• 제목/요약/키워드: Solution flow

검색결과 3,119건 처리시간 0.033초

Pseudomonas delafieldii가 생성하는 다당류의 레올로지 특성 (Rheological Properties of Biopolymer Produced by Pseudomonas delafieldii)

  • Yoo, Jin-Young;Chung, Dong-Hyo
    • 한국미생물·생명공학회지
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    • 제17권5호
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    • pp.475-480
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    • 1989
  • Pseudomonas delafieldii이 배양액으로부터 분리한 다당류 용액의 물성을 검토하였다. 본 다당류는 매우 점도가 높은 의가소성 물질로 1% 용액의 겉보기 점도는 42sec$^{-1}$에서 1769mpaㆍs이었다. 이 용액은 pH에 대한 안정성은 있으나 열 안정성은 보이지 않았다. 이 용액의 유동 활성에너지는 4.44kacl/mole 이고, 농도의존성은 double 1logarithm으로 포현되었다.

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Analytical Solution for Flow Field by Arbitrarily-Located Multi Injection-Pumping Wells

  • Yoo, In-Wook;Lee, Kang-Kun
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2001년도 추계학술발표회
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    • pp.79-82
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    • 2001
  • Analytical solutions have been derived to delineate the capture zone created by pumping wells for the remediation design of contaminated groundwater. These previous analytical solutions are often restricted to pumping wells only, specific well locations, a limited number of wells, and an isotropic aquifer. Analytical solution was developed to deal with arbitrarily located multi injection-pumping wells in an anisotropic homogeneous aquifer. The solution presented in this study provides a simple, easy method for determining tile complex flow field caused by multi injection-pumping wells at different rates, and will consequently be useful in pump-and-treat design.

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속도차를 갖는 두 회전판에 의해 유도되는 원통 내부 유동 (Flows in a confined cylindrical container with differential rotating top and bottom disks)

  • 박준상
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 춘계학술대회논문집
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    • pp.487-490
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    • 2008
  • A theoretical study is made of the flow in a confined cylindrical container with differential rotating top and bottom disks. Two kinds of theoretical solution for the azimuthal velocity were obtained: one is an exact solution of Bessel function type and the other is an approximate solution of exponential function type which comes from WKB approximation. Both theoretical solutions are shown to be self consistent with each other as well as a good agreement with previous studies. Moreover, in a range of relatively low Reynolds number, the obtained solution of Bessel function type shows better result than previous solutions.

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하수처리수 이용 흡수식 열펌프 사이클의 시뮬레이션 (Simulation of a two-stage absorption heat pump cycle using treated sewage)

  • 이용화;신현준;최국광
    • 설비공학논문집
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    • 제11권3호
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    • pp.422-430
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    • 1999
  • This paper concerns the study of a two-stage absorption heat pump cycle to utilize treated sewage. This two-stage cycle consists of coupling double-effect with parallel or series flow type and single effect cycle so that the first stage absorber and condenser produces hot water to evaporate refrigerant in the evaporator of the second stage. The effects of operating variables such as absorber temperature on the coefficient of performance have been studied for two-stage absorption heat pump cycle. The working fluid is lithium bromide and water solution. The efficiency of the two-stage absorption heat pump cycle has been studied and simulation results show that higher coefficient of performance could be obtained for the first stage with parallel flow type. The optimum ratio of solution distribution can be shown by considering the COP, the crystallization of solution and the generator temperature.

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전력계통해석을 위한 Non-Divergent 조류계산의 실용적 적용 (Practical application of NDPF solution in power system analysis)

  • 국경수;이정호;문영환;김호용;오태규
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.136-138
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    • 2003
  • This paper describes the practical application of Non-Divergent Power Flow (NDPF) solution in power system analysis. NDPF algorithm prevents the power flow solution from diverging due to the arithmetic error in Newton method, and indicates voltage collapse point. In addition to that, NDPF solution provides us with useful information for evaluating voltage profile in such cases.

