@article{adekunle_li_vallabh_seyam_2024, title={Assessment of Adhesion in Woven Fabric-Reinforced Laminates (FRLs) Using Novel Yarn Pullout in Laminate Test}, url={https://doi.org/10.3390/jcs8070242}, DOI={10.3390/jcs8070242}, abstractNote={Fiber-reinforced laminates with flexibility (FRLs) are becoming increasingly crucial across diverse sectors due to their adaptability and outstanding mechanical attributes. Their ability to deliver high performance relative to their weight makes them indispensable in lighter-than-air (LTA) applications, such as aerostats, inflatable antennas, surge bladders, gas storage balloons, life rafts, and other related uses. This research delved into employing woven fabrics as the reinforcement material and explored how their specific parameters, like fiber type, fabric count (warp thread density × weft thread density), fabric areal density, and fabric cover influence the bonding and mechanical properties of laminates. A thorough analysis encompassing standard T-peel (ASTM standard D1876) and a newly proposed yarn pullout in laminate test were conducted on laminates fabricated with various woven reinforcements, each with its unique specifications. The T-peel test was utilized to gauge the adhesive strength between FRL components, offering crucial insights into interfacial bonding within the laminates. Nevertheless, challenges exist with the T-peel test, including instances where the adherents lack the strength to withstand rupture, resulting in unsuccessful peel propagation and numerous outliers that necessitate costly additional trials. Thus, our research group introduced a novel yarn pullout in laminate test to accurately assess adhesion in FRLs. This study uncovered correlations between both adhesion tests (T-peel and yarn pullout in laminate), indicating that the innovative yarn pullout in laminate test could effectively substitute for characterizing adhesion in FRLs. Furthermore, the findings unveiled a complex relationship between woven fabric specifications and laminate properties. We noted that variations in fiber type, yarn linear density, and adhesive type significantly impacted adhesion strength. For instance, Kevlar exhibited markedly superior adhesion compared to Ultra-High Molecular Weight Polyethylene (UHMWPE) when paired with Thermoplastic Polyurethane (TPU) adhesive, whereas UHMWPE demonstrated better adhesion with Ethylene Vinyl Acetate (EVA). Moreover, the adhesion quality lessened as fabric count increased for the same adhesive quantity. These discoveries carry practical implications for material selection and design across industries, from automotive to aerospace, offering avenues to enhance FRL performance.}, journal={Journal of Composites Science}, author={Adekunle, Feyi and Li, Ang and Vallabh, Rahul and Seyam, Abdel-Fattah M.}, year={2024}, month={Jun} }
 @article{tahir_li_moore_ford_theyson_seyam_2024, title={Development of Eco-Friendly Soy Protein Fiber: A Comprehensive Critical Review and Prospects}, volume={12}, ISSN={2079-6439}, url={http://dx.doi.org/10.3390/fib12040031}, DOI={10.3390/fib12040031}, abstractNote={In the first half of the twentieth century, scientific communities worldwide endeavored to diminish dependence on expensive and scarce animal fibers like wool and silk. Their efforts focused on developing regenerated protein fibers, including soy, zein, and casein, to provide comparable benefits to natural protein fibers, such as lustrous appearance, warmth, and a soft feel. The popularity and cost-effectiveness of mass-produced petroleum-based synthetic polymer fibers during World War II diminished interest in developing soy protein fiber. Realizing the ecological degradation caused by fossil fuels and their derived products, a renewed drive exists to explore bio-based waste materials like soy protein. As a fast-growing crop, soy provides abundant byproducts with opportunities for waste valorization. The soybean oil extraction process produces soy protein as a byproduct, which is a highly tunable biopolymer. Various functional groups within the soy protein structure enable it to acquire different valuable properties. This review critically examines scholarly publications addressing soy protein fiber developmental history, soy protein microstructure modification methods, and soy protein fiber spinning technologies. Additionally, we provide our scientific-based views relevant to overcoming the limitations of previous work and share prospects to make soy protein byproducts viable textile fibers.}, number={4}, journal={Fibers}, publisher={MDPI AG}, author={Tahir, Muneeb and Li, Ang and Moore, Marguerite and Ford, Ericka and Theyson, Thomas and Seyam, Abdel-Fattah M.}, year={2024}, month={Mar}, pages={31} }
