Search Results (2,889)

Integrated circuits (ICs), a major fraction of waste electrical and electronic equipment (WEEE), represent an important secondary source of gold (Au). However, recovering high-purity Au from ICs remains challenging due to the high silicon dioxide content that encapsulates Au within the IC core and the presence of complex base-metal mixtures that hinder selective purification. This study proposes a simplified end-to-end process that integrates mechanical liberation, magnetic separation, oxidative chlorination, ion-exchange purification and Au recovery from isolated ICs. Unlike conventional multi-stage comminution routes, the proposed pretreatment combines hydraulic pressing, milling/sieving and magnetic separation to maximize Au exposure while minimizing dust generation, metal losses and base-metal interference, which is subsequently subjected to oxidative leaching and purification. Optimal extraction conditions, determined through a Taguchi design (2.5 M HCl, 0.34 M NaClO, 40 °C, solid–liquid ratio 1 g/40 mL, 3 h), achieved a Au leaching efficiency of 89%. The resulting multi-metal leachate was treated with a strong anionic ion-exchange resin, increasing Au purity from 8% to 86% after thiourea elution in a sulfuric-acid medium. Final Au recovery was completed by reductive precipitation with sodium borohydride, yielding complete solidification (~100% efficiency). A comparative life-cycle assessment showed that this recycling route offers favourable environmental performance relative to primary mining. Beyond achieving efficient Au recovery, this work establishes an integrated recovery route for isolated ICs that combines process simplification with environmental positive impact, addressing an important gap in WEEE recycling. Full article

This study presents the design, manufacturing, and prototype-level evaluation of a high-efficiency interior permanent magnet synchronous motor (IPMSM) developed for compact electric vehicle traction applications. The proposed motor employs a 12-slot/10-pole spoke-type rotor topology and was evaluated in terms of electromagnetic performance, mechanical integrity, and thermal behavior. The slot–pole and winding configuration was assessed as part of the design evaluation, and the manufactured prototype was experimentally tested under different operating conditions. The experimental results were compared with numerical simulations using line-to-line back-EMF, efficiency maps, phase current–torque characteristics, and output power variation. At the nominal operating point of 7000 rpm and 3.5 Nm, the prototype delivered 2.5 kW output power with an experimental efficiency of 90.7%. The deviations between experimental and simulation results were 1.17% for phase current, 0.48% for line-to-line back-EMF, 1.18% for input power, and 1.20% for efficiency. Mechanical static structural finite element analysis indicated a rotor safety factor of 3.61 under the maximum centrifugal loading condition, while the resulting structural deformation remained sufficiently low to avoid adverse effects on air-gap alignment. In addition, the rotor incorporated an adhesive-free, mechanically disassemblable magnet-retention structure, which was mechanically evaluated under centrifugal loading and showed no magnet displacement, structural damage, or bolt-preload loss after testing. Thermal analysis and continuous-load experimental testing showed that the winding temperature remained around 80 °C under passive cooling conditions. Overall, the results demonstrate that the manufactured IPMSM prototype provides consistent electromagnetic performance, adequate mechanical reliability, and thermally safe operation for compact electric vehicle applications. Full article

This study systematically investigates the effects of varying Ni doping levels (1.0–7.0 wt.%) on the microstructure, static magnetic properties, and high-frequency dynamic magnetic performance of Fe-5.5 wt.% Si soft magnetic composites (SMCs). Toroidal core samples were fabricated using powder metallurgy combined with silicone resin coating and high-temperature annealing. The influence of Ni doping on phase composition, morphology, saturation magnetization, coercivity, effective permeability, quality factor, total core loss and its components, and DC bias characteristics was comprehensively evaluated by XRD, SEM, EDS, hysteresis loop testing, and DC bias measurements. The results indicate that an appropriate Ni content (3.0–5.0 wt.%) promotes the formation of α-Fe(Si,Ni) solid solution and (Fe,Ni)₃Si ordered phases, optimizes grain size and structural ordering, enhances saturation magnetization, and reduces coercivity. In contrast, excessive Ni doping (7.0 wt.%) leads to Ni segregation at grain boundaries, forming strong pinning centers that significantly increase coercivity and hysteresis loss. Within the wide frequency range of 1–100 kHz, Ni doping improves the permeability retention under DC bias but reduces the initial effective permeability. Notably, the sample with 5.0 wt.% Ni exhibits the highest quality factor (Q value) across the entire frequency range, demonstrating the best overall performance. This study provides experimental evidence and theoretical guidance for developing high-saturation-resistance, low-loss soft magnetic composites for medium-to-high-frequency applications. Full article

