• Title/Summary/Keyword: Electromagnetic induction instrument

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Measurement of Sea Ice Thickness in the Arctic Ocean Using an Electromagnetic Induction Instrument (전자기 유도 장비를 이용한 북극해 해빙의 두께측정)

  • Jeong, Seong-Yeob;Lee, Chun-Ju
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.2
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    • pp.189-195
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    • 2012
  • The ice trials of the first Korean icebreaking research vessel "ARAON" were performed at the Arctic Ocean in July-August 2010. The sea ice concentrations of Arctic Ocean were 4/10 to 10/10 and the range of sea ice thickness was roughly 1.0 to 3.5m. In this research, sea ice thickness characteristics at the old ice floes were determined from results of drill hole and apparent conductivity measurements. Especially we measured apparent conductivity using an electromagnetic induction instrument (EM31-MK2) and estimated the sea ice thickness through the empirical equation from Cold Regions Research & Engineering Laboratory, CRREL. The results of estimated sea ice thickness were compared to drill hole measurement results and then, we suggest the new empirical equation to estimate sea ice thickness of single layer type sea ice during the summer season of Arctic Ocean by curve fitting approach to these data.

A Measurement of Sea Ice Properties at Chukchi Borderland During the Summer (여름철 Chukchi Borderland 부근 해빙 재료특성 계측)

  • Jeong, Seong-Yeob;Choi, Gul-Gi
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.1
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    • pp.45-51
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    • 2012
  • Sea ice properties have been considered a key indicator in the structural design criteria of icebreaking vessels and arctic offshore platforms to estimate design ice load and resistance for their safety management in Arctic Ocean. A measurement study of sea ice properties was conducted during July to August of 2011 with the Korean icebreaking research vessel "Araon" around Chukchi Borderland. The sea ice concentration appears to be rapidly decreasing during this cruise. Ice condition seems to be thick second-year ice and multi-year ice and then, a lot of melt ponds were observed in the surface of ice floe. Calculated flexural strength of sea ice was about 250~550kPa, ice thickness was roughly 1.3~3.0m. In this research we performed field experiment to measure ice temperature along the depth, thickness, density, salinity, brine volume ratio and crystal structure. Apparent conductivities derived with the electromagnetic induction instrument were compared to drill hole measurement results and accuracy of sea ice thickness estimation formula was discussed.

Development of a Multichannel Eddy Current Testing Instrument(I) (다중채널 와전류탐상검사 장치 개발(I))

  • Lee, Hee-Jong;Nam, Min-Woo;Cho, Chan-Hee;Yoon, Byung-Sik;Cho, Hyun-Joon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.2
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    • pp.155-161
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    • 2010
  • Recently, the electromagnetic techniques of the eddy current testing(ECT), alternating current field testing, magnetic flux leakage testing and remote field testing have been used as a nondestructive evaluation method based on the electromagnetic induction. The eddy current testing is now widely accepted as a NDE method for the heat exchanger tube in the electric power industry, chemical, shipbuilding, and military. The ECT system mainly consists of the synthesizer module, analog module, analog-to-digital converter, power supplier, and data acquisition and analysis program. In this study, the synthesizer module and the analog module which are essential to the ECT system were primarily developed. The developed ECT system is basically a multifrequency type which is able to inject the maximum four frequencies based on the frequency and time domain multiplexing method. Conclusively, we confirmed that the EC signal was processed appropriately in each circuit modules, and the Lissajous EC signal was displayed in the impedance plane.

Development of a Multichannel Eddy Current Testing Instrument(II) (다중채널 와전류탐상검사 장치 개발(II))

  • Lee, Hee-Jong;Nam, Min-Woo;Cho, Chan-Hee;Yoo, Hyun-Joo;Kim, In-Chel
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.5
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    • pp.552-559
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    • 2011
  • Recently, the eddy current testing(ECT), alternating current field testing, magnetic flux leakage testing and remote field testing have been used as a nondestructive evaluation method based on the electromagnetic induction phenomenon. The eddy current testing is now widely accepted as a NDE method for the heat exchanger tube in the electric power industry, chemical, shipbuilding, and military. The ECT system mainly consists of the synthesizer module, analog module, analog-to-digital converter, power supplier, and data acquisition and analysis program. In the previous study, the synthesizer module and the analog module which is essential to the ECT system were primarily developed, and in this study the data acquisition and analysis program were developed. The operation system for this program is based on the Windows 7, and optimized for the Korean users, and the specific feature of this program using setup wizard enables inspector to make a setup easily for acquisition and analysis of ECT data. In this paper, the configuration and functions of eddy current data acquisition and analysis program will be introduced.