bluuebunny/crossref_metadata_2025 huggingface dataset:
A new bearing structure for a single-axis controlled repulsive type magnetic bearing with motor function
Authors: Ohji Takahisa , Sugiura Ken , Amei Kenji , Sakui Masaaki
Published: December 2018

This paper reports novel magnetic bearing structures with the function of a bearingless motor (BeLM) and a repulsive type magnetic bearing(RTMB). The structures consist of circular arc permanent magnets for field poles and cylindrical permanent magnets for magnetic bearings. Two types of permanent magnet configurations suitable for an ultra high-speed motor are proposed in this paper. From measurement results of magnetic flux density distributions, it was verified that a magnetic pole composition using Halbach array leads to good coexistence of both BeLM and RTMB.
Magnetic property change of type 304 stainless steel due to accumulation of fatigue damage at elevated temperature
Authors: Takaya Shigeru , Nagae Yuji
Published: December 2018

Developing a nondestructive method for estimating material degradation before crack initiation will contribute to improvement of safety and economical efficiency of fast breeder reactor plants. In this study, fatigue tests on type 304 stainless steel at 923 K, measurements of magnetic flux density, and microscopy studies were conducted. As a result, it was shown that the maximum value of variation of magnetic flux density during the fatigue tests increased linearly in relation to the number of loading cycles and this magnetic property change was due to phase transformation.
Analysis of 3D electromagnetic field for three-phase low voltage and heavy current busbar bridge system
Authors: Sha Xu , Xianlong Jin , Feng Pang , Jie Shen
Published: December 2018

In this paper, the three-dimensional finite element model of a low voltage and heavy current three-phase busbar bridge system is established. The edge element is used to discretize the finite element equations of the electromagnetic field. The main characteristics of magnetic flux density and electromagnetic force in the system are obtained. Through the comparison between calculation results and measured ones, the reliability of the calculation is validated. The influence of the operating current, different arrangements of three-phase busbars, space between each phase busbar and frequency on electro-magnetic parameters, especially magnetic flux density and electromagnetic force, are also studied.
Deformable mirror near field microwave imaging
Authors: Arunachalam Kavitha , Udpa Lalita , Udpa Satish S.
Published: December 2018

The concept of using adaptive optics based deformable mirror for near field microwave imaging of penetrable objects is presented in this paper. The deformable mirror microwave tomography technique proposed for inverse scattering applications relies on the use of an adaptive mirror to steer the electromagnetic (EM) field for multi-view irradiation of an unknown dielectric object using a fixed EM source. The deformable mirror tomography method offers higher degrees of freedom in that a large number of field measurements can be recorded by adaptively changing the mirror shape during data acquisition. In this paper, the potential of a deformable mirror to yield useful field measurements for reliable permittivity reconstruction is investigated via computer simulations for TM ^z polarization. The investigation also includes the robustness of the novel imaging technique in recovering the unknown permittivity distribution in the presence of noise.
Optimization of Hybrid Solar Wind Power Systems
Authors: Dilettoso Emanuele , Gagliano Salvina , Salerno Nunzio , Tina Giuseppe Marco
Published: December 2018

The paper proposes a new method for the optimized design of grid-connected Hybrid Solar Wind Power Systems (HSWPS). The optimization objectives are maximization of the economic efficiency and performance of the system. Evaluation of the objectives, related to assessment of the long-term performance of the system, is performed by means of a probabilistic model. Two different stochastic algorithms proved to be suitable for the optimization: Particle Swarm Optimization and Genetic Algorithms. The proposed strategy was applied to real systems, obtaining good solutions at low computational costs.
The IX Workshop on Optimization and Inverse Problems in Electromagnetism, OIPE_Sorrento
Authors: Formisano Alessandro , Martone Raffaele
Published: December 2018

Preface to the IXth Workshop on Optimization and Inverse Problems in Electromagnetism, OIPE_Sorrento special issue.
Pulsed eddy current thickness measurement of conductive layers over ferromagnetic substrates
Authors: Lefebvre J.H.V. , Mandache C.
Published: December 2018

The focus of this study is the behaviour of the lift-off point of intersection (LOI) under various test conditions: lift-off, thickness and conductivity of metallic layers with and without a ferromagnetic substrate. The pulsed eddy current (PEC) signal response is analyzed and a lift-off independent method to measure the thickness of conductive layers over ferromagnetic substrates is presented. This approach is tested by scanning specimens with varying lift-off and conductive layer thickness. The test articles have different substrate permeabilities, but identical lift-off and conductive layer conditions. The results demonstrate that the LOI feature can be used to measure the thickness of conductive layers over ferromagnetic substrates.
Piezoelectric cylinder under voltage and axial loading
Authors: Senjuntichai T. , Kaewjuea W. , Rajapakse R.K.N.D.
Published: December 2018

