Magnetic Flux Intensity Research Articles

Total separation of multi-plastic wastes using magnetic levitation with adjustable sensitivity

Novel separation method with high efficiency is of great significance for mechanical recycling mixed waste plastics plays. However, the efficiency of most extant methods is restricted by their shortage that the methods can only deal with binary mixtures. In this paper, a novel magnetic levitation (MagLev) separation method based on scaled-up MagLev device is proposed to handle multi-plastics. A theoretical model on distribution of magnetic flux intensity and levitation conditions is established to guide the design of separation process. Based on the theoretical analysis, different processes for separation of multi-plastics with different purpose can be realized. The high sensitivity allows the separation of plastics with similar appearances (e.g. transparent plastics like polycarbonate and polymethyl methacrylate) and densities (difference with 0.01 g/cm3). The adjustable distribution of magnetic field changes the levitation condition of the waste plastics. Thus, the sequential separation of multi-plastics and extraction of target material from multi-plastics mixture are successfully addressed. The experiments demonstrate that the purities of separated multiple plastics reach to approx. 100 %. Furthermore, additional advantages of low cost and no energy consumed in separation process make the method a promising solution for economically-viable and environmentally-friendly mass production procedure.

Effect of magnetic and electric treatments on growth, yield and seedling parameters of chickpea (Cicer arietinum L.)

The objective of this work was to investigate the impact of electric current and magnetic field to the growth, yield, and seedling characteristics of chickpea by examining the response of chickpea to magnetic and electric treatments of varying intensities and durations. The ICC 30-70 seeds were obtained from the Department of Genetics and Plant Breeding and subjected to treatments involving AC magnetic flux intensities ranging from 75 mT to 125 mT for 3 and 5 minutes in the magnetic field, as well as AC electric current ranging from 75 mA to 125 mA for 30, 60, and 90 seconds treatments, separated by equal rest periods. Throughout the study, statistically significant differences were found in field emergence (84.30%), leaf area (8.62cm2), plant height (35.60cm), biological yield (10.70gm), number of pods per plant (30), and total yield per plot (118.67gm). Within the seedling parameters, all treated seeds exhibited the highest germination percentage compared to the control. Additionally, there was a favorable impact on seedling length (27.85cm), fresh weight (0.74gm), dry weight (0.30gm), and vigour indices I (2683) and II (28.71) following the seed treatment. The present study leads to the conclusion that the magnetic and electric treatments shown superior performance when compared to the control. Throughout the investigation, it was noted that the application of magnetic and electric treatments positively influenced the vegetative growth of plants. Furthermore, the dry matter partitioning showed a substantial rise in seeds treated with electric current, leading to a higher yield-per plot.

Investigating the Impact of Circular Sector Pole Head Structure on the Performance of a Multipole Magnetorheological Brake

The magnetorheological brake (MRB) epitomized a revolutionary modification in the braking systems because of its extremely efficient and well-controlled performance. To increase the safety and controllability of automotive braking system, researchers have developed a different MRB structures. Although much research on magnetorheological brakes has shown positive results in terms of brake torque, braking time, thermal efficiency, etc., the ability to increase braking force by expanding the disc surface, through which the magnetic field operates in a compact structure, is restricted. To address this issue, a new multipole MRB configuration with a unique pole head design that maintains compactness. Initially, the conceptual design was achieved by leveraging the combined impact of the twin disc-type structure and multipole concept. The model was used in a dynamic simulation to show how the braking torque of a magnetorheological braking system varies with coil current. The effects of circular sector pole head shape on braking performance were investigated using COMSOL Multiphysics software (version 5.5). A three-dimensional electromagnetic model of the proposed MRB was developed to examine the magnetic flux intensity and the impact of magnetic field dispersion on the proposed pole head structure of a magnetorheological brake. Based on simulation results, the circular sector pole head configuration is capable of increasing the active chaining regions for the MR fluid on the rotor surface, allowing for a more effective use of magnetic flux throughout the whole surface of a rotating brake disc, thereby increasing the magnetic field usage rate. The acquired simulation results show an increase in braking torque while keeping a compact and practical design structure.

