• Resources Recycling
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• v.8 no.1
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• pp.11-17
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• 1999

This study was carried out to investigate the efficiency of stcclmaldng slag and sludge in removing metals existing in wastewater or leachate. Laboratory experiments were performed as a function of initial concentration of metals. pH a and temperature of the background solution and the presence of che1ating agent, EDTA. The test conditions were temperatures r ranging from $25^{\circ}C$ to $50^{\circ}C$; initial concentrations varying from 5mg/L to 50 mg/L; pH between 3 and 11; and Cu. Cd‘ and Pb a as adsorbates. The results of tests showed that overall rates of metals removal were 20~30% at pH 3 and greater than 90% at p pH 7 and 11. Metals were removed from the solution predominantly via adsorption in acidic conditions, and the combined e effects of adsorption and precipitation in neutral and alkaline conditions. In view of the test results and other engineering c characteristics of steelmaking slag and sludg$\xi$, these industrial by-products from steel industry have a high potential to be used l in wastewater treatment and are particularly beneficial when used as landfill liner additives due to thelJ ability to remove heavy m metals from leachate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.185-190
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• 2021

Cement has been used as a main material in the modern construction industry. However, it has been pointed out as a main cause of global warming due to carbon dioxide generated during manufactured. Recently, research that replacing cement substitute to industrial by-products such as Blast Furnace Slag which is by-producted in steelworks. When Blast Furnace Slag is used as a cement substitute, it shows a problem of lower initial strength, which is caused by glassy membrane on the particle surface. In this study, we used Electrolysis Alkaline Aqueous to improve the usability and problem of lower initial strength. As a result of the experiment, cement matrix using Blast Furnace Slag and Alkaline Aqueous showed initial strength and hydrate product were developed than that using general mixing water. Also, as a result of porosity analysis, It was confirmed that cement matrix using Alkaline Aqueous and Blast Furnace Slag has a tighter structure in internal porosity and porosity distribution than using general mixing water.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.66-74
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• 2021

The objective of this study is to evaluate the practical application potential and limitations of the modified fly ash(MFA) by vibration grinding as a partial replacement of ordinary portland cement(OPC). The test parameters investigated were the replacement level of fly ash(FA) and FA for OPC, varying from 10% to 40%, and curing temperatures of 5, 20, and 40℃. The various characteristics(including slump, air content, bleeding, setting time, compressive strength development, and hydration products) of MFA concrete were measured and then compared with those of the concrete with conventional FA. Test resul ts showed that the MFA prefers to FA in reducing the bl eeding of fresh concrete and enhancing the compressive strength gain at an early age. The compressive strength ratios between MFA and FA concrete specimens at an age of 1 day were 135%, 146%, and 111% at the curing temperatures of 5, 20, and 40℃, respectively. The corresponding ratios at an age of 28 days were approximately 110%, regardless of the curing temperatures. The X-ray diffraction analysis also revealed less calcium hydroxide products in MFA pastes than in FA pastes.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.554-562
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• 2022

Humans technological advancements have resulted in the depletion of whale resources. Accordingly, the International Whaling Commission was established to preserve whale resources and ensure the orderly development of the whaling industry. After a commercial whaling moratorium came into effect, the international trade of whale meat and related products was banned. However, There is a systematic activity through illegal remodeling ships because whales incidentally caught may be distributed in Korea and have a significant economic benefit. Although suspected illegal whaling is actively cracked down, but it is still insufficient to prevent illegal whaling and distribution. To prevent this, stereoscopic crackdowns utilizing air forces and patrol ships are effective, and it is necessary to quickly separate the captured ship and crew to prevent the destruction of evidence. For the transparent distribution of whale meat, it is necessary to advance related technologies such as whale species identification and individual identification of forensic science institutions based on whale DNA database of the National Institute of Fisheries Science. Accordingly, the Korea Coast Guard Research Center is directly conducting research on related national R&D project. To increase the efficiency of identifying whale-related evidence at crime scene, a rapid test kit that responds specifically to whale bloodstrains is developing and evidence transport packs are manufacturing and distributing, while identification technologies are also being advanced.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.18-25
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• 2022

