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Analysis of a permeable interface crack in elastic dielectric/piezoelectric bimaterials

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Acta Mechanica Sinica 2007年第6期23卷 681-687页

作者： Qun Li Yiheng Chen School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China School of Aerospace Xi’an Jiaotong University Xi’an China

A permeable interface crack between elasticdielectric material and piezoelectric material is studied basedon the extended Stroh’s formalism.Motivated by strong engi-neering demands to design new composite materials,theauthors perform numerical analysis of interface crack tip sin-gularities and the crack tip energy release rates for 35 typesof dissimilar bimaterials,respectively,which are constructedby five kinds of elastic dielectric materials:Epoxy,Poly-mer,Al;O;.SiC,and Si;N;and seven kinds of practicalpiezoelectric ceramics:PZT-4,BaTiO;,PZT-5H,PZT-6B,PZT-7A,P-7,and PZT-PIC 151,respectively.The elasticdielectric material with much smaller permittivity than com-mercial piezoelectric ceramics is treated as a special trans-versely isotropic piezoelectric material with extremely smallpiezoelectricity.The present investigation shows that thestructure of the singular field near the permeable interfacecrack tip consists of three singularities:r;and r;,which is quite different from that in the impermeable inter-face crack.It can be concluded that different far field load-ing cases have significant influence on the near-tip fracturebehaviors of the permeable interface crack.Based on thepresent theoretical treatment and numerical analysis,the elec-tric field induced crack growth is well explained,which pro-vides a better understanding of the failure mechanism inducedfrom interface crack growth in elastic dielectric/piezoelectricbimaterials.

关键词： Elastic dielectric Piezoelectric permeable Interface crack Singularity Energy release rate

Numerical Study of Unsteady MHD Flow and Entropy Generation in a Rotating permeable Channel with Slip and Hall Effects

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Communications in Theoretical Physics 2018年第11期69卷 641-650页

作者： Z.H.Khan O.D.Makinde R.Ahmad W.A.Khan State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource & HydropowerSichuan University Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education Tsinghua University Faculty of Military Science Stellenbosch University School of Mathematics and Physics University of Queensland Faculty of Engineering Sciences GIK Institute of Engineering Sciences and Technology Department of Mechanical Engineering College of Engineering Prince Mohammad Bin Fahd University

This article investigates an unbiased analysis for the unsteady two-dimensional laminar flow of an incompressible, electrically and thermally conducting fluid across the space separated by two infinite rotating permeable walls.The influence of entropy generation, Hall and slip effects are considered within the flow analysis. The problem is modeled based on valid physical arguments and the unsteady system of dimensionless PDEs (partial differential equations) are solved with the help of Finite Difference Scheme. In the presence of pertinent parameters, the precise movement of the flow in terms of velocity, temperature, entropy generation rate, and Bejan numbers are presented graphically, which are parabolic in nature. Streamline profiles are also presented, which exemplify the accurate movement of the flow. The current study is one of the infrequent contributions to the existing literature as previous studies have not attempted to solve the system of high order non-linear PDEs for the unsteady flow with entropy generation and Hall effects in a permeable rotating channel. It is expected that the current analysis would provide a platform for solving the system of nonlinear PDEs of the other unexplored models that are associated to the two-dimensional unsteady flow in a rotating channel.

关键词： unsteady flow rotating permeable channel MHD slip hall effects entropy analysis finite difference method

Partial oxidation of methane to syngas in a mixed-conducting oxygen permeable membrane reactor

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Chinese Science Bulletin 2000年第3期45卷 224-226页

作者： Hui Dong Guoxing Xiong Zongping Shao Shenglin Liu Weishen Yang Chinese Acad Sci Dalian Inst Chem Phys State Key Lab Catalysis Dalian 116023 Peoples R China

Mixed-conducting oxygen permeable membranes represent a class of novel ceramic membranes, which exhibit mixed oxygen ionic and electronic conductivities. At high temperatures, oxygen can permeate through the membrane from the high to low oxygen pressure side under an oxygen concentration gradient. Theoretically, the permselectivity of oxygen is 100%. Recently, anovel mixed-conducting membrane-Ba0.5Sr0.5Coo.8Feo.2O3-δ has been developed, which showsextremely high oxygen permeability and promising stability. Furthermore, the reactor made with such membranes was successfully applied to the partial oxidation of methane to syngas reaction using air as the oxygen source, which realized the coupling of the separation of oxygen from air and the partial oxidation of membrane reaction in one process. At 850℃, methane conversion > 88%, CO selectivity >97% and oxygen permeation rate of about 7.8 mL/(cm2 ·min) were obtained.

关键词： mixed-conducting oxygen permeable membrane perovskite membrane reactor partial oxidation of methane catalysis in membrane reactor.

Hydrothermal fluid circulation in anisotropic permeable media associated with discrete fractures

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中国有色金属学会会刊：英文版 2000年第4期10卷 542-547页

作者：杨建文 University of Tasmania 澳大利亚

A proper form of the Rayleigh number, containing the geometric mean of the vertical and horizontal permeabilities was obtained. The critical value for the onset of stable convection was found. The results proved analytically and numerically that anisotropy in permeability resists the initiation of hydrothermal convection. The equivalence between homogeneously anisotropic media and multiply fractured media was also investigated. It was confirmed that multiply fractured models are comparable to anisotropic models as long as they have the same averaged horizontal or vertical permeabilities and other physical parameters.

