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John Cuthber

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Everything posted by John Cuthber

  1. In the particular case of the CuAuAg system, I think the colour would give you a hint. If you measured the reflectance spectrum carefully, it would probably be sufficient. The electrical conductivity might also work, or the hardness, or the speed of sound, or the melting point or magnetic susceptibility or the electrode potential or melting point. But the point remains; you need something to tell you where on that line you are. If you are in the UK and there's a point on the line corresponding to 9 (or 18) carat gold then that's a fair bet, but no proof. But in the USA they seem to prefer 10 carat (as far as I can tell).
  2. So... if I tell you the density of the alloy is 10.5, you can tell me it has a composition which lies on that Isopycnic line. But you can't tell me which composition it is. In other words, you can't tell me anything that Archimedes couldn't have
  3. No, and nor can you. Feel free to post your double blind trial data if you don't agree with me.
  4. Cast iron will crack due to uneven thermal expansion if you are not careful.
  5. No, it's not. If you think I'm wrong, it's up to you to prove it.
  6. The clever bit about those is not the choice of material so much as the big gaps. That means they are less troubled by expansion. They don't buckle and warp because, for the most part, they can just expand a bit. They use cast iron because it's strong enough, has a high enough melting point, and it's cheap. A sheet of cast iron would only be slightly better than a sheet of glass.
  7. Looks like a theoretical solution in search of a problem.
  8. Repeatedly taking away a debt is the same as repeatedly adding a credit.
  9. Copper is less dense than silver. Gold is more dense than silver. Therefore there is a binary alloy of copper and gold which has exactly the same density as silver. We can call it "match" because it has a density that matches that of silver. An alloy of mainly copper with a little gold will be slightly more dense than copper. We can refer to this alloy as "light" and similarly we can have an alloy, which we can call "heavy" made from mainly gold with a little copper. If we start with pure silver we can add a small amount of heavy which will raise the density, and then we can add light to reduce the density. The overall effect will be to produce an alloy which has the same density as silver and which is a ternary alloy. We can repeat that process and get a second alloy- again containing all 3 metals and which has exactly the same density as silver. It will have a different composition from the first one. And we can , add further amounts of light and compensating amounts of heavy until we get arbitrarily close to "match". All these alloys have the same density as silver. How does your method distinguish among them? (The option of extending this to have an alloy with, for example, a density half way between that of gold and silver or whatever also exists)
  10. John Cuthber replied to MSC's topic in Politics
    I think we should tell everyone that. And then the Reps will get complacent and teh Dems will get determined. Anyone remember how the UK's Brexit referendum played out? We all knew that it would fail...
  11. I see the OP thinks misquoting me is helpful. Mind you; he's not entirely wrong. When I asked how he planned to do meaningless magic, I was implicitly pointing out that he was talking kak. But while I will give him the benefit of the doubt and assume his use of "Kak" means "why" (Maybe Russian , Ukrainian Polish or whatever) , my use of it is more like the Dutch.
  12. John Cuthber replied to MSC's topic in Politics
    I don't know who will win. I don't thinks anyone does. But here's a hint about who I would like to win.
  13. There's this https://www.atlasobscura.com/places/wilhelmina-ice-pole-sitting-contest and also everyday life in Scotland.
  14. "Hunting bear and other fur-bearing animals with hounds is a romantic adventure." Stalking is when you go for a romantic walk with someone and only one of you knows about it.
  15. I'm puzzled. What does that mean? They can't afford it?
  16. "Is it possible to generate sulfuric acid from sodium sulfate without special membranes or special processes?" Define "special". Roast the sulphate with charcoal at high temperatures to reduce it to sulphide. Dissolve that in water. Set up some wine or beer making and lead the CO2 that it produces into the sodium sulphide solution. That will form hydrogen sulphide. Oxidise the hydrogen sulphide to sulphur dioxide by burning it in air. Oxidise the sulphur dioxide either with air (as per the contact process) or with ozone, to get sulphur trioxide and allow that to dissolve in water and you will have sulphuric acid. Is any of those steps "special"?
  17. https://en.wikipedia.org/wiki/Ethylene-vinyl_acetate I don't know. The polyurethane foams were notorious for doing that-but slowly. So, the foam would probably last longer than the HDD
  18. You could do that, but you would have to be an idiot. We have coins with his picture on it. So, all you really did there was show that you don't understand the nature of evidence.
  19. By about 17% Probably not going to make a difference.
  20. How often is this useful in a world where you have "always" a phone with you?
  21. Typo. "start" a thread. Not sure that "stat" is a verb.

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