Papers by Author: Woo Teck Kwon

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Authors: Woo Teck Kwon, Soo Ryong Kim, Y. Kim, Yoon Joo Lee, Eun Jin Jung, Won Kyu Park, Sea Cheon Oh
Abstract: β-SiC powder was synthesized directly from silicon sludge with carbon black. Large amount of silicon sludge is generated from Solar Cell industry. In an environmental and economic point of view, recycling silicon sludge is important. In this study, two kinds of silicon sludge were characterized using XRD, SEM/EDS and FT-IR. SiC powder was synthesized by the reaction of ball-milled silicon powder for 3h in vacuum at different temperatures (1350 and 1600). Physical properties of the heat treated SiC have been characterized using a SEM, XRD, Particle size analyzer and FT-IR Spectroscopy.
Authors: Kyung Mok Nam, Yoon Joo Lee, Soo Ryong Kim, Woo Teck Kwon, Hyung Sun Kim, Y. Kim
Abstract: The formation of organic-inorganic hybrid composite with ceramic platelets and polymeric compound can have the higher strength and higher elasticity than metal, which is a nanocomposite with high strength and light weight. Ceramic platelet such as Al2O3 has been used to form organic-inorganic composite material using PMMA as an organic polymer. Bending strength and density of the composites prepared by infiltration and post-warm pressing were measured. FE-SEM and TG analysis were carried out to determine the microstructure of the organic-inorganic composite materials. Bending strengths and densities of the composites prepared by Al2O3 ceramic plate and PMMA after post-warm pressing were ~70MPa and ranged from 2.4 to 2.6, respectively.
Authors: Woo Teck Kwon, Soo Ryong Kim, Y. Kim, Jong Hee Hwang, Vikram V. Dabhade, Tae Wook Yoo, Seong Youl Bae
Abstract: The possible utilization of automobile shredder residue as a fuel in the cement kiln process was investigated. The detailed characteristics of the automobile shredder residues were investigated in terms of it’s chlorine content as a fuel feed and its circulation in cement kiln. For estimation of the chlorine content in the cement kiln system, the Weber model which is one of the circulation material’s forecast model was used. From the results, we estimated the chlorine by-pass rate should be 1 ~ 2 percent, for maintaining the present level of chlorine content’s on the hot-meal of the cement kiln system.
Authors: Woo Teck Kwon, Y. Kim, Soo Ryong Kim, Tae Yeoung Lim
Authors: Woo Teck Kwon, Byung Ik Kim, Y. Kim, Soo Ryong Kim, Sang Wook Ha
Abstract: In this work, the physical & chemical properties of bottom ash generated from power plant are analyzed. Characteristic mortar property and thermal conductivity for building material were investigated with content of added bottom ash. According to the analytic result of bottom ash, chemical compositions of bottom ash is similar to those of fly ash and compressive strength after 7days related to pozzolanic activity shows 2.5N/cm2 and it is confirmed that bottom ash possess a certain amount of moisture activity. Although the fluidity of cement mortar is rapidly decreased with increasing addition of bottom ash, compressive strength for 3 and 7days is increased. The thermal conductivity is not sensitive to the addition of bottom ash.
Authors: Woo Teck Kwon, Soo Ryong Kim, Y. Kim, Yoon Joo Lee, Ji Yeon Won, Tae Gyung Ko, Sea Cheon Oh
Abstract: Characterization of silicon kerf from photovoltaic silicon-wafer production was carried out. Also, SiC powder was synthesized using high purity silicon kerf by varying grinding conditions. With increase of grinding time, surface of the silicon was oxidized to form silicon oxide. Also, it was observed that the unreacted silicon oxide and free silicon amount in the SiC powder increases with an increasing grinding times, even though silicon particle size of the starting material is decreased.
Authors: Soo Ryong Kim, Woo Teck Kwon, Byung Ik Kim, Y. Kim, Sang Wook Ha
Abstract: The effectiveness of bottom ash on the mechanical and physical properties of lightweight cement mortar for fire proofing application is investigated in this study. Bottom ash is well known that it can make it possible to decrease the thermal conduction in mortar by their porous structure. Physical properties of bottom ash including pozzolanic activity and compressive strength test were measured to decide the replacement amount in formulation as well as chemical composition. This study was undertaken on the use of bottom ash as fine aggregate in fire proofing mortar. Various dosage of bottom ash such as 25%, 50%, 75%, 100% were evaluated by several measurement. We found out there were serious correlation between specific gravity and thermal conductivity, so other porous materials were also investigated to decrease the thermal conductivity of cement mortar as well as bottom ash. In this study, the researches on the mixing proportion were mainly performed to design specification of spraying fire proofing mortar. Based on the laboratory test results, we’d like to suggest the proper adding amount of bottom ash by evaluation of consistency and strength development and then optimum mixing proportions of spraying fire proofing mortar using bottom ash by various evaluations.
Authors: Woo Teck Kwon, Soo Ryong Kim, Jong II Kim, Yoon Joo Lee, Ramesh R. Bhave, Y. Kim
Abstract: Polyphenylcarbosilane (PPCS) was synthesized from thermal rearrangement of the polymethylphenylsilane around 350 ~ 430°C. Characterization of synthesized PPCS was performed with FT-IR spectroscopy analysis. From FT-IR data, the band at 1035cm-1 is very strong and assigned to CH2 bending vibration in Si-CH2-Si group, indicating the formation of the PPCS. Ceramic thin film was fabricated onto stainless substrate by dip coating using a 20wt% PPCS in toluene. Heat treatment of the samples was performed at various temperatures (600°C and 800°C) under nitrogen atmospheres. The prepared PPCS samples and the coating layers on SUS316 after heat treatment were analyzed using FT-IR and XPS, respectively.
Authors: Woo Teck Kwon, Young Phil Kim, Y. Kim, Soo Ryong Kim, Seong Youl Bae
Abstract: This paper investigates the effect of the pair-minerializer (CaSO4,-CaF2) on the reaction of alite, belite and calcium langbeinite formation with different alkali and sulfate contents. A set of clinker samples was prepared by adding laboratory grade reagents of (NH4)2SO4, CaF2 and K2CO3 to the cement raw mixes. The mineralogical composition of clinker was analyzed by X-ray powder diffraction, and the quantity of minerals was evaluated by using TOPAS software. As the experimental results, the total amount of calcium silicate minerals was rapidly increased with the addition of F and SO3 components simultaneously as pair-mineralizer with K2O more than the value which mineralizer was added separately. Also, in the case of adding K2O only to the raw mixes, the amount of alite is decreased after clinkering. However, if alkali (K2O) and pair-minerializer (CaSO4,-CaF2) were added simultaneously, the quantity of alite and calcium langbeinite mineral increased because of the formation of stable clinker minerals by the reaction of alkali (K2O) and sulfate.
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