From: Marc S. Lewis <mslewis@helix.nih.gov>
  To  : rasmb@bbri.eri.harvard.edu
  Date: Thu, 22 Jun 95 11:23:57 -0400

Re: warning xla calculations (fwd)

For the very rare velocity runs that I perform, my practice is to start at
3000 rpm while the vacuum is coming down, taking preliminary scans for
checking at this time.  I then accelerate to the final speed and use
autoscan for the rest of the scans.  After editing, the scans are analysed
by determining the square root of the second moment radius using MLAB to
fit the data to the arbitrary fitting function described in the chapter by
Attri & Lewis in the Harding, Rowe & Horton book.  The radial positions are
then fit as a function of the integral of omega-squared*time for the
appropriate scan to obtain s.  Extrapolation to zero omega-squared*time
gives good agreement with the meniscus radius.  This procedure has worked
very well and I have had no problems with it.

Marc S. Lewis

Buiding 35  Room B101C
National Institutes of Health
35 CONVENT DR MSC 4205
BETHESDA MD 20892-4205
301-496-9044 or 301-496-7220 (fax)