@article{wall_parish_dixon_hawari_liu_breon_2023, title={Irradiation of ultrasonic sensors and adhesive couplants for application in light water reactor primary loop piping and components}, volume={414}, ISSN={["1872-759X"]}, DOI={10.1016/j.nucengdes.2023.112594}, abstractNote={The Electric Power Research Institute (EPRI) Nuclear Sector and US Department of Energy Light Water Reactor Sustainability Program are committed to engaging in research and development endeavors to address materials aging issues specific to long term operation of light water power reactors. To this effect, EPRI launched an industry initiative to develop nondestructive evaluation systems for online monitoring of existing cracks in light water reactor primary coolant loop piping and components. One of the goals of this initiative is to develop a sensor system (or systems) that can determine nondestructively if cracks are growing or arrested and, in the case of the former, to characterize their growth rates. A missing component of this initiative is an experimental assessment of how sensors and adhesive couplants will perform in service when exposed to chronic energetic neutron radiation, particularly at the primary coolant loop hot and cold leg dissimilar metal welds, which join the primary loop piping to the reactor pressure vessel and reside in the vicinity of the reactor core. The objective of this experimental study was to determine how ultrasonic transducers and adhesive couplants perform when exposed to irradiation in a test reactor to simulate and accelerate in-service exposure. To achieve this objective, the signal stability of piezoelectric transducers and performance of adhesive couplants as a function of accumulated fast neutron fluence were characterized by collecting ultrasonic data in-situ during irradiation. Of particular interest were the ultrasonic signal quality and time decay of the amplitude of acoustic reflections as a function of fast neutron fluence. The results of the study showed that, of the 8 transducer/substrate sample assemblies tested, only 3 generated usable ultrasonic signals through the conclusion of the irradiation campaign. It was found that high temperature epoxy tends to ultrasonically couple the sensors to the substrates better than three types of refractory ceramic cements studied, as is supported by post irradiation examination. The results obtained through this experimental study will be utilized in the achievement of the overall goal of development of a sensor system to perform online monitoring of primary loop components. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE AC05-00OR22725 with the US Department of Energy (DOE). The publisher acknowledges the US government license to provide public access under the DOE Public Access Plan (https://energy.gov/downloads/doe-public-access-plan [energy.gov]).}, journal={NUCLEAR ENGINEERING AND DESIGN}, author={Wall, James J. and Parish, Chad M. and Dixon, J. Travis and Hawari, Ayman I. and Liu, Ming and Breon, Luke}, year={2023}, month={Dec} }
 @article{burba_feightner_liu_hawari_2022, title={The Effect of Fluorinated Solvents on the Physicochemical Properties, Ionic Association, and Free Volume of a Prototypical Solvate Ionic Liquid}, ISSN={["1439-7641"]}, DOI={10.1002/cphc.202100548}, abstractNote={Solvate ionic liquid synthesis and properties depend on a delicate balancing of cation-solvent and cation-anion interactions to produce materials containing only cation-solvent complexes and solvent-separated anions. Most SILs meeting these characteristics fall within the paradigm of oligomeric ethylene oxides and lithium salts. Targeted functionalization of solvent molecules to achieve desired properties is a relatively unexplored avenue of research. We explore solvent fluorination for a prototypical SIL based on lithium bis(trifluoromethylsulfonyl)imide (LiNTf2) and triethylene glycol (TEG). In the first experiment, TEG is partially substituted with 2,2,4,4,5,5,7,7-octafluoro-3,6-dioxaoctane-1,8-diol (FTEG). This leads to a decrease in ionic conductivity and proliferation of Li(NTf2)2- species. Both results suggest FTEG does not readily coordinate Li+ ; a conclusion that is reinforced by computational studies of [(TEG)1Li]+ and [(FTEG)1Li]+ cation stabilities. A second experiment adds FTEG as a diluent to [(TEG)1Li]NTf2. This places FTEG and TEG in competition to coordinate a limited number of Li+ ions. The resulting mixtures exhibit conductivity and viscosity enhancements over the parent SIL and minimal changes in ion speciation due to the poor Li+ binding by FTEG. Positron annihilation lifetime spectroscopic studies point to increased amounts of free volume upon dilution of FTEG. This likely explains the origin of the conductivity enhancement.}, journal={CHEMPHYSCHEM}, author={Burba, Christopher M. and Feightner, Kylie and Liu, Ming and Hawari, Ayman}, year={2022}, month={Jan} }
