Application Of Magnetic Field Research Articles

Effect of magnetized water irrigation on Cd subcellular allocation and chemical forms in leaves of Festuca arundinacea during phytoremediation

The application of an external magnetic field has been shown to improve the Cd phytoremediation efficiency of F. arundinacea by leaf harvesting. However, the influencing mechanisms of the promoting effect have not yet been revealed. This study evaluated variations in the Cd subcellular allocation and fractions in various F. arundinacea leaves, with or without magnetized water irrigation. Over 50 % of the metal were sequestered within the cell wall in all tissues under all treatments, indicating that cell wall binding was a critical detoxification pathway for Cd. After magnetized water treatment, the metal stored in the cytoplasm of roots raised from 33.1 % to 45.3 %, and the quantity of soluble Cd in plant roots enhanced from 53.4 % to 59.0 %. The findings suggested that magnetized water mobilized Cd in the roots, and thus drove it into the leaves. In addition, the proportion of Cd in the organelles, and the concentration of ethanol-extracted Cd in emerging leaves, decreased by 13.0 % and 47.1 %, respectively, after magnetized water treatment. These results explained why an external field improved the phytoextraction effect of the plant through leaf harvesting.

Magnetically Induced Near-Infrared Circularly Polarized Electroluminescence from an Achiral Perovskite Light-Emitting Diode

Circularly polarized electroluminescent devices are conventionally fabricated by incorporating an optically active chiral luminophore into their emission layer. Herein, we developed a circularly polarized perovskite light-emitting diode (PeLED) system with an optically inactive perovskite luminophore that can emit near-infrared circularly polarized electroluminescence (CPEL) upon application of an external magnetic field. The magnitude of the magnetic CPEL (gMCPEL) was in the order of 10−3 in the near-infrared wavelength range of 771–773 nm. Although the Pb perovskite quantum dots were achiral, the rotation direction of the CPEL of the magnetic circularly polarized PeLED system was successfully reversed by switching the Faraday geometry of the applied magnetic field. The use of achiral luminophores exhibiting magnetic-field-induced CPEL represents a new approach for the development of circularly polarized electroluminescent devices.

Magnetic Field Effect on Photocatalytic Dye Degradation: A Review

AbstractIn the present day, photocatalysis has become the primary and most promising technology to generate renewable energy and degrade environmental pollutants. Remarkable efforts have been made to improve photocatalytic efficiency. Among these, introducing an external magnetic field is considered a promising strategy to boost photocatalytic performance. This review explores the dynamic realm of improving photocatalytic efficiency, with a particular emphasis on the strategic integration of external magnetic fields. Examining recent breakthroughs, we reviewed the influence of magnetic fields on diverse catalyst materials, including both magnetic and nonmagnetic variants, 2D materials, and semiconductors. Comprehensive coverage is provided on the mechanisms governing photocatalytic dye degradation, materials utilized for catalysis, and the profound impact of magnetic fields on enhancing reaction kinetics. This review also focuses on recent advances in the application and effect of magnetic fields in the magnetic and nonmagnetic catalysts towards dye degradation. This review provides a forward‐looking view, highlighting the potential of magnetic field‐enhanced photocatalysis to play a central role in sustainable energy and environmental management.

Enhancing thermal stability of optimal magnetization reversal in nanoparticles

Energy-efficient switching of nanoscale magnets requires application of a time-varying magnetic field characterized by microwave frequency. At finite temperatures, even weak thermal fluctuations induce perturbations in the magnetization that can accumulate in time, disrupt the phase locking between the magnetization and the applied field, and eventually compromise magnetization switching. It is demonstrated here that the magnetization reversal is mostly disturbed by unstable perturbations arising in a certain domain of the configuration space of a nanomagnet. The instabilities can be suppressed and the probability of magnetization switching enhanced by applying an additional stimulus such as a weak longitudinal magnetic field that ensures bounded dynamics of the perturbations. Application of the stabilizing longitudinal field to a uniaxial nanomagnet makes it possible to reach a desired probability of magnetization switching even at elevated temperatures. The principle of suppressing instabilities provides a general approach to enhancing thermal stability of magnetization dynamics. Published by the American Physical Society 2024

Barkhausen Noise as A Magnetic Nondestructive Testing Technique

Magnetic Barkhausen Noise (MBN) is a magnetic-based non-destructive electromagnetic testing method. Due to the electromagnetic working principle of MBN, it can be used for ferromagnetic materials, which consist of small magnetic fields discredited by domain walls and oriented in various directions. In an external magnetic field application, the fields turn to the magnetic direction, and the domain walls move and cause magnetic flux jumps. The jumps are named Barkhausen Noise (BN). The domain wall movements are sometimes pushed down by microstructure, composition, and defects. As the magnetic domain walls break away from the pinning sites produce MBN signal. MBN can be used for different material properties such as microstructure, composition, residual stress, and hardness. The paper's purpose is to analyze MBN as an improved NDT, clarify the relationship between material properties and MBN profile, and introduce MBN's applications and test equipment of MBN.

