• Title/Summary/Keyword: equilibrium analysis

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Partial Equilibrium Analysis and Long-run Equilibrium: Full Industry Equilibrium (부분균형분석과 장기균형: 산업완결균형)

  • Park, Man-Seop
    • 사회경제평론
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    • v.31 no.3
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    • pp.131-163
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    • 2018
  • The long-run equilibrium of an economy is a situation where all firms in the economy realize the condition of 'extra profits = 0'. The conventional partial equilibrium (PE) analysis, which is based on the assumption of 'ceteris paribus', conflicts logically with the long run equilibrium. 'Full industry equilibrium' (FIE) deals with long-run equilibrium in the framework of partial equilibrium; FIE requires the adjustment of more variables than PE. The comparative statics analysis of FIE shows that many results of the conventional PE does not hold. The present paper intends to introduce the background and significance of FIE. In its course, the paper discusses similarities and differences between FIE and the Capital Controversies of the 1960s and 1970s, and highlights the critical and constructive significances of FIE.

Thermochemical Performance Analysis of KSR-III Rocket Nozzle (KSR-III 로켓 노즐의 열화학적 성능해석)

  • Choi, J.Y.;Choi, H.S.;Kim, Y.M.
    • 한국연소학회:학술대회논문집
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    • 2001.06a
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    • pp.90-98
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    • 2001
  • Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed, those were coupled with the methods of computational fluid dynamics code. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis. The approaches were used for the performance prediction of KSR-III Rocket, and compared with the theoretical results from NASA CEA (Chemical Equilibrium with Applications) code.

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A Numerical Analysis Approach for Design of Cable Dome Structures (케이블 돔 구조물 설계를 위한 수치해석 방법)

  • Kim, Jae-Yeol;Jang, Dong-Woo
    • Proceeding of KASS Symposium
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    • 2008.05a
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    • pp.89-94
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    • 2008
  • This paper deals with the method of self-equilibrium stress mode analysis of cable dome structures. From the point of view of analysis, cable dome structure is a kind of unstable truss structure which is stabilized by means of introduction of prestressing. The prestress must be introduced according to a specific proportion among different structural member and it is determined by an analysis called self-equilibrium stress mode analysis. The mathematical equation involved in the self-equilibrium stress mode analysis is a system of linear equations which can be solved numerically by adopting the concept of Moore-Penrose generalized inverse. The calculation of the generalized inverse is carried out by rank factorization method. This method involves a parameter called epsilon which plays a critical role in self-equilibrium stress mode analysis. It is thus of interest to investigate the range of epsilon which produces consistent solution during the analysis of self-equilibrium stress mode.

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Static equilibrium and linear vibration analysis of a high speed electric train system (고속전철 시스템의 정적평형 및 선형진동 해석)

  • 김종인;유홍희;황요하
    • Journal of the Korean Society for Railway
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    • v.2 no.4
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    • pp.1-8
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    • 1999
  • A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix. The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power car vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the two are identified in this paper.

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Thermochemcial Characteristics of Rocket Nozzle Flow and Methods of Analysis (로켓 노즐 유동의 열/화학적 특징 및 해석 기법)

  • Choi Jeong-Yeol
    • 한국전산유체공학회:학술대회논문집
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    • 2001.05a
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    • pp.144-148
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    • 2001
  • Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed those were coupled with the methods of computational fluid dynamics. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis, and a test was made for a bell nozzle at typical operation condition. As a results, the characteristics of the approaches were discussed in aspects of rocket performance, thermal analysis and computational efficiency.

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Numerical Study of Chemical Performance of 30 tonf -class LRE Nozzle of KARI

  • Kang, Ki-Ha;Lee, Dae-Sung;Cho, Deok-Rae;Choi, H.S.;Choi, J.Y.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.448-451
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    • 2008
  • Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were used to rocket nozzle flow, those were coupled with the methods of computational fluid dynamics code. For a design of high temperature rocket nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be an efficient design tool for predicting maximum thermodynamic performance of the nozzle. Frozen fluid analysis presents the minimum performance of the nozzle because of no consideration for the energy recovery. On the other hand, the case of chemical-equilibrium analysis is able to forecast the maximum performance of the nozzle due to consideration for the energy recovery that is produced for the fast reaction velocity compared with velocity of moving fluid. In this study, using the chemical equilibrium flow analysis code that is combined the modified frozen-equilibrium and the chemical-equilibrium. In order to understand the thermochemical characteristic components and the accompanying energy recovery, shifting-equilibrium flow analysis was carried out for the 30 $ton_f$-class KARI liquid rocket engine nozzle together with frozen flow. The performance evaluation based on the 30 $ton_f$-class KARI LRE nozzle flow analyses will provide an understanding of the thermochemical process in the nozzle and performances of nozzle.