 @article{pan_jin_ghadiyaram_kaur_miller_ta_liu_fan_mahn_gorthi_et al._2020, title={Cohesin SA1 and SA2 are RNA binding proteins that localize to RNA containing regions on DNA}, volume={48}, ISSN={["1362-4962"]}, url={http://dx.doi.org/10.1093/nar/gkaa284}, DOI={10.1093/nar/gkaa284}, abstractNote={Abstract Cohesin SA1 (STAG1) and SA2 (STAG2) are key components of the cohesin complex. Previous studies have highlighted the unique contributions by SA1 and SA2 to 3D chromatin organization, DNA replication fork progression, and DNA double-strand break (DSB) repair. Recently, we discovered that cohesin SA1 and SA2 are DNA binding proteins. Given the recently discovered link between SA2 and RNA-mediated biological pathways, we investigated whether or not SA1 and SA2 directly bind to RNA using a combination of bulk biochemical assays and single-molecule techniques, including atomic force microscopy (AFM) and the DNA tightrope assay. We discovered that both SA1 and SA2 bind to various RNA containing substrates, including ssRNA, dsRNA, RNA:DNA hybrids, and R-loops. Importantly, both SA1 and SA2 localize to regions on dsDNA that contain RNA. We directly compared the SA1/SA2 binding and R-loops sites extracted from Chromatin Immunoprecipitation sequencing (ChIP-seq) and DNA-RNA Immunoprecipitation sequencing (DRIP-Seq) data sets, respectively. This analysis revealed that SA1 and SA2 binding sites overlap significantly with R-loops. The majority of R-loop-localized SA1 and SA2 are also sites where other subunits of the cohesin complex bind. These results provide a new direction for future investigation of the diverse biological functions of SA1 and SA2.}, number={10}, journal={NUCLEIC ACIDS RESEARCH}, publisher={Oxford University Press (OUP)}, author={Pan, Hai and Jin, Miao and Ghadiyaram, Ashwin and Kaur, Parminder and Miller, Henry E. and Ta, Hai Minh and Liu, Ming and Fan, Yanlin and Mahn, Chelsea and Gorthi, Aparna and et al.}, year={2020}, month={Jun}, pages={5639–5655} }
 @article{wu_yang_han_liu_hawari_du_peng_foster_chen_koschan_et al._2020, title={Role of Lithium Codoping in Enhancing the Scintillation Yield of Aluminate Garnets}, volume={13}, ISSN={["2331-7019"]}, DOI={10.1103/PhysRevApplied.13.064060}, abstractNote={The aim of this work is to clarify the scintillation-yield enhancement in $\mathrm{Lu}\mathrm{YAG}:\mathrm{Pr}$ scintillators obtained by $\mathrm{Li}$ codoping via integrated study of the valence state of activators, the preferential site occupancy of $\mathrm{Li}$ codopants, and defect structures from experimental and theoretical insights. With $\mathrm{Li}$ codoping, the light yield and energy resolution of $10\ifmmode\times\else\texttimes\fi{}10\ifmmode\times\else\texttimes\fi{}10\phantom{\rule{0.1em}{0ex}}{\mathrm{mm}}^{3}$ $\mathrm{Lu}\mathrm{YAG}:\mathrm{Pr}$ samples are improved from 15 600 to 24 800 photons/MeV, and 5.3 to 4.3% at 662 keV, respectively. The optical absorption spectra indicate that $\mathrm{Li}$ codoping does not induce conversion of stable ${\mathrm{Pr}}^{3+}$ to ${\mathrm{Pr}}^{4+}$ in $\mathrm{Lu}\mathrm{YAG}:\mathrm{Pr}$ single crystals. Based on the formation energies of substitutional and interstitial $\mathrm{Li}$ sites using density-functional-theory (DFT) calculations and the ${}^{7}\mathrm{Li}$ nuclear magnetic resonance results, it is shown that the $\mathrm{Li}$ ions prefer to dominantly occupy the fourfold coordinated interstitial sites and fourfold coordinated $\mathrm{Al}$ sites. The systematic analysis of thermoluminescence glow curves, positron annihilation lifetime spectroscopies, and defect formation energies derived from DFT calculations reveals that the concentration of isolated $\mathrm{Lu}$ and $\mathrm{Al}$ vacancies as dominant acceptor defects is reduced by $\mathrm{Li}$ codoping, whilst the shallow ${\mathrm{Li}}_{i}$ interstitial defects and the deep ${V}_{O}$ oxygen vacancies are introduced simultaneously. We propose that the lowering of hole trapping at defects resulting from $\mathrm{Li}$ codoping contributes to the scintillation-yield enhancement.}, number={6}, journal={PHYSICAL REVIEW APPLIED}, author={Wu, Yuntao and Yang, Ge and Han, Dan and Liu, Ming and Hawari, Ayman and Du, Mao-Hua and Peng, Jing and Foster, Camera and Chen, Shiyou and Koschan, Merry and et al.}, year={2020}, month={Jun} }
