bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparative study of Loney’s solenoid by different techniques of global optimization
Authors: Borghi C.A. , Fabbri M. , Di Barba P. , Savini A.
Published: December 2018

The optimal shape design of Loney’s solenoid is carried out by different techniques of global optimization. The underlying inverse problem, which is numerically ill-conditioned with a gorge behavior, shows an outstanding potential as benchmark for magnetostatic inverse problems. In the paper four minimization methods have been compared: two of them are deterministic (Simplex and Quasi-Newton methods), two are stochastic (Evolution Strategy (1+1) formulation and Filled Function method combined with the Evolution Strategy method). The results have been discussed and compared.
Vibration of a hemispherical shell gyro excited by an electrostatic field
Authors: Chou Chan-Shin , Chang Chia-Ou , Hwang Jeng-Jye
Published: December 2018

In this paper the stability and precession phenomenon of the modal pattern of a rotating hemispherical shell gyro excited parametrically by electrostatic forces is investigated. Nonlinear modal equations of the rotating shell under small strain and moderate rotation are derived by following Niordson’s thin shell theory. The method of multiple time scales is used to determine quantitatively the vibration displacement of the shell from which the precession rate of the modal vibration pattern can be extracted. Floquet theory is employed to study the stability of the analytical solution. Numerical simulation verifies the analytical results.
A new technique to calculate the electrostatic Coulomb force on a conductor coated with a lossless dielectric
Authors: Inan Aziz S. , Osterberg Peter M.
Published: December 2018

In this article, the authors apply a new technique based on expressing the Coulomb force in terms of a special singularity integral to calculate the electrostatic force exerted on a conductor coated with a lossless dielectric. Specifically, the example of the calculation of the electrostatic Coulomb force on a lossless dielectric slab attached to the lower plate of a parallel-plate capacitor is considered.
The model simulating the magnetic properties of composite polymers
Authors: Sláma J. , Krivošík P. , Dosoudil R. , Vicen R. , Grusková A. , Olah V. , Hudec I. , Kováčiková S.
Published: December 2018

The magnetic properties and frequency spectra were studied in magnetic composites with the MnZn powder filler in polymer matrix. The frequency response of permeability, power loss and reactive power per frequency components were measured and compared with the computed data. For this purpose the model taking into account particle morphology in the selected frequency spectrum was proposed. The frequency responses of permeability components have the adequate frequency dependencies of powers per frequency for the sinusoidal waveform of applied magnetic field.
Millimeter-wave semiconductor two-port network at 77K
Authors: Sheikh Sharif Iqbal
Published: December 2018

The gyromagnetic properties of magnetized ferrites are widely used in many novel rf and microwave devices. According to the Drude model, similar principles should also be applicable to magnetized semiconductors due to its gyroelectric properties. In this study, an axially magnetized semiconductor resonator is characterized in terms of bias field and signal frequency. The resonance and loss regions are identified at 77 K. The affect of changing material and geometrical properties of the resonator on the splitting and tuning behavior of normal modes are illustrated. Green's Function approach is used to derive the S-parameters of a two port semiconductor network. The network response and the material properties can be used to calibrate the semiconductor material before measuring the millimeter-wave properties of the resonator. This theoretical analysis may prove to be vital in realizing miniaturized and broadband semiconductor junction circulators and filters for high- T_c superconductive circuits.
Scalar Hertz potentials for nonhomogeneous uniaxial dielectric -- magnetic mediums
Authors: Weiglhofer Werner S.
Published: December 2018

The scalar Hertz potential technique is applied to the field analysis in uniaxial dielectric -- magnetic mediums. These mediums may be either homogeneous or nonhomogeneous (with a nonhomogeneity of a restricted form). It is shown that the complete electromagnetic field in a uniaxial dielectric -- magnetic medium can be derived from two scalar Hertz potentials(plus, for certain types of problems, a small number of source -- specific auxiliary functions). The corresponding scalar Green functions are explicitly given for the homogenous case and applications for radiation and propagation problems are presented.
Homogenization techniques for linear dielectric random composite materials in stationary conditions
Authors: Luciano Raimondo , Tamburrino Antonello
Published: December 2018

In this paper, homogenized dielectric constitutive equations for heterogeneous materials characterized by a random arrangement of the inclusions are obtained. The homogenization problem is formulated by using the Hashin and Shtrikman variational principle and by considering macroscopic charge density. The solution of the homogenization problem is obtained both in the Fourier and in the space domain. Explicit expressions of homogenized constitutive equations are presented for statistically homogeneous two-phase composites in terms of the two point correlation functions of the inclusions. These functions are deduced for a special class of heterogeneous materials reinforced by square or rectangular fibres whose arrangement is generated from the probability density function (p.d.f.) of the centres of the inclusions. At this aim, an efficient procedure to obtain the two-point correlation functions from the p.d.f. of the centres is proposed. Finally, several examples of overall constitutive equations are developed both for periodic and for random composites and comparisons with exact results for laminates are presented.
Dynamic mode-III interfacial crack in ferroelectric materials
Authors: Shen Shengping , Kuang Zhen-Bang , Nishioka Toshihisa
Published: December 2018

