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Flux density measurements provide valuable information on the state of electrical appliances, which can be utilised for improving the safety and the performance of the associated system. Exposure level testers with a B-field probe are widely used for flux density measurements but they can only perform a time-domain measurement and display it as output voltage related to flux density. In other words, they cannot output flux density directly, which brings many inconveniences. These drawbacks can be improved using data conversion coefficients. However, the test frequencies of mostexposure level testers aregreaterthan 1 Hz. They are unable tocalculate thedata conversion coefficients using a constant magnetic field. This paper proposes a method for data conversion of exposure level testers using alternating magnetic fields to measure flux density directly: the Aux density conversion model was established, the mathematical relationship between the mean value of the voltage signal output by the exposure level testers and its stable display value was deduced; and an experimental test of the conversion coefficients was carried out. The results show that the error between the value measured using the new technique and thedisplay value of the exposure level tester at different frequencies is small. This method can trace the flux density in both the time and frequency domains through software processing algorithms without changing the exposure level tester itself. By applying sinusoidal magnetic fields and using the conversion factor, then existing testers can be used to measure flux density directly. [ABSTRACT FROM AUTHOR]

The research involves examining the influence of partial solar eclipse on the strength of neutral hydrogen from the Sun. Baghdad University Radio Telescope (BURT) was used to monitor the partial solar eclipse on the 25th of October, 2022. Radio observations from the Sun were recorded from 11:30 AM to 03:36 PM. This means that the HI emission from the Sun was recorded before, during and after the event. It was noticed, that at the moment of maximum eclipse, ~ 46% of the Sun’s disk was covered by the Moon. For the purpose of this research, the solar radio wave intensity was monitored and the solar flux density was determined at different times, i.e. before, during and after the partial solar eclipse. The obtained results showed that both of the solar flux and power spectrum decrease with the progress of the eclipse until the moment of maximum eclipse, i.e. the moment at which the minimum values of solar flux density and antenna temperature were recorded (7 × 104 Jy and ~ 80 K). Then, at the last moments of the partial eclipse, it was noticed that both parameters started to increase again due to the decrease in the area of the Sun’s disk until both reached their normal values. In Conclusion, the partial solar eclipse affects the strength of neutral hydrogen from the Sun because the Moon blocks the neutral hydrogen from the Sun during the solar eclipse. [ABSTRACT FROM AUTHOR]

In this paper, we extract distinctive determination for quasi magnetic flux of the quasi binormal magnetic flows of magnetic quasi $ \mathbf {b}^{\mathbf {q}} $ b q -particle by considering directional frame in 3D ordinary space. Also, we construct some advanced optical qualifications for magnetic quasi Lorentz flux for magnetic quasi- $ \mathbf {b}^{\mathbf {q}} $ b q particle along with the quasi directional frame fields. Then, we calculate quasi magnetic Lorentz flux with directional-quasi magnetic fields. Besides, we obtain original simulations with regard to directional potentials for directional-quasi magnetic binormal flows with Heisenberg optical ferromagnetic model. Magnetic optical flux surfaces are demonstrated in a homogeneous optical flux surface by fractional numerical and applied developments. By using above models, we get new fractional model with q-homotopy analysis transform method (qHATM) and its illustrative presentation to consider magnetic optical flux surface. [ABSTRACT FROM AUTHOR]

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Brushless DC (BLDC) motors have gained popularity because of numerous advantages. This motor application is achievable Since permanent magnet (PM) technology has advanced. This motor has higher efficiency, reliability, and power density and requires less maintenance due to the absence of brushes. A higher torque-to-mass ratio and long life are two of this motor s most attractive characteristics, making it appropriate for highperformance applications. This study describes the hybrid methodology for analyzing a three-phase, four-pole, 1500 W, brushless DC (BLDC) motor with an inner rotor. This paper uses PI controllers and PWM in Matlab /Simulink and the chopped current control in Maxwell 2D. BLDC motor modeled by rotation machine export (RMxprt) analytical software and analyzed with a finite element method (FEM) Maxwell 2D software to calculate motor performance, such as torque, speed, and efficiency. The FEM results were verified by comparing them with the results taken from the Matlab/Simulink program and with the aid of the RMxprt software to supply some missing data. The results from Maxwell 2D and Matlab show good agreement. Despite lacking motor test data, this paper successfully applied a hybrid FEM-analytical approach to study a BLDC motor using three software packages RMxprt, Maxwell 2D, and Matlab/Simulink. The RMxprt program offers missing data like stator resistance, stator inductance, and torque constant. It is provided in the design sheet to help us with motor modeling. The successful adoption of the proposed hybrid FEM-analytical methodology will provide a good starting point for future BLDC motor research work. [ABSTRACT FROM AUTHOR]

