that can monitor key physiological parameters as suggested by the Centers for Disease Control and Prevention (e.g. body temperature, respiration rate, heart rate, oxygen saturation and body movement) are reviewed. Then, multimodal sensor systems consisting of two or more correlative sensors are presented. This review will conclude with challenges and future directions for wearable sensors for the diagnosis and therapy of respiratory diseases. While this review focuses on COVID-19, the sensing technologies reviewed can be applicable to other respiratory diseases such as H1N1 influenza. DA - 2022/1// PY - 2022/1// DO - 10.1088/2516-1091/ac2eae VL - 4 IS - 1 SP - SN - 2516-1091 KW - respiratory diseases KW - wearable sensors KW - soft sensors KW - COVID-19 KW - health monitoring ER - TY - JOUR TI - Enhanced piezoelectric and dielectric properties of AC poled sliver-mode Pb(In1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3-PbTiO3 single crystals for ultrasonic abdomen probes AU - Sun, Yiqin AU - Ota, Yuhei AU - Kim, Hwang-Pill AU - Fujii, Tadashi AU - Yamashita, Yohachi AU - Karaki, Tomoaki AU - Jiang, Xiaoning AU - Wang, Zhuangkai T2 - JAPANESE JOURNAL OF APPLIED PHYSICS AB - Abstract The effect of AC poling (ACP) on the piezoelectric and dielectric properties of diced sliver-mode vibrators (L13 × W0.15–0.30 × T0.51 mm 3 ) was investigated for a convex abdomen ultrasound (US) probe that is made of a large Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 −0.3PbTiO 3 (PIN-PMN-PT) single crystal (SC) plate (L13 × W60 × T0.51 mm 3 ). The SC was manufactured by the continuous feeding Bridgman (CF-BM) method. The ε 33 T / ε 0 aging rate (AR) of both DCP and ACP large plate SCs were found to be within 1%/decade suggesting no obvious property degradation. After array dicing, a considerable decrease in electromechanical and dielectric properties was observed. After a post-dicing DCP, the diced DCP-DCP 0.15 mm wide SC slivers showed ε 33 T / ε 0 and electromechanical coupling factor ( k ′ 33 ) of 4300 and 89.1%, respectively. The diced ACP-DCP 0.15 mm wide SC slivers showed improved ε 33 T / ε 0 and k ′ 33 of 5980 and 92.2%, respectively, which are considered useful in practical medical array transducer applications. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.35848/1347-4065/ac8142 VL - 61 IS - SN SP - SN - 1347-4065 ER - TY - JOUR TI - New International Guidelines and Consensus on the Use of Lung Ultrasound AU - Demi, Libertario AU - Wolfram, Frank AU - Klersy, Catherine AU - De Silvestri, Annalisa AU - Ferretti, Virginia Valeria AU - Muller, Marie AU - Miller, Douglas AU - Feletti, Francesco AU - Welnicki, Marcin AU - Buda, Natalia AU - Skoczylas, Agnieszka AU - Pomiecko, Andrzej AU - Damjanovic, Domagoj AU - Olszewski, Robert AU - Kirkpatrick, Andrew W. AU - Breitkreutz, Raoul AU - Mathis, Gebhart AU - Soldati, Gino AU - Smargiassi, Andrea AU - Inchingolo, Riccardo AU - Perrone, Tiziano T2 - JOURNAL OF ULTRASOUND IN MEDICINE AB - Following the innovations and new discoveries of the last 10 years in the field of lung ultrasound (LUS), a multidisciplinary panel of international LUS experts from six countries and from different fields (clinical and technical) reviewed and updated the original international consensus for point-of-care LUS, dated 2012. As a result, a total of 20 statements have been produced. Each statement is complemented by guidelines and future developments proposals. The statements are furthermore classified based on their nature as technical (5), clinical (11), educational (3), and safety (1) statements. DA - 2022/8/22/ PY - 2022/8/22/ DO - 10.1002/jum.16088 SP - SN - 1550-9613 KW - A-lines KW - artificial intelligence KW - B-lines KW - COVID-19 KW - lung ultrasound KW - lung ultrasound protocols KW - lung ultrasound standardization KW - LUS safety assurance KW - point of care ultrasound KW - post-COVID-19 KW - quantitative ultrasound KW - SARS-CoV-2 KW - sonographic interstitial syndrome KW - vertical artifacts ER - TY - JOUR TI - Response of a plate with piezoelectric elements to turbulent pressure fluctuation in supersonic flow AU - Freydin, Maxim AU - Dowell, Earl H. AU - Varigonda, Santosh Vaibhav AU - Narayanaswamy, Venkateswaran T2 - JOURNAL OF FLUIDS AND STRUCTURES AB - The aeroelastic response of a plate with supersonic freestream flow on one side and a shallow cavity on the other to turbulent pressure fluctuations is investigated computationally and experimentally. An empirical model is developed for the pressure fluctuations in a turbulent boundary layer that accounts for spatial and spectral variations in the pressure field. Supersonic wind tunnel tests were conducted in a Mach 2.5 flow with and without an impinging shock at the plate surface. In both cases the boundary layer was turbulent. The impinging shock creates shock-wave boundary-layer interaction, which alters the characteristics of the pressure fluctuations. Pressure-sensitive paint was used to measure the unsteady pressure on the surface of a rigid plate and characterize the pressure field (local mean, rms, and the spatial coherence length) and piezoelectric patches were used as sensors to measure the response of an elastic plate. The extracted pressure parameters were used to simulate the fluid–structure response and correlate with experiments. The computed pressure perturbation due to plate motion is found to be small relative to the natural pressure fluctuation for the fluid/structural configuration studied. Computed and measured power spectra of the piezoelectric element voltage show good agreement over a wide range of structural natural frequencies. Aeroelastic response sensitivity to pressure fluctuation coherence length was also investigated computationally. It is found that with small fluid elements, which represent small-scale uncorrelated noise, the structural response is relatively small because the excitation is filtered by the plate dynamics. Experimental results suggest that the effective excitation spatial scale is on the order of the boundary layer thickness. DA - 2022/10// PY - 2022/10// DO - 10.1016/j.jfluidstructs.2022.103696 VL - 114 SP - SN - 1095-8622 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85135818767&partnerID=MN8TOARS KW - Supersonic KW - Fluctuating pressure KW - Pressure sensitive paint KW - Plate KW - Piezoelectric materials ER - TY - JOUR TI - Template‐Free Scalable Fabrication of Linearly Periodic Microstructures by Controlling Ribbing Defects Phenomenon in Forward Roll Coating for Multifunctional Applications AU - Islam, Md Didarul AU - Perera, Himendra AU - Black, Benjamin AU - Phillips, Matthew AU - Chen, Muh‐Jang AU - Hodges, Greyson AU - Jackman, Allyce AU - Liu, Yuxuan AU - Kim, Chang‐Jin AU - Zikry, Mohammed AU - Khan, Saad AU - Zhu, Yong AU - Pankow, Mark AU - Ryu, Jong Eun T2 - Advanced Materials Interfaces AB - Abstract Periodic micro/nanoscale structures from nature have inspired the scientific community to adopt surface design for various applications, including superhydrophobic drag reduction. One primary concern of practical applications of such periodic microstructures remains the scalability of conventional microfabrication technologies. This study demonstrates a simple template‐free scalable manufacturing technique to fabricate periodic microstructures by controlling the ribbing defects in the forward roll coating. Viscoelastic composite coating materials are designed for roll‐coating using carbon nanotubes (CNT) and polydimethylsiloxane (PDMS), which helps achieve a controllable ribbing with a periodicity of 114–700 µm. Depending on the process parameters, the patterned microstructures transition from the linear alignment to a random structure. The periodic microstructure enables hydrophobicity as the water contact angles of the samples ranged from 128° to 158°. When towed in a static water pool, a model boat coated with the microstructure film shows 7%–8% faster speed than the boat with a flat PDMS film. The CNT addition shows both mechanical and electrical properties improvement. In a mechanical scratch test, the cohesive failure of the CNT‐PDMS film occurs in ≈90% higher force than bare PDMS. Moreover, the nonconductive bare PDMS shows sheet resistance of 747.84–22.66 Ω □ −1 with 0.5 to 2.5 wt% CNT inclusion. DA - 2022/8/26/ PY - 2022/8/26/ DO - 10.1002/admi.202201237 VL - 9 IS - 27 SP - 2201237 J2 - Adv Materials Inter LA - en OP - SN - 2196-7350 2196-7350 UR - http://dx.doi.org/10.1002/admi.202201237 DB - Crossref KW - multifunctional surfaces KW - periodic microtrenches KW - ribbing instabilities KW - roll coating KW - scalable manufacturing ER - TY - JOUR TI - Temperature reconstruction of an axisymmetric enclosed reactive flow using simultaneous background oriented schlieren and infrared thermography AU - Wahls, Benjamin H. AU - Ekkad, Srinath V T2 - MEASUREMENT SCIENCE AND TECHNOLOGY AB - Abstract The temperature distribution of a premixed methane air flame running at a Reynolds number of 1300 on a circular burner, 12.7 mm diameter, enclosed in a fused silica cylindrical liner has been experimentally reconstructed using a non-invasive approach combining background oriented schlieren (BOS) and infrared (IR) thermography. BOS is used to characterize both the air ambient to the system, using an existing technique called 3D ray tracing, and the reactive flow inside the enclosure, with a novel modified version of 3D ray tracing. IR thermography is used to characterize the thermal/optical characteristics of the quartz glass enclosure itself, since the information is required as BOS is a line of sight imaging technique. Out of necessity, an approximated species independent relationship is used to calculate flow temperature from refractive index. A simulation is used to show this error is in the range of 5.8%–7%. Additionally, it is found that drastically simplifying the approach by removing the IR thermography system entirely and using the near outer wall air temperature from BOS/3D ray tracing to characterize the internal temperature of the quartz liner itself only causes a 1.5%–3.8% degradation in the accuracy of the reconstructed temperature field. The technique as presented is a relatively inexpensive, experimentally simple approach capable of determining the steady state temperature characteristics of optically accessible axisymmetric reactive flows. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.1088/1361-6501/ac83e2 VL - 33 IS - 11 SP - SN - 1361-6501 KW - background oriented schlieren KW - infrared thermography KW - noninvasive KW - temperature KW - measurement KW - enclosed KW - reactive flow ER - TY - JOUR TI - Coupled electromagnetic and mechanical modeling and detection of buried objects AU - Elbadry, Mohamed AU - Wetherington, J. AU - Zikry, M.A. T2 - Applications in Engineering Science AB - A time domain finite element (FE) framework was used to investigate the coupled electromagnetic (EM) and mechanical behavior of buried target systems. The coupling of the EM and mechanical fields is through using the Lorentz Force as the body force in the mechanical Cauchy equation of motion. The coupling is sequential where the EM fields and Lorentz force are first solved for, then they are used as inputs for the Cauchy equations of motion. Predictions were obtained for different loading conditions and the Method of Morris sensitivity analysis was used to understand how different mechanical and EM variables affect the buried target system. These predictions indicate that target permeability and depth had the most significant and dominant effects on the behavior of the buried target system. DA - 2022/6// PY - 2022/6// DO - 10.1016/j.apples.2022.100106 VL - 10 UR - https://doi.org/10.1016/j.apples.2022.100106 ER - TY - CONF TI - Pressure and Strain Measurement on a 10° Control Surface of a Slender Cone in Hypersonic Flow AU - Hedge, A. AU - MacIntyre, Z. AU - Hubner, J.P. AU - Chen, M. AU - Pandey, A. AU - Flood, J.T. AU - Casper, K.M. T2 - AIAA AVIATION 2022 Forum AB - This paper presents the results of an experimental technique to acquire full-field pressure and strain fields on the windward side of a 10° flap attached to a slender cone-slice model. Tests were conducted in the Hypersonic Wind Tunnel (M = 5, Re= 9 – 14×〖10〗^6/m, air) at Sandia National Laboratories. The flap was coated with a fast-response, pressure-sensitive paint sprayed over a photoelastic coating and located near the trailing-edge of an axial slice along the 7° slender cone. This experiment was part of a sponsored project to develop the two-coating luminescent measurement technique and apply to high-speed, fluid-structure interaction environments. Results using a low-speed micropolarizer camera with four polarization orientations show that the technique is sensitive to pressure and strain, measuring an increasing pressure and decreasing strain from leading- to trailing-edge over the surface of the flap. At the low Re condition, the pressure signal captures the separated region near the flap leading edge and compares well with schlieren and oil-film measurements, the latter on a 10° wedge. Aerodynamic heating during the run does affect the pressure signal, likely resulting in an overestimation of pressure. Results using a conventional high-speed camera with a single linear polarizer captures the first bending and torsional modes of vibration when the flap is excited by transient shutdown conditions; however, coupling is difficult to detect in the pressure response due to baseline noise and the slower temporal response of the pressure coating. C2 - 2022/6// C3 - AIAA AVIATION 2022 Forum CY - Chicago, IL DA - 2022/6// PY - 2022/6/27/ DO - 10.2514/6.2022-4043 ER - TY - CONF TI - Investigation of Fountain Effect in Dual-Rotor/Wing Interaction at Low Reynolds Number AU - Chen, M. AU - Shen, J. AU - Hubner, J.P. T2 - AIAA AVIATION 2022 Forum AB - This paper conducts a parametric investigation on whether the fountain effect in dual rotor/wing interaction exists at low disk loading and Reynolds number (disk loading < 100 N/m^2 and Reynolds number < 100,000). A commercial computational fluid dynamics package specifically developed for rotorcraft studies, RotCFD, in which the rotor is modeled as a distribution of momentum sources, was used. Numerical results are compared to an experimental study including force measurements and surface pressure measurements. The comparisons are employed to assess the accuracy of RotCFD results and help evaluate the formation of the fountain effect and its effect on rotor thrust and download force on the wing. C2 - 2022/6// C3 - AIAA AVIATION 2022 Forum CY - Chicago, IL DA - 2022/6// PY - 2022/6/27/ DO - 10.2514/6.2022-3816 ER - TY - JOUR TI - Variable-Gain Sliding Mode Control for Quadrotor Vehicles: Lyapunov-based Analysis and Finite-Time Stability AU - Miranda-Colorado, R. AU - Dominguez-Silva, I. AU - Aguilar, L.T. T2 - IEEE Transactions on Control Systems Technology DA - 2022/// PY - 2022/// ER - TY - CONF TI - Design and Experimental Validation of a High Power Actuator for Knee Prosthesis with Low Gear Ratio Transmission AU - Dominguez-Silva, I. C2 - 2022/// C3 - IEEE/ASME Transactions on Mechatronics with The 2022 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM 2022 DA - 2022/// ER - TY - RPRT TI - Non-Nuclear Exploration of the Solar System Study AU - Brophy, John AU - Pellegrino, Sergio AU - Lubin, Philip AU - Alkalai, Leon AU - Atwater, Harry AU - Biswas, Abi AU - Boca, Andreea AU - Carr, Greg AU - Davoyan, Artur AU - Frazier, William AU - Gdoutos, Terry AU - Grandidier, Jonathan AU - Hogstrom, Kristina AU - Hughes, Mike AU - Johnson, Les AU - Kelzenberg, Michael AU - Lee, Andrew AU - Luther, Joseph AU - Marshall, Michael AU - Marrese-Reading, Colleen AU - McCarty, Steve AU - McNutt, Ralph AU - Petro, Elaine AU - Polk, James AU - Scully, Jennifer AU - Sekerak, Michael AU - Sellers, Ian A3 - California Institute of Technology DA - 2022/// PY - 2022/// DO - 10.7907/H62P-6328 PB - California Institute of Technology UR - https://resolver.caltech.edu/CaltechAUTHORS:20220503-222804071 ER - TY - CONF TI - Bistable Deployable Composite Booms With Parabolic Cross-Sections AU - Lee, Andrew J. AU - Fernandez, Juan M. AU - Daye, Jacob G. AB - This paper investigates how stable equilibrium states in the extended and coiled configurations can be predicted in thin-shelled composite booms with parabolic cross-sections. These conic shapes potentially offer greater stiffness properties when compared to circular cross-sections, which is critical for improving the load bearing performance of deployed booms. Inducing bistability through the choice of composite shell layups in parabolic booms would allow for controllable self-deployment due to a less energetic coiled state when compared to monostable booms. An inextensional analytical model is used to predict the stable coiled diameters of tape spring and Collapsible Tubular Mast (CTM) booms with parabolic cross-sections. The parabolic section is discretized into circular segments using biarc spline interpolation, which allows them to be integrated into the strain energy minimization procedure used to obtain the equilibrium states. When the parabolic booms are parametrically compared against circular booms with identical layups, flattened height, and mass, the former are found to generally have better stiffness performance while being less efficient in stowed volume as evidenced by larger coiled diameters. Analytical coiled diameters and their strain energy are verified with finite element simulations for optimal parabolic tape spring and CTM booms. C2 - 2022/1/3/ C3 - AIAA Scitech 2022 Forum DA - 2022/1/3/ DO - 10.2514/6.2022-2264 PB - American Institute of Aeronautics and Astronautics UR - http://dx.doi.org/10.2514/6.2022-2264 ER - TY - JOUR TI - Mass efficiency of strip-based coilable space structures AU - Lee, Andrew J. AU - Pellegrino, Sergio T2 - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES AB - This paper presents a general semi-analytical study of the mass efficiency of coilable plate-like space structures. A bending architecture based on four diagonal booms that support parallel strips is compared to a cable-stayed architecture in which vertical booms and cable stays support the diagonal booms at the tip. Limiting conditions of global buckling, local buckling, material failure, and excessive deflection define the design space for each architecture. Considering pressure loads spanning several orders of magnitude, the optimal areal density of structures of size varying from a few meters to hundreds of meters is determined for both architectures. Design charts for optimal designs are provided for a range of sizes, loads, and deflection limits. It is shown that the cable-stayed architecture is always lighter than the bending architecture, from a few percent to over 30%. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.1016/j.ijsolstr.2022.111867 VL - 254 SP - SN - 1879-2146 UR - http://dx.doi.org/10.1016/j.ijsolstr.2022.111867 KW - Space structures KW - Structural design KW - Mass efficiency KW - Areal density KW - Deployable KW - Cable-stayed ER - TY - JOUR TI - Particle Swarm Optimization Algorithm for Guided Waves Based Damage Localization Using Fiber Bragg Grating Sensors in Remote Configuration AU - Soman, Rohan AU - Boyer, Alex AU - Kim, Jee Myung AU - Peters, Kara T2 - SENSORS AB - Structural health monitoring (SHM) systems may allow a reduction in maintenance costs and extend the lifetime of the structure. As a result, they are of interest to the research community. Ideally, the SHM methods should be low cost, while being able to detect and localize small levels of damage reliably and accurately. The fiber Bragg grating (FBG) sensors are light in weight, insensitive to electric and magnetic fields, and can be embedded. The edge filtering configuration for transduction allows the use of FBG for guided wave (GW) sensing. This sensitivity may be further enhanced through their application in the remote bonded configuration. This paper provides a proof-of-concept for the use of remotely bonded FBG for damage localization. In order to improve the computational efficiency, a particle swarm optimization (PSO) based algorithm is developed. The PSO allows a significant improvement in the computation time which makes it better suited for real-time damage localization. The proposed objective function is based on the exponential elliptical approach. First, the suitability of the PSO for damage localization is shown. Then the performance of the chosen objective function is compared with the brute-force algorithm as well as other objective functions found in the literature. The methodology is employed on a simple aluminum plate. The results indicate that indeed the objective function along with the PSO is suitable for damage localization. Also as the objective function is developed taking into consideration the specific challenges with the use of FBG sensors, performs better than the other objective functions as well as the brute force algorithm. DA - 2022/8// PY - 2022/8// DO - 10.3390/s22166000 VL - 22 IS - 16 SP - SN - 1424-8220 UR - https://www.mdpi.com/1424-8220/22/16/6000 KW - guided waves KW - fiber Bragg grating (FBG) sensors KW - remote bonding KW - damage localization KW - particle swarm optimization ER - TY - JOUR TI - Cephalopod-inspired snapshot multispectral sensor based on geometric phase lens and stacked organic photodetectors AU - Altaqui, Ali AU - Schrickx, Harry AU - Gyurek, Sydney AU - Sen, Pratik AU - Escuti, Michael AU - Brendan T. O'Connor, AU - Kudenov, Michael T2 - OPTICAL ENGINEERING AB - Multispectral imaging (MSI) is a valuable sensing modality for applications that require detecting a scene’s chemical characteristics. Existing MSI techniques utilize a filter wheel or color filter arrays, which are subject to reduced temporal or spatial resolution. In this work, we present a cephalopod-inspired multispectral organic sensor (CiMOS) based on geometric phase lenses (GPLs) and organic photovoltaics (OPVs) to enable aberration-based color sensing. We mimic the approach by which animals with single-type photoreceptors perceive colors via chromatic aberration. The intrinsic chromatic aberration of GPLs allows for multispectral sensing by stacking precisely patterned OPVs within specific spectrally dependent focal lengths. We provide simulations and a proof of concept of the CiMOS and highlight its advantages, including its simple design and snapshot multi-color detection using only a single axial position. Experimental results demonstrate the sensor’s ability to detect four colors with full width at half maximum spectral resolution as low as 35 nm. DA - 2022/7/1/ PY - 2022/7/1/ DO - 10.1117/1.OE.61.7.077104 VL - 61 IS - 7 SP - SN - 1560-2303 KW - multispectral sensing KW - pancharatnam-berry phase KW - organic photovoltaics KW - geometric phase lens KW - imaging KW - sensors KW - spectroscopy ER - TY - JOUR TI - Exploration of the dislocation-electrochemistry relation in LiFePO4 cathode materials AU - Chen, Hongjiang AU - Kim, Sangwook AU - Huang, Hsiao-Ying Shadow T2 - ACTA MATERIALIA AB - Defects, such as dislocations, in electrode materials play a significant role in the performance of lithium-ion batteries. The dislocation-electrochemistry relation has only been observed experimentally and not been fully clarified. Computational studies on this mechanism were also very limited, especially the altered cyclic voltammetry behaviors and associated effective diffusivity. This work focuses on the influences of few characteristics of dislocations on the electrochemical performance of an anisotropic cathode material, lithium iron phosphate (LiFePO 4 ). Utilizing linear elastic mechanics and the superposition principle, we study stress and displacement fields of a LiFePO 4 particle containing different densities and orientations of dislocations. With the mechanical-electrochemical coupling effects expressed by the modified Butler-Volmer equation and using the finite different method, the cyclic voltammetry curves for different dislocation configurations in the particle are investigated. Our results show that introducing dislocations can shift and distort the cyclic voltammetry curves, especially at one specific dislocation orientation. It is also found that the Li-ion molar fraction-dependent partial molar volume is an important prerequisite of the distortion in cyclic voltammetry curves. Moreover, the altered cyclic voltammetry curves at different scanning rates indicate the improvements of electrical power, stored electrical energy, and the effective diffusivity of lithium. Our discrete dislocation model indicates that the capacity loss of LiFePO 4 nanoparticles can be alleviated by introducing tailored dislocations. This study assists the understanding of electrode materials with pre-existing dislocations and provides strategies of using defect engineering to improve the kinetic performance in lithium-ion batteries. DA - 2022/9/15/ PY - 2022/9/15/ DO - 10.1016/j.actamat.2022.118158 VL - 237 SP - SN - 1873-2453 KW - Dislocations KW - Cyclic voltammetry KW - Electrochemistry KW - Stress KW - Displacement KW - Lithium -ion battery ER - TY - JOUR TI - Bidirectional, unlike unidirectional transport, allows transporting axonal cargos against their concentration gradient AU - Kuznetsov, Ivan A. AU - Kuznetsov, Andrey V T2 - JOURNAL OF THEORETICAL BIOLOGY AB - Even though most axonal cargos are synthesized in the soma, the concentration of many of these cargos is larger at the presynaptic terminal than in the soma. This requires transport of these cargos from the soma to the presynaptic terminal or other active sites in the axon. Axons utilize both bidirectional (for example, slow axonal transport) and unidirectional (for example, fast anterograde axonal transport) modes of cargo transport. Bidirectional transport seems to be less efficient because it requires more time and takes more energy to deliver cargos. In this paper, we studied a family of models which differ by the modes of axonal cargo transport (such as anterograde and retrograde motor-driven transport and passive diffusion) as well as by the presence or absence of pausing states. The models are studied to investigate their ability to describe axonal transport against the cargo concentration gradient. We argue that bidirectional axonal transport is described by a higher-order mathematical model, which allows imposing cargo concentration not only at the axon hillock but also at the axon terminal. The unidirectional transport model allows only for the imposition of cargo concentration at the axon hillock. Due to the great lengths of the axons, anterograde transport mostly relies on molecular motors, such as kinesins, to deliver cargos synthesized in the soma to the terminal and other active sites in the axon. Retrograde transport can be also motor-driven, in which case cargos are transported by dynein motors. If cargo concentration at the axon tip is higher than at the axon hillock, retrograde transport can also occur by cargo diffusion. However, because many axonal cargos are large or they assemble in multiprotein complexes for axonal transport, the diffusivity of such cargos is very small. We investigated the case of a small cargo diffusivity using a perturbation technique and found that for this case the effect of diffusion is limited to a very thin diffusion boundary layer near the axon tip. If cargo diffusivity is decreased in the model, we show that without motor-driven retrograde transport the model is unable to describe a high cargo concentration at the axon tip. To the best of our knowledge, our paper presents the first explanation for the utilization of seemingly inefficient bidirectional transport in neurons. DA - 2022/8/7/ PY - 2022/8/7/ DO - 10.1016/j.jtbi.2022.111161 VL - 546 SP - SN - 1095-8541 KW - Neuron KW - Axon KW - Mathematical modeling KW - Slow and fast axonal transport KW - Alpha-synuclein ER - TY - JOUR TI - Cosserat modeling for deformation configuration of shape memory alloy unimorph actuators AU - Kennedy, Scott AU - Vlajic, Nicholas AU - Perkins, Edmon T2 - JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES AB - Shape memory alloys (SMAs) can contract their length via a crystalline phase transition that is dependent upon their temperature and stress state. SMAs