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John Cuthber

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Everything posted by John Cuthber

  1. The blue colour you sometimes see with copper is due to CuCl- it's not clear where the chloride is from. Traces of PVC insulation from the wire might explain why you think copper usually gives a blue flame. Traces of sodium will turn the flame yellow and that will mix with the blue. So any colours of blue, green and yellow are possible.
  2. Plenty of things give hydrogen without catching fire, so the interesting question is what ignites it?
  3. Not all cold packs use ammonium nitrate, some use urea (Other's might be possible too) If you try to light the mixture with a match, what happens?
  4. OK, if you replaced the sucrose with fructose or glucose what would be the major causes of caries and obesity? Also, how do you plan to ban something so common? Do you plan to cut down the apple tree in my garden?
  5. It's a bit awkward with sugar derivatives like ribose to work out where to start counting; especially when they have two conformations. I'd find the IUPAC name, check it carefully, and use it.
  6. On what basis do you say that? How does the body know that the sucrose has been removed from a plant and added to some food, rather than it's just naturally part of that food? Is the plan to upset people who grow things like rhubarb and gooseberries which are not very sweet and so most people won't eat them without added sugar?
  7. Good luck with herding cats. Make a point early on in the thesis of citing the IUPAC names and the INN where it exists then use an abbreviation that makes sense to you. That way you will (probably) be consistent. Anyone who knows the field well enough to "judge" your thesis will be aware of the variations available. As long as you are consistent they can't complain much. If you happen to know who will be looking at your work, find a paper they wrote, and use the same abreviations they use.
  8. Well, according to WIKI fludeoxyglucose (18F) is 2-deoxy-2-(18F)fluoro-D-glucose and I agree with them. I think 3'-Deoxy-3'-[18F]fluorothymidine is correct chemically. What are you actually looking for here?
  9. Do you have any idea how widespread sucrose is? Banning it would ban many fruit like apples and bananas. Also, if you somehow replaced all the sucrose by glucose or fructose then the major cause of dental caries and obesity would be glucose or fructose.
  10. How hard did you look https://news.yale.edu/2016/05/23/outstanding-students-honored-class-day-2016
  11. Transfer of momentum to and from photons is well documented. https://en.wikipedia.org/wiki/Compton_scattering
  12. Whatever the photon "bounces" off is set moving.
  13. If I bounce a single photon off a ( well made, blazed) diffraction grating where is it likely to go? Sometimes , it's clearly not the same photon, because it has changed colour. https://en.wikipedia.org/wiki/Raman_scattering
  14. You need to distinguish "man bites dog" from "dog bites man" and "man is bitten by dog".
  15. Between media it changes direction- that's refraction. in any given medium it doesn't usually change direction- because of the conservation of momentum. But sometimes the photons do change direction- and occasionally their energy. That's scattering.
  16. This is one of those cases where a picture is worth more than a thousand words, even if it's a shoddy sketch done in paint.
  17. It's a matter of degree, rather than absolute.
  18. It's as if there's a second clause that distinguishes those who "abuse the process for their gain".
  19. We call ourselves Great- what does that say about us? Rangers or Celtic? It's certainly better than many, but it's not what it should be. The current govt is trying very hard to make it worse- Brexit is a case in point.
  20. Really? Are you sure?
  21. To whom do they appear that way?
  22. Yes. Incidentally, if you put someone like this in charge,- someone who has no idea what the issues are- how can you say you ? https://www.facebook.com/theguardian/videos/10156163592166323/
  23. It's right- NASA are good at that sort of thing. What is remarkable is your failure to understand it.
  24. Wow! You cited a web page written by NASA for kids. And you managed to fail to understand it. The colour of the sky is not due to refraction. It is due to scattering. In the case of Mars, the particles of dust in the air are big enough to act as reflectors (rather than scatterers) and their colour shows up. Essentially brown martian dust makes the martian atmosphere brown.
  25. LOL It would be; now, where's the evidence that he's actually doing any of it? The fact is he is hindering research in so many fields
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