8 ms·

That's the great thing about thermodynamics, you can determine bounds for a few magnitudes in a physical system ignoring all the details about its evolution. F

by mnl 7y ago

That's the great thing about thermodynamics, you can determine bounds for a few magnitudes in a physical system ignoring all the details about its evolution. For instance you can't disrupt the 2nd law, so at some point it's actually true that it is impossible to mitigate overheating and you won't be able to improve Stefan-Boltzmann law (except for increasing our emissivity, at night I'd guess). You can try to play with mass transfer but more thermal escape is not a good idea and a heat exchanger with extraterrestrial masses won't work. I know it's hard to take and that physicists sound arrogant when they do this, but that's how it is.

cinquemb 7y ago
"Wavelength- and subwavelength-scale particles,[1] metamaterials,[2] and other nanostructures are not subject to ray-optical limits and may be designed to exceed the Stefan–Boltzmann law."
- mnl 7y ago
  Oh well, if you come up with magic materials you can do anything, of course.
  - cinquemb 7y ago
    Its magic when you say embed Au angsrtom scale layering in an Si structure in order to control the wave plane? Any decent E&M research lab can pull out many examples of magic then…
    - mnl 7y ago
      I still don't get why people do this. You can't use snippets of Wikipedia to make a point you don't understand. We're talking about macroscopic systems here. The laws of thermodynamics depend on the law of large numbers (if you take the stat mech route), they can be considered laws about statistical averages. It doesn't matter that somebody in nanowhatever claims a deviation from the macroscopic behaviour, that's their job. You still have a macroscopic Earth. An Earth brimming with grey goo would still obey the laws of thermodynamics.
      - cinquemb 7y ago
        > I still don't get why people do this. You can't use snippets of Wikipedia to make a point you don't understand. I referenced wikipedia and cited an example of such from my experience in physics lab in college nearly a decade ago… I don't get why people try to use some "law" built upon a particular set assumptions that work on a particular set of circumstances expect their leaky abstractions on top of it to govern everything that could ever be possible… >The laws of thermodynamics depend on the law of large numbers (if you take the stat mech route), they can be considered laws about statistical averages. On systems operating under certain assumptions… just like navier-stokes predicting singularities from a specific set of IC's in theory that don't happen in real life from said IC's, which have to be handled with a bunch of corrections and adjustments that are more accurate… we're still working out the math as to why that is…
        mnl 7y ago
        You're mixing up laws with models. Conservation of momentum is a physical law, that is, we're not making that up, we always see it. The Navier-Stokes equation is a continuum mechanics model of fluids with interesting mathematics, but it's not fundamental, it relies on conservation of momentum and additional reasonable assumptions about the fluid, in the same way that for instance the van der Waals equation is reasonable but it's not a law, you find deviations and there are better models. As far as we can tell the laws of thermodynamics are laws indeed, that's why no one is proposing perpetual motion machines of the second kind any more.
        cinquemb 7y ago
        The law I was referring to in this case was Stefan–Boltzmann law (heavily reliant upon assumptions on a given black body that break down under certain circumstances, that people like to hand wave away because they haven't had to deal with the complexities of said circumstances before), which may as well as be a model as far as I'm concerned.
        mnl 7y ago
- BlueTemplar 7y ago
  That's interesting - are they more efficient at getting rid of entropy ? (And what would be the new limits? If they only give, for instance, a single doubling worth, that won't buy us much more time...)
  - cinquemb 7y ago
    This was my prof at the time who introduced me to this stuff he was working on[0], you can read more about his work on their site if you are interested. [0] http://www.zia-lab.com/ http://www.zia-lab.com/

by mnl 7y ago

cinquemb 7y ago

"Wavelength- and subwavelength-scale particles,[1] metamaterials,[2] and other nanostructures are not subject to ray-optical limits and may be designed to exceed the Stefan–Boltzmann law."

mnl 7y ago
Oh well, if you come up with magic materials you can do anything, of course.
- cinquemb 7y ago
  Its magic when you say embed Au angsrtom scale layering in an Si structure in order to control the wave plane? Any decent E&M research lab can pull out many examples of magic then…
  - mnl 7y ago
    I still don't get why people do this. You can't use snippets of Wikipedia to make a point you don't understand. We're talking about macroscopic systems here. The laws of thermodynamics depend on the law of large numbers (if you take the stat mech route), they can be considered laws about statistical averages. It doesn't matter that somebody in nanowhatever claims a deviation from the macroscopic behaviour, that's their job. You still have a macroscopic Earth. An Earth brimming with grey goo would still obey the laws of thermodynamics.
    - cinquemb 7y ago
      > I still don't get why people do this. You can't use snippets of Wikipedia to make a point you don't understand. I referenced wikipedia and cited an example of such from my experience in physics lab in college nearly a decade ago… I don't get why people try to use some "law" built upon a particular set assumptions that work on a particular set of circumstances expect their leaky abstractions on top of it to govern everything that could ever be possible… >The laws of thermodynamics depend on the law of large numbers (if you take the stat mech route), they can be considered laws about statistical averages. On systems operating under certain assumptions… just like navier-stokes predicting singularities from a specific set of IC's in theory that don't happen in real life from said IC's, which have to be handled with a bunch of corrections and adjustments that are more accurate… we're still working out the math as to why that is…
      - mnl 7y ago
        You're mixing up laws with models. Conservation of momentum is a physical law, that is, we're not making that up, we always see it. The Navier-Stokes equation is a continuum mechanics model of fluids with interesting mathematics, but it's not fundamental, it relies on conservation of momentum and additional reasonable assumptions about the fluid, in the same way that for instance the van der Waals equation is reasonable but it's not a law, you find deviations and there are better models. As far as we can tell the laws of thermodynamics are laws indeed, that's why no one is proposing perpetual motion machines of the second kind any more.
        cinquemb 7y ago
        The law I was referring to in this case was Stefan–Boltzmann law (heavily reliant upon assumptions on a given black body that break down under certain circumstances, that people like to hand wave away because they haven't had to deal with the complexities of said circumstances before), which may as well as be a model as far as I'm concerned.
        mnl 7y ago
BlueTemplar 7y ago
That's interesting - are they more efficient at getting rid of entropy ? (And what would be the new limits? If they only give, for instance, a single doubling worth, that won't buy us much more time...)
- cinquemb 7y ago
  This was my prof at the time who introduced me to this stuff he was working on[0], you can read more about his work on their site if you are interested. [0] http://www.zia-lab.com/ http://www.zia-lab.com/