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        검색결과 134

        81.
        2021.12 KCI 등재 서비스 종료(열람 제한)
        In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125∼0.600 mm), conical-to-cylindrical ratio (1.5∼3.0), and operating time (1∼20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCODCr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.
        82.
        2020.10 KCI 등재 서비스 종료(열람 제한)
        In this study, the necessity for a village unit Automatic Weather System (AWS) was suggested to obtain correct agricultural weather information by comparing the data of AWS of the weather station with the data of AWS installed in agricultural villages 7 km away. The comparison sites are Hyogyo-ri and Hongseong weather station. The seasonal and monthly averaged and cumulative values of data were calculated and compared. The annual time series and correlation was analyzed to determine the tendency of variation in AWS data. The average values of temperature, relative humidity and wind speed were not much different in comparison with each season. The difference in precipitation was ranged from 13.2 to 91.1 mm. The difference in monthly precipitation ranged from 1.2 to 75.4 mm. The correlation coefficient between temperature, humidity and wind speed was ranged from 0.81 to 0.99 and it of temperature was the highest. The correlation coefficient of precipitation was 0.63 and the lowest among the observed elements. Through this study, precipitation at the weather station and village unit area showed the low correlation and the difference for a quantitative comparison, while the elements excluding precipitation showed the high correlation and the similar annual variation pattern.
        83.
        2019.09 KCI 등재 서비스 종료(열람 제한)
        In this study, the effect on the stability of Aerobic Granular Sludge (AGS) with different Carbon/Nitrogen (C/N) ratios was investigated. The C/N ratios were controlled to 10.0, 7.5, 5.0, and 2.5 using the sequencing batch reactor, and the results showed that the removal efficiency of organic matter and total nitrogen decreased simultaneously with the decrease of C/N ratio. The removal efficiency of organic matter and total nitrogen at C/N ratio of 2.5 was 70.7% and 52.3% respectively. In addition, the AGS/mixed liquor suspended solids (MLSS) ratio showed a tendency to decrease from 85.7% to 73.7%, while the sludge volume index showed a tendency to increase from 82 mL/g to 102 mL/g as the C/N ratio decreased. At the same time, the apparent deviation of polysaccharide (PS) content in extracellular polymeric substances was observed, and polysaccharides/protein (PS/PN) ratio decreased from 0.62 to 0.31 as the C/N ratio decreased. Optical microscope observations showed that the reduction in C/N ratio caused the growth of filamentous bacteria and significantly affected the stability of AGS.
        84.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        This study evaluated the biosorption properties of calcium ion using Aerobic Granular Sludge (AGS). A sequencing batch reactor was used to induce the production of Extracellular Polymeric Substances (EPS) through salinity injection, and the calcium ion adsorption efficiency was analyzed by a batch test. The EPS contents showed significant changes (104-136 mg/g MLVSS) at different salinity concentrations. The calcium ion adsorption efficiency was highest for AGS collected at 5.0% salinity, and it was confirmed that the biosorption efficiency of AGS was increased owing to the increase in EPS content. The results of the Freundlich isotherms showed that the ion binding strength (1/n) was 0.3941-0.7242 and the adsorption capacity (Kf) was 2.4082-3.3312. The specific surface area and the pore size of the AGS were 586.1 m2/g and 0.7547 nm, respectively, which were not significantly different from each other. It was confirmed that the influence of biological properties, such as EPS content, was relatively large among the factors affecting calcium ion adsorption.
        85.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.
        86.
