• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.53-61
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• 2020

This study assessed the feasibility of coal mine drainage sludge (CMDS) as a stabilizing agent for mercury contaminated soil through pot experiments and batch tests. In the pot experiments with 43 days of lettuce growth, the bioavailability of mercury in the amended soil and mercury content of the lettuce were decreased by 46% and 50%, respectively. These results were similar to those of the soil amended with the sulfide compound (FeS) generally used for mercury stabilization. Thus, CMDS could be an attractive mercury stabilizer in terms of industrial by-product recycling. Batch tests were conducted to examine mercury fractionation including reactions between the soil and acetic acid. The result showed that some elemental fraction changed to strongly bounded fraction rather than residual (HgS) fraction. This made it possible to conclude that mercury adsorption on oxides in CMDS was the major mechanism of stabilization.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.41-47
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• 2009

Objectives : The objective of this study was to examine the effects of P. oleracea into the HCl-ethanol induced gastritis in rats, and to isolate and determine the chemical compounds from P. oleracea. Methods : The rats were orally administered with crude extract or fractions or isolated compounds of P. oleracea 30 mins before the induction of gastric lesion by oral administration of HCl-ethanol. The gastric lesional area was measured using pixel counting software. Then the chemical compounds from P. oleracea was isolated and determined by LC-MS and NMR. Results : The inhibition effect of oral administration of crude extract of P. oleracea at a dose of 500 mg/kg in HCl-ethanol induced gastritis was similar to cimetidine. Then, aqueous fraction at a dose of 240 mg/kg exhibited the effects similar to cimetidine. Then, the aqueous fraction was further separated by MPLC and yielded four sub fractions. Among those sub fractions, agent II at a dose of 40 mg/kg possessed the strongest effect in the HCl-ethanol induced gastritis. The water fraction yielded-Uridine, Adenosine, Guanosine, which were characterized by Mass, 1H-NMR, 13C-NMR. Conclusions : This study suggest that a P. oleracea and its compounds showed potent efficacy on the development of HCl-ethanol induced gastritis. Thus, P. olaracea can be a potential natural resource for the management of gastritis although the mechanism of action involved in the treatment remains to be explored.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.13 no.4
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• pp.230-236
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• 1984

This paper presents a method for estimating the useful output of solar D.H.W. system. Heating load calculations, climate data and various conditions are used in this procedure to assess the fraction of the monthly solar energy and the actual solar energy supplied by solar energy for particular system. The design procedure presented in this paper referred to the f-Chart Method. The results of analyzing of this study by Fortran programming are as follows ; 1 . The amount of actual solar energy required to the hot water system is slowly rised to the ascend of tilt angle within the range of $45^{\circ}$, with is decreased since $45^{\circ}$. 2. The fraction of solar energy is superior when collector area is $8.64m^2$. 3. At the tilt angle with the range of $37.6^{\circ}\~45^{\circ}$, the amount of actual solar energy established the best results. 4 Both the fraction of solar energy and the actual solar energy are the most suitable during the storage volume is $300{\iota}$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.11
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• pp.581-586
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• 2015

In this study, an analysis was performed on the performance of the solar water heating system with geo-thermal heat pump for a detached house. This system has a flat plate solar collector ($8\;m^2$) and a 3 RT heat pump. The heat pump acts as an auxiliary heater of the solar water heating system. These systems were installed at four individual houses with the same area of $100\;m^2$. The monitoring results for one year are as follows. (1) The average daily operating time of the solar system appeared to be 313 minutes in spring (intermediate season), and 135 minutes and 76 minutes in winter and summer respectively. The reason for the short operating time in summer is the high storage temperature due to low water heating load. The high storage temperature is caused by a decrease in collecting efficiency as well as by overheating. (2) The geothermal heat pump as an auxiliary heater mainly operates on days of poor insolation during the winter season. (3) Despite controlling for total house area, hot water consumption varies greatly according to the number of people in the family, hot water usage habits, etc. (4) The yearly solar fraction was 69.8 to 91.5 percent, which exceeds the maximum value of 80% as recommended by ASHRAE. So the solar collector area of $8\;m^2$ appeared to be somewhat greater for the house with an area of $100\;m^2$. (5) The observed annual efficiency of solar systems was relatively low at 13.5 to 23.6%, which was analyzed to be due to the decrease in thermal efficiency and the overheating caused by a high solar fraction.