have been used as linear micro-actuators due to their high strength to weight ratio and compact structure. However, the relatively low linear contraction ([Formula: see text]4%–5% in length) limits their use. To remedy this, the SMA can be offset from a passive structure, which acts to magnify the deformation. The resulting amount of deformation depends upon the material properties and geometry of both the SMA and the passive structure. In this work, geometrically exact beam theory (also known as Cosserat theory) is coupled with SMA constitutive relations to model the maximum deformation configuration of these actuators. Four of these actuators of various lengths were fabricated and tested to verify the model. For the four actuators tested, the mean squared error between the experimental results and the Cosserat model were between 0.0702 mm (0.1% error) for the shortest actuator (66 mm in length) and 3.59 mm (2.7% error) for the longest actuator (135 mm in length). These results show that the closed form solution derived for this Cosserat beam model can accurately model the deformation of these active structures. DA - 2022/8/2/ PY - 2022/8/2/ DO - 10.1177/1045389X221109256 VL - 8 SP - SN - 1530-8138 KW - Cosserat model KW - geometrically exact beam theory KW - shape memory alloy KW - actuators ER - TY - JOUR TI - Triptorelin-functionalized PEG-coated biosynthesized gold nanoparticles: Effects of receptor-ligand interactions on adhesion to triple negative breast cancer cells AU - Uzonwanne, Vanessa O. AU - Navabi, Arvand AU - Obayemi, John D. AU - Hu, Jingjie AU - Salifu, Ali A. AU - Ghahremani, Shahnaz AU - Ndahiro, Nelson AU - Rahbar, Nima AU - Soboyejo, Winston T2 - Biomaterials Advances AB - This paper presents the results of an experimental and computational study of the adhesion of triptorelin-conjugated PEG-coated biosynthesized gold nanoparticles (GNP-PEG-TRP) to triple-negative breast cancer (TNBC) cells. The adhesion is studied at the nanoscale using a combination of atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulations. The AFM measurements showed that the triptorelin-functionalized gold nanoparticles (GNP-TRP and GNP-PEG-TRP) have higher adhesion to triple-negative breast cancer cells (TNBC) than non-tumorigenic breast cells. The increased adhesion of GNP-TRP and GNP-PEG-TRP to TNBC is also attributed to the overexpression of LHRH receptors on the surfaces of both TNBC. Finally, the molecular dynamics model reveals insights into the effects of receptor density, molecular configuration, and receptor-ligand docking characteristics on the interactions of triptorelin-functionalized PEG-coated gold nanoparticles with TNBC. A three to nine-fold increase in the adhesion is predicted between triptorelin-functionalized PEG-coated gold nanoparticles and TNBC cells. The implications of the results are then discussed for the specific targeting of TNBC. DA - 2022/4// PY - 2022/4// DO - 10.1016/j.bioadv.2022.212801 VL - 4 SP - 212801 UR - http://dx.doi.org/10.1016/j.bioadv.2022.212801 KW - Adhesion KW - PEG-coated gold nanoparticles KW - Molecular dynamic simulation KW - Triptorelin KW - AFM KW - Triple negative breast cancer ER - TY - JOUR TI - Investigation of creep properties and the cytoskeletal structures of non-tumorigenic breast cells and triple-negative breast cancer cells AU - Onwudiwe, Killian AU - Obayemi, John AU - Hu, Jingjie AU - Oparah, Josephine AU - Onyekanne, Chinyerem AU - Nwazojie, Chukwudalu AU - Aina, Toyin AU - Uzonwanne, Vanessa AU - Salifu, Ali AU - Soboyejo, Winston T2 - Journal of Biomedical Materials Research Part A AB - This article presents the correlation of creep and viscoelastic properties to the cytoskeletal structure of both tumorigenic and non-tumorigenic cells. Unique shear assay and strain mapping techniques were used to study the creep and viscoelastic properties of single non-tumorigenic and tumorigenic cells. At least 20 individual cells, three locations per cell, were studied. From the results, lower densities in the volume of actin, and keratin 18 structures were observed with the progression of cancer and were correlated to the increased creep rates and reduced mechanical properties (Young's moduli and viscosities) of tumorigenic (MDA-MB-231) cells. The study reveals significant differences between the creep and viscoelastic properties of non-tumorigenic breast cells versus tumorigenic cells. The variations in the creep strain rates are shown to be well characterized by lognormal distributions, while the statistical variations in the viscoelastic properties are well-described by normal distributions. The implications of the results are discussed for the study of discrete cell behaviors, strain and viscoelastic responses of the cell, and the role of cell cytoskeleton in the onset and progression of cancers. DA - 2022/5// PY - 2022/5// DO - 10.1002/jbm.a.37348 VL - 110 IS - 5 SP - 1004-1020 UR - http://dx.doi.org/10.1002/jbm.a.37348 KW - cancer detection KW - cell viscoelastic KW - creep properties KW - confocal microscopy KW - cytoskeletal proteins KW - immunofluorescence staining KW - relative volume density KW - shear assay ER - TY - JOUR TI - High streamwise airfoil oscillations at constant low and high incidence angles AU - Elfering, Kelsey AU - Narsipur, Shreyas AU - Granlund, Kenneth T2 - PHYSICS OF FLUIDS AB - Ratios of streamwise airfoil oscillations to the freestream velocity above 30% have not been well investigated in the literature for a reduced frequency range relevant to unsteady applications. A known departure from the experimental correlation to analytical theory for lower magnitudes of this ratio, known as surge amplitude, motivates a parameter study for constant freestream, at constant low- and high-incidence angles, to understand the circulatory lift dependence on angle of attack, Reynolds number, surge amplitude, and reduced frequency in comparison with theory and higher-order computations. To better understand the increased deviation between theory and experiment with increasing velocity fluctuation, a detailed study of surge amplitude of 0.5 is investigated. The experiment for comparison was a free-surface water tunnel with a NACA (National Advisory Committee for Aeronautics) 0018 airfoil oscillated in the streamwise direction. Force measurements, normalized by instantaneous dynamic pressure, reveal that unsteady lift is dependent on Reynolds number and reduced frequency in both attached and fully separated conditions. In separated conditions, mean and fluctuating lift show a dependency on reduced frequency for larger velocity fluctuations than a relative surge amplitude of 10%. Two-dimensional computations were found to agree well with experimental data for Reynolds number 75 k, low incidence cases, and for high incidence with reduced frequencies less than 0.15, where a fully separated upper surface boundary layer condition occurred. Agreement between computations and experiments was not favorable for reduced frequencies above 0.15 for high incidence cases, where partial upper surface boundary layer reattachment is predicted. DA - 2022/8// PY - 2022/8// DO - 10.1063/5.0097570 VL - 34 IS - 8 SP - SN - 1089-7666 UR - https://doi.org/10.1063/5.0097570 ER - TY - JOUR TI - A reconstructed discontinuous Galerkin method based on variational formulation for compressible flows AU - Li, Lingquan AU - Liu, Xiaodong AU - Luo, Hong T2 - JOURNAL OF COMPUTATIONAL PHYSICS AB - A new reconstructed discontinuous Galerkin (rDG) method based on variational formulation is developed for compressible flows. In the presented method, a higher-order piece-wise polynomial is reconstructed based on the underlying discontinuous Galerkin (DG) solution. This reconstruction is done by using a newly developed variational formulation. The variational reconstruction (VR) can be seen as an extension of the compact finite difference (FD) schemes to unstructured grids. The reconstructed variables are obtained by solving an extreme-value problem, which minimizes the jumps of the reconstructed piece-wise polynomials across the cell interfaces, and therefore maximizes the smoothness of the reconstructed solution. Intrinsically, the stencils of the presented reconstruction are the entire mesh, so this method is robust even on tetrahedral grids. A variety of benchmark test cases are presented to assess the accuracy, efficiency and robustness of this rDG method. The numerical experiments demonstrate that the developed rDG method based on variational formulation can maintain the linear stability, obtain the designed high-order accuracy, and outperform the rDG counterpart based on the least-squares reconstruction for both inviscid and viscous compressible flows. DA - 2022/10/1/ PY - 2022/10/1/ DO - 10.1016/j.jcp.2022.111406 VL - 466 SP - SN - 1090-2716 KW - ReconstructeddiscontinuousGalerkin KW - Variationalreconstruction KW - High-order KW - Compactreconstruction KW - Interfacialjumpintegration ER - TY - JOUR TI - Improvement of piezoelectric properties of relaxor type 0.695Pb(Mg1/3Nb2/3)O-3-0.305 PbTiO3 single crystal plate and silver vibrator by alternating current poling AU - Wang, Zhuangkai AU - Yamashita, Yohachi AU - Sun, Yiqin AU - Fujii, Tadashi AU - Karaki, Tomoaki T2 - JAPANESE JOURNAL OF APPLIED PHYSICS AB - Abstract Alternating current poling (ACP) and direct current poling (DCP) on [001]-oriented 0.695Pb(Mg 1/3 Nb 2/3 )O 3 −0.305PbTiO 3 (PMN-0.305PT) single crystal (SC) plates with a dimension of 12 × 4 × 0.3 mm and silver vibrators of 12 × 0.15 × 0.3 mm were investigated. The highest dielectric constant of 14500 and piezoelectric constant of 4200 pCN −1 were confirmed with the ACP SC plate manufactured by the conventional one charge Bridgman process. After array dicing into silver, the silver mode coupling coefficient k’ 33 = 94.3% was obtained from ACP SC. However, many spurious mode vibrations (SMV) were seen in the impedance spectra of the DCP and ACP SC silver vibrators. We consider that this SMV may be caused by array dicing damage. The PMN-0.305PT SC plate near the morphotropic phase boundary shows excellent piezoelectric and dielectric properties, however, these silvers tend to show SMV after dicing. This information is useful to select the PMN-PT composition for medical probe application. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.35848/1347-4065/ac7c52 VL - 61 IS - SN SP - SN - 1347-4065 KW - alternating current poling KW - relaxor ferroelectric single crystal KW - PMN-PT KW - silver vibrator ER - TY - JOUR TI - Hydrogen gas dispersion studies for hydrogen fuel cell vessels II: Fuel cell room releases and the influence of ventilation AU - Gitushi, K. M. AU - Blaylock, M. L. AU - Klebanoff, L. E. T2 - INTERNATIONAL JOURNAL OF HYDROGEN ENERGY AB - Results are presented for computational fluid dynamics (CFD) modeling for varying hydrogen leaks within a hydrogen vessel's Fuel Cell Rack inside a Fuel Cell Room. In the limiting case of no room ventilation, modeling shows that the flammable region produced by the hydrogen leak is initially limited by self-induced entrainment and recirculation of air caused by the buoyant rising of hydrogen. Locally and at shorter times (minutes), this effect can be even more influential in limiting the size of the flammable envelope than Fuel Cell Room ventilation. Interestingly, the more diffuse detectable (but sub-flammable) region is not self-limited. This indicates the recirculation pattern required for the self-limiting effect requires a sufficient concentration of hydrogen to establish and differentiate the rising hydrogen mass from the surrounding air, thereby establishing the recirculation pattern that self-limits the flammable region at short times. Modeling results with the Fuel Cell Room ventilation activated shows that several seconds after a hydrogen leak is initiated, the flammable region reaches a steady state, with only minor fluctuations due to the air currents created by ventilation. The expected trends with ventilation rate are found: for a given leak size, a decreasing flammable envelope is found as ventilation is increased and for a given level of ventilation, an increasing hydrogen leak rate produces a larger flammable region. For the cases and ventilation rates examined, flammable H2/air mixtures greater than 4% clear the Fuel Cell Room within 1.5 s after the hydrogen leak is turned off. The CFD modeling results for the detectable level of hydrogen that would trigger an alarm showed that higher ventilation rates might have the unintended consequence of making a hydrogen leak harder to detect, depending on the location of the gas detector in the Fuel Cell Room For the hydrogen leak rates considered in this study, we find that a ventilation rate of 15 ACH provides timely hydrogen evacuation while allowing the leak to be detected by the ceiling-mounted hydrogen monitor (for most monitor locations). DA - 2022/6/12/ PY - 2022/6/12/ DO - 10.1016/j.ijhydene.2022.04.263 VL - 47 IS - 50 SP - 21492-21505 SN - 1879-3487 KW - Hydrogen gas dispersion KW - Room ventilation KW - Hydrogen fuel cells KW - Hydrogen vessels KW - Hydrogen leak detection ER - TY - JOUR TI - Sensitivity analysis guided improvement of an electromyogram-driven lumped parameter musculoskeletal hand model AU - Hinson Jr, Robert Jr AU - Saul, Katherine AU - Kamper, Derek AU - Huang, He T2 - JOURNAL OF BIOMECHANICS AB - EMG-driven neuromusculoskeletal models have been used to study many impairments and hold great potential to facilitate human–machine interactions for rehabilitation. A challenge to successful clinical application is the need to optimize the model parameters to produce accurate kinematic predictions. In order to identify the key parameters, we used Monte-Carlo simulations to evaluate the sensitivities of wrist and metacarpophalangeal (MCP) flexion/extension prediction accuracies for an EMG-driven, lumped-parameter musculoskeletal model. Four muscles were modeled with 22 total optimizable parameters. Model predictions from EMG were compared with measured joint angles from 11 able-bodied subjects. While sensitivities varied by muscle, we determined muscle moment arms, maximum isometric force, and tendon slack length were highly influential, while passive stiffness and optimal fiber length were less influential. Removing the two least influential parameters from each muscle reduced the optimization search space from 22 to 14 parameters without significantly impacting prediction correlation (wrist: 0.90 ± 0.05 vs 0.90 ± 0.05, p = 0.96; MCP: 0.74 ± 0.20 vs 0.70 ± 0.23, p = 0.51) and normalized root mean square error (wrist: 0.18 ± 0.03 vs 0.19 ± 0.03, p = 0.16; MCP: 0.18 ± 0.06 vs 0.19 ± 0.06, p = 0.60). Additionally, we showed that wrist kinematic predictions were insensitive to parameters of the modeled MCP muscles. This allowed us to develop a novel optimization strategy that more reliably identified the optimal set of parameters for each subject (27.3 ± 19.5%) compared to the baseline optimization strategy (6.4 ± 8.1%; p = 0.004). This study demonstrated how sensitivity analyses can be used to guide model refinement and inform novel and improved optimization strategies, facilitating implementation of musculoskeletal models for clinical applications. DA - 2022/8// PY - 2022/8// DO - 10.1016/j.jbiomech.2022.111200 VL - 141 SP - SN - 1873-2380 KW - Musculoskeletal modeling KW - Optimization KW - Upper limb KW - Rehabilitation KW - Musculoskeletal modeling KW - Optimization KW - Upper limb KW - Rehabilitation ER - TY - JOUR TI - Evaluating anthropometric scaling of a generic adult model to represent pediatric shoulder strength AU - Dalman, Morgan AU - Liao, Ashlee AU - Saul, Katherine R. T2 - JOURNAL OF BIOMECHANICS AB - The structure of the developing musculoskeletal system during childhood and adolescence influences tissue loading and function. Anatomical features important for musculoskeletal loading such as muscle volume and limb proportion vary with age but limited available anatomical data for the developing limb makes predicting loads challenging. Our aim was to evaluate whether anthropometric scaling of an existing adult musculoskeletal upper limb model is sufficient to accurately represent pediatric strength. An adult upper limb model was scaled using two scale factors based on length features and max isometric force (MIF). Length features (e.g. limb and muscle length) were scaled based on linear regression for available literature reports of forearm length vs. height (N = 366 Pediatric, N = 107 Adults), while MIF was scaled based on relating body mass vs. total shoulder muscle volume (N = 6). Children-specific models were developed for 6 pediatric individuals whose height, body mass, and shoulder moment-generating capacity (a common measure of strength) were previously reported. These models were used to predict isometric shoulder moments for flexion/extension, internal/external rotation, and ad/abduction and compared with physical measurements previously reported. The predicted isometric shoulder moments were significantly correlated to measured moments for these same individuals (p < 0.04, r2 > 0.7). However, predicted moments tended to underestimate measured values; shoulder external rotation was most accurately predicted (slope: 1.1234) while shoulder adduction was most underestimated (slope: 0.4624). This work provides an initial basis for pediatric scaling but illustrates the important need for additional direct measures of muscle size and limb strength and function in a pediatric population. DA - 2022/8// PY - 2022/8// DO - 10.1016/j.jbiomech.2022.111170 VL - 141 SP - SN - 1873-2380 KW - Anthropometrics KW - Pediatric KW - Upper limb KW - Modeling KW - Shoulder KW - Anthropometrics KW - Pediatric KW - Upper limb KW - Modeling KW - Shoulder ER - TY - JOUR TI - Hidden damage visualization using laser speckle photometry AU - Welzen, J. AU - Yuan, F. G. AU - Fong, R. Y. T2 - NDT & E INTERNATIONAL AB - This paper exploits laser speckle photometry (LSP), a full-field non-contact optical-based image analysis technique, for effectively and rapidly imaging hidden damage in structures, rather than with the complex setups in digital speckle pattern interferometry (DSPI) or shearography (SG)-based interferometry. This technique will demonstrate a promising potential for large-area inspection of composite structures in near real time to unearth barely visible impact damage (BVID) which would typically go unnoticed during routine inspections. Three image (processing) algorithms for localizing and then imaging the BVID area were explored: conventional mean squared error (MSE), normalized cross-correlation (NCC), and an index-centered algorithm known as structural similarity index measure (SSIM). When implementing these algorithms in LSP, a pre-processing step of selecting a window size (subregion size) for locally correlating the images to localize the damage and estimate its size was performed as an advancement on the previous pixel-by-pixel correlations made with LSP. A trade-off strategy between two perceptual-based metrics, image fidelity and image sharpness/blurriness, was implemented to evaluate an appropriate range for window sizes followed by the image algorithms for creating high contrast imaging of damage regions. From the correlation map, the strategy was carried out to mitigate image noise caused by the camera (image) sensors and speckle patterns dictated by the overall root-mean-square deviation (RMSD) while maintaining a high level of sharpness characterized by the magnitude of the third-level discrete wavelet transform. The proposed image algorithms in conjunction with the appropriately selected window size served as imaging conditions in the context of laser speckles for the first time and were tested on BVID in an impacted honeycomb composite panel under thermal excitation. A low coherence (high-power) laser for fast screening of a large area, if required, followed by a high coherence (low-power laser) for detailed imaging were used to demonstrate the efficacy of LSP. The damage image region agreed well with a baseline image from the well-established point-by-point CT-scan with all the three image algorithms. Overall, NCC and SSIM performed slightly better than MSE, with SSIM generally being the better of the two. Nevertheless, MSE has its merits with ease of interpretation and implementation. LSP with the proposed imaging conditions shows enormous potential as a real-time non-destructive inspection (NDI) technique not only in the aerospace industry but also in industries such as additive manufacturing where on-line in-situ monitoring is desired for prevalent defects. The real-time inspection using LSP will further allow immediate feedback for process controls. DA - 2022/10// PY - 2022/10// DO - 10.1016/j.ndteint.2022.102700 VL - 131 SP - SN - 1879-1174 UR - http://dx.doi.org/10.1016/j.ndteint.2022.102700 KW - Laser speckle photometry KW - Barely visible impact damage KW - Mean squared error KW - Normalized cross correlation KW - Structural similarity index measure KW - Honeycomb composite panel KW - Optimized window size ER - TY - JOUR TI - Editorial: Next Generation User-Adaptive Wearable Robots AU - Bulea, Thomas C. AU - Sharma, Nitin AU - Sikdar, Siddhartha AU - Su, Hao T2 - FRONTIERS IN ROBOTICS AND AI AB - EDITORIAL article Front. Robot. AI, 22 June 2022Sec. Biomedical Robotics https://doi.org/10.3389/frobt.2022.920655 DA - 2022/6/22/ PY - 2022/6/22/ DO - 10.3389/frobt.2022.920655 VL - 9 SP - SN - 2296-9144 KW - exoskeleton KW - wearable robot KW - rehabilitation KW - human-in-the loop KW - functional electric stimulation ER - TY - JOUR TI - Can the lack of fibrillar form of alpha-synuclein in Lewy bodies be explained by its catalytic activity? AU - Kuznetsov, Ivan A. AU - Kuznetsov, Andrey V T2 - MATHEMATICAL BIOSCIENCES AB - Finding the causative pathophysiological mechanisms for Parkinson’s disease (PD) is important for developing therapeutic interventions. Until recently, it was believed that Lewy bodies (LBs), the hallmark of PD, are mostly composed of alpha-synuclein (α-syn) fibrils. Recent results (Shahmoradian et al. (2019)) demonstrated that the fibrillar form of α-syn is lacking from LBs. Here we propose that this surprising observation can be explained by the catalytic activity of the fibrillar form of α-syn. We assumed that α-syn fibrils catalyze the formation of LBs, but do not become part of them. We developed a mathematical model based on this hypothesis. By using the developed model, we investigated the consequences of this hypothesis. In particular, the model suggests that the long incubation time of PD can be explained by a two-step aggregation process that leads to its development: (i) aggregation of monomeric α-syn into α-syn oligomers and fibrils and (ii) clustering of membrane-bound organelles, which may cause disruption of axonal trafficking and lead to neuron starvation and death. The model shows that decreasing the rate of destruction of α-syn aggregates in somatic lysosomes accelerates the formation of LBs. Another consequence of the model is the prediction that removing α-syn aggregates from the brain after the aggregation of membrane-bound organelles into LBs has started may not stop the progression of PD because LB formation is an autocatalytic process; hence, the formation of LBs will be catalyzed by aggregates of membrane-bound organelles even in the absence of α-syn aggregates. The performed sensitivity study made it possible to establish the hierarchy of model parameters with respect to their effect on the formation of vesicle aggregates in the soma. DA - 2022/2// PY - 2022/2// DO - 10.1016/j.mbs.2021.108754 VL - 344 SP - SN - 1879-3134 KW - Neuron KW - Axon KW - Parkinson's disease KW - Mathematical modeling KW - Alpha-synuclein ER - TY - JOUR TI - Sparsifying the resolvent forcing mode via gradient-based optimisation AU - Skene, Calum S. AU - Yeh, Chi-An AU - Schmid, Peter J. AU - Taira, Kunihiko T2 - JOURNAL OF FLUID MECHANICS AB - We consider the use of sparsity-promoting norms in obtaining localised forcing structures from resolvent analysis. By formulating the optimal forcing problem as a Riemannian optimisation, we are able to maximise cost functionals whilst maintaining a unit-energy forcing. Taking the cost functional to be the energy norm of the driven response results in a traditional resolvent analysis and is solvable by a singular value decomposition (SVD). By modifying this cost functional with the $L_1$ -norm, we target spatially localised structures that provide an efficient amplification in the energy of the response. We showcase this optimisation procedure on two flows: plane Poiseuille flow at Reynolds number $Re=4000$ , and turbulent flow past a NACA 0012 aerofoil at $Re=23\,000$ . In both cases, the optimisation yields sparse forcing modes that maintain important features of the structures arising from an SVD in order to provide a gain in energy. These results showcase the benefits of utilising a sparsity-promoting resolvent formulation to uncover sparse forcings, specifically with a view to using them as actuation locations for flow control. DA - 2022/7/6/ PY - 2022/7/6/ DO - 10.1017/jfm.2022.519 VL - 944 SP - SN - 1469-7645 KW - shear-flow instability KW - instability control ER - TY - JOUR TI - Low-Order Modeling of Wingtip Vortices in a Vortex Lattice Method AU - Loewenthal, Ethan AU - Gopalarathnam, Ashok T2 - AIAA JOURNAL AB - Wingtip-flow effects on the aerodynamic forces and moments of a wing become increasingly significant as the aspect ratio decreases. These effects are dominated by the tip vortex and an associated suction zone, which results in a supplementary “vortex lift” that is not captured by conventional vortex lattice methods (VLMs). Although many augmented VLMs have addressed such free-vortical flows on the leading edges of delta wings and even wingtips, they do not account for the portion of the vorticity that may be supported by the attached flow at the tip. The current work consists of an augmented VLM designed to capture the geometry and strength of the free tip vortex along the wingtip, and it is distinguished from prior models by the capability to allocate vorticity between the bound wingtip flow and the free tip-vortex flow at each chordwise position. This paper presents the model and its predictions of tip-vortex positions, as well as forces and moments on low-aspect-ratio wings. The model demonstrates lift distributions typical of vortex lift, promising agreement with forces and moments from experimental work as well as modulation of the forces and moments by selection of the maximum allowable bound vorticity along the tips. DA - 2022/3// PY - 2022/3// DO - 10.2514/1.J060654 VL - 60 IS - 3 SP - 1708-1720 SN - 1533-385X ER - TY - JOUR TI - Effects of subject-variability on nasally inhaled drug deposition, uptake, and clearance AU - Chari, Sriram AU - Sridhar, Karthik AU - Kleinstreuer, Clement T2 - JOURNAL OF AEROSOL SCIENCE AB - Accurate and realistic predictions of the fate of nasally inhaled generic drugs provide new physical insight which can be of great importance to toxicologists, drug developers and federal regulators alike. To understand the dynamics of mucociliary clearance (MCC) and subsequent absorption of the dissolved drug by the nasal epithelium, it becomes necessary to model the air-particle-mucus dynamics accurately. The MCC process, including particle dissolution, transport and absorption for a 3-D representative nasal cavity, were established by Chari et al. (2021). In this study, the effects of inter-subject variability of three representative nasal cavities (subjects A, B, C) on deposition and subsequent uptake of the dissolved drug in the nasal epithelium are analyzed for three generic drugs: Mometasone furoate (MF), Flunisolide (FN), and Ribavirin (RB). The computational fluid-particle dynamics (CF-PD) results indicate that smaller sized particles (3 μm) deposit more in the ciliated portion of the nasal cavity where the columnar cells responsible for uptake are present. In contrast, larger particles (10 μm) tend to deposit in the unciliated anterior third of the nose. The epithelial uptake in case of subject A was considerably higher than that in subjects B and C because of the unique anatomical characteristics of subject A. Also, FN and RB were found to have a higher rate of uptake