Motor magnetic field analysis using the edge-based smooth finite element method (ES-FEM)

This paper proposes a smooth finite element method (S-FEM) for efficient and accurate analysis of motor magnetic fields. The edge-based smooth finite element (ES-FEM) formulations are derived for two-dimensional triangular element meshes suitable for multi-material motor structures, and then a magnetic flux density calculation method appropriate for S-FEM to calculate nonlinear electromagnetic fields is introduced. In the calculation of motor magnetic field, ES-FEM has a proper softening effect on the stiffness matrix of the finite elements, which makes the calculation more accurate and more efficient than FEM. The magnetic flux intensity calculation method introduced in this paper is not only appropriate for ES-FEM to calculate the nonlinear electromagnetic field of motor, but also can improve the calculation accuracy of magnetic flux density. In the calculation of nonlinear magnetic field of motor, ES-FEM can also improve the calculation accuracy of magnetic field analysis compared with FEM. Several numerical examples demonstrate the improving effect of the ES-FEM discussed above on the motor's magnetic field calculation.

A Multibranch Deep Neural Network for the Superresolution of Solar Magnetograms

The existing superresolution (SR) models for solar magnetograms are mostly borrowed from the SR models for natural images. They are less effective for processing solar magnetograms with a very large dynamic range and very rich image features. In this paper, a multibranch superresolution (MBSR) model is specially designed for solar magnetograms. First, we split a low-resolution magnetogram into a group of overlapping image patches, and classify them into three categories according to magnetic flux intensity, namely simple, medium, and complex. Then, image patches of each category are fed into the corresponding branch of the MBSR network, the lightweight branch for simple image patches and the heavyweight one for complex image patches. The advantage of such a strategy is twofold. On the one hand, active regions are allocated more computational resources to train a heavyweight branch more fully, while quiet regions are allocated fewer computational resources to train a lightweight branch for saving computational resources. On the other hand, a lightweight network with a simple nonlinear function is preferable to simple regions, while a heavyweight one may be underfitting. Additionally, to verify the effectiveness of the proposed model, a magnetic field structure similarity metric is proposed to measure the artifacts of the generated high-resolution (HR) magnetograms. Experimental results show that the proposed MBSR model generates HR magnetograms highly consistent with the HMI ones, and achieves the best performance over five objective metrics, including peak signal-to-noise ratio and structure similarity, etc.

A novel hybrid magnetic material based on three-phase saturated core fault current limiter

Installing a three-phase saturated core fault current limiter (TSFCL) is an effective method to limit the increasing short-circuit current in high-voltage alternating current (HVAC) systems. However, the traditional TSFCL uses silicon steels as its working material for the iron core, resulting in poor current-limiting effects, requiring a large DC excitation current, and having a slow response speed. Nanocrystalline alloys have advantages such as a lower saturation point, higher permeability in the unsaturated zone, and a steep B–H curve, making them highly suitable for TSFCL’s applications. However, their poor capability which withstands fault hindered their large-scale commercialization. Therefore, this paper proposes a novel hybrid magnetic material based on TSFCL (HMTFCL), where the materials of the working limbs are replaced by nanocrystalline alloys. Compared to TSFCL, the DC excitation current of HMTFCL decreases by 60.5%. And, the HMTFCL reduces the peak short-circuit current by 23%. Last, the magnetic flux intensity inside the working limb of HMTFCL is reduced to zero more quickly.

The Magnetic Field Freezes the Mercedes-Benz Water Model.

