Optimization of magnetic field parameters in a system with symmetrical c-shaped poles using conformal mapping

We have to admit that the literature concerning bioeffects of electromagnetic fields is replete with reports that cannot be reproduced in other labs. Besides the intended or sub-conscious experimenter bias, which can be avoided or much reduced by the gold standard of blinded analysis, most inconsistences in the literature were actually caused by confounding effects, different magnetic field parameters, and biological sample differences. The goal of this chapter is to summarize the factors that contribute to the differential bioeffects of static magnetic fields (SMFs), including magnetic field exposure parameters, such as magnetic field types, magnetic flux density, homogeneousness, field direction and distribution, exposure time, as well as biological sample differences, including cell type, cell density, cell status, and other factors. It is clear that all these aspects are crucial for the diverse effects of SMFs on biological samples, which also lead to the seemingly lack of consistencies in literature. Therefore, we encourage people to not only perform double blinded analysis in independent studies, but also clearly describe the experimental details, including various magnetic field exposure parameters, biological samples, and experimental procedures. This will be crucial for people to perform further subjective analysis and mechanistic investigations.KeywordsMagnetic field (MF)Static magnetic fields (SMFs)Time-varying magnetic field (TVMF)Dynamic magnetic field (DMF)Magnetic field intensityGradient magnetic fields (GMF)Differential effects of magnetic fields

This research investigates Casson fluid flow over a vertical porous (absorbent) surface under a suitable applied magnetic field in the presence of a chemical reaction. The effects of various physical parameters, including the volume fraction of penetrable spheres, suction rate, Schmidt and Casson fluid numbers, magnetic field strength, and chemical concentration on the fluid mass transfer and momentum characteristics, specifically the Sherwood number and skin friction, are studied. The flow and mass-transfer equations governing the two phenomena are transformed into a nonlinear system of ordinary differential equations via similarity transformations. The velocity and concentration profiles under different parameter values are obtained by numerically solving the BVP using BVP4C in MATLAB. The quantitative results demonstrate that, while an increase in the Grashof number decreases skin friction, increases in the volume fraction, suction parameter, Schmidt number, Casson parameter, magnetic parameter, and chemical concentration increase skin friction. Conversely, the g (acceleration due to gravity) decreases with increasing Casson and magnetic field parameters, but increases with the chemical concentration, Grashof, Schmidt, suction, and volume fraction. These findings are corroborated by published literature. The current study has applications in the development of magnetic nanoparticles for targeted drug delivery, enhanced heat and mass transport phenomena in porous media processing, and the production of microfluidic devices, where control over chemically reactive, magneto-sensitive, non-Newtonian fluids is crucial.

The present article addresses the steady and laminar magnetohydrodynamics (MHD) flow of a micropolar nanofluid between two porous disks. The fluid is flowing uniformly in the inward and upward directions from both disks. The microrotation of the nanoparticles acts an important role in the flow regime. To show its significance, a comparative study of the analytical results and numerical results is presented. Titanium dioxide is chosen as nanoparticles in the water-based fluid. An appropriate transformation is used for transforming PDEs into ODEs. These nonlinear ODEs are computed by the differential transform method (DTM). The consequences of the Reynolds number, material parameter, and magnetic parameter on the radial velocity, axial velocity, and microrotation profile are graphically presented and discussed. The results calculated by DTM and the results calculated numerically are compared and tabulated. This comparison shows the accuracy and validity of DTM. The coefficient of skin friction is also tabulated and compared with the numerical result. At the end of this study, it is concluded that the behavior of the radial and the axial velocities and the microrotation profile are almost the same in the case of the Reynolds number and the magnetic field parameters.

