• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.518-530
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• 2020

The present study concerns the stern slamming load of container carriers, with stern bulb arrangement variation. First, a series of wedge drop tests were conducted using simple wedge models with fixed deadrise angles, and tests with the cross-section models of practical container carrier sterns were followed. The deadrise angle of the simple wedge ranged from 0° to 10°. The pressure measurement results of the simple wedge drop tests were distributed between empirical formula and analytic solution, so the experimental setup was validated. In the cases of practical hull cross-sections, the water entry of the bulb prior to that of the transom resulted in characteristic water film generation and delayed pressure peak appearance. The trapped air between the bulbs damped the pressure in the twin skeg hull case, reducing the pressure peak and causing the pressure oscillation during water entry.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.691-701
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• 2010

As the water-cycle is transformed by increasing of the impermeable area in process of urbanization, decentralized rainwater management facilities(infiltration, harvesting and retention facilities) as source control are considered to be a method of restoring water-cycle of urban and reducing runoff. SWMM model was used to analyse the change of water-cycle structure before and after development in A new town watershed. Modified SWMM code was developed to apply infiltration facilities. The modified SWMM was used to analyse the change of water-cycle before and after infiltration trench setup in AJ subcatchment. Changes of the impervious area by development and consequent increase in runoff were analyzed. These analyses were performed by a day rainfall during ten years from 1998 to 2007. According to the results, surface runoff increased from 51.85% to 65.25 %, and total infiltration volume decreased from 34.15 % to 21.08 % in A newtown watershed. If more than 80 infiltration trenches are constructed in AJ subcatchment, the low flow and the drought flow increases by around 47%, 44%, separately. The results of this study, infiltration trench is interpreted to be an effective infiltration facility to restore water-cycle in new town.

• Membrane and Water Treatment
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• v.2 no.1
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• pp.39-49
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• 2011

We investigated about the utilization improvement of the PDMS and fluoropolymers by mutual application in environmental analysis. We were conducted the direct fluorination with mild condition on the PDMS films and analyzed its surfaces before and after fluorination. The results of FTIR and SEM analysis on the PDMS films showed that the film surfaces were fluorinated without irreversible deformation by the fluorination. During the fluorination, the measured contact angles of water and several alcohols on the PDMS films decreased with time and that of most alcohols decreased to 0 after 30 minutes. The surface energy of fluorinated PDMS films has increased by 2 times. Also, we investigated the influence factors on the change of permeation rate of water through PDMS tubes with time. It was observed that the change of permeation rate of water through PDMS tube was affected by temperature, water phase and spatial distribution of water. From these results, we could verify the principal causes of the decrease of permeation rate of water through PDMS tube with time and proposed a new experimental setup for reducing the variation of permeation rate of water less than 2%.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.675-684
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• 2000

A novel dry and wet deposition collector, which can overcome the several problems such as water evaporation cartridge cracks and high costs founded in the previous collector systems, has been constructed. ENVI-18 SPE adsorption cartridge has been used to measure atmospheric deposition of polycylic aromatic hydrocarbons (PAHs). A surrogate surface, consisted of water and methanol, was filled in the dry deposition funnel to simulate dry deposition onto water surface. A water supply system in order to compensat evaporation of the surrogate surface was used and it was consisted of a piston pump, a tubing pump, a overflow tube and a chamber system. A novel water vaporizing system to supply water onto the wet SPE cartridge system with a constant flow rate was developed. The novel water vaporizing system, consisted of a vacuum pump, a water supply reserviour and tube and a mini space heater, could prevent the PAHs adsorption cartridge cracks occurred in the previous collector and effectively adsorb PAHs. The novel dry and wet deposition collector showed a good adsorption, desorption, and recovery rates of PAHs. By reducing the number of pumps used and employing polypyopylene (PP) instead of teflon as a material of collection funnel, the total construction costs were much reduced as compared with the previous dry and wet deposition collectors.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.843-853
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• 2009

The sediment samples were collected from Seonakdong River and were analyzed for sulfide species such Acid Volatile Sulfide(AVS) and Elemental Sulfur(ES) and Chromium Reducible Sulfide(CRS). Then characteristics of the formation of sulfide species were investigated for six selected samples. Finally the relationship between environmental factors and sulfate reducing rate(SRR) was investigated using two selected samples. Concentrations of AVS and CRS were relatively high, which suggests that organics input to the sediments has been continued until recently and that potential of heavy metals leaching from the sediments is low. SRR in the sediments was closely related to fraction of fine particles(silt+clay) and also to dissolved organic carbon content of the sediment(DOCsed). The dependences of environmental factors such as organic content, temperature, sulfate concentration on the SRR was relatively strong in the selected experiments conducted with the samples from Noksan gate and Daejeo gate samples. The environmental factor dependencies were stronger in the Noksan gate samples than in the Daejeo gate samples, which is probably due to higher surface area of the Noksan gate sediments.

