Effect Of Magnetic Field Research Articles

Magnetic field platform for experiments on well-mixed and spatially structured microbial populations

Magnetic fields have been shown to affect sensing, migration, and navigation in living organisms. However, the effects of magnetic fields on microorganisms largely remain to be elucidated. We develop an open-source, 3D-printed magnetic field exposure device to perform experiments on well-mixed and spatially structured microbial populations. This device is designed in AutoCAD, modeled in COMSOL, and validated using a Gaussmeter and experiments on the budding yeast Saccharomyces cerevisiae. We find that static magnetic field exposure slows the spatially structured expansion of yeast mats that expand in two dimensions, but not yeast mats that expand in three dimensions, across the surface of semi-solid yeast extract-peptone-dextrose agar media. We also find that magnetic fields do not affect the growth of planktonic yeast cells in well-mixed liquid yeast extract-peptone-dextrose media. This study provides an adaptable device for performing controlled magnetic field experiments on microbes and advances our understanding of the effects of magnetic fields on fungi.

The direct role of nuclear motion in spin-orbit coupling in strongly correlated spin systems.

The interaction between the magnetic moment of an electron and the magnetic field generated by a moving charge is one component of the spin-orbit interaction. The nuclei in a molecule or solid are charged, are generally in vibrational motion, and so contribute to this interaction, but the direct coupling between nuclear momentum and electron spin is normally ignored in discussions of spin-forbidden phenomena such as transitions between states of different spin, even when the nuclei are recognized as playing a fundamental role (spin-vibronic coupling). Here, we investigate the spin-orbit interaction in a Heisenberg model interacting with vibrating point charges representing nearby bridging ligands. To reach the model, we apply second order perturbation theory to the Hubbard model with the spin-orbit interaction. In contrast to the other components of the spin-orbit interaction, the part that directly couples the momentum of the charge and electron spin appears at first order as an effective magnetic field at each site. We find that the inclusion of this nuclear-motion induced spin-orbit coupling can increase the rate of otherwise spin-forbidden transitions between different spin states of the Heisenberg model by many orders of magnitude. This overlooked interaction may, therefore, play a significant role in spin-forbidden phenomena such as spin relaxation in coupled spin-qubits.

Analyzing the Effect of Magnetic Field Strength on the Behavior of Ferromagnetic Materials in United States

Purpose: The aim of the study was to analyzing the effect of magnetic field strength on the behavior of ferromagnetic materials in United States. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: In the United States show that magnetic field strength affects the behavior of ferromagnetic materials by inducing structural changes, influencing lattice distortions and phase transformations. These findings deepen our understanding of magneto structural coupling, aiding material design. Additionally, research on magnetostriction behavior highlights the interplay between field strength, microstructure, and response. Unique Contribution to Theory, Practice and Policy: Domain theory, stoner-wohlfarth model & micro magnetic theory may be used to anchor future studies on magnetic field strength on the behavior of ferromagnetic materials. Conduct systematic experimental studies to validate theoretical predictions and elucidate the practical implications of magnetic field effects on material behavior. Governments and funding agencies should allocate resources to support research infrastructure for studying magnetic materials and phenomena.

Revealing the characteristics of oxygen evolution reaction performance of NiZn ferrites

Magnetic field-assisted method has been proved as an effective method to improve oxygen evolution reaction performance (OER) of water splitting, however, the essential reason for the improvement of OER performance still remains unclear. Herein, Ni1-xZnxFe2O4 ferrites were prepared by the combination of hydrothermal and calcination method, the magnetic properties, oxygen evolution reaction performance and the effect of applied magnetic field on OER performance were studied and discussed according to the magnetic properties and ion site situation. The magnetic field effect depended on the applied magnetic field strength and the magnetic magnetization density of catalysts, it was attributed to changes of electron state and redistribution of ions in the spinel structure. The overpotential decreased by approximately 50 mV and its double layer capacitance increased about 60 % at 125 mT applied magnetic field. The results provided a newness research view for the domain of electrochemistry.

