• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1815-1820
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• 2008

The aim of this study was to extract chicken leg bone, which is a by-product of industrial poultry processing, using different heating temperatures (80, 90 and $100^{\circ}C$) and durations (5, 10 and 15 min). The pH value, soluble protein content, peptide content and antioxidative properties, including superoxide anion scavenging ability, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, reducing capacity and inhibitory activity of linoleic acid peroxidation, were measured. The results showed no significant differences (p>0.05) in pH value among all treatments. Decreased soluble protein content and peptide content were observed in chicken leg bone extract obtained under higher heating temperatures (90 or $100^{\circ}C$) and longer heating durations (10 or 15 min). In antioxidative properties, the extracts which were heated at 90 or $100^{\circ}C$ for 15 min exhibited significantly higher superoxide anion scavenging ability, DPPH free radical scavenging ability, reducing capacity and inhibitory activity of linoleic acid peroxidation (p<0.05).

• 한국식품조리과학회지
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• 제6권2호
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• pp.67-76
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• 1990

To observe the propability as the frying oil and oxidative stability of red pepper seed oil, some physico-chemical tests of the oil were examined during 21 days storage period at 5$^{\circ}C$, 15$^{\circ}C$ and 30$^{\circ}C$, and AOM value determined and after heating the oil at 180${\pm}$5$^{\circ}C$ for 40 hours with or without antioxidants. The analysis storage stability of red pepper seed oil showed that the quality of storage group at 5$^{\circ}C$ was almost as good as fresh oil, and the storage group at 30$^{\circ}C$ showed certain degree of rancidity. Change of physico-chemical characteristic during storage were so small so that storage stability of red pepper seed oil was found to be good. AOM stability of red pepper seed oil was 7 hours which is lower than other vegetable oil, but the degree of stability grew greatly after adding phenolic antioxidants, such on TBHQ or PG. As for the chemical change after heating continuously for 40 hours, acid value, peroxide value and refractive index increased, but iodine value decreased as the heating processed. The fatty acid composition also showed the remarkable reduction of linoleic acid. The addition of antioxidants resulted in the delay of oxidation, the degree of which was greater in TBHQ than in PG.

• 한국안전학회지
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• 제11권2호
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• pp.96-101
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• 1996

The effects of coal type and mixing fraction of coal on attrition and elutriation were studied in a 15. 5cm diameter fluidized bed coal combustor. The domestic low-grade anthracite coal with heating value 2010kcal/kg and the imported bituminous coal from Australia with heating value of 6520kcal/kg were used as coal sample. It was found from the experimental that the elutriation rate inclosed with an increseing anthracite mixing fraction. The size of elutriated particle had a very wide distribution was found in this experiment. The mean size of elutriated particle increased with decreaseing anthracite mixing fraction.

• 태양에너지
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• 제2권1호
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• pp.49-58
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• 1982

Aim of this study was to obtain the heating performance and the economic evaluation on solar heating system for greenhouse which area of floor was $90m^2$. For heating performance effective solar energy for the greenhouse was compared with overall heating loads including coefficient of heat transfer and conduction. And the economic evaluation solar heating system was evaluated by comparison its initial investiment costing with oil saving cost. Initial investiment costing included collector cost, storage cost, piping cost, control system cost and miscellaneous costs which included pumps, motors etc. The contents of this study included the survey of climate conditions for solar heating, long-term collector performance and optimum collector area of solar heating system in existing greenhouse. The results are follows: 1. Average horizontal radiation during winter was $2,434Kcal/m^2$ day which was the highest value in this country, so the climate conditions of Suwon was suitable for solar heating. 2. Resulting calculation of the optimum collector area was $30m^2$ and the solar energy accounted for 30% of the overall heating load. 3. The capacity of storage tank required 60 liter per unit area ($m^2$) of solar collector.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.57-63
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• 2012

Effects of coolant pre-cooling and fuel pre-heating on the performance of a combined cycle using a F-class gas turbine were investigated. Coolant pre-cooling results in an increase of power output but a decrease in efficiency. Performance variation due to the fuel pre-heating depends on the location of the heat source for the pre-heating in the bottoming cycle (heat recovery steam generator). It was demonstrated that a careful selection of the heat source location would enhance efficiency with a minimal power penalty. The effect of combining the coolant pre-cooling and fuel pre-heating was also investigated. It was found that a favorable combination would yield power augmentation, while efficiency remains close to the reference value.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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• pp.79-82
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• 2002

