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Influence of magnetic field and Hall currents on blood flow through a stenotic artery

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Applied Mathematics and Mechanics(English Edition) 2008年第8期29卷 1093-1104页

作者： kh.s.mekheimer M.A.El Kot Department of Mathematics Faculty of ScienceAl-Azhar University Nasr City 11884CairoEgypt Department of Mathematics Faculty of EducationSuez Canal UniversitySuezEgypt

A micropolar model for blood simulating magnetohydrodynamic flow through a horizontally nonsymmetric but vertically symmetric artery with a mild stenosis is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the horizontal shape of the stenosis can easily be changed just by varying a parameter referred to as the shape parameter. Flow parameters, such as velocity, the resistance to flow （the resistance impedance）, the wall shear stress distribution in the stenotic region, and its magnitude at the maximum height of the stenosis （stenosis throat）, have been computed for different shape parameters, the Hartmann number and the Hall parameter. This shows that the resistance to flow decreases with the increasing values of the parameter determining the stenosis shape and the Hail parameter, while it increases with the increasing Hartmann number. The wall shear stress and the shearing stress on the wall at the maximum height of the stenosis possess an inverse characteristic to the resistance to flow with respect to any given value of the Hartmann number and the Hall parameter. Finally, the effect of the Hartmann number and the Hall parameter on the horizontal velocity is examined.

关键词： stenotic artery Hall currents blood flow

Couple stress fluid flow in a rotating channel with peristalsis

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Journal of Hydrodynamics 2018年第2期30卷 307-316页

作者： Y.Abd elmaboud sara I.Abdelsalam kh.s.mekheimer Mathematics Department Faculty of Science and Arts Khulais University Of Jeddah Mathematics Department Faculty of Science Al-Azhar University (Assiut Branch) Department of Mechanical Engineering University of CaliforniaRiverside USA Basic science Department Faculty of Engineering The British University in Egypt Mathematics Department Faculty of Science Al-Azhar University

This article describes a new model for obtaining closed-form semi-analytical solutions of peristaltic flow induced by sinusoidal wave trains propagating with constant speed on the walls of a two-dimensional rotating infinite channel. The channel rotates with a constant angular speed about the z-axis and is filled with couple stress fluid. The governing equations of the channel deformation and the flow rate inside the channel are derived using the lubrication theory approach. The resulting equations are solved, using the homotopy perturbation method（HPM）, for exact solutions to the longitudinal velocity distribution, pressure gradient, flow rate due to secondary velocity, and pressure rise per wavelength. The effect of various values of physical parameters, such as, Taylor＇s number and couple stress parameter, together with some interesting features of peristaltic flow are discussed through graphs. The trapping phenomenon is investigated for different values of parameters under consideration. It is shown that Taylor＇s number and the couple stress parameter have an increasing effect on the longitudinal velocity distribution till half of the channel, on the flow rate due to secondary velocity, and on the number of closed streamlines circulating the bolus.

关键词： Homotopy perturbation method (HPM) couple stress fluid rotating channel peristaltic transport

Effects of magnetic field,porosity,and wall properties for anisotropically elastic multi-stenosis arteries on blood flow characteristics

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Applied Mathematics and Mechanics(English Edition) 2011年第8期32卷 1047-1064页

作者： kh.s.mekheimer M.H.HAROUN M.A.ELKOT Department of Mathematics Faculty of science Al-Azhar University Department of Mathematics Faculty of Education Ain shams University Department of Mathematics Faculty of science suez Canal University

A mathematical model for blood flow through an elastic artery with multistenosis under the effect of a magnetic field in a porous medium is presented. The considered arterial segment is simulated by an anisotropically elastic cylindrical tube filled with a viscous incompressible electrically conducting fluid representing blood. An artery with mild local narrowing in its lumen forming a stenosis is analyzed. The effects of arterial wall parameters represent viscoelastic stresses along the longitudinal and circumferential directions T t and T θ , respectively. The degree of anisotropy of the vessel wall γ, total mass of the vessel, and surrounding tissues M and contributions of the viscous and elastic constraints to the total tethering C and K respectively on resistance impedance, wall shear stress distribution, and radial and axial velocities are illustrated. Also, the effects of the stenosis shape m, the constant of permeability κ, the Hartmann number Ha and the maximum height of the stenosis size δ on the fluid flow characteristics are investigated. The results show that the flow is appreciably influenced by surrounding connective tissues of the arterial wall motion, and the degree of anisotropy of the vessel wall plays an important role in determining the material of the artery. Further, the wall shear stress distribution increases with increasing T t and γ while decreases with increasing T θ , M, C, and K. Transmission of the wall shear stress distribution and resistance impedance at the wall surface through a tethered tube are substantially lower than those through a free tube, while the shearing stress distribution at the stenosis throat has inverse characteristic through totally tethered and free tubes. The trapping bolus increases in size toward the line center of the tube as the permeability constant κ increases and decreases with the Hartmann number Ha increased. Finally, the trapping bolus appears, gradually in the case of non-symmetric stenosis, and disap

