From: ames!FNALD.FNAL.GOV!DROEGE
Subject: Studying Calibration Problems
Reply-To: ames!FNALD.FNAL.GOV!DROEGE
Organization: Sci.physics.fusion/Mail Gateway
Date: Wed, 14 Oct 1992 20:51:06 GMT

Thanks to all of you for the expressions of sympathy.  I did actually not get 
drunk as previous experience has taught me that that is not a good solution.  
I did pet the cat a lot.  

Don Beal has suggested that diffusing D/H from the cell might be getting to 
the Bismuth Telluride thermoelectric devices (TED) and causing a change in 
their refrigeration coefficient.  I at first said that I did not think so as 
they were behind about 1/2" of aluminum and a lot of epoxy.  I have since 
studied the design of the calorimeter and found that if there is excess 
hydrogen produced inside the dewar (remember it has to diffuse through a mm of 
polycarbonate cell wall to get there) that its path to the outside not only 
takes it by the TED but *through* them.  (A TED looks like a lot of little 
pillars of crystalline stuff supported between two ceramic plates.  There is 
lots of open space between the pillars.)  If I had wanted to expose the TED to 
gas diffusing out of the cell, I could not have done a better job. 

But I still think this is straw grasping.  It is hard to imagine that the D/H 
will hang around long enough to diffuse into the Bismuth Telluride unless it 
somehow really wants to do so.  How about it out there, does any one know if 
Bismuth Telluride would want to absorb H/D?  What is a good Hydrogen barrier?
i.e. Gold Plating?  Nickel Plating?  Palladium Plating (Ha!)?  We could do any 
of these.  What plastics are good Hydrogen barriers?  

By the way, the cell (polycarobonate) developed a crack well above the 
electrolyte line and in the vicinity of the catalyst.  But I know that this 
happened near the end of the run between the addition of the Al solution and 
the Boric Acid solution.  It looks like a stress crack, and may have been 
promoted by my running at high current (and thus high catalyst heat) near the 
end of the run.  Or it may have been weakened by the hot hydrogen (max 75 C) 
environment.  The alternative cell material is polypropylene and I will 
probably use that for near future runs.  Since I am planning a next generation 
device, I need all the advice I can get at this time.  Likely design to use 
teflon cells for the next run.  Teflon tubes do not seem to come in the size 
that the present calorimeter is designed to use.  

To all of you who will say why don't you just expose a TED to hydrogen and 
measure its change in efficiency, it is not so easy.  My device is probably 
the one thing that could do the experiment.  Remember we are considering the 
possibility of a 0.8% change in a month.  From time to time I have thought of 
peddling my machine to TED makers as a means of testing their devices.  But it 
is not a big industry.  I will probably try to do the experiment.  

Please remember out there, if I find something wrong with an experiment I 
scrap it.  I am taking a conservative position.  But I am allowing you all to 
look over my shoulder.  If you act on my preliminary results you do so at your 
own risk.  I would have published this result if the ending calibration had 
indicated that the calorimeter was drift free.  I have still seen enough 
positive looking results to keep working.  

Tom Droege

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