At 12:03 PM 9/3/2012, Jeff Berkowitz wrote:
I don't know how Kim at Purdue is regarded in
this group, but aside from his theoretical work,
his ICCF-17 paper proposes three experiments
along these lines. They are: (a) Determine the
velocity distribution of deuterons in metals,
which he states "is expected to be different"
from an ideal gas. (b) Additional measurements
of the diffusion rates in metals. (c) Put metal
nanoparticles in 4He and see what happens.
<http://lenr-canr.org/acrobat/KimYEconvention.pdf>http://lenr-canr.org/acrobat/KimYEconvention.pdf
Conventional Nuclear Theory of Low-Energy
Nuclear Reactions in Metals: Alternative
Approach to Clean Fusion Energy Generation
Oh, I so much wish that scientists in this field
would stop jumping way, way ahead, to give
implications way behind what they are actually able to write about.
We know that
1. If LENR is real, and
2. If it can be made practical,
then
Yes, there are huge implications for our energy future.
It took many years of research to establish the
first proposition, and that work did not
establish the second. That fact is often cited by
pseudoskeptics as some kind of proof against the
first proposition, but that's preposterous. An
effect can easily be real but not be practically
accessible, such as the Fleischmann-Pons Heat
Effect, which is famously unreliable, requires
expensive materials, and it looks like the
reaction ultimately destroys the reaction sites, in rather short order.
And we don't have confirmed science yet on the
alternative approaches, such as NiH. We don't
even know the ash from NiH, not to mention have a
clear and widely-confirmed handle on heat from it.
Cryogenic ignition of deuteron fusion in metal
particles is proposed as an alternative
approach to clean fusion energy generation.
B. D+D Reaction Channels in Metals
From many experimental measurements by
Fleischmann and Pons [16] in 1989, and many
others [17-19] over 23 years since then, the
following experimental observations have
emerged from experimental results reported from
electrolysis and gas-loading experiments. They
are summarized below (as of 2011, not complete:
exit reaction channels {4}, {5}, and {6} are
defined below and are shown in Fig.1):
(1) The Coulomb barrier between two deuterons are suppressed.
(2) Production of nuclear ashes with anomalous rates:
R{4} << R{6} and R{5} << R{6}.
(3) 4He production commensurate with excess heat
production, no 23.8 MeV .-ray.
(4) Excess heat production (the amount of excess
heat indicates its nuclear origin).
(5) More tritium is produced than neutron R{4} > R{5}.
(6) Production of hot spots and micro-scale craters on metal surface.
(7) Detection of radiations.
(8) Heat-after-death.
(9) Requirement of deuteron mobility (D/Pd > ~0.9,
electric current, pressure gradient, etc.).
(10) Requirement of deuterium purity (H/D << 1).
[...] [list of reactions for item 2]
{4} D(m) + D(m) . p(m) + T(m) + 4.03 MeV (m);
{5} D(m) + D(m) . n(m) + 3He(m) + 3.27 MeV (m);
{6} D(m) + D(m) . 4He(m) + 23.8 MeV (m),
where m represents a host metal lattice or metal particle.
Aw, this drives me nuts. Good thing I was already
nuts, or this would be a serious problem....
Kim is unfortunately confusing conclusions,
largely premature, from experimental observation
with the observations themselves. Some of what he
states is closely rooted in observation, some is
reasonable conclusion from it, some is
speculation. All mixed together. Let's look:
1. That's not an experimental observation,
period. It would be very difficult to observe, at
best. It's a conclusion from the fact of LENR,
but not all forms of LENR necessarily involve a
"suppression" of the "Coulomb barrier."
2. The ashes are confused with a set of reactions
that would produce them. The ashes may be
produced -- and almost certainly are produced --
by other reactions. R4 and R5 are certainly not
happening, but the evidence that R6 is happening
is weak, because of the missing gammas. While
someone, including Kim, might yet pull a rabbit
out of the hat, it looks, at first sight, that R6
is not happening either. There are other LENRs
that can produce helium, the most notable being 4D -> Be-8 -> 2 He-4.
3. Correct.
4. Correct.
5. Correct.
6. Correct, apparently.
7. Radiation is only detected at low levels, and confirmation is weak.
8. Correct.
9. Correct. But electric current is not required.
This is merely some kind of misstatement.
10. Correct for PdD, apparently. About 1% H, atom
percent, is adequate to poison the effect.
Number 10 actually shows that he's only talking
about the FPHE, and thus *not* about reasonable
"clean fusion energy generation."
That's fine, in itself, I'm only complaining
about connecting energy generation with what
should primarily be, as it should have been in
1989, pure science. That linkage, then, weakens
the presentation, as obvious counterarguments become legitimate.