compared to MF due to their considerably higher partition coefficient. As a visualization tool, concentration contours are used to explain regional trends in cumulative drug uptake for all three cases. • The open-source CFD toolbox, OpenFOAM, has been employed for the development of the computer simulation model. • This study illustrates the effects of inter-subject variability on deposition, dissolution and uptake of 3 generic drugs in representative nasal cavity models. • Smaller particles, with their relatively large surface area, tend to dissolve quicker and are absorbed more rapidly than larger particles. • Particles deposited closer to the ciliated portion of the nasal cavity are more readily absorbed when compared to particles deposited closer to the unciliated nasal vestibule. DA - 2022/9// PY - 2022/9// DO - 10.1016/j.jaerosci.2022.106021 VL - 165 SP - SN - 1879-1964 KW - Nasal geometric variabilities KW - CF-PD analysis With updated OpenFOAM KW - solver KW - Inhaled drug-aerosol transport and uptake KW - Mucus layer dynamics KW - Mucociliary clearance KW - Dissolution and absorption of three generic KW - drugs ER - TY - JOUR TI - The pendulum adaptive frequency oscillator AU - Li, XiaoFu AU - Kallepalli, Pawan AU - Mollik, Tushar AU - Ul Shougat, Md Raf E AU - Kennedy, Scott AU - Frabitore, Sean AU - Perkins, Edmon T2 - Mechanical Systems and Signal Processing AB - Adaptive oscillators are a type of nonlinear oscillator that are capable of learning and storing information in plastic states. Here, a typical mechanical pendulum is modified to have an adjustable rod length to create a pendulum adaptive frequency oscillator. Since the resonance frequency of the pendulum is a function of the rod length, this allows the pendulum to learn and encode frequency information from an external source. An experimental pendulum adaptive frequency oscillator is designed and constructed, and its performance is compared to numerical simulations. This nonlinear pendulum was approximated as a Duffing oscillator through the method of multiple scales to determine the physical constants of the experiment by using a curve fit. Utilizing the pendulum adaptive frequency oscillator’s dynamics, this system is able to learn a resonance condition and store this information in the rod length. This causes the system to seek resonance, even with considerable nonlinearity. As pendulums can be used to harvest energy, this type of adaptation could be used to further exploit vibratory energy sources. DA - 2022/11/1/ PY - 2022/11/1/ DO - 10.1016/j.ymssp.2022.109361 VL - 179 SP - 109361 SN - 1096-1216 KW - Adaptive oscillators KW - Pendulum KW - Duffing oscillator KW - Electromechanical system ER - TY - JOUR TI - Finite element study of the impact of pedicle screw density on the biomechanical response of a Lenke 1AN scoliotic curve AU - Warren, Justin M. AU - Hey, Lloyd A. AU - Mazzoleni, Andre P. T2 - JOURNAL OF ORTHOPAEDICS AB - Benefits of increasing screw density in posterior instrumentation used to treat a scoliotic deformity are demonstrated using a three-dimensional finite element model (FEM) of the thoracolumbosacral spine. The FEM represents a Lenke 1AN scoliotic deformity with a 50° Cobb angle and 20° apical vertebral rotation. The curve is corrected with bilateral pedicle screw fixation and 75 separate randomized screw distributions. Total construct screw density, concave rod screw locations at T6, T10, T11 and T12, and convex rod screw locations at T7 and T12 each correlate strongly with reductions in postoperative Cobb angle (P < 0.05). Apical vertebral rotation is greatly impacted (reduced) by screws placed at the apical vertebra on both concave and convex rods (P < 0.05). Under pure moment loading, intersegmental micromotion is generally reduced when motion segment screw density is increased, with the exception being the upper instrumented joint. These results suggest that increasing the screw density of posterior constructs used to treat a Lenke 1AN scoliotic deformity may improve the de-rotation correction with better postural restoration, reducing the risk of future complications including pseudarthrosis. DA - 2022/// PY - 2022/// DO - 10.1016/j.jor.2022.05.012 VL - 32 SP - 92-97 SN - 0972-978X KW - Finite element analysis KW - Scoliosis KW - Pedicle screw KW - Micromotion ER - TY - JOUR TI - Silver Nanowire Composite Electrode Enabling Highly Flexible, Robust Organic Photovoltaics AU - Booth, Ronald E. AU - Schrickx, Harry M. AU - Hanby, Georgia AU - Liu, Yuxuan AU - Qin, Yunpeng AU - Ade, Harald AU - Zhu, Yong AU - Brendan T. O'Connor, T2 - SOLAR RRL AB - Using Ag nanowires (NWs) is a promising approach to make flexible and transparent conducting electrodes for organic photovoltaics (OPVs). However, the roughness of the NWs can decrease device performance. Herein, a Ag NW electrode embedded in a UV‐curable epoxy that uses a simple mechanical lift‐off process resulting in highly planar electrodes is demonstrated. A bimodal blend of Ag NWs with varying aspect ratios is used to optimize the transparency and conductivity of the electrode. In addition, a ZnO layer is coated on the Ag NWs prior to the embedding process to ensure low contact resistance in the OPV cells. The resulting resin‐embedded ZnO‐encapsulated silver nanowire (REZEN) electrode is found to have excellent mechanical stability. REZEN electrode‐based OPV cells exhibit comparable performance with reference devices, achieving maximum power conversion efficiency (PCE) of 13.5% and 13.6% respectively. The REZEN‐based OPV cells are also mechanically robust, retaining 97% of their PCE after 5000 cycles at R = 1.2 mm and 94% PCE after 1000 cycles at R = 0.55 mm. This flexibility is among the highest reported for freestanding devices. Thus, the REZEN electrode is a promising and simple strategy to achieve mechanically robust ITO‐free flexible OPV cells. DA - 2022/6/15/ PY - 2022/6/15/ DO - 10.1002/solr.202200264 SP - SN - 2367-198X KW - flexible organic photovoltaics KW - flexible transparent electrodes KW - mechanically stable organic photovoltaics KW - organic solar cells KW - silver nanowire electrodes ER - TY - JOUR TI - Design and Backdrivability Modeling of a Portable High Torque Robotic Knee Prosthesis With Intrinsic Compliance for Agile Activities AU - Zhu, Junxi AU - Jiao, Chunhai AU - Dominguez, Israel AU - Yu, Shuangyue AU - Su, Hao T2 - IEEE-ASME TRANSACTIONS ON MECHATRONICS AB - High-performance prostheses are crucial to enable versatile activities like walking, squatting, and running for lower extremity amputees. State-of-the-art prostheses are either not powerful enough to support demanding activities or have low compliance (low backdrivability) due to the use of high speed ratio transmission. Besides speed ratio, gearbox design is also crucial to the compliance of wearable robots, but its role is typically ignored in the design process. This paper proposed an analytical backdrive torque model that accurately estimate the backdrive torque from both motor and transmission to inform the robot design. Following this model, this paper also proposed methods for gear transmission design to improve compliance by reducing inertia of the knee prosthesis. We developed a knee prosthesis using a high torque actuator (built-in 9:1 planetary gear) with a customized 4:1 low-inertia planetary gearbox. Benchtop experiments show the backdrive torque model is accurate and proposed prosthesis can produce 200 Nm high peak torque (shield temperature <60°C), high compliance (2.6 Nm backdrive torque), and high control accuracy (2.7/8.1/1.7 Nm RMS tracking errors for 1.25 m/s walking, 2 m/s running, and 0.25 Hz squatting, that are 5.4%/4.1%/1.4% of desired peak torques). Three able-bodied subject experiments showed our prosthesis could support agile and high-demanding activities. DA - 2022/6/3/ PY - 2022/6/3/ DO - 10.1109/TMECH.2022.3176255 VL - 6 SP - SN - 1941-014X UR - http://dx.doi.org/10.1109/tmech.2022.3176255 KW - Torque KW - Brushless DC motors KW - Actuators KW - Gears KW - Prosthetics KW - Robots KW - Rotors KW - Backdrive torque modeling KW - high compliance KW - high torque actuator KW - powered prosthesis KW - wearable robots ER - TY - JOUR TI - Using ultrasonic attenuation in cortical bone to infer distributions on pore size AU - White, R. D. AU - Alexanderian, A. AU - Yousefian, O. AU - Karbalaeisadegh, Y. AU - Bekele-Maxwell, K. AU - Kasali, A. AU - Banks, H. T. AU - Talmant, M. AU - Grimal, Q. AU - Muller, M. T2 - APPLIED MATHEMATICAL MODELLING AB - In this work we infer the underlying distribution on pore radius in human cortical bone samples using ultrasonic attenuation data. We first discuss how to formulate polydisperse attenuation models using a probabilistic approach and the Waterman Truell model for scattering attenuation. We then compare the Independent Scattering Approximation and the higher-order Waterman Truell models’ forward predictions for total attenuation in polydisperse samples. Following this, we formulate an inverse problem under the Prohorov Metric Framework coupled with variational regularization to stabilize this inverse problem. We then use experimental attenuation data taken from human cadaver samples and solve inverse problems resulting in nonparametric estimates of the probability density function on pore radius. We compare these estimates to the “true” microstructure of the bone samples determined via microCT imaging. We find that our methodology allows us to reliably estimate the underlying microstructure of the bone from attenuation data. DA - 2022/9// PY - 2022/9// DO - 10.1016/j.apm.2022.05.024 VL - 109 SP - 819-832 SN - 1872-8480 KW - Ultrasound KW - Cortical bone KW - Polydisperse KW - Waterman truell KW - Inverse problems KW - Variational regularization ER - TY - JOUR TI - A Fused Gaussian Process Modeling and Model Predictive Control Framework for Real-Time Path Adaptation of an Airborne Wind Energy System AU - Siddiqui, Ayaz AU - Borek, John AU - Vermillion, Chris T2 - IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY AB - This article presents a computationally tractable adaptive control strategy suitable for mobile systems operating in a stochastically and spatiotemporally varying environment by fusing Gaussian process modeling and receding horizon control. This strategy ideally manages the tradeoff between exploration (maintaining an accurate estimate of the stochastic resource) and exploitation (maximizing a performance index, which generally consists of harvesting the resource) subject to partial observability (stochastic resource only measurable at the system’s location) and mobility constraints, which are characteristic of dynamic systems. The case study in this article focuses on a crosswind airborne wind energy (AWE) system where the wind turbine tower is replaced by tethers and a lifting body, allowing the system to adjust its altitude, with the goal of operating at the altitude that maximizes net energy production in a wind environment that is changing in altitude and time. Real wind speed versus altitude data has been used to validate the strategy and results are presented for a variety of control strategies applied to a rigid wing-based AWE system. DA - 2022/6/6/ PY - 2022/6/6/ DO - 10.1109/TCST.2022.3178038 SP - SN - 1558-0865 KW - Wind speed KW - Wind power generation KW - Real-time systems KW - Optimization KW - Gaussian processes KW - Adaptation models KW - Wind turbines KW - Adaptive control KW - stochastic processes KW - and wind energy generation ER - TY - JOUR TI - POLYVINYL ALCOHOL CRYOGELS FOR ACOUSTIC CHARACTERIZATION OF PHASE-CHANGE CONTRAST AGENTS AU - Durham, Phillip G. AU - Kim, Jinwook AU - Eltz, Katherine M. AU - Caskey, Charles F. AU - Dayton, Paul A. T2 - ULTRASOUND IN MEDICINE AND BIOLOGY AB - Phase-change contrast agents (PCCAs) consisting of lipid-encapsulated low-boiling-point perfluorocarbons can be used in conjunction with ultrasound for diagnostic and therapeutic applications. One benefit of PCCAs is site-specific activation, whereby the liquid core is acoustically vaporized into a bubble detectable via ultrasound imaging. For further evaluation of PCCAs in a variety of applications, it is useful to disperse these nanodroplets into an acoustically compatible stationary matrix. However, many traditional phantom preparations require heating, which causes premature thermal activation of low-boiling-point PCCAs. Polyvinyl alcohol (PVA) cryogels do not require heat to set. Here we propose a simple method for the incorporation of the low-boiling-point PCCAs using octafluoropropane (OFP) and decafluorobutane (DFB) into PVA cryogels for a variety of acoustic characterization applications. We determined the utility of the phantoms by activating droplets with a focused transducer, visualizing the lesions with ultrasound imaging. At 1 MHz, droplet activation was consistently observed at 2.0 and 4.0 MPa for OFP and DFB, respectively. DA - 2022/5// PY - 2022/5// DO - 10.1016/j.ultrasmedbio.2022.01.007 VL - 48 IS - 5 SP - 954-960 SN - 1879-291X KW - Phase-change contrast agent KW - Nanodroplets KW - Polyvinyl alcohol cryogel ER - TY - JOUR TI - Development of Viscoelastic Damper Based on NBR and Organic Small-Molecule Composites AU - Ge, Teng AU - Xu, Zhao-Dong AU - Yuan, Fuh-Gwo T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - Viscoelastic (VE) damper is usually vulcanized by mixing polymer matrix, additives, and fillers, all of which have a great influence on the viscoelastic response of the material. In this study, a series of novel samples of VE materials have been produced by adding different kinds and amounts of organic small molecule modifiers (AO1035, AO60, and AO80) to neat nitrile-butadiene rubber (NBR). The mechanical properties of VE materials have been tested on a dynamic mechanical analyzer and universal testing tensile machine, and the most excellent formulation was selected for manufacturing VE damper. The dynamic mechanical properties of the VE material in the damper with amplitude and frequency are tested and analyzed. The results indicate that the VE damper has a high energy dissipation capacity. To clarify the dynamic mechanical properties of the novel VE material, a high-order fractional derivative model is proposed, which considers the effects of amplitude and frequency simultaneously based on the energy dissipation mechanism of the novel VE material. Finally, the calculated results using this model are compared with the tested data, which has verified the correctness of the mathematical model. DA - 2022/8/1/ PY - 2022/8/1/ DO - 10.1061/(ASCE)MT.1943-5533.0004339 VL - 34 IS - 8 SP - SN - 1943-5533 KW - Viscoelastic (VE) material KW - Performance tests KW - Energy dissipation mechanism KW - Hydrogen bonds KW - Mathematical model ER - TY - JOUR TI - No ball milling nee de d: Alternative ODS steel manufacturing with gas atomization reaction synthesis (GARS) and friction-based processing AU - Zhang, D. AU - Darsell, J. T. AU - Wang, J. AU - Ma, X. AU - Grant, G. J. AU - Anderson, I. E. AU - Rieken, J. R. AU - Edwards, D. J. AU - Setyawan, W. AU - Horn, T. J. AU - Odette, G. R. T2 - JOURNAL OF NUCLEAR MATERIALS AB - Oxide dispersion strengthened (ODS) steels are promising structural materials for future fusion reactors. The high-density (∼1023/m3) of highly stable Y-(Ti)-O nano-oxides provide high sink strength for radiation resistance and high-temperature (> 650 °C) creep strength. Concomitantly, helium management is enabled by trapping high density (∼1023/m3) of small (< 3 nm) helium bubbles in the vicinity of nano-oxides. However, conventional route of making ODS steels involves prolonged ball milling, canning, degassing, and laborious thermo-mechanical processing (TMP). Such route, especially the batch-by-batch ball milling step, faces persistent challenge with scalability and high costs. Gas atomization reaction synthesis (GARS) method has demonstrated the potential of making precursor ODS steel powders without ball milling, but the nano-oxide density was around 1021/m3 in the final consolidated form by conventional TMP. Taking advantage of GARS precursor powder, we use friction-based processing, including friction consolidation and extrusion, to manufacture ODS steel with further improved nano-oxide characteristics. Preliminary results showed that Y/Ti/O species were intimately mixed and rapidly reacted to form nano-oxides with a number density of ∼1022/m3. DA - 2022/8/1/ PY - 2022/8/1/ DO - 10.1016/j.jnucmat.2022.153768 VL - 566 SP - SN - 1873-4820 KW - ODS Steel KW - Gas Atomization Reaction Synthesis KW - Friction Consolidation and Extrusion KW - Electron Microscopy KW - Atom Probe Tomography ER - TY - JOUR TI - Multiscale and multiphysics FEA simulation and materials optimization for laser ultrasound transducers AU - Liu, Sipan AU - Kim, Howuk AU - Huang, Wenbin AU - Chang, Wei-Yi AU - Jiang, Xiaoning AU - Ryu, Jong Eun T2 - MATERIALS TODAY COMMUNICATIONS AB - The relationship between the nanocomposite design and the laser ultrasound transducer (LUT) characteristics was investigated through simulations in multiple scale levels for material behavior, device response, and acoustic wave propagation in media. First, the effects of the nanoparticle size and concentration on the effective properties of composites were quantitatively investigated with the finite element analysis (FEA) method. Second, the effective properties of the nanocomposite were assigned to the layer, which is modeled as a homogeneous material, in the FEA for the LUT simulating the energy conversion from the incident laser to the acoustic wave. Finally, the ultrasound propagation in the water was calculated by a theoretical wave propagation model. The FEA-based prediction was compared with the experimental data in the literature and a theoretical analysis for LUT based on Thermal-Acoustic coupling. As a result, the ultrasound waves on the transducer surface and at a distance in the water could be predicted. Based on the hierarchically integrated prediction procedure, the optimal conditions of the photoacoustic nanocomposites were investigated through the parametric study with the particle size and concentration as variables. The results guide the material designs optimized for different device characteristics, such as high pressure and broad bandwidth. DA - 2022/6// PY - 2022/6// DO - 10.1016/j.mtcomm.2022.103599 VL - 31 SP - SN - 2352-4928 UR - http://dx.doi.org/10.1016/j.mtcomm.2022.103599 KW - Polymer-matrix composites (PMCs) KW - Finite element analysis (FEA) KW - Multiscale modeling KW - Acoustic emission KW - Laser ultrasound transducer ER - TY - JOUR TI - Phylogeny-guided microbiome OTU-specific association test (POST) AU - Huang, Caizhi AU - Callahan, Benjamin John AU - Wu, Michael C. AU - Holloway, Shannon T. AU - Brochu, Hayden AU - Lu, Wenbin AU - Peng, Xinxia AU - Tzeng, Jung-Ying T2 - MICROBIOME AB - The relationship between host conditions and microbiome profiles, typically characterized by operational taxonomic units (OTUs), contains important information about the microbial role in human health. Traditional association testing frameworks are challenged by the high dimensionality and sparsity of typical microbiome profiles. Phylogenetic information is often incorporated to address these challenges with the assumption that evolutionarily similar taxa tend to behave similarly. However, this assumption may not always be valid due to the complex effects of microbes, and phylogenetic information should be incorporated in a data-supervised fashion.In this work, we propose a local collapsing test called phylogeny-guided microbiome OTU-specific association test (POST). In POST, whether or not to borrow information and how much information to borrow from the neighboring OTUs in the phylogenetic tree are supervised by phylogenetic distance and the outcome-OTU association. POST is constructed under the kernel machine framework to accommodate complex OTU effects and extends kernel machine microbiome tests from community level to OTU level. Using simulation studies, we show that when the phylogenetic tree is informative, POST has better performance than existing OTU-level association tests. When the phylogenetic tree is not informative, POST achieves similar performance as existing methods. Finally, in real data applications on bacterial vaginosis and on preterm birth, we find that POST can identify similar or more outcome-associated OTUs that are of biological relevance compared to existing methods.Using POST, we show that adaptively leveraging the phylogenetic information can enhance the selection performance of associated microbiome features by improving the overall true-positive and false-positive detection. We developed a user friendly R package POSTm which is freely available on CRAN ( https://CRAN.R-project.org/package=POSTm ). Video Abstract. DA - 2022/6/7/ PY - 2022/6/7/ DO - 10.1186/s40168-022-01266-3 VL - 10 IS - 1 SP - SN - 2049-2618 KW - Association test KW - Phylogenetic tree KW - Kernel machine regression ER - TY - JOUR TI - Modeling and Stiffness-Based Continuous Torque Control of Lightweight Quasi-Direct-Drive Knee Exoskeletons for Versatile Walking Assistance AU - Huang, Tzu-Hao AU - Zhang, Sainan AU - Yu, Shuangyue AU - MacLean, Mhairi K. AU - Zhu, Junxi AU - Di Lallo, Antonio AU - Jiao, Chunhai AU - Bulea, Thomas C. AU - Zheng, Minghui AU - Su, Hao T2 - IEEE TRANSACTIONS ON ROBOTICS AB - State-of-the-art exoskeletons are typically limited by low control bandwidth and small range stiffness of actuators which are based on high gear ratios and elastic components (e.g., series elastic actuators). Furthermore, most exoskeletons are based on discrete gait phase detection and/or discrete stiffness control resulting in discontinuous torque profiles. To fill these two gaps, we developed a portable lightweight knee exoskeleton using quasi-direct drive (QDD) actuation that provides 14 Nm torque (36.8% biological joint moment for overground walking). This paper presents 1) stiffness modeling of torque-controlled QDD exoskeletons and 2) stiffness-based continuous torque controller that estimates knee joint moment in real-time. Experimental tests found the exoskeleton had high bandwidth of stiffness control (16 Hz under 100 Nm/rad) and high torque tracking accuracy with 0.34 Nm Root Mean Square (RMS) error (6.22%) across 0-350 Nm/rad large range stiffness. The continuous controller was able to estimate knee moments accurately and smoothly for three walking speeds and their transitions. Experimental results with 8 able-bodied subjects demonstrated that our exoskeleton was able to reduce the muscle activities of all 8 measured knee and ankle muscles by 8.60%-15.22% relative to unpowered condition, and two knee flexors and one ankle plantar flexor by 1.92%-10.24% relative to baseline (no exoskeleton) condition. DA - 2022/6// PY - 2022/6// DO - 10.1109/TRO.2022.3170287 VL - 38 IS - 3 SP - 1442-1459 SN - 1941-0468 KW - Knee KW - Exoskeletons KW - Torque KW - Legged locomotion KW - Actuators KW - Biomechanics KW - Muscles KW - Force KW - torque control KW - knee exoskeleton KW - quasi-direct-drive actuation KW - stiffness control ER - TY - JOUR TI - Integrating charge mobility, stability and stretchability within conjugated polymer films for stretchable multifunctional sensors AU - Son, Sung Yun AU - Lee, Giwon AU - Wang, Hongyu AU - Samson, Stephanie AU - Wei, Qingshan AU - Zhu, Yong AU - You, Wei T2 - NATURE COMMUNICATIONS AB - Conjugated polymers (CPs) are promising semiconductors for intrinsically stretchable electronic devices. Ideally, such CPs should exhibit high charge mobility, excellent stability, and high stretchability. However, converging all these desirable properties in CPs has not been achieved via molecular design and/or device engineering. This work details the design, synthesis and characterization of a random polythiophene (RP-T50) containing ~50 mol% of thiophene units with a thermocleavable tertiary ester side chain and ~50 mol% of unsubstituted thiophene units, which, upon thermocleavage of alkyl chains, shows significant improvement of charge mobility and stability. Thermal annealing a RP-T50 film coated on a stretchable polydimethylsiloxane substrate spontaneously generates wrinkling in the polymer film, which effectively enhances the stretchability of the polymer film. The wrinkled RP-T50-based stretchable sensors can effectively detect humidity, ethanol, temperature and light even under 50% uniaxial and 30% biaxial strains. Our discoveries offer new design rationale of strategically applying CPs to intrinsically stretchable electronic systems. DA - 2022/5/18/ PY - 2022/5/18/ DO - 10.1038/s41467-022-30361-0 VL - 13 IS - 1 SP - SN - 2041-1723 ER - TY - JOUR TI - Numerical simulation of stable and unstable ram-mode operation of an axisymmetric ethylene-fueled inlet-isolator-combustor configuration AU - Hash, Caleb A. AU - Drummond, Paige M. AU - Edwards, Jack R. AU - Kato, Nozomu AU - Lee, Tonghun T2 - COMBUSTION AND FLAME AB - Large-eddy simulations of stable and unstable ramjet operational modes are presented for an axisymmetric inlet-isolator-combustor configuration experimentally tested in the University of Illinois's ACT-II arc-heated combustion tunnel. A 32 species ethylene oxidation mechanism including nitrous oxide formation reactions is used in the calculations (HyChem FFCM 2.0). Conjugate heat-transfer models based on an assumed penetration depth of the applied heating load are used to account for localized wall heating during the short durations (∼0.2 to 0.3 s) of the parts of the experiments simulated in this work. The results show a marked sensitivity to trace levels of atomic oxygen (∼1% by mass) in the free stream, a consequence of the arc-heating process. Atomic oxygen significantly reduces ignition delay at the relatively low pressures present within the configuration. With 1% atomic oxygen in the free stream, a jet-wake stabilized, partially-premixed flame structure emerges during thermal-throat ramjet operation at an equivalence ratio of 1.24, in accord with available experimental pressure and imaging measurements. Considering the free stream as pure air results in a cavity-wake stabilized, rich premixed flame. Simulations of unstable ram-mode operation leading to inlet unstart at an equivalence ratio of 1.97 also indicate a sensitivity to the free-stream composition. A reduction in atomic oxygen concentration to 0.8% by mass yields good agreement with the experimentally-observed isolator shock-train propagation speed. Both the computational and experimental results indicate that the shock train accelerates before being disgorged from the inlet. This acceleration stems from a rapid increase in the sizes of regions of low speed, sometimes separated flow behind Mach disks that form as the shock train proceeds upstream. DA - 2022/8// PY - 2022/8// DO - 10.1016/j.combustflame.2022.112157 VL - 242 SP - SN - 1556-2921 KW - Large eddy simulation KW - Partially-premixed combustion KW - Isolator shock train KW - Thermal-throat ramjet ER - TY - JOUR TI - Prediction of pore-scale-property dependent natural convection in porous media at high Rayleigh numbers AU - Gasow, Stefan AU - Kuznetsov, Andrey V. AU - Jin, Yan T2 - INTERNATIONAL JOURNAL OF THERMAL SCIENCES AB - Natural convection in porous media has received increasing attention in recent years due to its significance in engineering applications. This process is traditionally analyzed by the solution of the classical Darcy-Oberbeck-Boussinesq (DOB) equations. According to the DOB equations, natural convection in porous media is exclusively dependent on the Rayleigh-Darcy number, Ra, while the Sherwood number, Sh, has a linear relationship with Ra at high Rayleigh numbers. However, these predictions conflict with experimental observations. In this study, we have performed a pore-scale resolved direct numerical simulation (DNS) study of natural convection in periodic porous media composed of two-dimensional square and circular obstacles. Based on our analysis, a new correlation of Sh for large Rayleigh numbers (Ra≥1000), low Darcy numbers Da, and high Schmidt numbers Sc (Da/Sc≤2×10−8) has been proposed, expressed as Sh=aRa1−0.2φ2+1, where a=0.011±0.002 is a pore-scale geometric parameter. The new correlation has been validated over a wide range of Rayleigh numbers, porosity values, and pore-scale geometries. Our DNS results also show that, with a decrease of porosity, it becomes more difficult for mega-plumes with low wavenumbers to enter the boundary layer. Low wavenumber motions decay much faster with a decrease of Da than the pore-scale motions near the wall. The volume-averaged dissipation rate nondimensionalized using the pore size εˆi has the scaling law εˆi∼Da in the internal region and εˆi∼Da1/2 in the near-wall region. We expect that these characteristics obtained from DNS also apply to natural convection in porous media with much lower Darcy numbers. DA - 2022/9// PY - 2022/9// DO - 10.1016/j.ijthermalsci.2022.107635 VL - 179 SP - SN - 1778-4166 KW - Porous media KW - Natural convection KW - Mass transfer KW - Direct numerical simulation KW - Macroscopic modeling ER - TY - JOUR TI - On-Demand Solar and Thermal RadiationManagement Based on Switchable Interwoven Surfaces AU - Ke, Yujie AU - Li, Yanbin AU - Wu, Lichen AU - Wang, Shancheng AU - Yang, Ronggui AU - Yin, Jie AU - Tan, Gang AU - Long, Yi T2 - ACS ENERGY LETTERS AB - On-demand and selective regulation of the radiative cooling (long-wave infrared, LWIR) and solar heat gain (ultraviolet-, visible- and near-IR, UV–vis–NIR) of building facades is a grand challenge but essential to decrease energy usage in buildings. Here, we report a reconfigurable interwoven surface that can dynamically switch the overlapping sequence to achieve spectral selectivity and ultrabroadband modulations for windows, walls/roofs with decent spectral modulations, and energy-saving performance. The result surpasses the best reported passive radiative cooling smart windows with a more than doubled visible transmittance (Tlum = 0.50) and LWIR modulation (Δ εLWIR = 0.57). Our energy-saving samples outperform the commercial building materials across climate zones 2–6. This design principle is scalable and applicable for diverse materials, interwoven structures, and 2D-3D surfaces, which provide a strategy to give programmable heating/cooling modulations in various applications. DA - 2022/5/13/ PY - 2022/5/13/ DO - 10.1021/acsenergylett.2c00419 VL - 7 IS - 5 SP - 1758-1763 SN - 2380-8195 ER - TY - JOUR TI - Estimation of Thickness and Speed of Sound for Transverse Cortical Bone Imaging Using Phase Aberration Correction Methods: An In Silico and Ex Vivo Validation Study AU - Minh, Huong Nguyen AU - Muller, Marie AU - Raum, Kay T2 - APPLIED SCIENCES-BASEL AB - Delay-and-sum (DAS) beamforming of backscattered echoes is used for conventional ultrasound imaging. Although DAS beamforming is well suited for imaging in soft tissues, refraction, scattering, and absorption, porous mineralized tissues cause phase aberrations of reflected echoes and subsequent image degradation. The recently developed refraction corrected multi-focus technique uses subsequent focusing of waves at variable depths, the tracking of travel times of waves reflected from outer and inner cortical bone interfaces, the estimation of the shift needed to focus from one interface to another to determine cortical thickness (Ct.Th), and the speed of sound propagating in a radial bone direction (Ct.