检索结果-南通市图书馆

Influence of particle shape on the erodibility of non-cohesive soil： Insights from coupled CFD-DEM simulations

作者： (美)Mike moran (美)bill Hunt

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

Particuology 2018年第4期16卷 12-24页

作者： Yuan Guo Yang Yang Xiong (bill) Yu Department of Civil Engineering Case Western Reserve University 2104 Adelbert Road Bingharn 269 Cleveland OH 44106-7201 USA Department of Electrical Engineering and Computer Science Case Western Reserve University 2104 Adelbert Road Bingharn 203D Cleveland OH 44106-7201 USA Departrnent of Civil Engineering Case Western Reserve University 2104 Adelbert Road Bingharn 206 Cleveland OH 44106- 7201 USA

Soil erosion is a critical process that is being studied in soil science, hydraulic engineering, and geotech- nical engineering. Among many societal and environmental impacts, soil erosion is a major cause for the failures of bridges. The erodibility of soil is determined by its physical and geochemical properties and is also affected by surrounding biological activities. In most of the current models for soil erosion, erodibility of non-cohesive soil is characterized by its median grain size （Dso）, density, and porosity. The contribution to erodibility of the irregular shape of soil grains, which plays an important role in the mechanical and hydraulic properties of coarse-grained soils, is generally ignored. In this paper, a coupled computational fluid dynamics and discrete element method model is developed to analyze the influence of the shape of sand grain on soil erodibility. A numerical model for the drag force on spherical and non-spherical particles is verified by using the results from physical free settling experiments. Erosion of sand grains of different shapes is simulated in a virtual erosion function apparatus, a laboratory device used to mea- sure soil erodibility. The simulation results indicate that the grain shape has major effects on erodibility. Spherical particles do not show a critical velocity because of their low rolling resistance, but a critical velocity does exist for angular particles owing to grain interlocking. The erosion rate is proportional to the flow velocity for both spherical and non-spherical particles. The simulation result for angular particle erosion is fairly consistent with the experimental observations, implying that grain shape is an important factor affecting the erodibility of non-cohesive soils.

关键词： CFD-DEM Soil erosion Grain shape Erodibility of coarse-grained soil Erosion function apparatus mode

Comparison between gradient based UCODE2005 and the ensemble Kalman Filter for transient groundwater flow inverse modeling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2017年第5期60卷 899-909页

作者： TONG JuXiu bill X HU YANG JinZhong Key Laboratory of Groundwater Cycle and Environment Evolution (China University of Geosciences) Ministry of Education Beijing 100083 China School of Water Resources and Environment China University of Geosciences Beijing 100083 China Department of Earth Ocean and Atmospheric Science/Geological Sciences 108 Carraway Building 909 Antarctic Way Florida State University Tallahassee Florida 32306 USA State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China

Gradient based UCODE_2005 and data assimilation based on the Ensemble Kalman Filter(EnKF) are two different inverse methods. A synthetic two-dimensional flow case with four no-flow boundaries is used to compare the UCODE_2005 with the Ensemble Kalman Filter(EnKF) for their efficiency to inversely calculate and calibrate a hydraulic conductivity field based on hydraulic head data. A zonal, random heterogeneous conductivity field is calibrated by assimilating the time series of heads observed in monitoring wells. The study results indicate that the two inverse methods, UCODE_2005 and EnKF, could be used to calibrate the hydraulic conductivity field to a certain degree. More available observations and information about the conductivity field, more accurate inverse results will be obtained for the UCODE_2005. On the other hand, for a realistic zonal heterogeneous hydraulic conductivity field, EnKF can only efficiently determine the hydraulic conductivity field at the first several assimilated time steps. The results obtained by the UCODE_2005 look better than those by the EnKF. This is possibly due to the fact that the UCODE_2005 uses observed head data at every time step, while EnKF can only use observed heads at first several steps due to the filter divergence problem.

关键词： Inverse methods UCODE2005 Ensemble Kalman Filter Heterogeneous hydraulic conductivity Filter divergence

Interlayer shear of nanomaterials:Graphene–graphene,boron nitride–boron nitride and graphene–boron nitride

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2017年第3期30卷 234-240页

作者： Yinfeng Li Weiwei Zhang bill Guo Dibakar Dattac Department of Engineering Mechanics School of Naval Architecture Ocean and Civil Engineering (State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration) Shanghai Jiao Tong University Shanghai 200240 China Department of Materials Science and Engineering University of Pennsylvania Philadelphia PA 19104 USA Department of Mechanical and Industrial Engineering Newark College of Engineering New Jersey Institute of Technology Newark NJ 07102 USA Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education Nanjing University of Aeronautics and Astronautics Nanjinq 210016 China

In this paper, the interlayer sliding between graphene and boron nitride （h-BN） is studied by molecular dynamics simulations. The interlayer shear force between h-BN/h-BN is found to be six times higher than that of graphene/graphene, while the interlayer shear between graphene/h-BN is approximate to that of graphene/graphene. The graphene/h- BN heterostructure shows several anomalous interlayer shear characteristics compared to its bilayer counterparts. For graphene/graphene and h-BN/h-BN, interlayer shears only exit along the sliding direction while interlayer shear for graphene/h-BN is observed along both the translocation and perpendicular directions. Our results provide significant insight into the interlayer shear characteristics of 2D nanomaterials.