3D and 4D Printing of PETG-ABS-Fe3O4 Nanocomposites with Supreme Remotely Driven Magneto-Thermal Shape-Memory Performance.

This study introduces novel PETG-ABS-Fe3O4 nanocomposites that offer impressive 3D- and 4D-printing capabilities. These nanocomposites can be remotely stimulated through the application of a temperature-induced magnetic field. A direct granule-based FDM printer equipped with a pneumatic system to control the output melt flow is utilized to print the composites. This addresses challenges associated with using a high weight percentage of nanoparticles and the lack of control over geometry when producing precise and continuous filaments. SEM results showed that the interface of the matrix was smooth and uniform, and the increase in nanoparticles weakened the interface of the printed layers. The ultimate tensile strength (UTS) increased from 25.98 MPa for the pure PETG-ABS sample to 26.3 MPa and 27.05 MPa for the 10% and 15% Fe3O4 nanocomposites, respectively. This increase in tensile strength was accompanied by a decrease in elongation from 15.15% to 13.94% and 12.78%. The results of the shape-memory performance reveal that adding iron oxide not only enables indirect and remote recovery but also improves the shape-memory effect. Improving heat transfer and strengthening the elastic component can increase the rate and amount of shape recovery. Nanocomposites containing 20% iron oxide demonstrate superior shape-memory performance when subjected to direct heat stimulation and a magnetic field, despite exhibiting low print quality and poor tensile strength. Smart nanocomposites with magnetic remote-control capabilities provide opportunities for 4D printing in diverse industries, particularly in medicine, where rapid speed and remote control are essential for minimally invasive procedures.

Magnetically Controlled Strategies for Enhanced Tissue Vascularization

AbstractTissue vascularization plays a critical role in the regeneration and repair of damaged tissues. However, in certain instances of tissue injury, the pace and effectiveness of vascularization can be limited. Innovative strategies leveraging magnetic fields and magnetic nanoparticles (MNPs) are devised to enhance the efficacy of tissue vascularization. This review explores the potential of magnetic field‐assisted strategies in augmenting tissue vascularization and repair. Direct application of static or dynamic magnetic fields, alone or in combination with MNPs, offers a means to modulate cellular behaviors and gene expression, thereby promoting angiogenesis and tissue regeneration. Techniques such as cell labeling, gene delivery using MNPs, and magnetic targeting have shown promise in efficiently repairing various ischemic tissue injuries by enhancing tissue vascularization. These strategies have broad applications in bone and skin tissue regeneration, limb ischemia treatment, myocardial injury treatment, and diabetic wound therapy. By summarizing recent advancements in magnetically controlled strategies, this review aims to shed light on their future prospects in tissue regeneration and clinical treatment.

Dichotomous dynamics of magnetic monopole fluids

A recent advance in the study of emergent magnetic monopoles was the discovery that monopole motion is restricted to dynamical fractal trajectories [J. N. Hallén et al., Science 378, 1218 (2022)], thus explaining the characteristics of magnetic monopole noise spectra [R. Dusad et al., Nature 571, 234 (2019); A. M. Samarakoon et al., Proc. Natl. Acad. Sci. U.S.A. 119, e2117453119 (2022)]. Here, we apply this novel theory to explore the dynamics of field-driven monopole currents, finding them composed of two quite distinct transport processes: initially swift fractal rearrangements of local monopole configurations followed by conventional monopole diffusion. This theory also predicts a characteristic frequency dependence of the dissipative loss angle for AC field-driven currents. To explore these novel perspectives on monopole transport, we introduce simultaneous monopole current control and measurement techniques using SQUID-based monopole current sensors. For the canonical material Dy2Ti2O7, we measure [Formula: see text], the time dependence of magnetic flux threading the sample when a net monopole current [Formula: see text] is generated by applying an external magnetic field [Formula: see text] These experiments find a sharp dichotomy of monopole currents, separated by their distinct relaxation time constants before and after t ~[Formula: see text] from monopole current initiation. Application of sinusoidal magnetic fields [Formula: see text] generates oscillating monopole currents whose loss angle [Formula: see text] exhibits a characteristic transition at frequency [Formula: see text] over the same temperature range. Finally, the magnetic noise power is also dichotomic, diminishing sharply after t ~[Formula: see text]. This complex phenomenology represents an unprecedented form of dynamical heterogeneity generated by the interplay of fractionalization and local spin configurational symmetry.

