Search results for "Sedimentation equilibrium"

Electrical magnitudes in gravitational and centrifugal systems

1993

Abstract A new formulation to study the non-equilibrium processes in gravitational and centrifugal electrochemical systems is developed. The driving forces and the fluxes are measurable quantities. The electrical equilibrium and the pure electrical conduction are described in an evident, simple and exact manner. Theoretical expressions of the emf for several gravitational cells are shown. Some differences are observed with those given in the literature ( eg the terminals density does not appear). The electrochemical potential of ion species is the basic piece in this study.

1990

The determination of average molecular weights and the characterization of molecular weight distributions by the ratio of the weight- to number-average molecular weights Mw/Mn from sedimentation equilibrium in the ultracentrifuge are described. The essential measurement of the density profile of the mixed solvent is conducted according to Munk (Macromolecules15, 500 (1982)). Special evaluation of the polymer band in the equilibrium allowed to deduce from the observed concentration profile Mw and Mn of a series of poly(methyl methacrylate) samples and thus to characterize the molecular weight distribution of the samples.