High-intensity Magnetic Field Research Articles

High-sensitivity vector magnetic field sensor based on a V-shaped multimode-no-core-multimode fiber structure.

This work proposes and investigates a bent multimode-no-core-multimode optical fiber structure for vector magnetic field sensing applications. The bent no-core fiber (NCF) serves as the sensing area, and the gold film is deposited on its surface to excite the surface plasmon resonance effect. Due to the strong evanescent field of the unclad and bent NCF, the as-fabricated sensor exhibits a high sensitivity of 5630 nm/RIU in the refractive index range of 1.36-1.39. Magnetic fluid is employed as the magneto-sensitive material for magnetic field sensing, exhibiting a high magnetic field intensity sensitivity of 5.74 nm/mT and a high magnetic field direction sensitivity of 0.22 nm/°. The proposed sensor features a simple structure, low cost, point sensing, and excellent mechanical performance.

The significant role of Darcy–Forchhiemer with integrated hybrid nanoparticles (Graphene and TiO 2) on dusty nanofluid flow subjected to heat conduction

The thermal analysis of two-phase models that deal with the fluid and dusty phases has been considered. This study instigates the flow of a non-miscible, dusty hybrid nanofluid over a stretching cylinder with Darcy–Forchheimer permeability in the presence of thermal radiation. The mathematical model is based on the single-phase nanofluid model, which features modified thermophysical characteristics. This innovative flow model explores how important it is to enhance the concentration of dust particles in fluid dynamics. Hybrid nanoparticles are substituted for nanoparticles in a conventional case to accelerate the heat transfer rate of the fluid. Therefore, in this study, the magnetohydrodynamic flow of hybrid nanofluids and heat transfer of non-Newtonian dusty fluids with suspensions of hybrid nanoparticles have been examined. The appropriate dimensionless variables are used to convert the governing periodic model into a non-dimensional form. The finite-difference-based bvp5c algorithm is used through Matlab for numerical analysis of the set of obtained ordinary differential equations. The graphs explored the influences of relatable factors over the profiles of mass, heat, and velocity transfers. It is observed that with intensifying values of Eckert number (Ec) and Biot number (Bi), the temperature of both phases increased at a significant level, and the velocity decreased with increasing intensity of the magnetic field. The computational results of velocity, core temperature, and intensity dispersion are significant for both aspects. Furthermore, it is observed that both the fluid and dust phases exhibit declining behavior as a result of the impact of porosity, mass concentration, and magnetism on the flow stream. Moreover, it is noticed that both the dust phase temperature θ p ( η ) and fluid phase temperature θ ( η ) intensified with the high intensity of magnetic field and thermal radiation. The missile nozzles, nuclear power plants for aerospace and gaseous-core nuclear rocket systems, and the radiation are considered for evaluating heating significance.

Influence of SPION Surface Coating on Magnetic Properties and Theranostic Profile.

This study aimed to develop multifunctional nanoplatforms for both cancer imaging and therapy using superparamagnetic iron oxide nanoparticles (SPIONs). Two distinct synthetic methods, reduction-precipitation (MR/P) and co-precipitation at controlled pH (MpH), were explored, including the assessment of the coating's influence, namely dextran and gold, on their magnetic properties. These SPIONs were further functionalized with gadolinium to act as dual T1/T2 contrast agents for magnetic resonance imaging (MRI). Parameters such as size, stability, morphology, and magnetic behavior were evaluated by a detailed characterization analysis. To assess their efficacy in imaging and therapy, relaxivity and hyperthermia experiments were performed, respectively. The results revealed that both synthetic methods lead to SPIONs with similar average size, 9 nm. Mössbauer spectroscopy indicated that samples obtained from MR/P consist of approximately 11-13% of Fe present in magnetite, while samples obtained from MpH have higher contents of 33-45%. Despite coating and functionalization, all samples exhibited superparamagnetic behavior at room temperature. Hyperthermia experiments showed increased SAR values with higher magnetic field intensity and frequency. Moreover, the relaxivity studies suggested potential dual T1/T2 contrast agent capabilities for the coated SPpH-Dx-Au-Gd sample, thus demonstrating its potential in cancer diagnosis.

