Static Magnetic Field Research Articles

Design requirements for human UHF magnets from the perspective of MRI scientists

Abstract The highest magnetic field strength for human-sized magnetic resonance imaging (MRI) currently lies at 11.7 tesla. Given the opportunities for enhanced sensitivity and improved data quality at higher static magnetic fields, several initiatives around the world are pursuing the implementation of further human MRI systems at or above 11.7 tesla. In general, members of the MR research community are not experts on magnet technology. However, the magnet is the technological heart of any MR system, and the MRI community is challenging the magnet research and design community to fulfill the current engineering gap in implementing large-bore, highly homogeneous and stabile magnets at field strengths that go beyond the performance capability of niobium-titanium. In this article, we present an overview of magnet design for such systems from the perspective of MR scientists. The underlying motivation and need for higher magnetic fields are briefly introduced, and system design considerations for the magnet as well as for the MRI subsystems such as the gradients, the shimming arrangement, and the radiofrequency hardware are presented. Finally, important limitations to higher magnetic fields from physiological considerations are described, operating under the assumption that any engineering or economic barriers to realizing such systems will be overcome.

Performance of a novel Built-in Static Magnetic Field – Biological Aerated Filter (BSMF–BAF) for treating high-salt textile dyeing wastewater

High-salt textile dyeing wastewater is difficult to treat. Magnetic fields can enhance the biodegradation capacity and extreme environmental adaptabilities of microorganisms. Thus, magnetically enhanced bioreactors are expected to improve the treatment efficiency and stability of high-salt textile dyeing wastewater. Accordingly, a novel Built-in Static Magnetic Field – Biological Aerated Filter (BSMF–BAF) was constructed and investigated for treating actual high-salt textile dyeing wastewater in this study. Two other BAFs packed with traditional and magnetic ceramsite carriers, respectively, were simultaneously operated for comparison. The removal of color, chemical oxygen demand (COD), suspended solid (SS) and acute toxicity were monitored. The activities of key enzymes and microbial community structure were analyzed to reveal possible mechanisms for improving the treatment efficiency of traditional BAF using the BSMF. The results showed that the BSMF–BAF possessed the highest removal efficiencies of color, COD, SS and acute toxicity among the three BAFs. The BSMF induced significant increases in the activities of azoreductase and lignin peroxidase, which were responsible for the degradation of azo compounds in the wastewater and the detoxification of toxic intermediates, respectively. Additionally, the BSMF induced the relative enrichment of potentially effective bacteria and fungi, and it maintained a relatively high abundance of fungi in the microbial community, resulting in a high treatment efficiency.

Nonlinear electrodynamics and its possible connection to relativistic superconductivity: an example

Abstract This work presents an illustrative example suggesting a potential connection between the Heisenberg–Euler (HE) model of nonlinear electrodynamics (NLED) and relativistic superconductivity. Within a cylindrical coordinate system, we derive nonlinear Maxwell’s equations from the HE Lagrangian to the fourth order in the electromagnetic (EM) field. By considering static electric and magnetic fields with Gaussian radial profiles, we compute the corresponding HE current density. In parallel, we explore relativistic type-II superconductivity in analogy with the Ginzburg–Landau (GL) theory. We calculate the vortex-supercurrent density of the condensate and propose a link between this current and the HE current. This connection enables the derivation of the relativistic order parameter state. The problem considered in this article may contribute to the understanding of superconductivity in strong EM environments within the broader framework of NLED.

Effect of static magnetic field on the chemical short-range order of CoCrFeMnNi high-entropy alloy prepared by laser powder bed fusion

Recently, laser powder bed fusion (LPBF) has emerged as a potential technique for manipulating chemical short-range order (CSRO) in high-entropy alloys (HEAs), eliminating the need for homogenization treatment. The application of the magnetic field in LPBF has shown promise in refining the microstructure and optimizing the mechanical properties. However, the precise influence of magnetic field on the CSRO of LPBF-processed HEAs remains inadequately understood. Therefore, in this study, we investigate the impact of the static magnetic field on the CSRO of LPBF-processed HEAs. The findings reveal that the presence of the static magnetic field results in a reduction in CSRO, including the size and area fraction. This behavior can be attributed to the influence of the static magnetic field on the melt flow, which is perturbed by the electromagnetic damping effect and thermos-electromagnetic forces, thereby impeding the free diffusion of atoms and ultimately leading to a decrease in CSRO.

