• Korean Membrane Journal
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• 제10권1호
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• pp.26-32
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• 2008

The Gongji stream water of Chuncheon city was filtrated by 2 kinds of tubular alumina ceramic MF membranes with periodic $N_2$-back-flushing. $N_2$-back-flushing time (BT) was changed in $0{\sim}50$ sec at fixed filtration time (FT), or back-flushing period, of 4 min for NCMT-5231 membrane ($0.05\;{\mu}m$). Then, FT was changed in $0{\sim}32$ min at fixed BT of 40 sec for NCMT-7231 $0.1{\mu}m)$). In the viewpoints of total permeate volume ($V_T$), dimensionless permeate flux ($J/J_0$) and resistance of membrane fouling ($R_f$), the optimal $N_2$-BT was 50 sec, which was the longest BT, at 4 min FT for NCMT-5231. It means the longest BT was the most effective to minimize the membrane fouling, and we could acquire the most $V_T$. But the optimal FT for NCMT-7231 was 16 min in the viewpoint of $V_T$, and was 8 min in the viewpoints of $J/J_0$ and $R_f$ at fixed BT of 40 sec. The rejection rates were excellent as $80.6{\sim}96.6\;%$ for turbidity, $35.2{\sim}58.4%$ for $NH_3$-N, $16.3{\sim}45.2%$ for T-P and $16.3{\sim}45.2%$ for $COD_{Mn}$. However, the rejection rate of T-N was very low as $2.7{\sim}13.4%$ and it of TDS below 6.1%.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권5호
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• pp.1-7
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• 2016

The removal of non-aqueous phase liquids (NAPLs) from groundwater using pure water, via pump and treat, is quite ineffective due to their low solubility and hydrophobicity. Therefore, the objectives of pilot tests were to select potentially suitable surfactants that solubilize tetrachloroethylene (PCE) and trichloroethylene (TCE) present as contaminants and to evaluate the optimal range of process parameters that can increase the removal efficiency in surfactant-enhanced soil flushing (SESF). Used experimental method for surfactant selection was batch experiments. The surfactant solution parameters for SESF pilot tests were surfactant solution concentration, surfactant solution pH, and the flow rate of surfactant solution in the SESF pilot system. Based on the batch experiments for surfactant selection, DOSL (an anionic surfactant) was selected as a suitable surfactant that solubilizes PCE and TCE present as contaminants. The highest recovery (95%) of the contaminants was obtained using a DOSL surfactant in the batch experiments. The pilot test results revealed that the optimum conditions were achieved with a surfactant solution concentration of 4% (v/v), a surfactant solution pH of 7.5, and a flow rate of 30 L/min of surfactant solution (Lee and Woo, 2015). The maximum removal of contaminants (89%) was obtained when optimum conditions were simultaneously met in pilot-scale SESF operations. These results confirm the viability of SESF for treating PCE and TCE-contaminated groundwater.

• 멤브레인
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• 제18권1호
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• pp.26-34
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• 2008

본 연구에서 처리수를 이용한 주기적인 역세척은 세라믹 정밀여과에 의한 고도정수처리 시스템에서 막오염을 저감하고 투과선속을 향상시키고자 수행되었으며, 물 역세척 주기(FT) 및 시간(BT)의 영향과 최적 운전조건을 규명하고자 하였다. FT의 영향을 알아보기 위해 일정한 BT 3초에서 FT를 $30{\sim}120$초로 변화시켰고, BT 영향 실험에서 일정한 FT 120초에서 BT를 $3{\sim}12$초로 변화시켰다. 그리고 다른 운전변수인 막간압력차는 1.52 bar, 물 역세척 압력 0.98 bar, 유입유량 0.5 L/min, 공급액의 온도 $20^{\circ}C$로 일정하게 유지하였다. 그 결과, 일정한 BT 3초에서 본 실험 범위의 최적 FT는 30초로, 이것은 빈번한 역세척이 막오염의 저감에 더 효과적임을 의미한다. 그러나 너무 짧은 BT로 인하여 FT의 영향은 크지 않았다. 한편, 일정한 FT 120초에서 BT가 증가함에 따라 막오염에 의한 저항($R_f$)은 감소하고 투과선속(J)과 무차원화한 투과선속 ($J/J_o$)은 증가하는 경향을 나타내어, 최대 BT인 12초에서 가장 많은 총여과부피($V_T$)를 얻을 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권4호
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• pp.51-59
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• 2001

