• Title, Summary, Keyword: equilibrium process

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Thermodynamic promoter effects on the phase equilibrium of BFG(Blast Furnace Gas) hydrate (촉진제 첨가에 따른 철강공정 배기가스 하이드레이트 상평형 영향)

  • Lee, Bo Ram;Sa, Jeong-Hoon;Park, Da-Hye;Kwak, Kye-Hoon;Lee, Kun-Hong
    • 한국신재생에너지학회:학술대회논문집
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    • pp.125.1-125.1
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    • 2011
  • $CO_2$ separation from a flue gas by using the gas hydrate technology was suggested by Kang et al. They reported phase equilibrium conditions of mixed gases composed of $CO_2$ and N2 with THF as a thermodynamic promoter. In this study, we reported the phase equilibrium conditions of a mixed gas which had a realistic composition of the blast furnace gas (BFG) emitted from the steel-making process. The phase equilibrium measurements were done by using the "continuous" QCM method, and the results demonstrate that this method is efficient and as accurate as the conventional temperature search method.

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Application of Thermodynamic Models for Analysis on SI Thermochemical Hydrogen Production Process (SI 열화학 수소 생산 공정의 분석을 위한 열역학 모델의 적용)

  • Lee, Jun Kyu;Kim, Ki-Sub;Park, Byung Heung
    • Journal of Institute of Convergence Technology
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    • v.2 no.2
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    • pp.30-34
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    • 2012
  • The SI thermochemical cycle process accomplishes water splitting through distinctive three chemical reactions. We focused on thermodynamic models applicable to the process. Recently, remarkable models based on the assumed ionic species have been developed to describe highly nonideal behavior on the liquid phase reactions. ElecNRTL models with ionic reactions were proposed in order to provide reliable process simulation results for phase equilibrium calculations in Section II and III. In this study, the current thermodynamic models of SI thermochemical cycle process were briefly described and the calculation results of the applied ElecNRTL models for phase equilibrium calculations were illustrated for binary systems.

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A Study on the Equilibrium-Pricing Mechanism of Apartment (아파트의 가격형성 메커니즘에 관한 연구)

  • Chung, J.-Young;Yoon, Tae-Kwon
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.6
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    • pp.65-74
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    • 2008
  • The aim is to get comprehensive view point for the price of apartment. Apartment construction cost is the sun of land cost and building cost. Land price reflects the value of location where building stands. When the gap between price and affordability is narrow enough, effective demand promote apartment construction. The today's trends of rising price, which began in apartment housing, spreads to real estates market and finally overall consumer price. Problem is that price is decided only by supplier's interest. Equilibrium-pricing is common process in housing market. However it is important to review hedonic price and the factor of housing services and focused on the affordability of demanders. AHP analysis was used to study real needs and preference of demanders and dealt with 200 interviewees with brief checklists. We found that social factor is more important than building cost or site development. Especially location of apartment is most important to affect environment quality and accessibility to facilities.

Thermochemical Performance Analysis of Liquid Rocket Nozzle (액체로켓 노즐의 열화학적 성능 해석)

  • Choe,Jeong-Yeol;Choe,Hwan-Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.85-96
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    • 2003
  • For a design of rocket engine nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be used as an efficient design tool for predicting maximum thermodynamic performance of the nozzle. 10 this study, a chemical equilibrium flow analysis code was developed for the design of hydrocarbon fueled rocket engines. 10 oder to understand the thermochemical characteristics occurring in a nozzle through the expansion process, such as recombination of chemical components and the accompanying energy recovery, chemical equilibrium flow analysis was carried out for the KSR-III rocket engine nozzles together with frozen flow and non-equilibrium flow analyses. The performance evaluation based on the present KSR-III nozzle flow analyses has provided an understanding of the thermochemical process in the nozzle and additionally, it has confirmed that the newly designed nozzle shape modified to have a reduced exit area ratio is an adequate design for obtaining an increased ground thrust.

Chemical Equilbrium Analysis of the $30\;ton_f$ - class KARI LRE Nozzle Flow (KARI 30톤급 액체 로켓 엔진 노즐 유동 화학 평형 해석)

  • Lee, Dae-Sung;Kang, Ki-Ha;Cho, D.R.;Choi, Jeong-Yeol;Choi, H.S.
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.3
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    • pp.9-15
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    • 2008
  • Nozzle flow analyses of $30\;ton_f$-class KARI liquid rocket engine for high altitude propulsion are carried out using a chemically frozen and equilibrium flow analysis code developed previously. It is considered that the combined frozen- and shifting- equilibrium analysis is cost-effective regarding the convergence characteristics and modeling uncertainties, though the non-equilibrium analysis is most reliable approach. A dependable performance prediction could be attainable through the present analyses that account for the recombination process and thermal and kinetic energy recovery during the expansion process with viscous effects.

