Influence Of Strong Magnetic Field Research Articles

Strong influence of magnetic field and non-uniform stress on elastic modulus and transition temperatures of twinned Ni–Fe(Co)–Ga alloy

The magnetization value and electric resistivity of the single-crystalline sample of Ni50Fe19Co4Ga27 shape memory alloy were measured. The elastic modulus was determined by the Dynamic Mechanical Analysis (DMA). The characteristic temperatures of martensitic transformation (MT) of the alloy were estimated from the temperature dependences of magnetization, electric resistivity and elastic modulus. A significant disparity between MT temperatures resulting from DMA and those estimated from magnetic and resistivity measurements was discovered. It was argued that the discrepancy is caused by the non-uniform mechanical stressing of twinned single crystal by the DMA analyzer. Moreover, the DMA measurements revealed a significant decrease of the elastic modulus of twinned martensite under the applied magnetic field of 1.5 kOe. To explain this effect, the temperature-dependent Young’s modulus of twinned crystal lattice was computed. The computations showed that the experimentally observed field-induced change of the elastic modulus is caused by the stress-assisted detwinning of the crystal lattice by the applied magnetic field.

Comparison of magnetized thick disks around black holes and boson stars

Boson stars are considered as promising candidates for black hole mimickers. Similar to other compact objects they can form accretion disks around them. The properties of these disks could possibly distinguish them from other compact objects like black holes in future observations. Retrograde thick disks around boson stars and the influence of strong magnetic fields on them were already studied and it was shown that they can harbor very distinct features compared to black hole disks. However, the case of prograde thick disks is mostly unexplored, since they may appear much more similar to black hole disks. In this work we will investigate similarities and differences regarding prograde thick disks around non-selfinteracting rotating boson stars and rotating black holes. We assume thereby a polytropic equation of state and a constant specific angular momentum distribution of the disks. We classify the various conceivable boson star and black hole solutions by a dimensionless spin parameter a and compare their corresponding disk solutions. The influence of toroidal magnetic fields on the disks is analyzed by selected disk properties, as the rest-mass density distribution and the Bernoulli parameter. Disk solutions are characterized by their degree of magnetization represented by the magnetization parameter βmc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta _{mc}$$\\end{document}. We found that strong magnetic fields can strengthen the differences of disk solutions or oppositely even lead to a correlation in disk properties, depending on the spin parameter of the boson star and black hole solutions. We identify the vertical thickness of the boson star disks as the main differentiating factor, since for most solutions the vertical density distribution is far more outreaching for boson star disks compared to black hole disks.

Two-phase volume-averaged predictive theory of dilute ferrofluid spin-up flow in a rotating magnetic field

We have developed a parameter-free, two-phase, volume-averaged approach to predictively describe the spin-up flow of dilute, cluster-free ferrofluids excited by low-frequency rotating magnetic fields. Predictive validation of the model was performed through a thorough comparison with local velocity profile measurements, and it demonstrated its ability to capture the spin-up flow dynamics without the need for parameter tuning by carefully delineating the validity domain of the ferrofluid dilutedness conditions. To gain insight into the underlying flow mechanisms, we performed a systematic parametric analysis examining the effects of the induced magnetic field, the dipolar interactions between magnetic nanoparticles and the demagnetizing field. How these mechanisms shape the flow of dilute ferrofluids excited by low-frequency rotating fields in a standard spin-up flow geometry has been addressed using probabilistic nanoparticle orientational dynamics, combining Faxén's laws and the Smoluchowski equation to describe the transport of particle magnetic moments. Our findings revealed that the induced magnetic field is the primary driving force of ferrofluid spin-up flow. The dipole interactions and demagnetizing field, on the other hand, contribute only as secondary phenomena to the overall flow behaviour. Furthermore, we have discussed the potential extension of the two-phase approach, in particular with respect to the formation of chain-like aggregates under the influence of strong magnetic fields. Overall, our study provides valuable insights into the complex dynamics of ferrofluid flow and contributes to a comprehensive understanding of the key mechanisms governing the spin-up flow of dilute ferrofluids excited by low-frequency rotating magnetic fields.

