International Journal of Applied Electromagnetics and Mechanics - Volume 52, issue 1-2

Authors: Safdarnejad, S. Morteza | Su, Zhiyi | Ye, Chaofeng | Udpa, Lalita | Udpa, Satish

Article Type: Research Article

Abstract: EC-GMR measurements have been applied for detection of sub-surface corrosion and cracks under fastener (CUF) head. Generally, fastener signal amplitude is larger than the amplitude of the crack signal indication, rendering crack detection a challenging task. Also, another challenge in the analysis of field signals is the stitching problem, commonly present in a raster scan of a row of fasteners. We propose a method based on robust sparse coding (RSC) representation to alleviate the stitching problem and enhance defect detection capability. For the dictionary, we simulate multi-layer geometries using finite element (FE) modeling. Results on simulated and field data …demonstrate the feasibility and robustness of the proposed algorithm. Show more

Keywords: EC-GMR, crack under fastener, sparse coding

DOI: 10.3233/JAE-162109

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 415-423, 2016

Authors: Ye, Chaofeng | Udpa, Lalita | Udpa, Satish

Article Type: Research Article

Abstract: The detection ability of a rotating field transceiver probe designed for axial and circumferential notches for inspecting tubes is studied in this paper. The transceiver probe consists of three identical windings, located 120° apart, on the same physical axis. A three-phase sinusoidal current source is used for exciting the coils. The probe achieves the functionality of a mechanical rotating probe electronically and eliminates the need for mechanical rotation. A three-dimensional finite element model is used to simulate and predict the response of the probe to a variety of machined notches. The feasibility of detecting the axial and circumferential position of …a defect by analyzing the amplitude and phase of the transceiver probe signals is studied. A prototype of the probe was built and evaluated using an Inconel tube with axial and circumferential defects. Show more

Keywords: Eddy-current testing, rotating field probe, steam generator tube, finite element method

DOI: 10.3233/JAE-162219

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 425-433, 2016

Authors: Yang, Jiaqiang | Yang, Shiyou | Huang, Jin

Article Type: Research Article

Abstract: To alleviate the requirement on excessive computational resources using numerical methods such as finite element analysis in solving large high frequency 3-D eddy current problems, a novel iterative methodology to deal with periodic boundary conditions is proposed. Its implementation in finite element method is also explained in details. Numerical results on the computations of 3-D eddy current fields of a cold crucible are used to demonstrate the robustness and feasibility as well as the advantages of the proposed methodology in solving practical 3-D eddy current field problems.

Keywords: Eddy current, finite element analysis, iterative procedure, numerical solution

DOI: 10.3233/JAE-162191

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 435-442, 2016

Authors: Cheng, Yuhua | Yin, Chun | Chen, Yifan | Bai, Libing | Huang, Xuegang | Zhou, Xiaodong | Yang, Fan

Article Type: Research Article

Abstract: Eddy current pulsed thermography (ECPT) has been applied for a wide range of conductive materials. The enhancement of thermography to detect the defects is also important. This paper proposes an independent component analysis (ICA) fusion method based fuzzy algorithm to process the thermography images. In ICA, three kinds of contrast function are applied to obtain the different ICs respectively. Then, the corresponding fused ICs are obtained by the fuzzy fusion algorithm. Meanwhile, the kurtosis of each ICs before and after fusion are computed to evaluate the performance of the proposed method. In addition, an experiment is utilized to show the …benefits of the proposed ICA fusion method. Show more

Keywords: Fuzzy fusion, ICA, ECPT

DOI: 10.3233/JAE-162045

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 443-451, 2016

Authors: Vértesy, Gábor | Gasparics, Antal | Pávó, József | Gyimóthy, Szabolcs

Article Type: Research Article

Abstract: Fluxset magnetic sensor based probes with a double exciting coil system have been developed for detecting weakly interacting, low mass and small size magnetic particles for biomedical application. The probe measures the magnetic response of particles to an AC excitation. Measurements were carried out on samples containing 20, 30 and 40 nm size nanoparticles, which were embedded in a cylinder containing aguar-aguar. It was shown that the probe can detect nanoparticles of 20 nm size if their concentration is at least 0.06 mg/mm3 from a distance of 1 mm with reliable signal to noise ratio. The probe detection was …found to be improved after magnetization of particles. Show more

Keywords: Magnetic Fluxset sensor, magnetic nanoparticle, weak interaction, low mass particle

DOI: 10.3233/JAE-162209

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 453-460, 2016

Authors: Furukawa, Shoichi | Kobashi, Shoji | Kamiura, Naotake | Hata, Yutaka | Imawaki, Seturo | Ishikawa, Tomomoto

Article Type: Research Article

Abstract: In this paper, broadband ultrasonic imaging is presented to check the diameters of tubules. The proposed method applies continuous wavelet transform instead of short-time Fourier transform, and hence overcomes both issues of spatial resolution and frequency resolution. The proposed method can visualize positions of test objects more clearly than the previous work.

