• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.397-406
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• 2015

The different compliance concentration of effluent limit is applied to effluent discharged from public sewage treatment works(PSTWs) in each watershed on the basis of water quality thereof in accordance with the enforced Watershed Sewer System Maintenance Plan in 2013. It is necessary to set the compliance concentration of effluent limit for PSTWs in watershed sewer system, in order to achieve water quality criteria for regional watersheds or target water quality under TMDL program. Watershed Environmental Agencies establish the Watershed Sewer System Maintenance Plan and set the compliance concentration of effluent limit for PSTWs under the plan. The agencies have a plan to apply strengthened effluent BOD concentration limits for PSTWs in I to IV area grade, respectively. Effluent BOD concentration limits will be strengthened from 5~10 mg/L to 3 mg/L in II~III area grade, from 10 mg/L to 5 mg/L in IV area grade. Uniform application of effluent BOD concentration limits to PSTWs in the watershed sewer system need to be complemented considering type of sewage treatment technology employed and watershed characteristics. Therefore, this study presents assessment methodology which analyze for the compliance concentration of effluent limit to affect water quality of discharge watershed using simulation model for the Jinwee-stream watershed.

• Fibers and Polymers
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• v.6 no.3
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• pp.224-228
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• 2005

This paper focuses on the application of a novel mathematical limit approach derived for K/S values in reactive dyeing of cotton fabrics. The relation obtained from Kubelka-Munk equation is used because the Kubelka-Munk equation is the basic relationship among fabric reflectance, fabric dye content and dyestuff characteristics. The limit approach derived in a former paper is applied to the laboratory dyeings and the dyeing behavior of some reactive dyes on cotton knitted fabric has been obtained. The results of the laboratory experiments are discussed using the new mathematical approach. When the actual K/S values obtained from the dyeings and the calculated K/S values derived by the limit approach are considered independently, it is observed that the limit relation is val id for low dye concentration applications. When the K/S values are calculated taking the K/S value of the initial dyeing concentration $(0.1\;\%\;owf)$ as the starting concentration by applying the result of the derived limit approach, the calculated K/S values fit with the ones obtained in actual dyeings. It is concluded that the novel approach presented in the paper can be used in calculating the K/S values when the initial dyeings at low dye concentrations are carefully carried out.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.109-114
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• 2001

Explosive characteristics of the city gas were determined by using the gas explosion apparatues. The explosive range is determined between lower explosive limit of 5.0% and upper explosive limit of 15.3% at atmosphere and even though the oxygen concentration is decreased, lower explosive limit is not changed, but upper explosive limit is rapidly decreased. The minimum oxygen for combustion is determined 10%. The maximum explosion pressure is determined 5.72$\textrm{cm}^2$ and the maximum rate of explosion pressure rise is oxygen concentration of 12% to determined 160.12$\textrm{cm}^2{\cdot}$sec.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.757-766
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• 2012

In this study, we have examined concentration distribution and patterns of PCBs in waters, sediments and soils in an agricultural area of South Korea to investigate the relationship between PCBs sources and concentration levels. The concentration of PCBs in water samples were ranged from lower values below detection limit to 8.25 ug/L and the concentration of PCBs in sediment samples were ranged from lower values below detection limit to 76.67 ug/Kg. The concentration of PCBs in soil samples were ranged from lower values below detection limit to 23.51 ug/Kg. These contamination levels were far below the guideline values suggested for environmental quality assessment. The homologue patterns in samples varied from sample to sample, but isomer patterns were very similar with each other. PCB-138 and PCB-153 were predominant congeners in the soil and sediment, which were similar to the results obtained from previous studies. With these results, the assessment of potential sources of PCBs contamination in the sediments of the Nakdong river basin was performed. The principal components were extracted by Principal Component Analysis(PCA). As the result of PCA, it could be expected that PCBs in samples of this study were more affected by PCB products than combustion processes and mostly affected by already-known sources. The PCBs in the soil and sediment samples were related with commercial PCB products.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.493-502
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• 2015

In accordance with the Watershed Sewer System Maintenance Plan enforced on February 2, 2013, the different compliance concentration of effluent limit be applied to effluent discharged from public sewage treatment works(PSTWs) in each watershed on the basis of water quality thereof. With the introduction of watershed sewer system, it is necessary to set the compliance concentration of effluent limit for PSTWs situated in the watershed, by region and PSTW size, to achieve water quality criteria for regional watersheds or target water quality under TMDL program. Watershed Environmental Agencies establish the Watershed Sewer System Maintenance Plan and set the compliance concentrations of effluent limit for PSTWs under the plan. The agencies plan to apply tougher effluent BOD concentration limits in Class I to IV areas. Effluent BOD concentration limits will be toughened from 5~10 mg/L to 3 mg/L in class II~III areas, from 10mg/L to 5mg/L in class IV areas. Uniform application of effluent BOD concentration limits to PSTWs in the watershed sewer system need to be complemented considering type of sewage treatment technology employed and watershed characteristics. Therefore, this study presents method to determine the compliance concentration of effluent limit from PSTWs in the watershed.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.101-104
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• 2016