 @article{zhou_liu_williams_griffin_cress_rivas_rudy_polcawich_glaser_bassiri-gharb_et al._2018, title={Radiation-induced changes of vacancy-type defects in ferroelectric capacitors as revealed by Doppler broadening positron annihilation spectroscopy}, volume={124}, ISSN={["1089-7550"]}, DOI={10.1063/1.5045189}, abstractNote={Thin film ferroelectric capacitors of composition Pb(Zr0.52Ti0.48)O3 were exposed to Fe3+ radiation (1011 to 1013 ions/cm2), and the change in the defect structure was investigated by Doppler broadening positron annihilation spectroscopy and other characterization techniques. As the radiation fluence increases, a systematic drop of the S parameter of the positron annihilation photopeak is observed and attributed to an increase in the Zr- and Ti-site related vacancies relative to the Pb-sites. The results demonstrate that the radiation has a more significant influence on the Zr- and Ti-sites relative to the Pb-sites. It is also observed that the S parameter of the Mn-doped samples is higher than the undoped counterparts. Coupled with ferroelectricity measurements and X-ray diffraction, the results suggest that the Mn dopant modifies the initial structure of the material and leads to a different functional response.Thin film ferroelectric capacitors of composition Pb(Zr0.52Ti0.48)O3 were exposed to Fe3+ radiation (1011 to 1013 ions/cm2), and the change in the defect structure was investigated by Doppler broadening positron annihilation spectroscopy and other characterization techniques. As the radiation fluence increases, a systematic drop of the S parameter of the positron annihilation photopeak is observed and attributed to an increase in the Zr- and Ti-site related vacancies relative to the Pb-sites. The results demonstrate that the radiation has a more significant influence on the Zr- and Ti-sites relative to the Pb-sites. It is also observed that the S parameter of the Mn-doped samples is higher than the undoped counterparts. Coupled with ferroelectricity measurements and X-ray diffraction, the results suggest that the Mn dopant modifies the initial structure of the material and leads to a different functional response.}, number={24}, journal={JOURNAL OF APPLIED PHYSICS}, author={Zhou, Hanhan and Liu, Ming and Williams, Samuel C. and Griffin, Lee A. and Cress, Cory D. and Rivas, Manuel and Rudy, Ryan Q. and Polcawich, Ronald G. and Glaser, Evan R. and Bassiri-Gharb, Nazanin and et al.}, year={2018}, month={Dec} }
 @article{torstensen_liu_jin_deng_hawari_syverud_spontak_gregersen_2018, title={Swelling and Free-Volume Characteristics of TEMPO-Oxidized Cellulose Nanofibril Films}, volume={19}, ISSN={["1526-4602"]}, DOI={10.1021/acs.biomac.7b01814}, abstractNote={Cellulose nanofibrils (CNFs) are becoming increasingly ubiquitous in diverse technologies requiring sustainable nanoscale species to form or modify films. The objective of the present study is to investigate the swelling behavior and accompanying free volume of self-standing TEMPO-oxidized (TO) CNF films in the presence of water vapor. For this purpose, we have performed time-resolved swelling experiments on films, prepared according to different experimental protocols, at 90% relative humidity (RH) and ambient temperature. Corresponding free-volume characteristics are elucidated by positron annihilation lifetime spectroscopy (PALS) conducted at ambient temperature and several RH levels. Increasing the drying temperature of the films (from ambient to 50 °C) is observed to promote an increase in film density, which serves to reduce bulk swelling. These elevated drying temperatures likewise cause the free-volume pore size measured by PALS to decrease, while the corresponding total free-volume fraction remains nearly constant. Similarly, dispersion of TO-CNF into aqueous suspensions by ultrasonication prior to film formation increases both the total free-volume fraction and pore size but reduces the size of individual nanofibrils with little net change in bulk swelling. The swelling and concurrent free-volume measurements reported here generally reveal an increase in the free volume of TO-CNF films with increasing RH.}, number={3}, journal={BIOMACROMOLECULES}, author={Torstensen, Jonathan O. and Liu, Ming and Jin, Soo-Ah and Deng, Liyuan and Hawari, Ayman I. and Syverud, Kristin and Spontak, Richard J. and Gregersen, Oyvind W.}, year={2018}, month={Mar}, pages={1016–1025} }
