• International Journal of Air-Conditioning and Refrigeration
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• 제13권2호
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• pp.89-98
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• 2005

In this study, indoor VOCs concentration emitted from floor and furniture was measured after the installation of floor and furniture in a real residence. With the measured data, prediction method and predication equations for indoor concentration of each VOCs and BTEX were developed. The following conclusions were drawn from this study. First, according to the predicted results of concentration decrease of BTEX (benzene, toluene, ethylbenzene, m,p,o-xylene) after the installation of floor in a real residence, prediction equation can be expressed using exponential function. Second, in case of floor, more reliable prediction equation can be obtained by using cumulative value of indoor concentration than by using just hourly measured value directly. Indoor concentration of benzene can be expressed as $y=408.52(1­e^{-00031{\times}time})$ with $R^2$ of 0.94 which is significantly high value. Third, toluene showed the highest concentration in case of furniture installation indoors, and it needed the longest time for concentration decrease. However, other substances except toluene showed constant concentration throughout the measurement period. Fourth, in case of furniture installation indoors, prediction equation of toluene concentration decrease is estimated to be $y= 3616.3{\times}e^{(-0.1091{\times}time)}+513.96{\times}e^{(-0.0006{\times}time)}\;with\; R^2$ of 0.95 which is significantly high value.

• 한국환경과학회지
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• 제19권7호
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• pp.819-827
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• 2010

This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.

• KIEAE Journal
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• 제12권6호
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• pp.93-98
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• 2012

The concerns on high ozone concentration phenomenon is significantly growing in Seoul metropolitan area including the industry complex area, like Shiwha Banwol area. The aims of this research is the analysis of relationship between high concentrations of $O_3$ and solar radiation parameters in atmosphere. The understanding of the effects of solar radiation intensity, humidity, high air temperature on ozone concentration in a day is very useful to provide a direction for reducing of the high ozone concentration to a local government or a metropolitan government. The correlation analysis between maximum ozone concentration and various meteorological parameters in 2009 - 2011 carried out using IBM's SPSS program. The results showed that the mean correlations coefficient (R) between daily Ozone maximum and solar radiation resulted R = 0.64 during 2011. May - September in 10 air pollution stations. In case of correlations between daily ozone maximum and relative humidity showed negative correlation R = -0.61. The correlation analysis with mean air temperature during 1-3 PM resulted R = 0.29. This low correlation coefficient could be corrected by using of categorized data of ozone concentration. The daily maximum ozone concentration is more dependent on peak solar radiation and high air temperature during 1-3 PM than its simple daily maximum values. The results of this research would be used to develop the high ozone alert system around Seoul metropolitan area. This correlation analysis could be partially integrated to prediction of ozone peak concentration in connection with other methods like classification and regression tree(CART).

• 한국환경과학회지
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• 제11권7호
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• pp.757-763
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• 2002

The objective of this study is to delineate removal efficiency of the Linear alkylbenzene sulfonates(LAS) in solution by $TiO_2$ photocatalytic oxidation as a function of the following different experimental conditions : initial concentration of LAS, $TiO_2$ concentration, UV wavelength and pH of the solution. It was increased with decreasing initial concentration of LAS and with decreasing pH of the solution. Removal efficiency increased with increasing $TiO_2$ concentration but was almost the same at $TiO_2$ concentration of 2 g/L and 3 g/L, i.e., for initial LAS concentration of 50 mg/L. It was removal efficiency was 85% at 150 min in the case of $TiO_2$ concentration of 0.5 g/L but 100% after 150 min in the case of $TiO_2$ concentration of 1 g/L, 100% after 110 min in the case of $TiO_2$ concentration of 2 g/L and 3 g/L. UV wavelength affection on the removal efficiency of LAS decreased in the order of 254, 312 and 365 nm as increasing wavelength. But the removal efficiency of LAS was nearly the same at UV wavelength of 254 nm and 312 nm.

