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Techniques of synthesis of RE diborides (RB 2 ) are developed (R=Tb, Dy, Ho, Er, Lu). Temperature dependence of magnetisation, a heat capacity, a lattice parameters of diborides in the range of 2–300 K are measured. According to joint calorimetric and X-ray research the analysis of a phonon component of a heat capacity and thermal expansion of RE-diborides is carried out by Debye-Einstein's models, the parameters of the model are determined. The change of magnetisation of the ferromagnetic RB 2 compounds with growth of temperature caused by violation of ordering in the system of the atomic magnetic moments is compared with the change of entropy of a magnetic subsystem calculated from calorimetric data. Analytical expansion for calculation of a magnetic component of a heat capacity by RB 2 magnetisation data at the temperatures of 2–300 K is obtained.

Metasurfaces are powerful platforms for controlling light, with bandwidth and efficiency being the two key parameters. Here conventional transmissive metasurfaces suffer, because they rely on multipoles of different resonant nature to construct Huygens sources. The authors explore the possibility of utilizing congener dipoles (solely electric, without a magnetic component) with similar resonant properties to release these constraints. Beam deflection and focusing, over a broad wavelength band and with high efficiency, are demonstrated. This approach extends the design methodology and improves the performance of metasurfaces.

Critical materials (CMs) are vital to modern technology. Components of modern vehicles can be recycled to recover and reuse the CMs to help ensure a supply of these materials. Electronic components from a 2015 GMC Sierra truck (21 components) and 2016 Toyota Camry sedan (10 components) were analyzed for CMs. The components were processed via size reduction, aqua regia leaching and dissolution, and final solutions were analyzed for metal content. It was found that most electronic components of both vehicles contain CMs. The most concentrated CMs in the components were Sn, Nb, and Tb. Nd and Co were found in several of the magnetic components. CM economic value was found to be low compared to the overall value of the components, and the CM content would not allow for a viable pathway for recycling. Remanufacturing of components may be a more economic option of reuse in the future.

Since the declaration of rare earths as “critical materials” by the U.S. Department of Energy in 2011, the design of rare earth-free permanent magnets has been an actively focused area of research. Nanomaterial synthesis techniques have allowed rational engineering of magnetic composite materials which approach the requirements for maximized magnetic energy. Here, recent significant advances in chemical and physical syntheses of nanostructured permanent magnets are described, for both single-phase hard magnetic materials and for hard/soft exchange-coupled nanocomposites. This chapter focuses on the engineering of nanocrystalline rare earth and rare earth-free magnets. New discoveries which will guide the design of future materials are also detailed, including the importance of dipolar interactions between magnetic components, techniques in bottom-up nanocomposite engineering, and tolerance of materials to higher operating temperatures. A brief outlook for the next stage of magnetic nanomaterials research is given in the concluding section.

Quantum droplets can emerge in bosonic binary magnetic gases (BMGs) from the interplay of short- and long-ranged interactions, and quantum fluctuations. We develop an extended meanfield theory for this system and use it to predict equilibrium and dynamical properties of BMG droplets. We present a phase diagram and characterize miscible and immiscible droplet states. We also show that a single component self-bound droplet can be used to bind another magnetic component which is not in the droplet regime. Our results should be realizable in experiments with mixtures of highly-magnetic lanthanide atoms., Comment: 5 pages, 4 figures

In this work, we compare the effects of electromagnetic (EM) fields on strong coupling systems in two formalisms: in-out and in-in, which are different from each other when a finite electric field is present. The chiral effective Nambu–Jona-Lasinio model is adopted for this study, and two kinds of EM field distributions are considered: pure electric field and parallel EM (PEM) field with equal electric and magnetic components. For both distributions, we find that the results of in-out and in-in formalisms start to diverge when the electric field (qE)1/2 is larger than the chiral effective mass M=[m2+(π0)2]1/2, that is, when the Schwinger pair production mechanism becomes important. Besides, the chiral restorations are stiffer in the in-in formalism, especially the transition shifts to first-order instead of the second-order for the PEM field. The neutral collective modes are also explored accordingly: For the PEM field, more precise calculations show nonmonotonic features of their pole masses due to parity mixing, and then the Goldstone-like mode is found to be noneffective at the end of chiral rotation because of chiral anomaly.

