Magnetic Repulsive Force Research Articles

Levitating Magnetic Insoles: A Novel Approach to Alleviating Plantar Fasciitis Through the Reduction and Redistribution of Plantar Pressures

Plantar fasciitis, a leading cause of foot pain, affects a significant portion of the population, with an estimated prevalence of 10% during an individual’s lifetime. This debilitating condition can result in substantial healthcare costs and decreased quality of life. The pain is attributed to the inflammation of the plantar fascia, which is crucial for supporting the foot's arch. Risk factors for plantar fasciitis include obesity, sedentary lifestyles, improper footwear, and biomechanical abnormalities. Current treatment options are primarily conservative, with varying levels of success. In response, an affordable, lightweight, and soft, magnetic insole was developed as a novel approach to alleviate plantar fasciitis by reducing and redistributing plantar pressures with neodymium magnets. The final prototype achieves a magnetic repulsion force of approximately 84.57 lbs. and incorporates sensor modules to monitor data. The device also facilitates real-time data visualization between Arduino and personal devices, providing valuable insights into plantar pressure and walking characteristics for various patients. Data analysis and structural optimization are further enhanced through the use of MATLAB and Excel, which generate heatmaps to visualize plantar pressure distribution. Future research should focus on increasing the magnetic intensity to improve pain relief effectiveness and incorporating personalized disease-specific adjustments to optimize the magnet placement within the sole. By addressing the prevalent issue of foot pain and offering a potential solution for plantar fasciitis, our levitating magnetic insoles demonstrate significant potential for enhancing the quality of life for a large portion of the population.

Nonlinear dynamics of magnetically coupled double beam based piezoelectric energy harvester under galloping excitation

This paper presents a magnetically coupled double cantilever beam-based piezoelectric energy harvester. Two square-shaped bluff bodies are attached to the tip of the beams to induce galloping-based oscillation in the proposed system. Spatio-temporal electro-mechanical equations of motion are developed using the Lagrange principle and discretized to their temporal form using generalized Galerkin’s method. 4th order Runge-Kutta method-based MATLAB solver (ode45) is used to solve these equations of motion and obtain numerical results. A prototype of the system is developed and experimented in a wind tunnel to support the numerical findings. Three wind speed regions (light air, light breeze, and gentle breeze) based on the Beaufort wind force scale are considered for getting a detailed insight into the system dynamics. Periodic, quasi-periodic, and chaotic oscillations are observed depending on different coupling conditions and wind speeds. Typical hopf bifurcation, Torus 3 bifurcations occur in the system due to galloping and magnetic repulsive force. Parametric studies are conducted for each wind speed region considering the load resistances and distance between the permanent magnets. Significant improvement in power output can be found for light air and gentle breeze regions with the magnetically coupled system than the uncoupled system (without magnetic interaction), whereas the uncoupled system performs better in the light breeze region.

High-velocity micromorphological observation and simulation of magnetorheological gel using programmable magneto-controlled microfluidics system and micro-tube dynamic models

Application of magnetorheological gel (MRG) is a promising tool for high performance mitigation due to its outstanding energy absorption and dissipation properties. However, the lack of recognition on micromorphological variation for MRG and its magneto-mechanical coupling mechanism limits its extensive application. Herein, combined with the magnetic sensitivity nature of MRG, we develop a magneto-controlled microfluidic system for flexible simulation toward ms-level impact conditions. Microstructural changes of MRG, prepared with solid–liquid composite method, are characterized from variable magnet-field setups and gradual velocities. Experiments reveal that the increasing magnetic flux density can effectively enhance the stability of chains in as-fabricated MRG, while the chains can support excessive velocities up to 4.5 m s−1 before breaking. Meanwhile, under the preset velocity range, the maximum change rates of the average and standard deviation for inclinations are 183.71% and 40.06%, respectively. Successively, an experiment-conducted microdynamic model is developed for numerical simulation of the MRG mechanical behaviors. During that, high-velocity MRG behaviors are explored with a tubular rather than regular flat-structure boundary condition setups, to pursue more trustable results. Simulation readouts meet nicely with those from experiments in revealing the magneto-mechanical coupling mechanism of MRG under multiphysics. The interaction between magnetic force, repulsive force and viscous resistance is mainly illustrated. This work provides a reliable observation basis for micromorphological variation of MRG, also suggests a new method for the mechanism of magneto-mechanical coupling at extreme velocities.