This paper considers quasi-static linear response of a solid piezoelectric cylinder due to electric voltage and mechanical loading applied at the ends. A recently developed analytical general solution for an annular cylinder of finite length is used to analyze this complex mixed-boundary value problem. The general solution for electroelastic field and the applied loading are expressed in terms of Fourier-Bessel infinite series. Both flexible electrodes in smooth contact with and rigid electrodes bonded to the cylinder ends are considered. The problem is formulated by dividing the electrode contact area into several annular rings and developing a flexibility equation system based on a set of influence functions to satisfy the mixed-boundary conditions at the cylinder ends. The present approach allows consideration of a cylinder under a variety of electromechanical loading conditions. Accuracy of the present scheme is confirmed by comparing with the existing solutions for the limiting case of an elastic cylinder. Selected numerical results for different cylinder length-radius ratios, electrode dimensions, materials and electric voltage and mechanical loads are presented to demonstrate the coupled electromechanical behavior of a cylinder.
Experimental and numerical analysis of the coupling mechanism of HF antenna located on shipboard
Authors: Turetken Bahattin , Ustuner Fatih , Demirel Ekrem , Baran Ersan
Published: December 2018

In this paper, the coupling analysis of HF antennas mounted on a ship is presented. The method of Moments (MoM) is used to calculate the inter antenna coupling in 1.6–30 MHz frequency range. Numerical results with MoM are performed and the reliability of these methods is discussed according to the measurement results. The coupling measurements were acquired on 1:50 scale model of the shipboard.
A point heat source on the apex of a transversely isotropic magneto-electro-thermo-elastic cone
Authors: Hou Peng-Fei , Luo Wei , Leung Andrew Y.T.
Published: December 2018

We use the compact mono-harmonic general solutions of transversely isotropic magneto-electro-thermo-elastic materials to construct the three-dimensional solutions of a steady point heat source on the apex of a transversely isotropic magneto-electro-thermo-elastic cone by five newly introduced mono-harmonic functions. All components of coupled field are expressed in terms of elementary functions and are convenient to use. When the apex angle 2α equals to π, the solutions reduce to those of the semi-infinite body problem. Numerical results are given graphically by contours.
Morphological instability of a stressed elastic conducting cylinder – effect of magnetomechanical interaction
Authors: Yang Fuqian , Song Wei
Published: December 2018

The surface evolution of an elastic conducting cylinder carrying electric current was analyzed by considering the effect of magnetomechanical interaction and using the linear perturbation analysis. The driving force controlling the surface growth was the gradient of the chemical potential, consisting of the contributions of elastic energy, electromagnetic energy and surface energy. A general expression of the dispersion relation was obtained for describing the morphological evolution of the conducting cylinder subjected to self-induced magnetic field. It was found that the magnetomechanical interaction can enhance or inhibit the morphological instability of the elastic conducting cylinder when subjected to a far-field tensile stress. Such analysis might be of importance in understanding the surface evolution of nano-rods and nano-wires when carrying electric current.
Improved performance of the electromagnetic fuel injector solenoid actuator using a modelling approach
Authors: Cvetkovic Dean , Cosic Irena , Subic Aleksandar
Published: December 2018

The aim of this investigation was to develop a specific modelling approach capable of reducing the size of the fuel injector solenoid device while improving its response time and attraction force. Several developed modelling and simulation procedures have focused on various aspects of solenoid component modifications in order to develop an evolution process of miniaturising a fuel injector solenoid, using the latest finite element method(FEM) tool software. The specific factors that influenced the optimum operation of the fuel injector solenoid were the geometrical shape of individual solenoid components, material properties, air-gap constraints, boundary conditions, current source conditions, mass constants, and damping coefficients of the plunger. The attraction force distribution in the main air-gap was directly influenced by the taper angle of the 2D and 3D plunger pole faces, plunger length and the permanent magnetism. The precise definition of the electro-mechanical motion of plunger was of enormous importance in reducing the fuel injector solenoid response time, closely related to stroke and mass of the plunger, spring characteristics, motion and rebound of the plunger. Using the developed approach, the initial size of the fuel injector has been reduced by 35%, the attraction force increased by 26% and the response time reduced by 76%. However, by frequently repeating the design trials and conducting a thorough experimental investigation, the final minimum response time was achieved by the virtual rebound delay model. The reduction in response time from the 'optimal' experimental to virtual model was by 35%. The simplicity and effectiveness of the developed methods, allowed for quick and accurate evaluation.
On the interaction between the harvesting structure and the storage circuit of a piezoelectric energy harvester
Authors: Hu Yuantai , Hu Ting , Jiang Qing
Published: December 2018