Magnetic field enhanced terahertz emission from metallic nanostructures with response to laser spatial profile distribution

This communication proposes an analytical model that exhibits terahertz (THz) radiation generation from spatially corrugated noble-metal spherical and cylindrical nanoparticles (NPs) placed under the influence of an externally applied static magnetic field. This scheme involves the resonant excitation of THz radiation through the beat-wave of two lasers in the presence of ponderomotive nonlinearities. Effect of magnetic field as well as laser intensity profiles, which include super, cosh, flat-top and ring-shaped Gaussian profiles, have been investigated. The incorporation of the magnetic field induces substantially more dynamic laser-metal coupling and influences the surface plasmon resonance condition associated with electrons of the NPs, thereby leading to stronger THz emission. Our results also demonstrate that the spatial profile of the laser affects the THz output, as it impacts the excitation and dynamics of the NPs. Additionally, we find that both the shape, size and interparticle-separation of NPs play crucial roles in enhancing THz generation. Furthermore, we explore the effects of varying other parameters like electric field strength and beam waist of incident lasers. These findings provide valuable insights for the design and optimization of THz sources based on NP systems, offering new avenues for applications in spectroscopy, imaging, communication and biomedical sciences.

Exploring the effect of exchange coupling in (SrFe9.8Al2La0.2O19)1-x/(Co0.7Zn0.3Fe2O4)x nanocomposites synthesised by sol–gel auto combustion method

Extensive research has been conducted over the last decade to develop permanent magnets utilizing less rare earth materials. Exchange-coupled nanocomposite magnets are a fascinating development in the field of permanent magnets. They involve the combination of hard and soft ferrites, resulting in a unique and evolving magnet. Here we present an in-depth structural, morphological and magnetic characterization of ferrite-based nanostructures obtained through a bottom-up sol−gel approach. The combination of high coercivity of a hard phase SrFe9.8Al2La0.2O19 (SFALO) and high saturation magnetization of a soft phase, Co0.7Zn0.3Fe2O4 (CZFO), allowed us to develop exchange-coupled bi-magnetic nanocomposites by varying the mass percentage (x = 0, 0.1, 0.2, 0.3, 0.4, 1). Thermogravimetric analysis (TGA) up to 1200 °C was used to investigate the material’s thermal properties with the phase formation temperature. Detailed atomic/nano-scale structural characterizations of these nanocomposites were performed by X-ray diffraction and Transmission Electron Microscopy. The average particle size was calculated from the SEM analysis and it was observed that most of the composites with ratio x = 0.1, 0.3 & 0.4 was 145 nm and x = 0.2 was 165 nm. The Switching Field Distribution (SFD) curve revealed the exchange coupling between soft and hard magnetic particles. The findings indicate that the inclusion of a soft magnetic phase has a considerable impact on the exchange coupling between the hard and soft ferrite phases. As the spinel concentration increased, in the composite the saturation magnetization increased from 18 emu/g to 48 emu/g. From the stroner-wholfrathmodel, the decrease in the remanence ratio below 0.5 concludes the crystallites are randomly oriented. The nanocomposite with the ratio x = 0.1 was observed with the high magneto crystalline anisotropy of 2183.23 × 102 (J/m3) and a high energy product (BH)max of 5.5 kJ/m3. The aforementioned features of nanocomposites demonstrate their potential for use in permanent magnet applications.

Magnetical scafford with ROS-scavenging for bone regeneration under static magnetic field

Excessive reactive oxygen species (ROS) and bacterial infection significantly disrupt the microenvironment of tissue regeneration. Magnetic nanoparticles in combination with magnetic fields are emerging strategies to regulate tissue regeneration. In this work, ZnFe2O4 (ZFO) nanoparticles were prepared and subsequently decorated with polydopamine (PDA) and RGD peptide. The modified ZFO nanoparticles were loaded into polylactic-glycolic acid/polycaprolactone (PLGA/PCL) scaffolds as PP-ZFO/PDA-RGD magnetic scaffolds. Physicochemical, anti-ROS, antibacterial and osteogenic properties were evaluated in vitro. Under 30 mT static magnetic field, the PP-ZFO/PDA-RGD scaffold significantly enhanced the expression of ALP, RUNX2, BMP2 and mineralized nodules. It indicated that the magnetic system could promote the attachment, proliferation, differentiation and mineralization of MC3T3-E1 cells. The scaffold showed excellent ROS scavenging ability via the additive effect of ZFO, PDA and RGD. The remarkable antibacterial properties of Zn²⁺ and Fe³⁺ endowed the scaffolds with excellent antibacterial activity against E. coli and S. aureus. These results demonstrate that the PP-ZFO/PDA-RGD based magnetic system is a promising approach for bone regeneration under complex microenvironment.

