Addition Of Magnetic Field Research Articles

MICROSTRUCTURE AND PROPERTIES OF 6082/7075 MAGNETIC-FIELD-ASSISTED RESISTANCE-SPOT-WELDED JOINTS

To advance automotive lightweighting, a study was conducted on steady-state magnetic-field-assisted resistance spot welding of 6082 aluminum alloy (1.0 mm thick) and 7075 aluminum alloy (1.5 mm thick) with thermal compensation. The influence of varying magnetic induction intensity on the microstructure and tensile properties of welded joints was assessed under the same welding current, time and electrode pressure. The results revealed that the Lorentz force induced by magnetic induction intensity ranging from 0 mT to 60 mT could promote an outward circumferential movement of molten metal within the weld nugget. This movement, at the same time, led to an increase in the weld-nugget size and improved the efficiency of thermal resistance. At a magnetic induction intensity of 80 mT, no weld-nugget formation occurred in the welded joint. Microstructural observations at magnetic induction intensities of 0 mT and 60 mT revealed equiaxed grains at the nugget center and columnar dendrite grains at the nugget edge in the welded joints. The Lorentz force accelerated the weld cooling rates after the addition of magnetic field, refining the weld grain structure. Tensile properties of the welded joints gradually improved with increasing the magnetic induction intensity from 0 mT to 60 mT, driven by the weld nugget size expansion and weld grain refinement. Overall, the present study indicated that the magnetic induction intensity of 60 mT resulted in the most favorable comprehensive mechanical properties of the investigated welded joints.

Improvement of gelation properties of Penaeus vannamei surimi by magnetic field-assisted freezing in combination with curdlan

Traditional methods of freezing and thawing may harm the quality of meat products. In order to reduce the negative impact of freezing on surimi products, the magnetic field-assisted freezing method is combined with various curdlan ratios to enhance the gelation characteristics of Penaeus vannamei surimi in this study. The results showed that the magnetic field-assisted freezing technique significantly improved the quality of thawed surimi compared with soaking freezing (SF), whereas the addition of curdlan further improved the gelation properties, and the gel strength, water-holding capacity, textural properties, whiteness, and G′ value were significantly improved when its content was increased to 0.6 %. However, excessive amounts of curdlan interfered with protein covalent cross-linking, leading to a decrease in gel quality. Additionally, the addition of magnetic field and curdlan encouraged the shift of the α-helix to the random coil and β-sheet transition, which stimulated the growth of myofibril molecules, exposed the hydrophobic groups and thiols, improved protein-molecule interactions, and promoted systematic gathering of proteins, leading to the formation of the microstructure of dense and small pores. It also resulted in a drop in water release, an increase in the proton density and a shift in the water condition from free water to more immobile water, which had higher sensory qualities. These effects together resulted in a reduction in thawing and cooking loss to 11.41 % and 13.83 %, respectively. These results also help to clarify the gelation process of shrimp surimi and help to regulate the gelation characteristics of shrimp surimi products.

Study on Fluidization Characteristics of Magnetically Fluidized Beds for Microfine Particles

The bed pressure drop, minimum fluidized gas velocity, bed density, and bed expansion rate are important parameters characterizing the fluidization characteristics of gas-solid fluidized beds. By analyzing these parameters, the advantages and disadvantages of the fluidization state can be known. In this study, experiments were conducted to study the fluidization characteristics of a gas-solid magnetically fluidized bed for microfine particles by changing the magnetic field strength, magnetic field addition sequence, and static bed height. The experimental results show that when the magnetic field strength increased from 0 KA/m to 5 KA/m, the minimum fluidized gas velocity of particles increased from 4.42 cm/s to 10.32 cm/s, while the bed pressure drop first increased and then decreased. When the magnetic field strength is less than 3.4 KA/m, the microfine particles in the bed are mainly acted on by the airflow; while when the magnetic field strength is greater than 3.4 KA/m, the microfine particles are mainly dominated by the magnetic field. The magnetic field addition sequence affects the fluidization quality of microfine particles. The fluidized bed with ‘adding magnetic field first’ shows a more stable fluidization state than ‘adding magnetic field later’. Increasing of the static bed height reduces the bed expansion rate. The bed expansion rate is up to 112.5% at a static bed height of h0 = 40 mm and H = 5 KA/m. This will broaden the range of density regulation of a single magnetic particle and lay the advantage of gas-solid magnetically fluidized bed for microfine particles in the field of separation of fine coal.

