Magnetic Field Intensity Research Articles

Inhibitory effect of magnetic aqueous extract of Syzygium aromaticum L on two types of oral pathogenic bacteria

<p><strong>Aim</strong> Magnetic fields affect all living things, which is why they are the subject of extensive research around the world. The aim of this study was to investigate the effects of different levels of static magnetic field on chemical behaviours of aqueous extract of <em>Syzygium aromaticum</em> L and their effect on selective oral pathogenic bacteria. <br /><strong>Methods</strong> This study utilized locally manufactured dipolar static magnetic fields with strengths between 1200 and 3200 Gauss, measured by a Sylocimol Residence magnetizer. Gram positive G (+) <em>Streptococcus viridans</em> and G negative (G-) <em>Porphyromonas gingivalis</em> strains were used in studies on the antimicrobial properties of <em>S. aromaticum</em> extract. Tests were carried out using the clove essential component (eugenol) and its functionalized extract to evaluate various bacterial inhibitions and establish whether there is a synergistic effect between the extract and subjected to the magnetic field. <br /><strong>Results</strong> Polyphenol extraction increased with eugenol content. The analytical method's reliability was confirmed by chromatograms of eugenol and eugenol acetate standards, demonstrating good separation of compounds. The selectivity of the method was guaranteed by the purity index of the eugenol and eugenol acetate peaks. The aqueous extract of <em>S. aromaticum</em> showed magnetic properties. The extract showed antimicrobial activity against two bacterial strains. Cell viability changed at different magnetic field intensities, and the inhibition zone for <em>P. gingivalis</em> increased significantly due to prolonged exposure.  <br /><strong>Conclusion</strong> The magnetized extract inhibits both G (+) and G (-) bacteria when combined with clove extract.</p>

Kinetics study on microbial growth and surfactin production of Bacillus subtilis ATCC 21332 under the synergistic effect of magnetic field and Mg2+

In this study, the kinetics of growth and surfactin production of Bacillus subtilis (B. subtilis) ATCC 21332 under different magnetic field (MF) exposure times, MF intensities and magnesium (Mg2+) concentrations in media were investigated using Logistic and Gompertz models. Results show that a 1.42-fold increase in surfactin titer was obtained under the optimal conditions with 58 h of MF exposure time, 24 mT MF intensity, and 1.1 mM Mg2+ in the medium. A synergistic effect on the biological fermentation process was observed between MF and Mg2+ to significantly enhance surfactin yield and production efficiency by B. subtilis. This was accompanied by increased biomass accumulation and a higher sugar consumption rate during fermentation. Additionally, the overall volumetric surfactin productivity (Prodvol) and the specific surfactin formation rate (qP) increased by 136% and 217%, respectively. This study provides valuable insights into the potential applications of MFs in manipulating bacterial growth and metabolism.

Constraints on axion-like particles from the gamma-ray observation of the Galactic Center

High energy photons originating from the Galactic Center (GC) region have the potential to undergo significant photon-axion-like particle (ALP) oscillation effects, primarily induced by the presence of intense magnetic fields in this region. Observations conducted by imaging atmospheric Cherenkov telescopes have detected very high energy gamma-rays originating from a point source known as HESS J1745-290, situated in close proximity to the GC. This source is conjectured to be associated with the supermassive black hole Sagittarius A*. The GC region contains diverse structures, including molecular clouds and non-thermal filaments, which collectively contribute to the intricate magnetic field configurations in this region. By utilizing a magnetic field model specific in the GC region, we explore the phenomenon of photon-ALP oscillations in the gamma-ray spectrum of HESS J1745-290. Our analysis does not reveal any discernible signature of photon-ALP oscillations, yielding significant constraints that serve as a complement to gamma-ray observations of extragalactic sources across a broad parameter region. The uncertainties arising from the outer Galactic magnetic field models have minor impacts on our results, except for ALP masses around 10-7 eV, as the dominant influence originates from the intense magnetic field strength in the inner GC region.