불균질 매질 내 분포하는 비 수용성 유기오염물(NAPL; non-aqueous phase liquid)을 계면활성제를 이용한 원위치 정화 방법으로 정화하는 칼럼 및 박스실험을 실시하였다. Ottawa 모래를 이용한 균질 칼럼실험을 통하여 NAPL에 대한 계면활성제용액의 정화 효율 증가를 검증하였고, 실제 오염지역의 토양을 이용한 칼럼실험을 통하여 불균질 토양에서의 정화 효율을 측정하였으며, 불균질 층리 구조와 단층구조를 모형화한 2차원 박스를 사용한 NAPL 정화 실험을 통하여 불균질 매질에서의 정화 효율을 규명하였다. LNAPL 오염원으로 o-xylene이, DNAPL 오염원으로 PCE(tetrachloroethylene)가 이용되었고, 계면활성제로는 비이온성 올리에마이드(oleamide)가, 매질로는 유류로 오염된 오염지역으로부터 채취한 실제토양과 Ottawa 모래가 실험에 사용되었다. 1% 계면활성제용액과 증류수를 주입하여 NAPL을 세정하였고 가스크로마토그래피(GC)를 이용하여 NAPL의 농도를 분석하였다. 균질 Ottawa 모래충진 칼럼의 경우 계면활성제를 주입할 경우가 증류수를 주입할 때보다 o-xylene의 최대유출농도가 약 460배, 불균질 토양의 경우 약 250배, 불균질 층상구조에서는 약 150배 증가를 나타내었다. 불균질 매질에서 계면활성제를 이용한 세정법(flushing method)으로 NAPL을 정화시, 균질 매질에서의 정화 효과보다는 정화 효율이 감소하나, 여전히 증류수만을 이용한 세정방법보다 훨씬 높은 정화 효과를 보이며, 빠른 시간 내에 NAPL이 정화되었음을 확인하였다. 본 실험을 통하여, 불균질 매질에서의 계면활성제를 이용한 토양세정방법의 효율성이 정량화 되었으며, 계면활성제를 이용한 채수주입법의 현장 적용가능성을 확인하였다.산이온의 탄소의 $\delta$$^{13}$C(PDB)값은 -6.2~0.0$\textperthousand$범위이며, 그 기원은 대수층인 지층내 탄산염암 또는 탄산염 광물의 용해에서 유래한 무기기원 탄소로 해석된다.다.으로 변화하였으며 치료 전에 반응하지 않던 항원에 새롭게 반응하는 항체가 나타나는 경우는 드물었다.ms of chlorophyll-a concentration estimation, however, the accuracy stays very similar compared to that of the CZCS-type algorithm. This is considered to be due to the nature of in-water algorithm which relies on spectral ratio of water-leaving radiances.ethanol의 혈중농도(血中濃度)가 높을수록 더 심(甚)한 혈압강하작용(血壓降下作用)을 나타내며, ethanol 로 인(因)한 이뇨작용(利尿作用)도 ethanol 량(量)이 증가(增加)함에 따라 뇨량(尿量)도 증가(增加)함을 보여 주었다.ults showed that the overall quality of Sullungtang significantly decreased as the parity increased for Hanwoo cows. The Sullungtang extracted from bones of heifer had the best sensory scores as well as nutritional quality when compared to those extracted from the cows with parity. Therefore,

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.215-218
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• 2004

The electrokinetically enhanced soil flushing had a great potential to improve the removal efficiency of polycyclic aromatic hydrocarbons (PAHs) from low permeable soils. A semi-pilot study of surfactant-enhanced electrokinetic process was investigated for the removal of phenanthrene from kaolinite. A nonionic surfactant, Tergitol 15-S-12 at 10 g/L was introduced as a flushing agent and 0.001M of sodium chloride was used as an electrolyte. When the constant voltage of 100 V was applied to the system for 25 days, only 0.66 kWh of electric power was consumed and the amount of electroosmotic flow was 6.9 L. The removal efficiency of phenanthrene was about 40 % and it can be improved by increasing the ion concentration of the flushing solution or the applied voltage.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.401-401
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• 2010