With the pervasive deployment of 5G communication systems and electronic devices, electromagnetic (EM) pollution has emerged as a critical environmental concern. Due to their wide availability, low cost, and ease of acquisition, biomass materials have been widely used in the preparation of electromagnetic wave absorption materials. Compared with traditional in situ impregnation methods, this study first employs chemical reagents to reduce the lignin content within balsa wood, thereby opening more pores and enhancing the loading capacity of iron salts. Subsequently, magnetic Fe₃O₄ particles are synthesized in situ, enabling the fabrication of magnetic wood-based composites. Compared with the non-impregnated pure carbonized samples, the reflection loss value of the samples with magnetic particles increased to −42.37 dB, corresponding to a matching thickness of 1.5 mm. This is much better than the −8.79 dB of the pure carbonized samples, and is attributed to multiple loss mechanisms. In addition, modern physical and chemical analysis instruments such as SEM, TEM, XRD, XPS, and Raman were used to characterize the physical and chemical changes of the materials. Finally, its applications in aerospace and thermal response were identified. Full article

Background: Accurate segmentation of brain tumors from multi-modal magnetic resonance imaging (MRI) is essential for diagnosis, treatment planning, and therapy monitoring. However, this task remains challenging due to tumor heterogeneity, irregular boundaries, and the complex anatomical structure of surrounding tissues. In particular, precise delineation of tumor sub-regions—including whole tumor, tumor core, and enhancing tumor—continues to be a major limitation of existing automated methods. Methods: In this study, we propose a novel hybrid CNN–Transformer framework that integrates local feature extraction with global contextual modeling for improved brain tumor segmentation. The architecture consists of three main components: a dual-pathway encoder for capturing fine-grained and contextual features, a multi-scale feature fusion module based on spatial pyramid pooling with dense connections, and a boundary-aware attention decoder designed to enhance segmentation accuracy around tumor edges. The model utilizes four MRI modalities (T1, T1ce, T2, and FLAIR) to capture complementary tumor characteristics. In addition, a hybrid loss function combining Dice, focal Tversky, and boundary losses is employed to address class imbalance and improve boundary precision. Results: Experimental results on the BraTS 2023 dataset demonstrate superior performance, achieving Dice scores of 92.3%, 88.7%, and 84.5% for whole tumor, tumor core, and enhancing tumor, respectively, while maintaining high computational efficiency. Conclusion: The proposed framework achieves accurate and robust brain tumor segmentation by effectively integrating local and global features, demonstrating its potential for automated multi-modal MRI analysis in clinical practice. Full article

The research utilizes Ansys Maxwell 2024 R2, a 3D Finite Element Analysis (FEA) software, to compare the electromagnetic coil parameters, losses, and efficiency of planar spiral circular, square, and round-cornered square (RCS) coils for wireless power transfer (WPT) systems in electric vehicle (EV) applications. This study focuses on key coil parameters such as self-inductance, mutual inductance, and the coupling coefficient, which are crucial for determining power transfer and system efficiency. While analytical calculations for these parameters are straightforward for air-core transformers, they become complex and inaccurate when ferrite cores are incorporated to improve efficiency. Ansys Maxwell overcomes this challenge by employing a numerical method. Simulation results indicate that RCS coils offer uniform magnetic field distribution and reduced losses, similar to circular coils. They also exhibit better coupling and good misalignment tolerance, akin to square coils. These characteristics suggest that RCS coils are a superior choice for WPT applications. Electro-thermal management (ETM) co-simulation of the RCS coil is performed and analyzed using Ansys Icepak 2024 R2. Furthermore, an Ansys Twin Builder 2024 R2 co-simulation of a double-sided LCL-compensated WPT system, incorporating the reduced-order model of the RCS coil, is performed. Under standardized EV conditions, say 85 kHz, 35 mm, and 50 Ω load, the RCS coil achieves an efficiency of 94.81%. The research also includes loss analysis and misalignment tolerance studies, confirming the superiority of RCS coils. Full article