Design of High-Remanence Nd-Fe-B Hot-Pressed Magnets by Manipulating Coercivity of Hydrogenation-Disproportionation-Desorption-Recombination Treated Anisotropic Precursors.

We propose a method of manipulating the coercivity of anisotropic hydrogenation-disproportionation-desorption-recombination (HDDR) powders to fabricate high-remanence and fine-grained Nd-Fe-B magnets using only hot-pressing without a subsequent hot-deformation process. By reducing the Nd content of anisotropic HDDR precursors such that their coercivity (Hcj) is lowered, the c-axis of each HDDR particle is well-aligned parallel to the direction of the applied magnetic field during the magnetic alignment step. This is because the magnetic repulsive force between adjacent particles, determined by their remanent magnetization, decreases as a result of the low coercivity of each particle. Therefore, after hot-pressing the low-Hcj HDDR powders, a significantly higher remanence (11.2 kG) is achieved in the bulk than that achieved by hot-pressing the high-Hcj HDDR powders (8.2 kG). It is clearly confirmed by the large-scale electron backscatter diffraction (EBSD) analysis that the alignment of the c-axis of each anisotropic HDDR particle in the bulk is improved when low-Hcj HDDR powders are used to fabricate hot-pressed magnets. This coercivity manipulation of HDDR powders can be a helpful method to expand the use of HDDR powders in fabricating anisotropic Nd-Fe-B bulk magnets.

Approach towards green manufacturing in Maglev EDM using different biodegradable dielectrics at variable discharge conditions

The urge to implement eco-friendly approach for modern manufacturing techniques has assisted in eliminating the hazardous effect of the undesirable byproducts released into the atmosphere. In electro-discharge machining (EDM) process, the hydrocarbon oil degradation releases various toxic gases and non-biodegradable residuals as byproducts. Several bio-dielectrics have been implemented to overcome such setbacks as an economical replacement to conventional hydrocarbon oil dielectrics. The current research demonstrates a green Maglev EDM operation on Ti-6Al-4V alloy using neem oil and canola oil as bio-dielectrics compared with EDM oil. Maglev EDM utilizes novel bipolar linear self-servo strategy for tool positioning which generates consistent machining stability by unique magnetic repulsive force balance action. The performance characteristics of all the dielectrics have been examined through machining rate (MR), tool wear rate (TWR), consumed specific energy (SE), area roughness parameters and surface morphology. The results were compared for respective bio-dielectric at variable discharge voltages (VD) i.e. 22 V, 25 V and 28 V, whereas the discharge current (ID) varied within (220-250 mA). The performance assessment depicts (25 to 28) % lower SE consumption in neem oil and (35 to 37)% in canola oil as compared to EDM oil. The surface morphology assessment portrays lower deformities and better uniformity using bio-dielectrics with huge potential for selective surface modification.

Effect of the number of magnetic matrices on particle capture in high gradient magnetic separation

A comprehensive understanding of the capture process involving matrices in high gradient magnetic separation (HGMS) is crucial for the design and improvement of matrix performance. However, few existing studies have paid attention to the influence of the number of magnetic matrices on the capture process. In this work, we numerically investigate this issue in both longitudinal and transversal HGMS systems, where multiple scenarios with different particle sizes, flow rates and matrix spacing are considered. Interestingly, we show that in most cases, increasing the number of magnetic matrices along the flow direction has little to no influence on the capture radius. It has a certain effect on improving the capture radius only in a few specific cases, such as when dealing with large particles at low flow rates with closely spaced matrices or when working with small particles at high flow rates with widely spaced matrices. These phenomena are related to the appearance of repulsive magnetic forces around matrices and the distribution characteristics of magnetic forces. The obtained results indicate that, in the design of the practical HGMS system, simply increasing the number of matrices along the flow direction may not be a reasonable or effective strategy for enhancing capture performance.

