Effect Of Pulsed Magnetic Field Research Articles

Pulsed Magnetic Field Treatment Effects on Undissolved Carbides in Continuous Casting Billets of GCr15 Bearing Steel

The study investigates the effect of pulsed magnetic fields on undissolved carbides in high-carbon chromium bearing steel GCr15 billets. The billets were subjected to heat treatment at 950 °C, with a pulsed magnetic field of varying durations applied during the process. The influence of the pulsed magnetic field on the distribution of undissolved carbides within the billets was investigated, and the thermodynamic and kinetic mechanisms of undissolved carbides dissolution were explored. The results indicate that the area percentage of undissolved carbides in the microstructure decreases from 1.68% to 0.06% after applying a pulsed magnetic field for 10 min, and the size of undissolved carbides decreases from 17.5 μm to 4.9 μm. When a pulsed magnetic field is applied for 30 min, all undissolved carbides dissolve. The statistics demonstrate that the average size of undissolved carbides is reduced from 14.19 μm to 0.63 μm, with a reduction percentage reaching 96%. Over the same duration, the number density of the undissolved carbides decreases from (0.19~0.55)/mm2 to (0.03~0.1)/mm2, and the percentage area of the undissolved carbides decreases from (1.26~1.68)% to (0~0.02)%. Thermodynamically, applying a pulsed magnetic field lowers the dissolution energy barrier of undissolved carbides and modifies their transformation temperature. Kinetically, the rate of alloy element diffusion is enhanced by increasing the frequency of atomic jumps. This research aims to provide new insights into enhancing the contact fatigue life of bearing steel, increasing the proportion of special steel, and optimizing the steel deep-processing process.

Anti-inflammatory effects of pulsed magnetic field on the immune system

When an inflammatory response occurs in the body, primary immune cells, such as macrophages, phagocytize and present antigens, and secondary immune cells, such as T cells, produce antibodies against the presented antigens to prevent infection in the body. Abnormalities in the immune system releases pro-inflammatory cytokines such as TNF-α and IL-6, leading to rheumatoid arthritis and sepsis. This study aimed to confirm the change in inflammatory activity across innate immunity and acquired immunity while investigating the effects of pulsed magnetic field (PMF) on the immune system to regulate excessive inflammation. Raw 264.7 and EL4 cells were co-cultured in a DMEM medium using permeable cell culture inserts and inflammation was induced using LPS. Our PMF stimulator has the maximum intensity of 4700 G at a transition time of 136 μs with pulse intervals of 1 Hz. In order to confirm anti-inflammatory effects of PMF, the level of IL-6, pH and mitochondrial respiration rate (MRR) were measured using ELISA, pH meter and MTT assay, respectively. It was observed in vitro that inflammation-induced macrophages induce activation of T cells, as evidenced by the faster acidification in pH, increased IL-6 expression, and enhanced MRR, compared to T cells. But after PMF stimulation, pH levels improved, the concentration of IL-6 reduced, and MRR decreased in both macrophages and T-cells, which indicates inflammation relief. Our results show that macrophages, the primary immune cells, are first involved in the inflammatory response and recovery and influence T cells, the secondary immune cells. Therefore PMF stimulus is thought to affect the immune system of the human body by balancing the activation and suppression of immune cells and improve anti-inflammation. For clinical use, non-invasive PMF can be developed as a medical devices modulating immune system with optimizing the PMF conditions such as pulse shape, duration, or repetition rate.

Mass Spectrometric Identification of Metabolites after Magnetic-Pulse Treatment of Infected Pyrus communis L. Microplants