关键词： hydrothermal fluid circulation anisotropic permeable media fractures

Mixed Convection MHD Flow of a Casson Nanofluid over a Nonlinear permeable Stretching Sheet with Viscous Dissipation

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Journal of Applied Mathematics and Physics 2015年第12期3卷 1580-1593页

作者： Prabhakar Besthapu Shanker Bandari Department of Mathematics Govt. Degree & P. G. College Peddapalli India Department of Mathematics Osmania University Hyderabad India

The present study deals with the mixed convection MHD flow of a Casson nanofluid over a nonlinear permeable stretching sheet with viscous dissipation. The governing partial differential equations are transformed into nonlinear coupled ordinary differential equations with the help of suitable similarity transformations. These equations were then solved numerically by using an implicit finite difference method known as Keller-Box method. The effects of various parameters such as magnetic parameter (M), Casson parameter (β), local Grashoff number (Gr), local modified Grashoff number (Gc), nonlinear parameter (n), Eckert number (Ec) on velocity, temperature and concentration were discussed and presented graphically. It is found that a larger value of Casson parameter leads to decrease the velocity and temperature. Increase in the local Grashoff number reduces the temperature. Nanoparticle concentration is decreased for the larger values of local Modified Grashoff number. The numerical values of skin friction, Nusselt number and Sherwood number are presented in tables.

关键词： MHD Nonlinear permeable Stretching Sheet Mixed Convection Casson Fluid

Turbulent-Induced Noise around a Circular Cylinder Using permeable FW-H Method

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Journal of Applied Mathematics and Physics 2015年第2期3卷 161-165页

作者： Woen-Sug Choi Suk-Yoon Hong Jee-Hun Song Hyun-Wung Kwon Chul-Min Jung Tae-Gyoung Kim Departmentof Naval Architecture and Ocean Engineering Seoul National University Seoul Republic of Korea Department of Naval Architecture and Ocean Engineering Chonnam National University Yeosu Republic of Korea Department of Naval Architecture and Ocean Engineering Koje College Koje Republic of Korea Advanced Naval Technology Center NSRDI Agency for Defense Development Chinhae Republic of Korea

Varieties of research on turbulent-induced noise are conducted with combinations of acoustic analogy methods and computational fluid dynamic methods to analyse efficiently and accurately. Application of FW-H acoustic analogy without turbulent noise is the most popular method due to its calculation cost. In this paper, turbulent-induced noise is predicted using RANS turbulence model and permeable FW-H method. For simplicity, noise from 2D cylinder is examined using three different methods: direct method of RANS, FW-H method without turbulent noise and permeable FW-H method which can take into account of turbulent-induced noise. Turbulent noise was well predicted using permeable FW-H method with same computational cost of original FW-H method. Also, ability of permeable FW-H method to predict highly accurate turbulent-induced noise by applying adequate permeable surface is presented. The procedure to predict turbulent- induced noise using permeable FW-H is established and its usability is shown.

关键词： Turbulent-Induced Noise Circular Cylinder Acoustic Analogy FW-H Method permeable FW-H Method

MHD Stagnation Point Flow and Heat Transfer over a permeable Surface

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Engineering（科研） 2013年第1期5卷 50-55页

作者： Santosh Chaudhary Pradeep Kumar Department of Mathematics Malaviya National Institute of Technology Jaipur Rajasthan India

The steady two-dimensional, laminar flow of a viscous, incompressible, electrically conducting fluid near a stagnation point with heat transfer over a permeable surface in the presence of a uniform magnetic field is considered. Taking suitable similarity variables, the governing boundary layer equations are transformed to ordinary differential equations and solved numerically by Shooting method. The effects of the suction parameter, the magnetic parameter, the Prandtl number and the Eckert number are studied on the velocity and temperature distributions.

关键词： MHD Stagnation Point Heat Transfer permeable Surface

Incorporation of zero valent iron into pelletized surfactant-modified zeolite as permeable barriers for groundwater remediation

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Global Geology 1998年第1期3卷 40-41页

Hydrogen peroxide mediates pro-inflammatory cell-to-cell signaling: a new therapeutic target for inflammation?

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Neural Regeneration Research 2019年第8期14卷 1430-1437页

作者： Dhanushka Gunawardena Ritesh Raju Gerald Münch Department of Pharmacology School of Medicine Western Sydney University

Nitric oxide is now universally recognized as an extracellular signaling molecule. Nitric oxide, produced in one cell, diffuses across the extracellular space and acts with targets in an adjoining cell. In this study, we present proof that hydrogen peroxide - like nitric oxide - acts as a true first (intercellular) messenger for a multitude of pro-inflammatory ligands. RAW 264.7 macrophages were activated with three different ligands, lipopolysaccharide, interferon-gamma or advanced glycation end products in the presence of increasing concentrations of (hydrogen peroxide scavenging) catalase. As inflammatory readouts, nitric oxide and tumor necrosis factor were determined. We hypothesize that hydrogen peroxide travels between cells propagating the signal, then a certain percentage of the readout should be inhibited by catalase in a concentration- dependent manner. The experiment showed concentration-dependent inhib让ion of nitric oxide and tumor necrosis factor-a production in response to all three ligands/ligand combinations (interferon-gamma, lipopolysaccharide, and chicken egg albumin-derived advanced glycation end product) in the presence of increasing concentration of catalase. For example, catalase inhibited 100% of nitric oxide and 40% of tumor necrosis factor-a production at its highest concentration. Our results suggest that hydrogen peroxide travels through cell membranes into the extracellular space and enters and activates ad;acent cells. Like rdtric oxide, we suggest that it is a ubiquitous first messenger, able to transmit cell-to-cell pro-inflammatory signals such as nitric oxide and tumor necrosis factor-a. In a therapeutic setting, our data suggest that compounds acting as hydrogen peroxide scavengers might not even need to enter the cell to act as anti-inflammatory drugs.

关键词： Inflammation glycation redox signaling cytokines anti-inflammatory drugs hydrogen peroxide membrane permeable lipopolysaccharide Interferon-gamma signaling