bluuebunny/crossref_metadata_2025 huggingface dataset:
A W-band broadband single balanced mixer using an improved 180-degree hybrid
Authors: Zhao Wei , Zhang Yong , Li Li , Liu Shuang , Xu Ruimin
Published: December 2018

In this paper, an improved wideband millimeter-wave 180° hybrid is proposed and a novel W-band broadband single balanced mixer based on the new hybrid is presented. The proposed hybrid consists of a standard waveguide to suspended coplanar waveguide (SCPW) transition and a SCPW to suspended stripline transition. According to the inherent electromagnetic field characteristics of the two transitions, the proposed hybrid achieves good performances of broadband phase, power distribution and isolation. The simulated insertion losses of the two transitions and the isolation between the two signal input ports are better than 0.1 dB and 54 dB respectively. A single balanced mixer based on the proposed hybrid has been designed and fabricated at W-band. The measured single-sideband (SSB) conversion loss is less than 9.5 dB for the radio frequency (RF) range from 80 to 108 GHz. And the best SSB conversion loss of 5.8 dB is achieved with RF of 104 GHz. Moreover, the local oscillator (LO)-RF isolation is more than 30 dB over the overall W-band. The results show that the fabricated mixer has the advantages of broad bandwidth, low conversion loss, and good isolation.
Compact dual-band bandpass filter using complementary hook-shaped resonators for WLAN applications
Authors: Zhang Z. , Jiao Y.C. , Weng Z.-B. , Wang X.-M.
Published: December 2018

Based on the double resonant properties of the complementary hook-shaped resonator (CHSR), a novel miniaturized dual-band microstrip filter is proposed for WLAN operations. The filter, which is only 0.067λ _0 × 0.084 λ _0 in overall dimensions, is composed of two opposite CHSRs and modified T-shaped feed-lines. Two hook-shaped strips generate two respective passbands, independently. The proposed filter is found to have two transmission zeros around the high resonances for improved selectivity. To verify the proposed method, a dual-band filter is implemented and measured, and the measurement results agree well with the simulated data.
Fuzzy neural network multi-modal vibration control of thin cylindrical shells laminated with photostrictive actuators
Authors: He Rongbo , Zheng Shijie
Published: December 2018

In this paper, the multi-modal vibration control of a simply supported thin cylindrical shell laminated with photostrictive actuators is studied. First, the photo-electric/shell coupling equations of a cylindrical shell laminated with the multi-layer actuator configuration are presented. Moreover, in view of the nonlinear and time-variant characteristics of photostrictive actuators, a fuzzy neural network (FNN) controller with adaptive learning rates is developed to attenuate multi-mode vibration of photo-electric laminated thin cylindrical shells. This approach has learning ability for responding to the time-varying characteristic of the multi-mode vibration induced by disturbance. Its control rule bank can be established and modified continuously by on-line learning. Finally, numerical simulation results are provided to show that the proposed intelligent controller could effectively suppress multi-mode vibration of photo-electric laminated thin cylindrical shells.
Photostrictive mathematical model of PLZT ceramics: Constitutive modeling and experimental validation
Authors: Wang X.J. , Huang J.H. , Wang J. , Yue H.H.
Published: December 2018

Lead lanthanum zirconate titanate (PLZT) ceramics can transform the light energy into the mechanical energy without electromagnetic noise. The optical and direct driven based on PLZT's photostrictive effect, which is also green driven and non-contact driven, has many advantages in micro-driven and structure vibration control. However the existing constitutive equations of PLZT ceramics do not consider the influence from both light intensity and PLZT ceramic sizes (i.e. length, width and thickness) to photostrictive effect. In this paper, the effect of the light intensity, aspect ratio and the thickness of the PLZT ceramic on the photostrictive strain is researched based on the equivalent electrical model of the PLZT. A new photostrictive mathematical model of PLZT with LED-UV illumination is established. The mathematical model is validated through the photostrictive static experiments of PLZT samples with various sizes and light intensities.
Electromagnetic responses of a metallic conical frustum cabin with one coaxial feeding monopole antenna
Authors: Wang Jian , Xia Yin-Shui , Wang Lun-Yao
Published: December 2018

Electromagnetic responses of a metallic conical frustum cabin with one coaxial feeding monopole antenna, illuminated by an intentional electromagnetic pulse (IEMP), are studied in this paper. There are several slots on the cabin wall with different sizes and orientations. The mathematical treatment is based on novel hybrid finite difference time domain (FDTD) method, where coaxial feeding, transfer impedance coupling and thin wire antenna models are integrated together for handling such a complex three-dimensional (3D) composite structure. The revised antenna port coupling model is verified by comparing the calculated terminal voltage responses of the coaxial feeding cable with that of commercial CST Microwave Studio. Parametric studies are further carried out to show the variations of its terminal voltages for different IEMP waveforms, incident directions and polarizations.
Coupled multiphysics circuital modelling of quasi resonant induction cooktops
Authors: Dughiero F. , Forzan M. , Pozza C. , Pastore C. , Zerbetto M.
Published: December 2018

