• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.18-21
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• 2008

Acoustic design parameters of a half-wave resonator are studied experimentally for acoustic stability in a model combustor. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of damping factor and sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. The diameter and the number of a half-wave resonator, its distribution are selected as design parameters for optimal tuning of the resonator. Acoustic damping capacity increases as the resonators with diameter increases. The optimum number of resonators or the optimum open-area ratio decreases as boundary absorption decreases.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.103-110
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• 2020

The DMM (Deep mixing method) is a construction method in which an improved pile is installed in the soft ground by excavation ground using an auger and then mixing ground stabilizer with soil. Improved pile installed in the soft ground by the DMM may have different compressive strength depending on the properties and characteristics of the soil. In the previous study, laboratory tests were performed on the ground stabilizer for the DMM developed by using the ash of the circulating fluidized bed boiler as a stimulator for alkali activation of the blast furnace slag. And the test results were analyzed to derive the correlation between the unit weight of binder (γ_B) and the uniaxial compressive strength (q_u). In this study, comparative reviews were conducted on the correlations derived from the same laboratory tests on soil material collected from the Saemangeum area and the stability of the site was evaluated by analyzing the test results performed at the site. As a result, the clay collected from the Saemangeum area satisfies the correlation between the unit weight of binder (γ_B) and the uniaxial compressive strength (q_u) derived from the previous study. And the result of the test at the field showed a higher uniaxial compressive strength than the standard strength at the field, indicating excellent stability.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.478-485
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• 2015

The aim of this study is to analyze the combustion and thermal properties in order to establish baseline data for the fire safety evaluation of domestic timbers. The combustion properties such as heat release rate, total heat release, gas yield, and mass loss were analyzed by the method of cone calorimeter test and thermogravimetry (TGA). Thermal decomposition temperatures of the specimens by TGA were recorded as $359.83^{\circ}C$ for White pine, $359.80^{\circ}C$ for Red-Leaved Hornbeam, $363.14^{\circ}C$ for Carolina poplar, $358.59^{\circ}C$ for Konara oak, and $362.11^{\circ}C$ Sargent cherry. Red-Leaved Hornbeam showed the highest value of heat release rate, but, Carolina poplar wood showed the lowest value. In case of the total heat release, Red-Leaved Hornbeam wood showed the highest value and Carolina poplar wood showed the lowest one. The gas analysis results showed that Sargent cherry wood had the lowest value of 0.021, and Konara oak had the highest at 0.031 in the $CO/CO_2$. The minimum value of mass reduction was recorded as 87.57% for Sargent cherry, but, on the other hand, it was 95.03% for Konara oak. There was a correlation between the gas generation of CO and $CO_2$, and combustion behavior of woods. These results are expected to be usful for providing a fundamental guideline with the fire safety of wood use in interior applications.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.165-174
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• 2004

In order to simultaneously vitrify the ion exchange resin(IER) and combustible dry active waste(DAW) generated from Korean nuclear power plants, a vitrification pilot test was conducted using an induction cold crucible melter(CCM) . The energy necessary for startup of the glass using a Ti-ring was evaluated as about 290 kWh. The power supplied from a high frequency generator to melt the glass properly was ranged from 160 to 190 kW without any interruption. When the mixture of the IER and DAW was fed into the CCM, the concentration of CO was lowered up to 1/40 compared to feeding the IER solely. It may be caused by the DAW which can produce about 1.8 times higher heat compared to the IER. When the swelling phenomenon occurred in the glass melt, the concentration of $NO_2$, oxidizing gas, was higher than NO, reducing gas. Total feed amounts of the IER and DAW were 368 and 751 kg, respectively. And then, about 74 of volume reduction factor was achieved.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.19-29
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• 2016

