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Improving Co2 Adsorption Capacity and Co2/N2 Selectivity of Uio-66-Nh2 Via Defect engineering and Il-Encapsulation

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SSRN

SSRN 2023年

作者： Kang, Dong A. murphy, Christian Jeong, Hae-Kwon Artie McFerrin Department of Chemical Engineering Texas A&M University 3122 TAMU College StationTX77843-3122 United States Department of Materials Science and Engineering Texas A&M University 3122 TAMU College StationTX77843-3122 United States

metal-organic frameworks (mOFs) has gained great research interest for CO2 capture due to their porous structure, functionality, and versatility. UiO-66 and its derivatives have been of particular interest since they have exhibited superior stability in aqueous, acidic, and thermal conditions. Among the derivatives of UiO-66, UiO-66-NH2 has shown the highest CO22 uptake capacity compared to others due to its CO2-philic amine group. However, there are only a few reports on further improving performances of UiO-66-NH2 through either synthetic or post-synthetic methods. On the other hands, incorporation of CO2-philic ionic liquid (IL) into porous materials such as mOFs and zeolites has shown enhanced CO2 uptake and CO2/N2 adsorption selectivity. Here, we report defective UiO-66-NH2 and their IL-encapsulated counterparts by using hydrochloric acid as a defect modulator followed by post-synthetic IL-encapsulation. The defective UiO-66-NH2 showed enhanced CO2 uptake capacity compared to its non-defective counterpart because of improved microporous structure. It was found that there exists an optimum linker deficiency yielding the highest CO2 capture performance due to enhanced textural properties overcoming the negative effect of reduced CO2-philic amine groups. Furthermore, IL-encapsulated UiO-66-NH2 showed a slight improvement in CO2/N2 selectivity but exhibited a notable reduction in CO2 uptake capacity because of decreased textural properties. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

A Size-Dependent Ideal Solution model for Liquid-Solid Phase Equilibria Prediction in Aqueous Organic Solutions

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arXiv 2024年

作者： Alliston, Spencer P. Dames, Chris Powell-Palm, matthew J. Department of Mechanical Engineering University of California Berkeley BerkeleyCA94720 United States J. Mike Walker '66 Department of Mechanical Engineering Texas A&M University 400 Bizzell St College StationTX77840 United States Department of Materials Science and Engineering Texas A&M University 400 Bizzell St College StationTX77840 United States Department of Biomedical Engineering Texas A&M UNiversity 400 Bizzell St College StationTX77840 United States

Predictive synthesis of aqueous organic solutions with desired liquid-solid phase equilibria could drive progress in industrial chemistry, cryopreservation, and beyond, but is limited by the predictive power of current solution thermodynamics models. In particular, few analytical models enable accurate liquidus and eutectic prediction based only on bulk thermodynamic properties of the pure components, requiring instead either direct measurement or costly simulation of solution properties. In this work, we demonstrate that a simple modification to the canonical ideal solution theory accounting for the entopic effects of dissimilar molecule sizes can transform its predictive power, while offering new insight into the thermodynamic nature of aqueous organic solutions. Incorporating a Flory-style entropy of mixing term that includes both the mole and volume fractions of each component, we derive size-dependent equations for the ideal chemical potential and liquidus temperature, and use them to predict the binary phase diagrams of water and 10 organic solutes of varying sizes. We show that sizedependent prediction outperforms the ideal model in all cases, reducing average error in the predicted liquidus temperature by 59%, eutectic temperature by 45%, and eutectic composition by 43%, as compared to experimental data. Furthermore, by retaining the ideal assumption that the enthalpy of mixing is zero, we demonstrate that for aqueous organic solutions, much of the deviation from ideality that is typically attributed to molecular interactions may in fact be explained by simple entropic size effects. These results suggest an underappreciated dominance of mixing entropy in these solutions, and provide a simple approach to predicting their phase equilibria. © 2024, CC BY.

