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        검색결과 28

        1.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, effects of five raw water quality parameters (turbidity, odor compounds caused by algae, filter clogging caused by algae, pH increase caused by algae, and organic matter) on improvements and operations costs of typical water treatment plant (WTP) were estimated. The raw water quality parameters were assumed the worst possible conditions based on the past data and costs were subsequently estimated. Results showed that new water treatment facilities were needed, such as a selective intake system, an advanced water treatment processes, a dual media filter, a carbonation facility, and a re-chlorination facility depending on water quality. Furthermore, changes needed to be made in WTP operations, such as adding powered activated carbon, increasing the injection of chlorine, adding coagulation aid, increasing the discharge of backwashed water, and increasing the operation time of dewatering facilities. Such findings showed that to reliably produce high-quality tap water and reduce water treatment costs, continuous improvements to the quality of water sources are needed.
        4,300원
        2.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Desalination plants are generally studied with higher operating costs compared to water supply facilities. This study was conducted to reduce the cost of water production and to preserve existing water resources. Therefore, the purpose of this study was to utilize the control valves to increase maximum efficiency, thereby reducing the power of the pumps and operating costs. Specific energy consumption was shown to reduce the process operating power by up to 1.7 times from 6.17 to 3.55 kWh/m3 based on seawater reverse osmosis 60 bar. In addition, the water intake process was divided into pre, inter, and post-according to the use method of blasting, and the water treatment process was divided into pre, inter, and post blending. In order to reduce power consumption, the blending process was combined to operate the facility, which resulted in the reduction of power consumption in the order post > pre-inter> inter blending.
        4,000원
        4.
        2018.11 구독 인증기관·개인회원 무료
        본 실험에서는 대청호에서 발생한 남조류를 대상으로 SiC(Silicon carbide) 평막의 최적 운전조건을 도출하고자 하였다. 이를 위해 원수 농도에 따른 투과플럭스, 응집제 주입 조건, Air scrubbing 조건, 역세척(Backwashing) 유량 및 시간, 여과 및 역세척 시간, 응집제 종류 및 주입 농도 등에 대해 안정적으로 운전이 가능한 최적 조건을 도출하였다. 특히, 저농도의 응집제 주입에도 음전하를 띄는 조류 입자들과 전기적으로 중화를 일으켜서 생성된 미세 플럭들이 SiC 평막의 막표면에서 투수성을 증가시킨 것으로 사료된다. 이를 통해 도출된 설계인자로 제작한 Pilot Plant를 조류 제거시 적용하고자 한다. 본 연구는 환경부의 “환경정책기반공공기술개발사업”으로 지원받은 과제입니다.
        5.
        2018.11 구독 인증기관·개인회원 무료
        본 연구는 비용매 상분리법(nonsolvent induced phase separation, NIPS)을 사용하여 제조한 분리막의 배출수 처리 현장 적용성 test를 위한 최적 유효막 길이 선정 하기 위해, 동일한 원수, 기본 공정 조건으로 유효막 길이를 변화시켜 운전에 따른 역세 효율 및 운전압을 관찰하였다. 동일한 공정조건에서 유효막 길이의 변화를 주어 500㎜, 1,000㎜, 1,500㎜의 유효막 길이에 따라 1.5일간 고탁도의 가혹한 조건에서 공정을 지속하여 측정을 실시하였다. 유효막 길이별 운전 결과 유효막 길이에 따른 역세에 의한 효율차이를 확인할 수 있었으며 고탁도의 원수를 사용하여 중공사 막의 내부 폐색이 진행되었으며 유효막 길이가 길수록 폐색되지 않은 bore쪽으로만 역세가 진행되어 여과 후 역세에 의한 회복이 현저히 떨어짐을 확인하였다.
        9.
        2006.02 구독 인증기관 무료, 개인회원 유료
        Analysis of design parameters of residual treatment process at eight model water treatment plants, which were located in the four major watersheds, showed that there were large differences between those design parameters and the actual conditions. In this background, a new procedure was proposed and applied to the Chungju water treatment plant as an example of the optimum design of residual treatment process based on the characteristics of raw water. In this design example, a filter backwash recycle system consisting of a surging tank and sedimentation basin was newly proposed for more safe recycle of spent backwash water. It is expected that the design procedure proposed in this study would be estimated as a meaningful attempt to develope new design procedure for the domestic water industry.
        5,400원
        10.
        1997.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Vibrio mimicus is a closely related species with V. cholerae, and has been reported to be associated with gastrointestinal infections. Although extraintestinal infections of these vibrios have also been reported in Japan and Southeast Asia. But little research papers on V. mimicus was reported in Korea. Therefore, we tried to isolate V. mimicus from the environmental sea water from April to July in Pusan, Korea. Among the isolated strains, we selected the strongest hemolytic strain and then named V. mimicus SM-9. In this paper, we checked the antibiotic susceptibility and psychrotrophic characteristics of the isolated strain. Hemolytic activity of the hemolysin produced by the isolated strain was also measured. V. mimicus was not detected from the sea water samples in April and May, but its detection rate was relatively high in June and July in Pusan, Korea. The bacteriological characteristics of V. mimicus SM-9 were Gram-negative rods, motile, oxidase positive, Voges-Proskauer negative and sucrose negative. In 23 kinds of antibiotics susceptibility test, V. mimicus SM-9 showed susceptibility to the most of antibiotics submitted while it was resistive against lincomycin, oxacillin, rifampin and vancomycin. Hemolytic activity of the hemolysin produced by V. mimicus SM-9 was highest in stationary phase of the growth curve in BHI broth at 37℃ and its activity was reached 18 HU per ml of culture supernatant. For checking the psychrotrophic property of V. mimicus SM-9, the decreasing rate of the strain in phosphate buffer solution and yellowtail flesh homogenate was examined during the storage at 4, 0, -4 and -20℃. The decreasing rates of the selected strain stored in phosphate buffer solution were greater than those in fish homogenate. Decreasing rates of V. mimicus SM-9 stored in phosphate buffer solution were not significantly different by the storage temperatures. The viable cell counts of the strain were decreased as 5 log cycles after 120 hours at all the tested temperatures. While decreasing numbers of the strain in fish homogenates were 2-4 log cycles after 120 hours. The decreasing pattern of the strain numbers were very slow after 200 hours at all the stored temperatures.
