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Author: Jarek DudaJarek Duda Date: Aug 12, 2008 09:21
In microscopic scale chemical reactions are reversible - the dominant
direction depends of parameters (like ATPase H+).
Myosin can change ATP into movement. It's functions are too directed,
too complicated to be reversed in practice.
But imagine simpler molecule which is physically connected to for
example intersections of filaments of cytoskeleton and can catch ADP
and phosphate. Now vibrations would cause movement of the cytoskeleton
which is transferred to the protein, which binds molecules into ATP.
What for? To actively absorb vibration/sound, for example to reduce
turbulations while swimming/flying or ... feed with tectonic
vibrations ...
I'm not saying that it's simple, but looks to be possible.
And if yes, mother nature is extremely inventiveness creature ... look
how sophisticated...
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Author: Jarek DudaJarek Duda Date: Aug 14, 2008 10:22
Feeding with heat can be also indirectly: warm objects emits thermal
infrared - a few micrometers wavelength.
We want to use this energy in much lower temperatures - for example to
power MP3 players:
http://sciencemag.org/cgi/reprint/320/5883/1585.pdf
Photosynthesis for these wavelength could be more difficult than for
visible light, but if it's possible thermophiles should have found
it... (?)
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Author: LorentzLorentz Date: Aug 21, 2008 10:27
On Aug 12, 12:21 pm, Jarek Duda gmail.com> wrote:
rst spot it seems to be against classical thermodynamics -> converting pure heat into different energy. But this theory is strong
> simplification. For example hot iron emits photon. Heat energy is
> random microscopic movement - a noise.
You need a temperature difference.
The hot iron emits photons, but it also absorbs photons. If the
iron is in an equilibrium environment, the two processes are of equal
magnitude. Look up black body radiation. This has been studied plenty
of times.
What you are proposing is a biological thermocouple. Thermocouples
don't work unless one side of the thermocouple is at a different
temperature than the other side. The power output of the thermocouple
is proportional to the temperature difference. This is why
thermocouples really aren't used for power. Their output is too small.
The thermocouple emits and absorbs photons just like your hot iron.
However, the difference in metals plus the difference in temperature
causes a current to flow.
Thermocouples are used in regulators. Air conditioning used to
rely on thermocouples to measure temperature. One side was exposed to ...
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Author: LorentzLorentz Date: Aug 26, 2008 13:04
On Aug 25, 1:47 am, Jarek Duda gmail.com> wrote:> Phenomenological thermodynamics is like Newton's physics - a few
> century old theory ... and is tried to be adjust to experiments
> because physicists have to trust old authorities ... ?
> It is only an approximation! Something like mean field - it assumes
> only simple interactions and usually that particles are independent...
> it forgets that the molecules can organize in some specific
> patterns ... like life :)
> Even forgetting about for example emission of thermal photons, it
> already has problems - for example how You explain that while
> spontaneous crystallization entropy goes into 'forbidden'
> direction...?http://www.garai-research.com/research%%20statement/Entropy/Entropy...
>
> You can argue, but the have working machines which are
> counterexamples :)
> Which can change heat into sound wave and then into electricity and
> then eventually to work!
> Or in given temperatures change naturally produced thermal infrared
> into periodic movement of electrons in wires and than into regular
> movement of electrons... ...
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Author: Jarek DudaJarek Duda Date: Aug 28, 2008 08:59
Ok - imagine empty tube, which internal surface is covered with
perfect mirror. Now near it's one end place two separators -
reflective on the end of the tube and transparent to its middle.
Place hot gas between the separators. It's isolated thermally, but it
produce thermal photons. The only way photon can escape is through the
second end of the tube, so it would work as jet engine - because
photons have momentum in one side, the tube has to get momentum into
the second. And we have stream of photons we can use to create work
somewhere else.
Above example uses that despite that kinetic energy of molecules
behave randomly, each one has specific movement/oscillation, which
energy can be changed into ordered one - electromagnetic oscillation
of photon.
You will say that the problem is with perfect mirrors, but they are
just a perfect isolator for thermodynamics of photons.
