[TML] Environmental domes

[shadow at shadowgard.com]

On 5 Sep 2007 at 3:08, Jerry W Barrington wrote:

> Suspension is possible, but at the University I attended, they had an
> Olympic size swimming pool under a dome that was inflated.  Fans kept the
> pressure inside slightly higher than outside.  It even had cables on the
> *outside* to contain it.  The differential only needs to be somewhat more
> than the weight of the dome.  Thus 1 PSI higher inside pressure will support
> a dome of almost 1 pound per square inch.  In this way, it doesn't matter
> much how big the dome is, except that the cables end up with a lot of
> tension on them.  Kind of a reverse-suspension system.

That's one of the designs that doesn't scale up well. Internal and 
external pressures change with altitude. As soon as you get city 
sized or so, you've got significantly skewed stresses.

> As for American counties, there's a lot of variation depending on where you
> are.  Brewster Co., in SW Texas next to Mexico covers 6194 sq mi (16039 sq
> km).  That's larger than the 3 smallest states!  The "average" county
> (Texas' area/245 counties) is 1069 sq mi.
> 
> [Yes, I was geek enough to go do the research just for this post.]

So was I. But mine was limited to unrolling an old base map of the 
state and looking for a large county that was roughly rectangular for 
ease of measurement.

And doing a google search for "largest county".

> On 9/4/07 9:40 PM, Leonard Erickson wrote:
> 
> > One such suggestion was for Saturn or some other gas giant with a
> > reasonable gravity at an altitude where the atmospheric pressure is
> > near normal. The proposal allowed it to be built as large floating
> > "cities" that could eventually be joined to form a shell.
> 
> If you're keeping it up there by any means other than physical support, it
> will be gravitationally unstable.

They are *floating* in the atmosphere. As in "bouyancy". So 
gravitational stability isn't relevant. They are supported. 

Just make sure the source of bouyancy doesn't fail. At least things 
would bre distributed enough that if a section fails, it's local 
disaster.



--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com