The interaction between a harvesting structure and a storage circuit is modeled using a full-bridge rectifier. In order to focus on the challenges associated with modeling the intrinsic nonlinearity of the rectifier, the authors have considered a piezoelectric plate in the thickness-stretch mode of oscillation and have represented the storage circuit by a simple LRC circuit in this first attempt. It is found that the primary performance of such a model energy harvester can be characterized by two non-dimensional parameters, i.e., the non-dimensional aspect ratio of the piezoelectric plate and the non-dimensional inductance of the LRC circuit, and that the power density of this model harvester can be optimized by adjusting these two parameters properly. Specifically, for each fixed non-dimensional aspect ratio there exists an optimal non-dimensional inductance, at which the power density is maximized, and conversely, for each fixed non-dimensional inductance there is an optimal non-dimensional aspect ratio, leading to a maximum of the power density when the volume of the plate is kept constant. The analysis for this simplified model piezoelectric harvester, though not realistic, provides a framework for further development on design guidelines for piezoelectric energy harvesters of optimal performance.
FEM-3D electromagnetic field analysis coupled with genetic algorithm for measurement uncertainties estimation and optimal design of an instrument transformer
Authors: Cundeva-Blajer Marija , Arsov Ljupco
Published: December 2018

In the paper an advanced CAD (computer aided design) methodology for measurement uncertainties estimation of a combined current-voltage instrument transformer (CCVIT) will be presented. The metrological parameters of the CCVIT are influenced by many variables, mostly introduced by the non-linearity of the very complex CCVIT electromagnetic system. The electromagnetic field distribution in the CCVIT 3D domain will be determined by using an original program package FEM-3D (finite element method) developed at the Faculty of Electrical Engineering and Information Technologies (FEIT)-Skopje. The FEM results will be used for further metrological optimal design of the CCVIT by using the genetic algorithm. The FEM-3D estimated CCVIT metrological uncertainties will be experimentally verified through actual test results recorded in a laboratory.
Automated follicle segmentation in ultrasound scans of bovine ovaries
Authors: VanderLaan Donald J. , Khurshid Khawar , Ireland James J. , Jimenez-Krassel Fermin , McGough Robert J.
Published: December 2018

Important reproductive information can be determined by analyzing the follicles in an ultrasound scan of the ovary. The currently used process requires an expert to manually mark and measure the size of the follicles. Manual analysis is time-consuming and often conflicting. A robust computer assisted approach to automatically detect and quantify follicles would improve both the efficiency and accuracy of the process. The multi-step algorithm presented involves coarse ovarian segmentation, follicle detection, and post processing using level sets to automatically determine follicle boundaries. In comparison with expert evaluations, experiments on bovine ovarian images show encouraging results. The algorithm correctly detected approximately 65% of the ovarian follicles.
Wideband notched compact UWB antenna
Authors: Kim Cheol Bok , Lim Jung Sup , Jang Jae Sam , Jung Young Ho , Lee Ho Sang , Lee Mun Soo
Published: December 2018

In this paper, a novel wideband frequency notched compact UWB antenna is designed to satisfy two licensed UWB frequency bands(3.1∼4.8 GHz, 7.1∼10.6 GHz). The notched wide bandwidth (4.8∼7.1 GHz) can be realized by inserting a pair of the inverted-L shaped slits in the fan-type arms of the coupled sectorial loop antenna(CSLA) and optimizing the positions and the length of the L-shaped slits to avoid the interferences with WLAN, GPS and so on. The performances of the designed UWB antenna are evaluated to inspect the fitness for the UWB communication services in the frequency and the time domain.
A small size dual-mode patch filter
Authors: Sheta Abdel Fattah
Published: December 2018

A small size dual-mode square patch resonator with slots etched in symmetrical shape is proposed. The filter response is obtained by exciting the degenerate modes and the first higher order mode of the proposed resonator through asymmetrical feeding. Area saving more than 80% with respect to the conventional degenerate dual-mode square patch filter and more than 20% with respect to the non-degenerate dual-mode patch filter can be achieved. Beside its compact size, the fractional bandwidth of the proposed structure can be reduced to half of the non-degenerate dual-mode filter; hence, more design flexibility. A bandpass filter is designed at 1.74 GHz with 6.9% fractional bandwidth on FR4 material with 4.2 dielectric constant and 0.78 mm thickness. Simulations are performed using full wave IE3D simulator. Simulations agree well with the experimental results.
Wavelet transform and neural network based 3D defect characterization using magnetic flux leakage
Authors: Joshi Ameet
Published: December 2018

Magnetic flux leakage (MFL) technique is commonly used for inspection of gas transmission pipelines. MFL signal is used to identify and characterize defects in the pipeline by estimating their length, width and depth (LWD). Knowledge of LWD alone is highly inaccurate and coarse compared to actual 3D geometry of the defect for predicting the maximum allowable operating pressure (MAOP) of the pipe. However, the inverse problem associated with prediction of 3D geometry is not only ill conditioned, but also involves complex numerical computation. As a result, little research has been done in this area. Author has published two different methods of dealing with this problem in collaboration with fellow researchers. This paper reviews the two approaches for estimating 3D depth profile of a defect from the corresponding MFL signal based on radial basis function neural network (RBFNN) and discrete wavelet transform (DWT).
Study of 3D image reconstruction using EMAT
Authors: Nishimura Yoshihiro , Sasamoto Akira , Suzuki Takayuki
Published: December 2018