The authors validate the use of magnetic hydrocycloning in extraction of weak magnetic-responsive slime particles from finely dispersed magnetic suspension. Efficiency of a lab-scale magnetic hydrocyclone with regular electromagnetic system of copper wires on the cone, without superconductive materials involved, in extraction of magnetite particles –20 m in size is described. The test results prove recoverability of hematite and other weakly magnetic minerals in magnetic hydrocycloning at the required flux density of 2–10 T created by a superconductive magnetic system under conditions of cooling at the liquid nitrogen temperature, which minimizes energy intake of magnetic separation. The use of the superconductive magnetic system and high-temperature materials on the hydrocyclone cone enables efficient extraction of weakly magnetic particles, for instance, red mud –10 m in size. [ABSTRACT FROM AUTHOR]

Computing the flux densities provided by solar concentrators or focusing heliostats can be done in two different ways: A grid ray-tracing (GRT) procedure that makes use of a large number of ray bundles, starting from the solar disk and finally impinging the focal plane of the concentrator. The method is reliable and accurate, but requires extensive computing times. Alternatively, the flux densities can be estimated by using convolution algorithms. This latter method requires much less computing time, but is known to be less accurate when the incidence angle of the sunrays on the reflector increases. The objective of this contribution is to define an algorithm based on convolution products and fast Fourier transforms having high accuracy. The results show that RMS error differences between both models are typically lower then 1%.

In this paper is presented a two-dimension analytical model for linear permanent magnet inner armature double-sided synchronous motors (LPMIADSSMs). The flux density in all areas of the proposed machine is calculated based on the sub-domain method. According to this method, the machine areas are divided into eleven sub-regions such as first external, first mover, first PM, first air gap, first winding, stator, second winding, second air gap, second PM, second external and second mover, which sign as FE, FR, FP, FAG, FW, S, SW, SAG, SP, SE and SR. To find the flux density equations, it is mandatory to solve the extracted Maxwell equations and apply the boundary conditions between each two sub-regions, which lead to find the unknown coefficients for flux density in each sub-region. In addition, the influences of magnetization patterns, i.e., parallel, ideal Hal Bach, 2-segment Halbach and bar magnet in the shifting direction of the flux distribution and armature reaction (AR), are investigated. To validate the obtained results, the proposed model results are compared with those obtained from finite element method (FEM) and Maxwell software. [ABSTRACT FROM AUTHOR]

As the capacity of the electrical system increases, so does the capacity of the electromagnetic contactor (MC). This increases the burden on the MC drive, which consumes unnecessary power in the system. MC is characterized by different initial starting-operating currents and holding currents to maintain contact. However, the operating voltage is constant regardless of the operating state. The initial starting current is considerably larger than that required to maintain contact. However, once the electromagnetic contactor is in the closed state, the current to maintain the contact is relatively small compared to the initial starting operating currents. Therefore, this study proposes two types of two-level excitation-current type MC drives that can reduce the drive power by employing features that have different conditions depending on the operating state of the MC. The overall drive power is reduced by applying different excitation currents based on the operating state. The controller and system proposed in this study were simulated using Powersim 9.1 (PSIM), and the feasibility was verified by manufacturing an analog-type driver using LM2576 and a digital-type driver using an MCU. The simulation and experimental results provide significant data for verifying the high performance and reliability of the proposed controller and system. [ABSTRACT FROM AUTHOR]

Brushless DC (BLDC) motors and derives have gained popularity because of numerous advantages. This motor application is achievable since permanent magnet (PM) technology has advanced. It has higher efficiency, reliability, and power with less maintenance due to the absence of brushes. A higher torque-to-mass ratio and long life are two of the most attractive characteristics making it appropriate for high-performance applications. This study describes the hybrid methodology for analyzing a three-phase, four-pole, 1500 W, brushless DC (BLDC) motor with an inner rotor. PI controllers and PWM in Matlab /Simulink, and the chopped current control in Maxwell 2d ae used. BLDC motor modeled by rotation machine export (RMxprt) analytical software and analyzed with a finite element method (FEM) Maxwell 2D software to calculate motor performance, such as torque, speed, and efficiency. The FEM results were verified by comparing them with the results taken from the Matlab/Simulink program and with the aid of the RMxprt software to supply some missing data. The motor torque and efficiency results from Maxwell 2D and Matlab show good agreement. A hybrid FEM-analytical approach is successfully applied to study a BLDC motor using three software packages RMxprt, Maxwell 2D, and Matlab/Simulink despite the lack of motor test data. The RMxprt program offers missing data like stator resistance, stator inductance, and torque constant. It is provided in the design sheet to help us with motor modeling. The successful adoption of the proposed hybrid FEM-analytical methodology will provide a good starting point for future BLDC motor research work

