• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.300-309
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• 2014

Objectives: The objective of this study is to evaluate microbial exposure hazards in the metal-working fluids(MWF) handling industry. Methods: Air quality parameters(airborne bacteria, fungi, endotoxin and oil mist) and bulk MWF in storage tanks were evaluated at 54 points at nine sites in South Korea. Results: The geometric means(GM) of culturable airborne bacteria, fungi, endotoxin and oil mist concentration were $133CFU/m^3$(n=376, range $7{\sim}6,510CFU/m^3$), $159CFU/m^3$(n=381, range $7{\sim}8,469CFU/m^3$), $8.06EU/m^3$(n=103, range $0.34{\sim}280.4EU/m^3$) and $0.20mg/m^3$(n=104, range $0.01{\sim}2.87mg/m^3$), respectively. The ratio of indoor to outdoor concentration was 2.7 for bacteria, 6.1 for endotoxin, and 4.8 for oil mist. Even though average airborne bacteria concentration did not exceed recommended exposure limits($1,000CFU/m^3$), MWF in the storage tanks was highly contaminated with bacteria(arithmetic mean $2.1{\times}10^6CFU/ml$) and exceeded recommended bacteria limits($10^5CFU/ml$). Conclusions: It is necessary for MWF handling workplaces to conduct periodical biohazard inspection of MWF storage tanks. Additionally, further research may be necessary to establish biological occupational exposure limits.

• Korean Journal of Community Nutrition
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• v.9 no.6
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• pp.742-752
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• 2004

The purpose of this study is to offer information related to recommended dietary allowances for young children and food guidelines for preschool children in Sweden. Sweden, located in Europe, is the most developed country for young child care system. Swedish nutrition policy background, Swedish recommended dietary allowances for young children, and food guidelines of early childhood education center in Sweden were used. The number of Swedish child care centers increased from 70,000 in 1970 to 700,000 in 2000. The Swedish Institute of Public Health promoted children's indoor and outdoor activity. The aim of the Swedish public health contains children's safety, good food habits, and eating food safely. Swedish Food Administration made recommended dietary allowance and food guidelines for children care centers. The aim of food guidelines was to increase energy, calcium, iron, and dietary fiber intake. Swedish RDA contains minimum and maximum intake as well as mean intake for macro and micro nutrients. The fat intake ratio of energy is increased for younger children. For preschool children, the food guideline is determined by dietary allowances for breakfast, lunch, and snack respectively. Food guideline contains meal time schedule, menu for each meal using food model, amount of food for age group, and recommended dietary allowance for each meal. It is recommended for Korean early childhood education center: 1) Korean RDA for young children should be made range of intake, minimum and maximum intake. 2) Food guideline should be make for Korean child care center. 3) Korean child care centers should offer an afternoon snack twice for children who return home late. 4) Nutrition education program for preschool teachers should be developed for children's good eating habits and health promotion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.80-83
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• 2002

The effect of chloride content on the corrosion of reinforced bar in concrete was studied. The mixing ratio of the concrete was 1 : 1.78 : 5.35 : 4.73 (water : content : ballast : sand). The studied chloride content was in the range of 0∼3.5 wt%. The corrosion potentials were measured in every week for two years. The copper-copper sulfate electrode (CSE) was employed as a reference electrode. After two years, the corroded structure was examined and compared to measured corrosion potential. Any visible difference was founded in the specimen located indoor and outdoor. The chloride concentration enhanced rusting and reinforced bar, shifting the potential to active range. The results showed good argument with Van daveer criteria. In 3.5 wt% chloride, the potential shifted belong -350 mV after 58week. Specimen in 1.75 wt% chloride, showed the potential between -200 mV∼-350 mV. However those in free chloride solution maintained above -200 mV for the studied period. It can the concluded that the chloride enhanced corrosion of rebar in concrete and the electrochemical potential can be a promising corrosion monitoring technique.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.372-384
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• 2014