The major goal of this study is to create a venue for further work on the effect of pulsed magnetic fields on plant metabolism. It deals with metabolite synthesis in the aforementioned conditions in microplants of Pyrus communis L. So far, there have been glimpses into the governing factors of plant biochemistry in vivo, and low-frequency pulsed magnestatic fields have been shown to induce additional electric currents in plant tissues, thus perturbing the value of cell membrane potential and causing the biosynthesis of new metabolites. In this study, sixty-seven metabolites synthesized in microplants within 3–72 h after treatment were identified and annotated. In total, thirty-one metabolites were produced. Magnetic-pulse treatment caused an 8.75-fold increase in the concentration of chlorogenic acid (RT = 8.33 ± 0.0197 min) in tissues and the perturbation of phenolic composition. Aucubin, which has antiviral and antistress biological activity, was identified as well. This study sheds light on the effect of magnetic fields on the biochemistry of low-molecular-weight metabolites of pear plants in vitro, thus providing in-depth metabolite analysis under optimized synthetic conditions. This study utilized high-resolution gas chromatography-mass spectrometry, metabolomics methods, stochastic dynamics mass spectrometry, quantum chemistry, and chemometrics, respectively. Stochastic dynamics uses the relationships between measurands and molecular structures of silylated carbohydrates, showing virtually identical mass spectra and comparable chemometrics parameters.

Application of high-intensity pulsed magnetotherapy in the medical rehabilitation of children with degree scoliose (methodological recommendations)

In the medical rehabilitation of children with scoliosis, a fairly wide range of physiotherapy technologies (sinusoidal modulated currents, interference currents, laser therapy, combined use of hypobarotherapy and electrical muscle stimulation, low-intensity magnetic therapy, biofeedback therapy) are used. At the same time, the search for the most effective methods of physiotherapy aimed at stimulating muscle tone, local blood circulation and metabolic and trophic processes in bone and muscle tissues continues. One of the promising methods is high-intensity pulsed magnetic therapy (HIMT), which is a therapeutic effect of a pulsed magnetic field (PMF) with a pulse repetition rate of about 0.5 Hz, a duration not exceeding several milliseconds and an amplitude reaching 1500 mT or more on the working surface of the inductor. The guidelines substantiate the use of this method in the medical rehabilitation of children with scoliosis of the II degree on the basis of the revealed favorable effect of a high-intensity pulsed magnetic field on the dynamics of the orthopedic status, strength endurance of the trunk muscles, cardio-respiratory parameters and microcirculation in children with scoliosis of the II degree. The effectiveness, necessity and expediency of including high-intensity pulsed magnetic therapy in the program of medical rehabilitation of children with II degree scoliosis has been proved. The methodological recommendations are addressed to traumatologists — orthopedists, physiotherapists, physical therapy doctors, physical and rehabilitation medicine doctors, reflexologists, pediatricians, and other specialists of medical organizations.

Effect of pulsed magnetic field on retained austenite of quenched 8Cr4Mo4V steel under cryogenic condition

High-intensity pulsed magnetic field was applied to modify the microstructure and mechanical propertis of quenched 8Cr4Mo4V bearing steel under the cryogenic environment. The microstructual transformation in 8Cr4Mo4V bearing steel was investigated by X-ray diffraction (XRD), Vibrating sample magnetometer (VSM) and Electron Backscatter Diffraction (EBSD) and so on. The results revealed that individual deep cryogenic treatment (DCT) promote the transformation from retained austenite (RA) in quenched steel to martensite. However, this phase transformation will be inhibited by coupling high-intensity magnetic field with deep cryogenic treatment (MDCT). For instance, the relative reduction of RA content in DCT samples was 10 ± 2%, while that in MDCT samples was 3 ± 3%. Furthermore, the modified Williamson-Hall method was utilized to estimate the dislocation characteristics based on XRD profile analysis. It exhibited that the proportion of edge dislocation significantly decrease from 61.8% to 43.7% by DCT, while this type of dislocation remains almost unchanged after MDCT. Moreover, the microhardness of quenched 8Cr4Mo4V steel became more uniform after MDCT than that of DCT. It can be indicated that the martensite transformation is blocked and carbon cluster is dissolved under the condition of coupling pulsed magnetic field treatment.