Whole-Head Noninvasive Brain Signal Measurement System with High Temporal and Spatial Resolution Using Static Magnetic Field Bias to the Brain.

Noninvasive brain signal measurement techniques are crucial for understanding human brain function and brain-machine interface applications. Conventionally, noninvasive brain signal measurement techniques, such as electroencephalography, magnetoencephalography, functional magnetic resonance imaging, and near-infrared spectroscopy, have been developed. However, currently, there is no practical noninvasive technique to measure brain function with high temporal and spatial resolution using one instrument. We developed a novel noninvasive brain signal measurement technique with high temporal and spatial resolution by biasing a static magnetic field emitted from a coil on the head to the brain. In this study, we applied this technique to develop a groundbreaking system for noninvasive whole-head brain function measurement with high spatiotemporal resolution across the entire head. We validated this system by measuring movement-related brain signals evoked by a right index finger extension movement and demonstrated that the proposed system can measure the dynamic activity of brain regions involved in finger movement with high spatiotemporal accuracy over the whole brain.

Biomagnetismo medicinal na hepatite autoimune: um estudo de caso

Autoimmune Hepatitis (AIH) is a chronic and severe inflammatory disease of the liver caused by loss of tolerance to hepato-specific autoantigens, and the identification is made by applying diagnostic scores. It is characterized by an increase in serum aminotransferases - aspartate aminotransferase (AST) and alanine aminotransferase (ALT), immunoglobulin G, autoantibodies, where triggering agents appear that confuse the immune system that recognizes components of some hepatocytes as antigens. In this study, Medicinal Biomagnetism (BM) was applied, which is a treatment method developed by Dr. Isaac Goiz Durán (1941-2021), whose technique consists of applying a pair of medium intensity magnets -1,000 to 7,500 Gauss, with opposite polarities that resonate with each other and aim to depolarize the dysfunction magnetic field called Biomagnetic Pair (BMP). The magnetic resonance generated by the static magnetic fields, identifies and restores the electron spin of the biochemical elements that support the hydrogenion potential (pH) distortion. The objectives os this study were: to investigate whether there was any change in the clinical and laboratory signs of the patient undergoing BM and to investigate the applicability of the technique in her clinical evolution; compare possible changes in saliva pH before and after therapy; observe whether there were changes in liver enzymes during the treatment period; find out whether during the treatment the hepatologist indicated a reduction in the dosage of the medication in view of the clinical/laboratory improvement; and if there was an improvement in symptons. Through the analysis of the medical records, it was observed that the BM tecnique made it possible to improve the clinical/laboratory status of the patient with AIH.

Microscale fiber-integrated vector magnetometer with on-tip field biasing using N - V ensembles in diamond microcrystals

In quantum sensing of magnetic fields, ensembles of nitrogen-vacancy centers in diamond offer high sensitivity, high bandwidth and outstanding spatial resolution while operating in harsh environments. Moreover, the orientation of defect centers along four crystal axes forms an intrinsic coordinate system, enabling vector magnetometry within a single diamond crystal. While most vector magnetometers rely on a known bias magnetic field for full recovery of three-dimensional (3D) field information, employing external 3D Helmholtz coils or permanent magnets results in bulky, laboratory-bound setups, impeding miniaturization of the device. Here, a novel approach is presented that utilizes a fiber-integrated microscale coil at the fiber tip to generate a localized uniaxial magnetic field. The same fiber-tip coil is used in parallel for spin control by combining dc and microwave signals in a bias tee. To implement vector magnetometry using a uniaxial bias field, the orientation of the diamond crystal is preselected and then fully characterized by rotating a static magnetic field in three planes of rotation. The measurement of vector magnetic fields in the full solid angle is demonstrated with a shot-noise-limited sensitivity of 19.4nT/Hz1/2 and microscale spatial resolution while achieving a fiber sensor head cross section of less than 1mm2. Published by the American Physical Society 2024