The search for new pathogenesis of cardiorenal syndrome: the effect of local Schumann resonance on the occurrence of episodes of kidney disease and myocardial infarction

Background. The pandemic of noncommunicable chronic diseases and the high prevalence of combined damage to the cardiovascular system and kidneys determine the relevance of continuing scientific research to solve these medical problems. Therefore, the aim of this study was to compare the influence of the Earth’s electromagnetic field on the occurrence of episodes of kidney disease and myocardial infarction in order to search for new pathogenetic components of cardiorenal syndrome and deepen fundamental knowledge. According to the Lithuanian magnetometer GCI003, a number of stu­dies in 2014–2018 found that changes in the Earth’s electromagnetic field may play an important role in the pathogenesis of cardiovascular diseases as well as their incidence. Since the functioning of the cardiovascular system and kidneys are closely connected through the metabolic processes of the cardiorenal metabolic axis, this study tested the hypothesis that changes in the Earth’s electromagnetic field may also affect the pathogenesis of kidney disease as the changes of local magnetic field have been shown to influence the functioning of the cardiovascular system. Materials and methods. This was a search retrospective study on the relationship between the influence of local Schumann resonances and the occurrence of hospitalizations in 1340 patients with kidney disease. It also examined the relationship between local Schumann resonances and heart attacks in patients admitted to the University Hospital of the Lithuanian University of Health Sciences (703 patients). Mean power of local magnetic field fluctuations in Lithuania was measured in pT2 s2 in five different frequency ranges, which overlaps the Schumann resonance and electroencephalogram’s frequency ranges: SDelta (0–3.5 Hz), STheta (3.5–7 Hz), SAlpha (7–15 Hz), SBeta (15–32 Hz), SGamma (32–66 Hz). The data of hospitalizations to the Nephrology Department of University Hospital and the dynamics of Schumann resonances were analyzed from January 1, 2021 to December 31, 2021. The data of hospitalizations for myocardial infarction to the Cardiology Department of University Hospital and the dynamics of Schumann resonances were studied from January 1, 2016 to December 31, 2016. Results. It was found that changes in the strength of the Earth’s local magnetic field in 2016 and 2021 were comparable and corresponded to the characteristic annual dynamics of the Earth’s local electromagnetic fields. This made it possible to conduct a comparative analysis of annual correlation graphs and establish general trends in the dynamics of indicators and graphical similarities. It confirmed the pre­sence of a general dependence of reactions to the external electromagnetic field of the Earth in female and male patients both with nephrological pathology and myocardial infarction. In nephrological patients of both sexes, all correlation coefficients in all ranges of Schumann resonances were positive. The only negative correlation coefficient P5 (SGamma) [32; 65] Hz (r = –0.069; p = 0.313) was in the female group. This fact as well as the presence of a significant dynamics of the correlation coefficient P5 (SGamma) [32; 65] Hz (r = 0.009; p = 0.475) in the male group indicate that higher magnetic field strength in this frequency range may be associated with a reduced incidence of kidney disease. We obtained data that a higher magnetic field intensity in the gamma range from 32 to 65 Hz as a pathogenetic component can contribute to the destabilization of the cardiovascular system, but at the same time it is associated with a positive effect on the state of nephrological pathology. Based on this, we can tentatively assume the opposite direction of the Earth’s electromagnetic field influence on the pathogenetic mechanisms of renal and cardiovascular diseases. This is clearly demonstrated by comparing the correlation coefficients between the incidence of kidney disease and the occurrence of myocardial infarction in men and women. The Earth’s stronger magnetic field in the gamma range contributes to an increase in the incidence of myocardial infarction, which is confirmed by the large number of patients during this period. Under these same conditions, a decrease in the incidence of kidney disease has been detected. This opposite direction is observed in both sexes. But in women the reaction is stronger, which is confirmed by a larger difference in correlation coefficients. Conclusions. 1. Changes in the Earth’s electromagnetic field are related to the functional state of the cardiovascular system and the condition of the kidneys. 2. It can be assumed that the effect of the Earth’s electromagnetic field on the pathogenetic mechanisms of kidney disease is in the opposite direction of that on the cardiovascular one. 3. Reliable gender differences in correlations between the influence of changes in the local Schumann resonance on the functional state of the cardiovascular system and kidneys were not found. 4. The connection of the Earth’s local geomagnetic field with kidney function may be another new unexplored pathogenetic mechanism in cardiorenal syndrome and noncommunicable chronic diseases.

