Path: santra!tut!draken!kth!mcvax!uunet!shelby!decwrl!jumbo!stolfi
From: stolfi@jumbo.dec.com (Jorge Stolfi)
Newsgroups: alt.fusion
Subject: Re: What Happened in L.A.?
Summary: Blah Blah Blah Blah.
Message-ID: <13739@jumbo.dec.com>
Date: 11 May 89 09:50:26 GMT
References: <329@eplrx7.UUCP> <1482@hudson.acc.virginia.edu>
Reply-To: stolfi@src.dec.com (Jorge Stolfi)
Followup-To: alt.fusion
Organization: DEC Systems Research Center, Palo Alto
Lines: 97

Dale Bass writes:
>   
>   Apparently, Fleischmann showed a tape of a drop of indicator
>   being well mixed into the cell by convection in a time less
>   than about 20 seconds.  With these convective effects, the
>   demonstration should put questions of thermal gradients to rest
>   for good.  We can now get on to answering the important
>   question, "Is this fusion?" 

Well, maybe.

Let's have a look at F&P's original data.  I computed the following
numbers from table 1 of their article for the Journal of
Electroanalytic chemistry (the 20/Mar/89 draft that was circumfaxed
through the net): 


         Electrode      Current     Total       Excess rate of
         dimensions     density     current     heating claimed
         (cm)           (amp/cm^2)  (amperes)   (watts)  (deg.C/min)
      +----------------------------------------------------------------
      |
   1. |  0.1 x 10       0.008       0.025       0.0075   0.00086
   2. |  0.1 x 10       0.064       0.202       0.079    0.0091
   3. |  0.1 x 1.25     0.512       0.205       0.082    0.0094
      |
   4. |  0.2 x 10       0.008       0.051       0.036    0.0041
   5. |  0.2 x 10       0.064       0.404       0.493    0.057
   6. |  0.2 x 1.25     0.512       0.418       0.377    0.043
      |
   7. |  0.4 x 10       0.008       0.102       0.153    0.018
   8. |  0.4 x 10       0.064       0.812       1.751    0.201 <<<
   9. |  0.4 x 1.25     0.512       0.879       3.350    0.384 <<<
      |
  10. |  0.2 x 8 x 8    0.0008      0.010       0.000**  0.000
  11. |  0.2 x 8 x 8    0.0012      0.015       0.027    0.003
  12. |  0.2 x 8 x 8    0.0016      0.020       0.079    0.009
      |  

I hope I haven't misread the paper or bungled in the arithmetic.
(The entry marked ** was 0.153 in the paper, but that looks like a
typo, since the corresponding heat/cc is given as 0.) Note that the
numbers in the last column are *not* F&P data; I computed them from the
preceding column only to help visualize the magnitude of the claimed
effects.  I guessed the cell's internal volume as 125ml (4 cm diameter
by 10cm length), and assumed a specific heat of 4.18 joules/deg.C/gram
and a totally insulated cell. 

Now, given all the things that are or could be happening in the F&P
cell (convection, bubbling, evaporation, D+O recombination, PdH phase
changes, non-uniform electric currents, poorly-characterized electrodes
that change with time, etc.), the majority of those numbers look
rather unimpressive.  For comparison, the the six 34-watt fluorescent
lamps in my office dump some 0.015 watts into my coffe mug.  A 60-watt
desk lamp 70 cm away would dump some 0.040 watts into the same mug.
For direct sunlight the figure would be more than 0.500 watts.  
(Hmm...  I wonder whether F&P's lab has windows...  :-).  

I would say that the only "dramatic" numbers are those in rows 8 and 9.
Still, the effect of that much extra heat in a perfectly insulated cell
would be to warm it up only 1/5 to 2/5 degree Celsius per minute faster
than its "normal" rate of warming, whatever that is.  (Of course, that
is not what F&P measured.  I understand that their cell is not totally
insulated, so the "excess" heat production manifests itself as a higher
equilibrium temperature, rather then a higher rate of temperature
increase.  Unfortunately the paper does not give a single temperature
measurement.  It also doesn't give the voltages applied to the
electrodes, so I can't compute how much power was actually going into
the cell in each case.  

Note that in experiments 3, 6, and 9 the increase in current density
was obtained by using an electrode only 1/8 as long (or, more likely,
by pulling 7/8 of the electrode out of the water), while keeping the
total current constant.  In that case, I suspect that heating and
bubbling were pretty much confined to the top half inch of the cell.
I find it hard to believe that the cell would still be be adequately
stirred in such circumstances.  

So, since F&P pretty much admitted that their neutron/gamma
measurements were meaningless, their claims seem to be based
essentially on *one* significant published number: the 1.751 watts of
experiment 8, which was computed by them indirectly from measurements
of voltage, temperature, and thermal conductivity that, as far as I
know, are yet to be made public or satisfactorily reproduced.  

While F&P may still be right, I think that skepticism about the reality
of their claims is still quite warranted.  

                Jorge Stolfi
                Department of Cold Confusion
                Division of Experimental Presumption
                DEC Systems Research Center

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       "Truth is tranger than fusion."
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DISCLAIMER: My employer is not in the cold fusion business (yet).