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A coupled Soil-Fluid-Structure Simulation of the Near-Field Earthquake Effects on Gravity Type Quay-Walls

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china Ocean Engineering 2013年第4期27卷 481-494页

作者： M.Zeinoddini h.Matin Nikoo F.Ahmadpour Faculty of civil Engineering K.N.Toosi University of Technology

This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface （FSI） elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach （IDA） is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.

关键词： coastal structure gravity quay-wall near-fault earthquake Incremental Dynamic Analysis (IDA)

Novel Nanostructured MnO_2 Prepared by Pulse Electrodeposition:characterization and Electrokinetics

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Journal of Materials Science & Technology 2008年第6期24卷 857-862页

作者： h.Adelkhani M.Ghaemi S.M.Jafari Department of chemistry School of SciencesTarbiat Modares UniversityP.O.Box 14115-175TehranIran Department of chemistry Science FacultyGolestan UniversityP.O.Box 49138-15739GorganIran Department of Mathematics Science FacultyGolestan UniversityGorganIran

Pulse current technique was applied for the preparation of novel electroactive manganese dioxide and possible influences of different electrokinetic phenomena on material characteristics were discussed. The characterizations of pulse deposited sample （pcMD） were carried out by different techniques： Fourier transform infrared spectroscopy （FTIR）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, Raman spectroscopy, and atomic force microscopy （AFM）. SEM image revealed that pulse current could improve the current distribution. This was confirmed by AFM images showing a decrease in surface roughness of pcMDs in comparison to amorphous samples, which were deposited by direct current （dcMD）. higher distortion of MnO6 octahedral environment of dcMD was detected by FTJR and Raman spectroscopy. cyclic voltammetric （cV） measurements showed a generally higher energy level drained from the second electron discharge of pcMD. This is mainly attributed to a higher surface area and a lower diffusion pass of electrons and protons arisen via a rather unique nanostructural arrangement of pcMD grains. Results indicate a higher surface area available for the non homogenous second electron discharge of pcMD grains.

关键词： Manganese dioxide Pulse electrodeposition Nano-structures Electrocrystallization

comparative mammalian cell cytotoxicity of wastewater with elevated bromide and iodide after chlorination,chloramination, or ozonation

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Journal of Environmental Sciences 2017年第8期29卷 296-301页

作者： Shengkun Dong Thanh h.Nguyen Michael J.Plewa Department of civil and Environmental Enoineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA Department of crop Sciences University of Illinois at Urbana-Champaign Urbana IL 61801 USA Safe Global Water Institute Uniuersity of Illinois at Urbana-Champaign Urbana IL 61801 USA

Recycling wastewater is becoming more common as communities around the world try to better control their water resources against an increased frequency of either prolonged droughts or intense flooding. For communities in coastal areas, wastewaters may contain elevated levels of bromide（Br^-） and iodide（I^-） from seawater intrusion or high mineral content of source waters. Disinfection of such wastewater is mandatory to prevent the spread of pathogens, however little is known about the toxicity of wastewater after disinfection in the presence of Br^-and I^-. In this study we compared the induction of chronic cytotoxicity in mammalian cells in samples of municipal secondary wastewater effluent amended with elevated levels of Br^-/I^-after disinfection by chlorine, chloramines or ozone to identify which disinfection process generated wastewater with the lowest level of adverse biological response. chlorination increased mammalian cell cytotoxicity by 5times as compared to non-disinfected controls. chloramination produced disinfected wastewater that expressed 6.3 times more cytotoxicity than the non-disinfected controls and was 1.3 times more cytotoxic than the chlorinated samples. Ozonation produced wastewater with cytotoxicity comparable to the non-disinfected controls and was at least 4times less cytotoxic than the chlorine disinfected wastewaters. These results indicate that compared to chlorination and chloramination, ozonation of wastewater with high Br^-/Ilevels yielded the lowest mammalian cell cytotoxicity, suggesting its potential as a more favorable method to disinfect wastewater with minimizing the biological toxicity in mind.

关键词： cytotoxicity Ozonation chlorination chloramination Wastewater Bromide Iodide Disinfection

Optimization of Mass Bleed control for Base Drag Reduction of Supersonic Flight Bodies

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Journal of Thermal Science 2006年第3期15卷 206-212页

作者： Y.-K.Lee h.-D.Kim School of Mechanical Engineering Andong National University388 Songcheon-dongAndong760-749Korea

The minimization of base drag using mass bleed control is examined in consideration of various base to orifice exit area ratios for a body of revolution in the Mach 2.47 freestream Axisymmetric, compressible, rmss-averaged Navier-Stokes equations are solved using the standard k-ω model, a fully implicit finite volume scheme, and a second order upwind scheme. Base flow charcteristics are explained mgaarding the base configuration as well as the injection parameter which is defined as the mass flow rate of bleed jet non-dimensionalized by the product of the base area and fieestream mass flux. The results obtained through the present study show that for a smaller base area, the optimum mass bleed condition leading to minimum base drag occurs at relatively larger mass bleed, and a lalger orifice exit can offer better drag control.

