Perpertuum Mobile: The Quest for Perpetual Motion
In terms of the laws of physics, at least as we understand them in the early twenty first century, perpetual motion machines are impossibilities. However, a wide variety of machines, theories and devices have been developed and proposed over the years. Here’s a look at some of the more interesting ones here at Dark Roasted Blend.
http://www.lhup.edu/~dsimanek/museum/unwork.htm
Noether’s theorems couple symmetries to conserved properties. Time is locally homogeneous, mass-energy is locally conserved. There are no loopholes unless you muck with time – no perpetual motion machines of the First Kind.
Entropy of a closed system in a cyclic process over unlimited time prohibits perpetual motion machines of the Second Kind. That seems to have a demonstrable loophole. Take two parallel flat plates closely mounted face-to-face in a hard vacuum envelope. Their supports are wires exiting the vacuum envelope and connected through a very small electric motor. The whole is mounted in adiabatic isolation.
One plate is osmium, large positive vacuum work function. The other plate has its opposing side deposited with tiny diamond pyramids, negative work function into vacuum. The diamond side pepetually emits, spontaneously cooling its plate from electron evaporation. The osmium plate perpetually absorbs, spontaneously warming from electron condensation accelerated through the net work function. IR emission, internal and external, fuels the process by warming the diamond plate. The device spontaneously separates temperatures and powers a motor, never reaching equilibrium. Where is the conceptual error?
You don’t need diamond. Osmium (5.93 eV) versus europium (2.5 eV) vacuum work functions reduces to practice. Clean surfaces! Get fancy with (001)La-terminated surface on LaB6 at 2.07 eV, or fancier by surface substituting Ba in LaB6 to give 1.43 eV for the low end,
J. Phys. Chem. B 110 (37) 18459 (2006)