Interaction Of Magnetic Field Research Articles

Magnetic dopant and field effects on the heat discharge of organic PCM based lauric acid

In this experimental study, we investigated the heat transfer characteristics during the freezing or heat discharging process of a magnetic-composite phase change material (PCM). Lauric acid (LA) was used as the PCM, Fe3O4and CoFe2O4 were utilised as dopants, and a permanent magnet generated the magnetic field.The time characteristic of freezing data revealed that the magnetic dopant and field increased the heat transfer rate. This improvement resulted in substantial time savings for the solidification process, with a 42% reduction observed for Fe3O4-composite LA and a 33% reduction for CoFe2O4-composite LA. Furthermore, the magnetic field contributed to the reduction in crystal size and crystal growth along the field direction, as observed by digital optical microscopy. The freezing data were correlated with thermal conductivity and viscosity, both strongly depending on the concentration and magnetic field. Their dependence on the magnetic characteristics of the dopant was also evident. The liquid thermal conductivity indicated a critical magnetic field that depends on the dopant type and concentration. For Fe3O4-composite LA and the CoFe2O4-composite LA, the highest liquid thermal conductivity ratios were 121% and 120%, respectively, and these values were achieved at the highest dopant concentration and magnetic field intensity. For small dopant concentrations, the viscosity generally decreased with increasing magnetic field intensity, while for high dopant concentrations, the trend was different. The heat transfer and magneto-viscosity characteristics were closely related to the collaborative effect of magnetic dipolar and magnetic field interactions. The magnetic dopant and field used to control PCM freezing are important factors for optimising the performance of a material as a latent thermal energy storage system.

Study on the effect of magnetic field on electrodeposition of NiCr alloy coating

Different NiCr coatings are prepared by magnetic field assisted electrodeposition on the surface of Q235B substrate. The influence of magnetic field intensity on thickness, surface roughness, hardness, surface morphology, composition, and corrosion resistance of NiCr coating is studied. The Lorentz force generated by the interaction of magnetic field and electric field will produce magnetohydrodynamic (MHD) phenomena near cathode surface to improve ions transfer rate and reduce the surface roughness, resulting in the increase of thickness and hardness. The electrodeposited NiCr coatings all show granular surface morphology. The metal cellular protrusions on the surface of NiCr coating prepared without magnetic field are nonuniform and agglomerated. The applied magnetic field is beneficial to refine the metal cellular protrusions and increase the chromium content in the NiCr coating, resulting in the enhancement of corrosion resistance. The NiCr coating obtained at the condition of 1T magnetic field has the largest thickness and the best corrosion resistance. However, when the magnetic field is increased to 1.5T, the chromium content in CoNi coating is reduced due to severe hydrogen evolution, resulting in the decrease of hardness and corrosion resistance.

Trends and prospects of 2-D tungsten disulphide (WS2) hybrid nanosystems for environmental and biomedical applications

Recently, 2D layered transition metal dichalcogenides (TMDCs) with their ultrathin sheet nanostructure and diversified electronic structure have drawn attention for various advanced applications to achieve high-performance parameters. Unique 2D TMDCs mainly comprise transition metal and chalcogen element where chalcogen element layers sandwich the transition metal element layer. In such a case, various properties can be enhanced and controlled depending on the targeted application. Among manipulative 2D TMDCs, tungsten disulphide (WS2) is one of the emerging nano-system due to its fascinating properties in terms of direct band gap, higher mobility, strong photoluminescence, good thermal stability, and strong magnetic field interaction. The advancement in characterization techniques, especially scattering techniques, can help in study of opto-electronic properties of 2D TMDCs along with determination of layer variations and investigation of defect. In this review, the fabrication and applications are well summarized to optimize an appropriate WS2-TMDCs assembly according to focused field of research. Here, the scientific investigations on 2D WS2 are studied in terms of its structure, role of scattering techniques to study its properties, and synthesis routes followed by its potential applications for environmental remediation (e.g., photocatalytic degradation of pollutants, gas sensing, and wastewater treatment) and biomedical domain (e.g., drug delivery, photothermal therapy, biomedical imaging, and biosensing). Further, a special emphasis is given to the significance of 2D WS2 as a substrate for surface-enhanced Raman scattering (SERS). The discussion is further extended to commercial and industrial aspects, keeping in view major research gaps in existing research studies.

