Induced Magnetic Field Research Articles

Моделирование мультикасповой магнитной системы источника ускоренных нейтральных частиц

The article considers the solution of an important technological problem of cleaning dielectric surfaces, during which the formation of a surface potential is eliminated, requiring the development of specialized sources of accelerated neutral particles integrated into ion-plasma installations. A significant disadvantage of these sources is the low density and poor uniformity of the output flow, which leads to an increase in the time of the technological operation and deterioration in the quality of surface treatment. To eliminate these disadvantages, a multicusp magnetic field system can be integrated into the device to reduce the plasma load on the anode, reduce the effective area of the anode and increase the density of the vapor-plasma flow. To optimize the design of the source, a simulation of the magnetic system was carried out and the calculation of the distribution of the magnetic field in the working area was conducted. For optimal operation of the source, it is necessary to achieve the largest possible magnitude of magnetic field induction at the walls of the working volume and as small as possible in the central region in which the vapor-plasma flow moves. The simulation results show that there is an optimal solution when choosing the number of permanent magnets holding the gas-discharge plasma. The retention effect increases with an increase in the number of permanent magnets, while the output of electrons from the loss cone becomes more frequent, which leads to a deterioration in the quality of the output flow. The optimal number of magnets is selected from the condition of balancing these two competitive effects.

Explicit and unconditionally stable finite-difference time-domain subgridding algorithm based on hanging variables

Due to the limitation of the stability condition, the finite-difference time-domain (FDTD) method cannot efficiently deal with electromagnetic problems containing fine structures. The explicit and unconditionally stable (EUS) FDTD method can eliminate the constraint of the stability condition and improve the simulation efficiency of fine structures by filtering out the unstable modes for the system matrix. However, the EUS-FDTD method needs to solve the eigenvalues of the numerical system matrix, and the symmetry of the numerical system matrix needs to be ensured when the subgridding scheme is used to discretize targets containing fine structures. The existing EUS-FDTD subgridding method encounters some problems such as complex implementation and insufficient accuracy. In order to solve the above problems, in this work, the hanging variables subgridding (HVS) algorithm is applied to the EUS-FDTD algorithm. Starting from the symmetry of the system matrix, the stability of the hanging variables subgridding algorithm is proven, and a high-precision, stable, and easy-to-implement HVS-EUS-FDTD scheme is proposed. Numerical examples of the radiation of linear magnetic currents in free space, electromagnetic scattering of multiple dielectric objects, and a three-dimensional cavity containing a medium demonstrate the stability, high accuracy and efficiency of the proposed method. Numerical experiments show that the computational efficiency of the HVS-EUS-FDTD algorithm can be improved hundreds of times compared with that of the uniform fine grid FDTD algorithm, and the highest computational efficiency can be improved up to ratio (the size ratio of coarse grid to fine grid) times compared with that of the HVS-FDTD algorithm.

Enhancing efficiency of magnetic energy by implementing square-shaped materials adjacent to induction machine windings

This study provides a worthwhile method for increasing the magnetic field energy and induction machine (IM) effectiveness. The coupling between the transmitter and receiver windings in the IM system can be improved by creating materials with specific electromagnetic properties. This added material has altered the magnetic flow as well as the energy of the magnetic field. Eventually, it is possible to calculate the efficiency of the magnetic field, or the ratio of primary to secondary magnetic energy. With the use of two-dimensional finite element analysis, numerical results on five cases with various configurations of a magnetic substance have been produced. This material, which varies in length or breadth, is positioned close to the windings of the transmitter, receiver, or both. Case 3, in which the transmitter generates a magnetic field on the receiver side with a minimum energy of 0.05 J and a maximum energy of 0.015 J, is the ideal material configuration for DC current. Currently, the system efficiency is 0.29 on average. A 1 kHz transmitter's energy is constant under all conditions, but its counterpart's energy fluctuates significantly, with case 5 receiving the most energy. Therefore, case 5 turns into the optimal structural arrangement. It can be inferred that case 5 similarly dominates the other with an efficiency of 0.0026, which is much greater than that of 1 kHz efficiency, while the windings are operating at 1 MHz. This leads to stronger magnetic field coupling and increased power transfer effectiveness.

