The Job of the Demon: Compressing Gas Without Work

In summary, a demon is pushing a cylinder with one wall guard in a way that causes the gas to move left and right. If the demon closes in on the gas while it's moving, he expends energy and the gas moves faster, heats up, and he has to reopen the gas. If he opens the gas while it's moving, he expends energy and the gas moves slower, cools down, and he gains energy.
  • #1
leafy
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TL;DR Summary
I find Maxwell's demon interesting, so I wrote my version of it. Maxwell state it in term of temperature, I wrote it in term of pressure.
Suppose we have a cylinder with one wall guard by a demon. Inside is one gas molecule moving left and right for simplicity.

Now we want to closer the wall (compress the gas) without doing work. The job of the demon is push the wall closer when the gas move left and lock the wall when the gas move right. If he close in the wall while hitting the gas, he would expend energy causing the gas to move faster and heat up.

End of the day the demon has compressed the gas without doing work. If he unlock the wall and let the gas expand, we gain energy. The gas would slow(cool) down and receive energy from the surrounding.

Of course in real life gases is number in moles so it’s impossible to find a chance where all gasses move left, but it’s possible in theory.
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  • #2
How much reading have you been doing about Maxwell's Demon? In that reading, you should have found what the problem is with your setup. How much energy does the Demon expend doing this opening/closing/pushing (accelerate/decelerate) the wall? How much energy is involved in the decision making process of when to move the wall?

https://en.wikipedia.org/wiki/Maxwell's_demon

I must say that there is a common theme to many of your posts. First came Reactionless Drives, then PMMs, now this...
 
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Yes, I'm only interest in something new. I find that the argument against Maxwell's demon is a little short. I also read Feyman's ratchet.
 
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leafy said:
Yes, I'm only interest in something new. I find that the argument against Maxwell's demon is a little short.
But if you keep posting about banned topics or topics that have been addressed here or in the simple literature (like the Wikipedia link that I posted), you are kind of wasting folks' time, no?

Please read the link I posted in detail, and if you have questions, send me a PM. For now (much like your other threads), this thread is closed.
 

FAQ: The Job of the Demon: Compressing Gas Without Work

What is the job of the demon in compressing gas without work?

The job of the demon is to manipulate the particles of the gas in such a way that they move from a lower pressure area to a higher pressure area without expending any energy. This results in the gas being compressed without the need for external work.

How does the demon accomplish this task?

The demon uses its knowledge of the particles' positions and velocities to selectively allow only fast-moving particles to pass through a small opening, while blocking the slower-moving particles. This creates a concentration of fast-moving particles on one side, increasing the pressure and compressing the gas.

Is this process reversible?

Yes, this process is reversible. The demon can also use its knowledge of the particles' positions and velocities to selectively allow only slow-moving particles to pass through the opening, while blocking the fast-moving particles. This results in a decrease in pressure and the gas expanding without the need for external work.

What is the significance of this phenomenon?

The job of the demon in compressing gas without work challenges the second law of thermodynamics, which states that entropy (disorder) in a closed system will always increase. This phenomenon shows that it is possible to decrease entropy and compress gas without the need for external work, which has implications for our understanding of thermodynamics and energy conservation.

Can this phenomenon be applied in real-world applications?

While the phenomenon of compressing gas without work has been observed in experiments, it is not currently feasible to apply it in real-world applications. The process requires precise control over individual particles and is difficult to scale up to larger systems. However, further research and advancements in nanotechnology may lead to potential applications in the future.

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