International Journal of Applied Electromagnetics and Mechanics - Volume 41, issue 3

Authors: Ajoudanian, Mohammad | Jiang, Zhongwei | Morita, Minoru

Article Type: Research Article

Abstract: This paper is concentrated on analysis and design of the structures of the micro-stirrer which have high performance at a requested frequency for thrombus dissolution. In this paper the new type structure of micro-stirrer which transmits the longitudinal elastic wave through catheter and converts to a bending motion at the tip stirrer is described first in order to get high performance of thrombus dissolution. Next how to design the structure which can be driven at …a requested frequency without reduce the performance, because for dissolution of different type of thrombus it is necessary to drive micro-stirrers in a high performance frequency and with a certain deflection. To design and analysis the optimum structure, the modal analysis and harmonic analysis are carried on with the aid of FEM simulation. The results showed that it is possible to change the structures of the micro-stirrer to fit the requested driven frequency with keeping the high performance. The results also indicate that since the variations of design parameters are restricted rigidly, using the numerical simulation with proposed analysis model is a very efficient way to study the design of desirable structures. Show more

Keywords: Micro-stirrer, thrombus, frequency, structural design, thrombectomy

DOI: 10.3233/JAE-121606

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 217-225, 2013

Authors: Xiang, Shuhuang | Ma, Junjie

Article Type: Research Article

Abstract: Calculation of the Pollaczek integral is very important in evaluating the magnetic field in air generated by an underground conductor. This paper provides an efficient algorithm to calculate these integrals by splitting the semi-infinite range into two parts, where the integral tail is evaluated by complex integration methods, and the integral on the finite segment is calculated by the Clenshaw-Curtis quadrature. The computational cost remains the same regardless the frequency, and the higher the oscillation the …better the accuracy of the calculation. The efficiency and accuracy are tested by numerical examples. Show more

Keywords: Pollaczek integral, mutual impedance, complex integration, Clenshaw-Curtis quadrature

DOI: 10.3233/JAE-121607

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 227-236, 2013

Authors: Dziczkowski, Leszek

Article Type: Research Article

Abstract: The paper describes an innovative calibration method that makes it possible to efficiently measure the conductivity of workpieces with rough surfaces, where standard specimens with the already known properties are used for calibration. The calibration process leads to the determination of equivalent parameters of a probe. The measurements results are processed on line with the use of a simple mathematical model for the considered phenomenon. Finally, the determined conductivity value only slightly depends on the surface …condition of the examined workpiece. During the conductivity determination there was calculated a parameter–namely, the eddy-current factor of surface roughness–that compensates the impact of the surface roughness. The parameter can be treated as a specific roughness factor of the eddy-currents. The factor has been determined for several samples with already known mechanical values obtained with the help of Ra and Rz methods. Show more

Keywords: Conductometer, eddy currents, non-destructive tests, impedance calculation, electric metrology, surface roughness, properties of a material

DOI: 10.3233/JAE-121608

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 237-249, 2013

Authors: Guo, Xudong | Yan, Rongguo | Wang, Cheng

Article Type: Research Article

Abstract: A wireless electromagnetic localization method for tracking a medical micro-device in the gastrointestinal tract has been proposed and a prototype for the localization system has been developed. In the electromagnetic localization system, several excitation coils were mounted above the abdomen of human body to generate a varying electromagnetic field one by one. Then a wireless magnetic sensor was used to measure the magnetic field strength at the location of the micro-device. Thus the position and orientation …of the micro-device could be obtained by solving the inverse problem of magnetic fields. In order to improve the localization precision, a global error correction technique based on the Hardy's Multi-Quadric scattered data interpolation method was investigated to correct the static errors. In the calibration experiment, dependencies between true locations of the micro-device and the corresponding tracked locations within the operational space were established. Based on these data sets, the Hardy's Multi-Quadric correction function was derived. The experimental results show that the localization error can be greatly reduced by using the Hardy's Multi-Quadric correction method. The advantage of the approach is that it allows for smooth continuous mapping from the tracked space to the true space within the entire tracked space. Show more

Keywords: Electromagnetic localization, a wireless magnetic sensor, calibration, Hardy's Multi-Quadric method, intestinal micro-devices

DOI: 10.3233/JAE-121609

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 251-258, 2013

Authors: Cong, Haoxi | Zou, Liang | Zhang, Li | Li, Qingmin

Article Type: Research Article

Abstract: J-A model is widely used in hysteresis modeling as well as performance simulation of the magnetic materials. To achieve preferable adequacy, a modified J-A model is given, however, accurate solution of the parameters is very important for the modified J-A model, especially for over-determined nonlinear equations. In response to solving the over-determined nonlinear equations, this paper first turned the problem of the over-determined nonlinear equations into solving the minimum value of a multivariate function …by means of the least square method. While the multivariate function is of high nonlinearity (the function is not continuous and the matrix of the partial derivatives is singular), solution methods using derivative calculation were abandoned, and the direct seeking methods with no derivative calculations (simplex algorithm) were involved to solve the problem. In the end the solution was validated with the use of the genetic algorithm and the simulated annealing algorithm. Show more

Keywords: Modified J-A model, overdetermined nonlinear equations, least square method, optimization algorithm, simulation

DOI: 10.3233/JAE-121610

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 259-266, 2013

Authors: Izadi, M. | Ab Kadir, M.Z.A. | Askari, M.T. | Hajikhani, M.

