|
Principles |
Updated 04-Aug-10 21:36h
Our work is based on mathematical solutions of sand sedimentation we materialized in the development of two major instruments:
For sedimentation of individual particles, we found a general mathematical relationship among the variables involved in particle sedimentation in a fluid. We defined the drag coefficient of the sedimenting particles as a function of their Reynolds' number and Corey's Shape Factor. This function enables the explicit calculation of any involved variable, such as particle size, particle settling velocity, particle density, particle hydrodynamic shape, etc. (J. Brezina, 1979b).
Our data processing program SedVar™ computes the variables numerically using the Newton-Raphson convergence. Recently, John M. BRUDOWSKY (2006) has developed algebraic solutions of our equations by solving derived quartic equations.
For stratified sedimentation of more sand-sized particles, we determined empirically the maximum particle concentration at which the particle settling velocities are not influenced by collective sedimentation (J. Brezina, 1971b, 1972a). This enables using samples which sediment as their individual particles would do.
The relatively small sample size sets high requirements for the Analyzer's weighing capability: high sensitivity, high S/N (signal to noise) ratio, and fast response (in milliseconds).