• KIEAE Journal
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• v.5 no.3
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• pp.17-24
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• 2005

Until today, rainwater management was processed without disposing the peak discharge, which was due to rainfall, to provide stability against flood damage. In this process, the natural hydrologic cycle changed quickly, and because of this, some problems that could harm human beings and the environment arose. These problems need to be addressed accordingly. One of the proposals was to carry out decentralized rainwater management through a natural hydrologic cycle on site, including utilization, infiltration, detention, and retention of rainwater. This study aims to set the direction of applicable decentralized rainwater management to housing complex in Korea. Therefore, spacial properties in urban housing complexes were analysed such as the impervious area-to-land ratio, the green area-to-land ratio, artificial land-to-land ratio etc. As the result of this study, when a housing complex was small and developed by reconstruction, the impervious area, artificial land, the green area in the artificial land-to-land ratio were high. So, direction of decentralized rainwater management of these housing complexes is available to utilize and detain rainwater. On the other hand, those of big housing complexes in land development district were low relatively. So, direction of decentralized rainwater management of these housing complexes is available to infiltrate and evaporate rainwater.

• Journal of Industrial Technology
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• v.17
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• pp.73-77
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• 1997

This study aims to develop the combined septic tank for middle-small scale sewage treatment. The developed process were circular and separate type. The circular combined septic tank was controlled sludge discharge and could be modified the advanced treatment system. The separate combined septic tank was could be applicated wastewater that discharge flow was varied, and was could be maintained F/M ratio constantly. The optimum hydraulic retention time was about 16 hours.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.223-228
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• 1989

In this paper, the computerized interpretation of the analytical chemical data, especially GC/MS data, was performed for the purpose of prescreening of the target compounds. First, the data from the analytical instrument was analyzed to get the information about the retention time of the ISTD and the time inteval between the records. Second, the identification of the characteristic ion peaks was performed by calculating the ratio of the heights and the relative slope sensitivity of the characteristic mass abundance.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.138-143
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• 1993

The objective of this report is to investigate the effect of factors like the fineness modulus of sand , content of fly ash and slaked lime, binder/sand ratio, admixture dosage on the physical properties of mortar for finishing. The analysis was performed with design of experiment and air content, water retention and compressive strength were measured.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.418-425
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• 2015

Anaerobic Filters (AF) packed with porous ceramic floating media were operated at different operational conditions to identify the feasibility of the renewable bioenergy, methane production from swine wastewater and to verify the suitability of effluent from anaerobic filters for the subsequent biological nitrogen and phosphorus removal. Stepwise increase in organic loading rates (OLRs) or decrease in hydraulic retention times (HRTs) with influent TCOD concentration of 14,000 mg/L were utilized at mesophilic temperature. The maximum methane productivity of 1.74 volume of $CH_4$ per volume of reactor per day (v/v-d) was achieved at an hydraulic retention time (HRT) of 0.5 day (OLR 28 g TVS/L-d). Based on the biogas production, the highest total volatile solids (TVS) removal efficiency of 63% was obtained at an HRT of 3 days (OLR 4.67 g TVS/L-d), however based on the result from the effluent total chemical oxygen demand (TCOD) analysis, the highest TCOD removal efficiency of 75% was achieved. The effluent alkalinity concentration over the range of 2,050~2,980 mg/L as $CaCO_3$ at all operational conditions, could compensate the alkalinity destruction caused by nitrification. The effluent from the anaerobic filter operated under the HRT of 2 days showed the COD/TKN ratio of 15~35 and COD/TP ratio of 38~56. Therefore effluent C/N/P ratio is able to satisfy the optimum COD/TKN ratio of greater than 8.0 and COD/TP ratio of 33 for the subsequent biological nutrient removal.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.578-589
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• 1996

This study was performed to invstigate the effect of dietary protein level and source on cadmium intoxicification in rats. Forty-eight male rats of Sprague-Dawley strain weighing 171$\pm$3g were blocked into 8 groups of 6 animals according to body weigth, and were raised for 30days. Eight experimental diets different with cadmium(0ppm, 400ppm)and protein(15%, 40%) levels and protein source[casien, I.S.P.(isolated soy protein)] were given to animals for 30days. Food intake, weight gain, food efficiency ratio, liver weight, kidney weight and femur weight were lower in cadmium added group, and higher in high protein groups(40% protein) than medium protein groups(15% protein). But, dietary protein source had no influence on them. Cadmium concerntration of liver was higher in rats fed casein than I.S.P. groups, and cadmium concentration in intestine was higher in high protein groups. In femur both high protein and I.S.P.diets increased cadmium concentrations. MT concdentrations in liver, kidney and intestine were higher in cadmium added group, and kidney intestine MT concentration were higher in high protein group. Absorption and retention rates of cadmium were lower in rat fed I.S.P. than animal fed casein among medium protein groups and cadmium concentration in blood and liver of I.S.P groups were lower than casein groups. But absorption and retention rates of cadmium were similar in high casein and I.S.P. groups. Renal damage by cadmium administration was not seen in all groups. Absorption rates of zinc and copper competing with cadmium in absorption process were lower in high protein groups than medium protein groups and lower in rats fed I.S.P. than casein. In conclusion, weight gain, F.E.R, and MT concentraion of high protein groups were higher than those of medium protein groups and absorption and retention rates of cadmium were lower in high protein groups. From these results, it was shown that cadmium toxicity was alleviated by high dietary protein. Meanwhile, the effect of dietary source on the cadmium toxicity was different with protein level. In medium protein groups absorption and retention rates of cadmium were much lower in rats fed I.S.P. than casein. In high protein groups, cadmium toxicity was not influenced by protein source and absorption and retention rates of cadmium were not different between casein and I.S.P. groups.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1120-1127
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• 2011

