• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.47-53
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• 2011

$SF_6$ (Sulfur hexafluoride) possesses high GWP (Global Warming Potential) as sepcified by the IPCC (Intergonvernmental Panel of Climate Change). Recently, the recovery-separtion of $SF_6$ research area, including permeation properties studies using various membrane's materials and the practical operation of recovery-separtion using membrane of waste $SF_6$ gas is in the initial state. The separation efficiency of a single $SF_6$ and waste $SF_6$ mixture was evaluated using a PSF (polysulfone), PC (tetra-bromo polycarbonate) and PI (polyimide) hollow fiber membranes. According to the results of single gases permeation properties, PI membrane has the highest permselectivity of $N_2$ gas in $N_2/SF_6$ gas. Under the condition of P=0.5 MPa, the highest concentration of recovered $SF_6$ is 95.6 vol % in the separation experiment of $SF_6/N_2$ mixture gas by PC membrane. Under the operation pressure of P=0.3 MPa at a fixed retentate flow rate fixed of 150 cc/min, the maximum recovery efficiency of $SF_6$ is up to 97.8% by PSF membrane. From the results above, it is thought that the separation and recovery technique of $SF_6$ gas using membrane will be used as the representative eco-technology in the $SF_6$ gas treatment in the future.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.916-927
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• 2010

In general water treatment process, the disinfection process by chlorine is used to prevent water borne disease and microbial regrowth in water distribution system. Because chlorines were reacted with organic matter, carcinogens such as disinfection by-products (DBPs) were produced in drinking water. Therefore, a suitable injection of chlorine is need to decrease DBPs. Rechlorination in water pipelines or reservoirs are recently increased to secure the residual chlorine in the end of water pipelines. EPANET 2.0 developed by the U.S. Environmental Protection Agency (EPA) is used to compute the optimal chlorine injection in water treatment plant and to predict the dosage of rechlorination into water distribution system. The bulk decay constant ($k_{bulk}$) was drawn by bottle test and the wall decay constant ($k_{wall}$) was derived from using systermatic analysis method for water quality modeling in target region. In order to predict water quality based on hydraulic analysis model, residual chlorine concentration was forecasted in water distribution system. The formation of DBPs such as trihalomethanes (THMs) was verified with chlorine dosage in lab-scale test. The bulk decay constant ($k_{bulk}$) was rapidly decreased with increasing temperature in the early time. In the case of 25 degrees celsius, the bulk decay constant ($k_{bulk}$) decreased over half after 25 hours later. In this study, there were able to calculate about optimal rechlorine dosage and select on profitable sites in the network map.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.105-117
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• 2004

The purpose of this study was to examine the effect of aroma therapy on anxiety and pain before and after tooth extraction. The subjects in this study were 60 patients who felt severe anxiety and pain due to tooth extraction. The experiment was conducted from January through March, 2004, by organizing an experimental group and a control group with 30 patients each. The experimental group was asked to keep wearing lavender-containing necklaces from two days before tooth extraction to inhale lavender, and no such an action was taken to the control group. The collected data were analyzed with SPSS 10.0 program to obtain statistical data. and ${\times}2$ test and t-test were implemented. The findings of this study were as follows: 1. Regarding whether or not the experimental and control groups were homogeneous, men outnumbered women, and the largest number of the patients were in their 30s. Those who were married were more than the others who were unmarried in number, and those who lived with their spouses under the same roof together outnumbered the others who didn't, as the rate of the former stood at 65 percent in the experimental group and 86.4 percent in the control group. They expressed high satisfaction at their spouses, since 45 percent of the experimental group and 31 percent of the control group did it, but the difference between them and those who were unsatisfied was insignificant (pE0.347). By occupation, the largest number of people in the experimental group, which numbered 16.7 percent, were self-employed, and lots of patients in the control group were government workers. As for blood type, type A was most prevailing, which recorded 43.3 percent. By religion, 43 percent of the experimental group had no religion, whereas 36.7 percent of the control group were Christian. The most common monthly income ranged from 2 million to 2.5 million won. 2. There was little disparity in past pain experience between the two groups before aroma therapy was applied. The experimental group underwent more pain (6.15) than the control group (5.78), but the difference wasn't significant. The experimental group (90%) experienced more anxiety and fear than the control group(83%), but the difference was insignificant. This fact showed that there was little gap between the two groups in anxiety and fear caused by tooth extraction. Contrary to earlier expectation that pre-anxiety might not be the same. little significant difference was found. 3. After aroma therapy was applied, 50 percent of the experimental group and 23.3 percent of the control group suffered significantly less anxiety and fear about tooth extraction(${\times}2$=4.59, pE.05). And the experimental group exposed to aroma therapy was less nervous(3.0) than the control group(4.39), and the gap between the two was significant (t=13.37, pE.001). Therefore, aroma therapy had a good effect on alleviating their anxiety. During tooth extraction. 73.3 percent of the experimental group and 93.3 percent of the control group felt pain. The former group suffered Significantly less pain(${\times}2$=4.32, PE.05). Concerning the extent of pain, the experimental group(2.53) found it less painful to have their teeth extracted than the control group(5.50), and the gap between the two was significant(t=5.89, PE.05). 4. As to the effect of aroma therapy on alleviating anxiety or fear, the experimental group(33.3%) felt that aroma therapy let them more relieved. Every member of that group was willing to use aroma therapy again in the future, and 86.7 percent of that group perceived that aroma therapy made a difference to dental treatment. The experimental group responded to aroma therapy favorably, as every member of it had an intention to advise others to use that therapy.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.409-413
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• 2011

