• Elastomers and Composites
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• 제35권2호
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• pp.106-114
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• 2000

상온에서의 충격 흡수특성과 compression set 특성을 향상시키기 위하여 ethylene vinyl acetate copolymer (EVA)와 styrene vinyl isoprene styrene triblock copolymer (SVIS)를 블렌드하여 발포체를 제조하였다. 발포제 및 EVA/SVIS 블렌드비가 발포배율 및 기계적 물성에 미치는 영향을 조사하였다. SVIS 함량이 증가함에 따라 블렌드의 점도는 증가하였고 가교 속도는 감소하였으며, 발포배율은 감소하여 비중은 증가하였다. 발포제 함량 증가, 즉 발포배율 증가에 따른 반발탄성은 변화가 없는 반면에, SVIS 함량 증가에 따라 발포체의 상온에서의 tan ${\delta}$ 값은 증가하였으며 따라서 반발 탄성은 감소함을 알 수 있었다. EVA/SVIS 블렌드 발포체에서 SVIS 함량 증가에 따라 가교밀도와 비중이 증가하므로 compression set 값도 낮은 값을 나타내었다.

• 한국태양에너지학회 논문집
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• 제26권3호
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• pp.9-16
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• 2006

A solar collector surface coated with a low emission material is still imported from other developed countries expensively. Thus it is very significant to develop a new coating method with a cheap alternative coating material instead of the imported high-cost collector surface. A thermal spray method was adopted to coat a cheap Titania on a copper plate. Generally, a new coating on the copper plate was conducted successfully by selecting a proper ratio of carbon and acetylene. By measuring an absorption rate of solar and heat emission rate, all the plate types gained a high absorption rate of 98% approximately, more or less, but all of the types still have a high emission. Finally it was clear that more research is needed to advance the coated-plate to subdue the high emission from the hot plate surface and the higher the Titania's proportion is, the lower the emission is on the surface.

• 한국대기환경학회지
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• 제20권2호
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• pp.153-159
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• 2004

This study was focused on evaluating physical properties and SO$_{x}$ removal capability of porous lime filters prepared by a foaming and a gelcasting method. Porosities of lime filters ranged from 55% to 85%, and their mean pore sizes were about 95 ${\mu}{\textrm}{m}$. It was observed that porous lime filters had the continuous pore structure that most pores were inter-connected by many windows. Before SO$_{x}$ removal reaction a surface of porous lime filters was made up of calcium oxide, but after reaction calcium sulfate became a main component. The SO$_{x}$ removal efficiency and the conversion ratio of calcium oxide to calcium sulfate increased according to reaction temperature and porosity. At 100$0^{\circ}C$, SO$_{x}$ removal efficiency of filters was always over 98% regardless of the porosity. In case of the filter with the porosity of 85%, the conversion ratios of calcium oxide increased according to the reaction temperature, and they were in the range 30% to 60%. to 60%.

• 한국농공학회지
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• 제36권4호
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• pp.48-55
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• 1994

This study was performed to evaluate the engineering properties of the lightweight concrete using surlightweight aggregate foaming agent and high performance agent. The following conclusions were drawn. 1. The unit weight of type A, B and C concrete was 0.912t/m$^3$, 1.592t/m$^3$ and 1.070t/m$^3$, respectively. Specially, the unit weight of type A concrete was decreased 42% than that of the type B concrete. 2. The highest engineering property was measured in the lightweight concrete using high performance agent Also, the ratio of tensile and bending strength to compresive streng-th of the lightweight concrete was higher than that of the normal cement concrete. 3. The dynamic modulus of elasticity of the lightweight concrete was in the range of 2.86 x 10 5~9.86 x 10 5 kg/cm$^2$ which was approximately 300% than that of the normal cement concrete. 4. The ultrasonic pulse velocity of the lightweight concrete was in the range 2047~3394 n/sec, which was smaller than that of the normal cement concrete.

• 공학논문집
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• 제8권1호
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• pp.31-50
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• 2006

수축은 콘크리트에 균열을 발생시키는 경우도 있다. 일반적 조건하에서는 콘크리트의 건조를 피할 수 없으며 건조가 일어나면 수축이 생기므로 대부분의 콘크리트 적용분야에서는 실제로 이와 같이 균열발생을 고려하여야 한다. 균열이 발생한 콘크리트는 균열이 없는 콘크리트에 비하여 강도가 약하고 투과성이 크며 화학적 침식의 영향을 받기 쉽다. 또 재령의 경과에 따라 경량기포콘크리트의 강도발현은 기포제의 종류, 물과 시멘트와의 비, 양생조건 및 기간 등과 같은 인자에 의존하고 있다. 경량기포콘크리트의 강도가 높으면 높을수록 수축에 의하여 균열이 발생할 가능성이 감소한다. 그러므로 온돌구조용으로의 경량기포콘크리트의 강도는 소포율과 시멘트의 건조수축과의 균열저감효과에 크게 의존된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.209-212
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• 2001

