• Title/Summary/Keyword: transport equation

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Transport Infrastructure Investment and Its Impacts on Rural Development : Exploratory Analysis for Policy Evaluation (교통 인프라 투자와 농촌지역 발전에 미치는 영향 - 정책평가를 위한 탐색적 분석 -)

  • Lee, Wonho
    • Journal of the Korean association of regional geographers
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    • v.21 no.3
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    • pp.503-514
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    • 2015
  • This study aims to analyze the relationship between transport infrastructure investment and rural development in Korea in a more systematic and empirical way. To do so, we formulate research framework to examine the multi-faceted relationship through extensive literature review and carry out a descriptive study on the spatial patterns of road investment and rural development in Korea. Finally, using the structural equation model, this study carries out the exploratory empirical analysis on the direct and indirect relationship between transport infrastructure investment and rural development. The study finds that the transport infrastructure investment in rural Korea impacts clearly on both the population base promotion and production and income growth through better accessibility. In addition, the investment has an indirect effects on the production and income growth through its influence on the population base promotion. This implies that the transport infrastructure investment in rural Korea so far exerts both long-term and short-term influences on rural development through various channels of impacts.

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Formulation on the Empirical Equation of the Cask Impact Forces by Dimensional Analysis (차원해석을 이용한 사용후 핵연료 수송용기의 충격력 실험식 공식화)

  • Kim Yong-Jae;Choi Young-Jin;Lee Young-Shin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.3
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    • pp.245-254
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    • 2005
  • Radioactive material is used in the various fields. The numbers of transport for radioactive material have been gradually increased in both domestic and International regions. The safety of the cask should be secured to safely transport of radioactive material. The korean atomic law and the IAEA safety standards prescribe regulations lot the safe transport of radioactive material The cask for spent fuel is comprised of the body and the impact limiter. In this study, the empirical equation of the cask impact force is proposed based on the dimensional analysis. Using this empirical equation the characteristics of the impact limiter are analyzed. The results are also validated by comparing with the previous results of the impact area method and the finite element analysis. The present method can be used to predict the impact force of the cask.

Acceleration of the Time-Dependent Radiative Transfer Calculations using Diffusion Approximation

  • Noh, Tae-Wan
    • Proceedings of the Korean Nuclear Society Conference
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    • 2004.10a
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    • pp.151-152
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    • 2004
  • An acceleration technique combined with the discrete ordinates method which has been widely used in the solution of neutron transport phenomena is applied to the solution of radiative transfer equation. The self-adjoint form of the second order radiation intensity equation is used to enhance the stability of the solution, and a new linearization method is developed to avoid the nonlinearity of the material temperature equation. This new acceleration method is applied to the well known Marshak wave problem, and the numerical result is compared with that of a non-accelerated calculation

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Monte Carlo Simulation of Phonon Transport in One-Dimensional Transient Conduction and ESD Event (1 차원 과도 전도와 정전기 방전 현상에 관한 포논 전달의 몬테 카를로 모사)

  • Oh, Jang-Hyun;Lee, Joon-Sik
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2165-2170
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    • 2007
  • At nanoscales, the Boltzmann transport equation (BTE) can best describe the behavior of phonons which are energy carriers in crystalline materials. Through this study, the phonon transport in some micro/nanoscale problems was simulated with the Monte Carlo method which is a kind of the stochastic approach to the BTE. In the Monte Carlo method, the superparticles of which the number is the weighted value to the actual number of phonons are allowed to drift and be scattered by other ones based on the scattering probability. Accounting for the phonon dispersion relation and polarizations, we have confirmed the one-dimensional transient phonon transport in ballistic and diffusion limits, respectively. The thermal conductivity for GaAs was also calculated from the kinetic theory by using the proposed model. Besides, we simulated the electrostatic discharge event in the NMOS transistor as a two-dimensional problem by applying the Monte Carlo method.

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TEMPERATURE-EXPLICIT FORMULATION OF ENERGY EQUATION FOR A HEAT TRANSFER ANALYSIS (열유동 해석을 위한 에너지 방정식의 온도에 현시적인 이산화 기법)

  • Kim, Jong-Tae;Kim, Sang-Baik
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.277-282
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    • 2009
  • A temperature equation which is derived from an enthalpy transport equation by using an assumption of a constant specific heat is very attractive for analyses of heat and fluid flows. It can be used for an analysis of a solid-fluid conjugate heat transfer, and it does not need a numerical method to find temperature from a temperature-enthalpy relation. But its application is limited because of the assumption. A new method is derived in this study, which is a temperature-explicit formulation of the energy equation. The enthalpy form of the energy equation is used in the method. But the final discrete form of the equation is expressed with temperature. It can be used for a solid-fluid conjugate heat transfer and multiphase flows. It is found by numerical tests that it is very efficient and as accurate as the standard enthalpy formulation.

