• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.144-145
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• 2021

Calcium silicate hydrate(C-S-H) is the principal binding phase that controls the strength and thermal stability of concrete. However, the effects of high temperature on the lattice structure and interatomic structure of C-S-H remains poorly understood due to its nanocrystallinity. This study aims to elucidate the change in interatomic distance of synthetic C-S-H with different Ca/Si molar ratios after exposure to high temperature via high energy X-ray scattering experiment which is a powerful analytical tool for amorphous materials.

• Clean Technology
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• v.14 no.2
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• pp.117-122
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• 2008

Theoretical analysis was conducted on the combustion and the NOx formation characteristics of the coal-derived synthetic gases with medium-BTU heating value. The synthetic gas was assumed to contain the major species of CO, $H_2,\;CO_2$, and $N_2$ and the minor species of $CH_4$ and $NH_3$. Through thermochemical analysis on the combustion of the synthetic gas, the flame temperature, major and minor species of exhaust gas, and thermal and fuel NOx emissions were computed. In addition, the effects of the $CH_4$ and the $NH_3$ components in syngas fuel on combustion and NOx emission were investigated. Based on the computed results on the synthetic gases, basic direction and guidelines were provided fur the low NOx design of gas turbine combustor.

• Journal of Welding and Joining
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• v.27 no.1
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• pp.79-84
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• 2009

Ferritic stainless steel, which has been used as material for decoration parts in automobile, is recently used as material for the exhaust system due to its good performance at high temperature. To improve the fuel efficiency and purify automotive exhaust gas, it is needed to increase the temperature of exhaust gas. However, it is frequently reported that the rising of the temperature of exhaust gas increases thermal stress at exhaust manifold, which results in thermal fatigue failure in welded joints. Therefore, in this study, effects of chemical composition of steel and welding parameters on thermal fatigue properties of synthetic heat affected zone in ferritic stainless steel have been investigated. It has been found that thermal fatigue life in heat affected zone is affected by bead shape of welded joint and amount of soluble Nb in steel. Especially, Nb-Ti added steel has higher thermal fatigue life in comparison to Nb added steel, which is attributed to difference of precipitation behavior in both steels.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.223-226
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• 2009

In this study, we investigated the recovery of copper and synthetic fuel from the waste wire by low temperature pyrolysis which can overcome problems of the recent incineration methods. Through thermal decomposition process of waste wire, we achieved the big advantage of getting usable resources as the forms of copper and fuel with a very high value. The TG/DTA and small-scale reaction experiments were carried out to determine an optimum temperature for waste wire pyrolysis. And the pyrolysis was done at 350, 450, and $550^{\circ}C$, respectively, and heating rate of the TG/DTA was $5^{\circ}C/min$ untill $700^{\circ}C$. The result shows that the optimum temperature range for dehydrochlorination of PVC was $280{\sim}350^{\circ}C$, as a lower temperature range than $400{\sim}550^{\circ}C$ of PE and PP. Practically over 95% of copper metal and synthetic fuel, which has the 8027 kcal/kg as a calorific value, were recovered from the waste wire samples.

• Fire Science and Engineering
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• v.27 no.4
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• pp.41-46
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• 2013

The present study has been conducted to investigate the reaction kinetics and pyrolysis parameters for flame propagation analysis of furniture material components. TGA measurement for component materials such as MDF (medium density fiberboad) panel including coating material, synthetic leather and foam cushion are performed under maximum temperature of $600^{\circ}C$ and heating rate of $10^{\circ}C/min$. The results of TGA have shown that the peak temperature of MDF panel was $324^{\circ}C$ and the initial peak temperature of coating material decreased by $270{\sim}280^{\circ}C$. In the case of synthetic leather and foam materials, the reference temperature and reference rate depend on the type of polymer consisting the sample, the initial kinetic characteristics was classified into 2 categories of about $270^{\circ}C$ and $420^{\circ}C$ of reference temperature for the tested synthetic materials. The present study showed the pyrolysis parameters of reference temperature and reference rate proposed by Lyon to evaluate the pre-exponential factor and activation energy. The present study can contribute to improve the reliability of computational fire analysis and enhance the understanding of fire propagation phenomena based on the thermal properties study of material.

