• The Korean Journal of Pesticide Science
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• 제18권2호
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• pp.53-60
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• 2014

This study was conducted to investigate the changes of the residual amount in the leafstalk (end) and the fore-end (upper) portion of lettuce leaves during cultivation period to 14 days, 12 times in total (0, 1, 2, 3, 4, 5, 7, 8, 10, 12, 13 and 14 days) after spraying with boscalid and lufenuron. In the case of boscalid, the initial concentrations at 3 hours (0 day) of the leafstalk and the fore-end portion of lettuce leaves were 18.26 mg/kg and 84.97 mg/kg, respectively and the residual amounts were rapidly decreased to 0.31 mg/kg and 0.37 mg/kg at 14 days after chemical application. In the case of lufenuron, the initial concentrations at 3 hours (0 day) of the leafstalk and the fore-end portion of lettuce leaves were 0.91 mg/kg and 5.21 mg/kg, respectively and the residual amounts were rapidly decreased to 0.06 mg/kg and 0.09 mg/kg at 13 days after chemical application. The variations of the residual concentrations analyzing 12 times after spraying showed that the residual amounts of the leafstalk portion of lettuce leaves were less than its fore-end portion in boscalid and lufenuron. In additon, 9 kinds of pesticide including boscalid in 16 lettuce leaf (found to contain pesticide in 2013) showed that the residual amounts of the leafstalk portion of lettuce leaves were less than its fore-end portion as well.

• The Korean Journal of Pesticide Science
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• 제3권2호
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• pp.47-53
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• 1999

Photosensitizing activities of some photosensitizers (PS) for the artificial diminution of pesticide residues on horticultural crops were investigated. Five fungicides, iprodione, bitertanol, chlorothalonil, myclobutanil, and dichlofluanid were sprayed on apple and cucumber, followed by the application of each selected photosensitizer, and the samples were collected 0, 1, 3, 7, 15 days after the photosensitizer application and analyzed for the residual amounts. Of the 40 photosensitizers tested, six selected on the basis of the eliminating effect of pesticide residues were PS-1 (aromatic ketone), PS-2 (aromatic amine), PS-3 (quinone), PS-4 (inorganic compound), PS-5 (organic acid salt), and PS-6 (semiconductor photocatalyst). The residual amount of iprodione after 15 days of the application of PS-1 was 74% of that of the control. For bitertanol, the residual amount after 15 days of the application of PS-1 accounted for 78% of that of the control. The residual amounts of chlorothalonil after 1 day of the application of PS-1 and PS-2 accounted for 56 and 54% of those of the control, respectively. The residual amounts of iprodione on cucumber after 3 days of the application of the photosensitizers PS-1 and PS-2 were 44 and 67% of those of the untreated control, respectively. For myclobutanil, the residual amount after 15 days of the application of PS-6 accounted for 45% of that of the control. In case of dichlofluanid, the residual amount after 3 days of the application of PS-1 accounted for 44% of that of the control. Based on the results, PS-1 turned out to be the most promising photosensitizer for the accelerated photodegradation of the above fungicides on apple and cucumber.

• Journal of Environmental Science International
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• 제22권9호
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• pp.1105-1113
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• 2013

This paper attempted to estimate the emissions of HFC-134a from scrap truck as a result of measuring the residual quantities of HFC-134a in air conditioner of scrap truck. We measured the residual amounts in the scrap truck of 138 by applying commercial recover for refrigerants. The average residual rate(disposal-phase emission factor) is reported to be $44.3{\pm}3.3%$ within a confidence interval of 95%. Recent year model trucks exhibit the higher residual rates. Little variation, however, is observed in regard to vehicle size. The HFC-134a emission quantity from scrap truck in 2011 is estimated to be 55,908 $tCO_2$-eq that demonstrates 21.4% increase to compare with that in 2007. As the numbers of truck have increased dramatically during the last two decades, the emissions of HFC-134a from scrap truck would increase sharply in the next coming years. HFC-134a is a very high GWP greenhouse gas. therefore have to reduce the emissions from the scrap truck and need to find ways to recycle. The chemical compositions of refrigerants from scrap truck are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap truck could be reused as refrigerant.

• The Korean Journal of Pesticide Science
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• 제16권4호
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• pp.302-307
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• 2012

This study was carried out to elucidate residual characteristics of environment friendly agricultural material rotenone in chilli pepper and calculate processing factors by drying. The test material was sprayed twice onto chilli peppers at an interval of seven days and then the chilli peppers were harvested at 0, 1, 3, 5 and 7 days after final spray. Limits of quantitation (LOQs) of rotenone in fresh and dried chilli peppers were 0.03 and 0.07 mg/kg, respectively. Recoveries of the test material in fresh and dried chilli peppers ranged from 89.52 to 97.86% and from 85.76 to 91.61%, respectively. As a results of residual material analysis, amounts of rotenone in fresh and dried chilli peppers ranged from 0.03 to 0.39 mg/kg and from 0.07 to 0.75 mg/kg, respectively, representing that the residual amounts of rotenone decreased time-coursely. Processing factors of rotenone in fresh chilli pepper by drying were found to be from 2.03 to 3.13, indicating that the residual concentration of rotenone in dried chilli pepper increased from two to three times by drying. However, the reduction factor of rotenone in fresh chilli pepper by drying ranged from 0.38 to 0.59, representing that some of rotenone in fresh chilli pepper disappeared during the drying process.

