Search

Magnetic Resonance Imaging linear-accelerator (MRI-linac) equipment has recently been introduced to multiple centres in Australia and New Zealand. MRI equipment creates hazards for staff, patients and others in the MR environment; these hazards must be well understood, and risks managed by a system of environmental controls, written procedures and a trained workforce. While MRI-linac hazards are similar to the diagnostic paradigm, the equipment, workforce and environment are sufficiently different that additional safety guidance is warranted. In 2019 the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) formed the Magnetic Resonance Imaging Linear-Accelerator Working Group (MRILWG) to support the safe clinical introduction and optimal use of MR-guided radiation therapy treatment units. This Position Paper is intended to provide safety guidance and education for Medical Physicists and others planning for and working with MRI-linac technology. This document summarises MRI-linac hazards and describes particular effects which arise from the combination of strong magnetic fields with an external radiation treatment beam. This document also provides guidance on safety governance and training, and recommends a system of hazard management tailored to the MRI-linac environment, ancillary equipment, and workforce., (© 2023. The Author(s).)

THE ARTS The Painter’s Papers A prairie mystic in his own words Kelvin Browne Lionel LeMoine FitzGerald was quiet in person but demonstrative in writing.David Parkins Some Magnetic Force: Lionel [...]

In this work, we report a unique and facile approach to the manufacture of fluorine-free superamphiphobic paper. Based on the principle that Fe3O4 nanoparticles (NPs) arranged along the direction of a magnetic field, the mixture of Fe3O4 NPs and polydimethylsiloxane (PDMS) was coated on kraft paper through self-assembly and thermal-curing at a high temperature in a magnetic field, fabricating a mushroom-like microstructure on the paper. At an Fe3O4 NPs content of 75%, the radius of the mushroom-like pillar caps (RCAP) and center-to-center spacing between two pillars (S) obtained the optimal size of 37 ± 18 μm and 237 ± 38 μm, respectively. The oil-contact angle and water-contact angle of the fabricated paper were up to 156° and 160.4°, respectively. It also showed excellent oleophobic stability; the oil-contact angle was still maintained at 141.9° after 1 h. In addition, the contact angles of milk, ethylene glycol and castor oil were all above 150°, and the contact angle of diiodomethane was 134.2°. Moreover, the sample showed great oil resistance with a kit rating value of 12/12 and permeability of 1800+ s. [ABSTRACT FROM AUTHOR]

Paper based lateral flow systems are widely used biosensor platforms to detect biomolecules in a liquid sample. Proteins, bacteria, oligonucleotides, and nanoparticles were investigated in the literature. In this work we designed a magnetic platform including dual magnets and tested the flow of micron size immunomagnetic particles alone and when loaded with cells on two different types of papers. The prewetting conditions of the paper and the applied external magnetic field are the two dominant factors affecting the particle and cell transport in paper. The images recorded with a cell phone, or with a bright field optical microscope were analyzed to measure the flow of particles and cells. The effect of prewetting conditions and magnetic force were measured, and it was shown that in the worst case, minimum 90% of the introduced cells reached to the edge of the paper. The paper based magnetophoretic lateral flow systems can be used for cell assays. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Background: Magnetic nanoparticles (MNPs) are used as tracers without ionizing radiation in vascular imaging, molecular imaging, and neuroimaging. The relaxation mechanisms of magnetization in response to excitation magnetic fields are important features of MNPs. The basic relaxation mechanisms include internal rotation (Néel relaxation) and external physical rotation (Brownian relaxation). Accurate measurement of these relaxation times may provide high sensitivity for predicting MNP types and viscosity-based hydrodynamic states. It is challenging to separately measure the Néel and Brownian relaxation components using sinusoidal excitation in conventional MPI., Purpose: We developed a multi-exponential relaxation spectral analysis method to separately measure the Néel and Brownian relaxation times in the magnetization recovery process in pulsed vascular MPI., Methods: Synomag-D samples with different viscosities were excited using pulsed excitation in a trapezoidal-waveform relaxometer. The samples were excited at different field amplitudes ranging from 0.5 to 10 mT at intervals of 0.5 mT. The inverse Laplace transform-based spectral analysis of the relaxation-induced decay signal in the field-flat phase was performed by using PDCO, a primal-dual interior method for convex objectives. Néel and Brownian relaxation peaks were elucidated and measured on samples with various glycerol and gelatin concentrations. The sensitivity of viscosity prediction of the decoupled relaxation times was evaluated. A digital vascular phantom was designed to mimic a plaque with viscous MNPs and a catheter with immobilized MNPs. Spectral imaging of the digital vascular phantom was simulated by combining a field-free point with homogeneous pulsed excitation. The relationship between the Brownian relaxation time from different tissues and the number of periods for signal averages was evaluated for a scan time estimation in the simulation., Results: The relaxation spectra of synomag-D samples with different viscosity levels exhibited two relaxation time peaks. The Brownian relaxation time had a positive linear relationship with the viscosity in the range 0.9 to 3.2 mPa · s. When the viscosity was >3.2 mPa · s, the Brownian relaxation time saturated and did not change with increasing viscosity. The Néel relaxation time decreased slightly with an increase in the viscosity. The Néel relaxation time exhibited a similar saturation effect when the viscosity level was >3.2 mPa · s for all field amplitudes. The sensitivity of the Brownian relaxation time increased with the field amplitude and was maximized at approximately 4.5 mT. The plaque and catheter regions were differentiated from the vessel region in the simulated Brownian relaxation time map. The simulation results show that the Néel relaxation time was 8.33±0.09 μs in the plaque region, 8.30±0.08 μs in the catheter region, and 8.46±0.11 μs in the vessel region. The Brownian relaxation time was 36.60±2.31 μs in the plaque region, 30.17±1.24 μs in the catheter region, and 31.21±1.53 μs in the vessel region. If we used 20 excitation periods for image acquisition in the simulation, the total scan time of the digital phantom was approximately 100 s., Conclusion: Quantitative assessment of the Néel and Brownian relaxation times through inverse Laplace transform-based spectral analysis in pulsed excitation, highlighting their potential for use in multi-contrast vascular MPI., (© 2023 American Association of Physicists in Medicine.)

Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

MR-guided radiotherapy (MRgRT) is one of the most significant advances in radiotherapy in recent years. The hybrid systems were designed to visualize patient anatomical and physiological changes during the course of radiotherapy, enabling more precise treatment. However, before MR-linacs reach their full potential in delivering safe and accurate treatments to patients, the radiotherapy team must understand how a magnetic field alters the dosimetric properties of the radiation beam and its potential impact on treatment quality and clinical outcomes. This review aims to provide an in-depth description of the magnetic field induced dose effects for the two widely available systems, the 0.35 T and the 1.5 T MR-linacs. In MR-linac treatments, the primary photon beam passes through MR components that never exist in conventional linacs, which alter both in-field and out-of-field doses. More importantly, the interplay between the always-on magnetic field and the secondary electrons is not negligible. This interplay affects dose deposition in the patient, resulting in reduced in-field skin dose due to purged-out contaminant electrons, shortened build-up distance and a shifted crossline profile owing to asymmetric dose kernel. Especially two effects, namely, electron return effect (ERE) and electron stream effect (ESE), are not seen in conventional radiotherapy. This review also summarizes the clinical observations on the site-specific treatments influenced mostly by the magnetic field. In MR-linac treatment, the head and neck region is one of the most challenging sites as ERE occurs at low and high density tissue interfaces and around air cavities, generating hot and cold spots. In breast cancer treatment, consideration should be given to the increased in-field skin dose induced by ERE and the increased out-of-field dose caused by ESE for regions such as the ears, chin, and neck. In lung cancer treatments, tissue inhomogeneity combined with ERE will exacerbate target dose heterogeneity and increase or decrease interface dose. Lastly, treatment in the abdomen and pelvic region will be affected by the presence of gas pockets near the target. The review provides practical recommendations to mitigate these effects., (© 2023 American Association of Physicists in Medicine.)

Developing high-efficiency electrocatalysts for the hydrogen evolution reaction (HER) is of great importance. In this paper, dendrite-free Ni–Cu catalysts were synthesised via one-step pulse electrodeposition under a weak magnetic field (0.5 T). Regardless of the direction of the magnetic field, the ions were affected by the magnetohydrodynamic (MHD) effect, which greatly promoted the mass transfer and dispersion uniformity, and suppressed the uncontrollable agglomeration by electrodeposition. It was found that the nucleation mechanism changed from progressive nucleation under a 0 T magnetic field to instantaneous nucleation under a 0.5 T magnetic field. Large-scale (325 nm, 0 T) dendrite growth on the single-sided plane was successfully suppressed, and replaced by smaller (90 nm, 0.5 T) and uniformly distributed cluster growth around the carbon paper. In addition, the (111) plane was strengthened by the magnetic field. Electrochemical analysis showed that the Ni–Cu catalysts exposed more surface area and exhibited greatly enhanced catalytic activity, which only needed −57.3 mV to deliver the current density of 10 mA cm−2 with a small Tafel slope of 99.4 mV dec−1 in 1 M KOH. Overall, magneto-electrodeposition, especially under weak magnetic field conditions, provides great promise for the preparation of HER catalysts. [ABSTRACT FROM AUTHOR]