Exploring the effect of attractive and repulsive magnetic field on electricity generation and microbial community in microbial fuel cells

External magnetic field technology enhances microbial electrochemical reactions in biological processes. This study added Neodymium-Iron-Boron magnets to the outside of a double-chamber cubic microbial fuel cell (MFC) to explore the attractive or repulsive magnetic field effects at various intensities (0, 60, and 120 mT) on MFC performance. The results show that an extra 120 mT repulsive magnetic field can generate a peak power density of 144 mW/m2 and a maximum current density of 1558 mA/m2. This value is 45 and 8 times higher, respectively, compared without adding the magnetic field. Moreover, adding 120 mT repulsive magnetic field can increase coulombic efficiency (CE) to 63.0%, which is higher than the CE of 25.9% without magnetic field addition. Taxonomy profiling classification results show that Geobacter and Pseudomonas, which can achieve e-pili and redox mediators, were the domain microorganism community. Magnetic fields enhance the electron movement efficiency through extracellular electron transfer mechanisms, including e-pili and redox mediators provided by the exoelectrogenic microorganism to enlarge the chemical oxygen demand removal efficiency and CE value as well as increase the electron transfer probability to the electrode.

Effect of magnetic field waveform on microstructure and properties of laser cladding

Ni60 coating-45 steel substrate was prepared by magnetic field assisted laser cladding with four waveforms:steady magnetic field (SMF), alternating magnetic field (AMF), pulsed magnetic field (PMF). The effects of four kinds of magnetic fields on the morphology, microstructure, phase composition and microhardness of the coating were studied, and the magnetic field mechanism on the coating was briefly analyzed. Results revealed that the addition of magnetic field can significantly reduce the number of cracks, facilitate grain refinement and improve the coating hardness. The improvement degree of four kinds of magnetic fields on the coating performance is: PMF > APMF > AMF > SMF. Among them, the coating performance is prominently improved by PMF, but there is a serious segregation of hard phase; The segregation of hard phase and the slender of the structure occur in the APMF.

MHD hybrid nanofluid flow comprising the medication through a blood artery

The current study focuses on the laminar flow of copper and copper oxide ({text{Cu/blood}} and {text{Cu}} + {text{CuO/blood}}) hybrid nanoliquid, considering blood as a carrier fluid in a rectangular domain between two permeable channels. This study may manipulate for the purpose such as the drug delivery process, flow dynamic mechanism of the micro-circulatory system. In the proposed model, MHD and heat source/sink on the flow pattern have been studied. Furthermore, the sides of each channel are permeable, allowing the nanoliquid to escape, filter, squeezing and dilating with a fixed velocity. Appropriate transformations are incorporated to convert the governing partial differential equations and the boundary conditions suitable for computation. The elegant homotopy analysis method (HAM) is used to obtain analytic approximations for the resulting system of nonlinear differential equations. The features of flow characteristics such as velocity, and temperature profiles in response to the variations of the emerging parameters are simulated and examined with a physical explanation. The magnetic field plays a vital role in the blood flow and therefore the existing literature has been extending with the addition of magnetic field. Among the many outputs of the study, it is found that the pressure distribution decline with the accumulated values of the magnetic parameter at the center of the flow regime. The augmentation in the temperature distribution estimates the pH values and electric conductivity. Therefore, the {text{Cu}},,{text{and}},,{text{CuO}} hybrid nanofluids are used in this study for medication purposes. The magnetic field has an important role in the blood flow and therefore the extending study has been extending using the magnetic field. The heat emission/absorption term is added to the energy equation to maintain the homogeneous temperature for the blood flow. We expect that this work will provide efficient outputs for medical purposes such as drug delivery.

