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Partial slip effect on non-aligned stagnation point nanofluid over a stretching convective surface

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Chinese Physics B 2015年第1期24卷 369-376页

作者： S.nadeem Rashid Mehmood Noreen Sher Akbar Department of Mathematics Quaid-i-Azam University 45320Islamabad 44000Pakistan DBS&H CEMENational University of Sciences and TechnologyIslamabadPakistan

The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip. Two types of base fluids namely water and kerosene are selected with Cu nanoparticles. The governing physical problem is presented and transformed into a system of coupled nonlinear differential equations using suitable similarity transformations. These equations are then solved numerically using midpoint integration scheme along with Richardson extrapolation via Maple. Impact of relevant physical parameters on the dimensionless velocity and temperature profiles are portrayed through graphs. Physical quantities such as local skin frictions co-efficient and Nusselt numbers are *** is detected from numerical computations that kerosene-based nano fluids have better heat transfer capability compared with water-based nanofluids. Moreover it is found that water-based nanofluids offer less resistance in terms of skin friction than kerosene-based fluid. In order to authenticate our present study, the calculated results are compared with the prevailing literature and a considerable agreement is perceived for the limiting case.

关键词： partial slip non-aligned stagnation point nanofluid stretching convective surface

Numerical computations of magnetohydrodynamic mixed convective flow of Casson nanofluid in an open-ended cavity formed by earthquake-induced faults

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Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2215-2230页

作者： M.IBTESAM S.nadeem J.ALZABUT Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Mathematics and Sciences Prince Sultan UniversityRiyadh 11586Saudi Arabia Department of Mathematics Wenzhou UniversityWenzhou 325035Zhejiang ProvinceChina Department of Industrial Engineering OSTIM Technical UniversityAnkara 06374Turkiye

The numerical computations for the magnetohydrodynamic(MHD) mixed convective flow of a non-Newtonian Casson nanofluid(Cu/H2O) within an open-ended cavity formed by earthquake-induced faults are analyzed, aiming to investigate the fluid dynamics and convection processes of geothermal systems. Such cavities, typically found in energy reservoirs, are primarily caused by tensional fault zones formed due to the accumulated energy from the disintegration of radioactive materials. These cavities play a crucial role in energy transmission, particularly in the form of heat. The focus of this paper is on the laminar, steady, and incompressible fluid flow. An inclined magnetic field is applied with an angle of inclination z = 30°. Additionally, a heated material with two vertical corrugated walls is placed at the center of the cavity. The governing nonlinear partial differential equations(PDEs) are transformed into the equations with a nondimensional form. The Galerkin finite element method(FEM) is implemented to solve the dimensionless equations. The impacts of key variables, including the Reynolds number Re, the volume fraction(0.01≤ φ_(p)≤0.05), the Hartmann number Ha, and the Casson parameter(0.5≤γ≤1.0), on the velocity and temperature distributions are studied. The analysis of the fluid flow and the heat transfer rate is conducted. The results indicate that the velocity increases as the volume fraction and the Reynolds number ***, the heat transfer rate rises with the Reynolds number and the volume fraction,while decreases with the higher Hartmann number. The Nusselt number increases with the volume fraction and the Reynolds number but decreases with the Hartmann number.

关键词： nanofluid magnetohydrodynamic(MHD) Casson fluid mixed convection finite element method(FEM)

Robust and Efficient Data Transmission over Noisy Communication Channels Using Stacked and Denoising Autoencoders

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China Communications 2019年第8期16卷 82-92页

作者： Faisal nadeem Khan Alan Pak Tao Lau Department of Electrical Engineering The Hong Kong Polytechnic University

We study the effects of quantization and additive white Gaussian noise(AWGN) in transmitting latent representations of images over a noisy communication channel. The latent representations are obtained using autoencoders(AEs). We analyze image reconstruction and classification performance for different channel noise powers, latent vector sizes, and number of quantization bits used for the latent variables as well as AEs’ parameters. The results show that the digital transmission of latent representations using conventional AEs alone is extremely vulnerable to channel noise and quantization effects. We then propose a combination of basic AE and a denoising autoencoder(DAE) to denoise the corrupted latent vectors at the receiver. This approach demonstrates robustness against channel noise and quantization effects and enables a significant improvement in image reconstruction and classification performance particularly in adverse scenarios with high noise powers and significant quantization effects.

关键词： communication channels data compression deep learning autoencoders denoising autoencoders

Analytical Treatment of an Oldroyd 8-constant Fluid Between Coaxial Cylinders with Variable Viscosity

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Communications in Theoretical Physics 2011年第11期56卷 933-938页

作者： Muhammad Yousaf Malik Azad Hussain Sohail nadeem Department of Mathematics Quaid-i-Azam University

The flow of an Oldroyd 8-constant fluid between coaxial cylinders with variable viscosity is *** heat transfer analysis is also taken into *** analytical solution of the non-linear problem is obtained usinghomotopy an... 详细信息

关键词： variable viscosity analytical solution heat transfer

The Mathematical Analysis for Peristaltic Flow of Hyperbolic Tangent Fluid in a Curved Channel

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Communications in Theoretical Physics 2013年第6期59卷 729-736页

作者： S.nadeem E.N.Maraj Department of Mathematics Quaid-i-Azam University

In the present paper, we have investigated the peristaltic flow of hyperbolic tangent fluid in a curved channel. The governing equations of hyperbolic tangent fluid model for curved channel are derived including the effects of curvature. The highly nonlinear partial differential equations are simplified by using the wave frame transformation,long wave length and low Reynolds number assumptions. The reduced nonlinear partial differential equation is solved analytically with the help of homotopy perturbation method (HPM). The physical features of pertinent parameters have been discussed by plotting the graphs of pressure rise and stream functions.