UT scanner must have the sampling intervals and a beam spot size smaller than potential flaws in materials in order to be able to detect them. If material longer than 1m must be tested with a pitch of 1mm, more than 1000 scan lines are needed to detect flaws, and the material cannnot be examined in common production lines. The number of horizontal scanning lines must be decreased to reduce testing time. Alternatively, the scanning speed must be increased. This study performs propagation analysis of an acoustic wave emitted from a probe and presents methods and the formulas to reconstruct 3D image of flaws in the sample with fewer horizontal scanning lines.
An effective robust genetic algorithm based on reduced evaluation
Authors: Maruyama Takayuki , Igarashi Hajime
Published: December 2018

Robust optimization searches for optimal solutions which remain feasible under the effect of uncertainties. The conventional robust optimization, however, often requires great computational cost to find robust solutions. This paper introduces a novel robust optimization method based on genetic algorithm. In this method, individuals with "good" performance are selected and tested for their robustness for reduction of computational time. It is shown that the present method works in shorter time in comparison with the conventional robust optimization.
Low driving energy engine valve mechanism using permanent-electromagnet and conical spring
Authors: Nagaya Kosuke , Kobayashi Kazuya , Nenoi Masaomi , Hosokawa Yuhki , Murakami Iwanori
Published: December 2018

A new type valve system using a conical spring and an permanent-electromagnetic actuator was developed. The system uses a conical spring whose spring constant is low in small valve displacement, but increases with the displacement of the valve due to its nonlinear property. The system has a permanent-electromagnet which compresses the valve spring under electromagnetic control. The valve system is used without electric current in low cam speeds. Therefore, driving energy is small in low cam speeds because of spring constant being small. However, the jump and bounce phenomena occur in the high-speed cam rotation region. Those are suppressed by using a permanent-electromagnetic actuator that consists of two permanent magnets and an electromagnet. The actuator strengthens the restoration force of the spring by the electromagnetic repulsion force, and controls the jump phenomenon. Both analytical and experimental checks have been made for the proposed system. It was confirmed that, by using the system with the permanent-electromagnetic actuator, the jump and bounce phenomena were suppressed, and driving torques were also decreased.
The AMDE project: 3D volumetric anomalies reconstruction by eddy current testing
Authors: Calcagno S. , Cardelli E. , Faba A. , Formisano A. , Martone R. , Morabito F.C. , Papais M. , Pirani A. , Ricci M. , Specogna R. , Tamburrino A. , Trevisan F. , Versaci M. , Ventre S.
Published: December 2018

The AMDE project ("Applicazioni di Metodi per Diagnostica Elettromagnetica", in English "Applied Methods for Electromagnetic Evaluation") is an Italian two-years national granted research project on electromagnetic non-destructive evaluation. This project involves five different research units located in Italy, about twenty researchers and ten among Ph.D. students and post-doc. Here we focus on the contribution of the AMDE project to the reconstruction of 3D volumetric defects in metallic plates as those used in aeronautical and aerospace industry. In particular, in this work we propose an efficient numerical model for evaluating the field due to volumetric anomalies and an inversion method based on the Total Variation Regularization. Numerical examples confirm the capability of the proposed strategy to reconstruct 3D volumetric defects.
Characteristic analysis and design of a small size Rotary Ultrasonic Motor using the Cutting Method
Authors: Rho Jong-Seok , Lee Chang-Hwan , Jung Hyun-Kyo
Published: December 2018

The exact analysis of the piezoelectric motor has been impossible to the present time, although many researchers have proposed various kinds of analysis method for the piezoelectric motor using numerical method or analytic method. Also, the arranged design method has not been suggested for the Ultra-Sonic Motor (USM) taking the characteristic into account. In order to address these problems, we propose the analysis and design method for the USM using analytic method combined with numerical method. This method was named as the Cutting Method (CM) in this paper. The 8.5[mm] diameter Rotary Ultra-Sonic Motor (RUSM) is developed using the CM to verify the suggested method and for the demand of small actuators in industry. Finally, the proposed analysis and design method was validated by comparing its outcomes with the experimental data.

For the vibrator of the proposed 8.5[mm] diameter RUSM, four kinds of comb-tooth structures were prototyped in this research. Hence, the relation between the speed of the motor and the number of teeth is revealed for the first time. This is noteworthy because the tooth design method has not been proposed and because this result also verified the proposed CM.
Particle initiated discharges in gas insulated substations by random movement of particles in electromagnetic fields
Authors: Kumar G.V. Nagesh , Amarnath J. , Singh B.P. , Srivastava K.D.
Published: December 2018

Metallic particle contamination is one of the areas of insulation design that are considered critical. The management and control of particle contamination are crucial considerations as the industry moves forward to higher voltage GIS and long GITL designs using SF _{6} in some components. Free conducting particles may lower the corona onset and breakdown voltage of a GIS/GITL system considerably. Under an applied electric field a conducting particle acquires a charge and lifts off from its resting position on the conductor when the electromagnetic force from the field becomes equal to the gravity force. Metallic particles move randomly in a horizontally mounted GIS/GITL system due to the electrode surface roughness and particle irregularities. Under 50 Hz AC voltage, the particle can cross the gap at a sufficiently high voltage level. Monte Carlo simulation is carried out on a single phase GIS for determining the motion of free conducting particles in the presence of Electromagnetic field. The results have been presented and analyzed.
Simulation and optimization tool for high-frequency planar transformers based on 1D analytical modeling
Authors: Besri A. , Delinchant B. , Keradec J.P. , Sullivan C.R
Published: December 2018

