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        검색결과 29

        3.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전 세계적으로 환경오염 문제로 국제해사기구인 IMO(International Maritime Organization)에서는 이산화탄소 배출량과 관련된 지수인 EEDI(Energy Efficiency Design Index)를 만들어 새로 건조되는 선박들에 대한 규제를 적용하고 있다. 본 연구에서는 158k 원유운반선의 선형과 프로펠러 후류를 분석하여 새로운 형태의 에너지 저감 장치인 ring stator를 제안하였다. 최근의 선박들은 반류가 적은 즉 선미부 유속이 빠른 경향으로 발전되고 있어 덕트가 포함된 ESD(Energy Saving Device)는 저속비대선이라도 컨테이너선처럼 적용하기가 어렵다. 본 연구에서 제안한 ring stator는 이러한 점을 고려하여 새로이 개발된 장치로써 자항 성능 향상 뿐 아니라 저항 성능의 최소화를 목표로 설계를 진행하였다. Star-CCM+의 상용 프로그램을 활용하여 CFD 해석을 통해 설계한 ring stator의 성능을 확인하였고 최종 제시한 설계안에 대해 약 3.4 %의 추진 효율 개선 효과가 있음을 확인하였다. 설계된 ring stator에 대한 실험과의 비교 등을 통해 성능 검증 및 보다 정도 높은 최적화에 대한 연구를 추후 수행할 계획이다.
        4,000원
        5.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the current developments in creation of state security, the question of affording energy security is of paramount importance worldwide. Hence, all countries try to adopt myriads of laws and regulations aimed at energy security. Energy security relates to the degree of economic welfare attached to the rise or fall in either the price or availability of energy. The Islamic Republic of Iran, on the one hand is located in a strategic center of producing and exporting energy (oil and gas) known as “ellipse of energy.” On the other hand, it is situated in the transit way of energy to large consuming markets such as South and East of Asia and Europe. Thus, Iran is currently considered as an effective player in providing energy security in the world. In this article, the authors seek to analyze the strategic policies and priorities stipulated in the oil and gas-related regulations of Iran in terms of energy security.
        5,500원
        7.
        2016.10 구독 인증기관 무료, 개인회원 유료
        본 연구는 유류오염에 의한 요각류 Tigriopus japonicus의 먹이섭식능력의 감소가 먹이회피에 의한 것인지 오염된 해수의 독성에 의한 것인지를 알아보기 위해, 유류(WAF 또는 CEWAF)에 오염된 먹이에 대한 T. japonicus의 먹이 섭식력을 조사하였다. WAF가 없는 배양수 조건에서는 모든 실험구에서 섭식량의 차이를 보이지 않았지만 WAF가 배양수에 있는 조건에서는 WAF의 농도가 증가할수록 섭식량이 줄어드는 경향을 보여 WAF 100% 농도에서는 대조구에 비해 유 의하게 감소하였다. T. japonicus가 CEWAF에 오염된 환경에서 먹이의 종류에 따른 먹이선택성 여부를 조사한 결과, 오염된 먹이를 공급했을 때, 배양수에 CEWAF가 존재하는 상태에서, 먹이 로 Tetraselmis suecica를 공급한 실험구가 다른 실험구에 비해 유의적으로 낮은 부착규조류 섭 식률을 보였다. 결과적으로, 유류오염에 의한 T. japonicus의 먹이 섭식력의 감소는 오염된 먹 이회피에 의한 섭식력의 감소가 아니라 해수에 존재하는 유류독성에 의한 것으로 판단된다.
        4,000원
        10.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oil spills have occurred throughout the years of industrialization and represent a global challenge as they affect vast areas of the ocean. The toxicity of crude oil to aquatic organisms has been extensively investigated, but the potential impacts of crude oil on vertebrate development remain largely unknown. Here, we investigated the effects of dispersants used in treating a recent oil spill, as well as that of crude oil, on vertebrates by using the zebrafish (Danio rerio) model species, which has been widely used in empirical studies of both early embryonic development and adult physiology. Chronic exposure to crude oil resulted in marked developmental abnormalities, including pericardial edema, abnormal trunk vessel development, retardation of axonal branching, and abnormal jaw development. Embryonic development was affected more severely by exposure to the oil-dispersant combination than to the oil alone. Thus, the zebrafish in vivo model system suggests that dispersant treatment can have detrimental developmental effects on vertebrates and its potential impact on marine life, as well as humans, should be carefully considered in clean-up efforts at the site of an oil spill.
