Combined Effects Of Magnetic Field Research Articles

Numerical Study of Chemical Reaction and Magnetic Field Effects on MHD Boundary Layer Flow over a Flat Plate

This investigation explores the combined effects of magnetic fields and chemical reactions on the movement of a boundary layer toward a flat plate. The study considers the influence of viscous dissipation on the energy distribution. By utilizing partial differential equations (PDEs), the flow phenomenon is modeled. Through the application of suitable similarity transformations, the system of PDEs is transformed into a system of total differential equations. These modified equations are then solved using the spectral homotopy analysis method (SHAM), which incorporates the combination of the CSCM and HAM procedures. The analysis reveals that magnetohydrodynamic (MHD) fluxes generate a Lorentz force, and a higher magnetic parameter intensifies this effect, resulting in a flattened velocity profile. Furthermore, the velocity profile improves with an increase in the chemical interaction variable. The study also shows that as the Eckert number increases, the ambient temperature of the dense dissipative fluid rises. The findings have potential applications in various engineering fields, such as petroleum pipeline flow improvement. The spectral homotopy method used in this study offers a numerical solution for analyzing the problem. The results contribute to the understanding of heat and mass transfer phenomena and can guide future research in this area.

Combined effects of magnetic field and surface treatments consisting of shot peening, plasma nitriding and their consecutive application on the friction and wear behavior of a ferromagnetic steel

Machine elements are subjected to electrical and/or magnetic field in their use and this can cause the failure of them. On the other hand, in order to extend their service life, different surface treatments such as shot peening and plasma nitriding are used. In recent years, the sequential application of these treatments has gained more attention because plasma nitriding efficiency is improved and more durable surfaces can be obtained through this method. Surface treated materials are also operated under magnetic field but their tribological performance under magnetic field is still unknown. Understanding the impact of magnetic field and surface treatments on the friction and wear behavior of the materials is the aim of the current investigation. As part of this effort, shot peening operations were performed on AISI 4140 low-alloy steel at the intensities of 16 A, 20 A and 24 A and plasma nitriding were performed at 500 °C for 1 h and 4 h. The reciprocating pin-on-disc wear tests were performed with and without magnetic field application. XRD, SEM, microhardness tester and 3D optical microscope were used for the characterization of the samples. Plasma nitriding, shot peening, and their consecutive application increased the material's wear resistance. Magnetic field application provided further enhancement in wear resistance, as the surfaces of the samples were oxidized and the particles formed during the sliding were removed from the wear zone. Untreated and shot peened samples exhibited adhesive wear, whereas abrasive wear was also observed in plasma nitrided samples. Magnetic field did not change the wear mechanisms of the samples. However, due to surface oxidation and removal of the particles, narrower wear marks were observed in the samples worn under magnetic field compared with the wear marks obtained without applying magnetic field.

Dual Solutions and Stability Analysis for Buongiorno Model of Magnetohydrodynamics Nanofluid Flow Past a Heated Shrinking Slippery Surface

This study investigates the combined effects of magnetic field, Joule heating, viscous dissipation, thermophoresis, and Brownian motion towards a convectively heated shrinking and slippery surface on a stagnation point flow of nanofluid is theoretically examined. The modified Buongiorno model for nanofluid flow is employed and numerically solved using a shooting technique together with the Runge-Kutta-Fehlberg integration scheme. It is found that dual solutions appear in certain range of shrinking surface parameter. The temporal stability analysis of the dual solutions to small disturbances was performed and the upper solution branch is found to be a stable and physically realistic solution to the problem. Appropriate results showing the influence of magnetic field, Surface slipperiness, Eckert number, Biot number, Brownian motion, and thermophoresis parameters on the nanofluid temperature, velocity, nanoparticles concentration, Nusselt number, skin friction, and Sherwood number are quantitatively discussed, and depicted graphically and in tables.