The Halbach and alternating polarity linear magnets array are designed for microparticle separation, based on magnetophoresis

Abstract Particle separation using magnetophoresis requires an inhomogeneous magnetic field which affects the microparticle. The more changes in the magnetic field, the greater the magnetic force. The changes could exist in various ways. In this article, the change to produce a more intensive inhomogeneous magnetic field is generated by rotating the magnets to a specific degree. The analyses are done for three-state magnet arrays. For this purpose, a device is fabricated and the mentioned arrays are embedded in it. First, the results are simulated. The mathematical piecewise algorithm is used to validate the simulation. By examining the states in the fabricated device the experimental results are extracted. Overall, the results demonstrated that the Halbach and alternating polarity linear arrays (both 90, and 180 degrees) have better efficiency and throughput than the regular design array (without magnet rotating). The Halbach designs are illustrated with approximately the same results. However, in alternating polarity linear array, 180 degrees the particle capturing rate stood in a better place than the other design. 

Continuous‐wave and cavity‐dumped 1064 nm Nd:YVO4 laser based on the magneto‐optical effect

AbstractIn this paper, continuous‐wave and cavity‐dumped Nd:YVO4 lasers are studied. Firstly, through theoretical analysis and numerical simulation, the output characteristics of a continuous‐wave laser based on the magneto‐optical effect are analysed using the rate equation. The continuous adjustment of output power and pump threshold power is realised using the magneto‐optical effect to rotate the polarisation direction of laser. The theoretical simulation results show that the output power of the laser could be effectively controlled under different magnetic field intensities. On this basis, the authors explore the cavity‐dumped laser system based on the magneto‐optical effect. By adjusting the intensity of the magnetic field and rising edge time, the pulse width and waveform could be flexibly adjusted. The relationship between the magnetic field intensity in the low Q period and the spot radius of the pump and the signal beam and the output energy and the output pulse waveform is analysed. These research results lay a foundation for further optimising the design and application of magneto‐optical effect lasers.

Agenesis of the corpus callosum combined with cerebral abnormalities: Clinical and diagnostic features

Background. Agenesis of the corpus callosum (ACC) is the total or partial absence of CC, one of the most common congenital brain malformations, with an incidence rate of 1.4 cases per 10,000 live births. Aim. To describe the clinical and diagnostic features of 4 patients with ACC. Materials and methods. Four patients with ACC aged 11, 12, 13, and 50 years were managed, of whom 3 were males, and 1 was a 13-year-old girl. All patients underwent a neurological examination, which assessed cognitive and mental disorders and electroencephalography. Patients underwent magnetic resonance imaging (MRI) in standard modes using a magnetic resonance imaging scanner with a magnetic field intensity of 1.5 T to detect damage to the brain's anatomical structure. Results. The disease was asymptomatic in 2 patients (a 50-year-old man and a 12-year-old boy). In the other 2 cases, there was an apparent neurological and cognitive deficit. The boy's parents and grandparents died of chronic alcoholism at the age of 11. During a neurological examination, he showed signs of damage to the pyramidal tract, as well as pronounced cognitive impairment with profound mental retardation, including delayed psycho-speech development. The 13-year-old girl suffers from severe mental retardation with speech impairment. In both cases, ACC was associated with epilepsy with a seizure frequency ranging from 6 times a year in the girl and up to 15 times a month in the boy. The gross neurological and cognitive deficits cause social difficulties since such patients need rehabilitation and ongoing care. In all cases, the diagnosis of ACC is based on the results of brain MRI, which is the method of choice. MRI enables assessment of the CC anatomical structure and the presence of other brain abnormalities. Complete agenesis was established in 3 cases, including a girl, and in one patient – a 12-year-old boy – partial agenesis with intact splenium was detected. In all patients, agenesis was combined with brain congenital malformations, namely with the absence of the septum pellucidum, interhemispheric and porencephalic cyst, basilar invagination, and venous malformation of the frontal lobe. Conclusion. ACC is a rare congenital brain malformation. According to the data, agenesis is more common in males. Complete ACC was diagnosed in 3 patients and partial ACC in 1. Risk factors include maternal alcohol consumption during pregnancy. The clinical presentation is diverse: from an asymptomatic course to severe cognitive impairment with severe and profound mental retardation, epilepsy, and autistic disorders with neurological deficits, including damage to the pyramidal tract. The primary diagnostic method is MRI, which detects anatomical changes in CC and other brain structures.

