🚀 go-pugleaf

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About JoSH's objection: Certainly the "rubbery" nature of the cylinder
I was proposing causes problems, but how would you prove that they
make the device impossible?  I might try and argue that the kinetic
energy is not be equal, just the thermal energy, and that the somewhat
greater stiffness of the cylinder might let you see the motion of the
gas molecule as a very small "signal" on top of the thermal "noise" of
the cylinder.

Another way to look: can you build a piezoelectric crystal so small
that it's thermal fluctuations can be detected as a voltage across the
crystal?  I would guess that if you could, you'd have a 2nd law
violation, hence I expect you can't, but why not?

In general about these comments: It seems to me that the nature of
this game is that you can't just say "this contradicts the second law,
therfore it's impossible".  The idea is to find an inherent design
flaw working from the ground up, and hence verify the second law.  I
would be suprized (to say the least) if I get anything out of this
than a somewhat improved understanding of thermo...  

So, I'll re-read Drexler on the Maxwell's nano-Demon disproof, and I'll
even try flipping though some recent SA's to see if I can trace Henry
Cobb's reference.  Thanks for the comments. 

-- Joe B.

[I don't know that anything about nano-Demons is in EoC--I couldn't
 find anything in a quick review.  Look at Cellular Automata Machines
 by Toffoli and Margolus (and papers by either, and by Fredkin) and
 the oft-mentioned Emperor's New Mind by Penrose for a nice overview
 of entropy matters (skip the AI part).

 I would imagine you get some voltage variation in any material directly
 due to the electronic component of the thermal energy, it doesn't 
 have to be piezo-electric.  The same arguments would apply to it as
 to mechanical motion--you'll have as hard a time building a diode
 for nano-voltages as a ratchet for nano-motions.

 There is no proof in my original reply--it was just explanatory.
 The proof, if you need one, would have to be built up from the 
 reversibility of physics at the micro-level.

 --JoSH]