BACKGROUND: Cereals, especially rice is the staple food of oriental nations and because it is very important for Korean food, to determine the extent of nutrient losses due to milling, we analyzed the fatty acid using by GC-FID(Gas Chromatography-Flame Ionization Detector). Experimented rice cereals were rice, glutinous rice, Heuinchalssalbori, Seodunchalbori, Saessalbori, Keunalbori No.1, barnyard millet produced in Korea. METHODS AND RESULTS: After milling, the contents of fatty acids in the rice, glutinous rice, Heuinchalssalbori, and Seodunchalbori, Keunalbori No.1 rather decreased, but in the Saessalbori, and barnyard mille increased. Particularly, fatty acid content of the rice decreased from 24.8 mg/g to 6.4 mg/g, glutinous rice decreased from 29.4 mg/g to 11.7 mg/g after milling. There were also significant changes in the compositions of fatty acid among samples. Stearic acid ($C_{18:0}$) increased from 5% to 15%, but oleic acid ($C_{18:1}$) and linoleic acid ($C_{18:2}$) decreased in the rice after milling. CONCLUSION(s):In the brown rice, 11 different types of fatty acids were detected, and its highest content was found in grains. However, milled grain was observed only seven fatty acids in the case of rice. This result insisted that a portion of the lipid layer was significantly lost during the milling operation in rice.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.316-322
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• 2011

BACKGROUND: Pesticides concentration was monitored in 50 agricultural lakes, and ecological risk for aquatic organism was assessed using risk quotient (RQ) and probabilistic methods. METHODS AND RESULTS: Pesticides concentrations detected in 50 agricultural lakes during peak season (June and September) were in the range of $0.17{\sim}0.99{\mu}g/L$. The RQ for algae and the other species was estimated to be 0.25 and below 0.01, indicating medium risk and no risk. Oxadiazon predominantly contributed to RQ value of 99% for algae, fishes, and amphibians. In terms of hazardous concentration at 5% of species ($HC_5$), ecological risk quotients (ERQ) for oxadiazon ranged from 0.18~0.33, showing a medium risk level. Overall, the concentrations of pesticides were much lower than $HC_5$), value. Probability of combined ecological risk for pesticides ranged from 1.82% to 2.41%. CONCLUSION(s): Combined ecological risk probability did not exceed the acceptable level of 5%, indicating no ecological risk for selected aquatic species. This study suggests that regular ecological risk assessment (ERA) will be required to protect and manage an agricultural lake. Not only ERA at screening level by comparing exposure with toxic effects for aquatic species also advanced ERA technique considering species in indigenous to Korea, chronic toxicity, pulse dose, fate, and environmental factors should be required.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.304-309
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• 2011

BACKGROUND: Generally, water plants may play an important role in nutrients(N, P) removal in constructed wetlands(CWs). Previous studies considered nutrients uptake by water plants in various CWs for treating point source pollution. On the other hand, few studies considered nutrients uptake by water plants in free water surface(FWS) CWs for treating non-point source pollution. METHODS AND RESULTS: To investigate characteristics of nutrient uptake by water plants in FWS CWs, dry weights, nutrients content and nutrients uptake by water plants were investigated from April, 2008 to October, 2008. Dominance plants were Phragmites japonica STEUD (PHRJA), Nymphaea tetragona ANGUSTA(NTMTE), Typha orientalis PRESL(TYHOR), Phragmites communis TRINIUS(PHRCO) and Zizanis latifolia TURCZ(ZIZLA) in FWS CWs. The dry weights of water plants in August were higher in the order of TYHOR(54.27 g/plant) > PHRJA(44.30 g/plant) ${\geqq}$ PHRCO(39.60 g/plant) ${\geqq}$ ZIZLA(37.80 g/plant) ${\fallingdotseq}$ NTMTE(36.75 g/plant). The T-N and T-P contents by water plants were not significantly differences regardless of cultivation period. The maximum amount of T-N uptake by water plants in August were 773 mg/plant for PHRJA, 625 mg/plant for NTMTE, 1206 mg/plant for TYHOR, 754 mg/plant for PHRCO and 768 mg/plant for ZIZLA. The maximum amounts of T-P uptake by PHRJA, NTMTE, TYHOR, PHRCO and ZIZLA were 397, 177, 411, 261 and 229 mg/plant in August, respectively. CONCLUSION(s): The results of this study suggest that optimum water plant was Typha orientalis PRESL in free water surface constructed wetlands.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.281-287
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• 2011

