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Method of cells-based multiscale modeling of elastic properties of filament wound C/C-siC including free si and matrix porosity

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Journal of Materials science & Technology 2019年第12期35卷 2906-2918页

作者： evan J.Pineda Marek Fassin stefanie Reese Jaan-Willem simon NAsA Glenn Research Center 21000 Brookpark RoadMS 49/7ClevelandOH 44135United States Institute for Applied Mechanics RWTH Aachen UniversityMies-van-der-Rohe-Str.152074 AachenGermany

Three different multiscale models, based on the method of cells(generalized and high fidelity) micromechanics models were developed and used to predict the elastic properties of C/C-siC composites. In particular, the following multiscale modeling strategies were employed: Concurrent modeling of all phases using the generalized method of cells, synergistic(two-way coupling in space) multiscale modeling with the generalized method of cells, and hierarchical(one-way coupling in space) multiscale modeling with the high fidelity generalized method of cells. The three models are validated against data from a hierarchical multiscale finite element model in the literature for a repeating unit cell of C/***, the multiscale models are used in conjunction with classical lamination theory to predict the stiffness of C/C-siC plates manufactured via a wet filament winding and liquid silicon infiltration process recently developed by the German Aerospace Institute. Finally, un-reacted si(or free si) and porosity in the C matrix are included in the multiscale model, and the effect of these new phases on the stiffness and local stresses are considered.

关键词： Multiscale modeling C/C-siC Ceramic matrix composites

Optimization of Artificial Viscosity in Production Codes Based on Gaussian Regression surrogate Models

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Communications on Applied Mathematics and Computation 2024年第3期6卷 1521-1550页

作者： Vitaliy Gyrya evan Lieberman Mark Kenamond Mikhail shashkov Applied Mathematics and Plasma Physics Theoretical DivisionMail Stop B284Los Alamos National LaboratoryLos AlamosNM 87545USA Continuum Models and Numerical Methods Group X-Computational Physics DivisionMail Stop F644Los Alamos National LaboratoryLos AlamosNM 87545USA Lagrangian Codes Group X-Computational Physics DivisionMail Stop T086Los Alamos National LaboratoryLos AlamosNM 87545USA

To accurately model flows with shock waves using staggered-grid Lagrangian hydrodynamics, the artificial viscosity has to be introduced to convert kinetic energy into internal energy, thereby increasing the entropy across shocks. Determining the appropriate strength of the artificial viscosity is an art and strongly depends on the particular problem and experience of the researcher. The objective of this study is to pose the problem of finding the appropriate strength of the artificial viscosity as an optimization problem and solve this problem using machine learning (ML) tools, specifically using surrogate models based on Gaussian Process regression (GPR) and Bayesian analysis. We describe the optimization method and discuss various practical details of its implementation. The shock-containing problems for which we apply this method all have been implemented in the LANL code FLAG (Burton in Connectivity structures and differencing techniques for staggered-grid free-Lagrange hydrodynamics, Tech. Rep. UCRL-JC-110555, Lawrence Livermore National Laboratory, Livermore, CA, 1992, 1992, in Consistent finite-volume discretization of hydrodynamic conservation laws for unstructured grids, Tech. Rep. CRL-JC-118788, Lawrence Livermore National Laboratory, Livermore, CA, 1992, 1994, Multidimensional discretization of conservation laws for unstructured polyhedral grids, Tech. Rep. UCRL-JC-118306, Lawrence Livermore National Laboratory, Livermore, CA, 1992, 1994, in FLAG, a multi-dimensional, multiple mesh, adaptive free-Lagrange, hydrodynamics code. In: NECDC, 1992). First, we apply ML to find optimal values to isolated shock problems of different strengths. second, we apply ML to optimize the viscosity for a one-dimensional (1D) propagating detonation problem based on Zel’dovich-von Neumann-Doring (ZND) (Fickett and Davis in Detonation: theory and experiment. Dover books on physics. Dover Publications, Mineola, 2000) detonation theory using a reactive burn model. We compare re

关键词： Optimization Artificial viscosity Gaussian regression surrigate model

Yttrium-90 microsphere selective internal radiation therapy for liver metastases following systemic chemotherapy and surgical resection for metastatic adrenocortical carcinoma

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World Journal of Clinical Oncology 2018年第1期9卷 20-25页

