• 한국환경보건학회지
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• 제38권2호
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• pp.128-135
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• 2012

Objectives: This study was aimed at determining the optimum coagulation dosage in a high turbid kaolin water sample using streaming current detection (SCD) as an alternative to the jar test. Methods: SCD is able to optimize coagulant dosing by titration of negatively charged particles. Kaolin particles were used to mimic highly turbid water ranging from 50 to 600 NTU, and polyaluminum chloride (PAC, 17%) was applied as a titrant and coagulant. The coagulation consisted of rapid stirring (5 min at 140 rpm), reduced stirring (20 min at 70 rpm), and settling (60 min). To confirm the coagulation effect, a jar test was also compared with the SCD titration results. Results: SCD titration of kaolin water samples showed that the dose of PAC increased as the pH rose. However, supernatant turbidity less than 1 NTU after coagulation was not achieved for high turbid water by SCD titration. Instead, a conversion factor was used to calculate the optimum PAC dosage for high turbid water by correlating a jar test result with that from an SCD titration. Using this approach, we were able to successfully achieve less than 1 NTU in treated water. Conclusions: For high turbid water influent in a water treatment plant, particularly during summer, the application of SCD control by applying a conversion factor can be more useful than a jar test due to the rapid calculation of coagulation dosage. Also, the interpolation of converted PAC dose could successfully achieve turbidity in the treated water of less than 1 NTU. This result indicates that an SCD system can be effectively used in a water treatment plant even for high turbid water during the rainy season.

• 대한수혈학회지
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• 제29권3호
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• pp.240-252
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• 2018

점탄성 응고 검사법은 전혈 검사법으로 혈장성분뿐 아니라 응고 과정의 세포 기반 측면까지 동시에 볼 수 있는 방법이다. 프로트롬빈시간이나 활성화부분트롬보플라스틴시간과 같은 기존의 응고 검사법과 달리 이 검사는 현장 현시 검사로 즉시 시행할 수 있다. 점탄성 응고 검사법은 사망률 등의 예후 예측 인자이고, 응고 장애를 좀 더 예민하게 감지하여 결과적으로 출혈을 줄여주는 효과를 줄 수 있다. 점탄성 응고 검사 결과를 이용한 수혈 전략이 수혈 요구량을 줄여주었다고 보고되기도 하였다. 아직 이 방법의 정확성과 신뢰도에 대한 우려가 있기도 하지만, ROTEM 등의 점탄성 응고 검사법은 환자혈액관리에 응용하는 것은 유용할 것이다.

• Environmental Engineering Research
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• 제11권1호
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• pp.45-53
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• 2006

Conventional coagulation is still the main treatment process for algae removal in water treatment. The coagulation efficiency can be significantly improved by the preoxidation of algae-containing water. Jar test was conducted to determine the optimal condition for the removal of diatoms, especially Cyclotella sp. by preoxidation and the subsequent coagulation. The effects of various concentration of PAC (Polyaluminum chloride) on coagulation with and without preoxidation using chlorine or potassium permanganate at different pHs (7.7 and 9.0) were evaluated. At pH 7.7, preoxidation with 2ppm $Cl_2$ followed by coagulation with 7.5 ppm PAC coagulant could reduce Cyclotella sp. concentration by 86%. At pH 9.0, preoxidation with 1 mg $KMnO_4/L$ followed by coagulation with 12.5 ppm PAC coagulant reduced Cyclotella sp. concentration by 85%. Non-linear regression was applied to determine the optimal condition. At pH 7.7 and 9.0, R was over 0.9, respectively. The pH of algal blooming water is over 9.0. Algae (diatom; Cyelotella sp.) can be controlled in the following ways: preoxidation with 1 mg $KMnO_4/L$ followed by coagulation with 12.5 ppm PAC coagulant can remove 80% algae from water. If water pH is adjusted to 7.7, it was expected that less amount of coagulant (7.5 or 10 mg PAC /L) after preoxidation ($Cl_2$ 2 ppm or $KMnO_4$ 0.33, 1 ppm) would be needed to achieve similar level of algae removal. The oxidation with 0.33ppm $KMnO_4$ followed by coagulation with 7.5 ppm PAC coagulant was preferable due to cost-effectiveness of treatment condition and color problem after treatment.