Numerical simulations of flow past a backward-facing step under a strong transverse magnetic field

The flow of liquid metal over a backward-facing step (BFS) exhibits unique flow characteristics due to the influence of strong magnetic field. In this study, direct numerical simulation of the BFS flow under a strong magnetic field is conducted based on a quasi-two-dimensional model (with a large interaction number, N≫1, and a large Hartmann number, Ha≫1). The Reynolds number (Re), Hartmann number (Ha), and expansion ratio (ER) are investigated within the ranges of [100−80 000], [100−40 000], and [1.67−5], respectively. Three typical flow regimes are defined based on the evolution of the free shear layer vortices and the separation state of the boundary layer. Furthermore, a comprehensive flow regime map is presented for different ER, revealing a positive correlation between the critical Reynolds number (Rec1) and Ha at the onset of instability. Specifically, Rec1 is proportional to Ha0.5, Ha0.54, and Ha0.56 for ER = 5, 2.5, and 1.67, respectively. Moreover, the maximum relative thickness of the free shear layer at Hac1 appears in the range of approximately 0.7–0.78Lr for ER = 5, while for ER = 2.5, it appears in the range of approximately 0.80–0.85Lr, indicating that the instability position of the free shear layer occurs earlier for large ER. Our numerical investigation also demonstrates that an increase in the transverse magnetic field compresses the free shear layer and delays the process of vortex pairing, thereby suppressing the oscillatory behavior of the shear layer.

Magnetically Enhanced Thin‐Film Coarsening by a Magnetic XPFC Model Allowing to Decouple Magnetic Anisotropy and Magnetostriction

External magnetic fields provide a macroscopic control mechanism to influence the microstructure of polycrystalline materials. Herein, the influence of strong magnetic fields on grain growth in thin films is modeled with a magnetic extended phase field crystal model. The magneto–structural effects are incorporated into the correlation function in reciprocal space. With this approach, magnetic anisotropy, magnetostriction, and mobility of grain boundary can be controlled and a variety of geometrical and topological properties consistent with experimental results can be determined.

Measuring the Influence of Magnetic Vestibular Stimulation on Nystagmus, Self-Motion Perception, and Cognitive Performance in a 7T MRT.

Strong magnetic fields induce dizziness, vertigo, and nystagmus due to Lorentz forces acting on the cupula in the semi-circular canals, an effect called magnetic vestibular stimulation (MVS). In this article, we present an experimental setup in a 7T MRT scanner (MRI scanner) that allows the investigation of the influence of strong magnetic fields on nystagmus as well as perceptual and cognitive responses. The strength of MVS is manipulated by altering the head positions of the participants. The orientation of the participants' semicircular canals with respect to the static magnetic field is assessed by combining a 3D magnetometer and 3D constructive interference in steady-state (3D-CISS) images. This approach allows to account for intra- and inter-individual differences in participants' responses to MVS. In the future, MVS can be useful for clinical research, for example, in the investigation of compensatory processes in vestibular disorders. Furthermore, it could foster insights into the interplay between vestibular information and cognitive processes in terms of spatial cognition and the emergence of self-motion percepts under conflicting sensory information. In fMRI studies, MVS can elicit a possible confounding effect, especially in tasks influenced by vestibular information or in studies comparing vestibular patients with healthy controls.