Pengaruh Pengaruh Jenis Bahan Atap Terhadap Intensitas Medan Elektromagnetik ELF Oleh SUTET 500 KV

Based on initial observations, Kersikan Village is passed by the 500 kV SUTET transmission line which is very close to residents' homes. The purpose of this study is to analyze whether the type of roofing material and the distance of the study have an effect in reducing the intensity of the ELF electromagnetic field by the 500 kV SUTET. The type of research used is quantitative research using survey techniques. In this study, there are 2 dependent variables, namely ELF magnetic field intensity and ELF electric field intensity. Artificial houses are used to test the effect of roof type on ELF electromagnetic intensity. The research data was measured from morning to night and the measurement distance was getting farther from SUTET. Based on the results obtained, the intensity of the electric field and ELF magnetic field without a roof barrier around the SUTET decreased when compared to measurements under the roof and the biggest decrease occurred when under the galvalume roof. Measurements at a distance of 0 meters obtained greater intensity results than when measuring distances of 50 and 100 meters. The measurements in the morning produced a smaller magnetic field intensity and electric field than the measurements at night. So it can be concluded that there is an effect of roof type, distance and measurement time on the intensity of ELF electromagnetic fields around SUTET.

A COMPARATIVE STUDY OF QUADRUPOLE RAIL LAUNCHER AND TWO-WING ARMATURE ELECTROMAGNETIC LAUNCHER: MAGNETIC AND PERFORMANCE METRICS

This study presents a novel two-wing armature electromagnetic launcher design that aims to overcome the limitations of conventional quadrupole railguns. The proposed TWAEL system exhibits significantly enhanced magnetic field properties, achieving a 23-fold increase in magnetic flux density, an increase in magnetic field intensity, and a 1.6-fold increase in current density compared to the QRL under identical input conditions. Consequently, the TWAEL demonstrates a 6.7-fold greater electromagnetic co-energy storage capacity per unit volume, translating to substantially higher accelerative forces, reaching up to 18,045 N. Simulations validate the TWAEL's superior performance in terms of magnetic field characteristics and energy conversion efficiency, highlighting its potential as an advanced, high-performance electromagnetic propulsion system for various applications.

On the backward excursions in the free-swimming magnetotactic multicellular prokaryote 'Candidatus Magnetoglobus multicellularis'.

Magnetotactic bacteria align to magnetic field lines while swimming in a behavior known as magnetotaxis. They are diverse phylogenetically and morphologically and include both unicellular and multicellular morphologies. The magnetotactic multicellular prokaryote (MMP) 'Candidatus Magnetoglobus multicellularis' has been extensively studied, even though it remains uncultured up to now. It swims back and forth along magnetic field lines, exhibiting a preferential swimming direction that is usually south-seeking, as described for most magnetotactic microorganisms from the Southern Hemisphere. In order to understand the effects of the magnetic field intensity on the backward excursions of 'Ca. M. multicellularis', we applied magnetic fields ranging from 0.09 to 3.4 mT and recorded their movements. Each microorganism was followed frame by frame generating position coordinates, which were used to calculate the frequency of reversal events, as well as the time, distance, and velocity. The velocities in forward movements before and after backward excursions are similar, but no relation was found with the velocity in backward movements. The shapes of the trajectories are distinct in forward and backward movements. In addition, the backward velocities are usually higher. The sharp changes in direction (approximately 180°) indicate that reversal of the flagella rotation direction is the probable mechanism for swimming backward. In conclusion, the backward excursions provide additional freedom of movement to the microorganism, especially when it is constrained by magnetic fields stronger than the Earth's. Backward movements integrate the 'Ca. M. multicellularis' behavioral toolbox, which includes also negative phototaxis, photokinesis, magnetotaxis and possibly helical klinotaxis.

