• Title/Summary/Keyword: Tides

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Histological Effect of Sodium Hypochlorite (NaOCl), Exposed at Red Tide-killing Concentrations, in Rockfish and Little Neck Clam (적조생물구제농도의 Sodium Hypochlorite(NaOCl)의 노출에 따른 조피볼락 및 바지락의 조직학적 영향)

  • 한조희;김영석;허민도;정해진;박관하
    • Environmental Analysis Health and Toxicology
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    • v.16 no.2
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    • pp.67-74
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    • 2001
  • In a previous study by Kim et al. (2000), sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safely of the chemical in practical use, effect of NaOCl, at concentrations required for algicidal activity, on the histology of rockfish and little neck clam was examined. When the animals were exposed to NaOCl at concentrations of 0.5 or 2ppm for 1 hr, there was no exposure-associated histological change in either animal. As the experimental exposure condition was set in consideration of the use, our results provide safety information necessary for practical application to marine fields.

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S/W DEVELOPMENT OF HIGH PRECESION EPHEMERIS(I) (고정도 천체력 S/W 개발(I))

  • 안영숙;신종섭;박필호;박온광;이정숙
    • Journal of Astronomy and Space Sciences
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    • v.10 no.2
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    • pp.152-162
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    • 1993
  • We developed the S/W which calculate the Planetary and the Moon ephemerides. The ephemeris of the Solar system objects was obtained from a simultaneous numerical integration of the equations of motion for the nine planets and the Moon. The mathematical model includes contributions from (1) point-mass interactions (2) figure effect (3) earth tides (4) the orientations of the Earth and the Moon. The calculated ephemerides are compared with DE200 data produced by JPL (Jet Propulsion Laboratory).

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Tidal behavior changes in Mangyeong reservoir area with permitting sea-water intrusion through the sluice gate (만경수역 해수 유통시 조석환경변화 고찰)

  • Kwun, Soon-Kuk;Park, Yeong-Wook
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2001.10a
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    • pp.21-24
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    • 2001
  • As one of the phil-environmental alternative plan of Saemankeum project, gradual development is recommended. The procedure of the Saemankeum project start with the completion of 32 km long sea-dikes which contains two discharge gates until the year 2004. Second step is pre-development of Mangyoung area permitting temporary intrusion of sea water, i.e. tides, by the opening of discharge gate until the environmental evaluation on the water quality of this area secures permanent meet to government's water quality standard. Therefore this study is to predict the future condition of this tidal flat with the point of view tidal environments, salt, water quality, soil mechanics, etc. of Mangyoung area when the sea water still passed in the inland reservoir through the discharge gate.

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Study on the Water and Material Exchange in Deukryang Bay 1. Volume Transport and Turnover Time of Sea Water (득량만의 해수 교환 및 물질 순환에 관한 연구 1 . 해수의 수송량 및 교환 시간)

  • 조규대;이충일
    • Journal of Environmental Science International
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    • v.7 no.3
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    • pp.311-320
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    • 1998
  • The volume transport and turnover time of the Deukryang Bay. located at the southern area of Korea, were calculated based on the current meter(RCM-7,ACM 16M) data observed at the three gateways of the tegrating observed data and then averaging on time. dangdo and Kogumdo. The total water volume transports through three entrances of the bay in May and October were $3.9{\times}10-2Sv, 3.4{\times}10^{-2}Sv(1Sv=10^6m^3s^{-1}$) and turnover time were 0.97day, 1.12day, respectively. Semidiurnal tides were predominant (70~85%). The water volume transports by residual currents were 2~4% of total water volume transports . The average fraction of fresh water calculated by tidal prism method using salinity difference between inflow current and outflow current through three entrances In Deukryang Bay was about 0.06% of total volume and the flushing time of fresh water was estimated as 0.97day.

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Interference Effects on the Performance of Multi-arrayed HAT TCP Devices (복합배치 수평축 조류발전 로터의 간섭성능 고찰)

  • Jo, Chul-Hee;Lee, Kang-Hee;Yim, Jin-Young;Rho, Yu-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.2
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    • pp.36-40
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    • 2010
  • Tidal current power system is the energy converter which converts the kinetic energy of tidal stream into electric energy. The performance of the rotor which initially converts the energy is determined by various design factors and it should be optimized by the ocean environment of the field. Flow direction changes due to rise and fall of the tides, but horizontal axis turbine is very sensitive to direction of flow. To investigate the rotor performance considering the interaction problems with incidence angle of flow, series of experiments have been conducted. The results and findings are summarized in the paper.

