• 제목, 요약, 키워드: equilibrium process

검색결과 846건 처리시간 0.047초

ITERATIVE METHODS FOR GENERALIZED EQUILIBRIUM PROBLEMS AND NONEXPANSIVE MAPPINGS

  • Cho, Sun-Young;Kang, Shin-Min;Qin, Xiaolong
    • 대한수학회논문집
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    • v.26 no.1
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    • pp.51-65
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    • 2011
  • In this paper, a composite iterative process is introduced for a generalized equilibrium problem and a pair of nonexpansive mappings. It is proved that the sequence generated in the purposed composite iterative process converges strongly to a common element of the solution set of a generalized equilibrium problem and of the common xed point of a pair of nonexpansive mappings.

기능화된 실리카 비드를 이용한 수용액상의 중금속 이온의 제거공정에 대한 모사 연구 (A Simulation Study on the Removal Process of the Heavy Metal Ion in Aqueous Solution by the Functionalized Silica Beads)

  • 우윤환;주창업
    • 청정기술
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    • v.17 no.2
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    • pp.150-155
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    • 2011
  • 본 연구에서는 수용액상의 금속이온을 기능화된 구형의 실리카 담체를 이용하여 제거하는 공정에 대하여 유한 차분법을 이용하여 모사하였다. 평형 모델과 비평형 모델을 수립하여 무차원 변수와 각종 변수에 대한 영향을 살펴보았으며 평형 모델과 비평형 모델의 결과를 비교하였다. 평형모델의 경우 Freundlich 등온식을 사용하였으며 비평형 모델의 경우 1차 반응속도를 가정하였다. 평형모델과 비평형 모델의 경우 변수값에 따라 비슷한 경향을 나타내었으며 금속이온 제거공정의 효율을 예측할 수 있었다. 문헌에 제시된 실험값을 활용하여 평형 모델의 예측 결과를 비교한 결과 부합되는 결과를 나타내었다.

Removal of Heavy metal Ions from Aqueous Solutions by Adsorption on Magadiite

  • 정순용;이정민
    • Bulletin of the Korean Chemical Society
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    • v.19 no.2
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    • pp.218-222
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    • 1998
  • Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

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Nash의 협상게임과 Wardrop의 사용자 균형 (Alternating Offers Bargaining Game and Wardrop's User Equilibrium)

  • 임용택
    • 대한교통학회지
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    • v.23 no.4
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    • pp.37-45
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    • 2005
  • 본 연구는 Nash의 협력게임인 협상게임(bargaining game)과 Wardrop의 사용자 균형해와의 관계를 규명하는 데 목적이 있다. Wardrop의 균형은 다수의 운전자들이 교통상황을 정확히 알고 있고(perfect information), 동시에 합리적으로 경로를 선택(rationality)한다는 경직된 가정이 존재하는데, 이는 실제로 존재하는 운전자 상호간의 교류나 타협을 배제하고 있다. 이런 측면에서 운전자간의 교류와 조절과정을 Nash게임의 협상과정(bargaining process)으로 표현할 경우, Wardrop의 경직된 기본가정들을 어느 정도 완화할 수 있을 것으로 보인다. 이를 위하여 본 연구에서는 Nash의 협상게임에 대한 교통망측면의 검토와 Nash의 협상해(bargaining solution)가 Wardrop의 사용자 균형(user equilibrium)과 동일함을 정리(theorem)를 통하여 증명하고 몇 가지 예제로 이를 확인한다. 협상게임은 대표적인 2인 협조게임(two-person cooperative game)으로 본 연구에서도 주로 2인 게임에 대해서 기술하며, 향후 n-인게임(n-person game) 모형에 대해서는 간략히 언급토록 한다.

다공성 물질 안에서의 자연대류 현상에 대한 열역학적 국소평형상태 가정의 고찰 (An Investigation on Local Thermodynamic Equilibrium Assumption of Natural Convection in a Porous Medium)

  • 김인선;남진현;김찬중
    • 대한기계학회:학술대회논문집
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    • pp.112-117
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    • 2000
  • A numerical study on natural convection in a vertical square cavity filled with a porous medium is carried out with Brinkman-Forchheimer-extended Darcy flow model, and the validity of local thermodynamic equilibrium assumption is studied. The local thermodynamic equilibrium refers to the state in which a single temperature can be used to describe a heat transfer process in a multiphase system. With this assumption, the analysis is greatly simplified because only one equation is needed to describe the heat transfer process. But prior to using this assumption, it is necessary to know in what conditions the assumption can be used. The numerical results of this study reveal that large temperature difference between fluid phase and solid phase exists near wall region, paticularily when the convection becomes dominant over conduction. And the influence of flow parameters such as fluid Rayleigh number, fluid Prandtl number, dimensionless particle diameter and conductivity ratio are investigated.