        4,000원
        11.
        2012.12 구독 인증기관 무료, 개인회원 유료
        To evaluate the acute to chronic effects of crude oil exposure on hematological and blood biochemical toxicities, Sprague-Dawley rats were given oral doses of 0, 50, or 100 mg/kg BW/day of Iranian heavy crude oil for a period of four weeks. In the acute phase of exposure (one day after four weeks of oil treatment), decreases in weight of thymus, serum level of interferon gamma (IFN-γ), superoxide dismutase (SOD), and catalase activities in liver or kidney, and increase in weight of adrenal gland occurred after oral administration of crude oil. In body weight, histopathological examination, hematological and blood biochemical analyses in the acute phase of exposure, no significant differences were observed among the experimental groups. In the subchronic and chronic phase of exposure (two months and six months after four weeks of oil treatment), the changes of biomarkers were normalized, except the indicators of oxidative stress. Our findings showed that the bioassay on the indicators of oxidative stress is a sensitive method for determining exposure to crude oil in rats.
        4,000원
        13.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly(oxypropylene-oxyethylene glycol) block copolymer(PBC) oil dispersant, which has low toxicity, high biodegradability, and an excellent dispersion efficiency to crude oils and weathered W/O emulsion was prepared by blending PBC, poly(oxyethylene) oleate, and sorbitan monooleate. The dispersing efficiency was measured by swirling flask method. The PBC oil dispersant had an excellent dispersing efficiency to weathered oil products formed as stable W/O emulsion, and the low toxicity, such as 4000 ppm to Oryzias Latipes(24 hr, TLM), Brine Shrimp Artemia(24 hr, TLM).
        4,000원
        14.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A heating cargo is solidified by several reasons during carriage. This study is to analyse a cargo accident which 811,202 US barrels of Nile Blend crude oil reamined solid In the tanks after discharge. There are some possibilities that low temperature of Beading cargo below cloud point and wax appearance temperature at loading time, heating interruption during voyage or discharging, and prohibition of crude oil washing during discharging might influence the cargo solidified. But we concluded that the defect of heating system would most affect the heating cargo solidified locally, and which blocked drain hole of bottom transverse and web frame and they obstruct flow of heating cargo in the tanks.
        4,000원
        15.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyoxyethylene monooleate was prepared by addition of ethylene oxide to oleic acid. And also, polyoxyethylene monooleate type oil dispersant was prepared by blending polyoxyethylene monooleate, n-paraffine, sorbitan monooleate, sorbitan monopalmitate, and palm oil. Dispersion efficiency test was carried out by vertical shaking flask and swirling flask methods. Low toxic oil dispersant was prepared with polyoxyethylene monooleate, which has high biodegradability and excellent dispersion efficiency on crude oils and weathered W/O emulsions with high viscosity, and its dispersion efficiency was measured to various crude oils and weathered oils.
        4,000원
        17.
        2020.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This scholarly work is an effort to capture the effects of oil prices on the actual exchange rate between dollar and rupee. This is done with reference to the U.S. dollar as oil prices are marked in USD (U.S. Dollar) in the international market, and India is among the top five importers of oil. Using monthly data from January 2001 to May 2020. The study used the real GDP, money supply, short-term interest rate difference between two countries, and inflation apart from the crude oil prices per barrel as the factors that help define the exchange rate. The analysis, through cointegration and vector error correction method (VECM), suggests long and short-run causality amid prices of oil and the rate of exchange fluctuations. Oil prices are found to be negatively related to the exchange rate in the long term but positively related in the short term. The result of the Wald test also indicates the short-run causation from the short-term interest rate and the prices of crude oil towards the exchange rate. The present study shows that oil prices are evidence of the existence of short-term and long-term driving associations with short-term interest rates and exchange rates.
        18.