ν11). The method was validated previously in silico and ex vivo on plate shaped samples. The aim of this study was to correct phase aberration caused by bone geometry (i.e., curvature and tilt with respect to the transducer array) and intracortical pores for the multi-focus approach. The phase aberration correction methods are based on time delay estimation via bone geometry differences to flat bone plates and via the autocorrelation and cross correlation of the reflected ultrasound waves from the endosteal bone interface. We evaluate the multi-focus approach by incorporating the phase aberration correction methods by numerical simulation and one experiment on a human tibia bone, and analyze the precision and accuracy of measuring Ct.Th and Ct.ν11. Site-matched reference values of the cortical thickness of the human tibia bone were obtained from high-resolution peripheral computed tomography. The phase aberration correction methods resulted in a more precise (coefficient of variation of 5.7%) and accurate (root mean square error of 6.3%) estimation of Ct.Th, and a more precise (9.8%) and accurate (3.4%) Ct.ν11 estimation, than without any phase aberration correction. The developed multi-focus method including phase aberration corrections provides local estimations of both cortical thickness and sound velocity and is proposed as a biomarker of cortical bone quality with high clinical potential for the prevention of osteoporotic fractures. DA - 2022/5// PY - 2022/5// DO - 10.3390/app12105283 VL - 12 IS - 10 SP - SN - 2076-3417 KW - medical beamforming KW - phase aberration correction KW - medical tissue characterization KW - pulse-echo ultrasound KW - medical signal and image processing ER - TY - JOUR TI - Advanced controller synthesis for fuzzy parameter varying systems AU - Ban, Xiaojun AU - Zhang, Hongyang AU - Wu, Fen T2 - JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS AB - A novel nonlinear time-varying model termed as the fuzzy parameter varying (FPV) system is proposed in this research, which inherits both advantages of the conventional T-S fuzzy system in dealing with nonlinear plants and strengths of the linear parameter varying (LPV) system in handling time-varying features. It is, therefore, an attractive mathematical model to efficiently approximate a nonlinear time-varying plant or to serve as a type of time-varying controller. Using the full block S-procedure, sufficient stability conditions have been derived in the form of linear matrix inequalities (LMIs) to test quadratic stability of the open-loop FPV system. Moreover, sufficient conditions have been derived on synthesizing both state feedback and dynamical output feedback fuzzy gain-scheduling controllers that can stabilize the FPV system. An inverted pendulum with a variable length pole is utilized to demonstrate advantages of the FPV system compared to the conventional T-S fuzzy system in representing a practical time-varying nonlinear plant and to validate the controller synthesis conditions. DA - 2022/1// PY - 2022/1// DO - 10.1016/j.jfranklin.2020.12.038 VL - 359 IS - 2 SP - 762-785 SN - 1879-2693 ER - TY - JOUR TI - Effect of Spanwise Hole-to-Hole Spacing on Overall Cooling Effectiveness of Effusion Cooled Combustor Liners for a Swirl-Stabilized Can Combustor AU - Ahmed, Shoaib AU - Wahls, Benjamin H. AU - Ekkad, Srinath V. AU - Lee, Hanjie AU - Ho, Yin-Hsiang T2 - Journal of Turbomachinery AB - Abstract One of the most effective ways to cool the combustor liner is through effusion cooling. Effusion cooling (also known as full-coverage effusion cooling) involves uniformly spaced holes distributed throughout the combustor liner wall. Effusion cooling configurations are preferred for their high effectiveness, low-pressure penalty, and ease of manufacturing. In this article, experimental results are presented for effusion cooling configurations for a realistic swirl driven can combustor under reacting (flame) conditions. The can combustor was equipped with an industrial engine swirler and gaseous fuel (methane), subjecting the liner walls to engine representative flow and combustion conditions. In this study, three different effusion cooling liners with spanwise spacings of r/d = 6, 8, and 10 and streamwise spacing of z/d = 10 were tested for four coolant-to-main airflow ratios. The experiments were carried out at a constant main flow Reynolds number (based on combustor diameter) of 12,500 at a total equivalence ratio of 0.65. Infrared thermography (IRT) was used to measure the liner outer surface temperature, and detailed overall effectiveness values were determined under steady-state conditions. The results indicate that decreasing the spanwise hole-to-hole spacing (r/d) from ten to eight increased the overall cooling effectiveness by 2–5%. It was found that reducing the spanwise hole-to-hole spacing further to r/d = 6 does not affect the cooling effectiveness implying the existence of an optimum spanwise hole-to-hole spacing. Also, the minimum liner cooling effectiveness on the liner wall was found to be downstream of the impingement location, which is not observed in the existing literature for experiments done under nonreacting conditions. DA - 2022/5/27/ PY - 2022/5/27/ DO - 10.1115/1.4054442 VL - 144 IS - 7 SP - LA - en OP - SN - 0889-504X 1528-8900 UR - http://dx.doi.org/10.1115/1.4054442 DB - Crossref KW - heat transfer KW - effusion cooling KW - combustion KW - fluid dynamics and heat transfer phenomena in compressor and turbine components of gas turbine engines KW - heat transfer and film cooling ER - TY - JOUR TI - The Ever-Growing Field of High-Frequency Biomedical Ultrasound AU - Cloutier, Guy AU - Levassort, Franck AU - Jiang, Xiaoning AU - Zhou, Qifa T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - Compared with other medical imaging counterparts, ultrasound has advantages owing to its real-time imaging capability, easy access, and cost-effectiveness. High-frequency (>20 MHz) ultrasound has been developed over the last few decades and is attractive because it provides high-resolution medical imaging and ultrasound backscattering microscopy (UBM) measurements, with applications targeting small animal imaging and some areas of human diagnosis. In recent years, driven by growing needs in intravascular ultrasound (IVUS) imaging, minimally invasive surgery, and particle manipulation, high-frequency ultrasound has continued to flourish as a niche modality and has expanded its important role in both diagnostic imaging and therapy. Concomitant needs have thus arisen in technological research and development to innovate materials, devices, algorithms, and systems for a variety of high-frequency ultrasound applications in medicine and biology. DA - 2022/6// PY - 2022/6// DO - 10.1109/TUFFC.2022.3174370 VL - 69 IS - 6 SP - 1845-1847 SN - 1525-8955 ER - TY - JOUR TI - Ultrasound-Guided Intravascular Sonothrombolysis With a Dual Mode Ultrasound Catheter: In Vitro Study AU - Wu, Huaiyu AU - Zhang, Bohua AU - Huang, Chih-Chung AU - Peng, Chang AU - Zhou, Qifa AU - Jiang, Xiaoning T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - Thromboembolism in vessels often leads to stroke or heart attack and even sudden death unless brought under control. Sonothrombolysis based on ultrasound contrast agents has shown promising outcome in effective treatment of thromboembolism. Intravascular sonothrombolysis transducer was reported recently for unprecedented sonothrombolysis in vitro. However, it is necessary to provide an imaging guide during thrombolysis in clinical applications for optimal treatment efficiency. In this article, a dual mode ultrasound catheter was developed by combining a 16-MHz high-frequency element (imaging transducer) and a 220-kHz low-frequency element (treatment transducer) for sonothrombolysis in vitro. The treatment transducer was designed with a 20-layer PZT-5A stack with the aperture size of 1.2×1.2 mm2, and the imaging transducer with the aperture size of 1.2×1.2 mm2 was attached in front of the treatment transducer. Both transducers were assembled into a customized 2-lm 10-Fr catheter. In vitro experiment was carried out using a bovine blood clot. Imaging tests were conducted, showing that the backscattering signals can be obtained with a high signal-to-noise ratio (SNR) for the 16-MHz imaging transducer. Sonothrombolysis was performed successfully that the volume of clot was reduced significantly after the 30-min treatment. The size changes of clot were observed clearly using the 16-MHz M-mode imaging during the thrombolysis. The findings suggest that the proposed ultrasound-guided intravascular sonothrombolysis can be enhanced since the position of treatment transducer can be adjusted with the target at the clot due to the imaging guide. DA - 2022/6// PY - 2022/6// DO - 10.1109/TUFFC.2022.3153929 VL - 69 IS - 6 SP - 1917-1925 SN - 1525-8955 KW - Imaging-guided sonothombolysis KW - intravascular ultrasound transducer KW - ultrasound imaging ER - TY - JOUR TI - Discrete element method simulator for joint dynamics: a case study using a red-tailed hawk's hallux digit AU - Mollik, Tushar AU - Kennedy, Scott AU - Ul Shougat, Md Raf E. AU - Li, Xiaofu AU - Fitzgerald, Timothy AU - Echols, Scott AU - Kirk, Nick AU - Silverberg, Larry AU - Perkins, Edmon T2 - MULTIBODY SYSTEM DYNAMICS DA - 2022/6/2/ PY - 2022/6/2/ DO - 10.1007/s11044-022-09828-x VL - 6 SP - SN - 1573-272X KW - Discrete element method KW - Dynamic simulation KW - Multibody KW - Biomechanical analysis KW - Skeletal system ER - TY - JOUR TI - An analytical solution simulating growth of Lewy bodies AU - Kuznetsov, Ivan A. AU - Kuznetsov, Andrey V T2 - MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA AB - This paper reports a minimal model simulating the growth of a Lewy body (LB). To the best of our knowledge, this is the first model simulating LB growth. The LB is assumed to consist of a central spherical core, which is composed of membrane fragments and various dysfunctional intracellular organelles, and a halo, which is composed of alpha-synuclein (α-syn) fibrils. Membrane fragments and α-syn monomers are assumed to be produced in the soma at constant rates. The growth of the core and the halo are simulated by the Finke-Watzky model. Analytical (closed-form) solutions describing the growth of the core and the halo are obtained. A sensitivity analysis in terms of model parameters is performed. DA - 2022/6/2/ PY - 2022/6/2/ DO - 10.1093/imammb/dqac006 SP - SN - 1477-8602 KW - alpha-synuclein KW - mathematical modelling KW - Lewy body dementia KW - Parkinson's disease KW - neuron ER - TY - JOUR TI - Principal component analysis based combustion model in the context of a lifted methane/air flame: Sensitivity to the manifold parameters and subgrid closure AU - Malik, Mohammad Rafi AU - Coussement, Axel AU - Echekki, Tarek AU - Parente, Alessandro T2 - COMBUSTION AND FLAME AB - The present work advances the PC-transport approach in the context of Large Eddy Simulation (LES) of turbulent combustion. Accurate modeling of combustion systems requires large kinetic mechanisms. However, realistic high-fidelity simulations of turbulent reacting flows still represent a big challenge on the current computational tools. Therefore, a parameterization of the thermo-chemical state-space using a reduced number of variables is needed. To this end, the potential offered by Principal Component Analysis (PCA) in identifying low-dimensional manifolds is very appealing. The present paper extends the PC-transport approach, coupled with Gaussian Process Regression (GPR), to a lifted methane/air flame in LES. Previous investigations by the authors showed the great potential of the PC-GPR model in the context of Sandia flames. This study investigated some key features of the model: the sensitivity to the training data set and the scaling methods . To this end, two different canonical reactors were used: unsteady counter-flow laminar flames (CFLF) and unsteady perfectly stirred reactor (PSR). Moreover, the authors proposes an approach to address the issue of data density inherent to large numerical data sets, by means of a kernel density weighting of the data set before applying PCA. Finally, a subgrid scale (SGS) closure model was coupled to the PC-transport approach to treat complex turbulence/chemistry interactions. DA - 2022/10// PY - 2022/10// DO - 10.1016/j.combustflame.2022.112134 VL - 244 SP - SN - 1556-2921 UR - https://doi.org/10.1016/j.combustflame.2022.112134 KW - Turbulent combustion KW - Principal component analysis KW - Nonlinear regression KW - Large eddy simulation KW - Auto-ignition KW - Low-dimensional manifolds ER - TY - JOUR TI - Fault Estimation Observer Design for Markovian Jump Systems With Nondifferentiable Actuator and Sensor Failures AU - Chen, Liheng AU - Zhu, Yanzheng AU - Wu, Fen AU - Zhao, Yuxin T2 - IEEE TRANSACTIONS ON CYBERNETICS AB - This article addresses the simultaneous actuator and sensor fault estimation (FE) problem for a class of Markovian jump systems (MJSs) with nondifferentiable actuator failures. In order to overcome the difficulties brought by the nondifferentiable actuator failures, we construct an extended vector composed of states, sensor faults, and disturbances, where the derivatives of actuator failures are not required in this augmented system. Then, two novel observer-based approaches are developed for the augmented descriptor system to cope with the FE problem. The first one is a reduced-order FE observer, where the actuator failures can be estimated by the algebraic input reconstruction strategy. The second one refers to an iterative learning observer (ILO) design method, which can obtain the accurate FE result by integrating the estimations in the iterative processes. The two proposed FE observer design methods can avoid the sliding surface switching problem produced by sliding-mode observers in the area of MJSs. Finally, a practical example of the F-404 aircraft engine system is presented to show the validity of the proposed FE observer design techniques. DA - 2022/5/13/ PY - 2022/5/13/ DO - 10.1109/TCYB.2022.3169290 SP - SN - 2168-2275 KW - Iron KW - Observers KW - Actuators KW - Estimation KW - Switches KW - Markov processes KW - Trajectory KW - Fault detection KW - fault estimation (FE) KW - iterative learning observer (ILO) KW - Markovian jump systems (MJSs) ER - TY - JOUR TI - The evolution of turbulent micro-vortices and their effect on convection heat transfer in porous media AU - Huang, Ching-Wei AU - Srikanth, Vishal AU - Kuznetsov, Andrey V T2 - JOURNAL OF FLUID MECHANICS AB - New insight into the contribution of the microscale vortex evolution to convection heat transfer in porous media is presented in this paper. The objective is to determine how the microscale vortices influence convection heat transfer in turbulent flow inside porous media. The microscale temperature distribution is analysed using flow visualization in two dimensions using streamlines and in three dimensions using the Q -criterion. The pertinent observations are supplemented with a comparison of surface skin friction and heat transfer using: (i) surface skin-friction lines and (ii) the joint probability density function of the pressure and skin-friction coefficients, along with the Nusselt number. The microscale flow phenomena observed are corroborated with the features of the frequency spectra of the drag coefficient and macroscale Nusselt number. The large eddy simulation technique is used in this study to investigate the flow field inside a periodic porous medium. The Reynolds numbers of the flow are 300 and 500. The porous medium consists of solid obstacles in the shape of square and circular cylinders. Two distinct flow regimes are represented by using the porosities of 0.50 and 0.87. The results show that the surface Nusselt number distribution is dependent on whether the micro-vortices are attached to or detached from the surface of the obstacle. The spectra of the macroscale Nusselt number and the pressure drag are similar, signifying a correlation between the dynamics of heat transfer and the microscale turbulent structures. Both vortex shedding and secondary flow instabilities are observed that significantly influence the Nusselt number. The fundamental insight gained in this paper can inform the development of more robust macroscale models of convection heat transfer in turbulent flow in porous media. DA - 2022/5/18/ PY - 2022/5/18/ DO - 10.1017/jfm.2022.291 VL - 942 SP - SN - 1469-7645 KW - vortex instability KW - convection in porous media KW - turbulence simulation ER - TY - JOUR TI - Autonomous Closed-Loop Experimental Characterization and Dynamic Model Validation of a Scaled Underwater Kite AU - Abney, Andrew AU - Reed, James AU - Naik, Kartik AU - Bryant, Samuel AU - Herbert, Dillon AU - Leonard, Zak AU - Vadlamannati, Ashwin AU - Mook, Mariah AU - Beknalkar, Sumedh AU - Alvarez, Miguel AU - Granlund, Kenneth AU - Bryant, Matthew AU - Mazzoleni, Andre AU - Fathy, Hosam AU - Vermillion, Chris T2 - JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME AB - Abstract This paper presents the closed-loop experimental framework and dynamic model validation for a 1/12-scale underwater kite design. The pool-based tow testing framework described herein, which involves a fully actuated, closed-loop controlled kite and flexible tether, significantly expands upon the capabilities of any previously developed open-source framework for experimental underwater kite characterization. Specifically, the framework has allowed for the validation of three closed-loop flight control strategies, along with a critical comparison between dynamic model predictions and experimental results. In this paper, we provide a detailed presentation of the experimental tow system and kite setup, describe the control algorithms implemented and tested, and quantify the level of agreement between our multi-degree-of-freedom kite dynamic model and experimental data. We also present a sensitivity analysis that helps to identify the most influential parameters to kite performance and further explain the remaining mismatches between the model and data. DA - 2022/7/1/ PY - 2022/7/1/ DO - 10.1115/1.4054141 VL - 144 IS - 7 SP - SN - 1528-9028 ER - TY - JOUR TI - Design of a Bio-Inspired Gait Phase Decoder Based on Temporal Convolution Network Architecture With Contralateral Surface Electromyography Toward Hip Prosthesis Control AU - Chen, Yixi AU - Li, Xinwei AU - Su, Hao AU - Zhang, Dingguo AU - Yu, Hongliu T2 - FRONTIERS IN NEUROROBOTICS AB - Inter-leg coordination is of great importance to guarantee the safety of the prostheses wearers, especially for the subjects at high amputation levels. The mainstream of current controllers for lower-limb prostheses is based on the next motion state estimation by the past motion signals at the prosthetic side, which lacks immediate responses and increases falling risks. A bio-inspired gait pattern generation architecture was proposed to provide a possible solution to the bilateral coordination issue. The artificial movement pattern generator (MPG) based on the temporal convolution network, fusing with the motion intention decoded from the surface electromyography (sEMG) measured at the impaired leg and the motion status from the kinematic modality of the prosthetic leg, can predict four sub gait phases. Experiment results suggested that the gait phase decoder exhibited a relatively high intra-subject consistency in the gait phase inference, adapted to various walking speeds with mean decoding accuracy ranging from 89.27 to 91.16% across subjects, and achieved an accuracy of 90.30% in estimating the gait phase of the prosthetic leg in the hip disarticulation amputee at the self-selected pace. With the proof of concept and the offline experiment results, the proposed architecture improves the walking coordination with prostheses for the amputees at hip level amputation. DA - 2022/5/9/ PY - 2022/5/9/ DO - 10.3389/fnbot.2022.791169 VL - 16 SP - SN - 1662-5218 KW - gait phase KW - gait coordination KW - lower limb prosthesis KW - sensor fusion KW - sEMG KW - temporal convolution network KW - detrended cross-correlation analysis (DCCA) KW - hip disarticulation ER - TY - JOUR TI - Demonstration of Coherent Interference between Acoustic Waves Using a Fiber Ring Resonator AU - Kim, Jee Myung AU - Wee, Junghyun AU - Peters, Kara T2 - SENSORS AB - Optical fibers were previously demonstrated to propagate and detect acoustic modes that were converted from Lamb waves for structural health-monitoring applications; typically, a fiber Bragg grating sensor in the optical fiber is used to detect acoustic modes. Acoustic modes can transfer from one fiber to another through a simple adhesive bond coupler, preserving the waveform of the acoustic mode. This paper experimentally investigates the coherence of acoustic waves through the adhesive coupler, using a fiber ring resonator (FRR) configuration. This configuration was chosen because the wave coupled to the second fiber interferes with the original wave after it encircles the fiber ring. We performed this experiment using different geometries of optical fibers in the ring, including a standard single-mode optical fiber, a hollow silica capillary tube, and a large-diameter multi-mode fiber. The results demonstrate that the acoustic wave, when transferring through an adhesive coupler, interferes coherently even when the main and ring fibers are of different types. Finally, we demonstrate that the FRR can be applied for sensing applications by measuring the mode attenuations in the ring due to a changing external environment (water-level sensing) and measuring the optical-path length change in the ring (temperature sensing). DA - 2022/6// PY - 2022/6// DO - 10.3390/s22114163 VL - 22 IS - 11 SP - SN - 1424-8220 UR - https://www.mdpi.com/1424-8220/22/11/4163 KW - structural health monitoring KW - optical fiber KW - acoustic coupling KW - coherent interference KW - fiber ring resonator ER - TY - JOUR TI - Ultrasoft Porous 3D Conductive Dry Electrodes for Electrophysiological Sensing and Myoelectric Control AU - Yao, Shanshan AU - Zhou, Weixin AU - Hinson, Robert AU - Dong, Penghao AU - Wu, Shuang AU - Ives, Jasmine AU - Hu, Xiaogang AU - Huang, He AU - Zhu, Yong T2 - ADVANCED MATERIALS TECHNOLOGIES AB - Abstract Biopotential electrodes have found broad applications in health monitoring, human–machine interactions, and rehabilitation. This article reports the fabrication and applications of ultrasoft breathable dry electrodes that can address several challenges for their long‐term wearable applications—skin compatibility, wearability, and long‐term stability. The proposed electrodes rely on porous and conductive silver nanowire‐based nanocomposites as the robust mechanical and electrical interface. The highly conductive and conformable structure eliminates the necessity of conductive gel while establishing a sufficiently low electrode–skin impedance for high‐fidelity electrophysiological sensing. The introduction of gas‐permeable structures via a simple and scalable method based on sacrificial templates improves breathability and skin compatibility for applications requiring long‐term skin contact. Such conformable and breathable dry electrodes allow for efficient and unobtrusive monitoring of heart, muscle, and brain activities. In addition, based on the muscle activities captured by the electrodes and a musculoskeletal model, electromyogram‐based neural–machine interfaces are realized, illustrating the great potential for prosthesis control, neurorehabilitation, and virtual reality. DA - 2022/5/16/ PY - 2022/5/16/ DO - 10.1002/admt.202101637 SP - SN - 2365-709X KW - biopotential KW - dry electrodes KW - electrocardiogram KW - electroencephalogram KW - electromyogram KW - nanomaterials ER - TY - JOUR TI - Dynamic effects on reservoir computing with a Hopf oscillator AU - Ul Shougat, Md Raf E. AU - Li, XiaoFu AU - Perkins, Edmon T2 - PHYSICAL REVIEW E AB - Limit cycle oscillators have the potential to be resourced as reservoir computers due to their rich dynamics. Here, a Hopf oscillator is used as a physical reservoir computer by discarding the delay line and time-multiplexing procedure. A parametric study is used to uncover computational limits imposed by the dynamics of the oscillator using parity and chaotic time-series prediction benchmark tasks. Resonance, frequency ratios from the Farey sequence, and Arnold tongues were found to strongly affect the computation ability of the reservoir. These results provide insights into fabricating physical reservoir computers from limit cycle systems. DA - 2022/4/25/ PY - 2022/4/25/ DO - 10.1103/PhysRevE.105.044212 VL - 105 IS - 4 SP - SN - 2470-0053 ER - TY - JOUR TI - Leading-edge-vortex tailoring on unsteady airfoils using an inverse aerodynamic approach AU - Suresh Babu, Arun Vishnu AU - Narsipur, Shreyas AU - Bryant, Matthew AU - Gopalarathnam, Ashok T2 - PHYSICS OF FLUIDS AB - In this paper, we present an approach to obtain a desired leading-edge vortex (LEV) shedding pattern from unsteady airfoils through the execution of suitable motion kinematics. Previous research revealed that LEV shedding is associated