MOF strengthen the law and institutions for safety management after the capsize accident of passenger ship "Sewol" on April 16, 2014. Nevertheless, about 13 cases of marine accidents such as collisions, contact, and stranding have occurred in coastal passenger ships over the past 5 years. Particularly, according to the judgment of KMST, most of the main causes of passenger ship accidents occurred within harbor areas because of the master's improper ship-handling or inattention. And so, this study analyzed four cases of marine accidents on passenger ships that occurred in the port areas and examined the environmental, institutional, material, and human factors that contributed to the master's improper ship-handling and behavior, and the results are as follows. First, as an environmental factor, the size of the turning basin was not enough. Second, as an institutional factor, the VTS control was not properly supported, the master lacked sufficient training for safe ship-handling in the port area and up-to-date charts were not provided. Third, as a material factor, the digital type speed log capable of the ship's speed in real-time was not installed on the ship's wing bridge. Lastly, as a human factor, the master could not take proper bridge resources and the passage plan was not proper. Therefore, it is suggested in this paper that the size of the turning basin should be adjusted to meet the prescribed standards, the master of passenger ships should receive the ship-handling simulation training among other safety training to ensure safe ship-handling of the master in the port area as improvement measures.

• Journal of Marine Life Science
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• v.1 no.1
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• pp.8-17
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• 2016

The family Pristiophoridae belonging to the order Pristiophoriformes consists of about 8 species and 2 genera in the world. Among them, only one species (Pristiophorus japonicus) is distributed in northwestern Pacific. The family is characterized by having an elongated and flattened rostrum with laterally projecting a low of sharp teeth. In order to clarify variability of local populations of P. japonicus, we investigated 16 individuals collected from four locations (Korea, n=6; Miyagi, n=1; Kochi Pref., n=1; Okinawa, n=8) for morphological and molecular analyses. Morphological analysis showed that there may exist three morphotypes, of which A morphotype (Korea, Miyagi, Kochi Pref.) has a short snout (26.8% of TL), being most similar to syntypes of P. japonicus. On the other hand, B morphotype (Okinawa) has a long (31.7% of TL) and wider snout (snout width at nostrils 5.2 times pre-oral length) and, C morphotype (Okinawa) has a long (31.7% of TL) and narrower snout (6.3 times). Molecular analysis using mitochondrial DNA cytochrome b DNA sequences (386 base pairs) showed that the K2P distance between A and C morphotypes were 2.1~2.7%, but those within A morphotype were 0.0~0.5%. We identified A morphotype as P. japonicus, and designated B and C morphotypes as Pristiophorus sp. 1 and Pristiophorus sp. 2, respectively. Further studies are required to elucidate the taxonomic status of two morphotypes of the sawshark in Okinawa.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.59-68
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• 2003

It's about time we had to think an alternative to recover our insufficient fishery market caused by IMF locally as well as the fishery agreement on Japan and China. It's essencial that we have to build up the foundation of information-oriented fishery market In order to improve the infrastructure of the market like developed countries. In this paper We present digital data communication network to exchange information for fishery and safety between fishing ship and coast station in cheeper communication fee using SSB(Sing Side Band) in HF(High Frequency) band.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.427-432
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• 2016

The purpose of the research was to examine the utilization of waste bittern from salt farm as a source for producing magnesium (Mg). In this work, a precipitation process for recovering Mg, where Mg is precipitated as $Mg(OH)_2$ by the addition of NaOH solution, was investigated. At the NaOH/Mg molar ratios of 2.70 : 1 to 2.75 : 1 and pH 9.5-10, > 99% of Mg could be precipitated from the bittern. The molar concentration of NaOH solution added as an alkaline reagent had no significant influence on the recovery efficiency of Mg precipitate. The particle size of Mg precipitate was strongly affected by the flow rate of caustic addition. The faster the flow rate of caustic addition, the smaller particles were formed. The Mg precipitate recovered was 100-120 g per 1 L of bittern and contained 94% $Mg(OH)_2$ after washing with water. Our results showed that the bittern can be used as a potential resource for Mg production.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.108-117
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• 2011