关键词： Entropy

Decoding the Hidden Dynamics of Super-Arrhenius Hydrogen Diffusion in multi-Principal Element Alloys via machine Learning

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arXiv 2024年

作者： Shuang, Fei Ji, Yucheng Wei, Zixiong Dong, Chaofang Gao, Wei Laurenti, Luca Dey, Poulumi Department of Materials Science and Engineering Faculty of Mechanical Engineering Delft University of Technology Mekelweg 2 Delft2628 CD Netherlands Beijing Advanced Innovation Center for Materials Genome Engineering National Materials Corrosion and Protection Data Center Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing100083 China J. Mike Walker'66 Department of Mechanical Engineering Texas A&M University College StationTX77843 United States Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States Faculty of Mechanical Engineering Delft University of Technology Mekelweg 2 Delft2628 CD Netherlands

Understanding atomic hydrogen (H) diffusion in multi-principal element alloys (mPEAs) is essential for advancing clean energy technologies such as H transport, storage, and nuclear fusion applications. However, the vast compositional space and the intricate chemical environments inherent in mPEAs pose significant obstacles. In this work, we address this challenge by developing a multifaceted machine learning framework that integrates machine-learning force field, neural network-driven kinetic monte Carlo, and machine-learning symbolic regression. This framework allows for accurate investigation of H diffusion across the entire compositional space of body-centered cubic (BCC) refractory moNbTaW alloys, achieving density functional theory accuracy. For the first time, we discover that H diffusion in mPEAs exhibits super-Arrhenius behavior, described by the Vogel-Fulcher-Tammann model, where the Vogel temperature correlates with the 5th percentile of H solution energy spectrum. We also derive robust analytical expressions that can be used to predict H diffusivity in general BCC mPEAs. Our findings further elucidate that chemical short-range order (SRO) generally does not impact H diffusion, except it enhances diffusion when "H-favoring" elements (notably Nb and Ta) are present in low concentrations. These findings not only enhance our understanding of H diffusion dynamics in general mPEAs but also guide the development of advanced mPEAs in H-related applications by manipulating element type, composition and SRO. Copyright © 2024, The Authors. All rights reserved.

关键词： Niobium alloys

Digital image correlation through surface patterning of skins to monitor knee motion

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Biotribology 2023年 35-36卷

作者： Coburn, Keeley Velhal, mrudul Goenezen, Sevan Liang, Hong J. Mike Walker ’66 Department of Mechanical Engineering Texas A&M University 77843-3123 TX United States Department of Materials Science and Engineering Texas A&M University 77840 TX United States

Digital Image Correlation (DIC) systems have been used to measure surface displacement fields by tracking a pattern applied to a surface. Offering many benefits in comparison to conventional strain-measurement devices, the use of DIC has been reported in the study of tissue biomechanics and performance of joints underneath. In this study, a new method was developed to apply a quality speckle pattern on the skin of knees. Temporary tattoo paper provided a safe, easy, and quick way for pattern application to the skin without hindering its natural behavior. A pattern was developed for analyzing the knee during a squatting motion in which the field of view, system set up, and curvature of the knee were contributing factors to the development. This research is designed to prove the feasibility of using tattoo papers as patent indicators for DIC measurement. The software was able to map the entire region of the knee and measure the displacement of each area independent of other parts, thus making it easy to identify twisting and bending of the joint. Experimental results indicated that it is an effective method to accurately analyze the motion of the knee without the need of sophisticated equipment. This methodology can be used to understand how strain affects the knee during action and thus will be useful for various sports-related activities such as training and injury management. © 2023 Elsevier Ltd

关键词： Biomechanics Knee or artificial joints Non-invasive characterization Surface patterning

COLLECTIVE ACTION AND ENTANGLEmENT OF mAGNETICALLY ACTIVE LIQUID CRYSTAL ELASTOmER RIBBONS

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arXiv 2024年

作者： Dana, A. Benson, C. Sivaperuman Kalairaj, m. Hellikson, K. George, S.m. Chimene, D.C. Gibson, J.A. Tasmim, S. Kohl, P.A. Li, Y. Abdelrahman, m.K. Patil, V.P. Ware, T.H. Benson, Christian Kalairaj, manivannan Sivaperuman Hellikson, Kayla Gibson, Jared A. Tasmim, Seelay Chimene, David C. George, Sasha m. Abdelrahman, mustafa K. Kohl, Phillip A. Li, Youli Patil, Vishal P. Department of Materials Science and Engineering Texas A&M University College StationTX77843 United States Department of Biomedical Engineering Texas A&M University College StationTX77843 United States Materials Research Laboratory University of California - Santa Barbara Santa BarbaraCA93106 United States Department of Mathematics University of California La Jolla San DiegoCA92093 United States