with the leading-edge suction parameter (LESP) exceeding a maximum threshold. A low-order method called LESP-modulated discrete vortex method (LDVM) was also developed to predict the onset and termination of LEV shedding from an airfoil undergoing prescribed motion kinematics. In the current work, we present an inverse-aerodynamic formulation based on the LDVM to generate the appropriate motion kinematics to achieve a prescribed LESP variation, and thus, the desired LEV shedding characteristics from the airfoil. The algorithm identifies the kinematic state of the airfoil required to attain the target LESP value through an iterative procedure performed inside the LDVM simulation at each time step. Several case studies are presented to demonstrate design scenarios such as tailoring the duration and intensity of LEV shedding, inducing LEV shedding from the chosen surface of the airfoil, promoting or suppressing LEV shedding during an unsteady motion on demand, and achieving similar LEV shedding patterns using different maneuvers. The kinematic profiles generated by the low-order formulation are also simulated using a high-fidelity unsteady Reynolds-averaged Navier–Stokes method to confirm the accuracy of the low-order model. DA - 2022/5// PY - 2022/5// DO - 10.1063/5.0090328 VL - 34 IS - 5 SP - SN - 1089-7666 ER - TY - JOUR TI - Effect of Rotation on Heat Transfer in AR = 2:1 and AR = 4:1 Channels Connected by a Series of Crossover Jets AU - Madhavan, Srivatsan AU - Singh, Prashant AU - Ekkad, Srinath T2 - Journal of Turbomachinery AB - Abstract Detailed heat transfer measurements using transient liquid crystal thermography were performed on a novel cooling design covering the mid-chord and trailing edge region of a typical gas turbine blade under stationary and rotating conditions. The test section comprised two channels with aspect ratio (AR) of 2:1 (mid-chord) and 4:1 (trailing edge), where the coolant was fed into the AR = 2:1 channel from the root. Rib turbulators with a pitch-to-rib height ratio (p/e) of 10 and rib height-to-channel hydraulic diameter ratio (e/Dh) of 0.075 were placed in the AR = 2:1 channel at an angle of 60 deg relative to the direction of flow. The coolant after entering this section was routed to the AR = 4:1 section through a set of crossover jets. The purpose of the crossover jets was to induce sideways impingement onto the pin fins that were placed in the 4:1 section to enhance heat transfer. The 4:1 section had a realistic trapezoidal shape that mimics the trailing edge of an actual gas turbine blade. The pin fins were arranged in a staggered array with a center-to-center spacing of 2.5 times the pin diameter in both spanwise and streamwise directions. The trailing edge section consisted of both radial and cutback exit holes for flow exit. Experiments were performed for the Reynolds number (Redh(AR=2:1)) of 20,000 at Rotation numbers (Rodh(AR=2:1)) of 0, 0.1, and 0.14. The channel-averaged heat transfer coefficient on trailing side was ∼28% (AR = 2:1) and ∼7.6% (AR = 4:1) higher than the leading side for Rotation number (Ro) of 0.1. It is shown that the combination of crossover jets and pin fins can be an effective method for cooling wedge-shaped trailing edge channels over axial cooling flow designs. DA - 2022/2/24/ PY - 2022/2/24/ DO - 10.1115/1.4053237 VL - 144 IS - 6 SP - LA - en OP - SN - 0889-504X 1528-8900 UR - http://dx.doi.org/10.1115/1.4053237 DB - Crossref KW - measurement techniques KW - turbine blade and measurement advancements ER - TY - JOUR TI - Evaluating machine learning classifiers for glaucoma referral decision support in primary care settings AU - Kaskar, Omkar G. AU - Wells-Gray, Elaine AU - Fleischman, David AU - Grace, Landon T2 - SCIENTIFIC REPORTS AB - Several artificial intelligence algorithms have been proposed to help diagnose glaucoma by analyzing the functional and/or structural changes in the eye. These algorithms require carefully curated datasets with access to ocular images. In the current study, we have modeled and evaluated classifiers to predict self-reported glaucoma using a single, easily obtained ocular feature (intraocular pressure (IOP)) and non-ocular features (age, gender, race, body mass index, systolic and diastolic blood pressure, and comorbidities). The classifiers were trained on publicly available data of 3015 subjects without a glaucoma diagnosis at the time of enrollment. 337 subjects subsequently self-reported a glaucoma diagnosis in a span of 1-12 years after enrollment. The classifiers were evaluated on the ability to identify these subjects by only using their features recorded at the time of enrollment. Support vector machine, logistic regression, and adaptive boosting performed similarly on the dataset with F1 scores of 0.31, 0.30, and 0.28, respectively. Logistic regression had the highest sensitivity at 60% with a specificity of 69%. Predictive classifiers using primarily non-ocular features have the potential to be used for identifying suspected glaucoma in non-eye care settings, including primary care. Further research into finding additional features that improve the performance of predictive classifiers is warranted. DA - 2022/5/20/ PY - 2022/5/20/ DO - 10.1038/s41598-022-12270-w VL - 12 IS - 1 SP - SN - 2045-2322 ER - TY - JOUR TI - State of the Art and Future Opportunities in MRI-Guided Robot-Assisted Surgery and Interventions AU - Su, Hao AU - Kwok, Ka-Wai AU - Cleary, Kevin AU - Iordachita, Iulian AU - Cavusoglu, M. Cenk AU - Desai, Jaydev P. AU - Fischer, Gregory S. T2 - PROCEEDINGS OF THE IEEE AB - Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of target anatomy, surrounding tissue, and instrumentation, but there are significant challenges in harnessing it for effectively guiding interventional procedures. Challenges include the strong static magnetic field, rapidly switching magnetic field gradients, high-power radio frequency pulses, sensitivity to electrical noise, and constrained space to operate within the bore of the scanner. MRI has a number of advantages over other medical imaging modalities, including no ionizing radiation, excellent soft-tissue contrast that allows for visualization of tumors and other features that are not readily visible by other modalities, true 3-D imaging capabilities, including the ability to image arbitrary scan plane geometry or perform volumetric imaging, and capability for multimodality sensing, including diffusion, dynamic contrast, blood flow, blood oxygenation, temperature, and tracking of biomarkers. The use of robotic assistants within the MRI bore, alongside the patient during imaging, enables intraoperative MR imaging (iMRI) to guide a surgical intervention in a closed-loop fashion that can include tracking of tissue deformation and target motion, localization of instrumentation, and monitoring of therapy delivery. With the ever-expanding clinical use of MRI, MRI-compatible robotic systems have been heralded as a new approach to assist interventional procedures to allow physicians to treat patients more accurately and effectively. Deploying robotic systems inside the bore synergizes the visual capability of MRI and the manipulation capability of robotic assistance, resulting in a closed-loop surgery architecture. This article details the challenges and history of robotic systems intended to operate in an MRI environment and outlines promising clinical applications and associated state-of-the-art MRI-compatible robotic systems and technology for making this possible. DA - 2022/5/3/ PY - 2022/5/3/ DO - 10.1109/JPROC.2022.3169146 VL - 5 SP - SN - 1558-2256 KW - Magnetic resonance imaging KW - Robots KW - Imaging KW - Robot sensing systems KW - Robot kinematics KW - Biomedical imaging KW - Sensors KW - Fiber optic sensors KW - image-guided surgery KW - magnetic resonance imaging (MRI)-compatible robots KW - piezoelectric actuators KW - sensors and actuators KW - surgical robots ER - TY - JOUR TI - Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities AU - Chi, Yinding AU - Li, Yanbin AU - Zhao, Yao AU - Hong, Yaoye AU - Tang, Yichao AU - Yin, Jie T2 - ADVANCED MATERIALS AB - Snap-through bistability is often observed in nature (e.g., fast snapping to closure of Venus flytrap) and the life (e.g., bottle caps and hair clippers). Recently, harnessing bistability and multistability in different structures and soft materials has attracted growing interest for high-performance soft actuators and soft robots. They have demonstrated broad and unique applications in high-speed locomotion on land and under water, adaptive sensing and fast grasping, shape reconfiguration, electronics-free controls with a single input, and logic computation. Here, an overview of integrating bistable and multistable structures with soft actuating materials for diverse soft actuators and soft/flexible robots is given. The mechanics-guided structural design principles for five categories of basic bistable elements from 1D to 3D (i.e., constrained beams, curved plates, dome shells, compliant mechanisms of linkages with flexible hinges and deformable origami, and balloon structures) are first presented, alongside brief discussions of typical soft actuating materials (i.e., fluidic elastomers and stimuli-responsive materials such as electro-, photo-, thermo-, magnetic-, and hydro-responsive polymers). Following that, integrating these soft materials with each category of bistable elements for soft bistable and multistable actuators and their diverse robotic applications are discussed. To conclude, perspectives on the challenges and opportunities in this emerging field are considered. DA - 2022/5// PY - 2022/5// DO - 10.1002/adma.202110384 VL - 34 IS - 19 SP - SN - 1521-4095 KW - bistability and multistability KW - soft actuating materials KW - soft actuators KW - soft robots KW - structural designs ER - TY - JOUR TI -

The overpoling effect of alternating current poling on rhombohedral Pb(Mg1/3Nb2/3)O-3-PbTiO3 single crystals

AU - Wan, Haotian AU - Luo, Chengtao AU - Kim, Hwang-Pill AU - Chung, Ching-Chang AU - Chang, Wei-Yi AU - Yamashita, Yohachi AU - Jiang, Xiaoning T2 - APPLIED PHYSICS LETTERS AB - The overpoling effect of alternating current poling (ACP) was studied on [001]-orientated rhombohedral Pb(Mg1/3Nb2/3)O3-0.26PbTiO3 (PMN-0.26PT) single crystals. Our experimental results showed that the property enhancement from the ACP was remarkable only when the poling cycle number (NL) was kept low. When ACP was continued after the saturation, dielectric and piezoelectric properties gradually dropped down to traditional direct current poled levels or even lower. Such a decrease in material properties caused by the large NL during ACP was defined as the “overpoling effect of ACP” in this study. The following lattice symmetry and domain structure characterization studies were performed through x-ray diffraction (XRD) and piezoelectric force microscopy (PFM) to find the origin of the overpoling effect. The XRD measurements combined with temperature dependence of dielectric properties demonstrated that the field-induced phase transition continued when the samples became overpoled. Further PFM measurements illustrated that the domain density of the overpoled ACP sample was significantly lower than that of the normal one, while the “2R” domain configuration was maintained through the ACP process. In addition, the hysteresis loop characterization indicated large decreases in the coercive fields. The discovered overpoling effect of ACP could help us understand the mechanisms of ACP and optimize the ACP process. DA - 2022/5/9/ PY - 2022/5/9/ DO - 10.1063/5.0086057 VL - 120 IS - 19 SP - SN - 1077-3118 ER - TY - JOUR TI - Fatigue Damage Diagnostics-Prognostics Framework for Remaining Life Estimation in Adhesive Joints AU - Lyathakula, Karthik Reddy AU - Yuan, Fuh-Gwo T2 - AIAA JOURNAL AB - This work presents an integrated damage diagnostics–prognostics framework for remaining useful life (RUL) estimation in the adhesively bonded joints under fatigue loading. A matching pursuit algorithm is proposed as the diagnostics technique for estimating the damage extent followed by the fatigue damage growth (FDG) simulator as the predictive model for simulating fatigue degradation. The framework calibrates the FDG simulator by quantifying uncertainties in fatigue model parameters using the damage extent data. Bayesian inference via the Markov chain Monte Carlo method is used to quantify uncertainties and estimate the probabilistic RUL from the quantified uncertainties. The FDG simulator encompasses a physics-based fatigue damage degradation model with an artificial neural network-based hybrid machine-learning model for tracing the damage progression. In the diagnostic technique, ultrasonic guided waves are excited into the structure using a pair of piezoelectric wafers, and the damage extent is quantified by reconstructing the reflected signal from the bond region. The proposed diagnostic technique is verified using the ultrasonic signal obtained from the finite element simulations. The damage prognostics part of the integrated framework is verified by estimating RUL in a mixed-mode failure joint specimen using the experimental fatigue damage progression data. In addition, the integrated framework is then verified by estimating RUL in two adhesively bonded joints: a single lap joint and a tapered single lap joint using Gaussian noise added synthetic data and diagnostic damage extent data. DA - 2022/5/10/ PY - 2022/5/10/ DO - 10.2514/1.J060979 VL - 5 SP - SN - 1533-385X UR - http://dx.doi.org/10.2514/1.j060979 ER - TY - JOUR TI - Ca2+ signaling-mediated low-intensity pulsed ultrasound-induced proliferation and activation of motor neuron cells AU - Truong, Thi-Thuyet AU - Chiu, Wen-Tai AU - Lai, Yi-Shyun AU - Huang, Hsien AU - Jiang, Xiaoning AU - Huang, Chih-Chung T2 - ULTRASONICS AB - Motor neuron diseases (MND) including amyotrophic lateral sclerosis and Parkinson disease are commonly neurodegenerative, causing a gradual loss of nerve cells and affecting the mechanisms underlying changes in calcium (Ca2+)-regulated dendritic growth. In this study, the NSC-34 cell line, a population of hybridomas generated using mouse spinal cord cells with neuroblastoma, was used to investigate the effect of low-intensity pulsed ultrasound (LIPUS) as part of an MND treatment model. After NSC-34 cells were seeded for 24 h, LIPUS stimulation was performed on the cells at days 1 and 3 using a non-focused transducer at 1.15 MHz for 8 min. NSC-34 cell proliferation and morphological changes were observed at various LIPUS intensities and different combinations of Ca2+ channel blockers. The nuclear translocation of Ca2+-dependent transcription factors was also examined. We observed that the neurite outgrowth and cell number of NSC-34 significantly increased with LIPUS stimulation at days 2 and 4, which may be associated with the treatment's positive effect on the activation of Ca2+-dependent transcription factors, such as nuclear factor of activated T cells and nuclear factor-kappa B. Our findings suggest that the LIPUS-induced Ca2+ signaling and transcription factor activation facilitate the morphological maturation and proliferation of NSC-34 cells, presenting a promising noninvasive method to improve stimulation therapy for MNDs in the future. DA - 2022/8// PY - 2022/8// DO - 10.1016/j.ultras.2022.106739 VL - 124 SP - SN - 1874-9968 KW - Low-intensity pulsed ultrasound KW - Motor neuron disease KW - NSC-34 cell line KW - Neurite outgrowth KW - Morphology KW - Ca (2+) signaling KW - Ca (2+) -dependent transcription factors ER - TY - JOUR TI - Cooperative Exchange-Based Platooning Using Predicted Fuel-Optimal Operation of Heavy-Duty Vehicles AU - Earnhardt, Christian AU - Groelke, Ben AU - Borek, John AU - Pelletier, Evan AU - Brennan, Sean AU - Vermillion, Chris T2 - IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS AB - Several driving situations exist where fuel-optimal driving in terms of aggregate performance can only be achieved when one or more vehicles incurs a sacrifice in its own fuel consumption. For these situations, an economic incentive is needed to entice that vehicle to participate in aggregate fuel-optimal driving. Focusing on platooning amongst automated heavy-duty vehicles and using real trucking routes, we examine the precise extent to which the benefits of platooning can be expanded through the incorporation of exchange-based incentives. We focus on two mechanisms for incentivized platooning: (i) incentivized “catch-up” along a prescribed highway route and (ii) incentivized re-routing to allow for platooning. For the incentivized “catch-up” mechanism, platoon capable vehicles begin at staggered positions, using a novel platoon catch-up algorithm capable of determining the fuel-optimal platoon engagement position and fuel-optimal velocity trajectories. Additionally, the incentivized re-routing mechanism determines the optimal route for a network of platoon-capable vehicles, allowing for a vehicle to reroute its trajectory to engage within the platoon. Because such scenarios will be shown to frequently lead to aggregate benefit, while actually hurting the fuel economy of one or more participants, we propose three methods for explicitly computing the monetary value of the exchange. Assuming a known trajectory and traffic pattern, the first uses the Shapley value to determine the exchange value. The second method adjusts the Shapley value, accounting for uncertainty associated with traffic modeling. The final method assumes a competitive market, requiring each individual operator to implement a bid. DA - 2022/5/2/ PY - 2022/5/2/ DO - 10.1109/TITS.2022.3169390 SP - SN - 1558-0016 KW - Fuels KW - Aggregates KW - Aerodynamics KW - Biological system modeling KW - Drag KW - Routing KW - Roads KW - Optimization KW - velocity control KW - cooperative systems KW - automotive control KW - navigation ER - TY - JOUR TI - Novel Surface Flow-Reversal Sensor Applied to Detection of Airfoil Stall AU - Aleman, Maria A. AU - Gopalarathnam, Ashok AU - Granlund, Kenneth T2 - JOURNAL OF AIRCRAFT AB - No AccessEngineering NotesNovel Surface Flow-Reversal Sensor Applied to Detection of Airfoil StallMaria A. Aleman, Ashok Gopalarathnam and Kenneth GranlundMaria A. Aleman https://orcid.org/0000-0001-5538-0299North Carolina State University, Raleigh, North Carolina 27695*Ph.D. Candidate, Department of Mechanical and Aerospace Engineering; . Student Member AIAA.Search for more papers by this author, Ashok Gopalarathnam https://orcid.org/0000-0002-1119-7887North Carolina State University, Raleigh, North Carolina 27695†Professor, Department of Mechanical and Aerospace Engineering; . Associate Fellow AIAA.Search for more papers by this author and Kenneth Granlund https://orcid.org/0000-0002-0108-8038North Carolina State University, Raleigh, North Carolina 27695‡Assistant Professor, Department of Mechanical and Aerospace Engineering; . Associate Fellow AIAA.Search for more papers by this authorPublished Online:15 May 2022https://doi.org/10.2514/1.C036732SectionsRead Now ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail About References [1] Komerath N. M., Liou S. G., Schwartz R. J. and Kim J. M., “Flow over a Twin-Tailed Aircraft at Angle of Atack, Part I: Spatial Characteristics,” Journal of Aircraft, Vol. 29, No. 3, 1992, pp. 413–420. https://doi.org/10.2514/3.46177 LinkGoogle Scholar[2] Karpovich E., Gueraiche D., Sergeeva N. and Kuznetsov A., “Investigation of a Light Boxplane Model Using Tuft Flow Visualization and CFD,” Fluids, Vol. 6, No. 12, 2021, https://www.mdpi.com/2311-5521/6/12/451 [retrieved 20 Jan. 2022]. https://doi.org/10.3390/fluids6120451 CrossrefGoogle Scholar[3] Dhawan S., “Direct Measurements of Skin Friction,” NASA Rept. 1121, 1953. Google Scholar[4] Brown K. C. and Joubert P. 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Google Scholar Previous article Next article FiguresReferencesRelatedDetails What's Popular Volume 59, Number 5September 2022 CrossmarkInformationCopyright © 2022 by Maria A. Aleman, Ashok Gopalarathnam, and Kenneth Granlund. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. All requests for copying and permission to reprint should be submitted to CCC at www.copyright.com; employ the eISSN 1533-3868 to initiate your request. See also AIAA Rights and Permissions www.aiaa.org/randp. TopicsAerodynamic PerformanceAerodynamicsAeronautical EngineeringAeronauticsAviationAviation SafetyAvionicsFlight TestGuidance, Navigation, and Control SystemsPressure SensorsSensorsSkin FrictionTransducersTurbulenceWind Tunnels KeywordsFlow SensorsAirfoilWind Tunnel TestsLift CoefficientBoundary Layer SeparationAdverse Pressure GradientAerodynamic CharacteristicsTwo Dimensional FlowShear StressStatic PressurePDF Received28 October 2021Accepted4 April 2022Published online15 May 2022 DA - 2022/5/13/ PY - 2022/5/13/ DO - 10.2514/1.C036732 VL - 5 SP - SN - 1533-3868 UR - https://doi.org/10.2514/1.C036732 ER - TY - JOUR TI - Age-Dependent Upper Limb Myoelectric Control Capability in Typically Developing Children AU - Gonzalez, Miguel AU - Su, Hao AU - Fu, Qiushi T2 - IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING AB - Research in EMG-based control of prostheses has mainly utilized adult subjects who have fully developed neuromuscular control. Little is known about children's ability to generate consistent EMG signals necessary to control artificial limbs with multiple degrees of freedom. As a first step to address this gap, experiments were designed to validate and benchmark two experimental protocols that quantify the ability to coordinate forearm muscle contractions in typically developing children. Non-disabled, healthy adults and children participated in our experiments that aimed to measure an individual's ability to use myoelectric control interfaces. In the first experiment, participants performed 8 repetitions of 16 different hand/wrist movements. Using offline classification analysis based on Support Vector Machine, we quantified their ability to consistently produce distinguishable muscle contraction patterns. We demonstrated that children had a smaller number of highly independent movements (can be classified with >90% accuracy) than adults did. The second experiment measured participants' ability to control the position of a cursor on a 1-DoF virtual slide using proportional EMG control with three different visuomotor gain levels. We found that children had higher failure rates and slower average target acquisitions than adults did, primarily due to longer correction times that did not improve over repetitive practice. We also found that the performance in both experiments was age-dependent in children. The results of this study provide novel insights into the technical and empirical basis to better understand neuromuscular development in children with upper-limb loss. DA - 2022/// PY - 2022/// DO - 10.1109/TNSRE.2022.3166800 VL - 30 SP - 1009-1018 SN - 1558-0210 KW - Electromyography KW - Task analysis KW - Pediatrics KW - Electrodes KW - Protocols KW - Particle measurements KW - Neuromuscular KW - Myoelectric control KW - pattern recognition KW - motor development KW - upper limb KW - children ER - TY - JOUR TI - Soft electrothermal actuators using silver nanowire heaters (vol 9, pg 3797, 2017) AU - Yao, Shanshan AU - Cui, Jianxun AU - Cui, Zheng AU - Zhu, Yong T2 - NANOSCALE AB - Correction for 'Soft electrothermal actuators using silver nanowire heaters' by Shanshan Yao et al., Nanoscale, 2017, 9, 3797-3805, https://doi.org/10.1039/C6NR09270E. DA - 2022/5/5/ PY - 2022/5/5/ DO - 10.1039/d2nr90086f VL - 14 IS - 17 SP - 6671-6671 SN - 2040-3372 ER - TY - JOUR TI - Scaling effects in the alternating-current poling of thin PIN-PMN-PT single crystals AU - Kim, Hwang-Pill AU - Wan, Haotian AU - Lu, Xuanming AU - Yamashita, Yohachi AU - Jiang, Xiaoning T2 - APPLIED PHYSICS LETTERS AB - AC-poling of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals with a thickness of 0.06–0.16 mm was studied in this paper. Compared with DC-poled samples, enhancements in piezoelectric and dielectric properties can be obtained when the thickness is above 0.1 mm. However, inconsistency in poling effects was found in the crystals with thickness below 0.1 mm. To elucidate why such scaling effect arises, surface roughness was measured by an atomic force microscopy to correlate surface morphology and poling effects. It was found that non-uniform surface roughness led to inconsistent and decreased properties. Furthermore, temperature-dependent dielectric permittivity spectra were measured to explore how crystal thickness affects the thermal stability of ferroelectric phases. It is noted that complex changes in crystallographic symmetries emanate by decreasing thickness. Such phenomena can be attributed to more influential effects of surface morphology when thickness is reduced. We hope this work suggests a clue for solving the scaling effects of AC-poling on relaxor-PbTiO3 single crystals. DA - 2022/4/4/ PY - 2022/4/4/ DO - 10.1063/5.0084994 VL - 120 IS - 14 SP - SN - 1077-3118 ER - TY - JOUR TI - Flexible-Time Receding Horizon Iterative Learning Control With Application to Marine Hydrokinetic Energy Systems AU - Cobb, Mitchell AU - Reed, James AU - Wu, Maxwell AU - Mishra, Kirti D. AU - Barton, Kira AU - Vermillion, Chris T2 - IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY AB - This brief presents an iterative learning control (ILC) framework for a class of repetitive control (RC) applications characterized by: 1) continuous operation; 2) flexible iteration time; and 3) an economic performance metric. Specifically, the effect of iteration-varying initial conditions, resulting from the continuous nature of the operation, is accounted for through an iteration domain receding horizon formulation. To address the need for flexible iteration times, the time-domain dynamics are transformed into path-domain dynamics characterized by a non-dimensional parameter spanning an iteration-invariant range. The resulting model is used to derive learning filters that minimize a multi-objective economic cost. The proposed methodology is applied to the control a kite-based marine hydrokinetic (MHK) system, which executes high-speed, repetitive flight paths with the objective of maximizing its lap-averaged power output. The proposed approach is validated via simulations of a medium-fidelity nonlinear model of a kite-based MHK system, and the results demonstrate robust and fast convergence of the kite to power-optimal flight patterns. DA - 2022/4/22/ PY - 2022/4/22/ DO - 10.1109/TCST.2022.3165734 SP - SN - 1558-0865 KW - Economics KW - Time-domain analysis KW - Iterative learning control KW - Predictive models KW - Indexes KW - Trajectory KW - Optimization KW - Iterative learning control (ILC) KW - marine energy systems KW - optimal path following KW - receding horizon control KW - renewable energy systems KW - repetitive control (RC) ER - TY - JOUR TI - A Study on Thermal Properties of Composite Metal Foams for Applications in Tank Cars Carrying Hazardous Materials AU - Rabiei, Afsaneh AU - Amoafo-Yeboah, Nigel AU - Huseboe, Evan AU - Scemama, Claire T2 - METAL-MATRIX COMPOSITES: ADVANCES IN PROCESSING, CHARACTERIZATION, PERFORMANCE AND ANALYSIS AB - Each year, millions of tons of hazardous materials are shipped through tank cars on railroads. Accidents involving these tank cars can create punctures that release these hazardous materials into the surrounding area, resulting in potential fire and even explosions, human fatalities, and substantial damage to the environment. Despite all enhancements to mitigate the consequences of such accidents, there is still an immediate need for novel material with superior puncture and fire resistance with lower weight than the current carbon-steel in use, to improve the safety and efficacy of tank cars carrying hazardous materials (HAZMAT). Composite metal foamComposite metal foam (CMF) is a novel class of light-weight material made of closely packed metallic hollow spheres with a surrounding metallic matrix. In this study, the latest developments on evaluating the performance of composite metal foamComposite metal foam against extreme heat through both experimental and analytical approaches will be reported and compared to those properties of the base bulk steel