bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of experimental uncertainties on the reconstruction reliability for CCIC cable current
Authors: Polak M. , Kvitkovic J. , Formisano A. , Martone R.
Published: December 2018

The determination of the current distribution in full-size cable-in-conduit conductor is a relevant research activity in the framework of the International Thermonuclear Experimental Reactor, aimed at optimizing the performance of the superconducting cables to be used for the machine magnets. The direct measurement of current in the cable is not possible, and inverse techniques must be used, providing only rough estimates due to the severe ill conditioning of the problem. The measurement of magnetic field in the neighbourhood of superconducting cables is the first step in the estimation of the current distribution inside them. Uncertainties in this early phase may very adversely impact the reliability of the problem solution.

In this paper we study the impact on current reconstruction of possible errors in the measurement of magnetic field of superconducting cables of Cable in Conduit Conductor type, at low temperatures, close to 4.2 K, due to a number of physical and geometrical effects.
Application of neural networks inversion in Magnetopneumography
Authors: Tomek Jiří , Platil Antonín , Ripka Pavel
Published: December 2018

To obtain unknown source distribution and magnetic moments of discrete magnetized ferromagnetic elementary volumes in our lung phantom we have chosen neural network inverse model. The simplified task was solved by regression multiple-layer perceptron network taught on data generated by multi-pole discrete forward model of the lungs. Magnetic fields corresponding to numerous possible sources were processed. The results are quite promising though more complex cases and especially in-vivo measurements would require much more measuring nodes over the patient/phantom to get enough data for reasonable inversion.
Flaw detection of underground pipeline using electrical potential method
Authors: Kojima Fumio
Published: December 2018

This paper presents a modeling approach to characterize adjacent cracks on underground gas pipe. Electrical potential method is used for capturing signals from surface cracks on the gas pipe. A three dimensional potential problem is considered for the inspection model. A defect parameter-to-output mapping is represented by means of finite element method in three dimensions. Computational methods for sizing and positioning of cracks are proposed based on our modeling approach.
Control implementation of a magnetic actuating ball and plate system
Authors: Lin Chin E. , Ker C.C.
Published: December 2018

A ball and plate system is constructed using magnetic suspension actuators on two axes for three degrees of freedom control. System characteristic in mathematical model for control is formulated using the backstepping control theory. According to the backstepping control design procedure, the proposed controller is fabricated on a single-chip microprocessor as control kernel and tested with supporting electronic circuits. Several scenarios of dynamic operation such as oscillatory stabilization and circular trajectory tracking are tested to verify the proposed system performance and capability.
Nonlinear forced vibration for electromechanical integrated toroidal drive
Authors: Xu Lizhong , Hao Xiuhong
Published: December 2018

In this paper, the equations of the electromagnetic forces between planet and worm or stator are presented. The electromagnetic forces are divided into static component and nonlinear ones, and then the nonlinear dynamic equations of the drive are given. By method of perturbation, nonlinear forced vibrations for the drive system are discussed. The changes of the vibrating magnitudes and vibrating frequency along with nonlinear parameter are given. A number of useful results are obtained. Results show: as nonlinear parameter increases, the natural frequency of the drive system change obviously, and the vibrating magnitudes change slightly; It is enough that only the first order nonlinear item is considered; the real nonlinear forced vibrations for the drive system are multi-mode coupled vibrations and for rotational and translational vibrations of the planet, or rotational vibration of the rotor, unstable periodic vibrations occur; change curves of the vibrating magnitudes along with exciting frequency bend toward the direction of the exciting frequency increase, and above changes are influenced by drive parameters obviously.
Analysis of a nano positioning actuator using a numerical method combined with a analytic method
Authors: Rho Jong-Seok , Kwak Sang-Yeop , Chung Tae-Kyung , Jung Hyun-Kyo
Published: December 2018

In this paper, we report on our study of a Nano Positioning Actuator(NPA), which uses an impact/inchworm mechanism. Many kinds of similar precise positioning actuators, which use the same working mechanism, are being and have been proposed by many researchers for several decades. But, the characteristic analysis and design method of the NPA has not been proposed yet. Also, the characteristic analysis and design methods of similar machines were approximate and ineffective.

Hence, we present in this paper an analysis methodology for the NPA using the 3D FEM combined with an analytic method, shedding light on the complex working mechanism, and taking all effective components into consideration for an exact and effective characteristic analysis of the NPA and similar machines. In this study, the mechanical system and the driving circuit of an NPA were prototyped. Finally, the effectiveness of an NPA, the reasonableness of a clarified complex working mechanism, and the adequacy of the proposed analysis method were validated by experimental data.
Numerical model for ultra thin electrical coils with magnetic fluid core
Authors: Popa N.C. , Siblini A. , Rousseau J.J. , Blanc-Mignon Marie-Françoise , Payet-Gervy Beatrice , Bayard B. , Nader C.
Published: December 2018