Altitude Heterogeneity of Magnetic Fields and Doppler Velocities in the Area of Seismic Source of a Strong Solar Flare from Data in Helium, Sodium, and Nickel Lines

Measurements of magnetic fields near seismic sources during solar flares are vital for understanding the dynamics of solar activity. We used spectropolarimetric observations of the X17.2/4B solar flare on 28 October 2003, over a wavelength interval of 43 Å, including the D3, D2, D1, and Ni I 5892.88 Å lines, to analyze the Stokes I ± V profiles. Effective magnetic fields within 0.5–1.5 kG were measured in the D1, D2, and D3 lines at different flare locations, with the photospheric Ni I 5892.88 Å line showing a weaker field of below 0.5 kG. The D3 line showed rapid plasma descents of up to 11 km/s, in contrast to the slower velocities within 2.3 km/s observed in other lines. The differing amplitudes in the I + V and I − V profiles indicated potential non-Zeeman polarization effects. Secondary Stokes V peaks were also detected up to 8 Å from the D3 emission core. Significant altitudinal inhomogeneity in the magnetic field strengths was detected, possibly indicating the local magnetic collapse, facilitating the Lorentz-force driven mechanism of the seismic source excitation.

Finite deformation modeling of wrinkling in thin magnetoelastic sheets

This paper presents an asymptotic two-dimensional (2D) finite-deformation theory for a thin magnetoelastic sheet starting from a three-dimensional (3D) variational form. This theory is used to model wrinkling phenomena under applied traction and external magnetic field. The resulting 2D potential energy is specialized to an isotropic, in compressible material, and the expressions for material constants, i.e., elasticity tensor, magnetoelastic coupling constant, and permeability, are obtained as a function of the applied magnetic field. The formulation is further simplified assuming reflection symmetry about the mid-surface of the sheet. Strong form of the resulting 2D governing equations are obtained by setting the first variation of potential energy functional to zero. The resulting governing equations are used to analyze wrinkling in a stretched rectangular sheet placed in a uniform magnetic field. Approximate analytical solutions are obtained by linearizing the 2D plate equation for small slopes. The effect of magnetic field and applied stretch on onset of wrinkling and amplitude of wrinkles is studied.

Exploring the effect of axial magnetic fields on the thermal stability of SWBNNTs resting on elastic medium using the N-TBT

Exploring the effect of axial magnetic fields on the thermal stability of SWBNNTs resting on elastic medium using the N-TBT

Effect of magnetic field on macroscopic hysteresis and microscopic magnetic domains for different ferromagnetic materials

The macroscopic hysteresis of ferromagnetic materials is influenced by their microscopic magnetic domains, establishing a correspondence between the two that enables a fundamental understanding of the magnetization process of ferromagnetic materials. Based on this, this study employs the phase field method to investigate the macroscopic hysteresis and microscopic magnetic domain evolution of soft, hard, and rectangular ferromagnetic materials. The hysteresis loops of the three materials present narrow, wide and rectangular characteristics respectively, which are quantitatively consistent with the experimental data. Subsequently, the influence of the magnetic field on the macroscopic hysteresis is analyzed. The results show that the hysteresis loop area increases when the magnetic field amplitude increases. Furthermore, the proportion of each type of energy under different magnetic fields is discussed, the dominant energy terms are generally consistent for the same category of ferromagnetic materials. Additionally, the corresponding magnetic domain evolution under different magnetic field is displayed, with soft magnetic materials exhibiting no vortex structures, hard ferromagnetic materials presenting a 45° vortex structure, and rectangular magnetic material showcasing a 90° vortex structure. Finally, the asymmetric characteristics of the major hysteresis loop and minor hysteresis loops are discussed. The change of the magnetic field path leads to the corresponding change of the major and minor hysteresis loops. At the same magnetic field, distinctions in magnetic domain configurations between the major and minor hysteresis loops are evident.

Effect of rainbow gravity, PDM, and external magnetic field on optical properties and energy spectra of GaAs quantum dot

Effect of rainbow gravity, PDM, and external magnetic field on optical properties and energy spectra of GaAs quantum dot

High magnetic field effects on the phase separation behaviour of Fe-15mass%Cu alloys probed by 57Fe Mössbauer spectroscopy

High magnetic field effects on the phase separation behaviour of Fe-15mass%Cu alloys probed by 57Fe Mössbauer spectroscopy

Effects of magnetic field on removal of light non aqueous phase liquid from unsaturated zone using steam injection

Effects of magnetic field on removal of light non aqueous phase liquid from unsaturated zone using steam injection