The article discusses a field geophysical complex that includes the Earth's gravity and magnetic fields parameters meters — an digital zenith camera (DZC), a relative gravimeter, onboard quantum magnetometer and ground magnetovariation station. This complex allows determining such parameters of the Earth's gravity field as acceleration and anomalies of gravity, plumb line deviations, horizontal components of the acceleration of gravity and gravitational gradients, and parameters of the Earth's magnetic field — absolute and anomalous values of induction. Maps of the Earth's gravity and magnetic fields can be used in various fields, in particular, in the creation and testing of integrated autonomous navigation systems using the parameters of these fields. The paper presents examples of parameter maps created using this complex. The measurement error of acceleration and gravity anomaly is 10 µGal, plumb line deviation is ≈ 0.2″, horizontal components of gravity acceleration are ≈ 1 mGal, gravitational gradients are 10 Eötvös at a distanc

The thermal processes with inclusion of nanomaterials provide a wide range of applications pertaining to heat exchangers and cooling of compact heat density devices. The current research investigates the three-dimension flow of hybrid nanofluid comprising TC4(Ti-6A-14V) and Nichrome 80% Ni and 20% Cr nanoparticles mixed within engine oil as the base fluid for the enhancement of heat and mass transfer rate. The effects of homogeneous-heterogeneous processes and thermal radiation are incorporated. The heat transfer occurs due to a rotating inclined stretched sheet is discussed against prominent factors such as thermal radiation, inclined angle parameter, rotation parameter, and heat source/sink. The leading mathematical formulation consists of a set of PDEs, which are then transmuted into ordinary differential equations using suitable similarity transformation. The numerical solutions are obtained by using MATLAB's built-in function bvp4c. The results for velocity profile, temperature profile and concentration distribution are evaluated for suitable ranges of the controlling parameters. The graphical result shows that when the angle of inclination, magnetic parameter, and the volumetric concentration of hybrid nanomaterials increase the axial flow profile of the hybrid nanofluid is reduced. However, the rotation parameter reveals the opposite response. The temperature is intensified with an increment of heat source/sink, shape factors, and magnetic field parameter. For enhanced nanoparticle volumetric concentration, the temperature of the fluid rises up. The graphical validation is also illustrated using streamlines and statistical plots for hybrid nanofluid.

The modern world is utilizing solar thermal radiation and nanotechnology to advance new technologies. Nanofluids have a significant influence on the performance of solar thermal systems by enhancing their ability to heat transfer. Solar energy, which is primarily derived from the sun, is applied in numerous technologies such as photovoltaic cells, solar-powered vehicles, solar panels, street lighting, solar thermal aircraft, and water-pumping systems. Keeping such applications in mind, researchers are exploring how nanotechnology can enhance solar thermal radiation to improve aircraft flight efficiency. Hence, this study aims to contribute effectively to the field of solar aviation by utilizing advanced nanotechnology. Given the drawbacks of traditional energy sources, solar power emerged as a solution to the need for reliable, cost-effective, and environmentally friendly renewable energy. Therefore, this research is carried out through the development of a mathematical model that mimics the flow and thermal properties of a parabolic trough surface collector (PTSC) attached to the wing of a solar aircraft. The main objective of this investigation is to analyze magnetized tetra-hybrid Williamson nanofluid (NF) flowing through an aircraft wing's internal PTSC concerning flow properties, temperature distribution, surface friction, entropy generation, and heat transfer. The governing equations are transformed into ordinary differential equations with suitable non-similarity transformations and then tackled numerically via the Bvp4c function in MATLAB. Furthermore, Artificial Neural Networks (ANNs), Response Surface Methodology (RSM), and stability analysis are employed to enhance the heat transfer and surface friction performance of the proposed tetra-hybrid Williamson NF flow. To achieve this, the magnetic number, radiation parameter, and porosity parameter are selected for conducting RSM, ANN, and stability analysis to improve heat transfer and surface friction. The results indicate that tetra-hybrid NFs (TTHNFs) exhibit superior thermal transfer compared to NFs, hybrid nanofluids (HNFs), and ternary nanofluids. As solar radiation and magnetic field parameters improve, the wing performance of airplanes is enhanced in heat transfer situations. Therefore, this study provides important information for improving solar-powered aircraft thermal management and cutting-edge nanotechnology. Additionally, the magnetic, solar radiation, and porosity parameters decrease entropy generation, while the porosity parameter reduces surface friction. Sensitivity analysis performed using RSM indicates that drag force is positively influenced by the porosity parameter, while heat transfer is positively influenced by the magnetic parameter. Finally, the statistical analysis of surface friction and thermal transport in the current model, along with the testing methods, shows high R2, predicted R2, and adjusted R2 values (99.99%, 99.99%, and 99.96%, and 99.99%, 99.99%, and 99.99%) for the response function, demonstrating that this model is well suited for predicting both drag force and heat transfer. The heat transfer performance was evaluated for NFs, HNFs, ternary hybrid (THNFs), and tetra-hybrid nanofluids under magnetic, radiation, and porosity parameters. Compared to the NFs, HNFs improved heat transfer by approximately 8%–9%, THNFs by 18%–20%, and TTHNFs by 41%–45% across all parameters. These enhancements show a clear trend of increasing thermal performance with the addition of more types of nanoparticles. Additionally, the reliability of the proposed ANN model is validated by assessing its precision, accuracy, and convergence using error histograms, performance plots, and fitness curves for heat transfer and surface friction.