Aircraft industry is developed very fast so titanium scrap was generated to manufacture. Titanium scrap was wasted and used to deoxidize cast iron so we are study recycling of it. In this research were studied that metal hydride of reacted in hydrogen chamber of AMS4900, 4901, return scrap titanium alloy and sponge titanium granule. The temperature of hydrogenation was 40$0^{\circ}C$ in the case of pure sponge titanium but return scrap titanium alloy were step reaction temperature at 40$0^{\circ}C$ and 50$0^{\circ}C$, and after the hydride of titanium alloy were crushed by ball mill for 5h. Titanium hydride contains to 4wt.% of hydrogen theoretically as theory. It was determined by heating and cooling curve in reaction chamber. The result of XRD was titanium hydride peak only that it was similar to pure titanium. Titanium hydride Powder particle size was about 45${\mu}{\textrm}{m}$, and recovery ratio was 95w% compared with scrap weight for a aluminum foam agent.

• Design & Manufacturing
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• 제10권3호
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• pp.20-24
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• 2016

Foaming is a step of forming by the ratio of the internal combustion chamber in a state where the in flow of the material is suppressed, if the diameter is small and a high to a crack generated on the molding is not possible. The present study, we studied using as part experiments for forming the circular shape of the forming height of 10 mm without the occurrence of cracks, results preformed primary, the need to set the height of the forming than the height of the product, preformed secondary. It was able to increase the height of the molded product with less than the height of the next step to be carried out compression processing to create a small comer of the desired shape. In addition, it was found that on a great influence on the quality of the final quality on the final molding of the primary preformed, secondary.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1404-1410
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• 2009

Chestnut flours (CFs) were produced from 3 chestnut samples (Aydin, Kutahya, and Bursa) by 2 different methods (boiled and oven-dried: BOD-CF and freeze-dried: FD-CF). Functional properties and effects of CF addition (10, 20, and 30%) on the qualities of regular and low-fat cookie were investigated. The freeze drying significantly increased water solubility of CFs but decreased their water binding capacity. The emulsion capacity and stability of FD-CFs were higher than those of BOD-CFs. At pH 4, 6, 8, and 10 FD-CFs had better gelation properties. Spread ratio (SR) values of BOD-CF supplemented regular or low-fat cookies decreased with increasing CF levels. Hardness values of CF supplemented regular cookies were generally lower compared to control. SR and hardness values of FD-CF supplemented cookies were higher than those of BOD-CF supplemented ones. Surface colors of the cookies were darker with FD-CF addition as compared to BODCF addition. In low-fat cookies, the sample supplemented with 10% Kutahya FD-CF had the highest taste-flavor value. FDCF supplementation generally resulted in higher appearance and taste-flavor scores than BOD-CF supplementation in cookies.

• 공업화학
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• 제16권4호
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• pp.519-526
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• 2005

소다석회 조성의 폐 유리를 발포유리의 원료로 활용하기 위해 폐유리의 가수분해를 시도하였다. 소다석회유리 조성으로 만들어진 판유리 및 병 유리 등은 공히 가압 하에서 증기상의 물 또는 액체상의 물에 의해 효율적으로 가수분해가 진행되었다. 최적의 가수분해의 조건은 공히 $250^{\circ}C$, 2 h이었으며 이 조건하에 얻어진 수화유리의 함수율은 발포유리의 원료유리로서 발포화가 가능한 7.85~10.04%였다. 수식제인 Na성분은 액상의 물에 의한 가수 분해에 효율적이며 유시시료에 대한 중량비로서 0.04첨가 시 가장 높은 함수율을 지닌 수화유리가 얻어졌다.

• 한국세라믹학회지
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• 제55권1호
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• pp.61-66
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• 2018

In this study, fabrication method of inorganic insulation were studied to reduce $CO_2$ from buildings. Main materials for inorganic insulation were used cement, blast furnace slag and aluminum powder as foaming agent. Mixing ratio of cement and slag was controlled and physical properties of inorganic insulation were analyzed. When inorganic insulation was fabricated using cement and slag, expanded slurries were not sunken and hardened normally. Pore size was 0.5 - 2 mm; mean pore size was about 1mm in inorganic insulation. Compressive strength of inorganic insulation increased with curing time and increased slightly with cement fineness. However, specific gravity decreased slightly with curing time; this phenomenon was caused by evaporation of adsorptive water. When inorganic insulation was dried at $60^{\circ}C$, compressive strength was higher than that of undried insulation. The highest compressive strength was found with a mixture of cement (50%) and slag (30%) in inorganic insulation. Compressive strength was 0.32 MPa, thermal conductivity was 0.043 W/mK and specific gravity was $0.12g/cm^3$.