bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly uniform single-sided portable NMR sensor and its application in assessing the aging level of silicone rubber insulators
Authors: Xu Zheng , Meng Kaikai , Cheng Jiangyan
Published: December 2018

This study presents a high-performance single-sided portable nuclear magnetic resonance (NMR) sensor. The magnet array, which is composed of five identical cuboid permanent magnet blocks and two passive shimming sheets, generates a highly uniform B_{0} field in a 10× 10 mm ^{2} lateral area. Along the two orthogonal lines in this lateral area, the measured B_{0} strength variation is less than 338 ppm. Vertically, the measured B_{0} magnitude decreases from 144.387 mT to 130.603 mT, with a constant gradient of 4.6 T/m from 0.15 mm to 3.15 mm above the magnet surface. A planar radiofrequency coil is optimized according to the signal-to-noise ratio level of the coil. A one-dimensional profiling experiment on an oil film shows that a vertical resolution of approximately 1.7 μm can be achieved. As an application, the silicone rubber insulators are measured using the NMR sensor. Results demonstrate that the silicone rubber insulators with different service times can be distinguished through the transverse relaxation time T_{2} of the silicone rubber insulators.
Survey of a contact model and characteristic analysis method for a travelling wave ultrasonic motor
Authors: Ro Jong-Suk , Jung Sang-Yong , Lee Cheol-Gyun , Jung Hyun-Kyo
Published: December 2018

The important research area associated with the Ultra-Sonic Motor(USM) is the contact problem between the stator and the rotor. Because the USM operates by the friction force between the rotor and the stator, the contact problem of the USM have to be taken into account to analyze the motor performance accurately. Consequently, various types of the analysis methods have been proposed based on a contact model which describes the complex nonlinear contact condition of the USM. In this paper, diverse types of contact analysis methods for a Travelling Wave Ultra-Sonic Motor (TWUSM) are clearly condensed and precisely examined. The governing equations for the analysis of the TWUSM performance are derived through a precise investigation of the relationship between the contact condition and the motor performance in this paper. Furthermore, the motor performance is analyzed using contact models and the calculated data are compared with the experimental results.
Dynamic circuit model of a radial magnetic bearing with permanent magnet bias and laminated cores
Authors: Le Yun , Fang Jiancheng , Han Bangcheng , Zhang Yin
Published: December 2018

A hybrid radial magnetic bearing (HRMB) with permanent magnet creating bias flux is used to reduce the power consumption. Laminated cores are widely used in HRMB to reduce eddy currents. Nevertheless, when the frequencies of rotation and control currents are extremely high, eddy-current effects in laminated iron cores still have a significant influence on the behavior and performance of magnetic bearings. In order to predict performance and guide design of the HRMB system in high frequency, an analytical method based on equivalent circuit model whose parameters are frequency-dependent is used in this paper. The analytical results show that, the eddy currents induced due to rotor movement and dynamically changing control currents will result in considerable magnitude decrease and phase lag of bearing stiffness. Furthermore, the eddy current effect on HRMB can be reduced by increasing the air gap, decreasing the laminations thickness and decreasing the laminations conductivity. Finally, a prototype is designed and fabricated; the experimental results demonstrate the validity of the analysis.
Research of magnetic memory signal characteristics corresponding to early fatigue damage
Authors: Leng Jiancheng , Zhang Hui , Wang Lihua , Miao Xiujie , Xing Haiyan
Published: December 2018

A newly arisen technique named metal magnetic memory is deemed to have potentials in detecting early damage, whereas it is lack of systematic micro-mechanism research in early fatigue damage of ferromagnetic components. The microscopic fatigue experimental system including XH-500 metallograhpic microscope, DIG300 special digital camera and magnetic memory testing device, combined with the magnetic memory microscopic fatigue observation method is adopted, and the tension-tension fatigue experiment with specimens made of steel 45 are conducted. The evolution process of fatigue short-crack initiation and growth is observed dynamically from the microscopic scale, and the variation regularity of microscopic Vickers hardness during the fatigue procedure is also given. At the same time, the variation of the magnetic memory signal on the surface of the V-shaped notch with cyclic numbers is analyzed, and the magnetic signal curve distribution regularity corresponding to different crack lengths is investigated. The results show that the magnetic memory signals exhibit an abnormal nonlinear wave when the local plastic deformation or micro-damage occurs, providing a feasible detection method for early fatigue damage of ferromagnetic materials.
A novel design of low profile circularly polarized antenna with high gain and wideband characteristics
Authors: Li Xi , Zheng Xian-Bao , Yang Lin , Wang Shi-Wei
Published: December 2018

A novel design of low profile circularly polarized antenna with performances of high gain and broad bandwidths is presented in this paper. Through the method of connecting the radiating patch to the ground plane by the metal wall, the peak gain of the antenna can be achieved as high as 11.8 dBi. Furthermore, In order to improve the axial ratio (AR) and impedance bandwidths, broadband 90° phase-shifter is introduced as feeding network. Annular-ring structure acts as radiating patch instead of circular patch can further improve the AR bandwidths. The measured results show that the antenna possess an impedance (VSWR ⩽ 2) bandwidths of 23.3% ranging from 1.87 GHz to 2.36 GHz, and right-handed circular polarized (RHCP) axial ratio (AR ⩽ 3dB) bandwidths of 24.3% ranging from 1.84 GHz to 2.35 GHz relative to the center frequency of 2.1 GHz, which agree well with simulated results.
Design and comparison of a novel 3-DOF deflection type permanent magnet actuator
Authors: Li Zheng , Zhang Yue , Wang Xinxin , Wang Caisheng , Yan Caihong
Published: December 2018

