I think the high H loading in the Pd changes the phase of the Pd and
significantly increases the distance between Pd nuclei in addition to the
cracking. The volume change is about 10% I think at 85% loading. The local
internal stresses are also significant.
I think it would be interesting to listen to the electrode with ultrasound to
pick up any acoustic emissions associated with the cracking. The intensity of
the emissions may be related to the reaction rate in the electrode or on its
surface. If so, the location of the reaction--i.e., the fresh cracking which
is associated with activity, could be located with good high temperature
transducers and a program which calculates where the cracking is taking place.
A big electrode would be easier to accomplish UT instrumentation than a small
one.
I wonder if McKubre has tried anything like what I've described?
Bob
----- Original Message -----
From: Axil Axil
To: vortex-l
Sent: Wednesday, May 07, 2014 8:24 PM
Subject: Re: [Vo]:nice essay Jed
High loading produces cracks - NAE
On Wed, May 7, 2014 at 11:18 PM, Jed Rothwell <jedrothw...@gmail.com> wrote:
<mix...@bigpond.com> wrote:
One thing I take issue with (more with standard practice in the CF
community
than with Jed in particular) is the use of the volume of the cathode in
calculating energy density. Since the actual source of energy is likely
to be
the Hydrogen in the water, not the actual cathode metal . . .
Some people say the hydrogen is not very mobile once the reaction starts
up. What you have in the cathode is what there is. The hydrogen at the surface
comes off, but most of the hydrogen in the bulk stays put. Obviously that is
true in heat after death or with gas loading.
Then again, McKubre says flux is important, so who knows.
If Ed is right and the reaction occurs only at the surface, then there
would be rapid exchange with hydrogen in the water. What I do not understand
about that hypothesis is: Why is high loading important, in that case?
- Jed
