• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.67-73
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• 1994

The gas holdup and volumeteric liquid phase mass transfer coefficient with the variation of the concentration of CMC aqueous solution, gas velocity, diameter and area of the draught tube were investigated. As the results of the experiments, the gas holdup and volumetric liquid phase mass transfer coefficient decreased with decreasing the concentration of CMC aqueous solution, increased with increasing the gas velocity and increased with increasing the circulated area ratio of the draught tube.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.2
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• pp.49-58
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• 1994

A study on the performance of a Diesel engine with various intake gas compositions other than that of air are performed experimentally. In this study, the concentrations of each of oxygen, nitorgen, carbon dioxide, and argon are changed and their effects on the performance of the engine are investigated parametrically. The experiments are performed at constant engine speed condition, and main measured parameters are cylinder pressure, intake gas compositions, fuel consumption rate. Increase of oxygen concentration up to 24% improved the performance of the engine generally. The adverse effect was observed when the oxygen concentration was increased over 24%. Increase of carbon dioxide concentration degraded the performance of the engine, mainly due to the lower specific heat ratio of carbon dioxide. Adding argon gas to the intake gas improved the overall performance. Finally, it is found that two most influencing factors affecting the performance of the Diesel engine in this study of intake gas composition variation are ignition delay and specific heat ratio of the intake gas.

• Tribology and Lubricants
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• v.23 no.6
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• pp.261-265
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• 2007

Carbide-derived carbon coating has been synthesized by low temperature treatment of TiC disk with $H_2/Cl_2$ mixture gases. A variety of physical measurements indicated that Ti was extracted and carbon layer was formed by exposure of $Cl_2$ gas. The $I_D/I_G$ ratio increased with increasing $Cl_2$ gas concentration. Wear coefficient and frictional coefficient varied with $Cl_2$ gas concentration. When the $Cl_2$ gas concentration decreased to 3.3 vol%, the friction coefficient approach a minimum. The results showed that degree of graphite crystallinity and variation of porosity due to the $Cl_2$ gas content were responsible for different tribology performance.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1651-1656
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• 2003

The present study has been conducted to analytically investigate the thermal control performance of variable conductance heat pipe(YCHP) with axial grooves. The condenser port of the YCHP is occupied by a inert gas in which the concentration of gas is varied with the operation temperature and the heat transport capacity is thus varied with the operating temperature due to the variation of inert gas concentration. In this study, numerical evaluation for the thermal control of the YCHP with axial grooves is made from the 1st order diffusion model that considers the diffusive expansion of inert gas by concentration gradient. Ammonia is used as a working fluid and Nitrogen as a control gas in the Aluminum tube. As a result, the thermal performance of YCHP based on diffusion model has been compared with that of YCHP from flat front model. Additionally, it is found that the concentration of inert gas is distributed in the condenser region of YCHP with axial grooves.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.36-44
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• 2001

In case of low odor level, accident probabilities are very high Otherwise, when the odorant concentration is too high, the deterioration of pipeline and governor facilities and the environmental problems may occur. Odorants fade in the pipeline and other equipment due to physical and chemical adsorption and reactions with odorant and materials. So, it is very important to maintain odorant concentration properly In this study, the current status of odorization technologies has been reviewed. And the characteristics of small odorant system have been analyzed. In case that the small odorant system Is introduced in our country, this paper is proposed the feasible management plan and showed feasibility results through the analysis of current available technology.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.896-902
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• 2009

EGR is applied in order to lower temperature of combustion chamber by using the specific heat of carbon dioxide in engine exhaust gas. However, the problem of EGR system in diesel engine is high PM concentration. Combined EGR system can be reduced it by mixing exhaust gas of gas engine into the intake air of diesel engine. This experimental study was designed for EGR system for both engines use. The results of EGR experimental study by using diesel engine and gas engine are as follows. 1) The pressure of combustion and rate of heat release decreased. 2) The specific fuel consumption increased. But, up to middle load, it little increased. 3) NO concentration has decreased up to 50% in almost all combustion area. 4) The variation of the PM concentration at low load is not so seen. But at high load, PM increased rapidly when concentration of oxygen is decreased and most of it caused the increasing of Dry Soot.

• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.18-23
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• 2014

The BTEX contamination of soil around gas station in Korea was investigated in 53 gas stations in 2013 by official test method on soil pollution. Each gas station was divided into oil tank area, line area, and surrounding area. The concentration of BTEX in 1066 sites of 53 gas stations was N.D.~ 3437.36 mg/kg. The order of average concentration for area was as follows: line area ($20.91{\pm}144.79mg/kg$) > tank area ($15.11{\pm}110.08mg/kg$) > surrounding area ($10.79{\pm}111.40mg/kg$). It was the number of sampling site exceeding regulatory levels at surrounding area the most at all. The average concentration of xylene was the highest, while that of ethylbenzene was the lowest.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.649-659
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• 2018

In this study, after operational data for a landfill gas power plant were collected, the methane gas concentration was predicted using a deep learning method. Concentrations of methane gas, carbon dioxide, hydrogen sulfide, oxygen concentration, as well as data related to the valve opening degree, air temperature and humidity were collected from 23 pipeline bases for 88 matches from January to November 2017. After the deep learning model learned the collected data, methane gas concentration was estimated by applying other data. Our study yielded extremely accurate estimation results for all of the 23 pipeline bases.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.339-342
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• 2004

It is research about special quality of ozone gas concentration and dissolved ozone concentration that show according to change of flow rate when liquefied ozone gas in water. If increase flow rate of ozone gas, ozone concentration increases being proportional and amount to fixed flow rate, dissolved ozone concentration was measured low. When ozone concentration How rate 1000 [ppm], dissolved ozone concentration smelted to flow rate 1.5[Q] for 28 [min] is $0.1740{\sim}0.8020[mg/l]$. Could know that half-life is most short by 3 minutes 8 seconds in flow rate 1.5 [Q]. And ozone smelted 20 minutes later after half-life measurement became disjointing all.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.107-113
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• 2011

This study was performed for the application of the exposure limit in work field and the relative noxious gas concentration was estimated by using a miniature ship. The noxious gas concentration about light and shade number distribution of measuring subject field was estimated by using floating visualization image from a miniature ship in a large wind tunnel. About the concentration estimation, the correlation of concentration distribution drawn from the existing experimental results was used, the estimation result satisfied LTEL standard.