This work is concerned with the analytical characterization of the electromechanical nonlinear effects on the fields surrounding the tip of an interface crack of Yoffe type between ferroelectric-plastic bimaterials. A strip electric saturation and mechanical yielding model is developed for a mode III dynamic interfacial crack with electrical polarization reaching a saturation limit and shear stress reaching a yield stress along a line segment in front of the crack. The electrical saturation zone and mechanical yielding zone may have different length scales depending on loading conditions. The results reveal insight into the structure of stress and electric displacement fields for different load conditions. The energy release rate and COD(crack-tip opening displacement) are also be obtained. It is also shown that the smaller nonlinear zone (mechanical yielding or electric saturation) size is related with the velocity v of the interfacial Yoffe crack. COD, COP (crack-tip opening potential) and the energy release rate J_a(v) all increase monotonically with increasing v .
The effect of non-uniform magnetization of permanent magnets on the performance of a repulsive type magnetic bearing system
Authors: Ohji T. , Kano M. , Mukhopadhyay S.C. , Iwahara M. , Yamada S.
Published: December 2018

A permanent magnet bearing (MB) system utilizing the repulsive forces operating between the stator and rotor permanent magnet for levitation and radial control has been fabricated in our laboratory. The consistency of the permanent magnet magnetization effects the continuous steady-state and dynamic performance of the system. Since both the magnets are repelling each other, there will be demagnetization of the magnetization of the permanent magnet. Due to demagnetization or ageing or manufacturing asymmetry, the field distribution may not be uniform along the periphery of the magnet. In this paper the effect of this magnetization non-uniformity on the performances of the bearing system has been studied.
Characterization of phase transformations, long range order and thermal properties of Ni_{2}MnGa alloys
Authors: Hosoda Hideki , Sugimoto Tsuyoshi , Ohkubo Kenji , Miura Seiji , Mohri Tetsuo , Miyazaki Shuichi
Published: December 2018

Martensitic and magnetic transformation temperatures were investigated for Ni _2 MnGa alloys as a function of the degree of long-range order (LRO) associated with L2 _1 structure. The degree of order was changed by changing the heat treatment temperature. Besides, thermal properties such as thermal expansion (CTE), specific heat( C_P ) and thermal conductivity ( \lambda ) were measured up to 1273 K. It was found that with increasing the heat treatment temperature, the degree of second neighbor ordering lowered, but that the degree of first neighbor ordering did not show good correlations with the heat treatment temperatures. Martensitic transformation temperature( M_s ) and Curie temperature ( T_C ) vary with the square of the degree of LRO. C_P and \lambda at room temperature are 29.5 Jmol ^{-1} K ^{-1} and 23.2 Wm ^{-1} K ^{-1} . CTE is ranged between 15 \times 10 ^{-6} K ^{-1} and 34 \times 10 ^{-6} K ^{-1} . Temperature dependence of these thermal properties is described.
Structural characteristics and magnetic properties of Fe-Pd thin films
Authors: Wang Z. , Iijima T. , He G. , Takahashi T. , Furuya Y.
Published: December 2018

Fe-30.0 mol%P The thin films were solution-treated at 1173 K for 60 s in vacuum and subsequently cooled by argon gas flow. The as-deposited thin films possess ultra-fine grains resulting in a long-range disorder structure. After the heat treatment, ( \gamma Fe, Pd) phase with an fcc structure is re-crystallized and the crystallized thin films show the texture orientation with (111) and (100) planes parallel to the surfaces of the thin films. Magnetic properties of the thin films are also affected by the crystal structure and grain size. The rectangularity of the hysteresis loop has been improved in the solution-treated thin films.
Magnetoelastic behavior of Ni-Mn-Ga martensitic alloys
Authors: Chernenko V.A. , L'vov V.A. , Pasquale M. , Besseghini S. , Sasso C. , Polenur D.A.
Published: December 2018

The magnetostriction measurements of almost stoichiometric single crystalline Ni _2 MnGa compound with T_m<T_C ( T_m and T_C are the martensitic and ferromagnetic transformation temperatures respectively) at constant temperatures have been performed in a temperature range of 100--400 K. The measurements resulted in a temperature evolution of magnetostrain, \varepsilon , with two extremums caused by soft mode condensation and martensitic transformation. Magnetic field induced strain of 0.4% In turn, the dilatometric mode of measurements along [100] under magnetic field (either constant or cyclic) led to 1.5% strain in martensite. Using a phenomenological approach both the anisotropic and volume magnetoelastic constants have been evaluated in cubic phase to be equal to - 1.2 MPa and - 0.4 GPa respectively. The experimentally observed smearing of Curie temperature in single crystalline Ni _{51.2} Mn _{31.1} Ga _{17.7} alloy with T_m>T_C is quantitatively explained by the spatially inhomogeneous mass density of martensitic phase and volume magnetostriction.
Faraday shielding in coaxial winding transformer
Authors: Lu Junwei , Wong Fu
Published: December 2018

This paper presents the configuration of a high frequency (HF) coaxial winding transformer with Faraday shield and discusses the shielding effect of the transformer in the high frequency range. The experimental results show the voltage ratio, coupling coefficient and load characteristic of the HF coaxial transformer in the range up to 2 MHz. The numerical result illustrates the eddy current distribution in the windings and shielding coil, and the magnetic flux distribution in the shielded HF coaxial transformer.
Editorial
Authors: Miya K. , Chen Zhenmao
Published: December 2018

