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I'm a post-doctoral researcher with a wide range of interests. My career is in complex systems science (or maybe cybernetics) and the origins of life, but I also have research interests in

  • the foundations of statistical mechanics and its relationship to information theory
  • Earth systems science
  • non-equilibrium thermodynamics in general

I'm also generally interested in the foundations of quantum mechanics and in black holes, though I wouldn't say I'm an expert on those things.

It's probably worth noting that despite the fact that my research is in physics-related areas, all my degrees are in other subjects. If I occasionally seem to start talking in an alien language, this is probably why.


Sep
30
awarded  Yearling
Sep
29
awarded  Informed
Sep
28
comment Disequilibrium during infinitesimal steps of a thermodynamic reversible process & cause of maximum work to be achieved during reversible process?
... If there is no friction at all, the oscillations will take place for a very long time - but not forever, because the gas itself has some viscosity, and this will eventually turn the kinetic energy into heat. On the other hand if there's lots of friction the piston won't oscillate at all, but will just slowly move towards its equilibrium point. But in all of these cases the amount of heat generated will be the same. It has to be, because the final position of the piston is the same, so the energy difference between the initial and final states is the same. All that energy must become heat.
Sep
28
comment Disequilibrium during infinitesimal steps of a thermodynamic reversible process & cause of maximum work to be achieved during reversible process?
@user36790 actually it's due to a lack of friction. Imagine the system before you remove the first piece of lead. The pressure force balances the weight of all the lead shot. Now remove one piece - now the pressure is the same, but the weight is less, so the piston will start to move up. But this decreases the volume, and therefore the pressure force. Shortly the weight will be greater than the pressure force, so the piston will slow down and reverse its direction, compressing the gas again. These oscillations will continue until friction damps them, and this friction generates heat. ...
Sep
27
comment Is a chain REALLY only as strong as its weakest link
I've edited my answer - see the last paragraph.
Sep
27
revised Is a chain REALLY only as strong as its weakest link
added 723 characters in body
Sep
27
comment Is a chain REALLY only as strong as its weakest link
This isn't really a case of the thicker string being weaker, though, it's just a case of more force being applied to the stronger string than the weaker one.
Sep
27
comment Disequilibrium during infinitesimal steps of a thermodynamic reversible process & cause of maximum work to be achieved during reversible process?
...this means that the total energy change of the system is the same - the question then is how much of that energy went into heat, and how much went into work? In the case of the lead shot, most of it goes into work - when you remove a piece of shot, the piston lifts the rest of it against gravity, which is work. But it also jiggles the piston around a bit and makes some heat. When you remove a grain of sand, the amount of jiggling is much less and so even more of the energy goes into work. By the time you get to infinitesimal grains, there's no jiggling (and no heat generated) at all.
Sep
27
comment Disequilibrium during infinitesimal steps of a thermodynamic reversible process & cause of maximum work to be achieved during reversible process?
@user36790 after you've removed the 1000 pieces of lead shot, you've removed a total weight of $1000mg$. This has allowed the piston to expand, doing work. After you've removed the 100,000 grains of sand, you've removed a force of $100{,}000\times (m/100)\times g = 1000mg$, the same as for the lead shot. So although the total amount of heat generated by friction goes to zero as the size of the grains decreases, the total change in volume and force stay the same. (to be continued...)
Sep
27
answered Is a chain REALLY only as strong as its weakest link
Sep
26
answered Disequilibrium during infinitesimal steps of a thermodynamic reversible process & cause of maximum work to be achieved during reversible process?
Sep
25
comment Why is the sky never green? It can be blue or orange, and green is in between!
There are definitely some green pixels in that image, but I think if you're actually looking at the sky it's very difficult to perceive it as green, rather than a sort of superposition of orange and blue. I'll have to pay attention to it next time I see a sunset like that.
Sep
25
revised When the low temperture reservoir with negative temperture (Kelvin), such as Ising model, is the efficiency of ideal heat engine larger than 1?
deleted 2 characters in body
Sep
25
answered When the low temperture reservoir with negative temperture (Kelvin), such as Ising model, is the efficiency of ideal heat engine larger than 1?
Sep
24
awarded  Autobiographer
Sep
22
revised Why the self-information is -log(p(m))?
edited body
Sep
22
answered Why the self-information is -log(p(m))?
Sep
18
comment Thermodynamics: heat transfer
No time to write a detailed answer, but in short you're 100% correct, energy flows in both directions, always. The second law applies to the net transfer of hot-to-cold minus cold-to-hot, averaged over time.
Sep
18
answered Is speed an intensive property?
Sep
16
awarded  Necromancer