Preface

The 2022 8th International Forum on Manufacturing Technology and Engineering Materials (IFEMMT 2022) was successfully held on October 14th-16th, 2022 in Chongqing, China (virtual conference). IFEMMT 2022 brought together academics and experts in the field of Manufacturing Technology and Engineering Materials to a common forum, making it a great platform for people to share views and experiences in related areas.We were honored to have Prof. Xiansheng Ning from Shenyang Ligong University, China to serve as our General Conference Chair. The conference covered keynote speeches, oral presentations, and online Q&A discussion, attracting 150 individuals. Firstly, keynote speakers were each allocated 30-45 minutes to hold their speeches. Then in the oral presentations, the excellent papers selected were presented by their authors in sequence.During the conference, five sophisticated professors were invited to make keynote speeches. Among them, Prof. Vijay Kumar Thakur from Scotland’s Rural College delivered a keynote speech on Polymer Nanocomposites as Promising Materials for the Future. Polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. The combination of both the polymers and fillers provides enhanced properties depending on the type and nature of polymer matrices as well as fillers. Therefore, this presentation mainly discussed about the work on the synthesis and processing of polymer-based materials for advanced application. Additionally, Assoc. Prof. Xiao Lu from Shenyang Ligong University made a report on Structure Design of Defective Electrocatalysts and Effect of High Magnetic Field on Electrocatalysis Process. The report proposed a method to achieve high efficiency oxygen reduction reaction by regulating the defect structure of carbon materials and metal catalyst materials and put forward the preparation of catalyst materials under strong magnetic field and the influence of strong magnetic field on oxygen evolution reaction and oxygen reduction reaction process. Their excellent presentations had sparked heated discussion in the conference. Moreover, every participant praised this conference for disseminating insightful knowledge.After months of well preparation and hard work, the proceedings of IFEMMT 2022 covering a bunch of papers are smoothly published. These papers feature but are not limited to the following topics: Advanced Design Technology, Manufacturing Systems and Automation, New Materials and Advanced Materials, etc. All the papers have been checked through rigorous review and processes to meet the requirements of publication.We would like to express our heartfelt appreciation to all the keynote speakers, peer reviewers, and all the participants. Particularly, we would like to acknowledge the Journal of Physics: Conference Series, for the endeavor of all its colleagues in publishing this paper volume. We are sure that IFEMMT 2022 will contribute to not only scientific and engineering progress but also other new products and processes.The Committee of IFEMMT 2022List of Committee member is available in this Pdf.

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.

Quark matter phase diagram under the influence of strong magnetic fields with a nonlocal chiral model

AbstractWe study the phase diagram in the T − μ plane for quark matter under the influence of a strong uniform magnetic field , in the framework of a non‐local extension of the two‐flavor Polyakov–Nambu–Jona‐Lasinio model. We analyze the deconfinement and chiral symmetry restoration transitions in the mean field approximation. For the considered parameterization, it is found that there is always a critical end point (CEP) in the T − μ plane that separates a first‐order transition line from a smooth crossover. The location of the CEP is studied as a function of the magnetic field.

Properties of Strange Quark Matter in the Context of Diquark Correlation

AbstractProperties of strange quark matter (SQM) have been studied as diquark matter with diquark correlation. The dense SQM is under strong magnetic field due to electroweak interaction of quarks. Here it is suggested that u, d, s quarks get correlated to form diquark matter of different flavors. The diquarks are suggested to behave like quasiparticles under the influence of strong magnetic field inside the dense quark matter. In the current work diquarks are described as the composite fermions which behave like quasiparticle under the strong magneticfield in an analogy with the electrons behaving in strong magnetic field. The thermodynamic potential for SQM has been estimated and behavior is studied with respect to chemical potential. The equation of state and the velocity of sound through SQM are also studied. Some interesting observations are made. It is suggested that the composite fermion picture of diquark correlation lowers the binding energy of the system making the SQM a more stable state.

Exploring the effects of Δ baryons in magnetars

Strong magnetic fields can modify the microscopic composition of matter with consequences on stellar macroscopic properties. Within this context, we study, for the first time, the possibility of the appearance of spin-3/2 $\Delta$ baryons in magnetars. We make use of two different relativistic models for the equation of state of dense matter under the influence of strong magnetic fields considering the effects of Landau levels and the anomalous magnetic moment (AMM) proportional to the spin of all baryons and leptons. In particular, we analyze the effects of the AMM of $\Delta$ baryons in dense matter for the first time. {We also obtain global properties corresponding to the EoS models numerically and study the corresponding role of the $\Delta$ baryons.} We find that they are favored over hyperons, which causes an increase in isopin asymmetry and a decrease in spin polarization. We also find that, contrary to what generally occurs when new degrees of freedom are introduced, the $\Delta$s do not make the EoS significantly softer and magnetars less massive. Finally, the magnetic field distribution inside a given star is not affected by the presence of $\Delta$s.

