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3D finite element method （FEM） simulation of groundwater flow during backward erosion piping

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Frontiers of Structural and Civil Engineering 2014年第2期8卷 160-166页

作者： Kristine VANDENBOER Vera van beek Adam BEZUIJEN Department of Civil Engineering Ghent University Ghent 9000 Belgium Deltares Delft 2628 Netherlands Section Geoengineering Delft University of Technology Delft 2628 Netherlands

Backward erosion piping is an important failure mechanism for cohesive water retaining structures which are founded on a sandy aquifer. At present, the prediction models for safety assessment are often based on 2D assumptions. In this work, a 3D numerical approach of the groundwater flow leading to the erosion mechanism of backward erosion piping is presented and discussed. Comparison of the 2D and 3D numerical results explicitly demonstrates the inherent 3D nature of the piping phenomenon. In addition, the influence of the seepage length is investigated and discussed for both piping initiation and piping progression. The results clearly indicate the superiority of the presented 3D numerical model compared to the established 2D approach. Moreover, the 3D numerical results enable a better understanding of the complex physical mechanism involved in backward erosion piping and thus can lead to a significant improvement in the safety assessment of water retaining structures.

关键词： backward erosion piping groundwater flow 3D finite element method (FEM)

Systematic coarse-graining of epoxy resins with machine learning-informed energy renormalization

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npj Computational Materials 2021年第1期7卷 1529-1540页

作者： Andrea Giuntoli Nitin K.Hansoge Anton van beek Zhaoxu Meng Wei Chen Sinan Keten Department of Civil&Environmental Engineering Northwestern University2145 Sheridan RoadEvanstonIL 60208-3109USA Center for Hierarchical Materials Design Northwestern University2205 Tech DriveEvanstonIL 60208-3109USA Department of Mechanical Engineering Northwestern University2145 Sheridan RoadEvanstonIL 60208-3109USA Department of Mechanical Engineering Clemson University208 Fluor Daniel EIBClemsonSC 29634-0921USA

A persistent challenge in molecular modeling of thermoset polymers is capturing the effects of chemical composition and degree of crosslinking(DC)on dynamical and mechanical properties with high computational *** established a coarse-graining(CG)approach combining the energy renormalization method with Gaussian process surrogate models of molecular dynamics *** allows a machine-learning informed functional calibration of DC-dependent CG force field *** versatile epoxy resins consisting of Bisphenol A diglycidyl ether combined with curing agent of either 4,4-Diaminodicyclohexylmethane or polyoxypropylene diamines,we demonstrated excellent agreement between all-atom and CG predictions for density,Debye-Waller factor,Young’s modulus,and yield stress at any *** further introduced a surrogate model-enabled simplification of the functional forms of 14 nonbonded calibration parameters by quantifying the uncertainty of a candidate set of calibration *** framework established provides an efficient methodology for chemistry-specific,large-scale investigations of the dynamics and mechanics of epoxy resins.

关键词： functions resins epoxy

Effect of viscosity on the avalanche dynamics and flow transition of wet granular matter

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Particuology 2021年第6期19卷 64-75页

作者： Jens H.Kasper Vanessa Magnanimo Sjoerd D.M.de Jong Arjan beek Ahmed Jarray Multi-Scale Mechanics(MSM) Thermal and Fluid EngineeringFaculty of Engineering Technology.University ofTwenteP.O.Box 2177500 AE EnschedeThe Netherlands Construction Management and Engineering(CME) Faculty of Engineering TechnologyUniversity ofTwenteP.O.Box 2177500 AE EnschedeThe Netherlands

The dynamic behaviour of granular flows is important in geo-mechanics and industrial applications,yet poorly *** studied the effects of liquid viscosity and particle size on the dynamics of wet granular material flowing in a slowly rotating drum,in order to detect the transition from the avalanching to the continuous flow regime.A discrete element method(DEM)model,in which contact forces and cohesive forces were considered,was employed to simulate this flow *** model was validated experimentally,using glass beads in a wooden drum and water–glycerol mixtures to tune the liquid *** DEM simulations showed comparable results to the experiments in terms of average slope angle and avalanche *** observed that the avalanche amplitude,flow layer velocity and granular temperature decrease as the liquid viscosity *** effect is more pronounced for smaller sized *** increase in viscous forces causes the flowing particles to behave as a bulk,pushing the free surface towards a convex *** addition,avalanches become less pronounced and the granular flow transitions from the avalanching regime to the continuous *** avalanching flow regime is marked by intermittent rigid body movement of the particulate bed and near-zero drops in the granular temperature,while no rigid body movement of the bed occurs in the continuous flow *** identified the avalanching-continuous flow transition region as a function of a dimensionless granular Galileo number.