Vibration response of small-scaled FG-CNTRC sandwich plates with MR fluid core supported by Kerr elastic substance

The current work is a continuation of the previous work by proposing the refined zigzag theory (RZT) for the vibration response of the micro sandwich plate. The face sheets of this structure are magnetostrictive and reinforced with single-walled carbon nanotubes (SWCNT) in four different patterns (FG-AV, FG-O, FG-X, and UD) following the rule of mixtures (ROM). The core material contains magnetorheological (MR) fluid which can work as a damper under a magnetic field. The micro sandwich plate is supported by an elastic substance utilizing the Kerr model. Additionally, the modified couple stress theory (MCST) is employed to predict size effects, and the magnetostrictive material (MsM) properties are considered viscoelastic based on the Kelvin–Voigt model. The Hamilton principle is applied to derive the size-dependent equations of motion. Then, an analytical solution is presented to evaluate the efficacies of various parameters including the volume fractions and the functional arrangement of carbon nanotubes, the geometrical aspect ratio of the system, the magnetic field intensity, the type of MR fluid, the small-scale parameter, damping coefficients of the system, and the elastic medium. Consequently, 29% increase in the dimensionless frequency for [Formula: see text] is indicated when the small scale changes from [Formula: see text] to [Formula: see text]. This research can be contributed to the design and optimization of systems that use micro sandwich plates, addressing practical and essential engineering considerations.

Investigating the Link between Space-Weather Parameters and Forbush Decrease

The link between space-weather parameters and Forbush decrease has been investigated. The aim was to determine the relationship between space-weather parameters and forbush decrease. Daily cosmic ray counts from MGDN station for 2010-2015 were used to achieve this aim. Solar wind speed (SWS) and interplanetary magnetic field (IMF) intensity were equally used as space-weather parameters. The semi-automated method of FD detection was deployed. This method generated 1104 FDs for the MGDN station within the years under study. A correlation and regression between FDs and space-weather parameters (SWS and IMF) were further tested. The results of the correlation and regression are statistically significant. The implications of the present space-weather data on FDs are highlighted.

Identifying Infant Body Position from Inertial Sensors with Machine Learning: Which Parameters Matter?

The efficient classification of body position is crucial for monitoring infants' motor development. It may fast-track the early detection of developmental issues related not only to the acquisition of motor milestones but also to postural stability and movement patterns. In turn, this may facilitate and enhance opportunities for early intervention that are crucial for promoting healthy growth and development. The manual classification of human body position based on video recordings is labour-intensive, leading to the adoption of Inertial Motion Unit (IMU) sensors. IMUs measure acceleration, angular velocity, and magnetic field intensity, enabling the automated classification of body position. Many research teams are currently employing supervised machine learning classifiers that utilise hand-crafted features for data segment classification. In this study, we used a longitudinal dataset of IMU recordings made in the lab in three different play activities of infants aged 4-12 months. The classification was conducted based on manually annotated video recordings. We found superior performance of the CatBoost Classifier over the Random Forest Classifier in the task of classifying five positions based on IMU sensor data from infants, yielding excellent classification accuracy of the Supine (97.7%), Sitting (93.5%), and Prone (89.9%) positions. Moreover, using data ablation experiments and analysing the SHAP (SHapley Additive exPlanations) values, the study assessed the importance of various groups of features from both the time and frequency domains. The results highlight that both accelerometer and magnetometer data, especially their statistical characteristics, are critical contributors to improving the accuracy of body position classification.

