• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.759-762
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• 2008

A wastewater treatment plant located in coastal areas should be built considering the discharge of rainwater and treated water into the sea. The current Hagik Wastewater Treatment Plant in Incheon City was designed in the surface discharge method, which refers to discharging treated water directly into the sea. This method may cause hydrodynamic issues in a wastewater treatment plant because seawater enters an outfall riser when the level of discharged water is lower than the tidal level on a shore with high tidal range. In this study, a method for installing a weir in the discharge manhole was proposed in order to prevent seawater from entering the outfall riser of a wastewater treatment plant. Its feasibility was reviewed by calculating the hydrodynamic that had occurred due to the installation of the weir. As a result, seawater did not enter in the discharge manhole. Thus, even if the coast of Incheon City reaches the highest tidal level, treated water will be able to be properly discharged.

• The Korean Journal of Ecology
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• v.18 no.3
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• pp.419-427
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• 1995

This study was carried out to investigate the concentrations of Cu, Pb, Zn and in seawater, sediments and Mytilus edulis at Masan Bay, Onsan Bay, Daesan industrial complex and unpolluted area for the degree of contamination on the coast of Korea. The concentrations of dissolved Cu, Pb, Zn and Cd in seawater the ranges of 0.29~0.79 ${\mu}g/l$, 0.03~0.08 ${\mu}g/l$, 0.19~2.01 ${\mu}g/l$ and 0.01~0.05 ${\mu}g/l$, respectively. The concentrations of Pb(p<0.001) and Zn(p<0.01) showed the significant differences between the contaminated and unpolluted area. There were the ranges of 13~55 ${\mu}g/l$, 26~101 ${\mu}g/l$, 51~263 ${\mu}g/l$ and 0.8~2.2 ${\mu}g/l$ in the concentration of Cu, Pb, Zn and contaminated and unpolluted area. The concentration of Cu, Pb, Zn and Cd in the Mytilus edulis showed the ranges of 0.69~2.77 ${\mu}g/l$, 0.29~1.50 ${\mu}g/l$, 13.57~52.90 ${\mu}g/l$ and 0.09~0.85 ${\mu}g/l$ respectively. These concentrations of four trace metal in Mytilus edulis were not significantly different with sites. Trace metal contents of Mytilus edulis in the contaminated site were similar to those in the unpolluted area. This is thought that metal concentration in coastal seawater were not relatively serious.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.327-335
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• 2024

A simultaneous analytical method was developed to quantify antifouling agents and triazine herbicides in seawater using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The target compounds included diuron, irgarol 1051, and prometryn, which are prevalent in marine environments owing to their extensive use in antifouling coatings and agriculture. The analytical procedure involves solid-phase extraction (SPE) using HLB cartridges followed by LC-MS/MS analysis for precise quantification. The method exhibits high recovery rates for diuron (101% ± 1.25), irgarol 1051 (94.7% ± 2.08), and prometryn (93.7% ± 3.06). Seawater samples from 30 coastal sites in Korea were analyzed. Irgarol 1051 was not detected, whereas diuron was consistently detected across all sites, with concentrations from 0.68 to 11.3 ng/L, and prometryn was present at levels between 0.12 and 7.06 ng/L. The highest diuron and prometryn concentrations were recorded along the southeastern and western coasts, respectively. These findings underscore the critical need for continuous monitoring and regulations to manage these contaminants in marine ecosystems, thereby safeguarding ecological integrity and public health. This study establishes a robust analytical framework for the comprehensive assessment of multiple marine contaminants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.11-16
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• 2012

In coastal areas that are affected by continuous, seasonal or occasional pollution sources, bivalves accumulate biological contaminants such as pathogenic bacteria. We investigated the effect of natural seawater relaying and electrolyzed seawater depuration on the bacteriological quality of artificially contaminated oysters Crassostrea gigas and short-necked clams Ruditapes philippinarum to suggest an alternative method of shellfish sanitation control.When artificially contaminated oysters and short-necked clams (fecal coliform level 1,700 MPN/100 g) were relayed into a sea area of safe bacteriological water quality, the fecal coliform level dropped to below 110 MPN/100 g after 1 day. The bacteriological quality of oysters and short-necked clams that are contaminated at a fecal coliform level of 1,700 MPN/100 g could be improved, and become appropriate for raw consumption by a single day relay under proper environmental conditions. When artificially contaminated oysters (fecal coliform level 330 MPN/100 g) were depurated with electrolyzed seawater, 94% of fecal coliform was eliminated after 12 h and fecal coliform was undetectable after 24 h. After 24 h depuration with electrolyzed seawater, the fecal coliform level of short-necked clams with initial fecal coliform of 2,400 MPN/100 g was below 20 MPN/100 g. However, the fecal coliform level of short-necked clams with initial fecal coliform of 17,000 MPN/100 g was relatively high, at 790 MPN/100 g, even after 24 h of depuration with electrolyzed seawater, because of the repeated cycle of excretion and accumulation of fecal coliform in shellfish tissue under the closed depuration environment. Such natural seawater relaying and electrolyzed seawater depuration can be restrictively applied to improve or secure the bacteriological quality of oysters and short-necked clams in accordance with safety levels for bivalves for raw consumption.

