International Journal of Applied Electromagnetics and Mechanics - Volume 45, issue 1-4

Authors: de Oliveira, B.G.M. | de Melo, M.T. | Machado, G.G. | Llamas-Garro, I.

Article Type: Research Article

Abstract: The authors present a new compact coplanar interferometer for application in an IFM system with 4 bits that operates in a frequency band from 5 to 6 GHz. This interferometer consists of a couple of coplanar two-way Wilkinson power dividers connected to two CPS lines with different signal delays. This interferometer presents smaller dimensions when compared to other designs. Details of this compact coplanar interferometer are provided along with a comparison between theoretical, simulated and measured …results. Show more

Keywords: Electronic warfare, frequency estimation, microwave devices, RF signals

DOI: 10.3233/JAE-141835

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 235-240, 2014

Authors: Genest, Marc | Mandache, Catalin

Article Type: Research Article

Abstract: In its current state, the wide acceptance of the Magneto-Optical Imaging (MOI) technique is hindered due to noise, lack of recordable results, and impossibility of data post-processing. This paper presents some add-ons made to a commercial MOI system to ease the image interpretation, archiving and reporting of the results. In addition, a few image processing techniques are also employed in an attempt to perform automatic flaw detection. The recording capability of the MOI instrument output images …was addressed by digitizing the video signal in video or image files. To help with the identification of the damage location and distance between images, a rotary quadrature encoder was mounted onto the MOI scan head. The use of the encoder allowed the identification of the inspection location with respect to a reference position, such as the beginning of the scan. Moreover, it allowed saving images at fixed intervals, which were then stitched into a single image, thus simplifying the post inspection analysis process. Both live and post-inspection image processing capabilities were made available. Implemented image processing included background subtraction, de-noising, contrast adjustment and morphological operation, among others. Contrast stretching transform and background subtractions were found to be among the most powerful techniques that could be used in simplifying the image interpretation. Show more

Keywords: Magneto-optical imaging, non-destructive evaluation, image processing

DOI: 10.3233/JAE-141836

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 241-246, 2014

Authors: Hong, Do-Kwan | Joo, Daesuk | Woo, Byung-Chul | Koo, Dae-Hyun

Article Type: Research Article

Abstract: The aim of the present study is to develop a motor-generator that fits into a microturbine generator (MTG) system with a power density of 500 W class considering the DC load. The performance evaluation of the motor-generator is performed by back-to-back tests according to AC and DC load to evaluate the power generating characteristics. The power generating characteristics simulation is compared with the experimental results. The analysis results are in accord with the experiment results considering …AC and DC loads. The slot model is determined by several characteristics, such as size constraint and the mechanical and electrical performance results between slot and slotless models. Show more

Keywords: 500W class microturbine generator, motor-generator, slot stator core, slotless stator core, super high speed

DOI: 10.3233/JAE-141837

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 249-256, 2014

Authors: Mori, Masaki | Kitagawa, Wataru | Takeshita, Takaharu

Article Type: Research Article

Abstract: This paper presents the characteristic analysis of the two-degree-of-freedom cylindrical actuator that can move in rotary and linear direction. The actuator uses the permanent magnet that is magnetized in axial direction so that the polarity in rotary and linear direction is generated alternately. When the rotary coil or the linear coil is excited, the mover moves by the principles of PMSM or PMLSM, respectively. As a result, the torque and the thrust are almost out of …interference. It was confirmed that the actuator can move in rotary and linear motion independently. Moreover, the iron loss of the mover is smaller than that of the stator in rotary and linear motion, and the hysteresis loss is much larger than the eddy current loss. Show more

Keywords: Two-degree-of-freedom, PMSM, PMLSM, iron loss, finite element method

DOI: 10.3233/JAE-141838

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 257-264, 2014

Authors: Mandache, Catalin

Article Type: Research Article

Abstract: In recent years, solid-state devices made their way in the development of electromagnetic non-destructive evaluation (NDE) probes. This fact was evidenced especially for pulsed eddy current, where magneto-resistive and Hall effect devices are used as sensing elements. Their low frequency range and small surface area are suitable to improve the detection of buried and small discontinuities. Although their properties are expected to enhance detectability over simple induction coils, this was still to be proven or …demonstrated in a comparative study. This work compares the sensing capabilities of an induction coil to those of two solid-state devices: giant-magneto-resistive (GMR) and Hall effect sensors. All of them are used as detectors in pulsed eddy current probes that have the same excitation mechanism, a ring-type copper coil driven by a constant amplitude square waveform. While the excitation part of the probe is fixed, the sensing components are inter-changeable. Although both induction coils and solid-state sensors output a voltage value as an indication of the magnetic field they are detecting, the voltage for pick-up coils is directly proportional to the rate of change of the magnetic flux. For solid-state sensors the output is in direct relation to the detected magnetic field. Under this study, all three sensing elements are used to detect the driving coil's magnetic output (magnetic field or flux) in air, on planes perpendicular and parallel to the face of the driver coil. The results obtained by all three sensors are quantitatively compared. Then the sensing devices are inserted in the inner space of the driving coil and, subsequently, used for detection of artificially made defects. Finally, the results are compared in terms of magnetic field sensitivity and inspection performance. Show more