materials in use. DA - 2022/// PY - 2022/// DO - 10.1007/978-3-030-92567-3_23 SP - 367-379 SN - 2367-1696 KW - Composite metal foam KW - Thermal conductivity KW - Specific heat capacity KW - Coefficient of thermal expansion KW - Thermal diffusivity ER - TY - JOUR TI - Understanding the role of bond point strain in the mechanical response of nonwoven polypropylene materials AU - Garmabi, Alireza AU - Elamin, Mohamed A. AU - Bradford, Philip D. AU - Pankow, Mark T2 - JOURNAL OF COMPOSITE MATERIALS AB - A method was developed to study micromechanics of a bond point in nonwoven polypropylene materials. The micromechanical behavior of the thermal bonded nonwovens was studied using the digital image correlation (DIC) technique to understand the bond points deformation during mechanical stretching. An electrospray technique was used as a fast and reliable method to create the speckle pattern on the nonwovens. Various parameters of the electrospraying and their influence on the pattern accuracy and repeatability was studied and the best pattern in terms of dot size and distribution was determined from experimentation. Plasma treatment also proved to be essential to enhance the uniform distribution and adherence of the particles on the surface. Unloaded DIC experiments were carried out and proved the accuracy of technique with errors of lower than 0.5% strain. An automated high-resolution tensile apparatus was built and loaded DIC experiments were carried out using the device. The fabric was tested in Machine Direction (MD) direction and Cross Direction (CD) directions, both showing good correlation with low errors. Average strain values in bond points were plotted against total strain in fabric and the results showed noticeable amounts of strains developed in the bond points, contradictory to most of the FEM models which consider no deformation in the bond points. Results also indicated that in MD direction deformation, bond points can experience more than 30% of the overall strain presented in the fabric. DA - 2022/4/6/ PY - 2022/4/6/ DO - 10.1177/00219983221087332 SP - SN - 1530-793X KW - nonwovens KW - mechanical testing KW - micromechanics KW - digital image correlation ER - TY - JOUR TI - Physics-based Computational Method Predicting the Dielectric Properties of Polymer Nanocomposites AU - Islam, Md Didarul AU - Liu, Sipan AU - Choi, Daniel AU - Guo, Zhanhu AU - Ryu, Jong Eun T2 - APPLIED COMPOSITE MATERIALS DA - 2022/4/9/ PY - 2022/4/9/ DO - 10.1007/s10443-022-10026-3 VL - 29 IS - 4 SP - SN - 1573-4897 UR - https://doi.org/10.1007/s10443-022-10026-3 KW - Dielectric properties KW - Effective permittivity KW - Nanocomposites KW - Energy storage KW - Finite element analysis (FEA) ER - TY - JOUR TI - Implications of Spatially Constrained Bipennate Topology on Fluidic Artificial Muscle Bundle Actuation AU - Duan, Emily AU - Bryant, Matthew T2 - ACTUATORS AB - In this paper, we investigate the design of pennate topology fluidic artificial muscle bundles under spatial constraints. Soft fluidic actuators are of great interest to roboticists and engineers, due to their potential for inherent compliance and safe human–robot interaction. McKibben fluidic artificial muscles are an especially attractive type of soft fluidic actuator, due to their high force-to-weight ratio, inherent flexibility, inexpensive construction, and muscle-like force-contraction behavior. The examination of natural muscles has shown that those with pennate fiber topology can achieve higher output force per geometric cross-sectional area. Yet, this is not universally true for fluidic artificial muscle bundles, because the contraction and rotation behavior of individual actuator units (fibers) are both key factors contributing to situations where bipennate muscle topologies are advantageous, as compared to parallel muscle topologies. This paper analytically explores the implications of pennation angle on pennate fluidic artificial muscle bundle performance with spatial bounds. A method for muscle bundle parameterization as a function of desired bundle spatial envelope dimensions has been developed. An analysis of actuation performance metrics for bipennate and parallel topologies shows that bipennate artificial muscle bundles can be designed to amplify the muscle contraction, output force, stiffness, or work output capacity, as compared to a parallel bundle with the same envelope dimensions. In addition to quantifying the performance trade space associated with different pennate topologies, analyzing bundles with different fiber boundary conditions reveals how bipennate fluidic artificial muscle bundles can be designed for extensile motion and negative stiffness behaviors. This study, therefore, enables tailoring the muscle bundle parameters for custom compliant actuation applications. DA - 2022/3// PY - 2022/3// DO - 10.3390/act11030082 VL - 11 IS - 3 SP - SN - 2076-0825 KW - biomimetic KW - pennate topology KW - soft actuators KW - fluidic artificial muscles KW - muscle topology ER - TY - JOUR TI - Nondestructive examination of polymer composites by analysis of polymer-water interactions and damage-dependent hysteresis AU - Idolor, Ogheneovo AU - Berkowitz, Katherine AU - Guha, Rishabh Debraj AU - Grace, Landon T2 - COMPOSITE STRUCTURES AB - Polymer composites are currently replacing metals in applications requiring design flexibility, high strength-to-weight ratio, and corrosion resistance. However, the damage modes in these materials are very different from metals and require specialized techniques to detect internal flaws which may exist even in the absence of visible surface damage. This study proposes a technique for damage detection in polymer composites which uses naturally absorbed moisture as an ‘imaging’ agent. The locally higher concentration of water in the ‘free’ state at damaged regions and the tendency of such water to quickly migrate to and from damage sites—exhibiting damage-dependent hysteresis—is leveraged for damage detection. To identify damaged regions, a machine learning approach is adopted using logistic regression to classify local regions as ‘undamaged’ or ‘damaged’. New possibilities resulting from higher sensitivity levels achievable by damage-dependent hysteresis are highlighted, providing a pathway to field deployment of the novel damage detection technique. DA - 2022/5/1/ PY - 2022/5/1/ DO - 10.1016/j.compstruct.2022.115377 VL - 287 SP - SN - 1879-1085 KW - Nondestructive examination KW - Polymer matrix composites KW - Moisture diffusion KW - Dielectric properties KW - Machine learning KW - Hysteresis ER - TY - JOUR TI - Wall-Modeled Large Eddy Simulation of High Speed Flows AU - Mettu, Balachandra R. AU - Subbareddy, Pramod K. T2 - AIAA JOURNAL AB - The use of wall-modeled large-eddy simulation (WMLES) is explored in the context of compressible flows with a focus on cold-wall boundary layers and flows with shock-induced separation. It is observed that for cold-wall flows, a “mixed” scaling for the length scale appearing in the eddy viscosity formulation outperforms the classical semilocal scaling for obtaining predictions of heat flux and skin friction. A few shock/boundary-layer interaction (SBLI) cases are examined in some detail, and model modifications are proposed to overcome identified deficiencies. It is shown that using WMLES the low-frequency characteristics of SBLI at high Reynolds number can be quantitatively captured. A dynamically switched version of the equilibrium model is proposed; this shows promise for relatively inexpensive simulations at these conditions. DA - 2022/3/16/ PY - 2022/3/16/ DO - 10.2514/1.J061501 SP - SN - 1533-385X ER - TY - JOUR TI - Effect of Pin Fins on Jet Impingement Heat Transfer Over a Rotating Disk AU - Bhansali, Pratik S. AU - Ramakrishnan, Kishore Ranganath AU - Ekkad, Srinath V. T2 - Journal of Heat Transfer AB - Abstract Many engineering applications consist of rotating components that experience high-heat load. Applications like the gas turbine engine consist of rotating disks and the study of heat transfer over such rotating surfaces is of particular interest. In the case of gas turbines, the disk also needs to be protected from the ingress of hot turbine gases caused by the low-pressure region created due to the radially outward pumping of fluid close to the rotating surface. The present experimental study investigates the effects of introducing pin-fins on heat transfer over surface of a rotating gas-turbine disk. The experiments were conducted at rotational Reynolds numbers (ReR) of 5487–12,803 based on the disk diameter (D) and jet Reynolds numbers (Re) of 5000–18,000 based on the jet diameter. The effects of nozzle to target spacing (z/d=2−6), eccentricity of impingement (ε = 0−0.67), angle of impingement—both toward and away from the center (θi and θo=0 deg−20 deg), and the pin fin height (Hf=3.05 mm−19.05 mm) were studied. Steady-state temperature measurements were taken using thermocouples embedded in the disk close to the target surface, and area average Nusselt number (Nu) was calculated. The results have been compared with those for a smooth aluminum disk of equal dimensions and without any pin-fins. The average Nu was significantly enhanced by the presence of pin-fins. The enhancement was higher for lower values of Re, and the maximum enhancement was found to be 3.9 times that of a smooth disk for Re=5000. In the impingement dominant regime, the effect of disk rotation was minimal for a smooth disk, but the heat transfer increased with rotational speed in case of pin-fins. There was no impact of eccentricity on Nu for ε = 0 and 0.33. For ε = 0.67, the maximum reduction in enhancement over a smooth surface (21.95%) was observed when compared with coaxial impingement for stationary impingement for Re=18,000 and z/d=4. The effect of inclination angle was insignificant, and no clear trend could be established. Higher heat transfer rates were observed for z/d=6 with the increasing Re, and this effect diminished with the increase in the rotational speed. With the increase in pin-fin height, especially at higher values of Re, there was in increase in the value of Nu. Qualitative visualization of flow field has been performed for smooth and the pin-fin case using the commercial simulation package Ansys Fluent to further understand the flow features that result in the heat transfer enhancement. DA - 2022/2/10/ PY - 2022/2/10/ DO - 10.1115/1.4053371 VL - 144 IS - 4 SP - LA - en OP - SN - 0022-1481 1528-8943 UR - http://dx.doi.org/10.1115/1.4053371 DB - Crossref KW - jet impingement KW - turbine disk KW - rotating disk KW - pin-fins ER - TY - JOUR TI - Organic solar powered greenhouse performance optimization and global economic opportunity AU - Ravishankar, Eshwar AU - Booth, Ronald E. AU - Hollingsworth, Joseph A. AU - Ade, Harald AU - Sederoff, Heike AU - DeCarolis, Joseph F. AU - Brendan T. O'Connor, T2 - ENERGY & ENVIRONMENTAL SCIENCE AB - This work integrates greenhouse energy demand, solar power production, and plant growth modeling to assess the economic opportunity of organic solar powered greenhouses. Results show these systems have positive economic outlook across broad climates. DA - 2022/3/10/ PY - 2022/3/10/ DO - 10.1039/d1ee03474j SP - SN - 1754-5706 ER - TY - JOUR TI - Electron beam sintering (EBS) process for Ultra-High Temperature Ceramics (UHTCs) and the comparison with traditional UHTC sintering and metal Electron Beam Melting (EBM) processes AU - Pasagada, Venkata Keerti Vardhan AU - Yang, Ni AU - Xu, Chengying T2 - CERAMICS INTERNATIONAL AB - Ultra-high temperature ceramics (UHTCs) are refractory materials with unusual properties making them strong contenders for applications involving adverse and chemically aggressive environments. This paper presents an effort to process UHTCs using an additive manufacturing method, specifically Electron Beam Sintering (EBS) - adoption of the Electron Beam powder-bed fusion (PBF) process. Such a process shows that the processing and consolidation phenomenon of UHTCs are different from what is observed in the traditional sintering process of UHTCs and Electron Beam Melting (EBM) of typical metals or alloys. In this article, the EBS process of UHTCs is studied. The differences between EBS and the two aforementioned traditional processing methods are analyzed. The scientific hypotheses have been backed by experimental results on a ZrB2 – 30 vol% ZrSi2 UHTC mixture using an electron beam via Liquid Phase Sintering (LPS) theory. Efforts to develop processing conditions to fabricate dense and defect-free UHTC components are explored with the help of finite element (FE) simulations. Characterization of the EBS processed samples using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) revealed unique needle-like patterned grains of ZrB2 in a ZrSi2 matrix. Our findings demonstrate the feasibility of the EBS process to produce dense layers of UHTCs for coatings, potential three-dimensional, as well as complex-shaped applications. DA - 2022/4/1/ PY - 2022/4/1/ DO - 10.1016/j.ceramint.2021.12.229 VL - 48 IS - 7 SP - 10174-10186 SN - 1873-3956 KW - Electron beam sintering KW - Electron beam melting KW - Ultra-high temperature ceramics KW - Additive manufacturing KW - Liquid phase sintering ER - TY - JOUR TI - Novel 3-D Spacer Textiles to Protect Crops from Insect Infestation and That Enhance Plant Growth AU - Cave, Grayson L. AU - West, Andre J. AU - McCord, Marian G. AU - Koene, Bryan AU - Beck, J. Benjamin AU - Deguenon, Jean M. AU - Luan, Kun AU - Roe, R. Michael T2 - AGRICULTURE-BASEL AB - Pesticide-free, 3-D, spacer fabrics (Plant Armor Generation (PA Gen) 1 and 2) were investigated for proof-of-concept as an insect barrier to protect plants and improve plant agronomics for organic farming. The time to 50% penetration (TP50) for tobacco thrips, Frankliniella fusca (Hinds) adults in laboratory Petri dish bioassays was 30 and 175 min for PA Gen 1 and 2, respectively, and 12 min for the control (a commercially available, single layer-crop cover, Proteknet). PA Gen 2 was ≥90% resistant to penetration of unfed caterpillar neonates, Helicoverpa zea (Boddie), while the TP50‘s for Gen 1 and Proteknet were 3.1 and 2.35 h, respectively. In small cage studies, PA Gen 2 covered potted cabbage plants were 100% resistant to penetration by these insects through 10 d after which the study was ended. In small field plot studies for 3 summer months, cabbage plants grew approximately twice as fast when covered versus not covered with Gen 1 and Gen 2 without the need for insecticides or herbicides. This was not observed for the control crop cover. Martindale abrasion tests demonstrated Gen 1 and 2 were at least 6- and 1.8-fold more durable than the control crop cover used. Data are also presented on percentage light, water, air, and water vapor penetration across each textile and operational temperatures and humidity for cabbage plants covered and uncovered in small field plots. DA - 2022/4// PY - 2022/4// DO - 10.3390/agriculture12040498 VL - 12 IS - 4 SP - SN - 2077-0472 UR - https://doi.org/10.3390/agriculture12040498 KW - insect control KW - organic farming KW - non-insecticidal KW - spacer fabric KW - enhanced plant growth ER - TY - JOUR TI - Mixture fraction measurement in turbulent non-premixed MILD jet flame using Rayleigh scattering AU - Sahoo, Abinash AU - Ramachandran, Aravind AU - Narayanaswamy, Venkateswaran AU - Lyons, Kevin M. T2 - Applied Optics AB - Turbulent combustion of jet flames in a hot diluted coflow of combustion products is conducive to the transition from conventional flamelet combustion to a regime of moderate or intense low oxygen dilution (MILD) combustion, which is commonly characterized by a very low emission and noise. MILD combustion is also characterized by distributed combustion where the net heat release is positive across the entire combustion domain. The turbulence/chemistry interactions in this regime that determine the flame structure, local temperature, and species distribution critically depend on the mixture fraction and scalar dissipation fields. However, there are no experimental tools to measure the mixture fraction field in a distributed (MILD) combustion regime. The present work offsets this limitation by demonstrating a Rayleigh scattering-based approach to measure mixture fraction in a turbulent ethylene MILD combustion zone. 1D counterflow flame simulations enabled mapping the locally calibrated Rayleigh scattering fields to mixture fractions in the fuel-rich regions. This approach also shows very low sensitivity to the local temperature and composition. Overall, the results provide compelling evidence that the distributed heat release does not significantly impact the turbulent processes of the flow-field for the conditions examined. The measurement uncertainty from this approach and its extension to more complex fuels are also discussed. The present technique is limited to mildly turbulent, fully MILD/distributed flame with representative scalar dissipation rates. DA - 2022/// PY - 2022/// DO - 10.1364/AO.444109 VL - 61 IS - 9 SP - 2338-2351 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85127193360&partnerID=MN8TOARS ER - TY - JOUR TI - Generalized Empirical Regret Bounds for Control of Renewable Energy Systems in Spatiotemporally Varying Environments AU - Haydon, Ben AU - Cole, Jack AU - Dunn, Laurel AU - Keyantuo, Patrick AU - Chow, Fotini K. AU - Moura, Scott AU - Vermillion, Chris T2 - JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME AB - Abstract This paper focuses on the empirical derivation of regret bounds for mobile systems that can optimize their locations in real-time within a spatiotemporally varying renewable energy resource. The case studies in this paper focus specifically on an airborne wind energy system, where the replacement of towers with tethers and a lifting body allows the system to adjust its altitude continuously, with the goal of operating at the altitude that maximizes net power production. While prior publications have proposed control strategies for this problem, often with favorable results based on simulations that use real wind data, they lack any theoretical or statistical performance guarantees. In this work, we make use of a very large synthetic dataset, identified through parameters from real wind data, to derive probabilistic bounds on the difference between optimal and actual performance, termed regret. The results are presented for a variety of control strategies, including maximum probability of improvement, upper confidence bound, greedy, and constant altitude approaches. In addition, we use dimensional analysis to generalize the aforementioned results to other spatiotemporally varying environments, making the results applicable to a wider variety of renewably powered mobile systems. Finally, to deal with more general environmental mean models, we introduce a novel approach to modify calculable regret bounds to accommodate any mean model through what we term an “effective spatial domain.” DA - 2022/4/1/ PY - 2022/4/1/ DO - 10.1115/1.4052396 VL - 144 IS - 4 SP - SN - 1528-9028 ER - TY - JOUR TI - Store Separation Trajectory Clusters from Machine Learning AU - Gothard, William D. AU - Granlund, Kenneth O. T2 - JOURNAL OF AIRCRAFT AB - Store separation of a generic, thin-finned, missile through a continuously oscillating shear layer into subsonic flow was conducted experimentally through 100 drop tests to identify potential groups of trajectories and statistical phenomena. Change in store pitch was observed using a high-speed camera. Trajectories were grouped using machine learning with a -means clustering, followed by a Gaussian mixture model clustering approach. The -means clustering revealed two primary groups and one outlier group. The statistical strength of the primary groups was confirmed with the Gaussian mixture model, which places 89% of trajectories into one of two groups. The existence of two primary groups is strong evidence of a bifurcation. DA - 2022/// PY - 2022/// DO - 10.2514/1.C036261 VL - 59 IS - 1 SP - 117-125 SN - 1533-3868 KW - Gaussian Mixture Models KW - Shear Layers KW - Flow Conditions KW - Aerodynamic Properties KW - Karman Vortex Street KW - Wind Tunnel Walls KW - Cluster Analysis KW - Fluid Structure Interaction KW - Probability Distribution KW - Dynamic Time Warping ER - TY - JOUR TI - Deep thrombosis characterization using photoacoustic imaging with intravascular light delivery AU - Tang, Yuqi AU - Wu, Huaiyu AU - Klippel, Paul AU - Zhang, Bohua AU - Huang, Hsiao-Ying Shadow AU - Jing, Yun AU - Jiang, Xiaoning AU - Yao, Junjie T2 - BIOMEDICAL ENGINEERING LETTERS AB - Venous thromboembolism (VTE) is a condition in which blood clots form within the deep veins of the leg or pelvis to cause deep vein thrombosis. The optimal treatment of VTE is determined by thrombus properties such as the age, size, and chemical composition of the blood clots. The thrombus properties can be readily evaluated by using photoacoustic computed tomography (PACT), a hybrid imaging modality that combines the rich contrast of optical imaging and deep penetration of ultrasound imaging. With inherent sensitivity to endogenous chromophores such as hemoglobin, multispectral PACT can provide composition information and oxygenation level in the clots. However, conventional PACT of clots relies on external light illumination, which provides limited penetration depth due to strong optical scattering of intervening tissue. In our study, this depth limitation is overcome by using intravascular light delivery with a thin optical fiber. To demonstrate in vitro blood clot characterization, clots with different acuteness and oxygenation levels were placed underneath ten-centimeter-thick chicken breast tissue and imaged using multiple wavelengths. Acoustic frequency analysis was performed on the received PA channel signals, and oxygenation level was estimated using multispectral linear spectral unmixing. The results show that, with intravascular light delivery, clot oxygenation level can be accurately measured, and the clot age can thus be estimated. In addition, we found that retracted and unretracted clots had different acoustic frequency spectrum. While unretracted clots had stronger high frequency components, retracted clots had much higher low frequency components due to densely packed red blood cells. The PACT characterization of the clots was consistent with the histology results and mechanical tests. DA - 2022/2/16/ PY - 2022/2/16/ DO - 10.1007/s13534-022-00216-0 SP - SN - 2093-985X KW - Thrombosis KW - Photoacoustic tomography KW - Internal light illumination KW - Photoacoustic frequency KW - Retracted blood clot KW - Unretracted blood clot KW - Blood oxygenation ER - TY - JOUR TI - A new technique using background oriented schlieren for temperature reconstruction of an axisymmetric open reactive flow AU - Wahls, Benjamin H. AU - Ekkad, Srinath V T2 - MEASUREMENT SCIENCE AND TECHNOLOGY AB - Abstract A new technique, called 3D ray tracing, for refractive index field reconstruction of axisymmetric flows from displacement fields measured from background oriented schlieren (BOS) experiments is developed and applied to a lean premixed methane/air reactive flow at Reynolds number of 4000 on a 12 mm diameter circular burner. The temperature distribution is then calculated using a species independent direct relationship between refractive index, temperature, and ambient conditions. The error introduced by the approximation to reach this relationship is quantified using simulated flow fields and is found to be 8% within the inner unburnt region of the flow field, decreasing to 2% through the reaction zone, and then quickly reducing to 0% outside the flow field. The effect of random noise and reconstruction resolution on the accuracy of the method is assessed via application to synthetically generated data sets that mimic the characteristics of a heated air jet expelled into ambient. The novel 3D ray tracing allows for accurate temperature reconstructions of open axisymmetric reactive flows where 2D displacement fields are measured, which is shown to be a shortcoming of current direct methods in literature. Additionally, this is done without the need for any prior knowledge of flow field parameters; only ambient conditions to the system must be known. The simple experimental setup and low computational cost make this approach with BOS a good option for application into existing experimental combustion systems with minimal effort. DA - 2022/5/1/ PY - 2022/5/1/ DO - 10.1088/1361-6501/ac51a5 VL - 33 IS - 5 SP - SN - 1361-6501 KW - background oriented schlieren KW - noninvasive KW - temperature KW - measurement KW - reactive flow ER - TY - JOUR TI - An effective PBPK model predicting dissolved drug transfer from a representative nasal cavity to the blood stream AU - Dave, Sujal AU - Kleinstreuer, Clement AU - Chari, Sriram T2 - JOURNAL OF AEROSOL SCIENCE AB - Predicting the fate of nasally administered drugs is important for the understanding and possible improvement of in vivo performance. When computational fluid-particle dynamics (CFPD) results are coupled with a physiologically based pharmacokinetic (PBPK) model, drug concentrations in the blood stream can be obtained. Specifically, hybrid CFPD-PBPK simulations can predict inhaled particle transport, deposition, and uptake in the nasal mucus layers and subsequently absorbed drug migration from the nasal cavity to the blood stream.The computer simulation results of Chari et al. (2021) were used as input to a basic PBPK model to track the deposited and dissolved drugs from the nasal cavities to the blood stream. Employing the open-source toolbox OpenFOAM, our PBPK model predictions were compared with experimental in vivo data sets for different corticosteroids. The relative differences between experimental and simulated values of PK metrics, following administration of mometasone furoate nasal spray, were all 7% or less. Drug plasma concentrations based on different drug parameters, such as solubility and partition coefficient, were studied as well. The drug concentration in the plasma was found to increase with an increase in drug solubility (Cs = 0.02 mg/ml, 0.1 mg/ml, 0.2 mg/ml). The same trend was observed for different partition coefficients (Kow = 5e-3, 2, 5000), where the plasma concentration curve peaked for a partition coefficient of 5000. It was also observed that drug dosage controls the amount of residual drug concentrations in the plasma with the passage of time. Two different drug dosages were studied, ie, 50 μg and 800 μg, with the former being completely absorbed in the plasma after 8 h; however, in the latter case the drug was not completely absorbed after that time interval. These modeling and simulation results are useful for planning aspects in drug development, as the predictions provide physical insight to differences in device, formulation, and dosage selection. DA - 2022/2// PY - 2022/2// DO - 10.1016/j.jaerosci.2021.105898 VL - 160 SP - SN - 1879-1964 KW - Intranasal drugs KW - Hybrid CFPD-PBPK model KW - Disposition of inhaled drugs KW - Pharmacokinetic modeling KW - Drug concentrations in the blood stream ER - TY - JOUR TI - Predictive Model of Dynamic Mechanical Properties of VE Damper Based on Acrylic Rubber-Graphene Oxide Composites Considering Aging Damage AU - Ge, Teng AU - Xu, Zhao-Dong AU - Yuan, Fuh-Gwo T2 - JOURNAL OF AEROSPACE ENGINEERING AB - Because shock absorbers are an important component of high-rise buildings, it is essential to be able to detect damage to them. Viscoelastic (VE) dampers, as a common shock absorber, directly affect the safety and reliability of VE materials over the entire life of structures. This study is aimed at optimizing a high-dissipation VE material with excellent aging resistance. The VE damper was developed after aging of anti-aging and high-dissipation VE materials. To analyze the damping and mechanical properties of the VE dampers in detail, mechanical performance testing was conducted on VE dampers under various loading conditions, demonstrating that dampers had excellent mechanical properties and confirming the anti-aging properties of the VE materials. In addition, a fractional standard linear solid model based on damage modification is proposed, and aging is considered in the mathematical model of