Old train carriages have been used to create artificial reefs (AR) as part of programs to enhance ocean fisheries and recreational resources. This study conducted hydraulic modeling experiments to estimate the structural stability of a train carriage AR. By applying fixed- and movable-bed conditions and Froude similitude, theoretical and hydraulic experiments revealed major design forces(e.g., water waves and currents). The results of this study showed that some dimensionless design parameters (e.g., surf similarity parameters, water particle velocity, scouring, and deposition) also affect the stability of an AR under various wave and current field conditions. In the fixed-bed condition, movement of the AR occurred when dimensionless water particle velocity based on the surf similarity parameter was larger than about 0.32. In the moveable-bed condition, the settlement depth (field values) of the AR ranged from 6 to 30 cm. The results indicated that characteristics of the sediment/bed condition and the direction of external forces acting on an AR should be considered when selecting AR sites.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.215-215
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• 2011

1996년도 UN해양법협약의 발효와 각국의 배타적 경제수역(EEZ) 선포로 연안역에 대한 관심이 국제적으로 고조되고 있는 가운데 우리나라에서도 연안역 관리법(가칭)이 제정되었다. 국토해양부는 연안역 공간이용 효율성 극대화와 부존 해양자원의 치계적인 개발과 보전을 위하여 연안역 관리법을 특별법으로 제정하였으며 1998년 중에 시행령 등 하위법령을 제정해 시행키로 하였다. 이 이후로도 연안역 특별법에 대한 연구는 계속 진행중이며, 현제 연안역은 연안어업, 수산양식장, 모래채취, 염전, 해수욕장, 관광지, 해양시설, 간척, 매립지, 공업단지 등으로 많이 이용되고 있다. 그러나 연안역 안전시설에 대한 상세 설계기준 및 시공에 대해서는 자세히 다루고 있지 않다. 연안역은 관광객이 증가하면서 안전시설과 구난장비의 미비한 실정으로 인해 인적 물적 피해가 빈번히 발생 증가하고 있는 것으로 나타나고 있다. 안전사고의 다발지역을 분석해 보면 관광객으로 인하여 방파제 주변에서의 안전사고가 증가하고 있는 상황이며, 이로 인한 인명피해도 증가하고 있다. 방파제에 대한 안전사고를 막기 위하여 우선적으로 방파제에 대한 안전사고를 해결하고자 인명피해를 막는 구난시설들에 대한 간격 등의 기준을 제시하였다. 다른 지역에 비하여 연안역은 파도에 의하여 사람이 떠내려가는 것을 고려하여 구난시설의 간격을 해안이나 다른 안전시설에 비하여 더 짧게 하였으며, 구난시설이 피해자에게 빠르게 전달되고자 멀리 던진 수 있으며, 구난시설을 잡음과 동시에 숨을 쉴 수 있는 여건이 조성되도록 연구하였다. 안전사고를 효율적으로 방지하기 위하여 인간공학을 접한 안전시설을 연구를 하였다. 인간공학이란, 인간의 행동, 능력, 한계, 특성 등에 관한 정보를 발견하고, 이를 도구, 기계, 시스템, 과업, 직무, 환경의 설계에 응용함으로 인간이 생산적이고 안전하며 쾌적하고 효과적으로 이용할 수 있도록 하는 것이다. 인간공학은 인간이 사용할 수 있도록 설계하는 과정에 있어 인간의 활용성 및 편리성을 증대하는 학문으로 보며, 설계초기 단계에서부터 인간의 요소의 체계적인 고려를 필요로 하게 되었다. 이 논문은 과거에 일어났던 사고사례들을 주시하면서 앞으로의 미래에 똑같은 사고사례가 발생하지 않도록 예방하이 위하여 인간공학과 안전시설을 통하여 연안역의 안전시설의 설치기준에 도움이 되는 자료를 제공하고자 한다.