Magnetic Poles Research Articles

Performance evaluation of ALIP applying fully enclosed slot

ABSTRACT In nuclear energy systems, annular linear induction pump (ALIP) is regarded as an ideal device for transporting liquid metal. Developed pressure and efficiency are crucial indicators for evaluating performance of an ALIP, and enhancing these fac- tors is of utmost importance. This paper presents a 2D axisymmetric finite element method (FEM) model for efficiently predicting the performance of ALIP and a 3D FEM model to explore the implementation of a fully enclosed slot structure. The accuracy of the proposed models is validated by comparing the results with experimental data, complemented by empirical formulas in the post-processing phase. The continuous and discontinuous conditions of the pole pieces are analyzed using the 3D FEM, demonstrating that the fully enclosed slot structure can significantly enhance both developed pressure and efficiency, thereby improving the overall performance of the ALIP.

WISE J152614.95-111326.4, an Unusual Variable Star

ABSTRACT New time series photometry of WISE J152614.95-111326.4, an eclipsing binary candidate, has been obtained. Full cycles of variation were covered in five filters, ranging from B to z. Archival time series photometry is also available from several sources. The phased light curve shape changes from a double wave form in the red, to a single wave at shorter wavelengths. Analysis of the spectral energy distribution and SALT spectra shows the presence of a cool (∼ 7250−7900 K) white dwarf and an M6 star. The light curves can be explained by a hot spot on the opposing hemisphere of the white dwarf. The star may be in a pre-cataclysmic variable phase with a very low rate of mass flow from the red dwarf to the white dwarf, such that no flickering is evident. Evidence in favour of this hypothesis is that the period of the system (2.25 h) is in the cataclysmic variable period gap. It is speculated that a weak magnetic field associated with the white dwarf funnels accreted material onto a magnetic pole. Amplitudes of the W1 and W2 WISE light curves are anomalously large. The possibility is discussed that variability in this spectral region is primarily driven by electron cyclotron radiation.

Design and Analysis of Special-Shaped Pole Piece PMSM With Low Vibration and High Overload Capacity

Design and Analysis of Special-Shaped Pole Piece PMSM With Low Vibration and High Overload Capacity

Monte Carlo modeling of the origin of contaminant electrons on a 0.5T bi-planar Linac-MR.

In the last decade, hybrid linear accelerator magnetic resonance imaging (Linac-MR) devices have evolved into FDA-cleared clinical tools, facilitating magnetic resonance guided radiotherapy (MRgRT). The addition of a magnetic field to radiation therapy has previously demonstrated dosimetric and electron effects regardless of magnetic field orientation. This study uses Monte Carlo simulations to investigate the importance and efficacy of the magnetic field design in mitigating surface dose enhancement in the Aurora-RT, focusing specifically on contaminant electrons, their origin, and energy spectrum. The Aurora-RT 0.5 T Biplanar Linac-MR device was modeled using the BEAMnrc package using the updated EM macros, a magnetic field map generated from Opera 3D. Simulation generated phasespace data at the distal side of the first magnetic pole plate (89cm) and at machine isocenter (120cm) were analyzed with respect to electron energy spectra and electron creation origins, both with and without the static magnetic field. The presence of the main magnetic field was verified to affect the origin and distribution of contaminant electrons, removing them from the air column up to 60cm from the target, and focusing them along the CAX within the region below. Analysis of the remaining electron energy fluence reveals the net removal of electrons with energies>2 MeV and generation of electrons with energies<2 MeV in the presence of the static magnetic field as compared to no magnetic field. Moreover, in the presence of the magnetic field the integral energy contained in the contaminant electrons increases from 89cm to isocenter but is still 15% less overall than the integral energy contained in contaminant electrons without the magnetic field. This study provides an analysis of contaminant electrons in the Aurora-RT 0.5 T Linac-MR, emphasizing the role of magnetic field design in successfully minimizing electron contaminants.