关键词： base drag mass bleed drag reduction separation supersonic flow

A hOMOTOPY METhOD OF SWITchING SOLUTION BRANchES AT ThE PITchFORK BIFURcATION POINT

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Journal of computational Mathematics 2001年第3期19卷 299-308页

作者： cong, Y.-h. Zhu, Z.-Y. college of Mathematical Sciences Shanghai Teachers University Shanghai 200234 China

Provides information on a study which proposed a continuation method for switching solution branches at a pitchfork point. Problem of the standard pitchfork; Information on the systems of equations; Numerical examples... 详细信息

关键词： homotopy method switching solution branches pitchfork point

AN ANALYSIS OF SUBGRID-RESOLVED ScALE INTERAcTIONS WITh USE OF RESULTS FROM DIREcT NUMERIcAL SIMULATIONS

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Acta Mechanica Sinica 1999年第2期15卷 108-115页

作者： h. Gong S. chen G.W. he Environment Safety and Health Division and Center for Nonlinear Studies Los Alamos National Laboratory Los Alamos NM 87545 USA LNM Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Subgrid nonlinear interaction and energy transfer are analyzed using direct numerical simulations of isotropic turbulence. Influences of cutoff wave number at different ranges of scale on the energetics and dynamics have been investigated. It is observed that subgrid-subgrid interaction dominates the turbulent dynamics when cut-off wave number locates in the energy-containing range while resolved-subgrid interaction dominates if it is in the dissipation range. By decomposing the subgrid energy transfer and nonlinear interaction into ‘forward’ and ‘backward’ groups according to the sign of triadic interaction, we find that individually each group has very large contribution, but the net of them is much smaller, implying that tremendous cancellation happens between these two groups.

关键词： subgrid nonlinear interaction energy transfer large eddy simulation (LES) subgrid scale (SGS) direct numerical simulation isotropic turbulence

A Gradient Model for Young's Modulus and Surface Electrode Resistance of Ionic Polymer-Metai composite

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Acta Mechanica Solida Sinica 2019年第6期32卷 754-766页

作者： h.G.Liu K.Xiong M.Wang Faculty of civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013China State Key Laboratory of Mechanics and control of Mechanical Structures Nanjing University of Aeronautics and Astronauticsf Nanjing 210016China

A new model is proposed to estimate Young's modulus and surface electrode resistance of the ionic polymer-metai composite(IPMc)with a gradient distribution of micros true *** entire IPMc electrode is divided into two parts,i.e.,the porous metal electrode and the gradient polymer-metai composite electrode,according to the geometrie properties of the electroless plated metal *** validity and accuracy of the model are justified by comparing with the experimental observations of IPMc *** differences between model predictions and experimental data of Young's modulus and surface resistance of IPMc samples are+6.8%and-5.5%,respectively,indicating a reasonably good agreement.

关键词： Ionic polymer-metai composite Gradient electrode model Young's modulus Resistance

Static and Dynamic Study of a Wind Turbine Blade with horizontal Axis

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Journal of Environmental Science and Engineering 2011年第9期5卷 1167-1174页

作者： h. hamdi c. Mrad R. Nasri A. hamdi Department of Mechanical Engineering Higher Institute of Technological Studies of Rades Rades 2098 Tunisia Department of Mechanical Engineering National School of Engineers of Tunis University Tunis El Manar Le Belvedere 1002 Tunisia LRccP 60 Rue Auber Vitry Sur Seine 94400 France

In this work the authors present a calculation process of the blades for wind turbine with horizontal axis. It is about a blade discretized by the finite element method （FEM） in order to determine the gyroscopic effect during its rotation at a high speed. A blade must have the maximum output and resist to aerodynamic loads distributed over its length, which are related to its geometrical characteristics and the speed of the wind. For that, the authors wrote the relations whom determine these loads according to the flow speed of the wind, then, the authors integrated them in the laws of structure mechanics to obtain the motion equations of the blade. This process was applied to a twisted blade with a length of 1.9 m, built out of pressed aluminum sheet with a profile of the type NAcA; this profile gives the best aerodynamic output. This blade is an element of a three-bladed propeller for wind turbine of maximum power 5 kW. Finally, we visualized its deformations and then the authors checked its holding in service.

关键词： Wind turbine aerodynamic load static and dynamic behavior gyroscopic effect.

Ion motion effects on the generation of short-cycle relativistic laser pulses during radiation pressure acceleration

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high Power Laser Science and Engineering 2014年第2期2卷 1-7页

作者： W.P.Wang X.M.Zhang X.F.Wang X.Y.Zhao J.c.Xu Y.h.Yu L.Q.Yi Y.Shi L.G.Zhang T.J.Xu c.Liu Z.K.Pei B.F.Shen State Key Laboratory of high Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

The effects of ion motion on the generation of short-cycle relativistic laser pulses during radiation pressure acceleration are investigated by analytical modeling and particle-in-cell simulations. Studies show that the rear part of the transmitted pulse modulated by ion motion is sharper compared with the case of the electron shutter only. In this study, the ions further modulate the short-cycle pulses transmitted. A 3.9 fs laser pulse with an intensity of 1.33×1021W cm-2is generated by properly controlling the motions of the electron and ion in the simulations. The short-cycle laser pulse source proposed can be applied in the generation of single attosecond pulses and electron acceleration in a small bubble regime.

关键词： radiation pressure acceleration short-cycle pulses particle-in-cell simulations.