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Transient flow of magnetized maxwell nanofluid: Buongiorno model perspective of Cattaneo-Christov theory

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Applied mathematics and mechanics(English Edition) 2020年第4期41卷 655-666页

作者： m.khan A.AhmED J.AhmED Department of mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

The present research article is devoted to studying the characteristics of Cattaneo-Christov heat and mass fluxes in the maxwell nanofluid flow caused by a stretching sheet with the magnetic field *** maxwell nanofluid is investigated with the impact of the Lorentz force to examine the consequence of a magnetic field on the flow characteristics and the transport of *** heat and mass transport mechanisms in the current physical model are analyzed with the modified versions of Fourier’s and Fick’s laws,***,the well-known Buongiorno model for the nanofluids is first introduced together with the Cattaneo-Christov heat and mass fluxes during the transient motion of the maxwell *** governing partial differential equations(PDEs)for the flow and energy transport phenomena are obtained by using the maxwell model and the Cattaneo-Christov theory in addition to the laws of *** transformations are used to convert the PDEs into a system of nonlinear ordinary differential equations(ODEs).The homotopic solution methodology is applied to the nonlinear differential system for an analytic *** results for the time relaxation parameter in the flow,thermal energy,and mass transport equations are discussed *** is noted that higher values of the thermal and solutal relaxation time parameters in the Cattaneo-Christov heat and mass fluxes decline the thermal and concentration fields of the ***,larger values of the thermophoretic force enhance the heat and mass transport in the ***,the Brownian motion of the nanoparticles declines the concentration field and increases the temperature *** validation of the results is assured with the help of numerical tabular data for the surface velocity gradient.

关键词： transient flow Cattaneo-Christov theory maxwell nanofluid Buongiorno model homotopy analysis method (HAm) solution

Boundary layer flow of maxwell fluid due to torsional motion of cylinder: modeling and simulation

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Applied mathematics and mechanics(English Edition) 2020年第4期41卷 667-680页

作者： m.khan A.AhmED J.AhmED Department of mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

This paper investigates the boundary layer flow of the maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic *** constitutive flow equations for the current physical problem are modeled and analyzed for the first time in the *** torsional motion of the cylinder is considered with the constant azimuthal velocity *** partial differential equations(PDEs)governing the torsional motion of the maxwell fluid together with energy transport are simplified with the boundary layer *** current analysis is valid only for a certain range of the positive Reynolds ***,for very large Reynolds numbers,the flow becomes ***,the governing similarity equations are simplified through suitable transformations for the analysis of the large Reynolds *** numerical simulations for the flow,heat,and mass transport phenomena are carried out in view of the bvp4c scheme in *** outcomes reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds numbers and the flow penetrates shallower into the free stream *** is also noted that the phenomenon of stress relaxation,described by the Deborah number,causes to decline the flow fields and enhance the thermal and solutal energy transport during the fluid *** penetration depth decreases for the transport of heat and mass in the fluid with the higher Reynolds *** excellent validation of the numerical results is assured through tabular data with the existing literature.

关键词： torsional motion maxwell fluid magnetic field stretchable rotating cylinder bvp4c scheme

Exact solutions of mHD second Stokes flow of generalized Burgers fluid

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Applied mathematics and mechanics(English Edition) 2015年第2期36卷 211-224页

作者： m.khan R.mALIK A.ANJUm Department of mathematics Quaid-i-Azam University

This work concerns with the exact solutions of magnetohydrodynamic（mHD）flow of generalized Burgers fluid describing the second Stokes problem. The modified Darcy law is taken into account. The related velocity distribution and shear stress are expressed as a combination of steady-state and transient solutions computed by means of integral transformations. The effects of various parameters on the flow field are investigated. The mHD flow results in reduction of velocity distribution and associated thickness of the boundary layer.

关键词： generalized Burgers fluid magnetohydrodynamic(mHD) flow porous medium exact solution

Aqueous solution of basic fuchsin as food irradiation dosimeter

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Nuclear Science and Techniques 2007年第3期18卷 141-144页

作者： Hasan m.khan shagufta NAZ radiation Chemistry Laboratory National Centre of Excellence in Physical ChemistryUniversity of PeshawarPeshawar 25120 Pakistan

Dosimetric characterization of aqueous solution of basic fuchsin was studied spectrophotometrically for possible application in the low-dose food irradiation dosimetry. Absorption spectra of unirradiated and irradiated solu- tions were determined and the decrease in absorbance with the dose was noted down. radiation-induced bleaching of the dye was measured at wavelengths of maximum absorption λmax (540nm) as well as 510nm and 460 nm. At all these wavelengths, the decrease in absorbance of the dosimeter was linear with respect to the absorbed dose from 50 Gy to 600 Gy. The stability of dosimetric solution during post-irradiation storage in the dark at room temperature showed that after initial bleaching during first ten to twenty days, the response was almost stable for about 34 days. The study on the effect of different light and temperature conditions also showed that the response gradually decreased during the storage period of 34 days, which shows that basic fuchsin dye is photosensitive as well as thermally sensitive.

关键词：水溶液食物辐射计量品红

Chemically reactive and radiative von Kármán swirling flow due to a rotating disk

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Applied mathematics and mechanics(English Edition) 2018年第9期39卷 1295-1310页

作者： m.khan J.AhmED L.AhmAD Department of mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan Department of mathematics Shaheed Benazir Bhutto UniversitySheringal Upper Dir 18000Pakistan

A new mathematical model is presented to study the heat and mass transfer characteristics of magnetohydrodynamic(mHD) maxwell fluid flow over a convectively heated stretchable rotating disk. To regulate the fluid temperature at the surface, a simple isothermal model of homogeneous-heterogeneous reactions is employed. The impact of nonlinear thermal radiative heat flux on thermal transport features is studied. The transformed nonlinear system of ordinary differential equations is solved numerically with an efficient method, namely, the Runge-Kutta-Felberg fourth-order and fifth-order(RKF45)integration scheme using the mAPLE software. Achieved results are validated with previous studies in an excellent way. major outcomes reveal that the magnetic flux reduces the velocity components in the radial, angular, and axial directions, and enhances the fluid temperature. Also, the presence of radiative heat flux is to raise the temperature of fluid. Further, the strength of homogeneous-heterogeneous reactions is useful to diminish the concentration of reaction.

