Thanks for the insights all the same. The experiment is indeed confusingly simple (DC current along the wire, in slightly pressurized D2), I too thought initially that there had to be radial currents as well.
I wish the results were confirmed using a more conventional calorimetry though, this one doesn't seem bullet proof to me. Imagine that for some reason the electromigration in Pd yields a D2 flux, this could create a better thermal path from the Pd wire to the Ptmon (temp monitoring Pt wire) than from the Ptcal to the Ptmon, giving the illusion of excess heat. Michel PS To jed: so "braded" exists, I stand corrected 2009/2/1 Horace Heffner <[email protected]>: > Please ignore my post below. I confused the earlier work with the present > experiment. > > Best regards, > > Horace Heffner > http://www.mtaonline.net/~hheffner/ > > > > On Feb 1, 2009, at 6:46 AM, Horace Heffner wrote: > >> >> On Jan 31, 2009, at 2:36 PM, Michel Jullian wrote: >> >>> 2009/1/27 Jed Rothwell <[email protected]>: >>> ... >>>> >>>> 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/ >> >> >> >> > > > > > >
