Rarefied Couette flow between concentric rotating cylinders is investigated using Maxwell’s slip-velocity boundary treatment. The study provides an independent reassessment of the velocity inversion process and demonstrates that the occurrence of an inverted velocity profile depends solely on the accommodation coefficient of the stationary outer cylinder. From the analysis, criteria are derived...

carbon nanotube, a new structure of carbon element, is composed of graphene sheets rolled into closed concentric cylinders with diameter of the order of nanometers and length of micrometers. liquid arc discharge was used for fabrication of carbon nanotubes, and subsequently a modified acid treatment method applied for purification stage. a statistical design of experimental (doe) (taguchi metho...

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

INTRODUCTION Left ventricular geometry is associated with cardiovascular events and prognosis. The Tei index of myocardial performance is a combined index of systolic and diastolic dysfunction and has been shown to be a predictor of cardiovascular outcome in heart diseases. The relationship between the Tei index and left ventricular geometry has not been well studied. This study examined the as...

The magnetoconvection phenomenon of a double diffusive free convection in an annular porous space inside two concentric cylinders saturated by (Al2O3, water) nanofluid has been investigated the current study. transport equations for vorticity, energy and concentration as well stream function are solved using finite difference method. At lower temperatures concentrations, outer cylinder is susta...