关键词： tangent hyperbolic fluid curved channel peristaltic flow HPM

Suppression of methane formation during Fisher-Tropsch synthesis using manganese-cobalt oxide supported on H-5A zeolite as a catalyst

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Journal of Natural Gas Chemistry 2009年第2期18卷 187-190页

作者： Syed Tajammul Hussain Muhammad Mazhar Muhammad Arif nadeem National Centre for Physics Quaid-i-Azam UniversityIslamabad 43520 Pakistan Department of Chemistry Quaid-i-Azam UniversityIslamabad 43520 Pakistan

In Fischer-Tropsch synthesis reaction, methane formation is one of the side reactions which must be suppressed in order to get better catalytic selectivity for light olefins. In the present study, we have modified cobalt based Fischer-Tropsch catalyst and developed a process to minimize methane production, consequently to produce maximum yield of light olefins. Manganese-cobalt oxide supported on H-5A zeolite catalyst was synthesized using modified H-5A zeolite, to increase its surface acid sites. Increased acidity of zeolite plays a major part in the suppression of methane formation during the Fischer-Tropsch reaction. The modified zeolite results in the electronic modification of catalyst surface by creating new active catalytic sites. The results are compared with other supported catalysts along with unmodified zeolite. Appreciable reduction in methane formation is achieved on modified zeolite supported catalyst in comparison with unsupported catalyst.

关键词： methane formation Fisher-Tropsch synthesis manganese cobalt suppression

Heat transfer analysis of Williamson fluid over exponentially stretching surface

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Applied Mathematics and Mechanics(English Edition) 2014年第4期35卷 489-502页

作者： S.nadeem S.T.HUSSAIN Department of Mathematics Quaid-i-Azam University

This study explores the effects of heat transfer on the Williamson fluid over a porous exponentially stretching surface. The boundary layer equations of the Williamson fluid model for two dimensional flow with heat transfer are presented. Two cases of heat transfer are considered, i.e., the prescribed exponential order surface temperature （PEST） case and the prescribed exponential order heat flux （PEHF） case. The highly nonlinear partial differential equations are simplified with suitable similar and non-similar variables, and finally are solved analytically with the help of the optimal homotopy analysis method （OHAM）. The optimal convergence control parameters are obtained, and the physical fea- tures of the flow parameters are analyzed through graphs and tables. The skin friction and wall temperature gradient are calculated.

关键词： optimal homotopy analysis method (OHAM) Williamson fluid expo-nential stretching permeable wall heat transfer prescribed exponential order surfacetemperature (PEST) prescribed exponential order heat flux (PEHF)

Flow of a Jeffery-Six Constant Fluid Between Coaxial Cylinders with Heat Transfer Analysis

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Communications in Theoretical Physics 2011年第8期56卷 345-351页

作者： Muhammad Yousaf Malik Azad Hussain Sohail nadeem Department of Mathematics Quaid-i-Azam University

In the present investigation we have discussed the flow of a Jeffrey-six constant incompressible fluid between two infinite coaxial cylinders in the presence of heat transfer analysis. The governing equations of Jeffrey-six constant fluid along with energy equation have been derived in cylindrical coordinates. The highly nonlinear equations are simplified with the help of non-dimensional parameters and then solved analytically with the help of homotopy analysis method （HAM） for two fundamental flows namely Couette and Generalized Couette flow. The effects of emerging parameters are discussed through graphs. The convergence of the HAM solution has been discussed by plotting h-curves.

关键词： Jeffery-six constant fluid coaxial cylinders heat transfer analysis HAM solutions

Effects of induced magnetic field on peristaltic flow of Johnson-Segalman fluid in a vertical symmetric channel

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Applied Mathematics and Mechanics(English Edition) 2010年第8期31卷 969-978页

作者： S.nadeem N.S.AKBAR Department of Mathematics Quaid-i-Azam University

In this paper, the influence of heat transfer and induced magnetic field on peristaltic flow of a Johnson-Segalman fluid is studied. The purpose of the present investigation is to study the effects of induced magnetic field on the peristaltic flow of non-Newtonian fluid. The two-dimensional equations of a Johnson-Segalman fluid are simplified by assuming a long wavelength and a low Reynolds number. The obtained equations are solved for the stream function, magnetic force function, and axial pressure gradient by using a regular perturbation method. The expressions for the pressure rise, temperature, induced magnetic field, pressure gradient, and stream function are sketched and interpreted for various embedded parameters.

关键词： induced magnetic field vertical symmetric channel Johnson-Segalman fluid magnetohydrodynamics (MHD)