Quasi-linearization analysis for heat and mass transfer of magnetically driven 3rd-grade (Cu-TiO2/engine oil) nanofluid via a convectively heated surface

The features of heat transferral capability between metallic (Cu) and non-metallic (TiO2) nanoparticles suspended in the engine-oil (EO) third-grade base-liquid has been analysed under the influence of strong magnetic field. The numerical investigation of system of coupled differential equations for third-grade nanofluid flow model is accomplished via Quasi-linearization method (QLM). The stretching horizontal sheet is heated through convective heat process assuming the special effects of thermal radiation, joule heating, heat generation and viscous dissipation in the energy equation. The mass suction and slip velocity at the boundary of the sheet has been taken into account to enhance fluidity of the engine-oil nanofluid. The prominent non-dimensional parameters controlling the flow and heat transfer characteristics of Cu-TiO2/ Engine-Oil nanofluid are estimated through graphical and tabular data. A novel graphical analysis for entropy generation versus magnetic retardation is projected for various parameters. Entropy generation is reduced by the velocity slip parameter but it is increased by the Reynolds number and Brinkman number. The enhanced lubricating properties of engine oil with mixing of TiO2-nanoparticles might be a useful industrial lubricant for magnetic refrigeration applications.

Development and Implementation of Smart Water Metering System based on Lora Technology

The article presents an overview of traditional water meters in Vietnam, digitizing metrology technologies and wireless data transmission technology for data collection and user applications in smart water metering systems. After that, it is proposed to design a smart wireless water meter module. This paper focuses on designing and implementing a smart water meter to re-use traditional mechanical water meters by designing a smart water metering module attached to the existing meter. This way, it eliminates the costs of investing in flow water meter and influences the old water meter infrastructure system. The contribution of this paper is threefold: (i) Firstly, it proposes wireless data transmission and digitizing metrology technologies suitable for water metering systems in Viet Nam. (ii) Secondly, the proposed smart water meter module designs include hardware, firmwave, and plastic cover. There are two experimental prototypes of the module is introduced in this paper (iii) Lastly, The paper provides a water metering management software model for smart cities. And the overall systems of the proposed platform were built to verify the presented design. To reduce the amount of water leaking or users hacking from outside the meter in the measurement results, the article proposes to design features to alert about: abnormal flow, strong magnetic field influence, and equipment cover being removed. The experimental verification was designed with the Actaris water meter using Hall technology to digitize data and the Itron water meter with digitizing technology using the LC sensor. Besides, the Lora wireless network system is proposed and deployed to verify the water metering management with the advantages of low energy consumption, high security, and strict authentication process. Actual results for the laboratory environment and residential areas show that signal loss (RSSI) and signal noise (SNR) is within the allowable range. In addition, the packet loss rate <1% and average power consumption meter <50uA. Water metering management software is presented to verify the smart city service system.

Thermomagnetic characterization of Ising-type ferromagnets of spins S=5/2 and σ=7/2: a Monte Carlo study

In this investigation through of Monte Carlo simulations we characterize thermomagnetically two Ising type ferromagnetic models of spins S = ±5/2, ±3/2, ±1/2 and σ = ±7/2, ±5/2, ±3/2, ±1/2 located alternately in a square lattice, formed by two sublattices A and B each with 120 sites containing the spins S and σ, respectively. The ferromagnetic configurations studied are defined by and H1 and H2 Hamiltonians with next neighbors and next nearest neighbors exchange interactions, and single ion anisotropy and external magnetic field interactions. The thermomagnetic analysis of the system defined by H1 Hamiltonian shows discontinuities in the magnetization, as well as a strong influence of magnetic field on the critical and discontinuous transition temperatures. For the case of the ferromagnet defined by H2 Hamiltonian, after analyzing the effects of the next nearest neighbors interactions and magnetic field, we find an almost linear dependence on the critical temperature. The study of hysteresis behavior in both ferromagnets shows the phenomenon of exchange bias.