For the reasearch of magnetic memory testing parameters on the effect of magnetic memory testing signals, the method of uniform design experiment is used to arrange test, by the decision criteria of the minimum component change of magnetic field, the mathematical model is established based on the test result, quantify the influence of the magnetic memory testing parameters, and optimal regression equations are verified through the test results, and achieve the optimization of test parameters, the results for the determination of magnetic memory testing parameters and the range of choice to provide theoretical reference, and improve the reproducibility of test results.

Nanofluids are potential liquids that enhance the thermophysical characteristics and the ability to transport heat rather than base liquids. This article discusses the non-isothermal heat transfer of the convective steady flow of magnetohydrodynamic micropolar nanofluid over a non-linear extended wall, considering the effects of Brownian motion and thermophoresis, coupled stress, hall current and viscous dissipation effects. Fluid flow is controlled by a high magnetic field. The system of equations is resolved using the Homotopy Analysis Method (HAM) technique and the results are visualized graphically. The effects of different fluid parameters summarizing the problem behavior on primary, secondary and angular velocity, temperature, volume fraction and nanoparticle concentration profiles are measured using graphs. The primary velocity component decreased throughout the entire flow study with magnetic, couple stress and Hall parameters. The large magnetic field parameter and the smaller couple stress parameter lower the secondary velocity, while the increase of the local Grashof number increases the secondary velocity. The strong magnetic parameter, the local Grashof number and the couple stress parameter reduce the angular velocity as observed. The large magnetic parameter, Grashof number, Hall parameter and radiation parameter reduces temperature, while the temperature increases with the increase in Brinkman number and Prandtl number. Brownian motion and thermophoresis encourage the transfer of heat. Tables are used to highlight the impact of dimensionless parameters on the skin friction coefficient, Nusselt and Sherwood numbers.

High-speed streams (HSSs) are believed to be only slightly affected by different interactions on their path from the Sun to Earth and thus the analysis of their observations can provide information on the structure and temporal variations of the magnetic field and plasma parameters at the source region. We have chosen three coronal holes supplying 14 HSSs recorded by Wind in 2008. For each HSS, we have calculated the average magnetic field and plasma parameters as well as power spectral densities (PSDs) of magnetic field fluctuations in the MHD and kinetic ranges to investigate their long- and short-term variations. We suggest that long-term variations are connected with a time evolution of the source region on the time scale of solar rotations. On the other hand, the short-term variations would reflect a longitudinal structure of the coronal hole. Our study reveals that coronal holes are very stable source of HSSs and their temporal evolution on short- and long-time scales is negligible. This is true for the average parameters as well as for the fluctuation power and PSDs. Observed correlations between bulk and/or thermal velocity and PSD parameters are consistent with already published results. We suggest that they do not originate in the source region but they can be mostly attributed to interaction with the ambient slow wind that affects even the HSS core.

In the present study, we have investigated the steady mixed convection nonaxisymmetric Homann stagnation-point flow in the presence of a magnetic field over a vertical flat wall immersed in a viscous and incompressible fluid. The magnetic field is applied in the normal direction to the plate. The governing equations are reduced to a system of nonlinear ordinary differential equations with suitable boundary conditions by applying similarity transformations to the equations and the boundary conditions. Using an efficient shooting method, the transformed equations are numerically solved. The solution involves the dimensionless governing parameters: γ representing the shear-to-strain-rate ratio, a mixed convection parameter λ, a magnetic field parameter M, and Prandtl number Pr. An important observation is that dual solutions exist for a certain range of mixed convection parameter λ. It is noticed that critical values λc of λ are found in opposing flow, which produce two solution branches by making saddle-node bifurcation at λ = λc. Numerical results are obtained for representative values of γ, λ, and M and are explored in depth. Through the use of graphs, the properties of the flow and temperature profiles for various values of the governing parameters γ, λ, and M are examined. Also, we examined how the solution varied with λ for representative values of M (magnetic field parameter). A parametric analysis is conducted to investigate how different governing parameters affect the characteristics of fluid flow and temperature. Also, we derive asymptotic results for large λ.