Inrush current is high-magnitude current drawn by power transformers upon energization. The severity of inrush current depends on factors such as the transformer’s residual flux and the voltage phase angle at the energization instant. This paper proposes a flux matching method for the energization of V/V traction transformers to mitigate inrush current. This is achieved by adjusting the residual flux of the core to an appropriate reference value and then obtaining the proper energization instant. To this end, the method only requires knowledge of nominal voltage and excitation current, eliminating the need to acquire transformer’s parameters/design information. The railway power conditioner, typically present at the low voltage side of the V/V transformer, is used as a current source to inject sinusoidal current into the transformer windings before its energization. The reference residual flux is calculated based on the circuit breaker operating characteristics. The energization instant is determined such that the adjusted flux density matches the steady-state flux expected with respect to the applied voltage. The proposed method is validated by conducting over 14,000 simulations under different conditions using PSCAD/EMTDC. The method is also implemented and successfully tested on a laboratory-scale test rig, which verifies its effectiveness in more realistic conditions.

This research paper investigates the influence of shielding and core materials on the performance of dynamic wireless charging (DWC) systems. A 2D model for finite element analysis (FEA) is developed to assess the flux density of coil structures within the DWC system, considering various combinations of shielding and core materials. Specifically, the study focuses on employing an aluminum shield and a ferrite core in the DWC system. Through the finite element analysis, the mutual inductance and efficiency of the DWC system are evaluated, with the simulations accounting for the presence of the aluminum shield and ferrite core to discern their impact on system performance. The FEA analysis is instrumental in determining the mutual inductance and power transferred under different scenarios, thus enabling technical evaluation. The research findings reveal the ramifications of using specific shielding and core materials on the performance of the DWC system, offering insights into the finest configurations for various applications. The novelty of this study lies in leveraging FEA analysis to comprehensively evaluate the influence of shielding and core materials on DWC system performance. As a result, this work presents valuable guidance for designing and configuring DWC systems tailored to specific applications. The insights provided pave the way for an enhanced understanding of DWC systems, ultimately fostering advancements in wireless charging technology.

Evaporating a liquid sessile drop deposited on a horizontal surface is an important object of applications (printing technologies, electronics, sensorics, medical diagnostics, hydrophobic coatings, etc.) and theoretical investigations (microfluidics, self-assembly of nanoparticles, crystallization of solutes, etc.). The arsenal of formulas for calculating the slow evaporation of an axisymmetric drop of capillary dimensions deposited on a flat solid surface is reviewed. Characteristics such as vapor density, evaporation flux density, and total evaporation rate are considered. Exact solutions obtained in the framework of the Maxwellian model, in which the evaporation process of the drop is limited by vapor diffusion from the drop surface to the surrounding air, are presented. The summary covers both well-known results obtained during the last decades and new results published by us in the last few years, but practically unknown to the wider scientific community. The newest formulas, not yet published in refereed publications, concerning exact solutions for a number of specific contact angles are also presented. In addition, new approximate solutions are presented (total evaporation rate and mass loss per unit surface area per unit time in the whole range of contact angles θ ∈ [ 0 ,   π) , drop lifetime in constant contact radius evaporation regime and constant contact angle mode), which can be used in modeling without requiring significant computational resources. [ABSTRACT FROM AUTHOR]

In this paper, the diagnosis of faults in squirrel cage asynchronous motor and experimental analysis process are presented. Currently there are several simulation tools, that lets users analyze and interpret the behavior of their devices. Based on this, there is a lot of researches that is working on developing models, to detect and classify 3-phase asynchronous motor faults, significantly in the early stages. This work proposed design and experimental analysis established in Comsol Multiphysics 6.0, which implements finite element analysis software (FEM) for detecting and diagnosing broken bar rotors of this types motors and its practical application. In this case, the post processor of the COMSOL-Multiphysics makes it possible to visualize in 2D the various magnetic and mechanical quantities. Through the curves of the magnetic flux density and analysis distribution of the field with magnetic induction lines, we can draw some conclusions, where we proposed an strategy, for detecting and diagnosing faults consistent with the structure of the software. [ABSTRACT FROM AUTHOR]

