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High-throughput reaction engineering to assess the oxidation stability of mAX phases

npj Computational materials 2021年第1期7卷 20-32页

作者： D.Sauceda P.Singh A.R.Falkowski Y.Chen T.Doung G.Vazquez m.Radovic R.Arroyave Department of Materials Science & Engineering Texas A&M UniversityCollege StationTX 77843USA Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA Ames Laboratory US Department of EnergyIowa State UniversityAmesIA50011USA

The resistance to oxidizing environments exhibited by some mn+1AXn(mAX)phases stems from the formation of stable and protective oxide layers at high operating *** mAX phases are hexagonally arranged layered nitrides or carbides with general formula m_(n+1)AX_(n),n=1,2,3,where m is early transition elements,A is A block elements,and X is C/*** attempts to model and assess oxide phase stability in these systems has been limited in scope due to higher computational *** address the issue,we developed a machine-learning driven high-throughput framework for the fast assessment of phase stability and oxygen reactivity of 211 chemistry mAX phase m_(2)*** proposed scheme combines a sure independence screening sparsifying operator-based machine-learning model in combination with grand-canonical linear programming to assess temperaturedependent Gibbs free energies,reaction products,and elemental chemical activity during the oxidation of mAX *** thermodynamic stability,and chemical activity of constituent elements of Ti_(2)AlC with respect to oxygen were fully assessed to understand the high-temperature oxidation *** predictions are in good agreement with oxidation experiments performed on Ti_(2)*** were also able to explain the metastability of Ti_(2)SiC,which could not be synthesized experimentally due to higher stability of competing *** generality of the proposed approach,we discuss the oxidation mechanism of Cr_(2)*** insights of oxidation behavior will enable more efficient design and accelerated discovery of mAX phases with maintained performance in oxidizing environments at high temperatures。

关键词： stability mAX maintained

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Towards Scalable Automated Grading: Leveraging Large Language models for Conceptual Question Evaluation in engineering 1

Towards Scalable Automated Grading: Leveraging Large Languag...

引用

1st Workshop on Large Foundation models for Educational Assessment

作者： Gao, Rujun Guo, Xiaosu Li, Xiaodi Narayanan, Arun Balajiee Lekshmi Thomas, Naveen Srinivasa, Arun R. J. Mike Walker’66 Department of Mechanical Engineering Texas A&M University United States Computer Science Department University of Texas Dallas United States Intelligent Systems Program University of Pittsburgh United States Department of Artificial Intelligence and Informatics Mayo Clinic United States

This study explores the feasibility of using large language models (LLms), specifically GPT-4o (ChatGPT), for automated grading of conceptual questions in an undergraduate mechanical engineering course. We compared the grading performance of GPT-4o with that of human teaching assistants (TAs) on ten quiz problems from the mEEN 361 course at texas a&m university, each answered by approximately 225 students. Both the LLm and TAs followed the same instructor-provided rubric to ensure grading consistency. We evaluated performance using Spearman’s rank correlation coefficient and Root mean Square Error (RmSE) to assess the alignment between rankings and the accuracy of scores assigned by GPT-4o and TAs under zero- and few-shot grading settings. In the zero-shot setting, GPT-4o demonstrated a strong correlation with TA grading, with Spearman’s rank correlation coefficient exceeding 0.6 in seven out of ten datasets and reaching a high of 0.9387. Our analysis reveals that GPT-4o performs well when grading criteria are straightforward but struggles with nuanced answers, particularly those involving synonyms not present in the rubric. The model also tends to grade more stringently in ambiguous cases compared to human TAs. Overall, ChatGPT shows promise as a tool for grading conceptual questions, offering scalability and consistency. © 2024 R. Gao1, X. Guo2, X. Li4, A.B.L. Narayanan3, N. Thomas1 & A.R. Srinivasa1.

