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This paper aims to find an approach that achieves constant output power and transfer efficiency in an open space, such as charging pads.

In this study, a topology of the five-coil system including two transmitting coils is presented. Also, in a fixed-frequency mode and an open space, this study focuses on the two transmitting coils to achieve the uniform magnetic field and ultimately, attain the constant output power and transfer efficiency.

In a fixed-frequency mode and an open space, the constant output power and transfer efficiency is then achieved in experiments by inserting the relay loop into the uniform magnetic field.

An approach that achieves constant output power and transfer efficiency in an open space. The topology of the five-coil magnetically coupled resonant-wireless power transfer (MCR-WPT) system shows prospective value for various applications, which could be used at designing of wireless battery charger dedicated for cars or mobile phones.

By comparing the simulation and experimental results, the topology can be optimized in the transmission performance by itself. By doing so, the constant output power and transfer ef?ciency are achieved in the constant frequency mode.

Magnetic resonance is becoming a routine analysis for many applications. Present day devices include active shielding systems instead of passive ferromagnetic shields. This calls for sophisticated design techniques able to provide satisfactory performance in terms of central field homogeneity, reduced stray field and minimal superconductor’s volume. In the paper some of the possible techniques to deal with such a problem are presented and discussed.

Helical coil electromagnetic launchers (HEMLs) using motion-induced commutation strategy solve the problem of synchronization control perfectly. HEMLs can meet the requirements of multiple applications such as the electromagnetic catapult, electromagnetic mortar and high-velocity coilgun. The trade-off between the velocity and efficiency is an important basis for these different applications. To optimize such objectives before actual design, the purpose of this paper is to focus on the efficient and flexible calculation model and algorithm. A novel structure of HEML is proposed after the transient simulation by this algorithm, which can improve the energy conversion efficiency and suppress the muzzle arc without affecting the velocity too much.

The equivalent circuit model of the launcher is established and the governing equations are derived. A combination of the four-stage Runge–Kutta method and the trapezoidal quadrature formula are used to solve the governing equations.

With smaller number of turns in the coils of HEML, the velocity is larger and the efficiency is lower. The non-uniform HEML is an effective option to improve the energy conversion efficiency and to suppress the muzzle arc with almost the same muzzle velocity as the conventional HEML.

The paper presents a common model and a flexible fast numerical method which can be used in multi-objective optimization of HEMLs such as the genetic algorithm. A new structure of the non-uniform HEML is proposed to improve the energy conversion efficiency and to suppress the muzzle arc of the launcher.

To design an optimal active shield for the mitigation of the magnetic stray field around an induction heating device.

The active shield consists of several compensation coils in series and generates a counter field opposite to the main field. One extra compensation winding – the “generating compensation winding” (GCW) – is positioned close to the excitation coil and works as the secondary winding of a transformer. The power in this winding is used to drive the other compensation coils (the active shield), which are the load of the transformer. A circuit with passive components is inserted between the GCW and the other compensation coils. The shield is optimal if it achieves a high field reduction, while the energy dissipation is low. By using a genetic algorithm (GA) that minimizes an objective function, the optimization algorithm finds the optimal geometry and the optimal current for the GCW and the other compensation coils. The objective function uses time harmonic and axisymmetric finite element calculations.

The transformer driven active shield reduces the magnetic field effectively. It is cheap and easy to build, but it works well only for one frequency.

The shield is sensitive to tuning of the passive circuit and to changes in the frequency of the induction heater.

This transformer driven shield is an alternative for the classical active shield with external power supply.

An active shield that does not need an external power supply is a cheap solution for the shielding of magnetic fields.

The unilateral axle counting sensor is an important railway signal device that detects a train. For efficient and stable detection, the amplitude of induced electromotive force and its changes must be big enough. Therefore, the purpose of this study is to find a way to design and optimize the sensor structure quickly and accurately.

With the help of extensive electromagnetic field calculations, the study puts forward a modified model based on the finite element method, establishes an independent air domain around the sensor, wheel and the railway and adopts a unique grid division method. It offers a design optimization method of the induction coil angles and its spatial location with respect to the excitation coil by using the combination weighting algorithm.

The modified modeling method can greatly reduce the number of finite element mesh and the operation time, and the method can also be applied to other areas. The combination weighting algorithm can optimize the structure of the sensor quickly and accurately.

This study provides a way to design and optimize the structure of the sensor and a theoretical basis for the development. The results can improve and expand the technology of the axle counting sensor.