Direct measurements of the conventional and rotational magnetocaloric effects in Gd thick films

Abstract Magnetic refrigeration (MR) offers a sustainable and emission-free solution to the prevalent heat-pumping systems used worldwide. Typically, it utilizes the magnetocaloric effect (MCE) to achieve cooling by changing the external magnetic field intensity. However, an alternative approach involves maintaining a fixed field intensity while manipulating its orientation to induce temperature changes, in an effect known as the rotating MCE (RMCE). While the RMCE has been extensively studied in materials with magnetocrystalline anisotropy, its investigation in polycrystalline magnetocaloric samples with asymmetric shapes has been lacking until recently. In this case, the RMCE is induced by the demagnetizing effect, which becomes more pronounced in high aspect-ratio sample geometries exhibiting different effective demagnetizing factors at different orientations, such as in films. In this work, we characterize the conventional and rotational MCE of 40 μm-thick gadolinium films through magnetization and direct temperature measurements. The maximum adiabatic temperature change achieved under a 1 T magnetic field was 2.05 K when the film was oriented in plane with the field and 1.25 K when the film was perpendicular to the magnetic field, corresponding to an adiabatic temperature difference of around 0.8 K which may be induced through magnetic field rotation. Additionally, the maximum adiabatic temperature change upon rotation is shown to exhibit a non-monotonous behavior with field intensity, displaying a peak value for field intensities of around 0.8 T. The high aspect ratio of the Gd film has been demonstrated to considerably enhance the intensity of demagnetizing field-based RMCE compared to bulk samples, paving the way for future research in this emerging field of MR cooling.

An induction curing technique for CFRP laminate via magnetic particle‐induced in situ heating

AbstractCuring high‐performance carbon fiber reinforced polymer (CFRP) structures with economical and energy‐efficient off‐oven techniques is important for the widespread application of the composite. In this work, we reported a magnetic particle‐induced in situ heating method to controllably cure CFRP laminates with stacking sequences of [0]8, [0/90]4s and [0/45/90/−45]2s. Results showed that all the laminates can undergo a consistent, layup‐independent two‐staged heating protocol via regulating the magnetic field intensity. Under the same curing protocol, the three stacking‐sequenced CFRP laminates can be cured more completely under induction heating than oven heating, in addition to a moderately improved tensile and flexural properties. However, the porosity of the laminates slightly increased under induction heating. The proposed new curing method provides a new avenue to the fabrication of advanced CFRP composite structures without oven or autoclave.Highlights A particle‐induced in situ heating method to controllably cure carbon fiber reinforced polymer (CFRP) laminates was proposed. This method was capable to cure CFRP laminates with different stacking sequences. Mechanical property of laminates was moderately improved under this method.

Study on the Characteristics of Turn-to-Turn Short Circuit Faults in the Primary Windings of the Generator Terminal Voltage Transformer

Turn-to-turn short circuit faults in the primary winding of generator terminal voltage transformers can lead to erroneous operation of stator grounding protection systems. This paper analyzes the fault characteristics associated with such failures and derives formulas for the fault phase current and zero-sequence voltage during a turn-to-turn short circuit in the primary winding. A 3D finite element model of the generator terminal voltage transformer is established by using Altair Flux 3D, and the accuracy of the model is verified. Based on this model, simulation tests were conducted to investigate turn-to-turn short circuits in the primary winding. The results reveal that as the number of shorted turns increases, the voltage of the fault phase decreases continuously while the voltages of the other two phases increase. The current in the short-circuited phase rises significantly, accompanied by an increase in zero-sequence voltage. Visualizations of magnetic field parameters indicate that as the number of shorted turns increases, the magnetic induction magnitude of the fault phase rises steadily and approaches saturation, resulting in heightened magnetic field intensity near the shorted turns. This analysis of fault characteristics through simulation contributes to the advancement of fault diagnosis systems for generator terminal voltage transformers.