BACKGROUND: According to Korean regulations, bottled waters (BWs) can not be treated with chemical disinfectants like chlorine, so UV and ozone disinfection is applied. During the past several years, chemicals were detected in some BWs, and the public was concerned about the safety of BWs. METHODS AND RESULTS: Mineral waters were stored for 180 days at $25^{\circ}C$ and $50^{\circ}C$, tested acetaldehyde and formaldehyde by HPLC. When mineral waters were put in a PET bottles, the formaldehyde level ranged from 5 to $66{\mu}g/L$ during 180 days at $50^{\circ}C$. While the acetaldehyde level ranged from 31 to $221{\mu}g/L$, it was low than $16{\mu}g/L$ in glass bottle. CONCLUSION(s): This result showed that formaldehyde and acetaldehyde were detected higher in PET bottles than glass bottles, these also increased depending on the time of storage. Concentration of formaldehyde and acetaldehyde could be significantly influenced by the time of storage and temperature.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.322-332
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• 2013

This study was conducted to understand the control mechanism of Sika deer (Cervus nippon taiouanus) populations which are adapted to the natural forest areas and the semi-natural forest areas of Korea. We monitored and analyzed the behaviour patterns and habitat characteristics of Sika deers. After we released 12 Sika deers (male 3, female 9) each at the two study areas in and around Seoul under the approval of Korean government, we monitored them through our survey researchers' naked eyes from May 2011 to January 2012. We discriminated their habitat patterns to 4 major places - eating food place, drinking water place, daytime rest place, and nighttime rest place. Our results showed that Sika deer preferred the open grassland habitats for feeding and resting in daytime but the closed bushland for their protection and sleep. We also found the recommended sex ratio of adult male to female in a herd was 1 : 4~9 for breeding and they had few cubs in a herd. The average amount of food for 1 adult deer was 391.62 kg of fresh grasses and 286.90 kg of hay per year. Our results suggest that the amount of drinking water required for a deer when grazed on grasses during spring and summer seasons is 256.8 L and when a deer feeds on dry food during autumn and winter seasons, 209.8 L of water is required. From these results, we observe that the amount of drinking water was affected substantially by the moisture content of their food. This observational study must be very valuable for land managers to judge the number of deers that should be released in natural areas without high risk and to ascertain the sex ratio of large mammals including Sika deer. Therefore, we conclude that this population control mechanism study consists of efficient basic data and their values must be very effective for various purposes.

• Journal of Animal Science and Technology
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• v.46 no.2
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• pp.193-200
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• 2004

This experiment was carried out to determine energy requirements for maintenance of Hanwoo steers. Nine Hanwoo steers weighing 376.6$\pm$12.5kg were used in this experiment and fed rice straw(44%) and concentrate (56%) at three different energy levels; 0.8 times maintenance(0.8M), 1.2 times(1.2M) and 1.6 times(1.6M), respectively. Dry matter intake was 48.5, 65.9 and 86.5g/$BW^{0.75}$ for 0.8M, 1.2M and 1.6M, respectively. Increase in energy intake with the increased DM intake did not affect digestibilities of dry matter, organic matter, crude protein, crude fiber, crude fat and nitrogen-free extract. Gross energy intake averaged 190.8, 255.8 and 340.9kcal/BW0.75 for 0.8M, 1.2M and 1.6M, respectively. Energy loss was 41% feces and 0.6${\sim}$1.5% urine of gross energy intake. Further, energy loss from methane produced during rumen fermentation was 5${\sim}$9%, while body heat loss averaged 40${\sim}$60%. Intercept of the regression equation between ME intake and retained energy indicated that energy requirement for maintenance was 124.3kcal $ME/BW^{0.75}$.

• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.481-490
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• 2007

An experiment was conducted to investigate the effects of dietary supplementation of MOS, lectin and organic acid mixture(Organic acid F, Organic acid G) on the egg production, egg quality, profile of leukocytes and erythrocytes, small intestinal microflora and immune response in laying hens. A total of 900 Hy-line BrownⓇ laying hens of 48 wks old were assigned to one of the following 6 dietary treatments:control(C), C+AvillamycinⓇ 6ppm, C+MOS 250ppm, C+lectin 12.5ppm, C+Organic acid F(formic acid 35.4%, formate 34.6%, potassium 30.0%) 0.3% and C+0rgarnic acid G(fumaric acid 23%, calcium formate 14%, potassium sorbate 5%, calcium propionate 7%) 0.06%. Each treatment was replicated five times with thirty birds per replicate, housed in 2 bird cages. Feeding trial lasted for 6 wks under 16 hours lighting regimen. All supplemental groups were higher than the control in 6 wks hen-day and hen-housed egg production showing the highest with MOS treatment(P<0.05). Soft & broken egg productions were lower in supplemental groups than in the control except lectin treatment(P<0.05). Eggyolk color of supplemental groups was higher than that of the control except Organic acid G treatment(P<0.05). The values of RBC, HB, MCHC were highest in lectin treatment and lowest in MOS treatment(P<0.05). The numbers of intestinal microflora were not significantly different among the treatments. Serum IgG levels of all supplemental groups were higher than those of the control(P<0.05). In conclusion, for supplementation of antibiotics, immune modulators and organic acid mixture improved production parameters in general. Among the supplements, MOS showed the best performance in egg production and eggyolk color.