• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.337-345
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• 2018

In this study, observations of oil leakage samples taken from the actual site were performed to identify the causes of the oil leakage phenomenon. As a result, the separation of the material components was determined as the main cause of the oil leakage phenomenon based on the changes in the surface conditions, and verification of this was conducted. The evaluation results confirmed that the filler component of the asphalt mastic subsided with the lapse of the settling time, and that the difference ratio of the filler contents of the upper and lower specimens was up to 23.8% after day 28. Based on these results, a hypothesis on the oil leakage mechanism of asphalt mastic was established, and then modeling of the entire process of oil leakage was performed.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.19-29
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• 2019

In this study, a revised oil leakage evaluation method for assessing oil leakage stability of asphalt mastics used in upper slabs of below-grade residential parking lots was developed and presented. In order to verify the reliability and reproducibility of leakage results, the parameters the revised evaluation was carried out for three products with actual leakage history, and it was confirmed the leaks could be reproduced whereas the existing methods could not. To quantitatively verify the reproducibility, the filler content of the leaked samples was derived and the maximum filler content was 64% lower than that of the normal sample. The same results was found with the samples from the actual leakage site, thus verifying the reliability of the revised evaluation method.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.1
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• pp.56-65
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• 1998

An oil spill model, Green Sea Ranger(GSR) based on trajectory and fate modeling of spilt oil behavior is introduced. The various physical models on weathering processes are reviewed and those adopted by GSR are described. A database for currents, which is necessary for the real-time simulation of oil spill, is generated on the south sea of Korea. The real-time prediction of tidal currents in the South Sea of Korea is carried out. Four major constituents (M₂, S₂, K₁, O₁ tide) are employed in the prediction, and those angular speeds and phases are determined from the astronomical arguments. The harmonic constants of the constituents are computed by solving shallow-water tide equations. The GSR has user-freiendly GUI and flexible framework which makes it easy to expand the database for sea environments in Korean coastal waters. The GSR is validated by the simulation of O-Sung oil spill caused by a grounded oil tanker in coastal sea near Maemol-do. The simulated trajectory is compared with observed one and it is shown that the GSR gives reasonable estimation on spilt oil bahavior.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.568-569
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• 2019

20~30년 전부터 국내 지중송전선로에 OF(Oil Filled)케이블을 사용해 왔다. OF케이블은 오랜 시간동안 신뢰성을 화고하고 있으며, 전연파괴 사고를 미연에 방지할 수 있는 장점이 있지만 유지보수에 많은 어려움이 있고, 절연유에 의한 환경오염이 발생하며, 화재에 취약한 단점이 있다. 최근 20~30년 전에 설치된 OF케이블의 수명이 한계에 도달하면서 고장 위험성이 증가하고, 누유의 위험성이 도사리고 있다. 본 논문에서는 OF케이블 상태 진단방법에 있어서 절연유에 반응하는 필름센서를 활용하여 절연유 탱크의 연결부에서 누유현상을 감지하여 OF케이블 누유 관리시스템을 개발하자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.321-327
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• 2020

Engine oil leaks comprise the largest percentage of the major quality problems that have occurred during the engine production process for military land system equipment over the last two years. To minimize this, it is essential to understand the root cause of the engine oil leakage and perceive the more common leakage area, as well as reduce the quality costs of pre-identification for leaks in the engine assembly process and single items. Therefore, in this study, the mass production quality of engines installed and operated in power equipment was improved by visualizing the engine oil leakage injected with the fluorescent dye and increasing the identification of the engine oil leak phenomenon. For this reason, the possibility of substituting the engine oil was considered and the engine oil was injected with the fluorescent dye. The maintenance was improved by reforming the engine oil injection process and leakage inspection process. Finally, these results suggest that the quality costs between mass production processes can be minimized by ensuring the reliability of military engines by reducing the user's complaints and improving the quality control capabilities of engine manufacturers.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.338-341
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• 2007

This paper surveyed the deterioration phenomena of elevator system being operated in Apartments. It was proved that oil leakage, gear abrasion and metal corrosion are the main deterioration phenomena and the number of breakdown was increasing rapidly with 8 years elapsed from installations

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.490-497
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• 2017

The Main Landing Gear(MLG) of Rotary Wing Aircraft is an essential equipment in Landing System for pilot to perform a flight mission. It supports the fuselage at ground and absorbs the impact from the ground when landing, thereby, these functions sustain operational capability for pilot and crew. However, the A aircraft caused asymmetry and leakage hydraulic when it was stationed on the ground. Therefore, this paper summarizes pilot comments in operation which are classified by cause of occurrence and the troubleshooting process about each comment. It also describes design improvements which was derived from troubleshooting and suggests verification results of flight test.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.3-10
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• 2003

Oil drop formation during the underwater oil discharge is investigated experimentally. The focus is placed on the size of the drops formed with the variation of discharge speed and nozzle diameter. As the Reynolds number based on the nozzle diameter increases, the droplet size decreases first and then increases until an explosive atomization occurs. The length of the jet attached to the nozzle Increases with the Reynolds number and then decreases. The transition occurs when the flow becomes asymmetry.

• Fire Science and Engineering
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• v.27 no.5
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• pp.19-25
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• 2013

The fire took place in the synthetic heat transfer fluid boiler. This study uses simulation to investigate the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is more or less unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120 kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The simulation shows that the temperature is $767^{\circ}C$ in the low part of the third pass. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. The temperature rises to $183^{\circ}C$ in the low part of the burner. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.241-248
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• 2013

In this study, bearings were developed for a high-power propulsion motor operating in inclined operation conditions through a simulation and similitude-experimental methods using commercial rotating machinery dynamics analysis software. The developed journal bearing is electrically insulated and has low thermal conductivity because each part is connected with 2-4 -mm-thick epoxy plates. To realize an appropriate oil thickness, an oil lift system is adopted, and a half separated structure is applied to ensure the feasibility of maintaining very heavy components. This study discusses some of the key design aspects of sleeve bearing design for high-torque and low-speed propulsion motor applications. Furthermore, the conditions of variable slope tests are examined to prevent oil leakage from the bearing lip seal on the test rig.