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thermally Radiative Viscous Fluid Flow Over Curved Moving Surface in Darcy-Forchheimer Porous Space

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Communications in theoretical Physics 2019年第3期71卷 259-266页

作者： A.Rauf z.Abbas S.A.Shehzad t.Mushtaq Department of Mathematics The Islamia University of Bahawalpur Department of Mathematics COMSATS University Islamabad

A numerical analysis is developed for incompressible hydromagnetic viscous fluid passed through a curved stretching surface. Fluid saturated by porous space is bounded by curved surface. term of porous medium is characterized by implementation of Darcy-Forchheimer theory. Adequate similarity variables are implemented to develop a system of non-linear ordinary differential system of equations, which govern the flow behavior. the impact of radiation constraint and Eckert number is incorporated in the energy equation. Numerical scheme based on RKF45 technique is implemented to solve the derived flow model. Prescribed heat flux(PHF) and prescribed surface temperature(PSt) boundary conditions are utilized on temperature with Prescribed Surface Concentration(PSC) and Prescribed Mass Flux(PMF)on concentration. Flow behavior is discussed for both the slip and no-slip conditions. Dimensionless physical quantities are presented through graphs and tables.

关键词： viscous fluid porous medium curved stretching sheet radiation Joule heating

Growth and Physical Properties of CdS/tiO_2 Bilayer by Plasma-Based Method

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Chinese Physics Letters 2018年第3期35卷 39-42页

作者： t.Hoseinzadeh M.Ghoranneviss E.Akbarnejad z.Ghorannevis Department of Physics Science and Research Branch Islamic Azad University Department of Physics Karaj Branch Islamic Azad University

the titanium oxide （tiO2） nanotubes have attracted attention for their use in dye-sensitized solar cells as photoanode. In this study semiconducting cadmium sulfide （CdS） nanoparticles arc grown on top opened tiO2 nanotubes arrays by radio-frequency magnetron sputtering. X-ray diffraction, scanning electron mieroscopy, transmission electron microscopy and diffuse reflection spectra are used to study structural, morphological and optical properties of the CdS/tiO2 bilayer.

关键词： CdS tiO Growth and Physical Properties of CdS/tiO2 Bilayer by Plasma-Based Method

Finite element simulations on the mechanical properties of MHS materials

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Acta Mechanica Sinica 2007年第1期23卷 65-75页

作者： z. Y. Gao t. X. Yu D. Karagiozova Department of Mechanical Engineering Hong Kong University of Science &Technology Clear Water Bay Kowloon Hong Kong China Institute of Mechanics Bulgarian Academy of Sciences Acad. G. Bonchev Street Block 4 Sofia 1113 Bulgaria

Finite element simulations are carried out to examine the mechanical behavior of the metallic hollow sphere （MHS） material during their large plastic deformation and to estimate the energy absorbing capacity of these materials under uniaxial compression. A simplified model is proposed from experimental observations to describe the connection between the neighboring spheres, which greatly improves the computation efficiency. the effects of the governing physical and geometrical parameters are evaluated; whilst a special attention is paid to the plateau stress, which is directly related to the energy absorbing capacity. Finally, the empirical functions of the relative material density are proposed for the elastic modulus, yield strength and plateau stress for FCC packing arrangement of hollow spheres, showing a good agreement with the experimental results obtained in our previous study.

关键词： Cellular material Hollow sphere Large plastic deformation Numerical simulation FEM

Structural and mechanical properties of Al–C–N films deposited at room temperature by plasma focus device

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Chinese Physics B 2016年第7期25卷 299-304页

作者： z A Umar R Ahmad R S Rawat M A Baig J Siddiqui t Hussain National Centre for Physics Quaid-i-Azam University Campus Department of Physics GC University NSSE National Institute of Education Nanyang Technological University Centre for Advanced Studies in Physics GC University

the Al–C–N films are deposited on Si substrates by using a dense plasma focus（DPF） device with aluminum fitted central electrode（anode） and by operating the device with CH_4/N_2 gas admixture ratio of 1：1. XRD results verify the crystalline Al N（111） and Al_3CON（110） phase formation of the films deposited using multiple shots. the elemental compositions as well as chemical states of the deposited Al–C–N films are studied using XPS analysis, which affirm Al–N, C–C, and C–N bonding. the FESEM analysis reveals that the deposited films are composed of nanoparticles and nanoparticle agglomerates. the size of the agglomerates increases at a higher number of focus deposition shots for multiple shot depositions. Nanoindentation results reveal the variation in mechanical properties（nanohardness and elastic modulus）of Al–C–N films deposited with multiple shots. the highest values of nanohardness and elastic modulus are found to be about 11 and 185 GPa, respectively, for the film deposited with 30 focus deposition shots. the mechanical properties of the films deposited using multiple shots are related to the Al content and C–N bonding.