In this study, we investigate the impact of magnetic fields on the structural and thermodynamic properties of water. To accomplish this, we employed the Mercedes-Benz (MB) model, a two-dimensional representation of water using Lennard-Jones disks with angle-dependent interactions that closely mimic hydrogen bond formation. We extended the MB model by introducing two charges to enable interaction with the magnetic field. Employing molecular dynamics simulations, we thoroughly explored the thermodynamic properties concerning various magnetic flux intensities. As a result, we observed that under a weak magnetic flux, the property of water remained unaltered, while a stronger flux astonishingly led to the freezing of water molecules. Furthermore, our study revealed that once a specific flux magnitude was reached, the density anomaly disappeared, and an increase in flux caused the MB particles to form a glassy state.

Performance Analysis of Conventional IPMSM and NCPM Based IPMSM

This paper proposes a NCPM (Nano-composite coated permanent magnets)-based IPMSM (Interior Permanent Magnet Synchronous Motor) electric drive system, especially applicable for electric vehicles (EV). For an EV, an increase in the “T/A (torque per ampere)” condition is highly recommended, as it directly affects the maximum distance run by EV on a single charge. Due to NCPM, a substantial increase in magnetic flux intensity, resistance to corrosion and Curie temperature are observed. As a result, the proposed drive clearly exhibits a higher power to weight ratio. Also, it is capable of delivering higher T/A to the drive system without any considerable change in two important factors of EV: (1) mass and volume of the drive system (2) battery capacity of the drive system. Moreover, NCPM performance is less susceptible to temperature variation, which makes it an appropriate candidate for vehicular applications, where temperature inconsistency could be a common issue during working conditions. Also, NCPM-based IPMSM offers a quicker speed response than conventional IPMSM, thus providing higher acceleration, which is one of the important performance factors for vehicular applications. A vector controlled mathematical model of IPMSM and NCPM-based IPMSM is tested for various speed commands. Also, the NCPM-based IPMSM, in the proposed configuration, is fed from a three-level DCMLI (diode clamped multi-level inverter), as the drive system is considered for medium to high power applications. A comparative performance analysis is carried out between the proposed drive system and a conventional IPMSM-based drive system using MATLAB/SIMULINK to indicate the efficacy of the proposed configuration.

Numerical simulation of coupling behavior in coaxial hybrid arc welding apparatus

Double-layer coaxial hybrid arcing technology has been developed based on an inner constraint arc and an outer ring arc; the heat and pressure properties of the arc source are supposed to be decoupled and leading to improved controllability of the weld pool thermal-force state. But, the coupling state between the two arcs is not uncovered, and the process window for stable hybrid arc is narrow. In this study, a numerical model of the coaxial hybrid arc system is established, the influence of the water-cooled nozzle on the arc is considered, and the model's accuracy is verified by the measured arc pressure. The physical fields, such as temperature, velocity, and current density distribution, of the hybrid arc are calculated, and the influence of the inner constraint arc current or outer ring arc current on arc pressure and the coupling state in the hybrid arc are uncovered. It was found that (1) at the center of the stable hybrid arc, the current density, magnetic flux intensity, Lorentz force, and arc pressure with a rise in constraint arc current are higher than with a rise in outer arc current; (2) given the total current, adjust the proportion of the inner or outer arc currents, the total heat input basically remains unchanged; and (3) the cause of the arc collapse phenomenon, which is challenging to explain experimentally: the non-ionized gas layer in the orifice throat is broken through.

Effect of Pole Head Profile on Torque Performance of a Disc-Type Multipole Magnetorheological Brake