Effect of pulsed magnetic field in murine T lymphoma EL4 cells

Maintenance of homoeostasis in human body is a very important indicator in all cell activities. When exposed to a disease, various immune cells are activated due to the inflammatory response, and particularly T cells play a role in inducing apoptosis of mutated cells such as tumor cells. When the activity of T cells is very low, infection by external invasion is easy, and on the contrary, excessive activation leads to chronic inflammation caused by autoimmune diseases. Many clinical studies related to pulsed magnetic field (PMF) demonstrated its efficacy in reducing pain, improving blood circulation, as well as blood’s acid-base balance. Therefore, our study has tried to investigate the influence of PMF on the regulation of acid-base homeostasis in EL4 T lymphoma cell. In addition, we have tried to explain the role of PMF on immune cell activity by measuring the level of pro-inflammatory cytokine, TNF-α in culture supernatants. EL4 cells were cultured in a DMEM medium supplemented with 10% FBS and 1% penicillin in an incubator at 37 °C and 5% CO2 condition. Our PMF stimulator has the maximum strength of 4700 G at a transition time of 222 μs with pulse intervals of 1 Hz. The homoeostasis in pH was improved as PMF strength increases. Cell viability decreased by 32% after PMF stimulation of 4700 G. It was observed that the concentration of TNF-α, a cytokine related to inflammation, also decreased as the strength of PMF increased. These results suggest that PMF stimulation improves the anti-inflammatory effect, therefore, it is thought to affect the immune system by balancing the activation and suppression of immune cells. For clinical use, our study might suggest non-invasive PMF can be developed as a medical devices modulating immune system, although it is necessary to optimize the PMF conditions such as pulse shape, duration, or repetition rate.

Effects of pulsed magnetic field on the flight and impact of supersonic plasma spraying particles and the properties of coatings

In order to study the mechanism of pulsed magnetic field in supersonic plasma spraying process, the preparation of a Ni60 coating by pulsed magnetic field (PMF)-assisted supersonic plasma spraying was studied theoretically and experimentally to characterise the flight, impact, and spread behaviours of coating powder particles as well as stacking results and thus gain valuable mechanistic insights. PMF application made the particle flight paths converge inward, the flight speed decrease, decelerated the temperature drop, improved the particle melting state, promoted impact location concentration, afforded a more uniform particle morphology, and hindered breaking and splashing to increase the hardness, bonding strength, residual compressive stress, and compactness of the deposited coating. The obtained results provide a solid basis for the study of PMF–assisted supersonic plasma spraying.

The effects of pulsed magnetic field on the key elements responsible for synthesis and destruction of elastin-collagen in diabetic lung tissue

The effects of pulsed magnetic field on the key elements responsible for synthesis and destruction of elastin-collagen in diabetic lung tissue

Pulsed magnetic field impact on adaptation and vegetation of strawberry microplants (<i>Fragaria×ananassa</i> Duch.)

Microplant adaptation to non-sterile conditions is critical in clonal micropropagation providing for plant establishment and the overall method efficiency. Various techniques are employed to facilitate microplant establishment, including physical exposures like pulsed magnetic field. The study aimed to investigate the effect of pulsed magnetic field on establishment during adaptation to non-sterile conditions and subsequent vegetation of adapted strawberry plants. Research focused on strawberry microplants of the Tsaritsa and Nashe Podmoskovye cultivars originated by the All-Russian Horticultural Institute for Breeding, Agrotechnology and Nursery. Magnetic pulse treatment (MPT) was carried out with an AMIS-8 magnetic stimulator developed at the Institute. A positive impact of some MPT modes on microplant establishment, leaf and stolon formation was registered during strawberry adaptation to non-sterile conditions. Relatively low frequencies of 0.8-21 Hz exerted best effect in strawberry for most criteria. MPT contributed to an 11.5 % improvement in microplant establishment in Nashe Podmoskovye and 23.1 % — in Tsaritsa cultivars vs. no treatment. In best MPT assays, the number of leaves increased by 9.2—15.4 % and of stolons — 6.2-6.5 times in adapted strawberry plants compared to control. No significant inter-varietal differences were observed in Nashe Podmoskovye and Tsaritsa for vegetation criteria during adaptation to non-sterile conditions.

