• Journal of Appropriate Technology
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• v.5 no.1
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.313-324
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• 2011

Several complaints from consumers on red or turbid waters were often filed at the same places although various efforts were made to improve water quality in the drinking water plant. The red water problems were occurred due to corrosion of main water pipe, especially at extremity. The low concentrations of chlorine indicating poor water quality were detected at the problematic location. To solve the poor water quality at the extremity, flushing techniques, i.e., conventional flushing, unidirectional flushing, and continuous flushing, were recently practiced. In this study, effects of conventional flushing on water qualities were examined by comparing turbidity and residual chlorine before and after flushing. In addition, more detailed analyses on water qualities at the tap water were conducted to learn a reduction pattern during flushing. Five items from geographic information system of water distribution were used to obtain a relationship with water quality, washing duration or amounts of washing water. The flushing was effective to meet the National Drinking Water Quality Standard with simple and relatively short time operation. The key operational parameter in flushing was amounts of washing water which should be estimated based on water quality of the consumer's tap water. The positive relationship between the residual chlorine and pipe length implied that detention time in the pipeline was the main cause of the complaints. More experiments on effectiveness of flushing are needed to determine reasonable strategies of flushing.

• Journal of Environmental Impact Assessment
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• v.28 no.4
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• pp.373-386
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• 2019

In The study, is to investigate the spatial characteristics of the Miho stream, which is the main tributary of the Geum River system, and to identify the main factors influencing the water quality using water quality analysis and multivariate analysis. The survey subjects were selected as 7 main sites in the Miho stream water system, From 2012 to 2017, 16 items including weather temperature and weather data were used for multivariate analysis. As a result of the water quality analysis, the average concentration of BOD and COD for 6 years was 3grade (normal) compared with the water quality environmental standard (river) of conditions. The concentrations of nitrogen and phosphorus were highest at th upstream site, then decreased and then increased again by the hydrogeological and geomorphological effect. Cluster analysis of spatial and water quality characteristics, it was evaluated as three clusters and the pollution sources is the greatest impact. As a result of principal component analysis and factor analysis on each cluster and mainstream, three to four major components were extracted. Main stream and the Cluster 1, Cluster 3 first principal factor included nitrogen and seasonal factors,first factor of Cluster 2 included nitrogen and water temperature. Nitrogen is the principal factor which affects water quality in Miho stream.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.505-505
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• 2022

This study shows the first output of the three-year project (2021-2023) to develop a Smart Water City (SWC) Global Standard and Certification Scheme ley by K-water, International Water Resources Association (IWRA) and Asia Water Council (AWC). There are three major parts in the first year. In Part 1, it investigates the essential features of cities today and details the water challenges currently faced and likely to be confronted in the future. It also investigates the functions that water fulfills in the urban environment, and how ICTs can contribute to improving those functions by each Urban Water Cycle. A definition of a Smart Water City is proposed following a discussion on the meaning of "smart development". This part of the report also presents different city cases from countries around the world to illustrate the urban water challenges and the technological and non-technological solutions that cities have put in place, including national and/or local policies and strategies. In Part 2, it defines what global standards indicators and certification schemes are and identifies their characteristics. Especially, it analyses in detail eight relevant standards and certification schemes measuring sustainable development and/or water resources management in urban settings. Standards elaborated by international organizations are distinguished from those developed by the private sector, non-governmental organizations, and by academia. Finally, this study suggests the right direction to develop SWC global standard frameworks and certification schemes. And then, it shows the main tasks for the Stage 2 (second year) project. Basically, the framework for a future SWC standard (consisting three main pillars: Technical, Governance and Prospective pillars) will be fully defined in Stage 2.

• Journal of Environmental Health Sciences
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• v.2 no.1
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• pp.25-28
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• 1975

The main purpose of the aeration units in activated sludge process is to enable micro-organisms to metabolize the constituents of the waste effectively by supplying sufficient oxygen for their respiration. Normally, aeration is achieved by bringing the mixture of waste and sludge into intimate contact with air. The main type of aeration unit is diffused air unit in which air is injected into the liquid in the form of bubbles. The object of these laboratory studies is to compare the performance of three laboratory scale aeration systems at various depths of submergence, aerating water with and without the addition of a surface active agent.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.763-768
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• 2009

Ozone is a strong oxidant and a powerful disinfectant. In general, it has been used in drinking water treatment during last 100years. Ozone dissolution features are defined by the two categories of ozone contactors, bubble-diffuser and sidestream ozone contactor. Currently, sidestream-injection systems are gaining in popularity but operating cost might be slightly higher. Sidestream ozone system dissolve ozone into a sidestream flow via an injection setup or in the main process flow stream in some sidestream arrangements. The sidestream flow is subsequently mixed with the main process flow stream, which is directed to a reation tank or pipeline for oxidation and disinfection reactions. The purpose of this study is to suggest optimal operating pressure, to figure out the static-mixer effect and to understand the microbubble characteristics of ozone to improve dissolution efficiency.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.341-352
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• 1990

The purpose of this research is to develop the design/control method that can be used for the improvement of harbour tranquility and water quality of fishing ports. For this end, firstly, the hydraulic environmental characteristics of fishing ports in the coastal waters of the Korean Peninsula are analysed and discussed combined with disasters of facilities and vessels in the ports. Secondly the problems of water quality control is pointed out considered with the improvement measures of harbour tranquility such as the methods of lengthen of main breakwaters and construction of wave absorbing structures. Finally, the control characteristics of composite functions of water quality and tranquility of fishing port are discussed and the improved control method si proposed using the experimental results for the various measures. The proposed measure is proved to be a applicable method to improve these two main functions on the design of fishing port.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.170.4-170
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• 2001

Safety and confidence of the communications network is the main purpose for the unmanned control systems, in terms of appling a satellite communications network to the water treatment and supply plant communication system. Since the unmanned control systems were applied in the industrial site, the lack of confidence on the communications network has been presented continuously as a main problem for the unmanned and automation systems. Therefore, satellite communications network was presented as one of the methods to solve this problem, supporting the wire used telecommunication. In addition to the safety of a communications network, there is the retrenchment of expenditure. This dual communications network has ...

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.11a
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• pp.173-174
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• 2004

The Great Wall is an element in University which stand outs as a landmark. The Great Wall is located in front of the grand staircases of the gymnasium in the main gate area. Falling water and Lights shows a spectacle panorama in various point of view. Water falls down the top of the grand staircases and the front walls. And the red, blue and green lights brighten the falling water in the evenings. Also the relief of the palm tree and turtle symbolizes the University Identity. The wall is comprehends not only the day and the night but four seasons. The Water, Lights, and the Relief are coordinates well along with the new building in campus.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.320-326
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• 2000

The canned motor of 3-phase induction is used for main coolant pump(MCP). The type of motor is canned-motor that stator and rotor are welded by sealed can. So, cooling water flows in the air gap of the canned motor as an independent cycling cooling system from the air gap to yoke of the motor to prevent high temperature of stator can and to lubricate bearing. Heat exchange is occurred between cooling water in the air gap and cooling water from the exterior pump to prevent rising of temperature in the motor. I has to analyze the characteristics of can exactly because the loss and the heat in the can are very important to design MCP. Therefore, thermal analysis is studied considering the effect of eddy-current los induced in the can.