• International Journal of Ocean System Engineering
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• 제1권4호
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• pp.230-235
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• 2011

Reinforced polyurethane foam (RPUF) is one of the important materials of Mark III type insulation systems used in liquefied natural gas (LNG) cargo containment systems. However, RPUF is the most difficult material to use with regard to its safety assessment, because there is little public and reliable data on its mechanical properties, and even some public data show relatively large differences. In this study, to investigate the structural response of the system under compressive loads such as sloshing action, time-dependent characteristics of RPUF were examined. A series of compressive load tests of the insulation system including RPUF under various temperature conditions was carried out using specimens with rectangular section. As a result, the relationship between deformation of RPUF and time is linear and dependent on the loading rate, so the concept of strain rate could be applied to the analysis of the insulation system. Also, we found that the spring constant tends to converge to a value as the loading rate increases and that the convergence level is dependent on temperature.

• 대한기계학회논문집A
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• 제26권1호
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• pp.203-210
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• 2002

The transmission pipeline industry spends many millions of dollars annually performing inline inspections, excavating sites of possible corrosion, and repairing or replacing damaged sections of pipe. New criteria fur evaluation of the integrity of corroded pipe have been developed in recent years to help in controlling these costs. These new criteria vary widely in their estimates of integrity and the most appropriate criterion fur a given pipeline is net always clear. This paper presents an overview, comparison and evaluation of acceptability criteria for corrosion deflects in pipelines. By full scale burst tests, this paper has assessed the relative accuracy of each of theses criteria in predicting burst pressure. Many of the criteria appear to be excessively conservative and indicate that deflects must be repaired when none is needed, based upon burst test data.

• KIEAE Journal
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• 제13권6호
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• pp.99-104
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• 2013

Many activities associated with the construction and habitation of buildings are connected with issues affecting the environment such as global warming, climate change, and consumption of valuable natural resources such as fossil fuels. To minimize negative impacts on the environment, the building industry worldwide has implemented green building practices in many countries. One of the main green strategies is to reduce greenhouse gas emissions caused by residential structures because they are most substantially connected with global warming and climate change. To determine the actual quantity of green house gas emissions caused by the construction and use of a building, it is important to analyze total greenhouse gas emissions over the life cycle of buildings including construction, operation & maintenance(O&M) and demolition stages. Many studies suggest methods to calculate greenhouse gas emissions at the construction stage, but the literature addressing greenhouse gas emissions at the O & M stage is limited. A year-long study was conducted utilizing the deterioration method to calculate greenhouse gas emissions at the O & M stage of building life for condominium types of buildings in South Korea. Through this research, it is possible to analyze greenhouse gas emissions of buildings at the O & M stage, the longest span of the life cycle, and eventually help to calculate total greenhouse gas emissions over the life cycle of the building.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.545-553
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• 2006

Generally, the temperature drop under $0^{\circ}C$ on vaporizer surface creates frozen dews. This problem seems to increase as the time progress and humidity rises. In addition, the frozen dews create frost deposition. Consequently, heat transfer on vaporizer decreases because frost deposition causes adiabatic condition. Therefore, it is very important to solve this problem. This paper aims to study of the optimum design of used vaporizer at local LNG station. In this paper, experimental results were compared with numerical results. Geometries of numerical and experimental vaporizers were identical. Studied parameters of vaporizer are angle between two fins $(\Phi)$ and fin thickness $(TH_F)$. Numerical analysis results were presented through the correlations between the ice layer thickness $(TH_{ICE})$ on the vaporizer surface to the temperature distribution of inside vaporizer $(T_{IN})$, fin thickness $(TH_F)$, and angle between two fins $(\Phi)$. Numerical result shows good agreement with experimental outcome. Finally, the correlations for optimum design of vaporizer are proposed on this paper.

