• Title/Summary/Keyword: Proper Supply Method

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Evaluation on Utilizing Systems of Incineration Heat as Resource cycling Type (자원순환형 소각열 이용시스템에 관한 평가)

  • 정용현
    • Journal of Environmental Science International
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    • v.12 no.4
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    • pp.503-510
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    • 2003
  • How to plan the energy system is one of the keys f3r constructing the Environment -Friendly City. for this reason, a great number of surveys for utilizing unused energy have conducted by a planner. In regard to unused energy, the heat from incineration plants classify as a unused energy having high-exergy-energy. From this point of view, It is studied about the plant systems providing heat to district heating & cooling(D.H.C) and producing electric power. It is divided four system models as system I (10K [kgf/cm$^2$) vapor as outlet of boiler, supply far 10K vapor and return to 60$^{\circ}C$ as supply condition of district heating), system II (30 K vapor as outlet of boiler, supply for 5t vapor and return to 60f as supply condition of district heating), system 111 (30 K vapor as outlet of boiler, supply for 85$^{\circ}C$ hot water and return to 60$^{\circ}C$ as supply condition of district heating), system IV (30 K vapor as outlet of boiler, supply for 47$^{\circ}C$ hot water and return to 40t as supply condition of district heating). The results from the upper condition of four system, System II got a proper on economical benefits and system IV calculated as benefiting on energy saving effects, and suggest indifference curve as the total evaluation method of both economical benefits and energy saving.

A Study on the Stability of High Density SRAM Cell) (고집적 SRAM Cell의 동작안정화에 관한 연구)

  • Choi, Jin-Young
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.11
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    • pp.71-78
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    • 1995
  • Based on the popular 4-transistor SRAM cell, an analytical expression of the minimum cell ratio was derived by modeling the static read operation. By analyzing the relatively simple expression for the minimum cell ratio, which was derived assuming the ideal transistor characteristics, effects of the changes in supply voltage and process parameters on the minimum cell ratio was predicted, and the minimum power supply voltage for read operation was determined. The results were verified by simulations utilizing the suggested simulation method, which is suitable for monitoring the lower limit of supply voltage for proper cell operation. From the analysis, it was shown that the worst condition for cell operation is low temperature and low supply voltage, and that the operation margin can be effectively improved by reducing the threshold voltage of the cell transistors.

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A Numerical Study on the Dynamic Characteristics of Water Hammer Arresters for Building Service Applications (건축설비용 워터햄머흡수기의 동특성에 관한 수치 연구)

  • 노승환;차동진
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.4
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    • pp.269-277
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    • 2002
  • Dynamic characteristics of water hammer arresters installed in a building water supply system have been investigated numerically by utilizing a commercial rode that employs the method of characteristics. Some preliminary results with those arresters produced in this study agree well with the previously reported. Then, the arresters have been incorporated into a water supply pipe system of a $59m^2$ apartment unit constructed by a leading construction company, and their dynamic characteristics, especially on the reduction in the water hammer pressure, are investigated. It is found that the setting of the arresters in the pipe system, which is recommended by the company, may not be proper for reducing the pressure to less than 1082.0 kPa when buick-closure valves in the pipe system are closed within 30 ms at the static pressure of 542.6 kPa. More arresters in the system may be required to meet a pressure criteria.

Formation and Treatment Methods of N-Nitrosodimethylamine (NDMA) in Water and Wastewater (상하수에서 N-Nitrosodimethylamine (NDMA) 발생 및 처리법 비교 분석)

  • Kim, Jongo;Lee, Woo-Bum;Park, Soo-Ho
    • Journal of Korean Society on Water Environment
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    • v.30 no.1
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    • pp.95-101
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    • 2014
  • Overall studies for the N-nitrosodimethylamine (NDMA) formation and treatment methods were conducted. In this study, occurrence in several countries and emerging treatment technologies of NDMA were generally reviewed. The NDMA formation was dependent on pH, contact time, and molar ratio (monochloramine/dimethylamine). The formation was rapidly increased when the molar ratio was greater than 1. It was likely that monochloramine could be related to stimulate NDMA formation. NDMA concentrations in water supply and wastewater plants after disinfection were approximately 10 ng/L and 100 ng/L, respectively. UV oxidation and adsorption processes are regarded as effective technologies for the NDMA removal. It is suggested that the UV oxidation with proper lamps is applied in water supply system.

Dynamic Characteristics of Water Hammer Arresters for Building Service Applications

  • Cha, Dong-Jin
    • International Journal of Air-Conditioning and Refrigeration
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    • v.11 no.1
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    • pp.40-49
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    • 2003
  • Dynamic characteristics of water hammer arresters installed in a building water supply system have been investigated numerically by utilizing a commercial code that employs the method of characteristics. Some preliminary results with those arrester models produced in this study agree well with the previously reported. Then, the arrester models have been incorporated into a water supply pipe system of a 59 $m^2$apartment unit constructed by a leading construction company, and their dynamic characteristics have been investigated, especially on the reduction in the water hammer pressure. It is found that the setting of the arresters in the pipe system, which is recommended by the company, may not be proper for reducing the pressure down below 1,082.0 kPa (10.0 kg$g_f$/$cm^2$) when quick-closure valves in the pipe system are closed within 30 ms at the static pressure of 542.6 kPa (4.5 kg$g_f$/$cm^2$). More arresters in the system may be required to meet pressure criteria stated on the related standards and codes.