Viability and performance assessment of bipolar linear self-servo mechanism-based Maglev electrical discharge machining by processing Al-6062 alloy

The enhancement of process efficiency and eradication of basic setbacks of the electrical discharge machining (EDM) process has paved the way for its technological advancement. The discharge irregularities observed during conventional EDM operation due to servo-feedback delay have been addressed by implementing a novel bipolar linear self-servo strategy in Maglev EDM. The paper evaluates the viability of the novel Maglev EDM and analyses its performance in machining aluminum (Al) 6062 alloy. The Maglev EDM uses a systematic combination of magnetic repulsive forces to attain tool positioning in the Z-direction, which serves as the servo gap control mechanism. Experiments were carried out on Al-6062 alloy by utilizing brass tools and surrounding air as dielectric. The voltage–current waveforms exhibited stable and uniform discharges devoid of the short-circuiting and arcing phenomenon. Material removal rate, specific energy, and centerline average surface roughness of 6.717 µg/s, 2.397 J/µg, and 3.735 to 4.507 µm were attained at a discharge power of 16.1 J/s, proving the operational viability of the Maglev EDM. The experimental results were further compared with data available in the previously reported literature. Resolidified layers, globules, lumps of debris, melted debris, micro-pores, micro-voids, micro-cracks, and craters were detected from field emission scanning electron microscopy analysis of the processed work surface. The existence of tool material in the processed surface by energy-dispersive X-ray spectroscopy analysis certified the material migration and surface alloying.

Concise magnetic force model for Halbach-type magnet arrays and its application in permanent magnetic guideway optimization

In maglev trains, a permanent magnetic guideway (PMG) is an indispensable component that influences their levitation stability. PMG generates the magnetic repulsion force in permanent magnetic levitation and provides the pinning force via coupling with bulk superconductors in superconducting magnetic levitation. Typically, they are arranged in a Halbach array to enhance the magnetic force. However, the spatial inhomogeneous feature of magnetic field makes magnetic force acquisition of the double-sided Halbach array extremely difficult. For accurate magnetic force acquisition, this study proposes a concise analytical magnetic force model and elucidates upon its field behavior. Based on this, a finite element method (FEM) model was developed and verified. The experimental results demonstrated that the Halbach-type PMG’s field distribution was effectively reproduced. Subsequently, the accuracy of the was obtained via comparison with the FEM. The calculation results revealed that the increase in the levitation force tends to be saturated as more magnets are used. For a feasible PMG configuration in terms of high levitation force and low lateral force, the structural parameters were optimized using the multi-objective particle swarm optimization (MOSPO) algorithm combined with the identified magnetic force formulas. The results and findings of this study have significant implications for the design optimization of guideway configurations that heavily rely on permanent magnets.

Experimental analysis of nonlinear piezo-electromagnetic composite human energy harvester

To better harvest the kinetic energy of the human and broaden the energy harvest frequency band, a nonlinear piezo-electromagnetic composite human energy harvester (NPE-HEH) is proposed. A magnetic repulsion force between the two groups of magnets makes the energy harvester nonlinear. The excitation experiment and the actual experiment of the human are carried out for the harvester. The excitation experiment results show that there is an optimal resistance value of the harvester to maximize the output power value. When the excitation acceleration is 0.4 g and the excitation frequency is 9 Hz, the output voltage value and the output power of the electromagnetic part of the energy harvester are 0.86 V and 2.47 mW respectively, and the output performance is excellent. When the energy harvester is installed in a backpack with a moving speed of 9 km/h, it can generate 0.7 mW of power. When the energy harvester is placed on the leg, the output performance is good and the output power can reach 1.3 mW. The energy harvester can efficiently harvest energy at low frequencies. This harvester is efficient at low frequencies, compact in size, and easy to carry, making it highly suitable for human vibration energy harvesting applications.