• The external magnetic field dramatically improved the analysis sensitivity of paper-based PEC biochip. • Electron spin polarization boosted photoinduced charge separation in sulfur-defected CdIn 2 S 4 /FeOOH and ferromagnetic ZnFe 2 O 4. • The ferromagnetic ZnFe 2 O 4 nanosphere was utilized as a multiple signal amplifier with strong quenching effects. • Enzymatic catalytic precipitation reaction was introduced for ultrasensitive detection of chlorpyrifos in real samples. Efficient carrier separation plays an utterly pivotal role in enhancing the sensitivity of photoelectrochemical (PEC) analysis. Here we report a concise yet powerful strategy of electron spin polarization induced by magnetic stimulation, to effectively modulate the efficiency of charge separation in a paper-based PEC (μ-PEC) sensing system. The electronic configuration of the sulfur-defected CdIn 2 S 4 /FeOOH photoactive matrix and ferromagnetic ZnFe 2 O 4 signal label were regulated via the electron parallel alignment along with spin state flip and reconstruction at particular active sites under external magnetic field, significantly facilitating the separation of photoinduced carriers. As a proof-of-concept application, the magnetic-triggerable spin-state reconfiguration coupled with enzymatic catalytic precipitation reaction was developed for detection of chlorpyrifos with a wide linear range of 10-2.5-106 ng mL−1 and low detection limit of 0.67 pg mL−1. This work provides the basis for understanding the role of magnetic stimulus in tailoring charge separation and constructing a universal strategy for high performance μ-PEC bioanalysis. [ABSTRACT FROM AUTHOR]

Background: Fluoroscopically-guided procedures at our hospital have been aborted due to sigmoidal distortion (S-distortion) when an image intensifier (II) system is used in a surgical environment distant from any apparent sources of strong magnetic fields, such as a nearby magnetic resonance imaging (MRI) scanner. Clearly, current clinical practice fails to account for the impact of ambient weak magnetic fields and/or other contributing factors on S-distortion induction., Purpose: This study attempts to quantitatively assess the threshold level of magnetic field, along with other potential factors, that can induce intolerable S-distortion during image-intensified fluoroscopically-guided procedures. We will also discover the origins of such level of magnetic field in typical surgical facilities and provide our practical mitigation strategies accordingly., Methods: Ten surgical facilities and their accessory equipment (e.g., surgical tables) were screened using an AC/DC gaussmeter for the distribution and magnitude of magnetic field (magnetic flux density). A 'hot spot' of magnetic field was identified to further investigate the induction of S-distortion by scanning a titanium rod phantom using a GE OEC 9900 Elite II system placed at increasing distance from the 'hot spot' corresponding to decreasing magnetic field experienced by the II. The measurements were compared to that on a 'cold spot', and a GE flat panel detector (FPD) fluoroscopy was used as the negative control. Rod phantoms made of various magnetic susceptible materials (titanium, steel, aluminium, and copper) were scanned to explore the potential effects of implant material on S-distortion. An upper extremity anthropomorphic phantom was imaged on various surgical tables to mimic clinical sceneries. The GE II model and Siemens ARCADIS Orbic II model were compared to evaluate if S-distortion induction varied among different II models. Two metrics, angle of rotation (θ) and deviation/length ratio, were used to quantify the degree of S-distortion. Three designs of external magnetic shielding were evaluated for mitigating S-distortion., Results: We identified static magnetic fields up to 2500 µT and 70 µT on the floor and at 1-meter height, respectively, in random locations of surgical facilities. A large variation of magnetic field (64 ± 20 µT) was detected on the surface of surgical tables, with background magnetic fields of ∼35 µT. Quantitative assessments demonstrated that even weak magnetic fields at sub-Gauss level (<100 µT) could induce noticeable distortion artifacts, deemed unacceptable (θ > 4°). S-distortion was independent of the implant material being imaged but dependent on the II model - the threshold magnetic fields (4° distortion induction) were as low as 47 µT and 94 µT for the GE and Siemens II models. Mitigation possibilities of S-distortion include relocating the II to an area with subthreshold magnetic fields and shielding the II utilizing cylindrical mu-metal shields with an extension for alleviating the effect of openings., Conclusions: This work demonstrates that ambient sub-Gauss magnetic fields originating from any possible sources in a surgical environment have to be carefully considered when performing an image-intensified fluoroscopically-guided procedure, because such weak magnetic fields are likely able to induce unacceptable S-distortion artifacts in the acquired X-ray images leading to undesirable surgical outcomes., (© 2022 American Association of Physicists in Medicine.)