This paper presents the design and analysis of electromagnetic field distribution and torque characteristics of a novel three degrees of freedom deflection type permanent magnet actuator based on 3D finite element method and comparison analysis. The spatial magnetic field model, torque calculation model and 3D finite element application are presented and developed. Based on the calculation results, some important structure parameters' effects on the electromagnetic field and torque characteristics are discussed in detail with improved design schemes. The results provide the primary theoretical guide for the configuration design, optimization and control research of three degrees of freedom deflection type actuators.
ANFIS model for determining resonant frequency of rectangular ring compact microstrip antennas
Authors: Akdagli Ali , Toktas Abdurrahim , Bicer Mustafa Berkan , Kayabasi Ahmet , Ustun Deniz , Kurt Kasim
Published: December 2018

In this work, a model constructed with the adaptive neuro – fuzzy inference system (ANFIS) for estimating the resonant frequency of rectangular ring compact microstrip antennas (RRCMAs) in UHF band is proposed. A total of 108 RRCMAs having different parameters related to the antenna dimensions and dielectric substrate were simulated with the help of electromagnetic packaged software IE3D™ based on method of moment (MoM) to generate the data pool for training and test processes of the ANFIS model. While 96 RRCMAs were employed for training, the remainders were used for test the ANFIS model. The resonant frequencies were computed with the average percentage errors (APE) as 0.014% and 0.666% for training and test, respectively. The accuracy of proposed model was successfully demonstrated by comparing with the results of a method over the simulated data previously published in the literature. Further to inspect the validity of the ANFIS model, a RRCMA operating at 2.44 GHz was designed and fabricated for this work, and the accurate results concerning the resonant frequency were achieved.
Experimental study of railgun aluminum armature electrical contact ablation
Authors: Peng Xiaoting , Zhan Zaiji , Li Zhixin
Published: December 2018

Because of strong current, friction and arcing, electrical contact ablation occurs in the transmitting process of electromagnetic railgun, which is also one key issue in application. In this paper, an experimental apparatus is designed to detect electromagnetic railgun armature contacts ablation. Energy dispersive X-ray, scanning electron microscopy, high-resolution camera and rogowski coil are used to measure mass loss, volume change, the ablation layer analysis, the element distribution on ablation layer section and the electrical contact analysis. Experimental results show that the input current and the contact pressure between electrodes are the major factors contributing to the ablation volume loss and mass loss. It is also showed that as a sliding electrode, the aluminum armature ablates more seriously during launch.
EMI analysis of PCB excited by external incident wave using a hybrid S-matrix
Authors: Tian Wen-Yan , Wu Ying-Chun , Li Ze-Min , Dong Zeng-Shou , Guo Yi-Na , Luo Ming
Published: December 2018

A hybrid S-matrix is proposed based on artificial neural network (ANN) and Baum-Liu-Tesche (BLT) equations to analyze the electromagnetic interference (EMI) effects on PCB with active and passive circuit components. Transmission line equations and Finite difference time domain (FDTD) method are employed to compute the excited fields and extract the port parameters for passive printed circuits. ANN method is used to predict the S-parameters for some active components. Then, the trained ANN model is combined with other S-parameters to compose a hybrid S-matrix for the characterization of the PCB. The resulting hybrid S-matrix and excited fields are subsequently exported to BLT equations to evaluate the responses. Examples are studied and the numerical results are compared with those obtained by experiment. The agreement is generally good that validates this method.
A comparison between the epoxy-bonded layer structure and shear-lag model in a thickness-shear mode circular cylindrical piezoelectric transformer
Authors: Li Peng , Jin Feng
Published: December 2018

The thickness-shear modes in a circular cylindrical piezoelectric transformer considering the effect of an epoxy-bonded layer are analyzed, and an exact solution is obtained from the equations of the linear theory of piezoelectricity. Systematic parametric studies are subsequently carried out to quantify the effects of the epoxy-bonded layer upon the transformer performance, including its thickness, elastic coefficient and mass density. It is demonstrated that whilst the thickness and elastic coefficient of the layer affect significantly the resonance frequencies, transforming ratio, power density, admittance and efficiency, and its mass density has negligible influence. On condition that the thickness of the epoxy layer is vanishingly small so that it degenerates into the solution by the classical shear-lag model. Upon comparing with the predictions obtained by employing the traditional shear-lag model, it is found that the interface viscous damping is absolutely due to the elastic coefficient of the epoxy layer, and the present structure model is found to be more accurate especially when the thickness of the epoxy layer can not be neglected.
Characterization of cracks using eddy current tomography
Authors: Sikora R. , Sikora J. , Pańczyk B.
Published: December 2018

