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Transient peristaltic diffusion of nanofluids: A model of micropumps in medical engineering

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Journal of Hydrodynamics 2018年第6期30卷 1001-1011页

作者： Dharmendra Tripathi Shashi bhushan o.anwar bég Noreen Sher Akbar Department of Science and Humanities National Institute of TechnologyUttarakhand–246174 India Department of Mechanical Engineering Manipal University Department of Aeronautical and Mechanical Engineering University of Salford DbS & H CEME National University of Sciences and TechnologyIslamabad Pakistan

Peristaltic micro-pumps offer an excellent mechanism for delivery of a variety of medicines including drugs, corneal solutions etc. The surge in deployment of nanoparticles in medicine has provided new potential for such pumps. In light of this we investigate the time-dependent peristaltic flow of nanofluids with diffusive effects through a finite non-uniform channel, this geometry being more representative of real micro-pumps. Creeping flow is taken into account(inertial forces are small compared with viscous forces) i.e., Reynolds number is low(Regth is also taken to be very large. The buongiorno formulation for nanofluids is employed with an oberbeck-boussinesq approximation. Closed-form solutions are developed for the non-dimensional governing equations subject to physically realistic boundary conditions. Mathematica symbolic software is employed to evaluate the evolution of nanoparticle fraction, temperature, axial velocity, transverse velocity and pressure difference distribution along the length of the pump channel with variation in thermal grashof number, basic-density(species i.e., mass) grashof number, brownian motion parameter and thermophoresis parameter.

关键词： Unsteady flow peristaltic pumps nanofluids medical engineering diffusive process grashof number thermophoresis

Effects of thermophoresis particle deposition and of the thermal conductivity in a porous plate with dissipative heat and mass transfer

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Acta Mechanica Sinica 2011年第3期27卷 389-398页

作者： Joaquín Zueco o.anwar bég L.M.Lpez-ochoa Thermal Engineering and Fluids Department Technical University of CartagenaETSII Campus Muralla del Mar Aerospace Engineering Department of Engineering and MathematicsSheaf BuildingSheffield Hallam University Mechanical Engineering Departament University of RiojaC/Luís de UlloaLogrono (La Rioja)20E-26004Spain

Network simulation method（NSM） is used to solve the laminar heat and mass transfer of an electricallyconducting,heat generating/absorbing fluid past a perforated horizontal surface in the presence of viscous and Joule heating problem. The governing partial differential equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations,in a single independent variable,畏. The resulting coupled,nonlinear equations are solved under appropriate transformed boundary conditions. Computations are performed for a wide range of the governing flow parameters,viz Prandtl number,thermophoretic coeffcient（a function of Knudsen number）,thermal conductivity parameter,wall transpiration parameter and Schmidt number. The numerical details are discussed with relevant applications. The present problem finds applications in optical fiber fabrication,aerosol filter precipitators,particle deposition on hydronautical blades,semiconductor wafer design,thermo-electronics and problems including nuclear reactor safety.

关键词： Thermophoresis . MHD . Network simulation model . Heat and mass transfer- Hartmann number

Analytical approach to entropy generation and heat transfer in CNT-nanofluid dynamics through a ciliated porous medium

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Journal of Hydrodynamics 2018年第2期30卷 296-306页

作者： Noreen Sher Akbar M.Shoaib Dharmendra Tripathi Shashi bhushan o.anwar bég DbS&H CEME National University of Sciences and Technology School of Natural Sciences National University of Sciences and Technology Department of Mechanical Engineering Manipal University Medical Energy and Propulsion Engineering Sciences Department of Aeronautical and Mechanical Engineering University of Salford