Development of Bi-2223 Model Magnet for Magnetic Refrigeration System

We have started the development of a magnetic refrigeration system for hydrogen liquefaction. This system comprises a superconducting magnet, wherein an active magnetic regenerative (AMR) bed moves through. To investigate its applicability to the magnetic refrigeration system, a Bi-2223 superconducting magnet with compensation coils at both ends was designed and fabricated. The magnet was designed to generate 4.76 T at a rated current of 300 A. Compensation coils at both ends reduce the magnetic field outside the bore to zero. The magnet was fabricated as a stack of epoxy-impregnated double-pancake coils. The cooldown period of the magnet was approximately 82 hours. However, the quench detector ceased the power supply at 229 A (3.63 T), due to voltage oscillations in the coils, likely arising from compression due to the magnetic repulsive force.

Measuring lateral capillary forces on floating particles using the Moses effect.

This study presents a novel and user-friendly technique for detecting the lateral capillary force on a floating spherical particle. The technique leverages the interplay between the capillary attracting forces, hydrostatic pressure forces, and magnetic repulsion forces. A magnetic field is applied to induce a surface curvature in the liquid, resulting in a non-uniform distribution of capillary and hydrostatic pressure forces across the particle's surface. This leads to a stable equilibrium position of the particle at a specific distance from the magnet. The study analyzes the equilibrium position and other relevant parameters in comparison with the developed theory. Classical mechanics and intermolecular forces are applied to establish the theoretical basis for the method, modeling the behavior of the particle in response to the magnetic field, surface curvature, and hydrostatic pressure. The equilibrium position of the particle is determined by numerically solving the balance of forces equation.

Magnetic Bistability for a Wider Bandwidth in Vibro-Impact Triboelectric Energy Harvesters.

Mechanical energy from vibrations is widespread in the ambient environment. It may be harvested efficiently using triboelectric generators. Nevertheless, a harvester's effectiveness is restricted because of the limited bandwidth. To this end, this paper presents a comprehensive theoretical and experimental investigation of a variable frequency energy harvester, which integrates a vibro-impact triboelectric-based harvester and magnetic nonlinearity to increase the operation bandwidth and improve the efficiency of conventional triboelectric harvesters. A cantilever beam with a tip magnet was aligned with another fixed magnet at the same polarity to induce a nonlinear magnetic repulsive force. A triboelectric harvester was integrated into the system by utilizing the lower surface of the tip magnet to serve as the top electrode of the harvester, while the bottom electrode with an attached polydimethylsiloxane insulator was placed underneath. Numerical simulations were performed to examine the impact of the potential wells formed by the magnets. The structure's static and dynamic behaviors at varying excitation levels, separation distance, and surface charge density are all discussed. In order to develop a variable frequency system with a wide bandwidth, the system's natural frequency varies by changing the distance between the two magnets to reduce or magnify the magnetic force to achieve monostable or bistable oscillations. When the system is excited by vibrations, the beams vibrate, which causes an impact between the triboelectric layers. An alternating electrical signal is generated from a periodic contact-separation motion between the harvester's electrodes. Our theoretical findings were experimentally validated. The findings of this study have the potential to pave the way for the development of an effective energy harvester that is capable of scavenging energy from ambient vibrations across a broad range of excitation frequencies. The frequency bandwidth was found to increase by 120% at threshold distance compared to the conventional energy harvester. Nonlinear impact-driven triboelectric energy harvesters can effectively broaden the operational frequency bandwidth and enhance the harvested energy.

VIBRATION ISOLATION SCHEME BASED ON ELECTROMAGNETIC SPRING

Sensitive measurements require a vibration isolation system to safeguard against detrimental tremble. Two types of vibration isolation systems - passive and active - are currently implemented. The spring-based passive designs usually accompany with ineffective low-frequency response. Therefore, the active designs, consisting of sensors, feedback control systems, and actuators, are consolidated to improve the total effectiveness of the cancellation performance. In this work, we focus on developing the actuator founded on electromagnetic spring to be incorporated into our compact quantum gravimeter. Each spring-actuated part comprises two repelling Nd magnets positioned face to face inside a solenoid. With this configuration, the spring can also work in the passive mode via repulsive magnetic force. In the active mode, the exerted force is a result of magnetic fields formed by the magnets and the current-controlled solenoid coils. By changing the coil current, the stiffness of the spring can be modified, and thus the displacement can be controlled. Different sizes of magnets are explored, and their force behaviors in passive and active modes are characterized. The implementation scheme of the actuator in the quantum gravimeter is also discussed.

