bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling the environmental effects on the radiated fields of a passive RFID system
Authors: Shirvani Moghaddam Shahriar 
Published: December 2018

The main objective of this paper is to model environmental effects on the read range of radio frequency identification (RFID) system. In order to evaluate the performance of an RFID system in real applications, electric and magnetic radiated fields (E or H) of a circular loop antenna should be derived. In this investigation, three cases are considered, free space model, the case that there is a perfect parallel or non-parallel surface, and finally the general model considering non-parallel non-perfect conductive/dielectric surface. In general model, besides the method of images, a new approach is proposed which model non-parallel main and image CLAs as two equivalent vertical and horizontal loops. According to this model, the radiated fields and also induced voltage are functions of the current intensity, wavenumber, reflection coefficient of the surface, both angle and the distance between antenna and surface, and the distance between the RFID tag and reader. To compare the analytical values extracted from E and B formulas of proposed model and associated results derived from computational methods, MATLAB and FEKO outputs are compared in the same conditions. Using this new proposed model, the performance of an RFID system operating in metal environment and also effective read range can be evaluated. It is also able to show the environmental effects on radiated fields of reader as well as tag's antenna. In addition, the interference effect of different RFIDs can be easily modeled by these new formulas.
Eddy current loss analysis in the rotor of surface-mounted permanent magnet brushless machine with retainer
Authors: Lee Sang-Yub , Ro Jong-Suk , Jung Hyun-Kyo 
Published: December 2018

For a permanent magnet machine, temperature rise due to the losses in the rotor can affect the performance of the permanent magnet. This is a critical problem for the designers of electric machine. These losses, especially eddy current losses in the conductive part of the rotor, cause heat which cannot easily be mitigate due to the mechanical structure. Therefore, it is very important to consider the losses in the designing step to ensure that the machine operates stably. The most common technique of reducing the eddy current losses is to divide them into smaller parts. The analysis for this segmentation structure is only possible in 3D-FEM (Finite Element Method) and though this requires a considerable amount of time during design step. Therefore, it is necessary to calculate the eddy current losses rapidly and accurately. In this paper, an eddy current loss analysis method in the retainer of the permanent magnet machine which has a high power density is proposed. First, the concept of effective conductivity is introduced to solve the segmentation problems not to use 3D-FEM. Also, in order to improve the accuracy of the proposed method, the skin effect which occurs in high speed driving region is considered and a FFT analysis is also performed on the harmonic components of air gap flux density. Finally the thermal analysis result which is based on the loss analysis result is also demonstrated and it is verified to compare with the thermal experimental results.
Investigation on the magnetic bias current and electromagnetic force of power transformer in multi-layer soil area
Authors: Yang Fan , Dai Feng , Liu Xinghua , Yang Yongming , He Wei 
Published: December 2018

When HVDC transmission lines operate in the monopole ground return mode or asymmetric bipolar mode, DC current flows in the earth and DC magnetic bias will arise in neutral point grounding (NPG) transformers. In this work, the model to calculate the potential distribution for multi-layer soil structure is set up, then the magnetic bias current (MBC) is calculated. The magnetic field distribution in the NPG transformer is obtained according to MBC, and electromagnetic energy and force in the transformer are calculated. Finally, the influence on MBC, electromagnetic energy and force caused by soil parameters are investigated. Results indicate that thickness of the first layer and resistivity of the second layer have a greater contribution to MBC, electromagnetic energy and force. To avoid excessive vibration of the NPG transformer, the soil at grounding electrode with a greater thickness in the first layer and lower resistivity in the second layer is preferred.
Analytical and experimental approach of the high density transverse flux linear stepper motor
Authors: Zare Mohammad Reza , Misron Norhisam , Aris Ishak , Wakiwaka Hiroyuki 
Published: December 2018

Detailed analytical and experimental approaches were performed to calculating the ratio of the pull-in thrust to the input power of High Density Transverse Flux linear Stepper Motor (HDTFLSM) with considerations of the electrical time constant, the mechanical time constant and the friction. The analytical approach involves the use of Fourier series analysis to derive the equation for the pull-in thrust to input power ratio. The experimentation was performed under different load conditions until the motor come to the standstill value. A chopped voltage was applied to motor at different speeds and the obtained results were compared with those for normal voltage. Comparison between analytical and experimental results shows good agreement, for instance at 0.22 m/s the difference percentage on normal voltage and chopped voltage are 6.1% and 6.7%, respectively. The chopped voltage has higher ratio of the pull-in thrust to the input power compare to normal voltage so that the machine performance can be improvised to a greater extent. The maximum improvement percentage of 18.8% on pull-in thrust to input power ratio for motor with chopped voltage was obtained at 0.22 m/s.
Magnetostrictive deformation of a transformer: A comparison between calculation and measurement
Authors: Ghalamestani Setareh Gorji , Vandevelde Lieven , Dirckx Joris J.J. , Guillaume Patrick , Melkebeek Jan A.A. 
Published: December 2018