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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.
    • 한국추진공학회:학술대회논문집
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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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블록의 탑재 안전성을 위한 초기 평형 자세 탐색 방법 연구 (A Study on the Methods for Finding Initial Equilibrium Position of a Lifting Block for the Safe Erection)

  • 전도현;노명일;함승호;이혜원
    • 대한조선학회논문집
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    • v.55 no.4
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    • pp.297-305
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    • 2018
  • In a shipyard, block lifting is an important process in the production of ships and offshore structures. Block lifting is a sensitive process because lifting blocks have to be erected with exact positions and orientations. If we use a numerical method for the process, it is important to find tensions of wires and positions of equalizers to maintain the initial equilibrium position of the block. At this time, equations of motion of the block should be solved to calculate the initial equilibrium position of the block. Because the solving technique changes according to the number of equalizers, a suitable equation for the corresponding problem is required. In this study, three types of equations are proposed to find the initial equilibrium position of the block according to the number of equalizers. The Newton-Raphson's method is used to solve nonlinear simultaneous equations and the optimization method is used to determine the appropriate solution to the undetermined problem. To evaluate the applicability of the proposed methods, the dynamic simulations are performed using the tensions calculated from the proposed methods, and the results are discussed. The results show that the proposed methods can be effectively used to determine initial equilibrium position of the block for the block lifting.

Dyeing Behavior of Low Temperature Plasma Treated Wool

  • Kan C.W.
    • Fibers and Polymers
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    • v.7 no.3
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    • pp.262-269
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    • 2006
  • In this paper, the effects of low temperature plasma (LTP) treatment on the dyeing properties of the wool fiber were studied. The wool fibers were treated with oxygen plasma and three types of dye that commonly used for wool dyeing, namely: (i) acid dye, (ii) chrome dye and (iii) reactive dye, were used in the dyeing process. For acid dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased but the final dyeing exhaustion equilibrium did not show any significant change. For chrome dyeing, the dyeing rate of the LTP-treated wool fiber was also increased but the final dyeing exhaustion equilibrium was only increased to a small extent. In addition, the rate of afterchroming process was similar to the chrome dyeing process. For the reactive dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased and also the final dyeing exhaustion equilibrium was increased significantly. As a result, it could conclude that the LTP treatment could improve the dyeing behavior of wool fiber in different dyeing systems.

신기술 제품의 확산에 관한 수요$\cdot$공급의 균형확산모형과 실증분석 (An Equilibrium Diffusion Model of Demand and Supply of New Product and Empirical Analysis)

  • 하태정
    • 기술혁신연구
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    • v.13 no.1
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    • pp.113-139
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    • 2005
  • The purpose of this study is to analyse the diffusion process of personal computer (PC) in Korea during the 1990's. To achieve the goal, five research steps have been done such as the literature survey of diffusion theory, set-up of theoretic equilibrium model of supply and demand, derivation of an equilibrium path using Hamiltonian, and empirical analysis. The empirical analysis has been performed based on that equilibrium path. The results can be summarized as follows : First, technological attribute of diffusing product influences the diffusion speed of Product. It has been proven that the size of the network has a significant effect on the diffusion of PC in empirical study Second, supply factors have an important role in the diffusion process. According to the empirical analysis, decreasing cost of production as a result of technological advance promotes the speed of diffusion. This point seems to be manifest theoretically, but existing empirical models have not included supply factors explicitly, Third, it has been found out that expectation of decreasing cost would influence the speed of diffusion negatively as expected ex ante. Theoretically this result is supported by arbitrage condition of purchasing timing.

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입상 활성탄에 의한 Coomassi Brilliant Blue G의 흡착에 대한 평형, 동력학 및 열역학에 관한 연구 (Study on Equilibrium, Kinetic and Thermodynamic for Adsorption of Coomassi Brilliant Blue G Using Activated Carbon)

  • 이종집
    • 청정기술
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    • v.20 no.3
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    • pp.290-297
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    • 2014
  • 본 연구에서는 활성탄을 사용하여 coomassi brilliant blue G (CBBG)염료를 흡착하는데 필요한 흡착평형과 흡착동역학 및 열역학 파라미터들에 대하여 조사하였다. 등온흡착평형관계로 부터 Langmuir 식과 Freundlich 식의 분리계수를 평가하여 활성탄에 의한 CBBG의 흡착조작이 유효한 처리방법이 될 수 있음을 알았고, Dubinin-Radushkevich 식으로부터 흡착공정이 물리흡착공정임을 알았다. 흡착공정에 대한 동력학적 해석을 통해 흡착반응은 유사이차반응속도식이 유사일차반응속 도식에 비해 일치도가 높은 것으로 나타났으며, 입자내확산이 흡착공정의 지배단계임을 알았다. 유사이차반응속도식을 적용한 열역학적 해석을 통해 평가된 엔탈피 변화값(406.12 kJ/mol)으로부터 흡착공정이 흡열반응으로 진행됨을 알았다. 또한 엔트로피 변화값(1.66 kJ/mol K)은 흡착공정의 무질서도가 증가한다는 것을 나타내었다. 온도가 올라갈수록 자유에너지 값이 감소하는 경향을 보인 것은 활성탄에 대한 CBBG의 흡착반응은 온도가 올라갈수록 자발성이 높아지는 것으로 판단되었다.