关键词： mean square error

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Data-Driven Study of Composition-Dependent Phase Compatibility in Niti Shape memory Alloys

SSRN

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SSRN 2024年

作者： Zadeh, Sina Hossein Cakirhan, Cem Khatamsaz, Danial Broucek, John Brown, Timothy D. Qian, Xiaoning Karaman, Ibrahim Arroyave, Raymundo Department of Materials Science & Engineering Texas A&M University United States Sandia National Laboratories United States Department of Electrical & Computer Engineering Texas A&M University United States

The martensitic transformation in NiTi-based Shape memory Alloys (SmAs) provides a basis for shape memory effect and superelasticity, thereby enabling applications requiring solid-state actuation and large recoverable shape changes upon mechanical load cycling. In order to tailor the transformation to a particular application, the compositional dependence of properties in NiTi-based SmAs, such as martensitic transformation temperatures and hysteresis, has been exploited. However, the compositional design space is large and complex, and experimental studies are expensive. In this work, we develop an interpretable piecewise linear regression model that predicts the λ2 parameter, a measure of compatibility between austenite and martensite phases, and an (indirect) factor that is well-correlated with martensitic transformation hysteresis, based on the chemical features derived from the alloy composition. The model is capable of predicting, for the first time, the type of martensitic transformation for a given alloy chemistry. The proposed model is validated by experimental data from the literature as well as in-house measurements. The results show that the model can effectively distinguish between B19 and B19' regions for any given composition in NiTi-based SmAs and accurately estimate the λ2 parameter. Our analysis also reveals that the weighted average of the quotient of the first ionization energy and the Voronoi coordination number is a key compositional characteristic that correlates with the λ2 parameter and thermodynamic responses, including the transformation hysteresis, martensite start temperature, and critical temperature. The work herein demonstrates the potential of data-driven methodologies for understanding and designing NiTi-based SmAs with desired transformation characteristics. © 2024, The Authors. All rights reserved.

关键词： martensitic transformations

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Data-driven study of composition-dependent phase compatibility in NiTi shape memory alloys

arXiv

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arXiv 2024年

The martensitic transformation in NiTi-based Shape memory Alloys (SmAs) provides a basis for shape memory effect and superelasticity, thereby enabling applications requiring solid-state actuation and large recoverable shape changes upon mechanical load cycling. In order to tailor the transformation to a particular application, the compositional dependence of properties in NiTi-based SmAs, such as martensitic transformation temperatures and hysteresis, has been exploited. However, the compositional design space is large and complex, and experimental studies are expensive. In this work, we develop an interpretable piecewise linear regression model that predicts the λ2 parameter, a measure of compatibility between austenite and martensite phases, and an (indirect) factor that is well-correlated with martensitic transformation hysteresis, based on the chemical features derived from the alloy composition. The model is capable of predicting, for the first time, the type of martensitic transformation for a given alloy chemistry. The proposed model is validated by experimental data from the literature as well as in-house measurements. The results show that the model can effectively distinguish between B19 and B19′ regions for any given composition in NiTi-based SmAs and accurately estimate the λ2 parameter. Our analysis also reveals that the weighted average of the quotient of the first ionization energy and the Voronoi coordination number is a key compositional characteristic that correlates with the λ2 parameter and thermodynamic responses, including the transformation hysteresis, martensite start temperature, and critical temperature. The work herein demonstrates the potential of data-driven methodologies for understanding and designing NiTi-based SmAs with desired transformation characteristics. © 2024, CC BY-NC-ND.

关键词： martensitic transformations

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Temperature- and Creep-Resistant Diels-Alder Salogels for Shape Stabilization of Salt Hydrate Phase Change materials

SSRN

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SSRN 2024年

作者： Sukhishvili, Svetlana A. Rajagopalan, Kartik Kumar Texas A&M University Department of Materials Science & Engineering College StationTX77843 United States