In-situ suppression of high-frequency magnetic field generated by the electric heater for atomic magnetometers

In this study, an in-situ suppression for the high-frequency magnetic field (HFMF) generated by the electric heater based on the detection of the atomic magnetometer signal is proposed. Specifically, by modeling the response of atomic spin precession signals from an optically pumped atomic magnetometer to the HFMF, the in-situ suppression is achieved by the radio frequency fields produced by coils to compensate the HFMF. The suppression of the HFMF generated by the electric heater is judged based on the amplitude response of the spin precession signal detected at the atomic resonance. Our proposed method is validated through both simulation and experimental results. Before and after in-situ suppression of the HFMF generated by the electric heater, the sensitivity of 13000 nT and 15000 nT static magnetic field within the heating frequency band is measured, resulting in approximately 50% and 60% increases in sensitivity after suppression, respectively.

Decomposition of PFAS and Synthesis of BC8 Super-Diamond: Rotations of Electromagnetic Waves for Novel Chemical Dynamics

A new theory is given for the decomposition of PFAS and the formation of BC8 Super-diamond with 13C isotope by application of RBL’s rotating magnetic field, neutrinos and/or antineutrinos and static magnetic field for stimulating nuclei having nonzero nuclear magnetic moments (NMMs). The induced NMMs are proposed more readily in the 19F of PFAS due to the large mass defect of 19F and the many C-F bonds per molecule. The super-diamond with 13C isotope is reasoned to form with its body center cubic lattice with central 13-carbon atom per cube due to the rotating magnetic field, neutrinos and/or antineutrinos and resulting internal induced sp3 hybridization with more efficiency for the applied external pressure and internal pressure by 13C isotope to be better used to compress the resulting sp3 carbon atoms to BC8 super-diamond. The author invented the use of rotating electromagnetic, neutrino and/or antineutrino and magnetic fields to affect chemical dynamics in 2000-07. The author (RBL) thereby here reports the theory and discovery of unusual and large interactions of highly, energetic dynamical hydrogen bonds with neutrinos and antineutrinos.

Experimental and numerical study on single ice crystal growth of deionized water and 0.9 % NaCl solution under static magnetic field

Ice crystal growth of water and its aqueous solution is the key phenomenon in food freezing. In this research, the effect of static magnetic field (SMF) on single ice crystal growth was investigated combing experiment and simulation. The ice crystal growth of water and NaCl-water solution under 0 - 15 mT SMF intensities were studied. The UV absorbance of water after SMF treatment was measured. Phase field model was adopted to simulate the ice crystal growth. The results show that SMF significantly inhibited the growth rate, while had little effect on the morphology and growth direction of ice crystals. SMF had a certain enhancement effect on the UV absorbance of deionized water. The proposed model could well simulate the ice crystal growth under different SMF intensities. Combining experimental and simulation results, it can be inferred that SMF inhibits ice crystal growth by enhancing original hydrogen bonds and reducing free energy.

A 85Rb transverse modulation magnetometer in the geophysical range based on atomic alignment states

Abstract We have constructed a transverse modulated magnetometer based on spin alignment in a paraffin-coated 85 Rb cell operated in a geophysical magnetic field of 47.1 µT. When an orthogonal driving magnetic field ( x ^ axis) is resonant on the Larmor frequency ( z ^ axis), we have proposed a new method to zero the static residual magnetic fields in the transverse plane and achieved a sensitivity of 1.8 pT Hz − 1 with bandwidth of 200 Hz. The repump light ( F g = 2 → F e = 2 ) redistributes the populations in the ground state, rendering the state | F g = 2 ⟩ dark. This effect significantly amplifies the optical rotation signals nearly fourfold. The numerical solution of the Liouville equation is in good agreement with the experimental results. By using perturbation treatment and employing appropriate approximations, the derived analytical expressions for optical rotation are deduced to succinctly elucidate the dynamics of atomic alignment under parametric modulation. These outcomes could be extended for the advancement of an alignment magnetometer that has been designed to detect a weak magnetic signal in the geophysical range.

Theory of Magnetic Properties in Quantum Electrodynamics Environments: Application to Molecular Aromaticity.