Magnetic fields in transformer cores are typically assumed to be one-dimensional fields, thus allowing magnetization processes to be regarded as axial magnetization. However, in the core corners or T-joint points of medium- and high-power rating transformers, the magnetic lines have different directions with respect to the rolling direction. This paper describes a method that allows changes in the flux density of transformer steel sheets to be calculated for any magnetization direction. These changes are assumed to depend only on certain limiting hysteresis loops assigned separately to the rolling and transverse directions of a tested transformer sheet, where these loops depend on the magnetization direction on the sheet plane. The selection of coefficients that define the limiting hysteresis loops for several magnetization directions is described, and the condition for the flux density saturation is considered. The resultant flux density in a specified magnetization direction is the geometric sum of the corresponding flux densities assigned to both the rolling and transverse directions. The limiting and partial hysteresis loops determined based on the proposed method for several magnetization directions are compared with analogous measured loops. Additionally, a comparison of the calculated hysteresis loops with loops showing changes in the resultant flux density for several magnetization direction is presented. [ABSTRACT FROM AUTHOR]

This article focuses on the optimization of process parameters such as core area, core material and voltage for the design of power transformer. It employs Taguchi orthogonal array technique for designing the experiments and its analysis. Utility transformers are usually specified with the losses associated at design stage. The area of the core cross-section applied voltage, as well as the core material all has impact core loss deterioration. The impact of such variables influencing core loss is investigated by executing the model. A small proportion of core as well as the coil assembly experiments is simulated using the Taguchi approach with the orthogonal array. In this study, the core as well as the coil assembly of an 8MVA, 33/11KV, 3 Phase Transformer is modelled in ANSYS MAXWELL software. MINITAB software is used to assess the program's anticipated core loss in order to discover the optimal arrangement for three control variables. [ABSTRACT FROM AUTHOR]

The electromagnetic background was measured in the living quarters of the Vostok Station located on the Antarctic plateau distant from the potential sources of technogenic electromagnetic fields. The level of E-radiation in the range from 0.8 to 8 GHz was determined using a MERA integral dosimeter. Based on the results of long-term continuous (one to 4 months) measurements, the mean flux density was equal to 1.5 ± 0.8 nWt/cm, which is nearly 7000 times lower than the admissible level for population adopted in Russia. The Antarctic Vostok Station can be considered as a plausible location for biomedical investigations into the effects of low-frequency electromagnetic radiation. [ABSTRACT FROM AUTHOR]

Red lettuce (Lactuca sativa L.) is widely consumed for its health benefits. With the a growing global population and limited land resources, there is a need to increase the nutritional content and bioactive compounds of vegetables or fruits. This research aims to increase the growth, productivity, and the content of anthocyanin, vitamin C and flavonoids in red lettuce leaves through exposure to magnetic fields during seeding. The research utilized red lettuce seeds as the research sample. Exposure was carried out using an alternating magnetic field (MF) with an effective magnetic flux density (MFD) of 0.4 mT, a frequency range of 25-125 Hz, and a dailyexposure time of 15 minutes. The treatment of each sample group was repeated for five days. The results showed that exposure to a MF with a frequency of 75 Hz resulted in optimum growth and weight, an increase of 65.15% and 60.18%, respectively. The optimum anthocyanin, vitamin C, and flavonoid content were obtained at an exposure to a frequency of 100 Hz, an increase of 22.52%, 40.70%, and 32.50%, respectively. Exposure to seeds uses an alternating MF; frequency is an important parameter for producing optimum enhancement. [ABSTRACT FROM AUTHOR]

This article focuses on the optimization of process parameters such as core area, core material and voltage for the design of power transformer. It employs Taguchi orthogonal array technique for designing the experiments and its analysis. Utility transformers are usually specified with the losses associated at design stage. The area of the core cross-section applied voltage, as well as the core material all has impact core loss deterioration. The impact of such variables influencing core loss is investigated by executing the model. A small proportion of core as well as the coil assembly experiments is simulated using the Taguchi approach with the orthogonal array. In this study, the core as well as the coil assembly of an 8MVA, 33/11KV, 3 Phase Transformer is modelled in ANSYS MAXWELL software. MINITAB software is used to assess the program's anticipated core loss in order to discover the optimal arrangement for three control variables.

Switched reluctance motor has the advantages of the high efficiency, low cost, strong fault tolerance, and high reliability. A 5.5 kW, 12/8 pole switched reluctance motor is designed. The novel transient electromagnetic field-control circuit coupled calculation method of switched reluctance motor is proposed. The influence of different PWM switching angles, chopping current thresholds, and hysteresis current widths on flux density and loss of stator core in the switched reluctance motor is studied in detailed by this novel method. Controller harmonics are considered during this calculation. The change of the flux density and loss of stator core in the switched reluctance motor is compared and analyzed under the different controller parameters. The reliability of the calculation method and accuracy of the calculation results are verified by experimental values.