Induction cooktops are more and more used in the houses with increasing market in comparison with gas cooktops and resistance or halogen cooktops. The main reasons for this are the higher energy efficiency, the low heating times, the controllability of the power delivered to the pot, the safety with reference to the low temperature of the glass, the superior cleanability. The main core of the Induction Hob (IH) is constituted by the power electronics board and the inductor which are strictly correlated in the sense that the frequency converter (the frequency operating range is 20–100 kHz) must be designed in order to correctly resonate with the coil in order to achieve its optimum efficiency over the broadest possible operation range; this means that the inductor must be designed in order to fulfill the Zero Voltage switching condition of the frequency converter over the whole range of operation. These requirements are much more important in the quasi resonant converters for the limitations in the controllability of soft switch mode of solid state switching. In the paper a design procedure based on a fully 3D FEM model of the inductor coupled with the frequency converter circuit is presented. The simulation results will be discussed and compared with experimental data.
High heat generation ability in AC magnetic field of nano-sized superparamagnetic Y_3Fe_5O_12 ferrite powder prepared by physical bead milling
Authors: Aono Hiromichi , Naohara Takashi , Maehara Tsunehiro , Hirazawa Hideyuki
Published: December 2018

Nano-sized superparamagnetic Y _{3} Fe _{5} O _{12} ferrite having a high heat generation ability in an AC magnetic field was prepared by physical bead milling. The highest heat ability in the AC magnetic field was for the fine Y _{3} Fe _{5} O _{12} powder with a 16-nm crystallite size (the samples were milled for 4 h using 0.1 mm� beads). The main reason for the high heat generation property of the milled samples was ascribed to an increase in the Néel relaxation of the superparamagnetic material. For the samples milled for 4 h using 0.1 mm� beads, the heat generation ability (W·g ^{-1} ) was estimated using a 3.58 × 10 ^{-4} · f· H ^{2} frequency (f/kHz) and the magnetic field(H/kA·m ^{-1} ), which is the highest reported value of superparamagnetic materials. Furthermore, Y _{3} Fe _{5} O _{12} microspheres having a 20–32 μm diameter range were prepared by a spray dryer using the bead-milled nano-sized particles.
Investigations on temperature distribution during revolutionary and zigzag movement of arc in magnetically impelled arc butt welding of tubes
Authors: Arungalai Vendan S. , Thangadurai V. , Vasudevan A. , Senthil Kumar A.
Published: December 2018

The arc in MIAB welding process follow two paths of motion, one along the circumference and other comprising the zigzag motion when commuting between outer diameter and inner diameter. The moving arc dissipates necessary heat such that the butt ends reach solidification followed by forging. In this study, a pivotal attempt is made to investigate the temperature distribution during the movement of arc along and across the faying surfaces using finite element method.
Three-dimensional MHD modeling of railgun plasma armature with the CE/SE method
Authors: Gong Fei , Li Xin , Weng Chun-Sheng
Published: December 2018

Three-dimensional (3-D) numerical simulations have been carried out taking into account the magnetohydrodynamics (MHD) effect of the railgun plasma armature. The 3-D space-time conservation element and solution element (CE/SE) method is derived for solving the coupled Navier-Stokes equations and Maxwell equations. The results show that a steeper gradient of the magnetic field and pressure that appears along the direction of the rail can be observed. The temperature distribution is affected by the boundary conditions for the radiative heat flux, with the maximum temperature appearing in the center near the base of the projectile. Circulation patterns of velocity that are evident in both the rail-to-rail plane and the insulator-to-insulator plane result from the convection and unbalanced force between the Lorentz force and pressure gradient. The periodical variation of the temperature and acceleration is obvious until a new steady state is achieved. This model can efficiently evaluate the dynamics of the plasma motion, and provide a basis on understanding the much more complex physical phenomena.
International comparison of measurements of hard magnets with the Vibrating Sample Magnetometer
Authors: Fiorillo F. , Beatrice C. , Son D. , Ahlers H. , Groessinger R. , Albertini F. , Liu Y.P. , Lin A. , Patroi E. , Shull R. , Thomas O. , Hall M.J.
Published: December 2018

We present the results of an international comparison regarding the magnetic properties of hard magnets, measured using the Vibrating Sample Magnetometer. The comparison involved eight different international laboratories, plus two laboratories using the SQUID magnetometer. It was directed, in particular, at the determination of the hysteresis loop parameters of hard ferrite and magnetic tape samples. It was carried out in the framework of the activity of the IEC TC68 Working Group 2. The statistical analysis of the obtained results was performed according to standard rules (e.g. ISO and EURAMET guidelines). The standard deviation around the mean of the laboratories best estimates is found to be s ∼ 1% in anisotropic ferrites for all the measured quantities: coercive fields H _{cJ} and H _{cB} , high-field polarization J _{800 k} , polarization at remanence J _r , maximum energy product (BH) _{max} . Isotropic ferrites show larger dispersion of the best estimates of J _r and H _{cB} (∼ 3%) and (BH) _{max} (∼6%). For the quantities measured in the magnetic tapes (magnetic moment under applied field H=400 kA/m m_{400 k} and at remanence m_r , squareness S = m_{400 k}/m_r , H _{cJ} ) s is found to fluctuate around 2%. In all cases, the relative expanded uncertainty of the reference value (weighted mean), associated with a 95% confidence level, is at most ± 1.5%.
Studies on the systematic error of Epstein measurements
Authors: Sievert J. , Yang H. , Zhang P. , Ge H.
Published: December 2018

