• 제목/요약/키워드: Total Energy Release Rate

검색결과 45건 처리시간 0.017초

강원도 일부도시의 경관내 탄소흡수 및 배출과 도시녹지의 역할 (Carbon Uptake and Emissions in Urban Landscape, and the Role of Urban Greenspace for several Cities in Kangwon Province)

  • 조현길
    • 한국조경학회지
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    • 제27권1호
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    • pp.39-53
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    • 1999
  • This study quantified carbon uptake and emissions in urban landscape, and the role of urban greenspace in atmospheric carbon reduction for several cities of Chuncheon and Kangleung in Kangwon province. Mean carbon storage by trees and shrubs was 26.0 t (mertric tons)/ha in Chuncheon and 46.7 t/ha in Kangleung for natural lands, and ranged from 4.7 to 6.3 t/ha for urban lands (all land use types except natural and agricultural lands) in both cities. Mean annual carbon uptake by trees and shrubs ranged from 1.60 to 1.71 t/ha/yr for natural lands, and from 0.56 to 0.71 t/ha/yr for urban lands. There was no significant difference (95% confidence level) between the two cities in the carbon storage and annual carbon uptake per ha, except the carbon storage for natural lands. Organic carbon storage in soils (to a depth of 60 cm) of Chuncheon average 24.8 t/ha for urban lands and 31.6 t/ha for natural lands, 1.3 times greater than for urban lands. Annual carbon accumulation in soils was 1.3 t/hr/yr for natural lands of the study cities. Annual per capita carbon emissions from fossil fuel consumption were 1.3 t/yr in Chunceon and 1.8 t/yr in Kangleung. The principal carbon release in urban landscapes was from transport and industry. Total carbon storage by urban greenspace (trees, shrubs, and soils) equaled 66% of total carbon emissions in Chuncheon and 101% in Kangleung. Carbon uptake by urban greenspace annually offset total carbon emissions by approximately 4% in the study cities. Thus, urban greenspace played a partial important role in reducing atmospheric $CO_2$ concentrations. To increase $CO_2$ uptake and storage by urban greenspace, suggested are conservation of natural lands, minimization of hard surfaces and more plantings, selection of tree species with high growth rate, and proper management for longer healthy tree growth.

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압축비 변화에 따른 초희박 직접분사식 LPG엔진의 연소특성 연구 (Study of Combustion Characteristics with Compression Ratio Change in Ultra-Lean LPG Direct Injection Engine)

  • 조시현;윤준규;박철웅;오승묵
    • 대한기계학회논문집B
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    • 제38권10호
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    • pp.837-844
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    • 2014
  • 최근 자동차 제조사는 강화되는 배출가스 규제를 만족시키고 엔진 효율을 향상시키기 위해 다양한 기술을 연구하고 있다. 그 중 직접분사식 초희박 연소기술은 정밀한 연소제어를 통해 연소효율을 극대화 하고 연비를 향상시킬 수 있는 차세대 기술로 평가받고 있다. 기존 가스엔진에 초희박 직접분사기술을 적용하기 위해 기존의 MPI 엔진의 헤드를 재설계하였다. 기존 압축비10:1에서 12:1로 증가시킴으로써 이에 따른 압력선도, 열방출률, 연료소비율 등의 연소특성과 배출가스특성을 파악하였다. 압축비를 증가시킴에 따라 불안정한 연소상태로 인하여 연료소비율의 개선이 어려웠으나 탄화수소(THC)와 질소산화물(NOx)의 배출은 감소되었다.

화염 전파모델을 이용한 소파화재 설계화원구성의 적용성 연구 (Feasibility Study on the Fire Scenario Design of a Couch Burning through a Fire Spread Model)

  • 김성찬
    • 한국화재소방학회논문지
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    • 제30권6호
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    • pp.37-42
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    • 2016
  • 본 연구는 화재전파해석 모델을 이용하여 화재 위험성 평가에 적용되는 설계화재 구성의 적용가능성을 파악하고자 한다. 화재전파해석을 위해 열중량분석과 시편연소실험이 수행되었으며 실험에서 얻어진 물성을 FDS 열해리 모델에 적용하여 격자크기에 따른 화재해석을 수행하였다. 해석 결과 전체적인 화재성장특성은 실화재 실험결과와 큰 차이를 보였으나 초기 피크 발열량과 전체 방출 열에너지는 약 30% 이내에서 유사한 예측결과를 보였다. 본 연구의 해석모델은 화재성장율이나 최대발열량 도달시간 등과 같은 화재성장특성을 예측하는데 한계를 보였다. 그러나 지속적인 모델의 개선 및 재료 물성의 상세연구를 통해 설계화재시나리오 구성에 있어서 화재모델의 적용성이 있음을 보여준다.