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Analysis of Dynamic Equilibrium Configuration of Speed Governor (조속기의 동적 평형위치 해석)

  • Kang, Juseok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.4733-4738
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    • 2013
  • This paper proposes a method to obtain the dynamic equilibrium configuration of a constrained mechanical system by using multibody dynamic analysis. Dynamic equilibrium equations with independent coordinates are derived from the time-dependent constraint equations and dynamic equations of a multibody system. The Newton-Raphson method is used to find numerical solutions for nonlinear algebraic equations that are composed of the dynamic equilibrium and constraint equations. The proposed method is applied to obtain the dynamic equilibrium configuration of a speed governor, and the results are verified on the basis of the results from conventional dynamic analysis. Furthermore, vertical displacements at equilibrium configuration, which varied with the rotational velocity of the speed governor, are calculated, and design parameter analysis of the equilibrium configuration is presented.

Determination of Aqueous Ammonia with Indophenol Method : Comparision and Evaluation for the Reaction-Rate, Equilibrium and Flow-Injection Analysis Methods (인도페놀법을 이용한 수용액 중 암모니아 정량에 관한 연구 : 평형법, 반응속도법, 흐름주입분석법의 비교와 평가)

  • 정형근;김범식
    • Journal of Environmental Science International
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    • v.4 no.1
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    • pp.91-103
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    • 1995
  • The reaction rate, equilibrium, and flow injection analysis methods were fundamentally evaluated for the determination of aqueous ammonia. The selected indophenol blue method was based on the formation of indophenol blue in which ammonium ion reacted with hypochlorite and phenol in alkaline solution. In the optimized reaction condition, the reaction followed 1st order reaction kinetics and the final product was stable. The absorbance measurements before and after the equilibrium were utilized for the reaction rate and equilibrium methods. The reaction rate methods, based on the relative analytical signals for the possibility of eliminating interferents, were shown to have good linear calibration curves but the detection limit and the calibration sensitivity were poorer than those in the equilibrium method. The detection limits were 32-49 pub and 24 pub for the reaction rate and equilibrium methods, respectively In the flow injection analysis, the absorbance was measured before the equilibrium reached and thus resulted in 30% reduction of calibration sensitivity. However, the detection limit was 11 ppb, indicating that the peak-to-peak noise for the blank was remarkably improved. Compared to the manual methods, the optimized experimental condition in a closed reaction system reduced the blank absorbance and the inclusion of ammonia from the atmosphere was prevented. In addition, highly reproducible mixing of sample and reagents and analytical data extracted from continuous recording showed excellent reproducibility.

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Vibration Analysis and Non-linear Equilibrium Equations of a Curved Pipe Conveying Fluid (유체가 흐르는 곡선관의 진동 해석과 비선형 평형 방정식)

  • Jung, Du-Han;Chung, Jin-Tai
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.983-986
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    • 2005
  • Free vibration characteristics of a curved pipe conveying fluid is studied when the pipe is clamped at both ends. Using the perturbation method, the non-linear governing equations divided into two parts; the steady state non-linear equilibrium equations and the linearized equations of motion in the neighborhood of the equilibrium position. The natural frequencies are computed from the linearized equations of motion. In this study, the equilibrium positions are determined by two types of equations, i.e., (1) the non-linear equations, and (2) the equations obtained by neglecting the non-linear terms. The natural frequencies obtained from the non-linear equilibrium equations are compared to those obtained from the linearized equilibrium equations. From the results, as the fluid velocity increases, the equilibrium position should be determined from the nonlinear equations for the vibration analysis of the curved pipe conveying fluid.

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Comparison Analysis of Factor of Safety on Rock Slope in Boeun Region Using Limit Equilibrium Method and Distinct Element Method (한계평형법과 개별요소법을 이용한 보은지역 암반사면 안전율 비교해석)

  • 이지수;유광호;박혁진;민경덕
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.643-650
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    • 2002
  • The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered as unstable since the discontinuities whose orientations are similar to the orientation of the failure plane, are observed in many areas. Therefore, several analysis techniques such as SMR, stereographic analysis, limit equilibrium, numerical analysis, which are commonly used in rock slope stability analysis, are adopted in this area. In order to analyze the stress redistribution and nonlinear displacement caused by cut, which are not obtained in limit equilibrium method, the UDEC and shear strength reduction technique were used in this study Then the factors of safety evaluated by shear strength reduction technique and limit equilibrium were compared. In addition, the factor of safety under fully saturated slope condition was calculated and subsequently, the effect of the reinforcement was evaluated.

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