• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.112-115
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• 2005

The objectives of this study are to evaluate the dynamic fracture toughness of advance glass ceramics(MACOR glass-filled ceramic, Corning Glass Works) for dome port cover of the ramjet. Static and dynamic fracture toughness tests are performed using strain gage method in the variation of notch radii.

• The Journal of Information Systems
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• v.19 no.4
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• pp.167-181
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• 2010

Although This study was designed to evaluate internet communities based on knowledge creation and learning. To do so, we created and tested our research model, by using selected 20 different knowledge communities. Using the K-Means Clustering techniques, we found different characteristics and evaluated these characteristics by the criterion. The results of discriminant analysis suggested 4 different models such as 'Search Engine,' 'Open Communities,' 'Specialty Communities,' and 'Activity Communities.' The results of this study indicated that it can cover some reasons for development process of knowledge communities and that it can also create a strategic framework for practical use of knowledge communities.

• Journal of the Korean Society of Industry Convergence
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• v.11 no.2
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• pp.65-70
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• 2008

This study presents gas turbine cooling blade by using experimental and numerical works. The review cover researches related to cooling channels using finite element method in rotating blade. Also, the film cooling device and the heat transfer of the external surface of the blade are included. In addition, several methods to be used for the design of the blade, numerical method and experimental techniques are introduced. This work will contribute to improving the manufacturing of engine and the efficiency of gas turbine engines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.107-110
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• 2008

The test range for turbopump and gas generator coupled test was determined considering the engine system test area which cover the qualification and development. Based on the test range, we determined the required loss coefficient for the throttle valves and lines.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.260-266
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• 2005

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The lift-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1461-1466
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• 2000

This paper investigates the noise reduction scheme in tractor cabin by using various steps of experiment. The experiments were performed in the field as well as in the lab to facilitate the detail test procedure. Some of the test results were compared with computational results. Several noise sources and paths were identified including the engine compartment (cooling fan and timing gear cover), hydraulic system and its components (hoses, tubes and there mount) and structural characteristics of the cab, window, mounting bracket and machine frame including steps. Throughout the several design changes, cab noise level was reduced from 80.2dBA to 74.8dBA.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.551-556
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• 2004

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The life-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.35-49
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• 2014

In order to understand the impacts of surface characteristics and the distance from the urban heat island center to suburban areas on the mean night time air temperature, we analyzed GIS and AWS observational data. Spatial distributions of mean night time air temperature during the summer and winter periods of 2004-2011(six years) were utilized. Results show that the temperature gradients were different by distance and direction. We found high correlation between mean night-time air temperature and artificial land cover area within 1km and 200m radii during both summer(R=0.84) and winter(R=0.78) seasons. Regression models either from 1km and 200m land surface data explained the distribution of night-time temperature equally well if the input data had sufficient resolution with detailed attribute including building area and height.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.47-51
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• 2014

This paper is to analyze and study the fire examples in respect of intake and exhaust, alternator tuning and inflow of inflammables on exhaust part in a car. In the first example, the driver diverted the intake and exhaust system for tuning of a car. Stopping a car to rest for moment, the flammable styrofoam scrap go into exhaust pipe that installed with exhaust manifold newly. It certified the fact that catched fire gradually, furthermore enlarged the fire by leaking fuel. In the second example, the driver enlarged the generator performance to divert the audio system in side room., it knew the fact that the electric wiring connected with generator gave the cause of outbreak a fire by overheating. In the third example, the serviceman replaced the engine oil using funnel-shaped, he put the a bottle of plastic pat onto engine cover carelessly. Consequentially, it found the fire occurrence in the engine room. Therefore, the driver never divert the intake and exhaust and generator construction of a car abnormally. Also, repairing and inspecting a car, the serviceman have a care to not occur the fire by inflammables.

• Advances in aircraft and spacecraft science
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• v.7 no.6
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• pp.537-551
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• 2020

Investigation of leading edge impingement cooling for first stage rotor blades in an aero-engine turbine, its effect on rotor temperature and trailing edge wake loss have been undertaken in this study. The rotor is modeled with the nozzle for attaining a more accurate simulation. The rotor blade is hollowed in order for the coolant to move inside. Also, plenum with the 15 jet nozzles are placed in it. The plenum is fed by compressed fresh air at the rotor hub. Engine operational and real condition is exerted as boundary condition. Rotor is inspected in two states: in existence of cooling technique and non-cooling state. Three-dimensional compressible and steady solutions of RANS equations with SST K-ω turbulent model has been performed for this numerical simulation. The results show that leading edge is one of the most critical regions because of stagnation formation in those areas. Another high temperature region is rotor blade tip for existence of tip leakage in this area and jet impingement cooling can effectively cover these regions. The rotation impact of the jet velocity from hub to tip caused a tendency in coolant streamlines to move toward the rotor blade tip. In addition, by discharging used coolant air from the trailing edge and ejecting it to the turbines main flow by means of the slot in trailing edge, which could reduce the trailing edge wake loss and a total decrease in the blade cooling loss penalty.