• 약학회지
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• 제56권6호
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• pp.382-389
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• 2012

Effects of citrate-capped silver nanoparticles (AgNPs) on the blood coagulation and platelet aggregation were investigated using whole blood, platelet rich plasma (PRP) and washed platelet obtained from SD male rats. To confirm the stability of AgNPs in the test, size distribution of the nanoparticles was measured in the vehicles including distilled water, serum, and platelet buffers. The average size of AgNPs was 20 nm in the vehicles, which means that the stability was maintained during the whole experimental period. When blood coagulation was monitored by using whole blood impedance aggregometer, coagulation was not observed at the concentration of 1, 10 and 50 ppm. Platelets in plasma or in buffer were not aggregated by AgNPs at the concentration of 1, 2 and 4 ppm, respectively. The test concentration of AgNPs could not be increased because the dark color of the nanoparticles impeded the transmission of light, which is an indicator of aggregation. Although the blood or platelets were pre-activated by collagen, thrombin, or ADP with sub-threshold level, aggregation was not observed at the test concentration. Microscopic observation also supported the result obtained by the aggregometer.

• 청정기술
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• 제6권1호
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• pp.27-38
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• 2000

초고속응집침전공정(URC)은 가중응집제(WCA)를 첨가하고 슬러지를 반송시켜 응결핵으로서의 역할을 수행시킴으로서 floc의 성장속도를 향상시키고, 입자표면의 흡착을 활성화하여 유기물, 중금속, 인 등 수중에 존재하는 오염물을 보다 효율적으로 제거하며, 기존의 응집 공정에 비하여 침전성을 향상시킬 수 있다. 현재까지 하수처리장과 하천, 호소에서 수행된 URC pilot-test와 Jar-test의 결과를 비교 검토하여 가중 응집제와 반송 슬러지에 대한 오염물 제거특성에 대한 연구가 수행되었으며, 수자원의 재이용을 위한 가능성을 평가하였다.

• 한국환경과학회지
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• 제8권6호
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• pp.717-724
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• 1999

This experiment was performed on three parts with prepared coagulants. (1) The characterization of coagulation for PACI coagulants. (2) Comparison of the characterization of coagulation with PAS and PACI coagulants. And (3) Comparison of the characterization of coagulation for the addition of calcium with PACI. Coagulation experiments were conducted with several dosages and pH for each coagulants. For the characterization of coagulation with PACI coagulants, coagulation of Nakdong river waters with three PACls (r=2.0, 2.2, 2.35) showed that the effectiveness of the three coagulants can be considered as r=2.2 > 2.0 > 2.35 which are also the order of higher polymeric aluminum contents. For the comparison of the characterization of coagulation for PAS and PACI coagulants, PAS (r=0.75) coagulants was more effective than other coagulant for the removal of organic matters by sweep floc mechanism with $A;(OH)_{3(S)}$. For comparison of the characterization of coagulation for the addition of calcium with PACI, the presence of divalent cation like $Ca^{2+}$ was supposed to influence the complex formation of organic anions. From the result of test on coagulation at various pH ranges, the PACI was least affected by the coagulation pH, and the addition of calcium to PACI was very effective for the removal of turbidity and organic materials over broader pH range (pH 4-9).