A simple yet efficient solution for TE scattering from a right trapezoidal groove

AbstractA simple yet efficient solution to the problem of transverse electric (TE) scattering by a two‐dimensional right trapezoidal groove placed in a perfect electric conductor (PEC) surface is presented. Using superposition of plane waves and applying the Neumann boundary condition at the groove walls, the transverse magnetic field is expressed as the sums of infinite series of waveguide modes. Considering the equivalent magnetic current on the aperture, a Fredlholm's integral equation with logarithmic singular kernel is extracted and then discretised by a collocation method based on a piecewise constant approximant. The extracted linear system of equations can be easily solved by the matrix methods for the unknown coefficients. Numerous examples are presented to verify the results and show the ability of the proposed method. Finally, this method is employed to examine the effect of the groove parameters and incidence angle on the scattering signatures.

Parameter Optimization of Wireless Power Transfer Based on Machine Learning

Wireless power transfer (WPT) has become a crucial feature in numerous electronic devices, electric appliances, and electric vehicles. However, traditional design methods for WPT suffer from numerous drawbacks, such as time-consuming computations and high error counts due to inaccurate model parameters. As artificial intelligence (AI) continues to gain traction across industries, its ability to provide quick decisions and solutions makes it highly attractive for system optimizations. In this paper, a method for optimizing WPT parameters based on machine learning is proposed. The convolutional neural network is adapted for training and predicting the performance of a pair of coupled coils under a set of input parameters. The performance parameters include the spatial magnetic field distribution map, quality factor, inductance value, and mutual inductance value, which are critical in determining the efficiency and selecting optimal coil parameters such as the number of turns and wire diameter. Moreover, the spatial magnetic field distribution map is also helpful for identifying design compliance with the electromagnetic field safety standards. The training results reveal that the proposed method takes an average of 3.2 ms with a normalized image prediction error of 0.0034 to calculate the results to calculate one set of parameters, compared to an average of 23.74 s via COMSOL. This represents significant computational time savings while still maintaining acceptable computational accuracy.

(Digital Presentation) A Novel Method for Precise Measurement of Displacement Using Eddy Currents at High Temperature

In this paper, a novel method of measuring displacement using eddy currents at high temperature is presented. The measurement system consists of a sensing coil created on a PCB by patterns, a parallel turning circuit and a microcontroller including a signal processing unit. When the gap distance between the conductive target and the sensing coil changes, the inductance value of the coil varies by the influence of the eddy current. By detecting the change in the inductance, we have proposed a novel method to precisely measure the displacement of the coil. In order to make the optimal coil, a theoretical analysis was conducted using the inductance calculation theory, and the magnetic field distribution and inductance variation of the coil were analyzed using ANSYS Maxwell. Then, the coil was fabricated as a PCB, and the measured result value was compared with each analysis result, and the coil most suitable for the system was selected. The circuit was designed so that the characteristics of the synchronization amplification circuit in the detection system were minimized in temperature change, and the temperature characteristics were primarily corrected in hardware by adding a temperature correction circuit. The output value of the primarily corrected tuning amplification circuit improved the temperature characteristics of the sensor by secondarily correcting the temperature characteristics in firmware, and is designed to meet the IPC class 3 specification. The sensing range of the implemented measurement system was 0.0 ~ 3.8 mm, the nominal value of the fabricated sensing coil was 11.2uH, and the resonance frequency of the tuning circuit including the sensing coil was 300Khz. The operating temperature of the system is – 40 ~ 150 ℃ and the resolution is 0.15 mm within the range of 0.0 ~ 3.8 mm. From the experimental results, Comparing the change in inductance with respect to the moving distance of the measurement system and the displacement signal measured by the system, it can be seen that as the inductance increases, the displacement output increases, and as the inductance decreases, the displacement also decreases. Considering this, it was found through the system that inductance and output of displacement are correlated, and is seen operates stably at high temperature and has linearity. Figure 1