Performing Magnetic Boundary Modulation to Broaden the Operational Wind Speed Range of a Piezoelectric Cantilever-Type Wind Energy Harvester

Small piezoelectric wind-induced vibration energy harvesting systems have been widely studied to provide long-term sustainable green energy for a large number of wireless sensor network nodes. Piezoelectric materials are commonly utilized as transducers because of their ability to produce high output power density and their simple structure, but they are prone to material fracture under large deformation conditions. This paper proposes a magnetic boundary modulated stepped beam wind energy harvesting system. On the one hand, the design incorporates a composite stepped beam with both high- and low-stiffness components, allowing for efficient vibration and electrical energy output at low wind speeds. On the other hand, a magnetic boundary constraint mechanism is constructed to prevent the piezoelectric sheet from breaking due to excessive deformation. Experiments have confirmed that the effective operational wind speed range of the harvester with magnetic boundary constraints is doubled compared to that of the harvester without magnetic boundary constraints. Furthermore, by adjusting the magnetic pole spacing of the boundary, the harvesting system can generate sufficiently high output power under high-wind-speed conditions without damaging the piezoelectric sheet.

Research on Performance of Interior Permanent Magnet Synchronous Motor with Fractional Slot Concentrated Winding for Electric Vehicles Applications

The fractional-slot, concentrated-winding, interior permanent magnet synchronous motor (FSCW IPMSM) has advantages, such as reducing motor copper consumption, improving flux-weakening capability, and motor fault tolerance, and has certain development potential in application fields such as electric vehicles. However, fractional-slot concentrated-winding motors often contain rich harmonic components due to their winding characteristics, leading to increased motor losses and back electromotive force harmonics, thereby affecting the efficiency and constant power speed regulation range of the motor. Based on this, this article first uses the winding function method to explore the inductance and saliency ratio of the interior permanent magnet synchronous motor with different slot pole combinations in the fractional-slot concentrated- winding of electric vehicles. Secondly, this article will establish a 2D finite element parameterized model to analyze and compare the performance of fractional-slot concentrated-winding motors with different slot pole combinations, including air gap magnetic density, back electromotive force distortion rate, overload multiple, and torque. The structural parameters of the motor were optimized with the objective of minimizing the torque ripple under the constraint of minimizing the average torque reduction. The motor slot width, permanent magnet angle, and permanent magnet pole arc angle were analyzed and optimized. The simulation results showed that 12 slots and 8 poles were the optimal design schemes, providing a theoretical basis for the selection of slot pole coordination in the fractional-slot concentrated-winding interior permanent magnet synchronous motor for electric vehicles.

Improving magnetic properties of FeCrCo films by facilitating the internal α-γ phase transition through Pt diffusion

FeCrCo magnetic films are suitable candidates for use as magnetic code disk materials in high-accuracy magnetic encoders. The performance and material uniformity of FeCrCo films are crucial for high-accuracy servo control of the encoder. However, enhancing coercivity and maintaining material uniformity while ensuring sufficient remanence in FeCrCo films pose challenges. Herein, Pt (t nm)/FeCrCo (100 nm) films were prepared via magnetron sputtering and subsequent vacuum annealing. The remanence of the FeCrCo (100 nm) monolayer film is 520 emu/cm3, with a coercivity of only 380 Oe. However, after using Pt as the buffer layer, the remanence of Pt (1 nm)/FeCrCo (100 nm) and Pt (2 nm)/FeCrCo (100 nm) films is 320 emu/cm3 and 250 emu/cm3 respectively, while the coercivity increases to 520 Oe and 625 Oe respectively, representing improvements of 37 % and 65 %. This significant increase in coercivity is achieved with the remanence still meeting the performance requirements of the magnetic code disk. High-resolution transmission electron microscopy (HRTEM) analysis reveals that diffused Pt atoms can facilitate the formation of a small amount of non-magnetic γ-FeCrCo phase, which has a pinning effect on magnetic domain walls, thus significantly increasing the coercivity of the FeCrCo film. Moreover, since the γ-FeCrCo phase and the α-FeCrCo phase have similar crystal lattices, material uniformity can be maintained, which is beneficial for ensuring the uniformity of output signals of the code disk with small magnetic pole pitches.

