• 청정기술
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• 제24권4호
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• pp.365-370
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• 2018

Oil shale은 kerogen을 함유한 퇴적암으로 대표적인 비재래 에너지자원으로 알려져 있다. 열분해 공정을 통하여 oil shale이 분해되면 oil, gas 및 coke를 생성하게 된다. 본 연구에서는 oil shale의 청정 전환기술을 개발하기 위하여 oil shale의 TGA 및 연속 열분해 연구를 수행하였다. Oil shale의 열분해 전환율에 대한 반응 온도 및 체류시간의 영향을 살펴보고 oil의 생성율을 살펴보았다. Oil shale의 열분해 전환율은 온도와 체류시간에 따라 증가하였으며 $450{\sim}500^{\circ}C$, 체류시간 30 min의 조건에서 최대 oil 생산 수율을 나타내었다.

• 기술사
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• 제38권5호
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• pp.1-4
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• 2005

• 건축사
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• 통권573호
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• pp.50-63
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• 2017

• 보건교육건강증진학회지
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• 제28권2호
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• pp.27-40
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• 2011

Objectives: This study was conducted to identify health-promoting behaviors and related factors by type of residence between two groups of college students: those who live in dormitories and those who commute from home. Methods: We used the data from 2,287 students (870 male, 1417 female) from 14 colleges in Daegu and Kyungpook areas and compared health-promoting practice scores, general characteristics, health environment, and parental support. Multiple regression analysis was performed with health-promoting practice scores as a dependent variable. Results: Dormitory residents presented significantly lower health-promoting practice scores than commuters in both gender. Multiple regression analysis showed that the factors associated with health-promoting behaviors were health environment (p<0.05) and parental influence/support (p<0.01) for male dormitory residents. For female dormitory residents interest in health(p<0.05), stress(p<0.05), and parental influence/support(p<0.01) were associated. Conclusions: Systematic development of health education programs would be needed for the practice of health promotion behavior of college dormitory students with the help of environmental and institutional support. We suggest a program for stress management, smoking, health behavior, and alcohol and a parental program to increase contact with their children for a positive parental influence and support.

• 한국물환경학회지
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• 제24권1호
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• pp.44-53
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• 2008

To recognize the spatial and temporal variability of water temperature and dissolved oxygen in the Youngsan reservoir formed after dike construction, water temperature and dissolved oxygen data have been observed and analyzed from April, 2002 until March, 2003. As the results, certain stratifications were not distinctly observed in the Youngsan reservoir during summer, which was estimated due to the drainage characteristic from the Youngsan water gates. The yearly variation of water temperature in the Youngsan reservoir is shown seasonally ups and downs by the heat exchange between the atmosphere and the reservoir. On the other hand, dissolved oxygen and water temperature in the Youngsan reservoir have been shown inversed proportional correlation. As the calculation results of residence time and water exchange rate, it is considered that the feature of oxygen distribution is determined by the drainage characteristics caused the shortest residence time during summer, which also disturbed the formation of stratification in the Youngsan reservoir.

• 한국해양환경ㆍ에너지학회지
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• 제12권4호
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• pp.248-254
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• 2009

영산강 하구해역에서 계절별로 물질순환과 영양염 플럭스 특성을 파악하기 위해 단순 박스모델을 이용하여 담수수지, 염분수지, 영양염 물질수지를 산정하였다. 외해, 시스템영역으로 유입되는 계절적 평균담수의 양은 $36.481{\times}10^6{\sim}663.634{\times}10^6m^3/month$로 나타났다. 염분수지에 의해 계산된 담수존재량은 $2.515{\times}10^6{\sim}5.812{\times}10^6m^3$이었고 평균 체류시간은 0.26~2.03일로 계산되었다. 평균체류시간은 계절별로 큰 차이를 보였는데 강우가 집중된 하계 풍수기에는 0.26일의 짧은 체류시간을 보인 반면 추계 갈수기에는 2.03일의 평균체류시간을 나타내었다. 해수교환량은 $1,248{\times}10^6{\sim}9,489{\times}10^6m^3/month$으로 하계 풍수기에 해수교환량이 가장 크게 나타났다. 영양염의 부하량은 DIP과 DIN가 각각 2.9~61.22 ton/month, 76.63~1,149.91 ton/month로 계산되었다. 영양염의 체류시간은 DIP의 경우 0.45~1.10일의 범위를, DIN의 경우 0.28~1.92일의 범위를 보였고, 담수체류시간과 비교하면 DIP과 DIN는 하계를 제외한 전 계절에서 담수 체류시간 보다 짧은 체류시간을 보여 영양염이 빠르게 순환되는 것을 알 수 있었다. 특히 DIP는 동계에 외해에서 상대적으로 높은 농도를 보이고 같은 시기에 해수교환에 의한 플럭스가 시스템 영역내로 유입되는 결과를 보여 외부 유입원 존재를 추정하게 하였다.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.426-432
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• 2017

