Comandante

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About Comandante

  • Rank
    Atom
  • Birthday 01/01/1987

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  • Location
    at home
  • Favorite Area of Science
    Physics, Chemistry
  • Occupation
    uni
  1. Gas extraction

    Could you please type full words? If people find it hard to read they won't respond to you. Apparently hexane works well but will leave about 10ppm residue in the oil once you get it out. Do you have a photo of your setup, I'd like to see?
  2. surviving free fall into the water from high altitude

    The guy in the video hurt his hands a bit I think, didn't seem like he had time to properly position them before impact. Nonetheless, nice jump. I wouldn't do it I've jumped from decent heights of about 10m or so some time ago, and I also noticed that once going down legs first I was also able to bend them outwards and so make a partial loop in the water whereby at the end of the dive my legs would be pointing upwards towards the surface and head would be pointing down, this way I prevented myself from going any deeper than I should be (had I maintained straight position) and I'm wondering if the same trick would work for high-alt jumps @forufes; I don't know about spinning yourself, maybe it helps for impact protection but how would you manage to swim out disoriented..
  3. Say a man was to fall out of an airplane from high alt (say 7km) (assuming no parachute!), what shape should he mold himself into to maximize his chances of survival on impact and how should he attempt to adjust his position once entered into the water. From what I read around in bits and pieces I got an understanding that once you reach the maximum velocity of free fall hitting the water would be similar to hitting the concrete due to its incompressibility, thus fatal in most instances. My question is, if you can adjust your shape/position so that you pierce the surface of the water on impact and survive it, what position would this be? Legs down first or? Also, would he black out due to rapid deceleration? And, should he survive the impact and not black out, how deep would he sink and would it be possible for him to hold enough air without that air being expelled out during the impact. Since coming up with numbers is probably a lot of work, qualitative opinions will help too. Overall, if everything humanly possible is done to improve chances of survival, what would those chances be, in qualitative terms? I understand that this is a bit of a physiology question too, admin may move the thread wherever is appropriate I dont mind.
  4. Teaching science through video games

    actually, that's a great idea. i think a large number of students would find something like this very useful. if future grants are possible i would concentrate on getting a contract with major game developer to improve graphics and playability, make it commercial. if not then this will work as the next best thing quite well i think. speaking of which, is this game to be commercial or free?
  5. were can i get some potasium iodide

    there's always some on ebay
  6. vinyl tubing pressure and LPG cylinder

    I figured as much from John's numbers, that's what I meant by something suitable But for some reason I suspect they won't have it, wouldn't be the first time these undersupplied hardware stores fail to provide. In that case I may have to look through the trash you mentioned Oh by the way, I found 2 online, but I'm not sure which one would be better, what do you think: this: http://cgi.ebay.com.au/2-75kpA-LPG-Regulator-Low-Pressure_W0QQitemZ320482001284QQcmdZViewItemQQptZAU_Barware?hash=item4a9e374184#ht_842wt_939 or this: http://cgi.ebay.com.au/Variable-Pressure-LPG-Regulator_W0QQitemZ320482002623QQcmdZViewItemQQptZAU_Barware?hash=item4a9e3746bf#ht_807wt_939
  7. vinyl tubing pressure and LPG cylinder

    That's what I would've expected. This burner is labelled as designed for LPG though, and from all the cylinders I inspected at the hardware store all were are at 3.3MPa, seemed like it's a standard. I'll go check out another store on Monday, they better have something suitable... Btw, this is the burner I have; http://cgi.ebay.com.au/LH0050-LPG-Bunsen-Burner-Slide-Collar-LPG-NEW_W0QQitemZ330422422011QQcmdZViewItemQQptZAU_Business_Industrial_Medical_Scientific_Equipment2?hash=item4ceeb609fb#ht_500wt_1182
  8. vinyl tubing pressure and LPG cylinder

    apparently the 3mm standard rubber tubing is suitable for use. i have some 2mm spare will try it when i get adaptor for the cylinder. will post how it went.
  9. Hey all, I'm trying to attach a Bunsen burner to an LP gas cylinder but I have problems finding the right adaptor and tubing for the cylinder. I have a piece of vinyl tubing of ~1.5mm wall width and I'm wondering if anyone knows how to calculate the maximum internal pressure that this tubing can withstand. I know the LPG cylinder is ~3.3MPa when full and it just looks to me like this tubing would not hold it so I don't want to try it just yet, would like some numbers. Any ideas?
  10. Supercritical Drying

    From what I understand, you pressurise a gas so it becomes liquid. Then use it for whatever you want to use it inside the pressurised vessel and after you finish you reduce the pressure in the vessel, which causes the liquid to change back to gas and evaporate. At least that's how it's used in supercritical extraction of essential oils by liquid carbon dioxide. Liquid CO2 is very good solvent for essential oils, very expensive procedure though.
  11. Difference between pure ethanol and 95%

    I buy 98% ethanol quite cheaply from hardware store, not even brand chem suppliers. Works great as burning fuel so you can probably use it for flame tests, it also feels very cold when poured over hand so I guess you may use it to some extent with dry ice, not sure though what exactly you have in mind. For most organic reactions however, it's doomed to fail - not that I myself have tried but from what I heard others report.
  12. Multiple space telescopes inter-coordinated?

    I think that that really depends on the age of the planet amongst other things, and if I'm not mistaken there is a good probability that there are old enough planets in the Milky Way to harbour intelligent life. But let's not hijack the thread.
  13. Essential Oil Extraction Method

    I do my extractions using steam distillation mostly, but I've recently been looking into liquid CO2 and how it all works, but I think you'd need a pressurised vessel for that. Enfleurage should probably be the best other way to do this.
  14. Insect Bite

    could be fire ant bite. just guessing
  15. largest number of results with a google query

    No I don't mind By the way, mrburns, I've checked your link yesterday and it gave me close to 26.5b, but I checked it again today and it gave me 14,7b ! This is weird, the results keep changing every day... by massive amounts! This is actually turning up more interesting than I thought.. might be an insight into the google engine ....Actually, I just checked, it gives different number on Australian search! I assume it would give different number depending on the country extension. See: http://www.google.com.au/search?complete=0&hl=en&safe=off&q=1+OR+2&btnG=Search gives 25.4b, and on .com it gives 14.7b. I like the the OR bit, but its inconsistent. It's odd to me too, because it sounds logical that OR should give more results if you include more characters/numbers and it doesn't.. :/ I wouldn't say that anyone has won this yet, I have a feeling someone will come up with higher count Google actually has quite a set of specialized search instructions, need to check it out..