International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Albanese, Raffaele | Ambrosino, Giuseppe | Cannas, Barbara | Fanni, Alessandra | Pironti, Alfredo | Rubinacci, Guglielmo | Sias, Giuliana | Ventre, Salvatore | Villone, Fabio

Article Type: Research Article

Abstract: This paper proposes an approach aimed at avoiding or mitigating the consequences of a plasma disruption in a tokamak. The control strategy is based on a Disruption Predictive Control (DPC) where the use of a set of disruption predictors could allow actively modification of some plasma parameters when a disruption warning is issued. The DPC approach requires the continuous monitoring of various plasma performance indicators, which play the role of disruption precursors. The active control is …based on the availability of magnetic and nonmagnetic plasma parameter response models as well as multivariable control algorithms and architectures. Show more

Keywords: Tokamaks, MHD, disruptions

DOI: 10.3233/JAE-2012-1445

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 73-79, 2012

Authors: Hołub, Marcin

Article Type: Research Article

Abstract: Proposed paper deals with the subject of plasma power measurement in dielectric barrier discharge (DBD) reactors. Four approaches are compared including analytical, electrical, Lissajous figure and comparative methods. Discussion is led regarding measurement sensors, digital oscilloscope time base resolution and measurement capacitor technology. Lissajous curve approach gives results that are very comparable to definition based power calculation. Analytical approach, due to technical reasons, is inadequate, comparative approach gives slightly elevated values with …respect to other methods. Measurement capacitor value should be of comparable capacitance to reactors overall capacitance, a pulsed technology capacitor should be used for measurements. Show more

Keywords: Plasma power, DBD plasma, plasma power measurement

DOI: 10.3233/JAE-2012-1446

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 81-87, 2012

Authors: Zhang, Wei | Xu, Hailiang | Bai, Yanan | Yang, Shiyou

Article Type: Research Article

Abstract: To eliminate the deficiency of traditional evolutionary algorithms in numerical implementations with respect to the three key operators such as selection, crossover and mutation operators, a new evolutionary algorithm based on probabilistic models, the quantum-inspired evolutionary algorithm (QEA), is studied for design optimizations of electromagnetic devices. In the proposed QEA, an adaptive update formulation is proposed for the rotation angle to balance the exploration and exploiting searches while the two level information …sharing is simplified to one level one to facilitate the implementation of the proposed algorithm. Also, a new information sharing mechanism is introduced. The proposed algorithm is evaluated on an engineering inverse problem with promising results. Show more

Keywords: Quantum-inspired evolutionary algorithm, inverse problem, evolutionary algorithm based on probabilistic models

DOI: 10.3233/JAE-2012-1447

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 89-95, 2012

Authors: Murakami, Iwanori | Kobayashi, Yusuke | Gyoda, Masashi | Ando, Yoshinori | Yamada, Kou

Article Type: Research Article

Abstract: In this study, we propose a new magnetic levitation synchronous motor with a high-Tc superconducting bearing. The levitation rotor obtains the levitation force by the magnetic attraction and the restoring force (axially and radially to the shaft) from a superconducting bearing. The levitation rotor to which the magnetic flux concentration method is applied has a large magnetic field outside of the rotor. Because the superconducting bearing constrains this concentrated magnetic flux, the rotor obtains a large …restoring force. In addition, a superconducting bearing with a small bulk can be realized. We stabilized the rotor using this method and confirmed that this motor passed the resonance and that its speed increased to approximately 3500 [rpm] without control. Show more

Keywords: Synchronous motor, magnetic levitation, superconducting bearing

DOI: 10.3233/JAE-2012-1448

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 97-103, 2012

Authors: Tian, Shuxia | Chen, Zhenmao | Li, Yong | Zuo, Yongbin | Wang, Xiaowei

Article Type: Research Article

Abstract: The wire breakage identification of superconducting multistrands Cable in Conduit Conductors (CICC) is a key point to guarantee the reliability of the magnet system of the International Thermonuclear Experimental Reactor (ITER). In this paper, a Nondestructive Testing (NDT) method based on the measurement of magnetic fields surrounding CICC and the reconstruction of the current values in the superconducting cables from the measured magnetic field signals is presented. The validity and efficiency of the proposed method are …demonstrated through numbers of numerical simulations and preliminary experiments. Show more