For high frequency switch-mode power converters and supplies, planar transformers allow good performances to be reached. They suit very well to embedded power electronics applications, where size and weight matter. This paper presents a modeling, simulation, and sizing tool based on a 1D analytical model. This tool aims at helping designers describe, simulate, and know frequency behavior of planar wound components. As soon as all measurable impedances given as the tool outputs, device behavior becomes predictable. Due to its analytical nature, this tool is very fast and it can be driven by optimization software to reduce transformer losses and, finally, reduce cooling system weight.
Optimization energy management in buildings with neural networks
Authors: Foggia G. , Ha Pham T.T. , Warkozek G. , Wurtz F.
Published: December 2018

Neural networks algorithms are tested to replace an optimization module, for the energy management of a residential grid-connected PV system with storage. Multi-layer perceptrons are generic tools able to map non-linear relationships between inputs and outputs without knowing any information about the system model. This study shows multiple problems of the implementation of these techniques, despite their theoretical promising interests.
Non-invasive model-based localization of ventricular ectopic centers from multichannel ECG
Authors: Farina Dmytro , Dössel Olaf
Published: December 2018

Non-invasive localization of premature ventricular beat (PVB) foci is very important for medical treatment of numerous cardiac diseases. In this work a model-based method of reconstruction of ectopic center locations is investigated.

Within the scope of this method patient's multichannel ECG is used as a reference for optimization of an electrophysiological cardiac model. This model is based on the cellular automaton principle and utilizes anatomical data of the patient. Optimized are coordinates of the ectopic focus as well as excitation conduction velocity of ventricular myocardium. Initial values for these parameters are obtained by solving the linearized problem of electrocardiography in terms of activation times. Optimization is performed by minimization of discrepancy between the simulated and reference ECGs.

The aim of the current work is to estimate the quality of ectopic focus localization delivered by this method. Four sample ectopic beats have been simulated, with their foci located in different regions of the left ventricle. 1% Gaussian noise has been introduced into the resulting ECGs. In this way the "measured" ECG signals for this investigation have been obtained. Afterwards the origin of each ectopic beat has been reconstructed using the model-based approach. The method has demonstrated reliable localization of PVB foci, reconstruction errors have not exceeded 6.1 mm.
Hysteresis model identification by the Flock-of-Starlings Optimization
Authors: Riganti Fulginei Francesco , Salvini Alessandro
Published: December 2018

This paper presents the identification of the Jiles-Atherton and Preisach hysteresis models by means of a new heuristic: the Flock-of-Starlings Optimization (FSO). The FSO can be classified as an artificial life algorithm since it takes inspiration from the Particle Swarm Optimization (PSO) and from recent naturalistic observations on real flocks of common little European birds(starlings, Sturnus Vulgaris), performed by M. Ballerini et al. The one-to-one correspondence between the real flight of starlings searching food and the virtual flight of candidate solutions searching global optima is the core of the algorithm. Validations and comparisons with other heuristics have shown that the FSO gives good performances especially in those cases in which the solution space has a huge dimension. In fact, from the analysis of the obtained results by testing the FSO on hysteresis model identification, this heuristic has shown to be very attractive in comparison with other famous heuristics.
Analysis of scattering from buried object by using the geometrical optics
Authors: Abo-Seida Osama M. , Bishay Samira T. , El-Morabie Khaled M.
Published: December 2018

This paper is concerned with a theoretical solution to the problem of TE-Scattering radio waves by a buried object in a three-layered medium. The region of interest consists of three homogenous layered medium, the object of an inhomogeneous material with respect to its layer. With the aid of geometrical optics technique, this paper analyzes the influence of the buried object on the scattered magnetic field from the layered medium. Closed-form expressions for the far-field of a VMD, located above the ground surface, are obtained due to the buried object under the ground. This technique takes into consideration all the probabilities of plane waves under and above the ground to calculate the total reflection coefficient. The extra-scattered field due to the perturbation in the earth magnetic field has been obtained by solving Sommerfeld integrals (SI). The solution of SI has been based on the stationary-phase point method. The obtained results are compared with those mentioned in three- layered free buried objects.
The models of boundary conditions of electrodynamics on screens and environments with a non-uniform distribution
Authors: Jahanghir Tavakkoli
Published: December 2018

In the scientific literature, a great deal of attention is paid to building the mathematical models of electromagnetic fields in composite materials in a homogeneous environment which contains a large number of small heterogeneities of different shapes and material compositions [1].

Such models are reduced to solving boundary value problems for differential equations Maxwell with special kinds of particular boundary conditions on the structures of composite materials.

