5 ms·

Thanks for that - great contribution to this discussion, and an independently worthy idea to share. Can you (or anyone) describe in layman's terms the signific

Thanks for that - great contribution to this discussion, and an independently worthy idea to share. Can you (or anyone) describe in layman's terms the significance of 'is x > 0.85?' Looking back to 1993 from today, did the 'critical examination' the author said should happen, ever happen?

nkurz 10y ago
From the link: "The issue is how much deuterium gets into the metal. The ratio of the number of atoms of deuterium in the metal to the number of atoms of palladium is called x. It turns out, by means of electrolysis, or by putting the metal in deuterium gas, that it is rather easy to get x up to the range of about 0.6 or 0.7. That is already a startlingly high figure. If there are almost as many deuterium atoms as palladium atoms in the material, the density of deuterium (a form of hydrogen) is essentially equal to that of liquid hydrogen rocket fuel, which can ordinarily exist only at extreme low temperatures. In other words, palladium (and certain other metals including titanium) soak up almost unbelievable amounts of hydrogen or deuterium if given the chance."
- wallace_f 10y ago
  I don't know if I completely understood that part. So if x = 0.85, scientists can apparently produce cold fusion in a lab?
  - pja 10y ago
    That’s the bit that’s entirely unproven. Something might be happening around that concentration. Or maybe it’s just experimental error (again). But it is interesting that you can cram so much Hydrogen (or Deuterium) into close proximity by absorbing it into a metal & that fact means that these ideas aren’t completely crackpot.
    - skykooler 10y ago
      I wonder whether this could be used to improve hydrogen storage technologies, as a way to store large amounts without needing cryogenic temperatures?
      - Symmetry 10y ago
        At an x of .85 you still have (.15 * 106) / (.15 * 106 + .85) = 95% of the weight in the storage system rather than the hydrogen itself which rules this out for most applications. Even with an x of .99 it's 50/50 when a conventional pressure vessel can get the weight easily below 20%.
        skykooler 10y ago
        It may be heavier, but would it not be more compact? As I understand it, the main difficulty with hydrogen storage is how bulky it is.
      - nkurz 10y ago
        Yes, it's not there yet, but approaches based on metal hydrides are one of the leading contenders for storing hydrogen for electric vehicles powered by fuel cells. Generally, the energy density is better than a battery, but much worse than a hydrocarbon fuel. Here's an overview: https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydrides https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydride...
    - wallace_f 10y ago
      Since the article was written, the author wrote that this was an area for further investigation but no one was doing it because of the politics at the time. Since then, did anyone ever investigate this further?
poelzi 10y ago
it's called the loading factor in this experiment. For 100 pd atoms you need et least 85 D. Best output is ~0.93-.95 and breaks down after wards.

nkurz 10y ago

From the link: "The issue is how much deuterium gets into the metal. The ratio of the number of atoms of deuterium in the metal to the number of atoms of palladium is called x. It turns out, by means of electrolysis, or by putting the metal in deuterium gas, that it is rather easy to get x up to the range of about 0.6 or 0.7. That is already a startlingly high figure. If there are almost as many deuterium atoms as palladium atoms in the material, the density of deuterium (a form of hydrogen) is essentially equal to that of liquid hydrogen rocket fuel, which can ordinarily exist only at extreme low temperatures. In other words, palladium (and certain other metals including titanium) soak up almost unbelievable amounts of hydrogen or deuterium if given the chance."

wallace_f 10y ago
I don't know if I completely understood that part. So if x = 0.85, scientists can apparently produce cold fusion in a lab?
- pja 10y ago
  That’s the bit that’s entirely unproven. Something might be happening around that concentration. Or maybe it’s just experimental error (again). But it is interesting that you can cram so much Hydrogen (or Deuterium) into close proximity by absorbing it into a metal & that fact means that these ideas aren’t completely crackpot.
  - skykooler 10y ago
    I wonder whether this could be used to improve hydrogen storage technologies, as a way to store large amounts without needing cryogenic temperatures?
    - Symmetry 10y ago
      At an x of .85 you still have (.15 * 106) / (.15 * 106 + .85) = 95% of the weight in the storage system rather than the hydrogen itself which rules this out for most applications. Even with an x of .99 it's 50/50 when a conventional pressure vessel can get the weight easily below 20%.
      - skykooler 10y ago
        It may be heavier, but would it not be more compact? As I understand it, the main difficulty with hydrogen storage is how bulky it is.
    - nkurz 10y ago
      Yes, it's not there yet, but approaches based on metal hydrides are one of the leading contenders for storing hydrogen for electric vehicles powered by fuel cells. Generally, the energy density is better than a battery, but much worse than a hydrocarbon fuel. Here's an overview: https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydrides https://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydride...
  - wallace_f 10y ago
    Since the article was written, the author wrote that this was an area for further investigation but no one was doing it because of the politics at the time. Since then, did anyone ever investigate this further?

poelzi 10y ago

it's called the loading factor in this experiment. For 100 pd atoms you need et least 85 D. Best output is ~0.93-.95 and breaks down after wards.