A magnetorheological brake (MRB) works on the shearing effect of MR fluid in the magnetic field to develop resistance between the stator and the rotor, which are relative moving surfaces. Researchers achieved high torque volume ratios in magnetorheological fluid braking systems by adding multiple layers and using multipole approaches. Even though several designs already exist, there is a need for innovative ideas and advanced structures of MRBs for practical engineering applications. The number of magnetic poles, pole geometry and placement have a significant effect on the performance of multipole MR brakes. This research focused on the effect of the pole head geometry in a multipole dual disc compact MR brake to understand the relationship between the geometry and its magnetic flux flow. The magnetic field generated by the electromagnetic coil’s orthogonal travel through pole heads, rotor and MR fluid layers results in friction to fulfill the action of braking that achieves maximum brake torque. This flow depends on the magnetic pole head area and corresponding core dimensions. This study considered polygon, square, hexagon, trapezoid and ellipse pole head profiles in place of the conventional circular pole and the best possible core dimensions were used for each geometry. To study the brake’s performance, COMSOL Multiphysics software (version 5.5) commonly used for 3D electromagnetic modeling was used to simulate and examine the magnetic flux intensity for various pole head configurations. Results indicate an improvement compared to previous works, considering the same dimensional limitations and the flux leakage between the adjacent poles being much less. The hexagonal and elliptical pole heads had better magnetic field area, magnetic intensity distribution and higher magnetic flux lines piercing through the MR fluid perpendicularly than the circular and square pole heads. An increment of 3.88% for braking torque performance was obtained, and the braking torque was significantly enhanced.

Boosting the energy harvesting performance of cantilever structured magneto-mechano-electric generator by controlling magnetic flux intensity on magnet proof mass

A cantilever-structured magneto-mechano-electric (MME) generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks. Recently, the concept of a magnetic flux concentrator (MFC) to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced. However, the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam. Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator, optimizing the volume and position of the proof-mass with MFC is crucial for better performance. Furthermore, a smaller proof-mass is desirable for the long-term reliability of cantilever-type harvesters. Hence, we investigated the effect of the position and weight (volume) of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments. The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field, which was 210% of that of the MME configuration used in our previous study. Furthermore, the MME generator showed broadband characteristics around the practical frequency of 60 Hz, which could provide more freedom to design the harvester with high performance.

Characteristics of electromagnetic vector field generated from rock fracturing

Rock fracturing is often accompanied by electromagnetic phenomenon. As a vector field, in addition to the intensity that is widely concerned, the generated electromagnetic field also has obvious directionality. To this end, a set of electromagnetic antennas capable of simultaneous three-axis measurement is used to monitor the electromagnetic vector field generated from rock fracturing based on Brazilian tests. The signal amplitude on each axis can represent the magnitude of actual magnetic flux density component on the three axes. The intensity and directional characteristics of electromagnetic signals received at different positions are studied using vector synthesis. The directionality of electromagnetic radiation measured using a three-axis electromagnetic antenna shows that the direction of the magnetic flux intensity generated by rock fracturing tends to be parallel to the crack surface, and the measured signal intensity is greater in a direction closer to the crack surface.

An Independent Dual-Coil Driving Topology for Wireless Power Transfer

The existing dual-coil driving topology mostly adopts two inverters or additional switching circuit, which increases the cost and size, and the complexity of the wireless power transfer (WPT) system. In this letter, a novel inverter topology with independent dual-coil driving capability is proposed for WPT applications, where the main switch and auxiliary switch can drive two independent coils. Moreover, this topology not only offers wide zero voltage switching range and compact size, but also improves the output power and coil utilization. Meanwhile, a quadruple D square (QDS) coil with uniform magnetic field is discussed with the dual-coil driving topology. The detailed parameters design of the proposed topology is discussed and the QDS coil is compared with other coils in terms of magnetic flux intensity. Finally, a 1MHz and 220W wireless power transfer system is built to verify the proposed topology and coil structure.

Computational Numerical Analysis of a Magnetic Flux Permanent Magnet with Different Shape for The Development of a Hybrid Generator