Structure of ultra-magnetised neutron stars

In this review we discuss self-consistent methods to calculate the global structure of strongly magnetised neutron stars within the general-relativistic framework. We outline why solutions in spherical symmetry cannot be applied to strongly magnetised compact stars, and elaborate on a consistent formalism to compute rotating magnetised neutron star models. We also discuss an application of the above full numerical solution for studying the influence of strong magnetic fields on the radius and crust thickness of magnetars. The above technique is also applied to construct a “universal” magnetic field profile inside the neutron star, that may be useful for studies in nuclear physics. The methodology developed here is particularly useful to interpret multi-messenger astrophysical data of strongly magnetised neutron stars.

Martensitic transformation in the systems based on Fe-Ni compositions in strong pulsed magnetic fields

Purpose of work. To ascertain the causes of the abnormally large displacement of the martensitic point in steels and iron alloys in strong pulsed magnetic fields at low temperatures. Research methods. Generalization of experimental and theoretical investigations of the strong magnetic field influence on the martensitic transformation in steels and iron alloys, taking into account the magnetic state of austenite. The obtained results. The distributions of the martensitic point displacement ΔMS from the content of the main component - iron and the temperature of the martensitic γ → α- transformation beginning (martensitic point MS) in different experiments are obtained. It is shown that the obtained temperature dependence ΔMS(MS) in a strong magnetic field at low temperatures decomposes into two components, one of which correlates with the generalized Clapeyron-Clausius equations, and the other is opposite to it. In addition, it was found that steels and alloys with intense γ → α- transformation in a magnetic field contain at least 72.5% iron (wt), which at low temperatures in the fcc structure is antiferromagnetic. Scientific novelty. The anomalous temperature dependence of the distribution ΔMS(MS) in a strong magnetic field is explained on the basis of quantum representations of the magnetic interaction of atoms in the Fe-Ni system. This effect is associated with a number of other invar effects, in particular, with an abnormally large spontaneous and forced magnetostriction, a strong dependence of the resulting exchange integral on the interatomic distance. The point of view according to which in these alloys in a magnetic field γ → α- transformation occurs by the type of “magnetic first kind phase transformation” is substantiated. It is assumed that the nucleation of the martensitic phase in a magnetic field occurs in (at) local regions of γ- phase with disoriented atomic magnetic moments (with high compression and increased forced magnetostriction). Practical value. The information obtained in this work provides grounds for explaining the kinetic features of the transformation of austenite into martensite in steels and iron alloys.

Viscous properties of hot and dense QCD matter in the presence of a magnetic field

We have studied the effect of strong magnetic field on the viscous properties of hot QCD matter at finite chemical potential by calculating the shear viscosity (eta ) and the bulk viscosity (zeta ). The viscosities have been calculated using the relativistic Boltzmann transport equation within the relaxation time approximation. The interactions among partons are incorporated through their quasiparticle masses at finite temperature, strong magnetic field and finite chemical potential. From this study, one can understand the influence of strong magnetic field and the influence of chemical potential on the sound attenuation through the Prandtl number (Pl), on the nature of the flow by the Reynolds number (Rl), and on the relative behavior between the shear viscosity and the bulk viscosity through the ratio zeta /eta . We have observed that, both shear and bulk viscosities get increased in the presence of a strong magnetic field and the additional presence of chemical potential further enhances their magnitudes. With the increase of temperature, eta increases for the medium in the presence of a strong magnetic field as well as for the isotropic medium in the absence of magnetic field, whereas zeta is found to decrease with the temperature, contrary to its increase in the absence of magnetic field. We have observed that, the Prandtl number gets increased in the presence of strong magnetic field and finite chemical potential as compared to that in the isotropic medium, but it always remains larger than unity, thus instead of the thermal diffusion, the momentum diffusion largely affects the sound attenuation in the medium and this is more vigorous in the presence of both strong magnetic field and finite chemical potential. However, the Reynolds number becomes lowered than unity in an ambience of strong magnetic field and even gets further decreased in an additional presence of chemical potential, thus it implies the dominance of kinematic viscosity over the characteristic length scale of the system. Finally, the ratio zeta /eta is amplified to the value larger than unity, contrary to its value in the absence of magnetic field and chemical potential where it is less than unity, thus it is inferred that the bulk viscosity prevails over the shear viscosity for the hot and dense QCD matter in the presence of a strong magnetic field.