DTV field tests have been performed to measure field strength and to check reception ratio on indoor and outdoor sites. They use an antenna of 9m to measure DTV signal in case of outdoor measurement on the road. Modern skyscrapers require the analysis of vertical-directional wave propagation by measuring vertical-directional DTV signal. Even if the field strength is above the reception threshold of $43dB{\mu}V/m$, the reception is impossible in case of strong multi-path or high impulse noise. So, vertical-directional field measurement is essential in environment of tall buildings. In this paper, we developed an octo type multi-copter to measure vertical-directional DTV signal level. A compact and portable DTV signal level meter, an antenna, a microwave transmitter for data transmission, and a recording equipment are equipped in the multi-copter. Three different sites are selected to test the measurement system. Developed measurement system using the multi-copter is very useful in measuring vertical-directional DTV signal, especially in apartments, non-accessible area by vehicles, and forbidden areas.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.4
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• pp.1-10
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• 2017

This study investigated indoor temperature and humidity control and PM1 and PM10 mitigation effects of a single green wall (Case 1), two green walls (Case 2), and two green walls plus a waterfall (Case 3) in comparison with a control without either a green wall or waterfall. Experiments were conducted in the office of Chungbuk National University from August to September, 2015. Experiments were carried out sequentially in the order of control, Case 1, Case 2, and Case 3. Data collected from August 17 to August 20, 2015 (Experiment 1), and from August 31 to September 3, 2015 (Experiment 2), when outdoor temperature was relatively constant, were analyzed. Plant volume ratios by indoor landscaping of the control, Case 1, Case 2 and Case 3 were 0.0, 0.6, 1.2, and 1.4%, respectively. Compared to the control, average temperatures of Case 1, Case 2 and Case 3 were decreased by 0.3~0.7, 0.7~0.9 and $1.0^{\circ}C$, respectively, and relative humidity was increased by 1.8~8.7, 9.2~14.6 and 14.8~21.9%, respectively. Three hundred minutes after exposure to mosquito repellent incense particles, the ratio of the remaining PM1 of the control, Case 1, Case 2 and Case 3 were 25.0, 22.0%, 21.2%, 17.3%, respectively, in Experiment 1 and 42.3, 28.9, 23.1, and 30.9%, respectively, in Experiment 2. As indoor greening increased the effect of indoor temperature, PM1 and PM10 mitigation were greater, and temperature and humidity were lower. The greater the relative humidity was, the faster PM1 and PM10 mitigation tended to be.

• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.19-26
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• 1995

Ecological studies of Aedes togoi, the vector of malayan filariasis, were ci,wind out at Tolsando, Yosu and Sokcho area in 1991. The adult population of Aedes togoi was continuously appeared from the first week of April to the end of November showing the highest density in .truly. The larvae of Aedes togoi were found at rock pools from March to December in Sokcho area and the density was highest in July and August, whereas in the southern coastal area (Yosu), the larvae were found throughout the year and the density was the highest in Tune. The rate of larvae inhabited below 0.5% salinity was 45.7% in Sokcho and 51.7% in Yosu. The feeding activity of Aedes togoi was nocturnal, with the peak period of 01 :00-03:00 hours. Indoor feeding activities were slightly higher than outdoors showing the biting ratio of 1 :0.8 (indoor: outdoor). The average number of Aedes togoi attracted to CO2 gas was 8.5 whereas 117 Anophelei sinensis was attracted. The result indicates that CO2 is not an effective attractant for host seeking of Aedes togoi compared to Anopheles sineteis. The most common place was bedroom with 54.5% of total collections and next to stock place (18.2%), floor(9.1%) and kitchen (9.1%).

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.76-86
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• 2014

