The extraction device used in rotating-disk sorptive extraction consists of a Teflon disk in which a sorptive phase is fixed on one of its surfaces. Depending on the configuration, the rotation axis of the disk device can be either perpendicular or parallel to its radius, giving rise to two different mass transfer patterns when rotating-disk sorptive extraction is applied in liquid samples. In ...

Numerical calculations of vortex flows in Taylor-Couette systems with counter rotating cylinders are presented. The full, time-dependent Navier-Stokes equations are solved with a combination of a finite difference and a Galerkin method. Annular gaps of radius ratio eta=0.5 and of several heights are simulated. They are closed by nonrotating lids that produce localized Ekman vortices in their vi...

We examine the modes admitted by the Mestel disk, a disk with a globally flat rotation curve. In contrast to previous analyses of this problem by Zang (1976) and Evans & Read (1998a, 1998b), we approximate the orbits to obtain almost closed expressions for the kernel of the integral equation governing the behaviour of the modes. Otherwise we, like them, follow Kalnajs’ programme to simultaneous...

An experimental investigation on the vibrational behavior of a rotating disk by means of three optical fiber sensors is presented. The disk, which is a scale model of the real disk of an aircraft engine, was assembled in a wind tunnel in order to simulate real operation conditions. The pressure difference between the upstream and downstream sides of the disk causes an airflow that might force t...

This article focused on the stress analysis of an edge crack in a thin hallow rotating functionally graded material (FGM) disk. The disk is assumed to be isotropic with exponentially varying elastic modulus in the radial direction. A comprehensive study is carried out for various combinations of the crack length and orientation with the different gradation of materials. The effect of non-unifor...

-The unsteady similarity equations have been obtained for a disk rotating in a viscous fluid that decelerates with angular velocity proportional to time. The resulting ordinary differential equations have been solved numerically using an easy numerical technique for range 0 100    s of the non-dimensional parameter s which measures unsteadiness. The calculations have been carried out using t...

The roles of chemical kinetics and mass transfer in two types of bioreactors (packed-column reactors and rotating disk bioreactors), used with continuous-flow sample/ reagent(s) processing, are discussed in detail. A normalized quantitative comparison between these types of reactors clearly shows that rotating disk reactors afford a significantly more efficient utilization of immobilized active...

The two known exact solutions of Einstein’s field equations describing rotating objects of physical significance – a black hole and a rigidly rotating disk of dust – are discussed using a single mathematical framework related to Jacobi’s inversion problem. Both solutions can be represented in such a form that they differ in the choice of a complex parameter and a real solution of the axisymmetr...