        4,000원
        11.
        2023.05 KCI 등재 서비스 종료(열람 제한)
        This study used a batch DAF (dissolved air flotation) jar tester to evaluate the algae removal efficiency of alum and PAC coagulants during coagulation, flocculation, and flotation. Optimal coagulant dosages were 0.06 ~ 0.15 mL/L (12.0 ~ 26.0 mg Al/L,17%), 0.08 ~ 0.20 mL/L (10.0 ~ 24.0 mg Al/L, 12%), 0.25 ~ 0.30 mL/L (25.0 ~ 30.0 mg Al/L, 10%) for PAC, and 3.0 ~ 5.0 mL/L (81.0 ~ 135.0 mg Al/L, 2.7%) for alum. Turbidity of treated water was 1.0 ~ 2.0 NTU in optimal coagulation, flocculation, and flotation conditions for the four coagulants types. The amount of coagulant injected tended to decrease with increasing Al content in the coagulant, as follows : 17% PAC < 12% PAC < 10% PAC < 2.7% alum. Turbidity removal efficiencies were in the order of 12% PAC (93.6%) > 10% PAC (92.7%) > 17% PAC (91.3%) > 2.7% Alum (88.1%).
        12.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        Background: Sedum takesimense Nakai has been used as folk medicine in Korea. The present study aimed to determine the biological activity of S. takesimense by investigating the anti-inflammatory effects of S. takesimense water extract (SKLC) on the lipopolysaccharide-induced inflammatory response in RAW 264.7 cells. Methods and Results: Cytotoxicity of SKLC on RAW 264.7 cells was determinded by performing MTS assay was found to have no cytotoxic effect on RAW 264.7 cells at a concentration range of 62 - 500 ㎍/㎖. Further, pretreatment of SKLC inhibited lipopolysaccharide-induced nitric oxide (NO) production in a dose-dependent manner. To determined the inhibitory mechanisms of SKLC on inflammatory mediators, we assessed the inducible nitric oxide synthase (iNOS) and cyclooxygnease-2 (COX-2) pathways. The activities of these pathways were decreased in a dose-dependent manner by SKLC. The production of tumor necrosis factor- α (TNF-α), interleukin (IL)-1β‚ and IL-6 were also reduced. Conclusions: These results suggest that the down regulation of iNOS, COX-2, TNF-α, IL-1β‚ and IL-6 expression by SKLC are mediated by the down regulation of nuclear factor-κB (NF-κB) activity, a transcription factor necessary for pro-inflammatory mediators. This might be the mechanism underlying the anti-inflammatory effects of SKLC.
        13.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.
        14.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.
        18.
        2013.04 KCI 등재 서비스 종료(열람 제한)
        This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 ㎎ / L, THMFP> 70 ㎍ / L, Chl-a> 30 ㎎/ ㎥or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.
        19.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        Eucommia ulmoides OLIVER (EU) is a traditional Korean herbal used for the treatment of rheumatoid arthritis (RA). In the present study, the molecular pharmacology basis of its anti-inflammatory effect is revealed in this work, EU was studied in lipopolysaccharide (LPS)-activated macrophage cells (RAW 264.7) as an established inflammation model. After activation, nitric oxide (NO) production and iNOS mRNA were measured by using a colorimetric assay (Griess reagent), and reverse transcription polymerase chain reaction (RT-PCR), respectively. The change in the content of PGE2, TNFα, and IL-6 was concurrently monitored by ELISA. In results, we found that in the concentration range without showing cytotoxicity, EU produced a remarkable anti-inflammatory effect and showed a dose-dependent inhibition of LPSinduced NO production. Compared with indomethacin, EU has more potency and a specific action of NO inhibition, PGE2, IL-6, and TNF-α inhibition. These results suggest that EU may be a suitable herbal medicine to yield the greatest anti-inflammatory activity for food additives and medicine.
        20.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to investigate the characteristics of disinfection by-products (DBPs-trihalomethanes (THMs), haloacetic acids (HAAs) and haloacetonitriles (HANs) formation in chlorination of principal raw waters used for drinking water on Jeju Island, Korea. The domestic water supply of other area and humic acid solution (HA) were used as a reference point. The effects of chlorine contact time, solution temperature and pH on DBPs formation potential (DBPFP) were investigated for raw waters. In addition, the effect of Br- was studied for HA. The DBPFP (THMFP, HAAFP and HANFP) were increased with increasing chlorine contact time. Comparing the individual DBPFPs for raw waters, they decreased in the order of HAAFP > THMFP ≥ HANFP. As the solution temperature was increased, the THMFP, HAAFP and HANFP increased. With increasing the solution pH, the THMFP was increased, but HAAFP and HANFP were decreased. With the addition of 0.3 mg/L Br- for HA, the DBPFP was increased and the major chemical species changed: from trichloromethane to dibromochloromethane and tribromomethane for THMs; from dichloroacetic acid and trichloroacetic acid to tribromoacetic acid for HAAs; and from dichloroacetonitrile to dibromoacetonitrile for HANs.
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