Biological and physicochemical effects of magnetic field on <em>Artemia franciscana</em> exposed to cyanobacteria extract and treated with isotherapeutic 200cH

This study proposes an experimental model to analyze homeopathic potencies' biological and physicochemical effects on intense magnetic fields. The proposed model is based on the exposition of Artemia franciscana cysts to saxitoxin (cyanobacteria extract) and the treatment with R. raciborskii extract isotherapic 200cH (named saxitoxin 200cH), followed by the hatching and nauplii (larvae) vitality rate (live nauplii/total cysts), and the gene expression of heat shock proteins (HSP 26, 40, 90, and p26), as previously described ad bio-resilience indicators [1,2]. In a second experiment, pH, conductivity, and temperature temporal curves were built, and different treatments were compared before and after being poured into the seawater. The method details are as follows: Artemia franciscana cysts were seeded into artificial seawater in 96-well plates in triplicate, exposed immediately to 25ppm of R. raciborskii extract, and treated with sterile purified water (SPW), succussed SPW (vehicle controls), or saxitoxin 200cH prepared in SPW, submitted or not to a 2400 Gauss static magnetic field for 15 minutes. Plates were kept in a Faraday cage under stable lightening (300 mini-led lamps), temperature (26.5%), humidity (65%), and magnetic field (0.7 µT). The hatching and vitality rate were analyzed after 48 hours. In the second experiment, the physicochemical parameters were analyzed before and after one minute, two, and 24 hours after pouring the samples into seawater (100µL/100mL), kept at the same environmental conditions set for the first experiment. The statistical analysis was made by two-way ANOVA / Tukey, with α=0.05. Treatment of cysts with SPW alone reduced the hatching and nauplii vitality rate in relation to the other treatments (p≤0.05); however, the treatment with saxitoxin 200cH exhibited smaller variance and the highest statistical hatching (p=0.0009) and vitality (p=0.0007) levels. The previous submission of samples to the magnetic field reverted this result by canceling the statistical differences and increasing the variance of saxitoxin 200cH datapoints. The analyses of HSP gene expression are still in course. In the second experiment, there is no specific effect of saxitoxin 200cH on temperature, conductivity, and pH, independent of the exposition of samples to the magnetic field. The results corroborate the hypothesis that a possible interference on dipolar dynamics of saxitoxin 200cH caused by the intense magnetic field could negatively interfere with its biological effect independently of eventual changes in temperature, conductivity, and pH in the seawater, although its clear capacity to improve tracking homeopathic potencies in water when using the method of solvatochromic dyes, as previously shown [3].

Enantioseparation of antihistamines using magneto-thin-layer chromatography: The effects of various orientations and intensities of magnetic fields

The effect of magnetic fields produced by magnet and solenoid was investigated for the first time in the enantioseparation of antihistamines using thin-layer chromatography. The racemic mixtures of cetirizine and hydroxyzine were selected as the model drugs for studying the magnetic field effect on enantioseparation. The magnets were fixed to a U-shape blade that rotated around the separation chamber by a motor to apply a magnetic field perpendicular to the direction of mobile phase movement. Also, the separation chamber was positioned within a solenoid, and an electric current was utilized to apply the magnetic field in a parallel direction to the mobile phase movement. L-arginine was added to the mobile phase as a chiral selector to perform the enantioseparation of drugs. When magnets generate the magnetic field, both in attraction and repulsion, the spots become broader and the peak height decreases as the magnetic field intensity and rotation speed of the magnets increase. An increase in peak height was observed in the presence of the magnetic field generated by + 3.25A current in the solenoid. Regardless of the type of applied magnetic field, the retention factor values exhibited slight reductions. It was observed that separated enantiomers were similarly affected by various magnetic fields. The distribution coefficient, mass transfer, equilibrium, and lipophilicity were all potentially influenced by the magnetic field, which could explain the alterations.

Juno Observations Set New Constraints on the Electrodynamic Interaction Between Io and Jupiter.