International audience; This work proposes an improvement for the consideration of ac winding losses in the design process of inductors to be employed in power converters, where the geometrical parameters of the inductors are not known before starting the design. The presented method consists of the pre-computation of a homothetic multivariate regular grid surface by finite element simulations, from which the winding resistance can be obtained by direct multivariate linear interpolation. Special attention is given to Dowell's analytical formulations. These are often used in the design but typically with little details given on how the final expressions are derived. The results with the new method are shown to be more accurate than the analytical calculations over a wide range of design points and, thus, are a useful design tool.

The performance of Magnetorheological dampers should be analyzed to study the stability of Magnetorheological fluid and its configuration. To this end, in this study a prototype Magnetorheological fluid is presented. The fluid consists of stabilized Silicone dioxide (SiO2) nanoparticles, Stearic acid, Phosphoric acid and micron-sized soft ferromagnetic carbonyl iron particles. To assure the authentic performance, sedimentation and magneto-rheometry tests are conducted. Also, a prototype of double-tube Magnetorheological damper with double magnetic components is fabricated by using the mentioned magnetorheological fluid characteristics. Damping force measurement test is carried out to measure the damping force in various electrical currents. The Kwok model is employed to examine the analytical model predictions against the experiments. Furthermore, a general evolution is presented using the neural network algorithm. It is demonstrated that the damping force in saturated current is almost five times higher than in the zero current. In addition, the derived evolution for the damping force has a high performance to predict the response of the Magnetorheological damper in other electrical currents.

Mn-Zn cores are widely used in high-frequency, high-power power electronics applications. In order to manage with kilowatt and even higher power ratings, large cores are required. In this issue the magnetic cores themself are affected by inherent physical parameters, and thus their performances are limited and additional losses are generated. This phenomenon can be summarized as the dimensional effect. It includes eddy current effect and resonance effect. The eddy current effect has been widely discussed, but the resonance effect is often neglected. But both effects causes considerable losses in certain sizes and at certain frequencies. Therefore in this paper, a review of the existing researches about dimensional resonance effects is presented.

We propose a theoretical model for a magnetically-actuated artificial cilium in a fluid environment and investigate its dynamical behaviour, using both analytical calculations and numerical simulations. The cilium consists of a spherical soft magnet, a spherical hard magnet, and an elastic spring that connects the two magnetic components. Under a rotating magnetic field, the cilium exhibits a transition from phase-locking at low frequencies to phase-slipping at higher frequencies. We study the dynamics of the magnetic cilium in the vicinity of a wall by incorporating its hydrodynamic influence, and examine the efficiency of the actuated cilium in pumping viscous fluids. This cilium model can be helpful in a variety of applications such as transport and mixing of viscous solutions at small scales and fabricating microswimmers.

Electronic transformers SST (Solid State Transformer) working on HF (high frequency) have relatively large additional costs to manufacture power converters, however this is compensated by significantly lower expenditure on magnetic components. It should be emphasized that the total mass of energy transfer systems with increased frequency, at a given power, is much lower than transformers operating at 50Hz. This is particularly important in mobile devices powered from grids or DC traction networks, such as systems for powering their own traction vehicles, various types of mobile test stations, power systems for executive systems in airplanes, as well as equipment for the army. In these solutions, the weight and dimensions of the devices are often more important than the cost and may determine the possibility of their use in the aforementioned applications. Designed as part of the device, which includes DC / DC converters in the DAB system (Dual Active Bridge), they have a wide range of applications and will form the basis for the construction of 10 kW DC car chargers.