In this context one of the important structures is the spatial screen and environment which is to simulate the actual boundary conditions pairing them [2-6]. Such models provide a mathematical foundation for solving problems of electromagnetic-field shielding composite screens, that are used to solve problems of electromagnetic compatibility of technical equipment in radio and electronics.
Modeling and simulation of piezoelectric composite diaphragms for energy harvesting
Authors: Junwu Kan , Jinhao Qiu , Kehong Tang , Kongjun Zhu , Chenghui Shao
Published: December 2018

The energy conversion efficiency (ECE) of a piezoelectric generator can be denoted by its effective electromechanical coupling coefficient (EECC), which depends only on the geometry parameters with a certain boundary conditions. To obtain the optimal energy-harvesting device, the Raleigh Method was utilized to establish the analysis model of circular piezoelectric composite diaphragms. Simply supported and clamped boundary conditions were considered. The relationships between the performance parameters (EECC and natural frequency) and the structural parameters (diametric ratio β and thickness ratio α) of piezoelectric composite diaphragms were figured out. Given the correlative material parameters and boundary conditions, the performance parameters with the structural parameters as variables can be worked out. The simulation results show that the optimal structural parameters of a composite diaphragm in the case of the simply supported and clamped boundary conditions are different. A simply supported diaphragm generator tends to achieve higher effective electromechanical coupling coefficient and lower natural frequency, and is more suitable for the applications of energy harvesting.
Strain distribution monitoring wireless sensor network design and its evaluation research on aircraft wingbox
Authors: Wu Jian , Yuan Shenfang , Shang Yin , Wang Zilong
Published: December 2018

This paper presents a dedicated wireless sensor node for strain distribution monitoring, three functional modules are designed respectively, including sensor input unit, processing core, and wireless communication. The multi-channel strain gauge signal conditioning circuit is designed on the sensor input unit for multi-point strain distribution monitoring requirement and proved to be accurate and reliable. A miniature, lightweight, and shock-proof aluminum encapsulation is also designed especially for aerospace structural health monitoring (SHM) application. To verify the functionality of the designed wireless sensor node for SHM capability, a multi-point strain distribution monitoring system is developed on a aircraft carbon fiber reinforced plastic (CFRP) wing box. The strain gauges array is stuck to the inner surface of the CFRP wainscot and used to monitoring multi-point strain distribution. The reliable wireless sensor network is deployed adopting the designed wireless sensor nodes to gather, process, and transmit strain gauges signals and monitoring results. An embedding pattern matching method and a directed diffusion routing algorithm are developed to monitor the strain distribution successfully for the actual big CFRP wainscot.
Comparison of electromechanical characteristics of three phase induction motors with different pole and slot number combinations
Authors: Marčič Tine , Štumberger Bojan , Štumberger Gorazd , Hadiselimović Miralem , Zagradišnik Ivan
Published: December 2018

The comparison of electromechanical characteristics of a 4-pole and a 6-pole induction motor with 36 stator slots in combination with 28, 33, 34, 44 and 46 rotor slots is presented. A comparative analysis is performed by evaluating: the iron losses at no-load, the shapes of torque-slip curves, the shapes of torque per unit current vs. slip curves, and the efficiencies and over-temperatures in thermal equilibrium at rated load. The paper evidently shows that motors which exhibited low values of iron losses at no-load also exhibited superior line-starting performance, high values of torque per unit stator current and superior efficiency at rated load. Moreover, the paper shows the feasibility of using the same stator and rotor slot combination for a mid-size 4-pole and 6-pole induction motor.
A low and high frequency 3D model of metal foams shielding
Authors: Losito Onofrio , Cinquepalmi Luca
Published: December 2018

The growing use of metal foams in electromagnetic applications such as shielding applications, has paved the way to develop a simple analytical 3D model of metal foams, as discussed in this paper, considering the electromagnetic behaviour of an equivalent double wire-mesh screens model, separated by an air space. The good results encourages to design a metal foam shields with this model.
Electrically forced vibration of a rectangular piezoelectric plate of monoclinic crystals
Authors: Zhang C.L. , Chen W.Q. , Yang J.S.
Published: December 2018

We perform a theoretical analysis on electrically forced, coupled thickness-shear and flexural vibrations of rectangular piezoelectric plates of monoclinic crystals. Mindlin's first-order theory for piezoelectric plates is used, simplified by the flexure-twist approximation by Mindlin and Spencer. Two types of boundary conditions are considered. Trigonometric series solutions are obtained. The motional capacitance of the plates and its frequency dependence under a time-harmonic driving voltage, an important property when the plates are used as piezoelectric resonators, are calculated and examined from the series solutions for quartz and langasite plates.
The refined theory for a magnetoelastic body – II. Plane problems
Authors: Gao Yang , Xu Bai-Xiang
Published: December 2018

