Electromagnetic forming of AA1060 sheet based on mixed forces generated by a three-coil dual-power system.

The electromagnetic force used in electromagnetic forming is mainly divided into attraction and repulsion. Dual-coil attractive electromagnetic forming can be used in the field of sheet pit repair. However, the magnetic field and eddy current generated by the two coils compete with each other, and the energy utilization rate is low. Therefore, a compensation coil is introduced, and an electromagnetic forming scheme of a three-coil dual-power sheet based on mixed force is proposed and verified by simulation. It is found that the three-coil mixed force can effectively improve the competition between the magnetic field and eddy current. The loading of the mixing force is not a simple superposition of attraction and repulsion, but the mutual promotion of the two. The forming displacement of the three-coil mixed force forming scheme is 582% higher than that of the dual-coil attraction forming scheme, and 89% higher than that of the attract first and then repel forming scheme. The forming effect of the three-coil mixing force is related to the number of turns of the compensation coil. The research results can improve the energy utilization rate of electromagnetic forming and provide a new idea for the loading scheme of electromagnetic forming force field.

Magnetically driven capsules with multimodal response and multifunctionality for biomedical applications.

Untethered capsules hold clinical potential for the diagnosis and treatment of gastrointestinal diseases. Although considerable progress has been achieved recently in this field, the constraints imposed by the narrow spatial structure of the capsule and complex gastrointestinal tract environment cause many open-ended problems, such as poor active motion and limited medical functions. In this work, we describe the development of small-scale magnetically driven capsules with a distinct magnetic soft valve made of dual-layer ferromagnetic soft composite films. A core technological advancement achieved is the flexible opening and closing of the magnetic soft valve by using the competitive interactions between magnetic gradient force and magnetic torque, laying the foundation for the functional integration of both drug release and sampling. Meanwhile, we propose a magnetic actuation strategy based on multi-frequency response control and demonstrate that it can achieve effective decoupled regulation of the capsule's global motion and local responses. Finally, through a comprehensive approach encompassing ideal models, animal ex vivo models, and in vivo assessment, we demonstrate the versatility of the developed magnetic capsules and their multiple potential applications in the biomedical field, such as targeted drug delivery and sampling, selective dual-drug release, and light/thermal-assisted therapy.

The Numerical Analysis of Force and Comparison of Pulse Magnet and Electromagnetic Forming Coil.

As an important energy conversion component in electromagnetic-forming technology, the coil is subjected to great internal stress and is easy to break. The geometric structure and winding process of the forming coil draw on the research results of pulsed magnets. However, the two use conditions are different. It is very important to clarify the force difference between the two for the design of the forming coil. In this paper, the numerical model of an aluminum alloy (AA1060-O) is established, and the difference in force between the pulse magnet and forming coil with the same size in time and space under different working conditions is analyzed. A two-dimensional fully coupled finite element model consisting of circuit, magnetic field, and solid mechanics is established and used to determine the key parts of the coil force. It is found that the von Mises stress of the forming coil is greater than that of the pulsed magnet under the same circuit parameters and geometric structure. In the electromagnetic forming of the tube, the glass fiber is subjected to a large stress. In addition, the stress of glass fiber under the condition of tube necking is about 2 times that of pulsed magnet. When the voltage is increased, the failure of the middle part of the glass fiber causes the coil to break. In the electromagnetic forming of the sheet, the coil skeleton is subjected to large stress, and its upper end failure causes the coil to break. Therefore, new design ideas for forming coils under different working conditions are proposed.

Magnetic confinement-enabled membrane reactor for enhanced removal of wide-spectrum contaminants in water: Proof of concept, synergistic decontamination mechanisms, and sustained treatment performance.