Synchronous Reluctance Machines (SynRMs) have emerged as a strong candidate for electric vehicle (EV) traction owing to their rare-earth-free construction, robust rotor structure, and competitive efficiency relative to permanent magnet (PM) and induction machines (IMs). Their performance, however, is governed by complex electromagnetic and thermal phenomena—saliency, magnetic saturation, flux-barrier geometry, and temperature-dependent losses—that demand accurate yet computationally tractable modelling. This paper reviews the modelling and design landscape for SynRMs in EV traction, covering analytical approaches (d–q models, magnetic equivalent circuits), numerical methods (finite element analysis), and recent hybrid techniques such as the Enhanced Hybrid Subdomain Method (EHSDM). Rotor geometry optimization, including flux-barrier shaping and saliency-ratio enhancement, is examined alongside coupled magnetic–thermal analysis, an aspect typically treated in isolation in earlier surveys. The review compares the trade-offs of competing techniques across the design workflow—from initial sizing to final verification—and identifies open challenges in reducing computational cost while preserving accuracy. The synthesis is intended to guide motor designers toward modelling choices appropriate to each design stage and to highlight directions for future research in high-performance, rare-earth-free traction motors. Full article

This study proposes an integrated self-aligning-torque energy recovery and DC-bus voltage stabilization strategy for a permanent-magnet synchronous motor (PMSM)-driven steer-by-wire system in new energy vehicles. During the front-wheel return-to-center process, self-aligning torque may provide excess mechanical energy to the steering actuator. Instead of dissipating this energy through a braking resistor, the proposed strategy converts part of the self-aligning-torque-induced mechanical energy into electrical energy and feeds it back to the low-voltage DC bus. To avoid ambiguity in the operating-mode description, this paper distinguishes the standard PMSM torque–speed quadrants from the mechanical stages of the steering process. Regenerative operation is defined according to the condition ($T_e{\omega }_m<0$), corresponding to the second or fourth quadrant of the PMSM torque–speed plane, whereas the return-to-center regenerative stage refers to the self-aligning-torque-dominated stage of the steer-by-wire motion. Based on this definition, an electromechanical energy-flow model is established to describe the transfer path from self-aligning torque to the PMSM and then to the DC bus. Considering that regenerative energy injection may cause DC-bus voltage fluctuation or braking-resistor activation, a single-loop bus-voltage stabilization method based on active disturbance rejection control is developed. A third-order linear extended state observer is adopted to estimate the lumped disturbance caused by self-aligning-torque variation, current coupling, load variation, parameter uncertainty, and inverter loss. The observer bandwidth, controller gains, current limitation, and overvoltage protection mechanisms are further discussed to improve the practical implementability of the proposed control strategy. In addition, an energy-accounting method is introduced to distinguish total steering energy consumption, available self-aligning-torque mechanical energy, gross recovered electrical energy, system losses, net recovered energy, and recovery efficiency. Simulation and experimental results show that the proposed strategy can suppress DC-bus voltage rise, reduce braking-resistor energy dissipation, and achieve measurable steering-actuator-level energy recovery during repeated return-to-center maneuvers. The results verify the feasibility of using self-aligning-torque-induced regenerative energy in PMSM-driven steer-by-wire systems, while the actual vehicle-level energy benefit depends on the driving cycle, low-voltage load demand, battery charging acceptance, and converter efficiency. Full article

Interior permanent magnet synchronous motors have high torque density and a high salient pole effect, combine low-speed high torque with constant-power wide speed regulation, and are increasingly favored by more and more car companies and widely used in electric vehicles. With the development of interior permanent magnet synchronous motors for electric vehicle towards high speed and large capacity, the eddy current loss generated inside the permanent magnet increases rapidly when the magnetic field alternates. Simulation results show that the excessive eddy current loss can raise the permanent magnet temperature of the I2V-type rotor up to 112 °C under rated operating conditions. Such a high temperature far exceeds the stable working temperature range of conventional NdFeB materials and greatly increases the risk of irreversible demagnetization. NdFeB permanent magnet materials have high electrical conductivity but weak heat-resistant capacity, so the temperature rise of permanent magnet is more serious, and even irreversible demagnetization occurs, which is fatal for the safe operation of motors. Therefore, it is necessary to analyze and study the eddy current loss of permanent magnets, explore methods to reduce magnet loss, and design reasonable and efficient cooling systems. Firstly, this paper selects three different rotor topologies as research objects, establishes two-dimensional parameterized finite element analysis models, and analyzes and compares magnet loss and the hysteresis loss, eddy loss, and copper loss of the stator. Secondly, to solve the problem that the I2V-type rotor generates higher magnet loss than the other two structures under all working conditions, magnetic isolation holes are arranged on each rotor pole to optimize the internal magnetic circuit. Simulation analysis results show that this method can effectively reduce magnet loss and stator hysteresis losses. Finally, the temperature of the shaft, magnet and stator winding are studied; aiming at characteristics of high torque density with small size, large torque, and high magnet temperature, a cooling method combining housing cooling and shaft cooling is proposed. Simulation results indicate that the new cooling method can greatly suppress the magnet temperature rise, which reduces the maximum permanent magnet temperature from 112 °C to 80 °C under rated operating conditions and can further improve the torque density and operating reliability of interior permanent magnet synchronous motors. This provides a feasible design reference for high-reliability vehicle interior permanent magnet synchronous motors. Full article

