• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.277-296
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• 2016

There is a need for rapid and objective assessment of concrete bridge decks for maintenance decision making. Infrared Thermography (IRT) has great potential to identify deck delaminations more objectively than routine visual inspections or chain drag tests. In addition, it is possible to collect reliable data rapidly with appropriate IRT cameras attached to vehicles and the data are analyzed effectively. This research compares three infrared cameras with different specifications at different times and speeds for data collection, and explores several factors affecting the utilization of IRT in regards to subsurface damage detection in concrete structures, specifically when the IRT is utilized for high-speed bridge deck inspection at normal driving speeds. These results show that IRT can detect up to 2.54 cm delamination from the concrete surface at any time period. It is observed that nighttime would be the most suitable time frame with less false detections and interferences from the sunlight and less adverse effect due to direct sunlight, making more "noise" for the IRT results. This study also revealed two important factors of camera specifications for high-speed inspection by IRT as shorter integration time and higher pixel resolution.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.467-480
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• 2004

It is very important to eliminate thermal background radiation for the near infrared camera system such as KAONICS (KAO Near Infrared Camera System). Thermal background radiations which come from window and cryostat wall influence IR detector and decrease IR system performance. Therefore the cold box which contains optics and detector housing must be cooled down to eliminate thermal background radiation. We carried out quantitative analysis to determine internal cooling temperature to reduce thermal noise in the J, H, Ks, and L bandpass. Additionally, we estimated the incoming heat load and then chose the cryocooler adequate to KAONICS's requirements. The cooling time and the final cooling temperature of the cold box were calculated. These results were also implemented to the system design.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.50.1-50.1
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• 2014

The Multi-purpose InfraRed Imaging System (MIRIS) is the main payload of Science and Technology Satellite 3 (STSAT-3), which was launched onboard Dnepr rocket from Russian Yasny Launch Base in November 2013. The MIRIS is an infrared (IR) camera, and the telescope has to be cooled down to below 200K in order to reduce thermal background noise. For the effective cooling and low-power consumption, we applied passive cooling method to the thermal design of the MIRIS. We also conducted thermal analysis and tested for the passive cooling before the launch of STSAT-3. After the launch, we have received State-of-Health (SOH) data from the satellite on orbit, including temperature monitoring results. It is important that the temperature of the telescope was shown to be cooled down to below 200K. In this paper, we present both the temperature data of the MIRIS on orbit and the thermal analysis results in the laboratory. We also compare these results and discuss the verification of the passive cooling.