Asymmetrical Thermal Boundary Condition Influence on the Flow Structure and Heat Transfer Performance of Paramagnetic Fluid-Forced Convection in the Strong Magnetic Field

Continuous interest in space journeys opens the research fields, which might be useful in non-terrestrial conditions. Due to the lack of the gravitational force, there will be a need to force the flow for mixing or heat transfer. Strong magnetic field offers the conditions, which can help to obtain the flow. In light of this origin, presented paper discusses the dually modified Graetz-Brinkman problem. The modifications were related to the presence of the magnetic field influencing the flow and asymmetrical thermal boundary condition. Dimensionless numerical analysis was performed, and two dimensionless numbers (magnetic Grashof number and magnetic Richardson number) were defined for paramagnetic fluid flow. The results revealed the heat transfer enhancement due to the strong magnetic field influence accompanied by possible but not essential flow structure modifications. On the other hand, the flow structure changes can be utilized to prevent the solid particles’ sedimentation. The explanation of the heat transfer enhancement including energy budget and vorticity distribution was presented.

Liquid metal MHD effect and heat transfer research in a rectangular duct with micro-channels under a magnetic field

The liquid metal blanket of a fusion reactor acts the role of tritium multiplication and energy transportation in a strong magnetic field environment. Liquid metal in fusion blanket is different from traditional flow and heat transfer due to magneto hydrodynamics (MHD) effects. A numerical simulation is employed to investigate the convection heat transfer between liquid metal and micro-channels heated surface under an external magnetic field. It can be found that under the influence of magnetic field, liquid metal can produce strong jet near the wall which drives the liquid metal flow together inside the channel. The MHD Hunt flow effect is intensified with the enhancement of the magnetic field and the results indicate that the magnetic field is beneficial to the energy transport and conversion of liquid metal blanket due to the jet flow on the wall that caused by the magnetic field. From the point of view of enhanced heat transfer, 32% of the heat transfer enhancement under the influence of strong magnetic field provides a new way to solve the heat transfer with high heat flux density. The expression is fitted between Nu number with Re number, the magnetic interaction number and flow distance, which can be used to predict the change of heat transfer intensity between the liquid metal and the micro-channels heated plate with the magnetic field intensity.

A study on influence of strong magnetic field on fracture of interface crack considering magneto-elastic coupling effects

The influence of strong magnetic field on stress intensity factor of an interface crack is studied in this paper. The nonlinear piezomagnetic property and magnetostriction effect have been taken into consideration in the theoretical analyses. This multi-field coupled problem is solved through a sequential coupling approach. The perturbed magnetization caused by the deformation around the crack is solved under magnetic boundary conditions. After modified by the perturbed magnetization, the initial loads are updated with magnetic forces for iterative calculation. With this strategy, the distributions of the stress and displacement at the crack region approach to the real solution gradually. Numerical results show that the influence of the external magnetic field on fracture behaviors is not ignorable. For structures with interface crack serving in a strong magnetic field, e.g., the multi-layer welded structures in the Tokamak device, the magneto-elastic coupling effects have to be considered to deal with its fracture problem.