 @article{chen_sung_shen_tallent_barker_li_2022, title={Bit-GraphBLAS: Bit-Level Optimizations of Matrix-Centric Graph Processing on GPU}, ISSN={["1530-2075"]}, DOI={10.1109/IPDPS53621.2022.00056}, abstractNote={In a general graph data structure like an adjacency matrix, when edges are homogeneous, the connectivity of two nodes can be sufficiently represented using a single bit. This insight has, however, not yet been adequately exploited by the existing matrix-centric graph processing frameworks. This work fills the void by systematically exploring the bit-level representation of graphs and the corresponding optimizations to the graph operations. It proposes a two-level representation named Bit-Block Compressed Sparse Row (B2SR) and presents a series of optimizations to the graph operations on B2SR by leveraging the intrinsics of modern GPUs. Evaluations on NVIDIA Pascal and Volta GPUs show that the optimizations bring up to 40× and 6555× for essential GraphBLAS kernels SpMV and SpGEMM, respectively, making GraphBLAS-based BFS accelerate up to 433×, SSSP, PR, and CC up to 35×, and TC up to 52×.}, journal={2022 IEEE 36TH INTERNATIONAL PARALLEL AND DISTRIBUTED PROCESSING SYMPOSIUM (IPDPS 2022)}, author={Chen, Jou-An and Sung, Hsin-Hsuan and Shen, Xipeng and Tallent, Nathan and Barker, Kevin and Li, Ang}, year={2022}, pages={515–525} }
 @article{li_danladi_vallabh_yakubu_ishiaku_seyam_2022, title={Coir Fibers and Micronized Rubber Modified Asphalt Binder}, volume={12}, journal={Journal of Textile & Apparel Technology & Management (JTATM}, author={Li, Ang and Danladi, Abdu A. and Vallabh, Rahul and Yakubu, Mohammed K. and Ishiaku, Umar and Seyam, Abdel-Fattah M.}, year={2022}, pages={1} }
 @article{li_vallabh_bradford_kim_seyam_2022, title={Development of hull material for high-altitude airship: A parametric study}, volume={41}, ISSN={0731-6844 1530-7964}, url={http://dx.doi.org/10.1177/07316844211054852}, DOI={10.1177/07316844211054852}, abstractNote={ The development of hull material with ideal properties to meet all the operation requirements has posed the greatest challenge to flying the airship at high altitude for extended periods. Materials developed in our previous study with a laminated structure achieved high strength-to-weight ratio and excellent gas barrier property at a relatively low total weight. To optimize this novel design and obtain a more comprehensive understanding of the laminate properties, a parametric study involving lamination process parameters (temperature and time), and laminate structural parameter (reinforcement fabric construction), was conducted. The effects of lamination parameters on tensile, peel, tear and helium permeability tests were carried out to assess the laminates. It was found that the tensile strength of the laminate is predominantly determined by the fabric reinforcement material properties. The peel and tear strength results showed that increasing the lamination temperature from 185 °C to 200 °C improved respective strength values. Additionally, the analysis of failure modes and tear propagation suggested that laminate samples with progressive failure have better tear resistant property over those with brutal failure. Extremely low helium permeability was achieved, yet the gas barrier property was not affected by the lamination process parameters and fabric type. }, number={11-12}, journal={Journal of Reinforced Plastics and Composites}, publisher={SAGE Publications}, author={Li, Ang and Vallabh, Rahul and Bradford, Philip D and Kim, David and Seyam, Abdel-Fattah M}, year={2022}, month={Jan}, pages={444–458} }
