At 03:55 PM 9/23/2012, Jed Rothwell wrote:
David Roberson <<mailto:[email protected]>[email protected]> wrote:
Do you recall an event mentioned by F&P where the device burned it
way through a table or floor?
That as the "cube" I referred to. I listed it in my book. There are
no photos or other physical evidence, I am sorry to say. As far as I
know, electrolysis was running when this occurred.
Maybe. We may not have any way to find out, though Pons' son Joey
might know better than anyone. Beaudette, "Excess Heat, Why Cold
Fusion Prevailed," writes (2nd edition, 2002, p. 36):
By the late fall of 19843, the experiment had been running
continuously for several months. At one point, Pons raised the
current from its nominal rate of 0.75 amperes to 1.5 amperes, and
that the end of the day, sent Joey to turn off the current. They
left the laboratory for the night.
Joey came in the next morning and found the experiment in a shambles.
In the Preliminary Note (1989), P&F&H wrote:
We have to report here that under the conditions of the last
experiment, even using
D2O alone, a substantial portion of the cathode fused (melting point
1554 deg. C), part of
it vapourised, and the cell and contents and a part of the fume
cupboard housing the
experiment were destroyed.
Beaudette addes a report from Kevin Ashley, a graduate student of
Pons at the time, stating that,
"The bench was one of those black top benches that was made of very,
very hard material. There were cabinets under on end of the bench,
but the experiment was near the middle where there was nothing
underneath. I was asonished that there was a hole through the thing.
The hole was about a foot in diameter. Under the hole was a pretty
good pit in the concrete floor. It may have been as much as four inches deep.
"What really surprised me," Ashley continued, "was that Stan and
Martin Fleischmann had those looks on their face as though they were
the cat that had just swallowed the canary. They were happy about
what had happened. I was rather surprised by this, very surprised by this."
A centimeter cube of palladium, heavily loaded with deuterium. That's
a lot of deuterium, but ... it's difficult to imagine a chemical
accident that would generate the heat necessary to do what was
described. One can determine the heat available from assuming very
high loading, say, 95%, it was quite likely less than that. This heat
would not be immediately available, though. If we imagine that the
cube started degassing with power off, there wouldn't be a reason to
expect ignition. The release of deuterium from palladium is
endothermic. The gas would simply be generated and would escape.
There is only a little oxygen in the cell, but it would be an
explosive mixture at this point. The fumes was still dust in the air,
Ashley reports, in the morning, so the explosion probably didn't
happen immediately. As the palladium deloaded, it would cool and also
flush the oxygen out of the cell.
If it were ignited, the flame would heat the palladium, increasing
degassing, but the flame would be limited by the available oxygen,
and it would rather quickly be quenched, I'd expect, by the water
vapor. Only if the cell were breached by an explosion would more
oxygen be available, and I'd expect flame, not an explosion. Only
right at the beginning of this process would there be an explosive
mixture, but later, ignition would not be possible, I'd think. No
source of oxygen in the cell.
Now that we know that PdD can sometimes trigger D fusion, regardless
of what the mechanism is, and we also know about Heat After Death as
a commonly reported phenomenon -- i.e., a heat burst, which can last
a long time, after the electrolytic current is turned off -- the
meltdown isn't so mysterious. They got one whopper of a heat burst.
They -- and nearly everyone after them -- scaled down, because they
might have been lucky. What if that heat burst was at the low end of
possibility rather than the high end, as we tend to assume, given how
difficult it's often been to set up the Fleischmann-Pons Heat Effect?
Palladium is 12 g/cm^3. Its atomic weight is 106.42. So the number of
moles of Pd is 12/106.42, or 0.113. For simplicity, let's assume a
tad under 1:1 loading, so we have about a tenth of a mole of
deuterium. The enthalpy of combustion for hydrogen (close to that of
deuterium) is 286 kJoules per mole. So there is about 29 kJ available
from combustion. To raise a tenth of a mole of palladium about 1500
degrees to the melting point will take, from the molar heat capacity
of 25.98 J/(mole*deg K), about 3.9 kJ, and another 1.7 kJ to actually melt it.
So there is enough energy available; however, the problem would be
releasing this energy so rapidly and with such efficiency of transfer
to the palladium, that the palladium would be heated to melting. The
image here would be of a flaming piece of palladium. There could be
no oxygen inside the palladium, rather as the palladium is heated by
burning deuterium at the surface, it would release more and more
deuterium, moving the flame front away from the palladium and
reducing heat transfer. Something would need to first ignite the
deuterium and allow oxygen to reach it; the oxygen in the cell would
be trivial, and would be quickly blown out before much deuterium
burned, even if there were ignition (unless ignition happens
immediately, when the cell mixture is still explosive).
Something would need to cause a rapid heat rise, adequate to destroy
the glass cell. HAD is the likely candidate. There is no ignition
source in the cell, other than that. Once the cell was broken, then
oxygen would reach the palladium and, being hot enough, the deuterium
being released would burn. But with a flame, not as an oxy-hydrogen
torch. It's still difficult to imagine how the hole was burned into
the concrete floor.
Heat rise sufficient to melt the palladium will almost certainly
extinguish any cold fusion, which requires the structures of the solid state.
So I imagine this sequence:
HAD raises the temperature of the palladium, after boiling off the
electrolyte (which expels oxygen, by the way), to the point that the
cathode supports melt, and then the hot palladium, in contact with
the glass, melts the glass. At this point oxygen from the air can
reach the palladium, which ignites the deuterium being released.
Heat from this increases the release of deuterium. The nuclear
reaction continues, increased by the heat, increasing the temperature
of the palladium toward melting; the flame alone would not cause it
to reach melting. As the palladium melts, the nuclear reaction,
losing its catalytic environment, shuts down. I'd expect the balance
of the deuterium to be very rapidly released as the palladium melts,
so there would be a lot of flame. But flames put most of their heat
into the air, not back into the fuel source. Consider a candle
wick.... the flame never touches it, until the flame has gotten low
enough that the top of the wick is actually engulfed in flame. The
whole piece of palladium would be rapidly evolving deuterium, which
would be cooling it, to a degree, and which would insulate the
palladium from the direct heat of the flame.
Frankly, I hate doing math when I'm not intimately familiar with the
calculations. So someone check my procedure and math, okay?
Anyway, I still have difficulty imagining how the hole could be
burned in the floor. Lab bench, okay. Concrete floor?