Magnetostriction, which refers to the deformation of the core material of transformers and electrical machines, is a main contributor to the total noise. In this work, a technique is proposed to calculate the magnetostrictive deformations of the core of the aforementioned devices. This technique is based on finite element approach with an artificial neural network model of the magnetostrictive behaviour of the core material. The strain measurements are carried out by using a dual heterodyne laser interferometer setup. The proposed technique is then applied to a single-phase test transformer core. As a validation, the vibration of the magnetised core of the same setup is measured by using a laser scanning vibrometer.
Design of an on-line observer of LIM servo systems using transient FEM and experimentation for sensorless vector control
Authors: Lee Jung Ho , Kim Young Hyun 
Published: December 2018

This study deals with the dynamic characteristic analysis of a Linear Induction Motor (LIM), using a finite element method in which a moving mesh technique is considered. The focus of this paper is to show the suitability of an on-line observer system for position sensorless control of a LIM under phase asymmetry, saturation and iron loss. Comparisons are given both from the angle of the observer and that of the proposed FEA method of a linear induction motor. The position control system is realized, and the effectiveness of the observer system for the flux angle is verified by experimental results.
An analysis of passive magnetic composites for suppressing the vibration of beams
Authors: Oh J. , Ruzzene M. , Baz A. 
Published: December 2018

The fundamentals of controlling the structural vibration of beams treated with a new class of Passive Magnetic Composites (PMC) are studied. The PMC is a constrained damping treatment, where a viscoelastic core is sandwiched between two layers of permanent magnets. The interaction forces between the magnets aim at enhancing the damping characteristics of the viscoelastic. The effectiveness of such treatments is demonstrated both numerically and experimentally. In particular, a finite element code is developed to model the interaction between the dynamic behavior of the beam, the viscoelastic layer and magnetic layers. The model is validated experimentally at various operating conditions and the performance of the treatment is evaluated for different configurations of the magnetic layers. The obtained results suggest the potential of the new class of PMC as an effective and simple mean for controlling structural vibrations.
A FFT integral formulation using edge-elements for Eddy Current Testing
Authors: Tamburrino A. , Ventre S. , Rubinacci G. 
Published: December 2018

This paper presents a new approach for reducing the computational cost needed to solve the forward problem, i.e. the prediction of the measurements of a given ECT measurement system. This issue is mandatory in any inversion algorithm which, typically, requires the solution of a large number of direct problems. Integral formulations are attractive for ECT since they require the discretization of the conductive body only. However they also give rise to a full stiffness matrix whose inversion, typically obtained using direct solvers, has a computational cost that grows as O(n^3) where n is the number of unknowns arising from the discretization. Iterative algorithms achieve a computational cost that is lower than direct solvers when the stiffness matrix is sparse. The approach proposed in this paper makes it possible to represent the stiffness matrix arising from an edge-elements based integral formulation, by means of the Fast Fourier Transform. This representation is achieved for bounded conductive domains meshed by a regular mesh and incurs a computational cost that grows as O(N \log h) .
Instability analysis of the surface of molten metal under high frequency electromagnetic fields
Authors: Yoshida Mitsuhiro , Morita Katsuaki , Kuwada Chie , Tanahashi Takahiko 
Published: December 2018

A high frequency electromagnetic field (HFEMF) that is applied to the surface of a molten metal is able to generate a Lorentz force on the surface of the molten metal. This force can be used to seal the molten metal leakage without contact, which makes the quality of metal products purer and the seal system used perform longer. To make this technique possible, it is required to analyze the surface shape and the surface instability when HFEMF is applied to the molten metal surface. It is known from experiment with various kinds of molten metal that the fluctuation of the surface occurs under the applied HFEMF. This fluctuation becomes stronger as the HFEMF is increased. The fluctuation is strongly connected to the instability criteria of the surface. This research has been carried out to make it clear how the HFEMF causes the surface fluctuation of the molten metal, and how it determines the surface shape and stability region. Also, the effects of gradient of HFEMF and DC magnetic field have been investigated.
Simulation in applying genetic algorithm for non-destructive measurement of electron beam transverse profile
Authors: Tomioka Satoshi , Nisiyama Shusuke , Enoto Takeaki 
Published: December 2018