Interactions between active individuals in animal collectives lead to emergent responses that remain elusive in synthetic soft matter. Here, shape-morphing polymers are used to create bio-inspired transient solids that self-assemble with controlled mechanical properties and disassemble on demand. Dilute-suspensions of magnetic, heat-responsive liquid crystal elastomer ribbons mechanically interlock, inducing reversible aggregation. A mathematical model is developed that sheds light on the role of topological mechanisms in aggregation. Aggregation was favored for ribbons with moderate curvature at 25◦C above crosslinking temperature as compared to flat ribbons or higher curvature ribbons at higher temperatures. The ribbon suspensions reversibly transition between fluid- and solid-like states, exhibiting up to 6 orders-of-magnitude increase in the storage moduli of the entangled aggregates compared with the liquid dispersions. Controlled dissociation is induced by imparting kinetic energy to the individual ribbons at high magnetic field rotation speeds (> 200 RPm). Ribbon shape and the medium in which dissociation occurs were shown to govern disassembly. Imparting dynamic collective behaviors into synthetic systems may enable a range of potential applications from bio-inspired soft robotics to injectable biomaterials. Copyright © 2024, The Authors. All rights reserved.

关键词： Kinetic energy

modeling Extensive Defects in metals through Classical Potential-Guided Sampling and Automated Configuration Reconstruction

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arXiv 2024年

作者： Shuang, Fei Liu, Kai Ji, Yucheng Gao, Wei Laurenti, Luca Dey, Poulumi Department of Materials Science and Engineering Faculty of Mechanical Engineering Delft University of Technology Mekelweg 2 Delft2628 CD Netherlands Beijing Advanced Innovation Center for Materials Genome Engineering National Materials Corrosion and Protection Data Center Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing100083 China J. Mike Walker’66 Department of Mechanical Engineering Texas A&M University College StationTX77843 United States Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States Faculty of Mechanical Engineering Delft University of Technology Mekelweg 2 Delft2628 CD Netherlands

Extended defects such as dislocation networks and general grain boundaries are ubiquitous in metals, and accurately modeling these extensive defects is crucial for understanding their deformation mechanisms. Existing machine learning interatomic potentials (mLIPs) often fall short in adequately describing these defects, as their significant characteristic sizes exceed the computational limits of first-principles calculations. In this study, we address these challenges by establishing a comprehensive defect genome through empirical interatomic potential-guided sampling. To further enable accurate first-principles calculations on this defect genome, we have developed an automated configuration reconstruction technique. This method transforms defect atomic clusters into periodic configurations through precise atom insertion, utilizing Grand Canonical monte Carlo simulations. These strategies enable the development of highly accurate and transferable mLIPs for modeling extensive defects in metals. Using body-centered cubic tungsten as a model system, we develop an mLIP that reveals unique plastic mechanisms in simulations of nanoindentation. This framework not only improves the modeling accuracy of extensive defects in crystalline materials but also establishes a robust foundation for further advancement of mLIP development through the strategic use of defect genomes. Copyright © 2024, The Authors. All rights reserved.

关键词： Crystalline materials

A Discrete Dislocation Analysis of Size-Dependent Plasticity in Torsion

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SSRN

SSRN 2024年

作者： Needleman, Alan Cruzado, A. Ariza, m.P. Ortiz, michael Benzerga, Amine A. Department of Aerospace Engineering Texas A&M University College StationTX77843 United States Escuela Técnica Superior de Ingeniería Universidad de Sevilla Sevilla41092 Spain Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States Division of Engineering and Applied Science California Institute of Technology PasadenaCA91125 United States

A method for solving three dimensional discrete dislocation plasticity boundaryvalue problems using a monopole representation of the dislocations is presented. At each time step, the displacement, strain and stress fields in a finite body are obtained by superposition of infinite body dislocation fields and an image field that enforces the boundary conditions. The three dimensional infinite body fields are obtained by representing dislocations as being comprised of points, termed monopoles, that carry dislocation line and Burgers vector information. The image fields are obtained from a three dimensional linear elastic finite element calculation. The implementation of the coupling of the monopole representation with the finite element method, including the interaction of curved dislocations with free surfaces, is presented in some detail because it differs significantly from an implementation with a line based dislocation representation. Numerical convergence and the modeling of dislocation loop nucleation for large scale computations are investigated. The monopole discrete dislocation plasticity framework is used to investigate the effect of size and initial dislocation density on the torsion of wires with diameters varying over three orders of magnitude. Depending on the initial dislocation source density and the wire diameter, three regimes of torsion-twist response are obtained: (i) for wires with a sufficiently small diameter, plastic deformation is nucleation controlled and is strongly size dependent;(ii) for wires with larger diameters dislocation plasticity is dislocation interaction controlled, with the emergence of geometrically necessary dislocations and dislocation pile-ups playing a key role, and is strongly size dependent;and (iii) for wires with sufficiently large diameters plastic deformation becomes less heterogeneous and the dependence on size is greatly diminished. © 2024, The Authors. All rights reserved.

