• Title/Summary/Keyword: Non-equilibrium

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Numerical Analysis of River Bed Change Due to Reservoir Failure Using CCHE1D Model (CCHE1D 모형을 이용한 저수지 붕괴에 따른 하상변동 해석)

  • Son, In Ho;Kim, Byunghyun;Son, Ah Long;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.2
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    • pp.219-229
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    • 2016
  • This study presents the analysis of flood and bed deformation caused by reservoir failure. The CCHE1D is used to simulate 1D non-uniform, non-equilibrium sediment transport and bed deformation. The CCHE1D deals with the adaptation length for non-equilibrium sediment, classified sediment particle for non-uniform sediment and mixing layer for the exchange with the sediment moving with the flow. The model is applied to Ha!Ha! river basin where was experienced reservoir failure in 1996 to analyze non-uniform and non-equilibrium sediment transport. The calculations are compared with morphological bed changes of pre- and post-flood. In addition, model sensitivity to main parameters involving adaptation length ($L_{s,b}$), non-equilibrium coefficient (${\alpha}_s$), mixing layer thickness (${\delta}_m$) and porosity (p') is analyzed. The results indicates that thalweg change is the most sensitive to non-equilibrium coefficient (${\alpha}_s$) among those parameters in the study area.

REGULARIZED PENALTY METHOD FOR NON-STATIONARY SET VALUED EQUILIBRIUM PROBLEMS IN BANACH SPACES

  • Salahuddin, Salahuddin
    • Korean Journal of Mathematics
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    • v.25 no.2
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    • pp.147-162
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    • 2017
  • In this research works, we consider the general regularized penalty method for non-stationary set valued equilibrium problem in a Banach space. We define weak coercivity conditions and show that the weak and strong convergence problems of the regularized penalty method.

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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AN APPROACH TO THE PROBLEM OF COMMON POOL RESOURCES THROUGH AN EXTENSION OF THE EQUILIBRIUM CONCEPT

  • Bae, Jaegug;Kim, Jongseok;Kang, Eun Sook
    • Honam Mathematical Journal
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    • v.35 no.2
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    • pp.225-234
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    • 2013
  • Many studies of experimental economics have produced outcomes which contradict the predictions of Nash equilibrium, which relies heavily upon the premise of selfishness of an individual. In the games involving contexts of social conflicts represented by the prisoners' dilemma game, the experiments yields outcomes quite different from what are predicted by the conventional wisdom. In order to fill this gap between the conventional Nash Equilibrium and experimental outcomes, non-selfish (or other-regarding) motives of human behavior are introduced and then a new equilibrium concept, RAE-equilibrium is developed. It is also proved that an RAE-equilibrium exists under quite general conditions. Then it is applied to the prisoners' dilemma game that some of the experimental outcomes can be explained.

Surface Cleaning of Polyethylene Terephthalate Film with Non-equilibrium Atmospheric Discharge Plasma

  • Sung, Youl-Moon
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.2
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    • pp.79-83
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    • 2008
  • The dampness by treating the surface with polyethylene terephthalate (PET) film was measured to grasp the plasma parameters and was observed the surface condition with an atomic force microscope (AFM) to find the causes of the dampness. Also, the vibrational and rotational temperatures in the plasma were calculated after identifying the radicals within the plasma by analyzing the emission spectral with an emission spectrum. The hydrophilic properties were enhanced, by treating the surface of the PET film with non-equilibrium atmospheric discharge plasma. When the rotational temperature was 0.22 to 0.31 eV within the plasma, surface modification control could be easily carried out to surface treatment of PET film on non-equilibrium atmospheric pressure plasma.

Numerical Analysis on Heat Transfer Characteristics in Silicon Boated by Picosecond-to-Femtosecond Ultra-Short Pulse Laser (펨토초급 극초단 펄스레이저에 의해 가열된 실리콘 내의 열전달 특성에 관한 수치해석)

  • 이성혁;이준식;박승호;최영기
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.10
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    • pp.1427-1435
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    • 2002
  • The main aim of the present article is numerically to investigate the micro-scale heat transfer phenomena in a silicon microstructure irradiated by picosecond-to-femtosecond ultra-short laser pulses. Carrier-lattice non-equilibrium phenomena are simulated with a self-consistent numerical model based on Boltzmann transport theory to obtain the spatial and temporal evolutions of the lattice temperature, the carrier number density and its temperature. Especially, an equilibration time, after which carrier and lattice are in equilibrium, is newly introduced to quantify the time duration of non-equilibrium state. Significant increase in carrier temperature is observed for a few picosecond pulse laser, while the lattice temperature rise is relatively small with decreasing laser pulse width. It is also found that the laser fluence significantly affects the N 3 decaying rate of Auger recombination, the carrier temperature exhibits two peaks as a function of time due to Auger heating as well as direct laser heating of the carriers, and finally both laser fluence and pulse width play an important role in controlling the duration time of non-equilibrium between carrier and lattice.

