Use Of Permanent Magnets Research Articles

Global environmental cost of using rare earth elements in green energy technologies

Decarbonization of economy is intended to reduce the consumption of non-renewable energy sources and emissions from them. One of the major components of decarbonization are “green energy” technologies, e.g. wind turbines and electric vehicles. However, they themselves create new sustainability challenges, e.g. use of green energy contributes to the reduction of consumption of fossil fuels, on one hand, but at the same time it increases demand for permanent magnets containing considerable amounts of rare earth elements (REEs). This article provides the first global analysis of environmental impact of using rare earth elements in green energy technologies. The analysis was performed applying system dynamics modelling methodology integrated with life cycle assessment and geometallurgical approach. We provide evidence that an increase by 1% of green energy production causes a depletion of REEs reserves by 0.18% and increases GHG emissions in the exploitation phase by 0.90%. Our results demonstrate that between 2010 and 2020, the use of permanent magnets has resulted cumulatively in 32 billion tonnes CO2-equivalent of GHG emissions globally. It shows that new approaches to decarbonization are still needed, in order to ensure sustainability of the process. The finding highlights a need to design and implement various measures intended to increase REEs reuse, recycling (currently below 1%), limit their dematerialization, increase substitution and develop new elimination technologies. Such measures would support the development of appropriate strategies for decarbonization and environmentally sustainable development of green energy technologies.

Technoeconomic Analysis of Rare-Earth Metal Recycling Using Efficient Metal Distillation

Recycling has been proposed as a promising potential source of supply to meet some of the US rare-earth demand for use in permanent magnets. The high growth rates of products that make use of rare-earth magnets, particularly wind turbines and electric and hybrid vehicles, show that their stock in use is on the rise and in the near term will become available as scrap feed for recycling. This study presents an overview of magnet recycling technologies and focuses on the technoeconomic analysis of liquid metal leaching and distillation, including the effect of a new continuous gravity-driven multiple effect thermal system (G-METS) metal distillation technology on energy use and overall cost. The G-METS system can potentially reduce the energy consumption of the overall process to 64 kWh/kg, which is about 30% less than metal production from ore and 61–67% less than the process using conventional distillation.

Voltage Generation in Piezoelectric Energy Harvesting with Magnet: FEA Simulation and Experimental Analysis

Energy harvesting devices are needed as an alternative to batteries as it is costly to power up wireless sensor network. However, the power generated and operating bandwidth for the typical energy harvester are still compromised. Therefore, in this work, the use of permanent magnet in Piezoelectric Energy Harvester (PEH) is proposed to increase the operating bandwidth. A simulation study was conducted using COMSOL Multiphysics software to observe the effect of mechanical tuning using magnet on the voltage produced. It shows that PEH with oscillating magnetic field is capable of reaching generated peak power of 0.775 mW and increase the operating bandwidth by 10%. Experimental setup was also fabricated to further validate the observation at different polarities and varying distances with permanent magnets. It is observed that while the peak power achieved in the attractive mode is smaller as compared to its counterpart, however, its bandwidth is larger.

Modeling the Heating of Rotating Disks in an Electromagnetic Field with the Use of Permanent Magnets

Modeling the Heating of Rotating Disks in an Electromagnetic Field with the Use of Permanent Magnets

Characterization in Dynamic Load Environment of COTS Synthetic Sapphire Bearings for Application in Magnetic Suspension in Space

The present research investigates the application of a cardan suspension making use of permanent magnet (PM) bearings employed to obtain high reliable/low-cost solutions for the permanent alignment of directional payloads such as laser reflectors for the Next Generation Lunar Retroreflector (NGLR) experiment or antennas to be deployed on the moon’s surface. According to Earnshaw’s Theorem, it is not possible to fully stabilize an object using only a stationary magnetic field. It is also necessary to provide axial control of the shaft since the PM bearings support the radial load but, they produce an unstable axial force when losing alignment between the stator and rotor magnets stack. In this work, the use of commercial off-the-shelf (COTS) sapphire as axial bearings in the cardan suspension has been investigated by testing their behavior in response to some of the dynamic loads experienced during the qualification tests for space missions. The work is innovative in the sense that COTS sapphire assembly has never been investigated for space mission qualification. As Artemis mission loads have not been yet provided for NGLR, test loads for this study are those used for the proto-qualification of the INFN INRRI payload for the ESA ExoMars EDM mission. Tests showed that, along the x and y directions, no damages were produced on the sapphire, while, unfortunately, on the z direction both sapphires were badly damaged at nominal loads.