Thermal performance and SVM-based regression of natural convection in a 3D cavity filled with nanofluids as two phase mixture under combined effects of magnetic field and inner conductive hollow rotating conic object

In this study, a conductive hollow rotating conic object (H-RCO) is developed for convection control and thermal management in a 3D partially heated enclosure under uniform magnetic field with nanofluid considering two phase mixture formulation. Analysis is conducted for different parameters of interest as: Rayleigh number (Ra between 104 and 106), angular rotational speed of the H-RCO (Ω between −60 and 60), Hartmann number (Ha between 0 and 50), expansion ratio (r1 between 1.1 and 2.5) and conductivity ratio (KR between 0.01 and 50). The rotational speed and expansion ratio of the object contributes significantly to the overall performance improvements. At the highest speed of the H-RCO, the average Nusselt number (Nu) rises up to 38% when compared to cases of non-rotating object. When object with highest expansion ratio is used at rotational speed of Ω=−40, the average Nu rises by about 36%. The impacts of using magnetic field on the reduction of convective effects are stronger when rotations are active while up to 69% reduction of average Nu is seen at the highest strength. Thermal conductivity of the object at higher speeds contributes slightly to the overall heat transfer. Support vector machine based regression model is used for thermal performance predictions while model with third order polynomial kernel gives the best results as compared to high fidelity 3D computational results.

Stagnation point flow of power-law fluid in unsteady 3D boundary layer over a moving surfaces

Here, unsteady boundary layer flow under the action of magnetic effect over a moving stagnation surface has been investigated numerically. This study examines non-Newtonian fluid flow with respect to combined effect of magnetic field, movement of surface and time. Governing equations are dimensionless by applying nondimensional quantities. Then system of coupled ordinary differential equations are obtained by appropriate similarly transformations, in terms of the governing parameter including unsteady parameter ([Formula: see text], magnetic number ([Formula: see text], power-law index ([Formula: see text] and three-dimensional parameter ([Formula: see text]. Thus, the obtained modelled equations are solved numerically by the shooting technique. The problem’s parameters are thoroughly discussed and verified physically and graphically. The obtained results validate to literature result. The two relevant flows’ velocity profile’s numerical results have been examined.

Study of the combined effect of magnetic field and the addition of new composition on the rheological parameters of high paraffin oil

The article is dedicated to the study of separate and joint impact of the magnetic field and the addition of newly prepared composition on the rheological properties of high-paraffin emulsion oil. The new composition has been prepared in a 1:1 ratio of Difron-4201 to BAF-1 reagents under laboratory conditions. The sample taken from well number 208 of the SOCAR oil field has been used as high paraffin oil. Separate and joint impact of the magnetic field and composition on the freezing temperature, effective viscosity and amount of asphaltene-resin-paraffin deposits of high-paraffin oil has been studied. It has been determined that the joint impact of the magnetic field and the addition of composition on all three parameters is more effective that the use of a separate impact. Thus, the separate action of magnetic field and composition resulted in reducing the oil freezing temperature from +170С to +40C and +20C, respectively, while the freezing temperature of oil drops to –20C under the joint impact. The effective viscosity of oil under the impact of the magnetic field is 0.66 Pas; it is 0.44 Pas under the impact of the addition of composition; and it is equal to 0.003 Pas under the joint impact. The separate and combined impact of the magnetic field and the composition addition on the amount of paraffin deposits have been studied by "coldfinger test" method. It has been determined that the effect of the magnetic field on paraffin deposits accumulated on the surface of the coldfinger test is 52%, the effect of the composition addition is 74%, and the effect of the combined impact is 90%.

Influence of magnetic-pulse treatment on wear resistance of machine parts

The purpose of the study is: the impact of magnetic pulse processing on the performance properties - wear resistance and durability of parts of various units, machines, complexes. Method: the method is based on the use of the combined effect of magnetic fields on a mechanical engineering structure. The behavior of parts under the influence of strong magnetic fields is described. Result: the main advantages of the behavior of the processed material when exposed to a magnetic flux are determined. Conclusion: the use of magnetic influence on structural materials is considered a progressive method, which provides a number of advantages compared to other influences. This method allows you to change the structure of the metal itself, and therefore its physical and mechanical properties, which allows you to improve the performance characteristics of not only parts, but also the product as a whole.