Aeromagnetic Data Analysis for Sustainable Structural Mapping of the Missiakat Al Jukh Area in the Central Eastern Desert: Enhancing Resource Exploration with Minimal Environmental Impact

This study integrates aeromagnetic data with geological information to develop a consistent interpretation of both shallow and deep structural frameworks at various depths in the Missiakat Al Jukh area, located in the Central Eastern Desert, Egypt. The research begins by processing reduced-to-the-north magnetic pole (RTP) anomalies, using Fast Fourier Transformation (FFT) techniques to distinguish between local residual structures and broader regional features. This multi-scale approach enables a more detailed understanding of the geological complexity in the region, revealing its subsurface structures. Advanced geophysical methods such as upward continuation, Euler deconvolution, source parameter imaging (SPI), and global particle swarm optimization (GPSO) were applied to further refine the determination of structural depths, offering critical insights into the distribution and orientation of geological features at varying depths. The study reveals dominant structural orientations aligned in the NNW-SSE, ENE-WSW, north–south, and east–west directions, reflecting the region’s complex tectonic history. This research is of great importance in terms of sustainability. By delivering detailed subsurface maps and providing more accurate depth estimates of basement rocks (between 0.6 and 1.3 km), it contributes to sustainable resource exploration in the region. A better understanding of the geological structure helps minimize the environmental impact of exploration by reducing unnecessary drilling and concentrating efforts on areas with higher potential. Additionally, the use of non-invasive geophysical techniques supports the transition toward more environmentally conscious exploration practices. The integration of these advanced methods promotes a more sustainable approach to mineral and resource extraction, which is crucial for balancing economic growth with environmental preservation in geologically sensitive areas. Ultimately, this work provides a thorough geological interpretation that not only aids future exploration efforts but also aligns with the global push for sustainable and eco-friendly resource management.

Innovative Magnetic Gear Design Incorporating Electromagnetic Coils for Multiple Gear Ratios

In this study, a novel magnetic gear design is introduced. Unlike conventional magnetic gears that can only achieve a single gear ratio using permanent magnetic poles, the proposed design incorporates electromagnetic coils that can adapt to various control strategies, resulting in a multiple gear ratio for the same machine design. We selected a gear system with five gear ratios to validate the new design. The performance of the proposed design was compared with that of the conventional magnetic gear. While permanent magnet poles offer high torque transmission with a small volume, they cannot provide different gear ratios for the same configuration. Therefore, this work suggests using a single-gear machine based on a fixed number of electromagnetic coils to achieve different gear ratios. This research outlines the design steps, simulation process, and detailed analysis. The results demonstrate the effectiveness of the proposed design strategy, which can be potentially applied to wind turbines, transportation, and other scenarios with comparable success.

The influence of the solar wind electric and magnetic fields on the latitude and temporal variations of the current density, JZ, of the global electric circuit, with relevance to weather and climate

Observations have shown small day-to-day stratiform cloud opacity and atmospheric dynamical responses to variations in the ionosphere-earth current density (JZ). We model the day-to-day and seasonal/bi-decadal changes in the area-integrals of ionospheric potential (Vi) near the magnetic poles due to solar wind electric field inputs. The overhead value of Vi, divided by the local column resistance (R) determines JZ, where the conductivity of the column is the result of ionization by galactic cosmic rays (GCRs) and solar and magnetospheric energetic particle precipitation. These vary with time, due to varying solar wind magnetic field inputs, not only on the day-to-day timescale (e.g., Forbush decreases) but also on the decadal and bi-decadal and century timescales. The GCR and energetic particle inputs vary with latitude, due to filtering of particle energies in the geomagnetic field. We compare area-integrals of the amplitude of the JZ variations due to Vi changes to those due to the R changes, for evaluating their global effectiveness in affecting cloud microphysics and weather and climate changes. The day-to-day and bi-decadal correlated weather and climate variations indicate JZ rather than other solar forcings as mainly responsible for the correlations. The decadal and longer climate responses to space weather are not large; however, understanding them could help improve predictions of future climate change due to greenhouse gases.