关键词： Granular avalanche Transition Cohesion Viscosity Rotary drum DEM

Constructing and Cleaning Identity Graphs in the LOD Cloud

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Data Intelligence 2020年第3期2卷 323-352页

作者： Joe Raad Wouter beek Frank van Harmelen Jan Wielemaker Nathalie Pernelle Fatiha Saïs Deptartment of Computer Science Vrije UniversityAmsterdamThe Netherlands Computer Science Research Laboratory(LRI)of the University Paris Sud French National Centre for Scientific ResearchParis Saclay UniversityOrsayFrance

In the absence of a central naming authority on the Semantic Web,it is common for different data sets to refer to the same thing by different *** multiple names are used to denote the same thing,owl:sameAs statements are needed in order to link the data and foster *** that date back as far as 2009,observed that the owl:sameAs property is sometimes used *** our previous work,we presented an identity graph containing over 500 million explicit and 35 billion implied owl:sameAs statements,and presented a scalable approach for automatically calculating an error degree for each identity *** this paper,we generate subgraphs of the overall identity graph that correspond to certain error *** show that even though the Semantic Web contains many erroneous owl:sameAs statements,it is still possible to use Semantic Web data while at the same time minimising the adverse effects of misusing owl:sameAs.

关键词： Linked Open Data Identity Quality Reasoning

EXPLORING THE RECYCLING OF MANURE FROM URBAN LIVESTOCK FARMS:A CASE STUDY IN ETHIOPIA

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Frontiers of Agricultural Science and Engineering 2021年第1期8卷 159-174页

作者： Solomon Tulu TADESSE Oene OENEMA Christy van beek Fikre Lemessa OCHO Department of Horticulture and Plant Sciences College of Agriculture and Veterinary MedicineJimma UniversityJimmaEthiopia Department of Soil Quality Wageningen University and Research6700 AA Wageningenthe Netherlands Wageningen Environmental Research 6700 AA Wageningenthe Netherlands SoilCares Foundation Nieuwe Kanaal 7c6709 PA Wageningenthe Netherlands

Urban population growth is driving the expansion of urban and peri-urban agriculture(UPA)in developing *** is providing nutritious food to residents but the manures produced by UPA livestock farms and other wastes are not properly *** paper explores the effects of four scenarios:(1)a reference scenario(business as usual),(2)increased urbanization,(3)UPA intensification,and(4)improved technology,on food-protein self-sufficiency,manure nitrogen(N)recycling and balances for four different zones in a small city(Jimma)in Ethiopia during the period *** N mass flow model with data from farm surveys,field experiments and literature was used.A field experiment was conducted and N use efficiency and N fertilizer replacement values differed among the five types of composts derived from urban livestock manures and kitchen *** N use efficiency and N fertilizer replacement values were used in the N mass flow *** manures were the main organic wastes in urban areas,although only 20 to 40%of animal-sourced food consumed was produced in UPA,and only 14 to 19%of protein intake by residents was *** indicate that manure production in UPA will increase 3 to 10 times between 2015 and 2050,depending on urbanization and UPA *** 13 to 38%of manure N will be recycled in ***-gate N balances of UPA livestock farms will increase to>1 t·ha−1 in *** livestock productivity and feed protein conversion to animal-sourced food will roughly halve manure N *** of waste recycling were high and indicate the need for government *** of these senarios are wake-up calls for all stakeholders and indicate alternative pathways.