 @article{szőke_devenport_borgoltz_alexander_hari_glegg_li_vallabh_seyam_2022, title={Investigating the Aeroacoustic Properties of Porous Fabrics}, volume={60}, ISSN={0001-1452 1533-385X}, url={http://dx.doi.org/10.2514/1.j061385}, DOI={10.2514/1.J061385}, abstractNote={The aeroacoustic properties of porous fabrics are investigated experimentally with the goal of finding a fabric that serves as an improved interface between wind tunnel flow and quiescent conditions. A total number of eight porous fabrics were investigated, namely, four glass fiber fabrics, two plain-weave Kevlar fabrics, and two modified plain Kevlar fabrics with their pores irregularly clogged. Two custom-made rigs were used to quantify the transmission loss (TL) and self-noise of all fabrics. The pores were found to serve as a low-resistance gateway for sound to pass through, hence enabling a low TL. The TL was found to increase with decreasing open area ratio (OAR), whereas other fabric properties had a minor impact on TL. The thread density was found to be a primary factor in determining the frequency range of porous fabrics’ self-noise, with the OAR potentially playing a secondary role in the self-noise levels. Fabrics with irregular pore distribution showed a more broadband self-noise signature associated with lower frequencies compared to fabrics with periodic pore patterns. Overall, fabrics with an irregular pore distribution or fabrics with increased thread density were identified as two potential ways to obtain superior aeroacoustic behavior compared to commonly used Kevlar fabrics.}, number={6}, journal={AIAA Journal}, publisher={American Institute of Aeronautics and Astronautics (AIAA)}, author={Szőke, Máté and Devenport, William J. and Borgoltz, Aurélien and Alexander, W. Nathan and Hari, Nandita and Glegg, Stewart A. L. and Li, Ang and Vallabh, Rahul and Seyam, Abdel-Fattah M.}, year={2022}, month={Jun}, pages={3651–3660} }
 @article{li_danladi_vallabh_yakubu_ishiaku_theyson_seyam_2021, title={Cellulose Microfibril and Micronized Rubber Modified Asphalt Binder}, volume={9}, ISSN={["2079-6439"]}, url={https://doi.org/10.3390/fib9040025}, DOI={10.3390/fib9040025}, abstractNote={Cellulose microfibrils (CMFs) and micronized rubber powder (MRP) can be derived from low or negative-cost agricultural/industrial waste streams and offer environment-friendly and cost-effective pathways to develop engineering products. This study investigated the efficacy of adding these micromodifiers on the performance characteristics of asphalt binders. In this work, samples were produced using a mixture of slow-setting anionic asphalt emulsion with various combinations of MRP (at 0, 2 and 10 wt %) and four types of CMFs (hydrophobic and hydrophilic with crystalline ratios of 86% and 95%) at 0, 2 and 5 wt %. The performance of modified asphalt samples was assessed by penetration depth (PD), softening point (SP), and penetration index (PI). Linear regression analysis showed that adding CMFs and/or MRP reduced PD and increased SP values. The type of CMFs significantly affected the performance, which becomes more distinct with the increased weight content of CMFs. While hydrophilic CMFs caused increases in SP and PI values, no clear trend was seen to determine the effect of CMF crystallinity. It was also discovered that the combined addition of CMF and MRP achieved similar PI values at lower total weight content compared to using MRP alone.}, number={4}, journal={FIBERS}, publisher={MDPI AG}, author={Li, Ang and Danladi, Abdu A. and Vallabh, Rahul and Yakubu, Mohammed K. and Ishiaku, Umar and Theyson, Thomas and Seyam, Abdel-Fattah M.}, year={2021}, month={Apr} }
 @article{vallabh_li_bradford_kim_seyam_2021, title={Ultra-lightweight fiber-reinforced envelope material for high-altitude airship}, volume={113}, ISSN={0040-5000 1754-2340}, url={http://dx.doi.org/10.1080/00405000.2021.1948695}, DOI={10.1080/00405000.2021.1948695}, abstractNote={Abstract In this work, fiber-reinforced laminates for the envelope (hull) of high-altitude airships were developed using a novel design concept utilizing ethylene vinyl alcohol (EVOH) as the adhesive component layer with high gas barrier properties. The other component layers of the laminates included poly(p-phenylene benzobisoxazole) (Zylon®) fabric, metalized Mylar® (polyester) and