Control of magnetic dissipation and radiation on an unsteady stagnation point nanofluid flow: A numerical approach

This study investigates two-dimensional time-dependent stagnation point nanofluid flow over a permeable stretching or sinking sheet. The electrically conducting fluid allows for the interaction of a transverse magnetic field along with magnetic dissipation and thermal radiation to enrich the flow phenomena. The use of nanofluids is becoming increasingly important in a variety of industrial applications, as well as in engineering and biomedicine. The process of peristaltic pumping, the flow of blood in the artery, the drug delivery process, and besides that, the cooling of electronic devices for the better shape of the product at the final stage of production, the use of nanofluid, are all important. The transformed dimensionless governing equations are obtained by the implementation of various transformation rules, and the model is designed by using different thermophysical properties such as viscosity, conductivity, etc. Finally, the numerical technique RK-fourth-order method is deployed to solve the set of equations and the iteration process is continued up to the desired accuracy of 10[Formula: see text]. The validation of the current result is shown with the earlier investigation in particular cases, and further, the behavior of the physical parameters is presented through graphs. It is observed that the particle concentration has a greater impact in enhancing the velocity distribution for the variation of suction/injection. The behavior of the magnetic parameter vis-à-vis the unsteadiness parameter and the thermal buoyancy presents their greater contribution in enhancing the magnitude of nanofluid velocity.

Managing Patients With Unlabeled Passive Implants on MR Systems Operating Below 1.5 T.

The standard of care for managing a patient with an implant is to identify the item and to assess the relative safety of scanning the patient. Because the 1.5 T MR system is the most prevalent scanner in the world and 3 T is the highest field strength in widespread use, implants typically have "MR Conditional" (i.e., an item with demonstrated safety in the MR environment within defined conditions) labeling at 1.5 and/or 3 T only. This presents challenges for a facility that has a scanner operating at a field strength below 1.5 T when encountering a patient with an implant, because scanning the patient is considered "off-label." In this case, the supervising physician is responsible for deciding whether to scan the patient based on the risks associated with the implant and the benefit of magnetic resonance imaging (MRI). For a passive implant, the MRI safety-related concerns are static magnetic field interactions (i.e., force and torque) and radiofrequency (RF) field-induced heating. The worldwide utilization of scanners operating below 1.5 T combined with the increasing incidence of patients with implants that need MRI creates circumstances that include patients potentially being subjected to unsafe imaging conditions or being denied access to MRI because physicians often lack the knowledge to perform an assessment of risk vs. benefit. Thus, physicians must have a complete understanding of the MRI-related safety issues that impact passive implants when managing patients with these products on scanners operating below 1.5 T. This monograph provides an overview of the various clinical MR systems operating below 1.5 T and discusses the MRI-related factors that influence safety for passive implants. Suggestions are provided for the management of patients with passive implants labeled MR Conditional at 1.5 and/or 3 T, referred to scanners operating below 1.5 T. The purpose of this information is to empower supervising physicians with the essential knowledge to perform MRI exams confidently and safely in patients with passive implants. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 3.

A double variable-length pendulum with counterweight mass, kinematic excitation and electromagnetic forcing

This study introduces a novel double variable-length cable pendulum model and experimental setup featuring elastic suspension and counterweight mass. Our main goal is to investigate the complex dynamics resulting from variable length’s impact on vibration frequency and amplitude. Through numerical simulations and experiments, we explore the system’s response to different external forces. Utilizing methods like phase plots, bifurcation diagrams, and Lyapunov exponents, we delve into nonlinear dynamics. We also use vision-based techniques to assess friction damping-related vibrations and magnetic field interactions. The results reveal diverse behaviors, including chaotic and periodic oscillations, shedding light on control functions and parameter relationships. The developed cable system captures intricate nonlinear dynamics and attains stable vibration modes, as confirmed by vision-based measurements. This platform can analyze and control irregular dynamics in systems with elastically suspended weights driven by motors or mobile cranes. Its nature, encompassing kinematic excitation, electromagnetic interactions, and sliding friction, allows for exploring complex nonlinear dynamics. The system’s capacity to modulate vibration frequencies contributes to mitigating persistent vibrations.