The healing effect of pulsed magnetic field on burn wounds

A burn is one of the most difficult injuries people can face.The primary pathology is coagulation necrosis resulting from tissue damage.Many wound care products have been developed to be used in situations such as the poor general condition of the patient and lack of solid area to be grafted. However, the high costs of these products make their use complicated.In this study, the effect of PEMF on cutaneous wound healing in an animal burn model was evaluated and the dose and duration of the magnetic field should be discussed for this effect to occur. Animals were divided into five groups including eight each (n = 40) (Groups 1, 2, 3, 4, 5).Group 1 was the control group; received no treatment after second-degree burn wound. Group 2 received daily wound care with saline. Group 3 received daily wound care with pomade containing mupirocin. Group 4 received Pulsed Electromagnetic Field signal for 60 min (1.5 m T and 40 Hz for seven days and Group 5 also received PEMF signal for 60 min the same frequency and intensity for14 days. Microscopically, second-degree burn wounds were successfully detected in all rats. Histopathological examination results in no significant difference between groups in neutrophil infiltration. The difference between the groups in vascularization was statistically significant between Group II and Group V (p < 0.001) and between Group I and Group V (p = 0.005) Epithelialization was present in 75% of the rats in Group V, while no epithelialization was observed in any of the other groups. In conclusion, we observed a significant improvement in the stasis zone of the group receiving Pulsed Electromagnetic Field for two weeks.

Effects of pulsed magnetic field on density reduction of high flow velocity plasma sheath

A three-dimensional model is proposed in this paper to study the effect of the pulsed magnetic field on the density distribution of high flow velocity plasma sheath. Taking the typical parameters of plasma sheath at the height of 71 km as an example, the distribution characteristics and time evolution characteristics of plasma density in the flow field under the action of pulsed magnetic field, as well as the effect of self-electric field on the distribution of plasma density, are studied. The simulation results show that pulsed magnetic field can effectively reduce the density of plasma sheath. Meanwhile, the simulation results of three-dimensional plasma density distribution show that the size of the density reduction area is large enough to meet the communication requirements of the Global Position System (GPS) signal. Besides, the location of density reduction area provides a reference for the appropriate location of antenna. The time evolution of plasma density shows that the effective density reduction time can reach 62% of the pulse duration, and the maximum reduction of plasma density can reach 55%. Based on the simulation results, the mechanism of the interaction between pulsed magnetic field and plasma flow field is physically analyzed. Furthermore, the simulation results indicate that the density distributions of electrons and ions are consistent under the action of plasma self-electric field. However, the quasi neutral assumption of plasma in the flow field is not appropriate, because the self-electric field of plasma will weaken the effect of the pulsed magnetic field on the reduction of electron density, which cannot be ignored. The calculation results could provide useful information for the mitigation of communication blackout in hypersonic vehicles.

Effects of pulsed magnetic field on microbial and enzymic inactivation and quality attributes of orange juice

Pulsed magnetic field (PMF, 5–7 T, 5–30 pulses) was applied to orange juice to evaluate its effects on inactivation of microbiota and enzyme and quality attributes. PMF decreased the activities of mesophilic baceria and yeast and mold by the highest log reduction of 0.61 at 7 T with 20 pulses and 0.36 at 7 T with 30 pulses, respectively. Peroxidase (POD) and pectin methylesterase (PME) activities were partially inactivated. PMF showed a good potential to inactivate PME and the lowest residual activity of PME was 50.28% obtained at 6 T with 20 pulses. No significant change in soluble solids and small changes in the pH, titratable acidity, and color were observed after PMF treatment. PMF brought about a slight decrease of ascorbic acid, phenolic compounds, and antioxidant capacity (DPPH​ and ABTS) in orange juice. Therefore, PMF appears to be a promising technogy involving microbial and enzymic inactivation with small changes in juice quality. Novelty Impact Statement Pulsed magnetic field could inactivate mesophilic bacteria and yeast and mold in orange juice. Pulsed magnetic field had a good potential to inactivate pectin methylesterase in orange juice. The minor quality degradation in orange juice was observed after pulsed magnetic field treatment.

