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        검색결과 10

        1.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate of changes for organic acids in takju during storage conditions. Two types of takju, unsterilized and sterilized, were used. Acetic acid, citric acid, lactic acid, malic acid and succinic acid were detected in sample. Residues of malic acid was not detected after 7 days storage in room temperature( 25oC). In contrast to lactic acid was increased by times after storage. Acetic acid concentrations was gradually increased in room temperature but was not changed in cold temperature(4oC). After storage for 10 days, the organic acid residues lactic acid > citric acid > succinic acid > malic acid > acetic acid in unsterilized takju. Compared to unsterilized sample, organic acid residues in sterilized sample was not significantly changed. Consequently, organic acids residues mainly affected by sterilization.
        4,000원
        2.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Water quality in Nakdong river was analyzed using 699 monitoring data sets including flow rates and water quality concentrations collected at 195 tributary monitoring stations (the priority management areas: 35 stations, the non-priority management areas: 160 stations) in 2015. The highest average concentrations of all data for BOD, COD, T-N, T-P, SS, and TOC were 30 600 times higher than the lowest concentrations while the highest average loading rates were 800,000 2,700,000 times higher than the lowest loading rates. Because of the very large differences in the concentrations and loading rates, the variation of the concentrations and loading rates in a priority management monitoring station for BOD, T-P, and TOC was analyzed using the coefficient of variation, the ratio of the standard deviation value to the mean value. For BOD, T-P, and TOC, the coefficients of variation for concentration were mostly less than 100%, whereas the coefficients of variation for loading rate ranged from 31.1% to 232.2%. The very big difference in the loading rates was due to the large variation in flow rates. As a result of this, the estimation of water quality at each monitoring station using the average values of the concentrations and loading rates might be not rational in terms of their representativeness. In this study, new water quality analysis methods using all collected monitoring data were suggested and applied according to the water quality standard in medium-sized management areas.
        3.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        In this study, ibuprofen(IBP) degradation by the photochemical (UV/S2O8 2-) and sonochemical (US/S2O8 2-) processes was examined under various parameters, such as UV (10~40±5 W/L) and US (50~90±5 W/L) power density, optimum dosage of persulfate ion (S2O8 2-), temperature (20~60℃) and anions effect (Cl-, HCO3 -, CO3 2-). The pseudo‐first‐order degradation rate constants were in the order of 10-1 to 10-5 min-1 depending on each processes. The synergistic effect of IBP degradation in UV/S2O8 2- and US/S2O8 2- processes could investigated, due to the generation of SO4 - radical. This result can confirm from the produced H2O2 and SO4 2- concentration in each processes. IBP degradation rate affected by the S2O8 2- dosage, temperature, power and anion existence parameters. In particular, IBP degradation rate increased with the increase of the temperature (60℃) and applied power density (UV:40±5 W/L, US:90±5 W/L). On the other hand, anions effect on the IBP degradation was negative, due to the anion play as a the scavenger of radical.
        4.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        Ultrasound and Surfactant aided soil washing process has been shown to be an effective method to remove diesel from soils. The use of surfactants can improve the mobility of diesel in soil-water systems by increasing solubility of adsorbed diesel into surfactant micelles. However, a large amount of surfactant is required for treatment. In addition, synthetic surfactants, specially anionic, are more toxic and the surfactant wastewater is hard to treat by conventional wastewater treatments even by AOPs. Ultrasound improves desorption of the diesel adsorbed on to soil. The mechanisms are based on physical breakage of bonds by hot spot, directly impact onto soil particle surface, the fragmentation of long-chain hydrocarbons by micro-jet and microstreaming in the soil pores. The use of ultrasound as an enhancement method in both anionic and nonionic surfactant aided soil-washing processes were studied. And all experiments were examined proceeded under CMC surfactant concentration, frequency 35 khz, power 400 W, Soil-water ratio 1:3(wt%), particle size 0.24 ~ 2mm and initial diesel concentration. 20,000 mg/kg. Combination with ultrasound showed significant enhancements on all the processes. Especially, nonionic surfactant Triton-X100 with ultrasound showed remarkable enhancements and diesel removal rate enhanced by ultrasound helps desorpting of surfactant adsorbed onto soils which prevented decreasing surfactant activity.
        5.
        2009.02 KCI 등재 서비스 종료(열람 제한)
        In this study, to stabilize the heavy metal in the contaminated soils, the column leaching test based on rainfall and pH value was performed by using coal mine drainage sludge(CMDS): which was generated during electrical purification of abandoned coal mine wastewater. Four types of testing column were used in this study. That were the CMDS and the heavy metal contaminated soils well mixed in 0 wt%, 1 wt%, 3 wt% and 3 wt% layered column. According to the investigation, when the influent pH was 5.5∼6.2, there were no heavy metal elution at all conditions, and when the influent pH was 3∼3.3, the order of Cu, Zn, Pb, Cr elution concentration was 3 wt% M(mixed)<3 wt% S(separation)<1 wt% M<0 wt% and the average elution concentration was quite low, the value was 0.005 mg/L. Therefore, CMDS can used as new stabilizer of the heavy metal in the contaminated soils.
        6.
        2008.02 KCI 등재 서비스 종료(열람 제한)
        The batch tests were performed to determine the ratio of Fenton reagent on diesel contaminated soil. The objective of a column test was to determine and optimize the hydrogen peroxide requirements for the remediation of a soil contaminated with diesel fuel. The batch test were done on 5 g diesel contaminated soil containing hydrogen peroxide (35%) and Iron (II) sulfate. The H2O2(g):Fe2+(g) ratio varied 1:0, 30:1, 15:1, 5:1, 1:1, with contact reaction time 120min. Initial diesel concentration were 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg. Average diesel removal from the contaminated soil is 97% after 2hrs. Results of this study showed possible application of without addition of iron source. In column test, treatment of a diesel-contaminated soil (initial diesel concentration: 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg) with hydrogen peroxide (35%) only was containing natural-occurring minerals. The time required for the column test was approximately 90min, 180min, 270min; column length was 5 cm, 10 cm, and 15 cm. The most effective stoichiometry (final diesel conc.: 200~300 mg/kg) of 0.2 g peroxide consumed/mg diesel degraded. Further investigation is required to identify the effect of soil organic matter and soil mineral.
        7.
        2008.02 KCI 등재 서비스 종료(열람 제한)
        Characteristic of wastes in a unsanitary landfill at the residential development site in H city, Kyunggi-do was investigated for the disposal of huge amount of wastes. The total amount of wastes was estimated at 117,000 ton and construction solid wastes and municipal solid wastes were detected together. The portion of combustibles was very low and soils, concrete wastes, and pebbles were the major components in landfilled wastes. Because the site was the residential development site, the landfilled wastes should be removed immediately for the construction. Therefore the way that the unsanitary landfill was excavated and the wastes were sorted into three categories such as soils, noncombustibles and combustibles was selected as the best method. Soils and noncombustibles could be recycled and sorted combustibles could be re-landfilled in a smaller area or incinerated.