Mechanism analysis of enhanced desulfurization of pulverized coal through high-gradient magnetic separation with microwave radiation

Dry high gradient magnetic separation technology is a low-carbon green technology. It can be embedded in a power plant to remove coal pyrite with a high-efficiency magnetic separator and remarkable magnetic properties difference between coal pyrite and coal matrix. This study selected the microwave radiation method to improve the magnetic properties difference and carried out a desulfurization experiment with a self-developed high-gradient permanent magnetic separator using the tapered iron auxiliary magnetic pole. The results demonstrate that the pyrite content and specific magnetic susceptibility increase with the decrease in particle size. The desulfurization rate did not change significantly at 25 °C. The coal sample began to appear in the thermal reaction at 450 °C, and the pyrite can become a strong magnetic property pyrrhotite. The desulfurization rate can achieve 58.70 % at 700 °C, and is equivalent to the wet washing index, due to the supply of high magnetic field force. The dynamic characteristic response of magnetic particles becomes more obvious with short time adsorption, and the probability of carrying non-magnetic particles is reduced. This study demonstrates that the high-gradient magnetic separation technology of pulverized coal enhanced by microwave irradiation is feasible.

Thrust ripple suppression analysis of moving-magnet-type linear synchronous motor based on independent coil

In this paper, a novel thrust ripple suppression method for multi-secondary permanent magnet synchronous linear motor based on independent coil structure is proposed. Independent coil structure can realize independent power supply for each coil by changing the driving mode of the coils. Combined with the new power supply strategy, the detent and electromagnetic force fluctuation can be suppressed. Firstly, the cogging and end force of moving-magnet-type linear motor are separated by periodic and vector boundary conditions and harmonic analysis is carried out. An analytical model of air gap magnetic field based on virtual magnetic poles is established to solve the back EMF and electromagnetic force fluctuation of the motor. The generation mechanism and harmonic of electromagnetic force fluctuation are analyzed. A multi-secondary PMLSM based on independent coil is proposed, the principle of suppressing motor thrust ripple is expounded, and the coupling effect between modules is analyzed. Finally, a zero-crossing power supply strategy is proposed. The simulation and experimental results show that multi-secondary independent coil PMLSM can effectively suppress the detent and electromagnetic force fluctuation.

Simulation method of heat-mass transfer between hot wind and wet coating in the manufacturing process of pole piece

In order to improve the complex numerical calculation process for wet coating of pole piece, a three-dimensional numerical model of heat-mass transfer characteristics is established between hot wind and wet coating based on multi-field coupling theory of porous media and meshless parallel method, and its reliability is verified through literature data. Meanwhile, the difference calculation method and evaluation process are proposed for heat-mass transfer characteristics to solve this numerical model. The results show that the maximum errors are less than 14.7 % for this model. In addition, a scale modeling method is proposed to improve computational efficiency based on similarity theory. Meanwhile, the influences of different scale factors on temperature and humidity parameters are analyzed for wet coating. The results show that this method is accurate and reliable because the determination coefficient R2 of all parameters is more than 0.99. Meanwhile, compared with the calculation time of original model, the calculation efficiency increases by 44.6 % for the model with scale factor selected as 800. Finally, the variation and distribution of internal parameters are analyzed for wet coating during pore emptying process based on above simulation method. The results show that the variation trends of liquid film thickness, pore emptying rate, water saturation, gas saturation and effective gas diffusion coefficient are corresponding with the accelerated, uniform and decelerated drying processes of porous media. Meanwhile, the location of four-corner edges for wet coating is the weak link in heat-mass transfer process. Therefore, the heat-mass transfer characteristics for wet coating can be improved by increasing its initial thickness or adjust reasonable drying position in engineering.