Study of Microstructure and Properties of AZ91 Magnesium Alloy Welded Joint with Magnetic Field and TiO2 Activated Flux

In order to improve the weldability and bearing capacity of AZ91 magnesium alloy welded joints, magnetic field and active flux were added in the TIG welding process. In the welding process, the magnetic field and welding parameters were unchanged, and the coating amount of active flux was adjusted. The formability, mechanical properties, and microstructure of the welded joints under different coating amounts of activated flux were analyzed, and the crystallization nucleation characteristics of molten pool were discussed. The experimental results reveal that the combined effect of the magnetic field and activated flux has a significant effect on increasing the penetration and promoting mechanical properties. When the coating amount of activated flux is 3 mg/cm2, the highest penetration of the welded joint is obtained, which is 141% of that without activated flux. Meanwhile, the mechanical properties reach the maximum, which is a tensile strength of 292 MPa, elongation of 11.2%, and weld zone hardness of 75.6 HV (0.5 Kgf). The combined effect of TiO2 flux and magnetic field does not change the phase composition and the grain orientation of a weld metal but can affect the grain size. The average grain size of a weld metal under an activated flux coating amount of 3 mg/cm2 is 18.2% smaller than that under an activated flux coating amount of 1 mg/cm2.

Similarity solutions for a magnetized supercritical accretion disc around a rotating object

ABSTRACT The effect of toroidal magnetic fields on a supercritical accretion disc (slim disc) around a rotating object is examined. In this research, it is supposed that angular momentum transport is due to viscous turbulence and the α-prescription is used for the kinematic coefficient of viscosity. Moreover, the general relativistic effects are neglected. The degree of advection that demonstrates the fraction of energy that accretes by matter on to the central object is considered by f parameter. For the steady-state structure of such accretion flows, a set of self-similar solution is presented. Our solutions will include two important non-dimensional parameters β and a. β is the ratio of the magnetic pressure to the gas pressure, the so-called friction of magnetic pressure, which shows the magnetic field strength. The ratio of the angular velocities of the central body and the accretion flow is indicated by the rotating parameter a. The possible combined effects of magnetic field, spin of central object, and degree of advection are investigated. We also show the effect of rotating parameter a on the physical quantities of disc is different for co-rotating and counter-rotating flows. Moreover, by increasing the degree of advection and strength of magnetic field, the behaviour of the radial and angular velocities becomes reversed with respect to a. The model implies that the surface temperature, thickness, and luminosity of disc strongly depend on rotation parameter and strength of magnetic field.

Different effects of magnetic field on drug activity in human uterine sarcoma cell lines MES-SA and MES-SA/Dx5

ABSTRACT Previous studies reported that combined effect of magnetic field (MF) on cytotoxic drugs in human cancer cells. We focused on the effects of 60 Hz MF on drug activity in human uterine sarcoma MES-SA and drug-resistant variant MES-SA/Dx5 cells that overexpressed the membrane protein MDR1(P-glycoprotein), a drug efflux transporter for doxorubicin, daunorubicin, and etoposide, but not cisplatin. The cisplatin with MF caused 60% decrease in cell viability when compared with no MF treatment, cisplatin alone in MES-SA cells. Even in MES-SA/Dx5 cells, MF exposure equally enhanced cisplatin activity. Then, MF enhanced doxorubicin and daunorubicin activity in MES-SA cells and caused 60% decrease in the cell viability compared with these drugs only but had less effect on these drugs in MES-SA/Dx5 cells. Etoposide activity was unaffected by MF exposure in both cell lines, although etoposide is a MDR1 substrate as with doxorubicin and daunorubicin. Thus, MF had no direct impact on MDR1 in the cell membrane. However, the differences in doxorubicin and daunorubicin activity between MES-SA and MES-SA/Dx5 data revealed that the presence of MDR1 in abundance prevented the enhancing effects of MF on doxorubicin and daunorubicin activity. These results suggested that MF may act in the opposite direction of MDR1, affect the drug influx transporters for doxorubicin and daunorubicin, and facilitate anticancer drug uptake into the cells.

MAGNETIC EFFECTS OF FERROFLUID FLOW IN A HEATED MICROCHANNEL WITH PERMEABLE WALLS

In this paper, we analyze the combined effects of magnetic field, nanoparticles volume fractions, variable viscosity of unsteady ferrofluid flow in a microchannel with parallel permeable walls oriented horizontally whose temperatures are held asymmetrically. Using similarity transformation process, the governing Navier-Stoke’s, energy equations and the associated initial boundary conditions (IBCs) are reduced to a set of dimensionless nonlinear partial differential equations with IBCs. The numerical method used for solving these equations is semi-discretization via centered finite difference with Runge-Kutta Fehlberg integration techniques. The effects of pertinent parameters on dimensionless fluid velocity, temperature, skin friction, Nusselt number are analyzed through graphical depiction using MAPLE software.