Nuclear reactor coolant tubes are routinely inspected using eddy current methods. Classical methods rely on either human or automatic interpretation of impedance plane trajectories generated by differential eddy current probes to determine the condition of the tube. An alternative approach is to use a modified version of the Electrical Impedance Tomography (D.C. Barber and J. Sikora, 1995) (in this case called the Eddy Current Tomography) for the material coefficient imaging in a certain sub-region of the tubing. The problem can be defined as the inverse problem involving the estimation of the material coefficients (conductivity \gamma ) (S.-y. Hahn et al., 1995). In order to solve the inverse problem it is necessary to carry out the sensitivity analysis that provides the gradient of the objective function F . The main goal of this paper is to present the adjoint variable method, an efficient tool for gradient calculation.
Optimum selection of frequency for medical equipment using electrical impedance tomography
Authors: Sikora Ryszard , Zeńczak Michal
Published: December 2018

The paper presents the problems connected with the selection of frequency for medical equipment using Electrical Impedance Tomography (EIT). The paper considers the problem of electromagnetic compatibility (EMC) between the object under examination and the EIT device. The frequencies of biological signals most often do not exceed few tens of hertz. The problem of EIT system influence on human organism comprises influence of quite weak electric and magnetic fields on the living matters. In some systems may occur the thermal effect. Moreover the optimum selection of frequency has great influence on the resolution of images. The selection of frequency bases on the maximum of differences in the resistivity of the adjacent tissues. Analysis of the problems points at the range with bottom limit about 10 kHz and top limit about 100 kHz as the optimum range of frequency.
A new amorphous alloy for magnetoelastic waves applications Fe62.5Co6Ni7.5Zr6Cu1Nb2B15
Authors: Lanotte L. , Iannotti V. , Müller M.
Published: December 2018

On the basis of recent results a new composition for easy rapid quenching production of good magnetoelastic amorphous ribbons was selected. The production was successful and the experimental results in agreements with the predictions. The structural relaxation induced by annealing produces a very high improvement of the magnetoelastic response so that the new alloy results the most promising for magnetoelastic wave application in sensor devices. In particular the amplitude of resonant magnetoelastic wave results the highest still now obtained in an amorphous ribbon.
Optimal shape design of an iron-cored electromagnet: A further benchmark problem in magnetostatics
Authors: Di Barba P. , Savini A.
Published: December 2018

A new benchmark for inverse problems in magnetostatics is proposed; it deals with the optimal design of the pole profile of an iron-cored H-shaped electromagnet. The objective function, expressing the field uniformity in the air gap, is computed via the finite element method. The inverse problem is solved by synthetizing the distribution of the magnetic material in the design region; the optimization procedure relies on a stochastic method.
A comparison of the electrodynamics of metals under the action of large electric currents
Authors: Baginski Michael E. , Shaffer Edward C. , Thomas Keith A. , McGuirk Jeffrey S.
Published: December 2018

A numerical investigation of the behavior of electrically thin exploding foils is presented. This work examines the effect that non-linear material properties have on the electrodynamic behavior of three metallic bridgefoils (Al, Cu, Au) having identical geometries but different material compositions. Previous experimental work and simulations focused on copper bridgefoils electrically excited using the first quarter cycle of a 1200 A, 1.7 Mhz current source. This high power current pulse induced solid to vapor phase transitions over the entire foil surface in exploding foil experiments. Use of a finite element code (FEM) to determine the transient thermal and electrical effects in the pre-melt regime has been previously demonstrated for copper. The FEM code solves two non-linear partial differential equations which account for the thermal conductivity, latent heat of fusion, and specific heat(C _{\rm v} ) of the foil. The focus of this research is to contrast the simulated behavior of three metal foils (Al, Cu, Au) by examining corresponding plots of electrical and thermal signatures as the foils progress temporally to melt. The model predicts that the pattern of pre-melt behavior for all three foils is similar. The time to melt was found to be shortest for gold, followed by copper, and finally, aluminum ( T_m {\rm Au}< T_m {\rm Cu} < T_m{\rm Al} ).
On maximum likelihood identification of spatially-varying parameters in stochastic parabolic systems
Authors: Aihara Shin Ichi
Published: December 2018

The maximum likelihood estimation (M.L.E.) for spatially-varying parameters in stochastic parabolic systems is studied. The main result is to show the consistency property of the M.L.E. for unknown parameters by using the method of sieves, i.e., first the admissible class of unknown parameters is projected into a finite-dimensional space and next the convergence of the derived finite-dimensional M.L.E. to the infinite-dimensional M.L.E. is justified under some conditions. Finally numerical examples are presented.
Effective method to characterize magnetic stripes
Authors: Albrecht M. , Ahlers H. , Nendel U.
Published: December 2018

In this paper a simplified method for the characterization of magnetic media used as magnetic stripes on identification cards and tickets is described. It is based on standard measuring procedures but provides the advantage of less calibration work and a minimum set of measurements and calculations.
A method for the efficient determination of the remanent magnetization curve of magnetic stripes
Authors: Harcken H. , Albrecht M. , Ahlers H.
Published: December 2018