Catalysis benefits from biomimetic materials with sophisticated structures because a variety of functions can be integrated into one structure, satisfying the demands of a diverse range of applications. Magnetic catalysts have been widely used in various applications, but the magnetic components are most commonly used for recycling. In this study, we report the fabrication of magnetic nanocatalysts composed of a support of magnetic nanobars and Ag nanoparticles confined between two silica layers. Notably, the catalysts are constructed as nanoscale stirring bars that are able to generate disturbances at this scale. More importantly, the catalysts can be applied in both macro- and micro-systems, effectively addressing the conventional mixing method. The catalysts can then be conveniently separated from the system after use. The performances of magnetic nanoscale catalysts are well maintained through recycling.

The book chapter shows that it is rare for soft magnetic materials in a.c. applications to be subject to perfectly sinusoidal flux-density waveforms. The designers and users of electrical machines are placing increasing demands on the magnetic cores. Traditionally, the electrical steels used in these devices are characterised under standard conditions with power frequency sinusoidal magnetisation requiring designers to over-engineer the magnetic components based on previous experience. It is common knowledge that many applications of electrical steels exhibit flux density waveforms which are far removed from the sinusoidal ideal. Even for conventional, sinusoidally excited, devices such as induction motors, the flux density waveforms vary from close to sinusoidal to highly distorted and, behind the teeth, rotational flux conditions.

This chapter discusses the production and applications of iron powder and ferrite magnetic cores. More recently, iron and SiFe bulk components have been developed and commercialised for applications requiring mass produced, cheap, mechanically strong and dimensionally accurate net shape cores for magnetic components. These iron and silicon iron compressed components are commonly referred to as soft magnetic composite (SMC) cores or consolidated powder cores. General advances in powder metallurgy have resulted in their applications in many sectors, particularly as functional materials, replacing laminated cores for small motors and actuators in the automotive and aerospace industries. The authors focus on the magnetic properties of these cores such as magnetisation, magnetic permeability and loss components.

The power electronics world made a big step in higher efficiency by introducing Gallium-Nitride (GaN) and Silicon-Carbide (SiC) electronic switches. The fast switching time and high voltage capabilities with low losses bring new opportunities for the optimization of magnetic components. For the majority of power electronics designers, the impression is that core material manufacturers are not innovative and the industry is making slow progress with the development of more efficient materials. The keynote and this paper will demonstrate that progress is indeed being made, as better materials become available while expanding on their limitations.

Magnetic components are usually assumed relatively reliable in power electronic converters. Nevertheless, with the trend for ever-increasing power density, planar magnetics may need to be designed with reduced margins in terms of thermal and insulation. Wear out or even failure of magnetic components may become an issue in extreme design and operation scenarios. This paper presents the first observations in degradation testing of planar magnetics at high temperatures. It serves to investigate the change of various parameters and identify possible ones as the health indicators of magnetic components for power electronic applications. The degradation testing and characterization results are presented and interpreted.

In power electronics, the tendency to increase power and frequency (in the range of several MHz) has become an actual concern and leads to challenging design of the magnetic components. The traditional design methods need to be adapted to this demand, since high frequency effects in the core behavior need to be considered, and parasitic elements play a key role. In this paper, a new design method for high-power and high-frequency transformers is proposed. FEA tools and semi-empirical approaches are used to achieve an accurate estimation of losses, parasitic capacitance and temperature. A class-D Push-Pull 13.56 MHz, 2 kW transformer for space applications is built as an example to validate the method.

An accurate power loss model, for the design of high-efficiency switching power supplies, is difficult to establish due to the complicated magnetic components where the power loss is hard to calculate. This paper proposed a multi-level power loss model of LLC circuits with a planar transformer of high frequency, high power, and low voltage output. The key loss items can be optimized by using this loss model, the accuracy of which and the feasibility of the optimization method are validated by extensive prototype experiments. The experimental results show that the average accuracy of the loss calculation is about 93.6%, and the high efficiency at high-power conversion (95.9% @ 3 kW, 224–16 V) has been realized using an optimized prototype converter.

The 2D Maxwell eigenproblems are studied from a new point of view. An electromagnetic problem is cast from the Lagrangian system with single variable into the Hamiltonian system with dual variables. The electric and magnetic components transverse to the wave propagation direction are treated as dual variables to each other. Higher order curl-conforming and divergence-conforming vector basis functions are used to construct dual vector spectral elements. Numerical examples demonstrate some unique advantages of the proposed method.