        2020.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this paper, we propose the new time-varying coefficient GARCH-in-Mean model. The benefit of our model is to allow the risk-return parameter in the mean equation to vary over time. At the end of 2019 to the beginning of 2020, the world witnessed two shocking events: COVID-19 pandemic and 2020 oil price war. So, we decide to use the daily data from December 2, 2019 to May 29, 2020, which cover these two major events. The purpose of this study is to find the dynamic movement between risk and return in four major oil markets: Brent, West Texas Intermediate, Dubai, and Singapore Exchange, during COVID-19 pandemic and 2020 oil price war. For the European oil market, our model found a significant and positive risk-return relationship in Brent during March 26-April 21, 2020. For the North America oil market, our model found a significant positive risk return relationship in West Texas Intermediate (WTI) during March 12-May 8, 2020. For the Middle East oil market, we found a significant and positive risk-return relationship in Dubai during March 12-April 14, 2020. Lastly, for the South East Asia oil market, we found a significant positive risk return relationship in Singapore Exchange (SGX) from March 9-May 29, 2020.
        19.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        To produce palm kernel shell (PKS) biocrude oil, a bubbling fluidized bed pyrolyzer was used with different sample sizes and reaction temperatures. The PKS sample sizes used were 0.1 ~ 0.4 mm, 0.4 ~ 1.0 mm, and 1.0 ~ 2.0 mm and the reaction temperature were 465oC, 490oC, 530oC, 560oC, and 590oC. The yield of PKS biocrude oil increased with decreasing the sample size. The maximum yield of PKS biocrude oil was 47.31% at 560oC with a PKS sample size of 0.1 ~ 0.4 mm. In addition, the maximum energy yield of PKS biocrude oil was 45.05% at 560oC and size 0.1 ~ 0.4 mm. Among the characteristics of PKS biocrude oil, the high heating values are from 15.98 MJ/Kg to 20.29 MJ/Kg, the moisture content is from 20.14wt.% to 31.57wt.%, and the viscosity ranges from 0.0117 N s/m2 to 0.0408 N s/m2. In addition, proximate analyses and elemental analysis of PKS biocrude oil were conducted.
        20.
        2017.05 서비스 종료(열람 제한)
        물은 22.1 MPa의 압력하에 100℃ - 374℃의 온도범위에서 액체상태로 존재하며, 이를 아임계수라 한다. 아임계수 조건에서 물은 분자간 수소결합이 약해지면서 유전상수, 점성, 표면장력이 감소되어 유기용매와 유사한 특성을 지니게 된다. 원유오염토양은 전남 여수지역 공단 내에 있는 유류로 오염된 토양을 이용하였으며, 오염기간은 약 1년이며 저분자성 휘발유류성분 및 고분자성 유류로 오염되어 있었다. 초기 오염된 TPH농도는 16,895 mg/kg였다. 원유오염토양은 고분자성 물질이 다량 함유되어 있어 기존정화방법으로는 처리하기 어려운 점이 있다. 이를 해결하기 위하여 상기 아임계수 특성을 이용하여 원유로 오염된 토양으로부터 오염물질을 추출하는 연구를 수행하였다. 이와 함께 친유성 용매인 등유를 이용하여 토양으로부터 원유 일부를 탈착(전처리)시킨 후, 아임계수로 토양 내에 잔류되어 있는 유류성분을 제거하는 실험도 수행하였다. 이를 통해 아임계수 추출만을 적용하였을 경우와 등유 전처리가 추가된 경우의 제거율과 정화공정상 효율을 비교하였다. 아임계수 추출 시 275℃에서 2시간 추출을 5회 반복 진행하였을 때, 토양 내의 잔류 유류 농도가 498 mg/kg(제거율 97%)로 나타났다. 등유 전처리(토양 : 등유=1 : 0.5 wt%)후 아임계수 적용시 250℃에서 1시간동안 추출 시, 토양 내 잔류 유류 농도는 223 mg/kg로 나타났다. 적용된 두가지 공정 모두 토양1지역 우려기준(500mg/kg)이하로 정화되었으나, 상대적으로 등유전처리가 포함된 공정이 아임계수 기술만을 적용하여 추출을 진행한 것보다 상대적으로 높은 제거율을 보였다. 또한 등유 전처리가 추가된 아임계 공정이 추출시간, 공정수, 투입에너지(가열)에 있어 경제적으로 판단되며, 따라서 원유 오염토양의 아임계수 정화공정에서는 등유전처리 도입이 효과적인 것으로 판단된다.
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