• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.519-525
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• 2009

The catalytic steam reforming of woody biomass tar and soot to convert a synthetic gas containing hydrogen was investigated by using a bench-scale biomass gasification system. One commercial nickel-based catalyst, Katalco 46-6Q, and two different kinds of natural minerals, dolomite and olivine, were tested as a reforming catalyst at various reforming temperatures. The reaction characteristics of woody biomass tar were also investigated by TGA at a variety of heating rates. With all three catalysts conversion efficiency of tar and soot increased at increasing temperature. The reforming of tar and soot in the synthetic gas induce the increase of combustible gases such as $H_2$, CO and $CH_4$ in the product gas. The nickel-based catalyst showed a higher tar and soot conversion efficiency than mineral catalysts under the same temperature conditions.

• International Journal of Costume and Fashion
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• 제10권1호
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• pp.29-45
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• 2010

In order to provide more systematic approach to analyze fabric trends and to develop fabrics accordingly, ecology fabric trend from 1986 to 2005 was analyzed related with fabric trend themes and fabric attributes. The result shows that in the 1980s, natural theme appeared, followed by primitive theme and imitated natural theme until the mid 1990s. From the late 1990s to the early 2000s, new natural theme appeared, followed by eco-friendly theme, and then recycling theme. In the natural theme, 'clean' was the most important fabric attribute and 'textured' and 'worn' were important fabric attributes in the primitive theme. In the imitated natural theme, 'wet' fabric attribute was preferred. In the new natural theme, 'lightweight' were preferred. The results of this study empirically demonstrated that abstract and ambiguous trend terms can be interpreted with a physical, substantial, and feasible attributes that fabric practitioners can easily understand.

• 농촌계획
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• 제3권2호
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• pp.81-89
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• 1997

Still today, many streams are channelized and embanked in Korea. On the other hand, some urban streams are being restored to their natural shapes by landscape planners. It would be better to improve rural streams in a way that would not require restoration in later days. Then, one important question is what kind of embankments the residents prefer for what reasons. Five simulated photos showing from very natural to artificial embankments were used in surveying 90 residents of three villages. Major findings are ; 1. Residents regard safety(from flooding) is the most critical factor to be considered in selection of stream bank materials. 2. They think ideal materials are natural stones or concrete blocks as they look tidy. Concrete retaining walls or vegetated natural slopes are not regarded good. 3. The most preferred material is concrete retaining wall, and the least preferred is vegetated natural slope. They prefer concrete retaining wall which they do not think an ideal material, because it will make a safe bank. 4. Natural stone bank is most preferred for its apperance, and vegetated natural slpoe is most disliked as it may collapse and as it does not look clean.

• 한국가스학회지
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• 제2권2호
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• pp.34-39
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• 1998

국내에 액화천연가스가 도입된 이래 환경에 대한 문제를 인식함에 따라 천연가스의 수요는 계속적으로 증가하고 있다. 청정연료인 천연가스는 용접에 의해 고장력강 배관을 사용하여 각 도시로 공급되고 있다. 천연가스 공급용 배관은 공급압력에 따라 중압관과 고압관으로 구분된다. 배관은 주로 작업의 용이성으로 피복아크용접에 의해 용접되며, 현장 작업여건에 따라 다른 용접공정이 적용되기도 한다. 본 연구는 고압관으로 사용되는 API 5L X42 배관에 대한 용착금속부의 미세조직 변화와 기계적 특성을 관찰하였다.

• 기술사
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• 제34권3호
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• pp.28-32
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• 2001

Using the CNG(compressed natural gas) and LPG(liquified petroleum gas) as the automotive fuel will be expanded because of their clean effect to the environmental air qualify. But these programs of gas using expansion would have a difficulty due to public consideration of gas utilities as a big hazard. The Ministry of Environment has an ambitious plan to substitute more than 25,000 buses with CNG and ensure more than 200 CNG refueling stations as well by the year of 2007. However, it is very difficult to establish new CNG and LPG refueling stations because of expanded safety distance than ever before by several major explosion accidents.

• 한국자동차공학회논문집
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• 제3권3호
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• pp.9-18
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• 1995

The substitution of conventional fuel oil by alternative fuels is of immense interest due to liquid oil shortage and requirements of emission control standard. Among the alternative fuels, natural gas may be the most rational fuel, because of its widespread resource and clean est burning. Meanwhile, engine simulation is of great importance in engine development. Hence a zero-dimensional combustion model was developed for dual-fuel system. Natural gas was injected directly into the cylinder and small amount of distillate was used to provide the ignition kernel for natural gas burning. The intake air and exhaust gas flow was modeled by filling and emptying method. Although the single zone approach has an inherent limitation, the model showed promise as a predictive tool for engine performance. Its simulation was also made to see how the engine performance was influenced by the fuel injection timings and amount of each fuel.

