• Proceedings of the KSME Conference
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• 2001.06d
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• pp.447-452
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• 2001

Quenching phenomena of hemispherical downward facing convex surfaces with narrow gaps have been investigated experimentally. Experiments employed test sections having 1 and 2 mm in gap thickness and 1 atm in system pressure. From interpretations of the temperature and the heat flux history, it was found that the flooding inside the gap was restricted by CCFL phenomena and quenching process was propagated from lower to upper region of the internal copper shell. The ratio of the maximum heat fluxes at 1 mm to 2mm in gap thickness was the almost same that obtained by steady state experiments. The quenching scenario of the hemispherical downward facing surface with narrow gap has been suggested.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.80-86
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• 2002

To reduce the nation from facing increasing industrial disasters following the grave foreign exchange crisis in 1997, this thesis compared inside with outside of the current country safety manager system, presented way about introduction to comprehensive safety management measures.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.129-135
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• 2002

The present article deals with the measurement and the numerical calculations far the temperature distribution near the facing of the lockup clutch. The rotating telemetry system is Introduced for the estimation inside high-speed torque converter For the numerical calculation, the effect of the convective heat transfer is considered as well as the conduction to the solid. The estimation shows that the oil temperature near facing rapidly rises as the lockup clutch is engaged. The numerical results shows good agreements with the experimental values for the maximum temperature near the facing of the lockup clutch.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.1-9
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• 2003

This paper discusses on recent topics on harbour tranquility base on ship motions. Harbour tranquility is mainly discussed only wave height inside a harbour at the first research period. In these twenty years, researches to improve harbour tranquility have been focused on ship motions to reduce mooring troubles facing to open seas. (omitted)

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.53-60
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• 2013

A new type of reinforced earth wall(REW) system is developed with vegetated facing which provides proper environment for long-term vegetation and also applicable to high retaining wall system. Vegetated retaining wall is a green alternative for retaining walls and an effective way to reduce heat island effect than conventional block or concrete systems. Several construction sites using vegetated facing is observed to monitor adaptation state of vegetation and estimate surface temperature of wall facing over two years. It was observed that a number of plants including Siberian chrysanthemum adapt well to the inside of the facing blocks because vegetation bag helps to keep a proper condition for vegetation. According to the results using thermographic camera, average surface temperature of vegetated facing is higher for all ranges of coverage ratio of vegetation. The increment of average surface temperature of vegetated facing is larger than that of non-vegetated facing when the air temperature rises, and vice versa.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.85-92
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• 2004

As a research to develop a SCRAM jet engine is actively conducted, a necessity to produce a high-enthalpy flow in a laboratory is increasing. In order to develop the SCRAM-jet engine, stabilized combustion in a supersonic flow-field should be attained, in which a duration time of flow is extremely short. Therefore, a mixing process of breathed air and fuel, which is injected into supersonic flow-fields is one of the most important problem. Since, the flow inside SCRAM jet engine has high-enthalpy, an experimental facility is required to produce such high-enthalpy flow-field. In this study, a detonation-driven shock tunnel was built and was used to produce high-enthalpy flow. Further-more, SCRAM jet engine model equipped backward-facing step was installed at test section and flow-fields were visualized using color-schlieren technique and high speed video camera. The fuel was injected perpendicular to the flow of Mach number three behind backward-facing step. The height of the step, distance of injection and injection pressure were changed to investigate the effects of step on a mixing characteristic between air and fuel. The schlieren photograph and pressure histories show that the fuel was ignited behind the step.

• Journal of computational fluids engineering
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• v.14 no.1
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• pp.86-95
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• 2009

A kinetic theory analysis is used to study the ultra-thin gas flow field in gas bearings. The Boltzmann equation simplified by a collision model is solved by means of a finite difference approximation with the discrete ordinate method. Calculations are made for flows inside micro-channels of backward-facing step, forward-facing step, and slider bearings. The results are compared well with those from the DSMC method. The present method does not suffer from statistical noise which is common in particle based methods and requires less computational effort.

• Journal of the Korean Society of Costume
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• v.59 no.9
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• pp.26-42
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• 2009

The purpose of this study is to examine how to sew the hem of men's coat which were excavated from the Yeosan Song Clan's tombs that are thought to be formed between the late 15th and the late 16th centuries, findings of the study can be summarized as follows. 1. Andan, or inside facing was used to prevent the hem from being worn or swollen or to make the hem properly arranged. It was generally used for single-layered and cotton-quilted coat for men. Deotdan was used mainly for men's coat having oblique cutting lines and jemuldan for those having straight cutting lines. In single-layed coat for men, the width of andan was widened a little as the times moved from the late 15th to the late 16th century, but in cotton-quilted ones, the width was not significantly changed. 2. Fixing the lining and the upper was used as a method to prevent the lining of men's coat from being pushed out or the hem of the clothes from being swollen. The method was generally used for double-layered, cotton and cotton-quilted coat for men. The double back-stitching was usually used for double-layered and cotton coat for men and the broad-stitching for Cotton-quilted ones. 3. Among men's coat, those whose siding was partially opened were less spare in the lower end than those whose siding was wholly opened. For this reason, the former clothes were more likely to have the tip of the siding easily torn. To solve this problem, overhand knotting 1, overhand knotting 2 and lotus-flower knotting strings were used for men's coat whose siding was partially opened. Among the three types, lotus-flower knotting was most elaborate in form. For men's coat, overhand knotting became gradually replaced by lotus-flower knotting as the times moved from the late 15th to the late 16th century.

• Journal of Environmental Impact Assessment
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• v.31 no.5
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• pp.334-342
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• 2022

The stringent air environment conservation act forced to build an indoor dome for coal storage. However, it causes some problems due to accumulation of fly ash and harmful substances inside. To solve this problem, this study analyzed the pattern of internal airflow and the amount of ventilation for an indoor coal yard. Overall, the airflow inside the indoor coal yard tended to move to the southwest facing the mountain. In addition, sea-breeze was blowing from the northern louver window facing the sea, where airflow was flowing in. The total flow rate flowing into the indoor coal yard was 918,691 m³/h, and the number of natural ventilation per hour was 0.6 times. Therefore, it is proposed to install a forced ventilation device at the location where internal air flow is concentrated.

• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.168-173
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• 1998

A numerical analysis of axisymetric backward facing step main nozzle flow in air jet loom has been accomplished. To obtain basic design data for an optimum main nozzle for an air-jet loom and to predict the transonic/supersonic flow, a characteristic based upwind flux difference splitting compressible Navier-Stokes method has been used. The wall static pressure of the main nozzle and the flow velocity changes in the nozzle tube were analyzed by changing air tank pressures and acceleration tube lengths. The flow inside the nozzle experiences double choking one at the needle tip and the other at the acceleration tube exit at tank pressures over $4kg_f/cm^2$. The tank pressure $P_t$ leading to the critical condition depends on the acceleration tube length; i.e, $P_t$ is higher for longer acceleration tubes. The $P_t$ value required to bring the acceleration tube exit to the critical condition is nearly constant regardless of acceleration tube length. The round needle tip shape might lead to less total pressure loss when compared with step shape.