The paper investigates the numerical calculation of the electrical coils belonging to the inductive transducers with magnetic fluids for inclinations and aerodynamic measurements. One way to improve the construction of these transducers is to increase the electrical frequency for their coils. In this case, the thickness of the coils can be reduced by a large amount. The paper presents a numerical model for calculating the inductance of these ultra thin coils versus the level of the magnetic fluid core, the geometrical dimensions, and the magnetic properties of materials.
Numerical evaluation of potential integrals
Authors: Chen Duo , Shanker B. , McGough Robert J.
Published: December 2018

Analytical expressions are derived for fast calculations of 3D potential integrals. These fast calculation methods remove the singularities from potential integrals and thus achieve very fast convergence with a very small number of sample points. The simulation results show that for a given number of significant digits, the fast calculation method always converges much faster than the singularity cancellation method for the prism domain.
Trefftz discontinuous Galerkin methods for time-harmonic electromagnetic and ultrasound transmission problems
Authors: Badics Zsolt , Matsumoto Yoshihiro
Published: December 2018

An efficient strategy is described for the solution of time-harmonic electromagnetic and elastic wave problems. The strategy is based on the framework of the discontinuous Galerkin (DG) method, thereby using approximation bases that are locally conservative. Additionally, in the Trefftz DG method each approximation function satisfies the underlying partial differential equation in each finite element. The Trefftz DG method is similar to the ultra weak variational formulation (UWVF) but the local bases are constructed differently. Electromagnetic wave, eddy current and elastic wave problems are solved in order to analyze the performance of the method. The ultrasonic testing (UT) example is a two-dimensional elastic wave model of the Inconel welding area in reactor vessels.
Region of support calculations for a focused linear array of circular pistons
Authors: Shane Steven , Kelly James F. , McGough Robert J.
Published: December 2018

A geometric approach is developed to calculate the region of support for a focused linear array of circular pistons in a lossless medium. Equations are derived describing the boundaries of the region of support for a single piston. The model is expanded to examine the lossy case utilizing a Gaussian distribution to model attenuation in a viscous medium. These results are verified using the Fast Nearfield Method, and the numerical error is evaluated.
Passive wireless sensing using SWNT-based multifunctional thin film patches
Authors: Loh Kenneth J. , Lynch Jerome P. , Kotov Nicholas A.
Published: December 2018

This study presents a high-performance inductively coupled multifunctional carbon nanotube thin film sensor for structural monitoring applications. A versatile layer-by-layer self-assembly sensor fabrication technique is employed to encode different sensing mechanisms (e.g., strain and corrosion/pH) within one homogeneous thin film structure. Judicious selection of various polyelectrolyte species, along with the incorporation of carbon nanotubes, permits multifunctional sensing. Upon deposition of these thin films on miniature planar coil antennas to form a resonant circuit, a passive wireless sensor is realized. Unlike traditional cabled or wireless sensing systems, the proposed passive sensor does not require a constant power source, thereby rendering it ideally suited for embedment within structures.
Material characterization using a hand-held network analyzer
Authors: Stewart James , Havrilla Michael , Berrie Jeff , Kornbau Nathan , Stenholm Garrett , Albert Alan
Published: December 2018

In this paper a method employing a hand-held network analyzer is presented that allows in situ measurement of materials in environments unreachable by traditional network analyzers. Calculation of permittivity and permeability is accomplished using two reflection measurements from a waveguide probe. A comparison between the theoretical and experimentally measured reflection coefficients allows extraction of the material parameters using a root search algorithm. Parameter extraction results are presented and compared to those obtained from an HP8510 network analyzer employing the same waveguide probe and test materials.
Automatic measurement for local distribution of two-dimensional magnetic properties in a three-phase transformer model core
Authors: Kurakazu Atsushi , Todaka Takashi , Shimoji Hiroyasu , Enokizono Masato
Published: December 2018

This paper presents local distributions of measured two-dimensional magnetic properties in a three-phase transformer model core by using a new small V-H sensor. This new V-H sensor was developed to measure the local distributions of the magnetic flux density vector and magnetic field strength vector in magnetic steel sheets simultaneously. The local distribution of the iron loss by using the V-H sensor measured from the model core is shown and its accuracy for magnetic measurement of magnetic materials is examined.
Vibration properties of a coupled system of a magnetic fluid layer and a magnetic rubber membrane
Authors: Ido Yasushi , Yamada Tomoya , Shimada Kunio
Published: December 2018

Vibration properties of a coupled system of a magnetic fluid layer and a magnetic rubber membrane which is a silicon rubber membrane containing a magnetic compound fluid are investigated experimentally. Under alternating magnetic field, vibration of the coupled system has phase lag against the field, and the lag increases as the frequency becomes higher. At the range of low frequencies of the field, vibration of the system keeps nearly constant amplitude.
Miniature magnetostrictive linear actuator based on smooth impact drive mechanism
Authors: Ueno Toshiyuki , Higuchi Toshiro
Published: December 2018

