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Hi all -<BR>
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The issue of temperature control raised by Jack Kornblatt is an important one. The absolute temperature of the rotor is probably not defined (or claimed) to better than a few tenths of a degree, but at least once the thing has settled down the constancy seems acceptable (better than 0.1 deg usually). For most velocity work this is fine. Although if you happen to want to study the effect of varying temperature one would like to know the true temperatures, not just to have the reassurance that whatever they are, they are steady !<BR>
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As Peter Schuck says, there is no escape from pre-equilibration if you want to be really sure you have no effects caused by minor changes in temperature. However, I doubt that in most cases the <U>stability</U> of the boundary is in question if we are merely talking of the odd degree or fractions of a degree. Convective stirring is pretty unlikely. After all - temperature control systems were absent from the earliest AUCs, and people got stable boundaries and s values similar to modern ones, even with a temperature drift amounting to whole degrees !<BR>
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One can of course evaluate s values use the integral of f(T)*(omega)^2.dt in place of (omega)^2, where f(T) is the temperature correction factor at the temperature T appertaining at time t. Assuming that no component in the system shows significant temperature-dependent effects, that's valid. I recall that years ago I did this - no doubt for some good (but un-remembered) reason . . .<BR>
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Best wishes for your project, Jack - and kind regards to all on RASMB<BR>
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Arthur<BR>
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Arthur J Rowe<BR>
Professor of Biomolecular Technology<BR>
NCMH Business Centre<BR>
University of Nottingham<BR>
School of Biosciences<BR>
Sutton Bonington<BR>
Leicestershire LE12 5RD UK<BR>
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Tel: +44 (0)115 951 6156<BR>
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