• Title/Summary/Keyword: Water relations

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A Study of Reliability Index Correlation Analysis in Reservoir Water-supply (저수지 용수공급량에 따른 신뢰도 지표인자의 상관관계 해석)

  • Park Ki-Bum
    • Journal of Environmental Science International
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    • v.14 no.3
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    • pp.289-296
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    • 2005
  • In this study aims is water supply criteria relations for evaluating the possible performance of water resources systems. These measures describe how likely a systems is to fail(reliability), how quickly it recovers from failure(resiliency), and how severe the consequences of failure may be(vulnerability). The performance of a criteria evaluating with a variety of operating policies illustrates their use. As a result study frequency reliability and quantitative reliability is linear relations and quantitative reliability is high reliability for equality water supply policy. As reliability and vulnerability are in inverse proportion to each other. Therefore these criteria relation analysis can be for Imha dam to variety water supply policy.

Determination of Stage-discharge Relations by Hydraulic Channel Routing and Stage Measurement (수위관측과 수리학적 하도추적에 의한 수위-유량 관계식작성)

  • Lee, Sang-Ho
    • Journal of Korea Water Resources Association
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    • v.34 no.5
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    • pp.551-560
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    • 2001
  • The research estimated the roughness coefficients for the reach of Hwawon-Goryeonggyo-Hyeongpung stage stations in the Nakdong River through hydraulic channel routing. The data needed were only stage data from the three stations and river cross section data. Stage-discharge relations were determined from the computed discharges by the channel routing. They are better than the previous stage-discharge relations from direct measurements. Discharge computation errors from stage errors were analyzed and a simple method was suggested to limt reach lengths from prohibiting large errors from lateral inflows.

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Diurnal changes of Tissue Water Relations in Two Allopatric Tree Species (이소적 두 수종의 수분관계 일변화)

  • Park, Yong-Mok
    • The Korean Journal of Ecology
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    • v.19 no.5
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    • pp.453-463
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    • 1996
  • Diurnal changes of microclimatic conditions and tissue water relations were measured at two sites where Carpinus laxiflora and C. cordata were allopatrically distributed. The microclimatic conditions at a site where C. laxiflora was distributed produced severe water stress condition during summer months. Daily maximum temperature reached $30.4^\circC$ and the highest vapor pressure deficit was 1.31 KPa when 13 rainless days were continued. During this period soil water content decreased to below the field capacity even at a depth of 20 cm and xylem pressure potential also decreased to ­2.04 MPa. However, turgor potential was maintained more than 0.4 MPa. Patterns of stomatal conductance were changed with evaporative demand and soil water availability. On the other hand, microclimatic conditions at a site where C. cordata was distributed were moderate water strees condition compared with those at a site C. laxiflora was distributed. Though soil water content was maintained above field capacity C. cordata showed a remarkable decrease in turgor potential and stomatal conductance throughout the experiment. These results indicate that there is a difference in habitat characteristics between the two species and C. laxiflora is more resistant than C. cordata to water stress.

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Ecophysiological Interpretations on the Water Relations Parameters of Trees. -I. The Diagnosis of Tolerant Tree to Drought by the Pressure Chamber Technique (수목(樹木)의 수분특성(水分特性)에 관(関)한 생리(生理)·생태학적(生態学的) 해석(解析)(I) - Pressure Chamber Technique에 의한 내건성(耐乾性) 수종(樹種)의 진단(診㫁) -)

  • Han, Sang Sup;Kim, Kwang Ryun
    • Journal of Korean Society of Forest Science
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    • v.50 no.1
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    • pp.25-28
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    • 1980
  • The purpose of the this study was to compare the torlent tree to drought among the Pinus koraiensis, Abies holophylla, and Ginkgo biloba. The water relations parameters of leafy shoots were measured by the Pressure chamber technique from August 10 to September 4 in 1980. On the water relations parameters such as original osmotic pressure(${\pi}_0$), osmotic pressure(${\pi}_p$) and relative water content (RWC) at incipient plasmolysis, and Vp/Vo ratio of the volume of osmotic water (Vp) at incipient plasmolysis to total symplasmic water (Vo) basis, the Abies holophylla shoots showed ontogenetically a superior osmoregulation which are closely associated with drought resistance compared with Pinus koraiensis, and the Ginkgo biloba shoots showed the heighest among these three species.