Cu(II)-Ln(III) (Ln = Gd, Tb and Dy) complexes of an unsymmetrical N2O3 donor ligand: field induced SMM behaviour of Cu(II)-Tb(III) complexes.

Three new hetero-metallic CuII-LnIII complexes [(CuL)Gd(NO3)3(CH3OH)]n (1), [(CuL)Tb(NO3)3(H2O)]·[CuL] (2) and [(CuL)Dy(NO3)3(H2O)]·[CuL] (3) have been synthesized using a mono-nuclear Cu(II) complex, [CuL], of an unsymmetrically di-condensed N2O3 donor Schiff base ligand, N-(3-methoxysalicylidene)-N-(salicylidene)-1,2-ethylenediamine (H2L). Single crystal X-ray crystallography revealed that complex 1 is a nitrate bridged 1D chain of dinuclear Cu(II)-Gd(III) units whereas in 2 and 3, the dinuclear Cu(II)-Ln(III) units are co-crystallized with a [CuL] unit. The Ln(III) centers are nine coordinated with the geometry of a spherical capped square antiprism for Gd and spherical tricapped trigonal prism for Tb and Dy. The geometry of the Cu(II) center is distorted octahedral for complex 1 and distorted square planar for complexes 2 and 3. Temperature-dependent molar magnetic susceptibility measurements in 1-3 revealed the presence of overall ferromagnetic coupling between the Cu(II) and Ln(III) centers. Notably, field induced single-molecule magnet behavior was witnessed in the Tb(III) derivative (2). The ab initio calculations indicated that upon application of an external magnetic field, the tunneling in the ground state of complex 2 gets reduced and thereby field-induced SMM behaviour is observed. Besides, in the case of complex 1, BS-DFT calculations were carried out to gain further insights into the magnetic exchange coupling interactions between the Cu(II) and Gd(III) centers.

Application of Induction Melting and Constant Magnetic Field to Influence the Redistribution of Components with Different Magnetic Properties in Alloy Grains Based on Al–Cu–REM

Application of Induction Melting and Constant Magnetic Field to Influence the Redistribution of Components with Different Magnetic Properties in Alloy Grains Based on Al–Cu–REM

Modelling the mechanics of 32 T REBCO superconductor magnet using numerical simulation

Abstract High temperature REBCO superconducting tapes are very promising for high-field
magnets. With high magnetic field application there are high electro-mechanical forces, and thus
concern for mechanical damage. Due to the presence of large screening currents and composite
structure of the tape, the mechanical design of these magnets are not straight forward. In addition,
many contemporary designs use insulated winding. In this work we develop a novel two-dimensional
axisymmetric finite element tool programmed in MATLAB that assumes the displacement field within
linear elastic range. The stack of pancakes and a large number of REBCO tape turns are approximated
as an an-isotropic bulk hollow cylinder. Our results agree with uni-axial stress experiments in
literature, validating the bulk approximation. Here, we study the following configuration. The
current is first ramp up to below the critical current and we calculate the screening currents and the
forces that they cause using the MEMEP model. This electromagnetic model can now take insulated
magnets into account. As a case study 32 T REBCO superconductor magnet is simulated numerically.
We have done complete mechanical analysis of the magnet by including the axial and shear mechanical
quantities for each pancake unlike previous work where only radial and circumferential quantities are
focused. Effect on mechanical quantities without screening current is also calculated and compared.
It is shown that including screening current induced field strongly affect the mechanical quantities,
specially the shear stress. The latter might be the critical quantity for certain magnet configurations.
Additionally, in order to overcome high stresses, a stiff over banding of different material is considered
and numerically modelled which significantly reduces the mechanical stresses. The FE based model
developed is efficient to calculate the mechanical behaviour of any general superconductor magnet
and its devices.