Subdomain models have been widely used to quickly model the fields and the torque of surface-mounted permanent-magnet machines (SMPMMs). Nevertheless, when magnetic saturation occurs, those models which assume the permeability of the iron parts to be infinite tend to be inaccurate. More recently, two types of models have been developed that take the finite magnetic permeability of the machines into account, but a comparison of those models is still lacking. This article compares two finite-permeability subdomain models of SMPMMs. In the stator teeth and slots of the first model, boundary conditions are used in both radial and tangential directions. In the second model, the permeability change as a function of the angle in the stator slot and teeth is modeled using the Fourier series and the Cauchy product to solve Maxwell’s equations. In this study, the calculation of two different SMPMMs shows that both models can handle machines with low and high numbers of teeth. This study shows that the error of the first model has a low sensitivity to iron permeability and parameter changes, while the accuracy of the second model heavily depends on the iron permeability and parameters. For a higher iron permeability, the second model is less accurate. Both models can achieve high prediction accuracy at a faster calculation speed than the finite element model. The first model needs only a few harmonics to have high accuracy.

An analytical method was proposed for obtaining the magnetic field distribution for surface-mounted permanent magnet machines with the structure of unequal magnetic poles. Firstly, the Laplace equation and Poisson equation were solved using the method of the separation of variables, and then the mathematical model of the motor structure with unequal magnetic poles was obtained. Secondly, according to the design parameters of the two types of prototypes motors, the flux density in the air gap region of the two types of prototypes motors was calculated, respectively. Thirdly, by comparing the results calculated using the analytical method with the results obtained using the finite element method, the analytical method proposed in this paper was proven to be effective. Moreover, the armature reaction field and the effect of the stator slotting were considered in the mathematical model as well. Overall, the analytical method presented in this paper provides a theoretical basis for the analytical calculation of motors with the structure of unequal magnetic poles. [ABSTRACT FROM AUTHOR]

Evaporating a liquid sessile drop deposited on a horizontal surface is an important object of applications (printing technologies, electronics, sensorics, medical diagnostics, hydrophobic coatings, etc.) and theoretical investigations (microfluidics, self-assembly of nanoparticles, crystallization of solutes, etc.). The arsenal of formulas for calculating the slow evaporation of an axisymmetric drop of capillary dimensions deposited on a flat solid surface is reviewed. Characteristics such as vapor density, evaporation flux density, and total evaporation rate are considered. Exact solutions obtained in the framework of the Maxwellian model, in which the evaporation process of the drop is limited by vapor diffusion from the drop surface to the surrounding air, are presented. The summary covers both well-known results obtained during the last decades and new results published by us in the last few years, but practically unknown to the wider scientific community. The newest formulas, not yet published in refereed publications, concerning exact solutions for a number of specific contact angles are also presented. In addition, new approximate solutions are presented (total evaporation rate and mass loss per unit surface area per unit time in the whole range of contact angles θ∈[0, π), drop lifetime in constant contact radius evaporation regime and constant contact angle mode), which can be used in modeling without requiring significant computational resources.

The very close d-axis and q-axis inductances of the flux-switching permanent magnet (FSPM) machine make it even similar to a surface-mounted permanent magnet (SPM) machine, especially those with fractional slot and concentrated windings (FSCW), which is usually applied in a light-power situation where small size and high power density are desired. Based on finite element analysis (FEA), the FSPM machine with 6-slots/5-poles (5 pole pairs) is designed for light servo applications and further compared to an SPM machine with 9-slots/8-poles (4 pole pairs), covering electromagnetic, thermal, and mechanical behaviors. The rotor skewing of the FSPM machine is also studied. Finally, the prototypes of the FSPM and SPM machines are manufactured and experimental measurements are carried out to validate the FEA results. [ABSTRACT FROM AUTHOR]

The search for pulsars outside the plane of the galaxy in an area of 300 sq. deg. was carried out with the LPA LPI antenna at 111 MHz, with a sensitivity 5 to 10 times better than that of previous surveys. The search was performed in the summed power spectra. With an accumulation time equivalent to 100 hours of continuous observations for each point of the area, 5 known pulsars were found with a signal-to-noise ratio (S/N) from 20 to 1300 in the first harmonic of the spectrum. Average profiles are obtained for the detected pulsars. Estimates are given for the peak and integrated flux densities of the found pulsars for individual sessions and for power spectra summed over 5.5 years, using the developed method based on measurements of harmonic heights in the power spectrum. No new pulsars were found in the area. Apparently, when searching for pulsars in the area, we approached the lower limit of the luminosity of second pulsars. The survey completeness is at the level of 0.5 mJy. [ABSTRACT FROM AUTHOR]

