• 제목, 요약, 키워드: Sediment cell

검색결과 91건 처리시간 0.046초

유역침식 및 퇴적 잠재능 예측모델 개발 (Prediction of Watershed Erosion and Deposition Potentials)

  • 손광익
    • 한국방재학회 논문집
    • /
    • v.7 no.1
    • /
    • pp.67-72
    • /
    • 2007
  • 본 연구에서는 토사에 대한 질량보존의 법칙을 이용하여 자연유역 내 토양의 침식 및 퇴적 잠재능을 산정할 수 있는 모델을 개발하였다. 이 프로그램은 각 셀 별 토사에 대한 질량보존의 법칙을 적용하여 GIS환경하에서 구동 가능하도록 구성되어있으며 셀 별 토사발생량은 RUSLE 공식을 이용하여 산정하였다. 토양의 침식 및 퇴적 잠재능은 토사의 유출량과 유입량의 차에 의해 각 셀이 침식되거나 퇴적된다는 질량보존의 법칙을 이용하여 산정하였다. 질량보존의 법칙을 적용하기 위한 셀 별 토사유출량은 토사발생량과 토사전달률을 곱하여 산정하였으며 이 토사 유출량이 흐름방향 알고리즘에 의해 결정되는 하류 셀의 토사유입량이 된다. 본 연구에서 개발된 모델을 이용하여 국내 소유역에 대해 적용하였으며 그 결과를 실측치와 비교함으로써 모델을 검증하였다.

해양 퇴적토전지의 발전 특성에 대한 연구 (A Study on Electricity Generation of Marine Sediment Cells)

  • 이은미;권성현;이인형;박병기;조대철
    • Journal of Environmental Science International
    • /
    • v.20 no.5
    • /
    • pp.647-653
    • /
    • 2011
  • Sediment cell is renewable energy which produces electric energy using immanent ingredients or reducing power of marine sediment as natural resources. Also the cell has an advantage that environmental pollution can be reduced through conversion of organic and inorganic contaminants into inert matter with generation of the energy. In this paper, we compared characteristics of electricity generation of the two different sediment cells, and investigated the regeneration effect of the sediment cells with manipulation of the sediment such as mixing and re-positioning. The results showed that 14.1 $W/m^2$ of power was obtained with the aluminum electrode, and the mixing of the sediment could increase the power by 4 $W/m^2$ compared to the control. Also, mixing the sediment has kept electricity for 4 weeks at a relatively constant level, which implied 'fuel regeneration effect'. Meanwhile, the sediment cell was proved to be effective in reduction of COD, which was up to 28.6%.

PLHC-1세포주의 Comet assay를 이용한 하천 퇴적토의 생태독성평가 (Studies on Toxicological Evaluation of Freshwater Sediment using a PLHC-1 Cell Comet Assay)

  • 박정아;황인영;백승홍;김영숙
    • 환경생물
    • /
    • v.29 no.1
    • /
    • pp.23-30
    • /
    • 2011
  • In this study, the Comet assay (evaluation of DNA damage) used the fish hepatocellular carinoma cell, PLHC-1, was tried to the sediment extract obtained from freshwater to understand its applicability as a tool for monitoring sediment toxicity. In parallel, induced EROD (7-ethoxyresorufin- O-deethylase) activity and DNA damage (TEM values) in PLHC-1 cells were measured for establishing the tandem endpoints of the PLHC-1cell test to test the ecotoxicity of sediment. Among several study sites in a small river passed through downtown and industrial park area, one of them, site B, showed a higher level of EROD activity and DNA damage than other sites. It indicates that a tandem endpoints of PLHC-1 cells could be useful tools for assessing the toxicity of sediment. The sensitivity of Comet assay with PLHC-1 cells was a little higher than that with a blood cell of frog tadpoles to the solvent extract of sediment. According to the results, a PLHC-1 cell-Comet assay could be used as a useful tool for evaluating ecotoxicity of the freshwater sediment. In addition, more detailed studies are needed to the contaminated site.