Influence of fully submerged permanent magnets in the evaluation of heat transfer and performance analysis of single slope glass solar still

In this experimental study, permanent magnets with three different sizes (M-1: 32 mm inner diameter, 70 mm outer diameter and 15 mm thick, M-2: 25 mm inner diameter, 60 mm outer diameter and 10 mm thick, M-3: 22 mm inner diameter, 45 mm outer diameter and 9 mm thick) are fully submerged in the single-slope glass solar still. The performance of magnetic solar stills (MSS) with three different sizes at 2 cm depth water to ensure that magnets are fully submerged is compared with conventional solar still (CSS) at the location 17.3850°N, 78.4867°E. Tiwari model is adapted to calculate the heat transfer coefficients (HTC), internal and exergy efficiencies. MSS with M-1, M-2 and M-3 significantly enhanced the convective, radiative, and evaporative heat transfer rate for the 2 cm depth of water. This is due to the desired magnetic treatment of water, which reduces the surface tension and increases the hydrogen bonds. The MSS's total internal HTC, instantaneous efficiencies led CSS by 25.52%, 28.8%, respectively, with M-1. Having various magnetic fields due to different magnets sizes increases MSS's exergetic efficiency by 33.61% with M-1, 33.76% with M-2, and 42.25% with M-3. Cumulative yield output for MSS with M-1, M-2, and M-3 is 21.66%, 17.64%, 15.78% higher than CSS. The use of permanent magnets of different sizes in the MSS is a viable, economical and straight forward technique to enhance productivity.

Structural and magnetic properties of SmCo5−XNiX intermetallic compounds

Modern technological applications in an extensive variety of fields require the use of Permanent Magnets (PMs). Intermetallic compounds such as SmCo5 are already used as high-performance PMs. Reducing the high content of the expensive cobalt in SmCo5 from low-priced transition metals can lead in a cost reduction. This study examines by computational methods the effect of substituting cobalt atoms in the crystal structure of SmCo5 by nickel atoms. The aim is to specify the structure that will be stable and at the same time will maintain high values of magnetization. A series of atomistic simulations are implemented based on Density Functional Theory calculations. Various simulations are performed by considering all possible crystallographic positions of Co and Ni atoms in a SmCo5−xNix compound. Based on energy minimization and maximizing the magnetization we pinpointed the interesting cases. An experimental implementation based on the sample with x = 1 is presented to translate the findings from atomistic simulations to realizable bulk materials. Interestingly, it is concluded that in many cases an energetically favourable atomistic configuration does not exhibit maximum magnetization. It should be noted that for the experimentally investigated case of SmCo4Ni, both the energetically favourable as well as the magnetically maximum configuration have been identified.

Increasing Mobile Robot Efficiency and Versatility Through Manipulation-Driven Adaptation1

Abstract Terrestrial mobile robotics are crucial to a range of missions including planetary exploration, search and rescue, logistics, and national security. Many of these missions require the robot to operate on a broad variety of terrain. Wheels are ideal for energy efficiency but can suffer catastrophic failure when presented with obstacles or complex ground. Legs can help traverse obstacles but at the cost of energy efficiency. Physical adaptation can enable a robot to benefit from both modes of locomotion. This article describes a new approach to physical adaptation through manipulation. Specifically, this article examines how manipulators can be used to change the vehicle’s mode of locomotion and improve energy efficiency and versatility. This article presents “swappable propulsors,” which can be easily attached/detached to adapt the vehicle through the use of permanent magnets. A new robot system that uses its manipulator to discretely switch between wheeled and legged locomotion is created. The experimental results demonstrate how this approach provides a unique combination of energy efficiency and versatility. This study describes the design of swappable propulsors, analyzes how to manipulate them, and describes how they can be used to improve performance. This study extends on prior work with additional analysis, an improved robot prototype, and new experimental results.