• Corrosion Science and Technology
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• 제16권2호
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• pp.85-89
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• 2017

One of the most challenging issues in the oil and gas industry is corrosion assessment and management in subsea structures or equipment. At present, almost all steel pipelines are sensitive to corrosion in harsh working environments, particularly in salty water and sulphur ingress media. Nowadays, the most commonly practiced solution for a damaged steel pipe is to entirely remove the pipe, to remove only a localized damaged section and then replace it with a new one, or to cover it with a steel patch through welding, respectively. Numerous literatures have shown that fiber-reinforced polymer-based composites can be effectively used for steel pipe repairs. Considerable research has also been carried out on the repair of corroded and gouged pipes incorporated with hybrid natural fiber-reinforced composite wraps. Currently, further research in the field should focus on enhanced use of the lesser and highly explored hybrid-biocomposite material for the development in corrosion prevention. A hybrid-biocomposite material from renewable resource based derivatives is cost-effective, abundantly available, biodegradable, and an environmentally benign alternative for corrosion prevention. The aim of this article is to provide a comprehensive review and to bridge the gap by developing a new hybrid-biocomposite with superhydrophobic surfaces.

• 자원ㆍ환경경제연구
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• 제10권4호
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• pp.591-617
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• 2001

For the past years, there had been some environmental cooperation among East Asian countries to reduce air pollution emissions from China. However, the progress of cooperation has been under developed because of lacking financial support, poor design of planning, and weak economic incentives for the industries. In this paper, some practical approaches have been suggested. First, electric trade to make Asian Grid among countries will be good alternatives for the fossil fuel, such as coal, for China. Secondly, natural gas pipeline from West China to Siberian pipeline would change the whole energy mix in this area around 2010, Therefore, it is very promising area for the energy industries to involve in gas project and get rid of many institutional barriers from China. Lastly, environmental industry is growing fast in East Asian. In China, waste treatment and management, air pollution control, and water quality management are some promising areas for the future. Hence it is desirable for Korea, Japan and China to make a eco-fund or company to boost up environmental technology as well as environmental market size.

• Asian Journal of Atmospheric Environment
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• 제8권1호
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• pp.15-24
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• 2014

The capital city of Himalayan Country Nepal, Kathmandu Valley is surrounded by consecutive high mountains, which limits the air distribution and mixing effects significantly. It in turn generates steady air flow pattern over a year except in monsoon season. The air shed in the Valley is easily trapped by the surrounded mountains and the inversion layer formulated as the cap. The $PM_{10}$ concentration was noticeably higher than the standard level (120 ${\mu}g/m^3$) in urban and suburban area of Kathmandu valley for all seasons except monsoon period. The Valley area experiences similar wind patterns (W, WWS, and S) for a year but the Easterly wind prevails only during the monsoon period. There was low and calm wind blows during the winter season. Because of this air flow structure, the air emission from various sources is accumulated within the valley air, high level of air pollution is frequently recorded with other air polluted cities over the world. In this Valley area, brick kilns are recognized as the major air pollution source followed by vehicles. Mostly Bull Trench Kiln (BKT), Hoffman Kiln and Vertical Shaft Brick Kiln (VSBK) are in operation for brick firing in Kathmandu valley where the fuels such as crushed coal, saw dust, and natural gas are used for processing bricks in this study. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) was used for screening and quantifying the potential impacts of air emission from firing fuels. The total Environmental Performance Score (EPS) was estimated and the EPS of coal was approximately 2.5 times higher than those of natural gas and saw dust. It is concluded that the crushed coal has more negative impact to the environment and human health than other fuel sources. Concerning the human health and environment point of view, alternative environment friendly firing fuel need to be used for brick industry in the kiln and the air pollution control devices also need to be applied for minimizing the air emissions from the kilns.