Without employing ad hoc stress or deformation assumptions, various two-dimensional equations and solutions for plane problems have been deduced systematically and directly from thick plate theory by using the general solution of magnetoelastic theory for the soft ferromagnetic elastic solids and the Lur'e method. These equations and solutions are used to construct the refined theory for the plane problems. In the case of homogeneous boundary conditions, the exact governing differential equations and solutions for the plate are derived, which consist of four governing differential equations. It can be noted that the refined theory is consistent with the decomposition theorem by Gregory. In the case of nonhomogeneous boundary conditions, the approximate governing differential equations and solutions for the plate are accurate up to the second-order terms. The correctness of the stress assumptions in the classic plane stress problems is revised. In two illustrative examples of plates, it is shown that the exact or accurate solutions can be obtained in use of the refined theory deduced herein.
Stress analysis of the field-assisted sintering: Electrothermal mechanical interaction
Authors: Yang Fuqian , An Linan
Published: December 2018

The field-assisted sintering techniques have the potential to produce bulk nanostructured materials from micron and submicron particles. Using the perturbation theory, the electrothermal, elastic deformation of a consolidated material has been analyzed. The material carries a uniform, axial electric current. Explicit expression of the temperature and stress fields has been obtained to the first order of approximation. The maximum temperature difference is proportional to the electric energy input to the material, and the average pressure applied to the pressing die is a nonlinear function of the electric current.
Electromagnetic shielding effect of chiral and typical materials
Authors: Oussaid Rachid
Published: December 2018

In this paper, we present a theoretical study of plane waves in chiral media. We are particularly interested in designing and analyzing chiral devices to quantify their shielding effectiveness as a function of frequency. The typical shielding materials used in this study are copper, aluminium and steel. We have also conducted a comparative study between these different types of materials. Due to chirality, there is magnetoelectric coupling. The electric and magnetic shielding effects are shown to be function of the three material parameters (ε, μ, κ). We found that, at normal incident angle, reflection occurs similar to that of isotropic medium. The cross-polarization effects caused by the chirality appear at oblique wave incidence.
Image reconstruction for 2D homogeneous dielectric cylinder using FDTD method and SSGA
Authors: Chien Wei , Huang Chung-Hsin , Chiu Chien-Ching , Li Ching-Lieh
Published: December 2018

This paper presents an image reconstruction approach for a 2-D homogeneous cylinder with arbitrary cross section in free space. The computational method combines the finite difference time domain (FDTD) method and non-uniform steady state genetic algorithm (NU-SSGA) to determine the shape and location of the scatterer with arbitrary shape. The subgirdding technique is implemented for modeling the shape of the cylinder more closely. The inverse problem is reformulated into an optimization problem and the global searching scheme NU-SSGA with closed cubic-spline is then employed to search the parameter space. A set of representative numerical results is presented for demonstrating that the proposed approach is able to efficiently reconstruct the electromagnetic properties of homogeneous dielectric scatterer even when the initial guess is far away from the exact one. In addition, the effects of Gaussian noises on imaging reconstruction are also investigated.
Design a new high intensity magnetic separator with permanent magnets for industrial applications
Authors: Arab-Tehrani Kambiz , Colteu Adrian , Rasoanarivo Ignace , Michel-Sargos Francois
Published: December 2018

This paper deals with a new high intensity magnetic separator with permanent magnets. We present a new system having little energy consumption. This model consists of compression springs, small motors, levers, and the slider rail which consists of iron blocks. The objective of this paper is to retrieve the granular ferromagnetic and paramagnetic minerals. We know that for magnetic separation systems with the permanent magnets, we can not cut immediately the magnetic field in the matrices for retrieving the magnetic granular minerals. In this model we have two different air-gaps; the first air-gap is for matrices installation and the second is used to change the reluctance in order to increase or decrease magnetic field in the magnetic circuit. In this system the carousel is fixed and the matrices can move. We will calculate the maximum magnetic force necessary in the second air-gap in order to send out the matrices after filling with magnetic minerals for washing and recovering materials. We will compare the theoretical results with the simulation results by COMSOL and FEMM4.
Magnetic actuator with ferrofluid and non-magnetic disc
Authors: Olaru R. , Petrescu C. , Hertanu R.
Published: December 2018

The paper studies an actuator based on magnetofluidic forces acting on a non-magnetic disc plunged into a ferrofluid that is exposed to a non-uniform magnetic field generated by magnetic inductor(s). The input output equations (force – current and displacement – current) that describe the behaviour of two types of actuators are established. The expression of the force generated on the nonmagnetic disc is determined analytically for the particular conditions imposed by the two actuator configurations: a) simple, with one magnetic inductor; b) differential, with two inductors. The derived relations enable a comparative study of the two types of actuators. The results show the superior performance of the differential actuator. The latter was tested as a current to displacement transducer in an electropneumatic converter.
Vector magnetic property for development of high density machines
Authors: Enokizono Masato
Published: December 2018

