On Nov 3, 2009, at 2:40 PM, Michel Jullian wrote:
2009/11/3 Horace Heffner <[email protected]>
Yes, those photos are of spots on the back side. However, I
seriously
doubt there are not similar spots on the front side too.
To be sure, one would have to look obviously, but I wouldn't be
surprised if there were no or less hot spots on the front.
So, what is the direction of the deuterium flux through the back
surface
of a Pd cathode close to a plastic window do you think? Out, because
electrolyte paths to get there are more resistive.
I don't think this is right. I think the interface will be about
the
same on both sides. The potential drop through the mesh has little
practical effect.
The mesh is made of wires. The front of the wire will receive more
current than the back, which is close to the plastic window.
If you look at ordinary cathodes in electrolysis, even
big ones, they evolve hydrogen on both sides. Have you ever seen a
cathode evolve gas on only one side?
Sure, they evolve hydrogen on both sides. But if you stick the back
side against an insulator, that side will evolve less, because it will
receive less current, down to zero current at the points of contact.
Now, if the cathode is H/D permeable, the back side will still evolve
gas, but that will be hydrogen which will have gone through the
lattice, like it does in electrochemical hydrogen generators
(electrolytic pressure on one side of a tubular Pd membrane, no
electrolytic pressure on the other side)
This confirms my suggestion, earlier in this thread, that the hot
spots
occur where the deuterium desorbs from Pd deuteride to D2 gas (not
solvated D Horace), which chemically is an endothermic reaction.
These assertions are highly debatable. It appears you are
assuming the
front side looks any different.
I suspect so anyway. One way to know would be to put the anode wire
between the mylar window and the cathode, and look at the cathode
through the anode. Or use Mylar with a thin transparent metallization
as the anode.
An alternative is to put both electrodes in the same plane, as I
suggested here in 2004:
http://www.mtaonline.net/~hheffner/Szpak.pdf
Then there is no front or back. The radial distribution of
electrolyte potential drop can then be used to examine you theory.
The HV electrode cc could be made of any transparent conductor, or
eliminated. It is that electrode that is of most interest to me
though. The edge-on-grid idea is just a variation on this cell
geometry intended to get the electrode back into its original
orientation. Using a mesh cathode accomplishes a similar goal, but
just not with the same precision.
Am I the only one to see how significant this is?
It might be significant if it were true. My point is I don't think
it is true in the sense you are implying it is. I don't think the
interface layers differ much in potential on either side of that
cathode,
and certainly don't think one side is desorbing more than the other.
Except at cracks or any location where there is no electrolyte,
desorption must occur in reverse through the interface, which is
equilibrium with respect to hydrogen flow. The chemical
concentrations
are in equilibrium as well, meaning there is no enthalpy of reaction
because there is no net reaction, except when there have been major
changes in potential such that the Pd loading is in change and
loading or
de-loading is in progress. I expect the electrode filmed is
pretty much
in equilibrium, when it comes to hydrogen concentrations of all
kinds, in
the Pd (i.e. the loading percentage), and in the electrolyte
across the
interface, and in terms of flow rates cross the interface, which
net to
zero. There is thus no enthalpy of reaction involved, especially
on the
front side vs back side.
As you certainly know the loading factor (hydrogen content) depends on
the current density. If you have more current density on one side, you
will have more hydrogen content on that side. And then by diffusion,
you will have migration to the other side and desorption. Implacable,
it's like trying to inflate a punctured tyre.
Michel
If there are spots with similar distributions on the anode side,
which has a slightly higher electrolyte potential than the back side,
and therefore is supposedly in adsorbtion mode, then whatever happens
on the back side is irrelevant. If a theory is denied in any
particular case it is invalidated as a general theory. The theory
that the spots are caused by fusion caused by desorption does not apply.
Beyond all that, the notion that a fraction of a volt is going to
make any difference to a mechanism which can cause fusion makes no
sense. There has to be some additional explanation as to how the kV
order Coulomb barrier is breached.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
