• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.561-562
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.57-58
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• 2005

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1137-1142
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• 2010

This study proposes a guideline of a green roof system suitable for the local environment by verifying the growth of Zoysia japonica in a shallow, extensive, green roof system under rainfed condition. The experimental soil substrates into which excellent drought tolerance and creeping Z. japonica was planted were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios(SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$). The plant height, green coverage ratio, fresh weight, dry weight and chlorophyll contents of Z. japonica were investigated. For the soil thickness of 15cm, the plant height of Z. japonica was significantly as affected by the soil mixing ratio and it was shown in the order SL= $P_4P_4L_2$ < $P_7P_1L_2$ = $P_5P_3L_2$ < $P_6P_2L_2$. For the soil thickness of 25cm, the plant height was increased in order to SL < $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ < $P_4P_4L_2$. The green coverage ratio was not observed by soil the mixing ratio or soil thickness. However, the green coverage ratio was 86~90% with a good coverage rate overall. The chlorophyll contents of Z. japonica were not significantly affected by the soil mixing ratio in the soil thickness of 15cm, but were higher in the natural soil than in the artificial soil at 25cm soil thickness. The fresh weight and dry weight of Zoysia japonica were heavier in the 25cm thickness than in the 15cm thickness and in the artificial soil mixture than in the natural soil. The result indicated that the growth of Zoysia japonica was more effective in the 25cm soil thickness with artificial soil than in the 15cm soil thickness with natural soil in the green roof system under rainfed condition.

• Elastomers and Composites
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• v.48 no.2
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• pp.94-102
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• 2013

Characteristics of rubber mixture were evaluated in order to find the optimum mixing conditions of compounds containing silica and silane at various temperatures. With different mixing temperatures of 105, 120, 130, 140 and $160^{\circ}C$, the viscosity of the compound mixed at $105^{\circ}C$ showed a very high viscosity value. Compounds mixed the temperature range from at $120^{\circ}C$ to $140^{\circ}C$ showed lower viscosity than the compound mixed at $105^{\circ}C$. However, the difference was found to be small in those temperature ranges. On the contrary, at the mixing temperature of $160^{\circ}C$, the viscosity of compound increased again. Through the physical and dynamic observations, it was verified that at the mixing temperature below $120^{\circ}C$ only insufficient silica-silane reaction has been obtained. In addition, with the elevated mixing temperature of $160^{\circ}C$, Cross-linking occurred during mixing by the sulfur contained in coupling agent. In the temperature ranges from $120^{\circ}C$ to $140^{\circ}C$, because of the fast coupling reaction at higher temperature, it was thought to be more advantageous during reaction even though the trend of viscosity and dynamic mechanical property was not clear.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.3
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• pp.233-242
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• 2011

This study aims to evaluate the applicability of high-strength concrete mixed with blast furnace slag to shield segment lining in order to improve its performance and economic efficiency. Especially, it was also intended to derive the optimum replacing ratio of ground granulated blast furnace slag to ordinary cement as well as the optimum steam curing condition for shield segment concrete with the design strength of 60 MPa. From a series of experiments, the condition of 50% replacement of ordinary cement by ground granulated blast furnace slag and unit water content of 125 kg/$m^3$ was proposed as the optimum mixing condition. Comparing with standard curing conditions, it was also possible to expect approximately 110~442% strength improvement of concrete by steam curing in the same mixing condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.2
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• pp.42-53
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• 2009

Gas turbine engine simulation program has been developed. In compressor and turbine, 2-D NS implicit code is used with k-$\omega$ SST turbulent model. In combustor, 0-D lumped method chemical equilibrium code is adopted under the limitations, the products are only 10 species of molecular and air-fuel is perfectly mixed state with 100% combustion efficiency at constant pressure. Fluid properties are shared on interfaces between engine components. The outlet conditions of compressor have been used as the inlet condition of combustor. The inlet condition of turbine comes from the compressor The back pressure in compressor outlet is transferred by the inlet pressure of turbine. Unsteady phenomena at rotor-stator in compressor and turbine is covered by mixing-plane method. The state of engine can be determined only by given inlet condition of compressor, outlet condition of turbine, equivalence ratio and rotating speed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.5
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• pp.79-89
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• 2014

This study was carried out to provide basic information to improve the surrounding ecosystems with benefit analysis and monitoring in cut slopes following establishment of a test construction to improve ecological environment in slopes of an expressway. Field tests from October 2012 to May 2013 were conducted in Seosejong IC and Shinyang IC. In order to improve the view of slopes, soil condition is an important factor. The earth slope, it is possible to introduce directly the plant. Stable construction method was applied, another foundation for planting is necessary. The mixing ratio of the seeds according to the experimental results, the difference was found at an early stage plants in Site I (Seosejong IC). Trees were planted on terraced structures were well coordinated and pictures. The growth of planted trees was good in Site II (Shinyang IC). Due to the use of plants in the landscape will continue to change. Thus, long-term monitoring and landscape analysis will be needed.

• Journal of Powder Materials
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• v.19 no.5
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• pp.373-378
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• 2012

Sintered bulks of $ZrO_2$ nanopowders were fabricated by magnetic pulsed compaction (MPC) and subsequent two-step sintering employed in this study and the formability effects of nanopowder on mixing condition, pressure and sintering temperature were investigated. The addition of PVA induced and increase in the formability of the sintered bulk. But cracked bulks were obtained on sintering with addition of over 10 wt% PVA due to generation of crack during sintering. The optimum compaction pressure during MPC was 1.0 GPa and mixing conditions included using 5.0 wt% PVA. The optimum processing condition included MPC process, followed by two-step sintering (first at 1000 and then at $1450^{\circ}C$). The sintered bulks with the diameter of 30 mm under these conditions were found to have non crack, ~99% density.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.427-434
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• 2000

Hydraulic conductivity of soil-cement was measured as a function of some selected construction variables that are often encountered in practice. They are initial (or compaction) water content, delayed compaction after mixing, and repeated freezing and thawing. Sandy and clayey soils were used. The hardening agent used was a cement based soil stabilizer consisting of 80% of ordinary Portland cement and 20% of a combination of supplementary materials. Hydraulic conductivity of soil-cement with varying initial water content was, in trend, similar to that of compacted clay. Hydraulic conductivity of soil-cement decreased with increasing initial water content and reached its minimum when compacted wet of optimum water content. Pore size distributions of soil cement at different initial water contents were analyzed using mercury intrusion porosimetry. The analysis showed that dryer condition led to the formation of larger pores with lesser total pore volume; smaller pores with larger total pore volume at wetter condition. Hydraulic conductivity of soil-cement increased by orders in magnitude when specimen underwent delayed compaction of longer than 4 hours after mixing and repeated freezing and thawing.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.691-696
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• 2017

An experimental study on engine performance and emission characteristics for bio-alcohol fuels considered as RFS fuel. The Bio-alcohol fuel were mixed ethanol and butanol and used in a 1.8 liter mpi engine. The efficiency of the BSFC is excellent in the maximum torque operation condition and the part load operation condition. As the bio-alcohol mixing ratio increased, the lambda <1 and ignition timing advanced $5^{\circ}CA$. As the mixing concentration increased, NOx emission increase and $CO_2$ emission decreased.