• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.144-153
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• 2007

One of the most recent issues facing the pesticides regulatory process is the assessment of the potential for pesticides to leach through soil and appear in groundwater. Since Jeju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water, it is important to identify which pesticides are the most likely to result in groundwater contamination. The objective of this study was to assess groundwater contamination risk of 21 pesticides (12 insecticides, 6 herbicides and 3 fungicides) in Jeju soils using groundwater ubiquity score (GUS). Considering GUS estimated in 21 representative series of Jeju soils, generally herbicides showed relatively higher leaching potentials and insecticides showed lower leaching potentials. Groundwater contamination risk was higher in the order of bromacil > metolachlor > alachlor > linuron pretilachlor > butachlor for herbicides, carbofuran > ethoprophos > diazinone > dimethoate > penthoate > mecarbam > methidathion > endosulfan > fenitrothion > parathion > chlorpyrifos > terbufos for insecticides, and metalaxyl > chlorothalonil > triadimefon for fungicides. Among the tested pesticides alachlor, metolachlor, bromacil, ethoprophos and carbofuran were classified as the pesticides of very high or high groundwater contamination potential. Although the ranking of the leaching potential was essentially determined on the base of the intrinsic properties of the chemicals and environmental properties, variation of the relative groundwater contamination potentials of each pesticides in different soils were not significant. Therefore, the above ranking of groundwater contamination risk would be applied in most of Jeju soils. To lower the possibility of pesticide contamination of groundwater, the use of those pesticides classified as high or very high leaching potential should be strictly regulated in Jeju Island.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.1
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• pp.1-17
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• 2024

Analyzing the tunnel excavation behavior and its effect on the surrounding ground involves large deformation behavior. Therefore, in order to properly simulate the tunnel excavation process and rigorously investigate the actual effect of excavation on surrounding ground and tunnel structure large deformation analysis method is required. In this study, two major numerical approaches capable of considering large deformations behavior were applied to investigate the effect of tunnel boring machine excavation on the surrounding ground: coupled Eulerian-Lagrangian (CEL) and the automatic remeshing (AR) method. Relative performance of both approaches was evaluated through the ground response due to TBM excavation. The ground response will be quantified by estimating the range of the excavation damaged zone (EDZ). By comparing the results, the range of the EDZ will be suggested on the vertical and horizontal direction along the TBM excavation surface. Based on the computed results, it was found that the size of EDZ around the excavation surface and the tendencies was in good agreement among the two approaches. Numerical results clearly show that the size of the EDZ around the tunnel tends to be larger for rock with higher RMR rating. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional due to higher confinement stress around the excavation surface.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.610-617
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• 2016

Current study was performed to investigate the effect of morphological properties of black ginseng such as size and shape on the quality of black ginseng. The raw ginsengs were separated based on size (medium, large, and extra-large) and shape (straight ginseng, fibrous root ginseng). Subsequently, the raw ginsengs were steamed at $95^{\circ}C$ for 3 h and dried in the presence of heated air at $50^{\circ}C$ for 30 h. This process was repeated nine times for black ginseng production. The physiochemical properties such as the content of acidic polysaccharides, ginsenosides, and antioxidative activity were evaluated. Although minor difference in physiochemical properties such as acidic polysaccharide content in raw ginseng was observed, no statistical difference in the content of acidic polysaccharides, total phenols, and ginsenosides was observed during final black ginseng production based on size classification. The minor ginsenosides in fibrous root black ginseng, such as Rk3, Rh4, Rg3, Rk1, and Rg5 were higher in content than straight black ginseng. However, no correlation between the shape of ginseng and total phenol content and antioxidative activity was observed. Therefore, present results demonstrate that the difference in ginseng size in same-age and -production area does not affect the quality of black ginseng. Furthermore, difference in ginseng shape does not influence the overall quality of black ginseng. It is hypothesized that this study would be considered as supportive data for the production of high-quality black ginseng.

• Food Science and Preservation
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• v.12 no.6
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• pp.529-533
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• 2005

The respiratory characteristics of Korean fresh ginseng were investigated from the aspect of picking season, size, and storage temperature and period to get basic data for extension of shelf-life. The respiration rate of fresh ginseng picked in March was 4.09 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$. It was gradually increased to August, 7.88 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and then decreased continuously until November. Although the rate of fresh ginseng was different by picking season, the respiration quotient showed the same level, $1.03\~1.07$. Respiration rate by size was ranged from 3.47 to 5.69 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and smaller in the size was higher in the rate. $Q_{10}$ value of fresh ginseng was $2.68\~2.88$ when the temperature increased from $0^{\circ}C\;to\;10^{\circ}C$ and $1.77\~2.16$ from $10^{\circ}C\;to\;20^{\circ}C$, and it was slightly different by picking season. At the beginning of storage the respiration rate was 7.0 mL $CO_2/kg{\cdot}hr$ and it was .decreased to 3.38 mL $CO_2/kg{\cdot}hr$ after storage for 90 days at $0^{\circ}C$.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.721-728
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• 2006

Earthquakes are reported thai building structures have been colossal damaged, but before 1988 designed structures which were not applicate seismic design code have no seismic performance. Especially, for the apartment structures were indicated that it have no resist wall element of earthquake before 1988 designed structures. We have to evaluate for seismic performance this structures, therefore it will be retrofitted for seismic index sufficient structures. We performed seismic performance evaluation for model structures by MIDAS which is general structure analysis software. In this study, it was performed shaking table test to evaluate model structure which is reinforcement concrete and 5 floors for seismic performance index. We made specimens by similar's law and tested shaking table test. In the shaking table test it is not performed prototype model test because of space and equipment condition. So we had made scale-down model for 1/5 by similar's law. That's why it needs for the evaluation of performance. However, it is not possible to do an experiment of prototype owing to the shortage of space and the limit of an experimental instrument in the shaking table test. Then, modeling and reducing the part of prototype do the experiment. In this experiment a shaking table test is done and seismic performance of model structures is evaluated by using similitude laws for scale down specimen. As a result it is proved that non-seismic design structures need to retrofit since seismic performance shows life safe grade in 0.12g of an earthquake.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.337-346
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• 2020