A method is presented which allows a system available for the measurement of the dynamic electromagnetic properties of magnetic stripes to be extended in such a way that the stripes' static properties can be determined from the remanent magnetization curve. The results of some check measurements show good correlation with the results of static measurement methods so far applied. The advantages and prerequisites, as well as the steps to be taken and the hardware required for the set-up will be described and the measurement sequence explained.
Micrograph and crystal structure of high magnetostrictive susceptibility of Fe-Pd thin films
Authors: Yabe Hiromasa , Oguri Kazuya , Uchida Haru-Hisa , Matsumura Yoshihito , Uchida Hirohisa , Nishi Yoshitake
Published: December 2018

The magnetostriction induced shape memory effect (MSME) was investigated in the Fe-Pd thin films prepared by magnetron sputtering. The reversible relationship was obtained between shape change and applied magnetic field from earth magnetic field to 0.2 kOe. The high magnetostrictive susceptibility were detected at low magnetic field below 0.2 kOe at room temperature. These were higher than that of Tb _{0.3} Dy _{0.7} Fe _2 thin film developed.
Effect of heat treatment on properties of Ni-Mn-Ga films prepared by a sputtering method
Authors: Ohtsuka Makoto , Itagaki Kimio
Published: December 2018

The effect of heat treatment on the properties of Ni-Mn-Ga films such as chemical composition, crystal structure, microstructure and transformation temperature were investigated with respect to various sputtering conditions. Ni-Mn-Ga films were deposited on a poly-vinyl alcohol substrate with a radio-frequency magnetron sputtering apparatus using Ni _{50} Mn _{25} Ga _{25} and Ni _{52} Mn _{24} Ga _{24} targets. After separating from the substrates, the films were annealed at temperatures between 873 and 1273 K for 3.6 ks. The chemical composition of the films depended on the sputtering power, but there was no dependence on the heat treatment temperature. Each deposited film had a columnar grain structure. After the heat treatment, the width of the columnar grains increased and then became indistinct with increasing heat treatment temperature. The martensitic transformation temperature increased with increasing nickel content of the films, while the Curie temperature decreased. The film heat-treated at 1073 K showed a two-way shape memory effect through the martensitic transformation and its reversion.
Development of artificial urethral valve with transcutaneous energy transformer
Authors: Tanaka M. , Goto H. , Namima T. , Matsuki H. , Orikasa S. , Tanahashi Y. , Chonan S.
Published: December 2018

This paper is concerned with the development of an artificial urethral valve for treating urinary incontinence, which is driven by shape memory alloy actuators. The latest valve has been modified by adding the SMA for the closing, which has the effect of preventing incorrect actions. Further, a compact, non-contact induction heating system using power transmission coils is introduced, which is improved by using an oscillation and amplifier circuit. It is found that the valve shows good opening and closing functions experimentally by using the urethrae of male dog through the induction-heating system.
Possibility of controlling the shape memory effect by magnetic field
Authors: Inoue Kazuko , Enami Kazuyuki , Igawa Masafumi , Yamaguchi Yasuo , Ohoyama Kenji , Morii Yukio , Matsuoka Yuki , Inoue Kanryu
Published: December 2018

We have made the Heusler-type Ni _2 MnGa-based alloys, Ni _{2.18} Mn _{0.82} Ga, Ni _{2.19} Mn _{0.81} Ga and Ni _2 Mn _{0.92} Ga _{1.08} , which have the martensitic transformation temperature coincident with the Curie temperature. The powder neutron diffraction measurements of these alloys were performed. The Rietveld analysis of the diffraction patterns showed that at least two crystal structures coexist in each martensitic phase. For Ni _{2.18} Mn _{0.82} Ga and Ni _{2.19} Mn _{0.81} Ga, the main structure is a monoclinic one with a six-layers shuffling and a small amount of orthorhombic structure distorted from the cubic Heusler one is included. For Ni _2 Mn _{0.92} Ga _{1.08} , the main structure is tetragonal whereas a small amount of other structures seem to be included. The neutron diffraction of Ni _{2.19} Mn _{0.81} Ga under magnetic field up to 5 T at the coincident transformation temperature of 350 K shows that the magnetic field causes the phase transformation from cubic phase to martensitic one. The result suggests the possibility of controlling the shape memory effect originating from the thermoelastic martensitic transformation, by applying the external magnetic field instead of changing the temperature.
Studies of various topologies of passive magnetic current limiter
Authors: Mukhopadhyay S.C. , Iwahara M. , Yamada S. , Dawson F.P.
Published: December 2018

Different topological configurations for a passive magnetic current limiter consisting of a permanent magnet and saturable core are discussed in this paper. The models for a series/parallel biasing mode, and a single/three phase supply system have been fabricated and the experiments have been carried out for the performance evaluation. Using tableau method, the transient performance of different models has been simulated. The feasibility of applying the current limiter for the protection of power semiconductor devices in moderately low voltage applications is investigated.
Analysis of electromagnetic scattering property of anisotropic materials
Authors: Juhui Yu , Yongming Li , Jian Huang
Published: December 2018