현대사회로 들어오면서 과거와 달리 외부에 있던 화장실이 내부로 들어오면서 변기 뚜껑을 닫지 않고 toilet flushing을 할 때 배변에 포함된 다량의 장티푸스, 포도상 구균 같은 종류의 세균이 화장실 곳곳에 퍼짐에 의하여 면역력이 약한 경우 여러 가지 세균성 질환 및 2차 감염을 통하여 장티푸스 및 피부 질환 등이 발생한다. 본 연구에서는 이런 감염을 최소화하기 위한 방법으로 플라즈마를 이용한 세변기 표면의 오염 방지처리 기술을 개발하는 것을 목표로 한다. 일차적으로 여러 가지 운용 조건에서 오염의 정도를 파악하고자 배변의 양에 따라 toilet flushing 시 피부 오염의 물질 노출 정도를 평가 하였다. 실험 방법은 배변을 모사하여 toilet system에 넣고 물을 내려 무게에 따른 물 튀김 정도와 위치 분포를 분석하였다. 밀가루 반죽의 무게가 증가하면서 피부에 닿는 물 튀김 면적이 특정 무게에서 최대 60.02 mm2까지 증가하다 감소했다. 또한 실제 측정 결과를 통하여 물 튀김의 분포가 뒤쪽에 집중되는 것을 볼 수 있었다. 이와 같이 실제 toilet flushing시 세균에 의하여 피부 오염 및 국부 감염이 발생할 수 있다는 것을 확인할 수 있었다. 또한 비데 동작 시 변기 내부에 잔존하는 세균 자체가 확산되는 정도를 3차원 유체 역학 모델링으로 예측하였다. 앞으로 세변기 뚜껑의 플라즈마 표면처리 및 toilet flushing 유로 디자인 개선을 통해 세균의 잔류 및 퍼짐을 최소화함으로써 최종적으로 세균성 질환을 줄일 수 있는 방법을 개발하는 것이 본 연구의 1단계 목표다.

• 한방안이비인후피부과학회지
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• 제35권3호
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• pp.123-132
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• 2022

Objectives : The purpose of this study is to report a case of erythematotelangiectatic type rosacea and peripheral facial palsy improved by Korean medicine treatment with Soshioho-tang gagambang. Methods : The patient visited our clinic due to facial flushing and peripheral facial palsy symptoms. Based on Sanghallon provision, we treated this case with Soshiho-tang gagambang. The result of treatment was evaluated by Visual Analogue Scale(VAS), Dermatology Life Quality Index(DLQI) and House-Brackmann Grading System(HBGS). Results : After 12 days of taking Soshiho-tang gagambang, VAS of rosacea was decreased from 9 to 4 and DLQI was decreased from 22 to 5. After treatment, rosacea with facial flushing was improved and HBGS was reduced from 3 to 1. Conclusions : This study shows the possibility of taking Soshiho-tang gagambang for erythematotelangiectatic type rosacea and peripheral facial palsy derived from stress, fatigue and sleep disturbance according to Sanghallon provision.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.146-146
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• 2021

A contamination event occurring in water distribution networks (WDNs) needs to be handled with the appropriate mitigation strategy to protect public health safety and ensure water supply service continuation. Typically the mitigation phase consists of contaminant sensing, public warning, network inspection, and recovery. After the contaminant source has been detected and treated, contaminants still exist in the network, and the contaminated water should be flushed out. The recovery period is critical to remove any lingering contaminant in a rapid and non-detrimental manner. The contaminant flushing can be done in several ways. Conventionally, the opening of hydrants is applied to drain the contaminant out of the system. Relying on advanced information and communication technology (ICT) on WDN management, warning and information can be distributed fast through electronic media. Water utilities can inform their customers to participate in the contaminant flushing by opening and closing their house faucets to drain the contaminated water. The household draining strategy consists of determining sectors and timeslots of the WDN users based on hydraulic simulation. The number of sectors should be controlled to maintain sufficient pressure for faucet draining. The draining timeslot is determined through hydraulic simulation to identify the draining time required for each sector. The effectiveness of the strategy is evaluated using three measurements, such as Wasted Water (WW), Flushing Duration (FD), and Pipe Erosion (PE). The optimal draining strategy (i.e., group and timeslot allocation) in the WDN can be determined by minimizing the measures.

