On Jan 31, 2009, at 2:36 PM, Michel Jullian wrote:
2009/1/27 Jed Rothwell <jedrothw...@gmail.com>:
...
This paper is slightly revised:
Celani, F., et al. Deuteron Electromigration in Thin Pd Wires
Coated With
Nano-Particles: Evidence for Ultra-Fast Deuterium Loading and
Anomalous,
Large Thermal Effects. in ICCF-14 International Conference on
Condensed
Matter Nuclear Science. 2008. Washington, DC.
http://lenr-canr.org/acrobat/CelaniFdeuteronel.pdf
I was wondering, could the electromigration pressure possibly induce
deuterium desorption at the negative end of the Pd wire, anyone knows?
Michel
P.S. typo: "braded" should be braided.
I would expect there to be periodiic desorption along the entire
length of the cathode wire because both the electromigration and
loading is driven by 1-2 microsecond pulses, to maximums of 300 V and
150 A, applied at a rate of up to 30 kHz. This implies to me the
concentration in the surface of the *entire cathode wire* increases
for about 1 microsecond of each pulse and decreases for the interim
rest period. I think this is true whether or not the cathode
potential is sustained below some maximum negative voltage, i.e.
sustained as a cathode throughout each cycle.
Celani states the electromigration reaches/creates a [longitudinal]
equilibrium concentration gradient. However, since the loading
current itself drives the entire process, once the loading process
completes by reaching equilibrium I would expect the peak
instantaneous radial electromigration each cycle to far exceed the
peak instantaneous longitudinal migration, both positively and
negatively. Almost the entire 300 V potential is applied radially to
the wire surface, while the longitudinal potential drop through the
wire itself, i.e. the longitudinal i*R drop, is comparatively small,
and the internal longitudinal field strength very small. Also
notable is the fact the vast majority of the longitudinal current
through the wire is via electrons. The net longitudinal
electromigration current is thus very small. I think the hydrogen
component of the electromigration current is essentially a purely AC
current once equilibrium is reached, and that the radial pressure
driven (or concentration driven) component of hydrogen flux far
exceeds the longitudinally driven electromigration component of the
hydrogen flux.
I would think it might be more effective (to isolate and determine
the actual effects of electromigration itself) to drive the
longitudinal electromigration via an A/C process via an A/C potential
applied through the cathode wire directly, while maintaining loading
by sustaining the cathode at a high DC potential. BTW, it has been
known since early on that pulsed DC, i.e. pulsed A/C imposed over the
DC cathodic current was more effective at generating excess heat,
though use of this technique caused a lot of controversy regarding
power measurements.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
