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1

Effects of variable fluid properties and mixed convection on biomagnetic fluid flow and heat transfer over a stretching sheet in the presence of magnetic dipole

Murtaza M. G., Alam Jahangir, Tzirtzilakis E. E., Shamshuddin Md., Ferdows M.

Journal of Power Technologies

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2023

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Vol. 103, nr 4

193--208

EN

This investigations covers the numerical analysis of a steady biomagnetic fluid flow (BFD) that passed through a two dimensional stretching sheet under the influence of magnetic dipole. The effect of fluid variable viscosity and thermal conductivity are also taken into consideration as assumed to vary as linear function of temperature. Our model mathematically formulated for BFD namely blood which consist of principles of magnetohydrodynamic (MHD) and ferrohydrodynamic (FHD), where blood treated as an electrically conducting fluid as well as polarization. Using similarity transformations, the governing system of partial differential equations are transferred into system of ordinary differential equations (ODE). The resulting coupled non linear ODE is numerically solved by employing bvp4c function technique available in MATLAB software. The effects of pertinent parameters namely ferromagnetic interaction parameter, magnetic field parameter, mixed convection parameter, viscosity variation parameter, Prandtl number, thermal conductivity parameter etc are plotted and discussed adequately for velocity and temperature profile as well as skin friction coefficient and rate of heat transfer. The results revels that velocity profile decreases as enhanced values of ferromagnetic number whereas temperature profile increased. Also found that skin friction coefficient reduces and rate of heat transfer increases by increasing values of thermal conductivity parameter and viscosity variation parameter. For numerical validation a comparisons has been made for some specific values with previous investigators. We hope that the present analysis will present in bio-medical and bio-engineering sciences.

2

A duality of biomagnetic fluid flow and heat transfer over a quadratic stretched sheet

Murtaza M. G., Tzirtzilakis E. E., Ferdows Mohammad

Journal of Power Technologies

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2021

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Vol. 101, nr 3

154--162

EN

This paper investigates duality solutions of biomagnetic fluid flow and heat transfer over a permeable quadratically stretching /shrinking sheet in the presence of a magnetic dipole. The governing nonlinear partial differential equations are converted into a set of nonlinear ordinary differential equations with the help of suitable similarity transformations and then solved numerically by using the boundary value problem solver bvp4c built in MATLAB software. We examine the effects of a variety of pertinent parameters - the ferromagnetic parameter, suction parameter, stretching/shrinking parameter - on velocity and temperature profiles, as well as the skin friction coefficient and Nusselt number, which are presented graphically. Dual solutions exist for certain values of stretching/shrinking sheet and suction parameters. The skin friction coefficient data are evaluated and compared with previous published data and better agreement is achieved. Therefore, it can be said with confidence that our present analysis is accurate. It also shows that the ferromagnetic and stretched parameters result in reduced velocity and thereby influence the temperature profile.

3

Effect of thermal radiation on biomagnetic fluid flow and heat transfer over an unsteady stretching sheet

Alam Jahangir Md., Murtaza Ghulam Md., Tzirtzilakis Efstratios E., Ferdows Mohammad

Computer Assisted Methods in Engineering and Science

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2021

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Vol. 28, no. 2

81--104

EN

This study examines the influence of thermal radiation on biomagnetic fluid, namelyblood that passes through a two-dimensional stretching sheet in the presence of magneticdipole. This analysis is conducted to observe the behavior of blood flow for an unsteadycase, which will help in developing new solutions to treat diseases and disorders related tohuman body. Our model is namely biomagnetic fluid dynamics (BFD), which is consistentwith two principles: ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD), whereblood is treated as electrically conductive. It is assumed that the implemented magneticfield is sufficiently strong to saturate the ferrofluid, and the variation of magnetization withtemperature may be approximated with the aid of a function of temperature distinction.The governing partial differential equations (PDEs) converted into ordinary differentialequations (ODEs) using similarity transformation and numerical results are thus obtainedby using the bvp4c function technique in MATLAB software with considering applicableboundary conditions. With the help of graphs, we discuss the impact of various param-eters, namely radiation parameter, unsteady parameter, permeability parameter, suctionparameter, magnetic field parameter, ferromagnetic parameter, Prandtl number, velocityand thermal slip parameter on fluid (blood) flow and heat transfer in the boundary layer.The rate of heat transfer and skin friction coefficient is also computationally obtained forthe requirement of this study. The fluid velocity decreases with increasing values of themagnetic parameter, ferromagnetic interaction parameter, radiation parameter whereastemperature profile increases for the unsteady parameter, Prandtl number, and permeability parameter. From the analysis, it is also observed that the skin friction coefficientdecreases and the rate of heat transfer increases respectively with increasing values ofthe ferromagnetic interaction parameter. The most important part of the present analy-sis is that we neither neglect the magnetization nor electrical conductivity of the bloodthroughout this study. To make the results more feasible, they are compared with thedata previously published in the literature and found to be in good accuracy.

