• 한국유체기계학회 논문집
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• 제6권2호
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• pp.15-22
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• 2003

Comprehensive study on a centrifugal blower for air-purifier involving a few physical filters for percolation process has been accomplished for an optimal design of the air handling system. The filtering media causes a flow resistance for induced flows by a rotating impeller. The present methodology is to adopt PIV system for velocity measurements and wind tunnel connected with an anechoic chamber for total performance test of the blower. Trial prototypes for the blades of a rotor and casing are presented for satisfaction of both flow rate and noise level set by design objectives. Tapered blades with a special casing for a fan show good performance data. The results of velocity fields also explain the reason of improvements of the blower performance.

• 한국대기환경학회지
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• 제27권1호
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• pp.63-72
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• 2011

This study describes the impact of positive sampling artifact caused by a filter-based sampling in the determination of ambient organic carbon (OC). Three different sampling media combinations were employed for this investigation: (1) Quartz filter-alone (Q-alone), (2) quartz filter behind quartz-fiber filter (QBQ), and (3) quartz filter and quartz filter behind Teflon filter (Q-QBT). The measurement of ambient OC was carried out at a semi-urban site near oceanside at the end of November of 2008. It was found that Q-alone sampling configuration resulted in a higher OC than QBQ and Q-QBT by 14% and 28%, respectively due to no correction for positive artifact caused by adsorption of gas-phase OC onto the filter. A lower quantity of OC was collected from the backup quartz filter on QBQ than that from Q-QBT. A possible explanation is that the front quartz filter of QBQ was not fully saturated with gas-phase OC during the sampling period, allowing smaller amount of gas-phase OC to reach the backup quartz filter. The contribution of positive artifact to $PM_{2.5}$ mass was approximately 2.15 ${\mu}g/m^3$ which is equivalent to 6% in terms of Q-QBT sampling configuration. The positive artifact was found to be more dominated during summer than during winter, showing temperature dependence. It was concluded that Q-QBT sampling configuration offers less impact of positive artifact on ambient OC sampling than QBQ in quantification of OC.

• 한국인터넷방송통신학회논문지
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• 제21권1호
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• pp.121-129
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• 2021

최근 중국에서 발생하는 황사와 더불어 국내에서는 뉴스 등 미디어를 통해 미세먼지가 큰 화제가 되고 있다. 외부에서 발생하는 미세먼지도 있지만, 외부 미세먼지가 내부로 유입되면서 공기 청정기 제품의 구입율이 높아지고 있다. 공기 청정기는 내부에 필터를 사용하고 있으며, 센서를 통해 필터의 교체 유무를 LED 알람을 통해 사용자에게 알려준다. 하지만, 현재 필터율이 얼마나 감소하였는지 측정하고, 작동하는 송풍기의 압력을 결정해주는 제품은 없는 상태이다. 따라서 본 논문에서는 IoT 기기인 아두이노와 미세먼지 센서, 차압 센서를 활용하여 데이터를 직접 생성하고, 측정된 미세먼지와 압력 값을 계산하여 필터율에 따라 필터가 얼마나 노화되었는지 확인할 수 있는 프로그램을 파이썬 프로그래밍을 이용하여 개발하였다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 추계학술대회 논문집
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• pp.154-155
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• 2008

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 춘계학술대회 논문집
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• pp.642-644
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• 2008

• 한국물환경학회지
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• 제31권5호
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• pp.523-532
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• 2015

Hydrocyclone is widely used in industry, for its simple design, high capacity, low maintenance and low operational cost. The objective of this study is to develop hydrocyclone coagulation and filtration system. The system is made of hydrocyclone ballasted coagulation with polyaluminium chloride silicate (PACS) and upflow filter to treat micro particles in urban storm runoff. Roadside sediment particles (< $200{\mu}m$) was mixed with tap water to make various turbid suspensions to simulate urban storm runoff. The filter cartridge was filled with polyethylene media system and ran 1hr per everyday and total operation time were 8.19hrs and backwashing everyday after end of operation. The operation condition of flowrate was $8.2{\sim}11.9m^3/day$ (mean $10.1m^3/day$) and surface overflow rate (SOR) based on filter surface area was $45.5{\sim}65.9m^3/m^2/day$ (mean $55.7m^3/m^2/day$). The range of PACS dosage concentration was 14.0~31.5 mg/L. As the results of operation, the range of removal efficiency of turbidity, SS were 81.0~95.8% (mean 89.5%) 81.8~99.0% (mean 91.4%), respectively. An increase of filtration basin retention time brought on increased of removal efficiency of turbidity and SS, and increase of SOR brought on decreased of removal efficiency. During the first flush in urban area, storm runoff have an high concentration of SS (200~600 mg/L) and the filtration bed becomes clogged and decreased of removal efficiency. Backwashing begins when the drainage pipe valve at the filtration tank bottom is completely open (backwashing stage 1). Backwashing stage 2 was using air bubbles and water jet washing the media for 5 mins and open the drainage valve. After backwashing stage 1, 2, 61.83~64.04%, 18.53~27.51% of SS loading was discharged from filtration tank, respectively. Discharged SS loading from effluent was 7.12~14.79% and the range of residual SS loading in fliter was 2.26~5.00%. The backwashing effects for turbidity, SS were 89.5%, 91.4%, respectively. The hydrocyclone coagulation and filtration with backwashing system, which came out to solve the problems of the costly exchange filter media, and low efficiency of removing micro particles of filter type nonpoint treatment devices, is considered as an alternative system.