Editorial to the special issue on the progress of eddy current based nondestructive testing.
Automated analysis of rotating probe multi-frequency eddy current data from steam generator tubes
Authors: Xiang P. , Ramakrishnan S. , Cai X. , Ramuhalli P. , Polikar R. , Udpa S.S. , Udpa L.
Published: December 2018

An algorithm is presented for the automated analysis of rotating probe multifrequency eddy current data obtained from nuclear power plant steam generator tubes (SGT). The algorithm consists of four steps, namely, a preprocessing stage for conditioning the data, a decision tree based feature extraction stage for identifying relevant features for analysis, a neural network based classification stage for identifying signals from various defect types and benign structures, and finally a blind deconvolution based characterization stage for accurately estimating the size and orientation of the detected defects. This algorithm is optimized to maximize the probability of detection (POD), while keeping the number of false alarms (PFA) at a minimum. Initial results presented in this paper look very promising and demonstrate the effectiveness of the proposed algorithm.
Magnetoelastic behaviour of a soft ferromagnetic ribbon in a silicone sheathing
Authors: Ausanio G. , Cuomo S. , Iannotti V. , Luponio C. , Lanotte L.
Published: December 2018

The effect of a silicone sheathing on the static and dynamic magnetoelastic properties of an amorphous ferromagnetic ribbon were experimentally investigated and some simple modelling of the detected behaviour are reported. Since silicone sheath and ferromagnetic ribbon do not form alloy, it is shown that internal friction between the two component has a determining role. In the presence of static friction, magnetisation and magnetoelastic wave amplitude are prevented by the silicone sheath; but after a threshold values of the magnetising field a dump occurs towards more easy magnetisation or higher amplitude of oscillations (in resonance condition), respectively. The magnetisation curve represents a step by crossing the threshold magnetising field value; this step is very flat so that it can be used for sensors of a little magnetic field change or as switch activated by little magnetic field input.

For what concerns the application of this two component material as resonator core it can be deduced that, also when a silicone sheath is present, the amplitude of resonant magnetoelastic wave is a good detector of stress, strain or local magnetic field; so that the application of magnetoelastic resonators made by amorphous ribbon core may be expanded to the cases which require a protection covering, as for example when it is necessary to work in water or in the human body.
Boundary-value problem of antiplane deformation of compound transversally-isotropic piezoelectric cylinder with cross section in form of circular sector
Authors: Galpchian P.V.
Published: December 2018

The electroelastic field arising in a compound cylinder in a state of antiplane deformation is investigated. The cylinder consists of two piezoelectric cylinder sectors glued with each other on the common part of their lateral surfaces. The materials of the component parts are assumed to be piezoelectrics of the hexagonal symmetry of class 6 mm with diverse physical properties.

The formulae for the components of the electrostatic field intensity vector and for the components of the mechanical stress tensor are obtained. On the basis of these formulae the electroelastic field in the vicinity of the angular point of the cylinder cross section contour is investigated when this point is on the division line.
Lorentz force-induced stresses in long current-carrying conductors
Authors: Deviatkin E.A.
Published: December 2018

Technique for calculation of Lorentz force-induced stresses in long straight conductors with the uniform current density in the presence of an external magnetic field is proposed. Reduction of the plane elastic problem for the conductor of a narrow rectangular cross section embedded in an arbitrary external field to the known homogeneous problems is considered. As an example stress analysis of an elliptical conductor with the stress-free lateral surface under the interaction of the current with its self field is performed and particular solutions of the problem of the interaction with the external field produced by the current flowing in an analogous conductor are given.
Numerical analysis of a low-profile rectangular spiral antenna
Authors: Nakano H. , Okabe Y. , Nakayama Y. , Yamauchi J.
Published: December 2018

This paper describes a rectangular spiral antenna backed by a conducting plane of finite extent. The distance between the spiral and the conducting plane is chosen to be extremely small: 0.07 wavelength at a test frequency of 3 GHz. For analysis, the finite-difference time-domain (FDTD) method is used. The radiation characteristics, including the current distribution, input impedance, radiation pattern, axial ratio, and gain, are revealed and discussed. It is found that absorbing materials inserted into the space between the conducting plane and the peripheral region of the spiral contribute to the wideband frequency characteristics of the axial ratio and input impedance.
Two-way shape memory effect and mechanical properties of pulse discharge sintered Ni_{2.18}Mn_{0.82}Ga
Authors: Takagi T. , Khovailo V. , Nagatomo T. , Matsumoto M. , Ohtsuka M. , Abe T. , Miki H.
Published: December 2018

Mechanical and shape memory properties of a polycrystalline Ni_{2.18}Mn_{0.82} Ga alloy prepared by a PDS (Pulse Discharge Sintering) method were investigated. It was found that the material demonstrates the two-way shape memory effect after a loading - unloading cycle performed in the martensitic state, i.e. essentially without special training. The samples exhibiting the two-way shape memory effect show a significant enhancement in the magnitude of magnetic-field-induced strain.
A PVDF piezopolymer sensor for unconstrained cardiorespiratory monitoring during sleep
Authors: Wang Feng , Tanaka Mami , Chonan Seiji
Published: December 2018

