On 03/02/2016 07:58 PM, Linus Torvalds wrote: > On Mar 2, 2016 7:34 PM, "Steve" <[email protected]> wrote: >> >> SMB: Would be interesting to see if a polynomial of 21% of the oxygen >> factors and 79% of nitrogen factors comes close (enough) to the air >> specific one. > > See some of my "Google is great at graphing" emails.
Yup. That was the next email after the one I posted. Note to self. Really should read all outstanding emails first. Really. > > Short version: yes, the linear mixing seems to give extremely good > results at least for air (which is the only one we have independent > tables for). There are bigger differences just between the air tables > on Wikipedia and baue. > > In fact, if you plot the baue air polynomial and the "air mix" > polynomial at the same time, you get an almost *perfect* match to 300 > bar. That would agree with chemistry theory about gas partial pressures. > > After that it diverges a bit, but that seems to be because the oxygen > polynomial really ends up being bad at 300+ bar. > > You can trivially test yourself: just paste this into google: > > y = > 0.9994355774568318-0.00035668306234655186*x+0.00000218474273138185*x^2+5.8403793405e-9*x^3-2.780101081e-11*x^4+3.144563e-14*x^5, > y = > 0.21*(1.0002231211532653-0.0007471497056767194*x+0.00000200444854807816*x^2+2.91501995188e-9*x^3-4.48294663e-12*x^4-6.11529e-15*x^5)+ > > 0.79*(1.0001898816185364-0.00030793319362077315*x+0.00000327557417347714*x^2-1.93872574476e-9*x^3-2.7732353e-12*x^4-2.8921e-16*x^5) > from 0 to 500 > > where that first "y=" is the polynomial from the "air" table at baue, > the second "y=" is the "air mix" from the polynomials for oxygen and > nitrogen. > > They are literally on top of each other. > > In fact, it's *such* a perfect match up to 275 bar that I wonder if > the baue numbers aren't based on a linear mix. <<grin>> That would be a more "perfect" explanation. Each fall my professor would say "What we taught you last year is just an approximation. This year we'll explain how it really works." I suspect they same thing to the master and doctoral candidates. > > In other words, it's possible that one or more of the the baue tables > aren't entirely experimental. Mayeb the baue pure gas tables are > experimental, and the air table is from a linear mix of those? > > Regardless, the linear mix looks really good. When you compare it to > the Wikipedia numbers, it's still pretty close. So everything lines up > pretty well. > > Linus > _______________________________________________ subsurface mailing list [email protected] http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