VE dampers as an indispensable factor. After the simulated value is compared to the experimental results, it is found that the fractional mathematical model that involves the aging factor precisely describes the real-time mechanical properties of the VE damper. DA - 2022/3/1/ PY - 2022/3/1/ DO - 10.1061/(ASCE)AS.1943-5525.0001385 VL - 35 IS - 2 SP - SN - 1943-5525 KW - Viscoelastic (VE) damper KW - Aging resistance KW - Mechanical performance tests KW - Damage evolution KW - Predictive model ER - TY - JOUR TI - Utilization of Secondary Jet in Cavitation Peening and Cavitation Abrasive Jet Polishing AU - Pang, Hao AU - Ngaile, Gracious T2 - MICROMACHINES AB - The cavitation peening (CP) and cavitation abrasive jet polishing (CAJP) processes employ a cavitating jet to harden the surface or remove surface irregularities. However, a zero incidence angle between the jet and the surface limits the efficiency of these two processes. This limitation can be improved by introducing a secondary jet. The secondary jet interacts with the main jet, carrying bubbles to the proximity of the workpiece surface and aligning the disordered bubble collapse events. Through characterizing the treated surface of AL6061 in terms of the hardness distribution and surface roughness, it was found out that the secondary jet can increase the hardening intensity by 10%, whereas the material removal rate within a localized region increased by 66%. In addition, employing multiple secondary jets can create a patched pattern of hardness distribution. Another finding is that the hardening effect of the cavitation increases with the processing time at first and is then saturated. DA - 2022/1// PY - 2022/1// DO - 10.3390/mi13010086 VL - 13 IS - 1 SP - SN - 2072-666X KW - cavitation KW - peening KW - jet polishing ER - TY - JOUR TI - Electromagnetic Finite-Element Modeling of Induction Effects for Buried Objects in Magnetic Soils AU - Elbadry, Mohamed H. AU - Wetherington, Josh AU - Zikry, Mohammed A. T2 - IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING AB - A frequency-based finite element (FE) framework has been developed to predict and understand the response of an electromagnetic induction (EMI) sensor due to buried targets. The EMI sensor is used to detect buried targets in magnetic nonconducting soils. The framework was verified with an analytical model that utilizes dipole approximations. The framework was then used to predict the electromagnetic (EM) response due to interrelated stimuli and properties. The results indicate that the sensor was not sensitive to small variations (0–200 mm) in the standoff height and lateral positions, and only showed a significant change in the response due to stand-off variations that were greater than 200 mm. This low sensitivity to minor variations in standoff height and lateral position signify that there are critical distances related to the EM response of buried objects. The response to different target conductivities and permeabilities was also investigated for steel and aluminum targets. The lower conductivity steel targets had EM responses, where the inductive limit was reached at higher frequencies than the higher conductivity aluminum targets. Variations in target permeabilities for steel showed that as permeabilities increased, the frequencies at which the inductive limit was reached also increased. This verified predictive approach can provide a methodology to characterize the EM response of buried objects for a broad class of buried object EM properties, geometries, and input stimuli. DA - 2022/// PY - 2022/// DO - 10.1109/TGRS.2021.3124839 VL - 60 SP - SN - 1558-0644 UR - https://doi.org/10.1109/TGRS.2021.3124839 KW - Electromagnetic induction (EMI) KW - finite element method (FEM) KW - magnetic susceptibility KW - soil ER - TY - JOUR TI - An Analysis of Sonothrombolysis and Cavitation for Retracted and Unretracted Clots Using Microbubbles Versus Low-Boiling-Point Nanodroplets AU - Kim, Jinwook AU - Bautista, Kathlyne Jayne B. AU - Deruiter, Ryan M. AU - Goel, Leela AU - Jiang, Xiaoning AU - Xu, Zhen AU - Dayton, Paul A. T2 - IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL AB - The thrombolysis potential of low-boiling-point (-2 °C) perfluorocarbon phase-change nanodroplets (NDs) has previously been demonstrated on aged clots, and we hypothesized that this efficacy would extend to retracted clots. We tested this hypothesis by comparing sonothrombolysis of both unretracted and retracted clots using ND-mediated ultrasound (US+ND) and microbubble-mediated ultrasound (US+MB), respectively. Assessment data included clot mass reduction, cavitation detection, and cavitation cloud imaging in vitro. Acoustic parameters included a 7.9-MPa peak negative pressure and 180-cycle bursts with 5-Hz repetition (the corresponding duty cycle and time-averaged intensity of 0.09% and 1.87 W/cm2, respectively) based on prior studies. With these parameters, we observed a significantly reduced efficacy of US+MB in the retracted versus unretracted model (the averaged mass reduction rate from 1.83%/min to 0.54%/min). Unlike US+MB, US+ND exhibited less reduction of efficacy in the retracted model (from 2.15%/min to 1.04%/min on average). The cavitation detection results correlate with the sonothrombolysis efficacy results showing that both stable and inertial cavitation generated in a retracted clot by US+ND is higher than that by US+MB. We observed that ND-mediated cavitation shows a tendency to occur inside a clot, whereas MB-mediated cavitation occurs near the surface of a retracted clot, and this difference is more significant with retracted clots compared to unretracted clots. We conclude that ND-mediated sonothrombolysis outperforms MB-mediated therapy regardless of clot retraction, and this advantage of ND-mediated cavitation is emphasized for retracted clots. The primary mechanisms are hypothesized to be sustained cavitation level and cavitation clouds in the proximity of a retracted clot by US+ND. DA - 2022/2// PY - 2022/2// DO - 10.1109/TUFFC.2021.3137125 VL - 69 IS - 2 SP - 711-719 SN - 1525-8955 KW - Ultrasonic imaging KW - Acoustics KW - Medical treatment KW - Frequency control KW - Coagulation KW - Transducers KW - Surface treatment KW - Cavitation KW - microbubble (MB) KW - nanodroplet (ND) KW - retracted clot KW - sonothrombolysis KW - thrombosis ER - TY - JOUR TI - Recent progress on AC poling of relaxor-PbTiO3 ferroelectric single crystals: a review AU - Sun, Yiqin AU - Karaki, Tomoaki AU - Yamashita, Yohachi T2 - JAPANESE JOURNAL OF APPLIED PHYSICS AB - Abstract Compared to conventional DC poling (DCP) treatment, in 2014 a novel technology, AC poling (ACP) treatment, was found to be a low-cost, time-saving and smart-process method to significantly enhance the properties of relaxor-PbTiO 3 (PT) ferroelectric single crystal (SC) transducers. In total, over 35 papers have been reported since 2018 in which researchers achieved a piezoelectric coefficient of ( d 33 ) > 4000 pC/N and electromechanical coupling factors of ( k 33 ) > 96% for the ACP SCs. In this review, we introduce the history of ACP study on relaxor-PT SCs, and our research group’s ACP study during the past three years. In particular, we focus on ACP conditions and their mechanisms of binary (1- x )Pb(Mg 1/3 Nb 2/3 )O 3 - x PbTiO 3 (PMN-PT) and ternary (1- x - y )Pb(In 1/2 Nb 1/2 )O 3 - y Pb(Mg 1/3 Nb 2/3 )O 3 - x PbTiO 3 (PIN-PMN-PT) SCs near the morphotropic phase boundary (MPB). Furthermore, we provide insight for further studies on optimal ACP conditions and the reduction of spurious-mode vibrations (SMVs). This work offers promising prospects and practical value for high-end ultrasonic imaging probe transducers. DA - 2022/2/1/ PY - 2022/2/1/ DO - 10.35848/1347-4065/ac3a90 VL - 61 IS - SB SP - SN - 1347-4065 KW - AC poling KW - ferroelectric KW - single crystal KW - ultrasonic transducer KW - spurious-mode vibration ER - TY - JOUR TI - Motor unit buckling in variable recruitment fluidic artificial muscle bundles: implications and mitigations AU - Mazzoleni, Nicholas AU - Kim, Jeong Yong AU - Bryant, Matthew T2 - SMART MATERIALS AND STRUCTURES AB - Abstract Fluidic artificial muscles (FAMs) are a popular actuation choice due to their compliant nature and high force-to-weight ratio. Variable recruitment is a bio-inspired actuation strategy in which multiple FAMs are combined into motor units that can be pressurized sequentially according to load demand. In a traditional ‘fixed-end’ variable recruitment FAM bundle, inactive units and activated units that are past free strain will compress and buckle outward, resulting in resistive forces that reduce overall bundle force output, increase spatial envelope, and reduce operational life. This paper investigates the use of inextensible tendons as a mitigation strategy for preventing resistive forces and outward buckling of inactive and submaximally activated motor units in a variable recruitment FAM bundle. A traditional analytical fixed-end variable recruitment FAM bundle model is modified to account for tendons, and the force–strain spaces of the two configurations are compared while keeping the overall bundle length constant. Actuation efficiency for the two configurations is compared for two different cases: one case in which the radii of all FAMs within the bundle are equivalent, and one case in which the bundles are sized to consume the same amount of working fluid volume at maximum contraction. Efficiency benefits can be found for either configuration for different locations within their shared force–strain space, so depending on the loading requirements, one configuration may be more efficient than the other. Additionally, a study is performed to quantify the increase in spatial envelope caused by the outward buckling of inactive or low-pressure motor units. It was found that at full activation of recruitment states 1, 2, and 3, the tendoned configuration has a significantly higher volumetric energy density than the fixed-end configuration, indicating that the tendoned configuration has more actuation potential for a given spatial envelope. Overall, the results show that using a resistive force mitigation strategy such as tendons can completely eliminate resistive forces, increase volumetric energy density, and increase system efficiency for certain loading cases. Thus, there is a compelling case to be made for the use of tendoned FAMs in variable recruitment bundles. DA - 2022/3/1/ PY - 2022/3/1/ DO - 10.1088/1361-665X/ac49d9 VL - 31 IS - 3 SP - SN - 1361-665X KW - bioinspiration KW - fluidic artificial muslces KW - variable recruitment KW - McKibben actuators KW - motor unit buckling ER - TY - JOUR TI - Evoked Tactile Feedback and Control Scheme on Functional Utility of Prosthetic Hand AU - Vargas, Luis AU - Huang, He AU - Zhu, Yong AU - Hu, Xiaogang T2 - IEEE ROBOTICS AND AUTOMATION LETTERS AB - Fine manual control relies on intricate action-perception coupling to effectively interact with objects . Here, we evaluated how electrically evoked artificial tactile sensation can be integrated into the functional utility of a prosthetic hand. Using different myoelectric-control strategies, participants performed a modified box-and-block task using a prosthetic hand. Transcutaneous nerve stimulation was employed to elicit somatotopic fingertip tactile feedback reflecting prosthetic fingertip forces. This feedback was evoked using an electrode grid placed along the participants’ upper arm targeting the median and ulnar nerve bundles. Myoelectric signals from the finger flexor and extensor controlled the prosthetic joint velocity or position. Participants lifted, held, and transported cubes of varying weights using their minimum grip forces. The results showed that participants exerted lower forces and presented lower number of failed trials (prematurely dropped objects) when feedback was provided with respect to without feedback. We also found that position control required more flexor muscle activation compared with velocity control when tactile feedback was provided. Our findings reveal that non-invasively evoked tactile feedback could be used to effectively enable human-in-the-loop control of a prosthetic hand. The outcomes can provide a platform to characterize the action-perception couplings during prosthetic control, in order to improve user experience and system functionality. DA - 2022/4// PY - 2022/4// DO - 10.1109/LRA.2021.3139147 VL - 7 IS - 2 SP - 1300-1307 SN - 2377-3766 KW - Tactile sensation KW - transcutaneous nerve stimulation KW - prosthetic hand KW - functional task KW - haptic feedback ER - TY - JOUR TI - AI reflections in 2021 AU - Buckner, Cameron AU - Miikkulainen, Risto AU - Forrest, Stephanie AU - Milano, Silvia AU - Zou, James AU - Prunk, Carina AU - Irrgang, Christopher AU - Cohen, I. Glenn AU - Su, Hao AU - Murphy, Robin R. AU - Taylor, Russell H. AU - Krieger, Axel AU - Kovac, Mirco AU - Sadowski, Jathan AU - Marda, Vidushi T2 - NATURE MACHINE INTELLIGENCE AB - For a third year in a row, we followed up with authors of several recent Comments and Perspectives in Nature Machine Intelligence about what happened after their article was published: how did the topic they wrote about develop, did they gain new insights, and what are their hopes and expectations for AI in 2022? DA - 2022/1/25/ PY - 2022/1/25/ DO - 10.1038/s42256-021-00435-7 VL - 1 SP - SN - 2522-5839 ER - TY - JOUR TI - Analysis of improved oral drug delivery with different helical stream inhalation modes AU - Gurumurthy, Adithya AU - Kleinstreuer, Clement T2 - COMPUTERS IN BIOLOGY AND MEDICINE AB - A challenging aspect of pulmonary drug delivery devices, e.g., metered dose inhalers (MDIs), is to deliver therapeutic drugs to prescribed target locations at the required dosage level. In this study, validated computer simulations of micron-drug inhalation with angled or radially positioned helical fluid-particle streams are simulated and analyzed. For a suitable swirl number significant improvements in drug delivery, especially to deeper lung regions, have been achieved. Specifically, considering realistic polydisperse particle distributions at the mouth inlet for a subject-specific upper lung airway geometry, a 10-degree angled helical stream increased the local efficacy by up to 26% in comparison to a conventional helical stream, causing an overall dosage of about 60% to the deep lung. Considering lobe-specific drug targeting scenarios, while using an off-center, i.e., radially well positioned, helical-flow mouthpiece, the local particle-deposition efficacy increased from 9% to 24% in the left lobe and from 25% to 38% in the right lobe in comparison to conventional drug-aerosol stream released from the central position. The efficacy of helical streams for pulmonary drug delivery applications has been established. DA - 2022/2// PY - 2022/2// DO - 10.1016/j.compbiomed.2021.105132 VL - 141 SP - SN - 1879-0534 KW - Pulmonary drug delivery KW - Polydisperse particle distribution KW - Subject-specific upper lung airway geometry KW - Helical drug-aerosol streams KW - Swirl number KW - Angled helical injection KW - Radially positioned helical injection KW - Lobe-specific drug targeting ER - TY - JOUR TI - Boundary curvature guided programmable shape-morphing kirigami sheets AU - Hong, Yaoye AU - Chi, Yinding AU - Wu, Shuang AU - Li, Yanbin AU - Zhu, Yong AU - Yin, Jie T2 - NATURE COMMUNICATIONS AB - Abstract Kirigami, a traditional paper cutting art, offers a promising strategy for 2D-to-3D shape morphing through cut-guided deformation. Existing kirigami designs for target 3D curved shapes rely on intricate cut patterns in thin sheets, making the inverse design challenging. Motivated by the Gauss-Bonnet theorem that correlates the geodesic curvature along the boundary with the Gaussian curvature, here, we exploit programming the curvature of cut boundaries rather than the complex cut patterns in kirigami sheets for target 3D curved morphologies through both forward and inverse designs. The strategy largely simplifies the inverse design. Leveraging this strategy, we demonstrate its potential applications as a universal and nondestructive gripper for delicate objects, including live fish, raw egg yolk, and a human hair, as well as dynamically conformable heaters for human knees. This study opens a new avenue to encode boundary curvatures for shape-programing materials with potential applications in soft robotics and wearable devices. DA - 2022/1/26/ PY - 2022/1/26/ DO - 10.1038/s41467-022-28187-x VL - 13 IS - 1 SP - SN - 2041-1723 ER - TY - JOUR TI - Design, analysis, and validation of an orderly recruitment valve for bio-inspired fluidic artificial muscles AU - Vemula, Dheeraj AU - Kim, Jeong Yong AU - Mazzoleni, Nicholas AU - Bryant, Matthew T2 - BIOINSPIRATION & BIOMIMETICS AB - Biological musculature employs variable recruitment of muscle fibers from smaller to larger units as the load increases. This orderly recruitment strategy has certain physiological advantages like minimizing fatigue and providing finer motor control. Recently fluidic artificial muscles (FAM) are gaining popularity as actuators due to their increased efficiency by employing bio-inspired recruitment strategies such as active variable recruitment (AVR). AVR systems use a multi-valve system (MVS) configuration to selectively recruit individual FAMs depending on the load. However, when using an MVS configuration, an increase in the number of motor units in a bundle corresponds to an increase in the number of valves in the system. This introduces greater complexity and weight. The objective of this paper is to propose, analyze, and demonstrate an orderly recruitment valve (ORV) concept that enables orderly recruitment of multiple FAMs in the system using a single valve. A mathematical model of an ORV-controlled FAM bundle is presented and validated by experiments performed on a proof-of-concept ORV experiment. The modeling is extended to explore a case study of a 1-DOF robot arm system consisting of an electrohydraulic pressurization system, ORV, and a FAM-actuated rotating arm plant and its dynamics are simulated to further demonstrate the capabilities of an ORV-controlled closed-loop system. An orderly recruitment strategy was implemented through a model-based feed forward controller. To benchmark the performance of the ORV, a conventional MVS with equivalent dynamics and controller was also implemented. Trajectory tracking simulations on both the systems revealed lower tracking error for the ORV controlled system compared to the MVS controlled system due to the unique cross-flow effects present in the ORV. However, the MVS, due to its independent and multiple valve setup, proved to be more adaptable for performance. For example, modifications to the recruitment thresholds of the MVS demonstrated improvement in tracking error, albeit with a sacrifice in efficiency. In the ORV, tracking performance remained insensitive to any variation in recruitment threshold. The results show that compared to the MVS, the ORV offers a simpler and more compact valving architecture at the expense of moderate losses in control flexibility and performance. DA - 2022/3/1/ PY - 2022/3/1/ DO - 10.1088/1748-3190/ac4381 VL - 17 IS - 2 SP - SN - 1748-3190 KW - fluidic artificial muscle KW - variable recruitment KW - McKibben actuator ER - TY - JOUR TI - Design of a scalable, flexible, and durable thermoelectric cooling device for soft electronics using Kirigami cut patterns AU - Rosenberg, Z. B. AU - Weiner, N. C. AU - Shahariar, H. AU - Li, B. M. AU - Peavey, J. L. AU - Mills, A. C. AU - Losego, M. D. AU - Jur, J. S. T2 - FLEXIBLE AND PRINTED ELECTRONICS AB - Abstract A flexible, soft thermoelectric cooling device is presented that shows potential for human cooling applications in wearable technologies and close-to-body applications. Current developments lack integration feasibility due to non-scalable assembly procedures and unsuitable materials for comfortable and durable integration into products. Our devices have been created and tested around the need to conform to the human body which we have quantified through the creation of a repeatable drape testing procedure, a metric used in the textile industry. Inspired by mass manufacturing constraints, our flexible thermoelectric devices are created using commercially available materials and scalable processing techniques. Thermoelectric legs are embedded in a foam substrate to provide flexibility, while Kirigami-inspired cuts are patterned on the foam to provide the drape necessary for mimicking the performance of textile and close to body materials. In total, nine different configurations, three different fill factors and three different Kirigami cut patterns were fabricated and inspected for thermal characterization, mechanical testing, flexibility and drape. Our studies show that adding Kirigami patterns can increase the durability of the device, improve the flexibility, decrease the drape coefficient, and have <1% of impact on cooling performance at higher fill factors (>1.5%), reaching temperature differences up to 4.39 °C ± 0.17 °C between the hot and cold faces of the device. These thermoelectric cooling devices show great flexibility, durability, and cooling for integration into soft cooling products. DA - 2022/3/1/ PY - 2022/3/1/ DO - 10.1088/2058-8585/ac48a0 VL - 7 IS - 1 SP - SN - 2058-8585 KW - e-textiles KW - flexible thermoelectrics KW - thermoelectric cooling devices KW - flexible electronics KW - wearable electronics ER - TY - JOUR TI - Multilayer microfluidic platform for the study of luminal, transmural, and interstitial flow AU - Lee, Gi-hun AU - Huang, Stephanie A. AU - Aw, Wen Y. AU - Rathod, Mitesh L. AU - Cho, Crescentia AU - Ligler, Frances S. AU - Polacheck, William J. T2 - BIOFABRICATION AB - Efficient delivery of oxygen and nutrients to tissues requires an intricate balance of blood, lymphatic, and interstitial fluid pressures (IFPs), and gradients in fluid pressure drive the flow of blood, lymph, and interstitial fluid through tissues. While specific fluid mechanical stimuli, such as wall shear stress, have been shown to modulate cellular signaling pathways along with gene and protein expression patterns, an understanding of the key signals imparted by flowing fluid and how these signals are integrated across multiple cells and cell types in native tissues is incomplete due to limitations with current assays. Here, we introduce a multi-layer microfluidic platform (MμLTI-Flow) that enables the culture of engineered blood and lymphatic microvessels and independent control of blood, lymphatic, and IFPs. Using optical microscopy methods to measure fluid velocity for applied input pressures, we demonstrate varying rates of interstitial fluid flow as a function of blood, lymphatic, and interstitial pressure, consistent with computational fluid dynamics (CFD) models. The resulting microfluidic and computational platforms will provide for analysis of key fluid mechanical parameters and cellular mechanisms that contribute to diseases in which fluid imbalances play a role in progression, including lymphedema and solid cancer. DA - 2022/4/1/ PY - 2022/4/1/ DO - 10.1088/1758-5090/ac48e5 VL - 14 IS - 2 SP - SN - 1758-5090 KW - microfluidics KW - vascular biology KW - interstitial flow KW - hemodynamics KW - biofluid mechanics KW - mechanotransduction ER - TY - JOUR TI - Spurious-mode vibrations caused by alternating current poling and their solution process for Pb(Mg1/3Nb2/3)O-3-PbTiO3 single crystals AU - Sun, Yiqin AU - Karaki, Tomoaki AU - Fujii, Tadashi AU - Yamashita, Yohachi John T2 - JOURNAL OF MATERIOMICS AB - The effects of alternating current poling (ACP) at 80 °C on electrical properties of [001]-oriented 0.72 Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-28PT) single crystals (SCs) have been investigated. The square-wave ACP SCs poled at high voltage (HV, 5 kVrms/cm) occasionally showed large fluctuations and low opposite values of piezoelectric coefficient (d33 = ± 1370 pC/N) in one plate. This revealed spurious-mode vibrations (SMV) of impedance spectrum. However, after depolarizing and repolarizing the sample with a sine-wave ACP at low voltage (LV, 3.5 kVrms/cm), the d33 enhanced to be 1720 pC/N (+26%) and did not exhibit large fluctuation or opposite values in one plate any more. The impedance spectrum became clean and the abnormal SMV disappeared. We proposed four possible mechanisms of the SMV, and speculate that the main cause maybe by macro-scale sub-domain structure and/or phase change in the main domain structure and/or phase in the SC plate due to the specific poling conditions not eternal mechanical damage of PMN-PT SCs. This study will be useful to realize a high d33 and improve other properties of PMN-PT ACP SC ultrasonic transducers without any SMV for high-frequency medical imaging equipment. DA - 2022/1// PY - 2022/1// DO - 10.1016/j.jmat.2021.05.002 VL - 8 IS - 1 SP - 96-103 SN - 2352-8478 KW - Alternating current poling KW - Ferroelectric single crystal KW - Ultrasonic transducer KW - Spurious mode vibration KW - Piezoelectric property ER - TY - JOUR TI - Overall Cooling Effectiveness of Effusion Cooled Can Combustor Liner Under Reacting and Non-Reacting Conditions AU - Ahmed, Shoaib AU - Ramakrishnan, Kishore Ranganath AU - Ekkad, Srinath V T2 - JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS AB - Abstract Emphasis on lean premixed combustion in modern low NOX combustion chambers limits the air available for cooling the combustion liner. Hence, the development of optimized liner cooling designs is imperative for effective usage of available coolant. An effective way to cool a gas turbine combustor liner is through effusion cooling. Effusion cooling (also known as full-coverage film cooling) involves uniformly spaced holes distributed throughout the liner’s curved surface area. This study presents findings from an experimental study on the characterization of the overall cooling effectiveness of an effusion-cooled liner wall, which was representative of a can combustor under heated flow (non-reacting) and lean-combustion (reacting) conditions. The model can combustor was equipped with an industrial swirler, which subjected the liner walls to engine representative flow and combustion conditions. In this study, two different effusion cooling liners with an inline and staggered arrangement of effusion holes have been studied. Non-dimensionalized streamwise hole-to-hole spacing (z/d) and spanwise hole-to-hole spacing (r/d) of 10 were used for both the effusion liners. These configurations were tested for five different blowing ratios ranging from 0.7 to 4.0 under both reacting and non-reacting conditions. The experiments were carried out at a constant main flow Reynolds number (based on combustor diameter) of 12,500. The non-reacting experiments were carried out by heating the mainstream air, and the reacting experiments were carried out under flame conditions at a total equivalence ratio of 0.65. Infrared thermography (IRT) was used to measure the liner outer surface temperature, and detailed overall effectiveness values were determined under steady-state conditions. It was observed that overall cooling effectiveness trends were different under reacting and non-reacting conditions. The cooling effectiveness for the non-reacting experiments exhibited a decreasing trend, and no consistent location of minimum cooling effectiveness was observed for the range of blowing ratios investigated in this study. For the reacting cases, the cooling effectiveness first follows a decreasing trend, reaches a distinct minimum, and then increases till the end of the combustor. Under non-reacting conditions, the staggered configuration was 9–25% more effective than inline configuration, and under reacting conditions, the staggered configuration was 4–8% more effective than inline configuration. From this study, it is clear that the coolant flame interaction for the reacting experiments impacted the liner cooling effectiveness and led to different overall cooling effectiveness distribution on the liner when compared with the non-reacting experiments. DA - 2022/2/1/ PY - 2022/2/1/ DO - 10.1115/1.4051371 VL - 14 IS - 2 SP - SN - 1948-5093 KW - heat transfer KW - effusion cooling KW - combustion KW - combustion and reactive flows KW - experimental