• The Korean Journal of Pesticide Science
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• 제20권4호
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• pp.341-348
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• 2016

Residual patterns of fungicides fludioxonil and metconazole applied 2 or 3 times on wheat were investigated with consideration for their distribution rates in each compartment of wheat. Wheat samples collected at harvesting day were divided into three compartments such as grain, hull and straw, and the pesticide residue analysis was individually carried out to such compartments of wheat. The analytical methods of fungicide residues in wheat were acceptable, with recoveries of 84.3 to 113.3% and correlation coefficients of 0.1 to 4.7%. Due to the systemic characteristics, the residual amounts of metconazole in the grain part of wheat were greater as 0.13~0.17 mg/kg than those amounts (0.01-0.03 mg/kg) for fludioxonil. To absolute residue amounts of the fungicides in one wheat plant, their distribution rates in each compartment of wheat were the highest in straws (68.5-70.7%), followed by hulls (29.0-31.0%) and grains (0.2-0.8%).

• Journal of the Korean Society of Food Science and Nutrition
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• 제38권9호
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• pp.1258-1264
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• 2009

The removal effects of two commonly used pesticides of Bifenthrin and Metalaxyl during preparation and fermentation of kimchi were studied. The two pesticides were applied to Baechu cabbages intentionally for 20 seconds; the applied amounts of Bifenthrin and Metalaxyl were 3.02$\pm$0.09 ppm and 6.79$\pm$0.17 ppm, respectively. The Baechu cabbages were washed by water 3 times. Then the residual amounts of the two pesticides of Bifenthrin and Metalaxyl were measured and the removal rates were 21.7% and 16.1%, respectively. When Baechu cabbages were brined with 10% salt solution for 12 hours after the application of the two pesticides, the removal rates significantly increased to 98.7% and 60.8%, and when brined and washed 3 times by water, the removal rates even more increased to 99.7% and 73.4% respectively. Then we made kimchi and investigated the quantities of the residual pesticides during the fermentation at $4^{\circ}C$ for 3 weeks. The residual amounts of the pesticides in kimchi decreased in a time dependent manner, finally the amounts of the pesticides to 0.35$\pm$0.04 ppm and 0.48$\pm$0.06 ppm while the removal rates of the two pesticides were 57.8% and 81.0%, respectively. When the kimchi was fermented at $4^{\circ}C$ and $10^{\circ}C$ for 3 weeks, the removal rates of Bifenthrin were 57.8% and 72.2% and those of Metalaxyl were 81.0% and 85.6%, respectively. Consequently, it appeared that the residual pesticides can be removed during preparation, especially brining; the fermentation process of kimchi also removed the residual pesticides effectively, especially at higher temperature and long period.

• Fibers and Polymers
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• 제2권1호
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• pp.157-162
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• 2001

Dyebath used for metal complex dyeing of nylon microfiber was recycled to reduce the overall amounts of metal complex dyeing effluents. Instead of discharging the dyebath after each dyeing cycle, the residual dyebath was analyzed spectrophotometrically and reconstituted to the required concentration of dyes and auxiliaries. Dyebaths were reused eight times and the CIELAB coordinates of dyed samples were measured after each recycling. Color difference($\Delta$E*) between the sample dyed in the fresh bath and that from reused dyebath was maintained below 1.5. The levelness and fastness of dyed fabrics from recycled dyebath were not impaired either. Chromium content of each recycled dyebath was similar to that of the first residual dyebath.

• Transactions of Materials Processing
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• 제21권6호
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• pp.384-388
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• 2012

Sheet metal forming processes induce residual stress in the final product due to plastic deformation. The residual stress leads to elastic recovery of the formed part called springback, which causes shape errors in the final product. This error is a serious issue, especially for high strength steels, which are widely used in auto-body structures. Therefore, the evaluation of the amount of springback becomes critical for high strength steels. This paper investigates the springback behavior of DP780 steel sheets after the U-bending process using the geometry of the standard U-shape tool from the NUMISHEET'93 benchmark problem. The amounts of springback were measured as a function of the intrusion direction, forming speed and blank holding force.

• Nuclear Engineering and Technology
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• 제20권3호
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• pp.165-169
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• 1988

As a part of tandem fuel cycle feasibility study, the residual U and Pu nuclide contents of PWR spent fuels are computed using ORICEN2 code for each Korea Nuclear Unit and batch to investigate the potential of utilizing them as CANDU fuels. The annual and accumulated discharged amounts of U and Pu nuclides are computed for the PWRs from KNU 1 through KNU 10. The results of computation show that the spent fuels having 0.7-0.8 w/o U-235 are dominant and considerable amounts of fissile Pu are produced. The enrichment of U-235 is less than the expected 0.8-0.9 w/o U-235 since the burnups offered by KEPCO are higher than those of other PWRs.

• Environmental Engineering Research
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• 제17권4호
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• pp.217-225
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• 2012

In this study, the treatability of two target contaminants during the Fenton reaction, n-hexadecane and 1-methylnaphthalene, was evaluated as a function of the amounts of $FeCl_2$ and $H_2O_2$ injected into open and closed reaction systems. In the Fenton reaction of n-hexadecane and 1-methylnaphthalene, the mass recovery of the target contaminants was above 95% in the closed system. However, when the Fenton reaction was performed with high amounts of $H_2O_2$ and $FeCl_2$ injected in the open system, a reduction of approximately 40% of the initial mass of 1-methylnaphthalene was observed. This trend may be explained by the unique physical properties of 1-methylnaphthalene, which has higher volatility than n-hexadecane. Further, this trend was well correlated with the rise in high temperature at the initial reaction stage. Considering the mass recovery of the two target contaminants, the reaction temperature, and the residual concentration of $H_2O_2$ at different amounts of $FeCl_2$ and $H_2O_2$ injected, it can be suggested that the Fenton reaction should be performed with controlled conditions that can provide a suitable reaction environment between oxidant and contaminants.