关键词： stenosis degree of anisotropy free tube tethered tube trapping bolus

series solution of a natural convection flow for a Carreau fluid in a vertical channel with peristalsis

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Journal of Hydrodynamics 2015年第6期27卷 969-979页

作者： ABD ELMABOUD Y. mekheimer kh.s. MOHAMED Mohamed s. Mathematics Department Faculty of Science and ArtsKhulaisUniversity Of Jeddah Mathematics Department Faculty of ScienceAl-Azhar University(Assiut Branch) Mathematics Department Faculty of ScienceTaif University Hawia Mathematics Department Faculty of ScienceAl-Azhar University

An analysis has been achieved to study the natural convection of a non-Newtonian fluid （namely a Carreau fluid） in a vertical channel with rhythmically contracting walls. The Navier-stokes and the energy equations are reduced to a system of non- linear PDE by using the long wavelength approximation. The optimal homotopy analysis method （OHAM） is introduced to obtain the exact solutions for velocity and temperature fields. The convergence of the obtained OHAM solution is discussed explicitly. Numerical calculations are carried out for the pressure rise and the features of the flow and temperature characteristics are analyzed by plotting graphs and discussed in detail.

关键词： homotopy analysis method (HAM) peristaltic transport carreau fluid heat transfer natural convection flow

PARTICULATE sUsPENsION FLOW INDUCED BY sINUsOIDAL PERIsTALTIC WAVEs THROUGH ECCENTRIC CYLINDERs： THREAD ANNULAR

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International Journal of Biomathematics 2013年第4期6卷 113-137页

作者： kh. s. mekheimer Y. ABD ELMABOUD A. I. ABDELLATEEF Mathematics Department Faculty of Science Al-Azhar University Nasr City 11448 Cairo Egypt Mathematics Department Faculty of Science Tail University Hawia (888) Tail Saudi Arabia Mathematics Department Faculty of Science and Arts Khulais King Abdulaziz University (KAU) Saudi Arabia Mathematics Department Faculty of Science Al-Azhar University (Assiut Branch) Assiut Egypt Basic science Department Higher Institute of Engineering Shorouk City Cairo Egypt

This paper describes a new model for obtaining analytical solutions of peristaltic flow through eccentric annuli. A mathematical model of peristaltic pumping of a fluid mixture （as blood model） in a circular eccentric cylinders is presented and it is motivated due to the fact that thread injection is a promising method for placing medical implants within the human body with minimum surgical trauma. For the eccentric annuli, the inner cylinder is rigid and moving with a constant velocity V, and the outer one is hollow flexible cylinder that has a sinusoidal wave traveling down its wall. The coupled differential equations for both the fluid and the particle phases have been solved by using two methods and the expressions for the velocity distribution of fluid and particle phase, flow rate, pressure drop, friction forces at the inner and outer cylinders have been derived. The results obtained are discussed in brief. The significance of the particle concentration and the eccentricity parameter as well as the nature of the basic flow has been well explained.

关键词： Eccentric annulus flows particle fluid suspension peristalsis endoscope

Flexible impedance and capacitive tensile load sensor based on CNT composite

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Chinese Physics B 2016年第2期25卷 568-572页

作者： Zubair Ahmad kh s Karimov Farid Touati Department of Electrical Engineering College of Engineering Qatar University Doha 2713 Qatar Ghulam Ishaq khan Institute of Engineering sciences and Technology Topi District Swabi KPK 23640 Pakistan Center for Innovative Development of science and New Technologies Academy of Sciences Aini St. 299/2 Dushanbe 734063 Tajikistan

In this paper, the fabrication and investigation of flexible impedance and capacitive tensile load sensors based on carbon nanotube（CNT） composite are reported. On thin rubber substrates, CNTs are deposited from suspension in water and pressed at elevated temperature. It is found that the fabricated load cells are highly sensitive to the applied mechanical force with good repeatability. The increase in impedance of the cells is observed to be 2.0 times while the decrease in the capacitance is found to be 2.1 times as applied force increases up to 0.3 N. The average impedance and capacitive sensitivity of the cell are equal to 3.4 N^（-1） and 1.8 N^（-1）, respectively. Experimental results are compared with the simulated values,and they show that they are in reasonable agreement with each other.