Industrially Purified Nd Materials Identified by Distinct Mass-Dependent Isotopic Composition

Rare earth elements (REEs) are considered emerging anthropogenic pollutants. Anthropogenic lanthanum, cerium, samarium, and gadolinium alone, or excess of all the REEs have already been reported in the environment. In addition, it is only a matter of time for neodymium (Nd) of anthropogenic origin to be reported disseminated in the environment, given its growing demand for new technologies and its use in permanent magnets of wind turbine. So far, only in a few cases was the addition of anthropogenic Nd detected in soils and sediments by the measurements of REE concentrations. For this reason, we propose to use the Nd isotopic composition to help the distinction of pollution. The isotopic tracing of Nd using variations in the abundance of 143Nd from the radioactive decay of 147Sm (Nd-radiogenic composition) is one option. Here, we expand the Nd isotopic fingerprinting by the investigation of the stable Nd isotopic composition expressed as δxNd, the relative permil (%0) deviation from the isotopic composition of the pure Nd JNdi-1 reference standard. The measurement of δxNd used a MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) with sample-standard bracketing technique, allowing the determination of precise and accurate Nd isotopic variations. Our results show that Nd-magnets (Neo) and man-made purified Nd materials are not significantly different on average (respectively, δ148Nd of −0.105 ± 0.023 and −0.120 ± 0.141%0). More importantly, they are different from terrestrial rocks (δ148Nd of −0.051 ± 0.031%0). Moreover, the Nd-radiogenic composition of Neo can be highly variable, even when they come from a single supplier. In addition, the study of all Nd stable isotopic compositions demonstrates that irrespective of their natural origin (witnessed by their Nd-radiogenic composition), all Nd from rocks and man-made materials are related by mass-dependent isotopic fractionation laws. We also have defined a parameter, the Δ148−150Nd′, allowing the distinction of thermodynamic isotopic fractionation (the Δ148−150Nd′ is invariant) from kinetic isotopic fractionation (the Δ148−150Nd′ is negatively correlated with the δ148Nd). Such covariation is observed for anthropogenic materials that could be seen as small deficit in 150Nd (around 5 ppm/%0/amu), but too small to be consistent with nuclear field effect. On the other hand, the anthropogenic material defines a covariation in the Δ148−150Nd'–δ148Nd space in full agreement with the theoretical expectation from mass-dependent kinetic isotopic fractionation. The mass-dependent fractionation of Nd by chromatographic separation is also consistent with a kinetic isotopic fractionation. The purification of Nd from other light REEs by industrial processes involves chromatographic separation and, therefore, is likely to produce anthropogenic Nd with low values for δ148Nd associated with high values for Δ148−150Nd′. Both are resolvable with current MC-ICPMS technology and could be useful to trace incoming anthropogenic pollution in the environment. In soils, the combination of low values for δ148Nd with high values for Δ148−150Nd′ is likely to be an unambiguous pollution signal from the degradation in the environment of Neo or other industrial products, especially if this is associated with an Nd-radiogenic composition inconsistent with the surrounding rocks and soils. In contrast, the industrial residue of Nd purification could be characterized by high δ148Nd with low values for Δ148−150Nd′, and the leak or the discharge of such residue could also be unambiguously distinguished.

Contactless Nanoparticle-Based Guiding of Cells by Controllable Magnetic Fields.

Controlled and contactless movements of magnetic nanoparticles are crucial for fundamental biotechnological and clinical research (eg, cell manipulation and sorting, hyperthermia, and magnetic drug targeting). However, the key technological question, how to generate suitable magnetic fields on various length scales (µm–m), is still unsolved. Here, we present a system of permanent magnets which allows for steering of iron oxide nanoparticles (SPIONs) on arbitrary trajectories observable by microscopy. The movement of the particles is simply controlled by an almost force-free rotation of cylindrical arrangements of permanent magnets. The same instrument can be used to move suspended cells loaded with SPIONs along with predetermined directions. Surprisingly, it also allows for controlled movements of intracellular compartments inside of individual cells. The exclusive use of permanent magnets simplifies scaled up versions for animals or even humans, which would open the door for remotely controlled in vivo guidance of nanoparticles or micro-robots.