作者： Mina s Makary Lawrence s Krishner evan J Wuthrick Mark P Bloomston Joshua D Dowell Division of Vascular and Interventional Radiology Department of Radiology the Ohio State University Comprehensive Cancer Center Division of Medical Oncology Department of Internal Medicine the Ohio State University Comprehensive Cancer Center Department of Radiation Oncology the Ohio State University Comprehensive Cancer Center Division of surgical Oncology Department of Surgery and James Cancer Hospital and Richard Solove Research Institute the Ohio State University Comprehensive Cancer Center

Adrenocortical carcinoma(ACC)is a rare malignancy with generally poor outcomes and limited treatment *** surgical resection can be curative for early local disease,most patients present with advanced ACC owing to nonspecific *** those patients,treatment options include systemic chemotherapy and locoregional therapies including radiofrequency ablation and transarterial *** present the first reported case of utilizing yttrium-90 microsphere selective internal radiation therapy(sIRT)in combination with first line EDP-M(Etoposide,Doxorubicin,Cisplatin,Mitotane)chemotherapy and debulking surgical primary tumor resection for treatment of metastatic *** complete radiologic response has been maintained after twelve months with resolution of clinical *** findings prompt the need for further consideration and studies to elucidate the role of sIRT in combination with systemic and surgical treatment for metastatic ACC.

关键词： Adrenocortical carcinoma Hepatic metastases Radioembolization Yttrium-90

Pulse Laser Deposition of HfO_(2)Nanoporous-Like structure,Physical Properties for Device Fabrication

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Journal of Renewable Materials 2022年第11期10卷 2819-2834页

作者： shams B.Ali sarmad Fawzi Hamza Alhasan evan T.salim Forat H.Alsultany Omar s.Dahham Laser and Optoelectronic Engineering Department University of TechnologyBaghdadIraq Applied science Department University of TechnologyBaghdadIraq Al-Mustaqbal University College Department of Medical PhysicsHillahIraq Center of Excellence Geopolymer and Green Technology Faculty of Engineering TechnologyUniversiti Malaysia PerlisPerlisMalaysia Department of Civil Engineering College of EngineeringCihan University-ErbilKurdistan RegionIraq

The pulsed laser deposition(PLD)technology was used to effectively create conductive nano and micro hafnium oxide with great purity and transparency for(HfO_(2))*** many optoelectronics devices and their applications,the presence of a high dielectric substance like a nano HfO2,between the metal contacts and the substrates was *** used the Pulsed Laser Deposition method to fabricate an Al/HfO_(2)/p-si schottky barrier diode where the nanostructured HfO2 films as an intermediate layer and varied substrate *** optical result reveals a high degree of transparency(93%).The optical bandgap of deposited HfO2 films was observed to vary between 4.9 and 5.3 eV,with a value of roughly 5.3 eV at the optimal preparation *** morphology of the surface shows a high homogeneous nano structure with the average values of the roughness about(0.3 nm).With regard to substrate temperature,the produced factor ideality for fabricated diode was determined to be lowering and the associated values of the barrier height rose based on *** regard to substrate temperature,the produced factor ideality for fabricated diode was determined to be lowering and the associated values of the barrier height rose based on I-V *** diode manufactured at 600℃,in particular,had a higher ideality factor value(n=3.2).

关键词： Pulse laser deposition nano films optoelectronics HfO_(2) optical device

Witten's D_4 Integrable Hierarchies Conjecture

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Chinese Annals of Mathematics,series B 2016年第2期37卷 175-192页

作者： Huijun FAN Amanda FRANCIs Tyler JARVIs evan MERRELL Yongbin RUAN school of Mathematical sciences Peking University Department of Mathematics Brigham Young University Department of Mathematics University of Michigan Ann Arbor the Yangtz Center of Mathematics at sichuan University

The authors prove that the total descendant potential functions of the theory of Fan-Jarvis-Ruan-Witten for D4 with symmetry group J and for D4T with symmetry group Gmax, respectively, are both tau-functions of the D4 Kac-Wakimoto/Drinfeld-sokolov hierarchy. This completes the proof, begun in the article by Fan-Jarvis-Ruan（2013）, of the Witten Integrable Hierarchies Conjecture for all simple（ADE） singularities.