In this paper we apply Cosserat rod theory to catheters with permanent magnetic components that are subject to spatially varying magnetic fields. The resulting model formulation captures the magnetically coupled catheter behavior and provides numerical solutions for rod equilibrium configurations in real-time. The model is general, covering cases with different catheter geometries, multiple magnetic components, and various boundary constraints. The necessary Jacobians for quasi-static, closed-loop control using an electromagnetic coil system and a motorized advancer are derived and incorporated into a visual-feedback controller. We address the issue of solution bifurcations caused by the magnetic field by proposing an additional, stabilizing control method that makes use of system redundancies. We demonstrate the effectiveness of the model by performing 3D tip-position trajectories with root-mean-square distance errors of 2.7 mm in open-loop, 0.30 mm in closed-loop, and 0.42 mm in stabilizing closed-loop modes. The stabilizing controller achieved on average a factor of 1.6 increase in the restoring wrenches for the least stable direction.

The latest breakthroughs in the synthetic preparation of nanomaterials have led to an expanding library of novel, complex and shape controlled structures with unique characteristics. Anisotropic Janus particles (JPs) are asymmetrical and are able to endow diverse chemical and physical characteristics with directionality within a single particle. They are typically distributed into three classes, viz polymeric, inorganic and polymeric-inorganic and is made in a variation of morphologies including spherical, mushroom, snowman shaped, rod or cylindrical. Herein, we focus on JPs with a magnetic component, with emphasis on their fabrication, unique characteristics and recent applications.

The Z-Axis tipper electromagnetic (ZTEM) technique is based on a frequency-domain airborne electromagnetic system that measures the natural magnetic field. A survey area was divided into several blocks by using the Maxwell’s equations, and the magnetic components at the center of each edge of the grid cell are evaluated by applying the staggered-grid finite-difference method. The tipper and its divergence are derived to complete the 3D ZTEM forward modeling algorithm. A synthetic model is then used to compare the responses with those of 2D finite-element forward modeling to verify the accuracy of the algorithm. ZTEM offers high horizontal resolution to both simple and complex distributions of conductivity. This work is the theoretical foundation for the interpretation of ZTEM data and the study of 3D ZTEM inversion.

Two profiles have been sampled from the Nubia Sandstone at Aswan, south Western Desert: the 1st profile has been taken from Abu Aggag Formation and the 2nd one was from Sabaya Formation (23.25 °N, 32.75 °E). 136 oriented cores (from 9 sites) have been sampled. Abu Aggag Formation is of Late Cretaceous (Turonian) and Sabaya Formation is of early Cretaceous (Albian–Cenomanian). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment. It has been found that hematite is the main magnetic mineral in both formations. Four profile sections from Abu Aggag Formation, yielded a magnetic component with D = 352.7°, I = 36.6° with α 95 = 5.2° and the corresponding pole lies at Lat. = 82.8 °N and Long. = 283.1 °E. Five profile sections from Sabaya Formation, yielded a magnetic component with D = 348.6°, I = 33.3° with α 95 = 5.8° and the corresponding pole lies at Lat. = 78.3 °N and Long. = 280.4 °E. The obtained paleopole for the two formations lies at Lat. = 80.5 °N and Long. = 281.7 °E. The obtaind magnetic components are considered primary and the corresponding paleopole reflects the age of Nubia Sandstone when compared with the previously obtained Cretaceous poles for Egypt.

Use of a beam-based approach is presented for establishing a rigidity calibration for the A1900 fragment separator located at the National Superconducting Cyclotron Laboratory. Also presented is why an alternative approach to the rigidity calibration – using detailed field maps of individual magnetic components – is not a feasible basis for deriving an accurate calibration. The level of accuracy achieved for the rigidity calibration is ±0.1%.