This paper presents a miniature positioning device using Iron-Gallium alloy (Galfenol). Galfenol is a ductile magnetostrictive material with magnetostriction more than 200 ppm, Young's modulus of 70 GPa and high permeability. The actuator consists of a small pin of Galfenol, 1 mm diameter fabricated by ultra high precision cutting, winding coil, housing, and brass mover clamped on a frictional rod. The movement is based on the smooth impact drive mechanism, where the mover frictionally supported is moved step by step by inertia force with the rapid expansion and slow contract of the Galfenol pin. The miniature device driven less than 3 V was verified the velocity of 1 mm/s at driving frequency of 2 kHz with no-traveling limit, which will be applicable for positioning mechanism for mobile electronics.
Velocity and attenuation of ultrasonic propagation in magnetic fluids under a uniform magnetic field
Authors: Motozawa Masaaki , Sawada Tatsuo
Published: December 2018

Velocity and attenuation of ultrasonic propagation in magnetic fluids subjected to a magnetic field are examined experimentally. Measurements are taken while changing the magnetic field intensity and the angle between the magnetic field direction and the ultrasonic propagation direction. The ultrasonic propagation velocity and attenuation are dependent on the intensity and the elapsed time of the magnetic field. When the magnetic field is applied to magnetic fluid, magnetic particles form clustering structures and they effect on ultrasonic propagation in a magnetic fluid. Based on experimental results, the influence of the inner structure of the magnetic fluids on the properties of ultrasonic propagation is discussed.
Materials characterization using magnetic force microscopy
Authors: Suzuki Takayuki , Sasamoto Akira , Nishimura Yoshihiro , Teramoto Tokuo
Published: December 2018

The forward and inverse analyses of MFM images were performed to develop materials characterization technique using magnetic force microscopy. By the forward analysis of artificial magnetic recording media, the MFM images become focused with decreasing lift off height until 30 nm, both in a point dipole magnetic tip and in a finite size (50 nm) magnetic tip. However, in the case of the finite size magnetic tip, MFM images become degraded and especially duplicated at magnetic phase boundaries below 30 nm lift off height. By the inverse analysis of artificial magnetic recording media, the original magnetic charge was fully reconstructed using deconvolution and inverse Fourier transform techniques. By applying this technique to the experimental MFM image for ferromagnetic shape memory alloy, clear and noiseless martensite of variant structure was obtained from the MFM image.
Topology optimization with smoothness considerations
Authors: Campelo Felipe , Watanabe Kota , Igarashi Hajime
Published: December 2018

Topology optimization (TO) is a promising field for the design of industrial devices, since it can allow computational tools to develop creative solutions independently of initial topologies. However, the generation of smooth solutions, i.e., solutions that can be physically implemented, remains a challenge for most TO techniques available. In this paper, we discuss a set of operators that allow smoother topologies to be generated by an evolutionary topology optimization algorithm based on the artificial immune systems paradigm. The design of an electromagnetic device is used as a test case for the proposed methodology.
Optimisation of magnetostrictive bilayer sensors for medical applications
Authors: Kaniusas Eugenijus , Pfützner Helmut , Mehnen Lars , Kosel Jürgen , Hasenzagl Andreas
Published: December 2018

Magnetostrictive bilayer sensors have been successfully applied on the skin for the registration of various physiological quantities, ranging from the cardiorespiratory activity to the blood pressure changes. The application region was varied from the neck down to the calf. Thus an optimization of the sensor parameters becomes an increasingly important issue. Here the optimisation is considered with respect to curvature, bending momentum, and temperature of the bilayer. The results yield different requirements for different skin regions. In order to control the cross-sensitivity of the sensor, special sensor set-ups are introduced to reduce bending or thermal sensitivity, which is relevant for various medical areas.
Strain sensitivity in Tungsten-containing diamond-like carbon films for strain sensor applications
Authors: Takeno Takanori , Miki Hiroyuki , Takagi Toshiyuki
Published: December 2018

Tungsten-containing diamond-like carbon (W-DLC) film was investigated with the aim of strain sensor application. Three samples deposited under different methane flow rates were investigated. The strain dependence of normalized resistance has a linear dependence and the gauge factor has positive and negative values. The sensitivity and temperature coefficient of resistance(TCR) increase with an increase in the methane flow rate. However, from a practical point of view the sample with the lowest gauge factor is most appropriate for a stain sensor because it has the smallest TCR of the three samples.
Dynamic vibration analysis of axial flux PM synchronous machines using coupled-field analysis
Authors: Lee Byung-Jun , Jo Won-Young , Li Jian , Koo Dae-Hyun , Cho Yun-Hyun
Published: December 2018

This paper presents the dynamic vibration analysis of axial-flux permanent magnet synchronous machines(AFPMSMs). The major sources of vibration in electric machines such as motors and generators are the magnetic force and mechanical geometric shape. To decrease the mechanical vibration in AFPMSMs, we proposed an advanced design method considering the coupled-field analysis of the electromagnetic and mechanical problems encountered for both the rotor and stator. By the proposed method, the AFPMSM was analyzed, and characteristics such as the magnetic force, natural frequencies, mode shapes, and deformation were studied. This study has accomplished the dynamic vibration analysis of AFPMSMs.
Analysis of permanent magnet linear synchronous motor for advanced control
Authors: Zhu Yu-Wu , Kim Do-Sun , Moon Ji-Woo , Cho Yun-Hyun
Published: December 2018