The transportation of biological and industrial nanofluids by natural propulsion like cilia movement and self-generated contraction-relaxation of flexible walls has significant applications in numerous emerging technologies. Inspired by multi-disciplinary progress and innovation in this direction, a thermo-fluid mechanical model is proposed to study the entropy generation and convective heat transfer of nanofluids fabricated by the dispersion of single-wall carbon nanotubes（SWCNT） nanoparticles in water as the base fluid. The regime studied comprises heat transfer and steady, viscous, incompressible flow, induced by metachronal wave propulsion due to beating cilia, through a cylindrical tube containing a sparse（i.e., high permeability） homogenous porous medium. The flow is of the creeping type and is restricted under the low Reynolds number and long wavelength approximations. Slip effects at the wall are incorporated and the generalized Darcy drag-force model is utilized to mimic porous media effects. Cilia boundary conditions for velocity components are employed to determine analytical solutions to the resulting non-dimensionalized boundary value problem. The influence of pertinent physical parameters on temperature, axial velocity, pressure rise and pressure gradient, entropy generation function, bejan number and stream-line distributions are computed numerically. A comparative study between SWCNT-nanofluids and pure water is also computed. The computations demonstrate that axial flow is accelerated with increasing slip parameter and Darcy number and is greater for SWCNT-nanofluids than for pure water. Furthermore the size of the bolus for SWCNT-nanofluids is larger than that of the pure water. The study is applicable in designing and fabricating nanoscale and microfluidics devices, artificial cilia and biomimetic micro-pumps.

关键词： Metachronal wave single-wall carbon nanotubes (SWCNT) entropy generation porous medium cilia motion heat transfer bejan number

Cilia-assisted hydromagnetic pumping of biorheological couple stress fluids

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Propulsion and Power Research 2019年第3期8卷 221-233页

作者： K.Ramesh D.Tripathi o.anwar bég Department of Mathematics Symbiosis Institute of TechnologySymbiosis International UniversityPune412115India Department of Mechanical Engineering Manipal University JaipurRajasthan303007India Fluid Mechanics/Propulsion Aeronautical/Mechanical Engineering DepartmentSalford UniversityManchesterUK

A theoretical study is conducted for magnetohydrodynamic pumping of electroconductive couple stress physiological liquids(***)through a two-dimensional ciliated channel.A geometric model is employed for the cilia which are distributed at equal intervals and produce a whip-like motion under fluid interaction which obeys an elliptic trajectory.A metachronal wave is mobilized by the synchronous beating of cilia and the direction of wave propagation is parallel to the direction of fluid flow.A transverse static magnetic field is imposed transverse to the channel *** Stokes’couple stress(polar)rheological model is utilized to characterize the *** normalized two-dimensional conservation equations for mass,longitudinal and transverse momentum are reduced with lubrication approximations(long wavelength and low Reynolds number assumptions)and feature a fourth order linear derivative in axial velocity representing couple stress contribution.A coordinate transformation is employed to map the unsteady problem from the wave laboratory frame to a steady problem in the wave *** slip conditions are imposed at the channel *** emerging linearized boundary value problem is solved analytically and expressions presented for axial(longitudinal)velocity,volumetric flow rate,shear stress function and pressure *** flow is effectively controlled by three geometric parameters,viz cilia eccentricity parameter,wave number and cilia length and two physical parameters,namely magnetohydrodynamic(MHD)body force parameter and couple stress non-Newtonian *** solutions are numerically evaluated with MATLAb *** velocity is observed to be enhanced in the core region with greater wave number whereas it is suppressed markedly with increasing cilia length,couple stress and magnetic parameters,with significant flattening of profiles with the latter two *** pressure gradient is decreased with eccentricity parameter whereas it is ele

关键词： Magneto hydrodynamics Metachronal waves Cilia Synchronous beating Polar couple stress fluid Physiological transport Magnetic blood pumps

Numerical solution of thermo-solutal mixed convective slip flow from a radiative plate with convective boundary condition

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Journal of Hydrodynamics 2016年第3期28卷 451-461页

