• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1576-1589
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• 2006

Most of surface water ways in Egypt suffer from the infestation of aquatic weeds especially submerged ones which cause lots of problems for the open channels and the water structures such as increasing water losses, obstructing the water flow, and reducing the efficiency of the water structures. Accurate simulation of the water flow behavior in such channels is very essential for water distribution decision makers. Artificial Neural Network (ANN) has been widely utilized in the past ten years in civil engineering applications for the simulation and prediction of the different physical phenomena and has proven its capabilities in the different fields. The present study aims towards introducing the use of ANN technique to model and predict the impact of the existence of submerged aquatic weeds on the hydraulic performance of open channels. Specifically the current paper investigates utilizing the ANN technique in developing a simulation and prediction model for the flow behavior in an open channel experiment that simulates the existence of submerged weeds as branched flexible elements. This experiment was considered as an example for implementing the same methodology and technique in a real open channel system. The results of current manuscript showed that ANN technique was very successful in simulating the flow behavior of the pre-mentioned open channel experiment with the existence of the submerged weeds. In addition, the developed ANN models were capable of predicting the open channel flow behavior in all the submerged weeds' cases that were considered in the ANN development process.

• Water Engineering Research
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• v.3 no.4
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• pp.259-267
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• 2002

South Africa has developed a policy and law that calls and provides for the equitable and sustainable use of water resources. Sustainable resource use is dependent on effective resource protection. Rivers are the most important freshwater resources in the country, and there is a focus on developing and applying methods to quantify what rivers need in terms of flow and water quality. These quantified and descriptive objectives are then related to specified levels of ecological health in a classification system. This paper provides an overview of an integrated and systematic methodology, where, fer each river, and each river reach, the natural condition and the present ecological condition are described, and a level/class of ecosystem health is selected. The class will define long term management goals. This procedure requires each ecosystem component to be quantified, starting with the abiotic template. A modified flow regime is modelled for each ecosystem health class, and the resultant fluvial geomorphology and hydraulic habitats are described. Then the water chemistry is described, and the water quality changes that are likely to occur as a consequence of altered flows are predicted. Finally, the responses to the stress imposed on the biota (fish, invertebrates and vegetation) by modified flow and water quality are predicted. All of the predicted responses are translated into descriptive and/or quantitative management objectives. The paper concludes with the recognition of active method development, and the enormous challenge of applying the methods, implementing the law, and achieving river protection and sustainable resource-use.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.3
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• pp.141-146
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• 2016

The AMR(automatic meter reading) system has been increasingly and widely used for its efficient and intelligent management, which is a technology that automatically collects consumption data from a water meter or energy metering device. The digital meter instead of the mechanical meter should be used in the system. Up to now, various types of sensor to measure the water flow rate have been used in the digital water meter, for example, reed switch, photo IR approximate sensor, ultrasonic sensor, electromagnetic sensor, etc. In this paper, a new sensing technology, where a variable capacitor and digital circuit were used for sensing the water flow rate, was proposed. The circuit was designed and verified by Pspice simulation. And a PCB board for the circuit was fabricated. After then, a prototype of digital water meter using a variable capacitor to measure the water flow rate was fabricated. The function tests of the fabricated digital water meter were performed, and it was found that the meter worked properly. Since the new technology has much better properties in terms of cost and power consumption compared to conventional technologies, it should be one of the major digital water meter technologies in the future.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.69-77
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• 1996

To evaluate the change of the groundwater flow and the water table response resulting from urbanization, two cases of the transient three-dimensional numerical simulations were performed. Variations of the groundwater flow system caused by withdrawals were analyzed. Two cases of infiltration rates were applied in this study to verify the water table changes. One is the rate under the circumstance during 1994 and the other is the revised rate. The numerical results from this study indicated that groundwater flow was influenced by human impacts. Groundwater flow has been concentrated to Taegu Textile Complex area where had large amount of pumping. Water table so far decreased -2.76m a year due to withdrawals. Water tables of many points were increased more than 30cm when the surface was reformed by infiltrating the rainfall. It was appeared that the improvement of surface to recharge the precipitation was very important to preserve and manage for the groundwater.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.67-74
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• 2008