Static three-axis alternating field (AF) demagnetization is the most common method regularly implemented for removing magnetic components of rock samples. This method is so widely used that one of its main limitations, the acquisition of gyroremanence (GRM), is often not accounted for or even discussed. The presence of GRM likely interferes more than is recognized in accurate determination of the most stable remanence. The accepted method proposed by Dankers and Zijderveld (1981) for excluding GRM affected measurements requires nearly triple the amount of lab work, and by consequence, is almost never regularly implemented on large batches of samples. Here, we present a laboratory procedure and subsequent analysis (SI method) that removes the effects of GRM in static AF demagnetization without requiring extra laboratory work. This paper, therefore, describes a new standard protocol for efficient static AF demagnetization of rocks.

The characteristics and geoeffectiveness of interplanetary coronal mass ejections (ICMEs) are derived and their relationships are investigated. The results are compared for a set of events in the rising phase of Solar Cycles 23 and 24. These events are considered from the reported list of Cane and Richardson (Geophys. Res. Lett. 27, 3591, 2000). The geoeffectiveness is studied independently for ICME and sheath. The results obtained are that i) CMEs of Cycle 23 have generated a higher Dst index than Cycle 24 CMEs and that ii) the southward magnetic component ( $B_{\mathrm{s}}$ ) and the Dst index of ICMEs correlate well for both Cycles 23 and 24 in their rising phase. These findings agree with the literature, which has described Cycle 24 to be weaker than Cycle 23 and where the ICME/sheath regions of Cycle 23 are found to have a greater $B_{\mathrm{s}}$ that results in stronger storms. In addition, other results obtained are as follows: i) The relation between ICME size and the related Dst index gives a weak correlation for the rising phases of both Cycles 23 and 24. ii) The correlation between sheath size and Dst index is higher in the rising phase of Cycle 24 than in the rising phase of Cycle 23. iii) The average ICME size of the rising phase of Cycle 23 $(84~R_{\odot})$ is greater than that of the rising phase of Cycle 24 $(58~R_{\odot})$ . However, the average sheath size is $24~R_{\odot}$ , which is nearly equal to that of Cycle 24 $(26~R_{\odot})$ . Thus the differences between the properties of ICME and sheath in both the cycles are demonstrated. Nearly 75 % of geomagnetic storm peaks occurred in the ICME duration in the rising phase of Cycles 23 and 24. This shows that the ICMEs are more important in generating the storms than the sheaths in the rising phase of a solar cycle.

Cumulative qualitative and quantitative analysis of the filtered regional and residual magnetic components of the northeastern central area of the Gulf of Suez, as well as images of the second vertical derivatives of the reduced to the northern magnetic pole map of the total magnetic intensity field images, supplemented with the available geologic information, enabled the precise delineation of the detailed structural configuration of the basement complex, which consequently illustrated the structural deformational pattern of the overlying sedimentary succession. The basement tectonic map reflects a series of N–S to NNW–SSE oriented belts of high and low basement structures. These structures are interrupted by a set of NE–SW crossing diagonal faults having varying throws and creating promising blocks for exploration. An often remarkable correlation between the reduced to the magnetic pole map and the basement relief map is noted, in particular the outline of various oil fields. A larger number of the tilted fault blocks and basement culminations have been outlined and numerous interesting exploration prospects are indicated, which appear to warrant further follow up investigation.

A rGO/Nb2CTx/Fe3O4 composite with a hierarchical architecture is prepared by integrating multilayered Nb2CTx, magnetic Fe3O4 nanoparticles and two-dimensional rGO sheets. The rGO/Nb2CTx/Fe3O4 composite shows superior absorption of electromagnetic wave with a minimum reflection loss (RLmin) of −59.17 dB at 11.8 GHz with an equal absorber thickness of 2.5 mm as well as a broad effective absorption bandwidth (EAB, RL ≤ 10 dB) of 6.8 GHz. The tunable EAB can be achieved at a frequency range of 8.5 to 18 GHz by modifying the thickness of the absorber from 1.5 to 3 mm. The excellent absorption capacity of electromagnetic wave is attributed to the synergetic effects between the multiple loss mechanisms of rGO/Nb2CTx/Fe3O4 and good impedance matching. The results provide new insight into MXene-based absorbers with enhanced ability to absorb electromagnetic wave by incorporating the magnetic components and 2D rGO sheets.