In this paper, the electromagnetic scattering property of a square tabular conductor coated with anisotropic material in three-dimension is studied via Finite-Difference Time-Domain (FDTD) method. From the results, one can find that if the parameters of the anisotropic material change, the backward scattered field will also change. And lower backward scattered field can be obtained by adjusting the parameters of coated anisotropic material.
An experimental study on the correlation of natural magnetization and mechanical damages in an austenitic stainless steel
Authors: Chen Zhenmao , Aoto Kazumi , Kato Shyoichi , Nagae Yuji , Miya Kenzo
Published: December 2018

In this paper, a passive nondestructive evaluation method is proposed for inspection of damage in an austenitic stainless steel of SUS304 type based on the measurement of the magnetic field caused by the damage-induced magnetization. The detectability of the proposed method is investigated by introducing mechanical damages with tensile/fatigue test and measuring the magnetic field with the flux-gate sensors. The experimental results show that the plastic or fatigue damage is possible to be recognized from the measured signals of the natural magnetic field, which verified the feasibility to apply the proposed technique to the damage inspection.
Theoretic means using space harmonic method for various reluctances analysis and end-effect of linear induction motor
Authors: Jung Sang-Yong , Jung Hyun-Kyo
Published: December 2018

Theoretic means using space harmonic method for Linear Induction Motor(LIM) analysis are suggested. The various reluctances usually approximated by adopting the current sheet are investigated thoroughly. Moreover, end-effect, the distinctive feature of LIM, is explained clearly by the proposed method.
Analytic methodology for slotless permanent magnet linear synchronous motor considering end-effect
Authors: Jung Sang-Yong , Jung Hyun-Kyo , Chun Jang-Sung
Published: December 2018

This paper is presented for suggesting the analytic methodology, Space Harmonic Method, for slotless Permanent Magnet Linear Synchronous Motor(PMLSM) implying the real physical aspect of structure. Especially, the details of the end-effect, a kind of fringing effect resulted from the moving magnet, can be investigated effectively by adopting the proposed method. Furthermore, a distinctive feature of EMF distribution closely concerned with end-effect will be overviewed theoretically.
Effect of magnetic field on a tuned liquid damper using a magnetic fluid
Authors: Ohira Yasuhiro , Houda Hiroshi , Sawada Tatsuo
Published: December 2018

The frequency response of a tuned liquid damper (TLD) which uses a magnetic fluid (called a "tuned magnetic fluid damper" (TMFD)) is investigated. A single-degree-of-freedom tuned mass damper (TMD) analogy is used to define the effective mass, stiffness and damping and these parameters are then estimated from experimental results. A numerical simulation is used to examine the TMFD and appropriate magnetic field conditions for effective damping are predicted. In particular, the performance of the TMFD was improved by switching the applied magnetic field at a point near the resonant frequency of the undamped structure.
Numerical study on sticking of paper in electrostatic transfer process for electrophotography
Authors: Nakayama Nobuyuki , Yimei Yu
Published: December 2018

A numerical study was carried out on the electrostatic sticking of a charged paper to photoreceptor in electrostatic transfer process for electrophotography. Numerical procedures to predict sticking of the paper were presented which consists of (1) determination of initial angle of the paper,(2) estimation of electric field intensity, (3) estimation of charge on paper created by Paschen's air breakdown, (4) estimation of electrostatic force acting on the paper and (5) calculation of deformation of paper. Deformation of the charged paper in electric field was numerically simulated according to the procedures and the dependencies of paper sticking on photoreceptor size and initial angle of paper were quantitatively clarified. It is clarified that the smaller and softer photoreceptor improves sticking of paper.
Numerical simulation of biased roller transfer by one-dimensional quasi-steady electric field analysis
Authors: Ito Tomoyuki , Kawamoto Hiroyuki
Published: December 2018

A stable and accurate numerical simulation technique is proposed to investigate performance of the transfer system using a biased transfer roller(BTR) in electrophotography. A one-dimensional layer-structured model was used to calculate distribution of electric field and current under air discharge. Concentration of generated ozone was also calculated. As results of calculations for a typical black and white laser printer, it was shown that (1) a transfer system using a semi-conductive BTR under constant current operation was robust against variation in resistance of media, and (2) concentration of ozone in the BTR system was two orders lower than that in the system using a conventional corona device.
Vibration of exposure control system in security camera
Authors: Itoh Yoshiaki , Nagao Tatsuaki , Ozawa Toshifumi , Iwai Hiroyuki
Published: December 2018

In security camera, the exposure control system, called Iris meter, is widely applied to provide the optimal aperture of the lens for brightness. Sometimes, the unexpected vibration of the exposure control system is observed when the lens aperture is in the transient state of opening and closing. Such the vibration may not only lead the system status to the abnormal condition, but also play an important role in the long-term reliability of the system. The purpose of this paper is to examine the vibration of the exposure control system in security camera. First, some experiments are conducted to observe the dynamic properties of the system at the normal and abnormal condition. Second, theoretical discussion is made to give some information on the excitation mechanism of the vibration.
Horizontal noncontact positioning control for a magnetic levitation plate
Authors: Sekihara Takanori , Oshinoya Yasuo , Ishibashi Kazuhisa
Published: December 2018