关键词： Finite element method

A discrete dislocation analysis of size-dependent plasticity in torsion

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arXiv 2024年

作者： Cruzado, Aitor Ariza, m.P. Needleman, A. Ortiz, m. Benzerga, A.A. Department of Aerospace Engineering Texas A&M University College StationTX77843 United States Escuela Técnica Superior de Ingeniería Universidad de Sevilla Sevilla41092 Spain Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States Division of Engineering and Applied Science California Institute of Technology PasadenaCA91125 United States

A method for solving three dimensional discrete dislocation plasticity boundary-value problems using a monopole representation of the dislocations is presented. At each time step, the displacement, strain and stress fields in a finite body are obtained by superposition of infinite body dislocation fields and an image field that enforces the boundary conditions. The three dimensional infinite body fields are obtained by representing dislocations as being comprised of points, termed monopoles, that carry dislocation line and Burgers vector information. The image fields are obtained from a three dimensional linear elastic finite element calculation. The implementation of the coupling of the monopole representation with the finite element method, including the interaction of curved dislocations with free surfaces, is presented in some detail because it differs significantly from an implementation with a line based dislocation representation. Numerical convergence and the modeling of dislocation loop nucleation for large scale computations are investigated. The monopole discrete dislocation plasticity framework is used to investigate the effect of size and initial dislocation density on the torsion of wires with diameters varying over three orders of magnitude. Depending on the initial dislocation source density and the wire diameter, three regimes of torsion-twist response are obtained: (i) for wires with a sufficiently small diameter, plastic deformation is nucleation controlled and is strongly size dependent;(ii) for wires with larger diameters dislocation plasticity is dislocation interaction controlled, with the emergence of geometrically necessary dislocations and dislocation pile-ups playing a key role, and is strongly size dependent;and (iii) for wires with sufficiently large diameters plastic deformation becomes less heterogeneous and the dependence on size is greatly diminished. © 2024, CC BY-NC-ND.

关键词： Finite element method

On the helium bubble swelling in nano-oxide dispersion-strengthened steels

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Journal of materials science & Technology 2022年第10期105卷 172-181页

作者： Vladimir Krsjak Tielong Shen Jarmila Degmova Stanislav Sojak Erik Korpas Pavol Noga Werner Egger Bingsheng Li Vladimir Slugen Frank A.Garner Slovak University of Technology Faculty of Electrical Engineering and Information TechnologyInstitute of Nuclear and Physical EngineeringIlkovicova 3Bratislava 81219Slovakia Chinese Academy of Sciences Institute of Modern PhysicsLanzhou 730000China Slovak University of Technology Faculty of Materials Science and TechnologyAdvanced Technologies Research InstituteJana Bottu 2781/25Trnava 91724Slovakia Universität der Bundeswehr München Institut für Angewandte Physik und Messtechnik LRT2Werner-Heisenberg-Weg 39Neubiberg85577Germany Southwest University of Science and Technology State Key Laboratory for Environment-friendly Energy MaterialsMianyangSichuan 621010China Texas A&M University Nuclear Engineering DepartmentCollege StationTX 77843USA Radiation Effects Consulting LLC Richland WA 99354USA

The development of structural materials resistant to harsh radiation environments requires an in-depth understanding of the early stage of the aging *** radiation environments with high transmutation helium production rates such as in fusion and spallation applications,even materials with otherwise acceptable radiation stability may suffer from radiation embrittlement related to helium bubble *** theoretical modeling of helium-assisted cavity nucleation in pure metals and simple alloys provides some useful guidelines at the atomic scale level,these,however,do not overlap with the size resolution of available experimental *** this study,we employed slow positron beam spectroscopy to characterize the nucleation and growth of nano-scale helium bubbles in martensitic steels strengthened by thermodynamically stable nano-oxide *** combination with transmission electron microscopy,we experimentally characterized the evolution of helium bubbles from small clusters of radiation-induced vacancies to large cavities well resolvable by *** radiation resistance of oxide-dispersion strengthened steels dominates only in the early stages of bubble evolution,where positron lifetime measurements provide a missing piece of the microstructural puzzle conventionally constructed by TEm.

关键词： Ion irradiation Bubble swelling Helium Positron annihilation spectroscopy Oxide dispersion strengthened steels