Keywords: Wire breakage, CICC, ITER, NDT, Inverse analysis

DOI: 10.3233/JAE-2012-1449

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 105-112, 2012

Authors: Ferraioli, Fabrizio | Formisano, Alessandro | Martone, Raffaele

Article Type: Research Article

Abstract: Human brain electric activity related to important physiological functions can be pictured from bio electric and/or bio magnetic measurements through inverse problems approach. In this paper an iterative strategy is presented. The strategy is optimized to reconstruct brain activity confined in a sub region of the brain volume by jointly processing both bioelectric and biomagnetic signals. The procedure takes advantage from intermediate evaluations to improve the resolution, while limiting the number of unknowns. …The advantages of the proposed approach is a higher robustness against noise and uncertainty and better effectiveness. Show more

Keywords: Sources estimation problems, ElectroEncephaloGraphy, MagnetoEncephaloGraphy

DOI: 10.3233/JAE-2012-1450

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 113-120, 2012

Authors: An, Siguang | Liu, Lei | Yang, Shiyou

Article Type: Research Article

Abstract: An improved normal boundary intersection (NBI) method is proposed. To overcome the deficiency of NBI methods in finding one Pareto solution in a single run, the utopia plane is divided into sub-domains. Dual external archives are proposed to enhance the diversity of the population. A new elite strategy is introduced to keep the balance between global and local searches. Two counter vectors are defined and used to record the mapping rate and selection rate of each …sub-domain to act as elites to guide searches. The projection distance is employed to select candidates for next cycle of iterations. The expending of the ideal plane is implemented to sample completely the whole objective space and obtain an even distributed Pareto front. To validate the proposed algorithm, it is used to solve mathematical functions and an inverse problem with promising results. Show more

Keywords: Normal boundary intersection method, inverse problem, multi-objective, evolutionary algorithm

DOI: 10.3233/JAE-2012-1451

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 121-127, 2012

Authors: Wołoszyn, Mirosław

Article Type: Research Article

Abstract: The magnetometric method is used among other things on mobile platforms (planes, helicopters) in military systems and in geological research. Optically-pumped and SQUID magnetometers are used in magnetic systems on airplanes. To be able to attain the sensitivity of modern magnetometers in flight, it is important that maneuver-related magnetic interference effects be minimized. The mathematical model of an aircraft as a source of magnetic interferences has been known since the early 1950's. Modern computer programs …analyzing electromagnetic fields allow us to carry out the analysis of individual sources of aircraft interference. The results of numerical analysis of magnetic interferences of an aircraft model caused by permanent and induced magnetization and by eddy currents, are presented in this paper. The possibility of a significant reduction in an aircraft's magnetic interference by collecting data from more than four cardinal magnetic directions while in flight, is the most important conclusion of these computer simulations. Show more

Keywords: Magnetic interference, aircraft, computer simulations

DOI: 10.3233/JAE-2012-1452

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 129-136, 2012

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

Article Type: Research Article

Abstract: Lattice sandwich metallic plate (LSMP), a new multifunctional material with special advanced mechanical behaviours, has potentials to be applied to many important industries. Defects in welding joints of the LSMP may significantly reduce the material strength. Eddy Current Testing (ECT) is considered as a powerful NDT tool for the detection and sizing of defects in LSMP. The welding zone noises in ECT signals swarm the crack signals and may reduce the reliability of the quantitative defect …evaluation. To overcome this difficulty, an inversion algorithm based on the strategy of multi-frequency ECT is proposed in this paper for sizing of welding zone crack. Good consistency of the reconstruction results is obtained for both simulated and measured ECT signals, which proves the validity of the proposed scheme. Show more

Keywords: Quantitative NDE, lattice sandwich metallic plate, crack, welding noise, multi-frequency inversion algorithm

DOI: 10.3233/JAE-2012-1453

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 137-143, 2012

Authors: Wu, Lie | Yang, Shiyou | Bai, Yanan | Machado, José Márcio

Article Type: Research Article

Abstract: The study of robust design methodologies and techniques has become a new topical area in design optimizations in nearly all engineering and applied science disciplines in the last 10 years due to inevitable and unavoidable imprecision or uncertainty which is existed in real word design problems. To develop a fast optimizer for robust designs, a methodology based on polynomial chaos and tabu search algorithm is proposed. In the methodology, the polynomial chaos is employed as a …stochastic response surface model of the objective function to efficiently evaluate the robust performance parameter while a mechanism to assign expected fitness only to promising solutions is introduced in tabu search algorithm to minimize the requirement for determining robust metrics of intermediate solutions. The proposed methodology is applied to the robust design of a practical inverse problem with satisfactory results. Show more

Keywords: Robust design, polynomial chaos, design optimization, tabu search algorithm

DOI: 10.3233/JAE-2012-1454

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 145-150, 2012