A feeding trial was conducted to investigate the effect of dietary supplementation of Bacillus subtilis LS 1-2 grown on citrus-juice waste and corn-soybean substrate on growth performance, nutrient retention, caecal microbial population and intestinal morphology in broilers. Three hundred twenty d-old Ross chicks were randomly allotted to 4 treatments on the basis of BW in a randomized complete block design. Each treatment had 4 replicates of 20 chicks in each. Experimental diets were fed in 2 phases, starter (d 0 to 21) and finisher (d 21 to 35). Dietary treatments were; negative control (NC: basal diet without any antimicrobial), positive control (PC: basal diet added with 20 mg/kg Avilamycin), basal diet added with 0.30% Bacillus subtilis LS 1-2 grown on corn-soybean substrate (P1), and basal diet added with 0.30% Bacillus subtilis LS 1-2 grown on citrus-juice waste substrate (P2). Overall BW gain, feed intake and FCR were better (p<0.05) in PC, P1 and P2 treatments as compared to NC. Moreover, overall BW gain and FCR in PC and P2 treatments were greater than P1. Retention of CP, GE (d 21, d 35) and DM (d 35) were increased (p<0.05) in treatments PC, P1 and P2 compared with NC. At d 35, caecal Clostridium and Coliform counts were lower (p<0.05) in treatments PC, P1 and P2 than NC. Moreover, Clostridium and Coliform counts in treatment PC was lower (p<0.05) than P1. Villus height and villus height to crypt depth ratio in both duodenum and ileum were increased (p<0.05) in treatments PC, P1, P2 as compared to NC. However, retention of nutrients, caecal microbial population and intestinal morphology remained comparable among treatments P1 and P2. It is concluded that Bacillus subtilis LS 1-2 inclusion at 0.30% level had beneficial effects on broilers' growth performance, nutrient retention, caecal microflora and intestinal morphology. Additionally, citrus-juice waste can be used as substrate for growth of probiotic Bacillus subtilis LS 1-2.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.95-105
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• 1973

Sink (grain)-filling rates of IR667 line (Suwon 213 and 214) and local leading varieties (Jinheung and Paldal) were investigated in relation to sink-source ratio, sink-source distance, forms of photosynthates, and weather factors. The results are as follows. 1. IR667 line have higher maximum filling rate (g. grain/day. ear) and shorter duration to reach maximum filling rate than local varieties. The curve pattern of sink-filling rate was high and steep type in IR667 line and low and broad type in local varieties. 2. Weather factors seem to give little effect on the curve pattern of sink-filling rate. 3. The functional sink-source distance (actual sink-source distance multiplied by the contribution rate of leaf for grain production) was shorter in upper leaves (flag and 2nd leaf) for IR667 line, the upper leaf-dependent type in grain production, and was longer in lower leaves (3rd and 4th) for local varieties, the lower leaf-dependent type. Specially short first internode from top may contribute to the upper leaf depencency of IR667 line. 4. According to free sugar-starch ratio (sugar/starch) in the culm and leaf sheath IR667 line could be classified as the high sugar type and the local varieties as the high starch type. The ratio of transportable form (sugar) to non transportable photosynthate (starch) seems to relate with sink-filling rate. And high sugar type is expected to have higher efficiency for grain production in view of energy balance. 5. A hypothesis that the higher in the uniformity within the series of productive structure the more efficient in grain production is proposed and discussed in relation to productivity. 6. According to the pattern of percent nutrient retention of each leaf blade IR667 showed the central retention type and Jinheung showed the apical retention type and each retention type appears to be a cause of each canopy conservation pattern. 7. From the content and percent distribution of nutrient in various organ IR667 could be classified as the leaf sheath dominant type and Jinheung as the leaf blade dominant type. 8. The fact that the greater the percent translocation of nutrient into grain the greater the percent nutrient retention in leaf blade was held between nitrogen and phosphorus within a variety and between varieties within a nutrient (N, P or K).