Density reduction on plasma sheath using pulsed magnetic field

When a space vehicle travels through the atmosphere at a hypersonic speed, it is enveloped by a plasma sheath. The density of plasma sheath is high enough such that communication and telemetry signals are prevented from passing to and from the vehicle, which is called communication blackout. A method to reduce plasma density for communication blackout mitigation by using pulsed magnetic field is proposed in this paper. In order to study the effect of pulsed magnetic field on plasma density, a two-dimensional axisymmetric model was established. The simulation results suggested that the pulsed magnetic field can reduce the plasma sheath density of 5 cm thickness by more than 90%, and was of sufficient size (about 5 cm) and time duration (about 330 μs) to permit transmission of data. On the basis of the simulation results, the interaction mechanism between pulsed magnetic field and plasma is explained by theoretical analysis. Furthermore, experiments of the plasma density reduction by pulsed magnetic field are performed. The experimental results suggested that a 0.55T pulsed magnetic field can reduce the plasma sheath density of 14 cm thickness by 43%–78%, which verifies the effectiveness of the pulsed magnetic field method. A comparison of results from simulation and experiment provided strong evidence for the correctness of the simulation model. The simulation results also show that low pressure and high initial electron density are beneficial to the reduction of plasma density, which also explains the phenomenon in the experiment. In addition, it is found in the experiment that two continuous reverse pulses can play the same role in reducing the plasma density, which provides the possibility for the continuous reduction of plasma density. These investigations could have a significant benefit on the design and optimization of pulsed magnetic field mitigation scheme for the blackout problem.

Effect of pulsed magnetic field on seed borne pathogen and germination of tomato

Effect of Pulsed Magnetic Field (PMF) treatment on the control of Alternaria solani (Ellis and Martin) Jones and Grout causing Early blight of tomato (Solanum lycopersicum L.) cultivar PKM 1 was studied. The seeds pre-inoculated with A. solani were 1500nT PMF treated with frequency of 10 Hz for 5 h for varied durations of 0, 5, 10, 15, 20 and 25 days. PMF treatment significantly reduced pathogen incidence and increased both germination and plant growth in comparison with the control. Experimental results indicated that all the treatments were significantly different and the seeds treated for 20 and 25 days showed the minimum percent disease incidence (71%) with highest percent disease inhibition over control (29%). It also recorded the highest plant biometrics viz., germination (81%), speed of germination (7.74), root length (13.37 cm), shoot length (6.45 cm) and vigour index (1606). Control recorded the minimum plant biometrics viz., germination (61%), speed of germination (7.27), root length (12.92 cm), shoot length (6.17 cm) and vigour index (1164).

The influence of pulse magnetic field intensity on the morphology and electrochemical properties of NiCoS alloys

In this study, we synthesized arrayed NiCoS alloys as electrode material of supercapacitors via a customized hydrothermal reaction device assisted by pulse magnetic field and studied the effect of pulse magnetic field intensity on the morphology and electrochemical performances of NiCoS alloys. The results showed that the diameter of the rod-shaped NiCoS alloys reaches its minimum value of 10 nm and the arrangement of the arrayed grains is most regular at a peak current density of 9Adm−2 flowing through the electromagnetic induction coil. Consequently, the specific capacity of that sample reaches a maximum value of 161.2 mAhg−1 at 2Ag−1, which drops to 118.7 mAhg−1when the current density increases from 2Ag−1 to 10 Ag−1. The optimized sample also exhibits an excellent long-term cycling performance with a retention ratio of 84.6% over 5000 cycles in 2 M KOH electrolyte. The remarkable electrochemical performances may be attributed to the effect of pulse magnetic field on the nucleation and growth of NiCoS alloys, which could enlarge its surface area and improve its crystal dendrite quality.

Numerical study of flow and heat transfer behaviors during direct-chill casting of large-size magnesium alloy billet under pulsed magnetic field

Purpose The purpose of this paper is to investigate the effect of pulsed magnetic field (PMF) with different duty cycles on the melt flow and heat transfer behaviors during direct-chill (DC) casting of large-size magnesium alloy billet and find the appropriate range of duty cycle. Design/methodology/approach A transient two-dimensional mathematical model coupled electromagnetic field, flow field and thermal field, is conducted to study the melt flow and temperature field under PMF and compared with that under the harmonic magnetic field. Findings The results reveal that melt vibration and fluctuation are generated due to the instantaneous impact of repeated thrust and pull effects of Lorentz force under PMF. The peak of Lorentz force decreases greatly with the increasing duty cycle, but the melt fluctuation region is expanded with higher duty cycle, which accelerates the interior melt velocity and reduces the temperature gradient at the liquid-solid interface. However, PMF with overly high duty cycle has adverse effect on the melt convection and limited influence on the interior melt. A duty cycle of 20% to 50% is a reasonable range. Practical implications This paper can provide guiding significance for the setting of duty cycle parameters on DC casting under PMF. Originality/value There are few reports on the effect of PMF parameters during DC casting with applying PMF, especially for duty cycle, a parameter unique to PMF. The findings will be helpful for applying the external field of PMF on DC casting.