Interactions between several types of cosmic strings

We study the interaction of several types of static straight cosmic strings, including local strings, global strings, and bosonic superconducting strings with and without magnetic currents. First, we evaluate the interaction energy of two widely separated cosmic strings using the point source formalism and show that the most dominant contribution to the interaction energy comes from the excitation of the lightest mediator particles in a underlying theory. The interaction energy at arbitrary separation distances is then analyzed numerically by the gradient flow method. It turns out that an additional scalar field introduced in the bosonic superconducting string becomes an additional source of attraction. For such a bosonic superconducting string, we find that a string with two winding numbers is energetically favorable compared to two strings with a single winding number in a certain parameter region. Our analysis reveals that a phase structure of bosonic superconducting strings is richer than that of local and global strings and that the formation of bound states at intersections of bosonic superconducting strings is favored.

A flux pump driven non-soldering closed-loop HTS magnet and its electromagnetic-thermal semi-analytical modelling method

We propose a new flux pump driven non-soldering closed-loop (NSCL) high temperature superconducting (HTS) magnet free of any soldering joints throughout the magnet for persistent current mode (PCM) operation. All the superconducting parts of the magnet are wound directly with HTS closed-loop ring split from an 8 mm REBCO tape using our new cutting scheme free of any soldering requirements. The magnet contains two single-pancake coils connected in series forming a closed circuit through two parallel bridge branches. Two thermal switches set on the two bridge branches control the on–off of the two bridges. A copper coil with iron core installed around one of the bridges is employed as the flux pump to drive the HTS magnet. An electromagnetic-thermal semi-analytical modelling method is proposed to analyse the pumping process by which the transport current in the magnet is calculated. The theoretical limit equation of the saturation current is improved as well. The proposed method can predict the current of the NSCL HTS magnet during the pumping process and provide results that are close to experiments. Experiments verify both the feasibility of the proposed flux pump driven NSCL HTS magnet and the modelling method. The results show that the NSCL HTS magnet works well in the PCM, which provides inspiration to the design of PCM operation of high field HTS magnets. The proposed modelling method also helps guide the design of different forms of HTS magnets and the flux pumps driving them.

Low-dimensional magnetic centers in HTSC YBCO film on steel-276 induced by gamma-quanta and electron beam

Coated HTSC tapes of 2-generation based on YBa2Cu3O7-x film were irradiated with 5 MeV electron beam at 273 K to generate low-dimensional defects of atomic displacements in Cu and O sublattices for possible enhancing the magnetic flux pinning and thereby increasing the magnetic critical current. We found the optimal electron beam current and fluency, when the neighbouring linear defects are spaced so as to accommodate vortices in the undamaged superconducting area. The following 60Co gamma-irradiation at 77 K generates defect pairs and causes hole localization and increases magnetic induction. In the mixed vortex state the charge carrier pairing energy is higher than kT due to paramagnetic pinning at radiation induced defects in oxygen sublattice both in CuO chains and CuO2 planes. Such a radiation treatment of HTSC tapes is recommended for the electron beam focusing coils.

Significance of slip velocity and couple-stress fluid lubrication on experiencing object sphere subject to Lorentz forces

This study investigates the interaction between fluid dynamics and electromagnetic fields, a complex problem that has not been extensively studied. The Lorentz force, which arises due to the interaction between magnetic fields and currents in a fluid is considered in this study. This research investigates the effects of a magnetic field, couple stress, and slip velocity on the behavior of a squeeze film (SF) formed between a porous flat and spherical plate. The Stokes equation for couple stress fluids is used to produce a generalized version of the Reynolds equation, which is then used to determine the film pressure. Also, this study considers the impact of a constant magnetic field orthogonal to the plate. The fluid in the porous region is governed by modified Darcy law. The effect of a uniform magnetic field perpendicular to the plate is considered. The bearing characteristics pressure, squeeze film time, and load-carrying capacity are graphically presented. The results revealed that the load-carrying capacity, pressure, and squeeze film time are reduced with a rise in slip and porousness parameters. The slip parameter decreases the values of film pressure, squeeze time, and load-carrying capacity as related to the no-slip case.

