• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1267-1271
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• 2001

The objective of this study was to examine the significance of feeding induced hypovolemia (decrease in plasma volume) in controlling the feed intake of goats fed on dry feed. In order to alleviate hypovolemia with feeding, a 2 h intravenous infusion (16-18 ml/min) of artificial saliva or mannitol solution was begun 1 h prior to feeding and continued until 1h after the start of the 2 h feeding period. In comparison with no infusion (NI), cumulative feed intake was increased by 41% with artificial saliva infusion (ASI) and by 45% with mannitol infusion (MI) by the completion of the 2 h feeding period. Both infusion treatments (ASI and MI) were significantly different (p<0.05) from the NI treatment in terms of the cumulative feed intake. The cumulative feed intake between the ASI and MI treatments was not significantly different (p>0.05). No infusion treatment (NI) had the lowest cumulative feed intake (929 g DM), whereas MI had the highest (1345 g DM), after completion of the 2 h feeding period. Generally, infusion treatments also increased the rate of eating at all time points after feeding was commenced. Following the first 30 mins of feeding, the rate of eating decreased sharply, and subsequently declined gradually in all treatments. Compared to the NI, both ASI and MI significantly (p<0.05) decreased thirst level (water intake for 30 mins after the completion of the 2 h feeding period) by approximately 13%. However, the thirst level caused by ASI and MI was not significantly different (p>0.05). Both ASI and MI decreased the plasma concentrations of osmolality and total protein, and hematocrit at 1 h after infusion. The results suggested that the thirst sensation in the brain could be produced by feeding induced hypovolemia. Moreover, the results indicate that hypovolemia is one of the factors controlling the feed intake of goats fed on dry feed.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.91-97
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• 1989

The present experiment was carried out to investigate the effects of heat exposure on water metabolism and the passage of indigestible particles in sheep. Water intake, respiratory rate, rectal temperature and pH of ruminal fluid and urine were significantly higher (P<0.05) in the hot environment ($32\;^{\circ}C$) than in the control environment ($20\;^{\circ}C$). Urine osmolality and blood volume were increased, while glomerular filtration rate was decreased, in the hot environment. The liquid flow rate from reticulo-rumen and the excretion of indigestible particles of specific gravity 0.99 (but not 1.27 or 1.38) were increased in the hot environment. From these findings, it is suggested that an increased water intake evoked by heat exposure might affect the flow rate of digesta in sheep.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.357-365
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• 2004

Effect of artificial circulation on amelioration of water quality in Yeoncho Lake was analyzed using summer data between 1991-2002. Two sites, intake tower area where aeration systems are concentrated in and near the inlet of reservoir were selected for comparison in this study. Summer averages between may and september Showed that aeration system might be beneficial in the improvement of water quality of BOD5, COD, and TN while Chl-a concentration and transparency did show opposite pattems. Wilcoxon's singed rank test for matched pair indicated slight increase of BOD5 and COD concentrations in the vicinity of intake tower while other variables did not show any significant differences from data of inlet of reservoir. During the study, it was found that the following subjects need to be investigated for more detailed analysis. 1) Dynamic pollutant loading from outside and inside the lake, 2) Biological, Chemical and Physical lake data when aeration systems are in and not in operation and 3) Radius of influence of aeration system.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.15-22
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• 2004

Static and dynamic analyses of a very flexible and light riser, for upwelling the deep ocean water, is performed. In this numerical study, an implicit finite difference algorithm is employed for three-dimensional riser equations. Fluid non-linearity and bending stiffness are considered and solved, using the Newton-Raphson iteration. Maintaining the depth of end point of a flexible and light riser is very important for upwelling deep ocean water in a floating type development system. Weight is attached at the end point of the riser in order to maintain its intake depth. It is designed under the strong surface current and the configuration of the rise is predicted. In the dynamic analysis, the tension variation at the top point of the riser is presented. T e results of this study can contribute to the design of the development system in floating type for upwelling deep ocean water.

