# Comandante

Senior Members

300

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. ## surviving free fall into the water from high altitude

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. ## vinyl tubing pressure and LPG cylinder

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..
16. ## largest number of results with a google query

hmm try this; http://www.google.com.au/search?hl=en&q=inurl:*1&btnG=Search&meta=
17. ## largest number of results with a google query

ha! very nice edit; found higher; "inurl:*1" gives 26.66 billion
18. ## largest number of results with a google query

this might appear to be a pointless exercise and that's because it probably is but what is the largest number of google results that you can get using any possible input. i get 21,8 billion results with number 1, beat that!
19. ## Lab Glassware acquisition

I personally have no problems with Chinese made borosilicate glassware, it all depends on the type of experimentation you're going to do really. I do have a couple of original Pyrex pieces though for special experiments
20. ## iPhone App Development questions

I'm wondering about the same thing. I have some good ideas to code but I need to know more about the whole development process, have put that sort of, on hold, but now that you've mentioned it I'll keep an eye on this thread. Also, as there are tons of apps already out there, you really need to make sure that nobody has already made what you want to make, I figured that was the case with a few of my ideas
21. ## Genetic Manipulation 'Kit' (Do-It-Yourself)

this reminds me of biohacking, ever heard of it? I read an article somewhere... ah here it is: http://technology.timesonline.co.uk/tol/news/tech_and_web/the_web/article5400645.ece it's pretty interesting. If you ask someone on diybio.org they might be able to tell you more.
22. ## Firefox unable to load up ebay and some other sites

Ok, I installed Chrome and I can say it's not too bad Imported bookmarks from FF etc. I will also try reinstalling FF3 and see what happens with that. Thanks
23. ## simple column chromatography

I wanted to be able to separate some organic mixtures at home inexpensively and relatively efficiently so I thought I could make a column chromatography apparatus. Now, I figured that for my purpose I could use either glass or plastic tube (glass preferably) of about 2cm diameter or less, I could also mix up the mobile phase for transfer depending on the separation type and I could use a syringe top to produce some positive pressure, but one thing that I would like to know is this: Assuming that I could use some very fine sand for the stationary phase, I'd like to know what would be the largest particle size that could produce a useful separation and how long would the tube need to be to match this?
24. ## Firefox unable to load up ebay and some other sites

So I have this very annoying problem with FF3 and I think it has something to do with one of the web site formats, in particular the one that ebay uses, I don't know whether it's the java component or some other, but it simply does not want to load up a page and even if I somehow manage to get it to load, when I click on "next page" at the bottom of the current page the screen just moves up to the top of the same current page and nothing else happens, thus I cannot proceed to the next page. Interestingly, when I open it up with IE, generally it loads without problems, but clicking on the "next page" button does exact same thing as FF3. I believe my java plugin in FF3 is up to date, I can't seem to isolate the problem. To make the matters worse sometimes it works and sometimes it doesn't and I cannot seem to track down why it sometimes works and other times not. I run nod32 and zone alarm, I'm on WinXP and I hope I don't have to move over to Chrome any time soon since I like Firefox. Any ideas as to what might be causing this?
25. ## FF3 crashes

That's one problem that I have(had) with Firefox3 and I think I've isolated one possible cause. If you're by chance at uni (and seems you are I just checked) or use software called Blackboard (aka webct) (I know its popular amongst educational institutions worldwide) there is some sort of glitch that if you close the window while still logged in and then start FF3 again, it just crashes. Not always though, I don't know what the specific problem is, perhaps it's not related to logging in/out but I've noticed that as I haven't used it for a few months during the break I haven't had any problems, and then as soon as I started using it I've had few crashes in a week. Then it won't start until you stop it from processes window in task manager. See if that's any help. I now have another problem in FF3 which I'll introduce in new thread.
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