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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

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

Thermal Conductivity and Dynamic Viscosity of Highly Mineralized Water

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Fluid Dynamics & Materials Processing 2022年第3期18卷 851-866页

作者： Dadang Mohamad Mohammed Abed Jawad John William Grimaldo Guerrero Tonton Taufik Rachman Huynh Tan Hoi Albert kh.Shaikhlislamov Mustafa M.Kadhim Saif Yaseen Hasan A.Surendar Building Engineering Educatation Universitas Pendidikan IndonesiaBandung45363Indonesia Al-Nisour University College Iraq10004Baghdad Departamento de Energía Universidad de la CostaBarranquilla080002Colombia Universitas Masoem Bandung45363Indonesia Department of Language FPT UniversityHanoi700000Vietnam Kazan Federal University RussiaKazan420000Russia Dentistry Department Kut University CollegeKutWasitIraqCollege of Technical EngineeringThe Islamic UniversityNajaf54001Iraq National University of Science and Technology Dhi-Qar64001Iraq Department of Pharmacology Saveetha Dental College and HospitalSaveetha Institute of Medical and Technical SciencesChennai600056India

Further development in the field of geothermal energy require reliable reference data on the thermophysical properties of geothermal waters,namely,on the thermal conductivity and viscosity of aqueous salt solutions at temperatures of 293–473 K,pressures Ps=100 MPa,and concentrations of 0–25 wt.%.Given the lack of data and models,especially for the dynamic viscosity of aqueous salt solutions at a pressure of above 40 MPa,generalized formulas are presented here,by which these gaps can be *** article presents a generalized formula for obtaining reliable data on the thermal conductivity of water aqueous solutions of salts for Ps=100 MPa,temperatures of 293–473 K and concentrations of 0%–25%(wt.%),as well as generalized formulas for the dynamic viscosity of water up to pressures of 500 MPa and aqueous solutions of salts for Ps=100 MPa,temperatures 333–473 K,and concentration 0%–25%.The obtained values agree with the experimental data within 1.6%.

关键词： Thermal conductivity dynamic viscosity water-salt systems aqueous solutions of salts high pressure multicomponent water-salt system

Voltage regulation in LV grids by coordinated volt-var control strategies

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Journal of Modern Power Systems and Clean Energy 2014年第4期2卷 319-328页

作者： Miguel JUAMPEREZ Guangya YANG Søren Bækhøj KJÆR Center for Electric Power and Energy Department of Electrical EngineeringTechnical University of DenmarkElektrovej Building 3252800 Kgs.LyngbyDenmark Danfoss Solar Inverters A/S Ulsnæs 16300 Gra°stenDenmark

The increasing penetration level of photovoltaic(PV)power generation in low voltage(LV)networks results in voltage rise issues,particularly at the end of the *** order to mitigate this problem,several strategies,such as grid reinforcement,transformer tap change,demand-side management,active power curtailment,and reactive power optimization methods,show their contribution to voltage support,yet still *** paper proposes a coordinated volt-var control architecture between the LV distribution transformer and solar inverters to optimize the PV power penetration level in a representative LV network in Bornholm Island using a multi-objective genetic *** approach is to increase the reactive power contribution of the inverters closest to the transformer during overvoltage *** standard reactive power control concepts,cosu(P)and Q(U),are simulated and compared in terms of network power losses and voltage level along the *** a practical implementation,a reconfigurable hardware is used for developing a testing platform based on real-time measurements to regulate the reactive power *** proposed testing platform has been developed within *** project,which targets to study the approaches for large PV power integration into the network,without the need of reinforcement.

关键词： Voltage regulation Reactive power optimization Genetic algorithm

COMPARISON　OF　CATALYTIC　REACTIVITIES　OF　TRIPHENYL－PHOSPHINE　COMPLEXES　OF　Ru，Rh，Pd，Fe，Co，Ni　IN　THE　MALEIC　ANHYDRIDE　HYDROGENATION

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Chinese Chemical Letters 1995年第4期6卷 343-344页

作者： Li, JP Li, ZS Tian, X Yang, kh Liaoning Normal Univ Dept Chem Dalian 116022 Peoples R China

The Sequence of homogeneous catalytic reactivity of triphenylphosphine complexes of Ru, Rh, Pd, Fe, Co, Ni in the maleic anhydride hydrogenation is:Rucl2 (PPh3)3> RhCI (PPh3)3> NiCI2 (PPh3)2>CoCl2 (PPh3) 2> FeCI2 (PPh... 详细信息

