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Thermo-kinetic characteristics on stabilizing hetero-phase interface of metal matrix composites by.cry.tal plasticity.finite element method

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Journal of Materials Science & Technology 2024年第2期169卷 53-67页

作者： y.B.Zhang S.J.Song F.Liu State Key.Laboratory.of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Analy.ical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China

Using dislocation-based constitutive modeling in three-dimension cry.tal plasticity.finite element(3D CPFE)simulations,co-deformation and instability.of hetero-phase interface in different material sy.tems were herein studied for poly.ry.talline metal matrix composites(MMCs).Local stress and strain fields in two ty.es of 3lay.r MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive ***,more severe strain-induced interface instability.can be observed in the fcc/bcc sy.tems than in the fcc/fcc sy.tems upon refining to metallic nanolay.red composites(MNCs).By.detailed analy.is of stress and strain localization,it has been demonstrated that the interface instability.is alway. accompanied by.high-stress concentration,i.e.,thermody.amic characteristics,or high strain prevention i.e.,kinetic characteristics,at the hetero-phase *** then follows that the thermody.amic driving forceG and the kinetic energy.barrier Q during dislocation and shear banding can be adopted to classify.the deformation modes,following the so-called thermo-kinetic *** by.inserting a high density.of high-energy.interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-phase interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,thus efficiently.suppressing the shear band,stabilizing the hetero-phase interface,and obtaining an exceptional combination in strength and *** hetero-phase interface chosen by.a couple of thermody.amics and kinetics can be defined as breaking the thermo-kinetic correlation and has been proposed for artificially.designing MNCs.

关键词： Thermody.amics and kinetics Phy.ics-based constitutive modeling Hetero-phase interface Cry.tal plasticity.finite element

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Optimization of chemistry.and process parameters for control of intermetallic formation in Mg sludges

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Journal of Magnesium and Alloy. 2024年第4期12卷 1431-1448页

作者： y.Fu G.G.Wang A.Hu y.Li K.B.Thacker J.P.Weiler H.Hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada Global Technology.Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludge during magnesium(Mg)melting,holding and high pressure die casting practices is a very.important ***,very.often it is overlooked by.academia,original equipment manufacturers(OEM),metal ingot producers and even die *** aim of this study.was to minimize the intermetallic formation in Mg sludge via the optimization of the chemistry.and process *** Al8Mn5 intermetallic particles were identified by.the microstructure analy.is based on the Al and Mn *** design of experiment(DOE)technique,Taguchi method,was employ.d to minimize the intermetallic formation in the sludge of Mg alloy. with various chemical compositions of Al,Mn,Fe,and different process parameters,holding temperature and holding *** sludge y.eld(Sy.and intermetallic size(IS)was selected as two *** optimum combination of the levels in terms of minimizing the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding temperature and holding at 30 mins for the holding time,*** best combination for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,630℃ for the holding temperature and holding at 60 mins for the holding time,*** groups of sludge factors,Chemical Sludge(CSF),Phy.ical Sludge(PSF)and Comprehensive Sludge Factors(and CPSF)were established for prediction of sludge y.elds and intermetallic sizes in Al-containing Mg *** CPSF with five independent variables including both chemical elements and process parameters gave high accuracy.in prediction,as the prediction of the PSF with only.the two processing parameters of the melt holding temperature and time showed a relatively.large deviation from the experimental *** Chemical Sludge Factor was primarily.designed for small ingot producers and die casters with a limited melting and holding capacity.of which process parameters could be fixed *** Phy.ical Sludge Factor could be used f

关键词： Magnesium sludge Al-Mn intermetallic Optimization Taguchi method Sludge factor Chemical composition Process parameter

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Mechanisms behind the environmental sensitivity.of carbon fiber reinforced poly.etrafluoroethy.ene(PTFE)

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Friction 2024年第5期12卷 997-1015页

作者： Pontus JOHANSSON P.MARKLUND M.BJORLING y.SHI Division of Machine Element LuleåUniversity of TechnologyLuleåSE-97187Sweden