The purpose of this study is to analyze the combustion and thermal properties in order to establish baseline data for the fire safety evaluation of imported wood. The combustion properties such as heat release rate, total heat release, gas yield, and mass loss were analyzed by the method of cone calorimeter test according to KS F ISO 5660-1 and thermogravimetric analysis (TGA). Analyzed species are five kinds of species as Merbau, Mempening, Garo Garo, Malas, and Dillenia. The heat released rate values showed the highest value of Malas as $375.52kW/m^2$, and Dillenia showed the lowest value as $133.30kW/m^2$. The data values were confirmed in the following order: Malas > Mempening > Garo Garo > Merbau > Dillenia. In case of the total heat release, it was measured in the following order: Mempening > Malas > Garo Garo > Merbau > Dillenia. The gas analysis results were that Dillenia showed the highest value of 0.034. Also, Mempening and Malas showed the lowest at 0.020 in the $CO/CO_2$. Min of mass reduction was shown as 74.79% Sargent cherry, on the other hand, Malas had a 83.52%. It showed a correlation between and of the CO and $CO_2$ generation and combustion characteristics of wood. The thermal decomposition temperature of the wood in the TGA were as follow that Merbau $348.07^{\circ}C$, Mempening $367.57^{\circ}C$, Garo Garo $350.59^{\circ}C$, Malas $352.41^{\circ}C$, Dillenia $364.33^{\circ}C$. The aim of this study is to determine the combustion properties of imported wood according to ISO 5660-1. And, based on the results of this study, we would proceed with further research for improving the fire safety of wood for construction.

• Journal of the Korean Geosynthetics Society
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• v.18 no.2
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• pp.37-44
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• 2019

The compressive strength of the soil stabilizer in the deep mixing method (DMM) depends on kinds of soil, particle size distribution, and water content. Because of this, Laboratory test has to perform to estimate the unit weight of binder to confirm the satisfaction of the design strength. In this study, uniaxial compression strength was measured by mixing the soil stabilizers developed in the previous study with clay in Busan, Yeosu, and Incheon area. And the strength enhancement effect was evaluated comparing with blast furnace slag cement (BFSC). Also, the relationship between the unit content of binder and uniaxial compressive strength was investigated in order to easily calculate the unit weight of binder required to ensure the stability of the ground at the field. As the results of the analysis, the relationship between the unit content of binder and the uniaxial compressive strength are ${\gamma}_B=(108.93+0.0284q_u){\pm}35$ when W/B is 70%, and ${\gamma}_B=(122.93+0.0270q_u){\pm}40$ when W/B is 80%.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.267-271
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• 2013

Test bed studies with highly efficient amine $CO_2$ solvent (KoSol-4) developed by KEPCO research institute were performed. For the first time in Korea, evaluation of post-combustion $CO_2$ capture technology to capture 2 ton $CO_2$/day from a slipstream of the flue gas from a coal-fired power station was performed. Also the analysis of solvent regeneration energy was conducted to suggest the reliable performance data of the KoSol-4 solvent. For this purpose, we have tested 5 campaigns changing the operating conditions of the solvent flow rate and the stripper pressure. The overall results of these campaigns showed that the $CO_2$ removal rate met the technical guideline ($CO_2$ removal rate: 90%) suggested by IEA-GHG and that the regeneration energy of the KoSol-4 showed about 3.0~3.2 GJ/$tCO_2$ which was, compared to that of the commercial solvent MEA (Monoethanolamine), about 25% reduction of regeneration energy. Based on these results, we could confirm the good performance of the KoSol-4 solvent and the $CO_2$ capture process developed by KEPCO research institute. And also it was expected that the cost of $CO_2$ avoided could be reduced drastically if the KoSol-4 is applied to the commercial scale $CO_2$ capture plant.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.391-396
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• 2016

The absorption efficiency of amine $CO_2$ absorbent (KoSol-5) developed by KEPCO research institute was evaluated using a 0.1 MW test bed. The performance of post-combustion technology to capture two tons of $CO_2$ per day from a slipstream of the flue gas from a 500 MW coal-fired power station was first confirmed in Korea. Also the analysis of the absorbent regeneration energy was conducted to suggest the reliable data for the KoSol-5 absorbent performance. And we tested energy reduction effects by improving the absorption tower inter-cooling system. Overall results showed that the $CO_2$ removal rate met the technical guideline ($CO_2$ removal rate : 90%) suggested by IEA-GHG. Also the regeneration energy of the KoSol-5 showed about $3.05GJ/tonCO_2$ which was about 25% reduction in the regeneration energy compared to that of using the commercial absorbent MEA (Monoethanolamine). Based on current experiments, the KoSol-5 absorbent showed high efficiency for $CO_2$ capture. It is expected that the application of KoSol-5 to commercial scale $CO_2$ capture plants could dramatically reduce $CO_2$ capture costs.