Penurunan konsumsi bahan bakar pada mesin bensin 4 langkah 1 silinder dengan menggunakan medan magnet elektomagnetik

The quality of gasoline fuel is very important; therefore scientists are trying hard to improve the quality of this fuel. One of them is treating the fuel before it enters the combustion chamber or before experiencing the combustion process. The use of permanent magnets can reduce fuel consumption, and reduce exhaust emissions. This study aims to investigate the reduction of fuel consumption of a single-cylinder four-stroke gasoline engine by using electromagnetic field. Diameter and length of the copper wire used are 0.7 mm and 80 meters. The effect of the magnetic field on the engine performance was observed at various engine speed, such as 1500, 3000, 4500 and 6000 rpm. The results showed that the electromagnetic of solenoid winding reduced the specific fuel consumption. The percentage of reduction in the specific fuel consumption is 18.93%.

Improvement of Torque Performance and Energy Density of PM-Type Vernier Motor Utilizing Saddle Coil and Salient Pole

In electric motors, the use of rare-earth magnets has been increasing rapidly. A stronger magnet force of the magnet enables the motor’s higher performance, resulting in the most high-performance motors generally using rare-earth magnets. However, these magnets have two crucial disadvantages: the potential restrictions on the supply of rare-earth magnetic materials and the sharp fluctuation in price. Thus, many recent researches focus on developing high-performance electric motors and reducing the use of critical rare-earth magnets. By increasing the torque density of the motor, we can reduce the use of permanent magnets. Focusing on this point, and we presented a double half permanent magnet (DHPM)-type vernier motor. This paper proposed a new saddle coil permanent magnet vernier motor with improved performance compared to its predecessor. The main feature of the proposed motor is that the permanent magnet and coil in the stator of a DHPM-type vernier motor is replaced by salient poles and saddle coils, respectively. We also investigate its characteristics through various simulations.

Research of heat mode of linear permanent magnetmotor for Long –Way one stage piston compressor

The paper discusses one of the design stages of an electrical complex of a linear motor of a low-speed long-stroke piston compressor based on a permanent magnet synchronous motor (SMPM). The article concernswith studying the thermal regime of the magnetic system. The temperature regime up to 800 Cis the limitation for the use of permanent magnets of the N40 series based on the NdFeB alloy, consequently the problem of determining the amount of heat released by the winding is urgent. To study the thermal regime, a prototype of a linear permanent magnet motor was developed and tested with a long-term current flow of 5 A. The efficiency of using a sectioned winding divided into eight coils especially whenthe coils switchedin two pairs is shown.

Performance Comparison of AFDS PMSG During Voltage Regulation by Mechanical Field-weakening in Extended-speed-range

Background: Axial-flux permanent magnet synchronous generators (AFDS PMSG) have been found suitable in wind energy conversion system and electric vehicle owing to its compactness, high torque capability at low speed, high torque to inertia ratio, modular geometry, and high magnet usability index. Such applications require the generator to operate in Extended Speed Range (ESR). In ESR, voltage regulation is achieved by generator field-weakening. Usually, negative daxis current is injected in the armature winding of the generator to achieve field-weakening. However, in the axial-flux machine field-weakening by current injection is not substantial due to the low inductance of the machine and use of permanent magnets with high coercivity. We have revised all patents related to field-weakening methods applied to axial-flux permanent magnet generators. Methods: Therefore, this paper emphasizes field-weakening using mechanical methods. This paper compares the performance of AFDS PMSG topologies based on its mechanical-field-weakeningbased voltage regulation capability. In this paper, generator field-weakening is achieved by angularly displacing, one of the stators with respect to the other via a mechanical actuator. Results: The experimental results show that during voltage regulation of the DS PMSG with perfectsinusoidal back-emf characteristic, least amount of harmonics is injected in the generated output power. Conclusion: Thus, the same is best suited to design an automotive generator based on MFW method for wind energy conversion system and electric vehicle running in ESR.

