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권대영 ( Dae Young Kwon ),손민수 ( Min Su Son ),김홍석 ( H S Brian ) 한국농촌계획학회 2014 농촌계획 Vol.20 No.4
The objective of this study is to estimate the economic value of official management and control for invasive insects and diseases in fruits. The direct and indirect effect of this control measure can be the changes in price of fruits and related goods, changes in export volume of domestic fruits, changes in total volume of fruit production, and reduce the risk in food safety. The contingent valuation method with the single-bounded dichotomous choice is employed to estimate each household`s willingness-to-pay (WTP) to maintain official management and control measures. The total number of sample consists 2,050 respondents between the ages of 19-60 years, and the survey is conducted using Web-based survey. The estimated results for mean WTP is 5,443won per month per household. Therefore, the total economic value of official management and control on fruit in Korea is estimated to be approximately 94.4 billion won per month.
권대영 ( Dae-young Kwon ),김동훈 ( Dong-hun Kim ),김준호 ( Jun-ho Kim ) 한국수처리학회 2020 한국수처리학회지 Vol.28 No.6
In the present study, water pipe corrosion was examined according to the pipe type and under various water quality conditions, including changes of pH and alkalinity, and high concentration of iron(Fe) and manganese(Mn). Specimens of three different representative water pipe types, steel pipes, galvanized steel pipes, and stainless steel pipes, were used to investigate the corrosion characteristics, while the water quality was varied from strongly acidic (pH 1) to strongly alkaline (pH 12). Samples were collected every day and their pH, Fe, and Mn concentration, hardness, and alkalinity were analyzed through a loop test. The corrosivity was estimated from the Langelier saturation index, which can be calculated by water quality analysis results. The corrosion rate was calculated through the weight loss of the sample. The corrosion index increased for the first three days regardless of the water quality, except for the pH 1.25 condition. The corrosion rate decreased significantly, because of the film either created by the reaction of the corrosion oxides or generated on the surface of the specimen. High concentration of Fe and Mn in the water led to actively occurring corrosion.
정수장 배출수 처리효율 향상을 위한 상등수 자동집수장치개발에 관한 연구
권대영 ( Dae Young Kwon ),최민규 ( Min Kyu Choi ),이의재 ( Eu Jae Lee ) 한국수처리학회 2015 한국수처리학회지 Vol.23 No.3
Recently, a novel system with high efficiency has been developed to drain only supernatant of residuals effectively from water treatment plant, which results in high removal efficiency in water treatment by enhancing the quality of residuals and recycling water. The system could positively cope with the variation of water quality by a monitoring device. It was also operated automatically by an auto-control program. The purpose of the present investigation is to evaluate the treatment efficiency of an auto supernatant drain system (ASDS) in treating the residuals from water treatment plant by operating pilot tests as well as column tests. The ASDS improved BOD of the water flowing into the residuals basin by 40.6% and that of the water flowing into the thickener by 90.8%. The improvement effect of COD by the system were 26.7% and 83.9% for the recycled water and the effluent, respectively. The system also improved 1.62 mgL-1 and 0.17 mgL-1 in terms of the mean TN and TP, respectively. The ASDS improved 4.56 % of the mean moisture content and 87.3 % of the mean recovery rate.
처리수의 전기화학적 특성에 따른 막오염도 평가에 대한 연구
권대영 ( Dae Young Kwon ) 한국수처리학회 2014 한국수처리학회지 Vol.22 No.2
In cross-flow microfiltration (CFMF), suspended particles deposit to form a cake layer on the membrane surface, which provides a resistance to permeate flow. The cake resistance, which plays an important role on the performance of CFMF, is mainly determined by the packing porosity of the cake and, the physical and chemical properties of particles. This study is aimed at understanding the porosity and the specific filtration resistance of the cake for a given condition. These properties have been studied using experiments under a constant permeate flux. Constant structure of cake as well as constant rate of particles deposition was obtained by controlling the permeate flux. Factors affecting the particles deposition and cake formation such as permeate flux and ionic strength were investigated. This study also adopted a force balance model to predict the deposition rate of particle and compare with the experimental results. Inter-particle forces (electric double layer repulsion force and Van der Waals attraction force) were incorporated into the calculation of cake structure (cake porosity and specific resistance) together with the equilibrium condition of hydrodynamic forces. The values of the porosity and the specific resistance of the cake calculated by the force balance model agreed well with the experimental data.
권대영,Kwon Dae Young Korean Chemical Society 1992 대한화학회지 Vol.36 No.1
Stereoisomers of trifluoroethylmandelate(mandelic acid trifluoroethylester) were synthesized from each isomer of mandelic acid and trifluoroethanol with p-toluene sulfonic acid in order to study the enantioselectivity of lipase in organic solvent. The products were identified by $^1H$ NMR and elemental analysis and their physical properties such as melting point, densities and specific optical rotations($[{\alpha}]_{25}{^D}$) were also characterized. $[{\alpha}]_{25}{^D}$ of (+)- and (-)-trifluoroethylmandelate were +74° and -75.4°, respectively. The trifluoroethylmandelate was found out to be as a good substrate for the transesterfication stereoselectivity of lipases in organic solvent. Any significant difference of the lipase catalyzed transesterification activity between (+)- and (-)-methylchloropropionate was not found, and even lipase activity of transesterfication was not found with high optical polar (+)-and (-)-methylmandelate. 유기용매에서 리파제의 입체특이성 반응연구를 위하여 리파제의 기질로서 trifluoroethylmandelate를 도안하고 이를 mandelic acid와 trifluoroethanol를 사용하여 알코올과 산에서 에스텔을 합성하는 방법을 도입하여 합성하였다. 합성된 물질이trifluoroethylmandelate임을 $^1H$ NMR과 원소 분석을 통하여 확인하였다. (+)- 와 (-)-trifluoroethylmandelate ($[{\alpha}]_{25}{^D}$)은 각각 +74.0°and -75.4°이었다. 이 합성된 기질을 이용하여 유기용매내에서의 리파제의 입체이성질체에 대한 transesterification 속도는 서로간에 상당한 차이가 나타났다. 반면에 $[{\alpha}]_{25}{^D}$가 낮은 입체 이성질체인 (+)- 와 (-)-methylchloropropionate에서는 리파제의 활성은 있었으나 차이는 없었으며, 높은 $[{\alpha}]_{25}{^D}$를 갖는 methylmadelate는 리파제의 활성도 없었다.
나현영,권대영,Na, Hyeon-Young,Kwon, Dae-Young 한국지하수토양환경학회 2011 지하수토양환경 Vol.16 No.6
In this research, soil analysis and adsorption were conducted, and compared with the water quality of bank filtration and river in terms of TS, TDS, SS, $NH_4$-N, $NO_3$-N, $NO_2$-N, Fe, Mn, BOD and $KMnO_4$ consumption for the development of bank filtration in Gimhae city. Analysis of soil showed high levels of Fe (470 mg/kg), Mn (80 mg/kg) and $NH_4$-N (15 mg/kg). Also, adsorption coefficient values (k and 1/n) were 0.00159 and 0.8714, respectively. This implies that the adsorption of the soil depends on organic matter. Water qualitiy of the river and the bank filtration revealed that the concentrations of TS and TDS almost didn't change but the concentration of SS decreased 84% through the bank filtration. $NH_4$-N in the bank filtration was detected more than 1 mg/L which might be due to agricultural activities in the research area. $NO_3$-N was close to the detection limit owing to the removal by the adsorption. $KMnO_4$ consumption and BOD of the river were decreased by the bank filtration 250% and 350%, respectively, while Fe and Mn were significantly increased by the bank filtration.