Estimating the Inertia Tensor Components of an Asymmetrical Spacecraft When Removing It from the Operational Orbit at the End of Its Active Life

The paper presents a method for estimating the inertia tensor components of a spacecraft that has expired its active life using measurement data of the Earth’s magnetic field induction vector components. The implementation of this estimation method is supposed to be carried out when cleaning up space debris in the form of a clapped-out spacecraft with the help of a space tug. It is assumed that a three-component magnetometer and a transmitting device are attached on space debris. The parameters for the rotational motion of space debris are estimated using this measuring system. Then, the known controlled action from the space tug is transferred to the space debris. Next, measurements for the rotational motion parameters are carried out once again. Based on the available measurement data and parameters of the controlled action, the space debris inertia tensor components are estimated. It is assumed that the measurements of the Earth’s magnetic field induction vector components are made in a coordinate system whose axes are parallel to the corresponding axes of the main body axis system. Such an estimation makes it possible to effectively solve the problem of cleaning up space debris by calculating the costs of the space tug working body and the parameters of the space debris removal orbit. Examples of numerical simulation using the measurement data of the Earth’s magnetic field induction vector components on the Aist-2D small spacecraft are given. Thus, the purpose of this work is to evaluate the components of the space debris inertia tensor through measurements of the Earth’s magnetic field taken using magnetometer sensors. The results of the work can be used in the development and implementation of missions to clean up space debris in the form of clapped-out spacecraft.

Spacetime dynamics of chiral magnetic currents in a hot non-Abelian plasma

Spacetime dynamics of chiral magnetic currents in a hot non-Abelian plasma

Varying the energisation condition to mitigate sympathetic inrush current

Transformers are generally easy to access and can contribute significantly to entire power system. When a transformer is turned on for the first time, it produces a magnetising inrush current which acts as a starting current. Energisation of transformer has a substantial impact on inrush current and transformer that are connected in parallel. Sympathetic inrush current is a phenomenon that appears when a transformer is switched-on in network whereas the other transformers that was earlier energised. Besides, when sympathetic inrush phenomena occur, the peak and period fluctuate significantly. In this paper, the transformers will be energised in three different ways and each condition will be explored in depth. The operation time of the transformer’s energisation whether it is energised simultaneously or at different times are tested and analysed in terms of their characteristics. It is performed using power system computer aided design (PSCAD) software, starting with a develop model of the energisation and then generate the outcomes. The results of the simulation demonstrate that energising the transformer in different ways can give different effect on the sympathetic inrush current, as well as the variables that affect it and methods for reducing it.

Analysis of the Magnetic Field and Attractive Force of the Electromagnetic Separator Using the Finite Element Method

The paper provides an analysis of the magnetic field and the attractive electromagnetic force of a powerful electromagnet that is used as part of an electromagnetic separator (EMS) to separate metal parts on conveyor belts for coal delivery. The analysis was done using the finite element method using the FEMM 4.2 software package. For the modelling of the EMS magnetic circuit, a two-dimensional axis-symmetric model was defined and one characteristic section was simulated. Since a time-invariant magnetic field originating from a constant direct current is considered, a magnetostatic type of simulation is adopted. The paper presents the simulation results related to the value of the magnetic field induction and the attractive force of the electromagnet for several characteristic distances of interest. The results of the simulation were applied as part of the design if the plant for the detection and extraction of metal parts on the conveyor belt for the delivery of coal from surface mine “Drmno” to the thermal power plant (TPP) "Kostolac".