Kapton film is a polymeric material widely used on low-Earth-orbit (LEO) spacecraft surfaces. In the LEO environment, atomic oxygen (AO) is spaceflight materials' most destructive environmental factor. The erosion mechanism of AO on Kapton films has long been an important issue, where the parameter dependence of the AO effect has received increasing attention. Studies of AO energy and cumulative flux have been extensively carried out, while the influence mechanism of the incidence angle and flux density is not fully understood. The AO incidence angle and flux density in space are diverse, which may cause different damage effects on aerospace materials. In this paper, the dependence of the incidence angle and flux density in the damaging effect of AO on Kapton films was investigated using ground-based AO test technology and the reactive molecular dynamics (ReaxFF MD) simulation technique. Firstly, the ground-based experiment obtained the mass loss data of Kapton films under the action of AO with a variable incidence angle and flux density. Then, the mass loss, temperature rise, product, and erosion yield of Kapton during AO impact with different incidence angles and dose rates were calculated using the ReaxFF MD method. The influences of the incidence angle and flux density on the damage mechanism of the AO effect were discussed by comparing the simulation and test results. The results show that the AO effect in the lower incidence angle range (0–60°) is independent of the incidence angle and depends only on the amount of impacted atomic oxygen. AO in the higher incidence angle range (60–90°) has a surface stripping effect, which causes more significant mass loss and a temperature rise while stripping raised macromolecules from rough surfaces, and the erosion effect increases with the increasing incidence angle and amount of impacted atomic oxygen. There is a critical value for the influence of flux density on the AO effect. Above this critical value, AO has a reduced erosive capacity due to a lower chance of participating in the reaction. The amount of each main product from the AO effect varies with the incidence angle and flux density. Nonetheless, the total content of the main products is essentially constant, around 70%. This work will contribute to our understanding of the incidence angle and flux density dependence of the AO effect and provide valuable information for the development of standards for ground simulation tests. [ABSTRACT FROM AUTHOR]

Nowadays, energy shortages and environmental pollution have received a lot of attention, which makes the electrification of transportation systems an inevitable trend. As the core part of an electrical driving system, the electrical machine faces the extreme challenge of keeping high power density and high efficiency output under complex workin g conditions. The development and research of new soft magnetic materials has an important impact to solve the current bottleneck problems of electrical machines. In this paper, the variation trend of magnetic properties of ultra-thin grain-oriented silicon steel electrical steel (GOES) under thermal-mechanical-electric-magnetic fields is studied, and the possibility of its application in motors is explored. The magnetic properties of grain-oriented silicon steel samples under different conditions were measured by the Epstein frame method and self-built multi-physical field device. It is verified that the magnetic properties of grain-oriented silicon steel selected within 30° magnetization deviation angle are better than non-grain-oriented silicon steel. The magnetic properties of the same ultra-thin grain-oriented silicon steel as ordinary non-oriented silicon steel deteriorate with the increase in frequency. Different from conventional non-grain-oriented silicon steel, its magnetic properties will deteriorate with the increase in temperature. Under the stress of 30 Mpa, the magnetic properties of the grain-oriented silicon steel are the best; under the coupling of multiple physical fields, the change trend of magnetic properties of grain-oriented silicon steel is similar to that of single physical field, but the specific quantitative values are different. Furthermore, the application of grain-oriented silicon steel in interior permanent magnet synchronous motor (IPM) for electric vehicles is explored. Through a precise oriented silicon steel motor model, it is proved that the magnetic flux density of stator teeth increases by 2.2%, the electromagnetic torque of motor increases by 2.18%, and the peak efficiency increases by 1% after using grain-oriented silicon steel. In this paper, through the investigation of the characteristics of grain-oriented silicon steel, it is preliminarily verified that grain-oriented silicon steel has a great application prospect in the drive motor (IPM) of electric vehicles, and it is an effective means to break the bottleneck of current motor design. [ABSTRACT FROM AUTHOR]

The article presents an analytical method for optimizing the geometry of the magnetic core of a three-phase compensation choke. The method describes the process of identification the fringing magnetic fields and the corresponding magnetic reluctances of the magnetic core, the flux density calculation even in the case of the core supersaturation and the total losses estimation. It shows finding the trade-off between the size/weight of the inductor and the magnetic core with respect to the overall losses and demonstrates their minimization. The mathematical model for the flux’s identification is based on a standard iterative calculation using the analogy to electrical circuits but includes a new approach to the calculation of fringing magnetic fields caused by the air gapped magnetic core. The presented method is verified by the finite element method (FEM) using the engineering calculation software ANSYS.

