• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.324-329
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• 2004

Oxygen diffuses through the cation-specific membrane, reducing the coulomb yield of the fuel cell. In the present study, attempts were made to enhance current generation from the fuel cell by lowering the oxygen diffusion, including the uses of ferricyanide as a cathode mediator and of a platinum-coated graphite electrode. Ferricyanide did not act as a mediator as expected, but as an oxidant in the cathode compartment of the microbial fuel cell. The microbial fuel cell with platinum-coated graphite cathode generated a maximum current 3-4 times higher than the control fuel cell with graphite cathode, and the critical oxygen concentration of the former was 2.0 mg $1^{-1}$, whilst that of the latter was 6.6 mg $1^{-1}$. Based on these results, it was concluded that inexpensive electrodes are adequate for the construction of an economically feasible microbial fuel cell with better performance as a novel wastewater treatment process.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.241-249
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• 2013

Ethanolamine (ETA) is widely used for alkalinization of water in steam cycles of nuclear power plants with pressurized water reactor. When ETA contained wastewater was released, it could increase COD and T-N. The treatment of the COD and T-N from ETA wastewater was investigated using the GAC as particle electrodes in three-dimensional electrode reactor (TDE). This study evaluated the effectiveness of GAC as particle electrode using different packing ratio at 300 V. The results showed that GAC-TDE could reduce ETA much more efficiently than ZVI-TDE at the mass ratio of GAC to insulator, 1:2. Additionally, The effect of applied electric potential to COD and T-N reduction was investigated. The results showed the high COD, T-N reduction and current efficiency at the low electric potential. Using the GAC-TDE will provide a better ETA reduction with reducing electrical potential dissipation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.38-44
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• 1998

The skin permeation and the skin primary irritation of two UV filters from caprylic capryl triglyceride (oil), oil in water (O/W) and water in oil (W/O) emulsions, were evaluated. We selected octyl moth-oxycinnamate (OMC) broadly used in cosmetics and polymeric sunscreen agent (PSA, average MW: 2,000) synthesized by the coupling reaction of 2-ethylhexyl 4-hydroxycinnamate with poly vinylbenzyl chloride, as model UV filters. For in vitro skin permeation experiments, Franz diffusion cells (effective diffusion area:1.766cm) and the excised skin of female hairless mouse aged 8 weeks were used. Oil or emulsion containing UV filters was applied in the donor compartment. The skin primary irritation was evaluated with fe-male guinea pigs (8-10 weeks,350-400 g). In oil and emulsions, the skin permeability and the skin primary irritation of PSA were lower than those of OMC. The skin permeability of UV filters was lower when they were in oil-in-water emulsion (OIW) than water-in-oil emulsion (W/O). We suggest that O/W system would be more useful when compared with W/O system, and PSA could be a good candidate for a future sunscreen agent for reducing the skin irritation.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.676-685
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• 2012

As impermeable layer continues to increase with the urbanization process, direct input of nonpoint source pollutants into water bodies via stormwater has caused serious effects on the aquatic ecosystem. Potential applications of rain gardens are increasing not only as best management practices (BMP) for reducing the level of nonpoint source pollutants but also as an ecological engineering alternative for low impact development (LID). In this study, remediation performance of various planting types, such as a mixed planting system with shrubs and herbaceous plants, was assessed quantitatively to effectively manage stormwater and increase landscape applicability. The mixed planting system with Rhododendron lateritium and Zoysia japonica showed the highest removal performance of $76.9{\pm}7.6%$ and $58.4{\pm}5.0%$ for total nitrogen and $89.9{\pm}7.9%$ and $82.4{\pm}5.2%$ for total phosphorus at rainfall intensities of 2.5 mm/h and 5.0 mm/h, respectively. The mixed planting system also showed the highest removal performance for heavy metals. The results suggest that a rain garden with the mixed planting system has high potential applicability as a natural reduction system for nonpoint source pollutants in order to manage stormwater with low concentrations of pollutants and will increase water recycling in urban areas.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.592-598
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• 2007