Article Type: Research Article

Abstract: In this study an inverse procedure algorithm is proposed in the time domain to evaluate lightning return stroke current based on measured electromagnetic fields at an observation point. The proposed method considers on all electromagnetic fields components and can evaluate full shape of current, velocity and constant parameters of current models in contrast with previous studies. In order to validate the proposed method, a set of measured electromagnetic fields are applied on proposed algorithm and the …evaluated currents are compared to the corresponding measured current as well as the results are discussed accordingly. The proposed method can be used for preparing of current data bank that is very useful for considering on lightning effects on the power lines and setting appropriate protection levels on the power systems. Show more

Keywords: Return stroke current, electromagnetic, lightning

DOI: 10.3233/JAE-121611

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 267-278, 2013

Authors: Dalarsson, Mariana | Motevasselian, Alireza | Norgren, Martin

Article Type: Research Article

Abstract: A study of a novel method to detect mechanical deformations of windings in a power transformer, while in operation, is presented. We employ an approximate model of a transformer winding surrounded by the transformer-tank wall and the magnetic core. The transformer winding is viewed as a structure consisting of thin conducting cylindrical rings (winding segments or turns) situated within a coaxial cylindrical waveguide, where the inner conducting cylinder represents the iron core that conducts the magnetic …flux and the outer conducting cylinder represents the wall of the transformer tank. The basic principle is to insert antennas inside the transformer tank above and below the winding to radiate and measure microwave fields that interact with the metallic structure and the insulation. The responses from the radiated waves are assumed to be sensitive to any mechanical deformations that could be caused by electromagnetic forces due to short-circuit currents and possible manufacturing weaknesses. The goal is to be able to determine the radial locations of the individual winding segments or individual turns from measurements of the scattered fields at both ends. The propagation problem is solved by conventional waveguide theory, including mode-matching and cascading techniques. We utilize optimization as a suitable method to solve the inverse problem and obtain a good agreement between the reconstructed and true positions of the winding segments. Show more

Keywords: Inverse problem, multiple modes, power transformers, cylindrical windings

DOI: 10.3233/JAE-121612

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 279-291, 2013

Authors: Zhang, Dongli | Wang, Zhaoba | Chen, Zhenmao

Article Type: Research Article

Abstract: The anti-corrosive coating in pipeline and oil tanker is taken as a crucial component in petroleum industry and needs a robust NDE tool to evaluate its thickness. For the thick coating on the curved steel bases of various sizes, the eddy current sensor's evaluation capability for thick coating and the influence of the test-piece sizes on the evaluation precision are two key problems had to be solved. Taking into account the dimension effect of the sensor …on signals, a wide-range sensor was designed and applied to the coating evaluation. The relationship between coil responses and liftoff was investigated and a NDE strategy based on a polynomial coefficient database was proposed to cope with the influence of test-piece sizes. Its applicability was verified by simulation results. Show more

Keywords: Anti-corrosive coating, nondestructive evaluation, steel base, eddy current sensor, numerical simulation

DOI: 10.3233/JAE-121614

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 293-299, 2013

Authors: Priyandoko, Gigih | Baharom, Mohamad Zairi

Article Type: Research Article

Abstract: This paper presents a novel method for the Non-Parametric Modelling of Magneto-Rheological (MR) Dampers using Adaptive Neuro-Fuzzy (NF) that incorporates a Particle Swarm Optimisation (PSO) method. In this approach, the adaptive NF method is using an adaptive Back-Propagation (BP) learning algorithm, which is used to update the weights in real-time. Initial values of the weights and biases are optimised using PSO in an off-line manner. The experimental data was presented in the time histories of the …displacement, the velocity and the force parameters, measured for both constant and variable current settings and at a selected frequency applied to the damper. The model parameters were determined using a set of experimental measurements corresponding to different current constant values. It has been shown that the MR damper model's response via the proposed NF approach is in a good agreement with the MR damper test rig counterpart. Show more

Keywords: Magneto-rheological damper, adaptive neuro-fuzzy, particle swarm optimization, non-parametric modelling

DOI: 10.3233/JAE-121615

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 301-312, 2013

Authors: Provatidis, Christopher G. | Gamble, Michael A.

Article Type: Research Article

Abstract: This paper deals with the dynamic analysis for the calculation of the support forces in a rotating elastic rod when subjected to simple types of axial forces. For simplicity the model starts with a linear straight spring and a lumped mass and expands into a distributed system. The analysis shows a shift in the natural frequency of the support forces, due to rotation and additional axial oscillations, these are highly influenced by both the axial and the shear …forces, which are induced by the centripetal and Coriolis forces, respectively. Based on this finding, the paper shows that it is not possible to take advantage of the inertial forces and create long-term inertial thrust, even if the rotation is synchronized with the shifted natural frequency. The discussion includes extensions into the electromagnetic realm by comparing the mechanical system with its electrical equivalent. Show more

Keywords: Natural frequency, rotation, synchronization, structural response, electromagnetics

DOI: 10.3233/JAE-121616

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 41, no. 3, pp. 313-333, 2013