Effectiveness of Sanatorium Treatment Programs for Women with Chronic Endometritis: a Prospective Randomized Study

INTRODUCTION. The problem of recurrent antibiotic-resistant urogenital infections is increasing, and standard therapy is becoming ineffective. Sanatorium-resort treatment of chronic inflammatory diseases of the pelvic organs in women allows us to solve these problems with the help of natural and preformed physical factors.
 AIM. To study the clinical effectiveness of comprehensive sanatorium treatment programs in patients with chronic endometritis.
 MATERIALS AND METHODS. A prospective randomized trial included 73 patients, aged 35 ± 10 years, diagnosed with chronic endometritis. The control group (n = 25) received «basic» therapy with amplipulstherapy, sodium chloride baths. The comparison group (n = 24) received «basic» therapy and manual therapy. The main group (n = 24) received «basic» therapy, high-intensity pulsed magnetic field and manual therapy. Diagnostic criteria: immunohistochemical examination of the endometrium, echographic examination, dopplerometry of pelvic vessels, laser Doppler flowmetry.
 RESULTS AND DISCUSSION. After treatment, an increase in the uterine arterial perfusion index was noted in all groups compared with baseline values. The median indicator increased in the study groups by 2.36 times, 2.4 times, and 2.6 times, respectively (p 0.05). The decrease in the maximum peak speed in the comparison group and the main group exceeded the indicators of the control group (p 0.001). The systolic-diastolic ratio decreased in the comparison group and the main group (p 0.05). A decrease in stagnation in the venular microcirculation, a normotonic type of microcirculation, improvement in endothelial function (p 0.01) were revealed in the main group.
 CONCLUSION. An algorithm has been developed. In case of endometrial hypoplasia, decreased uterine perfusion, increased uterine artery resistance index, «basic» therapy is recommended, including sodium chloride baths and amplipulstherapy. With an increase in the maximum peak blood flow rate, an increase in the systolic-diastolic ratio, it is necessary to add a course of manual therapy to the «basic» therapy. When detecting violations of venous outflow, it is recommended to include high-intensity pulsed magnetic therapy.

A multi-region and a multiphase MHD OpenFOAM solver for fusion reactor analysis

Several systems in nuclear fusion reactors utilize liquid metals as working fluids and the design of these systems cannot overlook the magnetohydrodynamics effects arising from the interaction between the electrically conductive fluid and the magnetic fields used to confine the plasma, since these effects significantly influence the flow features. In this context, rigorous studies and research activities are imperative to provide high–quality numerical data and develop precise predictive numerical tools. This work introduces two OpenFOAM magnetohydrodynamics solvers and outlines their respective validation processes. The mMRF solver can simulate single–phase, incompressible MHD flow for multiple electro–coupled domains. Meanwhile, the mIF solver is capable of simulating two–phase MHD flow involving incompressible and immiscible fluids. The mMRF solver has demonstrated outstanding results in simulating classical 2D benchmarks up to high magnetic field intensities, while the mIF solver proved its ability by estimating, with a discrepancy of less than 10%, the velocity of a bubble rising within a liquid metal under an imposed magnetic field.

