• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.38-45
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• 2023

In this study, the removal efficiency of road sweeping and sand filter facility for removing total suspended solid (TSS) as nonpoint source pollution from expressway was evaluated for the last 10 years (2012~2021) using ROADMOD. ROADMOD is a screening level model and was calibrated for runoff rate and TSS loading both at the inlet, which is the loading from the drainage area, and the outlet, from the sand filter facility. The drainage area is 715 m² and the dimensions of sand filter facility are 1.5 m (wide) × 3.8 m (length) × 1.5 m (depth). The monitoring period for model calibration was the rainfall event during Aug. 31~Sep. 1, 2021 and the amount of rainfall was 74.5 mm. As a result of calibration, the determination coefficients (R²) of the flow rate were 0.66 and 0.86, for the inlet and outlet, respectively, and those of TSS loading were 0.50 and 0.84, for the inlet and outlet, respectively. Considering that ROADMOD is a screening level model, the calibration results were reasonable to evaluate the best management practices (BMPs) on the expressway. Using ROADMOD simulation results for 2012~2021, the average yearly runoff rate from the expressway was 82% and removal efficiency was 9% for road sweeping, 35% for sand filter facility, and 39% for both road sweeping and sand filter facility.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.6
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• pp.440-448
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• 2009

Facility power-line electromagnetic interference (EMI) filters are used to provide radio frequency(RF) isolation between dedicated power distribution services and noise sensitive local power distribution systems. This type of EMI filters generally needs a high current capacity and, in some special applications, a high insertion loss of a minimum 100dB from 14kHz through 10GHz per MIL-STD 220 is required. This paper deals with an analysis and design of a wideband facility power-line EMI filter with the above requirements. The characteristics of the inductor and capacitor at high frequencies are investigated. The characteristics and design method of the facility EMI filter with a high order LC network are also presented. The prototype filter is finally implemented and its performance is verified from the experimental results.

• Journal of Radiation Industry
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• v.11 no.1
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• pp.13-18
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• 2017

Recently, the number of PET cyclotrons has increased in Korea. A cyclotron mainly produces $^{18}F$, which is used for the production of [$^{18}F$]FDG, a cancer diagnostic radiopharmaceutical. For radiation protection, the discharge control standard under the Nuclear Safety Act limits the radioactive concentration of $^{18}F$ in the exhaust discharged from a nuclear power utilization facility to below $2,000Bq\;m^{-3}$. However, the radioactive concentration of $^{18}F$ discharged during [$^{18}F$]FDG production at the cyclotron facility at Chosun University is maintained at about $1,500Bq\;m^{-3}$ on average, which is 75% of the concentration limit of the discharge control standard, and temporarily exceeds the standard as per the real-time monitoring results. This study evaluated the performance of the exhaust filter unit of the cyclotron facility at Chosun University by assessing the concentration of $^{18}F$ in the exhaust, and an experiment was conducted on the discharge reduction, where $^{18}F$ is discharged without reacting with the FDG precursors during [$^{18}F$]FDG synthesis and is immediately captured by the [$^{18}F$]FDG automatic synthesis unit. Based on the performance evaluation results of the exhaust filter at the cyclotron facility of Chosun University, the measured capture efficiency before and after the filter was found to be 92%. Furthermore, the results of the discharge reduction experiment, where the exhaust $^{18}F$ was immediately captured by the [$^{18}F$]FDG synthesizer, showed a very satisfactory 94.3% reduction in the concentration of discharge compared to the existing discharge concentration.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.456-461
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• 2006

The facility of constructed wet land combined with filter media was examined in order to improve the water quality of a polluted stream, which has been performed as a part of national projects. Throughout 2 years of operation for a stream, it can provide the design and operating parameters for the purpose of future construction. The influent flow rate was about 50% against the design capacity. The removal efficiencies of BOD, $COD_{Mn}$, SS, T-N and T-P were 62.9%, 47.1%, 74.8%, 22.4% and 33.5%, respectively. In order to keep this facility stable, the removal of surface filter media and supplement should be periodically conducted. In addition, the proper selection of sites is recommended not to be flooded.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.4
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• pp.194-200
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• 2013