밭 토양(土壤)의 점토(粘土) 광물(鑛物)과 가리(加里) (Potassium and Clay Minerals in Upland Soils)

  • 김태순
    • 한국토양비료학회지
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    • 제10권3호
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    • pp.135-151
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    • 1977
  • 우리나라 토양(土壞)의 점토(粘土) 광물(鑛物) 특성(特性), 점토(粘土) 광물(鑛物)과 가리(加里), 점토(粘土) 광물(鑛物)의 가리(加里) 방출(放出) 특성(特性), 점토(粘土) 광물(鑛物)과 토양비옥도(土壤肥沃度), 점토(粘土) 광물(鑛物)을 이용(利用)한 토양(土壤) 개량(改良)에 관(關)해서 지금까지 행(行)하여진 연구(硏究) 결과(結果)를 종합(綜合)한 것을 요약(要約)하면 다음과 같다. 1) 밭 토양(土壞)은 대부분(大部分)이 적황색토(赤黃色土)이며 이들 토양(土壞)의 주(主) 점토(粘土) 광물(鑛物)은 kaolin 광물(鑛物)(halloysite)과 운모(雲母) 류(類)의 풍화(風化) 중간(中間) 생성물(生成物)인 illite, vermiculite이다. 2) 토양(土壞) 모재별(母材別)로 보면 kaolin 광물(鑛物)은 화강암(花崗岩)과 화암(花岩) 편마암질(片麻岩質)과 토양(土壞)에 많고 운모(雲母)는 현무암질(玄武岩質) 토양(土壞)에 많다. 제(第) 3 기층(紀層)에 기인(基因)된 토양(土壞)은 ontmorillonite를, 제주도(濟州道) 화산회토(火山灰土)는 allophane을 주(主) 점토(粘土) 광물(鑛物)로 하고 있다. 3) 지방(地力)은 토양(土壞)의 점토(粘土) 광물(鑛物)에 크게 의존(依存)하고 있다. 적황색(赤黃色) 토양(土壞)의 생산력은 이 토양(土壞)의 점토(粘土) 광물(鑛物)의 주체(主體)가 kaolin 광물(鑛物)이므로 저위(低位) 생산성을 나타내고 있는데 비(比)해서 montmorillonite 토양(土壞)은 kaolin광물(鑛物) 토양(土壞)보다 생산력이 높다. 4) 토양(土壞) 고상(固相)에 있는 가리(加里)(운모류(雲母類)와 고정가리(固定加里))의 평형액(平衡液)($IN-NH_4OAc$)에의 방출(放出) 속도(遠度)는 1차(次) 반응식(反應式)에 따르고 있으며 가리(加里) 방출(放出) 정수(定數)는 점토(粘土) 중(中)의 운모(雲母) 함량(含量)과는 정(正)의 상관(相關)이 있고 점토(粘土) 중(中)의 $14.5{\AA}$ 광물(鑛物) 함량(含量)과는 부(負)의 상관(相關) 관계(關係)가 있다. 또한 가리(加里) 방출(放出) 정수(定數)는 치화성(置換性) 가리(加里)(Kex)와 전(全) 가리(加里)(Kt)와의 비(比) 즉 Kex/Kt와도 고도(高度)의 상관(相關)이 있다. 5) Kex/kt는 토양중(土壞中)의 운모(雲母) 함량(含量), 점토(粘土) 중(中)의 운모(雲母) 함량(含量) $14.5{\AA}$ 광물(鑛物) 함량(含量)과 고도(高度)의 상관(相關) 관계(關係)가 있다.