• Journal of Power System Engineering
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• v.21 no.5
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• pp.20-28
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• 2017

The steady-state, incompressible and three-dimensional numerical analysis was performed to investigate the flow fields around the seabed tiller used for soil improvement in coastal fisheries and the pulling force and buoyancy generated by tiller operation. The turbulence model used in this study is a realizable $k-{\varepsilon}$. As a results, at a stationary current or a current speed of 1.2 knots, where rotor rotates in a clockwise direction, a typical vortex pair appears near the tip of the rotor except for the edge, and the strength of the vortex pair increases with the number of revolutions of the rotor. The pulling force of the tiller rotating in the counterclockwise direction increases with the number of revolutions. Also, when the current flows at 1.2 knots and the rotor rotates clockwise, the pulling force of the tiller acts on the upstream side irrespective of the number of rotations of the rotor, so that no force is applied. The buoyancy of the tiller acts on the seawater surface if the flow direction inside the rotor is the same as the direction of rotation of the rotor, regardless of the current velocity, otherwise it acts on the seabed.

• Wind and Structures
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• v.21 no.6
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• pp.597-607
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• 2015

With an increasing demand of a renewable energy, new offshore wind turbine farms are being planned in some parts of the world. Foundation installation asks a significant cost of the total budget of offshore wind turbine (OWT) projects. Hence, a cost reduction from foundation parts is a key element when a cost-efficient designing of OWT budget. Mono-piles have been largely used, accounting about 78% of existing OWT foundations, because they are considered as a most economical alternative with a relatively shallow-water, less than 30 m of seawater depth. OWT design standards such as IEC, GL, DNV, API, and Eurocode are being developed in a form of reliability based limit state design method. In this paper, reliability analysis using the response surface method (RSM) and numerical simulation technique for an OWT mono-pile foundation were performed to investigate the sensitivities of mono-pile design parameters, and to find practical implications of RSM reliability analysis.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.57-60
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• 2008

The flow of freshwater into the sea, termed as submarine groundwater discharge, is a key factor for understanding the hydrological cycle in both the sea and land regions. The numerous positions from which freshwater gushes out or its quantity impedes the understanding of its properties. Therefore, this study detects groundwater discharge points arising due to the difference in freshwater and seawater by using the multispectral Landsat ETM+ signals. A case study in coastal regions around Mt. Chokaisan, Japan is performed. This study comprises three procedures: (1) computer simulation of the flow of submarine groundwater discharge in the study area, (2) performance of preliminary experiment on the band properties of the Landsat ETM+, (3) detection of the difference in water properties by using the Landsat multispectral bands. Our experimental results obtained by the Landsat ETM+ are in considerable agreement with the realities in the study area.

• Korean Journal of Remote Sensing
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• v.17 no.2
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• pp.131-139
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• 2001

Extraction of waterline in tidal flat has been one of the main concerns in the remote sensing of coastal region. This study aimed to define the spectral characteristics of turbid water near the shoreline and to find the appropriate spectrum to delineate the waterline at the inter-tidal flat in the western coast of Korean Peninsula. Spectral reflectance curves were obtained by the field measurements under the diverse condition of water depth and turbidity at the study area in Kyong-gi Bay. Spectroscopy measurements showed that reflectances of the exposed mudflat, shallow turbid water, and normal coastal water were significantly different by wavelength. Shallow water near the waterline showed diverse conditions of turbidity. Spectral reflectance tends to increase as turbidity increases, particularly at the visible and near infrared spectrum. At the middle infrared wavelength, tidal water showed very little reflectance regardless of the turbidity and water depth and was easily disting from the exposed tidal flat. The exact waterline between exposed tidal flat and seawater should be extracted from the image data obtained at the middle infrared wavelength.

• Journal of Species Research
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• v.13 no.3
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• pp.310-317
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• 2024

Various samples from island and coastal ecosystems in South Korea were investigated to discover unrecorded bacterial species. Soils from these areas, along with seawater samples, were plated on marine agar and R2A agar (containing 3% sea salt). From these samples, approximately 1,070 bacterial strains were isolated as single colonies and identified using 16S rRNA gene sequences. A total of 20 strains, which exhibited at least 98.7% similarity in their 16S rRNA gene sequences to those of validly published bacterial species not yet reported in Korea, were identified as unrecorded bacterial species. These strains belonged to three phyla, six classes, 10 orders, 14 families, and 16 genera. These were assigned as follows: Thioclava, Breoghania, Acidovorax, Erythrobacter, Paracoccus, Jiella, Aurantimonas, and Qipengyuania within the class Alphaproteobacteria; Pseudomonas, Cobetia, and Rheinheimera within the class Gammaproteobacteria; Aequorivita, Leeuwenhoekiella, and Polaribacter within the class Flavobacteriia; Algoriphagus within the class Cytophagia; and Microbacterium within the class Actinobacteria. The unreported species underwent further taxonomic characterization, which included assessments of Gram reaction, colony and cell morphology, biochemical and phylogenetic characteristics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.15-20
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• 2006

It is well-known that the corrosive behavior of PMC (polymer matrix composite) structure is much better than the metal structure in the marine environment. The understanding of fracture behavior of PMC in the deep-sea environment is essential to expand its use in the marine industry. For a present study, fracture tests have been performed under low different pressure levels such as 0.1 MPa, 100 MPa, 200 MPa, and 270 MPa using the seawater-absorbed carbon/epoxy composite samples. Fracture toughness was determined from the work factor approach as a function of hydrostatic pressure. It was found that fracture behavior was a linear elastic far all pressure levels. The fracture toughness increased with increasing pressure.