Pulsed electromagnetic field-assisted reduced graphene oxide composite 3D printed nerve scaffold promotes sciatic nerve regeneration in rats

Peripheral nerve injuries can lead to sensory or motor deficits that have a serious impact on a patient’s mental health and quality of life. Nevertheless, it remains a major clinical challenge to develop functional nerve conduits as an alternative to autologous grafts. We applied reduced graphene oxide (rGO) as a bioactive conductive material to impart electrophysiological properties to a 3D printed scaffold and the application of a pulsed magnetic field to excite the formation of microcurrents and induce nerve regeneration. In vitro studies showed that the nerve scaffold and the pulsed magnetic field made no effect on cell survival, increased S-100β protein expression, enhanced cell adhesion, and increased the expression level of nerve regeneration-related mRNAs. In vivo experiments suggested that the protocol was effective in promoting nerve regeneration, resulting in functional recovery of sciatic nerves in rats, when they were damaged close to that of the autologous nerve graft, and increased expression of S-100β, NF200, and GAP43. These results indicate that rGO composite nerve scaffolds combined with pulsed magnetic field stimulation have great potential for peripheral nerve rehabilitation.

Application of magnetism in tissue regeneration: Recent progress and future prospects

Abstract Tissue regeneration is a hot topic in the field of biomedical research in this century. Material composition, surface topology, light, ultrasonic, electric field and magnetic fields (MFs) all have important effects on the regeneration process. Among them, MFs can provide nearly non-invasive signal transmission within biological tissues, and magnetic materials can convert MFs into a series of signals related to biological processes, such as mechanical force, magnetic heat, drug release, etc By adjusting the MFs and magnetic materials, desired cellular or molecular-level responses can be achieved to promote better tissue regeneration. This review summarizes the definition, classification, and latest progress of MFs and magnetic materials in tissue engineering. It also explores the differences and potential applications of MFs in different tissue cells, aiming to connect the applications of magnetism in various subfields of tissue engineering and provide new insights for the use of magnetism in tissue regeneration.

Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets

Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets

Magnetotransport properties of BiSe whiskers

Doped Bi2Se3 superconductors, such as CuxBi2Se3, SrxBi2Se3, NbxBi2Se3 are shown to be nematic superconductors in addition to the observed topological superconductivity. Recently it was found superconductivity in PdxBi2Se3 whiskers. The superconductivity has a residual character and probably exists on the whisker surface. The present paper deals with checking a possible nematicity existing in PdxBi2Se3 whiskers. The suppression of superconductivity was measured in the magnetic fields with induction up to 1.5 T. It was found the dependency of upper critical fields on the angle of magnetic field application. The dependency is explained in the framework of Ginzburg–Landau model and described by rather small anisotropy parameter 1.2. Besides blurring of temperature Curie near 5.3 K was observed of about 0.5 K that additionally confirmed the nematicity in PdxBi2Se3 whiskers. The rather high Curie temperature as well as nematicity existing is probably connected with strong spin–orbit interaction (SOI) of the charge carriers in the whiskers which stabilizing the superconductive state. When the temperature exceeds T c weak antilocalization of charge carriers is observed in the whisker magnetoresistance.

Evidence of a significant full tripartite entanglement in a mixed spin-(1/2,1) Heisenberg tetramer

We rigorously analyze the full tripartite entanglement of a mixed spin-(1/2,1) Heisenberg tetramer in the presence of an external magnetic field. The tetramer consists of two mixed spin-(1/2,1) dimers arranged to form a square plaquette, with distinct exchange couplings J and J1 between spins from the same and different dimers, respectively. The full tripartite entanglement is classified according to the tripartite negativity NABC defined as a geometric mean of all possible bipartite negativities NA|BC, NB|AC, and NC|AB, when the degrees of freedom of the fourth spin D of the tetrapartite system ABCD are traced out. We demonstrate that for J1/J>1, both trimeric subsystems 1/2-1-1 and 1/2-1/2-1 exhibit tripartite entanglement mediated through the central spin. This entanglement becomes more robust upon the application of an external magnetic field. The opposite limit J1/J<1 leads to the spontaneous emergence of full tripartite entanglement solely within the subsystem 1/2-1-1. However, the increasing magnetic field swiftly disrupts the three-particle correlation across the relevant ground-state phase boundary. Additionally, we identify that in the isotropic limit J1/J=1, the ground-state degeneracy significantly reduces the strength of full tripartite entanglement and favors nontrivial subtypes of full nonseparable states with none or just one spin-dimer entanglement. Finally, we discuss in detail the thermal stability of all fully tripartite nonseparable states.