Physical factors in the medical rehabilitation of patients with chronic cerebral ischemia in the outpatient stage

To develop a new technology for medical rehabilitation of the patients with chronic cerebral ischemia on an outpatient basis using therapeutic physical factors (such as ozone therapy and magnetic field in combination with endomassage) against the background of rational pharmacotherapy and psychocorrection. There have been observed 122 patients with chronic cerebral ischemia stage I. They were divided into three groups by simple randomization. The patients of the group of comparison 1 (GC1) (n=39) had neurotropic pharmacotherapy (Cerepro and Mexidol) and a group psychotherapy; the rehabilitation programme of the patients of the group of comparison 2 (GC2) (n=41) included ozone therapy (intravenous infusions of ozone-oxygen mixture) in addition to the treatment program of GC1; the patients of the main group (MG) (n=42) received a combination of magnetic field exposure and endomassage in addition to the treatment program of GC2. Clinical monitoring, coagulation hemostasis, and cerebral vascular ultrasound were used to assess the treatment efficiency. The rehabilitation treatment performed on an outpatient basis with the inclusion of ozone therapy and the combined effect of magnetic field and endomassage in MG ensured the leveling of clinical symptoms in 91.2% of cases (p<0.01). The efficiency of rehabilitation in GC1 was 74.4%, with the additional use of ozone therapy in GC2 - 82.6%. The use of the new technology with the use of intravenous infusions of ozone-oxygen mixture and magnetic field in combination with endomassage against the background of rational pharmacotherapy and psychocorrection in medical rehabilitation of the patients with chronic cerebral ischemia on an outpatient basis provides a reliably significant increase in the effectiveness of rehabilitation measures.

Magnetoelectric coupling lights up spintronics path: Lithium battery ideas to tune magnetism

Magnetoelectric coupling lights up spintronics path: Lithium battery ideas to tune magnetism

Effect of magnetic field on stress corrosion cracking induced by Sulfate-reducing bacteria

Buried pipes are often affected by microorganisms and magnetic fields. In this paper, the stress corrosion cracking (SCC) behavior of X80 steel under the combined effect of magnetic field (MF) and sulfate-reducing bacteria (SRB) was studied by electrochemical and slow strain rate tensile testing. The synergistic effect of MF and SRB on SCC was expounded for the first time. Results confirmed that the sensitivity of SCC increased under 0~20 mT, which was attributable to the fact that the MF promoted the entry of diamagnetic corrosion anions into the corrosion pit and accelerated the paramagnetic Fe2+ to detach from the steel surface. MF and SRB not only independently improved the stress corrosion sensitivity of steel, but also had a synergistic effect. MF changed the arrangement of the biofilm. At 30 mT, the sensitivity of SCC decreased, which was due to the excessive MF inhibited the growth of SRB.

Effects of Variable Transport Properties on Heat and Mass Transfer in MHD Bioconvective Nanofluid Rheology with Gyrotactic Microorganisms: Numerical Approach

Rheology of MHD bioconvective nanofluid containing motile microorganisms is inspected numerically in order to analyze heat and mass transfer characteristics. Bioconvection is implemented by combined effects of magnetic field and buoyancy force. Gyrotactic microorganisms enhance the heat and transfer as well as perk up the nanomaterials’ stability. Variable transport properties along with assisting and opposing flow situations are taken into account. The significant influences of thermophoresis and Brownian motion have also been taken by employing Buongiorno’s model of nanofluid. Lie group analysis approach is utilized in order to compute the absolute invariants for the system of differential equations, which are solved numerically using Adams-Bashforth technique. Validity of results is confirmed by performing error analysis. Graphical and numerical illustrations are prepared in order to get the physical insight of the considered analysis. It is observed that for controlling parameters corresponding to variable transport properties c2, c4, c6, and c8, the velocity, temperature, concentration, and bioconvection density distributions accelerates, respectively. While heat and mass transfer rates increases for convection parameter and bioconvection Rayleigh number, respectively.