In this study, an exhaust filter unit for removing bad smells is designed and manufactured to understand the characteristics, damages, and effects on humans and animals of bad smell substances in laboratory animal breeding facilities. Using the exhaust filter unit, a deodorization performance test using ammonia gas, as a typical bad smell in an animal breeding room, was carried out for three types of activated and impregnated charcoal filters. The experimental results showed that the pressure loss of the HEPA and carbon filter was increased with flow rate and that the average deodorization performance for the case where an impregnated carbon filter was installed was a maximum value of between 93 and 96%, with various fractional flow rates ranging from 1,500 to $3,500m^3/h$ in a laboratory animal breeding room. The experimental results will also be used for the design and manufacture of a practical and efficient exhaust filter unit to cope with bad smell problems in animal breeding facilities.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.9-16
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• 2009

Further treatment facility using various filter materials was evaluated to treat effluent of constructed wetland. Further treatment facility was installed with 1m length in outlet of 3 constructed wetland (unplanted constructed; reed bed constructed wetland; cattail bed constructed wetland) using 3 filter materials (slag, activated carbon, oyster shell). Flow rate of three further treatment facility was 63 $m^3$/day (slag), 19 $m^3$/day (activated carbon), and 81 $m^3$/day (Oyster shell). COD removal rate of slag, activated carbon, and oyster shell was 6 %, 24 %, 1 %, and removal mass was 32 g/day, 30 g/day, and 5 g/day, respectively. All of further treatment facility was effective to removal organic materials. T-N and T-P removal rate of activated carbon was 24 % and 4 %, and slag and oyster shell was not effective to remove T-N and T-P. Overall, further treatment facility was effective to remove organic mater, constructed wetland combined with further treatment facility can remove nutrient and organic matters effectively.

• Journal of Environmental Impact Assessment
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• v.20 no.6
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• pp.857-866
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• 2011

This research categorized EIA target highways into following three types in order to minimize non-point source pollution from highway runoff. 1. Big drainage basin. 2. Small drainage basin. 3. Bridge section. The Natural, Filter and Swirl-Type devices were evaluated in terms of removal efficiency of TSS, BOD, COD, T-N, T-P, compatibility of site selection, economic feasibility, and maintenance convenience through which the final BMP was selected. According to the removal efficiency result, the area of Big and Small Drainage basin and bridge section had higher removal efficiency with natural facility than that of the Filter or Swirl-Type device. To make appropriate selection of highways'BMP for non-point source pollution, this study will aim to contribute to building more environmentally friendly highways by proposing the selection process that is made of 5 stages. 1. Selecting the target drainage basin. 2. Selecting the land for the mitigation facility. 3. Analysing the ease of maintenance. 4. Technically evaluating each installation. 5. Evaluating the effective implementation methods.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.79-90
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• 2016

The second-stage near surface disposal facility for low and very low level radioactive waste's permanent disposal is to be built. During the institutional control period, the inadvertent intrusion of the general public is limited. But after the institutional control period, the access to the general public is not restricted. Therefore human who has purpose of residence and resource exploration can intrude the disposal facility. In this case, radioactive effects to the intruder should be limited within regulatory dose limits. This study conducted the safety assessment of human intrusion on the second-stage surface disposal facility through drilling and post drilling scenario. Results of drilling and post drilling scenario were satisfied with regulatory dose limits. The result showed that post-drilling scenario was more significant than drilling scenario. According to the human intrusion time and behavior after the closure of the facility, dominant radionuclide contributing to the intruder was different. Sensitivity analyses on the parameters about the human behavior were also satisfied with regulatory dose limits. Especially, manual redistribution factor was the most sensitive parameter on exposure dose. A loading plan of spent filter waste and dry active waste was more effective than a loading plan of spent filter waste and other wastes for the radiological point of view. These results can be expected to provide both robustness and defense in depth for the development of safety case further.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.443.1-443
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• 2002

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.380-383
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• 2007

In this research, we present color filter which is patterned by screen printing method. Analysis of screen printing process, screen printing system, experiment for uniform printing in large area, characteristics of screen printed CF are investigated .In spite of limitation of precision, screen printed color filter is very cost- effective in respect of manufacturing facility and ink usage.