A permanent magnet linear synchronous motor (PMLSM) is most suitable for fast, high-precision dynamic control systems. However, a significant drawback of PMLSM is the thrust ripple that deteriorates the performance of the drive system. This paper first presents a simple design for a PMLSM. Next, the thrust ripple is predicted by the finite element method (FEM) and it is fitted by a Fourier series using a curve fitting method. Finally, an advance field oriented control (FOC) method is used to compensate this thrust ripple by injecting an appropriate current. The effectiveness of this proposed thrust ripple suppression method is verified by the numerical results.
Image fusion based enhancement of eddy current nondestructive evaluation
Authors: Elshafiey Ibrahim , Alkanhal Majeed , Algarni Ayed
Published: December 2018

Recent advances in instrumentation and signal processing allow the acquisition of eddy current NDE signal in the form of c-san images. A technique is presented in this paper to enhance eddy current inspection based on multi-spectral, multi-temporal, and multi-resolution image fusion. The developed algorithm is motivated by human eye perception of colored objects. Mathematically it is based on the IHS transform, as well as the shift invariant wavelet analysis. Quality of resulting fusion images is evaluated based on statistical image quality metrics.
Automatic fuzzy based identification of flawed rivet in Magneto Optic Images
Authors: Cacciola Matteo , Deng Yiming , Morabito Francesco C. , Udpa Lalita , Udpa Satish , Versaci Mario
Published: December 2018

Magneto Optic Imaging is a relatively recent Non Destructive Evaluation technique, successfully used to evaluate the integrity of metallic parts in aging aircrafts. In this paper, the authors deal with the implementation of a suitable procedure able to recognize flawed rivets in Magneto Optic measurements. They have been carried out at the NDE Lab, Michigan State University, USA. Exploiting Fuzzy Subtractive Clustering in order to implement the classifier, our proposed approach retrieves a fast and robust applicative, useful for real-time applications. Preliminary results are really encouraging.
Diagnosis of damages of wings of rotor by electromagnetic field measurement
Authors: Demachi Kazuyuki , Rybalko Sergei , Yusa Noritaka
Published: December 2018

This paper proposes the method to detect and diagnose the defects of the rotating wings of turbines, pumps and motors by the measuring the change of the eddy currents comparing with those of no defects. The eddy current is induced in the conductor wings rotating in the static magnetic field and the magnetic field by the eddy current is measured by a pick-up coil. The magnetic field are obviously different between the wings with/without the defects. This method has the possibility of contribution to the earlier findings of the defects of the abnormality of the turbines, pumps and motors. Moreover, the time-series of the horizontal displacement of the rotating axis was measured by the laser displacement meter. To the axis, the external magnetic force was applied by a ring magnet to make the unstable state. The SSA (Singular Spectrum Analysis) [2] was applied to analyze the time-series of the displacement in the unstable state and it was shown that some of the SSA components are sensitive enough for the earlier detection of the transition to the unstable state.
Characterization and implementation of a GMR based probe for eddy current testing
Authors: Tamburrino A. , Ventre S. , Ferrigno L. , Udpa S.
Published: December 2018

The aim of this work is to describe an eddy current non-destructive testing system employing Giant Magnetoresistive (GMR) sensors. GMR sensors are solid state devices capable of measuring the magnetic flux density. The use of GMR sensors in the framework of eddy current testing is motivated by their intrinsically high sensitivity, large bandwidth and low cost. This paper is specifically focused on the development of a GMR based probe integrated into an eddy current testing system for detecting the presence of millimeters size cracks in highly conductive materials such as Aluminum.
Finite element analysis of coupled electromagnetic and thermal fields within a practical induction heating cooker
Authors: Chen Hung-Cheng , Huang Kuo-Hua
Published: December 2018

The analysis of an induction heating cooker is a complex process because induction heating is a combination of electromagnetic and heat transfer. In this paper, a coupled electromagnetic and thermal field analysis tool for education is proposed. The tool is based on the finite element method. A very simple and highly practical finite element computation procedure has also been developed, coded, implemented, and intensively used to simulate and analyze the above problem in a multiphysics environment. Particular attention is given to graphically visualizing the magnetic flux density of a specified induction heating cooker geometry. The corresponding induced eddy current density profile and temperature distribution are also presented. It gives a deeper insight into both electromagnetic and thermal phenomena for students. The forces on the plate caused by the eddy currents can also be studied and demonstrated in the numerical model. Combinations of geometric display and graphically parametric representations are effective for students to understand the designed induction heating cooker performance. The finite element simulation results of the transient temperature distribution are evaluated and compared with the experimental results. The accuracy of the simulation is demonstrated and appreciated. This finite element simulation and graphical visualization are therefore proposed as a valuable alternative prior to the actual final induction heating cooker design. Furthermore, in order to take care of the possible biological effects, some effort is expended to eliminate electromagnetic leakage emitted by the induction heating cooker.
Analysis of a ceramic plate thickness-twist mode piezoelectric transformer
Authors: Xu Limei , Wu Han , Fan Hui , Xiao Zhongmin , Yang Jiashi
Published: December 2018