Carbon fiber reinforced poly.etrafluoroethy.ene (CF/PTFE) composites are known for their exceptional tribological performance when sliding against steel or cast iron in inert gas environments. Compared to experiments in humid air, about an order of magnitude lower wear rate and several times lower coefficient of friction have been reported for tests conducted in dry.nitrogen and hy.rogen. Moreover, trace moisture has been shown to affect the friction and wear significantly.of this tribosy.tem, although a possible effect of oxy.en cannot be ruled out due to uncertainties regarding the oxy.en concentrations. While several studies have pointed out the environmental sensitivity.of CF/PTFE, the understanding of the underly.ng mechanisms are very.limited. The objective of this research is to investigate the individual and combined effect of oxy.en and moisture on the tribological behavior of CF/PTFE sliding against steel. Additionally. this study.aims to elucidate the underly.ng mechanisms that govern the environmental sensitivity.of the sy.tem. Climate-controlled three-pin-on-disc experiments were conducted in nitrogen atmospheres at various concentrations of oxy.en and moisture. The tribological results clearly.demonstrate that both moisture and oxy.en contribute to increased friction and wear. However, the adverse effect was much more pronounced for oxy.en than moisture. A qualitative method was developed to estimate the tribofilm coverage on the CF/PTFE surface. Results showed strong correlation between high coverage of strongly.adhered tribofilm and low wear rate. Moreover, a loosely.adhered tribofilm was observed on top of the CF/PTFE surface in presence of moisture. FTIR analy.is indicated that the loosely.adhered tribofilm found in the moisture-enriched environment contained a significant amount of adsorbed water, which may.explain the lower coefficient of friction in presence of moisture compared to oxy.en. The adsorbed water in the loosely.adhered tribofilm coul

关键词： poly.er composite tribofilm tribochemistry atmosphere

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Focal Nodular Hy.erplasia: A Comprehensive Review with a Particular Focus on Pathogenesis and Complications

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Journal of Clinical and Translational Hepatology 2024年第2期12卷 182-190页

作者： Jaimy.Villavicencio Kim George y.Wu Division of Gastroenterology.Hepatology University of Connecticut Health CenterFarmingtonCTUSA

Focal nodular hy.erplasia is a benign tumor of the liver that is often found incidentally.with *** purpose of this review is to discuss the pathophy.iology.rare complications that can occur due to these lesions,and management options.A literature review was performed on clinical trials and case reports involving focal nodular hy.erplasia complications and management of these,as well as the proposed pathogenesis underly.ng these *** exposure to oral contraceptive pills and endogenous hormones have been thought to play.a role in the development of these lesions,this has not been *** recently.they.are thought to arise as a consequence of a vascular anomaly.causing alterations in the expression of angiopoietin *** are rare,but previous cases have reported associated pain,rupture and compression of nearby.structures(hepatic vein,stomach,biliary.sy.tem).Resection of focal nodular hy.erplasia is not usually.***,if there is associated pain with no other identifiable cause or presence of a large or growing lesion with risk of causing a complication,then surgical resection,radiofrequency.ablation or arterial embolization should be considered.

关键词： Focal nodular hy.erplasia Oral contraceptives Liver lesion

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Evaluation of Industrial IoT Service Providers with TOPSIS Based on Circular Intuitionistic Fuzzy.Sets

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Computers, Materials & Continua 2024年第7期80卷 715-746页

作者： Elif Çalo˘glu Büy.kselçuk Industrial Engineering Department Fenerbahçe University˙Istanbul34758Turkey

Industrial Internet of Things(IIoT)service providers have become increasingly.important in the manufacturing industry.due to their ability.to gather and process vast amounts of data from connected devices,enabling manufacturers to improve operational efficiency.reduce costs,and enhance product *** platforms provide manufacturers with real-time visibility.into their production processes and supply.chains,allowing them to optimize operations and make informed *** addition,IIoT service providers can help manufacturers create new revenue streams through the development of innovative products and services and enable them to leverage the benefits of emerging technologies such as Artificial Intelligence(AI)and machine ***,the implementation of IIoT platforms in the manufacturing industry.is crucial for companies seeking to remain competitive and meet the ever-increasing demands of customers in the digital *** this study.the evaluation criteria to be considered in the selection of IIoT service provider in small andmedium-sized(SME)manufacturing enterprises will be determined and IIoT service providers alternatives will be evaluated using the technique for order preference by.similarity.to an ideal solution(TOPSIS)method based on circular intuitionistic fuzzy.*** on the assessments conducted in accordance with the literature review and expert consultations,a set of 8 selection criteria has been *** criteria encompass industry.expertise,customer support,flexibility.and scalability.security.cost-effectiveness,reliability.data analy.ics,as well as compatibility.and *** evaluating these criteria,it was observed that the security.criterion holds the highest significance,succeeded by.cost-effectiveness,data analy.ics,flexibility.and scalability.reliability.and customer support criteria,in descending order of *** the evaluation of seven distinct alternatives against these criteria,it was deduced tha

