"This paper attempts to describe the nature of Zambia's demographic situation, which eventually led to the formulation of a national population policy; the policy instrument; and some of the measures necessary for the effective implementation of the policy....[The] situation is characterised by three dominant features: a high rate of natural increase, massive urbanisation, and wide variations ...

In the current research project, the thermal performance of a series of newly designed mixers has been investigated. Each mixer has two concentric cylinders comprising two annular slot flow channels around a solid cylindrical rod at the center. In each mixer, the first cylinder around the central solid rod has either spherical or pyramidal protrusions throughout the outer surface. It has been o...

In this paper, natural convection heat transfer over a vertical plate in a Darcy porous medium saturated with a nanofluid subject to heat generation/absorption was theoretically studied. The governing partial differential equations were transformed to a set of ordinary differential equations using similarity transformations and solved using finite difference method. The influence of parametric ...

Heat exchangers are the important equipments with a variety of industrial applications including power plants, chemical, refrigeration and air conditioning industries. Helically coiled heat exchangers are used in order to obtain a large heat transfer area per unit volume and to enhance the heat transfer coefficient on the inside surface. This paper deals with the CFD simulation of helical coile...

Abstract: During solidification and casting in metallic molds, the heat flow is controlled by the thermal resistance at the casting-mold interface. Thus heat transfer coefficient at the metal- mold interface has a predominant effect on the rate of heat transfer. In some processes such as low pressure and die-casting, the effect of pressure on molten metal will affect the rate of heat transfer a...

This work experimentally studied the convective flow and heat transfer characteristics of a novel nanostructured heat transfer fluid: "ethanol/polyalphaolefin nanoemulsion" flowing through 12 circular minichannels of 1-mm diameter each. Ethanol/polyalphaolefin nanoemulsion is a thermodynamically stable system formed by dispersing ethanol into a mixture of "polyalphaolefin (PAO)" and surfactants...

Capacity and efficiency of any refrigerating system diminish rapidly as the difference between the evaporating and condensing temperature is increased by reduction in the evaporator temperature. The single stage vapour compression refrigeration system is limited to an evaporator temperature of -40 C. Below temperature of -40 C the either cascade refrigeration system or multi stage vapour compre...

a thermodynamic analysis of the counter flow wet cooling tower (cwct) in the steelmaking unit of the khuzestan steel company (ksc) is performed in this paper. we evaluated both energy and exergy formulations for analyzing the heat and mass transfer, exergy and second-law efficiency in this cooling tower. the lewis factor le f is an indication of the relative rates of heat and mass transfer in a...

Demand for high-performance cooling systems is one of the most challenging and virtual issues in the industry and Pulsating heat pipes are effective solutions for this concern. In the present study, the best predictor correlations of flow boiling and condensation are taken into account to model a single turn pulsating heat pipe mathematically. These considerations, result in derivation of more ...