• Journal of Power System Engineering
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• v.19 no.2
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• pp.84-89
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• 2015

The occurrence of algae caused by eutrophication of fresh water is a pollution source to destroy the aquatic environment. When the high voltage electric field is applied in the water, When a high voltage is applied to the electric field in the water, the algae can be broken the balance of cell membranes, and is dead. In this paper, we develop a water quality improvement system for generating an electric field having a higher energy than the zeta potential when a high voltage is applied to 4,000V. To ensure the mobility of the water quality improvement system, we designed the PV generation system using the optimal size technique that is based on the model of power lack ratio. By evaluating the output characteristics of the water quality improvement system, power generation characteristics of the PV generation system, and battery charging characteristics, we can show that the proposed system can be applicable to the water quality improvement system inhibiting the growth rate of the algae in the fresh water.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.34-50
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• 2022

Since the Paris climate agreement, reducing greenhouse gases has been the most important global issue. In particular, it is necessary to reduce fossil fuels in the mobility sector, which accounts for a significant portion of total greenhouse gas emissions. In this paper, we investigated the economic feasibility of green mobility energy supply chains, which supply hydrogen as fuel to hydrogen vehicles based on electricity from renewable energy sources. The design and operation costs were analyzed by evaluating nine scenarios representing various combinatorial possibilities such as renewable energy generation, hydrogen production through water electrolytes, hydrogen storage and hydrogen refueling stations. Simulation calculations were made using Homer Pro, widely used commercial software in the field. The experience gained in this study could be further utilized to construct actual hydrogen energy systems.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.164-171
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• 2007

This experiment was conducted to investigate heavy metal speciation and bioavailability from soil to the edible parts of water dropwort near industrial complex. The soils and water dropwort were collected from the paddies cultivating water dropwort(10 sites), stream sediments(5 sites), and background soils(3 sites) near industrial complex. The total concentrations of Cd Cu, and Ni were higher than those of permissible level for soil contamination(Cd 3, Cu 100, Ni $50mg\;kg^{-1}$ in soil) suggested by Kloke(1979). Dominant chemical forms of Cd in paddies cultivating water dropwort and stream sediments were exchangeable form(49.1-56.3%), and those of Cu, Zn, and Ni were Fe and Mn oxide bound and residual forms. The mobility factor of heavy metals in paddies cultivating water dropwort and stream sediments was in the order Cd>Zn>Ni>Cu>Pb, specially, the mobility factor of Cd (62-72%) were relatively higher than that of other metals in soils. The total concentrations of Cd in soils showed significant positive correlation with the ratios of exchangeable and Fe and Mn oxide bound forms, while correlated negatively with residual form. Heavy metal contents in root parts were higher than those in top parts of water dropwort. The bioavailability of water dropwort varied considerably between the different parts and heavy metals. Cd, Cu and Ni contents in water dropwort were correlated with each fractions in soils. Specially, the exchangeable form of Cd and Ni in soils showed significant positive correlation with the those contents of water dropwort.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.350-357
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• 2005

This study was conducted to investigate the downward mobility of pesticides using soil columns and to compare the experimental results with values predicted from Convective mobility test model. Nine pesticides such as metolcarb, molinate, fanobucarb, isazofos, diazinon, fenitrothion, dimepiperate, parathion and chlorpyrifos-methyl were used for leaching test in soil column for four soils; Jungdong (upland soil), Gangseo (paddy soil), Yesan (forest soil), and Sineom(upland, volcanic ash-derived soil) series. The peak concentrations leached from 10 cm-columns of three soils except Sineom series ranged 6.5 to 12.6 mg/L for metolcarb, 2.6 to 5.0 mg/L for molinate, 4.5 to 7.8 mg/L for fenobucarb, 0.39 to 1.36 mg/L for dimepiperate, 1.1 to 4.6 mg/L for isazofos, 0.01 to 0.14 mg/L for diazinon, lower than 0.01 to 0.70 mg/L for fenitrothion and lower than 0.01 to 0.44 mg/L for parathion. But chlorpyrifos-methyl was not leached from any soil columns. Elution volumes to reach the peak of metolcarb, molinate, fenobucarb, isazofos, diazinon, and dimepiperate in the leachate ranged 1.1 to 2.1 pore volume (PV), 1.6 to 3.3 PV, 1.6 to 3.3 PV, 2.1 to 4.4 PV, 6 to 15 PV, and 8 to 21 PV, respectively. On the same water flux conditions, convection times estimated by Convective mobility test model were coincided with results from soil column test in most of the soil-pesticide combinations applied. Based on convection times estimated by the model at standard conditions (water flux 1 cm/day), metolcarb was classified as most mobile, molinate, fenobucarb and isazofos as mobile or most mobile, dimepiperate as moderately mobile or mobile, diazinon as mobile, fenitrothion and parathion as slightly mobile or mobile and chlorpyrifos-methyl as immobile or slightly mobile.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.316-329
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• 2005