        2019.07 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the effect of high-salinity wastewater on the microbial activity of Aerobic Granule Sludge (AGS). Laboratory-scale experiments were performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen removal efficiency, sludge precipitability, and microbial activity were evaluated under various salinity injection. The COD removal efficiency was found to decrease gradually to 3.0% salinity injection, and it tended to recover slightly from 4.0%. The specific nitrification rate was 0.043 0.139 mg NH4 +-N/mg MLVSS·day. The specific denitrification rate was 0.069 0.108 mg NO3 --N/mg MLVSS·day. The sludge volume index (SVI30) ultimately decreased to 46 mL/g. The specific oxygen uptake rate decreased from an initial value 120.3 to a final value 70.7 mg O2/g MLVSS·hr. Therefore, salinity injection affects the activity of AGS, causing degradation of the COD and nitrogen removal efficiency. It can be used as an indicator to objectively determine the effect of salinity on microbial activity.
        87.
        2019.07 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale’s experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 0.134 mg NO3 --N/mg MLVSS (mixed liquor volatile suspended solid)·day. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index (SVI30) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.
        88.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to confirm the applicability of aerobic granular sludge (AGS) in the advanced sewage treatment process. Simulated influent was used in the operation of a laboratory scale reactor. The operation time of one cycle was 4 h and the reactor was operated for six cycles per day. The volume exchange ratio was 50%. The influent was injected in divisions of 25% to increase the removal efficiency of nitrogen in every cycle. As a result, the removal efficiencies of CODCr and TN in this reactor were 98.2% and 76.7% respectively. During the operation period, the AGS/MLVSS concentration ratio increased from 70.0% to 86.7%, and the average SVI30 was 67 mL/g. The SNR and SDNR were 0.073 0.161 kg NH4 +-N/kg MLVSS/day and 0.071 0.196 kg NO3 --N/kg MLVSS/day respectively. These values were higher or similar to those reported in other studies. The operation time of the process using AGS is shorter than that of the conventional activated sludge process. Hence, this process can replace the activated sludge process.
        89.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        To predict annual energy production (AEP) accurately in the wind farm where located in Seongsan, Jeju Island, Equivalent wind speed (EQ) which can consider vertical wind shear well than Hub height wind speed (HB) is calculated. AEP is produced by CFD model WindSim from National wind resource map. EQ shows a tendency to be underestimated about 2.7% (0.21 m/s) than HB. The difference becomes to be large at nighttime when wind shear is large. EQ can be also affected by atmospheric stability so that is classified by wind shear exponent (). AEP is increased by 11% when atmosphere becomes to be stabilized ( > 0.2) than it is convective ( < 0.1). However, it is found that extreme wind shear ( > 0.3) is hazardous for power generation. This results represent that AEP calculated by EQ can provide improved accuracy to short-term wind power forecast and wind resource assessment.
        90.
        2015.08 KCI 등재 서비스 종료(열람 제한)
        The Ministry of Trade, Industry and Energy is now placing emphasis on the importance of a new and renewable energy resource map service as an essential means of promoting the dissemination and adoption of renewable energy and other related industrial activities. To raise satisfaction with the new and renewable energy resource map service and promote its utilization, a survey was conducted on a sample group with an academic research background, i.e. employees of the Korea Institute of Energy Research (KIER) who have a thorough understanding of the technological concepts behind the new and renewable energy resource map. Statistical analysis of the survey results showed a high level of overall satisfaction with the web service for the new and renewable energy resource map. Therefore, it was concluded that the development of practical contents rather than the enhancement of web service convenience is required. A statistically significant trend was also observed whereby, the longer the professional career of the survey respondents, the greater their perception and utilization of, and satisfaction with, the enhanced service, which indicates that their level of understanding and utilization of technological concepts corresponds to their research experience record. In addition, the results obtained from the questionnaires regarding the evaluation of the utilization value of the resource map service indicated that use of the service was equally high in terms of political, business and academic applications. The results confirmed the need to develop multidimensional resource map contents that can be applied to as many fields as possible, rather than focusing on a specific terrain.