When sheet steel travels at high speed in a processing facility, rollers are usually used as supporters. However, when rollers are used, deterioration caused by cracking is possible. The authors have proposed a magnetic levitation control system for sheet steel and confirmed the feasibility by an experiment on digital control. However, there is no horizontal restraining force in transport in the case of using only levitation control. Therefore, we proposed to install electromagnets in order to control the horizontal position. For the basic examinations, the sheet steel plate(length 800 mm, width 600 mm, thickness 0.3 mm) was reinforced by light carbon pipes in this study. To verify the usefulness of the proposed noncontact positioning control system of sheet steel, a digital control experiment was performed on transport. As a result, good positioning control performance for the levitated steel plate was obtained.
Tracking control of a two-stage servo head arm for a hard disk drive
Authors: Murai Masanori , Tani Junji , Qiu Jinhao
Published: December 2018

This paper describes a new type of two stage servo head arm for magnetic disk drives. Four PZT actuators were bonded to the stainless steel head arm. The PZT actuators were used for accurate follow-up of the track and also vibration control of the head arm. The PID control method was used in the design of controllers for vibration control and tracking follow-up control of the arm. The characteristics of a prototype of the servo system were measured and its effectiveness was verified by experiment.
Repulsive magnetic bearing stabilized by the motion control of magnets with a piezoelectric actuator
Authors: Mizuno Takeshi , Aizawa Mitsunori
Published: December 2018

A magnetic bearing system using forces of repulsion between permanent magnets was developed. In the developed magnetic bearing, the radial motions of the rotor are passively supported by repulsive forces. The motion in the axial direction, which is inherently unstable, is stabilized by using the motion control of the permanent magnets for passive radial suspension with a piezoelectric actuator. The developed magnetic bearing suspended a rotor without any mechanical contact. The characteristics of the suspension system were studied both theoretically and experimentally.
Computer simulation of magnetic levitation of thin steel plate
Authors: Marunaga Kazuo , Oshinoya Yasuo , Ishibashi Kazuhisa
Published: December 2018

This paper describes how to simulate magnetic levitation of a thin steel plate by using electromagnets. Since the levitation system is essentially unstable, the steel plate is levitated by controlling the attractive force produced by the electromagnets with feedback signals: the displacement and velocity of the steel plate and the current of the electromagnet. The motion equation of the steel plate is solved by the finite difference method. The attractive magnetic force by electromagnets is obtained by using the finite element method.
Antenna stabilizing control system with strapdown 2 axis azimuth/elevation method
Authors: Murakoshi Takao
Published: December 2018

A two-axis antenna-stabilizing control device which does not need a level sensor has been developed. The control incorporates a zero-servo method which zeros two gyro outputs by rotating an antenna with both an azimuth motor and an elevation-servo motor. In experiments using a Scorsby Table, pointing errors of less than a few degrees have been confirmed.
A study on the vibration analysis of a maglev vehicle -- A theoretical investigation of the effect of magnetic damping on a vibration control system
Authors: Watanabe Ken , Ohta Yasuhiro , Nagai Masao , Kamada Takayoshi
Published: December 2018

The superconducting Maglev system is conceptualized as the next generation high-speed public transportation system. For practical use, it is important to improve the ride comfort particularly in high-speed running. The Maglev vehicle is composed of lightweight car bodies and bogies which are mounted with SCMs (superconducting magnets), on-board refrigerating system, etc. The vibration isolation performance is lower than in conventional railways, since the mass ratio of sprung mass to un-sprung mass in the Maglev vehicle is lower than in the typical railway car. In this magnetically levitated system, the passive electromagnetic damping between the SCMs and ground coils is very small. Therefore, it is important to add active electromagnetic damping to the primary suspension between the SCMs and ground coils, and to adjust the secondary suspension between the car body and bogie.

This paper examines lateral and rolling vibration control of the Maglev vehicle using LQ (linear quadratic) control theory. Moreover, the estimated electromagnetic damping, which interacts between the SCMs and the guideway, is also considered in the model to improve the ride comfort.
A micromagnetic analysis of the Preisach model hypotheses on magnetic patterned media
Authors: Stancu Alexandru , Stoleriu Laurentiu , Cerchez Mihai
Published: December 2018

The interactions in particulate ferromagnetic media are generally described by magnetostatic interactions and exchange interactions. The Preisach type models describe the interactions by the use of an interaction distribution and a mean interaction field. It is usually considered that the mean interaction field is determined by the exchange interactions in the system, while the statistical interactions are determined by the magnetostatic interactions. This paper presents a micromagnetic analysis of the hypotheses used in the Preisach models to describe the magnetic particulate system.
Temperature characteristics of a new magneto-optical current transformer
Authors: Didosyan Yuri S. , Hauser Hans , Toriser Walter
Published: December 2018

