Jump to content

exchemist

Senior Members
  • Posts

    3474
  • Joined

  • Last visited

  • Days Won

    52

Everything posted by exchemist

  1. Yup, so 2/10 of F-all . You think you can run a viable fusion reactor on that basis?
  2. If you consult the table in the link I provided, you will see >99.99% decay into 2 x 1H, i.e. the 2 protons just fly apart. But it doesn't.
  3. No. The half life is apparently << nanosecond: https://en.wikipedia.org/wiki/Isotopes_of_helium According to my understanding there is no Coulomb “barrier” anyway, in the sense of the repulsion diminishing at very short distances. The repulsion goes on up without limit, so far as I know. Nuclear stability relies on the strong interaction outweighing it, which for 2He it apparently doesn’t.
  4. No. A pair of protons with no neutrons would be unstable and fly apart - and you need neutrons in your fusion reaction anyway, to make helium, which is the product of the reaction. Fusion is usually between deuterium and tritium, leading to helium + a neutron that carries away most of the liberated energy. Deuterium is sourced naturally from water while tritium is "bred" by letting the escaping neutrons react with lithium in a "breeding blanket" surrounding the reaction chamber.
  5. I think there is something wrong here. My understanding is that the entropy corresponds to the information needed to fully describe the system that is absent. Or actually a better word might be unavailable. So you can't equate entropy with information, but to its unavailability. There is a discussion of this here: https://physics.stackexchange.com/questions/75146/entropy-and-information
  6. Is the journal reputable or is it one of those potentially predatory ones that appear on Beall’s List, for example? You can I think share the name of it if you like. I can’t see why doing so would be a problem.
  7. Are you suggesting such people experience a lower air pressure? If not, what relevance does this have to your hypothesis?
  8. Irrelevant to the thread question.
  9. Wind direction is specified according to the direction it comes from, as that is what you feel on your face and how you relate to the wind to set your sails and steer your vessel. I couldn't quickly find a reference to a "northern current", but I imagine it might make sense to refer to that according to the direction in which it causes your vessel to drift.
  10. That's what I had in mind. But let's see if someone jumps in and tells me I'm quite wrong.........
  11. I’m rusty on this but I should have thought you can get work out of a process with -ve change in G. For instance you could have an electrode potential in a suitable electrochemical cell, even if you could not run a heat engine. If you did find a way to extract work, I think the enthalpy change would become even more -ve, to balance the books. But I’m very much open to correction on this.
  12. Fair point. It all seems to be very murky.
  13. I had read he was a merchant trading goods through to the Mediterranean. Seems likely to me he did quite a lot of travelling. But it is all very obscure, certainly.
  14. Not much passed through Mecca though. More likely Mohammed brought ideas back from his travels to the North. (I admit to being attracted to the “revisionist” school of Wansbrough et al, as it seems to me relatively objective and historical, whereas so much of what is presented as the history of Islam is suffused with the tradition of believers, which cannot often be corroborated.)https://en.wikipedia.org/wiki/John_Wansbrough
  15. Yes I know but the religion did not spring, fully formed, from Mohammed.
  16. I think it arose in the c.5th, probably in Mesopotamia, out of the mix of Judaism, Christianity and other influences. I came into contact with it when I lived in the Middle East. It can engender a very attractive, calm and gentle attitude in its adherents (men and women). But of course in its strident militant form it is just as bad as the Puritanism of old in the Christian world, or even worse. So as with most religion, it can have both positive and negative aspects.
  17. Well no, in general valence band electrons can't tunnel. The barriers are too high and too thick. You would need very special circumstances for tunnelling to be possible, I think.
  18. Well then, if they are localised in the valence band they won't participate in superconducting behaviour, will they? I'm not a solid state physicist but my understanding is conduction requires a continuum of delocalised states, so that there is no energy gap to be jumped when an electron is given a bit of extra energy.
  19. But if they fall into a localised state (presumably of lower energy if they "fall" into it) they cease to be conduction electrons, surely? In effect they go into the valence band, don't they?
  20. For these to be “conduction electrons”, wouldn’t the state have to extend throughout the crystal? But would they then be treated as paired?
  21. There is an article in today's Financial Times, saying that the European space industry is also going down the route of commercial competition. So yes, this is a natural progression, once a technology has been sufficiently mastered and once commercial exploitation opportunities open up in the field in question. It was not so long ago that nuclear power was all in state hands. But now, it no longer is. But the private sector needs a return on investment that justifies the level of risk in the enterprise. Where there is little or no commercial return, and/or the risks are high, private enterprise will not get involved. Private enterprise may also be denied access to a sector if there is no prospect of effective competition (anti-monopoly legislation). So these are the areas where governments have to step in. I am honestly not sure I understand what point you want to make, apart from having some kind of animus against NASA.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.