A Conductor on Round Core (CORC) cable wound with a high-temperature superconductor is an important cable concept for high-current density applications. It is widely used in large power systems because of its advantages of good flexibility and high engineering current density. However, the complex design structure of CORC cable makes it very difficult to understand its electromagnetic properties (such as AC loss). In particular, the different winding directions of each layer in multi-layer cable have a great influence on its electromagnetic characteristics. In this paper, the H-method is used to solve the electromagnetism and mechanics equations. The influence of the winding direction of CORC cable on its electromagnetic field distribution characteristics, AC loss, and mechanical variation under the action of external magnetic field is investigated. The AC loss study of single-layer cable reveals that when the applied magnetic field is increased from 0.01 to 0.02 and 0.03 T, the AC loss peak of the cable increases by 107 and 103 orders of magnitude, respectively, indicating that the effect of low applied magnetic field on the AC loss of the cable is more significant. For multi-layer cables, cables with opposite winding directions have a greater depth of current density penetration than cables with the same winding direction. In addition, the mechanical variations of multi-layer cables with different winding orientations are explored. The results show that the Mises stress in the cable with the same winding direction is about 32% higher than that of the cable with the opposite winding direction, which indicates that the method of winding the cable in the opposite direction between adjacent layers of tape can avoid excessive mechanical stress. [ABSTRACT FROM AUTHOR]

Magnetic sensors are widely used in our daily life for assessing the position and orientation of objects. Recently, the magnetic sensing modality has been introduced to electronic skins (e-skins), enabling remote perception of moving objects. However, the integration density of magnetic sensors is limited and the vector properties of the magnetic field cannot be fully explored since the sensors can only perceive field components in one or two dimensions. Here, we report an approach to fabricate high-density integrated active matrix magnetic sensor with three-dimensional (3D) magnetic vector field sensing capability. The 3D magnetic sensor is composed of an array of self-assembled micro-origami cubic architectures with biased anisotropic magnetoresistance (AMR) sensors manufactured in a wafer-scale process. Integrating the 3D magnetic sensors into an e-skin with embedded magnetic hairs enables real-time multidirectional tactile perception. We demonstrate a versatile approach for the fabrication of active matrix integrated 3D sensor arrays using micro-origami and pave the way for new electronic devices relying on the autonomous rearrangement of functional elements in space. State-of-the-art magnetic skins can only sense in one or two-dimensions, at small spatial resolutions. By combining the ancient art of paper folding, origami, with advanced semiconductor technology, here, authors present cutting edge three-dimensional magnetic sensors. [ABSTRACT FROM AUTHOR]

Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

This paper challenges the traditional focus on mere competency and charisma in the ever-shifting terrain of leadership, arguing they hold limited power in navigating the complexities of modern environments. While proficiency in one's field and magnetic charm remain valuable, they fall short in fostering collaborative, equitable, and sustainable success. Delving into the limitations of both concepts, the paper unveils a broader tapestry of leadership requisites. Emotional intelligence, the cornerstone of building strong relationships and effectively managing team dynamics, takes center stage. Humility, embracing feedback and empowering others, fosters collaborative decision-making. Authenticity, radiating genuineness and trust, creates a foundation for shared commitment. Finally, ethical behavior, anchored in integrity and stakeholder wellbeing, ensures responsible and impactful leadership. Drawing upon scholarly insights and real-world experiences, the paper advocates for a holistic approach to leadership development, one that cultivates a diverse skillset and ethical behavior, enabling leaders to not only survive but also thrive in the demanding landscape of the 21st century. The paper emphasizes the need for a multifaceted leadership equipped to tackle the dynamic challenges of our time. [ABSTRACT FROM AUTHOR]

The impact of a time-varying external magnetic field on carbon nanotubes has been studied using Maxwell's equations in the mentioned articles. However, the Maxwell's equations are erroneously presented in the papers. The incorrect Maxwell's equations, their derivatives, and the Lorentz force equations have all been examined in this work. In this article, we have endeavored to ensure that the equations are formatted correctly and have made an effort to do so. We have made an effort to intuitively correct the equations' errors. We did not comment on the other portions of the mentioned articles; instead, we restricted ourselves to the examination of the impact of Maxwell's equations and Lorentz force equations. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

The permeability of permalloy at ultra-low-frequency magnetic field is a crucial and fundamental parameter for analyzing the low frequency shielding factor of magnetically shielded rooms. However, due to limitations in the accuracy of the existing magnetic flux signal measuring system, the permeability at ultra-low-frequency magnetic field is challenging to precisely determine. Therefore, a high-precision voltammetry method for measuring the permeability of permalloy at ultra-low-frequency magnetic field is proposed in this paper. First, the theory of the voltammetry method and the required level of induced voltage accuracy are derived and thoroughly analyzed. Then, the voltage acquisition module with ultra-low noise is designed by using four parallel instrumentation amplifiers, and the magnitude of the noise is quantified by establishing the noise analysis model for the voltage acquisition module. Finally, the system for measuring the permeability at ultra-low-frequency magnetic field is set up, and its feasibility is verified by comparing the measurement results of permeability at 10 Hz with the commercial soft magnetic instrument. The results show that the system is capable of measuring the permeability of permalloy at 0.01 Hz to 1 Hz, with repeatability error of less than 3%. The method can also be applied to measure the permeability of other soft magnetic materials. [ABSTRACT FROM AUTHOR]