A hybrid generator is one of the attempts to reduce carbon emissions in electricity generation, as it could replace the combustion system currently used in generator sets to generate electricity while increasing carbon emissions. In the hybrid generator system, Lenz's rule of electromagnetic induction is applied in reverse by using a relay to change the polarity of the solenoid coil's electric current. The permanent magnet in the solenoid coil generates mechanical energy (motion) and thereby moves the generator engine, since the permanent magnet is connected to the generator engine via the crankshaft. The objective of this study is to determine and compare the behaviour of N55, N52, N42, N42SH, and samarium-cobalt permanent magnets for the magnet system. The objective of this study is also to find a suitable permanent magnet for use in the magnet system to increase the power generation efficiency. A simple model is simulated to achieve the desired result, including magnetic flux density inside and around the magnets, magnetic field strength calculation, and applied force. The simulations and analysis are performed using ANSYS R19 software and finally all the data are recorded and compared to select the best magnet and develop a prototype. The permanent magnet inside the solenoid plays an important role in the hybrid generator and it is crucial to choose the suitable permanent magnet to increase the efficiency of power generation. From the data, Alliance N-55 permanent magnet has the highestmagnetic force of 131.57 N for 1 mm because it has significantly higher magnetic flux density, magnetic flux intensity and magnetic force.

Elementary Research on Magnetic Field Sensing Capability of Spiral Conductive Polymer Composite

To realize the magnetic field measurement based on the intrinsic flexible/stretchable sensor, the conductive polymer composite is fabricated into a spiral structure. The change in the magnetic field can generate the induced electromotive force of the spiral composite. The experimental data show that the effective value for the induced electromotive force of the spiral composite increases with the increase of the the effective value for the magnetic flux intensity, and the sensitivity is 6.32 mV/μT. Both the induced electromotive force and the electrical resistance change with the deformation of the spiral composite, whereas the change in the magnetic field cannot lead to the variation of the electrical resistance of the spiral composite. Based on the aforementioned changing rules of the resistance and the induced electromotive force, a method to eliminate the interfering effect of the deformation on the magnetic field measurement based on the spiral composite is designed preliminarily. The aforementioned results have proved elementarily the feasibility of using the spiral composite to measure the magnetic field.

Embedding hidden information in additively manufactured metals via magnetic property grading for traceability

Use of counterfeit goods has a large negative impact on manufacturing industry. Recently, counterfeiting of additively manufactured parts is being facilitated by advances in 3D scanning methods, which enable users to retrieve high resolution models and improve reverse engineering approaches. The present study develops and validates a methodology for encoding part authentication information within additively manufactured hardware during part fabrication which is based on embedding a ferromagnetic physical tag within a non-magnetic product. To demonstrate the applicability of this technique, non-magnetic 316 stainless steel was fabricated via laser direct energy deposition with embedded ferromagnetic 430 or 17-4PH stainless steels regions for local control of the magnetic response. The magnetic flux normal to the surface was recorded using a custom built 3-axis magnetic sensor to obtain magnetic flux intensity maps, revealing the embedded magnetic regions. The distribution of the magnetic regions, also characterized using scanning electron microscopy evaluations, can be retrieved from this map revealing the features of the physical tag. Magnetic response of the composites is explained as a function of local composition changes and crystalline structure. The methodology introduced here can be used to embed several traceability tools such as magnetic barcodes and Quick Response (QR) codes away from the surface, which can be detected on demand, in 3-D printed parts.

Improving Groundwater Quality by Electromagnetic Polarization

The aim of this study is to contribute to easy access to soft water, improve some of their properties, and try to find an inexpensive economic method. The research lies in two parts, the first part included a stage of design calculations for the electromagnetic water treatment device. The stage of designing laboratory experiments according to the Box-Wilson statistical method, after determining the independent approved variables. The second part, laboratory work included two stages, namely, the stages of operating the device and examining it within the specific operational conditions of the experiments, and the other area is conducting the necessary tests on the water sample. Two programs were used SPSS programme and MATLAB programme. The results showed an improvement in the concentration of the total hardness, with a rate ranging from 14% to 35%, magnetic flux intensity ranging from 0.5 to 1.1 Tesla, an exposure time of ranged from 17 to 48.5 seconds, and the equation for these experiments was found. Multiple tests were conducted to find out the concentration of total dissolved solids, which recorded an insignificant decrease from 2% to 4%, and therefore their results were not significant. Research benefits by avoiding the use of economically costly chemicals (Alum) that are dangerous to the environment and humans.

