Top PDF Investigation of Mixed Convection in a Vertical Microchannel Affected by EDL

Heat Transfer in MHD Mixed Convection Flow of a Ferrofluid along a Vertical Channel.

Heat Transfer in MHD Mixed Convection Flow of a Ferrofluid along a Vertical Channel.

Nanofluids have numerous applications in nano-scale flow. In this type of flow the molecu- lar structure of the fluid and surfaces, andinteraction between them at the atomistic length scale play a key role and hence the molecular dynamics (MD) method emerges as a viable approach for investigation of the flow in such scale. Examples of nano-scale flows include bubbfil spinning, bubble electrospinning, blown bubble spinning, membrane spinning pro- cesses used for nanofiber fabrication. Bubbfil spinning is a nanoscale flow process in which polymer/melts, bubbles/membranes are used for fabrication of nanofibers by using electrostatic force, flowing air or mechanical force (e.g. centrifugal force) to overcome the surface tension of bubble[5]. Chen et al. [6]studied bubbfil spinning process for mass-production of nanofibers. He et al. [7] analyzed various characteristics of Nanoscale flow with some interesting results.
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Mixed convection stagnation-point flow of  nanofluids over a stretching/shrinking sheet in a porous medium with internal heat generation/absorption

Mixed convection stagnation-point flow of nanofluids over a stretching/shrinking sheet in a porous medium with internal heat generation/absorption

Uddin et al. [13] studied free convective boundary layer flow of a nanofluid over a permeable upward horizontal plate in a porous medium with thermal convective boundary condition. Rana and Bhargava [14] studied the heat transfer enhancement in mixed convection flow along a vertical plate with heat source/sink utilizing nanofluids. Chamkha and Aly [15] focused on steady convection boundary layer flow of a nanofluid along a permeable vertical plate in the presence of magnetic field, heat generation/absorption and suction/injection effects. Recently, Rahman et al. [16] investigated hydromagnetic slip flow of water based nanofluid over a wedge with convective surface in the presence of heat generation or absorption. A similarity solution of the steady boundary layer near the stagnation-point flow on a permeable stretching sheet in a porous medium saturated with a nanofluid in the presence of heat generation/absorption is studied by Hamad and Pop [17]. An important numerical investigation on the convective heat transfer performance of nanofluids over a permeable stretching surface in the presence of partial slip, thermal buoyancy and internal heat generation or absorption was presented by Das [18].
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Numerical Study on MHD Mixed Convection Flow in a Vertical Insulated Square Duct with Strong Transverse Magnetic Field

Numerical Study on MHD Mixed Convection Flow in a Vertical Insulated Square Duct with Strong Transverse Magnetic Field

negligible in comparison with the velocity of the forced flow. Mixed convection flow is the combination of forced and natural convection flows. Mixed convection flows in a channel or duct are encountered in the Dual-Coolant Lead-Lithium (DDCL) flow for power conversion, tritium breeding and many industrial applications and engineering devices such as cooling system for electronic components and reactors. In such devices liquid-metal flow are strongly affected by a magnetic field and by a volumetric heating caused by the neutrons with the electrically conducting fluid (Smolentsev et al., 2008). Analysis on MHD flows associated with very high values of Hartmann number is important in designing of liquid metal tritium breeder coolant blanket for nuclear fusion reactor. Furthermore, because the flow characteristics of coolant with the temperature difference between wall boundary and the coolant are assumed to be different from usual turbulent MHD flow, it becomes necessary to investigate buoyancy flow at high values of Grashof number under a magnetic field for the design of an actual working system.
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A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

The two points considered at the alternate sides, of the tangents through the diameter of the circle, and then the line joining these points divides the circle in the ratio of the distances between the considered points to the points of contacts.