关键词： Pd COMPLEXES MALEIC THE PHOSPHINE TRIPHENYL COMPARISON OF Ru ANHYDRIDE Rh Fe Ni

A Study on the Wear Behaviour of Dual Phase Steels

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Journal of Materials Science & Technology 2007年第1期23卷 107-110页

作者： V.Abouei H.Saghafian Sh.kheirandish kh.Ranjbar Department of Metallurgy and Materials Engineering Iran University of Science and TechnologyIran Shahid Chamran University Iran

Dual phase （DP） steels containing four different amounts of martensite ranging from 43 vol. pct to 81 vol. pct have been developed from 0.2 wt pct carbon steel by intercritical heat treatment at a fixed temperature of 780℃ with varying holding times followed by water quenching. Dry sliding wear tests have been conducted on DP steels using a pin- on-disk machine under different normal loads of 61.3, 68.5, 75.7 and 82.6 N and at a constant sliding speed of 1.20 m/s. At these loads, the mechanism of wear is primarily delamination, which has been confirmed by SEM micrographs of subsurface and wear debris of samples. Wear properties have been found to improve with the increase in martensite volume fraction in dual phase steels.

关键词： Wear Dual phase steel Microstructure

Quark-hadron phase transition in DGP including BD brane

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Chinese Physics C 2020年第8期44卷 98-107页

作者： Tayeb Golanbari Terife Haddad Abolhassan Mohammadi M.A.Rasheed kh.Saaidi Department of Physics Faculty of ScienceUniversity of KurdistanPasdaran St.P.O.Box 66177-15175SanandajIran Department of Physics Faculty of ScienceRazi UniversityKermanshah ***Iran Development Center for Research and Training(DCRT) University of Human DevelopmentSulaimaniKurdistan RegionIraq Department of Physics College of ScienceUniversity of SulaimaniKurdistan RegionIraq

A Dvali–Gabadadze–Porrati(DGP)brane-world model with perfect fluid brane matter including a Brans-Dicke(BD)scalar field on brane was utilized to investigate the problem of the quark-hadron phase(QHP)transition in early evolution of the *** presence of the BD scalar field arises with several modified terms in the Friedmann *** the behavior of the phase transition strongly depends on the basic evolution equations,even a small change in these relations might lead to interesting results about the time of *** phase transition is investigated in two scenarios,namely the first-order phase transition and smooth crossover phase *** the first-order scenario,which is used for the intermediate temperature regime,the evolution of the physical quantities,such as temperature and scale factor,are investigated before,during,and after the phase *** results show that the transition occurs in about a *** the following part,the phenomenon is studied by assuming a smooth crossover transition,where the lattice QCD data is utilized to obtain a realistic equation for the state of the *** investigation for this part is performed in the high and low-temperature *** the trace anomaly in the high-temperature regime specifies a simple equation of state,which states that the quark-gluon behaves like ***,in the low-temperature regime,the trace anomaly is affected by discretization effects,and the hadron resonance gas model is utilized *** this model,a more realistic equation of state is found in the low-temperature *** crossover phase transition in both regimes is *** results determine that the transition lasts around a few ***,the transition in the low-temperature regime occurs after the transition in the high-temperature regime.

关键词： DGP brane-world quark-hadron phase lattic QCD

Mode-I crack in a two-dimensional fibre-reinforced generalized thermoelastic problem

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Chinese Physics B 2012年第1期21卷 244-253页

作者： kh.Lotfy Department of Mathematics Faculty of ScienceZagazig UniversityZagazig P.O.Box 44519Egypt Department of Mathematics Faculty of Science and ArtsAl-mithnabQassim UniversityP.O.Box 931Buridah 51931Al-mithnabKingdom of Saudi Arabia

A general model of the equations of the Lord-Sulman theory including one relaxation time and the Green-Lindsay theory with two relaxation times, as well as the classical dynamical coupled theory, are applied to the study of the influence of reinforcement on the total deformation for an infinite space weakened by a finite linear opening mode- I crack. We study the influence of reinforcement on the total deformation of rotating thermoelastic half-space and their interaction with each other. The material is homogeneous isotropic elastic half space. The crack is subjected to prescribed temperature and stress distributions. The normal mode analysis is used to obtain the exact expressions for displacement components, force stresses, and temperature. The variations of the considered variables with the horizontal distance are illustrated graphically. Comparisons are made with the results obtained in the three theories with and without rotation. A comparison is also made between the two theories for different depths.

关键词： mode-I crack Lord -Sulman theory thermoelasticity normal mode analysis.