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Predicting the effect of cooling rates and initial hydrogen concentrations on porosity formation in Al-Si castings

materials Genome engineering Advances 2024年第3期2卷 117-129页

作者： Qinghuai Hou Junsheng Wang Yisheng Miao Xingxing Li Xuelong Wu Zhongyao Li Guangyuan Tian Decai Kong Xiaoying Ma Haibo Qiao Wenbo Wang Yuling Lang School of Materials Science and Engineering Beijing Institute of TechnologyBeijingChina Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijingChina School of Mechanical Engineering Beijing Institute of TechnologyBeijingChina CITIC Dicastal Co. Ltd.QinhuangdaoHebei ProvinceChina

Al-Si alloys are widely used in automotive casting components while microporosity has always been a detrimental defect that leads to property *** this study,a coupled three-dimensional cellular automata(CA)model has been used to predict the hydrogen porosity as functions of cooling rate and initial hydrogen *** quantifying the pore characteristics,it has been found that the average equivalent pore diameter decreases from 40.43 to 23.98μm and the pore number density increases from 10.3 to 26.6 mm^(−3)as the cooling rate changes from 2.6 to 19.4℃/s at the initial hydrogen concentration of 0.25 mL/100 *** is also notable that the pore size increases as the initial hydrogen concentration changes from 0.15 to 0.25 mL/100 g while the pore number remains *** addition,the linear regression between secondary dendrite arm spacing and the equivalent pore diameter has been studied for the first time,matching well with *** work exhibits the application of CA model in future process optimization and robust condition design for advanced automotive parts made of Al-Si alloys.

关键词： Al-Si alloy cellular automata cooling rate microporosity secondary dendrite arm spacing solidification

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A Runaway Electron Avalanche Surrogate for Partially Ionized Plasmas

arXiv

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arXiv 2025年

作者： Arnaud, Jonathan S. McDevitt, Christopher J. Tang, Xian-Zhu Nuclear Engineering Program Department of Materials Science and Engineering University of Florida GainesvilleFL32611 United States Theoretical Division Los Alamos National Laboratory Los AlamosNM87545 United States

A physics-constrained deep learning surrogate that predicts the exponential "avalanche" growth rate of runaway electrons (REs) for a plasma containing partially ionized impurities is developed. Specifically, a physics-informed neural network (PINN) that learns the adjoint of the relativistic Fokker-Planck equation in steady-state is derived, enabling a rapid surrogate of the RE avalanche for a broad range of plasma parameters, motivating a path towards an ML-accelerated integrated description of a tokamak disruption. A steady-state power balance equation together with atomic physics data is embedded directly into the PINN, thus limiting the PINN to train across physically consistent temperatures and charge state distributions. This restricted training domain enables accurate predictions of the PINN while drastically reducing the computational cost of training the model. In addition, a novel closure for the relativistic electron population used when evaluating the secondary source of REs is developed that enables improved accuracy compared to a Rosenbluth-Putvinski source. The avalanche surrogate is verified against Monte Carlo simulations, where it is shown to accurately predict the RE avalanche growth rate across a broad range of plasma parameters encompassing distinct tokamak disruption scenarios. © 2025, CC BY.

关键词： Fokker Planck equation

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Nucleation effects of coccoliths in portland cement

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Matter 2025年

作者： Beatty, Danielle N. Srubar, Wil V. Materials Science and Engineering Program University of Colorado Boulder 4001 Discovery Drive UCB 027 BoulderCO80303 United States Department of Civil Environmental and Architectural Engineering University of Colorado Boulder 1111 Engineering Drive ECOT 441 UCB 428 BoulderCO80309 United States

This work explores the use of photosynthesized coccoliths (intricate CaCO3 particles) as a nucleation agent or cement replacement in portland cement paste. First, coccoliths were produced and harvested from the marine microalgae Emiliania huxleyi and the particle size, morphology, and mineralogy were characterized. Then, the nucleation effects of E. huxleyi coccoliths as seeding agent (0.5, 1, 3, or 5 wt % additions) and limestone filler (5 and 15 wt % cement replacements) were studied using isothermal conduction calorimetry and compressive strength testing. The results were compared with five commercially available CaCO3 sources used as nucleation agents and fillers. While the high surface area of coccoliths (12.22 m2/g) enhanced water demand, it also enhanced nucleation during cement hydration without accelerating hydration, leading to enhanced early-age strength without detriments to 28-day strength. Results highlight a potential carbon reduction strategy, namely employing photosynthesis as a method of mineral admixture production, for the cement and concrete industry. © 2025 Elsevier Inc.