 @article{goshima_forney-stevens_liu_qian_tyagi_cicerone_pikal_2016, title={Addition of Monovalent Electrolytes to Improve Storage Stability of Freeze-Dried Protein Formulations}, volume={105}, ISSN={["1520-6017"]}, DOI={10.1016/j.xphs.2015.10.004}, abstractNote={This study investigates the effect of low levels of electrolytes on storage stability in freeze-dried sucrose-based protein formulations. Both bovine serum albumin and recombinant human serum albumin were freeze dried with sucrose and alkali halides (LiCl, NaCl, KCl, RbCl, and CsCl) at selected low levels. All formulations were stored at 50°C and 65°C up to 2 months and then assayed for protein aggregation. The data demonstrate that low levels of LiCl and NaCl enhance stability. No obvious correlations with either protein secondary structure or global dynamics (structural relaxation time) were found. However, good correlations were found between stability and both free-volume hole size via positron annihilation lifetime spectroscopy (PALS) and fast dynamics by neutron scattering. Volume changes on mixing and the partial molal volume of salt were also studied in an effort to detect decreases in free volume. These data did not support the hypothesis that reduction in free volume was the primary mechanism for salt-induced stabilization. Finally, a positive effect of postlyophilization annealing on stability was demonstrated. In summary, we find that small amounts of LiCl and NaCl significantly stabilize these proteins, which is a result at variance with conventional formulation wisdom.}, number={2}, journal={JOURNAL OF PHARMACEUTICAL SCIENCES}, author={Goshima, Hiroshika and Forney-Stevens, Kelly M. and Liu, Ming and Qian, Ken K. and Tyagi, Madhusudan and Cicerone, Marcus T. and Pikal, Michael J.}, year={2016}, month={Feb}, pages={530–541} }
 @article{liu_zhang_datseris_huang_2014, title={Improving Finite State Impedance Control of Active-Transfemoral Prosthesis Using Dempster-Shafer Based State Transition Rules}, volume={76}, ISSN={0921-0296 1573-0409}, url={http://dx.doi.org/10.1007/S10846-013-9979-3}, DOI={10.1007/s10846-013-9979-3}, number={3-4}, journal={Journal of Intelligent & Robotic Systems}, publisher={Springer Science and Business Media LLC}, author={Liu, Ming and Zhang, Fan and Datseris, Philip and Huang, He}, year={2014}, month={Dec}, pages={461–474} }
 @article{chieng_cicerone_zhong_liu_pikal_2013, title={Characterization of dynamics in complex lyophilized formulations: II. Analysis of density variations in terms of glass dynamics and comparisons with global mobility, fast dynamics, and Positron Annihilation Lifetime Spectroscopy (PALS)}, volume={85}, ISSN={["1873-3441"]}, DOI={10.1016/j.ejpb.2013.03.036}, abstractNote={Amorphous HES/disaccharide (trehalose or sucrose) formulations, with and without added polyols (glycerol and sorbitol) and disaccharide formulations of human growth hormone (hGH), were prepared by freeze drying and characterized with particular interest in methodology for using high precision density measurements to evaluate free volume changes and a focus on comparisons between "free volume" changes obtained from analysis of density data, fast dynamics (local mobility), and PALS characterization of "free volume" hole size. Density measurements were performed using a helium gas pycnometer, and fast dynamics was characterized using incoherent neutron scattering spectrometer. Addition of sucrose and trehalose to hGH decreases free volume in the system with sucrose marginally more effective than trehalose, consistent with superior pharmaceutical stability of sucrose hGH formulations well below Tg relative to trehalose. We find that density data may be analyzed in terms of free volume changes by evaluation of volume changes on mixing and calculation of apparent specific volumes from the densities. Addition of sucrose to HES decreases free volume, but the effect of trehalose is not detectable above experimental error. Addition of sorbitol or glycerol to HES/trehalose base formulations appears to significantly decrease free volume, consistent with the positive impact of such additions on pharmaceutical stability (i.e., degradation) in the glassy state. Free volume changes, evaluated from density data, fast dynamics amplitude of local motion, and PALS hole size data generally are in qualitative agreement for the HES/disaccharide systems studied. All predict decreasing molecular mobility as disaccharides are added to HES. Global mobility as measured by enthalpy relaxation times, increases as disaccharides, particularly sucrose, are added to HES.