4

Analysis of the influence of ferromagnetic contaminations in plastics on the measurements of disturbances of magnetic field of the Earth

Wołoszyn M., Jakubiuk K., Flis M.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 5

224--227

EN

Plastics can be contaminated with small particles or filings with ferromagnetic properties. These contaminations cause significant disturbances in the magnetic field in the case of taking measurements of very low magnetic fields. The analysis of the influence of contaminated plastics on magnetic measurements is presented in this paper.

PL

Tworzywa sztuczne mogą być zanieczyszczone objętościowo lub powierzchniowo przez ferromagnetyczne wtrącenia o bardzo małych rozmiarach posiadające właściwości ferromagnetyczne. Wtrącenia te powodują istotne zaburzenia pola magnetycznego w przypadku pomiarów bardzo słabych pól magnetycznych. W pracy przedstawiono analizę wpływu zanieczyszczonych objętościowo tworzyw na wyniki pomiarów pola magnetycznego.

5

Pola elektromagnetyczne źródeł dipolowych

Miecznik J.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2011

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T. 37, z. 1

37-61

PL

Na podstawie wzorów Maxwella wyprowadzono funkcje, które spełniają równania pola elektrycznego i magnetycznego. W przypadku pól harmonicznie zmiennych w czasie są to tzw. równania falowe. Do różnorodnych zadań geofizycznych opartych na analizie zmiennych w czasie pól elektromagnetycznych wykorzystuje się funkcje potencjalne: potencjał wektorowy i skalarny, które spełniają również równanie falowe. Potencjały wektorowy i skalarny są związane z polem elektrycznym i magnetycznym odpowiednimi równaniami. Aby określić pole elektromagnetyczne w ośrodkach niejednorodnych, należy uwzględnić warunki graniczne, które muszą spełniać wektory pola elektrycznego i magnetycznego, oraz potencjał wektorowy. Podano związki analityczne dla składowych pola elektromagnetycznego w przypadku dipola elektrycznego i magnetycznego w jednorodnej przestrzeni i półprzestrzeni. Określono parametry realnych układów pomiarowych spełniających warunki dipola elektrycznego i magnetycznego. Scharakteryzowano tzw. strefę bliską i daleką pomiarów elektromagnetycznych i podano związki analityczne dla składowych pola w tych strefach. Scharakteryzowano również pole elektromagnetyczne dla źródeł wykorzystywanych w praktyce, a mianowicie dla nieskończenie długiego kabla i nieuziemionej pętli.

EN

Equations satisfied by vectors of electric and magnetic field were derived based on Maxwell's equations. In the case of time-dependent harmonic fields these are so called wave equations. Potential functions, i.e. vector potential and scalar potential, that also satisfy the wave equation were used. Vector and scalar potentials are related with electric and magnetic field by means of a number of equations. To determine the electromagnetic field in a non-homogeneous medium one should define the boundary conditions for vectors of electric and magnetic field and vector potential. The paper presents analytical formulae for EM field components for electric dipole and magnetic dipole in a homogeneous space and half-space. Parameters of real measurement arrays that fulfill conditions of electric dipole and magnetic dipole are given. So called near zone and far zone for EM survey are defined. EM field of infinitely long cable and ungrounded loop is characterized.