关键词： Portland cement

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Searching for quantum nonthermodynamic phenomena

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Physical Review E 2025年第5期111卷 054108-054108页

作者： Yu Qiao Program of Materials Science and Engineering University of California–San Diego La Jolla California 92093 USA and Department of Structural Engineering University of California–San Diego La Jolla California 92093-0085 USA

Recent research on the fundamentals of statistical mechanics has led to an interesting discovery. With locally nonchaotic barriers, as Boltzmann's H theorem is inapplicable, there exist nontrivial nonthermodynamic systems that can produce useful work by absorbing heat from a single thermal reservoir without any other effect, thereby breaking the boundaries of the second law of thermodynamics. The previous analyses used classical mechanical models. In the current investigation, the study is extended to quantum mechanics. First, we reiterate that the Fermi-Dirac distribution and the Bose-Einstein distribution are compatible with the generalized Maxwell's relations, which demonstrates the general robustness of the framework of quantum statistical mechanics. Next, we analyze a set of simple-step scattering problems. When the system is in contact with a thermal reservoir, a bound state inherently follows the second law of thermodynamics, while a scattering state may not. The root cause is associated with the nonlocal nature of the wave function. It implies that the nonthermodynamic phenomena favor unquantized energy and localized wave packets, exhibiting a tendency to occur in “semiclassical” setups.

关键词： Statistical mechanics

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In-Situ Study of the Effect of Grain Boundary Angle on Plastic Deformation of Inconel 718 at High Temperature

SSRN

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SSRN 2023年

作者： Chen, Jutian Lu, Junxia Cheng, Xiaopeng Guo, Guanghao Zhang, Yuefei Sun, Chaoyang Zhang, Ze Faculty of Materials and Manufacturing Beijing University of Technology Beijing100124 China School of Materials Science and Engineering Zhejiang University Hangzhou310058 China School of Mechanical Engineering University of Science and Technology Beijing Beijing100083 China

The effect of the grain boundary (GB) angle on plastic deformation of Inconel 718 (IN718) alloy was investigated in this paper, using in-situ tensile experiment at 650 °C in combination with crystal plasticity finite element method (CPFEM). The results indicate that dislocations tend to accumulate at GBs to form stress concentration, but the degree of stress concentration does not necessarily increase with the increase of the GB angle. It is attributed to the slip transfer at the GBs, determined by the angle between the slip systems of the two adjacent grains. There is a significant uncertainty in the slip transfer for GB angles larger than 10°. However, the m'αβ(SFα+SFβ) criterion as a function of the GB angle has some statistical separation significance, and the slip transfer tends to be at GB angles less than 30° and m'αβ(SFα+SFβ)>0.78. This study deepens the understanding of IN718 microplastic deformation and provides a new strategy to study the deformation behavior of superalloys. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

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MODELING AND PARAMETERIZATION OF A PEM FUEL CELL STACK FOR A SYSTEM INTEGRATION INTO A METAL HYDRIDE BASED HYDROGEN STORAGE SYSTEM 23

MODELING AND PARAMETERIZATION OF A PEM FUEL CELL STACK FOR A...

引用

23rd World Hydrogen Energy Conference: Bridging Continents by H2, WHEC 2022

作者： Guarneros, Myriam Covarrubias Dreistadt, David von Colbe, José Bellosta Capurso, Giovanni Siegers, Marion Jepsen, Julian Puszkiel, Julián Klassen, Thomas Faculty of Mechanical Engineering Institute of Materials Helmut Schmidt University Holstenhofweg 85 Hamburg22043 Germany Institute of Materials Research Helmholtz-Zentrum HEREON Max-Planck-Straße 1 Geesthacht21502 Germany Environmental Engineering Department Faculty of Life Science Hamburg University of Applied Science Ulmenliet 20 Hamburg21033 Germany

ISBN: (纸本)9786250008430

Power systems using renewable energy sources have emerged as a sustainable solution for decarbonizing the energy sector. Implementing such systems requires integrating them with an efficient storage medium to improve their reliability and flexibility. This work explores the modeling and parameterization of a fuel cell system, with the purpose of coupling it with a metal hydride-based hydrogen storage reservoir. An electrical and thermal 0D simulation model for a 1.6 kW air-cooled proton exchange fuel cell stack is developed to investigate its performance, heat transfer and temperature development. The model validation and simulation are done by testing it with four different steady-state power demand scenarios. Experimental results show an efficient thermal coupling between the fuel cell stack and the metal-hydride system. Simulations and experimental results show an excellent agreement. The developed modeling approach is also appliccable to the design of different gas-to-power configurations and sizes, for the design of fuel cell-metal hydride storage systems. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.