Artifical Groundwater Recharge Using Underground Piping Method

  • Ahn, Sang-Jin;Lee, Jong-Hyong
    • Korean Journal of Hydrosciences
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    • v.3
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    • pp.11-29
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    • 1992
  • Recently, rapid industrialization, urbanization and higher living standards accelerate to increase groundwater consumption resulting in continuously dropping groundwater elevations. To maintain enough groundwater volume without dropping groundwater elevations, the proper groundwater rechatge is necessary. The groundwater rechatge can be classified into two categories which are natural rechatge and artiticial rechatge. Even though the natural rechatge through by dired infiltration from the rainfall is desirable, the artificial groundwater rechatge is necessaty when the increment of groundwater consumption exceeds natural recharge rate. Well method and scattering method are utilized as artificial rechatging method, a severe disadvantage, which is the reduction of the void of soil surface, is indicated in the well method. Recently, the underground piping method, which is a scattering method, is receiving increasing attention as a proper recharging method. The method is indirectly to supply water to the underground using an underground piping system. Therefore, the void of soil surface is not severely reduced and better infiltration rate can be achieved. In this paper, the artificial groundwater rechatge using underground piping method is investigated through experiments and numerical analysis. The influence of the groundwater by underground piping method is evaluated through comparing recharging heights. Good agreements between experiments and numerical analysis are obtained and the artificial groundwater recharge by underground piping method is well tested and verified.

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The Study on the Present Educational Aspect of Korean Teacher Librarians and Their Supply-demand Problems (우리나라 사서교사 양성현황과 수급문제에 관한 연구)

  • Kim, Sung-Jun;Suh, Jin-Won
    • Journal of Korean Library and Information Science Society
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    • v.39 no.3
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    • pp.161-186
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    • 2008
  • Through the present training condition of Korean teacher librarians and their supply-demand prospects, this paper pointed out problems both of the educational system and of its supply-demand and suggested the solution as well. Particularly, focusing on the educational system of teacher librarians and the present condition of the training organizations, this paper predicted their supply ability in the future and analyzed the demand which is necessary, when applying the standards of Korean Library Association and School Library Promotional Law with the selective situation of teacher librarians. In this way, the problems of supply-demand imbalance were indicated and, as a method for training the proper number which is required for the future demand, the rearrangement of the approval number of a course of study for the teaching profession and the establishment of Library and Information education department in education college were proposed.

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Design of Hot-water wit an Electric Instantaneous Water Heating Unit (분리형 전기순간가열기에 의한 온수 비데 설계)

  • 고석조;김창동
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.69-72
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    • 2004
  • There are an electronic and a manual type in Bidet. The electronic bidet has some advantages. it supplies multiple functions and is up easily. However, it has frequent defects and a high price. The manual bidet is not need to supply electric and is cheaper than the electronic type. However, it is needed to supply hot water and is hard to set up. In order to solve these defects, this study designed a bidet heating unit using an electric instantaneous water heating method. To get a proper heating elements, experiments were performed about a Ni-Cr heater and a film heater.

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Optimization for Flow Uniformity on the Selective Catalytic Reduction (SCR) System of a Steam Supply Boiler (열병합 보일러 SCR 장치의 유동 균일화를 위한 최적화 연구)

  • Park, Young-Bin;Jang, Choon-Man
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.415-420
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    • 2009
  • Selective Catalytic Reduction(SCR) has been used for the reduction of $NO_x$ in a steam supply boiler. Recently, the reduction of $NO_x$ becomes an important research field because of its negative effect on an environment. Shape optimization of circular poles installed in the chamber, which is located in upstream of a SCR, has been performed using response surface method and three-dimensional Navier-Stokes analysis to enhance gas flow uniformity. Three design parameters, diameter, arranging angle and stretching ratio of circular poles, are considered in the present study. Throughout the shape optimization of a circular pole, gas flow uniformity is successfully increased by decreasing local recirculation flow in a square duct chamber. Recirculation flow observed in the corner of the square duct can be reduced by proper installation of a guide vane or a blunt body. Detailed flow characteristics are also analyzed and discussed.

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The Rearch Of Method in the Appropriate number of Demand and Supply of OMD (한의사인력(韓醫師人力) 공급(供給)의 적정화방안(適定化方案) 연구(硏究))

  • Lee, Jong-Soo
    • The Journal of Korean Medicine
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    • v.19 no.1
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    • pp.299-326
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    • 1998
  • 1. Comparison of demand and supply A. Assumption of estimation of demand and supply we will briefly assumptions used for presumption once more before comparing the result of estimation of demand and supply examined previously 1) supply - The average applying rate for state. examination of graduate: ${\alpha}$=1.03109 - The ratio of successful applicants of state examinations: ${\beta}$=0.97091 - Mortality classified by age : presumed data of the Bureau of statistics - Emigrating rate: 0 % - Time of retire: unconsidered - An army doctor number: unconsidered and regard number of employed oriental medicine doctor. - Standard of 1995 : The number of survival oriental medicine doctor is 8195. the number of employed oriental medicine doctor is 7419. 2) demand - derivated demand method Daily the average amount of medical treatment: according to medical insurance federation data. there is 16 or 6 non allowance patient, we consider amount of medical treatment as 22 persons in practical because 21.94 persons (founded practical examination) are converted to allowance in comming demand. Daily the proper amount of medical treatment: 7 hours form -35 persons 5 hours 30 minutes form -28 persons. Yearly medical treatment days: 229 days. 255 days. 269 days . Increasing rate of visiting hospital days: -1996 year. 1997 year. 1998 year- . Rate of applying insurance: yearly average 71.51% (among the investigated patient) B. Comparison of total sum result 1) supply (provision) Table Ⅳ-1 below shows the estimation of the oriental medicine doctor in the future.

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