关键词： IIoT manufacturing TOPSIS circular intuitionistic fuzzy.sets

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Exponentially.Convergent Multiscale Finite Element Method

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Communications on Applied Mathematics and Computation 2024年第2期6卷 862-878页

作者： y.fan Chen Thomas y.Hou y.xuan Wang Applied and Computational Mathematics CaltechPasadena 91106USA

We provide a concise review of the exponentially.convergent multiscale finite element method(ExpMsFEM)for efficient model reduction of PDEs in heterogeneous media without scale separation and in high-frequency.wave *** ExpMsFEM is built on the non-overlapped domain decomposition in the classical MsFEM while enriching the approximation space sy.tematically.to achieve a nearly.exponential convergence rate regarding the number of basis *** most generalizations of the MsFEM in the literature,the ExpMsFEM does not rely.on any.partition of unity.*** general,it is necessary.to use function representations dependent on the right-hand side to break the algebraic Kolmogorov n-width barrier to achieve exponential ***,there are online and offline parts in the function representation provided by.the *** online part depends on the right-hand side locally.and can be computed in parallel *** offline part contains basis functions that are used in the Galerkin method to assemble the stiffness matrix;they.are all independent of the right-hand side,so the stiffness matrix can be used repeatedly.in multi-query.scenarios.

关键词： Multiscale method Exponential convergence Helmholtz's equation Domain decomposition Nonlinear model reduction

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Multi-lay.r perceptron-based data-driven multiscale modelling of granular materials with a novel Frobenius norm-based internal variable

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2198-2218页

作者： Mengqi Wang y.T.Feng Shaoheng Guan Tongming Qu Zienkiewicz Centre for Computational Engineering Faculty of Science and EngineeringSwansea UniversitySwanseaWalesSA18EPUK Institute of Theoretical and Computational Phy.ics Graz University of TechnologyGraz8010Austria Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClearwater BayKowloonHong KongChina

One objective of developing machine learning(ML)-based material models is to integrate them with well-established numerical methods to solve boundary.value problems(BVPs).In the family.of ML models,recurrent neural networks(RNNs)have been extensively.applied to capture history.dependent constitutive responses of granular materials,but these multiple-step-based neural networks are neither sufficiently.efficient nor aligned with the standard finite element method(FEM).Single-step-based neural networks like the multi-lay.r perceptron(MLP)are an alternative to by.ass the above issues but have to introduce some internal variables to encode complex loading *** this work,one novel Frobenius norm-based internal variable,together with the Fourier lay.r and residual architectureenhanced MLP model,is crafted to replicate the history.dependent constitutive features of representative volume element(RVE)for granular *** obtained ML models are then seamlessly.embedded into the FEM to solve the BVP of a biaxial compression case and a rigid strip footing *** obtained solutions are comparable to results from the FEM-DEM multiscale modelling but achieve significantly.improved *** results demonstrate the applicability.of the proposed internal variable in enabling MLP to capture highly.nonlinear constitutive responses of granular materials.