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Effects of Light, Temperature, Water Changes on Physiological Responses of Kalopanax pictus Leaves(IV) - Characteristics of Leaf Water Relations Obtained from P-V Curve - (광, 온도, 수분 변화에 따른 음나무 엽의 생리반응(IV) - P-V 곡선에 의한 잎의 수분특성 -)

  • Han, Sang-Sup;Jeon, Doo-Sik;Sim, Joo-Suk;Jeon, Seong-Ryeol
    • Journal of Forest and Environmental Science
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    • v.22 no.1
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    • pp.71-75
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    • 2006
  • Water relations of Kalopanax pictus leaves obtained from the P-V curve. In the upper leaves of Kalopanax pictus seedlings, the original osmotic pressure at maximum turgor was -1.44 MPa, and the osmotic pressure at incipient plasmolysis point was -1.84 MPa, and the relative water content at incipient plasmolysis point was 78.2%.

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Non-equilibrium Molecular Dynamics Simulations of Thermal Transport Coefficients of Liquid Water

  • Song Hi Lee;Gyeong Keun Moon;Sang Gu Choi
    • Bulletin of the Korean Chemical Society
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    • v.12 no.3
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    • pp.315-322
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    • 1991
  • In a recent $paper^1$ we reported equilibrium (EMD) and non-equilibrium (NEMD) molecular dynamics simulations of liquid argon using the Green-Kubo relations and NEMD algorithms to calculate the thermal transport coefficients-the self-diffusion coefficient, shear viscosity, and thermal conductivity. The overall agreement with experimental data is quite good. In this paper the same technique is applied to calculate the thermal transport coefficients of liquid water at 298.15 K and 1 atm using TIP4P model for the interaction between water molecules. The EMD results show difficulty to apply the Green-Kubo relations since the time-correlation functions of liquid water are oscillating and not decaying rapidly enough except the velocity auto-correlation function. The NEMD results are found to be within approximately ${\pm}$30-40% error bars, which makes it possible to apply the NEMD technique to other molecular liquids.

Morphometric relations and diet compositions of Nile tilapia Oreochromis niloticus (Linn. 1758) in Lake Tana Gorgora gulf, Ethiopia

  • Flipos Engdaw
    • Fisheries and Aquatic Sciences
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    • v.26 no.3
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    • pp.169-180
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    • 2023
  • Oreochromis niloticus is the most ecologically and economically important fish in tropical and sub-tropical aquatic systems. Recently, due to sever anthropogenic stressors, hydrological variations and infestations of invasive alien species in Ethiopian water bodies, fish community structure and ecosystem of Lake Tana is changing alarmingly. So far, there is paucity of information on the morphometric relations and diet composition of O. niloticus in Lake Tana, gulf of Gorgora. A total of 309 fish samples were collected and their total length (TL), standard length (SL) and total weight (TW) were measured to determine morphometric relations; and gut contents were examined to identify most important food item in the diet of the fish. Results indicated that, the relation between TL and SL was significant (p < 0.001) and linear (SL = 0.942TL-2.41) while the relation between TL and TW was curvilinear (TW = 0.014 TL2.8) indicating allometric growth. Among the total guts scrutinized, 53 (17.3%) of them were empty and the remaining 256 (82.7%) were non-empty. Phytoplankton constituted the largest bulk and occurred in 77% of the guts examined and volumetrically accounted 44.3%. Detritus and zooplankton had an intermediate importance by occurring 60.2% and 63.3% of all guts scrutinized and constituted about 25.6% and 15.5% of the total volume respectively. Contributions of macrophytes, insects, nematodes and unidentified food items were relatively low in their importance. Ontogenetic dietary shift was observed in the diet indicating an omnivorous feeding habit of the adult fish.