The Conceptual Design of An Electro-Magnetic Power Generator

Nowadays, magnetic field induction is a dependable renewable energy source that can convert magnetic fields into electrical power. In this study, our objective is to propose a low-cost free energy generator design based on neodymium. The main problems with existing generators were air pollution, noise pollution, and even fuel price volatility. To begin addressing this issue, we compared 6 currently used generators. We concentrated on 5 criteria in light of this outcome. Our top considerations in this study are cost and maintenance. Then comes the size, weight, and noise. The best electromagnetic power generators for satisfying all the criterion domains are determined using Pugh's matrix. It demonstrates that electromagnetic power generators have a high score of 95 compared to natural gas, portable, and diesel power generators. We have also calculated the resulting voltage from the selected number of permanent magnet coils. This calculation shows 60V resulting in 9600 turns. As a result, we draw the conclusion that the reduction of problems like noise and air pollution makes this power generator look like a very appealing alternative.

Magnetic‐field‐induced Fe3O4@CNTs/PES/SPSf composite membrane for efficient removal of methylene blue by adsorption and catalytic degradation

AbstractNovel composite membranes are successfully developed for adsorption and catalytic degradation of methylene blue (MB) by blending Fe3O4‐coated CNTs (Fe3O4@CNTs) nanoparticles in polyethersulfone (PES) and sulfonated polysulfone (SPSf) matrix via nonsolvent‐induced phase separation (NIPS) method assisted by magnetic field. Fe3O4@CNTs nanoparticles migrate to the separation layer under the induction of magnetic field, thus Fe3O4@CNTs/PES/SPSf composite membranes prepared under magnetic field exhibit a better dye removal ability compared with that without magnetic field. The MB removal ratio by Fe3O4@CNTs/PES/SPSf composite membrane containing 8 wt% Fe3O4@CNTs (M2−M) can reach up to 99% in 30 min under the conditions of 0.25 g composite membrane, 20 mg/L MB, 0.1 mol/L H2O2, pH = 3 and 80°C. Furthermore, the composite membranes show excellent recycling performance, as the MB removal capacity remains at 99% even after four cycles.

Smart controllable wave dispersion in acoustic metamaterials using magnetorheological elastomers

The success in the flexible design of smart acoustic metamaterials is crucially contingent upon the degree of control over the parameters that uniquely define the spectrum of band structure and morphology of dispersion surfaces. In this work, we have studied the driving physical mechanisms, the control of which makes possible operating, in real-time, on the set of band gaps formed in 3D metamaterials based on magneto elastomers. In such acoustic structures, the stiffness of the medium in which unit cells are immersed, as well as the stiffness of the shells surrounding multi-particle cores depend on the induction, B(t), of an external magnetic field. The results obtained are systematized through the qualitative analysis of diversе scenarios for the evolution of the frequency characteristics of the metamaterial and summarized in the following complete physical picture of their dynamics. Variation of the stiffness of the medium/shells changes the wavelength of the shell's surface waves at characteristic frequencies of the core vibrations and, as a result, the level of coupling between the vibration modes of the flexible shells and cores. Consequently, with an increase/decrease in the stiffnesses of the shells/medium, the dispersion surfaces of the entire acoustic system shift up/down along the frequency axis with noticeably different ‘mobilities’ that reversibly lead either to the formation of the band gaps in initially dense frequency spectrum or to the transformation of the band gaps formed into pass bands. The tuning of the set of dispersion surfaces depending on the range of changes in the magnetic field induction can be carried out in dynamic, quasi-stationary, and over-critical regimes when some of the dispersion surfaces degenerate into planes. In anisotropic metamaterials, simultaneously with creating full band gaps, it is possible to create tunable directional band gaps with adjustable frequency and angular widths. The results obtained, within the framework of the idealized discrete mass-spring model, are in good agreement with the data presented in the available experimental works and can be useful in the design of acoustic systems with desirable properties.