Hydrothermal carbonization (HTC) is an effective and environment friendly technique; it possesses extensive potential towards producing high-energy density solid fuels. it is a carbonization method of thermochemical process at a relatively low temperature ($180-250^{\circ}C$). It is reacted by water containing raw material. However, the production and quality of solid fuels from HTC depends upon several parameters; temperature, residence time, and pressure. This study investigates the influence of operating parameters on solid fuel production during HTC. Especially, when food waste was reacted for 2 hours, 4 hours, and 8 hours at $200^{\circ}C$ and 2.0-2.5 MPa, Data including heating value, proximate analysis and water content was consequently collected and analyzed. It was found that reaction temperature, residence time are the primary factors that influence the HTC process.

• Asian Journal of Atmospheric Environment
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• 제11권3호
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• pp.184-193
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• 2017

People spend the majority of their time in indoor environments. Maintaining adequate indoor temperature and humidity is necessary to support health and improve quality of life. However, people with low incomes can be vulnerable because they may not be able to use effective cooling and heating systems in their homes. In this study, the indoor temperature and humidity in low-income residences over a year in Seoul, Korea was characterized. Indoor temperature and humidity were measured in three types of homes (12 rooftop residences, 16 basement residences, and 18 public rental apartments) occupied by low-income residents. Both differed significantly among the three types of residence, particularly during the summer and winter seasons. A regression model between indoor and outdoor temperature detected a heating threshold at $3.9^{\circ}C$ for rooftop residences, $9.9^{\circ}C$ for basement residences, and $17.1^{\circ}C$ for public rental apartments. During tropical nights and cold-wave advisory days, rooftop residences showed the most extreme indoor temperatures. This study demonstrates that people living in rooftop residences could be at risk from extreme hot and cold conditions.

• 한국지역사회생활과학회지
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• 제25권3호
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• pp.321-338
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• 2014

This study was examined the level of satisfaction in rural settlement and analyzed its differences according to various demographic variables and characteristics of urban-rural migration. The analysis was conducted by considering returning farmers residing in rural areas. A statistical analysis was conducted using t-test, one-way ANOVA, and Duncan's multiple-range test with a total of 210 responses. First, satisfaction with the convenience of living facilities varied significantly according to the occupation before urban-rural migration, responses of family members and friends to urban-rural migration, and the initial capital for urban-rural migration. Second, satisfaction with the natural environment varied significantly according to age and reasons for urban-rural migration. Third, satisfaction with the transportation environment varied significantly according to gender, the period of residence after urban-rural migration, and the employment type of the returning farmer. Fourth, satisfaction with neighborliness varied significantly according to parents' occupation, agricultural experience before urban-rural migration, experience in agriculture-related social life before urban-rural migration, reasons for urban-rural migration, the type of urban-rural migration, and the employment type of the returning farmer. Fifth, satisfaction with the agricultural environment varied significantly according to responses of family members and friends to urban-rural migration, the period of residence after urban-rural migration, and reasons for urban-rural migration. Sixth, satisfaction with the housing environment varied significantly according to the residential area, the agricultural experience before urban-rural migration, and the period of residence after urban-rural migration.

• Ecology and Resilient Infrastructure
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• 제6권4호
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• pp.208-216
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• 2019

본 연구는 하천 내의 자연형 수질정화기법으로 박층류 하도의 설계방법과 효율에 대해서 연구하였다. 박층류 하도의 설계인자를 고려하여 설계를 수행하고 오산천 고수부지에 시험구간을 조성하여 모니터링을 수행하였다. 수위, 유속, 유량, T-N, T-P, NO₃-N 등에 대한 모니터링 결과를 이용하여 제거효율을 평가하고 설계식을 제시하였다. T-N, T-P, NO₃-N 등의 제거효율은 10 - 20%로 나타났으며 체류시간과 일정한 관계를 나타내고 있다. 또한 조류 형성과 유속 간의 관계를 통해 최소 유속 조건을 제시하였다. 본 연구에서 제시된 체류시간과 제거효율의 관계식은 차집수로 설계와 운영에 유용할 것으로 기대된다.