This paper presents an unconstrained sensing technique for the detection of the respiration and heartbeats during sleep using a piezopolymer PVDF film sensor with the aim that the sensor can be used on the ordinary bed together with the condition that the use of the sensor does not interfere the daily sleep of the patient under detection. A polyvinylidene fluoride (PVDF) film is used as the sensory material in the sensor system. The film is placed under the sheet at the location of the thorax to pick up the fluctuation of the pressure on the bed caused by the respiratory movement and heartbeats. Fundamental principle and the functional verification of the sensor system are described in details in the paper. It is shown that the respiration and heartbeats can simultaneously be detected by the sensor with the use of the wavelet decomposition analysis.
Response of a prestressed orthotropic thick plate subjected to an impulsive load
Authors: Nozawa Naotake
Published: December 2018

This paper concerns the dynamic response of an infinitely long thick plate. The plate is simply supported at the edges and subjected to initial in-plane stresses parallel and perpendicular to the edges. The plate is an orthotropic plate and rests on a viscoelastic foundation, where an impulsive line load excites it. Dynamic coefficients have been calculated and displayed graphically for several values of the initial stress parameters.
Control- performance improvement for magnetic fluid type semi-active damper
Authors: Nakagawa Toshiko , Itoda Koji , Furukawa Tadashi , Futami Shigeru
Published: December 2018

In the previous paper [1], a novel type of semi-active damper that is composed of a cylinder injected with Magnetic Fluid (M.F.) and a magnetic flux controller was proposed for improving the ride comfort of trains. In this paper, at first, a modified model considering nonlinear characteristic of M.F. such as a Non-Newtonian-Fluid is proposed. Next, in order to enhance the control effects, two kinds of improvements are made in the semi-active damper. One is to change the voltage control input to an electromagnet into the current control input. The other is to expand the control range for the M.F. damper by means of feeding a bias current to the electromagnet. Finally, the effects of the improved semi-active damper are shown by various digital simulations and vibration experiments.
A study on vibration control of steel strips by using only current sensors
Authors: Imai Hidekazu , Tanaka Tomomichi , Nakagawa Toshiko
Published: December 2018

In the process line of a strip belt, it is desirable to reduce contacts between rollers and steel strips to produce better quality. In addition, it is also desirable to hold the shape or to suppress vibration with as little contact as possible. This paper proposes a model apparatus for controlling vibration without any contact. It aims to use economic and compact current-sensors instead of expensive gap ones and also the controlled attractive force of electromagnets. This paper investigates the effects for the several types of vibration control effects for the strips by digital simulations and experiments.
Elastic vibration of steel plate with magnetic force for restraining horizontal position in magnetic levitation
Authors: Igusa Atsushi , Oshinoya Yasuo , Ishibashi Kazuhisa
Published: December 2018

It has been confirmed that a thin steel plate can be levitated by controlling the current of electromagnets. However, the plate gets out of position in the case of high-speed conveyance of the steel plate if there is no force for restraining the plate from slipping horizontally. Then, electromagnets for controlling the horizontal position are installed. In this paper, we study how the elastic vibration of the steel plate is affected by the magnetic field produced by the electromagnets. The magnetic force pulls back the steel plate to its center. With the magnetic field produced by the electromagnets, the frequency of the vibration increases and the vibration is attenuated more rapidly. In addition, the tensile force makes the steel plate flat.
Stress-magnetization change in amorphous ribbon due to magnetic field heat treatment
Authors: Iwami Yoshio , Okazaki Yasuo , Saito Akihiko
Published: December 2018

Stress-magnetization changes in Co-based amorphous ribbons annealed under magnetic field (magnetic field heat treatment) have been investigated. The stress-magnetization changes due to tensile stress were observed in positive increment of magnetization for the sample annealed under transversal magnetic field to its ribbon axis. However, a Co-based amorphous ribbon annealed under applied magnetic field parallel to the ribbon axis (longitudinal direction) did not show positive magnetization increment under applied tensile stress but showed stress insensitive region in magnetization change, which extended with increasing annealing temperature.
Advanced permanent magnet machine design and construction for wind power generation and traction applications
Authors: Koutroulis Ch. , Kladas A.G. , Mamalis A.G.
Published: December 2018

The paper presents the optimization procedure of permanent magnet electrical machines, presenting important advantages in wind power generation and traction applications. Both "Internal" low remanence permanent magnet and"Peripheral" Neodymium alloy magnet rotor structures have been considered and compared. Design optimization has been performed based on the finite element method and sensitivity analysis techniques. The developed methodology precision has been checked through measurements on a 2 kW electrical machine prototype and the good agreement with the experimental results illustrates the method suitability for permanent magnet machine design.
High-coercivity Nd_{90-x}Fe_{x}Al_{10} bulk amorphous alloys
Authors: Chiriac H. , Lupu N. , Takeuchi A. , Inoue A.
Published: December 2018