Membrane chemical reactors (MCRs) have demonstrated a great potential for simultaneous removal of wide-spectrum pollutants in advanced water treatment. However, current catalyst (re)loading and catalytic reactivity limitations obstruct their practical applications. Herein, as a proof-of-concept, we report a hollow fiber membrane chemical reactor (HF-MCR) with high and sustainable catalytic reactivity, enabled by novel magnetic confinement engineering of the catalysts. Namely, the zerovalent iron (ZVI) nanocatalysts were spatially dispersed and confined to nearly parallel magnetic induction lines, forming forest-like microwire arrays in the membrane lumen. Such arrays exhibited ultrahigh hydrodynamic stability. The HF-MCR integrated sequential membrane separation and Fenton-like catalysis, thus being capable of high and synergistic wide-spectrum decontamination. The membrane separation process completely removed large nanoplastics (NPs) via size exclusion, and thus the subsequent Fenton-like catalysis process enhanced removal efficiency of otherwise permeated bisphenol A (BPA) and phosphate (P) by in situ generated reactive oxygen species (primarily 1O2) and iron (oxyhydr)oxides, respectively. Furthermore, highly dispersed ZVI arrays and their continuous surface depassivation driven by magnetic gradient and hydrodynamic forces conferred abundant accessible catalytic sites (i.e., Fe0 and FeII) to stimulate Fenton-like catalysis. The consequent enhancement of BPA and P removal kinetics was 3-765 and 49-492 folds those in conventional (flow-through or batch) systems, respectively. Periodic ZVI reloading ensured sustained decontamination performance of the HF-MCR. This is the first demonstration of the magnetic confinement engineering that enables efficient and unlimited catalyst (re)loading and sustainable catalytic reactivity in the MCR for water treatment, which is beyond the reach of current approaches.

The Influence of Psychological Safety on Students' Creativity in Project-Based Learning: The Mediating Role of Psychological Empowerment.

Creative-oriented new educational model will shape the direction and appearance of world development. This study focuses on the role of psychological safety and psychological empowerment in improving students' creativity in the context of project-based learning from the perspective of student empowerment. Based on self-determination theory, we propose that psychological safety positively affects students' creativity through psychological empowerment, and fault-tolerant culture plays a positive role in it. In this study, 238 students who participated in project-based learning were randomly selected to conduct a questionnaire survey. The results show that there is a positive correlation between psychological safety and creativity, and psychological empowerment plays an intermediary role in the relationship between them. The fault-tolerant culture enhances the direct influence of psychological safety on psychological empowerment and the indirect influence of psychological safety on creativity. Theoretical and practical implications were also discussed.

Rapid decomposition of diclofenac in a magnetic field enhanced zero-valent iron/EDTA Fenton-like system.

In this study, significant synergistic degradation of antibiotic diclofenac (DCF) was demonstrated in a novel magnetic field (MF) enhanced zero-valent iron (ZVI)/EDTA Fenton-like system. Five operational parameters, namely, initial ZVI loading, pH, EDTA dosage, DCF concentration and reaction temperature, were investigated for their effects on the DCF degradation. OH was identified as the predominant reactive oxygen species for DCF degradation in ZVI/EDTA systems whether in the presence or absence of MF. DCF molecule can be oxidized by OH, attacking via the hydroxylation and substituted dechlorination of the chlorinated aromatic ring, as well as by dehydration between the N atom and the acetoxyl. It could also be directly dechlorinated by ZVI reduction simultaneously. The reaction mechanism and promotional role of MF in the MF/ZVI/EDTA system were proposed. It is suggested that MF mainly alters the heterogeneous ZVI surface-bond reactions and accelerates the surface corrosion depending on the presence of pristine iron oxides layer, but MF does not change the homogeneous iron cycle and the Fenton-like reactions.

Post-assembly magnetization of a 100 kW high speed permanent magnet rotor.

A post-assembly magnetizing fixture has been designed and successfully used to magnetize the rotor of a 100 kW high speed permanent magnet synchronous motor. The rotor is a solid cylinder with outer diameter of 80 mm and total length of 515 mm. The permanent magnet material is samarium-cobalt (Sm2Co17) with saturation magnetizing field of 6 T. The mechanical stability of the magnetizing fixture has been studied as well as the general design methodology. The magnetizing coil is subdivided in order to reduce the electromagnetic force, and the coils are separately reinforced in different ways. The electromagnetic and structural optimization is performed by finite element analysis and verified by experiments.