We perform a theoretical analysis on a ceramic plate piezoelectric transformer operating with thickness-twist modes. Mindlin's first order theory of piezoelectric plates is employed. Forced vibration solution is obtained. Transforming ratio and vibration mode shapes are calculated. The effects of plate thickness, electrode dimension and inertia are examined. The results are useful to the understanding of the operating principle and the design optimization of the transformer.
The refined theory for a magnetoelastic body–I. plate problems
Authors: Gao Yang , Zhao Bao-Sheng
Published: December 2018

The problem of deducing two-dimensional theory from three-dimensional theory for a soft ferromagnetic elastic isotropic body is investigated. By using the general solution for the soft ferromagnetic elastic solids and Lur'e method, it is shown that the general deformation can be decomposed into two independent parts: the asymmetric deformations (plate problems) and the symmetric part (plane problems). A refined plate theory which takes into account the transverse shear deformation can now be explicitly established without employing assumptions. The exact equations and solutions for the plate with homogeneous boundary conditions are derived, and the equations can be decomposed into four governing differential equations. Moreover, the approximate equations and solutions for the plate under transverse loadings and magnetic field perturbations are derived directly from the refined plate theory. By omitting higher order terms and coupling effect, the refined plate theory can be degenerated into other well-known elastic and magnetoelastic theoretical models.
An analysis of ion channels in time-varying fields by the generalized Poisson-Nernst-Planck theory
Authors: Zhou Shu-Ang , Uesaka Mitsuru
Published: December 2018

An analysis is given in the article for the study of ion channel behavior in time-varying fields based on the generalized Poisson-Nernst-Planck theory, in which possible effects of the polarization relaxation and the effects of coupling among ion species, their diffusive fluxes and polarization in the mixture of ions can be evaluated. Analytical expressions for ion currents and voltages of the ion channel across a membrane are derived for the one-dimensional configuration both in time-independent steady state and in time-varying fields. While the results recover the classical Goldman-Hodgkin-Katz current and voltage equations in the time-independent steady state, it is shown that in time-varying fields, both the ionic current and the displacement current contribute to the total current in the ion channel, which depends not only on the equilibrium susceptibility of the mixture of the ions, but also on the dissipative polarization relaxation as well as the effect of coupling between the polarization and diffusive fluxes of the ions in the mixture. At the linear approximation, dissipative admittances that may characterize effectively the frequency responses of the ion channel in time-harmonic fields are also derived analytically for the one-dimensional case.
Green's functions for semi-infinite transversely isotropic electro-magneto-thermo-elastic material
Authors: Hou Peng-Fei , Yi Tao , Leung Andrew Y.T.
Published: December 2018

We use the compact harmonic general solutions of transversely isotropic electro-magneto-thermo-elastic material to construct the three-dimensional Green's function for a steady point heat source acted in the interior of a semi-infinite transversely isotropic electro-magneto-thermo-elastic material by five newly introduced harmonic functions. All components of coupled field are expressed in terms of elementary functions and are convenient to use. Numerical results are given graphically by contours.
Axially slotted antenna on a spheroid with an isorefractive coating
Authors: Hamid A.K. , Cooray F.R.
Published: December 2018

An algebraic solution is presented to the problem of radiation from an axisymmetric slot on a conducting prolate spheroid confocally coated with an isorefractive material, when the slot is excited by a delta gap source. The formulation of the problem is realized by expanding the electromagnetic field in each region in terms of spheroidal vector wave functions and a set of unknown expansion coefficients. Imposing the boundary conditions at the interface between the surface of the spheroid and the isorefractive coating, as well as that between the coating and the medium exterior to the coating leads to a set of simultaneous equations, the solution of which yields the unknown expansion coefficients. Numerical results are presented as normalized power patterns and radiation patterns for isorefractive materials, to show the effects of the coating on the radiation from the antenna.
Effects of electric field gradient on the propagation of short piezoelectric interface waves
Authors: Yang Zengtao , Yang Jiashi
Published: December 2018

We study anti-plane or shear horizontal piezoelectric waves propagating along the interface between two semi-infinite half-spaces of polarized ceramics with consideration of the effects of electric field gradient. An equation that determines the dispersion relations is obtained. Numerical solutions to the equation show that, different from the prediction from the linear theory of piezoelectricity, short interface waves become dispersive when electric field gradient is considered.
Application of wave concept iterative process to analyse microwave planar circuits
Authors: Tellache Mohamed , Lamhene Youcef , Haraoubia Brahim , Baudrand Henri
Published: December 2018

