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Hybrid nanomaterial flow and heat transport in a stretchable convergent/divergent channel:a Darcy-Forchheimer model

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Applied Mathematics and Mechanics(English Edition) 2020年第5期41卷 699-710页

作者： g.k.ramesh S.A.SHEHZAD I.TLILI Department of Mathematics K.L.E Society’s J.T.CollegeGadag 582101KarnatakaIndia Department of Mathematics COMSATS University IslamabadSahiwal 57000Pakistan Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh City 758307Vietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh City 758307Vietnam

The flow behavior in non-parallel walls is an important factor of any physical model including cavity flow and canals, which is applicable for diverging/converging channel. The present communication explains that the flow of the hybrid nanomaterial subjected to the convergent/divergent channel has non-parallel walls. It is assumed that the hybrid nanomaterial movement is in the porous region. A Darcy-Forchheimer medium of porosity is considered to interpret the porosity features. A useful similarity function is adopted to get the strong ordinary coupled equations. Numerical solutions are achieved through the Runge-kutta-Fehlberg(RkF) fourth-fifth order method, and they are validated with the existing results. Physical nature of the involving constraints is reported with the help of plots. It is explored that the velocity of divergent channel decreases, and convergent channel enhances for the higher solid volume faction. Further, the presence of inertia coefficient and porosity parameter amplifies the velocity at the wall.

关键词： hybrid nanoliquid channel Darcy-Forchheimer flow stretching wall numerical solution

Bioconvective nanofluid flow over an exponential stretched sheet with thermophoretic particle deposition

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Propulsion and Power Research 2023年第2期12卷 284-296页

作者： B.C.Prasannakumara J.k.Madhukesh g.k.ramesh Department of Studies in Mathematics Davangere UniversityDavangereKarnataka 577002India Department of Mathematics K.L.E.Society’s J.T.CollegeGadagKarnataka 582101India Department of Mathematics Amrita School of EngineeringAmrita Vishwa VidyapeethamBengaluruIndia

The current work is being done to investigate the flow of nanofluids across a porous exponential stretching surface in the presence of a heat source/sink,thermophoretic particle deposition,and *** collection of PDEs(partial differential equations)that represent the fluid moment is converted to a system of ODEs(ordinary differential equations)with the use of suitable similarity variables,and these equations are then numerically solved using Runge kutta Fehlberg and the shooting *** different physical limitations,the numerical results are visually *** results show that increasing the porosity characteristics reduces *** mass transfer decreases as the thermophoretic limitation *** in the porosity parameter reduce skin friction,increases in the solid volume fraction improve the rate of thermal distribution,and increases in the thermophoretic parameter increase the rate of mass transfer.

关键词： Exponential stretching sheet Nanofluid Heat source/sink Thermophoretic particle deposition Bio convection

Bio-Marangoni convection flow of Casson nanoliquid through a porous medium in the presence of chemically reactive activation energy

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Applied Mathematics and Mechanics(English Edition) 2021年第8期42卷 1191-1204页

作者： J.k.MADHUkESH g.k.ramesh B.C.PRASANNAkUMARA S.A.SHEHZAD F.M.ABBASI Department of Mathematics Davangere UniversityDavangere 577007India Department of Mathematics K.L.E.Society’s J.T.CollegeGadag 582101India Department of Mathematics COMSATS University IslamabadSahiwal 57000Pakistan

Bioconvection research is primarily focused on the augmentation of energy and mass species,which has implications in the processes intensification,mechanical,civil,electronics,and chemical engineering *** bioconvection technology sectors include cooling systems for electronic devices,building insulation,and geothermal nuclear waste ***,the present investigation is mainly discoursing the impact of Marangoni convention Casson nanoliquid flow under gyrotactic microorganisms over the porous *** partial differential equations(PDEs)are re-structured into ordinary differential equations(ODEs)via suitable similar *** ODEs are numerically solved with the help of the spectral relaxation method(SRM).The numerical outcomes are illustrated graphically for various parameters over velocity,temperature,concentration,and bioconvection ***-dimensional(3 D)views of important engineering parameters are illustrated for various *** velocity of the Casson nanoliquid increases with increasing the Marangoni parameter but decreases against higher porosity *** surface drag force enhances for enhancement in the Marangoni *** rate of mass transmission is higher for reaction rate constraint but diminishes for activation energy *** higher radiative values augment the rate of heat transmission.