Numerical study on heat transfer and pressure performance of different suspension nozzles

The drying process of the lithium battery pole pieces makes extensive use of the suspension nozzle. It is of great significance to study the heat transfer and pressure steady-state characteristics of the suspension nozzle and to select the appropriate nozzle structure for the production of pole pieces. Based on the SSTk-ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{SST }}k - \\omega$$\\end{document} turbulence model, this article numerically simulates the impact jet process of suspension nozzles with slits, injection holes, and effusion holes. There is a qualitative and quantitative analysis of the distribution of their velocity field, temperature field, local Nusselt number, average Nusselt number, local pressure coefficient, and average pressure coefficient, and the comprehensive performance index of the nozzle is proposed. The results show that when the weight factor of heat transfer performance α is less than 21.61% and the weight factor of pressure performance β is more than 78.39%, the comprehensive performance of the traditional suspension nozzle with double slits is the best. As the α is increasing, the β is decreasing. The comprehensive performance of the suspension nozzle with effusion holes is the best. The turbulent intermittence, interaction between neighbouring jets, and edge effects affect the heat transfer and pressure uniformity of the suspension nozzle.

Calculation of AC loss using 2D homogenization method for HTS synchronous condenser rotor and validation

Compared with low-temperature superconductors, second-generation high-temperature superconducting materials offer higher current densities and temperature margins, which provide a boost to the development of superconducting condenser towards large capacity and light weight. In this paper, a 3D-to-2D dimensionality reduction and simplification method is proposed to address the problem of massive computation of 3D finite element model during the optimization of superconducting condenser rotor performance parameters. This method splits the pole based on the geometric characteristics of the rotor pole, establishes a 2D simplified model of each part of the pole after splitting, and uses the simplified model to calculate the key physical quantities such as the magnetic field, AC loss, temperature change, etc., during the excitation process of the superconducting condenser rotor. This method effectively reduces the computational complexity of the model and improves the efficiency of the calculation and iterative optimization of the magnet pole parameters. In order to verify the correctness of the electromagnetic calculation results of the simplified model, the rotor magnet model was assembled to carry out experiments in liquid nitrogen bath, and the experimental results were in good agreement with the calculation results.

A Relational Approach to Event Sustainability: Applying Actor‐Network Theory and Foucauldian Discourse Analysis to a Music Event

The framing of event sustainability should go beyond the greening of specific events and the event sector. Based on a relational approach, we used actor‐network theory and Foucauldian discourse analysis to investigate the debate on a music event sustainability. We collected and discursively analyzed online newspapers and social media data regarding this event’s sustainability. The findings showed a polarized discourse characterized by conflicting views on, for example, nature, and three missing discourses–academic, local community, nonhuman–which we identified as alternative discourses and leverage points for greater sustainability. These findings allowed us to conceptualize event sustainability as a catalyzing network of actors, ideas, and relationships attracted to magnetic poles powered by different understandings of central concepts. This study proposes an understanding of event sustainability in relational terms and its contribution resides in the combination of actor‐network theory and Foucauldian discourse analysis as a possible approach to such understanding.

Atmospheric heating and magnetism driven by 22Ne distillation in isolated white dwarfs

The origin of atmospheric heating in the cool, magnetic white dwarf GD 356 remains unsolved nearly 40 years after its discovery. This once idiosyncratic star with Teff ≈ 7500 K, yet Balmer lines in Zeeman-split emission is now part of a growing class of white dwarfs exhibiting similar features, and which are tightly clustered in the HR diagram suggesting an intrinsic power source. This paper proposes that convective motions associated with an internal dynamo can power electric currents along magnetic field lines that heat the atmosphere via Ohmic dissipation. Such currents would require a dynamo driven by core 22Ne distillation, and would further corroborate magnetic field generation in white dwarfs by this process. The model predicts that the heating will be highest near the magnetic poles, and virtually absent toward the equator, in agreement with observations. This picture is also consistent with the absence of X-ray or extreme ultraviolet emission, because the resistivity would decrease by several orders of magnitude at the typical coronal temperatures. The proposed model suggests that i) DAHe stars are mergers with enhanced 22Ne that enables distillation and may result in significant cooling delays; and ii) any mergers that distill neon will generate magnetism and chromospheres. The predicted chromospheric emission is consistent with the two known massive DQe white dwarfs.