In this work, we present ab initio cavity quantum electrodynamics (QED) methods which include interactions with a static magnetic field and nuclear spin degrees of freedom using different treatments of the quantum electromagnetic field. We derive explicit expressions for QED-HF magnetizability, nuclear shielding, and spin-spin coupling tensors. We apply this theory to explore the influence of the cavity field on the magnetizability of saturated, unsaturated, and aromatic hydrocarbons, showing the effects of different polarization orientations and coupling strengths. We also examine how the cavity affects aromaticity descriptors, such as the nucleus-independent chemical shift and magnetizability exaltation. We employ these descriptors to study the trimerization reaction of acetylene to benzene. We show how the optical cavity induces modifications in the aromatic character of the transition state leading to variations in the activation energy of the reaction. Our findings shed light on the effects induced by the cavity on magnetic properties, especially in the context of aromatic molecules, providing valuable insights into understanding the interplay between the quantum electromagnetic field and molecules.

Solvatochromic Dyes Track a Homeopathic Preparation through Water-Stream Systems in a Program to Control Tick Infestation at a Wild Animal Rehabilitation Center in Brazil.

In 2021, the area of CRAS (Centro de Reabilitação de Animais Selvagens - Wild Animal Rehabilitation Center), located in a state park in Campo Grande City, Mato Grosso do Sul, Brazil, was suffering from a tick infestation affecting wild animals that inhabit the area and humans that visited its trails. Following a formal technical-scientific cooperation agreement between IMASUL, an institute for the environment in Mato Grosso do Sul state, and SIGO Homeopatia, a formulated homeopathic complex (Formula Parques Urbanos, FPU) was designed and prepared specifically to treat the animals. This environmental intervention used specially designed slow-release water biodegradable devices. Tracking the FPU signal in water was necessary to monitor and manage the intervention. Our aims were (1) to evaluate, among six previously standardized solvatochromic dyes, which would serve as a marker for the homeopathic complex under study; and (2) to evaluate whether the chosen solvatochromic dye could map the propagation of the homeopathic complex activity throughout the stream system from water samples harvested at different locations over time. Water samples were harvested from each point at different times, filtered, frozen, and sent to the laboratory, where they were prepared at 1cH potency for analysis using 30% ethanol as the vehicle. Solvatochromic dyes were used to analyze the samples since they alter their absorbance when in contact with homeopathic potencies. Of the six dyes tested, Coumarin 7 was found to be the most suitable for tracking the FPU complex. A static and average unidirectional magnetic field of 2,400 Gauss (240 mT), generated by a neodymium magnet, was applied to the samples immediately before reading. There were significant differences in the delta absorbance of dyes when adding treated/potentized water samples, making it possible to map the propagation of the FPU signal throughout the park over time. The signals were identifiable at the same point 1 minute and 32 days after the insertion of the device into the water. These signals were also identifiable after 75 minutes and 8 days at a point far from the insertion place. Coumarin 7 was the best marker for the homeopathic complex (FPU) used to treat the wild animals living in the park. The microplates/enzyme-linked immunosorbent assay reader method and the application of a magnetic field to samples were shown to be effective in tracing homeopathic signals by changes in dye absorbance (p ≤ 0.02) in a real-life situation, with large volumes of water, involving many environmental variables, and over large distances.

ASSESSMENT OF USING WATER OBTAINED THROUGH EVODROP TECHNOLOGY EXPOSED TO ELECTROMAGNETIC WAVES ON CONCRETE PROPERTIES BASED ON FT-IR AND SEM ANALYSES

Various methods are applied to improve the quality of cement and concrete. Many efforts are made to enhance their quality by introducing additional compounds that can stabilize the chemical bonds between their components. Significant effects on hydrogen bonds under the influence of magnetic and electromagnetic waves have been observed. Results have been published with permanent magnetic fields for water treatment for concrete preparation with magnetic inductions B = 4000, 6000, 6000, 9000, and 9250 Gauss. Electromagnetic (e. m.) treated water has emerged as a promising approach for improving the properties of construction materials.Our investigation concerns the properties of concrete. Concrete is a composite building material mainly consisting of cement, aggregates, water, and various chemical additives. Water was activated with electromagnetic fields from solenoid, ranging from 20 to 40 kHz. The study employs Fourier Transform Infrared (FT-IR) spectroscopy analysis and the Scanning Electron Microscope (SEM) method. The experiments were performed on samples and control samples. The control samples were obtained with water before activation with EM fields. Treating the water in concrete preparation with electromagnetic fields leads to greater mixture homogeneity. SEM images substantiate this outcome. The FT-IR peaks are linked to heightened chemical reactivity from improved water parameters attributed to the treatment with the EVOdrop device.