Reversible shape stabilization of inorganic salt hydrate phase change materials (PCms) above their melting point is required to overcome the leakage problem and end-of-life material removal in thermal management applications. However, previous strategies in designing PCm-stabilizing polymer networks, e.g. salogels, resulted in a limited range of temperature stability and thus could not be applied to PCms with widely ranging melting temperatures. In this work, we introduce a polymer salogel system that was able to retain PCms over a wide temperature range (up to 120 °C) while preserving temperature response of gelation above 120 °C. This system, based on the Diels-Alder (DA) reaction between furan-modified polyvinyl alcohol (PVA) and a bismaleimide crosslinker, also provided creep-resistant shape stabilization of two salt hydrate PCms lithium nitrate trihydrate (LiNO3.3H2O, LNH) and magnesium nitrate hexahydrate (mg(NO3)26H2O, mgNH) having widely different melting temperatures of 29 and 89 °C, respectively. Rheological studies comparing the DA salogels with boronate ester salogels showed that the stronger DA crosslinks conferred high elasticity and a high gel-to-sol transition temperature (Tgel > 120 °C) resulting in superior creep resistance (≥80% strain recovery at 95 °C) for DA salogels in LNH and mgNH at a low (5 wt%) polymer content. In contrast, the viscoelastic boronate ester salogels showed poor strain recovery after creep which reduced drastically with temperature. In addition, the DA salogels demonstrated high retention of thermal properties of a salt hydrate PCm over 50 melting/crystallization cycles. © 2024, The Authors. All rights reserved.

关键词： Gelation

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Polarization-dependent optical engineering of ferroelectric domains

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ChemPhysmater 2023年第4期2卷 346-350页

作者： Shan Liu Yan Sheng Wieslaw Krolikowski Department of Quantum Science and Technology Research School of PhysicsAustralian National UniversityCanberra 2601Australia Department of Electronic Materials Engineering Research School of PhysicsAustralian National UniversityCanberra 2601Australia Laboratory of Infrared Materials and Devices Research Institute of Advanced TechnologiesNingbo UniversityNingbo 315211China Science Program Texas A&M University at QatarDoha 23874Qatar

Ferroelectric domain engineering with infrared femtosecond laser pulses has been a powerful technique to achieve a spatially modulated second-order nonlinear coefficient in three ***,studies regarding the in-fluence of laser writing conditions on the light-induced ferroelectric domain inversion remain ***,an experimental study to reveal the role of laser polarization in light-induced domain inversions is *** dependence of the optical threshold and maximal writing depth of inverted domains on light polarization is ex-perimentally *** results are explained by considering the second-order nonlinear optical properties and birefringence-induced focus splitting in the *** findings are useful in fabricating high-quality and large-scale ferroelectric domain structures for applications in optics,electronics,and quantum technologies.

关键词： Nonlinear photonic crystals Ferroelectric domain engineering Quasi-phase matching Harmonic generation

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A Perspective on Plasticity, Dissipation and the 2nd Law of Thermodynamics

arXiv

引用

arXiv 2024年

作者： Needleman, Alan Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States

The requirement of a non-negative dissipation rate for all possible deformation histories is generally imposed on plastic constitutive relations. This is a constraint analogous to the Coleman-Noll [1] postulate that the Clausius-Duhem inequality needs to be satisfied for all possible deformation histories. The physical basis for the Clausius-Duhem inequality is as a statistical limit for a large number of discrete events for a long time and is not a fundamental physical requirement for small systems for a short time. The relation between the requirement of a non-negative dissipation rate and the Clausius-Duhem inequality is considered. The consequences of imposing a non-negative dissipation rate for all possible deformation histories are illustrated for: (i) a single crystal plasticity framework that accounts for elastic lattice curvature changes as well as elastic lattice straining;and (ii) for discrete defect theories of plasticity, with attention specifically on discrete dislocation plasticity for crystalline solids and discrete shear transformation zone (STZ) plasticity for amorphous solids. Possible less restrictive conditions on the evolution of dissipation in plasticity formulations are considered as are implications for stability. The focus is on open questions and issues. © 2024, CC BY-NC-ND.