• Journal of Ginseng Research
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• v.38 no.2
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• pp.146-153
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• 2014

A systematic comparison of the physicochemical properties of white ginseng (WG), extruded white ginseng (EWG), red ginseng (RG), and extruded red ginseng (ERG) was performed. The aim of the present study was to identify the effects of the physicochemical properties of ginseng by extrusion cooking. The highest value of the water absorption index (WAI) was 3.64 g/g obtained from EWG, and the highest value of the water solubility index (WSI) was 45.27% obtained from ERG. The ERG had a better dispersibility compared with other samples. Extrusion cooking led to a significant increase in acidic polysaccharide and total sugar content but resulted in a decrease in crude fat and reducing sugar contents. Enzyme treatment led to a sharp increase in acidic polysaccharide content, especially the cellulose enzyme. Extrusion cooking led to a significant increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, and the increases in WG and RG were 13.56% (0.038) and 3.56% (0.026), respectively. The data of this study provide valuable information about the effects of extrusion on quality changes of EWG and ERG.

• Magazine of the Korea Concrete Institute
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• v.6 no.6
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• pp.135-142
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• 1994

The quality characteristics of concrete using super plasticizer in dornestlc rnarket are evaluat ed in order to put to practical use of high performance concrete with high mobility. high strength ard high durability. For this purpose, rune kmds of super plasticizer are compared and analyzed for the slump, air content. unit weight, water reducing percent and ratios of compressive strength wth admixture content. As a result, the optimum quantity of admixture content were obtained for ordinary and high strength concrete using super plasticizer.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.626-629
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• 2003

The water extracts of Hovenia dulcis Thunb. showed significant reducing alcohol concentration in blood and hepatoprotective acitivity against D-galactoseamine/LPS and CCl4-toxicity. The concentration of blood alcohol was decreased from 2hr after injected in rats with Hovenia dulcis extracts. The water extracts of Hovenia dulcis significantly inhibited the elevation of serum ALT, AST and LDH levels. In this study, we investigated the effect of Hovenia dulcis extract on reducing alcohol concentration in blood. Also the efficacy and toxicity of Hovenia dulcis extract were evaluated by in vivo and in vitro tests.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.89-94
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• 2011

The potential biological activities of water and ethanol extracts from two varieties of Rubus coreanus Miquel fruits produced in the Gochang-gun (GR) and Hoengseong-gun (HR) regions of Korea were examined. The hydroxyl radical ($\cdot$OH) scavenging activity, reducing power, lipid peroxidation inhibitory activity, and antiproliferative activity on cancer cells by these extracts were examined, and $\alpha$-amylase and $\alpha$-glucosidase inhibition assays were also performed. The EtOH extract from GR showed high hydroxyl radical scavenging activity ($EC_{50}=119.47{\pm}5.13\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=213.45{\pm}3.14\;{\mu}g/mL$) and a concentration dependence, with OD values ranging from 0.15 to 0.56 (50 to 200 ${\mu}g/mL$), for reducing power. The EtOH extract from GR has the highest antiproliferative activities on MDA-MB-231 and HepG2 cancer cells among four extracts. Meanwhile, all extracts showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results indicate that extracts from two varieties of R. coreanus fruits have significant antioxidant, anti-diabetic and anti-tumorigenic activities, which suggest these extracts could be a potential source for pharmaceutical.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.47-54
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• 1999

SRB(Sulfate Reducing Bacteria) converts sulfate into sulfide using an organic carbon source as the electron donor. The sulfide formed precipitates the various metals present in the AMD (Acid Mine Drainage). This study is the fundamental research on heavy metal removal from AMD using SRB. Two completely mixed anaerobic reactors were operated for cultivation of SRB at the temperature of $30^{\circ}C$ and anaerobic batch reactors were used to evaluate the effects of carbon source, COD/sulfate($SO_4^=$) ratio and alkalinity on sulfate reduction rate and heavy metal removal efficiency. AMD used in this study was characterized by low pH 3.0 and 1000mg/l of sulfate and dissolved high concentration of heavy metals such as iron, cadmium, copper, zinc and lead. It was found that glucose was an organic carbon source better than acetate as the electron donor of SRB for sulfate reduction in AMD. Amount of sulfate reduction maximized at the COD(glucose)/sulfate ratio of 0.5 in the influent and then removal efficiencies of heavy metals were 97.5% of Cu, 100% of Pb, 100% of Cr, 49% of Mn, 98% of Zn, 100% Cd and 92.4% of Fe. Although sulfate reduction results in an increase in the alkalinity of the reactor, alkalinity of 1000mg/1 (as $CaCo_3$) should be should be added continuously to the anaerobic reactor in order to remove heavy metals from AMD.