• 한국융합학회논문지
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• 제10권4호
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• pp.147-151
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• 2019

현대인들은 가정, 학교 혹은 직장, 병원, 쇼핑몰, 지하철역과 객실, 주차장 등 일상생활의 대부분을 실내에서 보내게 된다. 이렇듯 실내에 갇힌 현대인들은 갇힌 공기 속에서 살아갈 수밖에 없다. 이에 실내 공기질 향상을 위한 공기정화장치는 많이 개발되었으나 대다수의 공기정화장치는 필터에 의한 필터링과 유해세균 살균방식에 있어 자외선이라는 제한된 영역에서의 살균방식에 국한 할 수밖에 없었다. 여기서는 실내 공기질 향상은 물론 원천적으로 실내공기중의 부유 세균을 제거하고, 자외선뿐만 아니라 가시광선에서도 활동하는 광촉매를 적용한 미디어광촉매필터를 활용한 광대역대 활성광촉매를 활용한 융 복합 구조 공기살균정화장치 개발하고자 한다.

• 센서학회지
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• 제27권3호
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• pp.143-149
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• 2018

In this paper, we introduce an edge-spike modulation method for visible light communication (VLC). This method is effective in preventing LED flicker and 120 Hz noise interference in base-band VLC. In the VLC transmitter, edge-spikes are generated by passing the digital data through a simple RC-high pass filter (HPF). The LED modulation of the edge-spikes does not change the average power of the LED light; thus it prevents LED flicker. In the VLC receiver, the 120 Hz noise from other lighting lamps is easily eliminated by RC-HPF, while the edge-spike signal is detected normally. In our experiment, the message of an air-quality sensor was successfully transmitted using edge-spike modulation. This structure is useful in constructing, e.g., wireless gas monitoring sensor systems to warn and prevent harmful gas leakage accidents in buildings using LED light.

• 한국물환경학회지
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• 제20권6호
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• pp.664-669
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• 2004

An upflow BAF(Biological Aerated Filter) equipped with an expanded clay media was applied to reuse weaving wastewater of water jet loom. The performance of lab-scale biofilter was investigated by the adjustment of EBCTs(Empty Bed Contact Time) and the packing ratio of media, which were changed 1.1 to 3.7hr and 38 to 63%, respectively. In most conditions except 1.1hr of EBCT, BOD, CODcr, SS and Turbidity of the effluent were 1~4mg/L, 7~16mg/L, 1~5mg/L and 5~14NTU, where their removal efficiencies were 76~95%, 82~93%, 63~94% and 59~81%, respectively. From the observation of SEM(Scanning Electron Microscope) photographs of porous clay media, it was revealed that this media provided good performance of retaining microbes effectively. In addition, $0.44~0.49kgVSS/kgBOD_{rem}$. of low sludge reduction was expected. The most efficient back washing cycle and procedure were once per 4 to 9 days and air including collapse-pulsing method, respectively. Therefore, this system can be of use as an weaving wastewater treatment for reuse.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.343-346
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• 2000

본 BAF 반응기 연구에서의 C/N비의 증가는 산소의 친화도가 큰 호기성 종속영양 미생물에게 유리한 조건을 형성하여 질산화의 효율을 감소시켰으나 공기양의 증가로 인해 질산화 미생물의 활성도는 다시 증가하였다. 총 질소의 제거율은 동일한 C/N비에서 공기량을 증가하여 많은 양의 암모니아성 질소가 질산성 질소로 산화될 때 증가하였으며 이 결과는 무산소조에서 많은 다공성의 여재에 미생물이 두꺼운 생물막을 형성하여 생물막 안쪽으로 용존산소가 쉽게 전달되지 않아 탈질에 큰 영향을 미치지 않은 결과라고 볼 수 있다.