• 상하수도학회지
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• 제19권4호
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• pp.429-436
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• 2005

A coagulation/ultrafiltration membrane hybrid system was operated to treat river water with capacity of $0.06m^3/d$. The impact on membrane fouling by flux and linear velocity was investigated. It is known that pressure increase is proportional to flux increase. However, pressure increase was much faster than theoretical value in the pilot plant test. So it was suggested that flux was on important factor in ultrafiltration of continuous operation. Membrane fouling was decreased when linear velocity was increased. This phenomenon was found more obviously without coagulation. With the combination of coagulation and sedimentation, membrane fouling was not reduced conspicuously. Big particles formed during coagulation and sedimentation were destroyed by feed and circulation pumping, which resulted in little effect on membrane fouling reduction. The degree of destruction was similar at various linear velocities. In this study, the hollow fiber membrane was used and the system was operated in pressure type module. In case of the system used in this study, membrane fouling has been affected lightly by linear velocity variation when coagulation pretreatment was applied.

• 상하수도학회지
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• 제19권4호
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• pp.473-479
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• 2005

Applying enhanced coagulation is not uncommon not only to improve water quality but also to obtain economical advantages in water treatment. In this study, the economical evaluation was investigated with considering dosage of coagulant, produced sludges and usage of activated carbon with two different water sources. To simulate the granular activated carbon(GAC) adsorber mini-column test was adapted. Even if there were some variation according to the source waters, the life time of GAC was extended 60 to 110days with adding 2.5 to 3 times of coagulant in enhanced coagulation. With assumption of changing GAC adsorber at 50% of breakthrough the total treatment cost can be reduced to range from 25% to 44% with adapting the enhanced coagulation. The obtained value can not be generalized because the value can be varied by water quality and cost of the GAC or coagulant. However, the evaluation can be basis starting point to find optimum operation methods for the drinking water treatment which has plan to adapt GAC adsorber.

• Environmental Analysis Health and Toxicology
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• 제23권4호
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• pp.285-290
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• 2008

Effects of titanium dioxide nanoparticles on blood coagulation and platelet aggregation were investigated using diluted whole blood and platelet rich plasma (PRP) solution prepared from human and rat blood, respectively. Blood coagulation was monitored by using a whole blood impedance aggregometer and titanium dioxide nanoparticle (10, 20, and 40 ppm) did not show any effect on the coagulation both in human and in rat blood. When platelet aggregation was measured by turbidometric method after addition of titanium dioxide nanoparticles to PRP solution with final concentrations of 1, 5 and 10 ppm. no aggregation was observed.

• 한국습지학회지
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• 제15권1호
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• pp.1-8
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• 2013

도시유역에서 강우시에 발생되는 합류식 하수관거 월류수(CSOs; Combined Sewer Overflows)을 처리하기 위해 물리화학적 처리기법을 적용한 실증규모의 응집침전시스템을 개발하였다. 이에 앞서 응집침전시스템은 lab-test를 통해 도출된 최적의 설계조건이 실증규모로 증설할 시에 설계인자가 제대로 반영되었는지 평가가 필요하며, 최적조건에 따라 설계에 반영하였다 하더라도 대상원수의 유입특성에 따라서도 처리결과에 대한 평가가 다를 수가 있다. 이에 본 연구에서는 청주하수 처리장에 유입되는 CSOs를 대상으로 각각 $1m^3$/일과 $100m^3$/일의 CSOs를 처리할 수 있는 실험실규모 및 실증규모의 장치를 통해 실험을 수행하였다. 실증규모의 시스템을 운전하여 lab-test에서 도출된 설계인자와의 상사성을 검토하고, 이를 바탕으로 높은 처리효율을 유지하기 위한 운전인자를 적용하여 CSOs를 처리함에 있어 그 가능성을 평가하였다. 그 결과, 실험실 규모의 설계조건과 상사성을 만족하는 인라인믹서와 응집반응조의 조건을 도출할 수 있었으며, pilot-test를 운전하기 위한 적정 응집제 주입량을 도출하였고, 결과적으로 실증규모의 시스템에서도 CSOs를 대상으로 높은 효율의 응집침전처리를 가능하게 할 수 있었다.