Quantum correlations and coherence in a mixed spin- (12,1) Heisenberg dimer under intrinsic decoherence

This research delves into the dynamical behavior of quantum correlations and coherence within a mixed Heisenberg dimer system under the intrinsic decoherence. Our approach involves the application of logarithmic negativity, local quantum uncertainty, and the ℓ 1 norm-based coherence as quantifiers for entanglement, skew information correlations, and quantum coherence in this qubit-qutrit model. Our primary objective is to explore the impact of various factors on the dynamics of quantum correlations and quantum coherence. These factors encompass the initial density matrix and its mixing parameter, the intrinsic decoherence rate (γ), the external magnetic field, as well as intrinsic system parameters, notably the XXZ and uniaxial single-ion anisotropies. Our results demonstrate that the introduction of intrinsic decoherence (ID) significantly erodes quantum resources. Particularly, for high values of the ID rate (γ), excessive damping occurs, leading to the absence of oscillations or a rapid decay of quantum resources, ultimately stabilizing in steady states. Furthermore, the presence of an external homogeneous magnetic field further diminishes quantum resources within the system. However, despite the degradation induced by the combined influence of intrinsic decoherence and high external magnetic field intensities, the judicious selection of the initial density matrix and precise adjustment of the uniaxial single-ion anisotropy enable the preservation of quantum resources within the mixed spin-(1/2, 1) Heisenberg dimer.

Vibration Analysis of PMLSM Considering Magnetostriction under High-intensity Magnetic Fields

Vibration Analysis of PMLSM Considering Magnetostriction under High-intensity Magnetic Fields

Influence of uniaxial tensile strain on magnetization behavior of Fe-9wt%Ni steel

This study investigated the effects of uniaxial tensile strain on the magnetization process of an Fe-9wt%Ni (9Ni) alloy to increase understanding of its magnetic behavior. As the applied strain was increased from 0 to 14 %, the magnetization curve changed remarkably, particularly under a high-intensity magnetic field, and magnetic flux density, relative permeability, remanence, and coercive force degraded significantly, especially at strains greater than the upper yield point. Increase in tensile strain caused increase in hysteresis losses, primarily because strain induced crystal defects, which affected the rearrangement of magnetic domains. Increased dislocation density was the primary contributor to the observed deterioration in magnetic properties; changes in texture and phase had little influence. This finding indicates that strain-induced deformation strongly affects the magnetic behavior of 9Ni alloys; this insight will be useful in research aimed at mitigating welding defects such as arc blow, that are attributed to the magnetization of Ni steel.

Evaluation of the effectiveness of complex physical therapy and SIS-therapy in the treatment of cervical disc herniation in the cervical spine

This article provides a review of the literature evaluating treatments for cervical disc herniation.
 As the most common cause of neck pain and even disability, cervical disc herniation often requires a multifaceted approach to treatment. The author examines the effectiveness of complex exercise therapy, including a number of therapeutic exercises and methods of manual therapy and SIS-therapy, using a high-intensity magnetic field. The review contains a description of various clinical trials, and also presents comparative functional characteristics of these methods to assess the effectiveness, safety and effectiveness of treatment. The author conducted a comparative analysis of the SIS-therapy method with the exercise therapy method in the treatment of herniated discs of the cervical spine based on consideration of such aspects of their impact as the mechanism of action, effectiveness, safety, accessibility and convenience, time and cost, and overall impact on health. The results show that complex exercise therapy and SIS-therapy are the most promising non-invasive treatment methods that can significantly improve the degree of pain relief, mobility and overall quality of life of patients with cervical disc herniation. The article provides recommendations for the implementation of these treatment methods in clinical practice and suggestions for further directions of research.

Modeling methodology for the transformer-rectifier flux pump considering electromagnetic and thermal coupling

High-temperature superconducting (HTS) magnets are promising in the application of high-intensity magnetic field. HTS flux pumps are devices that can charge closed HTS magnets without direct electrical contact. Simulation is an effective way to clarify the physical mechanism and provide further insight into the design of the device. In this work, we propose an accurate and efficient modeling methodology to simulate the transformer-rectifier HTS flux pump, which has considered electromagnetic and thermal coupling. The validity of the model has been verified by experimental results and theoretical calculations. The working characteristics of the HTS flux pump are investigated based on the proposed model, including DC bias component in the charging loop, the voltage recovery delay of the dynamic bridge and the temperature distribution in the dynamic bridge. The simulation results clearly depict working details of the device, in terms of electricity, magnetism and heat. The proposed model can serve as a powerful tool to design the HTS flux pump in practical applications.

