• ALGAE
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• 제34권2호
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• pp.177-185
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• 2019

Ecklonia cava is popular in Korea as a marine functional materials. E. cava is generally collected and used on the coast of Jeju Island. However, the continuous use of collected natural E. cava may be limited because difficult to secure throughout the year and may be exposed to environmental pollution. Jeju magma seawater (MSW) was known to be significant advantages such as safety, cleanness, stability, and functional improvement. Attempts have been reported on application of MSW to the culturing of macro- and microalgae and showed improved results. Thus, the objective of the present study was to explore the anti-melanogenesis activity of brown seaweed E. cava (E. cava cultured with MSW [MSWE]) extract cultured in tanks with MSW of Jeju Island to evaluate the possibility of cosmeceutical industrial application. MSWE extract showed the higher polyphenolic and dieckol contents than natural E. cava (NE) extract. Anti-melanogenesis activity of MSWE extract and NE extract are tested and compared using tyrosinase and dihydroxyphenylalanine (DOPA) oxidation inhibition assay. MSWE extracts evidenced more effective tyrosinase and DOPA oxidation inhibition activity than that of the NE extracts and the commercial whitening agent, arbutin. MSWE extracts also markedly inhibited melanin synthesis and decreased the expression of melanogenesis-related protein in ${\alpha}$-melanocyte stimulating hormone-stimulated B16F10 melanoma cells without cytotoxicity. These results suggest that MSW cultivation process would be more effective in releasing bioactive compounds with whitening effect from seaweed such as E. cava at an industrial scale.

• 수산해양교육연구
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• 제27권6호
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• pp.1812-1821
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• 2015

In this study, we evaluate the eco-efficiency for recycling processes of Busan Resources Recycling Center for each year from 2010-2012. It analyze the impact of global warming on the power consumption by Life Cycle Assessment. Also calculate the economic value by net profit components those are sales amount and electric charge in accordance with the process operation. On the basis of these results, each of the eco-efficiency Factor analysis and dynamics analysis of 2011 and 2012 as the base year to 2010 are performed. As a result, the impact of global warming in all the recycling processes is increased by increasing power consumption 2010-2012. But net profit is decreased. In addition, the eco-efficiency of all the recycling processes is decreased and analysis result of the eco-efficiency trends is located on the Fully non Eco-efficiency (--) level. Therefore, all the recycling processes are necessary improvement for power consumption reducing and net profit increasing to further the environmental and economically sustainable direction.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1178-1184
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• 2008

In this study, techniques of ion implantation were used in order to improve the characteristics of metal materials such as the oxidation and wear resistant. In particular it is necessary to develope their oxidation and wear resistant that could be used in severe environmental conditions. There are mainly two elementary technologies including ion implantation and/or thin film coating. Ion implantation method was performed for surface modification. As a result, it was found that some ion implantations methods such as Nb, high-temperature Nb ion implantation and Nb+C combined implantation are somewhat effective for improving the oxidation resistance of TiAl alloy. Furthermore, the fluorine PBII treatment is more effective for improving the oxidation resistance of the TiAl alloy with three-dimensional shapes. The implantation of boron ion into thin film of TiN was also effective for improving the properties of materials like high temperature wear resistance. TiCrN film was applied to the actual seal ring for steam turbines, and it was observed that its sliding property showed a successfully good performance.

• 수산해양기술연구
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• 제53권2호
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• pp.115-125
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• 2017

Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear in fishing operation is generally related to hydrodynamic resistance on the gear. This research is to propose a low drag generated midwater trawl in terms of the gear design improvement using simulations. The results from the simulation were verified with results that mirrored the model experiments. From the results, the resistance force of the proposed gear decreased to 29% compared to that of the current gear. Furthermore, the gear performance also improved with increased gear mouth compared to the current one. Therefore, the proposed gear will be helpful to reduce the greenhouse gases from fishing operation. It will also contribute to the fishing industry by saving fuel.

• International Journal of Concrete Structures and Materials
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• 제9권4호
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• pp.487-498
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• 2015

A proper initial curing is a very simple and inexpensive alternative to improve concrete cover quality and accordingly extend the service life of reinforced concrete structures exposed to aggressive species. A current study investigates the effect of wet curing duration on chloride penetration in plain and blended cement concretes which subjected to tidal exposure condition in south of Iran for 5 years. The results show that wet curing extension preserves concrete against high rate of chloride penetration at early ages and decreases the difference between initial and long-term diffusion coefficients due to improvement of concrete cover quality. But, as the length of exposure period to marine environment increased the effects of initial wet curing became less pronounced. Furthermore, a relationship is developed between wet curing time and diffusion coefficient at early ages and the effect of curing length on time-to-corrosion initiation of concrete is addressed.

• 한국환경과학회지
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• 제22권11호
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• pp.1389-1402
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• 2013

This paper focuses on the impacts of waste dumping on inorganic nutrients in the dumping area of the Yellow Sea, and the effect of an governmental regulation of pollution in dumping areas. The environmental variables and parameters of the dumping and reference areas in the Yellow Sea were measured during July 2009 and analyzed. In addition, the analyzed data for inorganic nutrients over the last 10 years were obtained from the Korea Coast Guard (KCG) and the National Fisheries Research and Development Institute (NFRDI). The chemical environment of the study area revealed increases in concentrations of inorganic nutrients, Chemical Oxygen Demand (COD), and Volatile Suspended Solids (VSS) in the bottom layer. On the contrary, the pH level was decreased. Most notably, the time series data of inorganic nutrients showed gradual increase over time in the dumping area, and thus, the oligotrophic waters trend toward eutrophic waters. The increases appears to be due to the disposal of large amounts of organic waste. In recent times, the wastes disposed at the area were largely comprised of livestock wastewater, and food processing waste water. The liquefied waste, which contains an abundance of nutrients, causes a sharp increase in concentrations of inorganic nitrogen in the dumping area. On the one hand, the dumping sites have been deteriorated to such an extent that pollution has become a social problem. Consequentially, the government had a regulatory policy for improvement of marine environmental since 2007 in the dumping area. Hence, the quality of marine water in the dumping site has improved.

• 해양환경안전학회지
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• 제13권2호
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• pp.103-110
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• 2007

2003년 하계 진해만의 수질개선을 위한 육상오염물질 삭감량을 산정하기 위해 생태계 모델을 적용하였다. 모델에 의해 재현된 진해만의 수질은 마산만 측의 내측에서 해양수질 등급 III을 상회하는 수준으로 나타났으며, 등급 II의 수질로 개선하기 위해서는 육상부하를 50% 삭감하는 것이 효율적인 것으로 나타났다. 진해만 전 해역을 목표수질인 화학적 산소요구량 (COD) 농도 2.0mg/L을 만족하는 조 건은 전체 육상부하의 $70\sim90%$를 삭감하거나, 전체 육상부하와 저질 용출부하의 50%를 동시에 삭감하여야 하는 것으로 나타났다. 해역 II등급을 유지하기 위해 삭감해야 할 양은 유기물과 영양염을 동시에 삭감할 경우, 유기물 (COD) 5,632kg/day, 용존무기인 481kg/day 및 용존무기질소 7,991kg/day이며, 이 때 오염부하량의 한계 즉, 환경용량은 화학적산소요구량 부하 13,112kg/day, 용존무기인 206kg/day 그리고 용존무기질소 3,425kg/day 이라고 할 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제37권8호
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• pp.969-976
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• 2013