作者： m.j.uddin o.anwar bég m.n.uddin a.i.md.ismail Department of Mathematics American International University-BangladeshDhakaBangladesh Fluid Mechanics Spray Research GroupPetroleum and Gas Engineering DivisionRoom G77Newton BuildingSchool of ComputingScience and Engineering(CSE)University of SalfordM54WTUK Department of Mathematical Sciences Ball State University2000 W University AvenueMuncieIN 47306USA School of Mathematical Sciences Universiti Sains MalaysiaPenang 11800Malaysia

A mathematical model for mixed convective slip flow with heat and mass transfer in the presence of thermal radiation is presented. A convective boundary condition is included and slip is simulated via the hydrodynamic slip parameter. Heat generation and absorption effects are also incorporated. The Rosseland diffusion flux model is employed. The governing partial differential conservation equations are reduced to a system of coupled, ordinary differential equations via Lie group theory method. The resulting coupled equations are solved using shooting method. The influences of the emerging parameters on dimensionless velocity, tempera- ture and concentration distributions are investigated. Increasing radiative-conductive parameter accelerates the boundary layer flow and increases temperature whereas it depresses concentration. An elevation in convection-conduction parameter also accelerates the flow and temperatures whereas it reduces concentrations. Velocity near the wall is considerably boosted with increasing momentum slip parameter although both temperature and concentration boundary layer thicknesses are decreased. The presence of a heat source is found to increase momentum and thermal boundary layer thicknesses but reduces concentration boundary layer thickness. Excelle- nt correlation of the numerical solutions with previous non-slip studies is demonstrated. The current study has applications in bio- reactor diffusion flows and high-temperature chemical materials processing systems.

关键词： slip flow thermal radiation lie group theory heat source/sink materials processing

biomathematical model for gyrotactic free-forced bioconvection with oxygen diffusion in near-wall transport within a porous medium fuel cell

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International Journal of biomathematics 2020年第4期13卷 141-165页

作者： Nayema Islam Nima M.Ferdows o.anwar beg S.Kuharatt Faris Alzahranit Research group of Fluid Flow Modeling and Simulation Department of Applied Mathematics University of Dhaka Dhaka-100Bangladesh Multi-Physical Engineering Sciences group Aeronautical/Mechanical Engineering School of Science Engineering and Environment(SEE)University of SalfordManchesterUK

bioconvection has shown significant promise for environmentally friendly,sustainable“green”fuel cell *** improved design of such systems requires continuous refinements in biomatheatical modeling in conjunction with laboratory and *** by exploring deeper the near-wall transport phenomena involved inbio-inspired fuel cells,in the present paper,we examine analytically and numericallythe combined free-forced convective steady boundary layer flow from a solid verticalflat plate embedded in a Darcian porous medium containing gyrotactic *** is one of the many taxes exhibited in biological microscale transport,andother examples include magneto-taxis,photo-taxis,chemotaxis and geo-taxis (reflecting the response of microorganisms to magnetic field,light,chemical concentration orgravity,respectively). The bioconvection fuel cell also contains difusing oxygen specicswhich mimics the cathodic behavior in a proton exchange membrane(PEM) *** wall is maintained at isosolutal (constant oxygen volume fraction and motilemicroorganism density) and iso-thermal conditions. Wall values of these quantities aresustained at higher values than the ambient temperature and concentration of oxygenand biological microorganism *** transformations are applied to renderthe governing partial differential equations for mass,momentum,energy,oxygen speciesand microorganism species density into a system of ordinary differential equations. Theemerging eight order nonlinear coupled,ordinary differential boundary value problemfeatures several important dimensionless control parameters,namely Lewis number(Le),buoyancy ratio paraneter i.e. ratio of oxygen species buoyancy force to thermal buoy-ancy force(Nr), bioconvection Rayleigh number(Rb), bioconvection Lewis number(Lb),bioconvection Peclet number(Pe) and the mixed convection parameter(e) spanning theentire range of free and forced convection. The transformed nonlinear sys