KW - measurement techniques KW - gas turbine heat transfer ER - TY - JOUR TI - Characterization of Transient Wall Heat Load for a Low NOx Lean Premixed Swirl Stabilized Can Combustor Under Reacting Conditions AU - Ramakrishnan, Kishore Ranganath AU - Ahmed, Shoaib AU - Ekkad, Srinath V T2 - JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS AB - Abstract As stringent emissions controls are being placed on gas turbines, modern combustor design optimization is contingent on the accurate characterization of the combustor flame side heat loads. Power generation turbines are increasingly moving toward natural gas, biogas, and syngas, whose composition is highly dependent on the sourcing location. With fuel flexible nozzles, it is important to understand the heat load from various gas mixtures to optimize the cooling design to make sure the liner is not under/over cooled for some mixtures as this has a larger effect on NOx/CO emissions. In addition to knowing the heat load distribution, it is important to understand the peak heat load under start/stop transient conditions which tend to be much higher than steady-state/cruise altitude heat loads. The present work focuses on the experimental measurement of the transient heat load along a can combustor under reacting conditions for a swirl-stabilized premixed methane–air flame. Tests were carried out under various equivalence ratios, Reynolds numbers, and pilot fuel flowrate. An infrared camera was used to measure the inner and outer wall temperatures of the liner to calculate the liner heat load. Particle image velocimetry (PIV) was employed to visualize the flowfield for various reacting conditions studied in this work. Based on the heat transfer study, a detailed report of transient heat load along the length of the liner wall has been presented here. Initial start transient heat load on the liner wall is ∼10–40% more than the steady-state heat load. DA - 2022/2/1/ PY - 2022/2/1/ DO - 10.1115/1.4051375 VL - 14 IS - 2 SP - SN - 1948-5093 KW - gas turbine KW - combustion KW - heat transfer KW - low NOx KW - swirl stabilized KW - premixed KW - combustion and reactive flows KW - experimental KW - measurement techniques KW - very high-temperature heat transfer ER - TY - JOUR TI - A study on the creep behavior of alloy 709 using in-situ scanning electron microscopy AU - Lall, Amrita AU - Bowen, Paul AU - Rabiei, Afsaneh T2 - MATERIALS CHARACTERIZATION AB - In this research, an experimental evaluation of creep properties of Alloy 709 in the temperature range of 750–850 °C was undertaken. Alloy 709 is a novel austenitic stainless steel with 20% Cr and 25% Ni by wt% that was developed for application in structural components of nuclear power plants. Creep rupture tests were conducted in an in-situ heating-loading and Scanning Electron Microscope (SEM) unit equipped with Electron Backscatter Diffraction (EBSD) detector and Energy Dispersive Spectroscopy (EDS). “Real-time” creep damage mechanisms of Alloy 709 at various stresses and temperatures using a flat, un-notched sample with continuously reducing cross-section is studied so that the failure and maximum creep damage occurred at the center of the sample where the in-situ SEM imaging could be focused. Accelerated creep tests at temperatures and stresses above service conditions were performed by employing multiple blocks of constant loads where the loads were increased once the sample attained constant creep rate, indicating a secondary creep regime. This technique ensures multiple data points can be obtained from the same test, saves the time required for an otherwise long-term creep test and usage of SEM. Coincident Site Lattice (CSL) boundary maps were collected as control maps before testing, and the grain boundaries were observed during the creep test to understand the effect of grain boundary character on the creep damage mechanism. Void growth, grain boundary separation, and sliding were found to be the main creep mechanisms whose rate is dependent on stress and temperature. Failure mechanisms studied on the fracture surface using SEM fractography were correlated to the sample surface observations to create complementary information to better understand the underline creep mechanism of Alloy 709. DA - 2022/1// PY - 2022/1// DO - 10.1016/j.matchar.2021.111587 VL - 183 SP - SN - 1873-4189 KW - In-situ scanning electron microscope KW - Creep KW - Alloy 709 KW - Austenitic stainless steel ER - TY - JOUR TI - A numerical and experimental approach to compare the effect of sample thickness in small in-situ SEM and large ex-situ tensile testing in Alloy 709 AU - Lall, Amrita AU - Bowen, Paul AU - Rabiei, Afsaneh T2 - MATERIALS CHARACTERIZATION AB - ASTM standards for tensile tests define specific sample size requirements regardless of grain size of the material. However, sample size requirements for testing should be considered in conjunction with the number of grains within its reduced cross-sectional area. This is particularly important for in-situ Scanning Electron Microscope (SEM) tensile tests, as they have to be conducted on smaller samples. In this study, a comprehensive experimental and numerical evaluation of the effect of specimen thickness (and the resulting number of grains within the cross-section) were conducted using in-situ SEM tensile test (on sub-millimeter thick samples) and ex-situ tensile tests (on samples of 0.68–5.9 mm thickness) and the results are compared with FEM simulations outcome. All tests were conducted at room temperature and the results are correlated to the number of grains within the thickness of specimens. The tensile test results indicated that even though the 0.2% proof stress and the tensile strength do not vary for the current range of thicknesses (with number of grains in the cross-section varying from 13 to 118), a difference in necking mechanism exists. Post tensile strength, thinner samples undergo more shear failure and diagonal localized necking whereas thicker samples experience more diffuse necking indicated by decreased area of shear failure at the edges and increased area of dimpled tensile failure at the center of the sample. FEM results complement the experimental findings by showing the formation of conjugated localized shear bands on the upper and lower surface in the 0.68 mm thick sample and shear bands combining to form singular shear bands in thicker samples. These results also confirm the validity of the in-situ SEM tensile tests conducted on thinner samples as long as the required minimum number of grains exist within the cross-section. DA - 2022/2// PY - 2022/2// DO - 10.1016/j.matchar.2021.111614 VL - 184 SP - SN - 1873-4189 KW - Alloy 709 KW - Tensile test KW - Size effect KW - Necking KW - Grain size KW - Finite element modeling ER - TY - JOUR TI - A Direct Comparison of Node and Element-Based Finite Element Modeling Approaches to Study Tissue Growth AU - Howe, Danielle AU - Dixit, Nikhil N. AU - Saul, Katherine R. AU - Fisher, Matthew B. T2 - JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME AB - Finite element analysis is a useful tool to model growth of biological tissues and predict how growth can be impacted by stimuli. Previous work has simulated growth using node-based or element-based approaches, and this implementation choice may influence predicted growth, irrespective of the applied growth model. This study directly compared node-based and element-based approaches to understand the isolated impact of implementation method on growth predictions by simulating growth of a bone rudiment geometry, and determined what conditions produce similar results between the approaches. We used a previously reported node-based approach implemented via thermal expansion and an element-based approach implemented via osmotic swelling, and we derived a mathematical relationship to relate the growth resulting from these approaches. We found that material properties (modulus) affected growth in the element-based approach, with growth completely restricted for high modulus values relative to the growth stimulus, and no restriction for low modulus values. The node-based approach was unaffected by modulus. Node- and element-based approaches matched marginally better when the conversion coefficient to relate the approaches was optimized based on the results of initial simulations, rather than using the theoretically predicted conversion coefficient (median difference in node position 0.042 cm versus 0.052 cm, respectively). In summary, we illustrate here the importance of the choice of implementation approach for modeling growth, provide a framework for converting models between implementation approaches, and highlight important considerations for comparing results in prior work and developing new models of tissue growth. DA - 2022/1/1/ PY - 2022/1/1/ DO - 10.1115/1.4051661 VL - 144 IS - 1 SP - SN - 1528-8951 ER - TY - JOUR TI - High piezoelectricity after field cooling AC poling in temperature stable ternary single crystals manufactured by continuous-feeding Bridgman method AU - Luo, Cong AU - Karaki, Tomoaki AU - Wang, Zhuangkai AU - Sun, Yiqin AU - Yamashita, Yohachi AU - Xu, Jiayue T2 - JOURNAL OF ADVANCED CERAMICS AB - Abstract After field cooling (FC) alternating current poling (ACP), we investigated the dielectric and piezoelectric properties of [001] pc -oriented 0.24Pb(In 1/2 Nb 1/2 )O 3 (PIN)-0.46Pb(Mg 1/3 Nb 2/3 )O 3 (PMN)-0.30PbTiO3 (PT) (PIMN-0.30PT) single crystals (SCs), which were manufactured by continuous-feeding Bridgman (CF BM) within morphotropic phase boundary (MPB) region. By ACP with 4 kV rms /cm from 100 to 70 °C, the PIMN-0.30PT SC attained high dielectric permittivity (ε 33 T /ε 0 ) of 8330, piezoelectric coefficient ( d 33 ) of 2750 pC/N, bar mode electromechanical coupling factor k 33 of 0.96 with higher phase change temperature ( T pc ) of 103 °C, and high Curie temperature ( T C ) of 180 °C. These values are the highest ever reported as PIMN- x PT SC system with T pc > 100 °C. The enhancement of these properties is attributed to the induced low symmetry multi-phase supported by phase analysis. This work indicates that FC ACP is a smart and promising method to enhance piezoelectric properties of relaxor-PT ferroelectric SCs including PIMN- x PT, and provides a route to a wide range of piezoelectric device applications. DA - 2022/1// PY - 2022/1// DO - 10.1007/s40145-021-0490-1 VL - 11 IS - 1 SP - 57-65 SN - 2227-8508 KW - field cooling (FC) alternating current poling (ACP) KW - PIMN-0 KW - 30PT KW - high piezoelectricity ER - TY - JOUR TI - Special Issue: The Behavior of Crystalline Materials: In Honor of Professor Hussein Zbib AU - Field, David AU - Garmestani, Hamid AU - Khraishi, Tariq AU - Zikry, Mohammed T2 - JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME AB - This special issue of the ASME Journal of the Engineering Materials and Technology is dedicated to the memory of our friend and colleague, Professor Hussein Zbib, who passed away in February 2020. Hussein was a past editor of this journal and was an internationally recognized research leader and an innovator in numerous aspects of mechanics of materials, such as dislocation dynamics, plasticity, and irradiated materials. The articles in this special issue, through the different contributions of his collaborators, colleagues, students, and friends, truly reflect the different research areas he impacted. Furthermore, these contributions underscore how his research interests, collaborations, and achievements fundamentally influenced the experimental and modeling accomplishments of the contributing authors.Hussein was a Professor in the School of Mechanical and Materials Engineering at Washington State University since 1988. As a director of the Computational Mechanics and Materials Science Laboratory, he conducted research in the field of multiscale theoretical modeling and predictions of the thermo-mechanical behavior of advanced materials. He developed models and theories used by materials scientists and engineers throughout the world, and his research significantly improved and elevated the fundamental understanding of the behavior of metals, alloys, and composites at different physical scales.His research group, for instance, developed models to simulate the behavior of a wide array of materials that are exposed to high doses of radiation. It was well known that such materials can deform and fail, but the mechanics and defect behavior were not well understood until Hussein and his coworkers developed a new class of computational tools based on innovative formulations related to dislocation dynamics. This was a crucial breakthrough, since dislocation dynamics is essentially now recognized as an established link between atomistic and continuum approaches.Hussein published more than 250 technical articles in leading journals, edited 12 books, and presented hundreds of invited talks and seminars. Over his career, he supervised and mentored more than 30 masters and doctoral students, six postdoctoral fellows, 11 visiting scholars, and 15 undergraduate research assistants. Many of his students went on to become internationally recognized researchers and leaders in academia, in industry, and at national laboratories.Hussein was a fellow of the American Association for the Advancement of Science and the ASME as well as an executive member of the Lebanese Academy of Science. He was a recipient of the 2010 Khan International Award for outstanding contribution to the field of plasticity. He also received research excellence awards from the Voiland College of Engineering and Architecture in 1994 and 2015 and from the School of Mechanical and Materials Engineering in 2000 at Washington State University. He was named a Regents Professor, the university's highest faculty title, in 2018. He also served as the director of the School of MME from 2003 to 2011. During his tenure as a school director, he played a significant role in expanding the faculty size, research expenditures, and private donations, and fostering partnerships with industries and national laboratories, such that the School is now recognized as a leading national mechanical engineering and materials science department.Hussein was born in Beirut, Lebanon, to Mustapha and Sahjouna Zbib, and his parents were from South Lebanon. He completed his schooling in Beirut, graduating from Aamlye Technical College. Zbib received his bachelor, masters, and Ph.D. in Mechanical Engineering and Engineering Mechanics from Michigan Technological University. He married Marcia Ann Rowe in Hancock, MI, on July 12, 1986, and in 1988, they moved to Pullman when Zbib accepted a position at WSU.Hussein enjoyed being with family and friends. He enjoyed cooking and dancing, and he and his wife Marcia were active in both the Palouse dance club and gourmet club. Zbib also enjoyed golfing, fishing, boating, reading, cross country skiing, table tennis, tennis, going to fine dining restaurants, and spending time at the gym exercising and swimming. Together he and his wife Marcia enjoyed traveling throughout the world.Hussein is survived by his wife Marcia, mother Sahjouna Zbib, two brothers Ali and Bilal Zbib, three sisters Fadia, Hana, and Iman Zbib, and many nieces and nephews. He was preceded in death by his father Mustapha Zbib, brother Hassan Zbib; and two sisters Ferial and Sanaa Zbib.Hussein was the model for a research innovator and an academic leader. All of us are missing Hussein; we will never forget him, his wisdom, his easy smile, and the twinkle in his eye. His spirit will always be with us as a guiding light in our lives. DA - 2022/1/1/ PY - 2022/1/1/ DO - 10.1115/1.4052487 VL - 144 IS - 1 SP - SN - 1528-8889 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85144510088&partnerID=MN8TOARS ER - TY - JOUR TI - Thermomechanical Microstructural Predictions of Fracture Nucleation of Zircaloy-4 Alloys With delta and e Hydride Distributions AU - Mohamed, I. AU - Hasan, T. AU - Zikry, M. A. T2 - JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME AB - Abstract A crystalline dislocation-density formulation that was incorporated with a nonlinear finite-element (FE) method was utilized to understand and to predict the thermomechanical behavior of an hexagonal closest packed (h.c.p.) zircaloy system with hydrides with either face-centered cubic (f.c.c.) or body-centered cubic (b.c.c.) hydrides. This formulation was then used with a recently developed fracture methodology that is adapted for finite inelastic strains and multiphase crystalline systems to understand how different microstructurally based fracture modes nucleate and propagate. The interrelated microstructural characteristics of the different crystalline hydride and matrix phases with the necessary orientation relationships (ORs) have been represented, such that a detailed physical understanding of fracture nucleation and propagation can be predicted for the simultaneous thermomechanical failure modes of hydride populations and the matrix. The effects of volume fraction, morphology, crystalline structure, and orientation and distribution of the hydrides on simultaneous and multiple fracture modes were investigated for radial, circumferential, and mixed distributions. Another key aspect was accounting for temperatures changes due to the effects of thermal conduction and dissipated plastic work and their collective effects on fracture. For hydrided aggregates subjected to high temperatures, thermal softening resulted in higher ductility due to increased dislocation-density activity, which led to higher shear strain accumulation and inhibited crack nucleation and growth. The predictions provide validated insights into why circumferential hydrides are more fracture-resistant than radial hydrides for different volume fractions and thermomechanical loading conditions. DA - 2022/1/1/ PY - 2022/1/1/ DO - 10.1115/1.4051687 VL - 144 IS - 1 SP - SN - 1528-8889 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85127542533&partnerID=MN8TOARS KW - zirconium h KW - c KW - p KW - matrix KW - fracture nucleation KW - radial and circumferential hydrides KW - crystalline orientations KW - mechanical behavior KW - microstructure property relationships KW - plastic behavior ER - TY - JOUR TI - Experiment-Based Modeling of Turbulent Flames with Inhomogeneous Inlets AU - Ranade, Rishikesh AU - Echekki, Tarek AU - Masri, Assaad R. T2 - Flow, Turbulence and Combustion DA - 2022/4// PY - 2022/4// DO - 10.1007/s10494-021-00304-8 UR - https://doi.org/10.1007/s10494-021-00304-8 KW - Data-based modeling KW - Kernel density estimation KW - Principal component analysis KW - Artificial neural networks ER - TY - JOUR TI - Ultrasonic frequency response of fiber Bragg grating under direct and remote adhesive bonding configurations AU - Navratil, Andrew AU - Wee, Junghyun AU - Peters, Kara T2 - MEASUREMENT SCIENCE AND TECHNOLOGY AB - Abstract Ultrasonic inspection based structural health monitoring is a powerful technique for damage detection in a structure. Ultrasonic waves are often excited at different frequencies to detect damages of different sizes, therefore understanding the frequency response of the sensor can be used to optimize the sensor performance. Fiber Bragg gratings (FBGs) are widely used for this ultrasound collection. The sensitivity of FBGs to a particular ultrasonic frequency is a function of the FBG length and the ultrasonic wavelength. Recently the authors demonstrated that its ultrasound sensitivity is improved for some conditions when the FBG is bonded at a distance away from the adhesive bond, referred to as remote bonding. However, the frequency response of this configuration has not been studied. Therefore, in this paper we measure and compare the ultrasonic frequency responses between a conventional directly bonded FBG and remotely bonded FBG. In theory, the FBG sensitivity varies as a function of ultrasound wavelength-to-grating length ( λ / L ) ratio. Therefore, for this experimental study, we maintain L constant and vary λ by changing the frequency of the input ultrasonic waves. We demonstrate that there is a region, below a cut-off values of λ / L , for which the remotely bonded FBG output has a higher sensitivity to the Lamb wave amplitude than the directly bonded FBG. The exact value of this λ / L cut-off depends on the mechanical properties of the structure, the windowing of the input Lamb wave, and the FBG properties. We also demonstrate that windowing the Lamb wave excitation signal has a similar affect to apodizing the FBG sensor in modifying the sensitivity response curve. DA - 2022/1// PY - 2022/1// DO - 10.1088/1361-6501/ac2fea VL - 33 IS - 1 SP - SN - 1361-6501 KW - structural health monitoring KW - non-destructive evaluation KW - ultrasonic inspection KW - optical fiber sensor KW - fiber Bragg grating ER - TY - JOUR TI - Object Recognition via Evoked Sensory Feedback during Control of a Prosthetic Hand AU - Vargas, Luis AU - Huang, He AU - Zhu, Yong AU - Hu, Xiaogang T2 - IEEE ROBOTICS AND AUTOMATION LETTERS AB - Haptic and proprioceptive feedback is critical for sensorimotor integration when we use our hand to perform daily tasks. Here, we evaluated how externally evoked haptic and proprioceptive feedback and myoelectric control strategies affected the recognition of object properties when participants controlled a prosthetic hand. Fingertip haptic sensation was elicited using a transcutaneous nerve stimulation grid to encode the prosthetic's fingertip forces. An array of tactors elicited patterned vibratory stimuli to encode tactile-proprioceptive kinematic information of the prosthetic finger joint. Myoelectric signals of the finger flexor and extensor were used to control the position or velocity of joint angles of the prosthesis. Participants were asked to perform object property (stiffness and size) recognition, by controlling the prosthetic hand with concurrent haptic and tactile-proprioceptive feedback. With the evoked feedback, intact and amputee participants recognized the object stiffness and size at success rates ranging from 50% to 100% in both position and velocity control with no significant difference across control schemes. Our findings show that evoked somatosensory feedback in a non-invasive manner can facilitate closed-loop control of the prosthetic hand and allowed for simultaneous recognition of different object properties. The outcomes can facilitate our understanding on the role of sensory feedback during bidirectional human-machine interactions, which can potentially promote user experience in object interactions using prosthetic hands. DA - 2022/1// PY - 2022/1// DO - 10.1109/LRA.2021.3122897 VL - 7 IS - 1 SP - 207-214 SN - 2377-3766 KW - Haptic and proprioceptive sensation KW - transcutaneous nerve stimulation KW - vibrotactile stimulation KW - stiffness recognition KW - size recognition ER - TY - JOUR TI - Dielectric and mechanical properties of hypersonic radome materials and metamaterial design: A review AU - Kenion, Taylor AU - Yang, Ni AU - Xu, Chengying T2 - JOURNAL OF THE EUROPEAN CERAMIC SOCIETY AB - This review paper examines ten current ceramic radome materials under research and development and provides a comprehensive overview of available high temperature and high frequency data from literature. An examination of metamaterials for radio-frequency transparent radomes is given and our preliminary experimental results of a high-temperature metamaterial design are presented. The next-generation hypersonic vehicles’ radome temperatures will exceed 1000℃ and speeds will exceed Mach 5. An ideal radome material will have a high flexural strength, low dielectric constant and loss tangent, and high resistance to thermal shock and corrosion. The microstructural effect on the dielectric and mechanical properties and the effects of environmental factors such as rain are discussed. The impact of metamaterial structure on key radome factors such as boresight error, gain, and polarization is examined. After examining the associated benefits with the use of metamaterials, our preliminary results for a potential high-temperature metamaterial design are presented. DA - 2022/1// PY - 2022/1// DO - 10.1016/j.jeurceramsoc.2021.10.006 VL - 42 IS - 1 SP - 1-17 SN - 1873-619X KW - Radome KW - Hypersonic KW - Ceramic KW - High temperature KW - Review KW - Metamaterial ER - TY - JOUR TI - Investigation of deep learning methods for efficient high-fidelity simulations in turbulent combustion AU - Gitushi, Kevin M. AU - Ranade, Rishikesh AU - Echekki, Tarek T2 - COMBUSTION AND FLAME AB - Turbulent combustion modeling often faces a trade-off between the so-called flamelet-like models and PDF-like models. Flamelet-like models, are characterized by a choice of a limited set of prescribed moments, which are transported to represent the manifold of the composition space and its statistics. PDF-like approaches are designed to directly evaluate the closure terms associated with the nonlinear chemical source terms in the energy and species equations. They generate data on the fly, which can be used to accelerate the simulation of PDF-like based models. Establishing key ingredients for implementing acceleration schemes for PDF-like methods by constructing flamelet-like models on the fly can potentially result in computational saving while maintaining the ability to resolve closure terms. These ingredients are investigated in this study. They include a data-based dimensional reduction of the composition space to a low-dimensional manifold using principal component analysis (PCA). The principal components (PCs) serve as moments, which characterize the manifold; and conditional means of the thermo-chemical scalars are evaluated in terms of these PCs. A second ingredient involves adapting a novel deep learning framework, DeepONet, to construct joint PCs’ PDFs as alternative methods to presumed shapes common in flamelet-like approaches. We also investigate whether the rotation of the PCs into independent components (ICs) can improve their statistical independence. The combination of these ingredients is investigated using experimental data based on the Sydney turbulent nonpremixed flames with inhomogeneous inlets. The combination of constructed PDFs and conditional mean models are able to adequately reproduce unconditional statistics of thermo-chemical scalars, and establish acceptable statistical independence between the PCs, which simplify further the modeling of the joint PCs’ PDFs. DA - 2022/2// PY - 2022/2// DO - 10.1016/j.combustflame.2021.111814 VL - 236 SP - SN - 1556-2921 UR - https://doi.org/10.1016/j.combustflame.2021.111814 KW - DeepONet KW - Kernel density estimation KW - Principal component analysis KW - Independent component analysis ER - TY - JOUR TI - Direct measurement of rate-dependent mode I and mode II traction-separation laws for cohesive zone modeling of laminated glass AU - Poblete, Felipe R. AU - Mondal, Kunal AU - Ma, Yinong AU - Dickey, Michael D. AU - Genzer, Jan AU - Zhu, Yong T2 - COMPOSITE STRUCTURES AB - This paper reports a combined experimental-modeling study on the adhesion at glass/poly(vinyl butyral) (PVB) interfaces. PVB is a critical component in laminated glasses that provides impact resistance and prevents spallation in the event of glass breakage. We characterize the mode I (normal) and mode II (shear) interfacial fracture behaviors in glass/PVB/glass laminates and obtained independent cohesive (traction–separation) laws for the two modes. We observe a pronounced rate dependence of both traction-separation laws. Specifically, with increasing loading rate, the interfacial stiffness, the peak stress, and the fracture toughness increase while the critical opening or shear displacement decreases. These measured traction-separation laws are used as inputs in finite element analysis to predict the mechanical behavior of the peel test, which agrees reasonably well with the experimental results. Finite element analysis of a glass laminate subjected to impact loading demonstrates how the measured interfacial properties can be used to predict the mechanical behavior and failure of laminated glass. DA - 2022/1/1/ PY - 2022/1/1/ DO - 10.1016/j.compstruct.2021.114759 VL - 279 SP - SN - 1879-1085 KW - Glass KW - PVB KW - Interfacial mechanics KW - Cohesive zone modeling KW - Adhesion KW - Shear strength ER -