The standardized Epstein frame is a magnetic circuit for the normative measurements of magnetic properties of electrical sheet steel following the Wattmeter method. It was designed for convenient practical use in industry rather than as an accurate physical representation of magnetic power loss of the material. In principle, the Wattmeter method is based on the use of a homogeneous ring sample as the magnetic circuit. The double overlapping corners of the Epstein frame constitute a significant divergence from the topology of the homogeneous ring, and, thus, are the source of a substantial systematic error. This paper applies the simple method of summation of the reluctances of the complete magnetic circuit (CRS) for the determination of this error. The results for various types of electrical steel and for the frequency range of 40 Hz to 100 Hz are considered. Results of variations of the Epstein strip stacking scheme are also recorded.
Analysis of vector magnetic property and two-dimensional magnetostriction in electrical steel sheets
Authors: Wakabayashi Daisuke , Enokizono Masato
Published: December 2018

Vector magnetic properties and two-dimensional magnetostrictions of electrical steel sheets under alternating and rotating magnetic flux conditions were measured. Based on the measured database, magnetic characteristic analyses of motor and transformer model cores have been carried out and distributions of two-dimensional magnetostriction have been estimated. The proposed method has been verified with a ring specimen in comparison of the analyzed result with the measured one.
Rise-of-temperature method for building factor distribution in 1-phase model transformer core interior considering high DC bias
Authors: Hofbauer Franz , Pfützner Helmut , Shilyashki Georgi , Šabić Damir , Mulasalihović Edin , Galabov Viktor
Published: December 2018

Loss distributions of transformer cores are affected by z-flux effects if considered for the core surface. Here we propose the application of a thermal sensor which is inserted to the core interior through one of 16 channels of 2 mm width. Measurements were made on a 1-phase core assembled from laser-scribed SiFe. Throughout the core, the local building factor BF proved to increase towards the periphery which can be interpreted by interactions of highest anisotropy and non-linearity. Additional DC superposition yields non-uniform increases of BF at different core positions. Local losses tend to become more balanced – measurement locations with a priori high BF experience lower percentage increases, being more robust with respect to DC components.
Influence of shear stress on vector magnetic properties of non-oriented electrical steel sheets
Authors: Kai Yuichiro , Enokizono Masato , Kido Yukihito
Published: December 2018

Electrical steel sheet that is used as a core in electrical machines deteriorates due to residual stress and external stress. The magnetic properties and stress need to be clarified in order to effectively utilize electrical steel sheet in electrical machines. We have measured the residual stress distribution in a motor core using an X-ray stress measurement device and clarified not only the tensile and compressive stress distributions, but also the shear stress distribution. In this study, a new measurement system is developed for determining vector magnetic properties under shear stress. The vector magnetic properties of the non-oriented electrical steel sheets under the alternating magnetic flux and rotating magnetic flux conditions were measured with the developed system. As the result, it was clear that the magnitude of the magnetic field strength vector and the magnetic power loss along the direction of about 135° increased by applying the shear stress.
Nonlinear vibration of a post-buckled giant-magnetostrictive thin film laminated beam
Authors: Gen Ge , Zhu ZhiWen , Xu Jia
Published: December 2018

One buckled simply supported giant magnetostrictive material (GMM) thin film laminated beam model subject to axial magnetic excitations is proposed. The magnetostrictive force is simplified as a harmonic excitation. Applying the Hamilton principle and Galerkin approach the model is expressed as a one dimensional vibrating model with parametrical excitation. The multi-scales method is used to obtain the approximation of the solution when the vibration is around the buckled position and the amplitude of the oscillation is small. With the help of the undermined fundamental frequency method and normal form theory the Melnikov approach is improved to calculate more precise threshold value of the amplitude of excitation leading to chaos. The numerical simulation shows the performance of the new Melnikov approach is much better than the traditional way.
Variation of the magnetic properties of the martensite phase of SUS304 steel due to tensile deformation
Authors: Kinoshita Katsuyuki , Nakazaki Ryo , Matsumoto Eiji
Published: December 2018

In order to be able to develop a deterioration sensor based on the inherent magnetic phase in type 304 stainless steel (SUS304 steel), the relationships between the magnetic properties of SUS304 steel and the martensite structure induced in it by tensile deformation were investigated using the electromagnetic impedance (EMI) method, optical microscopy, and the equivalent inclusion method. The results showed that the martensite fraction and internal stress had the greatest effect on the magnetic properties of SUS304 steel in the low tensile strain range. On the other hand, in the high tensile strain region, the changes in the shape and orientation of the martensite particles owing to tensile deformation had the most significant effect on the magnetic properties of SUS304 steel.
Pulsed eddy current detection of cracks in F/A-18 inner wing spar at large lift-off using modified principal component analysis
Authors: Horan Peter , Underhil Ross , Krause Thomas W.
Published: December 2018