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최소비용문제의 퇴화 정점 최적해에 대한 감도분석 (Sensitivity Analysis on the Degenerate Tree Solution of the Minimum Cost Flow Problem)

  • 정호연;박순달
    • 산업공학
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    • 제7권3호
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    • pp.193-199
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    • 1994
  • The purpose of this paper is to develop a method of the sensitivity analysis that can be applicable to a degenerate tree solution of the minimum cost flow problem. First, we introduce two types of sensitivity analysis. A sensitivity analysis of Type 1 is the well known method applicable to a spanning tree solution. However, this method have some difficulties in case of being applied to a degenerate tree solution. So we propose a sensitivity analysis of Type 2 that keeps solutions of upper bounds remaining at upper bounds, those of lower bounds at lower bounds, and those of intermediate values at intermediate values. For the cost coefficient, we present a method that the sensitivity analysis of Type 2 is solved by using the method of a sensitivity analysis of Type 1. Besides we also show that the results of sensitivity analysis of Type 2 are union set of those of Type 1 sensitivity analysis. For the right-hand side constant or the capacity, we present a simple method for the sensitivity analysis of Type 2 which uses arcs with intermediate values.

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Experimental Study on Heat and Mass transfer Coefficient Comparison Between Counterflow Types and Parallel in Packed Tower of Dehumidification System

  • Sukmaji, I.C.;Choi, K.H.;Yohana, Eflita;Hengki R, R.;Kim, J.R.
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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    • pp.162-169
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    • 2009
  • In summer electrical energy is consumed in very high rate. It is used to operate conventional air conditioning system. Hot and humid air can germinate mould spores, encourage ill health, and create physiological stress (discomfort). Dehumidifier solar cooling effect is the one alternative solution saving electrical energy. We use surplus heat energy in the summer, to get cooling effect and then to get human reach to comfort condition. These devices have two system, dehumidifier and regeneration system. This paper will be focus in dehumidifier system. Dehumidifier system use for absorbing moisture in the air and decreasing air temperature. When the liquid desiccant as strong solution contact with the vapor air in the packed tower, it works. The heat and mass transfer performances of flow pattern in the packed tower of dehumidifier are analyzed and compared in detail. In this experiment was introduced, the flow patterns are parallel flow and counter flow. The performance of these flow patterns will calculate from air side. Which is the best flow pattern that gave huge mass transfer rate? The proposed dehumidifier flow pattern will be helpful in the design and optimization of the dehumidifier solar cooling system.

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암모니아/물 흡수식 냉동기의 판형 재생기의 수치해석 (Numerical Analysis of a Plate Type Generator for Ammonia/Water Absorption Refrigerators)

  • 지제환;정은수;정시영
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.304-310
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    • 2001
  • A numerical model which simulates the heat and mass transfer processes within a counter-current plate type generator for ammonia/water absorption refrigerators was developed. Ammonia/water solution flows downward under gravity and ammonia/water vapor generated by flow boiling flows upward. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phase were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the generator length, the wall temperature and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

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F.A.M.을 이용한 공동 내부의 유동해석 (Analysis of Flow Field in Cavity Using Finite Analytic Method)

  • 박명규;정정환;김동진
    • Journal of Advanced Marine Engineering and Technology
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    • 제15권4호
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    • pp.46-53
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    • 1991
  • In the present study, Navier-Stokes equation is numerically solved by use of a Finite analytic method to obtain the 2-dimensional flow field in the square cavity. The basic idea of F.A.M. is the incorporation of local analytic solutions in the numerical solution of linear or non-linear partial differential equations. In the F.A.M., the total problem is subdivided into a number of all elements. The local analytic solution is obtained for the small element in which the governing equation, if non-linear, to be linearized. The local analytic solutions are then expressed in algebraic form and are overlapped to cover the entire region of the problem. The assembly of these local analytic solutions, which still preserve the overall nonlinearity of the governing equations, results in a system of linear algebraic equations. The system of algebraic equations is then solved to provide the numerical solutions of the total problem. The computed flow field shows the same characteristics to physical concept of flow phenomena.

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비정상 포텐셜 유동의 패널법 해석에서 포텐셜의 2차 미분값의 수치계산 (Numerical Evaluation of 2nd Derivatives of the Potential in the Panel method for the Unsteady Potential Flow Problem)

  • 양진호;전호환
    • 한국해양공학회지
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    • 제14권3호
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    • pp.41-45
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    • 2000
  • In solving the unsteady potential flow problem of the ship in waves with the panel method, in general one can consider the basic flow as the free stream or double body solution. For the double body solution, the body boundary condition has the 2nd derivatives of the velocity potential. Low order panel methods are known to suffer from the significant error in the 2nd derivatives computed at the body surface. This paper analyzes the numerical error in the 2nd derivatives for a 2-D cylinder and a 3-D sphere problem, and an extrapolation method to obtain the correct derivatives on the body surface is suggested.

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