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Eulerian-Lagrangian Modeling of One-Dimensional Dispersion Equation in Nonuniform Flow (부등류조건에서 종확산방정식의 Eulerian-Lagrangian 모형)

  • 김대근;서일원
    • Journal of Environmental Science International
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    • v.11 no.9
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    • pp.907-914
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    • 2002
  • Various Eulerian-Lagrangian models for the one-dimensional longitudinal dispersion equation in nonuniform flow were studied comparatively. In the models studied, the transport equation was decoupled into two component parts by the operator-splitting approach; one part is governing advection and the other is governing dispersion. The advection equation has been solved by using the method of characteristics following fluid particles along the characteristic line and the results were interpolated onto an Eulerian grid on which the dispersion equation was solved by Crank-Nicholson type finite difference method. In the solution of the advection equation, Lagrange fifth, cubic spline, Hermite third and fifth interpolating polynomials were tested by numerical experiment and theoretical error analysis. Among these, Hermite interpolating polynomials are generally superior to Lagrange and cubic spline interpolating polynomials in reducing both dissipation and dispersion errors.

Numerical Modeling of One-Dimensional Longitudinal Dispersion Equation using Eulerian Method

  • Seo, Il-Won;Kim, Dae-Geun
    • Korean Journal of Hydrosciences
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    • v.6
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    • pp.51-66
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    • 1995
  • Various Eulerian-Lagerangian numerical models for the one-dimensional longtudinal dispersion equation are studied comparatively. In the models studied, the transport equation is decoupled into two component parts by the operator-splitting approach ; one part governing advection and the other dispersion. The advection equation has been solved using the method of characteristics following flud particles along the characteristic line and the result are interpolated onto an Eulerian grid on which the dispersion equation is solved by Crank-Nicholson type finite difference method. In solving the advection equation, various interpolation schemes are tested. Among those, Hermite interpo;ation po;ynomials are superor to Lagrange interpolation polynomials in reducing both dissipation and dispersion errors.

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Analysis of Contaminant Transport in the Ground using the Lattice-Boltzmann Method (격자 볼츠만 방법에 의한 지반 내 오염물질의 거동 분석)

  • Kang, Dong Hun;Yun, Tae Sup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6C
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    • pp.267-274
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    • 2012
  • The conventional approach to evaluate the contaminant transport in soils adopts the macro-scale implementation while the pore configuration and network is a dominant factor to determine the fate of contaminant. However, the observation of fate and transport at pore scale may not be readily approachable because of the computational expenses to solve Navier-Stokes equation. We herein present the 2D Lattice-Boltzmann method that enables to assess the local fluid velocity and density efficiently for the case of single phase and multi-components. The solute fate spatio-temperal space is explicitly determined by the advection of fluid flow. Two different types of idealized pore space provides the path of fluid. Also, solute transport, the velocity field and average concentration of solute are computed in steady state. Results show that the pore geometry such as tortuosity mainly affect the solute fate. It highlights the significance of the pore configuration and shape in granular soils and rock discontinuity in spite of the equivalent porosity.

Simulation on Contaminant Transport in the Aquifer Affected by River Stage (하천 수위의 영향을 받는 대수층에서 오염원의 이동에 관한 모의실험)

  • 김민환
    • Journal of the Korean Society of Groundwater Environment
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    • v.4 no.1
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    • pp.54-59
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    • 1997
  • The river and groundwater are contaminated by pollution source of a waste landfill and others near river. The contaminant transport and response of aquifer parameters are studied in the aquifer affected by variation of river stage. First, the equation for component of variation velocity with river stage is developed by using the analytical solution of groundwater governing equation. The numerical model which considered component of variation velocity is constructed for the transport of mass by advection and dispersion. In order to verify a numerical scheme, the analytical solution is used. The numerical solution is coincided with the analytical one. Aquifer parameters of Nanjido are used as the data for numerical experiment. Second, the range of aquifer parameters is established in order to reponse contaminant transport in aquifer with river stage. The result of numerical experiment shows that the range of the storage coefficient except hydraulic conductivity and effective porosity is relatively sensitive to the contaminant transport. When the storage coefficient is the order of 10$\^$-2/, the response is very sensitive to the variation of river stage.

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