Summary: For wireless power transfer system (WPTS), the deflection of the resonant coil and the increase of the transmission distance will cause a sharp decline in transmission efficiency. This paper presents a novel long‐distance and anti‐deflection wireless power transfer based on concentric three‐coil resonator and inhomogeneous electromagnetic metamaterials (IEM). First, the effective receiving area of the resonator is analyzed, and the anti‐disturbance concentric three‐coil resonator is designed quantitatively. Considering the magnetic field distribution generated by the transmitting coil, this paper proposes and designs IEM with three kinds of effective permeability, which is applied in different design area, respectively. Meanwhile, the finite‐element‐method simulation proves an improvement in magnetic field modulation and flux leakage control when WPTS with IEM is used. The experimental results show that, compared with the traditional one‐coil to one‐coil, the WPTS designed in this paper achieves an increase of 43% in the efficiency at a 90° deflection. Furthermore, the efficiency of WPTS with IEM is 17% and 7% higher than that of WPTS with homogeneous electromagnetic metamaterials (HEM) and without electromagnetic metamaterials. As a result, the design method in this paper can improve the anti‐disturbance capability and increase the transmission distance and efficiency. [ABSTRACT FROM AUTHOR]

The IPT system has been studied for underwater applications such as autonomous underwater vehicles (AUVs) and subsea sensors. However, it rarely comparatively shows the performance of the IPT system in air, freshwater, and seawater. Based on the fore‐mentioned research background, this paper presents a survey of the properties of the IPT system in different mediums. Here, a 100 W power‐level experimental IPT prototype is built and tested. The resonant frequency is set at 300 kHz with a gap range from 10 to 190 mm. The comparison is focused on the efficiency, mutual inductance, coupling coefficient, coil resistance, and quality factor of the IPT system. The IPT system is placed in air, freshwater, and seawater with the same settings. What's more, the magnetic fields of coupling coils in air, freshwater, and seawater are presented in this paper. This paper could be acted as a reference to optimize the IPT system and facilitate future IPT research for underwater applications by analysing the performance of the IPT system in different mediums. The 3D Ansys Maxwell simulation of the IPT system is also given here to study the magnetic fields. [ABSTRACT FROM AUTHOR]

Eddy current inspection has been extensively employed in non-destructive testing of various conductive materials. The coil probe, as a mainstream sensor in the eddy current detection system, inevitably encounters interference from external signals while transmitting its own signal. Therefore, developing techniques to extract valuable signals from noisy ones is crucial for ensuring accurate detection. Carbon fiber composites not only possess significantly lower electrical conductivity compared to conventional metallic materials but also exhibit notable anisotropy. To address this issue, we designed an '8' coil probe set where the excitation coil does not electromagnetically interfere with the detection coil. However, practical applications that require portability and miniaturization pose challenges when utilizing this coil probe set to identify carbon content or defects due to the typically weak output signal. To address this issue, this paper proposes a design that combines the '8' structure of the planar coil probe with the principle of phase-locked amplification to create a dual-phase sensitive phase-locked amplification detection circuit. These specific design ideas were tested using a weak signal, which passed through the preamplifier, secondary amplifier, and band-pass filter comprising the target channel for signal amplification and noise filtering. The effective signal amplitude is proportional to the inverse phase difference between the direct current (DC) signal and inversely proportional to the amplitude of the signal. Finally, the DC signal was passed through an analog-to-digital converter (ADC). The analog-to-digital converter (A/D) is used to collect and calculate the DC signal, enabling the detection of weak electrical signals. Simulation experiments demonstrated that the signal detection circuit has an amplitude error below 0.2% and a phase error below 0.5%. The phase-locked amplification circuit designed in this paper can effectively extract the tiny impedance change signals of the planar coil sensor probe with high sensitivity and good robustness. [ABSTRACT FROM AUTHOR]

The state detection of power cables is very important to ensure the reliability of the power supply. Traditional sensors are mostly based on electric field detection. The operation is complex, and its efficiency needs to be improved. This paper optimizes the design and development of the magnetic field detection sensor for AC power cables. First, through the establishment of the magnetic field sensor model, it is determined that permalloy is the material of the magnetic core, the optimal aspect ratio of the magnetic core is 20, and the ratio of coil length to core length is 0.3. Second, the coil-simulation model is established, and it is determined that the optimal number of turns of the coil is 11,000 turns, the diameter of the enameled copper wire is 0.08 mm, and the equivalent magnetic field noise of the sensor is 0.06 pT. Finally, the amplifying circuit based on negative magnetic flux feedback is designed, the sensor is assembled, and the experimental circuit is built for the sensitivity test. The results show that the sensitivity of the magnetic field sensor is 327.6 mV/μT. The sensor designed in this paper has the advantages of small size, high sensitivity, ease of carry, and high reliability. [ABSTRACT FROM AUTHOR]

In the above paper, there are some typographical errors and some serious errors. [ABSTRACT FROM AUTHOR]