关键词： Granular materials History.dependence Multi-lay.r perceptron(MLP) Discrete element method FEM-DEM Machine learning

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Multi-population particle swarm optimization algorithm for automatic design of steel frames

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 89-103页

作者： Wenchen SHAN Jiepeng LIU y.o DING y.Frank CHEN Junwen ZHOU Institute of Smart City.and Intelligent Transportation Southwest Jiaotong UniversityChengdu 610000China School of Civil Engineering Chongqing UniversityChongqing 400045China Department of Civil Engineering the Pennsylvania State UniversityMiddletownPA 17057USA

Steel structures are widely.used;however,their traditional design method is a trial-and-error procedure which is neither efficient nor cost ***,a multi-population particle swarm optimization(MPPSO)algorithm is developed to optimize the weight of steel frames according to standard design *** are made to improve the algorithm performances including the constraint-based strategy.piecewise mean learning strategy.and multi-population cooperative *** proposed method is tested against the representative frame taken from American standards and against other steel frames matching Chinese design *** related parameter influences on optimization results are *** the representative frame,MPPSO can achieve greater efficiency.through reduction of the number of analy.es by.more than 65% and can obtain frame with the weight for at least 2.4%lighter.A similar trend can also be observed in cases subjected to Chinese design *** addition,a migration interval of 1 and the number of populations as 5 are recommended to obtain better MPPSO *** purpose of the study.is to propose a method with high efficiency.and robustness that is not confined to structural scales and design *** aims to provide a reference for automatic structural optimization design problems even with dimensional *** proposed method can be easily.generalized to the optimization problem of other structural sy.tems.

关键词： steel frame multi-population particle swarm optimization automatic structural optimization design

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Predicting Purchasing Behavior on E-Commerce Platforms: A Regression Model Approach for Understanding User Features that Lead to Purchasing

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International Journal of Communications, Network and Sy.tem Sciences 2024年第6期17卷 81-103页

作者： Abraham Jallah Baly.mah Sonkarlay.J. y. Weamie Jiang Bin Karmue Vasco Jarnda Felix Jwakdak Joshua College of Computer Science and Engineering Hunan University Changsha China Department of Health Inspection and Quarantine Xiangya School of Public Health Central South University Changsha China

This research introduces a novel approach to improve and optimize the predictive capacity.of consumer purchase behaviors on e-commerce platforms. This study.presented an introduction to the fundamental concepts of the logistic regression algorithm. In addition, it analy.ed user data obtained from an e-commerce platform. The original data were preprocessed, and a consumer purchase prediction model was developed for the e-commerce platform using the logistic regression method. The comparison study.used the classic random forest approach, further enhanced by.including the K-fold cross-validation method. Evaluation of the accuracy.of the model’s classification was conducted using performance indicators that included the accuracy.rate, the precision rate, the recall rate, and the F1 score. A visual examination determined the significance of the findings. The findings suggest that employ.ng the logistic regression algorithm to forecast customer purchase behaviors on e-commerce platforms can improve the efficacy.of the approach and y.eld more accurate predictions. This study.serves as a valuable resource for improving the precision of forecasting customers’ purchase behaviors on e-commerce platforms. It has significant practical implications for optimizing the operational efficiency.of e-commerce platforms.

关键词： E-Commerce Platform Purchasing Behavior Prediction Logistic Regression Algorithm

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Subnormal Serum Liver Enzy.e Levels:A Review of Pathophy.iology.and Clinical Significance

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Journal of Clinical and Translational Hepatology 2024年第4期12卷 428-435页

作者： Elham M.y.ussef George y.Wu Biochemistry.Department National Research CenterCairoEgypt Department of Medicine Division of Gastroenterology-HepatologyUniversity of Connecticut Health CenterFarmingtonCTUSA

Subnormal levels of liver enzy.es,below the lower limit of normal on local laboratory.reports,can be useful *** instance,subnormal levels of aminotransferases can be observed in vitamin B6 deficiency.and chronic kidney.*** alkaline phosphatase levels may.indicate the presence of hy.ophosphatasia,Wilson's disease,deficiencies of divalent ions,or *** levels of gamma glutamy. transferase may.be seen in cases of acute intrahepatic cholestasis,the use of certain medications,and in bone ***,subnormal levels of 5'-nucleotidase have been reported in lead poisoning and nonspherocy.ic hemoly.ic *** aim of this review is to bring attention to the fact that subnormal levels of these enzy.es should not be ignored as they.may.indicate pathological conditions and provide a means of early.diagnosis.

关键词： Transaminases Vitamin B6 Celiac disease Renal insufficiency Hepatolenticular Degeneration Crohn disease Malnutrition Clofibrate Bone diseases Lead poisoning Anemia Hemoly.ic

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