Date: Sun, 29 Nov 1998 17:39:31 -0500 (EST)
From: [EMAIL PROTECTED]
Tom Cichoracki -
Your application sounds similar to a refiner study that I worked on as a
consultant a few years back at the Domtar paper mill in Quebec, on behalf of
PAPRICAN. In this case, wood chips are forced into the space between a flat
rotor and stator plates, each having radial grooves, and the relative motion
between the plates (and grooves) provides the forces required to "rip" the
individual wood fibers from the parent, to produce pulp for the paper making
process. The complex in-process movements of the fibers, the "ripping action"
and the relationships to the relative groove patterns were of particular
interest. "Seeing, lighting, and imaging" (cast iron housing and steel plates)
problems were very similar to what you suggested in your application.
In our research, I employed three techniques in order to gather varied
insights into the pulping process. 1) My Imacon image converter camera with
light provided by a long-duration strobe. Sequences of ten to 18 images each
were taken at 100,000 and 10 million F/S, with individual exposure times of
approximately 1/5 the interframe period. Rates this high are required to
resolve critical stages of the process, which typically occur during a period
which is very short compared, for example, to the interframe times of most
cameras. 2) My Hycam camera operating at 6,000 to 8,000 PPS with illumination
supplied by a high-powered, high-frequency stroboscope (EG&G 501) to provide
the ample light for exposure at a duration of 1 microsecond for motion
stopping. This allows one to follow particles in a comples flow pattern
without ambiguities. 3) A technique I developed in the 1960's which I call
"High-speed sampling cinematography", a combination of a strobe and low-speed
motion picture camera with the special synchronization between them and the
subject which produces high quality image sequences emulating those from movie
cameras operating up to millions of frames/sec. ("Using stroboscopy for stop
action study of high-speed events", Machine Design, April 30 and May 14,
1970). I built several video systems using this principle as solid state frame
transfer cameras became available. This technique, similar to some of the
other suggestions made to you, yields statistical information about most
subjects, though the ability to "phase slowly through" an area of mechanical
interaction in a slow and controlled manner proved to be very useful.
The cost of much of the equipment which has been suggested to you, including
the above, is quite high. Another suggestion therefore, is to consider
bringing your apparatus to some convenient location where the more promising
techniques could be tried at minimum cost, before deciding upon the
appropriateness of any given solution, if you anticipate buying or leasing
equipment for a long-term research project. If you are primarily interested in
immediate results (insights), e.g. to solve a specific problem, then use of a
consultant who comes equipped will be far cheaper.
Best of luck,
Charles Miller
MIT (Retired)
P. O. Box 160
Carlisle MA 01741-0160 USA
978-369-7074
[EMAIL PROTECTED]
or:
[EMAIL PROTECTED]