Now, to the rest of the paper.
Velocity distributions of protons (dueterons) in
metal have not been measured as a function of temperatures.
This is important. Takahashi and Kim both propose
the formation of condensates, Kim proposes
explicit Bose-Einstein Condensates, it turns out,
from extensive discussion with Takahashi, that he
is proposing a different kind of condensate (but
related), that does not reach or require the
ground state. I still lump them together as BEC theory.
Takahashi proposes, to be clear, a family of
reactions, but he's only calculated one or a few.
He's calculated the fusion cross-section for four
deterons, being two deuterium molecules, with the
deuterons in an initial tetrahedral configuration
(and including the electrons). This, he finds
from calculations using quantum field theory,
will collapse in about a femotosecond and fuse
within another, 100%. Kim does not seem to attempt any similar calculation.
Kim is proposing that a BEC forms with all the
deuterons bound in a single metal particle. He is
suggesting that this may be enhanced by cooling
the material. So as to the cratering,
For the micro-crator shown in Fig. 2, we have
the ejecta volume of V = 1.6x10-8 cm3 which
contains 1.1x1018 deuterons, corresponding to
Nmoles=1.8x10-9 moles of deuterons. The total
energy ET required for vaporization is ET =
6.5x10-4 joules. Since Q=23.8MeV per nuclear
reaction, the total number NR of D+D reactions
is NR = ET/Q = 1.7x108 DD reactions. Explosion
time estimated from Eq. (12) is ~1.2x10-13 seconds/ Ù.
Remember, these explosions are in materials at
room temperature. So this would require about
3.4 x 10^8 deuterons to be in a relative ground
state. This seems preposterously unlikely.
Takahashi's condensate requires four, and even
then people reject it because of the high temperature (which may be an error).
The known FPHE increases rate with temperature,
which is the opposite of what would be expected
from local cooling. The Takahashi reaction (4D
TSC) requires reaching a particular physical
configuration, requiring energy, which is
presumed to be available thermally. (And,
remember, we don't know the temperature distribution of deuterons in Pd).
Kim proposes some experiments.
1. To determine the velocity distribution of
deuterons in Pd, using the Inelastic Compton
scatterings of neutrons and of X-rays. Great idea.
2. To explore the superfluidity of the BEC of
deuterons in metal. While the investigation would
be valuable, it's likely that BEC formation in PD
is at quite a low rate,if it exists at all. This
kind of detection of BECs could be extraordinarily difficult.
3. To explore ignition (mini-explosions) at
extremely low temperatures. If this hasn't been
done, it should be. Notice that if Kim is
correct, this would be an extremely dangerous
experiment; however, the temperature would
gradually be approached, and evolving heat would
defeat the cooling. That would likely be the
effect actually observed. Rapidly cooling a large
volume, fast enough to outrun the heat, would be extraordinarily difficult.
Kim proposes number 3 as leading to an approach
for commercial power generation. That seems quite
unlikely, even if it works. Cooling to the
temperatures required is energy-intensive.
However, that is a question for future
generations. My interest is in the science. Kim
has added a little light to a field, but not as
much as I'd hope for. The bulk BEC, as such,
seems quite unlikely, and how it would fuse isn't
really stated, Kim does not appear to have done the math.
Kim suggests that cooling will increase the
reaction rate, which might be true for his
proposed mechanism, but, then, this strongly
implies that the actual reaction seen in the FPHE
is not Kim's mechanism, since that reaction rate increases with temperature.
Kim is reputable, to answer the original
question, his paper was published in
Naturwissenschaften recently. I see him as
proposing a line of approach rather than a mature
theory that could explain most of the known
phenomena. His explanation that the energy is
dissipated among all the constituents of the BEC,
including metal atoms, is a fairly obvious one,
but does not address the exact nature of the BEC.
The formation of large BECs, as he clearly
proposes, seems preposterously unlikely, given
that the probability of finding all those
particles at very low relative momentum, given an
energy distribution, would decrease rapidly with
the number of particles. I don't see that he has
addressed this problem at all, even though this is the most obvious objection.
Something I've long noticed: Kim and Takahashi do
not cite each other. Ever. Yet they are obviously
covering somewhat similar ground.
The bottom line: we do not have enough
experimental data to distinguish between the
plausible competing theories. Every one of them
starts with assumptions that appear to violate or
differ from what is known. Before investing much
into a theory, I'd suggest, the necessary
assumptions should be validated in some
independent way. Determining the velocity
distribution of deuterons in Pd would be a start, and that could be doable.