Purpose: The objective of this study was to measure emissions of gases (ammonia ($NH_3$), hydrogen sulfide ($H_2S$) and carbon dioxide ($CO_2$)), volatile organic compounds (VOC) and odor from two shallow pit pig nursery rooms. Gas and odor reduction practices for swine operations based on the literature were also discussed. Methods: This study was conducted for 60 days at a commercial swine nursery facility which consisted of four identical rooms with mechanical ventilations. Two rooms (room 1 (R1) and room 2 (R2)) with different pig numbers and ventilation rates were used in this study. The pig manure from both the R1 and R2 were characterized. Indoor/outdoor temperatures, ventilation rates/duration, $NH_3$, $H_2S$, $CO_2$, and VOC concentrations of the ventilation air were measured periodically (3-5 times/week). Odor concentrations of the ventilations were measured two times on two days. Three different types of gas and odor reduction practices (diet control, chemical method, and biological method) were discussed in this study. Results: The volatile solids to total solids ratio (VS/TS) and crude protein (CP) value of pig manure indicated the pig manure had high potential for gas and odor emissions. The $NH_3$, $H_2S$, $CO_2$ and VOC concentrations were measured in the ranges of 1.0-13.3, 0.1-5.7, 1600-3000 and 0.0-1.83 ppm, respectively. The $NH_3$ concentrations were found significantly higher than $H_2S$ concentrations for both rooms. The odor concentrations were measured in the range of $2853-4432OU_E/m^3$. There was significant difference in odor concentrations between the two rooms which was due to difference in pig numbers and ventilation duration. The literature studies showed that simultaneous use of dietary control and biofiltration practices will be more effective and environmentally friendly for gas and odor reductions from pig barns. Conclusions: The gas and odor concentrations measured in the ventilation air from the pig rooms indicate an acute need for using gas and odor mitigation technologies. Adopting diet control and biofiltration practices simultaneously could be the best option for mitigating gas and odor emissions from pig barns.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.355-362
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• 2019

Cotesia glomerata L., an internal parasitoid wasp, attacks the larvae of both the cabbage white butterfly (Artogeia rapae L.) and the diamondback moth (Plutella xylostella L.). It can be utilized as a natural biological enemy to control these two insect pests in the summer cabbage fields of the Korean highland areas. The developmental response and sex ratio of C. glomerata to various temperatures and its longevity were examined in the laboratory. The egg-to-larva and pupa stages of C. glomerata were 12.1 ± 2.1 and 6.4 ± 1.8 days, respectively, at 20℃, The developmental threshold for egg-to-larva and pupa stages were 7.7 and 8.5℃, respectively. The sex ratios of C. glomerata when reared under various temperatures were 61.0 ± 4.5% at 15℃, 44.2 ± 1.0% at 20℃, and 39.0 ± 2.3% at 25℃, and the incidence of females increased as the temperature decreased. The longevity of C. glomerata when fed a 10% sugar solution was 20.4 ± 0.2 days, while in adults without any feed, the longevity was 3.6 ± 0.1 days. Indoor reared C. glomerata adults were released into cabbage fields from 2007 to 2018, in early August of each year, and the outdoor parasitism rates were surveyed. The parasitism rates were found to increase gradually as the year passed (Y = 0.2696X + 2.8633, R² = 0.3994). The highest parasitism rate was observed in 2013 at 7.6%, and the lowest was in 2018 at 6.5 %. These results could be used as basic information for biological control of kimchi cabbage pests at highland fields.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.293-301
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• 2013

This study was carried out to investigate the pesticide residue pattern among different leafy vegetables applied with foliar spraying under greenhouse and to check extrapolating from some residue trial data to other minor crops. Leafy vegetables used in this study were: Mustard greens (Brassica juncea L.), Kale (Brassica oleracea L.), Dacheongchae (a kind of pak-choi (Brassica rapa subsp. chinensis L.)), Leaf broccoli (Brassica oleracea var alboglabra), Perilla leaf (Perilla frutescens (L.) Britton var. Frutescens), Leaf lettuce (Lactuca sativa L.), Swiss chard (Beta vulgaris L. subsp. vulgaris) and Red leaf chicory (Cichorium intybus L. var. foliosum Hegi). These are cultivated all year under indoor or outdoor and cut the leaf from plant continuously during harvest time. The amounts of pesticide deposit in/on the continuous harvesting leafy vegetables were affected by the ratios of leaf area to weight. Ratio of perilla leaf was the largest among crops as 58 $cm^2/g$. The residue levels of 7 pesticides in/on perilla leaf were the highest than those of other crops through the statistical analysis from zero day to fifth day after last application. The representative crop in 8 crops was perilla leaf selected based on the amounts of daily consumption and the high residues. This study suggest that the continuous harvesting leafy greens should be separated from the one time harvesting leafy vegetables for the pesticide recommendations because of different harvesting habits and pre-harvest intervals.