• 청정기술
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• 제2권1호
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• pp.69-79
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• 1996

석탄가스화기에서 방출되는 황을 제어하는 것은 가스정화시스템에서 연료가스 중의 황화수소를 제거하는 것이다. 이에 본 연구에서는 천연산 망간광석의 황화수소 제거능에 영향을 미치는 탈황제의 입자크기, 황화반응 온도 및 탈황제 특성에 대해서 고찰하였다. 실험결과 황화수소 제거능은 반응온도 $700^{\circ}C$에서 효과적이었으며 입자크기가 작을수록 탈황효율은 증가하였으나 그 차이는 크지 않았다. 온도가 증가할수록 탈황제의 응집으로 인해 입자 내 물질전달저항이 증가하여 반응성이 저하되며 SEM 사진으로 탈황제의 응집을 확인할 수 있었다. 실험으로부터 구한 평형비 ($P_{H_2O}/P_{H_2S}$)는 ${\log}(P_{H_2O}/P_{H_2S})=5653/T-3.7909$였다. 천연산 망간광석의 황화수소 제거능이 기존에 개발되어 있는 탈황제들과 비슷하기 때문에 탈황제로 사용할 수 있음을 알았다.

• 한국축산식품학회지
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• 제44권4호
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• pp.849-860
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• 2024

The use of natural ingredients in meat processing has recently gained considerable interest, as consumers are increasingly attracted to clean-label meat products. However, limited research has been conducted on the use of natural substitutes for synthetic phosphates in the production of clean-label meat products. Therefore, this study aimed to explore the potential of oyster shell powder as a substitute for synthetic phosphates in pork patties cured with Chinese cabbage or radish powders. Four different groups of patties were prepared using a combination of 0.3% or 0.6% oyster shell powder and 0.4% Chinese cabbage or radish powder, respectively. These were compared with a positive control group that contained added nitrite, phosphate, and ascorbate and a negative control group without these synthetic ingredients. The results showed that patties treated with oyster shell powder had lower (p<0.05) cooking loss, thickness and diameter shrinkage, and lipid oxidation than the negative control but had lower (p<0.05) residual nitrite content and curing efficiency than the positive control. However, the use of 0.6% oyster shell powder adversely affected the curing process, resulting in a decreased curing efficiency. The impact of the vegetable powder types tested in this study on the quality attributes of the cured pork patties was negligible. Consequently, this study suggests that 0.3% oyster shell powder could serve as a suitable replacement for synthetic phosphate in pork patties cured with Chinese cabbage or radish powders. Further research on the microbiological safety and sensory evaluation of clean-label patties during storage is required for practical applications.

• 청정기술
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• 제7권3호
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• pp.187-194
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• 2001

석탄가스화 복합발전(IGCC)의 탈황공정에 사용되는 비아연계 탈황제 중 경제성이 우수한 천연망간광석을 이용하여 황화수소 제거반응에 대한 특성을 연구하였다. $H_2S$와 천연망간광석 탈황제 사이의 반응에 대한 초기 반응 속도를 $400{\sim}800^{\circ}C$의 온도범위에서 열중량 분석기로 실험하였다. 그 결과로 황화수소 제거반응 시 초기 반응은 1차 반응이었고, 반응속도상수는 Arrhenius 식에 잘 적용할 수 있었다. 또한 황화반응이 확산에 의해 제어되는 조건에서 농도 구배가 선형을 나타내었으며, 이를 통하여 유효 확산 계수를 온도에 따른 Arrhenius식으로 나타내었다. 이 결과를 통하여 황화 반응 시 확산에 대한 활성화 에너지와 반응 빈도 인자를 구하였다.

• 청정기술
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• 제10권4호
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• pp.203-213
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• 2004

천연가스의 열분해법은 천연가스 (CH4)를 고온에서 분해 시켜 수소와 탄소로 전환시키는 기술이다. 천연가스 열분해법의 가장 큰 장점은 이산화탄소의 발생 없이 수소와 탄소를 만드는 것이다. 본 연구에서는 이와같이 천연가스 고온 열분해법을 이용하여 메탄으로부터 수소와 탄소의 생성을 연구하였다. 실험을 통하여 메탄의 고온 열분해시 pyrocarbon이 반응관 내벽에 생성되며 그 위에 탄소가 퇴적되는 plugging 현상이 발생한다는 것을 알 수 있었다. 이 문제를 해결하기 위하여 본 연구에서는 이중관 반응기법, 반응 중간에 주기적으로 $O_2$나 $CO_2$로 퇴적된 탄소를 산화시키는 방법 등을 시도하였으며, 그 결과 어느 정도의 탄소 퇴적 현상을 해결할 수 있었다. 또한 SEM (Scanning Electron Microscope) image를 사용하여 탄소 입자의 크기를 측정하였으며 그 크기는 약 200 nm정도였다.