A lightweight super-resolution network with skip-connections.

In some hospitals in remote areas, due to the lack of MRI scanners with high magnetic field intensity, only low-resolution MRI images can be obtained, hindering doctors from making correct diagnoses. In our study, higher-resolution images were obtained through low-resolution MRI images. Moreover, as our algorithm is a lightweight algorithm with a small number of parameters, it can be carried out in remote areas under the condition of the lack of computing resources. Moreover, our algorithm is of great clinical significance in providing references for doctors' diagnoses and treatment in remote areas. We compared different super-resolution algorithms to obtain high-resolution MRI images, including SRGAN, SPSR, and LESRCNN. A global skip connection was applied to the original network of LESRCNN to use global semantic information to get better performance. Experiments reported that our network improved SSMI by 0.8% and also achieved an obvious increase in PSNR, PI, and LPIPS compared to LESRCNN in our dataset. Similar to LESRCNN, our network has a very short running time, a small number of parameters, low time complexity, and low space complexity while ensuring high performance compared to SRGAN and SPSR. Five MRI doctors were invited for a subjective evaluation of our algorithm. All agreed on significant improvements and that our algorithm could be used clinically in remote areas and has great value. The experimental results demonstrated the performance of our algorithm in super-resolution MRI image reconstruction. It allows us to obtain high-resolution images in the absence of high-field intensity MRI scanners, which have great clinical significance. The short running time, a small number of parameters, low time complexity, and low space complexity ensure that our network can be used in grassroots hospitals in remote areas that lack computing resources. We can reconstruct high-resolution MRI images in a short time, thus saving time for patients. Our algorithm can be biased towards practical applications; however, doctors have affirmed the clinical value of our algorithm.

Investigation of the beneficiation of refractory ferromanganese ores “Zhomart” deposits

In order to provide ferroalloy production with high-quality raw materials, the need to develop technologies for processing of low-grade manganese and ferromanganese ores is becoming increasingly important. In view of the change in the quality characteristics of ores, the decrease in manganese content and the ability to beneficiation by traditional methods, it is necessary to consider new approaches and technological solutions. The article presents data from a study on the beneficiation of refractory iron-manganese ore from the Zhomart deposit. The mineralogy, physical and mechanical properties, and granulometric composition of the ore were determined. The results of a study on gravitational beneficiation using a laboratory pulsator with a pneumatic drive and a laboratory 2-chamber diaphragm jigging machine and magnetic beneficiation of ore with a high-intensity magnetic field are presented. Iron-containing concentrate (Fe-45% and Mn-6.5% is mainly represented by hematite mixed with non-metallic minerals quartz and calcite) and iron-manganese concentrate (Mn-21.7% and Fe-21.1% in the form of hematite, Brownite and pyrolusite, also mixed with quartz and calcite). The concentrates are not suitable for smelting manganese-containing ferroalloys but can be used in the process of electrothermal beneficiation with selective carbothermal reduction of iron in an ore-thermal furnace. The smelting products can be manganese cast iron and iron-free, low-phosphorus limiting manganese slag with a high ratio of manganese to iron.