Juno's highly elliptical polar orbits provide unprecedented in-situ observations of the electrodynamic interaction between Jupiter and its volcanic moon Io. These observations occur in regions never sampled before both near Io's orbit and near Jupiter's ionosphere and at distances between the two. Magnetic field data obtained during multiple traversals of magnetic field lines mapping to Io's orbit reveal remarkably rich and complex magnetic signatures near flux tubes connected to Io's orbital position. Here we present a methodology to model the distribution of currents along Io's flux tube (IFT) and Alfvén wings in such a way as to match the magnetic field signature observed during Juno's traversals of the IFT and Alfvén wings downstream of Io. We obtain the location, size and morphology of the current-carrying region as well as the distribution of currents within the IFT and Alfvén wings. The observed field-aligned currents exhibit strong filamentation, with upward and downward currents splitting into secondary cells rather than forming uniform structures. Additionally, there is a strong correlation between total field-aligned current intensity, particle energy flux, and Poynting flux, indicating efficient energy transfer and coupling in the Jupiter-Io system. Using all of Juno's traversals up to perijove (PJ) pass 42, we estimate the strength of the interaction with regards to distance along Io's extended tail, Io's position in the plasma torus and the magnetic field intensity at the footprint in Jupiter's ionosphere, illuminating the interaction of Jovian magnetospheric plasma with Io and setting important constraints in the Io-Jupiter interaction.

Numerical simulations of MHD effect on convective heat transfer characteristics in bubbles coalescence process

In this numerical study, the coalescence characteristic of a coaxial bubble pair and its influence on the liquid-to-wall convection heat transfer are investigated under different magnetic field intensities, magnetic field directions, and wall confinement ratios by adopting the volume of fluid (VOF) method. The results reveal that in the direction of heat flow, the toroidal vortices around the bubbles are dampened and even vanish completely after applying the spanwise magnetic fields, while the toroidal vortices only get away from the hot wall in the presence of the transverse magnetic fields. Correspondingly, the convective heat transfer on the hot wall is suppressed to varying degrees under the magnetic fields in different directions. The inhibitory action of the magnetic field on the heat transfer becomes stronger with the decreasing separation distance (s*) between the coaxial bubbles. The total increment of heat transfer (Nu*) is a decreased function of Hartmann number (Ha) and that decreased amplitude of Nu* under the spanwise magnetic field is nearly twice that of the transverse magnetic field. Additionally, the variations of Nu* are independent of the wall confinement ratio (Cr) for Ha < 400, while the Cr has an obvious effect on Nu* for Ha > 400 and the values of Nu* are considerably smaller at a larger Cr. The results about the effect of the magnetic field and wall confinement on the two-phase heat transfer can be referenced in the cooling system design of fusion reactor.

Research on propagation characteristics of an electromagnetic wave in magnetized fully ionized dusty plasma

When some spacecraft fly at high speed in near-earth space, the dusty plasma is attached to the surface of the spacecraft due to the intense friction between the spacecraft and the space. The dusty plasma attached to the aircraft hinders the propagation of electromagnetic (EM) waves and affects the flight safety of the pilot. In this paper, we replace the collision term of the general Boltzmann equation with the Fokker-Planck-Landau collision term and obtain the general correlation expression of the electron distribution function in the fully ionized dusty plasma. The dielectric relation of EM waves in magnetized fully ionized dusty plasma is calculated considering the impact effect and charging effect of dust particles in the case of an external magnetic field. The reflection coefficient (R) and transmission coefficient (T) of the EM wave in magnetized fully ionized dusty plasma are calculated by a scattering matrix method. The effects of applied magnetic field intensity and dust particle parameters on the propagation characteristics of EM waves in magnetized fully ionized dusty plasma are discussed by simulation. In addition, the propagation characteristics of EM waves in ordinary plasma and magnetized fully ionized dusty plasma are compared. The results show that with the increase in the additional magnetic field, the reflection of the EM wave in the fully ionized dusty plasma decreases and the transmission increases. In the 0–100 GHz band, dust particles block EM waves from penetrating fully ionized dusty plasma. Other dusty plasma parameters also affect the propagation characteristics of EM waves to varying degrees. These results provide a theoretical reference for solving the communication related problems of high-speed aircraft.