Stress corrosion cracks may develop between fasteners in the aluminum inner wing spars of F/A-18 (CF188 Hornet) aircraft. These fasteners secure carbon-fibre/epoxy composite wing skin, of varying thickness (8 to 21 mm), to the spar. Inspection of the spar through the wing skin is required in order to avoid wing disassembly. A pulsed eddy current system that uses principal component analysis and discriminant analysis to identify cracks has been field tested at the USN North Island facility. The results show that the system can accurately identify cracks in real time throughout the wing. The method is far faster than X-ray radiography and, because it is very portable, can be readily deployed to second or first line facilities. Issues that need to be addressed to improve the performance of the system are identified and potential solutions are examined.
Partial CT for in situ bridge NDE with 950 keV/3.95 MeV X-band linac source
Authors: Wu Wenjing , Zhu Haitao , Jin Ming , Dobashi Katsuhiro , Fujiwara Takesi , Uesaka Mitsuru , Kusano Joichi , Nakamura Naoki , Tanabe Eiji , Sunaga Hideyuki , Otake Yoshie
Published: December 2018

Computed tomography system for in situ NDE of degradation bridges is under development, with portable 950 keV/3.95 MeV X-band linac as x-ray source. Collimator is adopted to reduce scattered X-ray noise and 3D model can be built from sectional images so that it becomes possible to evaluate mechanical characters of bridges referring to structural analysis with reduced stiffness. Furthermore, considering limitation of projection angle range during in situ scanning, reconstruction technique with incomplete projection data is studied with experimental data.
An optimum design of rotor slot shape of induction motor for electric vehicles using numerical techniques
Authors: Lee Woo Youl , Kim Yong Bae , Shin Pan Seok
Published: December 2018

A rotor slot shape of induction motor for electric vehicle is optimized by FEM with the numerical techniques. To optimize the rotor slot shape, two objective function and 3 variables are defined, and the optimization algorithm is developed. To verify the program, 4 poles 44 kW induction motor is modeled, simulated and analyzed by the program. The optimized rotor slot shape result makes reasonably good improvement to increase torque and efficiency of the motor performance.
A study on influence of plastic deformation on the global conductivity and permeability of carbon steel
Authors: Cai Wenlu , Chen Hong-En , Xie Shejuan , Li Yong , Chen Zhenmao , Uchimoto Tetsuya , Takagi Toshiyuki , Kensuke Yoshihara
Published: December 2018

Non-destructive evaluation (NDE) techniques are indispensable for inspection of damage in structures of carbon steel, which is widely used in many industries. In this paper, experimental and numerical studies were conducted to investigate the electromagnetic property variations of carbon steel Q195 due to plastic strain by using the 4-probe potential drop method and ECT aiming at NDE applications. A series of specimens were fabricated and uniform global plastic strains of different levels were introduced to the specimens by tensile testing. 4-probe potential drop measurements were carried out to obtain the conductivity information at first. It is found that the macro conductivity is not affected significantly by the plastic strain once taking into account the influence of the cross-sectional area reduction of the specimens. Combining the results of numerical analysis using a code of A_r formulation with the measured ECT signals, the permeability of specimens with various plastic damages was evaluated through inverse analysis. It is proved that the ECT signal change due to plastic damages is mainly caused by the variation of permeability, which gives a good possibility to evaluate the plastic damage with a magnetic NDE method.
Size adapted GMR arrays for the automated inspection of surface breaking cracks in roller bearings
Authors: Pelkner Matthias , Reimund Verena , Erthner Thomas , Kreutzbruck Marc
Published: December 2018

Their small size together with a remarkable field sensitivity are the most prominent features of present-day GMR sensors paving the way for various applications in automated non-destructive testing (NDT). This work presents a prototype for fast and automated magnetic testing of roller bearings. A local magnetization unit excites the magnetic field inside the bearing. As a result of a design study and the following wafer fabrication the probe was equipped with NDT-adapted GMR sensor arrays in which 48 elements measures the field response. The detection of artificial and 40 μm deep defects could be resolved with a SNR better than 20 dB. In addition, we report of first results of a POD (Probability of Detection) analysis using GMR sensors to investigate bearings with EDM (electronic discharge machining) notches having depths down to 10 μm. Finally, we estimate successfully the depth of a 57 μm notch from the measured data.
Using electrical impedance tomography to monitoring flood banks
Authors: Rymarczyk Tomasz
Published: December 2018

The electrical impedance tomography is a widely investigated problem with many applications in physical and biological sciences. A new nondestructive method of the flood embankment dampness was tested. The basic information about the built measuring system, including the prototype equipment is given. The setup was used to determine the dampness of the test flood blank on a specially built model. The forward problem solution (in the electrical impedance tomography) is solved by the determining potential distribution inside the region under given boundary conditions. The full information about region is considered, This problem is solved by Laplace's equation. The level set methods with the Chan-Vese model were applied in the inverse problem for the image reconstruction.
Optimal design of permanent magnet actuator for vacuum circuit breakers using response surface methodology
Authors: Ahn Hyun-Mo , Lee Jong-Deok , Lee Byuk-Jin , Hahn Sung-Chin
Published: December 2018

