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GPU accelerated MFiX-DEM simulations of granular and multiphase flows

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Particuology 2022年第3期20卷 14-24页

作者： Liqiang Lu National Energy Technology Laboratory MorgantownWV 26507United States leidos research support team MorgantownWV 26506United States

In this research,a Graphical Processing Unit(GPU)accelerated Discrete Element Method(DEM)code was developed and coupled with the Computational Fluid Dynamic(CFD)software MFiX to simulate granular and multiphase flows with heat transfers and chemical *** Fortran-based CFD solver was coupled with the CUDA/C++based DEM solver through inter-process *** speedup to the CPU version of MFiX-DEM is about 130-243 folds in the simulation of particle *** fluidized bed simulations,the DEM computation time is reduced from 91%to 17%with a speedup of 78 *** simulation of Geldart A particle fluidization revealed a similar level of importance of both fluid and particle *** filtered drag derived from the two-fluid model is suitable for Euler-Lagrangian simulations with both fluid and particle *** overcorrects the influence of sub-grid structures if used for simulations with only fluid coarse-graining.

关键词： GPU MFIX DEM Drag Fluidization

Phase-field framework with constraints and its applications to ductile fracture in polycrystals and fatigue

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npj Computational Materials 2022年第1期8卷 149-163页

作者： Fei Xue Tian-Le Cheng Yinkai Lei You-Hai Wen U.S.DOE National Energy Technology Laboratory AlbanyOR 97321USA leidos research support team AlbanyOR 97321USA

Modeling of ductile fracture in polycrystalline structures is challenging,since it requires integrated modeling of cracks,crystal plasticity,and *** we extend the typical phase-field framework to the situations with constraints on the order parameters,and formulate two types of phase-field models on ductile *** Type-Ⅰ model incorporates three sets of order parameters,which describe the distributions of cracks,plastic strain,and grains,*** plasticity is employed within grain interiors accommodated by J_(2)plasticity at grain *** applications of the Type-Ⅰ model to single crystals and bicrystals demonstrate the influences of grain orientations and grain boundaries on crack *** the Type-Ⅱ model,J_(2)plasticity is assumed for the whole system and grain structures are *** advantage of the efficiency of the fast Fourier transform,our Type-Ⅱ model is employed to study low cycle *** closure and striation-like patterning of plastic strain are observed in the *** growth rate is analyzed as a function of the J-integral,and the simulated fatigue life as a function of plastic strain agrees with the Coffin–Manson relation without a priori assumption.

关键词： ductile fatigue grain

Preliminary study on the influence of in situ filter size in CFD-DEM transfer kernel

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Particuology 2020年第4期18卷 205-209页

作者： William D.Fullmer Jordan Musser National Energy Technology Laboratory MorgantownWV26507USA leidos research support team MorgantownWV26507USA

An unknown in coupled Eulerian-Lagrangian models for particle flow,such as CFD-DEM,which has received fairly little attention in the literature to date is the size of the filter width in the transfer *** work provides a preliminary glimpse at how this parameter can influence the solution in cold-flow,unbounded *** to previously published direct numerical simulation data is used to suggest an appropriate range for this parameter.

关键词： CFD-DEM High-resolution Lagrangian-Eulerian kernel

Polysiloxane coatings on microspheres based on Multiphase Flow with Interface Exchange-Discrete Element Modelling

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Particuology 2022年第10期20卷 88-99页

作者： Sanjay Kumar Devendhar Singh Jean-FranCois Dietiker Kathy Lu Department of Materials Science and Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVirginia 24061USA National Energy Technology Laboratory PittsburghPA 15236USA leidos research support team PittsburghPA 15236-0940USA

Polysiloxane coatings on yttria stabilized zirconia(YSZ)microspheres of 500μm were simulated in a spout fluidized bed coater using Multiphase Flow with Interface Exchange-Discrete Element Modelling(MFiX-DEM).Two different coater configurations were developed to study the influence of gas velocity and its distribution on particle *** presence of the Wurster tube not only enhances the dis-tribution but also increases the overall residence time of the *** were also carried out with different Wurster tube positions(normal,10%and 20%lowered from its initial position).Among these,20%lowered Wurster tube position demonstrated the most effective coating *** effects of gas inlet pressure on the average gas velocity and the distribution of particles were *** than 97%of the particles can be *** derived results,including average gas velocity,particle retention percentage,and distribution of particles with gas velocity,are being used to guide the experimental work in obtaining defect-free coatings for YSZ microspheres.

关键词： Spouted bed Wurster tube Coating Yttria stabilized zirconia(YSZ) MFiX

Machine-learning informed prediction of high-entropy solid solution formation:Beyond the Hume-Rothery rules

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npj Computational Materials 2020年第1期6卷 1288-1295页

作者： Zongrui Pei Junqi Yin Jeffrey A.Hawk David E.Alman Michael C.Gao National Energy Technology Laboratory AlbanyOR 97321USA ORISE 100 ORAU WayOak RidgeTN 37830USA Oak Ridge National Laboratory Oak RidgeTN 37831USA leidos research support team AlbanyOR 97321USA

The empirical rules for the prediction of solid solution formation proposed so far in the literature usually have very compromised *** rules with seemingly good predictability were,however,tested using small data *** on an unprecedented large dataset containing 1252 multicomponent alloys,machine-learning methods showed that the formation of solid solutions can be very accurately predicted(93%).The machine-learning results help identify the most important features,such as molar volume,bulk modulus,and melting temperature.

