Exception to the Second Law of Thermodynamics, or ...

[David_Simmons]

Hey, you physicists, could there be something to this exception to the second law?

[tomndebb]

I know that I’m missing something, here, but when they fire the laser into the system, are they not adding energy and thereby creating an open, not closed, system?

[David_Simmons]

*Originally posted by tomndebb *
**I know that I’m missing something, here, but when they fire the laser into the system, are they not adding energy and thereby creating an open, not closed, system? **

Yes, but I their experiment supposedly showed them, or at least so they claim, that not all of the added energy is unrecoverable.

The second law also holds, at least at the macroscopic scale, for open systems.

[JS_Princeton]

This is not all that Earth shattering. The Second Law is basically a statistical law. Most of the time you are dealing with such a large number of states that for all intents and purposes it is also a practical law, but at small scales you can have relatively few states and with simple random walks can actually end up violating the second law as there is a larger statistical probability for the unlikely to occur.

No biggee, really.

[Pythagoras]

Well in any case nanotechnology sounds fascinating. Hopefully nannites wont take over my star ship and create a new intelligence though.

[Futile_Gesture]

*Originally posted by JS Princeton *
**No biggee, really. **

Yeah, I thought quantum theory always predicted that on a quantum scale you could “get something from nothing”, just as much as you could lose something to nothing. But on a macro scale it all averages out.

I think this is just confirmation of that.

[David_Simmons]

*Originally posted by JS Princeton *
**This is not all that Earth shattering. The Second Law is basically a statistical law. Most of the time you are dealing with such a large number of states that for all intents and purposes it is also a practical law, but at small scales you can have relatively few states and with simple random walks can actually end up violating the second law as there is a larger statistical probability for the unlikely to occur.

No biggee, really. **

OK, so we either knew, or should have known all along that on the sub-nano scale that randomness rules. That leaves the question of the predictability of the operation of really, really small machines sort of up in the air. Or does it?

[barbitu8]

A recent email I received is, in part, as follows:

The American Institute of Physics Bulletin of Physics News
Number 598 July 17, 2002 by Phillip F. Schewe, Ben Stein, and
James Riordon

PUSHING THE SECOND LAW TO THE LIMIT. Australian
researchers have experimentally shown that microscopic systems
(a nano-machine) may spontaneously become more orderly for
short periods of time - a development that would be tantamount to violating the second law of thermodynamics, if it happened in a
larger system. Don’t worry, nature still rigorously enforces the
venerable second law in macroscopic systems, but engineers will
want to keep limits to the second law in mind when designing
nanoscale machines. The new experiment also potentially has
important ramifications for an understanding of the mechanics of
life on the scale of microbes and cells.
There are numerous ways to summarize the second law of
thermodynamics. One of the simplest is to note that it’s impossible
simply to extract the heat energy from some reservoir and use it to do work. Otherwise, machines could run on the energy in a glass of water, for example, by extracting heat and leaving behind a lump of ice. If this were possible, refrigerators and freezers could create electrical power rather that consuming it. The second law typically concerns collections of many trillions of particles - such as the molecules in an iron rod, or a cup of tea, or a helium balloon - and it works well because it is essentially a statistical statement about the collective behavior of countless particles we could never hope to track individually. In systems of only a few particles, the statistics are grainier, and circumstances may arise that would be highly improbable in large systems. Therefore, the second law of thermodynamics is not generally applied to small collections of particles.

[Phoenix_Dragon]

If they’re using a laser to “trap” one of the beads, it sure doesn’t sound like a closed system…

[JS_Princeton]

*Originally posted by David Simmons *
**

OK, so we either knew, or should have known all along that on the sub-nano scale that randomness rules. That leaves the question of the predictability of the operation of really, really small machines sort of up in the air. Or does it? **

Well, it depends on what you mean by predictability. The way I think it is easiest to explain it is that we live in a quantum world that macroscopically looks classical. The crux of that is the small-scale follows the laws of the large scale whether we actually think those are they way the world works or not.

This principle is what allows for the power of quantum computers. It is why they theoretically will out-preform conventional computing aparati.

[Shalmanese]

I recently posted about whether the 2nd law was absolute in this thread and the conclusion was that, yes, on a microscopic scale, there is a probability that it will be violated, but on a macroscopic level basically never.

There was an article in Scientific American a couple of years back about whether a “Maxwells Demons” type machine was even theroetically possible and it turns out that it is not. I forget what the reason was.

Maxwells demons basically states that imagine you have a microscopic demon holding the gate to a box. If you program the demon so that it opens the box when a fast particle is comng and close the box when a slow particle is coming, you will eventually seperate the hot particles from the cold ones and violate the 2nd law.

[David_Simmons]

*Originally posted by JS Princeton *
**

Well, it depends on what you mean by predictability. The way I think it is easiest to explain it is that we live in a quantum world that macroscopically looks classical. The crux of that is the small-scale follows the laws of the large scale whether we actually think those are they way the world works or not.
**

To put it some kind of way that I can understand, I think. Atoms must either be quantum particles or on the verge be being so. But atoms do combine to form molecules of just two atoms on a pretty orderly basis of the energy required to overcome the electrostatic repulsion of the outer shell, I guess.

[Chronos]

The problem with any sort of Maxwell’s demon is that the demon hass to have some way of distinguishing the different types of particle, and of deciding when to open the gate. Any possible demon which would have such traits would necessarily have entropy of its own which would compensate for the decreased entropy of the rest of the system. Originally, it was thought that the demon required an entropic memory of some sort; the SciAm article showed that it was possible to produce a zero-entropy memory, but entropy then increased in the erasing of that memory to make room for new observations.

[thermodynamics]

Here is an explanation for exceptions to the second law of thermodynamics.
he Amin Cycle is a heat engine cycle. Most heat engine cycles are derived, by

taking into consideration thermodynamic parameters like Temperature, Pressure and

Volume. The effects gravitational force (in other words acceleration force) on the

processes of gases is ignored during the formulation of heat engine cycles in classical

thermodynamics. The Amin Cycle takes into consideration the effects of acceleration

force along with all the parameters of classical thermodynamics. Many interesting results

are observed upon the inclusion of acceleration during the formulation of a heat engine

cycle.

[thermodynamics]

This document has a detailed analysis of the Amin Cycle
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzYW5qYXlhbWluYW1pbmN5Y2xlfGd4OjM3ZTBiNzc0OTE1ZDkwNDg

[Exapno_Mapcase]

Reported for post being a copy and paste job.

[CalMeacham]

@Chronos

The problem with any sort of Maxwell’s demon is that the demon hass to have some way of distinguishing the different types of particle, and of deciding when to open the gate. Any possible demon which would have such traits would necessarily have entropy of its own which would compensate for the decreased entropy of the rest of the system. Originally, it was thought that the demon required an entropic memory of some sort; the SciAm article showed that it was possible to produce a zero-entropy memory, but entropy then increased in the erasing of that memory to make room for new observations.

There were several back-and-forth discussions of such “computer” Maxwell Demnons, and whether informatioon storing violated the conservation laws, and what the limits were, in a set of articles in the American Journal of Physics back in the late 1980s
If you don’t have some kind of “computer” or intelligence, then you need a damping system on your velocity-descriminating trapdoor, as Feynman describes in one of his famous Lectures on Physics. Pretty soon your damping system heats up and doesn’t dampen so well, and your purely mechanical “demon” doesn’t work.