The national project of the development technology of next generation applied electromagnetic machinery was founded in Oita as Oita Prefecture Innovative JST (Japan Science and Technology Agency) Research Program. In this paper, outline of this project is introduced and the basic technology which is based on vector magnetic property is described. Especially the vector magnetic properties in high flux density level of 1.9 T are shown. As the example results, the dynamic vector magnetic characteristic is applied to the surface permanent magnet motor.
Capillary jet production of magnetic fluid by electromagnetic vibration
Authors: Sudo Seiichi , Wakuda Hirofumi , Asano Daisaku
Published: December 2018

The purpose of the present paper is to develop the generator of the capillary magnetic fluid jet. The experiments on magnetic fluid sloshing were conducted at first. Based on the results of experimental study on the fluid motions in a longitudinally vibrated tank with a permanent magnet, a magnetic fluid jet generator was developed. The generator is composed of NdFeB magnets, magnetic fluid, small circular cylindrical tank, and a coil. It is found experimentally that the magnetic fluid droplets and capillary jet are formed by the generator.
Domain wall displacement simulation for deformed micro magnetic clusters
Authors: Yamaguchi K. , Suzuki K. , Nittono O. , Takagi T.
Published: December 2018

Domain wall displacements were simulated using Monte Carlo method with a conventional crystal anisotropy for cylindrical and spherical micro magnetic clusters having a bcc crystal structure. The anisotropy properties of magnetization processes show qualitatively good correspondences with the experimental results for bcc iron. The simulations also demonstrate behaviors of their domain wall displacements and rotation magnetizations on the magnetization processes. Moreover the simulation was applied for a deformed cylindrical cluster elongated 1.01 times along the [010] direction and the result shows the domain wall displacement has a two steps process.
Study on applying the linear Halbach array to eddy current brake system
Authors: Wang Jiang-Bo , LI Yao-Hua , Yan Lu-Guang
Published: December 2018

Eddy current braking systems are used in order to avoid the limit of mechanical brake. The eddy current braking system with dc-excited magnet needs the power supply and has the consequent power losses. The braking system using permanent magnets can obtain high efficiency due to no power losses. The magnetic flux density of permanent magnet Halbach array is stronger than that of conventional permanent magnet array. Further more Halbach array is of one-sided flux structure and has self-shielding property, magnetic field of one side is enhanced and the other side is weakened. Hence applying linear Halbach array to eddy current brake system is studied. Analytical method is used to analyze the electromagnetic mechanism in eddy current brake and the braking force equation is deduced. An experimental system is designed, the braking force equation is verified with the experimental result, and the result of experiment is analyzed.
Simulation and optimization of dynamic characteristics of intelligent AC contactor
Authors: Zhang Guogang , Chen Wei , Ke Chunjun , Zheng Peng , Geng Yingsan
Published: December 2018

Dynamic characteristics reflect the real situation of an AC contactor and are very important to the optimum design of AC contactors. A simulation model of intelligent AC contactor has been established using the ADAMS software with developing a user subroutine in which the iterated Runge-Kutta method is adopt to solve a set of differential equations that describe the coupling of circuit, electromagnetic and mechanical systems. Because of reusing the analysis results obtained from the simulation of static characteristics accomplished by the ANSYS software, the simulation model runs more efficiently. In addition, by using the ADAMS/solver in the batch mode, an optimization library have been integrated with the ADAMS software and successfully used to seek the optimal control parameters to minimize the contact bounces and core bounces. The simulation results show that the intelligent AC contactor with PWM control can effectively reduce the bounces and energy consumption.
The application of CE/SE scheme in the simulation of 2-dimension expansion of ablation plasma jet in open air
Authors: Liu Dong-Yao , Zhou Yan-Huang
Published: December 2018

The 2-dimensional unsteady expansion process of plasma jet ablated in capillary because of the discharging of pulse power is simulated with CE/SE(conservation element / solution element) scheme in this paper. The high resolution computational space-time CE/SE scheme is simplified and improved to solve the axisymmetric two dimensional Euler equations of the unsteady expansion process of ablation plasma jet in open air. The variation and distribution of pressure and velocity of ablation plasma jet in flow field are illustrated and analysed. The shock wave and discontinuity of the jet are clearly depicted according to results of simulation, and simulating results are well agreement with experiment.
Optimum design of dry-type air-core reactor based on the additional constraints balance and hybrid genetic algorithm
Authors: Zhao Yanzhen , Chen Feng , Kang Bo , Ma Xikui
Published: December 2018

In this paper, the optimum design of round-wire dry-type air-core reactor is considered. An optimum design model is built based on the balance of three additional constraints, which is consist of layer resistance drop equalization, package temperature rise equalization and package height equalization. It is proved that the three additional constraints can not be simultaneously satisfied for a round-wire reactor when the number of packages is greater than 1. For this reason, the additional constraints balance is proposed for the optimum design of a reactor. According to the optimum design model, a new hybrid genetic algorithm combined with simplex method is introduced and studied in detail. The hybrid genetic algorithm can enhance the local searching ability and improve the optimization efficiency. Finally, the proposed method is applied to the optimum design of dry-type air-core reactor, and a satisfied result is obtained.