• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.6
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• pp.256-262
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• 2018

A great amount of fly ash, which is a waste from a thermal power plant, has not been appropriately recycled until now. Landfill of flay ash causes environmental pollution and enormous economic costs. In this study, manufacturing of architectural ceramic tile was investigated replacing fly ash with clay raw material. The properties of porcelain tile was analyzed after manufacturing porcelain tile with mineral based glaze and fast firing process. In particular, the effect of the fly ash addition on the properties of ceramic tile was investigated by increasing the amount of limestone addition. Porcelain tile with fly ash showed excellent bending strength, water absorption, warping and abrasion resistance. However, a significant decrease in durability was observed through the autoclave test. Addition of limestone increased the water absorption, twisting and hydration expansion of the ceramic tile, but it was confirmed that the durability of the ceramic tile with fly ash was greatly improved. In conclusion, recycled architectural ceramic tiles, which can meet domestic construction standards, could be manufactured with the addition of fly ash and limestone.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2296-2302
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• 2018

Internally plasticized PVC was prepared via chemical reaction of azide PVC and alkynyl group containing castor oil methyl ester. The chemical structure of alkynyl group containing castor oil methyl ester and internally plasticized PVC was characterized with FT-IR and $^1H$ NMR. Properties of internally plasticized PVC, including thermal stability, tensile tests and resistance to extraction in different solvents, was investigated. The results showed that alkynyl group containing castor oil methyl ester, as internal plasticizer of PVC, not only decreased the $T_g$ of PVC from $84.6^{\circ}C$ to $41.6^{\circ}C$ efficiently, but also presented no plasticizer loss in five different solvents. The tensile tests showed that elongation at break and tensile strength of internally plasticized PVC was 353.8% and 18.1 MPa. The internally plasticized PVC has potential application in replacing the traditional PVC material in PVC products with high durability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.16-18
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• 2013

A fire outbreak in a reinforcement concrete structure looses the organism by different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So, concrete reinforcement structure is damaged partial or whole structure system. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. In this study, consider case of investigation methods and repair work in fire damaged structure concrete.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.584-587
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• 2006

An energy generating greenhouse based on fluoropolymer envelope and fresnel lens is proposed. The outstanding properties of the fluoropolymer films make them very suitable for large scale solar applications. Extremely high optical transmission over the whole solar spectrum, combined with mechanical strength, and durability allows us to design a highly optimized greenhouses for both plant growing and energy generation. Systems such as photovoltaic triple junction cells are especially attractive since they have up to 35% efficiency with much less cell material when the sun beam is focused with concentrators such as fresnel lenses. Cooling such devices will enhance the efficiency and provide useful thermal energy that could be further utilized for various applications depending on the local demands. This article introduces the basic ideas and principles of the energy generating greenhouses as a first step towards the actual deployment of such systems under Korean environment.

• New & Renewable Energy
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• v.3 no.4
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• pp.3-7
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• 2007

Graphite/polymer composite bipolar plates for PEMFC are successfully developed, and their typical properties are superior to commercially available ones. Thermal property of the developed bipolar plate was evaluated by dynamic mechanical analyzer, and the results were compared to commercial ones. The specimens were immersed into the deionized water bath at $80^{\circ}$... for 1500hrs to evaluate dimensional stability and durability. Dimension, weight of the specimens as well as extraction conductivity was measured as each 500hrs. Fully molded bipolar plates without any machining or milling were also prepared using a specially developed mold, and they were applied to the fuel cell performance test. Results were compared to the machined commercial bipolar plate.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.191-196
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• 2010

Tungsten-carbide as typical difficult-to-cut material has excellent mechanical properties such as high thermal resistivity, mechanical strength and chemical durability. However, it is next to impossible for tungsten-carbide to be fabricated the needed parts by cutting process. In this study, for establishing the micro fabrication method of tungsten-carbide for micro injection or compression molding core, the investigation on micro cutting characteristics of tungsten-carbide green part which is made by powder injection molding process and easy to cut relatively was performed. For this, micro endmilling experiments of tungsten-carbide green part were performed according to various cutting conditions. Finally, the wear trend of micro endmill and the appearance of micro rib according to feed-rate and cutting depth per step were analyzed through SEM images of micro cutting feature and microscope images of micro tools.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.5-7
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• 2007

Graphite/polymer composite bipolar plates for PEMFC are successfully developed, and their typical properties are superior to commercially available ones. Thermal property of the developed bipolar plate was evaluated by dynamic mechanical analyzer, and the results were compared to commercial ones. The specimens were immersed into the deionized water bath at $80^{\circ}C$ for 1500hrs to evaluate dimensional stability and durability. Dimension, weight of the specimens as well as extraction conductivity was measured as each 500hrs. Fully molded bipolar plates without any machining or milling were also prepared using a specially developed mold, and they were applied to the fuel cell performance test. Results were compared to the machined commercial bipolar plate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.230-231
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• 2013

A fire outbreak in a reinforcement concrete structure looses the organism by different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So, concrete reinforcement structure is damaged partial or whole structure system. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. In this study, consider case of investigation methods and repair work in fire damaged structure concrete.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.962-967
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• 2017

The Diamond-Like-Carbon (DLC) coating is a new carbon-based amorphous material. Carbon ions in the plasma are electrically accelerated and collide with the substrate to form a thin film. This film has similar properties to diamonds such as high surface hardness, low coefficient of friction, corrosion resistance and durability that do not react with acids and bases. Also, since there is no thermal deformation, it can be printed at room temperature. and coated on almost all materials such as paper, polymer, ceramics and various metals even aspheric lens it is possible to mirror surface coating with excellent surface roughness. In this paper, we have analyzed the DLC film formed by Filtered Arc Ion Plating (Filtered AIP) process.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.291-292
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• 2010

In this study, high-strength concrete mixtures were made with blast-furnace slag of 50% and 70% replacement level to evaluate material properties including compressive strength development, adiabatic temperature rise, autogenous shrinkage and chloride-ion migration coefficient. Test results showed that the use of high percentage blast-furnace slag in high-strength concrete can reduce heat of hydration and chloride-ion migration coefficient, result in control thermal cracking and improve durability performance especially under high corrosive environment.