This study used black soldier fly protein (BSFP) as a base material and added 0%, 1%, 2%, 3%, 4%, and 5% of grape seed anthocyanidins (GSAs) to prepare composite gels. Through the combined use of low-field nuclear magnetic resonance, Fourier transform infrared spectroscopy, scanning electron microscopy, and rheometry, the relationships among GSA dosage (0–3%), gel structural properties (secondary protein conformation, water status, and microscopic morphology), and rheological printability were systematically evaluated. It was found that the better GSA content fell within 1–3%, and under this condition the extrusion-type 3D printing performance of the composite gels was significantly enhanced. At a 3% addition amount, the proportion of disordered conformations decreased (random coiling decreased from 15.93% to 15.46%), the ordered structure increased (β-sheet increased from 35.25% to 35.43%), and deformation resistance was enhanced. Low-field nuclear magnetic resonance showed an increase in the proportion of non-flowing water and an increase in physical constraints. Scanning electron microscopy showed a reduction in pore size and a thickening of pore walls, forming a denser 3D network. Rheologic analysis indicated that 3% GSA reached the maximum zero-shear viscosity (η₀) and that the storage modulus (G′) and loss modulus (G″) were higher in the experimental group than those in the control group. Printing fidelity increased from 45.73% in the control group to 60.08% in the 1% group, 62.14% in the 2% group, and 71.05% in the 3% group (p < 0.05). The 3–5% groups (fidelity: 71.05–75.66%) all achieved hollow cylindrical printing without collapse and had excellent self-supporting performance. However, excessive addition (4–5%) caused excess GSA to adsorb onto the protein skeleton surface, reducing the apparent viscosity and damaging the printing performance. Based on all the indicators, the composite gel with 3% GSA achieved the best balance between printability and structural integrity. Our research offers a new idea for using flavonoid compounds to improve the 3D printing performance of insect protein gels. The prepared composite gels can be used as food printing inks and applied to personalized nutrition customization, functional food development, and sustainable protein alternative product fields. Full article

In response to the water loss, shrivelling, and oxidative ageing commonly observed in Golden passion fruit after harvest, this study systematically evaluated the regulatory effects of short-wave ultraviolet (UV-C) treatment. The results showed that UV-C treatment at 3.6 kJ m⁻² significantly curtailed the increases in weight loss and shrivelling index during storage. Low-field nuclear magnetic resonance (LF-NMR) analysis revealed that this treatment effectively maintained the stability of water distribution in fruit tissues by delaying the conversion of free water to bound water. Regarding antioxidant regulation, UV-C treatment significantly increased the activities of key antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR), while promoting the accumulation of non-enzymatic antioxidants, such as total phenols, total flavonoids, and ascorbic acid (AsA). These changes synergistically enhanced reactive oxygen species (ROS)-scavenging capacity, leading to significant reductions in H₂O₂ content and malondialdehyde (MDA) levels, thereby alleviating lipid peroxidation damage to cell membranes. Overall, UV-C treatment effectively maintained cell membrane integrity and regulated water migration through the coordinated regulation of enzymatic and non-enzymatic antioxidant defence systems, thereby delaying passion fruit shrivelling and improving postharvest quality and storage stability. Full article

(Fe/C)/ABS resin electromagnetic metamaterials were fabricated via 3D printing, and the effect of iron salt loading (0, 1, 2, and 3 g) in the Fe/C filler on the microwave absorption performance of the resulting composites was systematically investigated. The results demonstrate that, with increasing iron salt content, the microwave absorption bandwidth of the samples exhibits a trend of initial significant broadening followed by saturation. At an iron salt loading of 1 g, the (Fe/C)/ABS resin composite achieves an effective absorption bandwidth (EAB) of 6.2 GHz at a matching thickness of 10 mm, representing an approximately 48% enhancement over that of the pure C/ABS resin composite (4.2 GHz). The incorporation of iron salts not only endows the material with magnetic loss capability but also promotes the formation of an sp²-hybridized carbon framework within the carbon matrix during Fe/C composite preparation, concurrently introducing abundant defect sites that augment the dielectric loss capacity. Under the synergistic magneto-dielectric loss mechanism, the microwave attenuation coefficient of the material is markedly enhanced, and the effective absorption bandwidth is substantially broadened, all at a filler loading of merely 2.5 wt%. This study elucidates the influence of iron salt loading on the microwave absorption performance of (Fe/C)/ABS resin composites, while the 3D printing-based fabrication approach employed herein offers a promising technical pathway for the development of novel microwave-absorbing materials. Full article