Conjugate dissipative radiative heating with thermal slipping and the entropy production on the thrust of MHD gold blood nanofluid with curvature effects

AbstractThis article analyzes the impact of conjugated dissipative radiative heat transfer with heat source/sink, thermal slip, and the transverse magnetic field on the behavior of the magnetohydrodynamic (MHD) peristaltic thrust containing ferromagnetic gold nanoparticles (AuNPs) with different shape factors through the non‐Newtionian blood flow within compliant walls tube. Entropy generation (EG) plays a prominent role in all aspects connected to thermodynamics and heat transfer aiding in the identification and reduction of system irreversibilities. The sources of irreversibility stem from dissipative friction inherent in fluid flow, the presence of a magnetic field, and the heat transfer process. The ferromagnetic gold nanoparticles (AuNPs) exhibit diverse shapes (bricks, cylinders, and platelets) and possess both magnetic and thermal attributes thereby enhancing the efficiency of heat transfer process. The peristaltic thrust drives the dynamic behavior of the gold blood nanofluid through a compliant tube. The tube walls are flexible and exhibit a curvature effects that can alter the dynamics of fluid flow. The effective Hamilton‐Crosser model is selected to express the thermal conductivity of the nanofluid. Gold blood nanofluids can be treated as incompressible, non‐Newtonian, and MHD fluid flow. The governing equations of the system are solved using the perturbation approach under the assumptions of low Reynolds numbers and long wavelength. Hybrid interactions of magnetic field, radiative heating, thermal slip, elastic wall properties, and gold nanoparticles shapes and concentrations are investigated within the gold blood nanofluid flow. The resulting graphs include the profiles of velocity, temperature distributions, EG, and irreversibility parameters under the influence of the above parameters. The findings reveal that the overall EG rises with increasing values of heat source intensity, Brinkman number, temperature difference factor, compliant wall curvature coefficient, and gold nanoparticles concentrations. Additionally, it is observed that an increase in magnetic flux strength results in the emergence of reversal flow patterns near the walls. This arises due to the augmented magnetic flux obstructing the peristaltic nanofluid flow leading to reduce streamwise velocity. Moreover, heightened magnetic flux strength causes temperature reduction for both thermal slip and non‐slip conditions. Generally, the presence of a thermal slipping parameter further enhances the distribution of temperature. In essence, the rationale and significance of this study primarily revolve around comprehending the interplay of these diverse factors with MHD peristaltic motion of gold blood nanofluid and EG. This not only furthers our theoretical understanding of complex systems but also has practical implications that can improve new technologies, processes, and medical applications. For example, in medical treatments like photothermal therapy (PPT), insights gained from this research can help in developing more effective and precise treatment methods. By understanding the impact of these factors on EG, new ways can be identified to minimize or manage system inefficiencies leading to more sustainable and optimized treatment processes. This research holds promise for application in cancer detection and treatment by employing a combination of PPT and magnetic hyperthermia. This entails dispersing AuNPs into the blood circulation through arteries and blood vessels and subsequently applying photothermal radiation and a magnetic field.