Analysis of deep drawing with electro-permanent magnet based on coupling of multi-physics

The electro-permanent magnet (EPM) blank holder (EPMBH) technology has been combined with forming technology. The method commonly used in previous related studies was to simulate and analyze the magnetic field of the EPMBH device and obtain the magnetic attraction under corresponding conditions. During the forming process, a blank holder force with the same magnitude as the magnetic attraction was loaded, and then the temperature field of the EPMBH device was analyzed separately. Due to the lack of consideration of the interaction between various physical fields, there is a significant deviation between the simulation and experiment with this method. To improve the accuracy of analysis results, this article introduces an analysis method that considers the mutual influence of various factors and simulates the coupling of magnetic field, structural field, and temperature field in deep drawing, which is compared with the deep drawing experiment with EPMBH. There is no obvious temperature rise issue during the experiment, and constant blank holder force loading can be achieved with EPMBH. The results show that for 08-Al thin plate with an initial thickness of 0.8 mm and a diameter of 100 mm, the optimal magnetization current is 13 A and the drawn part can be obtained without wrinkling and fracture defects.

PURIFICATION OF LIQUIDS IMPURITIES BY ELECTROMAGNETIC INFLUENCE

The importance of liquid purification leads to a decrease in the concentration of pollutants mainly in the stream during its use. This paper analyzes the relevance of document verification in accordance with existing legislation. An analysis of actual physical and chemical methods of liquid purification was carried out. The creation of a working chamber for the grouping of impurities for liquid purification is described. The result was achieved by electromagnetic influence on charged impurities. The scientific news of the study of the creation of a paraboloid of rotation of impurities has been created. The principle of operation of the cleaning system is shown on the example of the grouping of oil and water impurities. Research results show the possibility of liquid purification by controlling the trajectory of impurities. The work uses the Dini equation (Italian: Ulisse Dini) to describe the mathematical model of the grouping of impurities. A model of the trajectory of impurities in the LabVIEW shell was created. The possibility of further purification of the liquid by the method of electromagnetic grouping and subsequent removal of impurities from the flow was verified. The study takes place in the installation of inductance coils on the outer surface of the impurity grouping chamber. The trajectory of the movement of impurities in the magnetic field is determined. The electromagnetic influence on the charged impurities changes their trajectory and causes the impurities to move along the Larmor radius. When the magnitude of the electromagnetic field increases, the speed of movement of the impurity increases, and the radius of motion of the impurity decreases. It has been proven that impurities with a lower density are better concentrated in the center of the RKG. The parameters of the coils for creating an electromagnetic field are selected. The model of the rotation of oil impurities in the driver is reproduced on the model. The change in the specific conductivity of the water medium with increasing magnetic field induction was verified. At the first stage, we offer the construction of a stand for further purification of liquid by the method of electromagnetic grouping of impurities. Practical recommendations are given for achieving the efficiency of the electromagnetic method of liquid purification and its reuse.

Magnetic-field induced asymmetric hydrogel fibers for tough actuators with programmable deformation

Ingenious design of soft actuators with high mechanical performance, rapid actuation, and programmable deformation is necessary for their practical applications in the fields of artificial muscles, smart textiles, and soft robotics. Here we used a facile magnetic-field induction strategy to fabricate programmable actuators composed of tough hydrogel fibers. The anisotropic hydrogel fibers that consisted of dual physically cross-linked networks showed high tensile strength (28.9 MPa), while the asymmetric distribution of magnetic nanoparticles in hydrogel networks endowed the actuators with rapid bending velocity (3.2°·min−1·mm−1) in response to solvents. The pick-and-place manipulation of objects from ethanol to water were demonstrated by using the soft grippers composed of asymmetric hydrogel fibers. Furthermore, smart curtains that were woven by hydrogel fibers automatically rolled up or spread out in response to the change of ambient humidity. This work proved that tough hydrogel fibers fabricated by our magnetic-field induction strategy provided more possibilities in the field of soft actuators.