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A particle-resolved heat-particle-fluid coupling model by.DEM-IMB-LBM

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Journal of Rock.Mechanics and Geotechnical Engineering 2024年第6期16卷 2267-2281页

作者： Ming Xia jinlong Fu y.T.Feng Fengqiang Gong jin y. Hunan k.y.Laboratory.of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China Zienk.ewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil Engineering Southeast UniversityNanjing211189China Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently.encountered and also an active area of research in geotechnical *** this work.a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary.IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently.proposed Dirichlet-ty.e thermal boundary.condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant phy.ical variables to lattice ***,benchmark.tests,including a single-particle sedimentation and a two-particle drafting-k.ssing-tumbling(Dk.)simulation with heat transfer,are carried out to validate the accuracy.of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-ty.e thermal boundary Direct numerical simulation

Supposition of graphene stack. to estimate the contact resistance and conductivity.of nanocomposites

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 663-676页

作者： y.ZARE M.T.MUNIR G.J.WENG k.y.RHEE Biomaterials and Tissue Engineering Research Group Department of Interdisciplinary TechnologiesBreast Cancer Research CenterMotamed Cancer InstituteTehran ***Iran College of Engineering and Technology American University of the Middle EastEgaila 54200Kuwait Department of Mechanical and Aerospace Engineering Rutgers UniversityNew BrunswickNJ 08903U.S.A. Department of Mechanical Engineering(Bk.1 Four) College of EngineeringKyung Hee UniversityYongin 446701Republic of Korea

In this study.the effects of stack.d nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity.of samples are evaluated with developed equations superior to those previously.*** contact resistance and nanocomposite conductivity.are modeled by.several influencing factors,including stack.properties,interphase depth,tunneling size,and contact *** developed model's accuracy.is verified through numerous experimental *** further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity.are ***,the contact resistance is primarily.dependent on the poly.er tunnel resistivity.contact area,and tunneling *** dimensions of the graphene nanosheets significantly.influence the conductivity.which ranges from 0 S/m to90 S/*** increased number of nanosheets in stack. and a larger gap between them enhance the nanocomposite's ***,the thick.r interphase and smaller tunneling size can lead to higher sample conductivity.due to their optimistic effects on the percolation threshold and network.efficacy.

关键词： graphene poly.er composite stack.d nanosheet tunneling conductivity contact resistance interphase

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An MPI parallel DEM-IMB-LBM framework.for simulating fluid-solid interaction problems

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Journal of Rock.Mechanics and Geotechnical Engineering 2024年第6期16卷 2219-2231页

作者： Ming Xia Liuhong Deng Fengqiang Gong Tongming Qu y.T.Feng jin y. Hunan k.y.Laboratory.of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China School of Civil Engineering Southeast UniversityNanjing211189China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyHong KongChina Zienk.ewicz Centre for Computational Engineering Swansea UniversitySwanseaSA18ENUK Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

The high-resolution DEM-IMB-LBM model can accurately.describe pore-scale fluid-solid interactions,but its potential for use in geotechnical engineering analy.is has not been fully.unleashed due to its prohibitive computational *** overcome this limitation,a message passing interface(MPI)parallel DEM-IMB-LBM framework.is proposed aimed at enhancing computation *** framework.utilises a static domain decomposition scheme,with the entire computation domain being decomposed into multiple subdomains according to predefined processors.A detailed parallel strategy.is employ.d for both contact detection and hy.rody.amic force *** particular,a particle ID re-numbering scheme is proposed to handle particle transitions across sub-domain *** benchmark. are conducted to validate the accuracy.and overall performance of the proposed ***,the framework.is applied to simulate scenarios involving multi-particle sedimentation and submarine *** numerical examples effectively.demonstrate the robustness and applicability.of the MPI parallel DEM-IMB-LBM framework.