关键词： bioconvection gyrotactic microorganisms oxygen diffusion buoyancy Lewis number boundary layers fuel cells numerical solution Nusselt nurnber Sherwood number

Phase Noise Quenching in a Four-Level Laser

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Chinese Physics Letters 2010年第3期27卷 184-187页

作者： Javaid anwar Department of Physics COMSATS Institute of Information Technology Islamabad Pakistan

In the presence of usual transmission losses, it is shown that phase noise in a four-level laser can be reduced below the Schawlow-Townes limit when lasing levels are coupled to a squeezed vacuum reservoir. The squeezed vacuum coupled to the lasing mode modifies the phase diffusion rate and dominates the contribution from transmission losses. It is predicted to obtain phase stability in the system and phase noise vanishes for larger squeezing. gain of the laser remains positive under these conditions.

关键词： optics quantum optics and lasers

Production of hydrogen from fossil fuel:A review

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Frontiers in Energy 2023年第5期17卷 585-610页

作者： Shams anwar Xianguo LI Laboratory for Fuel Cell and green Energy Department of Mechanical and Mechatronics EngineeringUniversity of WaterlooWaterlooOntario N2L3G1Canada

Production of hydrogen,one of the most promising alternative clean fuels,through catalytic conversion from fossil fuel is the most technically and economically feasible *** conversion of natural gas into hydrogen and carbon is thermodynami-cally favorable under atmospheric ***,using noble metals as a catalyst is costly for hydrogen production,thus mandating non-noble metal-based catalysts such as Ni,Co,and Cu-based *** paper reviews the various hydrogen production methods from fossil fuels through pyrolysis,partial oxidation,autother-mal,and steam reforming,emphasizing the catalytic production of hydrogen via steam reforming of *** multicomponent catalysts composed of several non-noble materials have been *** the Ni,Co,and Cu-based catalysts investigated in the literature,Ni/Al_(2)o_(3)catalyst is the most economical and performs best because it suppresses the coke formation on the *** avoid carbon emission,this method of hydrogen production from methane should be integrated with carbon capture,utilization,and storage(CCUS).Carbon capture can be accomplished by absorption,adsorption,and membrane separation *** remaining challenges,prospects,and future research and development directions are described.

关键词： methane catalytic conversion natural gas hydrogen production CCUS

Polycyclic aromatic hydrocarbon in rain and street runoff in Amman, Jordan

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Journal of Environmental Sciences 2003年第6期15卷 848-853页

作者： anwar. g. Jiries Helmi. H. Hussein Jutta Lintelmann Mutah University Water and Environment Research CenterDepartment of Chemistry Ottawa UniversityGSF National Research Center for Environment and Health-D 85764 Karak Jordan. 10 Marie Curie Ottawa Ontario K1N 6N5 CanadaNeuherbergGermany

Concentrations of polycyclic aromatic hydrocarbons(PAHs) were determined in the rain and street runoff samples from two sites in the vicinity of Amman City during the pluvial period 1999—2000. The results showed that elevated levels of PAHs were detected in the city center(site 1) than the residential area(site 2) and that the levels were higher in street runoff than rain samples of the same sites. The highest concentration of PAHs in both street runoff and rain samples were observed in the first rainy month(November 1999) which indicated a wash out effect of PAHs originating from vehicular emission accumulated during the long dry summer season before sampling. Within the investigated cold winter seasons, fluctuations in PAHs concentration were observed. The variation was attributed to the fossil combustion for heating purposes and to intervals between rainfalls: as the longer the intervals between rains were, the higher the PAH concentration were. Removal of PAHs from the atmosphere through precipitation over the investigated period varied with time and places depending on the amount of rainfall where higher rainfall removed higher amount of PAHs from the atmosphere. The amount of PAHs washed out through precipitation was estimated to be around 14.8 mg/m 2 and 21.1 mg/m 2 for sites 1 and 2 respectively.

关键词： PAHs rain street runoff Jordan