Analysis of the Eddy current of water heating device to convert wind energy directly into heat: Case study maldo island, South Korea

The Eddy Current of Water Heating (ECWH) system introduces a pioneering approach for converting wind energy into heat, marking a significant step in renewable energy technology. The current study focuses on refining the ECWH system by evaluating eight distinct heat generator models. Each model is selected based on its magnet configurations and pole numbers to maximize power efficiency at rotational speeds ranging from 100 to 500 rpm. This selection strategy is designed to provide a deep understanding of not only system efficiency across a spectrum of technical specifications but also the practical limitations of experimental research considerations. Energy efficiency is thoroughly analyzed for four models over a power input range of 120 to 2193 W. Wind speed data collected over a year from Maldo Island, west coast of South Korea, simulates the Weibull distribution of wind speeds and estimates total power production by employing the QBlade software. This study aims to explore the practicality of converting wind's kinetic energy directly into thermal energy through the ECWH system. Our findings indicate that the ECWH system outperforms conventional permanent magnet alternators, particularly in its ability to generate more power at lower angular velocities and wind speeds—a crucial feature for locales like Maldo Island, where typical wind speeds range from 3 to 6 m/s, considered low to moderate. With an energy efficiency exceeding 90%, generating an annual power output of 2266.3 kWh, and achieving a facility utilization rate of 10.34%, the results underscore the potential of the ECWH system as an efficient and sustainable solution for heating in areas with similar wind conditions.

Оценки положения Северного магнитного полюса в 2021 году

Based on measurements of magnetic declinations with standard shipboard instruments in three marine expeditions in the Russian Arctic, estimates of the Earth`s North Magnetic Pole position in 2021 were obtained. It is located in the Russian sector of the Arctic. Experiments on determining the North Magnetic Pole in 2021 were carried out on board the research vessels “Professor Molchanov” and the scientific expedition one “Mikhail Somov” supported by the hydrographic ship of “Horizon”. The calculations used a comparison of measurements along the quasi-closed route with magnetic declination data using the International Geomagnetic Analytical Field IGRF13 (International Geomagnetic Reference Field) model with the choice of the minimum discrepancy, a simple inverse matching problem for smooth functions was solved. The results obtained confirm the possibility of regular operational assessment of the Earth`s magnetic poles position. The technology of assessing the magnetic deviation of ships is considered

Detecting life by behavior, the overlooked sensitivity of behavioral assays

Detecting life has driven research and exploration for centuries, but recent attempts to compile and generate a framework that summarizes life features, aimed to develop strategies for life detection missions beyond planet Earth, have disregarded a key life feature: behavior. Yet, some behaviors such as biomineralization or motility have occasionally been proposed as biosignatures to detect life. Here, we capitalize on a specific taxis’ motility behavior, magnetotaxis, to experimentally provide insights in support of behavior as an unambiguous, sensitive biosignature, and magnetic forces as a prescreening option. Using a magnetotactic bacterial species, Magnetospirillum magneticum, we conducted a lab sensitivity experiment comparing PCR with the hanging drop behavioral assay, using a dilution series. The hanging drop behavioral assay visually shows the motility of MTB toward magnetic poles. Our findings reveal that the behavioral assay exhibits higher sensitivity in the detection of M. magneticum when compared to the established PCR protocol. While both methods present similar detection sensitivities at high concentrations, at ≥ 10–7 fold dilutions, the behavioral method proved more sensitive. The behavioral method can detect bacteria even when samples are diluted at 10–9. Comparable results were obtained with environmental samples from the Hula Valley. We propose behavioral cues as valuable biosignatures in the ongoing efforts of life detection in unexplored aquatic habitats on Earth and to stimulate and support discussions about how to detect extant life beyond Earth. Generic and robust behavioral assays can represent a methodological revolution.