For the purpose of non-destructive measurement of the cross-sectional shape of an electron beam, we have studied a detection system that is composed of both a number of antennas and a current monitor. The antenna detects an electric field, and the current monitor detects an integral of beam currents. The signals acquired from these detectors are applied as the input of an inverse problem. We adopt the genetic algorithm to simulate the profile measurement as an inverse problem analysis. The results showed that this detection system is partially effective, even though this system is an "ill-posed problem" (i.e. the number of input data parameters is less than the number of parameters to be estimated). We also found that the current monitor, which cannot acquire position-dependent information, is nevertheless useful to accelerate the convergence of sub-optimal beam profiles.
Clinical applications and recent progress of therapeutic artificial organ using moving-actuator mechanisms
Authors: Lee J.C. , Chung J. , Rho Y.R. , Lim K.M. , Kim J.C. , Park J.Y. , Lee D.W. , Choi H. , Lee S.M. , Choi D.S. , Nam K.W. , Lee J.J. , Park J.W. , Choi S.W. , Choi J. , Park C.Y. , Park S.K. , Son H.S. , Hwang C.M. , Kim H.K. , Sun K. , Yoon Y.M. , Lee K.K. , Won Y.S. , Min B.G. 
Published: December 2018

Therapeutic Artificial Organs (TAO) are extracorporeal life-saving devices that are used to bridge patients from emergency to surgery and recovery. This paper details the research on TAOs in Korea along with their development as the clinical devices. In the heart and lung area, the artificial heart system (AnyHeart) and the pulsatile heart-lung machine (T-PLS) have been developed. The T-PLS has been used in 400 patients. In the renal replacement area, the portable hemofiltration machine (C-PAK) and its applications in home renal treatment are currently being tested through animal experiments. The multiple applications of the biomaterials, the electromechanical system designs and their control, the telecommunication technology and medical technology have been combined in the research and development of life-saving artificial organs for critically ill patients.
Inverse problem solution algorithms in magnetocardiography: New analytical approaches and some results
Authors: Primin M. , Nedayvoda I. 
Published: December 2018

This paper describes the development of the magnetostatic inverse problem solution methods for studies of the magnetic field of human heart(magnetocardiography – MCG). A set of N different dipole sources is associated with the spatial distribution of the heart magnetic field parameters, measured in the observation plane. Methods: Estimation of the field sources quantity in the heart for a given time-point of the average cardiocycle is obtained after spatial-and-time analysis of the spatial gradients intensity of the magnetic field in the observation area (plane). Relative powers of the field sources have been obtained by plotting the Voronoi diagram. Mutual locations(coordinates) of the sources in the heart volume are obtained after examining the analytical solution of the magnetostatic inverse problem for each of the N magnetic dipoles. Results: The analytical solution of the magnetostatic inverse problem for several magnetic field sources, independently distributed in a 3D volume, has been obtained. The validity of the problem solution is supported by the results of numerical and physical simulations. Conclusions: Algorithm of the magnetostatic inverse problem solution is implemented as a software package for the magnetocardiograph and used for cardiology diagnosis.
The constitutive equations of half coated metal core piezoelectric fiber
Authors: Bian Yixiang , Qiu Jinhao , Wang Xinwei , Ji Hongli , Zhu Kongjun 
Published: December 2018

The half coated metal core piezoelectric fiber (HMPF) is one of the new type piezoelectric devices for sensors and actuators. The constitutive equations of cantilevered HMPFs under various mechanical and electrical loading conditions are derived. The equations can describe the behavior of HMPF subjected to an external voltage V on the electrodes, a bending moment M at the free end of the beam, a lateral force F at the tip of the beam and a uniformly distributed load p on the whole length. The internal energy density of the beam is expressed in mechanical strain and electrical field. The internal energy is calculated by integrating the energy density over the whole volume of the beam. The voltage V, bending moment M, lateral force F, and distributed load p are generalized force acting on the fiber and their corresponding generalized displacement are the charge Q on the electrodes, the tip angleα, the tip deflection δ, the areal displacement A of the fiber. The constitutive equations give the dependence of the generalized displacements upon generalized forces. The equations are given in the direct form, with external parameters (M, V),(F, V), and (p, V) as independent variables and also in a linear combination with (M, F, p, V) as variables. The constitutive equations derived in this paper can be used for further analysis of HMPF sensors and actuators. Two experiments, in which a HMPF was used as a sensor or an actuator, were performed to verify the constitutive equations. The experimental results are compared with the numerical results.
Simulation and verification of the axial force of a linear permanent magnet synchronous actuator
Authors: Al-Sharif Lutfi , Taifour Sinan , Kilani Mohammad 
Published: December 2018