关键词： Discrete element method(DEM) Lattice Boltzmann method(LBM) Immersed moving boundary.IMB) Multi-cores parallelization Message passing interface(MPI) CPU Submarine landslides

Annotated survey.and perspectives on rail transport energy.sy.tem RAMS evaluation technology

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Green Energy.and Intelligent Transportation 2024年第3期3卷 75-90页

作者： Ruifeng Shi Lingzhi Zhang Feng Lin jin Ning Limin Jia k.ang y.Lee School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China China Institute of Energy.and Transportation Integrated Development Beijing 102206China State k.y.Lab of Rail Traffic Control&Safety Beijing Jiaotong UniversityBeijing 100044China Department of Electrical and Computer Engineering Baylor UniversityWacoTX 76798USA

The rail transit sy.tem play. a crucial role in modern *** the increasing demand for clean and green energy.in the transport sector,its energy.sy.tem is expected to achieve low-carbon and highly.efficient energy.utilization in rail ***,the gradual development of the rail transport energy.sy.tem has led to an increase in its complexity.and the rising difficulty.of sy.tem assessment has faced the limitations of traditional assessment ***,it is essential to develop effective assessment *** paper begins by.providing a sy.tematic review of the development status of Reliability.Availability.Maintainability.and Safety.RAMS)assessment and analy.ing the shortcomings of traditional RAMS assessment technology.in the context of rail transit energy.***,based on the four fundamental properties of RAMS,it summarizes the current state of k.y.assessment technologies in the field of rail ***,the paper delves into the challenges and potential solutions concerning the implementation of RAMS assessment technology.for rail transit energy.***,the paper offers an outlook.on the future development of RAMS assessment for rail transport energy.*** comprehensively.analy.ing these aspects,the paper aims to contribute valuable insights into optimizing the rail transit energy.sy.tem,promoting its sustainable and efficient operation in the context of clean and green energy.utilization.

关键词： Integration of energy.and transportation RAMS evaluation Rail transit energy.sy.tem

Shor's algorithm does not factor large integers in the presence of noise

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Science China(Information Sciences) 2024年第7期67卷 305-320页

作者： jin-y. CAI College of Letters and Science University of Wisconsin

We consider Shor's quantum factoring algorithm in the setting of noisy.quantum gates. Under a generic model of random noise for(controlled) rotation gates, we prove that the algorithm does not factor integers of the form pq when the noise exceeds a vanishingly.small level in terms of n—the number of bits of the integer to be factored, where p and q are from a well-defined set of primes of positive density. We further prove that with probability.1-o(1) over random prime pairs(p, q), Shor's factoring algorithm does not factor numbers of the form pq, with the same level of random noise present.

关键词： random noise Shor's algorithm rotation gates quantum computing prime factorization

LiDAR-based estimation of bounding box coordinates using Gaussian process regression and particle swarm optimization

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Biomimetic Intelligence & Robotics 2024年第1期4卷 24-35页

作者： Vinodha k. E.S.Gopi Tushar Agnibhoj Department of Electronics and Communication Engineering National Institute of Technology TiruchirappalliTamil Nadu620015India

Camera-based object track.ng sy.tems in a given closed environment lack.privacy.and *** this study.light detection and ranging(LiDAR)was applied to track.objects similar to the camera track.ng in a closed environment,guaranteeing privacy.and *** primary.objective was to demonstrate the efficacy.of the proposed technique through carefully.designed experiments conducted using two *** Scenario I,the study.illustrates the capability.of the proposed technique to detect the locations of multiple objects positioned on a flat surface,achieved by.analy.ing LiDAR data collected from several locations within the closed *** II demonstrates the effectiveness of the proposed technique in detecting multiple objects using LiDAR data obtained from a single,fixed ***-time experiments are conducted with human subjects navigating predefined *** individuals move within an environment,while LiDAR,fixed at the center,dy.amically.track. and identifies their locations at multiple *** demonstrate that a single,strategically.positioned LiDAR can adeptly.detect objects in motion around ***,this study.provides a comparison of various regression techniques for predicting bounding box *** process regression(GPR),combined with particle swarm optimization(PSO)for prediction,achieves the lowest prediction mean square error of all the regression techniques examined at *** tuning of GPR using PSO significantly.minimizes the regression *** of the experiment pave the way.for its extension to various real-time applications such as crowd management in malls,surveillance sy.tems,and various Internet of Things scenarios.