A Study on the Evaluation of Equilibrium Price between PSTN and VoIP Service (PSTN과 VoIP 서비스 간의 균형가격 도출에 관한 연구)

  • Yoon, Sang-Hum;Jin, Xiang-Hua;Park, Jong-Heon;Park, Young-Jun;Juhn, Jae-Ho;Ha, Gui-Ryong
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.3
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    • pp.137-145
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    • 2010
  • The objective of this paper is to evaluate the equilibrium price between PSTN and VoIP telephony services in the case of non-linear utility function. Currently there are two types of wired phone services we are known PSTN (Public Switched Telephone Network) and VoIP (Voice over Internet Protocol). The PSTN telephony which provide high quality service and VoIP which provides relatively low quality service form a vertically differentiated oligopoly. Therefore, the evaluation of the equilibrium price between PSTN and VoIP services is very important to wired phone service providers. The equilibrium price depends on the state of the service cost function has been proved different value. This paper was evaluated each equilibrium price for the state of the linear cost function and non-linear cost function. Subsequently, this paper analyzed the demand of both services and the equilibrium profit which can maximize the profit of both service providers.

Investigation of the observed solar coronal plasma in EUV and X-rays in non-equilibrium ionization state

  • Lee, Jin-Yi;Raymond, John C.;Reeves, Katharine K.;Shen, Chengcai;Moon, Yong-Jae
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.53.1-53.1
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    • 2018
  • During a major solar eruption, the erupting plasma is possibly out of the equilibrium ionization state because of its rapid heating or cooling. The non-equilibrium ionization process is important in a rapidly evolving system where the thermodynamical time scale is shorter than the ionization or recombination time scales. We investigate the effects of non-equilibrium ionization on EUV and X-ray observations by the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory and X-ray Telescope (XRT) on board Hinode. For the investigation, first, we find the emissivities for all the lines of ions of elements using CHIANTI 8.07, and then we find the temperature responses multiplying the emissivities by the effective area for each AIA and XRT passband. Second, we obtain the ion fractions using a time-dependent ionization model (Shen et al. 2015), which uses an eigenvalue method, for all the lines of ion, as a function of temperature, and a characteristic time scale, $n_et$, where $n_e$ and t are density and time, respectively. Lastly, the ion fractions are multiplied to the temperature response for each passband, which results in a 2D grid for each combination of temperature and the characteristic time scale. This is the set of passband responses for plasma that is rapidly ionized in a current sheet or a shock. We investigate an observed event which has a relatively large uncertainty in an analysis using a differential emission measure method assuming equilibrium ionization state. We verify whether the observed coronal plasmas are in non-equilibrium or equilibrium ionization state using the passband responses.

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Effect of critical flow model in MARS-KS code on uncertainty quantification of large break Loss of coolant accident (LBLOCA)

  • Lee, Ilsuk;Oh, Deogyeon;Bang, Youngseog;Kim, Yongchan
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.755-763
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    • 2020
  • The critical flow phenomenon has been studied because of its significant effect for design basis accidents in nuclear power plants. Transition points from thermal non-equilibrium to equilibrium are different according to the geometric effect on the critical flow. This study evaluates the uncertainty parameters of the critical flow model for analysis of DBA (Design Basis Accident) with the MARS-KS (Multi-dimensional Analysis for Reactor Safety-KINS Standard) code used as an independent regulatory assessment. The uncertainty of the critical flow model is represented by three parameters including the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio, and their ranges are determined using large-scale Marviken test data. The uncertainty range of the thermal non-equilibrium factor is updated by the MCDA (Model Calibration through Data Assimilation) method. The updated uncertainty range is confirmed using an LBLOCA (Large Break Loss of Coolant Accident) experiment in the LOFT (Loss of Fluid Test) facility. The uncertainty ranges are also used to calculate an LBLOCA of the APR (Advanced Power Reactor) 1400 NPP (Nuclear Power Plants), focusing on the effect of the PCT (Peak Cladding Temperature). The results reveal that break flow is strongly dependent on the degree of the thermal non-equilibrium state in a ruptured pipe with a small L/D ratio. Moreover, this study provides the method to handle the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio in the system code.

Microstructural evolution and mechanical properties of $Al_{71.6}Ge_{28.4}$ eutectic alloy ($Al_{71.6}Ge_{28.4}$ 공정합금의 미세구조 및 기계적 성질의 평가)

  • Park, Jin-Man;Yook, Wan;Kim, Do-Hyang
    • Journal of Korea Foundry Society
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    • v.27 no.4
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    • pp.167-172
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    • 2007
  • In the present study, the microstructural evolution and mechanical properties of $Al_{71.6}Ge_{28.4}$ eutectic alloy have been investigated. Stable (fcc ${\alpha}$-Al and diamond cubic ${\beta}$-Ge) and various metastable crystalline (monoclinic, rhombohedral) phases were produced by competitive phase selection during non-equilibrium processing methods i.e. melt spinning and injection casting. The as-injection casted samples containing metastable-equilibrium eutectic (${\alpha}$-Al + monoclinic) structure showed much higher strength than samples with equilibrium eutectic (${\alpha}-Al+{\beta}-Ge$) structure but plasticity disappointingly diminished. In order to endow the enhanced ductility without significant strength drop, the alloys was heat-treated at transition temperature from metastable phase to stable phase. The annealed specimen displayed the phase transformed microstructural evolution and enhanced macroscopic plasticity.