Magnetic field potential effects on the doxorubicin therapeutic activity in Ehrlich tumor growth.

AimTherapeutic choices for cancer patients include many combinations of therapeutic protocols. The present study aimed to investigate and discuss the combined effects of magnetic field and chemotherapy treatment on Ehrlich tumor-induced growth in Swiss albino mice. The benefits of both treatments are discussed and interpreted.MethodsFifty adult male mice were randomly divided into two groups; ten mice in the first group served as control group and forty in the second group which received a single dose IP injection of tumor fluid (0.02 Ml) to induce tumor. Ten days post injection to allow the tumor to growth, the 40 mice were sub- divided in to 4 sub-groups 10 mice pre each to introduce the treatment.ResultsThe results indicated tumor growth inhibition regarding mean tumor volume variation (ml) presented. All treatments display tumor growth prevention effect compared to control untreated mice. Treatment with Dox + 7G (MF) exposure exhibited a significant inhibition of tumor growth than that treated alone with DOX or magnetic field; 82% inhibition for DOX + MF 7 G against 60% for 7 G , and 31% for DOX only. Optical density data show a higher values of the molar absorption coefficient for all treated groups than untreated one. The fluorescence emission spectra of Hb show an emission peaks λem at 465, 515, and 639 nm. Hematological examination might indicate to discriminative effects to RBCs, WBCs or/and Hb for all treated groups. Moreover, treatment with Dox + 7G MF shows a proper discriminative effects than that treatment with DOX or magnetic field only. Osmotic fragility (OF) test indicates that the combination between drug and magnetic field have nontoxic effect against RBCs membrane.ConclusionOur findings support further exploration of the potential of magnetic fields in cancer therapeutics, either as adjunct or primary therapy. It may be due to enhancing the drug interaction with tumor cells which increase the therapeutic index of DOX and resulted in increased anti-tumor activity against Ehrlich tumor models. These benefits promote the use of the magnetic field in cancer with chemotherapy over the other traditional treatment agents this highly adapted manner can be used in improving the clinical treatment protocol and fights against cancer.

Influence of heat transfer on MHD Carreau fluid flow due to motile cilia in a channel

Mucus transport mediated by motile cilia in the airway is an important defense mechanism for prevention of respiratory infections. Cilia motility can be affected by temperature difference and magnetic field. In this research, we investigate the combined effects of magnetic field and buoyancy force due to temperature difference. In the present study, mixed convective flow of a Carreau fluid model through a ciliated channel is modeled and analyzed by a symplectic metachoronal wave. The momentum and energy equations for the Carreau fluid are modeled and simplified by the stream function and small Reynold’s number approximation. The influence of magnetic parameter, Carreau fluid parameter, Brinkmann number and Weissenberg number on velocity, temperature and pressure gradient are presented via graphs. It is observed that Hartmann number helps to decelerate the flow, whereas Weissenberg number, Grashof number and Carreau fluid parameter are responsible for the accelerated flow. The heat transfer rate rises by increasing the values of Hartmann number, Weissenberg number, Carreau fluid parameter and Brinkmann number.

Coupled effects of magnetic field, number of walls, geometric imperfection, temperature change, and boundary conditions on nonlocal nonlinear vibration of carbon nanotubes resting on elastic foundations