关键词： dense plasma focus XPS field emission scanning electron microscope elastic modulus

Stretching a Curved Surface in a Viscous Fluid

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Chinese Physics Letters 2010年第2期27卷 149-152页

作者： M. Sajid N. Ali t. Javed z. Abbas theoretical Plasma Physics Division PINSTECH P.O. Nilore Islamabad 44000 Pakistan Faculty of Basic and Applied Sciences International Islamic University Islamabad 44000 Pakistan

this work is concerned with the viscous flow due to a curved stretching sheet. the similarity solution of the problem is obtained numerically by a shooting method using the Runge-Kutta algorithm. the physical quantities of interest like the fluid velocity and skin friction coefficient are obtained and discussed under the influence of dimensionless curvature. It is evident from the results that dimensionless curvature causes an increase in boundary layer thickness and a decrease in the skin friction coefficient.

关键词： Fluid dynamics Mathematical physics

Numerical simulation of chemically reactive Powell-Eyring liquid flow with double diffusive Cattaneo-Christov heat and mass flux theories

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Applied Mathematics and Mechanics(English Edition) 2018年第4期39卷 467-476页

作者： A.RAUF z.ABBAS S.A.SHEHzAD A.ALSAEDI t.HAYAt Department of Mathematics The Islamia University of Bahawalpur Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics Faculty of Science King Abdulaziz University Department of Mathematics Quaid-i-Azam University

A numerical study is reported for two-dimensional flow of an incompressible Powell-Eyring fluid by stretching the surface with the Cattaneo-Christov model of heat diffusion. Impacts of heat generation/absorption and destructive/generative chemical reactions are considered. Use of proper variables leads to a system of non-linear dimensionless expressions. Velocity, temperature and concentration profiles are achieved through a finite difference based algorithm with a successive over-relaxation(SOR) method. Emerging dimensionless quantities are described with graphs and tables. the temperature and concentration profiles decay due to enhancement in fluid parameters and Deborah numbers.

关键词： Powell-Eyring fluid Cattaneo-Christov model chemical reaction finite difference

An Analysis of Peristaltic Flow of a Micropolar Fluid in a Curved Channel

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Chinese Physics Letters 2011年第1期28卷 138-141页

作者： N. Ali M. Sajid t. ,laved z. Abbas Department of Mathematics International Islamic University Islamabad Paksitan theoretical Plasma Physics Division PINSTECH P.O. Nilore Islamabad Pakistan

We analyze the two-dimensional peristaltic flow of a micropolar fluid in a curved channel. Long wavelength and low Reynolds number assumptions are used in deriving the governing equations. A shooting method with fourth-order Runge-Kutta algorithm is employed to solve the equations. the influence of dimensionless curvature radius on pumping and trapping phenomena is discussed with the help of graphical results. It is seen that the pressure rise per wavelength in the pumping region increases with an increase in the curvature of the channel. Moreover the symmetry of the trapped bolus destroys in going from strMg＇ht to curved channel.

关键词： Fluid dynamics

PREPARAtION OF MESOPOROUS CARBON BY CARBON DIOXIDE ACtIVAtION WItH CAtALYSt

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 67-72页

作者： W.z. Shen A.H. Lu J.t. zheng Inst. of Coal Chem. Chinese Acad. of Sci. Taiyuan 030001 China

A mesoporous activated carbon (AC) can be successfully prepared by catalytic activation with carbon dioxide. For iron oxide as catalyst, there were two regions of mesopore size distribution, i.e. 2-5nm and 30-70nm. When copper oxide or magnesium oxide coexisted with iron oxide as composite catalyst, the content of pores with sizes of 2-5nm was decreased, while the pores with 30-70nm were increased significantly. For comparison, AC reactivated by carbon dioxide directly was also investigated. It was shown that the size of mesopores of the resulting AC concentrated in 2-5nm with less volume. the adsorption of Congo red was tested to evaluate the property of the result-ing AC. Furthermore, the factors affecting pore size distribution and the possibility of mesopore formation were discussed.

关键词： activated carbon mesopore. catalytic activation

Stagnation-point flow of couple stress fluid with melting heat transfer

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 167-176页

作者： t.HAYAt M.MUStAFA z.IQBAL A.ALSAEDI Department of Mathematics Quaid-i-Azam University Department of Mathematics Faculty of ScienceKing Abdulaziz University Research Centre for Modeling and Simulation (RCMS) National University of Sciences and Technology (NUST)

Melting heat transfer in the boundary layer flow of a couple stress fluid over a stretching surface is investigated. the developed differential equations are solved for homotopic solutions. It is observed that the velocity and the boundary layer thickness are decreasing functions of the couple stress fluid parameter. However, the temperature and surface heat transfer increase when the values of the couple stress fluid parameter increase. the velocity and temperature fields increase with an increase in the melting process of the stretching sheet.

关键词： couple stress fluid melting heat transfer stagnation-point flow series solution