        91.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        In order to decide the location of appropriate onshore wind farm with higher potential wind energy, several decision processes using Geographic Information System (GIS) including Digital Elevation Map (DEM) were proposed and we also estimated the wind resources through the proposed decision process. Decision process consists with three steps. First step is excluding inappropriate location geographically using DEM data including SRTM (Shuttle Radar Topography Mission) terrain data, landslide, land-use, roadway, and forest road data. And the second step of decision process is consideration of the difficulty caused by the natural environmental problem. This step is carried out using ECVAM (Environmental Conservation Value Assessment Map) data. And final step is determination of the most suitable location through the Moving Suitability Identification Method (MSIM) based on the moving potentially estimated wind resources area. Proposed decision process was applied over the Korean Peninsula. Wind resource potential estimated by the first and the second step is cases shows 35.09 GW and 7.17 GW, respectively, and the total evaluated energy from the all proposed step were 0.43 GW and 1.87 GW for the 3 ㎞and 1.5 ㎞geographical grid size, respectively.
        92.
        2014.02 KCI 등재 서비스 종료(열람 제한)
        This paper investigates the characteristics of high PM2.5 episodes occurred at Anmyeondo area in spring time, 2009. The monthly mean PM2.5 concentration during April was the highest in the year and especially, high levels of PM2.5 exceeding standard regulation level were sustained consecutively during 5 to 13 April. To analyze more detailed PM2.5 characteristics, numerical simulations were carried out using CMAQ(Community Multi-scale Air Quality) with IPR(Integrated Process Rate) and DDM-3D(Decoupled Direct Method). PM2.5 level was lower in daytime than that in nighttime due to vigorous vertical mixing during daytime. The chemical composition was showed that ratio of primary ion components such as sulfate(SO4 2-), nitrate(NO3 -) and ammonium(NH4 +) were nearly half of total amount of PM2.5. Aerosol and transport process dominantly contributed to PM2.5 concentration in Anmyeondo area and contribution rate of local emissions was nearly zero since Anmyeondo area has rare anthropogenic PM emission sources. DDM-3D analysis result showed that PM2.5 in Anmyeondo area was influenced by emissions from Shanghai and Shandong region of China.
        93.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        In order to analyze the effect of environmental protection on wind energy dissemination quantitatively, the onshore wind resource potential is estimated using Environmental Conservation Value Assessment Map and Korea Wind Resource Map. The onshore wind resource potential of 11 GW is calculated if wind farm development is prohibited within Class 1 area of Environmental Conservation Value Assessment plus 500 m buffer area. Therefore it is worried that environmental protection would be a practical barrier of accomplishing 4,155 thousand TOE target of wind energy dissemination until 2030.
        94.
        2013.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The effects of gamma irradiation at medium dose levels on commercial starches (corn starch/CS, sweet potatostarch/SS, and potato starch/PS) were investigated in terms of its color and lipid oxidation. The CS, SS, and PS samples were irradiated at 0, 1.5, 3, 4.5 and 6 kGy by a Co-60 gamma irradiator and used for measuring Hunter's colors and TBA value. Irradiation doses applied did not cause apparent changes in Hunter color parameters between the control and irradiated groups. But, the decrease in lightness (L value) for CS and the increase in both redness (a value) for SS and yellowness (b value) for PS were observed, respectively, thereby resulting in slight increase in overall color difference (ΔE) upon irradiation. Browning intensity observed with the naked eye for gelatinized starches by irradiation doses was also gradually increased along with irradiation dose, which was more remarkable in SS. The thiobarbituric acid (TBA) values of samples showed a dose-dependant increase with ≥ 0.9964 of R2 (p<0.05).
        95.
        2012.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Physiological properties of Corni fructus extracts were investigated. The DPPH radical scavenging activity of 90% ethanol extracts had shown 97.20% at 25 mL/g, which was highest in the all extracts. Total polyphenol content of 30% ethanol extracts had shown 140.01mg% at 25 mL/g, which was highest in the all extracts. The polyphenol contents increased as extract concentration rose (25 mL/g>50 mL/g>100 mL/g). Tyrosinase inhibitory effects of all samples were 23.96~88.71%, expecially, the highest at 60% ethanol extracts of 25 mL/g. Nitrite-scavenging abilities under acidic conditions (pH 1.2) were the most effective in all extracts. The results would be useful for understanding of the physiological properties of Corni fructus extracts.
