• International Journal of Aeronautical and Space Sciences
• /
• 제9권1호
• /
• pp.1-30
• /
• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제6권
• /
• pp.14-26
• /
• 1998

This paper deals with approximate analytical solutions for the two-region one-dimensional model describing the charging process of stratified thermal storage tanks at variable inlet temperature with momentum-induced mixing. An arbitrarily increasing inlet temperature is decomposed into inherent step changes and intervals of continuous change. Each continuous interval is approximated as a finite number of piecewise linear functions, which admits an analytical solution for perfectly mixed region. Using the Laplace transform, the temperature profiles in plug flow region with both the semi-infinite and adiabatic ends are successfully derived in terms of well-defined functions. The effect of end condition on the solution proves to be negligible under the practical operating conditions. For a Quadratic variation of inlet temperature, the approximate solution employing a moderate number of pieces agrees excellently with the exact solution.

• Journal of Applied Biological Chemistry
• /
• 제55권2호
• /
• pp.79-83
• /
• 2012

벼의 발아에서부터 생장 결실기에까지 토양, 온도, 시비조건 등의 재배환경은 벼에 발현되는 단백질체의 profile을 변화시키는 것이 잘 알려져 있다. 온도를 포함한 재배환경이 다른 경상북도 칠곡과 강원도 출원에서 재배된 오대 백미의 단백질체 profile을 2-dimensional (D) gel 상에서 분리하여 비교함으로써 재배환경에 의해 현저하게 발현양의 차이를 보이는 단백질들의 기능을 분석하였다. 오대 백미에 발현되는 112개의 단백질들의 기능을 고려할 때 재배환경에 의해 가장 유의적인 차이를 보이는 단백질 군들은 철원 오대백미의 스트레스 대응 단백질로 지베렐린 합성에 관여하는 ent-kaur-16-ene synthase이며 칠곡 오대백미의 스트레스 대응 단백질은 heat shock protein으로 재배환경에 따라 발현되는 스트레스 대응 단백질의 종류도 다르게 나타났다. 등숙온도가 높은 칠곡에서 재배된 오대 백미에는 곰팡이나 Bacillus 병원균에 대응하는 xylanase inhibitor protein이 유의적으로 발현되었으며, 철원 백미에서는 세포벽 합성관련 효소, 세포주기 관련 단백질 등이 선별적으로 발현의 증가를 보였고 수송관여 단백질들은 철원 및 칠곡 백미에서 모두 변화를 보였다. 단백질 함량과 단백질 profile을 종합적으로 분석할 때 철원 백미에는 칠곡 백미에 비해 새로운 주종 단백질들의 발현이 많았으며 칠곡 백미는 전체적인 단백질의 발현이 높게 나타났음을 보여, 재배환경에 따라 단백질 profile이 변화되는 특성이 다름을 보였는데, 이 결과는 지구온난화와 같은 기후 변화에 따른 작물의 단백질체 변화와 고급미 생산을 위해 적절한 단백질체 profile을 갖게 하는 재배조건 확립 등의 연구에 활용될 수 있다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2000년도 추계 학술대회지
• /
• pp.236-237
• /
• 2000

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
• /
• pp.225-226
• /
• 2003

• Journal of Computational Design and Engineering
• /
• 제3권4호
• /
• pp.349-362
• /
• 2016

The numerical solutions of unsteady hydromagnetic natural convection Couette flow of a viscous, incompressible and electrically conducting fluid between the two vertical parallel plates in the presence of thermal radiation, thermal diffusion and diffusion thermo are obtained here. The fundamental dimensionless governing coupled linear partial differential equations for impulsive movement and uniformly accelerated movement of the plate were solved by an efficient Finite Element Method. Computations were performed for a wide range of the governing flow parameters, viz., Thermal diffusion (Soret) and Diffusion thermo (Dufour) parameters, Magnetic field parameter, Prandtl number, Thermal radiation and Schmidt number. The effects of these flow parameters on the velocity (u), temperature (${\theta}$) and Concentration (${\phi}$) are shown graphically. Also the effects of these pertinent parameters on the skin-friction, the rate of heat and mass transfer are obtained and discussed numerically through tabular forms. These are in good agreement with earlier reported studies. Analysis indicates that the fluid velocity is an increasing function of Grashof numbers for heat and mass transfer, Soret and Dufour numbers whereas the Magnetic parameter, Thermal radiation parameter, Prandtl number and Schmidt number lead to reduction of the velocity profiles. Also, it is noticed that the rate of heat transfer coefficient and temperature profiles increase with decrease in the thermal radiation parameter and Prandtl number, whereas the reverse effect is observed with increase of Dufour number. Further, the concentration profiles increase with increase in the Soret number whereas reverse effect is seen by increasing the values of the Schmidt number.

• ETRI Journal
• /
• 제19권2호
• /
• pp.59-70
• /
• 1997

A study on the operation of a heat pipe with two heat sources has been performed to optimize the heat distribution of satellite equipment. A numerical modeling is used to predict the temperature profile for the heat pipe assuming cylindrical two-dimensional laminar flow for the vapor, and the conduction heat transfer for the wall and wick. An experimental study using the copper-water heat pipe with the length of 0.45 m has been performed to evaluate the numerical model and to compare the temperature distribution at the outer wall for the non-uniform heat distribution. The results on temperature profiles for the heat input range from 29 W to 47 W on each heater are presented. Also the correlation between the heat input and the temperature increase is presented for the optimum distribution on two heaters. The result shows that the outer wall temperature can be controlled by redistribution of heat sources. It is also concluded that the heat source closer to the condenser can carry more heat while maintaining lower temperatures at the outer wall.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2001년도 추계 학술대회논문집
• /
• pp.31-36
• /
• 2001

The velocity and temperature profiles in the cabin of the automobile affect greatly to the comfort of the passenger. In this paper, the three dimensional flow and temperature analysis in the cabin of the automobile which is geometrically complicated was performed to investigate and predict the velocity and temperature profile. The three dimensional Navier-Stokes code used in this case was validated by performing of a 1/5 experimental scale model vehicle flow anal)rsis successfully. The temperature field of cavity was analyzed for Energy-equation code validation. The comparison of the results are made with the polished computational data and give a coincided one.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1999년도 춘계학술발표회요약집
• /
• pp.107-107
• /
• 1999

Direct-contact condensation experiments of atmospheric steam and steam/air mixture on subcooled water flowing co-currently in a rectangular channel are carried out uszng an infrared thermal camera system to develop a temperature measurement method. The inframetrics Model 760 Infrared Thermal Imaging Radiometer is used for the measurement of the temperature field of the water film for various flow conditions. The local heat transfer coefficient is calculated using the bulk temperature gradient along the (low direction. It is also found that the temperature profiles can be used to understand the interfacial condensation heat transfer characteristics according to the flow conditions such as noncondensable gas effects, inclination effect, and flow rates.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2254-2255
• /
• 2008

Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products, but temperature difference between surface and center of sheet is difficult to decrease because of low thermal conductivity of ABS material. In order to decrease temperature difference between surface and center, heating profile must be expressed as exponential function form. In this study, Finite Difference Method was used to find out the coefficients of optimal heating profiles. Through investigation, the optimal results using Finite Difference Method show that temperature difference between surface and center of sheet can be remarkably minimized with satisfying Temperature of Forming Window.