The regional-scale transient groundwater-river interaction model is developed to gain a better understanding of the regional-scale relationships and interactions between groundwater and river system and quantify the residual river flow after groundwater abstraction from the aquifers with climate variability in the Waimea Plains, New Zealand. The effect of groundwater abstraction and climate variability on river flows is evaluated by calculating river flows at the downstream area for three different drought years (a 1 in 10 drought year, 1 in 20 drought year, and 1 in 24 drought year) and an average year with metered water abstraction data. The effect of future water demand (50 year projection) on river flows is also evaluated. A significant increase in the occurrence of zero flow, or very low flow of 100 L/sec at the downstream area is predicted due to large groundwater abstraction increase with climate variability. Modeling results shows the necessity of establishing dynamic cutback scenarios of water usage to users over the period of drought conditions considering different climate variability from current allocation limit to reduce the occurrence of low flow conditions at the downstream area.

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.20-27
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• 2000

The grid-based KIneMatic wave STOrm Runoff Model(Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of saturated overland flow, subsurface flow and stream flow was evaluated at two watersheds. this model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. the model programmed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS (Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.20-27
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• 2000

The grid-based KlneMatic wave STOrm Runoff Modei (Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of saturated overland flow, subsurface flow and stream flow was evaluated at two watersheds. This model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. The model programed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS (Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.61-65
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• 2014

Pressure distribution around rotating impeller blades in centrifugal pump has been main issue for design of efficient and high performance automotive water pump. In addition, pressure losses of inlet water pipes should be considered to reduce additional pressure drop and design high performance engine cooling system. In this paper, pressure distribution inside water pump and pressure drop between inlet and outlet of water pump are investigated numerically to design plastic water pump for clean diesel engine application. And the inlet geometry of water pump was considered to analysis the effect of inlet water pipe geometry on pressure distribution around impeller blades and outlet pressure. The prediction results are compared with experimental data to validate and determine optimal operation condition without water pump cavitation. Major design parameters such as blade angle, volute geometry, system pressure, and coolant flow rate are considered to confirm applying possibility of plastic blades to the clean diesel engine.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1304-1310
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• 2015

In remote islands, due to expense of existing generation systems, installation of photovoltaic cells (PVs) and wind turbines has a chance of reducing generation costs. However, in island power systems, even short-term power fluctuations change the frequency of grids because of their small inertia constant. In order to compensate power fluctuations, the authors proposed the power consumption control of pumps which send water to tanks. The power control doesn’t affect water users’ convenience as long as tanks hold water. Based on experimental characteristics of a pump system, this paper shows methods to determine reference power consumption of the system with compensation for short-term PV fluctuations while satisfying water demand. One method uses a PI controller and the other method calculates reference power consumption from water flow reference. Simulations with a PV and a pump system are carried out to find optimum parameters and to compare the methods. Results show that both PI control method and water flow calculation method are useful for satisfying the water demand constraint. The water demand constraint has a little impact to suppression of the short-term power fluctuation in this condition.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.759-764
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• 2005

In this paper, numerical analysis of hydrogen recycle system has been conducted in order to enhance the efficiency of automotive fuel cell. Generally, the excess hydrogen is provided in the automotive fuel cell. Since the non-reaction hydrogen reduces automotive fuel cell efficiency, reuse of the non-reaction hydrogen can be helpful to improve the fuel cell performance. In case of PEM FC, the water vapor is provided to hydrogen from the cathode so that the mixture experiences phase change depending on the changes of pressure and temperature. The internal flow of the mixture in the hydrogen recirculation system of fuel cell was investigated for real flow conditions. The variation of performance, properties and mass fractions of mixture, hydrogen and water-vapor were investigated. This study was performed based on 80KW level automotive fuel cell's recycling system.