Keywords: Magnetic sensing, pulsed eddy current, non-destructive evaluation

DOI: 10.3233/JAE-141839

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 265-271, 2014

Authors: Desideri, Daniele | Cavallin, Tommaso | Maschio, Alvise

Article Type: Research Article

Abstract: An improved version of a coaxial sample holder with continuous inner conductor for measuring the shielding effectiveness of planar films is presented. Keeping the design idea of the previously realized version of inner conductor split in two parts that are screwed on the sample under test, new aspects are: presence of tapered transitions, compact realization, and overall small size (total length less than 150 mm; maximum diameter of the cylindrical device of 48 mm). The theoretical …only TEM mode maximum frequency is about 5 GHz. The assembly of the device is easy, as it is the sample preparation. Experimental data have been get in the range 0.1 MHz–3 GHz by using a vector network analyzer. The reliability of the system has been proved by using, as reference samples, copper and aluminium thin films deposited by DC magnetron sputtering on kapton substrates. Films with different thicknesses have been prepared, with values around a few hundreds of nanometers, as measured by using a surface profiler. The shielding effectiveness experimental data of the used reference samples are reported and are well in agreement with the theoretical values. Show more

Keywords: Coaxial sample holder, planar film, shielding effectiveness

DOI: 10.3233/JAE-141840

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 273-278, 2014

Authors: Hong, Do-Kwan | Joo, Daesuk | Woo, Byung-Chul | Han, Pil-Wan

Article Type: Research Article

Abstract: The objective of the present study is to handle the optimum design of PMs excited TFLMs to transfer for high speed and heavy-load robots which transfer LCD glass panels to maximize thrust force and to minimize attraction force, thrust force ripple ratio, and attraction force ripple ratio. The predicted performance of the optimized TFLM is in accord with the 3-D FEM results. The static thrust force by test is performed to compare simulation results. The estimated …error is within 4.1%, and the developed prototype is operated for 3 m/s by synchronous control driver to control both 4,000 N class TFLMs. Experimental validation is successfully performed to verify the design and analysis by optimum design. Show more

Keywords: Thrust force 8,000 N class transverse flux linear motor, synchronous control, optimum design, response surface methodology (RSM), attraction force

DOI: 10.3233/JAE-141841

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 279-286, 2014

Authors: Horan, Peter | Underhil, Ross | Krause, Thomas W.

Article Type: Research Article

Abstract: Stress corrosion cracks may develop between fasteners in the aluminum inner wing spars of F/A-18 (CF188 Hornet) aircraft. These fasteners secure carbon-fibre/epoxy composite wing skin, of varying thickness (8 to 21 mm), to the spar. Inspection of the spar through the wing skin is required in order to avoid wing disassembly. A pulsed eddy current system that uses principal component analysis and discriminant analysis to identify cracks has been field tested at the USN North Island …facility. The results show that the system can accurately identify cracks in real time throughout the wing. The method is far faster than X-ray radiography and, because it is very portable, can be readily deployed to second or first line facilities. Issues that need to be addressed to improve the performance of the system are identified and potential solutions are examined. Show more

Keywords: Pulsed eddy current, aluminium, principal components analysis, discriminant analysis

DOI: 10.3233/JAE-141842

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 287-292, 2014

Authors: Santos, M.R. | de Oliveira, B.G.M. | de Melo, M.T. | de Oliveira, A.J.B. | Santos, E.A.B. | Freitas, R.D. | Serra, R. | Santos, M.M.L.

Article Type: Research Article

Abstract: This paper presents a switched smart antenna system, designed to provide a reliable communication between a Center for Integrated Operation of a distributor of electric power and automation devices such as electrical switches remotely controlled. The smart antenna system is controlled by an electronic device which sets de direction of the main lobe of an antenna array to the automation device.

Keywords: Smart antenna, switched system, automation devices, remotely controlled

DOI: 10.3233/JAE-141843

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 293-299, 2014

Authors: Wu, Wenjing | Zhu, Haitao | Jin, Ming | Dobashi, Katsuhiro | Fujiwara, Takesi | Uesaka, Mitsuru | Kusano, Joichi | Nakamura, Naoki | Tanabe, Eiji | Sunaga, Hideyuki | Otake, Yoshie

Article Type: Research Article

Abstract: Computed tomography system for in situ NDE of degradation bridges is under development, with portable 950 keV/3.95 MeV X-band linac as x-ray source. Collimator is adopted to reduce scattered X-ray noise and 3D model can be built from sectional images so that it becomes possible to evaluate mechanical characters of bridges referring to structural analysis with reduced stiffness. Furthermore, considering limitation of projection angle range during in situ scanning, reconstruction technique with incomplete projection data is …studied with experimental data. Show more

Keywords: X-band linac, CT, NDE, structural analysis, scattered X-ray noise

DOI: 10.3233/JAE-141844

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 301-306, 2014