Enhanced airfoil-based flutter piezoelectric energy harvester via coupling magnetic force

This paper proposes a novel magnetic coupled airfoil-based flutter piezoelectric energy harvester, for decreasing the critical velocity, broadening the working bandwidth, and achieving more efficient harvesting performance at lower airflow velocity. The conceptual designing of the harvester system via coupling magnetic force is first conducted, the mathematical and simulation models of the fluid–structure-electric–magnetic coupled fields are then established, and the experimental prototypes are finally fabricated. The influences of the structural parameters of the harvester system on the vibration response and output performance are fully studied. The results show that the magnetic repulsion force decreases the equivalent stiffness of the harvester system and makes it easy to couple plunge-pitch motions. A decrease in the magnet spacing distances leads to decreasing the critical velocity and improving the output performance. Compared with the magnetic spacing distance of 25 mm, the critical velocity with the magnetic spacing distance of 17 mm decreases by 70%, and the enhancement ratio of output power increases by 50% at 13.8 m/s. The flow field demonstrates that the alternating pressure difference drives the harvester system to take place two DOF plunge-pitch motions. The experimental results are in good agreement with the theoretical values, which verified the established mathematical model. The designed magnetic coupled airfoil-based flutter harvester system achieves a larger vibration response and better harvesting performance at lower airflow velocity. This work provides essential foundations for achieving better harvesting performance via coupling magnetic force.

A tunable rotational energy harvester exploiting a flexible-clamping piezoelectric beam by deploying magnetic repulsive force

A tunable rotational energy harvester exploiting a flexible-clamping piezoelectric beam by deploying magnetic repulsive force

A multi-stable ultra-low frequency energy harvester using a nonlinear pendulum and piezoelectric transduction for self-powered sensing

This paper presents the design, theoretical modelling and experimental validation of a quad-stable energy harvester for harnessing ultra-low frequency random motions using a nonlinear pendulum and piezoelectric transduction. The multi-stable pendulum is created by the magnetic forces between magnets on the pendulum and a tip magnet on a piezoelectric cantilever beam. Two attractive and one repulsive magnetic forces in combination with the gravitational force of the pendulum create multiple stable positions for the pendulum. The multi-stable dynamics allow the pendulum to effectively convert low-frequency random kinetic motions from the host, e.g. human motion or wind turbine tower oscillation into the pendulum oscillation, enabling effective plucking of the piezoelectric beam with enhanced output power. A theoretical model, including the magnetic interaction, piezoelectric conversion and pendulum dynamics, is established to describe the electromechanical dynamics of the whole harvester. A prototype is fabricated and tested on a linear shaker at ultra-low frequencies (1–3 Hz) to showcase the capability of the harvester and to validate the theoretical results. Around 8 μW Root-Mean-Square output power was obtained at 2.5 Hz and 0.8 g of excitation. Using the experimentally validated theoretical model, a parametric study was carried out to examine the influence of different structural and operating parameters, such as pendulum mass and length, magnetic coupling strength, excitation frequency and amplitude, on the output power and operating frequency range of the energy harvester. The operation frequency range and output power can be effectively adjusted by changing the above-mentioned parameters. The self-powered sensing capability is then illustrated by integrating the harvester with an off-the-shelf power management circuit and a 22 μF storage capacitor. The capacitor was charged from 2.8 V to 4 V in 90 s, showing its capability of implementing battery-free wireless sensing for different Internet of Things (IoT) applications.

Improving energy harvesting by nonlinear dual-beam energy harvester with an annular potential energy function

In this paper, we develop a nonlinear dual-beam energy harvester for broadband energy harvesting. Two identical piezoelectric cantilevers are placed orthogonal to each other and coupled by repulsive magnetic force. Analytical and experimental studies indicate that the combination of the resonant motions of the two beams yields an annular potential energy function, where the oscillator can circumambulate around the potential barrier. The advantages of the design concerning a conventional bistable piezoelectric cantilever were examined. It is proved that the proposed harvester has a bandwidth of 3.4 Hz and a voltage output performance 298.7% better than that of a bistable one under excitations of 0.5 g.