The present study focusses on the investigations of the combined effects of magnetic field, temperature, nonlocal parameter, number of walls, initial geometric imperfection and end supports on the nonlinear transverse vibrations of carbon nanotubes resting on linear and nonlinear elastic foundations. With the aids of Erigen's nonlocal elasticity, Euler-Bernoulli beam theories and van der Waal forces equation, systems of nonlinear partial differential equations governing the dynamics responses of slightly curved multi-walled carbon nanotubes resting on Winkler and Pasternak foundations in a thermal-magnetic environment are developed. The developed equations are decomposed into spatial and temporal equations using Galerkin separation approach. The time-dependent nonlinear differential equations are solved by homotopy perturbation method. Detailed studies are conducted to investigate the effects of the models parameters on the nonlinear vibrations of the structures. The parametric studies reveal that the frequency ratio decreases as the number of magnetic field strength, number of nanotube walls, temperature, spring constants and the ratio of the radius of curvature to the length of the slightly curved nanotubes increase. It is established that these trends are the same for all the boundary conditions considered. The study also reveals that the clamped-simple supported multi-walled nanotubes have the highest frequency ratio while the clamped-clamped supported multi-walled nanotubes have the lowest frequency ratio. Further investigations show that quadruple-walled carbon nanotubes can be taken as pure linear vibration even at any value of linear Winkler and Pasternak foundations constants. Such result can be used to control the nonlinear vibration of the carbon nanotubes and also restrains the chaos vibration in the objective structure. The findings in this work will help in the design of multi-walled carbon nanotubes for various structural, electrical, mechanical and biological applications in a thermal and magnetic environment.

MHD natural convection in inclined wavy annulus utilizing hybrid nanofluid with discrete wavy coolers

In the present framework, the combined effect of magnetic field (Hartmann number, Ha), angle of inclination $$(\alpha )$$ , nanoparticle volume fraction $$(\chi )$$ , number of oscillations (N) and aspect ratio (AR) is investigated for natural convective heat transfer analysis containing hybrid nanofluid suspension ( $$\hbox {Al}_2\hbox {O}_3$$ and Cu) in wavy annulus having circular heater in the center and discrete coolers on the wavy walls. The homogeneous hybrid nanoliquid (0.1% of $$\hbox {Al}_2\hbox {O}_3{-}\hbox {Cu}/\hbox {water}$$ ) model with fitted correlations of viscosity and thermal conductivity from the experimental data is used, and results are evaluated for different ranges of controlling parameters: Rayleigh numbers ( $$\hbox {Ra}=10^3$$ – $$10^6$$ ), Hartmann number (Ha $$=$$ 0–50), aspect ratio (AR (D/H) = 0.2–0.6), number of oscillations or undulation parameter ( $$N=2$$ –8) with fixed amplitude ( $$a\,=\,0.02$$ ), angle of inclination ( $$\alpha =0{^{\circ }}$$ – $$135{^{\circ }}$$ ) and nanoparticle volume fraction ( $$\chi =0$$ –0.02) using Galerkin finite element method (GFEM) with triangular mesh. The mesh grid independency test has been conducted with different meshes (degree of freedoms), and a refined mesh with domain elements $$=$$ 21,662, boundary elements $$=$$ 884 and degree of freedoms (DOFs) $$=$$ 179,703 has been selected for entire computations. The average Nusselt number is evaluated as a function of Ra, $$\alpha$$ and N for different parametric ranges of $$\chi$$ , Ha and AR, respectively. The average heat transfer follows as zigzag pattern with increment in waviness (undulation parameter), and it has a minimum value for inclination angle $$=\pi /2$$ . With high Rayleigh number ( $$\hbox {Ra}>10^5$$ ), the average Nusselt number shows opposite trend with hybrid nanoparticle concentration. This type of research can be used in the design of an appropriate nanofluid-based cooling system for electronic components to ensure effective operational conditions.

Combined effect of magnetic field and hydrostatic pressure on the phase transitions exhibited by Ni-Mn-In metamagnetic shape memory alloy

We present a systematic study of the magnetostructural and magnetic transitions in the prototype metamagnetic shape memory alloy Ni50Mn34.5In15.5 under hydrostatic pressure and combined pressure and magnetic field. Pressure extends the area of stability of the antiferromagnetic martensitic phase. At low magnetic field the pressure derivatives of the Curie temperatures of austenite, TCA, and martensite, TCM, show opposite signs. This fact is described in the framework of the Landau thermodynamic model as arising from a weak long-range antiferromagnetic state of martensite. Two volume magnetoelastic constants were estimated using the experimental values of the pressure derivatives of TCA and TCM. A correlation between the signs of the pressure shifts of TCA, and TCM and the distance between Mn-Mn nearest neighbours is established, which matches the empirical Castelliz-Kanomata diagram. The entropy change at martensitic transformation (MT), ΔSMT, grows up when the MT temperature, TM, is approaching TCA under the influence of pressure, but under constant non-zero pressure this dependence is inverse.