• Journal of Environmental Science International
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• v.27 no.7
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• pp.597-610
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• 2018

This study observed particulate matter ($PM_{2.5}$ and $PM_{10}$) in the downtown area of Jeju City, South Korea, to understand the chemical composition of particulates based on an analysis of the water-soluble ionic species contained in the particles. The mass fraction of the ionic species in the sampled $PM_{10}$ and $PM_{2.5}$ was 44.3% and 42.2%, respectively. In contrast, in Daegu City and Suwon City, the mass fraction of the ionic species in $PM_{2.5}$ was higher than that in $PM_{10}$. The chloride depletion percentage of $PM_{10}$ and $PM_{2.5}$ in Jeju City was higher than 61% and 66%, respectively. The contribution of sea-salt to the mass of $PM_{10}$ (5.9%) and $PM_{2.5}$ (2.6%) in Jeju City was similar to that in several coastal regions of South Korea. The mass ratio of $Cl^-$ to $Na^+$ in the downtown area of Jeju City was comparable to that in some coastal regions, such as the Gosan Area of Jeju Island, Deokjeok Island, and Taean City. The mass fraction of sea-salt in $PM_{10}$ and $PM_{2.5}$ was very low, and the concentration of sodium and chloride ions in $PM_{10}$ was not correlated with those in $PM_{2.5}$ ($R^2$ < 0.2), suggesting that the effects of sea-salt on the formation of particulate matter in Jeju City might be insignificant. The relationship between $NH_4{^+}$ and several anions such as $SO_4{^{2-}}$, $NO_3{^-}$, and $Cl^-$, as well as the relationship between the measurement and calculation of ammonium ion concentration, suggested that sea-salts may not react with $H_2SO_4$, and $(NH_4)_2SO_4$ may be a major secondary inorganic aerosol component of $PM_{2.5}$ and $PM_{10}$ in Jeju City.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.32-32
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• 2010

본 논문에서는 대전입자층과 충전비율에 따른 구동특성을 평가하였다. 소자 제작은 동일한 cell gap에 대전입자의 입자층과 충전비율을 다르게 하여 패널에 주입하였으며 문턱전압 및 구동전압에서의 구간에서 실제로 움직이는 대전입자의 구동입자 개수와 면적을 측정하였다. 그 결과 대전입자층 및 충전비율에 따라서 구동전압 및 구동입자수와 white, black의 차지하는 면적비율의 차이가 있었으며, 면적측정으로 contrast ratio를 평가하고 실제로 구동하는 입자의 비율을 확인하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.241-246
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• 1996

An analytical model to calculate rate of vapor generation due to heterogeneous wall nucleation in flashing flow is developed. In the present model, an important parameter of the vapor generation term, i.e. nucleation site density is calculated by integrating its probability distribution function with respect to active cavity radius. The limits of integration are minimum and maximum active cavity radii, and these are formulated using an active cavity model for nucleate boiling. This formulation, therefore. can statistically account for the effect of surface specific thermo-physical and geometric conditions on the vapor generation rate and flashing inception. For verifying the adequacy of the present model, steady state two-fluid and the bubble transport equations are solved with applicable constitutive equations. The applicable region of the bubble transport equation is also extended to churn-turbulent flow regime to predict interfacial area concentration at high void fraction. Predicted results in terms of axial pressure and void fraction profiles along the channels are compared with experimental data of Super Moby Dick and BNL Reasonable agreements have been achieved and this shows the applicability of the present model to flashing flow analysis.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.166-166
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• 1998

Gliricidia sepium is a medicinal plant that has been established to have antidermatophytic activity. This research was able to isolate an antidermatophytic agent from the leaves of the plant. Leaves of Gliricidia sepium, locally known as kakaoati, were collected from the College of Science area of the University of the Philippines, Diliman, Quezon City. These were air dried, grounded and immersed in methanol. Different fractions were obtained by partitioning with hexane, chloroform, and ethyl acetate. These fractions were bioassayed to determine the fractions with the most antifungal activity using Trichophyton mentagrophytes as test organism. Inhibitory zone in millimeters was obtained and it was found out that the most active fraction was the hexane fraction with an inhibition zone of 25 mm as compared to chloroform with 16 mm and ethyl acetate with 18 mm.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.272-273
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• 2004

Filter media are one of themost important choices when bilfiltration is applied. Filter media provide adsorbing microbes with available sites for residence and the residential cells grow to degrade or decompose target waste gases. Up to date, filter media were only qualitatively analyzed. As a quantitative approach to filter material for biofiltration, a simple model based on reaction kinetics and mass action law (Ottengraf's Model in 1983) was presented. Cork, zeolite, and granulated activated carbon were tested in terms of effective surface area, cell covered fraction of adsorbing sites, surface roughness, and pore size distribution. The cell covered fraction, surface roughness and hydrophilicity was found to be closely related to the efficiency of gas degradation in biofiltration. The cork was the best candidate for cell residence and growth in this work.

• Transactions of Materials Processing
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• v.12 no.5
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• pp.449-456
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• 2003

Multi-step induction heating process was applied to the powder compact melting technique as a new heating process to achieve pinpoint accuracy, faster cycle time, repeatability, non-contact and energy-efficient heat in a minimal amount of time. The objective of this study is the establishment of the input data diagram of multi step induction heating process for automation of the fabrication process of 6061 Al foams with desired density. At first, proper induction coil was designed to obtain a uniform temperature distribution over the entire cross sectional area of specimen. By using this coil, foaming experiments were performed to investigate the multi-step induction heating conditions such as capacity, temperature and time conditions of each heating and holding step. On the basis of the obtained multi-step induction heating conditions, relationship between final heating temperature and fraction of porosity was investigated.