• 환경위생공학
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• 제21권1호
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• pp.66-75
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• 2006

When we looked at the seasonal food dregs of the eastern side of gangwondo, gangneung city's summer and winter food dregs showed 25.9 and 25.8% respectively due to the presence of beach areas and ski resorts. Sokcho city showed 28.12% in summer and yangyang gun's summer food dregs showed 40.2%. Yangyang gun's august food dregs showed 2.7 times larger than annual average amount. Outlook density showed regional characteristics. Data showed that food dregs' amount rate has been reduced gradually from 2005 because of the prohibition of direct filling up. As a result of compositions analysis, the eastern side of gangwondo's water fraction of living dregs were lower than that of chuncheon city where is located at the gangwondo's inland area. chuncheon city's data showed residential areas 53.5%, community areas 56.8% and commercial areas 55.6%. These discrepancies caused by the characteristics of dregs discharge type and climate. The caloric value of dregs has been increased incrementally after the ban of food dregs' direct filling up. Therefore, heating value of the dregs exceeds the existing furnace design spec and it can cause high caloric value problems, so we need additional research to solve these problems.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.853-856
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• 2008

Windows have an great effect on annual building load because windows are the weakest parts of building envelope thermally. To reduce the consumption of building energy, the thermal performance of window has to be improved in first place. Therefore this research aims to make a quantitative analysis of the heating and cooling load according to the window thermal performance using the heat load simulation program. As a result of the simulation, annual heat load is down 38% according to the decrease of U-value of window, 1.00 W/$m^2K$. and annual heat load is up 10% according to the decrease of shading coefficient, 0.20. The annual load of the window with Low-E glass is 15% lower than the window with pair glass.

• 토지주택연구
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• 제3권2호
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• pp.169-175
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• 2012

최근, 지열 냉난방 시스템의 초기 공사비를 절감하기 위해 연구되고 있는 에너지 파일의 열교환량을 산정하기 위해 2종류(부속연결형, 슬링키형)의 현장타설말뚝형(PRD, 시공심도 4.5m, 직경 1,200mm) 에너지 파일을 시험시공하고 수치 시뮬레이션에 의해 효율을 상호 비교하였다. 상호 비교결과에 의하면 지중 교환량은 운전시작과 함께 채열에 의한 지중온도의 저하에 의해 점점 감소하였고 부속연결형의 평균 열원수의 온도차는 난방운전에서 $0.37^{\circ}C$, 냉방운전에서 $0.34^{\circ}C$로 나타났다. 또, 부속연결형의 난방운전시 열교환량 231.4W/m보다 냉방운전의 방열량은 252.2W/m로서 9% 높았고 슬링키형은 난방 기간 평균 열교환량이 168.0W/m로 부속연결형에 비해 약 27% 낮은 열교환량을 얻었다.

• 한국식품위생안전성학회지
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• 제24권4호
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• pp.368-372
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• 2009

본 연구에서는 우리나라에서 2-3번째로 자주 발생하는 식중독 원인균인 S. aureus를 대상으로 불충분한 열처리와 NaCl처리에 따른 각각의 생존균수 변화와 불충분한 열처리 후 다양한 NaCl농도(0%, 2%, 4%, 6%)하에서 sublethal injured cell의 회복 정도를 조사하였다. 그 결과, 불충분한 열처리 정도가 증가함에 따라 생존균수가 유의적인 감소를 하였으나, NaCl 처리시 NaCl 농도가 6%까지 증가함에 따라서 생존균수의 변화가 거의 없었다. 그리고 $55^{\circ}C$나 $60^{\circ}C$에서 30분간 열처리하는 기간 동안에 sublethal injured cell들이 발생하였으며, 그들의 회복 정도는 높은 염농도에 노출될수록 회복 정도가 감소하였다. 또한 이와 같은 현상은 같은 온도에서 열처리 시간이 증가할수록 더욱 명확히 나타났다. 그리고 동일한 온도에서 sublethal heating 후 노출된 NaCl 농도가 증가함에 따라서 D-value가 감소하는 경향을 나타내었다. 이와 같은 결과는 불충분한 열처리 과정에 의하여 생성된 sublethal injured cell들이 열처리 후 회복되는 과정에서 배지의 NaCl 농도가 증가함에 따라서 회복 정도가 감소하였음을 의미한다.

