Nitrogen

panamabob Wrote:
> Curious, wonder why its used in packaging to evacuate air in preservation?

Because it's inert and pretty damn cheap.

panamabob Wrote:
> For a fire to be a fire, it must have three things, heat, fuel, oxygen.
remove
> any of the three and the fire doesn't exist, instantly. If nitrogen was much
> lighter than air it would not work to evacuate air in a bottle or pouch...as
it
> happens at equal temps nitrogen has specific gravity of .967 compaired to
"1.0"
> of air and around 1.16 for oxygen ...but cooling it a bit would help it drop
> down.

I would suspect that they actually make it a vaccum then put the Nitrogen in or
something like that.

panamabob Wrote:
> no biggy, but since CO2 levels is not something you want to mess with
(usually
> less than 1%) and nitrogen (N2) is around 78% that it would seem Nitrogen
> would be a less critical gas to have circulating.... (oxygen is around 21%
and
> other trace gases make up the rest) or am I screwy here? :-)

I would expect the CO2 levels to be higher in the agricultural section of the
colony but how much higher I don't know. Extra CO2 will help plants grow but
not all that much and it does depend on the plant. Nitrogen you just gotta
have a bit of it for fixation (we could use fertiliser instead but having
fixation does help) and to bring the pressure up to 1 atm.

We could theoritcally do without Nitrogen using something like Argon instead or
but that would mean we get no fixation (not important if we use fertilisers).
We could also have a pure oxygen atmosphere but that causes some problems.
Either we have it at earth pressure and have a very big fire risk or we have it
at about 20% earth pressure with the same fire risk as on earth but requiring
some de-compression before entering the colony as well as being more sensitive
to loss of atmosphere.