helical coil heat exchangers are widely used in industrial applications ranging fromcryogenic processes, air-conditioning, and nuclear reactors to waste heat recovery due totheir compact size and high heat transfer coefficient. in this kind of heat exchangers, flowand heat transfer are complicated. this paper reports a numerical investigation of theinfluence of different parameters such as coil...

This thesis will investigate the advection and diffusion of a passive scalar in helical pipes. By assuming that the curvature and torsion are small (equivalent to small Dean number) and the Reynolds number is moderate, one can use a closed form approximation, due to Dean (1927) and Germano (1982), for the induced recirculation. Using a simulation developed this summer, the problem will be inves...

Introduction Landsat Thematic Mapper ( TM ) imagery was used to analyze patterns of landscape diversity in the seasonal tropical forests of northeastern Guatemala. TM radiance and the radiance coefficient of variation (CV) were significant in discriminating land-cover types. Cluster analysis of TM4, TM5, and TM7 radiance produced six distinct types of landcover. Green leaf biomass from TM4 and ...

This article examines the impact of cognitive skills on the income of households in Ghana. It uses scores on mathematics and English tests to measure cognitive skills and estimates the returns to these skills based on farm profit, off-farm income, and total income. The article uses Powell’s censored least absolute deviations and symmetrically trimmed least squares estimators to estimate farm an...

Two-fluid Dean vortex flow in a coiled pipe with vanishing torsion, and its effect on the mass transfer through the liquid–liquid interface of two immiscible fluids are studied numerically. The liquids are stratified by gravity, with the denser one occupying the lower part of the pipe. The Navier–Stokes equations in both fluid layers are solved numerically by the finite volume method. The resul...