关键词： carbon nanotubes flexible tensile load impedance capacitive

Effect of cold rolling on the microstructural, magnetic, mechanical, and corrosion properties of AIsI 316L austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2018年第6期25卷 630-640页

作者： s.Tanhaei kh.Gheisari s.R.Alavi Zaree Department of Materials science and Engineering Faculty of Engineering Shahid Chamran University of Ahvaz steel Research Center Faculty of Engineering Shahid Chamran University of Ahvaz

This study has evaluated the effect of different levels of cold rolling（from 0 to 50%）on the microstructural,magnetic,and mechanical properties and the corrosion behavior of 316L austenitic stainless steel in Na Cl（1 mol/L）＋H_2sO_4（0.5 mol/L）*** examinations using optical microscopy revealed the development of a morphological texture from coaxial to elongated grains during the cold-rolling *** analysis carried out on the basis of X-ray diffraction confirmed the formation of the ferromagneticα′-martensite phase under the stresses applied during cold *** finding is in agreement with magnetic measurements using a vibrating sample *** properties determined by tensile and Vickers microhardness tests demonstrated an upward trend in the hardness-to-yield strength ratio with increasing cold-rolling percentage,representing a reduction in the material’s work-hardening *** and localized corrosion parameters were estimated via potentiodynamic polarization corrosion tests and electrochemical impedance *** contrast to the uniform corrosion,wherein the corrosion current density increased with increasing cold-working degree because of the high density of microstructural defects,the passive potential range and breakdown potential increased by cold working,showing greater resistance to pit *** pits were formed,the cold-rolled material repassivation tendency decreased because of the broader hysteresis anodic loop,as confirmed experimentally by observation of the microscopic features after electrochemical cyclic polarization evaluations.

关键词： 316L stainless steel cold rolling morphological texture martensitic phase transformation work-hardening ability repassivation tendency

Impedance hygrometer based on cellulose and CuPc

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Journal of semiconductors 2010年第6期31卷 70-73页

作者： kh.s.Karimov T.A.Qasuria Zubair Ahmad Ghulam Ishaq khan Institute of Engineering sciences and Technology Physical Technical Institute Aini St.299/1Dushanbe

An investigation has been made on the properties of an impedance hygrometer fabricated using cellulose and copper phthalocyanine（Ag/cellulose/CuPc/Ag）.A 5wt%suspension of cellulose was prepared in water while the CuPc was dissolved in *** film was deposited on glass substrates with preliminary deposited metallic electrodes followed by deposition of CuPc *** resistances and capacitances of the samples were evaluated under the effect of *** impedance was calculated from resistance and capacitance *** was also measured during the *** was observed that the capacitance of the sensor increases and resistance and impedance decrease with an increase in the relative humidity *** was found that the impedance-humidity relationship showed more uniform changes in the interval of 31%—98%RH than the resistance-and capacitance-humidity relationships that showed visible changes in the humidity intervals of 31%-80%RH and 80%-98%RH *** humidity-dependent impedance of the sample makes it attractive for use in impedance *** impedance hygrometer may be used in instruments for the environmental monitoring of humidity.

关键词： cellulose copper phthalocyanine organic hygrometer humidity impedance

ON sOLVABILITY OF A BOUNDARY VALUE PROBLEM FOR A NONHOMOGENEOUs BIHARMONIC EQUATION WITH A BOUNDARY OPERATOR OF A FRACTIONAL ORDER

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Acta Mathematica scientia 2014年第6期34卷 1695-1706页

作者： A.s.BERDYsHEV A.CABADA B.kh.TURMETOV Department of Applied Mathematics and Informatics Kazakh National Pedagogical University named after AbaiAlmatyKazakhstan Departmento de Analise Matematica Facultade de Matematicas University of Santiago de CompostelaSantiago de Compostela Spain khoja Ahmet Yasawi International Kazakh-Turkish University Kazakhstan

This paper is concerned with the solvability of a boundary value problem for a nonhomogeneous biharmonic equation. The boundary data is determined by a differential operator of fractional order in the Riemann-Liouvill... 详细信息

关键词： biharmonic equation boundary value problem fractional derivative the RiemannLiouville operator