4/3/97
I am Candace Haigler, Director of the EM Lab at Texas Tech University,
writing this message together with Mark Grimson, EM Technician, who is a
member of your Internet group. We find ourselves facing a potential
problem about which we need your advice.
Our EM lab is now fairly stable, being purpose-built underground as an
attachment to the main Biology building (it sticks out beyond the
above-ground footprint of the building). Our only current problem is that
our roof is a brick patio that attracts skate-boarders. When they are
skate-boarding, we cannot take pictures due to vibrations, but this is a
sporadic problem and we can chase them away.
Now we find that the university is making a Master Plan, the draft of which
shows a major service road to a new 1000 space parking deck coming very
close to our building. We estimate that the road will be within 50 feet,
or even closer, to the below-ground EM lab. Given our existing problem
with skate boarders, we are very worried that this road will essentially
destroy the utility of the lab.
We solicit your help in:
(1) Sharing knowledge about similar situations
(2) Pointing us to the best published sources about EM lab design,
particularly in regard to vibration and preferred distance from nearby roads
(3) Pointing us to any expert EM lab design firms from whom we
might get information
We are very concerned about this situation, and will greatly appreciate
your help. You may reply to Mark at the address shown above, or my
personal e-mail address is brchh@ttu.edu.
Sincerely,
Candace Haigler
Professor and Director of the Electron Microscopy Laboratory
brmjg@ttacs1.ttu.edu
This sounds like a real disaster in the making. Our facility is
several hundred meters from some major roads, and we were quite worried
about vibrations from truck traffic. The effects of traffic depend crit-
ically on the nature of the soil between you and the road. Bedrock will
transmit vibrations very well; whereas damp clay will absorb much of the
energy. The good news is that there may not be much traffic except for
a few times during the day, and that you may be able to convince the
university to put some vibration-damping material at the bottom of the
roadbed. I don't know what is available, but maybe a layer of poly-
urethane (which is a good vibration absorber) could be cost-effective
solution--especially if there is a source of recycled plastic locally.
Good luck.
illiam Tivol
tivol@wadsworth.org
We here at Dow are in a well-isolated facility which is a result of
demonstrating that passing trucks would give problems to our NMR
spectrometers and microscopes. Without going into the full explanation,
the argument was made based on empirical data: We had large trucks
rumble by our existing facilities during data acquisition and compared
the results to the same experiment run during a known quiet time. The
loss of information was documented and recast in terms of monetary cost
for reduced data quality. In our case, the financial penalty of reduced
resolution/sensitivity justified the extra cost of closing a major local
thoroughfare.
My suggestion would be to get someone from a trucking company to come by
and drive their truck in the approximate location of the service drive
to document the problems, then see if the U. can come up with an
alternate access route to the ramp (moving the entire ramp would be
better, but probably less likely). The fact that you have a few hundred
thousand dollars tied up in sensitive equipment suggests that the U.
recognizes the value of your work and would hopefully be willing to
accommodate the situation. Consider the bad press they would get for
compromising their research reputation in the name of a car park!
Good luck,
Bill Heeschen
waheeschen@dow.com
to guide you. 209 474-5284
Also check Chapter 1, Setting Up An Electron Microscope Facility in
Procedures in Electron Microscopy, AW Robards and AJ Wilson, eds, John
Wiley & Sons, New York. While it doesn't address skateboarders and roads
per se, it may give you ammunition to fight the administration.
Sara E. Miller, Ph. D.
P. O. Box 3020
Duke University Medical Center
Durham, NC 27710
Ph: 919 684-3452
FAX: 919 684-8735
saram@acpub.duke.edu
detect the vibration from the trains when they were around a kilometre off.
The problem will vary according to the soil type between your lab and the
new road. Ideally the road would be on swampy ground and your lab on a
platfrom carved out of granite. That would give good decoupling. But
basically, any effective solution in you laboratory will cost several
thousands per instrument, as each instrument will need to be relocated on
some heavy support (thick steel plate, thicker concrete slab, mass is what
you need) with some very flexible mounts under it (air-springs are ideal).
It may be more cost effective to route the road further away.
The classic reference work is "Design of the Electron Microscope Laboratory"
by Ronald H Alderson 1975. It is Volume 4 in "Practical Methods in Electron
Microscopy" Editor Audrey M Glauert. American Elsevier ISBN 0444 1087 6.
Was still available two years back whem I bought my second copy to share
with the architect for my new laboratory. Pages 68-86 deal with mechanical
vibration and decoupling/damping systems
Melvyn Dickson
M.Dickson@unsw.edu.au
Many years ago JEOL News published an article on the design of
the EM rooms at the John Innes Institute in the UK. As far as I
can recall this dealt in some detail with vibration
transmission. We based the design of our EM rooms on this and we
have had no vibration problems.
Robin H Cross
Director : EM Unit, Rhodes University, Grahamstown, South Africa
eurc@giraffe.ru.ac.za - tel: +27 461 318168 - fax: +27 461 24377
due to ground vibrations than to the creation of a transient magnetic field
problem that correlated with the passage of a train. In about 1969, there
was an SEM installed at a Philadelphia university near the main passenger
line of AMRAK and Conrail, and the real problem was more related to the
magnetic field (trains were pantograph (electrically) powered) than to
vibrations. The problem was ultimately "solved" only by moving the
microscope. So don't forget the magnetic field problem potential as well.
Charles A. Garber, Ph. D. Ph: 1-(610)-436-5400
President 1-(800)-2424-SPI
SPI SUPPLIES FAX: 1-(610)-436-5755
PO BOX 656 e-mail: cgarber@2spi.com
West Chester, PA 19381-0656 USA Cust. Service: spi2spi@2spi.com
Eastern Europe a number of years back. There were continual, intermittent
resolution and noise problems, worse during the day, not too often at night
and after midnight, the problems disappeared.
After a lot of investigations, the problems was finally traced to the local
trams. What was happening was that everything was OK until the trams
reached a nearby hill - the extra load in pulling up the hill (trams going
down the hill weren't a problem) dragged the mains supply voltage below an
acceptable level and caused a whole series of instabilities in the EM.
Dr L. P. Stoter Technical Editor, MICROSCOPY & ANALYSIS
Technesis
17, Rocks Park Road email: LPS@teknesis.demon.co.uk
Uckfield, E. Sussex Phone: +44 (0)1825 766911
TN22 2AT Fax: +44 (0)1825 766911
United Kingdom
phone, FAX, e-mail, www address, etc.) for vendors of vibration isolation
pads and platforms. I have a new stereo microscope installation that is
being bothered by building vibrations.
Larry Sutter
Michigan Technological University
Dept. of Civil and Environmental Engineering
1400 Townsend Dr.
Houghton, MI 49931
voice: 906-487-2423
FAX: 906-487-2943
e-mail: llsutter@mtu.edu
Get a 2 ft (or so) square of paving cement from a garden supply (or hardware
) company. Buy 4 tennis balls. Put the slab on some sturdy bench with a
tennis ball under each corner. Put the microscope on the slab. For a more
compliant isolator use a small inner tube from some small wheel.
Mel Dickson
M.Dickson@unsw.edu.au