ИССЛЕДОВАНИЕ ЗАКОНА РАСПРЕДЕЛЕНИЯ СИЛ ВЗАИМОДЕЙСТВИЯ МЕЖДУ ОПЫТНЫМИ ОБРАЗЦАМИ ПОСТОЯННЫХ МАГНИТОВ И МАГНИТНЫМ ОТРАЖАТЕЛЕМ, ИХ ИДЕНТИФИКАЦИЯ ПО КРИТЕРИЮ ОДИНАКОВОЙ ОБЪЕМНОЙ НАМАГНИЧЕННОСТИ

Актуальность темы исследования обусловлена тенденцией к применению постоянных магнитов в конструкциях электромеханических преобразователей, которая выражается в многополюсном исполнении синхронных магнитоэлектрических машин, работающих в генераторном и двигательном режимах [1, 2]. В статье представлено совершенствование методики идентификации постоянных магнитов, приведенной в [3] на основе исследования закона распределения магнитных сил взаимодействия между опытными образцами постоянных магнитов и магнитным отражателем на соответствие нормальному закону распределения по критерию согласия Пирсона. Показана возможность использования методов и свойств нормального закона распределения при решении вопроса идентификации постоянных магнитов с одинаковой объемной намагниченностью и выборки постоянных магнитов из опытной партии для разработки и создания магнитоэлектрических машин различного назначения.

Fast and Comprehensive Online Parameter Identification of Switched Reluctance Machines

The switched reluctance machine has been an attractive candidate for many applications owing to its simple design and low construction costs, without the use of permanent magnets. However, the double saliency of its stator and rotor poles results in noise-causing torque ripples. And although advanced torque ripple minimization control techniques exist, they rely on modeling the machine, which in turn requires specialized offline experimental setups or online (during operation) parameter identification techniques. To date, existing online techniques are iterative without proof of convergence, do not provide all model parameters, and/or rely on a priori information that can change after the machine is commissioned. In this work, an online parameter identification method is developed with a new empirical model of its flux linkage and electromagnetic torque, to provide a complete nonlinear model of the machine. With two seconds of data collected online, all electrical and mechanical parameters are identified using a non-iterative algorithm, and so it does not pose a risk of divergence. Therefore, parameter identification can be reliably and frequently carried out at different operating conditions as the machine ages for diagnostics. Also, the resulting model is designed to be used by advanced torque ripple minimization control techniques. The implementation procedure is detailed along with simulation results to demonstrate its efficacy.

Analysis of Magnetic Levitated Savonius Wind Turbine

Vertical axis wind turbine is one of the types of savonius wind turbine; VAWT generates huge twisting moment when running under lower speed by wind. Savonius wind turbine is the self-starting turbine; it uses magnetic levitation principle to get high rotational speed for the Generator. Magnetic Levitation is the phenomenon in which anything can freely suspend in the air without any support with opposed of gravitational energy. This magnetic levitation occurred due to the repulsion between the two symmetrical poles. The strong levitation is occurred with the use of permanent magnets. This type of model is to show its greater efficiency in varying wind conditions as compared to the conventional horizontal axis wind turbine and contribute to steady growing popularity for the purpose of increased utilization in the recent future as a reliable source of power generation.

Design, development and characterization of tunable Permanent Magnet Quadrupole for Drift Tube Linac