Traffic jam and congestion in urban areas has caused the need to improve the utility of underground space. In response, research on underground structures is increasingly being conducted. Notably, a double-deck tunnel is one of the most widely used of all those underground structures. This double-deck tunnel is separated by the middle slab into the upper and lower roadways. Both vehicle load and earthquake load cause the middle slab to exhibit dynamic behavior. Earthquake-related response characteristics, in particular, are highly complex and difficult to interpret in a theoretical context, and thus experimental research is required. The aim of the present study is to assess the stability of a double-deck tunnel's middle slab of the Collapse Prevention Level and Seismic Category 1 with regard to the presence of vibration-damping Rubber Bearings. In vibration table tests, the ratio of similitude was set to 1/4. Linings and vibrating platforms were fixed during scaled model tests to represent the integrated behavior of the ground and the applied models. In doing so, it was possible to minimize relative behavior. The standard TBM cross-section for the virtual double-deck tunnel was selected as a test subject. The level of ground motion exerted on the bedrock was set to 0.154 g (artificial seismic wave, Collapse Prevention Level and Seismic Category 1). A seismic wave with the maximum acceleration of 0.154 g was applied to the vibration table input (bedrock) to analyze resultant amplification in the models. As a result, the seismic stability of the middle slab was evaluated and analyzed with respect to the presence of vibration-damping rubber bearings. It was confirmed that the presence of vibration-damping rubber bearings improved its earthquake acceleration damping performance by up to 40%.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.486-496
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• 2018

This study was conducted to confirm an effect of span length on bending properties of larch dimensional lumber in the four point bending test. The size of specimen in this study was 38 (width) ${\times}$ 89 (depth) ${\times}$ 3,600 (length) $mm^3$, and average air-dry density and moisture content of the specimens was $543.5kg/m^3$ and 10.5%, respectively. Visually graded No. 1 dimensional lumbers of 248 were divided by two groups to compare modulus of rupture (MOR) and modulus of elasticity (MOE). One group was tested in the four point bending test with span length of 1,650 mm, and other was tested with span length of 3,000 mm. While MOE was not different according to span length in 5% significance level, MOR was different in accordance with span lengths and was in inverse proportion to change of span length. Fifth percentiles of MOR in span length of 1,650 and 3,000 mm were 28.65 and 25.70 MPa, respectively. It was confirmed that the difference between MORs in each case increased as normalized rank increased. This is because of size effect in Weibull weakest link failure theory. Therefore, KS F 2150, in which there is only regulation about span to depth ratio of 15 or more, is needed to be revised to contain a method considering size effect for MOR. From the method, various results of bending test with different size of lumber could be used to determine design value of lumber.

• Fire Science and Engineering
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• v.22 no.5
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• pp.72-78
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• 2008

The mass loss rate and heat release rate of EPS sandwich panel cores were analysed using variable external irradiation level. The experimental materials were exposed to incident heat fluxes form 20 to 50 kW/$m^2$. For the measurement of mass loss rate and heat release rate, the size of specimen was $100mm{\times}100mm{\times}50mm$ and the samples were 3 different kinds. The combustion heat were carried out from the Oxygen bomb calorimeter and the mass loss rate and heat release rate were carried out from the Mass loss calorimeter according to ISO 5660-1. As the results of this study, the mass loss rate of Type A, B, and C were 2.7 g/$m^2s$, 2.8 g/$m^2s$, and 2.3 g/$m^2s$ and the heat release rate of Type A, B, and C were 58.23 kW/$m^2$, 47.19 kW/$m^2$, and 50.06 kW/$m^2$ respectively at the heat flux of 50 kW/$m^2$. In conclusion, when the heat release characteristics applied to a classification system of Canada, Type A and C can be classified grade C-3, and Type C can be classified grade C-2 from all data of this study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1738-1747
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• 2010

This report shows the analysis and design of tactical decision automation procedure and the result of core algorithm. Expecially scheme of analysis and design includes result of tactical decision supporting procedure analysis for target engagement to fire in refer to AFATDS. Tactical decision automation procedure has three phases like target analysis, target priority, fire unit decision, fire method and attack method. Target analysis creates base information to decide priorities and attack methods through target activity, size and protection status. Target priority and fire unit decision judge target priority and fire unit with unit status and operation mission basis of target priority. Fire unit and Attack method decide fire style according to the kind of fire and ammunition for effective firing achievement. Finally, we show the effective tactical decision automation procedure through making the algorithm of priority and air control.

• Clean Technology
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• v.19 no.4
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• pp.464-468
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• 2013

In this study, in order to increase solid content of coal water fuel (CWF), various experimental parameters (i.e., coal type, additive, particle size distribution, drying method) were evaluated. To investigate the drying method, specimen is compared to using flash dry, fluidized bed dry and oil deposit stabilized coal. Difference of the solid content between low rank coal and high rank coal in this case indicate that high rank coal exhibits more higher than 20% of the solid cotent. And specimen for dispersibility was prepared by using dispersing agent of 4 types. As a result, using the dispersing agent was shown 5% higher in sold content than the case of not using the dispersing agent. Efficiency of CWF was improved by using fine coal of 80% in the particle size distribution of coal. Result of CWF using drying methods of 3 types, oil deposit stabilized (ODS) coal dried and stabilized was effective 12% higher in sold content than raw coal.