Re: [Sci.nanotech] Re: Just thinking crazy I guess :)


"Perry E. Metzger" <perry@xxxxxxxxxxxx> wrote:
Might I suggest that you spend the five minutes it would take to learn
the answers to your questions? This is the age of the internet. You
don't even need to go to a library first.

Searching the Internet has its place - but it is no substitute for
education and problem solving. Not all of Spaceman's question can be
answered by simple Internet searches. Some knowledge of strength of
materials and computational ability is required, among other things.

As for this notion of "vacuum" you have in this context, I suggest you
think for a moment about the mean free path of gas molecules at 300K,
and compare that to the size of a buckytube.

I'm not sure what you are trying to suggest here - buckytubes can come in
(I believe) any size radius or length. I suppose at some size level they'd
be called (and considered) cylindrical graphite sheets - though I don't
know if anyone has defined where that transition point occurs.

An object with something inside it has more mass, not less, than the
object without something inside. Mass is not reduced when something is
bouyant. I suggest going back to introductory physics class.

I'm putting on my moderator cap to address the above:

The last sentence was needlessly insulting (it suggests the Spaceman has a
learning problem). I should point out that this newsgroup is open to people
of all ages and educational attainments from around the world who can read
and write English. It may be that Spaceman has not yet (or never) had an
introductory physics class, but does have a strong interest in science. Or
simply made some mistakes which, had they been pointed out more
diplomatically, been educational rather than confrontational.

As I stated, I also have thought about the vacuum filled version.
but one difference would be a gas without actual pressure on the
walls inside could actually help with the strength of the structure
where a vacuum would actually create a stress in the structure.

So how would a buckytube crush under 1 atmosphere of pressure? Or even
far, far more? Even without doing a calculation it is pretty obvious
to the casual observer that isn't going to happen. If it isn't obvious
to you, you don't know enough to make informed speculations on this
topic.

What of a buckytube one meter in radius? Or merely one millimeter in
radius? I know I'd have to look up the strength of, say, graphite at least
and consult one of my strength of materials text to make sure I was using
the correct equation for stress on a diametral section.

.