In contrast to existing current transformers utilizing the Faraday rotation of light polarization, the principle of operation of the new sensor is based on the direct registration of the domain wall positions in an orthoferrite, a transparent ferromagnet. The results of the measurements are not affected directly by temperature changes of Faraday rotation, birefringence, fluctuations of the incident light beam, polarization distortions in fibers, etc. The amplitude of domain wall motion remains constant in a wide range of driving magnetic field frequencies from dc to hundreds kHz. With the further growth of the frequency the amplitude decreases in two times at 5∼MHz. In the temperature range from 20°C to 130°C the domain wall mobility and the bandwidth decrease in about three times.
Differential motion restraint coupling using magnetorheological fluid
Authors: Nagaya Kosuke , Tont Feng-Ying , Murakami Iwanori , Tai Norio
Published: December 2018

A differential motion restraint coupling is presented. In order to have strong torque, multi friction plates are installed in the friction unit of the device that involves magnetorheological fluid. Two permanent magnets lie on both sides of the friction unit. Hence, magnetic fluxes freeze the magnetorheological fluid. The friction discs have a number of slits in the radial direction, which generate torque due to shear forces between the frozen fluid and the slits. A design method has been presented for the device. To validate the present design formulae, experimental tests have been carried out. Calculated results are in good agreement with the experimental ones.
An iron loss calculation method for motor driven by PWM inverter power supply
Authors: Ohto Motomichi , Ishikawa Koji , Nose Yukio
Published: December 2018

An application of Finite Element Method for iron loss calculation is proposed. The motor iron loss is predicted by taking into account current ripple caused by PWM inverter power supply. This paper describes simulation method about iron loss under inverter drive system. In this method, drive system simulation is used to obtain the motor current waveform. The skin effect in the laminated core is considered by using results of two-dimensional magnetic field analysis. The method is applied to an interior permanent motor and shows the result of iron loss distribution in the motor.
Magnetic field standards -- tracing to the maintained units
Authors: Weyand Kurt
Published: December 2018

The present state of realization, maintenance and dissemination the quantity "magnetic flux density" in SI units is discussed. Different measuring methods that are in use for the calibration of field coils and permanent or electromagnetic systems in the flux density range from the order of the Earth's magnetic field up to some Tesla are compared with respect to their uncertainties. Special attention is given to systems based on the gyromagnetic ratio of protons as a fundamental constant.
Magnetic hysteresis modelling for vector magnetic property
Authors: Enokizono Masato
Published: December 2018

This paper presents a numerical modeling of vector (two-dimensional) magnetic properties considering hysteresis of silicon steel sheets. We define the magnetic reluctivity tensor newly and calculate it from the measurement data obtained by two-dimensional magnetic measurement. Our new modelings, which are "E&S Model" and "E&S2 Model", can be introduced into a finite element formulation for magnetic field analysis and can get the distribution of the magnetic field strength H-vector and the magnetic flux density B-vector.
Radial electric field control by electron injection in tohoku university heliac
Authors: Kitajima Sumio , Nakanishi Shigeyuki , Hashizume Hidetoshi
Published: December 2018

In this paper, we present experimental results of improvement for plasma confinement by controlling electric field with electron injection [1]. In order to generate the negative radial field, we inserted a hot cathode into the plasma and then biased negative voltage. We observed the plasma parameter changes after the hot cathode biasing: the increase of line density, the fluctuation suppression, the negative radial electric field formation, the plasma rotation, and the increase of the energy confinement time. These results suggest that the improvement of plasma confinement by the formation of negative radial electric field is achieved.
A large scale computation of 3-D eddy current problems
Authors: Kanayama Hiroshi , Tagami Daisuke , Matsumoto Satoshi
Published: December 2018

A large scale computation of three-dimensional eddy current problems is considered. Some techniques are introduced to compute large scale problems; their numbers of degrees of freedom are almost one million. A transformer model is considered as a numerical example.
Topology optimization of switched reluctance motor using mutual energy method
Authors: Byun Jin-kyu , Hahn Song-yop
Published: December 2018

In this paper, the rotor part of the SRM (switched reluctance motor) is designed by topology optimization method. The objective function is the desired system energy profile considering the rotation angle of the rotor. The topology optimization method can design the optimal shape and topology of SRM rotor without any prior knowledge of the basic rotor layout. The density method is used to establish the relationship between the design variables and material properties, and mutual energy method is used to calculate the design sensitivity.
3-D nonlinear eddy current analysis of factors affecting the evaluation of alternating flux leakage testing
Authors: Gotoh Yuji , Takahashi Norio
Published: December 2018

The signal of an alternating magnetic flux leakage testing is affected by several factors, such as the buried length from surface, depth of crack. In this paper, the effects of those factors on the flux distribution near a search coil are examined using 3-D nonlinear FEM. It is shown that the leakage flux is produced by the saturation of steel near the surface, if the distance from the surface to a crack is small.
A new anisotropic correction to the formula of Force and Torque on materials
Authors: Fujioka Takushi
Published: December 2018

When Electromagnetic fields of Devices are analyzed using anisotropy, in some cases, Forces and Torques should be calculated by the Maxwell's Stress Tensor Method. Then a new anisotropic correction to the Forces and Torques in their cases is introduced and calculated.
Performance analysis of permanent magnet generators by adaptive mode
Authors: Sobhi-Najafabadi Bijan , Göl Özdemir , Nafalski Andrew
Published: December 2018