关键词： Friction Interlayer shear Graphene Hexongal boron nitride Molecular dynamics

Unique Clinical Features of Curaderm when Treating Skin Cancers

在线全文

学校读者我要写书评

暂无评论

A holistic computational model for prediction of clay suspension structure

Journal of Cancer Therapy（癌症治疗） 2024年第1期

作者： Tania Robyn Chase Kai Elliot Cham bill Elliot Cham

来源：博看期刊评论

在线全文

博看期刊

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2019年第4期34卷 345-354页

作者： Yuan Guo Xiong (bill) Yu Department of Civil Engineering Case Western Reserve University

The formation of clay suspensions involves complex interactions among clay particles subjected to the geochemical environment during the sedimentation process. The structural characteristics have a major influence on the physical and mechanical behavior of the suspension. A modeling framework involving a Discrete Element Method(DEM) model with customized particle mechanical interactions is proposed in this paper for the holistic prediction of the physical structure of clay suspensions. The particle interaction force model is based on the Derjaguin, Landau, Verwey, and Overbeek(DLVO) theory that accounts for electrostatic repulsion, van der Waals attraction, contact repulsion, etc. Kaolinite is used as the model clay to demonstrate the model performance. The surface charge density of kaolinite is obtained through Atomic Force Microscope(AFM) force measurement and is implemented in the particle interaction force model in the subsequent simulations. Influencing factors, such as centrifugal acceleration, ionic concentration, platy structure of particles, and particle size, on the formation of kaolinite suspensions are studied with the numerical model and compare favorably well with the experimental data. This work lays down a unique framework consisting of computational modeling and microscale characterization of clay particles to holistically predict the characteristics of clay suspensions, which paves the basis to model and predict their bulk physical and mechanical behavior.

关键词： Clay suspension Discrete element method DLVO theory Atomic force microscope Kaolinite Surface potential

Designing Interactions 1

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Identification of hydraulic conductivity distributions in density dependent flow fields of submarine groundwater discharge modeling using adjoint-state sensitivities

丛书名： EBL-Schweitzer

2007年

作者： bill Moggridge

Digital technology has changed the way we interact with everything from the games we play to the tools we use at work. Designers of digital technology products no longer regard their ... 详细信息

ISBN: (纸本)9780262134743

Digital technology has changed the way we interact with everything from the games we play to the tools we use at work. Designers of digital technology products no longer regard their job as designing a physical object--beautiful or utilitarian--but as designing our interactions with it. In Designing Interactions, award-winning designer bill Moggridge introduces us to forty influential designers who have shaped our interaction with technology. Moggridge, designer of the first laptop computer (the GRiD Compass, 1981) and a founder of the design firm IDEO, tells us these stories from an industry insider's viewpoint, tracing the evolution of ideas from inspiration to outcome. The innovators he interviews--including Will Wright, creator of The Sims, Larry Page and Sergey Brin, the founders of Google, and Doug Engelbart, bill Atkinson, and others involved in the invention and development of the mouse and the desktop--have been instrumental in making a difference in the design of interactions. Their stories chart the history of entrepreneurial design development for *** and his interviewees discuss such questions as why a personal computer has a window in a desktop, what made Palm's handheld organizers so successful, what turns a game into a hobby, why Google is the search engine of choice, and why 30 million people in Japan choose the i-mode service for their cell phones. And Moggridge tells the story of his own design process and explains the focus on people and prototypes that has been successful at IDEO--how the needs and desires of people can inspire innovative designs and how prototyping methods are evolving for the

关键词： Humancomputer interaction.

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第4期59卷 770-779页

作者： HU bill X CAO YanZhao ZHAO WeiDong BAO Feng School of Water Resources and Environmental Sciences China University of Geosciences Department of Geological Sciences Florida State University Department of Mathematics and Statistics Auburn University School of Mathematics Shandong University

A mathematical optimal control method is developed to identify a hydraulic conductivity distribution in a density dependent flow field. Using a variational method, the adjoint partial differential equations are obtained for the density-dependent state equations used for the saline aquifer water flow. The adjoint equations are numerically solved in through a finite difference method. The developed method is applied to identify the hydraulic conductivity distribution through the numerical solution of an optimal control problem. To demonstrate the effectiveness of the optimal control method, three numerical experiments are conducted with artificial observation data. The results indicate that the developed method has the potential to accurately identify the hydraulic conductivity distribution in a saline water aquifer flow system.

关键词： Variable-density flow Hydraulic conductivity Inverse method Adjoint partial differential equation Submarine groundwater discharge

Investigation of La_(9.33)Si_6O_(26) Oxygen Ionic Conductor

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2007年第5期23卷 629-632页

作者： Hong ZHANG Zhicheng LI bill Bergman Xiaodong ZOU School of Materials Science and Engineering Central South University Changsha 410083 China Department of Materials Science and Engineering School of Industrial Engineering and Management Royal Institute of Technology SE 100 44 Stockholm Sweden Structure Chemistry Arrhenius Laboratory Stockholm University SE 10691 Stockholm Sweden

La9.335i6O26 oxygen ionic conductor was synthesized by solid state reaction method. Its structure was deter- mined by single-crystal X-ray diffraction analysis at room temperature. The results showed that La9.33Si6O26 oxide has the apatite structure with space group P63/m. AC impedance measurements indicated that the oxides sintered in nitrogen have much higher conductivity than those sintered in air. The effects of grain boundaries on the conductivity were discussed.

关键词： La9.33Si6O26 Crystal structure Oxygen ionic conductor Conductivity