Heat and mass transfer by stirring nanofluids with the presence of renewable solar rays, Joule heating, and entropy procreation

Renewable solar radiation is the foremost energy source because of its accessibility, natural replication, and sustainability in an environmentally safe manner. Here, researchers intended to inspect the heat and mass transfer via nanofluid transported on an inclined permeable expanded sheet in the presence of solar thermal radiation without any barrier. Mainly, the formation of non-recovery energy called entropy and Joule heating are also weighed. The guiding non-linear partial differential equations were transformed into systems of non-linear higher-order ordinary differential equations by felicitous similarity transformation. They are solved by the prevalent technique called the Homotopy Analysis Method, which is executed by the BVPh2.0 package in Mathematica 12.1 software. Comparisons with preceding published articles confirm the method's validity and accent its admirable uniformity. Afterward, the magnetic field interaction delays the mobility of nanofluid while increasing the magnitude of local skin friction and temperature distribution. By intensifying the thermal radiation parameter and Eckert number, the temperature and entropy production escalated. Furthermore, the heat transfer by convective surpasses that of conductive owing to the particles' Brownian motion. Thermophoresis established surplus tiny-particles concentration. Heat transfer from solar radiation in moving nanofluids has been applicable for cooking, heating water, and producing electricity.

Assessment of magnetic field interactions and heating for cerebral aneurysm flow diverters during 7T MRI.

Flow diverters (FDs) are utilized for a wide range of aneurysms, but show safety issues such as adverse interactions with static magnetic fields (displacement force and torque) and radiofrequency-induced heating during magnetic resonance imaging (MRI). The present study aimed to assess these adverse interactions in a 7-tesla (7T) static magnetic field and radiofrequency-induced heating during a 7T MRI for two types of FD. Displacement force and magnetically induced torque were assessed using the deflection angle method and low friction surface method, respectively. To assess heating, each FD was set in a phantom filled with gelled-saline mixed with polyacrylic acid and underwent a 7T MRI using a three-dimensional fast spin echo method. Displacement force and magnetically induced torque in the 7T static magnetic field were undetectable, and radiofrequency-induced heating during 7T MRI remained ≤ 0.6 °C for both types of FD, suggesting that magnetic field interactions and heating on FDs during a 7T MRI are acceptable from a safety perspective.

Double Quantum Ring under an Intense Nonresonant Laser Field: Zeeman and Spin-Orbit Interaction Effects

We theoretically investigate the properties of an electron energy spectrum in a double GaAs-Al0.3Ga0.7As quantum ring by using the effective mass and adiabatic approximations, together with a realistic description of the confining potential profile, which is assumed to be deformed due to the application of an intense nonresonant laser field. The effects of the applied magnetic field and spin-orbit interaction are included. We discuss the features of the lowest confined energy levels under a variation of magnetic field strengths and intense laser parameters. The influence of this external probe on the linear optical absorption response associated with interlevel transitions is analyzed by considering both the presence and absence of spin-orbit effects.

Goldstone Mode of Skyrmion Crystal

We discuss the Goldstone mode of skyrmion crystal in a model of two-dimensional ferromagnet with the Dzyaloshinskii–Moriya interaction in magnetic field. We use stereographic projection approach to construct skyrmion crystal and consider skyrmion displacement field. The small overlap of the individual skyrmion images restricts the potential energy to the interaction of nearest neighboring displacements. The closed form of the Goldstone mode dispersion is found and its dependence on the magnetic field is studied. We use semiclassical quantization to define the Green’s function and show that the propagation of displacements through the crystal changes its tensorial form from anisotropic to isotropic one at large times.

Deformation transients of confined droplets within interacting electric and magnetic field environment

A theoretical exploration and an analytical model for the electro-magneto-hydrodynamics (EMHD) of leaky dielectric liquid droplets suspended in an immiscible confined fluid domain have been presented. The analytical solution for the system, under small deformation approximation in the creeping flow regime, has been put forward. The study of droplet deformation suggests that its temporal evolution is exponential and dependent on the electric and magnetic field interaction. Furthermore, the direction of the applied magnetic field relative to the electric field determines whether the magnetic force opposes or facilitates the interfacial net electrical force caused by the electric field. Validation of the proposed model at the asymptotic limits of vanishing magnetic field shows that the model accurately reduces to the case of the transient electrohydrodynamic model. We also propose a magnetic discriminating function (ϕM) to quantify the steady-state droplet deformation in the presence of interacting electric and magnetic fields. The change of droplets from a spherical shape to prolate and oblate spheroids corresponds to ϕM> 0 and < 0 regimes, respectively. It is shown that a substantial augmentation in the deformation parameter and the associated EMHD circulation within and around the droplet is achieved when aided by a low-magnitude magnetic field. The analysis also reveals the deformation lag and specific critical parameters that aid or suppress this lag behavior, discussed in terms of relevant non-dimensional parameters.