TEAM Problem 35, a benchmark problem in the optimization of electrical equipment, is a multi-objective, multi-variable optimization problem involving uniform field optimization. This paper proposes a novel guided optimization algorithm to address this problem and achieve optimal magnetic field regulation. First, the deep learning method is used to predict the magnetic field of the solenoid; second, the generated magnetic field cloud map is screened to extract the magnetic field information of the more optimal solution with uniform magnetic field distribution by calculating the variance of the generated magnetic field map; finally, the magnetic field features are combined with the particle swarm optimization algorithm; specifically, the variance of the calculated magnetic field map is added to the objective function of the optimization algorithm to strengthen the optimization process. This integration improves the convergence speed of the optimization process and ensures the continuity and stability of the obtained Pareto solutions. To optimize the solenoid, this paper considers the uniformity of magnetic field distribution and power loss as the primary optimization objectives. The radius of the coil is chosen as the design variable. The optimization results are compared with those obtained by conventional optimization algorithms, demonstrating superior optimization performance. [ABSTRACT FROM AUTHOR]

A hybrid excitation variable-leakage-flux machine (HE-VLFM) for electric vehicles is presented in this paper, which places the excitation windings on the outer side of the stator and provides an axial magnetic field through the magnetic-conducting ring and magnetic-conducting bridge. The HE-VLFM proposed in this paper has a rotor permanent magnet to provide the main magnetic field and an excitation winding to provide a variable auxiliary magnetic field, which can fulfill the requirements of the electric vehicle drive system with large torque at low-speed and wide speed regulation range. The electromagnetic performance of the proposed HE-VLFM is evaluated using the equivalent magnetic circuit method and three-dimensional finite element analysis, and the results show that the HE-VLFM has a well-developed regulating flux capability. [ABSTRACT FROM AUTHOR]

Inkjet printing of magnetic materials has increased in recent years, as it has the potential to improve research in smart, functional materials. Magnetostriction is an inherent property of magnetic materials which allows strain or magnetic fields to be detected. This makes it very attractive for sensors in the area of structural health monitoring by detecting internal strains in carbon fibre-reinforced polymer (CFRP) composite. Inkjet printing offers design flexibility for these sensors to influence the magnetic response to the strain. This allows the sensor to be tailored to suit the location of defects in the CFRP. This research has looked into the viability of printable soft magnetic materials for structural health monitoring (SHM) of CFRP. Magnetite and nickel ink dispersions were selected to print using the JetLab 4 drop-on-demand technique. The printability of both inks was tested by selecting substrate, viscosity and solvent evaporation. Clogging was found to be an issue for both ink dispersions. Sonicating and adjusting the jetting parameters helped in distributing the nanoparticles. We found that magnetite nanoparticles were ideal as a sensor as there is more than double increase in saturation magnetisation by 49 Am2/kg and more than quadruple reduction of coercive field of 5.34 kA/m than nickel. The coil design was found to be the most sensitive to the field as a function of strain, where the gradient was around 80% higher than other sensor designs. Additive layering of 10, 20 and 30 layers of a magnetite square patch was investigated, and it was found that the 20-layered magnetite print had an improved field response to strain while maintaining excellent print resolution. SHM of CFRP was performed by inducing a strain via bending and it was found that the magnetite coil detected a change in field as the strain was applied. [ABSTRACT FROM AUTHOR]

In wireless power transfer (WPT) systems, the horizontal misalignment between coils and variations in the load result in significant fluctuations in the transmission efficiency of the system. In this paper, a reverse series triple coil (RTC) structure is proposed. The RTC structure offers improved resistance to deflection in the direction of vehicle motion because of the magnetic field interaction of the reverse series coils. This adjustment helps maintain a more stable system transmission efficiency when the coils are deflected. At the same time, when the load resistance varies within a certain range, the system's transmission efficiency remains almost unchanged. This is because the addition of relay coils makes the system more adaptable to load changes and improves the system's load compatibility. The experimental results indicate that the RTC structure corresponds to 300% of the load variation range of the conventional reverse series dual-coil structure, within the range where the system transmission efficiency is not less than 95%, in the load variation range that satisfies the load equivalent resistance from 15O to 68O. During the offset process, the maximum system transmission efficiency fluctuation rate is 1.19% for a distance of 55% of the core width of the offset transmitting coil on the horizontal Y -axis, and the maximum efficiency reaches as high as 97.26%. [ABSTRACT FROM AUTHOR]

The performance requirements of motors are gradually increasing, and anisotropic soft magnetic materials have been applied in motors to improve performance, The magnetostriction of anisotropic soft magnetic materials is one of the main contributors in extensive research on anisotropic soft magnetic material transformers. Compared to transformers, the magnetic field in motors has more complex harmonic and multi-directional characteristics. In this paper, the magnetic field of motors stator teeth under both no-load and load conditions is calculated and analyzed to research magnetostriction of anisotropic soft magnetic materials in motor magnetic field and predict the NVH performance of anisotropic soft magnetic material motors accurately. Furthermore, the magnetostriction in different magnetization angles is investigated for the multi-directional characteristics, and the result is explained from microscopic principles. This paper focuses on a splicing oriented silicon steel (OSS) motor, the magnetization angle of OSS in motor varying from 0° to 90°. Firstly, the equivalent formulas of magnetic field are obtained under the analytical and finite element calculations. After that, the frequency and direction of experiment magnetic field are confirmed and the magnetostriction of OSS in different magnetization angle and frequency is measured. In the end, the variation character of magnetostriction of OSS is summarized. [ABSTRACT FROM AUTHOR]

