• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.80-87
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• 2003

Air partial pressure ratio and inlet air mass flow are influenced by water vapor and gaseous fuel in mixture on Compressed Natural Gas (CNG) engines. In this paper, the effects of the water vapor and the gaseous fuel that change the air mass flow and the air-fuel ratio are studied. Effective air mass ratio is defined as the air mass flow divided by mixture mass flow, and also it is applied to the estimation of the inlet air mass flow and the air-fuel ratio. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the CNG engines. The experimental results for the CNG engine show that estimation of the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal mode.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.95-99
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• 2008

Halon was known as a cause of the ozone layer destruction. In 1987, it was designated as one of the ozone-layer-destroying materials in the Montreal Protocol. Therefore substitutes of Halon agent has been developed including inert gas extinguish system, which is one of the most widely used fire extinguishing system. This study intended to increase the efficiency of inert gas extinguishing agent by using inert gas additives. As IG-541 shows high extinguishing power, the experiment was performed to measure the effects of gaseous additives to it. Cup-burner fire extinguishing apparatus was used with n-Heptane fuel. Among many of pure inert gaseous agents, Helium showed the most excellent extinguishing power. When Helium was added to IG-541, fire extinguishing power was increased and the concentration of oxygen in chimney also risen. By adding Helium to IG-541, the effectiveness of inert gas fire extinguishing system is able to be increased.

• Progress in Superconductivity and Cryogenics
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• v.21 no.3
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• pp.47-50
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• 2019

The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.166-171
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• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.151-151
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• 2012

A new plasma process, i.e., the combination of PIII&D and HIPIMS, was developed to implant non-gaseous ions into materials surface. HIPIMS is a special mode of operation of pulsed-DC magnetron sputtering, in which high pulsed DC power exceeding ~1 kW/$cm^2$ of its peak power density is applied to the magnetron sputtering target while the average power density remains manageable to the cooling capacity of the equipment by using a very small duty ratio of operation. Due to the high peak power density applied to the sputtering target, a large fraction of sputtered atoms is ionized. If the negative high voltage pulse applied to the sample stage in PIII&D system is synchronized with the pulsed plasma of sputtered target material by HIPIMS operation, the implantation of non-gaseous ions can be successfully accomplished. The new process has great advantage that thin film deposition and non-gaseous ion implantation along with in-situ film modification can be achieved in a single plasma chamber. Even broader application areas of PIII&D technology are believed to be envisaged by this newly developed process. In one application of non-gaseous plasma immersion ion implantation, Ge ions were implanted into SiO2 thin film at 60 keV to form Ge quantum dots embedded in SiO2 dielectric material. The crystalline Ge quantum dots were shown to be 5~10 nm in size and well dispersed in SiO2 matrix. In another application, Ag ions were implanted into SS-304 substrate to endow the anti-microbial property of the surface. Yet another bio-application was Mg ion implantation into Ti to improve its osteointegration property for bone implants. Catalyst is another promising application field of nongaseous plasma immersion ion implantation because ion implantation results in atomically dispersed catalytic agents with high surface to volume ratio. Pt ions were implanted into the surface of Al2O3 catalytic supporter and its H2 generation property was measured for DME reforming catalyst. In this talk, a newly developed, non-gaseous plasma immersion ion implantation technique and its applications would be shown and discussed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.33-40
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• 2021

The objective of this work is to prove a possibility of void f illing through a carbonation f or the purpose of improving the quality of recycled aggregate. Carbonation can permanently immobilize CO2, which is a greenhouse gas, and thus provides additional benefit on environment. In this work, recycled fine aggregate was reacted using gaseous CO2 and supercritical CO2(scCO2) in a closed chamber, and the changes in physical properties of the recycled f ine aggregate bef ore and af ter carbonation were analyzed using the apparent density, skeletal density, pH, and FE-SEM measurements. Thereafter, a mortar specimen was prepared and a compressive strength was measured. According to the experimental results, it was found that the increase in the apparent density and the true density was higher by the reaction with scCO2, which was conducted at high temperature and high pressure compared to the reaction with gaseous CO2. In addition, the pH of the eluted water was found to have a larger initial decrease than that observed with samples from reaction by gaseous CO2. The shape and amount of calcium carbonate crystals were also found to be larger than that from gaseous CO2. The increase in compressive strength was the largest when using recycled fine aggregate reacted with scCO2. It was clear that quality improvement of recycled fine aggregate was higher with scCO2 than with gaseous CO2.

• Journal of the Korean Ceramic Society
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• v.15 no.2
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• pp.85-88
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• 1978

Influence of cooling atmosphere on the whiteness in white portland cement was studied. The effective composition of gaseous medium of cooling atmosphere is desirable less than 0.5% of $O_2$ and 0.5~1.5% of CO. When theclinker is quenched in nitrogen atmosphere, the color of clinker becomes bright pink. In a weakly reducing gaseous medium or vacuum, the absence of oxygen brings defects in crystal and transformation in the coordination of iron, and as a result, whiteness is raised.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.178-182
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• 2004

Numerical analysis of a gaseous jet submerged in a liquid environment was carried out using the volume of fluid(VOF) method to simulate the kinematics of the gas-liquid interface. Two nozzle geometries were tested, one for Fanno tube and the other for converging diverging nozzle. Commercial code was used for the present calculation. Transient behavior of a gaseous jet since its start showed periodic nature of the jet, which was also observed in previous measurements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.191-194
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• 1996

Maxwell displacement current clearly shows the onset of a first order phase transition from gaseous to gaseous-fluid phase, and polar ordering of liquid molecules in the solid phase coexisting with fluid. For further monolayer compression in the fluid/solid phase transition, the condensation of domains was suggested.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.5
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• pp.219-227
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• 2002

This study has been performed to investigate the effect of $CO_2$ content on the growth characteristics of the compound layer, porous layer and corrosion characteristics of carbon steels after gaseous nitrocarburizing in $70%-NH_3-CO_2-N_2$ at $580^{\circ}C$ for 2.5 hrs. The results obtained from the experiment were the thickness of the compound and porous layers increased with increasing $CO_2$ contents. At the same fixed gas composition the thickness of the compound and porous layer increased with increasing carbon content of the specimens. X-ray diffraction analysis showed that compound layer was mainly consisted of ${\varepsilon}-Fe_{2-3}(N,C)$ and ${\gamma}^{\prime}-Fe_4N$ as the increased with $CO_2$ contents in atmosphere, compound layer was chiefly consisted of ${\varepsilon}-Fe_{2-3}(N,C)$ phase. With increasing $CO_2$ content and total flow rate in gaseous nitrocarburizing, the amount of ${\varepsilon}-Fe_{2-3}(N,C)$ phase in the compound layer was increased. The current density of passivity decreased with increasing $CO_2$ content due to the development of porous layer at the out most surface of ${\varepsilon}-Fe_{2-3}(N,C)$.