metallized Kapton® (polyimide). The envelope materials were developed in two different strength categories. In the first category, three laminate designs were developed with strength ranging from 945–970 N/cm. The second group had one laminate design with a strength of 702 N/cm. These laminates with basis weights ranging from 103–113 g/m2, are the lightest envelope materials developed to date. As a function of their high strength and low basis weights, the new envelope materials have significantly higher specific strength (ranging from 911–925 kN.m/kg) compared to other envelope constructions published in the open literature. Other outstanding properties of the laminates include low helium permeability ranging from 0.4–8.0 cc/m2.24 hr.1 atm, high tear strength, UV and visible light (UV–Vis) resistance, and high creep resistance.}, number={9}, journal={The Journal of The Textile Institute}, publisher={Informa UK Limited}, author={Vallabh, Rahul and Li, Ang and Bradford, Philip D. and Kim, David and Seyam, Abdel-Fattah M.}, year={2021}, month={Jul}, pages={1799–1805} }
 @article{wang_yildiz_li_aly_qiu_jiang_pui_chen_bradford_2020, title={High temperature carbon nanotube - Nanofiber hybrid filters}, volume={236}, ISSN={["1873-3794"]}, DOI={10.1016/j.seppur.2019.116255}, abstractNote={Novel hybrid filters composed of aligned carbon nanotube (CNT) sheets, sandwiched between electrospun polyimide (PI) nanofiber membranes serving as the supporting layers, were fabricated for the capture of fine particles. The CNT sheets and PI nanofiber membranes were thermally bonded together by melting electrospun polyetherimide (PEI) nanofibers. Two different kinds of filter structures were prepared, where multiple layers of aligned CNT sheets were either stacked together on top of each other or separated from each other by a PEI layer. The filtration performance tests showed that the filtration efficiency increased with increasing number of CNT sheets. The maximum filtration efficiency reached 99.99% at 5.3 cm/s face velocity for 0.3 μm particles by the 4-layer CNT filter, while the pressure drop was only 120 Pa. In mechanical testing, the CNT sheets also reinforced the hybrid filters, even though the PI nanofiber membrane already had relatively high mechanical properties. The tensile strength of the 4-layer CNT hybrid filters was 9 MPa, reaching the highest tier of strength reported for nanofiber membranes. In addition to high efficiency and low pressure drop, the hybrid all-nanofiber filters are also targeted for use in hot gas filtration applications where temperatures reach 200–250 °C.}, journal={SEPARATION AND PURIFICATION TECHNOLOGY}, publisher={Elsevier}, author={Wang, Qiannan and Yildiz, Ozkan and Li, Ang and Aly, Karim and Qiu, Yiping and Jiang, Qiuran and Pui, David Y. H. and Chen, Sheng-Chieh and Bradford, Philip D.}, year={2020}, month={Apr} }
 @article{li_mikkel vertergaard franden_abdel-fattah mohamed seyam_ang_2019, title={A lighter-than-air vehicle with a hull, a laminate for such hull and a method of production of such laminate}, note={DK Patent 179553 B1}, author={Li, Rahul Vallabh and Mikkel Vertergaard Franden, David Kim and Abdel-Fattah Mohamed Seyam, Philip David Bradford and Ang}, year={2019} }
 @book{kim_vestergaard_bradford_seyam_vallabh_li_2019, title={A lighter-than-air vehicle with hull, a laminate, for such hull and a method of production of such laminate}, number={DK 179553 B1}, author={Kim, D. and Vestergaard, M. and Bradford, P.D. and Seyam, A.M. and Vallabh, R. and Li, Ang}, year={2019}, month={Feb} }
 @article{li_vallabh_bradford_seyam_2019, title={Textile Laminates for High-altitude Airship Hull Materials-a review.}, volume={11}, number={1}, journal={Journal of Textile & Apparel Technology & Management (JTATM)}, author={Li, Ang and Vallabh, Rahul and Bradford, Philip D and Seyam, Abdel-Fattah M}, year={2019} }
 @article{aly_li_bradford_2018, title={In-situ monitoring of woven glass fiber reinforced composites under flexural loading through embedded aligned carbon nanotube sheets}, volume={52}, number={20}, journal={Journal of Composite Materials}, publisher={SAGE Publications Sage UK: London, England}, author={Aly, Karim and Li, Ang and Bradford, Philip D}, year={2018}, pages={2777–2788} }