7T Magnetic Compatible Multimodality Electrophysiological Signal Recording System

This paper developed a comprehensive magnetic resonance imaging (MRI)-compatible electrophysiological (EP) acquisition system, which can acquire various physiological electrical signals, including electrocardiography (ECG), electromyography (EMG), electroencephalography (EEG) and electrocorticogram (ECoG), and EP recording combined with multimodal stimulation. The system is designed to be compatible with the 7-Tesla (7T) ultra-high field MRI environment, providing convenience for neuroscience and physiological research. To achieve MRI compatibility, the device uses magnetically compatible materials and shielding measures on the hardware and algorithm processing on the software side. Different filtering algorithms are adopted for different signals to suppress all kinds of interference in the MRI environment. The system can allow input signals up to ±0.225 V and channels up to 256. The equipment has been tested and proven to be able to collect a variety of physiological electrical signals effectively. When scanned under the condition of a 7T high-intensity magnetic field, the system does not generate obvious heating and can meet the safety requirements of MRI and EEG acquisition requirements. Moreover, an algorithm is designed and improved to efficiently and automatically remove the gradient artifact (GA) noise generated by MRI, which is a thousand-fold gradient artifact. Overall, this work proposes a complete, portable, MRI-compatible system that can collect a variety of physiological electrical signals and integrate more efficient GA removal algorithms.

The High Arctic Large Igneous Province: first seismic-stratigraphic evidence for multiple Mesozoic volcanic pulses on the Lomonosov Ridge, central Arctic Ocean

We use seismic reflection data acquired by an over-winter expedition on drifting sea ice in the central Arctic Ocean to explore a possible spatial and temporal magmatic relation between the sub-bottom geology of part of the deep Arctic Ocean and the Mesozoic volcanic rocks found on the islands and the bordering continental shelf of Franz Josef Land and Svalbard. The new dataset from the North American segment (85–90°N) of the Lomonosov Ridge, central Arctic Ocean documents several Mesozoic volcanic pulses over a distance ofc.600 km along the ridge. This volcanism borders a domain of high magnetic field intensity over the adjacent Alpha Ridge in the deep basin where the magnetic source rocks and recent seismic reflection data indicate extensive Mesozoic magmatism. We suggest that the Mesozoic volcanism on the Lomonosov Ridge in its palaeo-position at the former continental margin north of Franz Josef Land and Svalbard spatially links the Mesozoic magmatic pulses of the continental High Arctic Large Igneous Province (HALIP) of polar Europe to volcanism on the adjacent Alpha Ridge in the deep Arctic Ocean. Increased input of heat to the upper crust on the Lomonosov Ridge enhanced maturation of hydrocarbon source rocks as manifested by the presence of gas or fluid escape pipes restricted to the area of volcanism.

Effect of Sepiolite on the Field-Dependent Normal Force of Magnetorheological Grease.

In order to investigate the influence of sepiolite minerals on the normal force of magnetorheological grease (MRG), a mixed sample (ALCH) on the basis of preparing an aluminum-lithium-based magnetorheological grease (base sample ALC), containing sepiolite was further prepared. The field-dependent normal force of the two samples was tested using a rotational rheometer, considering conditions such as magnetic field, time, strain amplitude, frequency, and temperature, and the results were compared. The results indicate that sepiolite limits the field dependent normal force of the magnetorheological grease under steady state shear, and is unaffected by magnetic field, time, temperature, and shear rate. Sepiolite has minimal impact on the transient response of the magnetorheological grease. Under oscillatory shear, the magnetic field is an important factor influencing the field-dependent normal force response of the sepiolite-magnetorheological grease (ALCH). At low magnetic fields, the field-dependent normal force of the sepiolite-containing sample (ALCH) is greater than that of the base sample (ALC), while this relationship is reversed at high magnetic fields, unaffected by other factors. Under long-term shear conditions, both samples exhibit good shear stability, as well as consistency at different frequencies and strain amplitudes. However, an increase in shear rate reduces the normal force, and temperature also affects the field-dependent normal force. The patterns of variation in steady-state and oscillatory shear modes are not entirely the same, but both exhibit a characteristic decrease with increasing temperature under high magnetic field intensities. Sepiolite can reduce the temperature sensitivity of the normal force of the magnetorheological grease. In conclusion, the introduction of sepiolite is beneficial for the application of magnetorheology in high-precision devices.

