From: ames!FNALD.FNAL.GOV!DROEGE
Subject: Possible Gas Absorption Experiments
Reply-To: ames!FNALD.FNAL.GOV!DROEGE
Organization: Sci.physics.fusion/Mail Gateway
Date: Mon, 14 Sep 1992 22:58:32 GMT

Frank Smith has nicely typed in a lot of material from the Flanagan et al.
article on the calorimetry of Deuterium absorption in Pd.  Thank you Frank.

Sorry I can not yet reproduce Franks word's with all those <><>< that everyone 
else seems to use.  Frank's comments were in FD-473 14 Sept 92 00:05:57 GMT.
Since the subject may have common interest is posted here instead of a private
message to Frank.  

My interest is to try to decide if there is a useful measurement that I can 
make with my machine.  

I understand the experiment and the apparatus.  It looks very nice.  

One thing missing from Frank's summary are error limits on the measurement.  
Since by my estimate they generate about 5000 joules in 10 minutes, this is a 
power level of order 10 watts and they should be able to measure this to 0.1% 
with their type of calorimeter.  What I do not understand, is how they know 
the D/Pd ratio very accurately since it seems to be done with a pressure 
measurement.  Possibly pressure gages have kept up with electronics since I 
left school, but I doubt it.  Perhaps they heat the container after the 
experiment and measure the evolved D?  I do notice that they give the energy 
measurements to one more decimal place than the D/Pd ratios.  

One thing that I do not understand is the evolution half of the experiment.  
How is the H/D removed from the Pd so quickly?  I assume they put a vacuum in 
the dosing volume.  My experience at atmospheric pressure is that it takes 
many days for a charged sample to outgas.  I guess the thin foil is the 
answer.

While they could try to get absorption heat as a function of D/Pd ratio by 
comparing evolved heat and pressure, time lags in such a system would make it 
very difficult to unscramble the data.  I assume that they have done many 
experiments each with a different starting pressure in the dosing volume in 
order to get enthalpy of absorption as a function of D/Pd ratio.  Frank, 
please, what is the highest D/Pd ratio measured? 

One thing that I could do would be to make a continuous measurement of 
enthalpy of absorption as a single sample is charged.  The Flanagan experiment 
looks like it gives the Pd a sudden shock.  If this is damaging to the 
structure then a slow charge might give a different answer.  It seems that 
slow charging results in higher final D/Pd ratios in electrolytic cells.  

Frank, as my last post showed, I think that I understand the "factor of two" 
and it is just plain error of measurement based on the experiment not being 
done right.  The measurement includes (until I study the data and attempt to 
remove it) the heat required to raise the cell to a higher operating 
temperature.  In response to your "are you expecting too fast a response?", I 
am making the measurement much more slowly - 5 hours vs 10 min.  

The real question is - "Can I do a better experiment?"  It will be hard to 
beat their accuracy by much.  But if there are any discontinuities I might be 
able to pick them up by making a continuous run.  It is also possible that 
electrolytic charging will get to higher D/Pd ratios than they achieved and 
that a slower charge at relatively low and constant temperature will somehow 
be different than the very high temperatures that the foils undoubtedly 
reached as they were suddenly exposed to high pressure D.  I assume that the 
copper was there to distribute the heat.  

Tom Droege

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