Recently, permanent magnetic actuator (P.M.A.) is widely used to drive the mechanism of vacuum circuit breaker (V.C.B.). This paper deals with the optimal design of P.M.A. for V.C.B. using the response surface method(R.S.M.). First, the dynamic characteristics of the initial P.M.A. model, such as the holding force, exciting current, and action complete time, are calculated by coupled electrical-mechanical problem based on finite element method (F.E.M.). In order to verify the validity of numerical results obtained from finite element analysis (F.E.A.), the calculated dynamic characteristics of the initial P.M.A. model are compared with no-load test results. Next, using the R.S.M., the initial P.M.A. model is optimized to improve the dynamic characteristics. Finally, in order to verify the validity of the P.M.A. model optimized by using the R.S.M., the dynamic characteristics of the optimized P.M.A. model are calculated by using F.E.A. and compared with those of the initial P.M.A. model.
EMAT simulations based on a two- dimensional FEM coupled electro- mechanical formulation
Authors: Garcia-Rodriguez Daniel , Mihalache Ovidiu , Ueda Masashi
Published: December 2018

This work presents the development of a new approach to EMAT finite element method (FEM) simulations by using a novel coupled electromagnetic-mechanical equation system. Validation is performed within the limits of the un-coupled equations using commercially available FEM codes. The advantages and drawbacks of the new method versus the traditional un-coupled approach are evaluated for various EMAT patterns. Numerical FEM analyses use a sparse direct solver with either Euler or Crank-Nicolson implicit time integration methods.
Statistical classification of contamination in glass insulators by reading its spectrum
Authors: Moura Emanuelle P. , Albert Bruno B. , Fontgalland Glauco
Published: December 2018

This paper proposes to use a statistical approach for classifying the contamination level of insulators used in high voltage transmission lines. This studied case considers the voltage applied on glass insulators used in a chain of six elements of a 69 kV power line. When submitted to high voltage, the insulators radiate radio frequency signals up to frequencies of some GHz. In this frequency range the signal can be detected using portable antennas, and then be applied to post processing. These received spectra are analyzed by statistical methods, mean and standard deviation, and the cross relation between them is used to classify the pollution level in insulators. To reduce complexity and cost a simple data processing using the mean and the standard deviation are used. Two types of glass insulators are considered: clean or polluted, and to cover the entire frequency range from 30 MHz to 1 GHz two types of antennas were needed. The results obtained with the mean and the standard deviation show that the first 100 MHz bandwidth can be used for statistical of the insulator pollution level.
Characteristics analysis of magnetic force distribution in double-sided AFPM machine with unbalanced structure
Authors: Choi Dawoon , Jung Whansung , Cho Yunhyun
Published: December 2018

The axial flux permanent magnet (AFPM) machine is widely used in many applications due to its advantages. But the conventional AFPM machine has the major problem such as the deformation and unbalanced air gap occurred because of the large magnetic attraction force between the rotor and the stator. For these problems, the magnetic attraction force must be accuractly calculated in the process of the design step of the mechanical parts. Thus, this paper proposes the analysis method to compute the magnetic attraction force of AFPM machine considering a unbalanced rotor structure. The quasi 3D model with a different air gap condition is introduced to analyze the magnetic flux density and the magnetic attraction force due to the eccentricity of rotor structure. To validate the proposed analysis process with the quasi 3D model, 3D FEM analysis is performed to compare the results. As results, the proposed analysis results was obtained the similar results to 3D FEM analysis results. The proposed method is applied and estimated to the 130 kW AFPM generator.
Computation of transient electromagnetic force on power transformer windings by inrush current
Authors: Ahn Hyun-Mo , Kim Joong-Kyoung , Ha Jung-Woo , Kwak Ki-Yeol , Oh Yeon-Ho , Hahn Sung-Chin
Published: December 2018

In general, a lot of computing time is needed to analyze the transient characteristics of a power transformer with complex geometry by field-circuit coupling method. This paper proposed a modified 2-D model and an efficient field-circuit coupling technique of a power transformer in order to reduce the computing time. To analyze the transient electromagnetic force acting on each disk of transformer windings, we made 2-D axisymmetric model. First, the transient current equation considering the residual flux was solved to get the inrush current. Next, the transient electromagnetic force due to the inrush current is obtained by applying finite element method (F.E.M.) to the modified 2-D model. The proposed method will be useful for the structure design of the power transformers.
2 DOF non-contact magnetic suspension system: A feasibility study
Authors: Oka Koichi , Okazaki Tomohiro , Morimitsu Toshiyuki
Published: December 2018