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Pregnancy in Chronic Arthritis: Only a Matter of Planning

Pregnancy in Chronic Arthritis: Only a Matter of Planning

Anakinra is a recombinant interleukin (IL)-1 receptor antagonist. In animal studies, no harm to the fetus has been demonstrated. The drug is considered Category B but little has been reported about its safety in this setting (Table 2). Tocilizumab is a monoclonal antibody directed against IL-6 receptors and capable of blocking downstream signalling. The drug is considered Category C and no teratogenicity has been demonstrated in animal models, although at high dose there was increased risk of abortion (Table 2). Abatacept works by blocking interactions between antigen- presenting cells and T cells via binding to CD80/ CD86 on antigen-presenting cells, with subsequent inhibition of T cell activation. The drug is considered Category C and there are inadequate data to fully comment on its safety during pregnancy (Table 2), although animal studies saw no increased risk when exposed to the maximum recommended human dose. Current recommendations are to discontinue therapy at least 10 weeks before conception. Rituximab, a monoclonal antibody directed against CD20, depletes B cells. Animal studies are limited but show no teratogenic efect, although B cells have been demonstrated to be reduced in ofspring. 60
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Mixed Convection Heat Transfer Enhancement in a Vented Cavity Filled with a Nanofluid

Mixed Convection Heat Transfer Enhancement in a Vented Cavity Filled with a Nanofluid

In the case of the suction mode, the effect of the Reynolds number on the dynamical and thermal fields is illustrated in Figs. 4a-4d, by presenting the streamlines and isotherms for  = 0 and  = 0.1. For Re = 100 (Fig. 4a), the streamlines show a big trigonometric cell, due to shear effect, occupying almost the left half part of the cavity and adjacent with the forced flow lines. This cell is more intense compared to the case of the injection mode (Fig. 3a). The corresponding isotherms are more tightened at the level of the heated vertical wall indicating a better convective heat transfer. Also, a big part of the cavity is at a uniform cold temperature. It is to note that this cold zone is comparable to that observed in the injection mode. By increasing Re to 500 (Fig. 4b), the streamlines show the formation of a clockwise small secondary cell in the left bottom corner and the reduction of the large cell whereas the isotherms illustrate an decrease of the cold zone in favor of the thermal boundary layer testifying of the growing effect of the mixed convection. Dynamical and thermal structures displayed in Figs. 4c-4d correspond to values of the Reynolds number of 1000 and 5000 respectively. It is seen clearly that, on the left of the curved lines, the forced convection favors the secondary cell to detriment of the big one. Moreover, the forced flow favors the formation of another clockwise cell located in the right top corner. It is to underline that even for large values of Re, the open lines of the forced convection remain curved near the hot wall. Hence, it can be deduced that the effect of the suction mode is thermally stronger and dynamically weaker when compared to the injection mode.
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Combined Thermal Radiation and Mixed Convection in an Inclined Circular Duct

Combined Thermal Radiation and Mixed Convection in an Inclined Circular Duct

Concerning the interaction between radiative and convective heat transfer for laminar flow, studies have been conducted numerically and experimentally for the two boundary conditions. Seo et al. [17] have considered a laminar flow of mixture of carbon dioxide, water vapor and nitrogen inside a circular tube with UWT. They concluded that the convective heat fluxes in combined heat transfer are greater than heat fluxes for pure convection. The heat transfer characteristics of non gray gas mixture strongly depend on the molar fraction of gases. In fact, a small amount of radiating gases can change the heat transfer significantly. Sediki et al. [2,3] investigated the interaction between the 2-D thermal radiation and convection for laminar absorbing-emitting real gases flowing inside circular duct. The radiative properties of the flowing gases were modeled by using the global Absorption Distribution Function model (ADF). They conclude that the effects of the radiative axial component remain noticeable as long as the difference between wall and fluid bulk temperatures is significant.
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SOCIAL ECONOMY – A FORM OF INCLUSION AND OF ''REACTIVATING'' OF LABOR IN THE CONTEXT OF THE CURRENT CRISIS

SOCIAL ECONOMY – A FORM OF INCLUSION AND OF ''REACTIVATING'' OF LABOR IN THE CONTEXT OF THE CURRENT CRISIS

The essence of social economy is the inclusive function of the labor market through which the different forms of social economy that exist in the member states can play a role in the overcoming the crisis, especially in the creating of jobs, including in social services field Opinion of the European Economic and Social Committee on the post‐ 2010 Lisbon Strategy 9, p. .

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Simulation of Flow and Heat Transfer of Nanofluid in an Eccentric Annulus with Multicomponent Lattice Boltzmann Method

Simulation of Flow and Heat Transfer of Nanofluid in an Eccentric Annulus with Multicomponent Lattice Boltzmann Method

journal bearing. Recently with the development of technology, the demand for energy has increased worldwide. Hence, the researchers constantly look for new methods to increase the thermal performance of different systems. Using liquid dispersion of solid nanoparticles (nanofluids) is a recent method that enhances thermal performance relative to traditional fluids such as water, oil or ethylene glycol. This novel technique was first introduced by Choi (1995) in order to develop advanced heat transfer fluids. Afterwards, many researchers investigated the effects of nanofluids on the forced convection heat transfer. They proved that the nanoparticles suspensions are more likely to enhance the heat transfer (Trisaksri and Wongwises 2007,Wang and Mujumdar 2007, Wen et al. 2009, Saidur et al. (2011), Fan and Wang (2011), Sarkar (2011)). On the other hand, relatively few works have been performed on natural or mixed convection heat transfer in nanofluids especially in annulus. As regards the convective flow of nanofluids in annulus, Abu- Nada et al. (2008) numerically studied the natural convection of nanofluids in a concentric annulus. They presented the effect of nanoparticles on heat transfer in the various ranges of Rayleigh number and nanoparticles volume fraction. Cianfrini et al. (2011) theoretically conducted the natural convection heat transfer of nanofluid flow in horizontal concentric cylinders maintained at different uniform temperatures. The results revealed that increasing nanoparticle volume fraction, increases the heat transfer coefficient and the highest heat transfer rate relates to the smallest nanoparticles size. Natural convection of copper- water nanofluid in a vertical annulus channel was numerically investigated by Shahi et al. (2011). They showed that the Nusselt number increases as nanofluids concentration increases. Habibi and Pop (2013) conducted a numerical study of the natural heat transfer to Cu-water nanofluid flow in a horizontal eccentric cylinder. They examined the effect of eccentricity and volume fraction of nanoparticles on the Nusselt number. Their results are in good agreement with previous investigations. Ashorynejad et al. (2012) and Parvin et al. (2012) investigated the natural convection of nanofluids in a concentric annulus by considering the magnetic field effects and the thermal conductivity variations. Also, the transient natural convection heat transfer of aqueous nanofluids in a horizontal concentric annulus has been studied by Yu et al. (2012).
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Magneto-Thermosolutal Convection in Maxwellian Dusty Viscoelastic Fluid through Porous Medium

Magneto-Thermosolutal Convection in Maxwellian Dusty Viscoelastic Fluid through Porous Medium

The study of onset of convection in a porous medium has attracted considerable interest because of its natural occurrence and of its intrinsic importance in many industrial problems, particularly in petroleum-exploration, chemical and nuclear industries. The derivation of the basic equations of a layer of fluid heated from below in porous medium, using Boussinesq approximation, has been given by Joseph [1]. The study of a layer of fluid heated from below in porous media is motivated both theoretically and by its practical applications in engineering disciplines. Among the applications in engineering disciplines one can find the food process industry, chemical process industry, solidification and centrifugal casting of metals. The development of geothermal power resources has increased general interest in the properties of convection in porous medium. Lapwood [2] has studied the stability of convective flow in a porous medium using Ra yleigh’s procedure. The Rayleigh instability of a thermal boundary layer in flow through a porous medium has been considered by Wooding [3].
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SIMULTANEOUS THERMAL AND MASS DIFFUSION IN MHD MIXED CONVECTION FLOW

SIMULTANEOUS THERMAL AND MASS DIFFUSION IN MHD MIXED CONVECTION FLOW

awareness, the effect of ohmic heating on the MHD free convection heat transfer has been examined for a Newtonian fluid by Hossain [14]. Chen [15] studied the problem of combined heat and mass transfer of an electrically conducting fluid in MHD natural convection, adjacent to a vertical surface with ohmic heating. The propagation of thermal energy through mercury and electrolytic solution in the presence of magnetic field and radiation has wide range of applications.

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Experimental investigation in thermal conductivity of CuO and ethylene glycol nanofluid in serpentine shaped microchannel

Experimental investigation in thermal conductivity of CuO and ethylene glycol nanofluid in serpentine shaped microchannel

Steinke and Kandlikar [17] presented a comprehensive review of friction factor data in microchannels with liquid flows. They indicated that entrance and exit losses need to be accounted for while presenting overall friction factors losses in microchannels. Most of the data that accounted for friction factor loss show good agreement with the conventional theory. They also provided a new procedure for correcting measured pressure drop to account for inlet and outlet losses. The three-dimensional fluid flow and heat transfer phenomena inside heated microchannels were investigated by Toh et al. [18]. They solved the steady laminar flow and heat transfer equations using a finite-volume method. It was found that the heat input lowers the frictional losses and viscosity leading to an increase in the temperature of the water, particularly at lower Reynolds numbers. Peng and Peterson [19,20] performed experimental investigations on the pressure drop and convective heat transfer of water flow in rectangular microchannels. They found that the cross sectional aspect ratio had a great influence on the flow friction and convective heat transfer both in laminar and turbulent flows. Tiselj et al. [21] performed experimental and numerical analysis of the effect of axial conduction on the heat transfer in triangular microchannel heat sink. They pointed out that the bulk water and heated wall temperatures did not change linearly along the channel.
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The Influence Of CSR Awareness On Consumer Purchase Decision Of A Telecommunication Network In Ghana A Case Of La Nkwantanag Madina Municipality

The Influence Of CSR Awareness On Consumer Purchase Decision Of A Telecommunication Network In Ghana A Case Of La Nkwantanag Madina Municipality

on overall company evaluations‖. Murray and Vogel (1997) have investigated the effect of associated CSR practices on consumers and presented similar findings. The CSR activities mentioned in the research are, for instance, environmental protection practices (energy conservation), engagement in acts to promote human welfare, corporate social marketing (electric safety education for schoolchildren), contribution to the economic development of the region, and consumer protection program. Their research found that CSR programs lead to improved customer attitudes towards the firm, including beliefs about the company‘s honesty, consumer responses, and increased support for the firm in labor or government disputes. Mohr et al. (2001) conducted a consumer interview project for investigating the impact of firms‘ CSR on consumer behavior. How well are consumers aware of the CSR level of individual firms? Are the purchase decisions of consumers affected by a firm‘s CSR, and how much? How do consumers think about firms‘ motivation for being socially responsible? Mohr et al. (2001) found that consumers are positive to business in general. It is not wrong to pursue economic interests. Consumers expect firms to be socially responsible. The attitudes of consumers toward socially responsible firms are more positive than toward irresponsible firms. Consumers are aware that socially responsible firms are helping themselves by practicing CSR. But this perception of consumers does not harm the positive consumer evaluations toward socially responsible firms. The study of Mohr et al. (2001) is enlightening for researchers, managers and policy makers. For managers specifically, it is clear that consumers do care about a firm‘s CSR and act accordingly. Some consumers are highly ethical in
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A Review Of Fault Tolerant Scheduling In Multicore Systems