• Food Science and Biotechnology
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• 제14권6호
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• pp.732-737
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• 2005

The combinational effect of gamma irradiation and moist heating on the trypsin inhibitor activity (TIA) in soaked and dried soybeans was evaluated by measuring the inhibition using N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) as substrate. Gamma irradiation significantly decreased the TIA level in soybean at doses above 5 kGy, and the $ID_{50}$ (the gamma irradiation dose required to reach 50% inhibition) value for TIA was 13.53 kGy. Soaking prior to gamma irradiation significantly lowered the $ID_{50}$ to 8.44 kGy, and the soaking process enhanced the efficiency to inactivate TIA by as much as 48%. When soaking prior to gamma irradiation was followed by subsequent mild heating ($60^{\circ}C$) process, the $IT_{50}$ (heating time required to reach the 50% inhibition of TIA) value at even 1 kGy (5.28 min) was greatly reduced by over 50% compared to the level for the no-soaking process. In addition, the activation energy of soaking prior to gamma irradiation at 1 kGy was 2.45 kcal/mole, which was also about 50% lower than the 5.10 kcal/mole of dried soybean gamma-irradiated. Based on these results, soaking prior to gamma irradiation is an effective method for TIA inhibition. Furthermore, a combination of two or more processing methods such as soaking, heating and gamma irradiation is much more effective than any single processing method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.103.1-103.1
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• 2010

Recently domestic wood pellet boilers are installed in rural and forestry houses. The fuel price per lower heating value of wood pellet is about 20 % lower than that of heating oil on July 2010. In spite of lower price of wood pellet, a few user of wood pellet boiler complain expensive fuel cost. One of this reason is inaccurate or improper air-fuel ratio setting of wood pellet boiler. O2 concentration of flue gas of domestic wood pellet boiler is about 9.7 % and there are few domestic wood pellet boiler which can control air-fuel ratio automatically. We tested a domestic wood pellet boiler in changing boiler thermal output and air-fuel ratio. The nominal boiler thermal output is 25 kW (21 500 kcal/h). We measured thermal efficiency and flue gas concentrations such as CO and NOx at each boiler thermal load with various air-fuel ratio. The results show that if air flow rate is the same as full load and part load, thermal efficiency of part load of 40 % drops about 7.7 %p compared to boiler full load case.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.219-222
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• 1999

Concrete is to be important quality in placement point and exact test method needed about early judgement method concrete on placement point. But early judgement method of concrete proposed various kind of method because the problems of accuracy and the time required of test exists, it is used within the limits. This study is to propose of early strength judgement by using microwave for accurate estimating early strength of concrete and to develop test machine. Through out this study we find that belows. 1) Strength development of concrete specimen according to the time heated by microwave showed the height strength development in 9 minutes regardless of slump and w/c. 2) As cooling time is long, strength of concrete specimen according to the time heated by microwave showed high strength development and this tendency is like regardless of heating time, w/c and slump. 3) As w/c is high, accelerating strength development according to w/c showed lower strength development and this tendency is like regardless of slump, heating time and cooling time. 4) As slump is big, compressive strength of specimen in standard curing showed lower value and as w/c is big, strength development showed lower

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.105-106
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• 2019

In this research, considering the practical conditions at field, thermal cracking method was suggested based on the comparative analysis between predicted value and actual value obtained from the actual structure member with optimum mix design. The optimum mix design was deduced from the various mix designs with various proportions of cementitious binder for upper and lower placement lifts of mat-foundation mass concrete. Therefore, it can be stated that applying low heat mix design and different heating technique between upper and lower placement lifts for mass concrete are efficient to control the thermal cracking. As future issues, based on the interpretation result value, we will select the optimal combination that is applied specifically to the actual site, and deeply analyze the correlation between the measured value and the analysis value through the combination and the test of the actual structure.

• 설비공학논문집
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• 제29권9호
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• pp.482-495
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• 2017

Degree-days are practically used as a tool to estimate energy consumption for heating and cooling. Degree-days are calculated by summing differences of balance point temperature and outside temperature for the analyzed period. Determining balance point temperature is a key point in calculating accurate degree-days. However, ASHRAE standards are used for balance point temperature in Korea because balance point temperature considering climate conditions and building thermal performance is not proposed in Korea. This study proposes the process to generate balance point temperature for heating degree-days considering Korean climate and building conditions. Also, a new balance point temperature for three regions in Korea will be suggested in this study. Balance point temperature of Seoul is approximately $15.0^{\circ}C$, lower than the current standard of $18.3^{\circ}C$. Balance point temperature of Seoul considering climate conditions and building performance can be different from the ASHRAE suggested value ($18.3^{\circ}C$). Results revealed the current standard for balance point temperature should be changed considering climate and building conditions in Korea.

• 한국농공학회지
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• 제35권3호
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• pp.81-90
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• 1993

Groundwater and animal wastes are typical example which are underutilized resources than their value in agriculture. This paper was to investigate the actual patterns of utilization of water curtain for greenhouses and methane gas utilization from swine wastes in a view point of promoting more efficient use of alternative energy. The results from measurements can be summarized as follows : 1.It was estimated that the maximum heating load per l0a was around 23,2804/hr and the heating load at January showed 3.93X 1064 respectively for strawberry greenhouses with insulation by the water curtain. 2.The average heating cost of the greenhouse with water curtain system amounted to about 75,000 Won per l0a. This result suggested that the greater cultivated area provides less heating cost. 3.The operating volume was about 73 percent of the optimum size of the digester. The net available methane gas rates of the produced gas remained close to 62 percent, But the conventional and small size of the digester was maintained at a lower level of around 20 to 29 percent. 4.It appeared that major problems of biogas production system were required to maintain the temperature of the fermentation above ambient temperature and the optimum volume of digester.