This paper describes 2 types of 2 DOF magnetic suspension systems which suspend two iron balls or an iron stick type object. Both suspension system controls 2 DOF of suspended object(s). The magnetic suspension forces are controlled by a generator of magnetomotive force. This suspension system must control two degrees of freedom without mechanical contacts. In iron stick suspension system, a vertical displacement and a horizontal rotation of the object should be controlled. This paper proves the feasibility of these noncontact suspension systems. A theoretical analysis will be done on the model of these suspension systems and numerical simulations carried out for confirmation of performances.
Temperature field distribution optimization of MFH for cancer therapy
Authors: Hu Guanzhong , Li Yuling , Yang Shiyou , Chu Jianglong , Bai Yanan , Huang Jin
Published: December 2018

The magnetic nanoparticles in AC alternating magnetic fields will produce a large amount of heats due to the Néer relaxation. Magnetic Fluid Hyperthermia (MFH), based on this mechanism, offers a new breakthrough and has a promising potential in tumor treatments. The temperature field distribution in the treatment and neighbor regions has a significant effect on the therapeutic result. Therefore, it is essential to control the temperature in the treatment region in a proper range (42°C∼90°C) while to guarantee a sharp gradient in the boundary of the treatment and normal regions. This study provides an automatic shape design methodology using the Finite Element Analysis (FEA) of the electromagnetic-temperature Coupled Field (CF) and a multi-objective Particle Swarm Optimization (MOPSO), to realize sufficient uniformities in the temperature field distribution while to ensure the enough temperature gradient in the cancer boundary.
Embedded PM magnetic-geared generator
Authors: Oshiumi Tsubasa , Niguchi Noboru , Hirata Katsuhiro
Published: December 2018

This paper proposes a new magnetic-geared generator, which has a novel permanent magnet arrangement whereby the permanent magnets are embedded into the high-speed rotor and the stator slots, for direct-drive wind power generation systems. The operational principle is described and the performance is verified by using finite element analysis.
Measurement of human scratch behavior using compact microphone
Authors: Okuyama Takeshi , Hatakeyama Kazuki , Tanaka Mami
Published: December 2018

This study describes the development of a sensor system for measuring human scratching motion. In order to measure the scratching motion, we focus on the mechanical vibration between the nail and the skin that is scratched. Scratching sounds, induced by the vibration, change according to the scratching intensity or the skin condition. Therefore, the information on the scratching sounds can help us to evaluate the characteristics of scratching. In this study, a nail-mounted compact microphone sensor for measuring human scratching sounds is designed and fabricated. First, the ability of the proposed sensor to measure scratching sounds is investigated. The feasibility of this sensor has been verified. Next, the power spectrum density is calculated from the sensor output to investigate the characteristics of the scratching sounds according to the scratching intensity. It was found that frequency components increased with an increase in the contact force during scratching. The results suggest that it is possible to evaluate the scratching intensity by using the proposed sensor system.
Optimization of electromagnetic wave focusing in heterogeneous biological tissue model
Authors: Faktorová Dagmar , Isteníková Katarína
Published: December 2018

The paper presents some optimization approaches to the electromagnetic wave focusing in heterogeneous biological tissue model. The model of human arm was used for investigation. The possibility of focusing of electromagnetic wave optimisation is strongly connected with investigation of electromagnetic wave propagation through complicated heterogeneous biological structure. Firstly we concentrated on the influence of particular structures thickness on scattering parameters value which gives us information about transmission and reflection of electromagnetic wave on interfaces of structures which differ by dielectric parameters. The next simulation showed the influence of water bolus placed on the arm model surface on values of SAR and consequently the possibility to avoid the overheating of upper region of arm model in the process of microwave hyperthermia. The next step connected with possible optimisation of electromagnetic wave focusing showed the influence of metamaterial structure placed in the front of microwave patch antenna used in role of microwave hyperthermia applicator on the electromagnetic wave focusing. The simulations were done for various numbers of metamaterial structures and various distances from arm model. Finally we simulated the focusing accuracy in the case when the combination of water bolus with metamaterial structure was used.
A new approach to the non-iteration conversion method for dielectric constant assessment
Authors: Faktorová Dagmar
Published: December 2018

The paper deals with some methods for relative permittivity of dielectric materials measurement and with the relevant techniques. In addition to current methods of measurement evaluation on vector network analyser our new approach gives also information about possibility of the use of classical methods for evaluation of application at vector network analyser as a faster source of basis for computations. In the paper also an attention to a situation is paid when it is problematical to determine the unknown permittivity of solid material by usual methods.
Effect of residual stress on magnetic properties of motor cores
Authors: Kai Yuichiro , Tsuchida Yuji , Todaka Takashi , Enokizono Masato
Published: December 2018

The magnetic properties of electrical steel sheet deteriorates due to residual stress, which occurs during the manufacturing process. Therefore, it is important to know the relationship between the magnetic property and the residual stress in order to utilize electrical steel sheets effectively. This paper presents the effect of residual stress on the magnetic properties of motor cores in a rotating machine. First, the local residual stress distribution of the motor core is measured using an X-ray stress measurement system. Next, the magnetic properties of the motor cores for the different residual stress distributions are measured using a single sheet tester. Based on these results, the maximum permeability and magnetic power loss differed depending on the sample, each of which had a different residual stress. In addition, we attempt to measure the inductance of the motor core in order to easily evaluate the magnetic property. The difference in the inductance of each sample was obtained based on the excitation voltage and frequency measured using an LCR meter. It is very useful to evaluate the inductance in order to easily determinine the difference in the residual stress.
Characteristics analysis of a haptic device using a 2-DOF linear oscillatory actuator
Authors: Kono Yoshinori , Yoshimoto Takamichi , Hirata Katsuhiro
Published: December 2018