Bhabha Atomic Research Centre, Trombay is developing LEHIPA (Low Energy High Intensity Proton Accelerator) as pre-injector for 1 GeV proton accelerator for proposed ADSS (Accelerator Driven Sub-critical reactor System). LEHIPA is 20 MeV, 30 mA room temperature accelerator and consists of RFQ (Radio Frequency Quadrupole) and DTL (Drift Tube Linac) as major accelerating structures. The RF (Radio Frequency) design of DT (Drift Tube) of DTL aimed at maximizing the shunt impedance; this demands the size (transverse) of DTs to be minimal. The width of the DT is governed by the β of the particle and trade-off between transit time factor and effective accelerating voltage in the DT gap. The availability of limited volume in DTs for housing magnetic quadrupole has motivated the use of permanent magnets for generating the quadrupole field, as they have high magnetic energy density when compared to conventional electromagnets. With usage of permanent magnets, joule heating is eliminated, this helps in limiting the heat load. DTL has copious microwave heat with heat flux as large as 10 W/cm2 at certain locations. The beam dynamics requires uniformity of integral magnetic field gradient of PMQ (Permanent Magnet Quadrupole) to be better than ±0.5% with nominal value of 2.05 T. Further the drift tubes which houses these PMQs have microwave heat generation on outer surface which ranges from 5 kW to 8 kW depending on the size of the DT. This heat is required to be removed, not doing so would result in resonant frequency detuning in DTL cavity and enhanced temperature would deteriorate the strength of permanent magnets of the PMQ, thereby compromising their focal length. The drift tube has hydraulic circuit for microwave heat removal. This paper describes the magnetic design of the PMQ using Sm2Co17 rare earth permanent magnets. Paper discusses the magnetic design for optimizing integral magnetic field gradient (integral Gdl) uniformity. A novel magnetic field tuning technique is used for tuning the integral magnetic field gradient to required value. Comprehensive magnetic tuning and characterization scheme is presented which relates the measured magnetic moment of the permanent magnets, un-tuned integral Gdl and pole length to the required integral Gdl. Based on this scheme thirty six PMQ embedded drift tubes have been developed. Paper also details the results of characterization of twenty PMQs which forms part of 10 MeV to 15 MeV DTL. The scheme used for tuning integral magnetic field gradient is universal and can be implemented in similar permanent magnets quadrupoles and other permanent magnet based systems.

A low-power prototype of contactless field power controlled BLAC and BLDC motors

AbstractIn this paper, a new design configuration has been proposed in which a prototype of resonant inductive power transfer-based contactless power transfer to wound rotor has been developed which provides field power to brushless alternating current (BLAC) or brushless direct current (BLDC) motors without the use of permanent magnets in the rotor. Further, wound field in the rotor of DC motor can be powered without carbon brushes. The proposed design facilitates motor performance improvement by adding an extra dimension of field flux control, while the armature circuit is conventionally fed from position detection and commutation schemes. It contains a primary multilayer concentrated coil fed with high-frequency resonating AC supply or switched mode supply. A single layer helical secondary coil coaxially fixed on the shaft receives high frequency wireless AC power transmitted from primary coil. Fast rectifier inside the hollow shaft and DC filter provides the transferred DC power to field terminals in the rotor. It has been verified that rotor power can be varied linearly with linear variation in input DC power with the highest efficiency at the resonant frequency. Available power to the rotor remains invariable with rotational speed and angle, which is a necessary requirement for rotor field. DC voltage on the rotor terminals can be effectively controlled during standstill as well as during rotation at any speed.

Simulation of Penning ion source with optimized beam extraction system for tagged neutron tube

The magnetic field structure of the Penning ion source has been optimized with the use of permanent magnets. The ion source has been designed for small sealed tagged neutron tube. By using CST Studio Suite, the magnetic field profile inside the ion source was simulated and a variety of magnetic system was designed to improve the magnetic field uniformity of the Penning ion source and to increase the neutron yield. And the simulation results were compared with the experimental data to verify the correctness of the model. A new type of ion focusing system was devised by using the characteristics of conducting magnetic and consolidating magnetic of different metallic materials. There is more uniform magnetic field distribution and less material for the structure of 6-ring magnets placed outer anode than the structure of cylindrical magnet below the cathode. Stainless steel is selected as the material of the new extraction system after comparing the magnetic relative permeability of several materials. The new system has obvious focusing effect on the ion beam. It is also easy to obtain a small beam spot with 1 mm radius suitable for the tagged neutron tube and the extraction electrode voltage gets lower than original voltage. The results can provide reference for the improvement of the tagged neutron tube.