}, number={2}, journal={EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS}, author={Chieng, Norman and Cicerone, Marcus T. and Zhong, Qin and Liu, Ming and Pikal, Michael J.}, year={2013}, month={Oct}, pages={197–206} }
 @article{dutta_feldblyum_gidley_imirzian_liu_matzger_vallery_wong-foy_2013, title={Evidence of Positronium Bloch States in Porous Crystals of Zn4O-Coordination Polymers}, volume={110}, ISSN={["1079-7114"]}, DOI={10.1103/physrevlett.110.197403}, abstractNote={Positronium (Ps) is shown to exist in a delocalized state in self-assembled metalorganic crystals that have large 1.3-1.5 nm cell sizes. Belonging to a class of materials with record high accessible specific surface areas, these highly porous crystals are the first to allow direct probing with simple annihilation lifetime techniques of the transport properties of long-lived triplet Ps in what is hypothesized to be a Bloch state. Delocalized Ps has unprecedented (high) Ps mobility driven primarily by weak phonon scattering with unusual and profound consequences on how Ps probes the lattice.}, number={19}, journal={PHYSICAL REVIEW LETTERS}, author={Dutta, Dhanadeep and Feldblyum, Jeremy I. and Gidley, David W. and Imirzian, James and Liu, Ming and Matzger, Adam J. and Vallery, Richard S. and Wong-Foy, Antek G.}, year={2013}, month={May} }
 @article{king_bielefeld_xu_lanford_matsuda_dauskardt_kim_hondongwa_olasov_daly_et al._2013, title={Influence of network bond percolation on the thermal, mechanical, electrical and optical properties of high and low-k a-SiC:H thin films}, volume={379}, ISSN={["1873-4812"]}, DOI={10.1016/j.jnoncrysol.2013.07.028}, abstractNote={As demand for lower power and higher performance nano-electronic products increases, the semiconductor industry must adopt insulating materials with progressively lower dielectric constants (i.e. low-k) in order to minimize capacitive related power losses in integrated circuits. However in addition to a lower dielectric constant, low-k materials typically exhibit many other reduced material properties that have limited the ability of the semiconductor industry to implement them. In this article, we demonstrate that the reduced material properties exhibited by low-k materials can be understood based on bond constraint and percolation theory. Using a-SiC:H as a case study material, we utilize nuclear reaction analysis, Rutherford backscattering, nuclear magnetic resonance and transmission Fourier transform infra-red spectroscopy measurements to determine the average coordination (〈r〉) for these materials. Correlations of 〈r〉 to Young's modulus, hardness, thermal conductivity, resistivity, refractive index, intrinsic stress, mass density and porosity show that an extremely wide range in material properties (in some cases several orders of magnitude) can be achieved through reducing 〈r〉 via the controlled incorporation of terminal SiHx and CHx groups. We also demonstrate that the critical point at 〈r〉 ≤ 2.4 predicted by constraint theory exists in this material system and places limitations on the range of properties that can be achieved for future low-k a-SiC:H materials.}, journal={JOURNAL OF NON-CRYSTALLINE SOLIDS}, author={King, Sean W. and Bielefeld, Jeff and Xu, Guanghai and Lanford, William A. and Matsuda, Yusuke and Dauskardt, Reinhold H. and Kim, Namjun and Hondongwa, Donald and Olasov, Lauren and Daly, Brian and et al.}, year={2013}, month={Nov}, pages={67–79} }
 @inproceedings{liu_moxom_hawari_gidley_2013, title={The intense slow positron beam facility at The PULSTAR reactor and applications in nano-materials study}, volume={1525}, booktitle={Application of accelerators in research and industry}, author={Liu, M. and Moxom, J. and Hawari, A. I. and Gidley, D. W.}, year={2013}, pages={455–459} }