The composition of GET 39-2021 State primary standard of units of volumetric activity of radioactive aerosols, radon, thoron, and radon flux density is presented. Methods for reproducing and transferring the units of volumetric activity of radioactive aerosols, radon, thoron, and radon flux density are described. Possible sources of error are identified, and their quantitative assessment is performed. The metrological characteristics of GET 39-2021 are provided. GET 39-2021 ensures the uniformity of measurements of the volumetric activity of radioactive aerosols, radon, thoron, and radon flux density in various fields, including the nuclear industry, at enterprises for the extraction and processing of nuclear raw materials, etc. In the nuclear industry, GET 39-2021 can be used to ensure the radiation protection of personnel and the environment during the construction and commissioning of new-generation nuclear reactors. [ABSTRACT FROM AUTHOR]

This paper describes a 3D finite element (FE) based method to calculate the proximity losses for magnetic components in power conversion system. The proximity loss is the main concern of copper loss which causes ac losses in the winding. The FE model is built based on the definitions of the geometries, meshes, materials, electric circuits, boundary conditions, load conditions, as well as the characteristics of the wire. The total proximity loss is the sum of the power losses of each element calculated with the power loss density function using the obtained nodal flux densities via finite element analysis (FEA) at the given load condition. Owing to a detailed model with all the geometric parameters and thus the flux leakage and end-winding effects can be considered, this FEA approach can predict the flux density more accurately. In addition, non-sinusoidal current is analyzed to calculate the actual power loss in current distortion condition. Experimental tests have been implemented to validate the method. The approach is capable of calculating the energy consumption in power converter for efficiency approvement and energy management.

The paper presents the results of the analysis of long-term series of monitoring data on the radon flux density. They were produced using a accumulation chamber of our own design, which allows, in terms of the readings of alpha radiation counters, to obtain the values of the radon flux density. The main results and the most illustrative examples of the behavior of the investigated characteristic of radon are present in the work. As a result, conclusions were drawn about the features of radon release rate from the soil into the surface atmosphere at different time scales and under different meteorological conditions, which can be used in the future to monitor the radon flux density using ionizing radiation detectors, and is also fundamental for the development new models.

In this paper, we state the problem of constructing evolution equations describing the dynamics of condensed matter with an internal structure. Within the framework of this statement, we describe the class of evolution equations for vector and pseudovector fields on ℝ3 with an infinitesimal shift defined by a second-order, divergent-type differential operator, which is invariant under translations of ℝ3 and time translations and is transformed covariantly under rotations of ℝ3. The case of equations of this class with preserved solenoidality and unimodality of the field is studied separately. A general formula for all operators corresponding to these equations is established. [ABSTRACT FROM AUTHOR]

This paper proposes modeling and optimization of a new Reluctance Axial Flux Magnetic Gear (RAMG) that enjoys a stationary outer rotor and lower permanent magnet usage. Due to the insignificant use of the PMs, this structure has a higher economic interest, greater reliability, and more simple and robust structure than its conventional ones. Gear ratio and operating principles are extracted and verified using 3D Finite Element Method (FEM) simulations. Finally, parametric optimization is done based on effective dimensions in design procedure with maximum torque density objective function. The magnetic flux distributions of optimized RAMG are calculated using 3D FEM and static and dynamic magnetic torques are derived correspondingly. [ABSTRACT FROM AUTHOR]

This work reports radon-thoron monitoring at two depths (60 and 90 cm) and at 82 sites around Jawalamukhi thrust of NW Himalaya, India using Solid State Nuclear Track Detectors (SSNTDs). Further, radium contents of soil samples have been measured using NaI(Tl) crystal detectors and the exhalation rates have been measured using SMART Rn Duo monitor. The average radon-thoron concentrations at two different depths are found to be 3043 ± 691 Bq m−3, 4969 ± 561 Bq m−3 & 448 ± 416 Bq m−3, 773 ± 117 Bq m−3. Average value of area exhalation rate found to be 299.9 × 10−3 Bq m−2 h−1 with radium contents of value 51.04 Bq kg−1. The convective velocity of radon-thoron along with their flux densities has also been calculated. The average magnitudes of flux densities for radon-thoron found to be 44.96 × 10−2 Bq m−2 s−1 and 15.57 × 10−2 Bq m−2 s−1 whereas the convective velocities calculated to 8.38 × 10−6 m s−1 and 25.69 × 10−3 m s−1. The recorded values of thoron are lower than the recorded radon values. Moreover, the value of radon and thoron is higher at depth 90 cm than at depth 60 cm. The anomalous radon-thoron concentrations have been observed along the Jawalamukhi thrust and at some other sites suggesting secondary porosity or presence of local fault/lineament. A good correlation between area exhalation rates and radium contents, as well as between mass exhalation rates and radium has been observed. However weak correlation between porosity and area exhalation rates has been observed in this region. [ABSTRACT FROM AUTHOR]

