• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.21-30
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• 2010

This study presents a numerical simulation of sea water-exchange as a preliminary accessing tool of water quality in the protected shore behind a overtopped breakwater. The overtopped breakwater is taken into account for a safe swimming and beach protection. The overtopping rate is calculated by empirical models and the consequent currents, known as wave-induced currents, are calculated under the conditions of H.W.O.S.T and L.W.O.S.T. The rate of sea water exchange is used to evaluate the characteristics of sea water exchange and calculated through the simulation processes such as advective discharging through the outlets and random-walking diffusion of particles released within a basin. The numerical results show that the overtopped waves sufficiently improve the water exchange without healthless stagnation of contaminated mass and the consequent currents are not too strong for swimming.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.419-422
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• 2005

This paper is examined the properties of Haeju sea sand for concrete. As result, the water absorbtion ratio and the contents of shell and microfines of Haeju sea sand was high. We would expected to utilize the results of this study as a basic data for quality control of Ready Mixed Concrete.

• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.259-263
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• 2011

This study explores ways to improve the actual conditions of ocean environment by conducting a comparative study on the current sea-water quality of Busan Metropolitan City and Incheon Metropolitan City that are representative sea port cities in Korea. The indices used to evaluate the sea-water quality include water temperature, salt content, PH, DO, COD, DIN, T-N, DIP, T-P, Sio2-Si, floating materials, and Chi-a. The findings of the analysis can be summarized as follows: First, ocean environmental states of Busan Metropolitan City and Incheon Metropolitan City are getting increasingly worse between the year of 2000 and 2003. Second, T-N, DIP and T-P have been main contributors in worsening ocean environmental states of Busan Metropolitan City and Incheon Metropolitan City.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.68-77
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• 2003

The Water quality of Namdae and Yeongok stream, located in the Kangnung City, and pollutants discharged to the east sea of Korea were investigated during april to November 2002 in order to understand the costal pollution phenomena. The water qualify grade of Namdae stream vary between II and V of water standard. On the other hand, that of Yeongok Stream is keeping I or II. The temporal and spacial variation of Namdae stream are higher than Yeongok stream. The water pollutants discharged to the east sea of Korea from Yeongok stream are lower 15.5 times for BOD, 2.6 times for COD, 1.7 times for T-N, 6.9 times for T-P than from Namdae stream, of which water flux are 1.4 times higher and contain much more of pollutants than Yeongok stream. It may have some effect on the costal ecosystem according to their pollutant flux.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.2 s.25
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• pp.75-79
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• 2006

In order to study the characteristics of water quality in coastal water and mechanism of phytoplankton blooms, factors of water quality were investigated in diatom bloom area due to rainfall event and no diatom bloom area Diatom blooms occurred after heavy rain and the dominant species were Skeletonema costatum($1,200{\sim}5,000cells/mL$) and Thalassiosira spp.($750{\sim}1,200cells/mL$). In diatom bloom area, water temperature, pH, and dissolved oxygen were observed at higher level than in no diatom bloom area Although these two areas were only 20 meters apart from each other, sharp difference in coastal water quality between two areas was observed. In diatom bloom area, concentrations of nitrogen, phosphorus, and silicate were observed at lower level than in no diatom blooms area. This seems to be due to inflow of much trace metal such as Fe, Mo, Se and so on than nitrogen, phosphorus, and silicate by rainfall events. However, distinct differences in DIN/DIP and $DIN/SiO_2-Si$ between these two areas were not observed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.2
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• pp.60-70
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• 1998

Masan Bay is a typical enclosed coastal sea and receving body of discharges from Masan city and Changwon city. A POTW(Publicly Owned Treatment Works) started operation from November 1993 when the population of drainage area increased abcent 1.0 million and the effluent from this Plant has being discharged to the enclosed sea where is located at 15km distance from inner Masan Bay. Thus the inflow pattern to Masan Bay has been changed. The main objective of this research is to evaluate the relationship between urban wastewater discharge and water qualify change in a typical coastal zone. It is necessary a) to evaluate the change of input loadings, b) to determine the effect on water quality changes, and c) to find the respective importance of improvement options that must be controlled in the wastewater treatment plant. It was concluded that the sea water quality has being adversely affected by the discharge of insufficiently treated urban wastewater and the nutrient removal in wastewater treatment was very important and urgent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.414-422
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• 2012

This study evaluated the effect of the inland pollution sources on the bacteriological water quality in Narodo area after rainfall events. Following 16 mm of rainfall, the water discharged from Dohwa Stream and contaminants from Balpo village had a very limited effect on bacteriological water quality in adjacent area and the affected area did not extend to the designated area. In comparion, after 33 mm of rainfall, the density of fecal coliforms at stations located in the mouth of Dohwa stream and the discharg point of contamination sources located in Balpo village were lower than after 16 mm of rainfall. These results were obtained during an extreme high tide near the coast the contaminants discharged from Dohwa stream and Balpo village. Therefore, it is necessary to conduct a detailed survey to examine the dffects of tides on the diffusion characteristics of the contaminants discharged from Dohwa stream and Balpo village in order to manage of Narodo area efficiently.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.157-160
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• 2006

Recently, trouble of sand supply is occurred according to exhaustion of natural sand resources. To solve this problem, sea sand and crushed sand are used. But, necessity of water reducing agent because quality of concrete that use sea sand and crushed sand is deteriorated. Therefore in this study was examined on the engineering properties of concrete with kind of fine aggregate and addition ratio of water reducing agents. As a result, compressive strength appeared similar standard regardless of kind of fine aggregate. Compressive strength, durability was similar in decrease of the unit water content by increase of addition ratio of the water reducing agent. Also, drying shrinkage resistivity was improved because the unit water content decreased.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.133-146
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• 1999

Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.24-29
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• 2003

Deep sea water has cold temperature, abundant nutrients and minerals, and good water quality that is pathogen-free and stable. Compared with surface water, deep sea water contains more nutrition salt, such as nitrogen and phosphor. Moreover, if has the good balance of minerals. Because of the ability of the spray drying process to produce a free-flowing power considering of spherical particles with a well-defined size distribution and the rapid drying times for heat-sensitive material, spray drying is attractive for a wide range of applications spray drying is a unique unit operation in which powders are produced from a liquid feed in a single processing step. Key component of the process are atomizer, spray chamber. Design of spray chamber should be based on the atomizer type, the production rate, and the particle size required. Because of the complex processes taking place during spray drying, traditional design method are based on pilot-plant tests and empirical scale-up rules. Modern technique such as CFD have a role to play in design and troubleshooting.