This paper develops a bi-directional active equalization method using an inductor with multiple balancing paths. The new method allows the energy to transfer directly from any cell(s) to any cell(s) which can increase the equalization speed, reduce the energy conversion times and efficiently prevent the batteries from overcharging or undercharging. We adopt the bi-directional switches of low conduction loss for high equalization efficiency. To further improve the battery equalization system performance, the impact factors of the average balancing current which is the main measurement index of the balancing speed are first specifically discussed and the efficiency is also evaluated. The experiments with a four-20Ah Lithium-ion battery string are conducted and the results demonstrate that the developed approach has achieved a good overall performance of equalization.

Equivalence causes non-uniqueness in interpretations of the grounded-wire transient electromagnetic method (TEM). Many different layered models may produce the same response curves practically. However, the conventional theory of equivalence is based on the three-layer geo-electric models while the earth may not be reducible to a simple three-layer structure. Therefore, it is important to perform research on equivalence based on more complex models to reduce the uncertainty the grounded-wire TEM interpretations. Here, we extend the theory of equivalence based on a multi-layer target in the grounded-wire TEM, consisting of SS-, HH-, and TT-type. The analysis of relative error is applied to investigate the effect of measured components and receiver locations on equivalence. The results show that equivalence of multi-model occurs when any of three conditions is satisfied: the longitudinal conductance is constant in the far area, the thickness of targets do not change, or the transverse conductance of a multilayer target remains unchanged. In order to largely resolve the effect of equivalence on data interpretation, a strategy combined with short-offset survey and joint inversion of the electric component and magnetic component is presented and verified by the field survey in Shanxi Province, China.

All electronic gadgets today employ high frequency Switch Mode Power Supplies. As the number of such gadgets is increasing rapidly, the focus is on improving the efficiency of power conversion and better utilization of energy. It is always a challenge for the practicing power supply engineers to exactly apportion and evaluate the total losses in the power converters. While it is relatively easy to compute and measure the power losses in semiconductor devices, it is practically difficult to measure the power losses in magnetic components. The data sheets provided by the manufacturers, for core loss and thermal resistance, do act as a starting point in the design stage but, always the designers felt the need to know the exact power loss in the ferrite high frequency transformers and their thermal resistance values. The data sheets provide thermal resistance values only for the cores and it is necessary to quantify value for a fully wound transformers. Copper losses in high frequency transformers are very significant and too involved to compute. In this paper, we propose a simple and practical technique, which precisely depicts the actual power loss in a high frequency ferrite core transformer. With this technique various ferrite cores can be characterized for their hysteresis losses at varying flux densities and frequencies. We can also precisely compute the thermal resistance of the Ferrite transformers.

The use of magnetic components in power electronics is becoming more and more demanding, as well as control systems are pushing these devices to work in precise working points of the magnetic characteristic. These control techniques improve the performance of the power device but force the designer to simulate more and more pushed. It is therefore necessary to find ways to model the magnetic properties of the materials used in order to perform accurate simulations. In this article is proposed a way to realize the model through equivalent circuits and applied to the study of a series of components (inductors, transformers, etc.) intended for power electronics.

Medium modification observables for high transverse momentum hadrons serve as the hard probe of the evolution history of the QCD matter produced in such collisions, as well as its constituent. CUJET/CIBJET framework is a sophisticated simulation tool that allows the quantitative soft-hard event engineering study. In this chapter we introduce the details of CUJET/CIBJET framework, in particular how elastic and inelastic energy loss is simulated, via collisions with chromo-electric and magnetic components.

BMKG has observations of earth’s magnets which are scattered in Indonesia. The BMKG earth magnetic sensor produces real-time data output. This research focuses on predictive maintenance models on earth magnetic sensors based on data output. The resulting data output is in the form of a delimited format in the form of spaces so that it is easy to process. The magnetic component used is the total component data (F) from the earth’s magnetic sensor. Data processing using python scripts with the algorithm used is the random forest method by comparing the resulting value difference to find out whether the data generated is still in tolerance or not. The results of the prediction model with the number of estimators 10 produce RF Score = 0.98 and MAE = 0.83.