• Clean Technology
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• v.12 no.2
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• pp.78-86
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• 2006

Computational analyses are conducted on the combustion characteristics of the coal- and the biomass-derived synthetic gases with low-Btu heating value in gas engine. Using thermochemical analyses on the synthetic gases, combustion pressure, temperature, exhaust gas composition, NO emission and engine power are predicted and the predicted results are compared with small-scale pilot engine test results. In order to investigate the unsteady combustion phenomena in gas engine combustion chamber, CFD analyses are carried out on the coal and the biomass synthetic gases and their computed results are compared to provide the guidelines for the design modification and the tuning of the gas engine burning the synthetic gases as alternative fuels.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.1
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• pp.79-85
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• 1987

The purpose of this study was to help the consumer about the care of nonwoven fabrics by investigation of the properties such as launderability. shrinkage, color fastness and strenth. Materials used were two types, soft and stiff, of commercial nonwoven fabrics. Deter-gents used were neutral detergents, synthetic detergents and dry cleaning solutions(perch-toro-ethylene) The results of this study were summerized as follows; 1. Laundering of nonwoven fabrics in low temperature is more ideal as morphological changes by laundering in high temperature were more prominent than that in low temperature. 2. Ironing of nonwoven fabrics wants more attention on environmental temperature as the rate of shrinkage in high temperature was higher than that in low temperature. Neutral detergents are more desirable as the rate of shrinkage of nonwoven fabrics by laundering with synthetic detergents was more prominent than that with neutral deter-gents. The rate of shringkage of nonwoven fabrics was not affected by dry cleanining. 3. Special care is wanted in order to prevent color transfer from non woven fabrics to polyester or wool during dry cleaning or laundering as the color fastness test show that color changes of nonwoven fabrics were not affected, but that color stain was increased on polyester or wool. 4. The strength was affected by composition of fibers and types of nonwoven fabrics, soft or stiff.

• Textile Coloration and Finishing
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• v.13 no.5
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• pp.41-41
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• 2001

In this study, synthetic fiber fabrics such as polyester, nylon 6, acrylic and acetate were dyed with indigoid vat dye. The effects of the composition of alkaline reduction, dyeing time and dyeing temperature on color strength and color fastness of the fabrics were investigated. Also the color fastnesses to wash and light of the dyed fabrics were studied. In dyeing of polyester, nylon, acrylic and acetate fiber fabrics with indigo vat dyes, it appears that these fabrics have high values of K/S up to Ig/L of sodium hydroxide and 6g/L of reducing agent. Indigo vat dyeing for synthetic fiber fabrics was verb fast, and lead to dyeing equilibrium within twenty minutes. The K/S values of dyed fabrics did not changed in dye concentration more than 10% o.w.f.. Synthetic fiber fabrics dyed with indigoid dyes had bad light fastness.

• Textile Coloration and Finishing
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• v.13 no.5
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• pp.329-335
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• 2001

In this study, synthetic fiber fabrics such as polyester, nylon 6, acrylic and acetate were dyed with indigoid vat dye. The effects of the composition of alkaline reduction, dyeing time and dyeing temperature on color strength and color fastness of the fabrics were investigated. Also the color fastnesses to wash and light of the dyed fabrics were studied. In dyeing of polyester, nylon, acrylic and acetate fiber fabrics with indigo vat dyes, it appears that these fabrics have high values of K/S up to Ig/L of sodium hydroxide and 6g/L of reducing agent. Indigo vat dyeing for synthetic fiber fabrics was verb fast, and lead to dyeing equilibrium within twenty minutes. The K/S values of dyed fabrics did not changed in dye concentration more than 10% o.w.f.. Synthetic fiber fabrics dyed with indigoid dyes had bad light fastness.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.213-223
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• 2009

Conventional additives were added to a newly synthesized base oil to create synthetic lubricants. Commercial polyol ester prepared in this laboratory were obtained as esterification of 1,1,1-trimethylol propane and respectively. This newly synthesized base oil had a variable chemical structure that could achieved the following properties; oxidation or thermal stability, low temperature fluidity, and higher flash points. When compared with commercial mineral lubricants, the synthetic lubricants show superior thermal and oxidation stability, and anti-wear properties.