关键词： Casson nanofluid activation energy thermal radiation bioconvection Marangoni convection

Analysis of Heat Transfer Phenomenon in Magnetohydrodynamic Casson Fluid Flow Through Cattaneo–Christov Heat Diffusion Theory

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Communications in Theoretical Physics 2017年第7期67卷 91-95页

作者： g. k. ramesh J. gireesha, S. A. Shehzad, F. M. Abbasi Department of Mathematics School of Engineering Presidency University Bengaluru-560089 Karnataka India Department of Studies and Research in Mathematics Kuvempu University Shankaraghatta-577451 Shimoga Karnataka India Department of Mathematics COMSATS Institute of Information Technology Sahiwal-57000 Pakistan Department of Mathematics COMSATS Institute of Information Technology Islamabad-44000 Pakistan

Heat transport phenomenon of two-dimensional magnetohydrodynamie Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated in the mathematical modeling of present flow problem. The governing mathematical expressions are solved for velocity and temperature profiles using RkF 45 method along with shooting technique. The importance of arising nonlinear quantities namely velocity, temperature, skin-friction and temperature gradient are elaborated via plots. It is explored that the Casson parameter retarded the liquid velocity while it enhances the fluid temperature. Fhrther, we noted that temperature and thickness of temperature boundary layer are weaker in case of Cattaneo-Christov heat diffusion model when matched with the profiles obtained for Fourier＇s theory of heat flux.

关键词： Hydromagnetic flow Casson fluid heat transfer Cattaneo-Christov heat diffusion model numer-ical solution

Electro-magneto-hydrodynamic flow of couple stress nanofluids in micro-peristaltic channel with slip and convective conditions

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 593-606页

作者： k.ramesh M.g.REDDY B.SOUAYEH Department of Mathematics Symbiosis Institute of TechnologySymbiosis International(Deemed University)Pune 412115India Department of Mathematics Acharya Nagarjuna UniversityOngole CampusOngole 523001India Department of Physics College of ScienceKing Faisal UniversityAl-Ahsa 31982Saudi Arabia Laboratory of Fluid Mechanics Physics DepartmentFaculty of Sciences of TunisUniversity of Tunis El ManarTunis 2092Tunisia

This study explores the effects of electro-magneto-hydrodynamics,Hall currents,and convective and slip boundary conditions on the peristaltic propulsion of nanofluids(considered as couple stress nanofluids)through porous symmetric *** phenomena of energy and mass transfer are considered under thermal radiation and heat source/*** governing equations are modeled and non-dimensionalized under appropriate dimensionless *** resulting system is solved numerically with MATHEMATICA(with an in-built function,namely the Runge-kutta scheme).graphical results are presented for various fluid flow quantities,such as the velocity,the nanoparticle temperature,the nanoparticle concentration,the skin friction,the nanoparticle heat transfer coefficient,the nanoparticle concentration coefficient,and the trapping *** results indicate that the nanoparticle heat transfer coefficient is enhanced for the larger values of thermophoresis ***,an intriguing phenomenon is observed in trapping:the trapped bolus is expanded with an increase in the Hartmann ***,the bolus size decreases with the increasing values of both the Darcy number and the electroosmotic parameter.

关键词： peristalsis magnetohydrodynamics(MHD) nanofluid Hall current porous medium thermal radiation

Advancement in utilization of magnetic resonance imaging and biomarkers in the understanding of schizophrenia

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World Journal of Clinical Cases 2025年第1期13卷 11-15页

作者： Aidan k Tirpack Danyaal g Buttar Mandeep kaur Department of Psychiatry Campbell University School of Osteopathic MedicineBuies CreekNC 27506United States Department of Psychiatry and Behavioral Health Mercyhealth Hospital and Trauma CenterJanesvilleWI 53548United States

Historically,psychiatric diagnoses have been made based on patient’s reported symptoms applying the criteria from diagnostic and statistical manual of mental *** utilization of neuroimaging or biomarkers to make the diagnosis and manage psychiatric disorders remains a distant *** have been several studies that examine brain imaging in psychiatric disorders,but more work is needed to elucidate the complexities of the human *** this editorial,we examine two articles by Xu et al and Stoyanov et al,that show developments in the direction of using neuroimaging to examine the brains of people with schizo-phrenia and *** et al used magnetic resonance imaging to examine the brain structure of patients with schizophrenia,in addition to examining neurotransmitter levels as *** et al used functional magnetic resonance imaging to look at modulation of different neural circuits by diagnostic-specific scales in patients with schizophrenia and *** two studies provide crucial evidence in advancing our understanding of the brain in prevalent psychiatric disorders.