This paper presents a design of a gyro‐TWT operating in the large‐orbit electron beam mode, with the aim of reducing the working magnetic field while ensuring operational efficiency. The periodic dielectric‐loaded structure, which has been successfully applied in the development of small‐orbit devices, is adopted as the high‐frequency interaction circuit. This paper conducts a comprehensive study and analysis of this structure and achieves stable operation in the Ka‐band after the optimization of the tube. This tube works at second harmonic of electron frequency in the mode of large‐orbit electron beam. The required magnetic field is only 5100 gauss, which can be generated using electromagnetic coils instead of superconducting magnets. The operational parameters include voltage of 75 kV, current of 9A, and velocity spread of 3.5%. Under these conditions, the device presents stable operation, with −3 dB bandwidth of 4.3 GHz, and maximum output power of 165 kW. This result meets the expected requirements for magnetic field and operational efficiency, thus validating the feasibility of practical fabrication of large‐orbit gyro‐TWT with periodic dielectric‐loaded structure. [ABSTRACT FROM AUTHOR]

A high-sensitivity plasmonic photonic crystal fiber (PCF) sensor is designed and a metal thin film is embedded for achieving surface plasmon resonance (SPR), which can detect the magnetic field and temperature simultaneously. Within the plasmonic PCF sensor, the SPR sensing is accomplished by coating both the upper sensing channel (Ch1) and the lower sensing channel (Ch2) with gold film. In addition, the temperature-sensitive medium polydimethylsiloxane (PDMS) is chosen to fill in Ch1, allowing the sensor to respond to the temperature. The magnetic field-sensitive medium magnetic fluid (MF) is chosen to fill in Ch2, allowing this sensor to respond to the magnetic field. During these processes, this proposed SPR-PCF sensor can achieve dual-parameter sensing. The paper also investigates the electrical field characteristics, structural parameters and sensing performance using COMSOL. Finally, under the magnetic field range of 50–130 Oe, this sensor has magnetic field sensing sensitivities of 0 pm/Oe (Ch1) and 235 pm/Oe (Ch2). In addition, this paper also investigates the response of temperature. Under the temperature range of 20–40 °C, Ch1 and Ch2 have temperature sensitivities of −2000 pm/°C and 0 pm/°C, respectively. It is noteworthy that the two sensing channels respond to only a single physical parameter; this sensing performance is not common in dual-parameter sensing. Due to this sensing performance, it can be found that the magnetic field and temperature can be detected by this designed SPR-PCF sensor simultaneously without founding and calculating a sensing matrix. This sensing performance can solve the cross-sensitivity problem of magnetic field and temperature, thus reducing the measurement error. Since it can sense without a matrix, it further can solve the ill-conditioned matrix and nonlinear change in sensitivity problems in dual-parameter sensing. These excellent sensing capabilities are very important for carrying out multiparameter sensing in complicated environments. [ABSTRACT FROM AUTHOR]

Abstract—We present a review of the papers written in the research field of stellar magnetism in 2021. The instruments, observation, and data analysis methods, photometry, spectroscopy, and spectropolarimetry results are considered. We present new data on magnetic fields of chemically peculiar stars and other objects of various types. [ABSTRACT FROM AUTHOR]

The bioconvective flows are truly connected to real-life and engineering development. So, the models of biomicrosystems and biocells are considered for the technical analysis in this paper. Our intention for the current analysis was to theoretically examine electrical conduction flow into mass and heat transfer by an extensive gyrotactic microorganism into an inclined magnetic field toward a vertical stretching sheet with nonlinear solar radiation with different solar thermal appliances. The effect on velocity slip and Joule heating was again studied in detail. This classical problem on Navier Stokes equations to the current imitation was decreased to ordinary differential equations by applying the comparison method. The numerical solutions were changed by boundary value problem (BVP) to clarify the subject into finite difference numerical scheme by applying MATLAB. The important results show that the density of motile microorganisms reduces to the bioconvection Lewis number and Peclet number, although reverse performance was noticed for the bioconvection Rayleigh number. Further, solar radiation fosters heat transport. In this paper, complete analysis is provided for potential functions of solar thermoelectric cells, solar ponds, solar thermal power fabrication, etc. [ABSTRACT FROM AUTHOR]