A methodology has been developed for the simulation and experimental verification of the axial force exerted by an electromagnet on a concentric permanent magnet. This comprises four stages. The first involves the modeling of the permanent magnet as a current sheet based on the permanent magnet material and its dimensions. This current sheet model is then discretised into a number of coils. The second stage involves the prediction of the radial magnetic flux density from the electromagnet at any point off its axis. The third stage involves the calculation of the axial force exerted by the electromagnet onto a concentric current carrying ring along its axis. The fourth stage involves the calculation of the axial force exerted by the electromagnet onto a number of contiguous rings that represent the model of the permanent magnet developed in the first stage. Experimental verification has been carried out for the fourth stage by the measurement of the resultant force by the use of weights. The method was implemented in matlab for all the four stages. In addition to the experimental verification, PC based verification was also carried out against a FEM software for the results from all the four stages.
Position control of magnetic beads by means of electromagnetic fields with respect to apodal locomotion systems
Authors: Greiser Steffen , Böhm Valter , Zimmermann Klaus 
Published: December 2018

Motivated by the technical progress, electromagnetic action principles are more and more used in micro systems. It is well known that the discrete positioning of magnetic beads like ferrofluid droplets can be realised using an array of electromagnets whereat the position of the beads depends on the arrangement of the electromagnets. This paper refers to the analogous positioning of magnetic beads independent from the arrangement of the electromagnets. Therefore a control strategy was designed to position magnetic beads like ferrofluid droplets, ferrogels or ferroelastomers. The derived control law allows the definition of dynamic properties like time and damping constant. To achieve these properties, the controller is adjusted based on a model of the plant. This model regards the dynamical movement of the mentioned materials in electromagnetic fields and is characterised by simplified, nonlinear, ordinary differential equations. The theoretical results are verified by means of a basic assembly allowing the positioning of spherical ferroelastomers on macro scale. The measurements illustrate that the theoretically derived position controller meets the requirements of a predefined time and damping constant.
Genetic algorithm for training dynamical object emulator based on RBF neural network
Authors: Sergeev S.A. , Mahotilo K.V. , Voronovsky G.K. , Petrashev S.N. 
Published: December 2018

The combination of Genetic Algorithms (GAs) and Artificial Neural Networks (ANNs) has already resulted in researchers advancing in quite a few real world applications but it is in control that this alliance yields such appreciable benefit. The paper reports a Radial Basis Function (RBF) network training technique which joins together global strategy of GAs and a local adjusting procedure typical for RBF networks. While activation function window centres and widths are processed via a “slow” numeric GA, output‐layer neurone synaptic weights are defined by a “fast” analytical method. The technique allows to minimize not only the network hidden-layer size but also the pattern set required for training the adequate dynamical object neuroemulator.
Physiological response and susceptibility of strawberry cultivars to the charcoal rot caused by Macrophomina phaseolina under drought stress conditions
Authors: Sánchez S. , Grez J. , Contreras E. , Gil P.M. , Gambardella M. 
Published: December 2018

BACKGROUND: Charcoal rot of strawberry ( Macrophomina phaseolina) is an emerging disease difficult to manage, a desirable alternative is the use of resistant cultivars. However, little is known regarding the reaction of cultivars to the pathogen under water stress conditions. OBJECTIVE: The aims of this work were to study the effect of water stress on the physiology of four strawberry cultivars during the infection, and to determine the relationship between water stress and cultivar susceptibility. METHODS: Healthy and inoculated plants of ‘Monterey’, ‘Albion’, ‘Camarosa’ and ‘Sabrina’ were maintained under no irrigation and full irrigation regimes, in greenhouse conditions. Stem water potential (SWP) and stomatal conductance (gs) were evaluated. The disease severity was recorded weekly for seven weeks. RESULTS: The disease detrimentally affected the water relations in ‘Sabrina’, ‘Albion’ and ‘Monterey’. A significant correlation was detected between the evaluated parameters and the disease severity. The disease severity increases in plants with no irrigation, regardless of cultivar. CONCLUSIONS: Our results show that the infection caused by M. phaseolina increases the negative effects of water stress, depending on the genotype, and that the cultivars that were able to maintain more stable water relations respond better to the disease.