Finite density effects on chiral symmetry breaking in a magnetic field in 2+1 dimensions from holography

In this work, we study finite density effects in spontaneous chiral symmetry breaking as well as chiral phase transition under the influence of a background magnetic field in $2+1$ dimensions. For this purpose, we use an improved holographic soft wall model based on an interpolated dilaton profile. We find inverse magnetic catalysis at finite density. We observe that the chiral condensate decreases as the density increases, and the two effects (addition of magnetic field and chemical potential) sum up, decreasing even more the chiral condensate.

Magnetic field and ultrasonic aided laser drilling effect on Ti6Al4V microstructural characteristics

ABSTRACT Today, the utilization of millisecond pulse laser drilling, despite the extensive applications in different fields, is accompanied by several limitations such as low penetration depth, high thickness of recast layer, and heat-affected zone. In order to overcome these limitations, different techniques such as applying magnetic field as well as utilizing ultrasonic vibrations have been proposed. Up to now, limited investigations have been conducted regarding the effect of simultaneous addition of magnetic field and ultrasonic vibration on microstructural characteristics; therefore, in this paper, the simultaneous effects of magnetic field (0.5 Tesla intensity) and ultrasonic vibrations (with the frequency of 28 kHz and amplitude of 15 μm) on the formed phases, recast layer and heat-affected zone thickness have been studied in laser drilling of Ti6Al4 V. According to the results, 23.53% and 6.31% reductions were obtained in diameter and depth of the drilled hole compared to conventional laser drilling, respectively. Moreover, the diameter of heat-affected zone, in the inlet of the drilled hole, was reduced by 30.33% in this hybrid process compared to conventional laser drilling. Besides, it was observed that the presence of ultrasonic vibrations prevents from the formation of acicular α structure in the recast region of Ti6Al4 V.

Effect of magnetic field on the performance of a deep eutectic solvent-based redox flow battery from polarization perspective

In recent years, with the promotion of global renewable energy, the introduction of energy storage batteries has become more and more important. Redox flow battery has attracted more and more attention due to their environmental friendliness, safe and reliable operation. This work studies the effect of different magnetic field intensities and the duration of magnetic field addition on the mass transfer and electrochemical reaction process of iron-vanadium ions in deep eutectic solvent (DES). At the same time, the effect of magnetic field on the polarization performance of DES-based redox flow battery is also studied. The experimental results show that the iron and vanadium DES electrolytes increase their redox peak current density under the action of adding magnetic field. The test of the polarization performance of the DES-based redox flow battery shows that the addition of magnetic field can reduce the area specific resistance (ASR) of the battery and improve the polarization performance of the battery.

Enhancement of material removal rate in magnetic field-assisted micro electric discharge machining of Aluminium Matrix Composites

Micro-electrical discharge machining (Micro-EDM) is a micro-machining process in which miniaturised and precision parts/components are manufactured with good dimensional accuracy and fine surface finish. The present work investigates the effect of magnetic field-assisted Micro-EDM of Aluminium Matrix Composites with a Tungsten electrode using the Response Surface Methodology (RSM). Experiments are conducted based on RSM based central composite design. The process parameters considered for this study are voltage, capacitance and feed rate. The material removal rate (MRR) is considered as the output process parameter. The response surface-based mathematical model is developed for MRR. The model is statistically significant and all the three machining parameters and interaction effects are also significant on the MRR. Experimental investigation shows that the addition of magnetic field in Micro-EDM increases the MRR. Finally the predicted values and experimental values are validated by confirmation experiments.

Effect of magnetic field on denitrification of anaerobic ammonia oxidation

In this experiment, the effect of magnetic field on the denitrification efficiency of anammox reactor was studied to solve the problems such as slow start-up of anammox process and environmental sensitivity by adding magnetic particles (adding amount 0 20 60 100g/L) in the reactor. It was found that the addition of magnetic field could improve the activity of partial nitrification bacteria, accelerate the accumulation of nitrite and promote the anaerobic ammonia oxidation reaction, especially when the magnetic particle dosage was 60 g/L. The presence of magnetic field can enhance the activity of anaerobic ammonia oxidizing bacteria, increase the impact load resistance of anaerobic ammonia oxidizing system, improve denitrification efficiency and shorten hydraulic retention time.