Extensive magnetic studies on Nd _{90-x} Fe _{x} Al _{10} (x = 35 ∼ 50) amorphous alloys in the shape of both melt-spun ribbons with thicknesses between 25 and 150 μm and rods with diameters no larger than 3∼mm prepared by mould casting and suction casting indicate a complex magnetic behaviour depending on the Fe content. The microstructure and magnetic properties are strongly dependent on the cooling rate and the preparation technique. The high values of the coercive field of Nd _{90-x} Fe _{x} Al _{10} amorphous samples in the as-cast state as well as their increase by the decrease of the cooling rate and temperature result from the formation of very small metastable or non-equilibrium clusters, whose size vary as a function of the quench rate. The presence of these magnetic clusters is evidenced by multiphase magnetic transitions observed from the ac-susceptibility measurements at low temperatures.
The influence of Mo addition and thermal treatment on the Hall effect and magnetoresistance of Co_{68.25-x}Fe_{4.5}Si_{12.25}B_{15}Mo_{x} alloys
Authors: Chiriac Horia , Lozovan Mihai , Neagu Maria , Hison Cornelia , Lupu Nicoleta
Published: December 2018

Results concerning the influence of Mo addition and thermal treatment on the Hall effect and magnetoresistance of Co _{68.25-x} Fe _{4.5} Si _{12.25} B _{15} Mo _x (x=1; 2) ribbons in the amorphous, nanocrystallized and crystallized states are reported. The value of the Hall resistivity of the samples increases continuously with applied magnetic field up to about 7 kOe and 13 kOe for Co _{67.25} Fe _{4.5} Si _{12.25} B _{15} Mo _1 and Co _{66.25} Fe _{4.5} Si _{12.25} B _{15} Mo _2 alloys, respectively and then it approaches saturation. For Co _{67.25} Fe _{4.5} Si _{12.25} B _{15} Mo _1 ribbons the ferromagnetic anisotropic resistivity (FAR) values are 2.78 × 10^{-4} , 2.60 × 106^{-4} and 2.84 × 10^{-4} for amorphous, nanocrystalline and crystalline states, respectively. The FAR values of Co _{66.25} Fe _{4.5} Si _{12.25} B _{15} Mo _2 ribbons are 1.35 × 10^{-4} , 1.78 × 10^{-4} and 18 × 10^{-4} for amorphous, nanocrystalline and crystalline states, respectively.
Active magnetic shielding with magneto-impedance sensor
Authors: Okazaki Yasuo , Yanase Shunji , Sugimoto Noriko
Published: December 2018

Active shielding effect was examined in a negative feedback circuit system consisting of a magneto-impedance effective sensor, an amplifier and a canceling coil to compensate external magnetic field noise. The frequency dependent active shielding effectiveness depends on the phase difference between the input and output sensor signals in a loop, whch were less than 90 degree up to 20,000 Hz. An excellent characteristic of active shielding effectiveness of 48 dB was obtained for the external magnetic field noise from dc field to the frequency of 2,000 Hz.
Theoretical background of parallel electromagnetic field computations
Authors: Jordan Andrzej
Published: December 2018

This paper presents a general concept of electromagnetic field parallel computations using super-computers and cluster system of workstations. In principle, all numerical algorithms of electromagnetic field computations(FEM, FDM, FEBM, FDTD) lead to the analysis of a large set of algebraic equations. The properties of parallel implementation of FDTD algorithm and the conjugate gradient method (CGM) were presented.
Emission of high-energy electrons from moderately underdense plasmas produced by TW-fs laser pulses
Authors: Koyama Kazuyoshi , Hazama Hisanao , Saito Naoaki , Tanimoto Mitsumori
Published: December 2018

Self-focusing of the intense laser pulses as well as production of the well-collimated electron beams in the moderately underdense plasma of n_{e}/n_{c} ≥ 10% 7 × 10^{17} W/cm ^{2} . Progresses of a relativistic self-focusing in the plasma of a gaussian density profile were observed by an ultra-fast optical probing. Even if the large gas-target of the quasi-uniform density was used, the self-focusing was terminated after traveling approximately 1.2 mm by the abrupt transition of the propagation mode from the smooth channeling to the complex filamentation, which correlated with the emission of MeV-electron beams. High-energy electron beams have the power-law spectrum of E^{-3.5} reaching the maximum energy of 2 MeV. The maximum number of the electrons was (1.3 ± 0.6) × 10^{11} /sr/shot. Model calculations suggest that the most plausible mechanism of the production of high-energy electron beam in the moderately underdense plasma is that the phase of the electron oscillation in filaments of the laser beam randomly changes many times.
Nano-beam production by RFQ with ion-trap injector
Authors: Ito Kiyokazu , Ogata Atsushi , Okamoto Hiromi
Published: December 2018

We describe a possible accelerator system to provide an ion beam of extremely low emittance and low current. It is possible to reduce the beam size down to nanometer order keeping the beam divergence of microradian order. It can be used as a nano beam source for single ion implantation onto semiconductors and for the systematic study of radiation damage in bio-molecules and semiconductors. The whole system basically has a radio-frequency quadrupole configuration with a Paul ion trap as injector. Ions are confined and cooled in the trap section, and then accelerated to∼ MeV through an RFQ linac. Design speculation is made assuming acceleration of ^7 Li ^+ ions.
Time-resolved X-ray diffraction for visualization of atomic motion
Authors: Kinoshita Kenichi , Ohkubo Takeru , Yoshii Koji , Harano Hideki , Uesaka Mitsuru
Published: December 2018