본 연구의 목적은 개방회로 공기스쿠버와 표면공급 잠수체계의 제한사항을 개선하기 위해 테크니컬 잠수기술을 적용하는 방안을 제시하여 한국 해군의 해난구조 활동 효율성 향상에 도움이 되는 기초자료를 제공하기 위함이다. 연구방법으로는 기존의 개방회로 공기 스쿠버의 제한사항을 개선하기 위하여 테크니컬 잠수기술을 이론적으로 고찰하고 개방회로 공기 잠수와 나이트록스(Nitrox) 잠수, 재호흡기(Rebreather) 간 가용심도, 무감압 한계시간, 수중 체류 가능시간, 감압의 효율성 등을 미 해군 등 공신력 있는 기관의 기준에 따라 비교 분석하였다. 그 결과 보다 적합한 테크니컬 잠수기술의 도입 방안이 도출되었다. 본 연구의 결과는 일련의 제한사항이 따르나 장비도입 및 교육 등 그 적용에 따라 감압절차 및 해난구조 활동의 효율성 향상에 기여할 할 수 있을 것으로 판단된다.

• 한국항해학회지
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• 제24권1호
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• pp.13-22
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• 2000

The collisions at sea among marine casualties are not reduced as the tonnage and speed of ship's increase as well as the traffic quantity increase at sea, in spite of the improvement of nautical equipment, enforcement of crew's education and training as well as improvement of quality standard according to the implementation of ISM code. The measures to prevent the collisions at sea are simple, and are composed of six stage.: The first stage is that the officer on duty detect the target from his eye or radar information. The second stage is determining the type and kind of target-ship. The third stage is target tracking; calculation of target speed, course, CPA and TCPA from radar information or visual check. The fourth stage is determination of vessel in danger after calculation of third stage. The fifth stage is the judgement of situation if own ship is stand-on or give way vessel according to the 1972 COLREG. The last stage is to carry out proper action according to 1972 COLREG, under the circumstances. But by the case, the situations are so different under the different external conditions; for example, natural/navigational conditions, crew's human factors, ship's particular, rule or regulation, management system on board, the condition of watch keeping. Therefore the reasons and casualties are so complicated. This study aims to investigate the collision casualty at sea which needs to clarity all these causal factors of afore-mentioned, and to analyze the causes of problems so as to utilize them to establish the measures of preventing marine accidents. This study, described the concepts of causal factors into three groups; environmental factor, and company/on board management system and navigator's act. Also described how to investigate and analyzes the casual factors. Even though it was described in this paper how to detect the causal factors and reasons of collisions, and how to analyze the inter-relation of each causal factors, it is necessary to do further study how to analyze between the liability of concerned parties and the casual factors involved.

• 한국지반환경공학회 논문집
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• 제13권6호
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• pp.83-90
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• 2012

일반적으로 심층혼합공법에 의한 점토지반의 개량효과는 물리적 개량효과에 비해서 훨씬 크며 조기에 큰 개량 강도를 얻을 수 있으나, 국내 시공실적이 부족하고 시멘트-점토의 혼합방법에 따른 품질관리에 문제점이 있는 것으로 알려져 있다. 본 연구에서는 시멘트, 모래, 점토의 배합비에 따른 강도특성과 연직MAT의 형태에 따른 연약지반의 개량특성을 파악하기 위해 해성점토를 이용하여 일축압축 강도시험과 모형토조시험을 수행하였다. 일축압축강도 시험을 위한 공시체는 시멘트와 물의 중량비를 기준으로하여 모래를 일정 비율로 혼합하였고, 시멘트는 점토중량대비 각각 10%, 20%, 30%, 40%를 혼합하였고 대상지반토의 함수비는 40%, 60%, 80%로 조정하여 제작하였다. 공시체는 습윤방법을 이용하여 7일, 14일, 28일간 양생하여 양생기간에 따른 일축압축강도시험을 수행하였다. 지지력시험은 모형토조를 제작하고 Mat식으로 개량한 지반을 형성한 다음 개량률에 따른 지지력을 비교하고 연직MAT 장벽 상호간의 간섭효과를 분석하였다.