INVESTIGATION ON THE DEPOSITION RATES OF ELECTROLESS Ni–P/NANO-SiC PLATING WITH THE ASSISTANCE OF ELECTROMAGNETIC FIELDS

The nano-SiC/Ni–P composite coatings (nSNCCs) were fabricated on the surface of Glass substrates with the assistance of different electromagnetic fields. Then, the deposition rates of the nSNCCs were calculated by the weighing method. Morphology, chemical composition and crystal structure were characterized by SEM, EDS and X-ray diffraction (XRD), respectively. Experimental results show that the nSNCCs are all built by the accretion of spherical co-deposition product of Ni solid solution and nano-SiC particulates. Moreover, at the same plating time, the deposition rates of the nSNCCs increase with the increasing magnetic strength, and reach the peak by 17.5[Formula: see text]g/h[Formula: see text]m[Formula: see text]. Meanwhile, the spherical particle size and the spaces between spherical co-deposition decrease, which result in the formation of the dense layers. The addition of magnetic fields in preparation process not only promotes the deposition of the nSNCCs, but also has a great influence on the orientation of the deposited products, which is favorable for the formation of a compact and uniform composite coating.

Weak magnetic field: A powerful strategy to enhance partial nitrification

Partial nitrification (PN) combined with anaerobic ammonium oxidation process has been recognized as a promising technology for the removal of nitrogenous contaminants from wastewater. This research aimed to investigate the potential of external magnetic field for enhancing the PN process in short and long term laboratory-scale experiments. Different strength magnetic fields (0, 5, 10, 15, 20 and 25 mT) were evaluated in short-term batch tests and 5 mT magnetic field was found to have better ability to increase the activities of aerobic ammonium oxidizing bacteria (AOB) of PN consortium. Long-term effect of magnetic field on PN consortium was studied with 5 mT magnetic field. The results demonstrated that the positive effect of magnetic field on PN process could also be testified at all of the four stages. Furthermore, a decrease of bacterial diversity was noted with the increase of magnetic field strength. Relative abundance of Nitrosomonadaceae decreased significantly (p < 0.01) from 13.9% in RCK to 12.9% in R5mT and 5.5% in R25mT. Functional genes forecast based on KEGG database indicated that the expressions of functional genes related to signal transduction and cell motility in 5 mT environment were higher expressed compared with no magnetic field addition and high magnetic field addition. The existence of 5 mT magnetic field didn't increase the abundance of AOB but increased the activity of AOB by increasing the rate of free ammonia into the interior of microbial cells. Addition of magnetic field couldn't change the final state of PN process according to the hypothesis proposed in this article. These findings indicated that the weak magnetic field was useful and reliable for the fast start-up of PN process since it was proved as a simple and convenient approach to enhance AOB activity.

The effectiveness of a magnetic field in increasing hydrogen production by water electrolysis

ABSTRACTHydrogen production by water electrolysis is one of the promising ways for sustainable energy. The influences of magnetic field on the covering ratio and the upward velocity of the bubbles during water electrolysis in different working conditions are investigated by the use of a high-speed camera. Results show that the upward moving velocities of bubbles are increased while the covering ratios of bubbles are increased, under different inter-electrode distances and current density under the magnetic effect. The bubbles are more uniformly distributed on the electrode and the corresponding averaged diameters are decreased. At an inter-electrode distance of 2 mm and current density of 0.3 A/cm2, the bubble flow rate is increased by 67.8% as the magnetic field is added, while it is about 42.0% at an inter-electrode distance of 5 mm and current density of 0.3 A/cm2. Without extra energy consumption, the addition of magnetic field to increase the efficiency of hydrogen production by water electrolysis is proved.