In the present work, the modeling of high frequencies planar circuits is proposed with an original iterative method based on the concept of waves. It consists in the development of simulation software based on an iterative method. The iterative method is developed from the fast modal transform on a two-dimensional fast Fourier transform algorithm. The method has been applied to the characterization and the modeling of patch antennas with notches in microstrip and coplanar technology and the quarter wavelength directive coupler. The obtained results are very satisfactory particularly in the reduction of the simulation time and the precision of the results in comparison with the literature.
Radio communication in circular tunnels
Authors: Abo-Seida Osama M.
Published: December 2018

The propagation of electromagnetic waves in a circular tunnel being studied, as far as his walls are made of concrete, its conductivity coefficient would be in the range 10 ^{-1} –10 ^{-2} mho/m. The cutoff frequency was also calculated and three different types of frequency range were characterized. Each of the frequency range is characterized, in turn, by certain propagation modes which differ in the cases of transverse electric modes (TE _{mn} – modes) and transverse magnetic modes (TM _{mn} – modes), (m, n = 0, 1). Besides, the attenuation constant was calculated at values larger and smaller than that of the cutoff frequency for both the transverse electric waves and transverse magnetic waves. Numerical results and graphes are also given for different values of m and n (m, n = 0 or 1) and a range of selected frequencies between 20–300 MHz.
Multiobjective design optimization of an excitation arrangement used in superconducting magnetic bearings
Authors: Di Barba P. , May H. , Mognaschi M.E. , Palka R. , Savini A.
Published: December 2018

The paper deals with the design optimization of high temperature superconducting magnetic bearings (SMB). The described algorithm allows a∼multiobjective optimal design with respect to the geometries of the gap oriented excitation arrangement as well as the superconducting bulks.
Integrated optimal design of a hybrid locomotive with multiobjective genetic algorithms
Authors: Akli C.R. , Sareni B. , Roboam X. , Jeunesse A.
Published: December 2018

In this paper, the Integrated Optimal Design (IOD) approach for energetic system design is discussed. IOD aims at concurrently optimizing the architecture, the element sizing and the energy management in an energetic system. IOD leads to complex optimization problems (typically mixed variable problems with several constraints and multiple objectives) which can be solved with direct optimization methods. We illustrate the interest of this approach through the design of a hybrid environmentally friendly locomotive moved by four DC motors supplied by a diesel engine generator in association with electric storage elements (batteries and ultracapacitors).
Optimal design of a traction system using Target Cascading
Authors: Kreuawan S. , Moussouni F. , Gillon F. , Brisset S. , Brochet P. , Nicod L.
Published: December 2018

In this paper, traction system design in carried out with a multilevel optimization technique called Target Cascading. This methodology is based on a hierarchical breaking down and allows solving a problem with multiple parallel optimizations. The large-scale system design problem is usually decomposed into several linked optimization subproblems according to project organization structure. Target Cascading gives a new approach to formulate and to solve the complex system design optimization problem in the electrical field. The problem formulation is more suitable to this kind of problem than conventional methods because it is closer to a work organisation of design engineers.
Solution of three dimensional inverse problem of magnetic induction tomography using Tikhonov regularization method
Authors: Ziolkowski M. , Gratkowski S. , Palka R.
Published: December 2018

Magnetic induction tomography, highly promising imaging technique for medical purposes, applies a magnetic field from an exciter to induce eddy currents in the object of low conductivity, and the magnetic field from these is then detected by a sensor. The induced eddy currents are proportional to the conductivity distribution. This paper deals with the solution of the fundamental inverse problem existing in magnetic induction tomography, which consists in the reconstruction of the eddy currents distribution basing on the magnetic field measurements. The problem has been solved by the Tikhonov regularization method. The choice of the regularization parameter and the accuracy of the proposed method have also been discussed.
Some methodological improvements of the contactless inductive flow tomography
Authors: Wondrak Thomas , Stefani Frank , Gundrum Thomas , Gerbeth Gunter
Published: December 2018

The goal of contactless inductive flow tomography (CIFT) is the velocity reconstruction in electrically conducting melts which are used in many metallurgical and crystal growth applications. In this paper, we discuss some recent methodological improvements of this method, in particular the automatic search for an optimum regularisation parameter and the amended treatment of the boundary integrals.
Effect of anisotropy in estimation of brain sources and conductivities via coupled EEG and MEG
Authors: Cutrupi V. , Ferraioli F. , Formisano A. , Martone R.
Published: December 2018

Purpose: This paper proposes an approach for the coupled EEG-MEG data analysis that takes into account the anisotropy of brain tissues and the different sensitivities of EEG and MEG measurements.

Design/methodology/approach: The study is carried out by using a combination of analytical and numerical methods. In particular, where available, closed solutions are used to evaluate the numerical errors, while FEM models are used where anisotropy and geometrical characteristics make analytical solutions not applicable.

Findings: The impact of tissues anisotropy on coupled EEG-MEG analysis has been assessed, and the effectiveness of an approach based on smart exploitation of different EEG and MEG sensitivity to improve sources reconstruction has been demonstrated numerically.

Research limitations/implications: The analysis has been carried out using a spherical head model, and on simulated data.