Mobility of pesticides can be occurred by run-off and leachate or soil erosion. It is one of the most important factors for environmental contamination, particularly in steep sloped-land as Gangwon alpine region. In this study, the mobility of seven pesticides in different slopes and soil textures was investigated by simulated rainfall under controlled conditions. Simulated rainfall subjected to 60 mm $hr^{-1}$ was treated using rainfall simulator after 12 hr of pesticide treatment. Amounts of the pesticides were measured in run-off and leachate samples. The soil samples collected after rainfall from upper and lower parts and three different depths of sloped-plot were also analyzed. At result, all pesticides from the un-off samples collected from Taebaek(silty clay loam) and Heongseong(sandy loam) soils were detected maximum 96% within 60 minutes after first collection except carbendazim and cypermethrin which have the lowest water solubilities. From the leachate samples, a similar pattern was shown as run-off samples but amount of pesticides was lower than those of run-off samples. In soil samples, the order of the amount of pesticide residues was $0{\sim}5$ > $5{\sim}10$ > $10{\sim}15$ cm of soil depth and no pattern was shown in upper and lower, and different slopes. Comparing to mobility of pesticides in water and soil samples, pesticides in soil samples were higher than those of water samples in Taebaek soil. However, the results using Heongseong soils were in contrast to those of Taebaek soil. These results revealed that mobility of pesticides can be dependant mainly on soil textures and physicochemical properties of pesticides. Therefore, it can be suggested that selection of pesticides should be considered for soil texture and properties of pesticide in the alpine and sloped-land.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.6-8
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• 2001

This report describes the effect of the blending of poly(trifluoropropylmethylvinylsiloxane) (PTFPMVS) with poly(dimethylsiloxane) (PDMS) on the surface properties such as water repellency using dynamic contact angle (DCA) measurement. We have investigated the surface molecular mobility of the PDMS/PTFPMVS blends via a DCA measurement and an adhesion tension relaxation. It could be shown that a flexible side-chain segment in PTFPMVS having higher surface energy, could be reoriented easily in water to decrease the interfacial tension of the polymer/water interface, which seems to play a major role at the decrease of the receding contact angle and the surface resistivity of PDMS/PTFPMVS blends.

• Environmental Engineering Research
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• v.18 no.3
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• pp.177-189
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• 2013

Studies were carried out on the speciation of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) during rotary drum composting of water hyacinth (Eichhornia crassipes) for a period of 20 days. Five different proportions of cattle manure, water hyacinth and sawdust were prepared for composting. This study concluded that, rotary drum was very efficient for the degradation of organic matter as well as for the reduction of mobility and bioavailability of heavy metals during water hyacinth composting. The results from the sequential extraction procedure of heavy metals shows that rotary drum composting changed the distribution of five fractions of Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr. The highest reduction in the bioavailability factors of Pb and Cd was observed during the process. The total concentration of Cu, Cr, and Cd was very low compared to the other metals (Zn, Mn, Fe, Ni, and Pb); however, the percentage of exchangeable and carbonate fractions of these metals was similar to other metals. These results confirmed that the bioavailability of metals does not depend on the total concentration of metals. From this study, it can be concluded that the addition of an appropriate proportion of cattle manure significantly reduced the mobile and easily available fractions (exchangeable and carbonate fractions) during water hyacinth composting in rotary drum.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.336-336
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• 2004

EDTA contained in decontamination wastes can cause complexation of radioactive captions resulting from its various treatment process such as chemical precipitation, and ion exchange etc. It might also import for elevated teachability and higher mobility of cationic contaminants from conditioned wastes such as waste immobilized in cement or other matrices. Therefore, various cheated or unchlelated EDTAS must be treated to environmentally safe materials.(omitted)

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.59-59
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• 2010

Graphene has attracted much interest because of its fascinating electronic structure with excellent electron mobility. However, there are some difficulties in making graphene of large and uniform area for real applications. One alternative is graphite oxide. Since graphite oxide is water soluble, it can be sprayed or spin-coating onto any substrates for applications such as Transparent Conducting Film (TCF) and Field Effect Transistor (FET). In this talk, chemical and physical properties of graphite oxide will be discussed. In addition, possible applications made of graphite oxide (GO) will be introduced.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.182-186
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• 2001

An acid forest surface soil as a land farming medium was treated with a water plant alum sludge at 0 to 18%. Indian mustard was grown in the treated soil in a greenhouse for 5 weeks and watered with pH 4 tap water adjusted with a mixed acid (1HNO$_3$: 2H$_2$SO$_4$) during plant growth. Changes in soil property, leachate chemistry, plant growth, and plant uptake of elements by the sludge treatment were determined. The alum sludge treatment increased buffer capacity to acidity, hydraulic conductivity, water holding capacity, and phosphate adsorption of the soil and decreased bulk density and mobility of small particles. The sludge treatment reduced leaching of Al, Mg, K, Na, and root elongation. Plant did uptake less amount of the cations and P but more Ca with the sludge treatment.