TH-AB-BRA-09: Stability Analysis of a Novel Dose Calculation Algorithm for MRI Guided Radiotherapy

Purpose: To determine the iterative deterministic solution stability of the Linear Boltzmann Transport Equation (LBTE) in the presence of magnetic fields. Methods: The LBTE with magnetic fields under investigation is derived using a discrete ordinates approach. The stability analysis is performed using analytical and numerical methods. Analytically, the spectral Fourier analysis is used to obtain the convergence rate of the source iteration procedures based on finding the largest eigenvalue of the iterative operator. This eigenvalue is a function of relevant physical parameters, such as magnetic field strength and material properties, and provides essential information about the domain of applicability required for clinically optimal parameter selection and maximum speed of convergence. The analytical results are reinforced by numerical simulations performed using the same discrete ordinates method in angle, and a discontinuous finite element spatial approach. Results: The spectral radius for the source iteration technique of the time independent transport equation with isotropic and anisotropic scattering centers inside infinite 3D medium is equal to the ratio of differential and total cross sections. The result is confirmed numerically by solving LBTE and is in full agreement with previously published results. The addition of magnetic field reveals that the convergence becomes dependent on the strength of magnetic field, the energy group discretization, and the order of anisotropic expansion. Conclusion: The source iteration technique for solving the LBTE with magnetic fields with the discrete ordinates method leads to divergent solutions in the limiting cases of small energy discretizations and high magnetic field strengths. Future investigations into non-stationary Krylov subspace techniques as an iterative solver will be performed as this has been shown to produce greater stability than source iteration. Furthermore, a stability analysis of a discontinuous finite element space-angle approach (which has been shown to provide the greatest stability) will also be investigated. Dr. B Gino Fallone is a co-founder and CEO of MagnetTx Oncology Solutions (under discussions to license Alberta bi-planar linac MR for commercialization)

Effect of magnetic field on the gas-jet boosted radio frequency glow discharge atomic emission spectrometry

The effect of a magnetic field on the radio frequency (rf) powered gas-jet boosted glow discharge (GD) source was investigated. The fundamental characteristic study includes the effects of discharge power of 10–50 W, and pressures range from 2 to 7 torr, on dc bias potential, sample weight loss rate and emission intensity with and without magnetic field. The bias potential and sample weight loss do not change with pressure above approximately 4 torr; however, as the pressure is dropped below approximately 4 torr there is a significant decrease in the bias potential and sample weight loss with addition of the magnetic field, while significant enhancement in signal intensity was observed with the addition of magnetic fields using Cu samples at 40 W, 200 ml/min gas flow rate and 5 torr pressure. The Cu(I) 324.7-nm and Cu(I) 327.4-nm wavelengths were enhanced as much as three times, while one order of magnitude enhancement was observed at the Cu(II) 224.7-nm wavelength. These results show that a magnetic field in this system only enhanced the excitation of sputtered atoms, and not on the sputtering. Both magnetic and non-magnetic boosted rf-GD shows a short-term precision of <1% RSD and long-term stability of <5% RSD for both major and trace element lines. Calibration curves are linear over 3–4 orders of magnitude with a general improvement of linearity by ratioing the signal to an internal standard of the matrix in both systems. Limits of detection for magnetic boosted GD are tens part per billion from many trace elements in low alloy steel which is an order of improvement over conventional rf-GD system.

Advances in the efficient generation of intense pulsed proton beams

Recent studies on the space−charge−limited reflex vacuum triode pulsed ion accelerator show a marked improvement in the output parameters and efficiency of the device. In the current machine, a 50−nsec pulse of 130−keV protons of 6000 A is produced at a current density of 20 A/cm2. Energies up to 300 keV have been investigated. The troide efficiency, defined as proton energy output versus total energy input, has been raised from 10 to 42% by the addition of magnetic fields that prevent anomalous electron loss in the fringing fields at the edges of the electrodes. Time−of−flight measurements confirmed the peak energies. The beam was measured to have about a 10 ° half−angle of spread. The results obtained indicate that the accelerator may be scaled to the ranges of parameters currently achieved by pulsed electron accelerators.