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Modelling of sediment movement in the surf and swash zones

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Acta Oceanologica Sinica 2015年第2期34卷 137-142页

作者： TOKPOHOZIn n.B. KOUnOUHEWA B. AVOSSEVOU G.y.H. HOUEKPOHEHAM A. AWAnOU C.n. Institut de Mathématiques et de Sciences Physiques (IMSP/UAC) Centre Béninois de la Recherche Scientifique et Technique (CBRST) Laboratoire de Physique du Ray.nnement (LPR/FAST-UAC)

Under the action of marine currents,non-cohesive sediments evolve by bed-load,by saltation or suspension depending on their *** authors have considered that the movement of sediment is bidimensional and modelized the effects of swell by a constant velocitynear the *** we have studied the velocity profile of fluctuating currents near the seabed and studied the movement of sediment in *** results show that in the areas of study（surf and swash）the movement of sediment occurs in a volume,and the evolution of sediment varies from an areato *** obtained theoretical profiles of the position and velocity vectors confirm the observations of several authors.

关键词： non-cohesive sediments sediment dynamics swell trajectory of sediment velocity drive

Microstructural characteristics and mechanical properties of the hot extruded Mg-Zn-y.nd alloys

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Journal of Materials Science & Technology 2021年第1期60卷 44-55页

作者： B.n.Du Z.y.Hu L.y.Sheng D.K.Xu y.X.Qiao B.J.Wang J.Wang y.F.Zheng T.F.Xi Shenzhen Institute Peking UniversityShenzhen 518057China Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Jiangsu University of Science and Technology Zhenjiang 212003China Shenzhen yezhan Electronics Co. LtdShenzhen 518110China

A new type of Mg-Zn-y.nd alloy for degradable orthopedic implants was *** the present study,the Zn and y content was adjusted and their influences on the microstructures and mechanical behaviors were discussed in *** results showed that the as-extruded Mg-Zn-y.nd alloys are mainly composed of fine dynamic recrystallized grains(DRXed grains),la rge unDRXed grains and linearly distributed secondary *** cha nge of Zn content exerts little influence on the grain structure of the extruded Mg-Zn-y.nd alloy,while the increase of y content would hinder the dynamic recrystallization process and the growth of the DRXed grains,thus the size and volume fraction of the equiaxed DRXed grains *** tensile and compressive properties are very little affected by Zn content because of the similar grain *** y content increases,the tensile yield strength(TyS) and ultimate strength(TUS) increase while the elongation decreases,this is caused by a combined strengthening effect of grain refinement,texture,precipitation and *** compressive yield strength(CyS) and ultimate strength(CUS) of Mg-Zn-y.nd alloy with diffe rent y content exhibit a similar tendency as the tensile test.

关键词： Mg-Zn-y.nd alloy Microstructure Tensile properties Compressive properties Basal texture Twin

nonlinear Transient Response of Functionally Graded Material Sandwich Doubly Curved Shallow Shell Using new Displacement Field

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Acta Mechanica Solida Sinica 2018年第1期31卷 108-126页

作者： Z.n.Li y.X.Hao W.Zhang J.H.Zhang College of Mechanical Engineering Beijing Information Science and Technology University College of Mechanical Engineering Beijing University of Technology

In this paper, the nonlinear transient dynamic response of functionally graded material （FGM） sandwich doubly curved shell with homogenous isotropic material core and functionally graded face sheet is analyzed using a new displacement field on the basis of Reddy＇s third-order shear theory for the first time. The equivalent material properties for the FGM face sheet are assumed to obey the rule of simple power law function in the thickness direction. Based on Reddy＇s theory of higher shear deformation, a new displacement field is developed by introducing the secant function into transverse displacement. Four coupled nonlinear differential equations are obtained by apply.ng Hamilton＇s principle and Galerkin method. It is assumed that the FGM sandwich doubly curved shell is subjected to step loading, air-blast loading, triangular loading, and sinusoidal loading, respectively. On the basis of double-precision variable- coefficient ordinary differential equation solver, a new program code in FORTRAn software is developed to solve the nonlinear transient dynamics of the system. The influences of core thickness, volume fraction, core-to-face sheet thickness ratio, width-to-thickness ratio and blast type on the transient response of the shell are discussed in detail through numerical simulation.

关键词： new displacement fields Functionally graded materials Sandwich doubly curvedshell Blast load nonlinear transient response

Hydromagnetic Blood Flow of Sisko Fluid in a non-uniform Channel Induced by Peristaltic Wave

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Communications in Theoretical Physics 2017年第7期67卷 103-110页

作者： A.Zeeshan M.M.Bhatti n.S.Akbar y.Sajjad Government Boys Degree College Afzalpur Mirpur Azad Kashmir Pakistan

In this paper, a smooth repetitive osciflating wave traveling down the elastic walls of a non-uniform two- dimensional channels is considered. It is assumed that the fluid is electrically conducting and a uniform magnetic field is perpendicular to flow. The Sisko fluid is grease thick non-newtonian fluid can be considered equivalent to blood. Taking long wavelength and low Reynolds number, the equations are reduced. The analytical solution of the emerging non-linear differential equation is obtained by employ.ng Homotopy Perturbation Method （HPM）. The outcomes for dimensionless flow rate and dimensionless pressure rise have been computed numerically with respect to sundry concerning parameters amplitude ratio , Hartmann number M, and Sisko fluid parameter bl. The behaviors for pressure rise and average friction have been discussed in details and displayed graphically. numerical and graphical comparison of newtonian and non-newtonian has also been evaluated for velocity and pressure rise. It is observed that the magnitude of pressure rise is maximum in the middle of the channel whereas for higher values of fluid parameter it increases. Further, it is also found that the velocity profile shows converse behavior along the walls of the channel against multiple values of fluid parameter.