关键词： rotating stretchable disk magnetic field nonlinear radiative heat flux homogeneous-heterogeneous chemical reaction

Slip effects on shearing flows in a porous medium

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Acta mechanica Sinica 2008年第1期24卷 51-59页

作者： m.khan T.Hayat Y.Wang Department of mathematics Quaid-i-Azam University Islamabad 44000 Pakistan Chair of Fluid Dynamics Department of Mechanical Engineering Darmstadt University of TechnologyHochschulstrasse 164289 Darmstadt Germany

This paper deals with the magnetohydrodynamic （mHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.

关键词： Porous medium. magnetohydrodynamic flow Slip effect

Von Kármán rotating flow of maxwell nanofluids featuring the Cattaneo-Christov theory with a Buongiorno model

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Applied mathematics and mechanics(English Edition) 2020年第8期41卷 1195-1208页

作者： A.AhmED m.khan J.AhmED A.HAFEEZ Department of mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan

This research paper analyzes the transport of thermal and solutal energy in the maxwell nanofluid flow induced above the disk which is rotating with a constant angular *** significant features of thermal and solutal relaxation times of fluids are studied with a Cattaneo-Christov double diffusion theory rather than the classical Fourier’s and Fick’s laws.A novel idea of a Buongiorno nanofluid model together with the Cattaneo-Christov theory is introduced for the first time for the maxwell fluid flow over a rotating ***,the thermal and solutal distributions are controlled with the impacts of heat source and chemical *** classical von Karman similarities are used to acquire the non-linear system of ordinary differential equations(ODEs).The analytical series solution to the governing ODEs is obtained with the well-known homotopy analysis method(HAm).The validation of results is provided with the published results by the comparison *** graphically presented outcomes for the physical problem reveal that the higher values of the stretching strength parameter enhance the radial velocity and decline the circumferential *** increasing trend is noted for the axial velocity profile in the downward direction with the higher values of the stretching strength *** higher values of the relaxation time parameters in the Cattaneo-Christov theory decrease the thermal and solutal energy transport in the flow of maxwell *** higher rate of the heat transport is observed in the case of a larger thermophoretic force.

关键词： maxwell fluid nanoparticle Cattaneo-Christov theory rotating disk homotopy analysis method(HAm)

magnetohydrodynamic Stagnation Point Flow of a maxwell Nanofluid with Variable Conductivity

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Communications in Theoretical Physics 2019年第12期71卷 1493-1500页

作者： m.Irfan m.khan W.A.khan m.Alghamdi Department of mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan School of mathematics and Statistics Beijing Institute of TechnologyBeijing 100081China Department of mathematics Faculty of ScienceKing Khalid UniversityAbha 61413Kingdom of Saudi Arabia

This article reports the simultaneous properties of variable conductivity and chemical reaction in stagnation point flow of magneto maxwell *** Buongiorno’s theory has been established to picture the inducement of Brownian and thermophrotic diffusions ***,the aspect of heat sink/source is *** homotopic analysis method(HAm)has been worked out for the solution of nonlinear *** behavior of inferential variables on the velocity,temperature,concentration and local Nusselt number for maxwell nanofluid are sketched and *** attained outcomes specify that both the temperature and concentration of maxwell fluid display analogous behavior,while the depiction of Brownian motion is quite conflicting on both temperature and concentration *** is further noted that the influence of variable thermal conductivity on temperature field is similar to that of Brownian motion ***,for the confirmation of our study comparison tables are reported.

关键词： maxwell nanofluid stagnation point flow magnetohydrodynamic(mHD) variable conductivity chemical reaction

identification of radiation treatment of wheat (Triticum aestivum.L) and rice (Oryza sativa.L) samples using thermoluminescence of contaminating minerals

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Nuclear Science and Techniques 2007年第1期18卷 26-29页

作者： Hasan m.khan Ijaz A.BHATTI radiation Chemistry Laboratory NCE Physical ChemistryUniversity of PeshawarPeshawarPakistan Department of Chemistry University of AgricultureFaisalabadPakistan

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of *** of the rapid commercialization of irradiated foods throughout the world,compliance of different regulations relating to use of technology in different countries and demand of consum- ers for clear labelling of irradiated foods,there is need for the development of analytical methods to detect radiation treatment of *** several methods studied so far,thermoluminescence (TL) is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust *** this study,the irradiated and unirradiated wheat and rice samples were analyzed using the TL *** samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture (NIFA),*** mineral contaminants were isolated by jet water,ultrasonic treatment,and density *** glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50—500℃using a TL ***,the glow curves for irradiated samples showed much higher TL intensities (TL_1) than the unirradiated *** results were normalized by re-irradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves (TL_2).The ratio of the area of first glow curve to that of second glow curve (TL_1/TL_2) was calcu- lated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated ***,the shapes of the glow curves for irradiated and unirradiated samples were also *** the ba- sis of these results (comparison of TL-intensities,TL_1/TL_2 ratios and shapes of the glow curves),all the irradiated and unirradiated samples of wheat and rice were un

关键词：小麦水稻辐射处理沾染矿物质食品检验热致发光