The Xe isotope nuclear resonance frequency shift of NMR angular velocity sensors due to transverse gradient magnetic fields

The nuclear magnetic resonance (NMR) angular velocity sensor detects angular velocity by measuring the shift in the nuclear spin precession frequency, which is of fundamental interest. Recent studies have revealed the parameter dependency of nuclei frequency shifts induced by non-uniformly distributed polarized pump beams, temperature, and magnetic field properties. In this study, we investigated the effect of the linear transverse gradient magnetic field on the frequency ratio shift of the Xe isotope nuclear resonance frequency in the NMR sensors. A theoretical analysis method was proposed based on the Fermi contact interaction in atomic polarization and the spin-diffusion relaxation of 129Xe and 131Xe nuclei. The frequency ratio shift of the Xe isotope under different x-axis gradient magnetic fields was measured experimentally. Furthermore, we eliminated the equivalent residual magnetic field through a feedback system and compensated for the original gradient magnetic field in the system, which contributed to accurately revealing the frequency shift induced by the magnetic field gradient. The results indicate that the frequency ratio shift of the Xe isotope is proportional to the strength of the second-order linear transverse gradient magnetic field. This study provides a reference for the analysis and evaluation of the presence of the gradient magnetic field in the NMR angular velocity sensor.

Analyzing the Effect of Magnetic Field on the Performance of Heat Exchanger

Analyzing the Effect of Magnetic Field on the Performance of Heat Exchanger

Effect of Constant Longitudinal Magnetic Field on Microstructure and Tensile Behavior of Welded Joint of AZ91D Alloy

Effect of Constant Longitudinal Magnetic Field on Microstructure and Tensile Behavior of Welded Joint of AZ91D Alloy

Tuning the Multilevel Hierarchical Microarchitecture of MXene/rGO‐Based Aerogels Through a Magnetic Field‐Guided Strategy Toward Stepwise Enhanced Electromagnetic Wave Dissipation

AbstractHierarchical microarchitecture engineering is a state‐of‐the‐art approach to designing aerogel electromagnetic (EM) wave absorbers, offering huge potential in improving EM energy dissipation. However, the intrinsic feedback mechanism regarding the specific influence of each microarchitecture parameter on EM properties is not comprehensively revealed, making it challenging to fully utilize the potential of aerogels to achieve superior EM wave absorption performance. Herein, a range of MXene/rGO‐based aerogels with multilevel hierarchical configurations are fabricated by a magnetic field‐guided strategy. Leveraging growth thermodynamics effects under a magnetic field and bridging effect between adjacent rGO units, three hierarchical microarchitecture models (lamellae ordering, interlayer spacing, and layer thickness) are constructed in aerogels. Remarkably, three models progressively improve reflection loss (RL), effective absorption bandwidth (EAB), and matching thickness by enhancing dielectric loss, decoupling attenuation‐impedance matching, and adjusting power loss density, respectively. Consequently, the MXene/rGO‐based aerogels exhibit stepwise enhancement in EM wave performance, achieving a superior RL of −64.6 dB and a broad EAB of 7.0 GHz at 1.8 mm thickness, surpassing alternative aerogels with other configurations. This work elucidates the effect of multilevel hierarchical microarchitecture on the synergistic multi‐effect dissipation mechanism of EM waves in aerogels, providing insights for designing advanced EM absorbers through diverse strategies.

Control of Three-Dimensional Natural Convection of Graphene–Water Nanofluids Using Symmetrical Tree-Shaped Obstacle and External Magnetic Field