关键词： blood flow peristaltic flow Sisko fluid non-uniform channel

Angular Dependence of Lateral and Levitation Forces in Asymmetric Small Magnet/Superconducting Systems

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Chinese Physics Letters 2007年第9期24卷 2700-2703页

作者： H. M. Al-Khateeb M. K. Alqadi F. y. Alzoubi n. y. Ayoub Department of Physics Jordan University of Science and Technology Irbid Jordan School of Applied natural Sciences German Jordanian University Amman Jordan

The dipole-dipole interaction model is used to calculate the angular dependence of lateral and levitation forces on a small permanent magnet and a cylindrical superconductor in the Meissner state ly.ng laterally off the symmetric axis of the cylinder. Under the assumption that the lateral displacement of the magnet is small compared with the physical dimensions of the system, we obtain analytical expressions for the lateral and levitation forces as functions of geometrical parameters of the superconductor as well as the height, the lateral displacement and the orientation of magnetic moment of the magnet. The effect of thickness and radius of the superconductor on the levitation force is similar to that for a symmetric magnet/superconducting cylinder system, but within the range of lateral displacement. The splitting in the levitation force increases with the increasing angle of orientation of the magnetic moment of the magnet. For a given lateral displacement of the magnet, the lateral force vanishes when the magnetic moment is perpendicular to the surface of the superconductor and has a maximum value when the moment is parallel to the surface. For a given orientation of the magnetic moment, the lateral force has a linear relationship with the lateral displacement. The stability of the magnet above the superconducting cylinder is discussed in detail.

关键词： THIn SUPERCOnDUCTInG DISKS MEISSnER STATE MAGnETIC-LEVITATIOn PERMAnEnT-MAGnET CERAMICS CyLInDER SAMPLE

Vibrations in Magnet/Superconductor Levitation Systems

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Chinese Physics Letters 2006年第6期23卷 1641-1644页

作者： F. y. Alzoubi H. M. Al-khateeb M. K. Alqadi n. y. Ayoub Department of Physics Jordan University of Science and Technology Irbid Jordan Department of Physics Yarmouk University Irbid Jordan School of Applied natural Sciences German Jordanian University Amman Jordan

The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction energy, levitation force, magnetic stiffness and frequency of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency increases monotonically up to saturation by increasing the radius of the disc for a particular height of the magnet. In addition, the frequency of vibrations is higher when the system is in the vertical configuration than that when the system is in the horizontal configuration.

关键词： MEISSnER STATE SMALL MAGnET FORCE STIFFnESS SUPERCOnDUCTORS SIZE

Effects of Magnet Size and Geometry on Magnetic Levitation Force

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Chinese Physics Letters 2007年第9期24卷 2664-2666页

作者： M. K. Alqadi H. M. Al-khateeb F. y. Alzoubi n. y. Ayoub Department of Physics Jordan University of Science and Technology Irbid Jordan School of natural Applied Sciences German Jordanian University Amman Jordan

We obtain analytical relations for the levitation force as a function of dimensions of the superconductor-magnet system. The force has been calculated on the basis of the dipole-dipole interaction model. The effect of thickness of the superconductor on the levitation force is investigated. The results show that the influence of geometry and thickness of the magnet becomes significantly large at small levitation distances. Furthermore, approximating the permanent magnet as a point dipole results in an inaccurate estimation of the levitation force.

关键词： MEISSnER STATE

EFFECT OF HEAT TREATMEnT On RECOVERy STRESS OF Fe-18Mn-5Si-8Cr-4ni ALLOy

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 743-746页

作者： Li, n. Wen, y.H. Xu, y.G. Tu, M.J. Li, P.Q. Liu, y.L. Ma, y.L. Sichuan Univ Chengdu China

The effect of quenching temperature on the recovery stress of Fe 18Mn 5Si 8Cr 4ni shape memory alloy has been studied. The results show that both the maximum recovery stress σ h in heating and the recovery stress σ c at room temperature after heating increased as increasing quenching temperature increased, both σ h and σ c reached maximum at 650℃, and then decreased rapidly with the further increase in quenching temperature,but the descent degree of σ c was far bigger than that of σ h; When the quenching temperature is higher than 850℃, the further increase in quenching temperature had little effect on them; At random quenching temperature, σ c was far bigger than σ h.

关键词： shape memory alloy quenching recovery stress

Deformation mechanism at impact test of Al-11% Si alloy processed by equal-channel angular pressing with rotary die

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中国有色金属学会会刊：英文版 2007年第1期17卷 104-109页

作者：马爱斌 y. nISHIDA 江静华 n. SAITO I. SHIGEMATSU A. WATAZU Department of Materials Science and Engineering Hohai University national Institute of Advanced Industrial Science and Technology ShimoshidamiMoriyama-ku

Al-11%Si(mass fraction)alloy was transformed into a ductile material by equal-channel angular pressing(ECAP)with a rotary *** mechanisms at impact test,slip deformation by dislocation motion and grain boundary sliding,were *** ultrafine grains with modified grain boundaries and the high content of fine particles(necessary for attaining high absorbed *** results contradict the condition of slip deformation by dislocation motion and coincide with that of grain boundary *** fine zigzag lines like a mosaic were observed on the side surface of the tested *** observed lines may show grain boundaries appeared by the sliding of grains.

关键词：铝合金变形行为微观结构晶界滑动