Linear oscillatory actuators have been used in a wide range of applications because they have a lot of advantages. Additionally, multi-degree of freedom resonant actuators have been developed. The purpose of this paper is to propose a novel three-degree-of-freedom resonant actuator resonant actuator that is driven in three directions. The dynamic characteristics are clarified through finite element analysis and measurement.

A novel three-degree-of-freedom resonant actuator resonant actuator consists of a cross-shaped mover, a stator and five excitation coils. The magnetic structure of this actuator is geometrically similar to that of general permanent magnet synchronous motor. Therefore, vector control is applied to this actuator. The dynamic characteristics are analyzed and measured.

Computed results show that the proposed actuator is able to be independently driven in three directions. However, measured result show that mutual interference is severely observed because of the structure of the mover support mechanism. Therefore, the structure needs to be improved.

The proposed actuator has originality in its structure and operating principle.

Part 2 of this article appeared in the February issue. Basic principles were explained, followed by a description with illustrations of the various methods which could be used to produce flux in the required direction. This part will deal mainly with the values used in magnetic particle testing, the different current wave forms with a discussion on the advantages and limitation of each. A short abbreviated table of values used in various standards and codes is also included for comparison.

The inverse problem related to eddy current testing (ECT) is often formulated as a shape optimization problem. The purpose of this paper is to propose a methodology for determining the optimal parameters of a sensor system for more accurate reconstruction of the crack shape.

In this paper, an objective function is formulated using the shape sensitivity information computed from the ECT data. The design of a non‐destructive testing (NDT) sensor is carried out through optimizing the sensor parameters under such a criterion.

The methodology proposed results in modifications to the original sensor geometry which makes it more sensitive to the depth changes in a crack. A square wave form of excitation is used in order to provide more information on the size of the crack at different depths, essentially through the superposition of a range of excitation frequencies, each of which has a different depth of penetration. The newly designed ECT sensor system is suitable for dealing with the natural crack problem.

While the methodology is general and has been shown to work in a simulated environment, the result is not verified by the experiments because the newly designed device has not actually been fabricated.

This paper has demonstrated the possibility of designing a sensor probe using computer aided design tools without extensive physical testing. The design process is novel and based on a sensitivity approach. This is shown to be very efficient and effective and the solution of the inverse problem demonstrates a very fast convergence.

There are several techniques for producing a magnetic field, one of which is the magnetic flow technique.

The purpose of this paper is to present the basic ideas of magnetic nanoparticles' usage in the breast cancer treatment, which is called magnetic fluid hyperthermia. The proposed approach offers a relatively simple methodology of energy deposition, allowing an adequate temperature control at the target tissue, in this case a cancerous one. By means of a numerical method the authors aim to investigate two heating effects caused by varying magnetic fields, i.e. to compare the power density heating effects of eddy currents and magnetic nanoparticles.

In order to numerically investigate the combination of the overheating effect of magnetic nanoparticles and eddy currents, the Finite Element Method solver based on FEniCS project has been prepared. To include the magnetic fluid in the model it has been assumed that power losses in the magnetic nanoparticles are completely converted into heat, according to experimentally developed formula. That formula can be interpreted as the hysteresis losses with regard to the volume of magnetic fluid. Finally, the total power density has been calculated as the product of the sum of power density from eddy currents and hysteresis losses. That methodology has been applied to calculate the effectiveness of magnetic fluid hyperthermia with regard to the female breast phantom.

The paper presents the methodology which can be used in magnetic fluid hyperthermia therapy planning and Computer Aid Diagnosis (CAD). Furthermore, it is shown how to overcome one of the most serious engineering challenges connected with hyperthermia, i.e. achieving adequate temperature in deep tumors without overheating the body surface.

The obtained results connected with the assessment of eddy currents effect suggest that during hyperthermia treatment the configuration which consists of an exciting coil and human body, plays a curial role. Moreover, the authors believe that these results will help to predict the skin surface overheating that accompanies deep heating. The presented methodology can be used by engineers in the development of Computer Aid Diagnosis systems.

In a given patient's situation a number of choices must be made to determine the parameters of the hyperthermia treatment. These include the need of multiple‐point temperature measurements for accurate and thorough monitoring. Treatment planning will require accurate characterization of the applicator deposition pattern and the tissue parameters, as well as the numerical techniques to predict the resultant heating pattern. The presented paper shows how to overcome these problems from the numerical point of view at least.