Hybrid controlled full-bridge CLL resonant converter for wide range input voltage applications is proposed in this paper. The hybrid strategy combines the advantages of variable-frequency control (VFC) and phase-shift control (PSC). It addresses several limitations of resonant converters in the wide range input applications, such as the difficulty of optimizing of magnetic components, the large circulation loss of the converters and the difficulty of implementing of zero-voltage switching (ZVS) soft switching. Theory and experiment show that full-bridge CLL resonant converter can operate efficiently within a narrow range of switching frequencies under the hybrid control strategy. To confirm the performance of the proposed converter, experimental results are presented for a prototype with output power of 500W and a peak efficiency value of 94%.

With frequency rising, winding loss becomes the most serious part in magnetic component. There are four types of winding loss caused by non-uniform magnetic field, such as air-gap fringing loss, irrational layout of transformer loss, adjacent seam of PCB winding loss and terminal loss. In this paper, the loss mechanisms are discussed in detail and effective optimizations on these losses are proposed correspondently. Finally, a high frequency integrated matrix magnetics was successfully developed under the abovementioned winding loss optimization methodology on a server power with 12V/1000W output.

Using ULF (ultra low frequency) measurements of magnetometer and ICE (Instrument Champ Electrique) experiments on board the DEMETER satellite, possible irregularities in ULF magnetic and electric components have been surveyed in the vicinity of Samoa (29 September 2009) earthquake region. The data used in this paper cover the period from 1 August 2009 to 11 October 2009. The anomalous variations in magnetic components (Bx, By and Bz) were clearly observed on 1 and 3 days before the event. It is seen that the periodic patterns of the magnetic components obviously changed prior to the earthquake. These unusual variations have been also observed in the variations of polarization index obtained from the magnetic components during the whole period at ~10:30 and ~22:30 LT. It is concluded that the polarization exhibits an apparent increase on 1 and 3 days preceding the earthquake. These observed unusual disturbances in ULF magnetic components were acknowledged using the detected perturbations in ULF electric components (Ex, Ey and Ez) in the geomagnetic coordinate system. Finally, the results reported in this paper were compared with previous results for this Samoa earthquake. Hence, the detected anomalies resulting from the magnetometer and ICE ULF waveforms in quiet geomagnetic conditions could be regarded as seismo-ionospheric precursors.

The thermal analysis and the estimation of the maximum temperature under operating conditions is an important step in the optimization of magnetic components for power electronics. In most cases, the thermal distribution is 2D or 3D so the use of analytic equations is very complex, or even not feasible. Then Finite Element Analysis (FEA) tools are required. However, the meshing is computationally very expensive due to the high number of conductors and their small size compared to the core. The goal of this paper is to develop an accurate and fast thermal model for FEA simulations to overcome this problem. A deviation as small as 0.9% from the maximum temperature in the winding and a 7.2-fold reduction of the simulation time are achieved. The model is suitable for solid and litz wires, independently of the winding impregnation material and the core shape. Three prototypes with different core shapes and winding types are used to experimentally validate the model.

openaire: EC/FP7/339380/EU//ALEM Two-dimensional finite element analysis is a widely used tool in the design, analysis, and optimization of electrical machines and magnetic components. Although the core components of the method are relatively mature, numerous special applications are still being developed. This paper introduces an open-source library for finite element analysis in Matlab, tailored especially for electrical machines. The library is highly portable, and has a good performance. Furthermore, it provides all the basic functionality typically needed for magnetic analysis. As such, it can be used as a starting point for more advanced work.