Effects of pulsed magnetic field on freezing kinetics and physical properties of water and cucumber tissue fluid

In this paper, a special experimental device was designed to study the effect of pulsed magnetic fields (PMF) on freezing kinetics and physical properties of water and cucumber tissue fluid. Pure water and cucumber tissue fluid samples with 3.5 mL were frozen in PMF generated by a pair of Helmholtz coils. The magnetic flux density ranged from 0 to 6 mT in the experiment. The results show that PMF treatment significantly reduced the freezing point temperature (Tice) of water and cucumber tissue fluid with 0.59 °C and 0.74 °C, respectively. Within a certain range of magnetic flux density, PMF treatment not only significantly reduced initial nucleation temperature and the temperature of end point of freezing, but also significantly reduced the phase transition time and the tempering time of both water and cucumber tissue fluid. However, the effects of PMF treatment on the total freezing time of water and cucumber tissue fluid were different. These may be related to the effects of Lorentz forces generated by PMF on the hydrogen bonds, water molecule clusters, ice crystals, charged particles and ferromagnetic particles in the fluid.

Effect of pulsed magnetic field on electron acceleration due to plasma wave generated by plane polarised laser

Electron acceleration due to plasma wakefield generated by plane polarised laser field in the presence of pulsed magnetic field has been investigated. Laser propagation is considered in transverse direction to the plasma wave. The electron gets trapped in the plasma wakefield and excited in the combined effect of plasma and laser fields. The pulsed magnetic field induces a resonant effect and contributes to additional gain in the electron energy. Laser, plasma and applied magnetic field parameters are optimized to achieve high energy gain.

Effect of Combined Pulsed Magnetic Field and Cold Water Shock Treatment on the Preservation of Cucumbers During Postharvest Storage

The aim of this study was to evaluate the combined effect of pulsed magnetic field (PMF) and cold water shock pretreatment on the quality of postharvest cucumbers. Cucumbers were immersed into cold water at 0.5 °C with PMF for 40 min and then stored at 6 °C for 13 days. Different levels of the PMF (0.0, 2.0, 4.0, and 6.0 mT) were applied with a frequency of 25 Hz. The results showed that combined pretreatments of PMF and cold water possessed better preservation quality and prolonged their shelf life. When the magnetic flux density of PMF was 4.0 mT, the color change and decay rate of samples were the lowest and decreased by 52.8% and 73% at 13 days. The preservation mechanism of combined PMF and cold water may be ascribed to triggering higher catalase activity, which induced higher membrane integrity that displayed lower malondialdehyde accumulation.

Effects of Pulsed Magnetic Fields of Different Intensities on Dislocation Density, Residual Stress, and Hardness of Cr4Mo4V Steel

To study the effects of pulsed magnetic fields of different intensities on the dislocation density, residual stress, and hardness of Cr4Mo4V steel, magnetic treatment is conducted at 0, 1.0, 1.3, 1.5, 2.0, and 2.5 T. The dislocation density and residual stress are measured using Electron Backscatter Diffraction (EBSD) and X-ray technique, respectively. The results reveal the dislocation density and compressive residual stress decrease at lower magnetic fields such as 1.0 T and 1.3 T, while they increase at higher magnetic fields such as 2.0 T and 2.5 T. The average value of kernel averaged misorientation (KAM) and compressive residual stress decrease about 10.4% and 15.8%, respectively, at 1.0 T, while they increase about 5.88% and 18.2%, respectively, at 2.5 T. The average value of hardness decreases about 3.5% at 1.0 T, from 817 HV to 787 HV. With the increments of intensities, the hardness of the treated samples increases. The hardness essentially remains unchanged at 2.0 T and 2.5 T. The reason for the dislocation motion under the action of pulsed magnetic fields is discussed.