Momentum, heat and mass transfer in the hydrodynamic electrically conducting fluid flow over a stretching sheet

This study looks at the numerical results of magnetohydrodynamic liquid flowing across a stretching sheet at its stagnation point while also experiencing chemical reaction, viscous dissipation, thermal radiation and variable magnetic field. The fundamental partial differential equations that regulate physical phenomena are converted into nonlinear ordinary differential equations by using the appropriate similarity transformations. Later, resolved by numerically using Mathematica. The effects of various non-dimensional parameters like velocity ratio parameter ([Formula: see text]), porosity (k), magnetic parameter (M), radiation parameter (R), chemical reaction parameter ([Formula: see text]), etc. on the velocity, temperature and concentration profiles as well as on the local skin-friction and the local Nusselt number are discussed in detail and displayed through graphs. The numerical evaluation of the physical quantities was provided in tabular form for the various values of the relevant stream parameters. It is important to note that magnetic field interaction increases concentration distribution and fluid temperature while decreasing velocities at all domain flow locations.

SOME PHYSICAL CHARACTERISTICS OF A FIVE-DIMENSIONAL MASS SCALAR ELECTROMAGNETIC COSMOLOGICAL MODEL

In this paper we are interested to study some important physical aspects of a five dimensional space time which is attained by the interaction of magnetic field and zero mass scalar field in Einstein’s theory of gravitation, where the cosmic parameters X & A are functions of cosmic time t .The concluding remark is focused on the singularity nullity, uniformity, energy condition and about the possession of gravitational field radiation of the space-time.

Accretion Spin-up and a Strong Magnetic Field in the Slow-spinning Be X-Ray Binary MAXI J0655-013

We present Monitor of All-sky X-ray Image (MAXI) and Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the Be X-ray binary, MAXI J0655−013, in outburst. NuSTAR observed the source once early in the outburst, when spectral analysis yields a bolometric (0.1–100 keV), unabsorbed source luminosity of L bol = 5.6 × 1036 erg s−1, and a second time 54 days later, by which time the luminosity had dropped to L bol = 4 × 1034 erg s−1 after first undergoing a dramatic increase. Timing analysis of the NuSTAR data reveals a neutron star spin period of 1129.09 ± 0.04 s during the first observation, which decreased to 1085 ± 1 s by the time of the second observation, indicating spin-up due to accretion throughout the outburst. Furthermore, during the first NuSTAR observation, we observed quasi-periodic oscillations (QPOs) with centroid frequency ν 0 = 89 ± 1 mHz, which exhibited a second harmonic feature. By combining the MAXI and NuSTAR data with pulse period measurements reported by Fermi/GBM, we are able to show that apparent flaring behavior in the MAXI light curve is an artifact introduced by uneven sampling of the pulse profile, which has a large pulsed fraction. Finally, we estimate the magnetic field strength at the neutron star surface via three independent methods, invoking a tentative cyclotron resonance scattering feature at 44 keV, QPO production at the inner edge of the accretion disk, and spin-up via interaction of the neutron star magnetic field with accreting material. Each of these result in a significantly different value. We discuss the strengths and weaknesses of each method and infer that MAXI J0655−013 is likely to have a high surface magnetic field strength, B s > 1013 G.

A peculiar topological Hall effect in noncentrosymmetric ternary carbide GdCoC2

A peculiar topological Hall effect (THE) is reported in a noncentrosymmetric ternary carbide GdCoC2. The GdCoC2 reveals a magnetic ordering transition from paramagnetic to ferromagnetic state at the Curie temperature TC = 15.6 K, followed by a commensurate-incommensurate phase transition at Tt = 14.1 K. Below Tt, the competition between an external magnetic field and magnetic interactions, including the Dzyaloshinskii–Moriya interaction, would give rise to characteristic spin textures with non-zero scalar spin chirality χijk, or even topologically protected spin configurations like skyrmions, for which the exotic spin-charge coupled phenomena are induced. Besides a large negative magnetoresistance (MR) up to ∼−52% at 14 K, a remarkably sharp topological Hall signal is observed with almost no anomalous Hall resistivity below 10 K. The topological Hall resistivity (ρxyT) of GdCoC2 reaches a maximum value of ∼0.23 μΩ cm at 3 K under μ0H = 0.6 T. The mechanism underlying the exceptional THE with relatively large ρxyT value in GdCoC2 is discussed in detail.