• 복식문화연구
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• 제31권2호
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• pp.248-261
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• 2023

The conditions for minimizing dyes and additives when dyeing cellulose fibers such as linen, ramie, and hemp fabrics were obtained using glucose, an organic reducing agent. Dyeability and colorfastness were measured through repeated dyeing. The overall surface dyeing concentration followed the linen>hemp>ramie order, and most of the colors were in the range of PB (PurpleBlue). As the glucose concentration increased, the blue series was strengthened, and the color was dark and clear. It was determined that glucose the concentration of 4g/L was appropriate for minimizing the amount of dye. When the dyeing temperature was 30℃, the surface dyeing concentration was the highest, and the color was dark and clear. Although the dyeing concentration increased as NaOH concentration increased, 3g/L (pH 12.37) was considered appropriate for the minimum NaOH concentration, which becomes gradual after the dyeing concentration increased rapidly. It was found that the surface dyeing concentration, when repeated six times for 5 min, was better than that of dyeing once for 30 min. Washing, rubbing, and perspiration colorfastness were all found to be excellent in grades 4-4-5, and colorfastness to light was excellent in grades 5 of linen and hemp and grade 4 of ramie.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2757-2772
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• 2023

The fluid retention effect of the Volume Control Tank (VCT) leads to a long time delay in Reactor Coolant System (RCS) concentration during the boration process. A coupled model combining a lumped-parameter sub-model and a computational fluid dynamics sub-model is currently used to investigate the concentration dynamic characteristic of RCS during the boration process. This model is validated by comparison with experimental data, and the predicted results show excellent agreement with experimental data. We provide detailed fields in VCT and concentration variations of RCS to study the interaction between mixing in VCT and the transient responses of RCS. Moreover, the impacts of the inlet flow rate, inlet nozzle diameter, original concentration, and replenishing temperature of VCT on the RCS concentration characteristic are studied. The inlet flow rate and nozzle diameter of VCT remarkably affect the RCS concentration characteristic. Too-large or too-small inlet flow rates and nozzle diameters will lead to unacceptable long delays. In this work, the optimal inlet flow rate and nozzle diameter of VCT are 5 m³/h and 58.8 mm, respectively. Besides, the impacts of the original concentration and replenishing temperature of VCT are negligible under normal operating conditions.

• 웰빙융합연구
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• 제6권2호
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• pp.1-7
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• 2023

Purpose: The purpose of this study is to investigate the characteristics of airborne radon concentration by season in public-use facilities in South Korea. Research design, data and methodology: The data is provided by the public data portal, and public-use facilities nationwide where radon in the air is measured are specialized sanatorium for senior citizens, libraries, childcare facilities, postpartum care centers, medical institutions, funeral halls, underground shopping malls, and underground subway stations. Results: The facility with the highest radon concentration in public-use facilities was childcare facilities with an average of 50.2 ± 21.7 Bq/m³, while the average of medical institutions was the lowest at 24.8 ± 5.7 Bq/m³. The season with the largest difference in average radon concentration between childcare facilities and medical institutions was in the order of fall (28.6 Bq/m³), followed by winter (28.1 Bq/m³), spring (23.0 Bq/m³), and summer (22.0 Bq/m³). Conclusions: The main concentration levels of each public-use facility shown in this study are all below domestic and international standards, but there is a significant concentration difference between facilities. By season, winter showed the highest average concentration (40.6 ± 21.3 Bq/m³) and summer showed the lowest average concentration (23.8 ± 14.0 Bq/m³).

• 동의생리병리학회지
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• 제16권1호
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• pp.78-88
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• 2002