关键词： Single crystals

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Decoding Non-Linearity and Complexity: Deep Tabular Learning Approaches for materials science

arXiv

引用

arXiv 2024年

作者： Attari, Vahid Arroyave, Raymundo Department of Materials Science & Engineering Texas A&M University College StationTX77840 United States

materials data, especially those related to high-temperature properties, pose significant challenges for machine learning models due to extreme skewness, wide feature ranges, modality, and complex relationships. While traditional models like tree-based ensembles (e.g., XGBoost, LightGBm) are commonly used for tabular data, they often struggle to fully capture the subtle interactions inherent in materials science data. In this study, we leverage deep learning techniques based on encoder-decoder architectures and attention-based models to handle these complexities. Our results demonstrate that XGBoost achieves the best loss value and the fastest trial duration, but deep encoder-decoder learning like Disjunctive Normal Form architecture (DNF-nets) offer competitive performance in capturing non-linear relationships, especially for highly skewed data distributions. However, convergence rates and trial durations for deep model such as CNN is slower, indicating areas for further optimization. The models introduced in this study offer robust and hybrid solutions for enhancing predictive accuracy in complex materials datasets. © 2024, CC BY-NC-SA.

关键词： Creep resistance

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Non-Schmid Continuum Slip Crystal Plasticity with Implications For Dissipation Rate

SSRN

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SSRN 2024年

作者： Srivastava, Ankit Needleman, Alan Department of Materials Science & Engineering Texas A&M University College StationTX77843 United States

Nonuniform plane strain tensile deformation of single crystals with an elastic-viscoplastic continuum slip crystal constitutive relation and with the driving force for slip including a non-Schmid stress is analyzed. The planar crystals considered have two potentially active slip systems with the non-Schmid term on a system being the Schmid resolved shear stress on the other system. Finite deformation finite element calculations are carried out for a rectangular bar with a small geometric imperfection to trigger nonuniform deformation. The parameters characterizing the non-Schmid term, including itsmagnitude and the slip interval over which it acts, are varied. The effect of non-Schmid governed slip on the overall stress strain response and on the strain at which a rapid drop in overall stress occurs are investigated. The dependence of the strain at which this rapid drop occurs on the parameters characterizing the non-Schmid term is not necessarily monotonic. The dissipation rate associated with non-Schmid governed plasticity is calculated both pointwise and integrated over the bar. Stable calculations up to the rapid drop in overall stress can be carried out even with the dissipation rate being negative at one or more points in the bar over some strain range and, in some cases even when the integrated dissipation rate is negative. For a range of values of the magnitude of the non-Schmid term it is found that, although the pointwise dissipation rate negative at some points in the bar, the integrated value can remain non-negative. Implications for possible constitutive restrictions are briefly considered. © 2024, The Authors. All rights reserved.

关键词： Drops

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Hierarchically porous metal–organic frameworks:synthetic strategies and applications

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National science Review 2020年第11期7卷 1743-1758页

作者： Liang Feng Kun-Yu Wang Xiu-Liang Lv Tian-Hao Yan Hong-Cai Zhou Department of Chemistry Texas A&M UniversityCollege Station Department of Materials Science and Engineering Texas A&M UniversityCollege Station

Despite numerous advantages, applications of conventional microporous metal–organic frameworks (mOFs) are hampered by their limited pore sizes, such as in heterogeneous catalysis and guest delivery,which usually involve large molecules. Construction of hierarchically porous mOFs (HP-mOFs) is vital to achieve the controllable augmentation of mOF pore size to mesopores or even macropores, which can enhance the diffusion kinetics of guests and improve the storage capacity. This review article focuses on recent advances in the methodology of HP-mOF synthesis, covering preparation of HP-mOFs with intrinsic hierarchical pores, and modulated, templated and template-free synthetic strategies for *** key factors which affect the formation of HP-mOF architectures are summarized and discussed,followed by a brief review of their applications in heterogeneous catalysis and guest encapsulation. Overall,this review presents a roadmap that will guide the future design and development of HP-mOF materials with molecular precision and mesoscopic complexity.

关键词： metal–organic frameworks hierarchical design synthesis application

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