Targeted Rapamycin Delivery via Magnetic Nanoparticles to Address Stenosis in a 3D Bioprinted in Vitro Model of Pulmonary Veins.

Vascular cell overgrowth and lumen size reduction in pulmonary vein stenosis (PVS) can result in elevated PV pressure, pulmonary hypertension, cardiac failure, and death. Administration of chemotherapies such as rapamycin have shown promise by inhibiting the vascular cell proliferation; yet clinical success is limited due to complications such as restenosis and off-target effects. The lack of in vitro models to recapitulate the complex pathophysiology of PVS has hindered the identification of disease mechanisms and therapies. This study integrated 3D bioprinting, functional nanoparticles, and perfusion bioreactors to develop a novel in vitro model of PVS. Bioprinted bifurcated PV constructs are seeded with endothelial cells (ECs) and perfused, demonstrating the formation of a uniform and viable endothelium. Computational modeling identified the bifurcation point at high risk of EC overgrowth. Application of an external magnetic field enabled targeting of the rapamycin-loaded superparamagnetic iron oxide nanoparticles at the bifurcation site, leading to a significant reduction in EC proliferation with no adverse side effects. These results establish a 3D bioprinted in vitro model to study PV homeostasis and diseases, offering the potential for increased throughput, tunability, and patient specificity, to test new or more effective therapies for PVS and other vascular diseases.

Magnetic field effects on the thermomechanical vibration behavior of functionally graded biocompatible material sandwich nanobeams

This study focuses on modeling and analyzing the thermomechanical vibration behavior of sandwich nanobeams made from biocompatible zirconia and Ti-6Al-4V materials. The sandwich nanobeam is composed of the materials mentioned earlier, featuring a porous structure in the core layer. The sandwich nanobeam experiences significant thermal load and is subjected to a horizontal external electromagnetic field. The equations of motion for the sandwich nanobeam were derived through the application of the sinusoidal high-order shear stress theorem and the constitutive equation based on nonlocal strain gradient elasticity. The equations were converted into equations of motion using Hamilton’s principle, incorporating the thermal load and the Lorentz force generated in the electromagnetic field, and solved using the Navier method. Analyses were conducted on the thermomechanical vibration behavior of the sandwich nanoplate, taking into consideration the properties of the sandwich layers, the impact of temperature, and the intensity of the applied horizontal magnetic field. The impact of the porous core layer in the sandwich nanoplate on the porosity volume ratio and porosity distribution function in thermomechanical behavior has been established. Research has demonstrated that the application of an external magnetic field can effectively mitigate the adverse impacts of thermal loads caused by high temperatures.

Spin polarization in Fe-doped CsPbBr3 perovskite nanocrystals for enhancing photocatalytic CO2 reduction

Spin manipulation offers an effective strategy to enhance photocatalytic activity in metal halide perovskites by suppressing the recombination of photo-excited electrons. However, the scope of the magnetic dopant inducing spin polarization is still limited. Here, we introduce synergetic strategies to polarize the spin in photo-excited electrons and boost their photocatalytic activity for CO2 reduction. We dope iron cation (Fe2+) into CsPbBr3 perovskite nanocrystals (PNCs). Fe ions induce paramagnetism, fostering spin polarization within the Fe-doped CsPbBr3 PNCs (Fe-CsPbBr3 PNCs) under magnetic fields. The magnetic compositions in PNC tend to stabilize the spin polarized electrons within the PNC, mitigate the recombination of photo-excited electrons and enhance the redox reaction for photocatalytic CO2 reduction. The synergistic effects of magnetic element doping and the application of magnetic fields resulted in a photocatalytic CO2 reduction of 133.04 g−1, which is 1.68-fold increase compared to the Fe-PNC without a magnetic field. This work provides a simple and environmentally friendly approach to CO2 reduction based on PNCs.

Structure-property studies of a four coordinate niobium(IV) amide

The preparation, structure, and magnetic properties of Nb[N(Dipp)TMS]2Cl2 (1) are described. The paramagnetic complex is obtained via treatment of NbCl4(THF)2 with two equivalents of Li[N(Dipp)TMS]. Magnetic studies indicate NbIV (S = ½) ions are present and that slow frequency-dependent magnetization relaxation dynamics are operative below ca. 25 K, under application of non-zero magnetic fields. The relaxation dynamics appear to proceed via a Raman pathway.