Experimental animals were divided into 5 groups; normal, cadmium control, and 3 experimental groups. Cadmium control and experimental groups were exposed to 1 mg/㎥ of cadmium aerosol in air by inhalation exposure for 6 hours/day, 5 days/week during 4 weeks. Dosages of 20, 40, and 80mg/kg of extracts of persimmon leaves were intraperitoneally injected to experimental groups respectively and several toxicological parameters and induction of metallothionein were measured from the rats that inhaled cadmium aerosol in air. The results of this study were as follows. Cadmium concentration that cadmium control and experimental groups were inhaled was 0.980±0.061 mg/㎥. Mass median diameter of cadmium aerosol for inhalation exposure was 4.93±0.483㎛. Cadmium content of normal group in lung was 0.088㎍/g and the highest cadmium content in lung, 55.492㎍/g was from 80mg/kg dose group. Cadmium concentration of normal group in blood was 0.348㎍/100㎖ and the highest cadmium concentration in blood, 2.642㎍/100㎖ was from cadmium control. Cadmium concentration of normal group in liver was 0.010㎍/g and the highest cadmium concentration in liver, 31.100㎍/g was from 20mg/kg dose group. Cadmium concentration of normal group in kidney was 0.030㎍/g and the highest cadmium concentration in kidney, 2.526㎍/g was from cadmium control. Cadmium concentration of normal group in intestine was O.064㎍/g and the highest cadmium concentration in intestine, 0.300㎍/g was from 80mg/kg dose group. The highest cadmium concentration in urine by week was 6.080㎍/day from 20mg/kg dose group in the fouth week and the highest cadmium concentration in feces by week was 341.731㎍/day from 20mg/kg dose group in the fouth week. Metallothionein concentration of normal group in lung was 5.769㎍/g and the highest in lung, 30.986㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in liver was 38.856㎍/g and the highest in liver, 169.378㎍/g was from 40mg/kg dose group. Metallothionein concentration of normal group in kidney was 22.228㎍/g and the highest in kidney, 47.898㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in intestine was 2.170㎍/g and the highest in intestine, 13.642㎍/g was from 80mg dose group.

• 상하수도학회지
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• 제28권3호
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• pp.325-337
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• 2014

The research on the actual condition of indoor asbestos concentration in Korea has not been thoroughly accomplished up to now. In this research the ratio of asbestos-containing buildings and indoor asbestos concentration was studied. This investigation was conducted in 2012 and 2013 and buildings were categorized based on region, building type by use, existing space(ground or basement), and construction year, respectively. Also the indoor asbestos concentration change was monitored to evaluation the efficiencies of two types of asbestos-concentration abatement devices. As a result, the ratio of asbestos-containing buildings in Seoul was largely decreased. The ratio of asbestos-containing buildings was higher in hospitals and schools regionally and in ground buildings than in basement. The average indoor asbestos concentrations were 0.0011, 0.0008 piece/cc in 2012 and 2013 investigation, respectively. Those values were much lower than standards(0.01 piece/cc), therefore the threat of indoor asbestos concentration might be negligible. In asbestos-concentration abatement experiments, the circulation velocity of ventilator were changed 2-6.7 m/sec. With 6.7 m/sec of velocity of ventilator, the concentration of indoor asbestos was fluctuated and maximum value was 2.4 piece/cc. With 4.5 and 2 m/sec of velocities of ventilator, the maximum concentration of indoor asbestos was fluctuated and maximum value was 0.9 piece/cc. This indicated that the concentration of indoor asbestos was decreased partly due to the free drop of asbestos. From these results, the proper velocity of ventilator seems to be between 4.7 and 6.5m/sec under this circumstance and further research is required. These research results may be used to guideline of asbestos management policy.

• 대한기계학회논문집B
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• 제38권1호
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• pp.17-24
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• 2014

본 연구에서는 교외지역 대기 에어로졸의 특성을 파악하기 위하여 지구온난화와 밀접한 관련이 있다고 알려진 블랙카본 농도를 측정하였고, 그 결과들을 기상 요소들과 비교하였다. 필터 기반 측정 장치인 MAAP (Multi Angle Absorption Photometer)를 이용하여 측정된 블랙카본 농도와 황사농도, 습도, 온도 및 풍속을 비교하였다. 블랙카본 농도는 4~5월에 높으며 6~9월에 낮은 경향을 보였다. 블랙카본 농도는 PM10(직경 $10{\mu}m$ 이하 입자상 물질) 농도 및 습도와는 비례관계를 보였으며 온도 및 풍속과는 반비례 관계를 보였다. 또한 디젤엔진에서 발생한 블랙카본의 직경 및 광흡수 계수 및 수농도를 측정하여 흡수 단면적을 도출 하였고 이를 통하여 교외 지역 블랙카본의 수준을 평가 할 수 있는 방법을 소개하였다.