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한국의 지역개발과 댐건설 (Regional Development And Dam Construction in Korea)

  • 안경모
    • 물과 미래
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    • 제9권1호
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    • pp.38-42
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    • 1976
  • Because of differences in thoughts and ideology, our country, Korea has been deprived of national unity for some thirty years of time and tide. To achieve peaceful unification, the cultivation of national strength is of paramount importance. This national strength is also essential if Korea is to take rightful place in the international societies and to have the confidence of these societies. However, national strength can never be achieved in a short time. The fundamental elements in economic development that are directly conducive to the cultivation of national strength can be said to lie in -a stable political system, -exertion of powerful leadership, -cultivation of a spirit of diligence, self-help and cooperation, -modernization of human brain power, and -establishment of a scientific and well planned economic policy and strong enforcement of this policy. Our country, Korea, has attained brilliant economic development in the past 15 years under the strong leadership of president Park Chung Hee. However, there are still many problems to be solved. A few of them are: -housing and home problems, -increasing demand for employment, -increasing demand for staple food and -the need to improve international balance of payment. Solution of the above mentioned problems requires step by step scientific development of each sector and region of our contry. As a spearhead project in regional development, the Saemaul Campaign or new village movement can be cited. The campaign is now spreading throughout the country like a grass fire. However, such campaigns need considerable encouragement and support and the means for the desired development must be provided if the regional and sectoral development program is to sucdceed. The construction of large multipurpose dams in major river basin plays significant role in all aspects of national, regional and sectoral development. It ensures that the water resource, for which there is no substitute, is retained and utilized for irrigation of agricultural areas, production of power for industry, provision of water for domestic and industrial uses and control of river water. Water is the very essence of life and we must conserve and utilize what we have for the betterment of our peoples and their heir. The regional and social impact of construction of a large dam is enormous. It is intended to, and does, dras tically improve the "without-project" socio-economic conditions. A good example of this is the Soyanggang multipurpose dam. This project will significantly contribute to our national strength by utilizing the stored water for the benefit of human life and relief of flood and drought damages. Annual average precipitation in Korea is 1160mm, a comparatively abundant amount. The catchment areas of the Han River, Keum River, and Youngsan River are $62,755\textrm{km}^2$, accounting for 64% of the national total. Approximately 62% of the national population inhabits in this area, and 67% of the national gross product comes from the area. The annual population growth rate of the country is currently estimated at 1.7%, and every year the population growth in urban area increases at a rising rate. The population of Seoul, Pusan, and Taegu, the three major cities in Korea, is equal to one third of our national total. According to the census conducted on October 1, 1975, the population in the urban areas has increased by 384,000, whereas that in rural areas has decreased by 59,000,000 in the past five years. The composition of population between urban and rural areas varied from 41%~59% in 1959 to 48%~52% in 1975. To mitigate this treand towards concentration of population in urban areas, employment opportunities must be provided in regional and rural areas. However, heavy and chemical industries, which mitigate production and employment problems at the same time, must have abundant water and energy. Also increase in staple food production cannot be attained without water. At this point in time, when water demand is rapidly growing, it is essential for the country to provide as much a reservoir capacity as possible to capture the monsoon rainfall, which concentarated in the rainy seaon from June to Septesmber, and conserve the water for year round use. The floods, which at one time we called "the devil" have now become a source of immense benefit to Korea. Let me explain the topographic condition in Korea. In northern and eastern areas we have high mountains and rugged country. Our rivers originate in these mountains and flow in a general southerly or westerly direction throught ancient plains. These plains were formed by progressive deposition of sediments from the mountains and provide our country with large areas of fertile land, emminently suited to settlement and irrigated agricultural development. It is, therefore, quite natural that these areas should become the polar point for our regional development program. Hower, we are fortunate in that we have an additional area or areas, which can be used for agricultural production and settlement of our peoples, particularly those peoples who may be displaced by the formation of our reservoirs. I am speaking of the tidelands along the western and southern coasts. The other day the Ministry of Agriculture and Fishery informed the public of a tideland reclamation of which 400,000 hectares will be used for growing rice as part of our national food self-sufficiency programme. Now, again, we arrive at the need for water, as without it we cannot realize this ambitious programme. And again we need those dams to provide it. As I mentioned before, dams not only provide us with essential water for agriculture, domestic and industrial use, but provide us with electrical energy, as it is generally extremely economical to use the water being release for the former purposes to drive turbines and generators. At the present time we have 13 hydro-electric power plants with an installed capacity of 711,000 kilowatts equal to 16% of our national total. There are about 110 potential dams ites in the country, which could yield about 2,300,000 kilowatts of hydro-electric power. There are about 54 sites suitable for pumped storage which could produce a further 38,600,000 kilowatts of power. All available if we carefully develop our water resources. To summarize, water resource development is essential to the regional development program and the welfare of our people, it must proceed hand-in-hand with other aspects of regional development such as land impovement, high way extension, development of our forests, erosion control, and develop ment of heavy and chemical industries. Through the successful implementation of such an integrated regional development program, we can look forward to a period of national strength, and due recognition of our country by the worlds societies.

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