 @article{aly_li_bradford_2017, title={Compressive piezoresistive behavior of carbon nanotube sheets embedded in woven glass fiber reinforced composites}, volume={116}, ISSN={["1879-1069"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85006298233&partnerID=MN8TOARS}, DOI={10.1016/j.compositesb.2016.11.002}, abstractNote={Due to the difficulties associated with performing compression tests and the complex nature of compression failure, the number of studies that have examined the piezoresistive response of carbon nanotube (CNT) sensing networks in composites under compression loading has been limited. This paper introduces a novel technique for embedding aligned sheets of two millimeter long, interconnected CNTs into the interlaminar region of laminated composite structures to assess the potential of the CNT sheets to function as strain sensing materials for composite structures subjected to axial compression loading. Quasi-static and cyclic compression mechanical loading tests were accompanied by real time electrical resistance change data acquisition and the results suggested that the CNT sheet sensing material composed of six CNT sheets layers exhibited improved sensitivity, stability and repeatability which are vital properties for any successful health monitoring technique. The coupons with six CNT sheets layers embedded exhibited piezoresistivity that showed some linearity in tension and was nonlinear in compression. This piezoresistive response was characterized as anti-symmetric around zero strain all the way until fracture.}, journal={COMPOSITES PART B-ENGINEERING}, publisher={Elsevier}, author={Aly, Karim and Li, Ang and Bradford, Philip D.}, year={2017}, month={May}, pages={459–470} }
 @article{fang_li_yildiz_shao_bradford_ghosh_2017, title={Enhanced anisotropic response of dielectric elastomer actuators with microcombed and etched carbon nanotube sheet electrodes}, volume={120}, ISSN={["1873-3891"]}, DOI={10.1016/j.carbon.2017.05.067}, abstractNote={Dielectric elastomers (DE), also known as dielectric electroactive polymers offer tremendous potential in a wide-ranging applications including microrobotics and wearable responsive systems. The real-world application of DEs, however, has been limited by a number of factors, including facile means of producing directional stress/strain. As a critical component of the DE actuator, the electrodes should have high electrical conductance under finite in-plane deformation, good electromechanical stability, and ease of shaping based on the design requirements. In this work we investigate highly aligned carbon nanotube (CNT) sheets as electrodes in DE actuators to yield anisotropic electromechanical response. The morphology of CNT sheets were altered by microcombing and selective laser etching to enhance mechanical anisotropy. The enhancement of CNT sheets alignment results in almost pure unidirectional strain of 33% at a relatively moderate electric field. The results demonstrate that the deformation anisotropy of DE actuators can be significantly improved by directional laser etching of the electrodes rather than microcombing alone.}, journal={CARBON}, publisher={Elsevier}, author={Fang, Xiaomeng and Li, Ang and Yildiz, Ozkan and Shao, Huiqi and Bradford, Philip D. and Ghosh, Tushar K.}, year={2017}, month={Aug}, pages={366–373} }
 @article{aly_li_bradford_2016, title={Strain sensing in composites using aligned carbon nanotube sheets embedded in the interlaminar region}, volume={90}, ISSN={["1878-5840"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84983749060&partnerID=MN8TOARS}, DOI={10.1016/j.compositesa.2016.08.003}, abstractNote={This paper introduces a novel technique for embedding aligned sheets of two millimeters long, interconnected CNTs into the interlaminar region of composite structures. The potential of these embedded CNT sheets to function as damage detecting and strain sensing elements was demonstrated via various mechanical tests that were accompanied by real time electrical resistance change data acquisition. The experimental results suggested that the CNT sheet sensitivity could be further enhanced by an oxygen plasma treatment and also by pre-straining the CNT sheets before embedding them. The samples containing two CNT sheets layers exhibited long term stability, sensitivity and repeatability which are vital features for health monitoring.}, journal={COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING}, publisher={Elsevier}, author={Aly, Karim and Li, Ang and Bradford, Philip D.}, year={2016}, month={Nov}, pages={536–548} }