For ultrafast material analyses, we constructed the time-resolved X-ray diffraction system utilizing ultrashort X-rays from laser produced plasma generated by the 12TW-50fs laser at Nuclear Engineering Research Laboratory. Ultrafast transient changes in laser-irradiated GaAs crystals were observed as X-ray diffraction patterns. A subpeak appears in X-ray diffraction profiles and shifts its position gradually as time goes in the case of 1.3 mJ/mm ^2 laser fluence. Experimental results were compared with numerical analyses to infer the atomic arrangement during the transition.
Fabrication and test of a small experimental superconducting homopolar machine with axially laminated rotor disks
Authors: Ishigohka Takeshi , Ninomiya Akira , Hayakawa Kihachiro , Mitsuhashi Tsukasa
Published: December 2018

In order to examine the fundamental availability of a homopolar machine with laminated armature rotor disks, the authors fabricated and tested a small superconducting experimental homopolar machine with two rotor disks. The machine was tested as a generator. The obtained experimental data show that the output voltage of the 2-disk machine is about 2 times larger than that of the 1-disk machine. From this experimental result, we can conclude that the output voltage of a homopolar generator with axially laminated rotor disks is proportional to the number of the disks.
Effect of magnetic field on nitric oxide synthesis of cultured endothelial cells
Authors: Sakamoto Naoya , Ohashi Toshiro , Sato Masaaki
Published: December 2018

The effect of magnetic field on nitric oxide (NO) production of cultured human umbilical vein endothelial cells (HUVECs) was investigated. Static magnetic fields (30 mT, 300 mT) and an oscillating magnetic field (30 mT, 20 Hz) were applied to HUVECs for 0.5, 1 and 6 hours and intracellular NO was observed using a fluorescent indicator. There was no effect of the static magnetic field on the NO production of the HUVECs. In contrast, the NO production increased with applying the oscillating magnetic field for 0.5 hour. However, such an increase of NO production was not observed for 1 and 6 hours. We performed a separate experiment to clarify the mechanism of NO synthesis by using an inhibitor of calcium-independent activation of NO synthase. The inhibitor suppressed the increase of NO production caused by the oscillating magnetic field. It can be concluded that oscillating magnetic field may activate calcium-independent pathway of activation for NO synthase.
Manipulation of cells by diamagnetic energy
Authors: Iwasaka Masakazu , Ueno Shoogo
Published: December 2018

The diamagnetic torque energy of the smooth muscle cell, endothelial cell, and an extra-cellular matrix, such as collagen, which form blood vessel, exhibited a conformational change in cells under static magnetic fields of up to 14 T. As a tool to develop new medical applications of strong magnetic fields, the magnetic manipulations of cells by diamagnetic energy were discussed.
Computer modeling of transcranial magnetic stimulation
Authors: Starzyński Jacek , Sawicki Bartosz , Wincenciak Stanisław , Krawczyk Andrzej , Zyss Tomasz
Published: December 2018

The paper attempts to create a mathematical model of the transcranial magnetic stimulation (TMS), the technique that aims at replacing the electro-convulsive treatment (ECT) in the therapy of deep depression.

The magnetic field calculation is based on the T-Ω formulation, which, due to low electric conductivity and constant magnetic permeability of the brain tissue, allows us to build finite element model of the head only.
Numerical analysis of a steady magnetic fluid flow taking into account nonuniform distribution of mass concentration and prorate ellipsoids under a nonuniform magnetic field
Authors: Shimada Kunio , Syuchi Narimitsu , Kamiyama Shinichi , Yamaguchi Hiroshi
Published: December 2018

Numerical analysis of a steady magnetic fluid flow in a straight pipe is made by taking into account nonuniform distribution of mass concentration and formation of prorate spheroids of magnetic particles under a steady nonuniform magnetic field. The local shear rate, number of aggregated particles as a prorate spheroid and fluid velocity distribution are obtained to be clarify that their large change exists at the down stream area of the magnetic field. The relation of wall friction to Reynolds number shows good agreement with the experimental data.
Thermal behavior and cluster formation of ferromagnetic particles in magnetic fluids
Authors: Tachibana Toshihide , Kikura Hiroshige , Matsuzaki Mitsuo , Yamanaka Gentaro , Aritomi Masanori , Kobayashi Yuji , Nakatani Isao
Published: December 2018

Thermal behavior and cluster formation of ferromagnetic particles in the water-based, kerosene-based and alkyl-naphthalene-based magnetic fluids were investigated using an optical microscope system. Real-time visualization of the Brownian motion and the chain-like cluster formation of three types of particles were carried out under a magnetic field. The influence of the magnetic field intensity and the temperature variation on cluster formation of ferromagnetic particles was investigated.
Design of an artificial sphincter using shape memory alloys
Authors: Luo Yun , Takagi Toshiyuki , Matsuzawa Kenichi
Published: December 2018

An artificial sphincter using shape memory alloys (SMAs) has already been proposed by the authors [1]. Thermomechanical properties of the artificial sphincter have been evaluated experimentally. The main work of the present paper is to conduct numerical computation using finite element method(FEM) to simulate the thermomechanical behavior of SMA plates used in artificial sphincters, and to investigate the relation between the applied power and thermomechanical responses, for the design purpose.
Special problems of electromagnetic-acoustic transducer for material non-destructive testing
Authors: Čápová Klára , Čáp Ivo , Faktorová Dagmar
Published: December 2018