关键词： compost food self-sufficiency livestock production nitrogen balance nitrogen use efficiency scenario analysis

Use of incipient motion data for backward erosion piping models

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International Journal of Sediment Research 2019年第5期34卷 401-408页

作者： Vera M.van beek Bryant A.Robbins Gijs J.C.M.Hoffmans Adam Bezuijen Leo C.van Rijn Deltares U.S.Army Engineer Research and Development Center Ghent University Leovanrijn-Sediment-Consultancy

Backward erosion piping involves the gradual removal of granular material under the action of water flow from the foundation of a dam or levee, whereby shallow pipes are formed that grow in the direction opposite to the flow. This pipe-forming process can ultimately lead to failure of a water-retaining structure and is considered one of the most important failure mechanisms for dikes and levees in the Netherlands and the United States. Modeling of this mechanism requires the assessment of hydraulic conditions in the pipe, which are controlled by the particle equilibrium at the pipe wall. Since the pipe’s dimensions are controlled by the inflow to the pipe from the porous medium, the flow through the pipe is thought to be laminar for fine-to medium-grained sands. The literature provides data for incipient motion in laminar flow, which is reviewed here and complemented with data from backward erosion experiments. The experiments illustrate the applicability of the laminar incipient motion data to determine the erosion pipe dimensions and corresponding pipe hydraulics for fine-to medium-grained sands, for the purpose of backward erosion piping modeling.

关键词： Internal erosion Backward erosion piping Cylindrical test Incipient motion Dikes Levees

热年代学年龄温度法和年龄高程法的应用条件:对采样策略及年龄表达的启示

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地学前缘 2011年第6期18卷 347-357页

作者：曹凯王国灿 Peter van der beek 中国地质大学地质过程与矿产资源国家重点实验室湖北武汉430074 中国地质大学(武汉)地球科学学院湖北武汉430074 Institut des Sciences de la Terre Université Joseph Fourier

热年代学的年龄温度法和年龄高程法是研究造山带长期构造演化过程的常用方法。相对于年龄温度法而言,年龄高程法在计算岩石剥露速率上的优势在于回避了地温梯度的假设,但前提条件中最重要的方面则要求地温梯度达到稳定状态。然而,地温... 详细信息

热年代学的年龄温度法和年龄高程法是研究造山带长期构造演化过程的常用方法。相对于年龄温度法而言,年龄高程法在计算岩石剥露速率上的优势在于回避了地温梯度的假设,但前提条件中最重要的方面则要求地温梯度达到稳定状态。然而,地温场通常会受到地形变化、地表剥露速率、断层活动及岩浆侵入等作用的干扰,导致地温梯度处于非稳定状态。此时,针对造山带长期演化过程中的具体问题采取合理的热年代学采样策略以及对年龄信息的有效提取方法是十分必要的。

关键词：热年代学年龄温度法年龄高程法地温梯度采样策略

Quality Assurance and Curriculum Design in the Netherlands

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中国高等教育评论 2017年第2期 77-86页

作者： Karin van beek Marije Markus Marije van Vilsteren Commit Learning and Development the Netherlands Samara L&O the Netherlands Movimento Onderwijs the Netherlands

This article explains the phasing in the design of associate degree programs in the *** associate degree is a degree on Level5 and is described in this *** associate degree programs organize themselves in new developed Regional Associate *** teams consists of teachers from different *** design team leader’s tasks and focus within the different phases in designs is addressed.

关键词： Level 5 Associate Degree curriculum development design teams in education phases of designing curricula pioneering education team leadership

Lung cancer screening: Computed tomography or chest radiographs?

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World Journal of Radiology 2015年第8期7卷 189-193页

作者： Edwin JR van beek Saeed Mirsadraee John T Murchison Clinical Research Imaging Centre Queen’s Medical Research Institute University of Edinburgh Department of Radiology Royal Infirmary of Edinburgh

Worldwide, lung cancer is the leading cause of mortalitydue to malignancy. The vast majority of cases of lung cancer are smoking related and the most effective way of reducing lung cancer incidence and mortality is by smoking cessation. In the Western world, smoking cessation policies have met with limited success. The other major means of reducing lung cancer deaths is to diagnose cases at an earlier more treatable stage employing screening programmes using chest radiographs or low dose computed tomography. In many countries smoking is still on the increase, and the sheer scale of the problem limits the affordability of such screening programmes. This short review article will evaluate the current evidence and potential areas of research which may benefit policy making across the world.

关键词： Lung cancer Chest radiograph Computed tomography Screening Health economics