Background: To protect the public from natural radioactive materials, the 'Act on safety control of radioactive rays around living environment" was established in Korea. There is an annual effective dose limit of 1 mSv for products, but the activity concentration limit for products is not established yet. Materials and Methods: To suggest the activity concentration limits for consumer goods containing NORM, in this research, we assumed the "small room model" surrounding the ICRP reference phantom to simulate the consumer goods in contact with the human bodies. Using the Monte Carlo code MCNPX, we evaluate the effective dose rate for the ICRP reference phantom in a small room with dimension of phantom size and derived the activity concentration limit for consumer goods. Results and Discussion: The consumer goods have about 1600, 1200 and $19000Bq{\cdot}kg^{-1}$ for $^{226}Ra$, $^{232}Th$ and $^{40}K$, and the activity concentration limits are about six times comparing with the values of building materials. We applied the index to real samples, though we did not consider radioactivity of $^{40}K$, indexes of the some samples are more than 6. However, this index concept using small room model is very conservative, for the consumer goods over than index 6, it is necessary to reevaluate the absorbed dose considering real usage scenario and material characteristics. Conclusion: In this research, we derived activity concentration limits for consumer goods in contact with bodies and the results can be used as preliminary screening tool for consumer goods as index concept.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.64-72
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• 1976

This experimental work was carried out to investigate the fatigue bending strength on various shapes and sizes of notches of the domestically manufactured steel plate. The notch types tested were a circular hole, U-and V-notches. The S-N diagram for different notch shapes were discussed in relation to plan bending strength and stress concentration factor of notches .The results of the experiments are summarized as follows : (1) The difference between stress concentration factor and notch factor was greater as the radium of notch root became smaller, and these values approached to an identical value as the radium of notch root increased. (2) It was shown that the plane bending fatigue limit of bar without notch for the hotrolled steel having the tensile strength of 33.1kg/$mm^2$was 17.0kg/$mm^2$. (3) U-and V-notch had a greater effect of stress concentration factor on the endurance limit, but O-hole showed the same effect only for $\o\pm2mm$. (4) For the same radius of notch root, U-notch showed a lower value of fatigue limit compared to V-notch and O-hole.

• Journal of Environmental Science International
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• v.27 no.7
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• pp.587-595
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• 2018

This research investigated the characteristics of NO and $NO_2$ concentration at roadside (Choryangdong) and residential (Sujeongdong) locations in Busan. The NO concentration at roadside and residential were 34.7 and 8.0 ppb, respectively, and $NO_2$ at roadside and residential were 31.6 and $18.0ppb\;{\mu}g/m^3$, respectively. The NO concentration was the highest in winter at roadside at 37.1 ppb, followed by 35.0 ppb and 34.0 ppb in summer and fall, respectively. $NO_2$ concentration was the highest in spring at roadside at 39.6 ppb, followed by 30.4 ppb and 28.3 ppb in fall and winter, respectively. Number of exceedances per year of 1 hr limit value (0.10 ppm) for $NO_2$ at roadside and residential were 3,585 and 3 hours, respectively. Number of exceedances per year of 24 hr limit value (0.06 ppm) for $NO_2$ at roadside and residential were 32 and 1 days, respectively. Number of exceedances per year of 1 hr limit value (0.1 ppm) for $O_3$ at roadside and residential were 1 and 14 days, respectively. These results indicated that understanding the relationship between roadside and residential could provide insight into establishing a strategy to control urban air quality.

• Journal of Radiation Industry
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• v.10 no.1
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• pp.37-41
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• 2016

The recent prevalence of PET examinations in Korea has led to an increase in the number of cyclotrons. The medical isotope $^{18}F$ produced in most cyclotron facilities currently operating in Korea is emitted into the environment during the production of [$^{18}F$]FDG, a cancerdiagnosis reagent. The amount of [$^{18}F$]FDG synthesized determines the radioactive concentration of $^{18}F$ in the exhaust. At some facilities, this amount temporarily exceeds the emission limit. In this study, we evaluated the $^{18}F$ radioactivity concentration in the exhaust from the cyclotron facility at Chosun University. The $^{18}F$ radioactivity concentration was measured using an air sampler and a HPGe semiconductor detector. The measurements showed that the radioactive concentration of $^{18}F$ in the exhaust at the cyclotron facility at Chosun University was the highest during [$^{18}F$]FDG synthesis but remained under the legal limit of $2,000Bq\;m^{-3}$.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.107-113
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• 2011

This study was performed for the application of the exposure limit in work field and the relative noxious gas concentration was estimated by using a miniature ship. The noxious gas concentration about light and shade number distribution of measuring subject field was estimated by using floating visualization image from a miniature ship in a large wind tunnel. About the concentration estimation, the correlation of concentration distribution drawn from the existing experimental results was used, the estimation result satisfied LTEL standard.