摘要:

AbstractThe effects of Hall current on unsteady free convection flow of an MHD viscous incompressible fluid along an infinite vertical porous plate are investigated in the presence of a uniformly applied magnetic field acting in a plane which makes an angle α with the plane transverse to the plate. A similarity parameter, taken to be a function of time, is introduced, and the suction velocity is considered to be inversely proportional to this parameter. Similarity equations are then derived and solved numerically. The effects of the Hall parameter, the magnetic parameter and the permeability are discussed and shown graphically

ISSN:0363-907X    

DOI:10.1002/er.4440180902

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractSimultaneous measurements of thermal conductivity and thermal diffusivity of composite red‐sand bricks, glycerine and mercury have been made at room temperature by the recently developed transient plane source (TPS) technique. This paper describes, in brief, the theory and the experimental conditions for the simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and metals. The source of heat is a hot disc made out of bifilar spirals. The disc also serves as a sensor of temperature increase in the sample. The measured values of the thermal conductivity and thermal diffusivity of these samples are in agreement with the values reported earlier using other methods. The advantage of the TPS technique is the simplicity of the equipment, simultaneous information on thermal conductivity and thermal diffusivity, and also the applicability of the technique to insulators, fluids and metal

ISSN:0363-907X    

DOI:10.1002/er.4440180903

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe paper begins by discussing the importance of accurate estimates of the price elasticity of demand and some of the problems frequently encountered in obtaining these estimates. To these problems is added that associated with inaccuracy in the measurement of the dependent variable and one or more of the independent variables that affect the quantity demanded. Two diagnostics, i.e. the regression coefficient bounds and the bias correction factor, have been introduced to assess the effect that such measurement error has on the estimated coefficients of demand relationships. The use of these diagnostics will aid in assessing the integrity of the estimates obtained. In considering the demand for natural gas and the demand for liquefied petroleum gas by farmers in the USA, both the quantity demanded and the price data available for demand model estimation purposes contain measurement error. The regression coefficient bounds diagnostic was used to indicate a range over which the true price responsiveness of farmers to changes in energy prices lies. The results suggest that each 1% increase (decrease) in the price of energy will result in a decrease (increase) of between 0.41 and 0.17% in the quantity of natural gas demanded and a decrease (increase) of between 0.48 and 0.07% in the quantity of liquefied petroleum gas demanded. The bias correction factor was computed to evaluate the magnitude of the underestimation of the responsiveness of the quantity of natural gas and liquefied petroleum gas demanded to a change in the number of acres irrigated. For natural gas, the under‐estimation was 26.5%, whereas, for liquefied petroleum gas, it was 9.5

ISSN:0363-907X    

DOI:10.1002/er.4440180904

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA lumped parameter model has been developed to predict the liquid filmwise condensation of pure refrigerants, as well as refrigerant mixtures, inside vertical cylinder with enhanced surfaces. The mathematical formulation is based on mass, momentum and energy balance. Several constitutive relationships have been established to describe the various phenomena during condensation. Numerical results indicate that the model fairly predicted the liquid filmwise condensation phenomenon, under various conditions.

ISSN:0363-907X    

DOI:10.1002/er.4440180905

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe MHD generator is examined as a converter of the gas kinetic energy to electric power. A number of modeling assumptions allow determination of maximum power removal with the highest efficiency, both of which must be large for the MHD generator to be a practical component of a high efficiency energy conversion system. This paper identifies the optimal flow conditions and allows determination of the fraction of the flow's total enthalpy which can be removed as electric power.

ISSN:0363-907X    

DOI:10.1002/er.4440180906

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440180901

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY