Effect Of Transverse Magnetic Field Research Articles

Irreversibility estimation in triply stratified bio-marangoni convection in powell-eyring nanofluid under the influence of external flow

Due to the growing importance of bioconvection phenomena in diverse industrial processes such as oil refining, biotechnology, and food processing, it is essential to examine several effects like a chemical reaction, stratification, Marangoni convection, etc in nanofluid suspensions in the context of transport of microorganisms. The outcome of such studies may provide significant insight into controlling and as well as manipulating the transport of energy, solute, and microorganisms for achieving the requisite target. The aim of our study is to investigate the thermo-solutal Marangoni convection of gyrotactic microorganisms suspended in Powell-Eyring nanofluid in a stratified medium. This analysis also takes into account the effects of external flow and transverse magnetic field. The impact of Arrhenius activation energy, thermal radiation, and binary chemical reactions on bioconvection flow is considered under stratified Marangoni convection. Under appropriate assumptions without violating the physics, the present problem is expressed in terms of nonlinear PDEs. Some capable similarity transformations are employed to convert the PDEs into ODEs and solved numerically by the Runge-Kutta Fehlberg method. The graphical illustrations depict the effects of relevant flow parameters on temperature, nanoparticle volume fraction, and density distributions of motile microorganisms. The study focuses on understanding the variations in significant engineering quantities resulting from changes in crucial effects and analyzing irreversibilities. It is noticed that Marangoni accelerates the mass transfer process while on the other hand delaying the heat transfer and microorganisms density gradient. The dominance of Powell-Eyring nanofluid on the heat and mass transport amplified in accompanying Marangoni convection. The results indicate that the Eyring-Powell fluid significantly reduces entropy generation and the Bejan number. Conversely, an increase in entropy generation is observed for the Marangoni ratio parameter. Hence, this work provides insight into interlinked flow in bioconvective systems, with potential diverse applications in microbiological processes.

Transverse magnetic field effects on the high-voltage pulsed discharge plasma in helium

This study investigates the effect of a transverse magnetic field on high-voltage pulsed discharge in helium at a pressure of 30 Torr. A simple two-dimensional fluid model that describes the high-voltage pulsed discharge in helium in a transverse weak magnetic field (B = 0.4 T) is presented, which uses an empirical relation to account for the magnetic field. The results of using the empirical relation for the effective field agree well with the experimental results. The dynamics of discharge development in the presence of the magnetic field is also investigated. The magnetic field does not significantly affect the gas-discharge development dynamics in helium at a pressure of 30 Torr.

A wide dynamic range diamond quantum sensor as an electric vehicle battery monitor.

To demonstrate the application capability of the diamond quantum sensor as an electric vehicle (EV) battery monitor, we (i) investigated the measurable current in a real car noise level and (ii) compared the linearity with conventional sensors. Consequently, (i) we could measure a 20 mA current pulse even under an external magnetic field of 80 µT, which is larger than that of 50 µT around the EV battery module in a real car during driving. The 20 mA pulse measurement corresponds to the EV battery state of charge estimation accuracy of 0.2% in the standard driving pattern, which is smaller than the present level of 10%. (ii) The linearity degradation seen in the Hall sensor near the upper limit of the measurement range was not seen in the diamond sensor. Although the Hall sensor and the shunt resistor showed linearity degradation in the current range of several tens of amperes or less, the degradation was smaller for the diamond sensor. The transverse magnetic field effect in the diamond sensor on the linearity was estimated to be less than 0.01% for a several-degree misalignment of the sensor surface to the magnetic field direction and under a 340 A current. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'.

Effect of low magnetic field heat treatment process on grain sizes and soft magnetic properties of Finemet cores

In this study, we investigate the effect of low transverse magnetic field annealing on the soft magnetic properties of cores made of industrial Finemet ribbons. The variation of static/dynamic magnetic properties and average grain size of the cores obtained by zero-field annealing (ZFA), secondary-field annealing (SMA) and direct-field annealing (DMA) are studied in detail. It is found that the average grain size obtained by DMA decreased compared to that of the ZFA sample, while the average grain size increased slightly after SMA. The effective permeability (μe) of the ZFA sample after SMA decrease less than that of the ZFA sample with increasing frequency. The μe of the DMA sample decreases significantly at the low-frequency stage but tends to decrease smoothly overall, maintaining high effectiveness at high frequencies magnetic permeability. For example, at 100 kHz, the μe of ZFA at 550 °C temperature is only 0.6 × 104, while the μe of SMA and DMA are 2.0 × 104 and 2.2 × 104, respectively. Meanwhile, the Hc = 1.85 A/m, Br = 0.59 T after ZFA and Hc = 1.67 A/m after DMA show no significant decrease compared to ZFA. While Hc = 0.55 A/m, Br = 0.08 T after SMA. Due to the field anisotropy constant Ku generated after SMA and DMA, the average anisotropy constant is dominated by Ku, the domain structure becomes simple and uniform, and the domain width becomes larger. This leads to a decrease in core losses with increasing frequency and improves the high-frequency characteristics of the core. These results can provide good guidance for performance optimization for Finemet alloys in a wide frequency range.

Computation of EMHD ternary hybrid non-Newtonian nanofluid over a wedge embedded in a Darcy-Forchheimer porous medium with zeta potential and wall suction/injection effects

The field of engineering is witnessing an increasing number of applications for intelligent electromagnetic nano-coatings. These recent advancements serve as the impetus for an investigation into a theoretical and computational study of an unsteady electro-magneto-hydrodynamic (EMHD) incompressible two-dimensional tangent hyperbolic non-Newtonian ternary hybrid nanofluid boundary layer coating flow external to a two-dimensional porous wedge geometry adjacent to a Darcy-Forchheimer porous medium. Both aligned electrical and transverse magnetic field effects are included. The effects of zeta-potential and surface injection/suction are included. The ternary composite nanofluid comprises three nanoparticles ( A l 2 O 3 , T i O 2 and S i O 2 ) with aqueous base fluid ( H 2 O ) The governing conservation partial differential equations for continuity and momentum and associated boundary conditions at the wedge surface and free stream are transformed with appropriate similarity variables. The emerging ordinary differential nonlinear boundary value problem is numerically solved in MATLAB. Validation with earlier studies is included. A significant deceleration is induced in the flow of a ternary hybrid nanofluid with an increase in the electric field parameter. An increment in Falkner-Skan power-law constant (moving wedge angle parameter) boosts the local skin friction coefficient for both the ternary hybrid nanofluid (THNF) and unitary A l 2 O 3 nanofluid (UNF) cases. The flow is boosted with an increase in the power-law rheological characteristic, which ranges from shear-thinning n < 1 to shear-thickening n > 1.

Numerical study on the flow and heat transfer of molten salt in a horizontal pipe applied transverse magnetic field

Based on a modification of a magnetohydrodynamic turbulence model, a numerical study was performed to investigate the effects of transverse uniform and gradient magnetic field on the turbulent flow and heat transfer characteristics of a low melting point molten salt in a stainless steel pipe. With the Hartmann number from 0 to 80, the numerical results showed that the fluid flow displayed anisotropic distributions under the magnetic field with decrease of velocity in the mainstream region, and decrease of turbulent intensity, whereas the flow velocity increased in the boundary layer near the Hartmann and Roberts wall. Especially, a velocity jet phenomenon was observed in the Roberts boundary layers at higher Hartmann number in the uniform magnetic field or the positive gradient magnetic field. Under the gradient magnetic field, the flow and heat transfer of molten salt displayed much more variations than under the uniform magnetic field. The magnetohydrodynamic calculation results proposed here might be helpful to the design of the composite heat transfer system for molten salt in actual industrial applications.

Effect of transverse magnetic field on dose distributions of yttrium 90 skin patch source

The total dose absorbed on the tumor cell from the skin patch sources used in clinical superficial brachytherapy should be limited within the target tumor volume in order to minimize the potential side effects. Average range of the beta particles within tissue may exceed the thickness of a superficial skin tumor beyond the target tumor volume, causing side effects by damaging the deeper located healthy tissue and the bone underneath the tumor. It is desired to minimize the possible side effects by selecting a short-range radionuclide. Administering the treatment under an external magnetic field is another option for reducing side effects. To achieve this, in this study, the percentage deep dose (PDD) and transverse dose profile (TDP) distributions of the skin patch source labeled with Yttrium 90 (90Y) using the GEANT4-based GAMOS Monte Carlo code were examined before and after applying magnetic field, and it was evaluated whether it was possible to limit the dose within a certain volume or not.&#x0D; Simulation results showed that, along with the application of a transverse magnetic field, the dose values increased by 7.2% and 3.1% respectively at 0.25 mm and 1.0 mm depths whereas it decreased by 9.4%, 25.0%, 41.8% and 57.6%, at 2.0 mm, 3.0 mm, 4.0 mm and 5.0 mm depths respectively on the central axis from the surface of the tissue phantom with respect to the 0 T values of the field. In case of a superficial skin tumor with a thickness of 3.0 mm from the skin surface, the amount of dose accumulated in the tumor volume for 0 T value of the transverse magnetic field was 89% of the total dose, while it increased to 98% at the intensity of 1.5 T, and the dose received by the healthy tissue under the tumor decreased by 10.1%.

Effect of wall electrical conductivity and transverse magnetic field on turbulent mercury flows in nonuniformly heated pipes

Effect of wall electrical conductivity and transverse magnetic field on turbulent mercury flows in nonuniformly heated pipes

Effect of Porosity and Transverse Magnetic Field on the Wake Separation and Detachment around a Porous Square Cylinder

Effect of Porosity and Transverse Magnetic Field on the Wake Separation and Detachment around a Porous Square Cylinder

Two layer thin film flow over a stretching sheet with uniform transverse magnetic field

The objective of the present work is to study the effect of uniform transverse magnetic field on two immiscible thin liquid film flow over a linear stretching sheet. Applying similarity transformations, the guiding Navier–Stokes equations have been transformed into a system of non-linear partial differential equations, which are numerically solved by the finite difference method. The effects of the governing parameters viz. magnetic field parameter Mn, density ratio m, viscosity ratio n, thickness ratio δ and Reynolds number Re1 are analyzed in detail. It is found that the effect of varying Reynolds number is more pronounced on film thinning in presence of uniform transverse magnetic field.

Effect of generalized thermal transport on MHD free convection flows of nanofluids: A generalized Atangana-Baleanu derivative model

The purpose of this article is to analyse the influence of a the generalized thermal transport on the free convection flow of a viscous nanofluid inside a cylindrical tube. The generalized Atangana-Baleanu time-fractional differential operator is used to generalized the heat transport equation. The effect of transverse magnetic field is also considered. The close form solutions are found by use of integral transformations, more precisely Laplace and finite Hankel transformations. The graphs depict the influence of fractional and other physical characteristics. Tables illustrate the effect of the volume fraction parameter. It has found that the heat flux given by the fractional equation influence heat transfer because the values of the temperature gradient are attenuated by the weight function in the heat flux expression. The temperature in the nanofluid has a different evolution concerning the fractional parameter.

Effect of transverse magnetic field on wake dynamics and heat transfer through a porous circular cylinder

AbstractA two‐dimensional numerical simulation using the commercial computational fluid dynamics package ANSYS Fluent 15.0 is performed to investigate the effect of a transverse magnetic field on the wake dynamics around a heated porous circular cylinder. The study is conducted considering a Newtonian, incompressible, and electrically conductive fluid with constant properties for the low Reynolds number laminar regime. In the range of Reynolds number (Re = 10–40), recirculating vortices are observed to penetrate (or detach) into (from) the porous cylinder surface depending on the Darcy number, Da (10−6 to 10−2). The effect of the magnetic field parameter (Hartmann number) Ha (0–10) on the detachment and penetration characteristics of a porous cylinder is reported for the first time. A steady separated flow behind the cylinder turns into an attached flow at a critical magnetic field strength. Accordingly, the critical Hartmann number (Hacr) is estimated for the complete suppression of the flow separation behind the porous cylinder. Hacr is found to decrease with an increase in Da and a decrease in Re. The wake behind the cylinder is also found to be detached from the cylinder surface at a particular value of the magnetic field strength termed as the detachment Hartmann number (Had). Had also decreased with an increase in Da and decrease of Re. In addition, the effect of Ha on the separation angle, recirculation length, detachment length, and drag coefficient is also discussed. Furthermore, the effect of the magnetic field on the forced convective heat transfer characteristics is also studied considering various fluids (Prandtl number, Pr = 0.02, 0.71, and 7) past the circular permeable cylinder. At a particular Pr, the heat transfer rate is almost invariant for low permeability, whereas it increases significantly at higher permeability with an applied magnetic field. The rate of heat transfer increases with the Prandtl number for all Hartmann and Darcy numbers. Finally, a correlation is developed to predict the average heat transfer as a function of Re, Pr, Da, and Ha.

Signature of miniband nodes in magneto-optical properties of one-dimensional superlattice of planar quantum rings

The effect of transverse magnetic field on the band structure, magnetization and inter-miniband magnetoabsorption of a one-dimensional superlattice of planar quantum rings is discussed. The band structure calculations are made in the framework of diagonalization procedure. A complete set of basis functions, reflecting the structure periodicity in superlattice direction and the effect of magnetic field is constructed, considering the Landau gauge of the vector potential in the Hamiltonian. It is shown that the energy minibands reveal repeating nodes that correspond to a degeneration of quantum states. The magnetization of the system mimics the main peculiarities of the same quantity for a single QR, however considerable differences are observed as well. The examination of the magnetoabsorption indicates on the possibility to extract an information about the existence of nodes in the band structure and the arrangement of quantum states in the neighboring minibands.

Effect of transverse magnetic field on microstructure and mechanical properties of Ti-6Al-4 V manufactured by Laser-MIG hybrid welding

In this study, an external transverse magnetic field was used to assist laser-metal inert gas (MIG) hybrid welding of Ti-6Al-4 V (TC4). The microstructure and mechanical properties, such as microhardness and tensile properties of the weld joints, under an external magnetic field (EMF) and a reference weld joint without the EMF were investigated. The results showed that the laser-arc interaction zone (LAIZ) and heat-affected zone (HAZ) expanded, and the laser fusion zone (LFZ) and fusion zone (FZ) changed with the application of the EMF, resulting in a change in the distribution of microhardness. The microstructure of the FZ was comprised of Widmanstatten α′-grains and primary boundary β-grains without the EMF. After applying the EMF, the diameter of the primary globular β-grains in the FZ decreased by 38.6%, from 78.4 to 48.1 μm, and a small amount of residual dot-like β-grains appeared in the FZ of the joint. The mechanical properties of the weld seam improved significantly under the EMF; the average microhardness in the FZ increased by 9.7%, and the failure strain and stress of the tensile specimens improved by 45.6% and 6.6%, respectively, owing to the solid solution strengthening of the residual dot-like β-grains and finer primary β-grain boundary. In addition, a mixed fracture mode was observed on the fracture surfaces. This study revealed that the elementary microstructure of laser-MIG hybrid welded TC4 was correlated with the welding heat input of the EMF.

Investigation of magnetorheological grease flow under the influence of a magnetic field

In this work, we present a novel magnetohydrodynamic flow study using micro-Particle Image Velocimetry (m-PIV) in a rectangular channel under the effect of a uniform transverse magnetic field. This study is the first of its kind to explore the use of magnetorheological grease in machine components such as bearings. Rheological characterisation of grease samples establishes the non-linear relationship between the shear rate and shear stress and thus confirms the non-Newtonian behaviour of the grease. The flow follows a parabolic path away from the magnetic field. Experimental studies reveal that the flow velocities reduce considerably from 11.9 m/s to 1.7 m/s in the vicinity of the magnetic zone due to the formation of strong field-induced chains. These chains are responsible for an increase in localized yield stress of grease thereby causing a surge in the resistance to flow. Further, numerical and analytical models are developed to predict the velocity field under a magnetic field. The analytical model can accurately predict the flow velocity for different magnetic field strengths. It can be deduced that the obtained correlation is a suitable model for estimating the velocity values at different magnetic field strengths for flow in similar configurations. Numerical results predicted by a finite volume method-based solver are in good agreement with the experiments on the upstream side. Flow velocities increase with flow rate and decrease with the onset of the magnetic field. Pressure drop along the channel length shows an abrupt change in the magnetic zone. This is because of the disturbance of the normal flow regime due to the presence of the magnetic field. The grease flow disturbs the distribution of magnetic field lines resulting in flow-induced field strength of B = 0.1 T against an applied external magnetic field strength value of B = 0.3 T. The present study analyses the effects of an external field on the flow patterns of magnetorheological grease. It confirms that magnetorheological grease provides controllability in applications, because flow properties can be varied by tuning the magnetic field strength.

Transverse Magnetic Field Effect on Extracellular Fluid Flow along with a Semi-Infinite Vertical Rotating Porous Plate

The primary intention of this practice is to numerically investigate the extracellular fluid (ECF) flow for unsteady 2-dimenstional case along with a porous vertical plate with the appearance of a transverse magnetic field in a rotating system. The dimensional basic equations have been non-dimensionalized by necessary dimensionless variables. The EFDM has been practiced to solve the dimensionless equations. The numerical data have been evaluated by FORTRAN software version 6.6a. For a perfect conductivity, Magnetic Diffusivity Number values have been taken between 5 to 15 in the induction formula. For proper exactness, stability and convergence tests have been performed. For initial time , the outputs have been illustrated for the primary, secondary and angular velocity, primary and secondary induced magnetic field, temperature field with shear stresses for and -direction, couple stress for -direction, and -direction current densities and Nusselt number. Finally, the outcomes of different parameters are discussed separately and pictorial graphically by MATLAB R2018a.The findings of this research may be used to control cell temperature, measurement of extracellular fluid motion, and so on.

Combined effect of transverse electric and magnetic fields on THz generation by beating of two amplitude-modulated laser beams in the collisional plasma

Combined effect of transverse electric and magnetic fields on THz generation by beating of two amplitude-modulated laser beams in the collisional plasma

Study of coupling effects on the three-dimensional magnetohydrodynamic flows around single and tandem cylinders in duct

This work focuses on magnetohydrodynamic (MHD) flow around either single or two identical tandem circular cylinders confined in a duct under external transverse magnetic field. The influences of transverse magnetic field, inlet velocity of conducting fluid, and the distance between two cylinders arranged along the flow direction on the flow modes, vortex shedding frequency, separation angle, and drag coefficient are investigated. The simulations are conducted with the Hartmann number Ha and Reynolds number Re and are varied from 0 to 1.35 and from 100 to 200, respectively. For the MHD flow around single cylinder, the map of flow instability is set up and the relation between critical Hartmann number Hacr and Re is concluded as The coupling effect of geometry confinement and external transverse magnetic field can increase the separation angles and drag coefficients and decrease vortex shedding frequencies and lengths of reverse flow. For the tandem double cylinder cases, the spacing ratio between two cylinders L/d changes from 2 to 8. The boundary between steady regime and unsteady regime is described as, The three wake patterns are found under various magnetic fields. The nonlinear and nonmonotonous characteristics of coupling effects of Ha, Re, and L/d are summarized. The physical mechanisms of influences of MHD flow field in gap region between tandem cylinders and the existence of upstream cylinder on flow instability and wake pattern are revealed. Finally, the critical conditions corresponding to the transition from steady flow to unsteady flow are achieved with formulas.

Effect of transverse magnetic fields on the flow and heat transfer characteristics of magnetogasdynamic flows in circular tubes

To address the issue of the thermal energy control of high-temperature conductive gases in circular tubes, a new method to regulate the flow and heat transfer by utilizing a transverse magnetic field (TMF) to act on magnetogasdynamic (MGD) flows is proposed. Considering the characteristics of the insufficient development of turbulence at the tube inlet, this study investigated the effects of magnetization range, magnetic transition gradients, Reynolds number (9612 ≤ Re ≤ 40050), and Hartmann number (0 ≤ Ha ≤ 740) on MGD flow in a circular tube under the action of a TMF by applying numerical simulations. The results demonstrated that the MGD flow and heat transfer in a circular tube are anisotropic under an applied TMF, and this behavior becomes increasingly evident with increasing Re and Ha. Moreover, the action of an applied TMF suppresses the overall heat transfer at the tube wall, but the effect exhibits saturation with increasing Ha. In addition, the above suppression effect increases with increasing Re, but the required value of Ha also increases with increasing Re. Finally, within regions that include a magnetic field gradient, symmetric high-speed zones appear near the Roberts boundary layer, and the heat transfer intersity is enhanced in these regions. This enhancement is positively correlated with the magnitude of the magnetic field gradient. The analysis presented herein provides a new and comprehensive means for utilizing magnetic fields to control the thermal energy of MGD flows in circular tubes.

Excitonic condensation and metal-semiconductor transition in AA bilayer graphene in an external magnetic field

In this paper, the effects of the external transverse magnetic field $B$ (perpendicular to the surface of the layers) on the electronic and excitonic properties are studied in the AA-stacked bilayer graphene (BLG). The effects of the Coulomb interactions and excitonic pairing have been taken into account and analyzed in detail within the bilayer Hubbard model. Both half-filling and partial filling regimes have been taken into account and the magnetic field dependence of a series of physical parameters was found. It is shown that the difference between the average electron concentrations in the layers vanishes at some critical value of magnetic field $B_{c}$ and the chemical potential is calculated numerically above and below that value. The role of the Coulomb interactions on the average carrier concentrations in the layers has been analyzed, and the excitonic order parameters have been calculated for different spin orientations. We found a possibility for the particle population inversion between the layers when varying the external magnetic field. The calculated electronic band structure in the AA-BLG shows the presence of metal-semiconductor transition, governed by the strength of the applied magnetic field or the interlayer interaction potential. We show that for high magnetic fields the band-gap is approaching the typical values of the gaps in the usual semiconductors. It is demonstrated that, at some parameter regimes, the AA-BLG behaves like a spin-valve device, by permitting the electron transport with only one spin direction. All calculations have been performed at the zero-temperature limit.