The present paper deals with the utilization of the electromagnetic-acoustic transducer (EMAT) for the non-destructive testing of conducting materials. The principle of the EMAT consists in the interaction of the electrodynamic structure of materials with an external electromagnetic (EM) field under influence of a bias magnetic field. It offers the possibility to generate an acoustic mode of the penetrating EM wave with the slow velocity and the attenuation of the acoustic wave or on the other hand to detect the EM wave due to its radiation from the surface of a conducting sample. The main advantage of the EMAT is the contactless generation and detection of the acoustic wave, or the acoustic mode of EM wave in a wide range of frequencies and temperatures. The special properties of EMAT's driving and detecting devices are presented in the paper.
Numerical analysis of joint inspection using electromagnetic acoustic transducers
Authors: Itoh Hitoshi , Sugiura Toshihiko , Maruyama Shinichi , Yokota Shuhei , Enoeda Mikio
Published: December 2018

Engineering use of jointed materials requires quantitative inspection of the joints, though it has not been established yet. Electromagnetic acoustic transducers (EMATs) can generate and detect ultrasonic waves in a conductive specimen by electromagnetic coupling without any contact with a specimen. This feature gives EMATs an advantage over conventional ultrasonic transducers: theoretical modeling and formulation based on elastodynamics and electromagnetics can be obtained. In this research, a process of joint inspection using EMATs was analyzed numerically. Numerical results of the wave propagation explain effects of the joint interface and of a joint failure on the propagation of ultrasonic waves and on the receiver signals, in terms of reflection and diffraction of the waves. Predicted receiver signals agree well with experimental results, which verifies our numerical approach. These results show a possibility of quantitative joint inspection using EMATs.
Experimental measurements of ID and OD signals in welds using magnetic methods
Authors: Mihalache Ovidiu , Chen Zhenmao , Cranganu-Cretu Bogdan , Miya Kenzo
Published: December 2018

The paper presents new developments in the detection of inner and outer defects in welds by using magnetic methods. A new yoke based on permanent magnets was designed. Signals from different types of cracks, inner and outer, are measured. Difficulties arising in detection of outer defects, in thick welded parts are also discussed.
Running characteristics of permanent magnet linear synchronous motor energized by partially excited primary current
Authors: Jung Sang-Yong , Jung Hyun-Kyo
Published: December 2018

Running characteristics of permanent magnet linear synchronous motor(PMLSM) which is usually used in the system requiring the high acceleration and the accurate position precision are investigated. Also, employment of partial excitation of primary current according to the mover position for the efficient motor drive, and its influence on the EMF and thrust force ripple are considered in detail. Furthermore, capability of PMLSM manifesting the speed-force feasibility under the running condition will be followed.
Directional sensitivity of GMR element and its industrial applications
Authors: Wakiwaka Hiroyuki , Kataoka Yasuhiro , Shinoura Osamu
Published: December 2018

Giant magneto-resistive (GMR) elements are applied to several industrial magnetic sensors. This paper deals with the directional sensitivity of GMR elements, and their industrial applications. The use of GMR element has several advantages for other sensors. In the area of data storage, GMR elements are generally used to detect the magnetic field impressed in the direction of the stripe width. However, the GMR element has high sensitivity in the direction of the length as well as the width, even if it is a stripe shape. In addition, we obtain an omnidirectional sensitivity of GMR elements. Using the GMR element, we developed a GMR line sensor. This sensor visualized a magnetic field by only a single scan.
A boundary-oriented inverse scattering method based on contour deformations by means of level sets for radar imaging
Authors: Ferrayé Ralph , Dauvignac Jean-Yves , Pichot Christian
Published: December 2018

A boundary-oriented method for 2D electromagnetic inverse scattering in TM polarization and time-harmonic dependence is presented for perfectly conducting objects [1,2]. Key points of the method include a kinematical description of the contours of the objects, the introduction of pseudo-currents to ensure stability and the use of a level set method for deforming the contours. Level set methods [3] allow to handle automatically the changes of topology and to regularize naturally the contours. In this way, several objects can be retrieved starting from one single initial guess. The frequency hopping technique turns out to play a very important role in the inversion process. This method gives highly accurate reconstructions within relatively short computational times.
Shape recovery of natural crack using evolutionary programming related to eddy current testing
Authors: Kojima Fumio , Kubota Naoyuki , Kobayashi Futoshi , Takagi Toshiyuki
Published: December 2018

This paper is concerned with a shape recovery of natural cracks in steam generator tubes of the PWR nuclear power plant. A three dimensional forward model is developed for analyzing accurate probe response evaluation in eddy current testing. Using the evolutionary programming, an efficient inverse scheme is proposed for recovering natural cracks. The proposed algorithm is tested for stress corrosion cracks of the steam generator tube samples.
Identification of delamination in layered composite materials by the electric potential CT method
Authors: Kubo Shiro , Kuchinishi Manabu , Sakagami Takahide , Ioka Seiji
Published: December 2018

The electric potential CT (computed tomography) method proposed by the present authors was applied to the identification of delamination defect in layered carbon fiber reinforced plastics (CFRP) composites, which have strong anisotropy in electric conductivity. The electric potential readings on the top surface of the layered composite materials was used for the identification. The anisotropy of the electric conductivity of each layer was taken into account in the boundary element calculations of electric potential distribution. Numerical simulations were made on the identification of elliptical delaminations on the interface of layers. It was found that the method was applicable for the estimation of the location and size of delamination even in the presence of considerable measurement noise.
Characterization of material degradation and detection of imperfections inside of thick walled austenitic components with electromagnetic testing
Authors: Weber W. , Feiste K.L. , Reimche W. , Stegemann D.
Published: December 2018