The fuel charge is getting higher in navigation cost. Therefore, shipowners try to find the method for reducing oil consumption. ESS(Energy Saving System) is one of he method. ESS is the system consisted with two inverters, ESS control unit and monitoring system. Two inverters control two main sea water cooling pumps. In the ESS control Unit, the control algorithm finds optimized point to decrease a power consumption of main sea water cooling pumps. Monitoring system observes ESS not to work improperly. ESS is experimented in the laboratory with real condition and analyzed in every view. After experiment, the result of the experiment shows that the control algorithm works correctly and safely. ESS has a plan to be operated in the ship soon. In that case, additional devices are needed to connect ESS with cooling system of the vessel. So the development of addition device is needed and being studied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.26-31
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• 2006

This study was conducted to determine the optimum number of inter-rows according to distance of drainage furrow (DF) for running-off excessive-water stress (EWS) in paddy field. The most soil water potential was shown in high ridge (distance of DF by 70 cm) cultivation and the soil water potential showed increasing tendency in over four inter-rows cultivation by DF. The growth of soybean reduced by extended inter-row and its reducing level was high, especially, over four inter-rows (DF distance by 2.8 m) because of EWS. The photosynthetic rate decreased in the more extensive field by distance of DF at V5 and R2 stages, especially, in over four interrows cultivation. Also, root activity decreased at wider DF. The yield was reduced with wider distance of DF more extensively, the highest yield of 270 g per $m^2$ at the every row, but yield showed decreasing tendency at over the $4^{th}$ row (2.8 m) cultivation. Soybean cultivation in paddy field could be founded with DF of every other or $4^{th}$ row.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.679-684
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• 2011

One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different $SiO_2$, $Al_2O_3$ and $Fe_2O_3$ sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

• Resources Recycling
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• v.15 no.4 s.72
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• pp.60-63
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• 2006

Waste aluminum dross was leached with sulfuric acid to prepare alum used for water treatment product. The remained metallic aluminum in the waste aluminum dross was extracted into the solution to make aluminum sulfate solution. The solution could be used as alum for water treatment product after adjusting the required alumina concentration and the basicity. Comparing to the conventional method for alum using aluminum hydroxide, material cost could be saved in this method. Also, there is an additional merit in view of recycling of the waste aluminum dross by reducing the amount of waste dross to be landfilled.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.7-14
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• 2010

Alternative subirrigation way, capillary wick system (CWS) was tested to reduce labor cost, waste water, contamination of ground water, and use of fungicide compared to overhead irrigation system (OIS). CWS helped reduce remarkably the working hours for watering from 4 hours in OSI to just 5 minutes. Labor cost was saved 98% in CWS compared to OIS. By the physical characteristics of various growing media, 1 coconut coir+2 perlite (v/v) mixture was selected because it had an ideal distribution of three phase, e.g. 1 solid: 1 liquid: 2 gas phase. Medium mixture containing scoria had so high bulk and particle density to hurt root. In bark-containing medium, the liquid phase and the percent saturation of liquid phase with time elapsed was lower than that of other mixture. It meant that the mixture contained very low level of water. Application of CWS for cyclamen pot production played an important role in reducing the incident of fusarium wilt symptom from 18% in conventional over watering system to 4%. Cyclamen pot irrigated by capillary wick had shorter petiole and more leaves than those by overhead watering. As a result, this system was highly beneficial to get uniform pot products with high quality. It improved water and nutrient solution efficiency relative to conventional overhead irrigation system (OIS).

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.257-257
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• 2015

Carbon Capture and Storage with ocean sequestration is being considered as one of the most effective option for reducing the $CO_2$ net flux from atmosphere nowadays. But it is still possible for $CO_2$ substance to leaks out from transport pipeline or from the under seabed storage sites and causing damage to ambient environment. The behavior of liquid $CO_2$ under droplet shape would be strongly affected by the presence of other contaminants such as $SO_2$ comes from processing processes. This presentation shows the behavior in the sea water of pure liquid $CO_2$ droplets as well as droplets that consist of $SO_2$ substances. The study uses computational fluid dynamic models in comparison with experimental data from other previous researchers. Droplet of liquid $CO_2$ is assumed to be released at several depths in deep ocean, with other environmental conditions are set up respectively. All calculations are conducted with many different ratio of contaminant $SO_2$ to provide fundamental data of those particles rising characteristics. The effect of contaminants on the behavior of $CO_2$ droplets would be clearly shown through the results of particle deformation, terminal rising velocity happen due to buoyancy force driving from the difference in density of $CO_2$ substance and ocean water around.