        96.
        2012.02 KCI 등재 서비스 종료(열람 제한)
        The mean wind speed and turbulence intensity profiles in the atmospheric boundary layer were extracted from a LIDAR remote sensing campaign in order to apply for CFD validation. After considering the semi-steady state field data requirements to be used for CFD validation, a neutral atmosphere campaign period, in which the main wind direction and the power-law exponent of the wind profile were constantly maintained, was chosen. The campaign site at the Pohang Accelerator Laboratory, surrounded by 40~50m high hills, with an apartment district spread beyond the hills, is to be classified as a semi-complex terrain. Nevertheless, wind speed profiles measured up to 100m above the ground fitted well into a theoretical-experimental logarithmic-law equation. The LIDAR remote-sensing data of the sub-layer of the atmospheric boundary layer has been proven to be superior to the data obtained by conventional extrapolation of the wind profile with 2 or 3 anemometer measurements.
        97.
        2012.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The anti-obesity activity of the Cucubita moschata Duch. extracts was investigated. The inhibitory effect on triglyceride accumulation was shown in 3T3-L1 preadipocyte. The lipid accumulation of the ethanol extract in 5 mg/mL concentration was shown to be 75.4%, where as that of water extract was shown to be 85.2%. The survival rate of the cell in the viability test was shown to be 86.5% in the 0.5-5 mg/mL concentration. Total polyphenol content was highest in the water extract(46.54 ± 0.02 mg). These results suggest that Cucubita moschata Duch. extracts have a potential as anti-obesity material by reducing the lipid accumulation.
        98.
        2011.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        포도씨에 함유된 항산화 및 아질산염소거성분에 대한 마이크로웨이브 최적 추출조건을 예측하고자, 추출조건(microwave power 0~120 W, 에탄올 농도 0~100%, 추출시간 1~5 min)을 독립변수로 하고 조건별 추출물의 총페놀 함량, 항산화능 및 아질산염소거능을 종속변수로 하여 회귀 분석함으로써 최적 추출조건을 예측하였다. 도출된 회귀식의 는 0.8024-0.9498 범위로 나타났다. 추출물 기능성분들의 최대 예측값과 최적 추출조건은
        99.
        2011.07 KCI 등재 서비스 종료(열람 제한)
        We have established a wind map of Singapore, a city-state characterized its land cover by urban buildings to confirm a possibility of wind farm development. As a simple but useful approximation of urban canopy, a zero-plane displacement concept was employed. The territory is divided into 15 sectors having similar urban building layouts, and zero-plane displacement, equivalent roughness height at each sector was calculated to setup a terrain boundary condition. Annual mean wind speed and mean wind power density map were drawn by a CFD micrositing model, WindSim where Changi International Airport wind data was used as an in-situ measurement. Unfortunately, predicted wind power density does not exceed 80 W/m2 at 50 m above ground level which would not sufficient for wind power generation. However, the established Singapore wind map is expected to be applied for wind environment assessment and urban planning purpose.
        100.
        2011.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        꾸지뽕잎의 물 및 70% 에탄올 추출물에 대한 세포의 독성 및 지방생성에 미치는 영향과 DNJ 함량과 rutin 함량을 측정하였다. Cell viability test에서 꾸지뽕잎 추출물 0.5-5 mg/mL의 농도일 때 물 및 에탄올 추출물 모두 세포의 생장에 영향을 미치지 않는 것으로 나타나 세포에 대한 독성이 없다고 판단되었다. 동일한 농도로 3T3-L1 지방세포의 지방축적에 미치는 영향은 물 및 에탄올 추출물 모두 농도 의존적으로 지방축적
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