Haptic devices using asymmetric drive have been attracting attention. We have been studying 2-DOF haptic devices using a 2-DOF oscillatory actuator that can independently output asymmetric acceleration waveforms in 2 axes. This paper presents a new 2-Degree-of-freedom (DOF) linear oscillatory actuator. First, its static characteristics are computed by 3-D finite element method (FEM). Then, the dynamic characteristics of the actuator under asymmetric acceleration drive are clarified through FEM analysis and finally compared with measurements on a prototype.
The study on the design parameters and losses of copper die-casting induction motor for high speed
Authors: Han Pil-Wan , Kim Dong-Jun , Chun Yon-Do , Choi Jae-Hak , Seo Un-Jae , Koo Dae-Hyun
Published: December 2018

High speed induction motors have the different design parameters and loss distribution compared with line start induction motor because of various load conditions and inverter-fed supply voltage. Especially harmonic losses and mechanical losses must be considered severely. In order to check the variation of the design parameters in inverter-fed induction motor, these values are compared with those of line start induction motor (sinusoidal supply voltage) at same rated output power. The experimental results are verified through testing prototype of two types of 30 kW induction motor for loss analysis. The amount of harmonic loss is confirmed by calculating the loss differences between operating 4.5 kW induction motor from sinusoidal and inverter-fed supply voltage.
Selected Papers from ISEF-2013 Conference
Authors: Di Barba Paolo , Wiak Słwomir
Published: December 2018

Preface to the Selected Papers from ISEF-2013 special issue.
Cogging torque minimisation of PM synchronous motor using genetic algorithm
Authors: Cvetkovski Goga , Petkovska Lidija
Published: December 2018

The minimization of the torque ripple in permanent magnet synchronous motors (PMSM) is generally achieved by a special motor design which in the design process involves a variation of many geometrical motor parameters. In this paper a new approach is introduced where genetic algorithm is used as an optimization tool where the maximum value of the cogging torque is used as an objective function. Therefore a proper mathematical presentation of the cogging torque for the analyzed synchronous motor is developed. Finally the initial motor and the optimized motor model are modeled in FEMM software which is based on finite element method. The cogging torque is analytically and numerically calculated and the results for both models are presented.
Progressive eddy current modeling via a finite element subproblem method
Authors: Dular Patrick , Péron Victor , Krähenbühl Laurent , Geuzaine Christophe
Published: December 2018

The modeling of eddy currents in conductors is split into a sequence of progressive finite element subproblems. The source fields generated by the inductors alone are calculated at first via either the Biot-Savart law or finite elements. The associated reaction fields for each added conductive region, and in return for the source regions themselves when massive, are then calculated with finite element models, possibly with initial perfect conductor and/or impedance boundary conditions to be further corrected. The resulting subproblem method allows efficient solving of parameterized analyses thanks to a proper mesh for each subproblem and the reuse of previous solutions to be locally corrected.
Contactless conveyance of conductive rod by rotating the radial electrodynamic wheel with a spiral structure
Authors: Jung Kwang Suk
Published: December 2018

When a spiral-shaped, radial electrodynamic wheel with an axial pitch is rotated around a conductive rod, the magnetic field produced by the wheel can travel in the axial direction as well as in the circumferential direction of the wheel. Therefore, the rotating spiral wheel produces three-axial magnetic forces: a torque in the circumferential direction, a thrust force in the axial direction, and a repulsive force in the radial direction of the rod. These forces can be used effectively in the contact-free conveyance of the conductive rod. In this paper, the magnetic forces produced by the spiral wheel are modeled theoretically, and the model is verified by FEM and experiment. And, desirable design specifications of the wheel are proposed by analyzing the influences of the pitch angle and the number of permanent magnets that govern the characteristics of the spiral wheel. However, the only parameter that influences the forces generated by the wheel is the rotation speed of the wheel. So, a control algorithm that varies only the rotating speed of the wheel to convey the conductive rod is proposed, and its feasibility is verified by application to a constructed set-up.
Bounds on the average of total scattering cross section of random cylinder
Authors: Ashraf Muhammad A. , Rizvi Azhar A.
Published: December 2018

Total scattering cross section (σ _T ) of a PEC cylindrical scatterer is a function of it's scattering amplitude and is closely related to scatterer's cross section. It is difficult to determineσ _T analytically for arbitrary cross sections of scatterer, especially for random cross sections. Defining some bounds on the value of σ _T is therefore very helpful in its estimation. In this paper, σ _T of canonical shaped objects is used to define bounds on σ _T of random cylinder. The geometrical parameters of canonical scatterers are obtained from the geometric parameters of the random cylinder. A formulation is also developed to approximate the value of σ _T from its bounding values. This work therefore, helps to predict theσ _T of a random cylinder from its geometrical parameters, without solving an electromagnetic boundary value problem.
Effects of free edge on the vibration characteristics of a contoured, beveled quartz resonator
Authors: Yang J.S. , Tiersten H.F.
Published: December 2018