Abstract. Taking into account the pressure anisotropy in the solar wind, we study the magnetic field and plasma parameters downstream of a fast shock, as functions of upstream parameters and downstream pressure anisotropy. In our theoretical approach, we model two cases: a) the perpendicular shock and b) the oblique shock. We use two threshold conditions of plasma instabilities as additional equations to bound the range of pressure anisotropy. The criterion of the mirror instability is used for pressure anisotropy p \\perp /p\\parrallel > 1. Analogously, the criterion of the fire-hose instability is taken into account for pressure anisotropy p \\perp /p\\parrallel < 1. We found that the variations of the parallel pressure, the parallel temperature, and the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock. Finally, we compare our theory with plasma and magnetic field parameters measured by the WIND spacecraft.

Aviation aspects of engine oil conveying copper tiny particles embedded in a rotating disk with a binary chemical reaction

This study investigated the effects of magnetic field, thermal radiation and viscous dissipation on transient magneto hydrodynamic (MHD) flow of non-Newtonian incompressible fluid obeying Eyring-Powell model in a porous medium. The governing equations were formulated and transformed into non-dimensional equations. Numerical solution to the transformed governing nonlinear partial differential equations was obtained using the implicit finite difference scheme of Crank-Nicolson type. The finite difference equations form Thomas algorithm tri-diagonal matrix system of equations which was solved using the MATLAB. The results showed that a rise in Non-Newtonian parameter F, thermal Grashof number Gr, modified Grashof number Gm and dissipation function Ec, caused velocity to increase whereas velocity decreased with increase in Non-Newtonian parameter A, magnetic field parameter M, radiation parameter R, Schmidt number Sc, Prandtl Number Pr and chemical reaction parameter, g. Temperature increased with increase in dissipation function Ec, while it decreased as Prandtl number, magnetic field parameter and Radiation number increased. Increase in Schmidt number and chemical reaction result to a decrease in concentration. Keywords : Non-Newtonian; Radiation; Magnetic Field; Eyring-Powell Model; Dissipation.

This paper presents an experimental exploration of the electrophysical properties of high-temperature superconductors that is based on the determination of the constitutive equation parameters for the combined model with two sources of electromagnetic field: current density and magnetization. It involves a series of experiments in different external magnetic fields and various transition modes to the superconducting state that allows the individual field sources to be distinguished. Since conditions that would enable us to maintain a homogenous current density distributions and magnetization under varying external magnetic induction in the HTSs are not available, the magnetic field parameters and its sources in the samples are determined via computational and experimental methods, in which the magnetic field parameters in the sample are calculated using their values out of the sample. A special laboratory installation equipped with the required measuring tools and magnetic system to create a controlled external magnetic field with the magnetic flux density of 1.5 T is constructed for the practical implementation of the experimental research technique.

This paper concerns the second law analysis of a viscoelastic fluid over a stretching sheet subject to a transverse magnetic field with heat and mass transfer. The velocity, temperature and concentration profiles are obtained analytically using Kummer’s functions. The effects of the magnetic and viscoelastic parameters on both the longitudianl and the transverse velocities are investigated. The influence of Prandt number, the magnetic parameter and the heat source/sink parameter on the temperature is analysed. The concentration and its variations with the Schmidt number and the magnetic parameter is presented as well. The velocity, the temperature and the concentration profiles are used to compute the entropy generation number. This number is graphed and studied as function of the magnetic parameter, the Prandtl number, The Schmidt number, the Reynolds number, the dimensionless group, the Hartmann number, the ratio of the dimensionless concentration difference to the dimensionless temperature difference and the constant parameter.