关键词： Quantum cohomology Frobenius manifolds singularity theory Integrable hierarchies

An index for deformation controllability of small-volume materials

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science China(Technological sciences) 2014年第4期57卷 663-670页

作者： WANG ZhangJie sHAN ZhiWei LI Ju sUN Jun MA evan Center for Advancing Materials Performance from the Nanoscale CAMP-Nano) & Hysitron Applied Research Center in China (HARCC) State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Department of Nuclear science and Engineering and Department of Materials science and Engineering Massachusetts Institute of Technology Department of Materials science and Engineering Johns Hopkins University

Mechanical tests on small-volume materials show that in addition to the usual attributes of strength and ductility, the controlla- bility of deformation would be crucial for the purpose of precise plastic shaping. In our present work, a ＂mechanical controlla- bility index＂（MCI） has been proposed to assess the controllability of mechanical deformation quantitatively. The index allows quantitative evaluation of the relative fraction of the controllable plastic strain out of the total strain. MCI=0 means completely uncontrollable plastic deformation, MCI=∞ means perfectly controllable plastic shaping. The application of the index is demonstrated here by comparing two example cases： 0.273 to 0.429 for single crystal A1 nanopillars that exhibit obvious strain bursts, versus 3.17 to 4.2 for polycrystalline A1 nanopillars of similar size for which the stress-strain curve is smoother.

关键词： mechanical controllability index plastic deformation strain bursts nanomechanics

In-situ surface transformation of magnesium to protect against oxidation at elevated temperatures

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Journal of Materials science & Technology 2020年第9期44卷 48-53页

作者： Yuecun Wang Meng Li Yueqing Yang Xin’ai Zhao evan Ma Zhiwei shan Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)&Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an710049China Department of Materials science and Engineering Johns Hopkins UniversityBaltimore21218MDUSA

The native oxide thin scale on magnesium(Mg)surface appears continuous and crack-free,but cannot protect the Mg matrix from further oxidation,especially at elevated *** thermal oxidation process is witnessed in its entirety using a home-made in-situ heating device inside an environmental electron transmission *** proposed,and verified with real-time experimental evidence,that transforming the native oxide scale into a thin continuous surface layer with high vacancy formation energy(low vacancy concentration),for example MgCO3,can effectively protect Mg from high-temperature oxidation and raise the threshold oxidation temperature by at least two hundred degrees.

关键词： Magnesium Thermal oxidation In-situ E-TEM Carbonation Oxidation inhibition

The effect of surface electronic structures of Au/TiO_2 on sonophotochemical reactions

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Chinese Chemical Letters 2018年第6期29卷 783-786页

作者： Kun Qian evan Wenbo Zhao shuai He Wei David Wei Department of Chemistry and Center for Catalysis University of Florida Department of Chemical Physics University of Science and Technology of China

sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water（H2 O） reduction. surprisingly, no significant increase of the hydrogen（H2） production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.

关键词： sonophotocatalysis Localized surface plasmon resonance Electronic structure Water reduction Au/TiO2

Theoretical potential for low energy consumption phase change memory utilizing electrostatically-induced structural phase transitions in 2D materials

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npj Computational Materials 2018年第1期4卷 653-661页

作者： Daniel A.Rehn Yao Li Eric Pop evan J.Reed Department of Mechanical Engineering Stanford UniversityStanfordCA 94305USA Department of Applied Physics Stanford UniversityStanfordCA 94305USA Department of Electrical Engineering Stanford UniversityStanfordCA 94305USA Department of Materials science and Engineering Stanford UniversityStanfordCA 94305USA

structural phase-change materials are of great importance for applications in information storage *** driven structural phase transitions are employed in phase-change memory to achieve lower programming voltages and potentially lower energy consumption than mainstream nonvolatile memory ***,the waste heat generated by such thermal mechanisms is often not optimized,and could present a limiting factor to widespread *** potential for electrostatically driven structural phase transitions has recently been predicted and subsequently reported in some two-dimensional materials,providing an athermal mechanism to dynamically control properties of these materials in a nonvolatile fashion while achieving potentially lower energy *** this work,we employ DFT-based calculations to make theoretical comparisons of the energy required to drive electrostatically-induced and thermally-induced phase *** theoretical limits in monolayer MoTe2 and thin films of Ge_(2)sb_(2)Te_(5),we find that the energy consumption per unit volume of the electrostatically driven phase transition in monolayer MoTe2 at room temperature is 9% of the adiabatic lower limit of the thermally driven phase transition in Ge_(2)sb_(2)Te_(5).Furthermore,experimentally reported phase change energy consumption of Ge_(2)sb_(2)Te_(5) is 100–10,000 times larger than the adiabatic lower limit due to waste heat flow out of the material,leaving the possibility for energy consumption in monolayer MoTe2-based devices to be orders of magnitude smaller than Ge_(2)sb_(2)Te_(5)-based devices.

关键词： transitions phase structural