 @article{aly_li_bradford_2016, title={Strain sensing in composites using aligned carbon nanotube sheets embedded in the interlaminar region Part A Applied science and manufacturing}, author={Aly, Karim and Li, Ang and Bradford, Philip D}, year={2016} }
 @article{li_bogdanovich_bradford_2015, title={Aligned carbon nanotube sheet piezoresistive strain sensors}, volume={24}, ISSN={["1361-665X"]}, DOI={10.1088/0964-1726/24/9/095004}, abstractNote={Carbon nanotubes (CNTs) have a unique set of properties that may be useful in the production of next generation structural health monitoring composites. This research introduces a novel CNT based material system for strain and damage sensing applications. An aligned sheet of interconnected CNTs was drawn from a chemical vapor deposition grown CNT array and then bonded to the surface of glass fiber/epoxy composite coupons. Various types of mechanical tests were conducted, accompanied by real-time electrical data acquisition, in order to evaluate the electro-mechanical behavior of the developed sensing material. Specimens were loaded in the longitudinal and transverse CNT sheet orientations to investigate the anisotropy of the piezoresistive effect. The CNT sheets exhibited good sensing stability, linearity, sensitivity and repeatability within a practical strain range; which are crucial sensor features for health monitoring. It was also demonstrated that the CNT orientation in the sheet had a dramatic effect on the sensitivity, thus validating the usefulness of this sensing material for directional strain/damage monitoring. Finally, pre-straining of the CNT sheet sensors was conducted to further enhance the linearity of electro-mechanical response and long-term stability of the sensors during cyclic loading.}, number={9}, journal={SMART MATERIALS AND STRUCTURES}, author={Li, Ang and Bogdanovich, Alexander E. and Bradford, Philip D.}, year={2015}, month={Sep} }
 @article{li_bogdanovich_bradford_2015, title={Aligned carbon nanotube sheet piezoresistive strain sensors}, volume={24}, number={9}, journal={Smart Materials and Structures}, publisher={IOP Publishing}, author={Li, Ang and Bogdanovich, Alexander E and Bradford, Philip D}, year={2015}, pages={095004} }
 @book{bogdanovich_bradford_stahl_li_2015, title={Multifunctional Shear Pressed CNT Sheets for Strain Sensing and Composite Joint Toughening}, institution={NORTH CAROLINA STATE UNIV AT RALEIGH}, author={Bogdanovich, Alexander E and Bradford, Philip D and Stahl, James J and Li, Ang}, year={2015} }
 @inproceedings{li_2015, title={Strain Sensing in Fiberglass Textile Composites and Joints Using Carbon Nanotube Sheets}, booktitle={12th International Conference on Textile Composites}, author={Li, Ang}, year={2015}, month={May} }
 @article{faraji_stano_yildiz_li_zhu_bradford_2015, title={Ultralight anisotropic foams from layered aligned carbon nanotube sheets}, volume={7}, ISSN={["2040-3372"]}, DOI={10.1039/c5nr03899e}, abstractNote={A novel nanofabrication method is demonstrated to produce large size, elastically resilient, ultra-low density carbon nanotube foams (3.8 mg cm−3) with anisotropic and tunable properties. Potential applications of this unique material are explored.}, number={40}, journal={NANOSCALE}, publisher={Royal Society of Chemistry}, author={Faraji, Shaghayegh and Stano, Kelly L. and Yildiz, Ozkan and Li, Ang and Zhu, Yuntian and Bradford, Philip D.}, year={2015}, pages={17038–17047} }
 @article{li_stahl_bogdanovich_bradford, title={STRAIN SENSING IN FIBERGLASS TEXTILE COMPOSITES AND JOINTS USING CARBON NANOTUBE SHEETS}, author={Li, Ang and Stahl, James and Bogdanovich, Alexander and Bradford, Philip D} }
 @article{aly_li_bradford, title={Strain and Damage Sensing in Composites via Embedded CNT Sheets}, author={Aly, Karim and Li, Ang and Bradford, Philip D} }