Keywords: Medical system, ultrasonic, azoospermia, seminiferous tubule, continuous wavelet transform

DOI: 10.3233/JAE-162034

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 461-469, 2016

Authors: Zhang, Wenguang | Ma, Yakun | Li, Zhengwei

Article Type: Research Article

Abstract: Brain micromotion is one of the key factors that influence the longevity of neural probes. In order to improve the long-term stability of brain implanted electrodes, finite element (FE) models, utilizing hyper-viscoelastic constitutive equations, are developed to conduct a series of dynamic analysis of the neural probe-brain model. The influences of neural probe geometry parameters (e.g. tip fillet, wedge angle, wall thickness) on micromotion induced brain injury are investigated. The results show that fillet radius of 20 micrometers keeps both the maximum strain and injury zone in a small region while wedge angle of 70 degree leads to a 10.34% …reduction in strain and 34.52% reduction in injury zone. Wall thickness of 15 micrometers generates the minimal injury zone and should be minimized under the condition of probe strength. The results will provide guidance on the development of novel neural probes with long-term stability. Show more

Keywords: Micromotion, neural probe, geometry parameter, finite element

DOI: 10.3233/JAE-162178

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 471-477, 2016

Authors: Yukawa, Atsushi | Kono, Atsushi | Nishii, Tatsuya | Kamiura, Naotake | Kobashi, Syoji | Hata, Yutaka

Article Type: Research Article

Abstract: Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the lung diseases caused by thrombi, which occurs in pulmonary arteries. By measuring a size of region dominated by arterial subtree which has thrombi, physicians find a higher treatment effect point. This paper proposes an automated method to extract the lung region dominated by an arterial subtree from MDCT images. The method extracts an arterial subtree associated with a seed point and a region dominated by the extracted arterial subtree. And visualizes them. The results show a clinical ability of visualization and extraction of dominant region from MDCT Images.

Keywords: Chronic thromboembolic pulmonary hypertension, thrombus, pulmonary artery, MDCT image, fast marching method, distance transform

DOI: 10.3233/JAE-162184

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 479-486, 2016

Authors: Nishikawa, Shouhei | Sakai, Yoshitada | Hata, Yutaka

Article Type: Research Article

Abstract: This paper first describes the parameters of normal gait from the center of the foot pressure (CoP). In our experimental system, we obtain the foot bottom pressure distribution data by using load distribution sensor. After that, we calculate CoP by image processing and evaluate the movement of CoP by the parameters of normal gait. In this study, we employed 153 healthy subjects and acquired their foot bottom pressure distribution while walking. Next, we applied the normal gait parameters to one Down's syndrome child in 2 cases; with insoles and barefoot. As the results, we confirmed that the parameters of the …child was improved by using insoles. Show more

Keywords: Flat-footed, normal gait, Down's syndrome children, center of foot pressure

DOI: 10.3233/JAE-162164

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 487-493, 2016

Authors: Takeda, Takahiro | Mabuchi, Takuya | Kubota, Naoyuki | Hata, Yutaka

Article Type: Research Article

Abstract: This paper describes an air-coupled ultrasound measurement system to evaluate activities of inner muscle. The system measures inner muscle with lower constrain than conventional method by using MR image, X-ray CT and contacted ultrasound. In generally, sound intensity of air-coupled ultrasound is too small to measure it. To measure the small signal, the system employs a pulsar-receiver with high sensitive pre-amplifier, and wave detection method based on fuzzy inference finds transmitted wave from noisy received wave. The fuzzy inference is derived from characteristics of transmitted wave such as amplitude, frequency, similarity and traveling time. In the experiment, we evaluate the …accuracies of wave detection method for human body. Show more

Keywords: Ultrasound, fuzzy inference, inner muscle, air-coupled ultrasound

DOI: 10.3233/JAE-162052

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 495-501, 2016