关键词： temperature prediction alloys

Statistics of the NiCoCr medium-entropy alloy:Novel aspects of an old puzzle

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npj Computational Materials 2020年第1期6卷 610-615页

作者： Zongrui Pei Rui Li Michael C.Gao G.Malcolm Stocks Oak Ridge National Laboratory Oak RidgeTN 37831USA University of Tennessee KnoxvilleTN 37996USA National Energy Technology Laboratory AlbanyOR 97321USA leidos research support team 626 Cochrans Mill RoadP.O.Box 10940PittsburghPA 15236USA

We study the K-state phenomenon in the NiCoCr medium-entropy alloy using first-principles techniques jointly with the efficient Wang–Landau Monte Carlo and simulated annealing *** theoretical results successfully explain the existence of the peak around 940 K in the experimental specific heat curve that characterizes the K-state phenomenon and give a fine picture of its atomic *** peak is caused by the maximum change of the local configurations characterized by the short-range-order(SRO)parameters at that temperature.

关键词： alloy temperature entropy

Development and validation of SuperDEM for non-spherical particulate systems using a superquadric particle method

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Particuology 2022年第2期20卷 74-90页

作者： Xi Gao Jia Yu Ricardo J.F.Portal Jean-François Dietiker Mehrdad Shahnam William A.Rogers National Energy Technology Laboratory MorgantownWV 26506USA leidos research support team MorgantownWV 26506USA Centro de Investigação em Modelação e Otimização de Sistemas Multifuncionais Instituto Superior de Engenharia de LisboaPolytechnic Institute of Lisbon1959-007 LisboaPortugal Instituto de Engenharia Mecânica–Instituto Superior Técnico Universidade de Lisboa1049-001 LisboaPortugal

This article presents the development and validation of the Superquadric Discrete Element Method(SuperDEM)for non-spherical particle simulation using a superquadric particle method in open-source CFD suite MFiX.A superquadric particle-particle contact algorithm with accelerating and stabilizing strategy was developed.A superquadric particle-arbitrary wall contact algorithm was developed,which enables the simulation in complex *** solver was validated by comparing with experimental data generated in this study or available in the *** include cylinder contacting with a wall,static packing of M&M chocolate candies in a cylindrical container,static packing of cylinders in a cylindrical container,dynamic angle of repose of cylinders in a rotating drum,and discharging of chocolate candies from a ***,MPI parallelization of the solver was implemented and the parallel performance of the solver using MPI was assessed through large-scale simulations of 1 million,10 million,and 100 million particles on up to 6800 cores,which demonstrates that the SuperDEM solver has great potential for industrial-scale systems simulation.

关键词： DEM Particle Non-spherical Superquadric Parallelization MFiX

Analyzing Sequential Patterns in Retail Databases

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Journal of Computer Science & Technology 2007年第2期22卷 287-296页

作者： Unil Yun Electronics and Telecommunications research Institute Telematics & USN Research Division LBS/Telematics Convergence Research Team 161 Gajeong-dong Yuseong-gu Daejeon 305-700 Korea

Finding correlated sequential patterns in large sequence databases is one of the essential tasks in data mining since a huge number of sequential patterns are usually mined, but it is hard to find sequential patterns with the correlation. According to the requirement of real applications, the needed data analysis should be different. In previous mining approaches, after mining the sequential patterns, sequential patterns with the weak affinity are found even with a high minimum support. In this paper, a new framework is suggested for mining weighted support affinity patterns in which an objective measure, sequential ws-confidence is developed to detect correlated sequential patterns with weighted support affinity patterns. To efficiently prune the weak affinity patterns, it is proved that ws-confidence measure satisfies the anti-monotone and cross weighted support properties which can be applied to eliminate sequential patterns with dissimilar weighted support levels. Based on the framework, a weighted support affinity pattern mining algorithm （WSMiner） is suggested. The performance study shows that WSMiner is efficient and scalable for mining weighted support affinity patterns.

关键词： data mining sequential pattern mining sequential ws-confidence weighted support affinity

Wavefront control of subcycle vortex pulses via carrier-envelope-phase tailoring

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Light(Science & Applications) 2023年第12期12卷 2711-2722页

作者： Yu-Chieh Lin Katsumi Midorikawa Yasuo Nabekawa Attosecond Science research team RIKEN Center for Advanced Photonics2-1 HirosawaWakoSaitama 351-0198Japan

The carrier-envelope phase(CEP)of an ultrashort laser pulse is becoming more crucial to specify the temporal characteristic of the pulse's electric field when the pulse duration becomes shorter and attains the subcycle regime;here,the pulse duration of the intensity envelope is shorter than one cycle period of the carrier field *** this subcycle pulse involves a structured wavefront as is contained in an optical vortex(OV)pulse,the CEP has an impact on not only the temporal but also the spatial characteristics owing to the spatiotemporal coupling in the structured optical ***,the direct observation of the spatial effect of the CEP control has not yet been *** this study,we report on the measurement and control of the spatial wavefront of a subcycle OV pulse by adjusting the *** generate subcycle OV pulses,an optical parametric amplifier delivering subcycle Gaussian pulses and a Sagnac interferometer as a mode converter were integrated and provided an adequate spectral *** pulse duration of the generated OV pulse was 4.7 fs at a carrier wavelength of 1.54μ*** confirm the wavefront control with the alteration of the CEP,we developed a novel f-2f interferometer that exhibited spiral fringes originating from the spatial interference between the subcycle OV pulse and the second harmonic of the subcycle Gaussian pulse producing a parabolic wavefront as a reference;this resulted in the successful observation of the rotation of spiral interference fringes during CEP manipulation.

关键词： interferometer amplifier cycle