Magnetocaloric effect in the Jx−Jy Blume–Capel model

The magnetocaloric properties of the Jx−Jy Blume–Capel model with Jx/Jy=−0.5 are studied using the two point approximation of the Cluster Variation Method. The phase diagrams exhibit different phases depending on the anisotropy parameter, magnetic field, temperature and exchange interaction ratio. It is shown how the nature of the phase transition changes as parameters are varied. For an anisotropy parameter value of D=1.45, a tricritical point and a reentrant behavior are identified. It was found inverse and direct magnetocaloric effect. The inverse magnetocaloric effect of the model is enhanced at low fields and temperatures around jumps between plateaus of magnetization.

Role of particle shape considering three-dimensional flow of water-based ternary hybrid nanofluids for the interaction of magnetic field

In developing current flow phenomena, the proposed study is carried out by the consideration of ternary hybrid nanofluid flow past a stretching surface. The flow became electrically conducting due to the inclusion of transverse magnetic field along the normal direction of the flow. Further, the energy profile is enhanced for the interaction of the radiative heat using Rosseland approximation. The innovation behind this approach is due to the assumption of the various shapes of the particles, i.e. spherical, cylindrical along with platelet-shaped nanoparticles and the corresponding physical properties are demonstrated. In view of physical phenomena, carbon nanotube, graphene, and aluminum oxide nanoparticles with water as a base liquid are used to prepare the hybrid nanofluid. Because of the complexity of the formulated model, the governing non-dimensional set of equations is handled by using traditional numerical technique following shooting-based “Runge–Kutta fourth-order” technique. Further, the significant role of the pertinent factors involved in the flow phenomena is the case of ternary nanofluid overshoots the fluid velocity in comparison to the case of nanofluid and hybrid nanofluid and the shear rate enhances for the increasing magnetization whereas the heat transfer rate attenuates significantly.

Quantum entanglement in an extended Hubbard model as evaluated from a spin concurrence measure

Quantum entanglement is a peculiar feature of quantum mechanics that turns out a powerful resource in quantum communication and information. For this reason, intense research has recently focused on the robustness of quantum entanglement also in strongly correlated electron systems. Here, we consider an extended Hubbard model on a dimer and evaluate the spin entanglement at finite temperature, under the action of an external magnetic field. We show how magnetic field and Coulomb interactions modify the spin concurrence, finding out that the magnetic field may act as a switch from a non-entangled to an entangled state.

The Effect of Resveratrol and Static Magnetic Field Interactions on the Oxidation–Reduction Parameters of Melanoma Malignant Cells

Background: Scientific research has confirmed the biological activity of resveratrol, which includes its antioxidant, anti-inflammatory, cardioprotective and anticancer properties. There is no known interaction between a static magnetic field and resveratrol that can modulate resveratrol’s effect on cells. Thus, the main aim of our research was to assess the effect of the co-exposure to resveratrol and a static magnetic field on the oxidation–reduction homeostasis of C32 and Colo829 melanoma cells. Methods: The studies consisted of determining the activity of the antioxidant enzymes that constitute the body’s first line of defense—SOD, GPx and CAT—and determining the lipid peroxidation product—MDA—and the value of the total antioxidant status of melanoma cells. Results and conclusions: Resveratrol was shown to exhibit anticancer properties, possibly through the ferroptosis of melanoma cells. A static magnetic field was also found to abolish the anticancer properties of resveratrol and to have a protective effect against melanoma cells by restoring the redox balance in the cells.