Significantly Improved Separation Efficiency of Refractory Weakly Magnetic Minerals by Pulsating High-Gradient Magnetic Separation Coupling with Magnetic Fluid

High-gradient magnetic separation (HGMS) is indispensably applied in the rougher separation stage of refractory weakly magnetic minerals. The most difficult problem while processing refractory weakly magnetic minerals is the low selectivity of HGMS caused by the competing capture of magnetic valuable and gangue minerals. In this study, a paramagnetic fluid is introduced into HGMS and an innovative method, termed high-gradient magnetic separation coupling with magnetic fluid (HGMSCMF), with a significantly high selectivity is proposed. A new competing force (magnetic repulsive force) generated by the magnetic fluid will enlarge the force difference of valuable and gangue minerals and improve selectivity. The relative magnetic force acting on the magnetic valuable and gangue minerals can be adjusted by varying the fluid volume susceptibility, with the optimal fluid susceptibility approaching that of gangue minerals. HGMSCMF experiments on an ilmenite ore using paramagnetic MnCl2 solutions showed that the selectivity was remarkably improved by increasing MnCl2 concentrations (fluid susceptibility). The TiO2 grade and mass of magnetic products could be simultaneously improved by increasing the applied induction in HGMSCMF, whereas in conventional HGMS, the TiO2 grade and recovery decreased and increased, respectively. HGMSCMF is applicable to various matrices (or separators), and a significantly improved TiO2 grade (close to that of industrial concentrates) could be obtained with only one-stage HGMSCMF. The recycling of magnetic fluid and cost economy of HGMSCMF are also discussed and analyzed. HGMSCMF presents several advantages over conventional HGMS and has great application prospects for realizing the clean and efficient utilization of refractory weakly magnetic minerals or materials.

The Intrinsic Nature of Strong Force to Bind Proton(s) and Neutron(s) to Form Nucleus and the Exploration of Nuclear Reaction

A new nucleus configuration was developed, based on proton or neutron as electric monopole pairs in a thin plate deducted from “the theory of spin vector in motion” developed by us recently. According to the proton and neutron’s configuration proposed, we concluded that the protons and neutrons are bound simply by magnetic force. The protons or neutrons can be bound together in a mode, shoulder-to-shoulder or side by side. The nucleus will be treated as a vertical oval ball with neutrons as the spin axis, with protons filled on different intersection layers with minimum balanced repulsive electric force and repulsive magnetic forces. The radioactivity of isotopic nucleus shall result directly from the unbalanced magnetic force between neutron axis and protons induced by more or less neutron(s) compared to stable isotope. Based on inner structures, spin properties of proton and neutron, we also concluded that there is no “strong force” required to bind quarks or to bind proton(s) and neutron(s) to form a stable nucleus.

Experiment regarding magnetic fields with gravity

This experiment was designed to test the string theory as a physical reality. The ground-based device placed the N poles of the magnets upwards, north, south, east, and west. Coil Ass'Y was placed between 2 N poles with bearing covers on the top and bottom. Gravity interacts to generate electricity in the Earth's direction or the opposite direction by the repulsive magnetic force. The voltage was measured from 3.60 to 3.80 sequentially while the generator was stationary through the monitor. The author found symmetry in Lex Tertia voltage and current zero data during experiment F4 6380 at a balanced state under gravity with the repulsive magnetic force. It generated from 42.8 to 794 μV in the vacuum chamber but from negative 16.1 to positive 18.3 μV in the air. As a result, the author measured more negative current and positive voltage generated in a vacuum. Trapped gravity was set to behave as free relativistic quantum particles or fluids in the magnetic sea. The result made it accessible to study the magnetic sea for different initial superpositions of positive- and negative-gravity spinor states. This might explain the relativistic quantum gravity exists as a physical reality, graviton interacting with photons to induce a magnetic field.