Magnetic-Nanorod-Mediated Nanowarming with Uniform and Rate-Regulated Heating.

Rewarming cryopreserved samples requires fast heating to avoid devitrification, a challenge previously attempted by magnetic nanoparticle-mediated hyperthermia. Here, we introduce Fe3O4@SiO2 nanorods as the heating elements to manipulate the heating profile to ensure safe rewarming and address the issue of uneven heating due to inhomogeneous particle distribution. The magnetic anisotropy of the nanorods allows their prealignment in the cryoprotective agent (CPA) during cooling and promotes subsequent rapid rewarming in an alternating magnetic field with the same orientation to prevent devitrification. More importantly, applying an orthogonal static magnetic field at a later stage could decelerate heating, effectively mitigating local overheating and reducing CPA toxicity. Furthermore, this orientational configuration offers more substantial heating deceleration in areas of initially higher heating rates, therefore reducing temperature variations across the sample. The efficacy of this method in regulating heating rate and improving rewarming uniformity has been validated using both gel and porcine artery models.

Transverse magnetic field effects on diamond quantum sensor for EV battery monitor

Key implementation points for achieving full accuracy in simultaneous temperature and magnetic field measurement and linearity when applying diamond quantum sensors to electric vehicle (EV) battery monitors were investigated. Both the static and busbar current magnetic field are required to be aligned to the NV-axis. If misalignment should exist, the resonance frequency midpoint move in the direction opposite to the temperature change under a large busbar current due to the transverse magnetic field effect. Misalignment could be quantified with an accuracy of ±1° by analysing the resonance frequency midpoint change under a current of ±1,000 A. The transverse magnetic field effects compensation estimated from misalignment, confirmed that the resonance frequency midpoint changed consistently with temperature changes. Furthermore, linearity over a wide dynamic range also improved. Moreover, it will contribute to accurate alignment of the two sensors for differential detection to eliminate external noise as common mode. These are expected to expand the application of diamond sensors for high-precision measurement in a wide dynamic range.

Dust–ion–acoustic damped solitary waves and shocks in laboratory and Saturn's E-ring magnetized nonthermal dusty plasmas with anisotropic ion pressure and dust-charge fluctuation

We study the oblique propagation of weakly nonlinear dust–ion–acoustic (DIA) solitary waves (SWs) and shocks in collisional magnetized nonthermal dusty plasmas that are relevant in laboratory and space (Saturn's E-ring) environments. We consider plasmas to be composed of q-nonextensive hot electrons, thermal positive ions, and immobile negatively charged dust grains immersed in a static magnetic field and take into account the effects of ion creation (source), ion loss (sink), ion–neutral and ion–dust collisions, anisotropic ion pressure, and dust-charge fluctuations on the evolution of small-amplitude SWs and shocks. The ion–neutral collision enhancement equilibrium dust-charge number is self-consistently determined using Newton–Raphson method. We found that in laboratory dusty plasmas with adiabatic dust-charge variation [i.e., when the dust charging frequency (νch) is much higher than the dust–plasma oscillation frequency (ωpd)], the DIA solitary waves (DIASWs) get damped by the effects of the ion–dust and ion–neutral collisions, whereas the ion creation and ion loss lead to the amplification of solitary waves, and they appear as only compressive types with positive potential. On the other hand, in Saturn's E-ring plasmas, where the collisional and ion creation or ion loss effects are insignificant, the non-adiabaticity of dust-charge variation can give rise to the evolution of either damped DIASWs or DIA shocks, depending on the smallness of the ratios νch/ωpd or ωpd/νch, respectively. Furthermore, two critical values of the nonextensive parameter q exist, below (or above) which, the DIASWs and shocks can appear as rarefactive (or compressive) types. The characteristics of DIASWs and shocks are also analyzed numerically for parameters relevant to the laboratory and Saturn's E-ring plasmas.