关键词： Schizophrenia Magnetic resonance imaging Biomarkers Neurotransmitters Psychiatric disorders

Experimental Investigation for NO_x Emission Reduction in Hydrogen Fueled Spark Ignition Engine Using Spark Timing Retardation, Exhaust gas Recirculation and Water Injection Techniques

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Journal of Thermal Science 2019年第4期28卷 789-800页

作者： JEERAgAL ramesh k.A.Subramanian Engines and Unconventional Fuels Laboratory Centre for Energy Studies IIT Delhi

The experimental tests were carried out on a single cylinder hydrogen fueled spark ignition(SI)generator set with different spark timings(4-20℃A bTDC),exhaust gas recirculation(EgR)up to 28% by volume and water injection up to 1.95 kg/h(maximum water to fuel mass ratio of 8:1).The engine speed was kept constant of 3000 r/*** NOx emission and thermal efficiency of engine with gasoline and hydrogen fuel operation at 1.4 kW power output are 5 g/kWh and 12.1 g/kWh,and 15% and 20.9% *** order to reduce the NOx emission at source level,retarding spark timing,exhaust gas recirculation(EgR),and water injection techniques were *** emission decreased with spark timing retardation,EgR,and water *** emission with hydrogen at 1.4 kW power output decreased from 12.1 g/kWh with maximum brake torque(MBT)spark timing(10℃A bTDC)to 8.1 g/kWh with retarded spark timing(4℃A bTDC)due to decrease in the in-cylinder peak pressure and *** Nox emission decreased to 6.1 g/kWh with 20% EgR due to thermal and chemical dilution ***,thermal efficiency decreased about 33% and 17% with spark timing retardation and 20EgR respectively as compared to that of MBT spark ***,in the case of water injection,the NOx emission decreased significantly without affecting the thermal efficiency of the engine and it is 5.6 g/kWh with water-hydrogen ratio of 4:1(water flow rate of 0.92 kg/h).Water injection is the best suitable method to reduce the NOx emission in a hydrogen fueled engine compared with the spark timing retardation and EgR technique.

关键词： hydrogen spark ignition engine spark timing exhaust gas recirculation NOx emission water injection

Entropy generation analysis of natural convective radiative second grade nanofluid flow between parallel plates in a porous medium

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Applied Mathematics and Mechanics(English Edition) 2019年第4期40卷 481-498页

作者： k.ramesh O.OJJELA Department of Applied Mathematics Defence Institute of Advanced Technology

The present article explores the entropy generation of radiating viscoelastic second grade nanofluid in a porous channel confined between two parallel plates. The boundaries of the plates are maintained at distinct temperatures and concentrations while the fluid is being sucked and injected periodically through upper and lower plates. The buoyancy forces, thermophoresis and Brownian motion are also considered due to the temperature and concentration differences across the channel. The system of governing partial differential equations has been transferred into a system of ordinary differential equations(ODEs) by appropriate similarity relations, and a shooting method with the fourth-order Runge-kutta scheme is used for the solutions. The results are analyzed in detail for dimensionless velocity components. The temperature, concentration distributions, the entropy generation number, and the Bejan number corresponding to various fluid and geometric parameters are shown graphically. The skin friction, heat and mass transfer rates are presented in the form of tables. It is noticed that the temperature profile of the fluid is enhanced with the Brownian motion, whereas the concentration profile of the fluid is decreased with the thermophoresis parameter, and the entropy and Bejan numbers exhibit the opposite trend for the suction and injection ratio.

关键词： nanofluid thermophoresis Brownian motion shooting method thermal radiation

Effects of viscous dissipation and Joule heating on the Couette and Poiseuille flows of a Jeffrey fluid with slip boundary conditions

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Propulsion and Power Research 2018年第4期7卷 329-341页

作者： k.ramesh Department of Mathematics Symbiosis Institute of TechnologySymbiosis International UniversityPune 412115India

In this article,we have presented the exact solutions of the Couette,Poiseuille and generalized Couette flows of an incompressible magnetohydrodynamic Jeffrey fluid between parallel plates through homogeneous porous *** effects of slip boundary conditions and heat transfer are *** dissipation,radiation and Joule heating are also considered in the energy *** governing equations of the Jeffrey fluid flow are modeled in Cartesian coordinate *** solutions for the velocity and temperature the velocity and temperature profiles are studied and the results are presented through *** Temperature behaves as a decreasing function due to the impact of Hartmann number,non-Newtonian parameter and slip parameter in all noted problems.

关键词： Jeffrey fluid Heat transfer Joule heating Radiation Viscous dissipation Slip boundary conditions