Practical implications: The proposed approach allows to improve the localization of equivalent sources for the description of cellular brain activity.

Originality/value: The properties of objective functions used in brain sources reconstruction from EEG and MEG has been investigated taking into account tissues anisotropy in the spherical symmetric case. In addition a formulation of the joint source and tissues tensor conductivity estimation by exploiting simultaneously bioelectric and biomagnetic measurements based on the complementary sensitivity of those measurements has been presented.
Dynamic analysis of the electric system for an electromechanical integrated toroidal drive
Authors: Xu Lizhong , Liu Xin
Published: December 2018

In this paper, the magnetic linkage equations for the toroidal worm coils are deduced. The voltage balance equation of the coils and the equation of the electromagnetic torque for the drive system are presented. The system equations of the drive system are given as well. The changes of the coil inductance along with the planet position angle for the drive system are investigated, the response of the current to exciting voltage is analyzed, and the influence of the system parameters on the start torque and the stable torque is discussed. The research is useful for design and optimum of the drive system.
Active control of piezothermoelastic FGM shells using integrated piezoelectric sensor/actuator layers
Authors: Zheng S.J. , Dai F. , Song Z.
Published: December 2018

An attempt on the static and dynamic control of functionally graded material (FGM) shells subjected to temperature gradient is carried out by using integrated piezoelectric sensor/actuator layers. Based on the assumed natural strain and enhanced assumed strain method, an EAS piezoelectric solid shell element is developed. The effects of constituent volume fraction and feedback control gain on the static and dynamic responses of the FGM shell system are demonstrated in detail.
Effects of bending stiffness and rotatory inertia in a mass-rod piezoelectric vibratory gyroscope
Authors: Chen Jiankang , Wang Wencai , Yang Zengtao , Wang Ji , Yang Jiashi
Published: December 2018

We perform a theoretical analysis on a vibratory gyroscope consisting of a concentrated mass connected to two orthogonal piezoelectric rods in extensional vibration. The analysis is more refined than a previous one in that the bending stiffness of the rods and the rotatory inertia of the mass are included. It is shown that when these effects are considered, the behavior of the gyroscope is affected in a fundamental way. The gyroscope has an output even when it is not rotating, and the output is sensitive to the rotatory inertia of the mass.
Modelling and analysis of piezoelectric smart structures for vibration and noise control
Authors: Gabbert U. , Lefèvre J. , Laugwitz F. , Nestorović T.
Published: December 2018

The paper presents an overall numerical approach for the simulation and design of smart lightweight structures in order to control vibration and noise. The design process requires an overall virtual computer model, which includes the passive mechanical structure, the acoustic fluid, the active materials, such as piezoelectric patch actuators glued to the structure, as well as the controller. Based on the finite element method such an overall model is presented in the paper. An acoustic box is used to verify the computational approach by comparing simulated and measured results.
Pyroelectric/electrocaloric energy scanvenging and cooling capabilities in ferroelectric materials
Authors: Guyomar D. , Sebald G.
Published: December 2018

In this paper, we investigated the Electrothermal conversion of ferroelectric materials. The key parameters for cooling and energy scavenging were identified: n the framework of pyroelectric energy harvesting, first results using SSD technique showed a magnification of the voltage by a factor of 2. We believed that the use of films could increase the power by a factor of 10–100. Currents works with PVDF films is being held in the laboratory. In the framework of electrocaloric refrigeration, we believe that ultrahigh efficiency cooling devices may be designed. However, the main limitation now is the maximal temperature of 1–2 K controllable by the electric field. Further work with small thicknesses (fibres, thin and thick films) will be interesting due to the very high possible electric fields.
Electroconductive cylindrical thin elastic shells carrying electric current and immersed in a magnetic field: Implications of the current-magnetic coupling on the shells' instability
Authors: Qin Zhanming , Hasanyan Davresh , Librescu Liviu
Published: December 2018

The dynamic behavior and instability of perfectly electroconductive circular cylindrical thin shells immersed in an applied magnetic field and simultaneously carrying electric current is modeled and investigated. It is assumed that the current and the applied magnetic field are parallel and aligned to the shell's longitudinal direction. Within the framework of the technical theory of thin shells, the 2-D equations of motion that capture the interaction between the shell and the electromagnetic field are derived. Having in view that the thin-walled structures carrying strong electric current are highly susceptible to buckling, by using the present model, the influence of the current-magnetic coupling on the shell buckling is specifically addressed.
Model of streamline upwinding and meshless method for electromagnetic field involving moving conductor
Authors: Yang Enhui , Wang Xinhong , Mo Jinqiu , Cao Jiayong , Wang Shigang
Published: December 2018

Streamline upwinding approach combining meshless method is proposed to model electromagnetic field involving moving component. And the detailed implementation of streamline upwinding meshless method is completed for A-φ-A formulation of electromagnetic field. Different numerical examples show that streamline upwinding approach can suppress effectively the numerical oscillation contained in meshless method solution of electromagnetic field involving moving component.
An artificial bee colony algorithm for inverse problems
Authors: Ho S.L. , Yang Shiyou
Published: December 2018