A wide range of pressurized systems in the field of chemical and power-plant techniques are made of austenitic material because of its special corrosion and temperature stability. Concerning safety components like pressure vessels and pipe systems, the quality of these components has to be controlled during production, and their condition during use has to be inspected in defined intervals. Especially for nuclear power plants, the detection of defects as well as the early recognition of material phase transformations in austenitic material is an important contribution to the assurance of the system integrity. Inside this paper, the results of the qualitative and quantitative non-destructive evaluation of this phenomenon will be presented. Therefore, material physics, FEM-calculations and applied advanced electromagnetic testing techniques will be explained.
Stress around crack tip induced by electromagnetic force in DSCu/SS316 HIP bonded structure
Authors: Kohno H. , Watanabe K. , Nomura Y. , Saito M.
Published: December 2018

The component of ITER facing directly to plasma is called the first wall. The first wall is composed of DSCu/SS316 HIP bonded structure. In addition to residual stress due to the HIP bonding process the electromagnetic force is loaded on the first wall during plasma disruption. In this study, we assume an initial crack in the first wall. Stress induced by the electromagnetic force at the crack tip is estimated by finite element method taking the residual stress into consideration. From a viewpoint of fracture mechanics, stress intensity factor K is evaluated to make sure the structural integrity of the DSCu/SS316 HIP bonded structure. As a result of analyses, the stress intensity factor K is not so large for all of the assumed cracks. Therefore, there is no possibility of fracture due to the crack growth during the lifetime of the first wall.
Feature extraction of particle density in a pipeline with tomography and wavelets
Authors: Takei Masahiro , Li Hui , Ochi Mitsuaki , Saito Yoshifuru , Horii Kiyoshi
Published: December 2018

A concept to extract a feature of solid-air two-phase flow in a pipeline has been launched with a combination of a capacitance-computed tomography and wavelets transform. With this concept, particle distribution images obtained by CT are transformed with discrete wavelets multiresolution. As a result, in the case of low open area ratios of the pipe cross-section, high particle densities are shown in secondary dominant levels as well as a substantial space level. The high value in the secondary level resulted from inhomogeneous density due to collision between particles.
Magnetic domain dynamics visualization
Authors: Endo Hisashi , Hayano Seiji , Fujikura Masahiro , Mogi Hisashi , Kaido Chikara , Saito Yoshifuru
Published: December 2018

This paper proposes a visualizing methodology of iron loss generation in a magnetic material using its visualized domain images, i.e., SEM, Kerr and Faraday effects. Based on the differential equations for dynamic image, the material behavior is visualized. The state transition matrix of the Helmholtz equation, for which is derived from a series of distinct visualized domain images representing magnetized state. This makes it possible to visualize the magnetizing mechanism as well as iron loss generation. In the present paper, visualization of iron loss generation on a grain-oriented electrical steel sheet is worked out using a set of SEM images. As a result of our image analysis, magnetization curves at the particular points can be estimated.
How to read a novel
Authors: Morohoshi Noriko , Endo Hisashi , Saito Yoshifuru , Horii Kiyoshi
Published: December 2018

When reading a novel by EKUNI Kaori, reader's world in the brain has been clarified by means of the discrete wavelet analysis. According to the analysis, reader's world in the brain has been classified into two layers. One is the world in the book and the other is the existing real world. Major target of this paper is to visualize the transition states between two layers. As a result of our analysis, it has been revealed that the wavelet multi-resolution analysis has made it possible to visualize the transition states as well as to clarify the composing methodology of the novel.
Application of the Fourier-wavelet transform to moving images in an interview scene
Authors: Kato Chieko , Endo Hisashi , Saito Yoshifuru , Horii Kiyoshi
Published: December 2018

A new computer-aided method, based on Saito's Fourier-wavelet theory, is used to extract the facial expressions that appear and disappear in less than one-fifth of a second, i.e. expressions that reveal the true emotions of a human being. The new method consists of two major steps. The first step is the application of the Fourier transform to reduce the spatial phase differences between the reference and test images. The second is the application of the wavelet transform to extract the local discontinuous differences. This method is applied to the moving images in the interview scene. Using this method, the difference between the two facial expressions has been extracted, even though both images differ in their size and reference position.
Analysis of static angle error of 2X-VR type Resolver depending on leakage flux
Authors: Kitazawa Kanji , Kikuchi Yoshimi , Mimura Hisashi , Makiuchi Hiromi , Kamiya Akinori , Wakiwaka Hiroyuki
Published: December 2018

The VR type Resolver is an angle sensor for the motor of electric vehicles and hybrid electric vehicles. The static angle accuracy of the Resolver affects the dynamic error during rotation of the motor. Therefore, for the purpose of reducing the static error of the Resolver, the cause of error was investigated by means of experiment and FEM analysis, especially regarding the effect of leakage flux distribution around the coils. As a result, it became evident that the flux distribution in stator slots is not equal, thus uniform winding and balance between 2-phase output coils are needed.