In this paper, an analytical method (AM) based on the air-gap magnetomotive force (MMF) permeance model is proposed to predict the nonlinear instantaneous torque of switched reluctance machines (SRMs). The analytical expression of the air-gap MMF is first obtained from the winding function and current profile, while the air-gap magnetic permeance considering the double-sided slotting effects is also derived. Then, the nonsaturated field distribution along the air-gap circumference is presented based on which the instantaneous torque can be calculated from the Lorentz force law. Furthermore, the model is enhanced with a saturation distribution factor to include the nonlinear characteristics. The proposed method is free from preliminary data or empirical coefficient and benefits from the simplified model and solution. The AM will be validated by the two-dimensional finite-element method based on four SRMs with different structures. Moreover, an SRM prototype is manufactured for experimental verification. [ABSTRACT FROM AUTHOR]

This paper proposes an analytical no‐load magnetic field model taking account of the curvature coefficient to compute the no‐load magnetic field of parallel direct‐driven conjoined permanent magnet synchronous motor (PDC‐PMSM). The shortcomings of the 3‐D finite element method are avoided, such as the time‐consuming and sensitive to finite element meshes. As well as, putting forward the design method of the motor. A 2‐D subdomain model of PDC‐PMSM can be obtained by segment 3‐D model at the average radius, which is quasi to linear permanent magnet synchronous motor. Based on Maxwell's equations, the Poisson's equations in the permanent magnet (PM) subdomain and the Laplace's equations in the subdomain between air gap and PM are calculated under no‐load condition. The radial and tangential flux density of each subdomain are obtained by the Fourier's series, hyperbolic functions, separation of variables, and the boundary condition. Better yet, the curvature coefficient is introduced to reduce the error between the analytical magnetic field in the planar model and the tubular model. The analytical no‐load magnetic field model is established more accurately. The expression of curvature coefficient and back‐electromotive force are derived. One prototype is manufactured for simulation and experimental study. The accuracy and feasibility of the proposed model are verified by the prototype test. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Performance prediction of induction machines (IMs) is highly dependent on the accuracy of the material characteristics and geometry of the machine during the modeling stage. To reduce the complexity of an IM model, normally the slotting effects are neglected. Likewise, the permeability of the stator and rotor cores are assumed to be infinite leading to an ideal set of partial differential equations (PDEs) for homogenous and isotropic materials. In this paper, the permeability of the stator and rotor cores are assumed not to be infinite and the slotting effects are taken into consideration to propose a more accurate and realistic model of an IM to reduce the discrepancies between the performance expectations and actual results. Fourier-based (FB) magnetic field approach is used to fulfill this aim via anisotropic layer theory (ALT) enabling the proposed model to include distortion of magnetic flux in the slotted regions. Air-gap flux density, core losses, efficiency and torque of an IM are predicted via the FB model and are validated through the finite element analysis (FEA) and experimental studies. [ABSTRACT FROM AUTHOR]

This paper presents a fast analytical model for estimating the components of the PM flux density distribution in the air-gap for a number of interior permanent magnet synchronous machines (IPMSMs). Deriving the two-dimensional (2-D) analytical model for IPMSMs is more challenging compared to that of surface-mounted permanent magnet synchronous machines (SPMSMs) due to the inconsistent geometry of the rotor in polar coordinates. IPMSMs are usually modeled by using 0-D or 1-D methods such as the magnetic equivalent circuit (MEC); however, the MEC method is unable to take into account the tangential component of the magnetic flux density vector. In this paper, a 2-D analytical no-load electromagnetic model for five rotor topologies of IPMSMs is proposed. The effects of the stator slots on the radial component of the PM flux density distribution in the air-gap are then included by defining an air-gap function. The effects of the stator slots on the tangential components of the PM flux density distribution in the air-gap are also considered by injecting virtual surface currents (VSCs) or virtual permanent magnets (VPMs). For verification purposes, the analytical results are compared with those of the finite element method (FEM) and the experimental results of one of the cases. [ABSTRACT FROM AUTHOR]