Characteristics of Electricity Production by Metallic and Non-metallic Anodes Immersed in Mud Sediment Using Sediment Microbial Fuel Cell

  • Haque, Niamul;Cho, Dae-Chul;Kwon, Sung-Hyun
    • Journal of Environmental Science International
    • /
    • v.23 no.10
    • /
    • pp.1745-1753
    • /
    • 2014
  • Sediment microbial fuel cell (SMFC), equipped with Zn, Al, Cu, Fe or graphite felt (GF) anode and marine sediment, was performed. Graphite felt was used as a common cathode. SMFC was single chambered and did not use any redox mediator. The aim of this work was to find efficient anodic material. Oxidation reduction potential (ORP), cell voltage, current density, power density, pH and chemical oxygen demand (COD) were measured for SMFC's performance.. The order of maximum power density was $913mWm^{-2}$ for Zn, $646mWm^{-2}$ for Fe, $387.8mWm^{-2}$ for Cu, $266mWm^{-2}$ for Al, and $127mWm^{-2}$ for graphite felt (GF). The current density over voltage was found to be strongly correlated with metal electrodes, but the graphite felt electrode, in which relatively weaker electricity was observed because of its bio-oriented mechanism. Metal corrosion reactions and/or a complicated microbial electron transfer mechanism acting around the anodic compartment may facilitate to generate electricity. We presume that more sophisticated selection of anodic material can lead to better performance in SMFC.

Long-term Environmental Changes: Interpretations from a Marine Benthic Ecologist's Perspective (II) -Eutrophication and Substratum Properties

  • Yoo Jae-Won;Hong Jae-Sang;Lee Jae June
    • Fisheries and aquatic sciences
    • /
    • v.2 no.2
    • /
    • pp.210-217
    • /
    • 1999
  • Chemical oxygen demand (COD), phytoplankton cell number and chlorophyll-a concentration (Chl-a), sediment mean grain size and ignition loss were studied to determine their temporal trends in the study area. Historical data of COD, cell number and Chl-a were gathered from the late 1960s or early 1980s to 1997, and trends in temporal domain were obtained from a simple regression. Sediments for grain size and ignition loss (as organic contents in sediments) were sampled from the Chokchon macrotidal flat bimonthly from September 1990 to November 1996, and were analyzed using the decomposition method of time series analysis. In general, the first three data showed increasing trends based on regression analysis. The trends of sediment grain size fluctuated in a neutral pathway while those of ignition loss yielded no increasing pattern. In contrast with the suggestions from Ahn and Choi (1998) who reported a coarsening variation in sediment grain size to be a cause of the directional and remarkable changes of macrofaunal communities in this area, we could not find such a corresponding variation pattern from our samples. In diagnosing eutrophication, a paradoxical phenomenon was encountered between the trends in water column (COD, cell number and Chl-a) and sediment (ignition loss) data. In this paper, we inferred the possible processes that produce the discrepancy. Some explanations and biological responses to eutrophication were predicted and discussed.

  • PDF

복합 토지이용 특성의 농촌유역에 대한 농업비점원오염모형의 적용 (Applications of AGNPS model with rural watersheds having complex land use characteristics)

  • 조재필;박승우;강문성
    • 한국농공학회:학술대회논문집
    • /
    • /
    • pp.353-358
    • /
    • 1998
  • GRASS-AGNPS model integrated with GIS was applied to rural watersheds having complex land use characteristics and evaluated for its applicability through calibration using observed data. The analyses of raster encoding accuracy and model behavior to runoff, sediment yields and nutrient loads for different cell-size showed that 150 m cell size indicated reasonable applicability of the model. Simulated runoff was in a good agreement with the observed data and simulated peak runoff rate was larger than the observed data. The sediment yield simulated by modified AGNPS model using irregular cell for forest area were less than that of the regular cell method. In predicting sediment yields, the result showed a different trend at each representative rural watershed. Nutrient loads simulated by the model were significantly different from the observed data.

  • PDF

현미경검사를 위한 요침사 표본제작에 따른 차이 연구 (Study on the Difference of Urine Sediment Preparation for Microscopic Examination)