Synthesis of Nanoporous Carbon as a Gas Adsorbent by Reverse Replication Process of Silica Template

  • Cho, Churl-Hee;Kim, Joon-Soo;Kim, Hong-Soo;Ahn, Young-Soo;Han, Moon-Hee;Yoo, Jong-Sung
    • Journal of the Korean Ceramic Society
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    • v.40 no.6
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    • pp.519-524
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    • 2003
  • Porous carbon with high surface area and pore volume was prepared by a reverse replication process and its toluene equilibrium adsorption behavior was investigated. The preparation process of the porous carbon was composed of fellowing sub-processes in series: synthesis and template preparation of silica gel, impregnation and polymerization of DVB monomer in silica template, carbonization of DVB polymer in a silica-polymer composite, and HF-assisted selective etching of silica in carbon-silica composite. The prepared porous carbon was nano porous and had ultrahigh specific surface area (2007 ㎡/g) and large pore volume (3.07 ㎤/g). The nanoporous carbon showed rapid toluene adsorption rate and good toluene adsorption capacity, compared with a commercial Y-type zeolite. In the present study, a reverse replication process to prepare nanoporous carbons will be introduced and its application potential as a gas adsorbent will be discussed.

A Research on the Conception Change Process of Secondary School Chemistry Major Teachers Related to the Evaporation Phenomena in the Air (대기 중의 증발 현상에 대한 중등학교 화학전공 교사들의 개념 변화 과정에 대한 연구)

  • Yang, Gee-Chang;Paik, Seoung-Hey
    • Journal of the Korean Chemical Society
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    • v.52 no.1
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    • pp.84-95
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    • 2008
  • In this study, preconceptions held by chemistry major secondary school science teachers were searched in relation to explanations of water evaporation phenomena with phase equilibrium diagrams. 25 chemistry major science teachers were selected to complete questionnaires developed in this study and 6 among of them were selected to participate in follow-up interviews. Among these, 10 participants were selected for an evaluation of the change of their preconceptions through lessons developed in this study. From the results, it was found that many teachers believed that the phase equilibrium diagram could not explain water evaporation phenomena. They also thought that there was no relation between vapor pressure and the vertical axis of the phase equilibrium diagram. However, after the lessons in earth science, they recognized that the vapor pressure curve of the phase equilibrium diagram could be explained by adopting a saturated vapor curve. Because they had known the process of application the conceptions of saturated situation, nonsaturated situation, process of equilibrium movement in saturated vapor curve. They could understand natural phenomena such as evaporation with the phase equilibrium diagram through a change in their conceptions as guided from science lessons integrating earth science and chemistry.

Quantum Transition Properties of Quasi-Two Dimensional Si System in Electron Deformation Potential Phonon Interacting (전자 포텐셜 변형과 포논 상호작용에 의한 준 이차원 Si 구조의 전도 현상 해석)

  • Lee, Su-Ho;Kim, Young-Mun;Kim, Hai-Jai;Joo, Seok-Min
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.3
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    • pp.129-134
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    • 2017
  • We investigated theoretically the quantum optical transition properties of Si, in quasi 2-Dimensinal Landau splitting system, based on quantum transport theory. We apply the quantum transport theory (QTR) to the system in the confinement of electrons by square well confinement potential under linearly polarized oscillating field. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). In order to analyze the quantum transition, we compare the temperature and the magnetic field dependencies of the QTLW and the QTLS on four transition processes, namely, the intra-leval transition process, the inter-leval transition process, the phonon emission transition process and the phonon absorption transition process.

A Study on the Stochastic User Equilibrium Assignment (확솔적 이용자 평형통행 배분에 관한 연구)

  • 이승재;전경수;임강원
    • Journal of Korean Society of Transportation
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    • v.8 no.1
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    • pp.55-71
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    • 1990
  • The behavioral mechanism underlying the traffic assignment model is a choice, or decision-making process of traveling paths between origins and destinations. The deterministic approach to traffic assignment assumes that travelers choose shortest path from their origin-destination pair. Although this assumption seems reasonable, it presumes that all travelers have perfect information regarding travel time, that they make consistently correct decision, and that they all behave in identical fashion. Stochastic user equilibrium assignment relaxes these presumptions by including a random component in traveler's perception of travel time. The objective of this study is to compare "A Model of Deterministic User Equilibrium Assignment" with "Models of Stochastic User Equilibrium Assignment" in the theoretical and practical aspects. Specifically, SUE models are developed to logit and probit based models according to discrete choice functions. The models were applied to sioux Falls net ork consisting of 24 zones, 24 nodes and 76 links. The distribution of perceived travel time was obtained by using the relationship between speed and traffic flow.

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