This study is devoted to investigating the blow-up criteria of strong solutions and regularity criterion of weak solutions for the magnetic Benard system in $$\mathbb {R}^3$$ in a sense of scaling invariant by employing a different decomposition for nonlinear terms. Firstly, the strong solution $$(u,b,\theta )$$ of magnetic Benard system is proved to be smooth on (0, T] provided the velocity field u satisfies $$\begin{aligned} u\in {L}^{\frac{2}{1-r}}(0,T;\dot{\mathbb {X}}_r(\mathbb {R}^3))\quad ~~with\quad 0\le {r}0$$ is a suitable small constant, then the strong solution $$(u,b,\theta )$$ of magnetic Benard system can also be extended beyond $$t=T$$ . Finally, we show that if some partial derivatives of the velocity components, magnetic components and temperature components (i.e. $$\tilde{\nabla }\tilde{u}$$ , $$\tilde{\nabla }\tilde{b}$$ , $$\tilde{\nabla }\theta $$ ) belong to the multiplier space, the solution $$(u,b,\theta )$$ actually is smooth on (0, T). Our results extend and generalize the recent works (Qiu et al. in Commun Nonlinear Sci Numer Simul 16:1820–1824, 2011; Tian in J Funct Anal, 2017. https://doi.org/10.1155/2017/3795172 ; Zhou and Gala in Z Angew Math Phys 61:193–199, 2010; Zhang et al. in Bound Value Probl 270:1–7, 2013) respectively on the blow-up criteria for the three-dimensional Boussinesq system and MHD system in the multiplier space.

International audience; Many motile microorganisms swim and navigate in chemically and mechanically complex environments. These organisms can be functionalized and directly used for applications (biohybrid approach), but also inspire designs for fully synthetic microbots. The most promising designs of biohybrids and bioinspired microswimmers include one or several magnetic components, which lead to sustainable propulsion mechanisms and external controllability. This Review addresses such magnetic microswimmers, which are often studied in view of certain applications, mostly in the biomedical area, but also in the environmental field. First, propulsion systems at the microscale are reviewed and the magnetism of microswimmers is introduced. The review of the magnetic biohybrids and bioinspired microswimmers is structured gradually from mostly biological systems toward purely synthetic approaches. Finally, currently less explored parts of this field ranging from in situ imaging to swarm control are discussed.

Modern simulators require increased time and rigor for the analysis of modern power electronic circuits. They do not replace experimental measurements, but they support the designers, because allow to analyze various scenarios in a relatively convenient time. However, an analysis based on circuit equations is often more effective. The transient regime and the response to perturbation can be analyzed with customized interfaces and usually provide fast solutions than classic simulators. The present paper comes to analyze the case of switching sources and to justify the use of customized interfaces in concrete situations for design the magnetic components.

Advances in power conversion technologies have highlighted the need for development of new class of magnetic components (inductors, transformers etc) with lower footprint and higher efficiency. Presently, the sizes of these magnetic components have been limited due to the use of low flux density ferrite as a core material. In this paper, the assembly and working of an amorphous ribbon transformer with low loss performance as a replacement for ferrite based ones were studied. The minimum amount of power loss of the material was measured as

With increased switching frequency and multilevel topology, it is possible for a wide-bandgap (WBG) device based converter to be connected to the grid without line filters. In this paper, a high power density filter-less Photovoltaic (PV) inverter is designed and experimentally demonstrated. A design is proposed to completely remove the AC side line filters, and thereby the size and weight of magnetic components are reduced. A 100 kW three-phase two stage prototype has been built in the laboratory, which achieves a power density of 5 kW/kg, and measured CEC efficiency of 99.2%.

Magnetic integration can be introduced in contactless resonant converter with high-order compensation network, such as LCL and LCC, to reduce the number and volume of the magnetic components. However, the cross couplings among the multi-windings of the integrated contactless transformer will impair the performance of the converter. In this paper, an integrated LCL-S contactless resonant converter is proposed, and the detailed analysis including characteristics of input impedance, voltage gain, input current harmonics and capacitor stress are also given. An improved designing method to achieve a ZPA (zero phase angle) and load-independent voltage gain is presented. Finally, a 1kW prototype is built to verify the theoretical analysis. The analysis and experimental results reveal that LCL compensation with magnetic integration features lower voltage stress across the resonant capacitor.