In this paper, we study the role of radiative cooling (RC) in a two-fluid model consisting of coupled neutrals and charged particles. We first analyse the linearized two-fluid equations where we include radiative losses in the energy equation for the charged particles. In a one-dimensional geometry for parallel propagation and in the limiting cases of weak and strong coupling, it can be shown analytically that the instability conditions for the thermal mode and the sound waves, the isobaric and isentropic criteria, respectively, remain unchanged with respect to one-fluid radiative plasmas. For the parameters considered in this paper, representative for the solar corona, the RC produces growth of the thermal mode and damping of the sound waves. In the weak coupling limit, the growth of the thermal instability and the damping of the sound waves is as derived in Field (Field 1965 Astrophys. J.142, 531 (doi:10.1086/148317)) using the charged fluid properties. When neutrals are included and are sufficiently coupled to the charges, the thermal mode growth rate and the wave damping both reduce by the same factor, which depends on the ionization fraction only. For a heating function that is constant in time, we find that the growth of the thermal mode and the damping of the sound waves are slightly larger. The numerical calculation of the eigenvalues of the general system of equations in a three-dimensional geometry confirm the analytic results. We then run two-dimensional fully nonlinear simulations that give consistent results: a higher ionization fraction or lower coupling will increase the growth rate. The magnetic field contribution is negligible in the linear phase. Ionization-recombination effects might play an important role because the RC produces a large range of temperatures in the system. In the numerical simulation, after the first condensation phase, when the minimum temperature is reached, the fraction of neutrals increases four orders of magnitude because of the recombination. This article is part of the theme issue 'Partially ionized plasma of the solar atmosphere: recent advances and future pathways'. [ABSTRACT FROM AUTHOR]

For the charged-particle dynamics under a strong and constant magnetic field, we consider and analyze exponential integrators in this paper. We derive two kinds of exponential integrators and study their long-time behavior by using the technique of modulated Fourier expansions. It is shown that a symmetric two-stage exponential integrator and some one-stage symplectic exponential integrators approximately conserve the energy and magnetic moment of the charged-particle dynamics over long times. [ABSTRACT FROM AUTHOR]

This paper describes a procedure for estimating the number of iterations in the main loop of a recently proposed algorithm designed to detect helical charged particle tracks in detectors submerged in a magnetic field. The calculations are based on a Monte Carlo simulation of the ATLAS inner detector. The resulting estimates of numerical complexity suggest that using the new procedure for online triggering is not feasible. There are however some areas, such as triggering for particles in a specific sub-domain of the phase space, where using this procedure might be beneficial. [ABSTRACT FROM AUTHOR]

Several papers reported the experimental phenomena of single crystal orthoferrite DyFeO3 samples: the sample magnetization increases with increasing temperature, under a constant low magnetic field along the easy magnetizing direction of the samples, and then reaches a maximum value. These phenomena are better explained using magnetic domain wall pinning at low temperatures and depinning at high temperatures, which were neglected in previous papers. In this article, we argue that the magnetic domain wall motion must be taken into consideration in order to explain these experimental phenomena. Based on an O 2p itinerant electron model, we discussed the role of the magnetic domain and the characteristics of cation magnetic moments in relevant single crystal materials. [ABSTRACT FROM AUTHOR]

The methodology for the evaluation of long-term exposure to the overhead line magnetic field is presented, in this paper. The developed methodology is based on the ambient temperature measurements and phase conductors' height measurements to find a linear regression model to determine phase conductors' height changes for different ambient temperatures. Based on the overhead transmission line geometry, and datasets about historical overhead line phase current intensity values and ambient temperatures long-term magnetic field exposure can be determined. For magnetic flux density determination, a method based on artificial neural networks is used. The methodology is applied to the case study of overhead line that connect substations Sarajevo 10 and Sarajevo 20. A period of one year is analyzed and magnetic flux density values are determined. The obtained results indicate that during the analyzed period for significant amounts of time magnetic flux density values surpass the recommended values for long-term exposure. [ABSTRACT FROM AUTHOR]

The crystallization of paramagnetic species in a magnetic field gradient under microgravity-like conditions is an area of interest for both fundamental and applied science. In this paper, a setup for the crystallization of paramagnetic species in the magnetic field up to 7 T generated by a superconducting magnet is described. The research includes calculations of the conditions necessary to compensate for the gravitational force for several types of paramagnetic substances using the magnetic field of superconducting magnets (4.7 T, 7 T, 9.4 T, and 16.4 T). Additionally, for the first time, the crystallization of copper sulfate and cobalt sulfate, as well as a mixture of copper sulfate and cobalt sulfate under gravitational force compensation in a superconducting magnet, was performed. This paper experimentally demonstrates the feasibility of growing paramagnetic crystals within the volume of a test tube on the example of copper and cobalt sulfate crystals. A comparison of crystals grown from the solution of a mixture of copper and cobalt sulfates under the same conditions, with and without the presence of a magnetic field, showed changes in both the number and size of crystals. [ABSTRACT FROM AUTHOR]