• 수도
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• v.22 no.4 s.74
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• pp.31-44
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• 1995

• 지반과기술
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• v.2 no.1
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• pp.51-58
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• 2005

• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.383-397
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• 2012

In this study, a System Dynamics (SD) simulation model for the efficient operations of an industrial water supply system was developed by investigating the feedback loop mechanisms involved in the operations of the system. The system was modeled so that as demand is determined the water supply quantity of intake pumping stations and dams are allocated. The main feedback loop showed that many variables such as the combinations of pump operation, unit electric power(kWh/$m^3$), unit electric power costs(won/$m^3$), water level of water way tunnel, suction pressure and discharge of pumping station, and tank and service reservoir water level had causal effects and produced results depending on their causal relationship. The configurations of the model included an intake pumping station model, water way tunnel model, pumping station model (including the tank and service reservoir water level control model), and unit electric power model. The model was verified using the data from the case study industrial water supply system that consisted of a water treatment plant, two pumping stations and four dams with an annual energy costs of 5 billion won. It was shown that the electric power costs could have been saved 7~26% during the past six years if the operations had been based on the findings of this study.

• Journal of Korean Society on Water Environment
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• v.40 no.2
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• pp.89-100
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• 2024

Climate change has a broad impact on the entire water environment, and this impact is growing. Climate adaptation in water supply systems often involves quantity and quality control, but there has been a lack of research examining the impacts of climatic factors on water supply productivity and operation conditions. Therefore, the present study focused on, first, building a database of climatic factors and water purification operating conditions, and then identifying the correlations between factors to reveal their impacts. News big data was analyzed with keywords of climatic factors and water supply systems in either nationwide or region-wide analyses. Metropolitan area exhibited more issues with cold waves whereas there were more issues with drought in the Southern Chungcheong area. A survey was conducted to seek experts' opinions on the climatic impacts leading to these effects. Pre-chlorination due to drought, high-turbidity of intake water due to rainfall, an increase of toxins in intake water due to heat waves, and low water temperature due to cold waves were expected. Pearson correlation analysis was conducted based on meteorological data and the operating data of a water purification plant. Heavy rain resulted in 13 days of high turbidity, and the subsequent low turbidity conditions required 3 days of high coagulant dosage. This insight is expected to help inform the design of operation manuals for waterworks in response to climate change.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.360-366
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• 2008

The spatial and temporal variations of the high turbid water by a single event of heavy rain (total 299.1 mm and daily maximum 99.4 mm) were studied in Andong Reservoir, which has hypolimnetic discharges. Turbid water entered into the reservoir, was isolated from the bottom at the midreservoir and then passed through the metalimnion as an interflow current in the lacustrine zone. Maximum turbidity was 290 NTU at 16 m depth of the midreservoir, but the initial turbidity showed about 10 NTU in the reservoir before the rainfall. Turbid water in the reservoir affected to increase the withdrawal turbidity from the 3rd day after the rainfall, the maximum turbidity was 129 NTU at 5th day after the rainfall. Turbid water that flew towards the downreservoir distributed within 5 m above the outlet gate of the intake tower, showing the maximum turbidity, and that was decreased in its thickness and concentration by discharging through the intake tower. It has taken 38 days until the turbidity in the withdrawal reduced to 30 NTU, and 87 days to reduce the turbidity to the way when it was before the rainfall, with the correlation coefficient of 0.96 and 0.97, respectively. Turbid water was withdrawn from the reservoir by entraining into the intake tower as a form of the interflow, and not be settled down to the bottom of the reservoir. Therefore, we assessed that the depth of the withdrawal was appropriately positioned in Andong Reservoir, so as to withdraw the turbid water effectively from the reservoir.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.765-774
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• 2000

The purpose of this study are to develop a realistic methodology to estimate agricultural water supply for rice paddy fields from reservoirs, pumping stations, intake structures, and tube wells on river basin scale. Agricultural water supply from irrigation reservoirs are estimated using the daily or ten day's storage rate data and DIROMmaily Inigation Reservoir Operation Model) model. Estimation of daily water supply from pumping station are carried out from the annual water use with typical water supply patterns. The daily groundwater withdrawn are investigated from the gross water requirement for rice and the design capacity of tube well. And, the daily intake discharge are estimated the minimum amount from the gross water requirement, stream discharge, and the design capacity. During 1993 to 1997, the annual water supply for irrigation in the Han river basin ranged from 569 to 709 million $\textrm{m}^3/yr$, and the mean was estimated to be 640 million $\textrm{m}^3/yr$.