  • 이혁재;박철;서민영
    • 대한임상검사과학회지
    • /
    • v.49 no.4
    • /
    • pp.366-373
    • /
    • 2017
  • 소변검사는 다른 검사에 비해 쉽고 간편하면서도 환자에게 부담이 없는 검사로 신장 및 요로계 질환의 진단, 치료 및 예후 결정에 중요한 정보를 제공한다. 요 침전물은 일반적으로 원심분리된 소변을 검사자가 현미경을 통한 검경에 의해 이루어진다. 대한임상검사정도관리협회에서 제안한 가이드라인과 실제로 의료기관에서 시행되고 있는 내용이 다르고 임상병리학을 전공하는 학생들이 사용하고 있는 서적에 제시된 내용도 서로 차이가 있었다. 따라서 요 침전물 표본제작에 따른 차이가 검사결과에 영향을 주는지 확인하기 위하여. 요시험지봉검사에서 잠혈반응과 백혈구 에스터라아제 검사 결과 양성으로 확인된 검체를 무작위로 선별하여 현미경적 검사를 시행하였다. 요 침전물 표본제작 차이는 요 농축 배수에 영향을 주어 cell grade나 시야 당 평균 세포 수 결과에 영향을 미쳤다. 침전물의 농도를 결정짓는 첫 번째 요소는 원심력이다. 그러나 많은 의료기관에서 원심분리기 반경을 고려하지 않는 채 1,500 rpm을 사용하고 있었으며 이는 400 G라는 정확한 원심력을 얻을 수 없었다. 결과적으로 요 농축에 있어 차이가 발생하여 결과에도 영향을 미쳤다. 두 번째 요소는 요 침사물의 양이다. 제거하고 남은 요의 상청액의 양은 요 침사물의 농축 계수에 영향을 주어 다른 결과를 초래하였다. 뿐만 아니라 피펫을 사용하여 제시된 정확한 용량을 취하지 않고 대략적으로 한 방울을 떨어뜨린 후 경검했을 때도 결과에 영향을 주었다. 따라서 일관성 있고 보다 정확한 검사결과를 위해 반드시 표본제작 과정이 표준화가 되어야 할 것이다.

MFC의 금속 및 탄소전극에 의한 전기생산 특성과 오염저감 효과 (Electricity Generation and De-contamination Effect for Characteristic Electrode Material in a Microbial Fuel Cell System Using Bay Sediment)

  • 권성현;송형진;이은미;조대철;이인형
    • Journal of Environmental Science International
    • /
    • v.19 no.8
    • /
    • pp.951-960
    • /
    • 2010
  • Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. $0.57\;W/m^2$ Al/Graphite. Meanwhile, graphite-only electrodes produced max. $0.11\;W/m^2$ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was $0.64\;W/m^2$. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5~36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.

골재채취가 세균군집구조에 미치는 영향 (Effects of Sediment Harvesting on Bacterial Community Structure)

  • 박지은;이영옥
    • 환경생물
    • /
    • v.24 no.2
    • /
    • pp.172-178
    • /
    • 2006
  • 골재채취가 수층의 세균군집구조에 미치는 영향을 알아보기 위해 낙동강 중류, 골재채취가 이루어 지지 않은 수역인 구미대교와 장기간에 걸쳐 연속적으로 골재채취가 행해지는 지역인 성주군 소학리 (성주대교 인근)에서 $\alpha\;\beta\;\gamma-subclass$ proteobacteria, Cytophaga-Flavobacterium (CF) group 세균군과 황산염화원세균을 FISH법으로 정량분석하였다. 아울러 수온, pH, EC, 엽록소-$\alpha$ 양 등의 이화학적인 환경요인도 측정하였다. DAPI로 염색된 세균수로 측정한 총세균수의 경우, 두 정점간의 괄목할 만한 양적인 차이는 없었으나 그 시간차에 따른 변동이 골재채취 수역에서 더욱 심했다. 또한 높은 엽록소-$\alpha$ 양을 나타낸 골재채취 수역에서 검출한 CF group 세균군과 황산염환원세균이 총세균수에서 차지하는 비율이 비골재채취 수역에 비해 높았다. 이같은 결과는 저니질이 수층으로 재유입되었기 때문으로 판단된다. 그러나 본 연구에서 검출한 세균군이 총세균수에서 차지하는 비율을 합하면 그 비율은 골재채취 수역보다 비골재채취 수역에서 더 높았다. FISH법에 의한 세균의 검출가능성이 해당세균의 물질대사능과 연관이 있으므로 골재채취 수역에서의 낮은 세균 검출율은 골재채취가 세균의 물질순환에서의 역기능을 초래하고 이는 또한 연차적으로 그들의 먹이연쇄에 부정적인 영향을 미칠 가능성을 시사하는 것이다.