• Title/Summary/Keyword: Reference gas

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DESIGN OPTIMIZATION OF UPPER PLENUM OF PBMR USING RESPONSE SURFACE APPROXIMATION (반응면기법을 이용한 PBMR 기체냉각형 고온가스로 상층부의 최적설계)

  • Lee, S.M.;Kim, K.Y.
    • Journal of computational fluids engineering
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    • v.15 no.3
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    • pp.16-23
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    • 2010
  • Shape optimization of an upper plenum of a PBMR type gas cooled nuclear reactor has been performed by using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) analysis and surrogate modeling technique. The objective function is defined as a linear combination of uniformity of flow distribution in the core and pressure drop in the upper plenum and the core. The ratio of thickness of slot to diameter of rising channels, ratio of height of upper plenum to diameter of rising channels, and ratio of height of the slot at inlet to outlet, are used as design variables for optimization. Design points are selected through Latin-hypercube sampling. The optimal point is determined through surrogate-based optimization method which uses 3-D RANS analyses at design points. The results show that the optimum shape represent remarkably improved performance in flow uniformity and friction loss than the reference shape.

A Study on Charateristic of Modern Packing, 25mm NSW-ring, ppm by Absorption of NH3 gas (25mm NSW-ring, pp.를 충진한 충진탑에서 암모니아 흡수에 의한 유해가스 처리시 충진물의 특성연구)

  • 신은재;박진식
    • Journal of Environmental Science International
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    • v.6 no.4
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    • pp.391-397
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    • 1997
  • The study was carried out to demonstrate the superiority of used packing in view of energy saving and efficiency of mass transfer, comparing with conventional packing. The results are as follows : 1. Owing to low Pressure drop under high load. 25mm NSW-ring, pp. can cause energy saving 2. The unique magnitudes of used packing are as follows $C_G$=5.78, m=0.67, n=0.46 3. Used packing can make high efficiency including energy saving because of low pres sure drop per the number of transfer unit. To rate the characteristic of packing, It should be carried out that the measurement of pressure drop per packing height and per the number of transfer unfit. This study demonstrated the superiority of used packing by carring out above experiment and could be used as basic reference for design and predicting efficiency of packing tower which is tilled with same packing.

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Numerical Analysis on the Oil Film Behaviors of Connecting Rod Bearings Based on the Elastohydrodynamic Lubrication (탄성유체윤활에서 작동하는 커넥팅 로드 베어링의 윤활막 거동에 관한 수치적 연구)

  • 김청균;김한구
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.36-41
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    • 2004
  • The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL's EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.

Numerical Analysis on the Oil Film Behaviors of Connecting Rod Bearings Based on the Elastohydrodynamic Lubrication (탄성유체윤활에서 작동하는 커넥팅 로드 베어링의 윤활막 거동에 관한 수치적 연구)

  • 김청균;김한구
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.34-34
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    • 2004
  • The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL′s EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.

Evaluation of an Ammonia Passive Sampler Using Chamber System

  • Yim, Bong-Been;Kim, Sun-Tae
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.E1
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    • pp.1-8
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    • 2006
  • The purpose of this study was to evaluate the efficiency of a passive sampler in measuring atmospheric ammonia concentrations using chamber system. The ability of the passive sampler to quantitatively determine atmospheric ammonia gas was almost identical to that of the reference method (indophenol method). There was no significant difference between concentrations measured by the two methods. The detection and quantification limits of the ammonia passive sampler were 16.9 ppb and 25.3 ppb, respectively, for a 24-h sampling period. The average coefficient of variation between replicated samplers was $6.7{\pm}4.2%$. The concentrations measured by the two methods (passive sampler and indophenol method) were no significant difference with good a correlation (correlation coefficient=0.964).

ARE GALACTIC WARPS INDUCED BY INTERGALACTIC FLOWS?

  • SANCHEZ-SALCEDO F. J.
    • Journal of The Korean Astronomical Society
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    • v.37 no.4
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    • pp.205-210
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    • 2004
  • The interaction of disk galaxies with intergalactic winds has been invoked as a possible mechanism of the generation of galactic warps. Here we discuss conditions under which intergalactic flows can be relevant for warping field galaxies. Constraints include the heating of the outer disk, the level of asymmetry in the vertical distribution of the volume gas density, the angular frequency of the warp, the symmetry of galactic warps amplitude between the approaching and receding sides of the galaxy, and the speed of the intergalactic flow whether subsonic or supersonic. These constraints are discussed in this paper in reference to the proposal of Lopez-Corredoira et al. that warps can be a natural consequence of accretion flows onto the disk.

Development of Evaluation Method and Experimental Verification of a 300kW Small Engine Cogeneration System (300kW급 소형 엔진 열병합발전시스템의 평가기술 개발 및 실증시험)

  • Choi, Jae-Joon;Park, Hwa-Choon
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.453-458
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    • 2007
  • The importance of the evaluation and verification of small-size cogeneration system has been emphasized because there is no KS-code related to the small-size cogeneration system. The evaluation method of small-size engine cogeneration system was investigated by the reference of Japan evaluation code, JIS B-8122 and international standard organization, ISO-8528. Evaluation method was introduced such as start-test, rapid-load-up and rapid-load-down, etc. The evaluation method was applied to the 300kW small-size gas engine cogeneration system newly developed. The precise and strict evaluation and verification of the system will help the developing cogeneration system to optimum condition. It will also be a base document of KS-Code.

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Characteristics of flow rate according to design parameters of a shroud in outdoor unit (실외기 shroud 설계 인자에 따른 유량 특성)

  • Ryu, Ki-Jung;Kim, Min-Soo;Cha, Woo-Ho;Lee, Kwan-Soo
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.244-249
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    • 2008
  • In this study, the characteristics of flow in outdoor unit were numerically analyzed. Parametric studies were performed to compare the effect of bell mouth height, fan height and fan width concerned with flow rate. The result indicated that the flow rate was dependent on the bell mouth height, while it was negligibly affected by the fan height and fan width. The fan width was found to affect the velocity distribution at heat exchanger face.

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Determination of $\alpha$--pyrrolidone in panax ginseng Extracts (인삼 extract중의 $\alpha$-pyrrolidone검정)

  • 서정상
    • YAKHAK HOEJI
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    • v.13 no.4
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    • pp.111-120
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    • 1969
  • The determination of $\alpha$-pyrrolidone in ginseng extract by gas liquid chromatography (GLC) was established. $\alpha$-Pyrrolidone in extract was tentatively identified by comparison of the relative retention time of sample peak with those of reference compound and coinjection noted peak enhancement. The .alpha.-pyrrolidone peak elimination was demonstrated by formation of oxime when treated with excess of NH$_{2}$OH ${\cdot}$ HCl and NaOH, allowed to stand at room temperature for 5 minute. The elimination was also observed when samples were treated by the same procedure. The above method was proved to be useful for the determination of $\alpha$-pyrrolidone in ginseng extract and in ginseng extract mixed with 51 plant extracts.

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Normalization References for Environmental Index of Construction Projects (시공단계 환경성능지수 개발을 위한 정규화 기준값 산정)

  • Lee, Sanggyu;Kang, Goune;Cho, Hunhee;Kang, Kyung-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.142-143
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    • 2013
  • Green building certifications and environmental assessments are extensively implemented and studied to decrease the environmental impact during the life cycle of buildings. However, most of them are not appropriate to assess the environmental performance during the construction phase due to the difference of environmental factors. To develop an environmental index of construction projects, normalization should be conducted to compare the relative impact of each factor. As a first step, this study deduced normalization references of 4 environmental factors : noise, waste, greenhouse gas, and dust.

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