Based on the metaphor of the foraging mechanism of honey bee swarms as well as on available works, an artificial bee colony algorithm is proposed for solving difficult inverse electromagnetic problems. In the proposed algorithm, the entire searching process is divided into an intensification and a diversification phase. For intensification searches, some novel formulas are proposed for the employed bees and onlookers to carry out exploiting searches around specific memorized food sources; and scouts are used to generate new food sources to guarantee the diversity of the algorithm in diversification searches. Also, an age variable is introduced to measure the "exhausted" level of a food source and then decide when to abandon a memorized food source. Three numerical examples are reported to validate the robustness and to demonstrate the advantages of the proposed algorithm.
Dynamic analysis of switched reluctance motor with asymmetric half-bridge converter using surface current method (SCM)
Authors: Arehpanahi Mehdi , Milimonfared Jafar
Published: December 2018

In this paper dynamic analysis of switched reluctance motor (SRM) at startup, loading and remove loads based on surface current method (SCM) is proposed. Using combination of time stepping method and SCM in case of saturation, surface currents on the boundaries for dynamic analysis will be depending on time and rotor position. Simulation results and computation time are compared with Finite Element Method (FEM).
Development of a new voltage quality improving method for electromagnetic contactor
Authors: Chi Chieh-Tsung
Published: December 2018

This paper focuses on a novel control algorithm and its implementation method for providing voltage compensation to the coil of an AC electromagnetic contactor during voltage sags. Firstly, a new diagnosis algorithm is designed for correctly and timely detecting the voltage-sag event. When this new algorithm is embedded in the voltage compensation circuit and in series with the AC core of the contactor, the abnormal disengagement of the contactor contacts during voltage sag event could be eliminated through several experimental results. Another one designing point is that the dynamic position of armature can only be determined by a simple estimation method. In addition, the estimated position of armature and the applied voltage and coil current are taken as inputs by a single-chip based controller and provide the compensation voltage as output if voltage-sag event occurs. The above-mentioned new algorithm has been implemented in the laboratory.
A system for distal fixation of intramedullary nails
Authors: Martinez M. Rigoberto , Minor M. Arturo
Published: December 2018

This article describes the design and construction of an electronic device to assist orthopedic surgeons in the intramedullary nailing of long bones. The objective of the system is to reduce the cumulative radiation to which surgeons are exposed while performing the operation, as well as reduce the time required to complete the task. The system uses the magnetic flux of permanent magnets and electronic sensors to determine, without the need for a fluoroscope, the position of the distal hole in the rod. Tests show the system is feasible.
A rigorous analytical method for electro-magneto-elastic composites containing doubly periodic coated fibers under antiplane shear
Authors: Xu Y.L. , Xiao J.H. , Shen Y.Z.
Published: December 2018

The electro-magneto-elastic composites containing a doubly periodic parallelogrammic array of coated fibers are dealt with under antiplane shear coupled with inplane electro-magnetic loads, a rigorous analytical method is developed by using the generalized eigenstrain (an aggregation of eigenstrain, eigen-electric-field and eigen-magnetic-field) concept integrated with the doubly quasi-periodic Riemann boundary value problem theory. The expressions of electro-magneto-elastic fields in each phase of composites are obtained. A comparison with the finite element analysis (FEA) results demonstrates the accuracy of the proposed method. The effects of the coating with different thickness and stiffness on the stress concentration factor and electro-magneto-elastic effective moduli are discussed and a lot of interesting electro-magneto-elastic interaction phenomena are revealed, which are useful to estimate and optimize the performance of such elector-magneto-elastic composites. Also, the present method can provide benchmark results for other numerical and approximate methods.
Analysis of Rosen piezoelectric transformers with end masses
Authors: Yang Jiashi , Jiang Shunong , Hu Yuantai
Published: December 2018

We propose to use attached end masses to introduce more design parameters and possible improvement of the performance of Rosen piezoelectric transformers operating with extensional vibration of rods. A one-dimensional model developed in a previous paper is used for a theoretical analysis to verify the concept. Numerical results based on the theoretical analysis are presented, showing the effects of the end masses.
Coupled circuits model combined with deteministic and stochastic algorithms for the inductor design
Authors: Amrane Samia , El Hadi Latreche Mohamed , Feliachi Mouloud
Published: December 2018

In this paper, we present a model dedicated to the resolution of the inverse problem concerning the design and the dimensioning of an inductor which generates a desired magnetic field. The algorithms of optimization are combined with a semi analytical model which is based on the coupled circuit's theory. The latter makes it possible to predict the distribution of the currents density in the turns of the inductor and then to determine its electrical resistance and inductance. Therefore, it lends itself well to the optimization of the inductor parameters.

A comparative study between the use of a deterministic algorithm and another stochastic type of Simulated Annealing will be presented. The results obtained show that this approach is effective, precise and especially very fast for the optimization of the inductor parameters.