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Everything posted by entropydave

  1. ...seems that the moderator has sensibly removed the remarkably stupid posting that was made by "ass_pirate30" whoever he is.... thanks Mod!
  2. Yup, still no input! ...and I thought you chaps had some answers.....!
  3. Hi, I did have a piece of shareware that allowed one to simulate galaxy collisions - for the life of me I can't find it now! I do have one called "galaxy32.exe" but it is 10 years old and not the one I was using.... It was freeware BTW. If anyone knows of the s/ware (or equivalent) can you please let me know? thanks dave
  4. well, this must be a veryunpopular topic or question! No responses at all!
  5. I went to a lecture yesterday given by Prof Bernard Pagel on neutrinos and we briefly touched on young galaxies, notable 1 Zwicky 47 which is around 500 million years old and he remarked that the metallicity of the stars were pretty much zero - I briefly discussed with him that I cannot accept that there were huge blobs of primordial matter, from the Big Bang, that was still unseeded by elements higher than Li. He agreed that this was a mystery and that maybe there was some other answers, like all that we see are very large, very old white stars mixed in with small amounts of 2nd & 3rd gen stars. I cannot see how a large and very old white star could remain on the HR diagram without long ago supernovaing or cooling to form neutron stars or whatever.... Any ideas? Because he sure didn't!
  6. Oh, well that's ok then... please note, not a "25 year old man", or "a 27 year old man" (or indeed woman) but a "26 year old man" ...sounds like the sort of thing a 13 year old would say!
  7. Taenite is high in nickel, (>10% or so) Kamacite is lower in nickel - or the other way around!
  8. ferric chloride is just as good - degrease a polished slice, use a swab of cotton wool to apply the ferric chloride and then rinse v. thoroughly with deionised water, then a rinse in 95% isoprop, then a gently bake at about 110- 120 deg c. That'll work nicely!
  9. Thanks jdurg! Trouble is, I would have definately inhaled the thorium oxide - I remember the white powder on my specs! There was a cloud of white dust because the silly beggar shook it up and then puffed it...
  10. crap. never even thought about getting it checked.... that's all I bloody need! good advice - I think I should take it.
  11. ...well, not a friend exactly, but we are talking about a fellow classmate - remember it clearly - would have been about 1976/77. One would gently squeeze the washbottle and the Rn gas would be puffed out.... I don't smoke and I don't have any coughs or bronchial problems....yet. Should I raise this long-ago event with my GP? I have been dealing with precancerous colonic polyps for 3 or 4 years ("drug and scrape"...)
  12. ...I just recalled an incident that happened when I was at school, about 30 years ago or so.... we used to have a Radon generator which was a plastic wash bottle with a load of Thorium oxide (or some white, thoriated powder, presumably Thorium oxide). You left it to accumulate Radon gas and would use in certain practicals in physics. I remember my friend shakking it up and puffing the boody thing in my face - I must have inhaled a cloud of this stuff.... thank heavens for Health & Safety regs, eh?
  13. I'd melt it and electrolyse it and get some pure metallic Ra....(I know I know, it's mixed with ZnS....!)
  14. Yep, I have just measured it from behind - gold is a pretty effective absorber of gamma and it is about 0.5 - 0.75microSv/hr. Judging by the link given above - I think that sitting on a granite bench is more of a problem! Especially to one 'nads!!
  15. I measured thru the glass - no beta and a little gamma will escape...!
  16. Hi everyone, just a query about my ol' 1940s gold Ebel wristwatch.... not, I know they used radium salts for the luminous hands,but I am surprised to see it measures at 15 microSv/hr..... I presume that's normal, Just wanted to see what you all thought!
  17. Hi, ...was just pondering the endlife of a neutron star.... presuming they rapidly rotate, and that they will absorb ISM and emit radiation, what happens in the long term with these stars? Do they evaporate or grow due to ISM dust collection? I also wondered whether or not the absorption of a photon onto a neutron would/could change it into a proton, and if so, what energy photon would do that? You'd think I'd have better things to think about, n'est pas?
  18. Yep, as a astrophysics student I concur. Even if they had short 1/2 lives, I suspect we'd detect the daughter nuclei?
  19. Yeah, wouldn't it? Jeez, nasty but beautiful.... like some women I knew!
  20. ...I'd like to get some Ra but not a bunch of watch hands from the 1940s!!! Any ideas? I like the way the Curies had test tubes full of polonium salts and soem fluorescent stuff (a Zn compound?) and would entertain their guests with the 'eerie glow'. In fact, wouldn't mind some Po, but the spark plugs that had it as part of their contacts (ionized the air so it would 'spark' easier was the logic) have all now decayed to daughter products....!
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