Application of high-intensity static magnetic field as a strategy to enhance the fertilizing potential of sewage sludge digestate

Anaerobic digestion (AD) is a sustainable and well-established option to handle sewage sludge (SS), as it generates a methane-rich biogas and a digestate with potential fertilizing properties. In the past, different strategies have been proposed to enhance the valorization of SS. Among these, the application of a static magnetic field (SMF) has been poorly evaluated. This study aims to determine the effects of a high-intensity SMF (1.5 and 2 T) on the chemical composition of SS anaerobic digestate. Several strategies (i.e., number of magnetization cycles, addition of different sources and quantities of magnesium, and digestate aeration) have been applied to evaluate the possible formation of compounds with valuable fertilizing properties in the digestate. Experimental results showed that by combining different strategies promoting digestate exposure to the magnetic field it is possible to favour the reduction in the liquid phase of NH4+, NO3−, PO43−, SO42− and Mg2+ concentrations up to 28%, 38%, 34%, 39% and 31%, respectively. The XRD analyses conducted on the solid phase of the same magnetized digestate samples showed an increase in crystalline and amorphous phases of nitrogen and phosphorus compounds with fertilizing value, such as struvite. These results highlight that SMF application can increase the fertilizing potential of sewage sludge digestate and promote its valorization in a sustainable and circular perspective.

MHD Couette flow and heat transfer in a rotating channel in presence of viscous dissipation and heat source/sink

The fully developed steady flow of an electrically conducting as well as heat-generating/absorbing fluid, in a horizontal rotating channel in the presence of viscous dissipation, has been studied. Further, the flow is subjected to shearing impact due to the motion of the upper plate. The effects of various parameters characterizing the translating and rotating flow and heat transfer phenomena, based on analytical solutions, are depicted with the help of graphs and tables. The solution of the boundary value problem has been carried out analytically and computations thereof with MATLAB code. The outcomes of the present study find applications in the motion of the rotor blade and turbine. The important findings are: the moderate speed of rotation gives rise to inconsistency in heat transfer, a transition state between low and moderately high speed, hence speed of the channel is to be taken care of for smooth and consistent heat transfer; the effect of entire values of Eckert number persists on the temperature distribution; the higher magnetic field intensity gives rise to convex type of temperature field (rise in temperature) resulting thicker thermal boundary layer; whereas the reverse is the case in the presence of sink. Most importantly, the inconsistency of heat transfer at the bounding surface is due to the interaction of electromagnetic force with the rotation of the channel.

Study on condition prediction and influencing factors of manganese carbonate recovery by high gradient pulse magnetic separation

Manganese carbonate ore belongs to weakly magnetic minerals, and its co-associated minerals are mainly non-magnetic minerals, which can be separated from gangue minerals at high magnetic field intensity. However, manganese grade and recovery of magnetic separation concentrate of manganese carbonate ore are low in actual production. Therefore, the influences of manganese carbonate particle size, magnetic field intensity, volume susceptibility, pulse stroke, pH, and other factors were studied. The optimal test conditions for manganese carbonate ore recovery by high-gradient magnetic separation were predicted through the calculation results. The results show that the particle radius of manganese carbonate is 0.020 mm, the pulse impulse time is 200 r/min, and the magnetic field intensity is 0.9 T. The optimum condition test was carried out with Qianbei manganese carbonate ore as the material. The test results show that the optimum conditions are the particle radius of 0.074-0.019 mm, pulse impulse time of 200 r/min, and magnetic field intensity of 1.2 T. The reason for the deviation is that the actual ore has a fine distribution particle size, many associative bodies, complex composition, and serious agglomeration, resulting in variable particle volume susceptibility. The capture yield increases with the increase of magnetic field intensity and volume susceptibility but decreases with the increase of pulse. The lower the surface potential of manganese carbonate, the higher the recovery of manganese carbonate. The grade of manganese concentrate was 19.06% and the recovery was 76.85%. Mixed manganese concentrate with a grade of 18.04% and recovery of 87.14% was obtained by adding drugs and changing the grinding method.

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.