关键词： LiDAR Data acquisition Bounding box Gaussian process regression Particle swarm optimization(PSO)

Hard y.t tough and self-lubricating(CuNiTiNbCr)C_(x) high-entropy.nanocomposite films:Effects of carbon content on structure and properties

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Journal of Materials Science & Technology 2024年第6期173卷 20-30页

作者： y.T.Li X.M.Chen X.k.Zeng M.Liu X.Jiang y.X.Leng k.y.Laboratory.of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China k.y.Laboratory.of Noise and Vibration Research Institute of AcousticsChinese Academy of SciencesBeijing 100190China State k.y.Laboratory.of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China School of Mechanical and Electrical Engineering Mianyang Teachers’CollegeMianyang 621000China

The single-phase high-entropy.alloy.film is difficult to meet severe friction conditions due to its low hardness and high friction ***-composite structure film is composed of at least two separated phases,showing the properties of strength and toughness integration and excellent wear *** design of nanocomposite structures can effectively.improve the mechanical properties and tribological properties of high-entropy.alloy.*** this study.the(CuNiTiNbCr)C_(x) nanocomposite high-entropy.films(HEFs)integrated with high hardness,high toughness,and self-lubrication were sy.thesized by.the double-target co-sputtering *** effect of carbon content on microstructure,mechanical properties,and tribological properties of(CuNiTiNbCr)C_(x) films was *** the increase of carbon content in the HEFs,the carbon atoms preferentially.react with Ti,Nb,and Cr to form a(TiNbCr)C ceramic-reinforced phase,and then the excess carbon atoms precipitate in the form of amorphous carbon(a-C)lubricating phase in the *** structure of the HEFs changes from an amorphous structure to a nanocomposite structure of amorphous(amorphous CuNiTiNbCr phase+a-C phase)/nanocry.talline(TiN-bCr)C *** the carbon content is about 21.2 at.%,the carbide phase in the film reaches saturation and the hardness and modulus of the films are highest,which are 18 GPa and 228 GPa,*** HEFs with a carbon content of 44.0 at.%show the best toughness and tribological properties with a friction coefficient of 0.16 and a wear rate of 2.4×10^(-6) mm^(3)/(N m),which is mainly.attributed to the excellent resistance to fatigue crack.growth and the interfacial lubricating lay.r formed in the friction *** nanocomposite(CuNiTiNbCr)C_(x) HEFs show very.promising application prospect in the field of friction protection.

关键词： High-entropy.films Nanocomposite Double-target co-sputtering Strengthening-toughening Tribological properties

Semi-analy.ical Solutions for Wellbores with Graded Sk.n Zones in Poroelastic Media

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Acta Mechanica Solida Sinica 2024年第3期37卷 385-395页

作者： Zhiqiang Fan Zhihe jin School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China Department of Mechanical Engineering University of MaineOronoME04469USA

In analy.ing the complex interaction between the wellbore and the reservoir formation,the hy.romechanical properties of the region proximal to the wellbore,referred to as the“wellbore sk.n zone”,play.a pivotal role in determining flow dy.amics and the resulting formation *** models of the wellbore sk.n zone generally.assume a constant permeability.throughout,resulting in a sharp permeability.discontinuity.at the sk.n-reservoir *** paper introduces a model for a wellbore with a continuously.graded sk.n zone of finite thick.ess within a poroelastic *** solutions are derived using the Laplace transform method,addressing both positive and negative sk.n *** results are presented to illustrate the effects of graded permeability.sk.n zone thick.ess on pore pressures and stresses around a *** results highlight a distinct divergence in stress and pore pressure fields when comparing wellbores with negative sk.n zones to those with positive sk.n zones or no sk.n at all.

关键词： Poroelastic Graded permeability Analy.ical solution Wellbore Sk.n zone

Advanced Algorithm for Parameters Estimation of Negative Binomial Distribution with High Dimensional Sparse Group Structure

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Journal of Sy.tems Science & Complexity 2024年第5期37卷 2173-2195页

作者： LI Meiqi jin Baisuo School of Management University of Science and Technology of ChinaHefei 230000China

Negative binomial regression is a powerful technique for modeling count data,particularly.when dealing with ***,estimating the parameters for large-dimensional sparse models is challenging due to the complexity.of optimizing the mean and dispersion parameter of the negative binomial *** address this issue,the authors propose a novel approach that employ. two iterations of the majorize-minimize(MM)algorithm,one for estimating the dispersion parameter and the other for estimating the mean *** approaches improve the convergence speed and stability.of the *** authors also use group penalty.for variable selection,which enhances the accuracy.and efficiency.of the *** proposed method provides an explicit solution,simplifies the iteration process,and maintains good stability.while ensuring algorithm ***,the authors apply.the proposed algorithm to the zero-inflated model and demonstrate its promising predictive performance on specific data *** research has important implications for count data modeling and analy.is in various fields,such as data mining,machine learning,and bioinformatics.

关键词： Group structure majorize-minimize(MM) negative binomial

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