Corn noodles, as a staple food, suffer from poor processing quality and high starch digestibility due to the lack of a gluten network. Magnetically treated Ganoderma lucidum extracellular polysaccharides (MEPSs) possess excellent water-binding and gel-forming properties. This study aimed to investigate the effects of MEPSs at concentrations of 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% on the technological quality and functional properties of corn noodles and to elucidate the underlying mechanisms through rheological, microstructural, and molecular analyses. The results showed that 0.6% MEPSs was the optimal concentration. Adding MEPSs enhanced dough viscoelasticity and water-holding capacity and induced a compact, continuous gel network with increased short-range molecular order and disulfide crosslinks. Consequently, the cooking loss and breaking rate of corn noodles decreased by 24.69% and 46.65%, respectively, while the hardness and springiness improved and cohesiveness was reduced. Functionally, adding 0.6% MEPSs inhibited α-amylase and α-glucosidase, slowing starch hydrolysis and reducing the estimated glycemic index from 76.4 to 72.3. It also significantly enhanced antioxidant activities, including DPPH, ABTS, and hydroxyl radical scavenging, as well as FRAP. In conclusion, MEPS is a natural multifunctional ingredient that simultaneously improves technological quality and confers hypoglycemic and antioxidant benefits to corn noodles, providing an efficient strategy for developing healthier staple foods. Full article

Microscopic magnetic stimulation (MSTI) induces electric fields without direct charge injection and can shape localized field gradients with asymmetric micro-coils. Most demonstrations still rely on external drivers, off-chip hardware, or separated coil validation, so the CMOS integration boundary remains poorly characterized. This work presents a fabricated $2\times 1 {\mathrm{mm}}^2$ $0.18 \mathsf{\mu }\mathrm{m}$ CMOS magnetic-stimulation SoC that co-integrates ASK-compatible command decoding, FSM and register-based parameter control, a programmable current–voltage–current triangular driver, and a bent top-metal micro-coil, and it characterizes the on-chip driver-to-coil path together with a substrate-aware field model. Sensing-load reconstruction confirms command-to-waveform programmability, including duration-window decoding, burst-count control, and polarity reversal, with measured slew targets that give a peak current of $I_{\mathrm{pk}}=3.72$–$21.6 \mathrm{mA}$. A quantitative comparison contrasts the current-mode triangular driver with conventional electrode stimulators, a coil-impedance measurement shows the coil stays resistive across 1 to 10 MHz, and the measured total SoC power is about 41 mW. Substrate-aware simulation at a $15 \mathsf{\mu }\mathrm{m}$ target plane shows that the grounded p-substrate retains $35.1$–$40.5\%$ of the no-substrate peak x-directed field-gradient metric. The prototype establishes this electrical programmability and the substrate-aware gradient-transfer loss as a compact design-margin metric for CMOS-integrated magnetic stimulation. Direct biological activation is not claimed and is left to future in vitro validation. Full article

Hairpin windings are increasingly adopted in permanent magnet (PM) traction machines owing to their high slot fill factor, compact end-winding structure, and suitability for automated manufacturing. However, limited heat dissipation and high copper losses under peak loading and high-frequency operation result in severe thermal constraints, which restrict the power rating of the machine. This paper presents a multi-physics comparison of different winding cooling topologies for a PM machine with hairpin winding, including hollow conductor cooling, end-winding cooling, and cooling channel insertion at slot-bottom, slot-middle, and slot-opening regions. A coupled electromagnetic–thermal model based on the finite element method (FEM), which accounts the heat transfer between different components, is used to analyze temperature distribution, losses, efficiency, loading capacity, and hydraulic requirements. The results show that the position of the cooling channel has great influence on the thermal behavior and electromagnetic performance of the machine under different working conditions. The study emphasizes the strong coupling between cooling design, conductor geometry, AC loss behavior, and efficiency and provides practical design guidelines for selecting appropriate cooling techniques in high-power-density traction machines. Consequently, an improved cooling system results in a reduced amount of PM for the same output power range. Full article