• Title/Summary/Keyword: Natural energy

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RELAP5 Analysis of a Condensation Experiment in an Inverted U-tube

  • Park, Chul-Jin;Lee, Sang-Yong
    • Proceedings of the Korean Nuclear Society Conference
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    • 한국원자력학회 1995년도 추계학술발표회논문집(1)
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    • pp.383-388
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    • 1995
  • Two-phase transient phenomena in the noncondensable gas-filled closed loop was investigated numerically using the RELAP5/MOD3 version 3.1 computer code. The condensation heat transfer correlation for noncondensable gases was studied in detail. Two modes of the reflux condensation which can be characterized by countercurrent flow of steam and its condensed water and the oscillatory between reflux condensation and natural circulation were predicted well. However, the natural circulation mode which the condensed water carried over the U-bend concurrently with steam was failed to predict.

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Flow Field Measurement of Natural Convection in a Rectangular Cavity Using Laser Speckle Photography (레이저 반점(斑點)을 이용한 사각형(四角形) 공동(空洞)내의 자연대류(自然對流) 유동장(流動場) 측정(測定))

  • Yang, Soong-Hyo;Chung, Woo-Nam;Park, Chan-Kuk;Kang, Yung-Kyu
    • Solar Energy
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    • 제9권2호
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    • pp.51-57
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    • 1989
  • A two-dimensional velocity map of natural convection in a rectangular cavity is determined using laser speckle photography. Isovelocity contour drawn by spatial filtering and local velocity by pointwise method are obtained. These results are compared with those of numerical analysis.

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Instabilities of Natural Convection in a Shallow Fluid Layers (얇은 유체층(流體層)에 있어서 자연대류(自然對流)의 불안정성(不安定性))

  • Yang, Soong-Hyo;Park, Chan-Kuk
    • Solar Energy
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    • 제8권1호
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    • pp.33-40
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    • 1988
  • The characteristics of thermal instabilities of natural convection in a horizontal fluid layer bounded below by a rigid plate and above by an interface with a passive gas is presented. The critical Grashof number decreases as the surface tension gradient effect (Marangoni effect) at the interface increases and the flow remains unstable for a critical Marangoni number depending on Prandtl numbers. These results are in substantial agreement with those of Smith and Davis.

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The R&D - Validity of Gas hydrates (가스 하이드레이트 R&D 타당성 평가)

  • Kim Yu Jeong;Kim Seong Yong;Huh Dae-Gee
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.647-650
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    • 2005
  • Gas hydrates draw great at tent ion recently as a new clean energy resources substituting conventional oil and gas hydrate its presumed huge amount of volume reaching 10 trillion tons of gas and environmentally friendly characteristics. Gas hydrate can contribute to the rapidly increasing consumption of natural gas in Korea and achieve the self support target by 2010 which is $30\%$ of total natural gas demand. This paper shows the importance and benefit of Gas hydrate comparing with new & renewable energy in Korea

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Design and Implementation of the Script-based EMS for Flexible Management of Stand-alone Microgrid (독립형 마이크로그리드의 유연한 운영을 위한 스크립트 기반 EMS 설계 및 구현)

  • Kim, Joon-Hyoung;Jung, Sung-Hwan
    • Journal of Korea Multimedia Society
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    • 제18권10호
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    • pp.1231-1240
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    • 2015
  • Nowadays, in islands where electricity should be provided autonomously, stand-alone microgrid technologies using renewable energy such as sunlight generation and wind power generation come into wide use. The microgrid electricity generation using renewable energy is greatly affected by the natural environment of a site. In order to maintain stable electricity supply for fluctuating electricity generation due to natural environment, the energy management via EMS is positively necessary. In existing stand-alone microgrid EMS, system operation logic is not changeable flexibly because compiled or builded codes are released into the EMS of a site, respectively. In this paper, we designed a flexible operating script-based microgrid EMS Framework for various sites and applied it to some island sites. We could confirm its usability.

Strain Energy Characterics of Antisymmetric Angle-Ply Laminated Plates (역대칭 Angle-Ply 적층판의 변형에너지 특성에 관한 연구)

  • Park, Sung Jin
    • Journal of Korean Society of Steel Construction
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    • 제12권6호
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    • pp.691-700
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    • 2000
  • A powerful analytical procedure and strain energy analysis to investigate the free vibration of antisymmetric angle-ply laminated plates, having one pair of opposite edges simply supported, are develped on the basis of the Yang, Norris and Stavsky (YSN) theory. The equation of motion of the plate are solved by the use of collocation method. A range of results are presented for plates to show the effects of modulus ratio and number of layers on natural frequency. In addition, an analysis of the strain energy distributions is used as an aid for the better understanding of the vibration characteristics of the plates.

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A Unique Function of Reaction Path (I). Definition and Approximation (반응 경로의 일의적 함수 (제 1 보). 정의 및 근사)

  • Kim, Ho-Jing;Jang, Hyo-Weon
    • Journal of the Korean Chemical Society
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    • 제32권2호
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    • pp.94-102
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    • 1988
  • A quantitative description of the principle of least motion is suggested. The reaction path function of electronic variables, its norm and the reaction path average energy, which are unique for a given reaction path on a potential energy surface of a reacting system, are defined and their characteristics are discussed. It is postulated that the norm of the function and the average energy can be used as a criterion for identification of the preferred path of a unimolecular isomerization reaction. For a molecule with a certain symmetry, the preferred path, with which Woodward-Hoffmann rule agrees, is immediately identified without laborious computation.

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Analysis on the Ventilation Rate of Express Bus according to the Geometry of Vent (고속버스의 환기구 형태에 따른 환기량 분석)

  • Shin, In-Hwaw;Yoo, Ho-Chun
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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    • pp.174-178
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    • 2011
  • This paper deals with the free cooling system of express bus using natural energy source in order to improve the room air quality and save cooling energy. In an express bus, there are may passengers in unit area, requiring the improvement of air quality and giving higher energy saving efficiency. Particularly, the express buses running fast make it easy to take in outdoor air at a flow rate controllable with a damper mechanism. This paper proposes the analysis on the air flow achieved by a damper controlled vertically and horizontally in order not to deteriorate the ride comfort of the passengers.

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Photodissociation Dynamics of Formic Acid at 206 nm

  • Kang, Tae-Yeon;Kim, Hong-Lae
    • Bulletin of the Korean Chemical Society
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    • 제27권12호
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    • pp.1997-2001
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    • 2006
  • The photodissociation dynamics of formic acid (HCOOH) at 206 nm have been investigated from rotationally resolved laser induced fluorescence spectra of OH ($^2\Pi$) fragments produced exclusively in the ground state. From the spectra, the rotational energy of the fragments was measured to be $820\;{\pm}\;50\;cm^{-1}$. The translational energy released in the products, which is 87% of the total available energy of the system, was also measured from analyses of the Doppler profiles. Joining these data with quantum chemical molecular orbital calculations, we have concluded that the dissociation should take place along the S1 surface with an exit channel barrier and also that the energy partitioning is determined at the exit channel.