Simple impedance models are routinely used in the design of permanent magnet generators. Unfortunately, this invariably results in poor prediction accuracy, particularly because saturation is not taken into account. This paper presents a method, which helps improve prediction accuracy by using field models as an adjunct to adjust the model parameters to the prevailing flux conditions in an adaptive mode.
Efficiency properties of adaptive mesh generation
Authors: Jänicke Lutz , Kost Arnulf
Published: December 2018

One of the major advantages of adaptive mesh generation is the optimum fitting of the mesh to the problem, leading to good memory efficiency. By suitably choosing the refinement parameters, the adaptive mesh generation is also time efficient. As the best refinement parameters depend on the problem to be solved and can also change during the adaptive solution process, they must be chosen dynamically. The choice is based on the error distribution, that is available from the local error estimation. Therefore no additional computational cost arises due to the dynamic parameter setting.
Force evaluation formula for integral methods of magnetic field computation
Authors: Hantila F. , Cranganu-Cretu B. , Preda G. , Miya K.
Published: December 2018

The aim is to report a very efficient approach to force calculation on ferromagnetic, rigid, movable parts of electromechanical systems. The constitutive relationships of the movable parts are nonlinear. Proof of the formula is based on the virtual work method for the co-energy of the system.
Modeling acoustic resonance in high-pressure discharge lamp arc chambers
Authors: Vágvölgyi Attila , Böröczki Ágoston , Gyimóthy Szabolcs , Sebestyén Imre
Published: December 2018

A numerical method was developed for modeling acoustic standing waves emerging in high-pressure discharge lamps. The applied model takes the inhomogeneous distribution of propagation velocity into account, which is caused by the temperature profile. Arc physics was not considered. Software was implemented based on the finite element method. In addition to the sole computation of waves in some practical arrangements, also the validity of the applied model was investigated.
Advanced electromagnetic field analysis for high quality beams
Authors: Weiland Thomas , Schuhmann Rolf
Published: December 2018

The quality of particle beams depends strongly on the quality of the accelerator. The major components of particle accelerators are beam optics elements such as quadrupole magnets, bending magnets and accelerating structures such as RF-cavities. The numerical field analysis of magnetic elements is well advanced and has become a standard tool in virtually any accelerator design. In this area there is only little progress to report as only in very specialized areas remains some need for new research. This is however not the case for the design procedures of accelerating structures. With the ever increasing demands for higher energy and very high quality beams the demands for electromagnetic design tools is drastically increasing. In this paper we focus on the latest developments in the area of high precision field computation and discuss new developments for the analysis of parasitic trapped modes.
Analysis of the heat load of thin metal foil during electron beam scanning
Authors: Drabik A. , Drabik W. , Rabinski M.
Published: December 2018

The thermal loading of thin metal foils used as extraction windows in high current electron accelerators is one of the most important processes which should be analysed during the design of such devices. Heat loads at metal surface are also of special interest in many other plasma applications.

The distribution of heat loads at the surface of thin metal foil is evaluated from the energy absorption in the foil and forced cooling with air flow. Time dependence of temperature distribution at the foil surface is calculated from the two-dimensional heat conduction equation. The simplified heat transient analysis is also given to determine the influence of scanning frequencies, electron beam size and shape ,shape of current impulses in scanning coils, energy loss in foil, the beam current and air cooling coefficient on time evolution of temperature for an arbitrary fixed point at the foil in first period of electron beam scanning.
Computation of higher order modes in TESLA structures
Authors: van Rienen Ursula , Glock Hans-Walter , Hecht Dirk , Rothemund Karsten
Published: December 2018

This paper presents results on the computation of Higher Order Modes(shortly HOMs) in the designs for the accelerating structures which have already been built in into the TESLA [1] Test Facility (TTF) or are presently being studied as final design for the TESLA collider.

Depending on the complexity of the studied arrangement different computational strategies are followed: 1. the use of commercial software packages like MAFIA [2] or CST Microwave Studio (MWS) [2] on workstations, and 2. a recently implemented tool for Coupled S-Parameter Calculation (CSC) which easily allows to calculate the scattering properties of rf-sections connected to each other with arbitrary topology or to determine eigenmodes of resonating structures.
High energy laser wakefield acceleration
Authors: Kotaki Hideyuki , Kando Masaki , Hosokai Tomonao , Kondo Shuji , Masuda Shinichi , Kanazawa Shuhei , Yokoyama Takashi , Matoba Toru , Nakajima Kazuhisa
Published: December 2018

Laser wakefield acceleration (LWFA) experiment using 100TW laser is planned at JAERI-Kansai. High quality short pulse electron beams and the precise electron-laser synchronization are necessary to accelerate the electron beam by the laser. A microtron with a photocathode rf-gun was developed as a high quality electron injector. The quantum efficiency(QE) of the photocathode was measured to be 2 × 10^{-5} . Emittance and a pulse width of the electron beams were 6π mm-mrad and 10ps, respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, the inverse free electron laser (IFEL) is planed. A gas jet was set up and a density of the gas was measured by Mach-Zehnder interferometer. In order to overcome a short acceleration length of the LWFA, the Z-pinch plasma waveguide has been developed for 1 GeV laser wakefield acceleration.