关键词： Simulink

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In silico drug delivery modeling of a novel Everolimus Coated Balloon 46

In silico drug delivery modeling of a novel Everolimus Coate...

引用

46th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBC 2024

作者： Kotoulas, Grigorios G. Loukas, Vasileios S. Karanasiou, Georgia S. Sakellarios, Antonis I. Pezoulas, Vasileios C. Katsouras, Christos C. Michalis, Lambros K. Semertzioglou, Arsen Moulas, Anargyros Geris, Liesbet Fotiadis, Dimitrios I. University of Patras Laboratory of Biomechanics and Biomedical Engineering Department of Mechanical and Aeronautics Engineering Patras Greece University of Ioannina Medical School Dept. of Cardiology GR Ioannina Greece Rontis Corporation S.A Larisa Greece University of Thessaly General Department Larisa Greece University of Liège Ku Leuven Department of Biomechanics and Computational Tissue Engineering Belgium University of Ioannina Unit of Medical Technology and Intelligent Information Systems Dept. of Materials Science and Engineering Ioannina Greece Biomedical Research Institute Foundation for Research and Technology Hellas FORTH-BRI Ioannina Greece

ISBN: (纸本)9798350371499

This study examines the drug elution process of a novel Everolimus Coated Balloon (ECB) that features a novel polymer mixture consisting of cellulose derivatives and accelerators, and Everolimus as the pharmaceutical component, based on commercially available PTCA balloon-catheter system. In this analysis, we utilized in silico postdeployment results comprising three distinct datasets of healthy porcine arteries undergoing PTCA with (a) Sirolimus, (b) Low-dose Everolimus, and (c) High-dose Everolimus. We developed a computational model that consists of the drug release from the balloon surface and the drug transport through the porous arterial wall given advection and diffusion properties. The comparative results of the current study highlight that: (a) among the high and low-dose Everolimus Eluting Balloons, diffusivity is the governing property and as such, respective amount of drug is eluted and bound by the arterial wall - effectively rendering the high-dose balloon powerful in its delivery properties, and (b) based on the diffusivity of Everolimus and Sirolimus, the Everolimus Eluting Balloons exhibit superior performance with respect to total bound drug of the arterial *** Relevance - The approach described in this article is a step farther toward precision drug release from DCB prediction. Furthermore, our study's findings demonstrate that higher drug concentration in the coating leads to higher binding amounts;this information could be utilized to inform the creation of novel Drug Coated Balloon (DCB). © 2024 IEEE.

关键词： Balloons

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Unraveling the reaction mechanism of high reversible capacity CuP_(2)/C anode with native oxidation PO_(x) component for sodium-ion batteries

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Chinese Chemical Letters 2025年第1期36卷 574-578页

作者： Huixin Chen Chen Zhao Hongjun Yue Guiming Zhong Xiang Han Liang Yin Ding Chen State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China CAS key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China Laboratory of Advanced Spectro-electrochemistry and Li-ion Batteries Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Institute of Physics Chinese Academy of SciencesBeijing 100190China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi institutesChinese Academy of SciencesXiamen 361021China

Phosphorus-based anode is a promising anode for sodium-ion batteries(SIBs)due to its high specific capacity,however,suffers from poor electronic conductivity and unfavorable electrochemical *** metals such as copper(Cu)into phosphorus has been demonstrated to not only improve the electronic conductivity but also accommodate the volume change during cycling,yet the underline sodiation mechanism is not ***,take a copper phosphide and reduced graphene oxide(CuP_(2)/C)composite as an example,which delivers a high reversible capacity of>900 mAh/***,it is revealed that the native oxidation PO_(x)components of the CuP_(2)/C composite show higher electrochemical reversibility than the bulk Cu P_(2),based on a quantitative analysis of high-resolution solid-state^(31)P NMR,ex-situ XPS and synchrotron X-ray diffraction characterization *** sodiation products Na_(3)PO_(4) and Na_(4)P_(2)O_(7) derived from PO_(x) could react with Na-P alloys and regenerate to PO_(x) during charge process,which probably accounts for the high reversible capacity of the Cu P_(2)/C *** findings also illustrate that the phosphorus transforms into nanocrystalline Na_(3)P and Na_(x)P alloys,which laterally shows crystallization-amorphization evolution process during cycling.