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Author: LorentzLorentz Date: Sep 2, 2008 22:47
On Aug 28, 11:59=A0am, Jarek Duda gmail.com> wrote:> Ok - imagine empty tube, which internal surface is covered with
> perfect mirror. Now near it's one end place two separators -
> reflective on the end of the tube and transparent to its middle.
> Place hot gas between the separators. It's isolated thermally, but it
> produce thermal photons. The only way photon can escape is through the
> second end of the tube, so it would work as jet engine - because
> photons have momentum in one side, the tube has to get momentum into
> the second.
True if there are no photons outside the tube. However, an
organism is embedded in an environment that is nearly the same
temperature as itself. So there are as many infrared photons outside
as inside.
In your example, the tube goes nowhere if the energy density
outside the tube has photons with the right density and spectrum to be
at equilibrium with the tube. Because on average every time a photon
leaves the tube, another photon will enter the tube. A photon that
leaves the tube through the silvered part in kicks it left, a photon
entering the tube through the same silvered kicks it right.
Since photons come and go randomly, there is no way to control ...
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Author: Jarek DudaJarek Duda Date: Sep 3, 2008 10:12
I've simplified above counterexample - there shouldn't be any doubts
now.
Everything is in vacuum, without gravity.
Take a tube with interior covered with mirror.
Fix two transparent separators inside and place hot gas between them.
Now place two mirrors on both sides, which can freely move inside the
tube.
Some of thermal infrared photons will be bounced by a mirror - giving
part of own momentum, thanks of momentum conservation law.
The heat of the gas will be slowly converted into momentum of mirrors,
which can be converted into work.
After infinite time all heat energy will be converted into kinetic
energy of mirrors - we will have only gas with T=0 and moving mirrors.
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Author: r normanr norman Date: Sep 4, 2008 22:01
On Wed, 3 Sep 2008 13:12:52 -0400 (EDT), Jarek Duda
gmail.com> wrote:
>I've simplified above counterexample - there shouldn't be any doubts
>now.
>
>Everything is in vacuum, without gravity.
>Take a tube with interior covered with mirror.
>Fix two transparent separators inside and place hot gas between them.
>Now place two mirrors on both sides, which can freely move inside the
>tube.
>
>Some of thermal infrared photons will be bounced by a mirror - giving
>part of own momentum, thanks of momentum conservation law.
>The heat of the gas will be slowly converted into momentum of mirrors,
>which can be converted into work.
>
>After infinite time all heat energy will be converted into kinetic
>energy of mirrors - we will have only gas with T=0 and moving mirrors.
>
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Author: LorentzLorentz Date: Sep 4, 2008 22:01
On Sep 3, 1:12=A0pm, Jarek Duda gmail.com> wrote:> I've simplified above counterexample - there shouldn't be any doubts
> now.
>
> Everything is in vacuum, without gravity.
> Take a tube with interior covered with mirror.
> Fix two transparent separators inside and place hot gas between them.
> Now place two mirrors on both sides, which can freely move inside the
> tube.
>
> Some of thermal infrared photons will be bounced by a mirror - giving
> part of own momentum, thanks of momentum conservation law.
> The heat of the gas will be slowly converted into momentum of mirrors,
> which can be converted into work.
>
> After infinite time all heat energy will be converted into kinetic
> energy of mirrors - we will have only gas with T=3D0 and moving mirrors.
After an infinite time, the mirrors are an infinite distance
apart. Therefore, there is nothing outside the mirrors upon which work
can be done. By your assumption, the only way for the mirrors to do ...
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Author: Jarek DudaJarek Duda Date: Sep 5, 2008 09:14
Perfect mirror is just ideal separator for photons, which should be
allowed for idealized models without energy waste - they don't absorb
heat, only kinetic energy due to momentum conservation.
About argument that there is nothing to use this kinetic energy, there
is no problem to attach a mechanism to mirrors to use it online.
Intuitively 2nd law says that we cannot order energy stored in chaotic
movement, and we've just ordered it into kinetic energy of two large
objects.
About infinite time argument, entropy should change continuously, so
if entropy would be smaller after infinite time, there exists finite
time that it would be already smaller. We alternatively could place
there machinery to use the kinetic energy.
After infinite time everything has T=0 and there is no radiation ...
so entropy is also minimal.
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