• 한국가스학회지
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• 제17권1호
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• pp.67-72
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• 2013

LNG Value Chain에서 액화플랜트는 고부가가치를 지니며 전체 Cost의 약 35%를 차지한다. 액화플랜트의 핵심기술은 액화공정이며, 여기서 발생하는 대부분의 Cost는 액화공정의 운전에 필요한 에너지 생성과정에서 소비된다. 액화공정의 에너지소비를 줄이기 위한 방법은 액화공정의 핵심공정인 액화사이클의 효율을 높이는 것이다. 세계적으로 널리 이용되고 액화 효율이 높은 LNG 플랜트의 액화공정은 C3MR(프로판과 혼합냉매) 공정이다. C3MR 공정은 프로판 사이클과 혼합냉매 사이클을 이용하여 천연가스를 액화시키는 공정이다. 본 연구에서는 C3MR을 대상공정으로 하여 공정분석과 공정모사를 수행하였다. 이를 통해 C3MR의 공정변수를 알아내었으며 이후 공정최적화를 수행하였다. 본 연구에서 수행한 C3MR의 공정분석, 공정변수, 최적화 결과는 새로운 액화 공정개발에 활용 될 것으로 생각된다.

• 한국항해항만학회지
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• 제47권1호
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• pp.25-36
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• 2023

선박의 온실가스 감축을 위한 다양한 환경규제가 발효되었고, 이로 인해 액화 천연 가스(Liquid natural gas, LNG), 액화 석유 가스(Liquefied petroleum gas, LPG), 암모니아 그리고 바이오 연료 등 여러 대체 연료를 선박에 적용하고 있다. 대안 연료의 대부분이 액화가스형태의 저인화점 연료가 많이 거론되고 있고 그 사용량은 지속적으로 늘어날 것으로 예상된다. 이에 따라, 이러한 저인화점 연료를 선박 연료로써 이용하기 위한 표준이나 지침서가 필요한데 아직까지 미비한 실정이다. LNG의 경우, 벙커링과 관련하여 ISO 표준이 마련되었고 비영리민간기구(NGO)인 선박가스연료협회(Society for Gas as a Marine Fuel, SGMF)에서도 LNG 벙커링에 대한 지침서를 마련하여 발간하였다. 이와 더불어, 선급에서도 안전한 벙커링을 위해 벙커링 방법과 절차에 따라 안전관리구역을 지정하도록 하고 있다. 따라서, 연료에 따른 안전관리구역을 설정하기 위한 절차를 마련하고 절차 수립을 위해 벙커링 환경조건과 가스 누출 시나리오를 분석하고 이를 토대로 수치해석적 방법으로 검증이 필요하다. 본 연구에서는 이러한 절차 수립을 위한 초기 연구로써, 산업계의 적용 현황과 표준을 살펴보고 선급 지침서와 기존 선행 연구를 분석 및 조사하였다. 이를 바탕으로 국내 항만에서 벙커링을 위한 안전관리구역 설정을 위한 절차를 마련하고자 한다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권8_spc호
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• pp.1244-1255
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• 2019

Dairy goat production continues to be a socially, economically and culturally important part of the livestock industry in North, Central and South America and the Caribbean islands. Goat milk, cheese and other dairy products offer consumers food products with nutritional, health and environmental benefits. In North America, Mexico produces the greatest volume of goat milk, but most is for family or local consumption that is typical of a mixed farming system adopted by subsistence farmers in dry areas. The United States is not yet a large global goat milk producer, but the sector has expanded rapidly, with dairy goat numbers doubling between 1997 and 2012. The number of dairy goats has also increased dramatically in Canada. Commercial farms are increasingly important, driven by rising demand for good quality and locally sourced goat cheese. In South America, Brazil has the most developed dairy goat industry that includes government assistance to small-scale producers and low-income households. As of 2017, FAO identified Haiti, Peru, Jamaica, and Bolivia as having important goat milk production in the Western Hemisphere. For subsistence goat producers in the Americas on marginal land without prior history of chemical usage, organic dairy goat production can be a viable alternative for income generation, with sufficient transportation, sanitation and marketing initiatives. Production efficiency, greenhouse gas emission, waste disposal, and animal welfare are important challenges for dairy goat producers in the Americas.