This numerical investigation explores the enhanced control of the 3D natural convection (NC) within a cubic cavity filled with graphene–water nanofluids, utilizing a bottom-center-located tree-shaped obstacle and a horizontal magnetic field (MF). The analysis includes the effects of the Rayleigh number (Ra), the solid volume fraction of graphene (φ), the Hartmann number (Ha), and the fins’ length (W). The results show complex flow patterns and thermal behavior within the cavity, indicating the interactive effects of nanofluid properties, the tree-shaped obstacle, and magnetic field effects. The MHD effects reduce the convection, while the addition of graphene improves the thermal conductivity of the fluid, which enhances the heat transfer observed with increasing Rayleigh numbers. The increase in the fins’ length on the heat transfer efficiency is found to be slightly negative, which is attributed to the complex interplay between the enhanced heat transfer surface area and fluid flow disruption. This study presents an original combination of non-destructive methods (magnetic field) and a destructive method (tree-shaped obstacle) for the control of the fluid flow and heat transfer characteristics in a 3D cavity filled with graphene–water nanofluids. In addition, it provides valuable information for optimizing heat transfer control strategies, with applications in electronic cooling, renewable energy systems, and advanced thermal management solutions. The application of a magnetic field was found to reduce the maximum velocity and total entropy generation by about 82% and 76%, respectively. The addition of graphene nanoparticles was found to reduce the maximum velocity by about 5.5% without the magnetic field and to increase it by 1.12% for Ha = 100. Varying the obstacles’ length from W = 0.2 to W = 0.8 led to a reduction in velocity by about 23.6%.

A review on the magnetorheological materials and applications

Magnetorheological materials refer to field-response smart materials whose properties are controllable with a magnetic field, including fluid, grease, elastomer, and gel. The unique magnetorheological effect exhibited by these smart materials is a physical phenomenon where physics and engineering intersect and has extensive application prospects in modern machinery. In electro-mechanical systems, magnetorheological materials offer a superior design method for mechanical devices used in the fields of transmission, damping, and braking. It is important to control the magnetorheological materials for advancing the design philosophy of modern electro-mechanical devices. Hence, this paper presents a recent progressive review on the fundamentals of magnetorheological materials and numerous applications. Firstly, an introduction to the magnetorheological effect and different types of magnetorheological materials are presented in this review. Then, the individual and coupled effects of sedimentation, temperature, and magnetic field on magnetorheological materials are discussed. Finally, magnetorheological materials-based devices have been extensively reviewed, including actuator, clutch, damper, brake, pump, valve, and robot, thus aiming to provide useful information for facilitating the design of complex electro-mechanical systems.

Effect of bias magnetic field on transducer efficiency in electromagnetic ultrasonic non-destructive testing of Rock bolt

Non-destructive testing (NDT) of rock bolt anchoring quality is an important part of engineering quality and safety control, electromagnetic ultrasonic NDT is one of the promising detection methods, and improving the efficiency of ultrasonic transducer by optimizing the bias magnetic field is an important factor to obtain effective information. In this paper, several factors affecting the bias magnetic field are studied, and the work is divided into simulation and demonstration: COMSOL was used to simulate the electromagnetic ultrasonic transducer(EMAT) in order to analyze the influence of the number of magnetic circuit, the thickness of magnet and the thickness of yoke iron on the bias magnetic field. Then, an experimental platform was built, the magnetic circuit structure of the transducer was set with reference to the simulation results, and several important parameters of the bias magnetic field were determined by analyzing the collected signals. The results show that with the increase of the bias magnetic field magnetic circuit structure from independent to ring form, the magnetic field strength of the rock bolt increases, the magnetic field uniformity becomes better, and the efficiency of the transducer is also improved accordingly. In addition, under the same magnetic circuit condition, increasing the thickness of permanent magnet and yoke iron does not increase the magnetic flux density of the rock bolt axis proportionally, and has a limited effect on the efficiency of the transducer. In practical application, the corresponding structure is selected according to the needs, and the better bias magnetic field structure is selected while meeting the efficiency of the transducer.

Effects of magnetic fields on the formation of passive films on the surface of 5083 aluminum alloy

This research explores the effect of the magnetic fields on the passive film of 5083 aluminum alloy. After the application of a 0.3 T magnetic field, 5083 aluminum alloy exhibits an improvement in passivation performance. These improvements manifest as a reduction in passivation current density and an increase in impedance, passive film thickness, and carrier concentration. Additionally, there is an augmentation in the content of the Al2O3 phase within the passive film. The magnetic field facilitates the movement of metal ions during the corrosion process of 5083 aluminum alloy through microscale magnetohydrodynamics, facilitating passive film growth and improving corrosion resistance.

Magnetic field effect on the electric permittivity of rare-earth aluminium borates

The renormalization of the electric permittivity of rare-earth aluminium borates is studied theoretically from the first principles. It is shown how the electric permittivity depends on the external magnetic field and temperature for several compounds of rare-earth ions of that class.