• 대한치과보철학회지
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• 제36권1호
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• pp.64-80
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• 1998

The risk of cross-contamination in dental clinic is very high. Those who are engaged in dental clinic are exposed to various microorganisms in saliva and blood of patient. Potential possibility of cross-contamination of patient to patient, patient to dentist, dentist to laboratory technician always exist, which is important in the view of public health. It is well known that microorganisms may cause cross-contamination by suck-back of microorganisms into the water supply line or air supply line of dental unit and sprayed back into the next patient's oral cavity. The majority of microorganisms coming from dental unit are water microorganisms from the main water supply which have colonized the tube within the units and multiplied in the relatively warm and stagnant conditions. The purpose of this study is to measure the extent of microbial contamination of dental unit and ultrasonic scaler, to evaluate that dental unit water supply is suitable for drinking water, and to assess the effect of flushing on reduction of microbial contamination of dental unit and ultrasonic scaler. In the first experiment, water samples(50ml) from 20 dental units and 10 ultrasonic scalers in Seoul National Univ. Hosp. were tested for the presence of coliform. The samples were filtered by membrane filtration technique.(Microfil system, Millipore Co. U. S. A.) The filter was then placed onto MacConkey agar plate and the plates with filter on it were incubated aerobically at $37^{\circ}C$ for 5 days. The colors and shapes of colonies were examined if those were coliform. To verify the presence of coliform, the colonies were inoculated into phenol red lactose broth and incubated aerobically at $37^{\circ}C$ for 2 days. The fomation of gas was observed. In the second experiment, water samples from 20 handpieces, 10 ultrasonic scalers and 30 A/W syringes after 0, 2, 4, 6 min. flushing respectively were taken. $200{\mu}l$ water samples were spreaded on Brain Heart Infusion agar plate and the plates were incubated aerobically at $37^{\circ}C$ for 5 days. The number of colony was counted. The results obtained were summarized as follows 1. The water from dental unit and ultrasonic scaler was not suitable for drinking water. 2. No coliform was founded in dental unit and ultrasonic scaler water supply. 3. The number of colony of dental unit and ultrasonic scaler was highest in the group of o min. flushing(p<0.05). 4. There was no statistically significant difference in the extent of microbial contamination among handpiece, ultrasonic scaler and A/W syringe (p>0.05). 5. The number of colony was lowest in the group of 4 min. flushing, but there was no statistically significant difference among 2, 4, 6 min. flushing groups.(p>0.05) 6. It is recommended to flush dental unit water line for 4 min. after use on each patient.

• 멤브레인
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• 제11권4호
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• pp.190-203
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• 2001

본 연구에서는 4종류의 탄소계 관형 세라믹막으포 제지공장의 방류수를 물로 주기적 역세척하면서 한외여과하였을 때, 물 역세척 주기와 막간압력차 (TMP), 유량의 영향과 최적운전조건을 규명하였다. 역세척 시간(BT)은 3초로 고정하였고, 역세척 주기(FT)는 여과시간을 15~60초로, TMP는 1.00~2.50$kg_{f}$/$cm^2$로, 유량은 0.25~1.75 L/min로 변화시켜 가면서 각각 그 영향을 살펴보았다. 또한, 최적조건은 무차원 투과선속 (J/$J_O$) 및 총 여과부피 ($V^T$), 막오염에 의한 저항 ($R^f$)의 측면에서 고찰하였다. 그 결과 최적 역세척 주기는 BT/FT=0.20로, 빈번한 역세척은 막오염을 감소시켰다. 한편, $V^T$측면에서 최적 TMP는 1.00~1.55$kg_{f}$/$cm^2$로 TMP 증가는 막오염을 심화시켜 투과선속을 감소시켰으나, 유량 증가는 막오염을 감소시켜 투과선속을 증가시키는 경향을 보였다. 본 연구에서 사용한 탄소계 세라믹 분리막에 의한 오염물질 제거율은 탁도의 경우 88~98%로 높았으나, $COD_{cr}$의 경우 48~72%, 총용존고형물 (TDS)의 경우 37~76%였다.