关键词： CuP_(2)/C composite POx component Reaction mechanism Solid-state NMR Sodium-ion batteries

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Synergistic effect of interstitial carbon strategy and 2D-2D van der Waals heterojunctions in Ci-MoS2/g-C3N4 for enhanced photocatalytic hydrogen evolution

引用

International Journal of Hydrogen Energy 2025年 145卷 681-691页

作者： Zhao, Hang Zhang, Zhongyu Zhang, Yanhua Yin, Chaojie Li, Zeyang Zhou, Wenquan Ma, Mei Zhang, Dan He, Ping Wu, Jiang Zheng, Puyan Ling, Yang College of Energy and Mechanical Engineering Shanghai University of Electric Power Shanghai 200090 China School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China Jiangsu Tianjie Environmental Device Company Yancheng 224055 China Institute of Photochemistry and Photofunctional Materials University of Shanghai for Science and Technology Shanghai 200093 China

Affected by the interface dipole effect and van der Waals strain effect, Fermi level matching and interface coupling strength have become key challenges in studying the application of 2D/2D van der Waals heterojunctions in the field of photocatalytic hydrogen evolution (PHE). To address this issue, a novel two-dimensional material, interstitial carbon-doped van der Waals heterojunction (Ci-MS/CN), was developed in this work for the first time. By optimizing the comprehensive performance of the interaction between materials at the interface, the structure significantly improved the electron transfer path of the heterojunction. Under the condition of platinum-free catalyst, Ci-MS/CN showed excellent PHE performance, and the product formation rate reached 3237.6 μmol g⁻¹ h⁻¹ (visible light condition), which was 48 times that of the traditional system. This performance improvement was attributed to the introduction of atomic-level interstitial carbon on the MoS2 subsurface, which precisely controlled the band gap matching and interface charge distribution of the heterojunction, thereby significantly enhancing the photoresponse behavior and surface catalytic activity. This work offers new insights and guidance for the in-depth understanding and design of efficient two-dimensional heterojunctions, and lays a solid foundation for the development of platinum-free photocatalytic hydrogen production technology.

关键词： 2D/2d van der waals heterojunction Interstitial atom strategy Photocatalytic hydrogen evolution Split levels

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Modeling and optimization of machining parameters for minimizing surface roughness and tool wear during AISI 52100 steel dry turning

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materials Today: Proceedings 2022年 50卷 1164-1172页

作者： Uma Maheshwera Reddy Paturi Ankathi Yash Sai Teja Palakurthy N.S. Reddy Department of Mechanical Engineering CVR College of Engineering Hyderabad Telangana 501510 India School of Materials Science and Engineering Gyeongsang National University Jinju 52828 South Korea

AISI 52100 steel machining has drawn a greater interest in industrial and manufacturing applications due to its high strength, sublime hardness, and impressive wear resistance. Conventional cutting fluid-assisted machining is an objectionable option owing to its threat to the environment and operators. Dry machining or near dry machining is the primary choice to promote sustainable manufacturing. Multi-objective optimization is becoming an indispensable phase in choosing cutting conditions for desirable machinability characteristics. In the present work, a multi-objective optimization approach is utilized to model and optimize the surface roughness and tool flank wear during the dry cutting of AISI 52100 steel. To examine and quantify the relationship between process input and output parameters, a full factorial design, a response surface methodology (RSM), and a desirability function approach is adopted. The obtained optimum levels of the control factors are cutting speed at 119.734 m/min, feed rate at 0.1 mm/rev, and depth of cut at 0.4 mm; and the corresponding predicted surface roughness and tool wear are 2.967 µm and 0.052 mm, respectively. Model fitness and efficacy were judged through confirmation tests. A correlation coefficient (R 2 ) of 0.9921 for surface roughness and 0.9876 for tool wear indicates a significant agreement between model predictions and experimental results. Thus, the RSM model used in the work can minimize the expensive experimental trials of machining processes.

关键词： Multi-objective optimization Response surface methodology Dry machining AISI 52100 steel Tool wear Surface roughness

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