The equation for transversely varying thickness modes in doubly-rotated quartz resonators is applied in the analysis of the vibrations of contoured resonators with beveled cylindrical edges. The treatment in this work differs from that of earlier work in that the dominant condition at the edge of the resonator is satisfied and the approximation made earlier in the beveled annulus is not made here where the solution is exact. A procedure for the analytical determination of the required diameter for a good resonator is identified and calculated results are compared with those of the earlier work.
Effect of unbalanced supply on dynamic eccentricity fault diagnosis in induction motor
Authors: Kaikaa M.Y.
Published: December 2018

In this paper, a precise approach is proposed to detect DE in induction motors under unbalanced voltages. To achieve this goal, one essential problem is dealt with: The frequencies of the components caused by the DE in the stator current spectrum are similar to some of the frequencies introduced by the unbalanced voltages. Thus, the present paper attempts to explain, analytically, experimentally and by simulation, the generation process of all frequency components that are a function of the unbalanced voltages and the DE. For that reason, a detailed analytical study for three-phase induction motor working with DE is performed. First, an analytical expression for the mutual inductances between stator phases and rotor loops under DE is derived using mixture of winding function and Fourier series approach. Then, both theoretical and simulation studies are presented in order to show how the stator current is influenced by the simultaneous presence of DE eccentricity and unbalance supply voltages. Finally, experimental results have been presented to validate the analytical and simulation results.
3-D numerical investigation of natural convection in a tilted cylindrical annulus containing molten potassium and controlling it using various magnetic fields
Authors: Afrand Masoud , Farahat Said , Nezhad Alireza Hossein , Ali Sheikhzadeh Ghanbar , Sarhaddi Faramarz
Published: December 2018

In the present paper, numerical analysis of an electrically conducting fluid under the influence of a magnetic field in an inclined cylindrical annulus is presented. The inner and outer walls are kept at constant temperatures, and the top and bottom walls are assumed to be adiabatic. The numerical method used to solve the nonlinear governing equations of the problem is finite volume scheme. The computational results reveal that the effect of transverse magnetic field is more significant than that of the axial magnetic field on the average Nusselt number. Also, it is found that when the magnetic field is perpendicular to the axis of annulus, the average Nusselt number decreases from 7.8 to 4.7 with an increase in Ha from 0 to 60.
Calorimetric measurement and modelling of iron losses in a Silicon Iron current sensor
Authors: Dhahbi Hakim , Gallot-Lavallee Olivier , Kedous-Lebouc Afef , Mas Patrick , Geoffroy Olivier , Buffat Sebastien
Published: December 2018

In this paper, the magnetic losses of a supply current sensor dedicated to circuit breakers are investigated. Measurements were performed using an accurate calorimeter covering a measurement range of [1 mW; 10 W]. Several frequencies and voltages were tested. A model of the sensor’s core material (NO SiFe sheet M250-50A) was built with the Loss Surface (LS) dynamic hysteresis model and implemented in a 3D FEM computation tool. The sensor was simulated and iron losses were computed. Comparison between experiments and simulation shows a high concordance that leads to conclude about the reliability of the LS model.
The significance of the time constant of the rotor material employed in a dielectric motor
Authors: Mognaschi Ezio Roberto , Calderwood James Henry
Published: December 2018

An electrostatic motor has been designed and built, and its construction is described. It was capable of running either as an induction motor or as a synchronous motor, depending on the electrical characteristics of the rotor material. The critical factor determining which behaviour is exhibited appears to be the time constant of the rotor material. Analytical expressions are given for the mechanical torque developed when the machine is running in each mode. When mechanical torque was applied to the axle of the unenergised machine, it was observed that an ac emf appeared at the terminals and the machine was therefore operating as a generator.
A non-uniform model for alternating current field measurement of fatigue cracks in metals
Authors: Zhou Jianwei , Lugg Martin C. , Collins Roy
Published: December 2018

The ACFM technique has been proved to be an extremely practical NDE method for crack detection and sizing. Its original mathematical model is based on a uniform interrogating surface current field. In this paper, the theoretical aspects of the ACFM technique are re-examined. The thin-skin theory of electromagnetic perturbation due to a surface-breaking crack has now been generalised to allow non-uniform interrogating current fields and has then been combined with the theory of electromagnetic induction in a half-space to produce a non-uniform ACFM model. More realistic simulations of many types of ACFM probes are obtained from the new theoretical model.
Magnetic fields of cylindrical coils
Authors: Yang Z.J. , Hull J.R.
Published: December 2018

Using mathematical transforms, we present an improved method to compute magnetic fields from current coils with cylindrical symmetry. For some typical model systems, the closed-forms are given for the convenience of use in engineering design. The method we present can generally be used to calculate magnetic field distributions for practical engineering designs with greater efficiency than conventional methods. This method can potentially be applied to other physical problems, such as deriving gravitational potential.