Induction heating is widely used in today's industry, in operations such as metal hardening, preheating for forging operations, melting or cooking. In this paper, it was presented the magneto-thermal analysis of an induction heating jar(IH-JAR) with the material value of the stainless and the aluminum for efficient design. The magnetic field intensity inside the axisymmetric shaped cooker was analyzed using three-dimensional axisymmetric finite element method(FEM) and the effectual heat source was obtained by ohmic losses from eddy currents induced in the jar. The heat was calculated using the heat source and heating equation. Also, it was represented the temperature characteristics of the IH-JAR according to time and relative permeability in stainless parts and in aluminum parts.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2256-2261
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• 2008

The electric snow melting and deicing system by electric heating cable which is adopted in this study is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow or ice accumulated on it. The electric heating cables are buried under paved road at a certain depth and a certain pitch and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, and installation place. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitches for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating cables (200 mm, 300 mm), heating value ($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• Current Research on Agriculture and Life Sciences
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• 제28권
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• pp.53-62
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• 2010

원적외선 조사가 포도씨 기능성분의 변화에 미치는 영향을 알아보고자 가열출력(0, 900, 1800 W) 및 가열시간(0, 20, 40 min)을 달리하여 원적외선 조사 후 마이크로파를 이용하여 포도씨 추출물을 제조하고 기능성분으로서 가용성 고형분, 기계적 색도, 카테킨, 총 페놀, 총 플라보노이드 함량 및 전자공여능과 아질산염 소거능을 각각 측정하였다. 가용성 고형분 함량 및 백색도 및 적색도는 유의적인 차이가 없는 것으로 나타났다. Cathechin류는 가열시간에 따라 catechin, procyanidin $B_2$, epicatechin 함량의 변화가 있음을 확인하였으며, 총 catechin 함량은 총 카테킨 함량은 900 W 및 20분 처리 시 가장 높게 나타났다. 총 페놀성화합물 및 플라보노이드 함량 또한 가열출력 900W 및 가열시간 20분 일 때 가장 높게 나타났다. 그에 따라 전자공여능도 가열출력 900 W 및 가열시간 20분 일 때 가장 높은 것으로 나타났다. 이상의 결과는 원적외선 처리에 의해 총 페놀성 화합물 함량, 총 플라보노이드 함량이 증가됨을 볼 수 있었으며, 특히 cathechin류의 변화가 있음을 확인할 수 있었다. 또한 이로 인해 항산화능도 증가됨을 알 수 있었다. 또한 포도씨의 원적외선 가열처리 최적조건을 설정하고자 가열출력 및 가열시간을 달리하여 중심합성실험계획으로 반응표면분석한 결과 가열출력 621.82~818.18 W, 가열시간 16.3~19.83 min의 범위가 최적 가열조건범위로 설정되었다.

• 설비공학논문집
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• 제30권4호
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• 유기물자원화
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• 제18권3호
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• pp.60-67
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• 2010

우리나라의 대형 생활폐기물소각시설의 건설시기를 보면 상당수가 1980년대 후반인 것을 알 수 있다. 대부분의 시설들은 이 시기에 설계되었으며 그 후에 건설된 소각로 역시 변경이나 조정 없이 시설해온 것으로 조사되고 있다. 그러나 소각로에 반입되는 폐기물의 성상은 정부의 폐기물수거 정책에 의해 급격히 변화하고 있다. 이는 생활폐기물의 발열량변화를 조사해 봄으로도 쉽게 알 수 있다. 그 결과 많은 소각시설에서 과열에 의해 내화물과 화격자가 손상되고 있다. 한편 보일러 전열면에 클링커가 생성되어 열전달에 방해를 줌으로 이용열량이 줄어들 뿐만 아니라 연소실의 온도가 상승되는 등 원하지 않는 현상이 연속되고 있다. 이를 개선하기 위해 폐기물저장고에 물을 뿌리거나, 분리수거해 온 음식물류 폐기물을 다시금 혼합하여 혼소하거나 연소실에 물을 분사하는 방법을 동원하고 있다. 이러한 방법은 근본적인 해결책이 되지 않으며, 설계부터 다시 하여 새로 시설하는 것 또한 비용적인 측면에서 효과적이지 못하다. 따라서 본 연구를 통해 위와 같은 문제를 원천적으로 해결 하기위한 방법을 도출해 보았다.