Temperature gradient control of frequency conversion heating for a thick-walled pipe based on energy transfer

Characterized by energy concentration, electromagnetic heating technology has a significant advantage in achieving local rapid heating of a workpiece. However, electromagnetic heating may create a great temperature gradient in the wall thickness direction for a workpiece with a thick wall that requires penetrating heating. To improve the evenness of the temperature between the internal and external surfaces, a frequency conversion heating method is proposed. An electric–magnetic–thermal coupling model for frequency conversion heating of welded pipes is established and verified by temperature measurement experiments, thereby revealing the distribution characteristics of the induced current, temperature, and magnetic flux intensity. On this basis, a new concept—the energy surface—is defined. An induction heating schedule suitable for thick-walled pipes is formulated with the energy surface transfer characteristics. The electromagnetic distribution resembles the topology of an underwater lake. There is a "demagnetization region" with a magnetic flux intensity of < 0.321 T. The field width varies with the frequency. The temperature difference along the wall thickness of the welded pipe reaches its maximum after the critical demagnetization surface manifests. By controlling the frequency conversion heating, the temperature difference can be decreased to 88.82%, thus improving the induction heating quality of the welded pipe. This study provides a measurable theoretical reference basis for investigating the change in the internal heat source caused by the change of electromagnetic characteristics to accurately control the temperature gradient.

Magnet-actuated loading of magnetic conductive high-viscosity droplets

The dispensing resolution of high-viscosity magnetic conductive adhesives is essential for the bonding of magnetic components. Here, a novel magnet-actuated loading method based on transfer printing is proposed. The core of the loading method is the forming and breaking of a cone-shaped liquid bridge. The complete loading process is simulated using a computational fluid dynamic technique. With the homemade device and electromagnetic needle-stamp, the loading process is experimentally investigated. According to the results, magnetic flux intensity, viscous force, and surface tension together dominate the formation of the cone-shaped liquid bridge from an adhesive film. For the formed cone-shaped liquid bridge, its geometry size is dominated by magnetic flux intensity, which is controlled by the variation of the initial distance between the needle-stamp and the adhesive film. As the initial distance decreases, the top area of the liquid bridge on the needle-stamp correspondingly increases and the adhesive effect on the needle-stamp gradually strengthens. After the liquid bridge breaking, the volume of loaded droplets adhering to the needle-stamp gradually increases from about 0.11 to 1.41 nL with the standard deviations less than 0.08. Moreover, these loaded droplets are transferred to the substrate by the microforce feedback, and a transferred droplet with a minimum area of about 0.01 mm2 is obtained. The presented method gets rid of the limitation of submicron needle-stamps, realizes the loading of sub-nL high-viscosity droplets, and has great potential in microdispensing and other related techniques.

Comparison of Magneto-Optical Faraday Effect Method and Magnetic Camera for Imaging the 2-D Static Leakage Magnetic Flux Density

Magnetic flux leaks around the defect on the magnetized ferromagnetic specimen. The magnetic flux leakage testing (MFLT) use the magnetic sensor to measure the leaked magnetic flux density (LMFD). The high sensitivity of sensor need to increase the probability of detection (POD). Also the small size and high spatial resolution of sensor need to increase POD and to sizing defect. Uniform and small lift-off are another necessary to increase POD and sizing ability. Also, the real time imaging of magnetic flux density can increase the inspection time. So the period of planned preventive maintenance could reduce. Two dimensional semiconductor-based magnetic sensor array with high spatial resolution satisfies these requirements. Projection of magnetic flux density on a sensor itself would be another method. We compare the magnetic camera and the magneto-optical Faraday effect (MOE) for MFLT. Magnetic camera uses the two dimensional Hall sensor arrays to imaging the LMFD. And the MOE project LMFD. The plane of polarized light rotates inside of magneto-optical film (MOF). The Faraday rotation angle proportional to direction and intensity of magnetic flux density. Sensitivity, spatial resolution, magnetic hysteresis, repeatability, full-scaled operational range compared. Also shape of target specimen compares too.