• 한국자동차공학회논문집
• /
• 제17권5호
• /
• pp.67-73
• /
• 2009

Recently, Europe decided to start the regulation of diesel engine nanoparticles because of its well known adverse health effects. The diesel nanoparticles can be classified as solid carbon particles and volatile particles. The volatile particles generates during dilution process by condensation of gas phase volatile compounds such as hydrocarbon. The new nanoparticle regulation considers only solid particles because of difficulty of measurement of volatile particles. The aim of this study is to suggest a proper dilution method that prevent the volatile particle generation. As a result, it is found that the $1^{st}$ dilution air temperature should be above $120^{\circ}C$ in order to prevent volatile particle generation effectively. It is also found that the volatile particles can be removed effectively in the evaporation tube by the increase of evaporation tube temperature. But when exhaust gas is hot enough (>$190^{\circ}C$, in this study) and it is diluted in the first diluter with high temperature air (>$120^{\circ}C$), removal phenomenon of volatile particles by increasing of evaporation tube temperature can not be seen. It means that there are no volatile particles in the diluted exhaust gas. Additionally, dilution ratio is not an important factor for volatile particle generation compared with dilution air temperature or evaporation tube temperature.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 추계학술발표대회
• /
• pp.44.2-44.2
• /
• 2009

Polycrystalline materials suchas yttria and alumina have been applied as a plasma resisting material for the plasma processing chamber. However, polycrystal line material may easily generate particles and the particles are sources of contamination during the plasma enhanced process. Amorphous material can be suitable to prevent particle generation due to absence of grain-boundaries. We manufactured nitrogen-containing $SiO_2-Al_2O_3-Y_2O_3$ based glasses with various contents of silicon and fixed nitrogen content. The thermal properties, mechanical properties and plasma etching rate were evaluated and compared for the different composition samples. The plasma etching behavior was estimated using XPS with depth profiling. From the result, the plasma etching rate highly depends on the silicon content and it may results from very low volatile temperature of SiF4 generated during plasma etching. The silicon concentration at the plasma etched surface was very low besides the concentration of yttrium and aluminum was relatively high than that of silicon due to high volatile temperature of fluorine compounds which consisted with aluminum and yttrium. Therefore, we conclude that the samples having low silicon content should be considered to obtain low plasma etching rate for the plasma resisting material.

• 한국수소및신에너지학회논문집
• /
• 제22권3호
• /
• pp.386-401
• /
• 2011

Mathematical models for various steps in coal gasification reactions were developed and applied to investigate the effects of operation parameters on dynamic behavior of gasification process. Chemical reactions considered in these models were pyrolysis, volatile combustion, water shift reaction, steam-methane reformation, and char gasification. Kinetics of heterogeneous reactions between char and gaseous agents was based on Random pore model. Momentum balance and Stokes' law were used to estimate the residence time of solid particles (char) in an up-flow reactor. The effects of operation parameters on syngas composition, reaction temperature, carbon conversion were verified. Parameters considered here for this purpose were $O_2$-to-coal mass ratio, pressure of reactor, composition of coal, diameter of char particle. On the basis of these parametric studies some quantitative parameter-response relationships were established from both dynamic and steady-state point of view. Without depending on steady state approximation, the present model can describe both transient and long-time limit behavior of the gasification system and accordingly serve as a proto-type dynamic simulator of coal gasification process. Incorporation of heat transfer through heterogenous boundaries, slag formation and steam generation is under progress and additional refinement of mathematical models to reflect the actual design of commercial gasifiers will be made in the near futureK.

• 한국환경과학회지
• /
• 제19권3호
• /
• pp.379-387
• /
• 2010

Sediments of Little Scioto (LS) River in Ohio was contaminated by poor disposal of creosote from Baker Wood Creosoting Facility. Among the primary compounds of creosote, Polycyclic Aromatic Hydrocarbons (PAHs) are the most common ingredient PAHs are known for toxic, carcinogenic and mutagenic compounds. There are many difficulties to remove the PAHs in nature environment because their characteristics are having a less water-solubility, volatile and low mobility properties as increasing the molecular weight. The generation of hydroxyl radicals (${\cdot}OH$) and hydrogen peroxide ($H_2O_2$) forms as well as high temperature (5000 K) and pressure (1000 atm) by a physico-chemical effects of ultrasound during a cavitation collapse can promote the degradation and desorption of PAHs in sediment And it can also produces shock wave and microjets which are able to change the size and surface of particle in solid-liquid system as one of physical effects. Therefore, we explored to understand the role of particle size, the effect of elimination for PAHs concentration by ultrasound and optimize the conditions for ultrasonic treatment. The condition of various size of particles (> $150{\mu}m$, < $150{\mu}m$) and solid-liquid ratio (12.5g/L, 25g/L) for the treatment was considered and ultrasonic power (430 W/L) with liquid - hexane extraction and microwave extraction method were applied after ultrasound treatment.

• 산업기술연구
• /
• 제17권
• /
• pp.37-42
• /
• 1997

Generation and physico-chemical characteristics of municipal solid wastes are very important for sanitary management. However, that has not been investigated so far especially in chunchon. And so, we tried to examine many things in detail. It was resulted that density was $90{\sim}94kg/m^3$ in school and office zone and $290{\sim}298kg/m^3$ in apartment and market place. The compositional weight fraction was food, 40~54%, paper, 14~18%, vinyl and prastic, 14~20% in house zone and market place and paper, 42~70% in school and office zone. Moisture was estimated to be 54~57% in independent house zone, apartment and market place and 11~23% in school and office zone. And three composition was water content, 44.1%, incineration particle, 11.2%, volatile parts, 44.7% in respectively. That is because of seasonal effects and regional chracteristics. In the results of chemical composition and caloric value analysis, carbon(C) was 80% in vinyl and plastic and oxygen(O) was 54.4% in paper.

• 대한기계학회논문집
• /
• 제11권1호
• /
• pp.118-123
• /
• 1987

본 연구에서는 새로 고안된 연료주입기(air injector)바로 뒤에 입사압축파를 반사시키기 위한 벽을 설치하므로써 고체입자의 입사압축파에 대한 노출을 최대한 줄 였고 또한 새로운 연료주입기에 의해 매우 잘 분포된 입자분포를 얻을 수 있었다. 반사압축파에 의해 생성된 고온 고압의 산소중에서의 고체입자의 점화지연시간을 측정 하므로써 기체유동이 존재하는 입사압축파실험에서의 점화지연시간과 비교하여 기체유 동이 고체 미립자의 점화에 미치는 영향을 알아볼 수 있었고 반사압축파에 의한 점화 상태 조건하에서도 표면 점화모델이 성립하는지를 고찰해 보았다.