summary - water humps

Quincy Teng (teng@sunchem.chem.uga.edu)
Fri, 22 Sep 1995 11:16:20 -0400 (EDT)

summary - water humps
I have received several responds about the water hump. Most of them refer
the humps to the effect of vibration. Other possibilities are the interference
from air conditioning system (because the frequency is about 50 Hz),
temperature change. I have recorded 1H spectra of water with the flat tires
on the vibration legs (the magnet sat on floor) and with pressurized (55 psi).
There are two pairs of humps with flat tires, which have frequency separations
of ~50 Hz and 35 Hz, respectively. The 35 Hz humps can be eliminated with
pressure on, which arise from building vibration, I think. I did same
experiments using a BB probe and got same results. The other pair of humps
are from two vacuum pumps installed below the nmr lab. Those two pumps
are huge and very noise. They are on and off periodically. So, that is the
source of vibration. It is much stronger than building vibration. The 1H
spectra are available upon request.

Thanks for your help.

Quincy

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Quincy Teng, PhD
Director, Magnetic Resonance Facility
Department of Chemistry
University of Georgia
Cedar Street
Athens, GA 30602
Phone: (706)542-1321
fax: (706)542-9454
INTERNET: teng@sunchem.chem.uga.edu
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