동남해안지역의 피압단열 대수층에서 조석 분석법을 이용한 수리상수 추정

  • 심병완;정상용;성익환;이병대;조병욱
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.497-500
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    • 2003
  • If ground water levels of a confined fractured rock aquifer fluctuate with sea tides, individual values of hydrogeologic parameters can be determined. Tidal efficiency and time lag are first calculated from the water level data recorded at an observation device situated inland from the sea. The tidal efficiency factor of the aquifer at the seacoast is then determined from the observation in monitoring wells and used to calculate storage coefficient. Tidal efficiency factor and the tidal time lag are utilized to calculate storage coefficient and the results are compared. This method is tested in the southeastern coastal area of Busan, Korea. This is a simple and inexpensive way to test confined aquifer but the analysis should be performed according to the coastal environment.

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How Much Power can be Obtained from the Tides?

  • Garrett, Chris
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.74-79
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    • 2006
  • General formula are presented for the maximum power available from the tidal head in a closed basin and from the tidal currents in a channel connecting two large bodies of water. In the latter case, the available energy cannot be estimated from the kinetic energy flux in the undisturbed state, but can be obtained from knowledge of the tidal head between the ends of the channel and the maximum volume flux in the undisturbed state. The results are supported by detailed calculations for Johnstone Strait, British Columbia, using a two-dimensional finite element model. The model also allows an extension to the case of multiple channels. More work is needed to allow for partial tidal fences which do not occupy the whole cross-section of a channel.

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Numerical Simulation of Tidal Current Patterns for Estuary Morphological Changes using Simple 2D Model (단순모델을 이용한 하구역 지형변화와 해수유동장 변화 수치모의)

  • Lee, Young-Bok;Yoon, Han-Sam;Ryu, Cheong-Ro
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.445-448
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    • 2006
  • 본 연구는 기초적인 연구로 낙동강 하구역을 단순 사각형 만의 형상을 가진 지형으로 설정하고 내부 지형의 변화(수심 및 사주 면적)에 따른 해수유동장을 해수유동 수심적분모델로 구축하여 계산하였다. 계산된 유속장 결과를 바탕으로 내부 지형의 대표단면에서의 단면유량플럭스를 계산하여 상호 비교함으로써 하구역내 사주의 생성 및 발달(내부 지형 용적 변화)에 따른 하구역 입구부에서의 해수용적 변화(순환)의 정도를 평가하고자 하였다.

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Contribution and Future Direction in the Study of Aquacultural Oceanography in Jinhae Bay, Korea (진해만의 양식해양학적 연구의 업적과 미내의 과제)

  • CHO Chang-Hwan
    • Journal of Aquaculture
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    • v.4 no.2
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    • pp.129-136
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    • 1991
  • This is a review of the studies on aquaculture and its environments in Jinhae Bay, one of the most productive areas in the south coastal waters in Korea, carried out since 1960's. It's content consists of describing the outlines of, (1) a brief history of shellfish culture development and the study of oceanic environments relating to the aquaculture, (2) the oceanographic studies on the eutrophication, red tides, and the mass mortality of shellfish due to pollution and (3) the studies on forecasting aquaculture and oceanographic conditions, and on the direction of aquacultural oceanographic studies in the near future.

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Ocean Current Power Generation using sea water discharged from Turbine Generator and Gate Channel of Tidal Power Plant (조력발전소의 수차발전기 및 수문도수로 방출수를 이용한 해류발전)

  • Jang, Kyung-Soo;Lee, Jung-Eun
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.180-183
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    • 2008
  • This paper is about the ocean current power generation using sea water incoming into the lake surrounded by barrages and sea water discharged from a dam made of artificial structures. In operation of a tidal power plant, the sea water discharged from a turbine structure and a gate structure of a tidal power plant is faster than the tidal current caused by tides in nature and has better characteristics than that to run ocean current turbines. It is shown that the sea water discharged after generating electricity through a turbine generator of a tidal power plant and the sea water discharged from a gate structure of a tidal dam still have kinetic energy high enough to run an ocean current turbine and produce valuable electricity.

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