Hamburg 2001 – scientific programme
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DY: Dynamik und Statistische Physik
DY 20: Ferrofluide I
DY 20.2: Talk
Tuesday, March 27, 2001, 09:45–10:00, S 5.5
Thermodiffusion in magnetic fluids — •Thomas Völker1, Elmars Blums2, and Stefan Odenbach1 — 1ZARM, University of Bremen, Am Fallturm, 28359 Bremen — 2Institute of Physics, University of Riga, 2169 Salaspils/Latvia
At the moment two analytical calculations for the Soret coefficient describing the separation problem exist: One is valid for the initial part of separation and the other for the steady concentration difference. Up to now the corresponding Soret coefficient is evaluated from the unsteady part of separation curves by using an empirical analysis because of limited experimental time and experimental problems at the initial part of separation. To get closer insight into this problem we have designed two independent experimental setups with identical thermodiffusion columns and measuring devices, one for long-time experiments and the other for short-time experiments. The present talk deals with experimental results of separation dynamics in the thermodiffusion column in which we reach the regime of steady concentration difference. In this state one can calculate the Soret coefficient. Furthermore we will present experimental results concerning the initial part of the separation process to compare the calculated Soret coefficient that follows from all parts of the temporal evolution of the concentration difference.