A Review Of Fault Tolerant Scheduling In Multicore Systems

assignments task on the cores and tolerate processing component failures which could either be rogeneous or heterogeneous. The heterogeneity of the processors implies that they have diverse velocities or transforming abilities. The transient flaw likelihood that may happen in transistors, entryways and even a bit, is called Architectural helplessness variable (AVF) [5]. By averaging over some time, this component can characterize the rate of soft errors that can show up on a core; while it runs a task. This algorithm when compared with other techniques we found that the proposed fault tolerant method outflanks both TMR and DMR methods about 35% in average. In computing most common topologies in N-Modulo Redundancy are TMR and DMR. TMR method is used when reliability of task is important as it can only mask the faults. The problem is that voter can also be faulty. The other method DMR includes two cores running parallel and checks for the similarity in the output thus only indicate the mismatch doesn’t tolerate the fault so have to use separate mechanism for fault recovery [5]. In software based fault tolerance based approach replica of process are used so it is necessary that replicas use same memory addresses. We also need to ensure that leader and follower use same replica copies. Replica can be created using fork system call in which process generates same process as follower process and it works same as leader process. If the result of both leader and follower process is same then we can say that there is no error. But if there is difference between leader and follower process then error is there. We can use check points for efficiency. If after execution of leader and follower process result is same then previous checkpoint is eliminated and if result
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Investigation of sintering in electroceramics by thermodilatometry

Investigation of sintering in electroceramics by thermodilatometry

Sintering is a high-temperature technological process that transforms individual ceramic particles into a compact polycrystalline body. This process is widely used to fabricate bulk ceramic components [1, 2]. The driving force of the sintering process is an excess of the free energy associated with the large free surface of an agglomerate of fine powder particles. During solid-state sintering powder particles are welded to their neighbors, junctions between them are gradually increased with time, and the internal free surface of the powder compact is decreased [2, 3]. Sintering is accompanied by the vanishing of the porosity, which is connected with shrinkage of the sample measurable by dilatometer.
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Transient MHD Free Convective Flow of an Optically Thick Gray Gas Past a Moving Vertical Plate in the Presence of Thermal Radiation and Mass Diffusion

Transient MHD Free Convective Flow of an Optically Thick Gray Gas Past a Moving Vertical Plate in the Presence of Thermal Radiation and Mass Diffusion

growth. Until recently this study has been largely concerned with flow and heat transfer characteristics in various physical situations. Radiative magnetohydrodynamic flows arise in many areas of technology and applied physics including oxide melt materials processing (Shu et al. (2004)), astrophysical fluid dynamics (Stone and Norman (1992); Vishwakarma et al. (1987)), plasma flow switch performance (Bowers et al. (1990)), MHD energy pumps operating at very high temperatures (Biberman et al.(1979)) and hypersonic aerodynamics (Ram and Pandey (1980)). Takhar et al. (1996) investigated the effects of radiation on the MHD free convection flow of radiating gas past a semi-infinite vertical plate. Raptis and Masslas (1998) studied unsteady magnetohydrodynamics convection in a gray, absorbing- emitting but non-scattering fluid regime using the Rosseland radiation model. A similar study was communicated by Raptis and Perdikis(2000). Azzam (2002) considered thermal radiation flux influence on hydromagnetic mixed convective steady optically-thick laminar boundary layer flow also using Rosseland approximation. Helliwell and Mosa (1979) reported on thermal radiation effects in buoyancy-driven hydromagnetic flow in a horizontal channel flow with an axial temperature gradient in the presence of Joule and Viscous heating. Yasar and Moses (1992) developed a
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Investigation of Compacting and Adhesion of Plastic Materials on a Vertical Plane by Means of Vibration

Investigation of Compacting and Adhesion of Plastic Materials on a Vertical Plane by Means of Vibration

The results obtained by us and described in numerous scientific literature show that in condition of stressed (Fig.7) muscles (in models of increased bounces) the vibration is circulated very intensively and it should be noted that the peaks of circulated amplitudes do not decrease. For human health aforesaid condition is very undesirable while the slacked (fig.6) muscle (the model of lower bounces) decreases the peaks of dynamic loads significantly. So it is very desirable and necessary that the men were released from holding the vibratory devices for a long time. When the operator presses the vibratory devices only (do not holding it in hands) by fingers it (Fig. 8) is less dangerous than holding it in the hands exercising technological operations in that condition. So, it is reasonable to create special adjustments by means of which the operator becomes free from holding the vibratory devices in hands.
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Oscillatory Magnetohydrodynamic Natural Convection of Liquid Metal between Vertical Coaxial Cylinders

Oscillatory Magnetohydrodynamic Natural Convection of Liquid Metal between Vertical Coaxial Cylinders

The numerical investigation of the effect of radial or axial magnetic field on the double-diffusive convection in a cylindrical annular cavity by solving the complete Navier–Stokes equations for a wide range of physical parameters are carried out by Venkatachalappa et al. (2011). Heat and mass transfer, fluid flow results are presented in terms of streamlines, isotherms, average Nusselt and Sherwood numbers. For small buoyancy ratios, the magnetic field suppresses the double-diffusive convection, and it is effective when it is applied perpendicular to the main flow. Fattahi et al. (2010) simulated natural convection in eccentric annulus using the Lattice Boltzmann Model, in order to examine the effect of diagonal, vertical, and horizontal eccentricity at various locations on the convection. Their results showed that Nusselt number increases with lowering the inner cylinder independent of its radial position. Witkowski and Walker (2002) studied numerically the steady liquid metal flow between a pair of insulated cylinders subjected to a rotational motion and a uniform weak transverse magnetic field. The main flow pattern consisted of an axisymmetric part combined with a weak nonaxisymmetric part. Kumar and Kalam (1991) reported numerically generated heat transfer data for laminar natural convection in tall and short vertical annuli with isothermal vertical cylinders. In the present work, a similar configuration for that use by Sankar et al. (2006) is considered where a liquid metal is placed inside two concentric vertical cylinders. Thus, heat transfer, MHD stability effects may be significantly different when in change of the aspect ratio. The effect of the magnetic field orientations, aspect ratio and thermal condition of the inner and outer cylinders on the stability of the flow is investigated. To our knowledge the MHD stability controlled with an aspect ratio of enclosure and the magnetic field directions in cylindrical annulus has never been the object of a preceding study, except thus studied by Mebarek-Oudina and Bessaih (2014a) in a cylindrical configuration and for the laminar case by Sankar et al. (2006).Our objective is to determine the critical Rayleigh numbers, Ra cr associated with Hartmann numbers
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Effects of chemical reaction in thermal and mass diffusion of micropolar fluid saturated in porous regime with radiation and ohmic heating

Effects of chemical reaction in thermal and mass diffusion of micropolar fluid saturated in porous regime with radiation and ohmic heating

When the temperature of surrounding fluid is high, the radiation effects play an im- portant role that cannot be ignored, Modest [28] and Siegel and Howell [29]. The effects of radiation on temperature have become more important industrialized. Many processes in en- gineering areas occur at high temperature and acknowledge radiation heat transfer become very important for the design of pertinent equipment. Nuclear power plants, gas turbines and the various propulsion devices for aircraft, missiles, satellites and space vehicles are examples of such engineering areas. In such cases one has to take into account the effects of radiation and free convection. For an impulsively started infinite vertical isothermal plate, Ganesan et al. [30] studied the effects of radiation and free convection, by using Rosseland approxima- tion, Brewster [31]. Problem of radiative heat transfer with hydromagnetic flow and viscous dissipation over a stretching surface in the presence of variable heat flux is solved analytically by Kumar [32]. Hossain and Takhar [33], Raptis and Massals [34], and Hossain et al. [35] studied the radiation effect on free and forced convection flows past a vertical plate, including various physical aspects. Aboeldahab Emad [36] studied the radiation effect on heat transfer in an electrically conducting fluid at the stretching surface. At high operating temperature, ra- diation effect can be quite significant, Ghaly and Elbarbary [37]. Heat and mass transfer ef- fects on moving plate in the presence of thermal radiation have been studied by Muthucuma- raswamy and Kumar [38] using Laplace technique. For the problem of coupled heat and mass transfer in MHD free convection, the effect of both viscous dissipation and ohmic heating are not studied in the previous investigations. However, it is more realistic to include these two effects to explore the impact of the magnetic field on the thermal transport in the boundary layer. With this awareness, the effect of ohmic heating on the MHD free convection heat transfer has been examined for a Newtonian fluid by Hossain [39]. Chen [40] studied the problem of combined heat and mass transfer of an electrically conducting fluid in MHD natu- ral convection, adjacent to a vertical surface with ohmic heating.
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