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.449-454
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• 2014

The effects of food deprivation and feeding ratio on the growth, feed utilization and body composition of juvenile olive flounder Paralichthys olivaceus were investigated in 810 juvenile fish averaging 6.4 g in weight randomly distributed in 27 400-L flow-through tanks. A 3 [food deprivation: 8-week feeding without food deprivation (8W), 7-week feeding after 1-week food deprivation (7W) and 6-week feeding after 2-week food deprivation (6W)]${\time}3$ (feeding ratio: 100%, 95% and 90% of satiation, hereafter denoted by 100, 95 and 90, respectively) factorial design was applied. The weight gain of the fish was significantly affected by both food deprivation and feeding ratio. The weight gain of the fish under the 8W-100 treatment was higher than that of those under the 7W-95, 7W-90, 6W-100, 6W-95 and 6W-90 treatments, but did not differ from those of fish under the 8W-95, 8W-90 and 7W-100 treatments. The specific growth rate (SGR) and the feed intake of the fish were affected by both food deprivation and feeding ratio. However, the feed conversion ratio (FCR) was unaffected by both food deprivation and feeding ratio. The protein efficiency ratio (PER) was affected by the feeding ratio, but not by food deprivation. The protein retention (PR) was affected by food deprivation, but not by feeding ratio. Juvenile olive flounder subjected to 1-week food deprivation at 100% satiation (7W-100 treatment) achieved full compensatory growth.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.107-116
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• 2013

This study was undertaken to investigate the characteristics of retention and evapotranspiration in the extensive greening module of sloped and flat rooftops for stormwater management and urban heat island mitigation. A series of 100mm depth's weighing lysimeters planted with Sedum kamtschaticum. were constructed on a 50% slope facing four orientations(north, east, south and west) and a flat rooftop. Thereafter the retention and evapotranspiration from the greening module and the surface temperature of nongreening and greening rooftop were recorded beginning in September 2012 for a period of 1 year. The characteristics of retention and evapotranspiration in the greening module were as follows. The water storage of the sloped and flat greening modules increased to 8.7~28.4mm and 10.6~31.8mm after rainfall except in the winter season, in which it decreased to 3.3mm and 3.9mm in the longer dry period. The maximum stormwater retention of the sloped and flat greening modules was 22.2mm and 23.1mm except in the winter season. Fitted stormwater retention function was [Stormwater Retention Ratio(%)=-18.42 ln(Precipitation)+107.9, $R^2$=0.80] for sloped greening modules, and that was [Stormwater Retention Ratio(%)=-22.64 ln(X)+130.8, $R^2$=0.81] for flat greening modules. The daily evapotranspiration(mm/day) from the greening modules after rainfall decreased rapidly with a power function type in summer, and with a log function type in spring and autumn. The daily evapotranspiration(mm/day) from the greening modules after rainfall was greater in summer > spring > autumn > winter by season. This may be due to the differences in water storage, solar radiation and air temperature. The daily evapotranspiration from the greening modules decreased rapidly from 2~7mm/day to less than 1mm/day for 3~5 days after rainfall, and that decreased slowly after 3~5 days. This indicates that Sedum kamtschaticum used water rapidly when it was available and conserved water when it was not. The albedo of the concrete rooftop and greening rooftop was 0.151 and 0.137 in summer, and 0.165 and 0.165 in winter respectively. The albedo of the concrete rooftop and greening rooftop was similar. The effect of the daily mean and highest surface temperature decrease by greening during the summer season showed $1.6{\sim}13.8^{\circ}C$(mean $9.7^{\circ}C$) and $6.2{\sim}17.6^{\circ}C$(mean $11.2^{\circ}C$). The difference of the daily mean and highest surface temperature between the greening rooftop and concrete rooftop during the winter season were small, measuring $-2.4{\sim}1.3^{\circ}C$(mean $-0.4^{\circ}C$) and $-4.2{\sim}2.6^{\circ}C$(mean $0.0^{\circ}C$). The difference in the highest daily surface temperature between the greening rooftop and concrete rooftop during the summer season increased with an evapotranspiration rate increase by a linear function type. The fitted function of the highest daily surface temperature decrease was [Temperature Decrease($^{\circ}C$)=$1.4361{\times}$(Evapotranspiration rate(mm/day))+8.83, $R^2$=0.59]. The decrease of the surface temperature by greening in the longer dry period was due to sun protection by the sedum canopy. The results of this study indicate that the extensive rooftop greening will assist in managing stormwater runoff and urban heat island through retention and evapotranspiration. Sedum kamtschaticum would be the ideal plant for a non-irrigated extensive green roof. The shading effects of Sedum kamtschaticum would be important as well as the evapotranspiration effects of that for the long-term mitigation effects of an urban heat island.