On Wednesday 08 July 2020 12:47:17 N wrote: > On Wed, 8 Jul 2020 12:15:21 -0400 > > Gene Heskett <ghesk...@shentel.net> wrote: > > On Monday 06 July 2020 00:43:30 Chris Albertson wrote: > > > On Sun, Jul 5, 2020 at 3:33 AM andy pugh <bodge...@gmail.com> wrote: > > > > You say this a lot, but I have never heard anyone else say it. > > > > What is your source? > > > > > > THis might be a "Chemistry 101" question. It should be easy > > > enough to figure out except that I last studied this stuff in the > > > last 1970s > > > > > > We all know that burning carbon produces a lot of heat. The > > > chemical equation is > > > C + O2 --> CO2 -394 kJ / mole > > > > > > The corresponding equation of aluminum is > > > 4Al + 3O2 --> 2Al2O3 -1676 kJ/mole > > > Aluminum produces more heat per mole than carbon and also more > > > heat per gram than carbon. It would make good fuel except for > > > combustion stops once the oxide layer is formed. > > > > > > Next, I looked up the specific heat of aluminum. It is very close > > > to 1.0 kJ / (Kg K). So it only takes 1 Joule to heat one gram of > > > aluminum one degree K. > > > > > > So there is plenty of energy and the metal is also easy to heat. > > > But what we don't know is the fraction of aluminum that is > > > oxidized. You could figure this out if you had a good enough > > > scale and could collect all the chips. We could see how much mass > > > the chips gained from the added oxygen. > > > > Difficult to do since the chips would have to be collected in an > > inert atmosphere, ... > > If you want to avoid oxidation you could use inert gas, maybe nitrogen > or co2 as then welding? > Then you have to worry about leaks, since both are lethal. And co2 might not be a useable atmosphere since it by definition is one carbon atom and two oxygen atoms, The chemical activity of the alu could possibly contaminate the results by borrowing an oxygen atom from the co2, leaving co, and thats not healthy either because taking the victim to fresh air takes too long to restore the blood oxygen to life supporting levels. Fresh air is a much quicker life saver with nitrogen because it doesn't bind in the blood like co, so the victim can be re-oxygenated much quicker.
We in broadcasting commonly use dry nitrogen as line pressurizer at 2 or 3 psi to keep rain water from migrating in thru small leaks. But in the event we have to vent several hundred feet of coax to do maintenance on it, I have always put a hose going outside from the venting valve in order to not load up the interior of the building with the nitrogen. 2000 feet of 6.125 75 ohm line contains around 2 big bottles of dry nitrogen and can be quite lethal as it has no odor. For that reason, we often have a small container of ethyl mercapton in the path from the tank to the line. 1 molecule of that per cubic foot can be smelled by the human nose on the first breath. > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
