So, i was musing on carbon tubes. Specifically
how to make a nice yard or more, single length tube.

How to coax the carbon to take our choice over its own?

In my head, almost fully outlined popped this:
A tiny chamber filled with carbon dioxide, kept active
via laser to stop it settling on the walls.

A silicon partition with six laser made perforations
(single carbon atom sized) in a hexagon pattern.

And a pressure control between the two, so that when
the holes are filled the difference encourages it to
progress through to the ordered side.

I guess this won't work like this, maybe the carbon
will behave better in a liquid mixture?

Anyhow, I'm still interested in why it won't work
Fire away.

mike <mikespam@invariant.freeserve.co.uk> writes:
So, i was musing on carbon tubes. Specifically
how to make a nice yard or more, single length tube.

I presume you mean a "single wall carbon nanotube".

How to coax the carbon to take our choice over its own?
I'm not clear what you mean by that.

In my head, almost fully outlined popped this:
A tiny chamber filled with carbon dioxide, kept active
via laser to stop it settling on the walls.

I'm not clear what you mean by that, either. A gas like CO2 doesn't
"settle on walls" at normal temperatures, at least not generally
speaking. (There are circumstances in which some CO2 could be adsorbed
into surfaces, of course, but that's clearly not what you have in mind
here.) I'm also not sure what "kept active via laser" would mean.

A silicon partition with six laser made perforations
(single carbon atom sized) in a hexagon pattern.

A carbon atom is order of magnitude the same size as a silicon
atom. To make a "perforation" this size in a silicon surface would
imply somehow removing individual silicon atoms with a laser.

Since an >individual atom is on the order of 100pm (one angstrom) across, you
would need a laser with a wavelength on that order of that length.
#

Besides, it isn't clear you could even get the Si atoms to
reliably absorb the x-rays -- they'd likely pass through the surface
instead.)

Even assuming you could somehow remove single Si atoms by this utterly
impractical means, you could not drill a single atom wide hole through
an Si surface -- the Si atoms would just migrate and close your hole
up.

And a pressure control between the two, so that when
the holes are filled the difference encourages it to
progress through to the ordered side.

I have no idea what this means, or what relationship it might have to
your mention of CO2 gas or your "hexagonal pattern" "perforations".

I hypothesize that you somehow think that CO2 could somehow be forced
up to the magic holes you imagine you drill, the carbon atoms would

somehow magically detach from their bound oxygens, that following this
the carbon would somehow not instantly bond to the Si,

and that somehow by forcing streams of C atoms out the "other side" in a
hexagonal pattern they'd somehow magically form a "nanotube". (Why a
hexagonal pattern? Perhaps you've seen a sketch of a graphene sheet in
a magazine and fixated on the hexagons.)

This idea is more or less as plausible as the notion that you could
make humans by forcing bits of homogenized cow through a short slot in
a piece of sheet steel.

Perhaps my hypothesis on what you mean is wrong, but I can't think of
any mechanism by which a "hexagonal pattern" of "perforations" in some
Si is going to make you a SWCNT.

I guess this won't work like this, maybe the carbon
will behave better in a liquid mixture?

What do you imagine a "liquid mixture" of "carbon" means? Do you think
that somehow if you can make "carbon" into a "liquid" that it will
work better in your nano-scale pastry decorating tube?

(For reference, you can't actually make carbon into a liquid anyway --
at least, not at temperatures below 4000 kelvin and very high
pressures.)

Perhaps you imagine using liquid CO2 would be better for your purpose
than gaseous CO2 -- the answer is no, it won't.

It makes no difference what phase the cow homogenate is in
when you throw it at a small slot in some sheet steel --
you still won't get a person extruded.

Anyhow, I'm still interested in why it won't work
Fire away. :-)

It won't work because none of it makes any sense at all.

It isn't even a proposal

-- it is a series of odd and not particularly plausible
ideas with no connection between them, none of which seem to have
anything to do with carbon nanotubes. I had to guess at what you were
talking about and even then it was completely implausible.

----------------------------------------------------------------------
(As an aside, I'm rather disappointed in the moderators for letting
"Mike"'s message through.

Perhaps the assumption is that since there are no postings these days,
absolutely anything, no matter how strange, should be
forwarded.

However, my suspicion is that no good content is posted precisely
because the bizarre content has driven serious people completely
away. (Were it not for the date on the original message, I would have
assumed it was an April 1st prank.)

Of course, it appears to be too late for sci.nanotech since the
content is now approximately one post of this last post's quality per
month, but perhaps a lesson can be drawn for other future fora.)

----------------------------------------------------------------------
(As an aside, I'm rather disappointed in the moderators for letting
"Mike"'s message through.

Perhaps the assumption is that since there are no postings these days,
absolutely anything, no matter how strange, should be
forwarded.

However, my suspicion is that no good content is posted precisely
because the bizarre content has driven serious people completely
away. (Were it not for the date on the original message, I would have
assumed it was an April 1st prank.)

On a dark an' dismal Tue, 01 Apr 2008 21:31:11 -0500, in flickering lamplight,
"Perry E. Metzger"
perry@piermont.com> scribed with phoenix qill :

Well.
I know i said fire away, but i wasn't expecting
a flame. The moderators are usually careful
about that....

mike <mikespam@invariant.freeserve.co.uk> writes:
So, i was musing on carbon tubes. Specifically
how to make a nice yard or more, single length tube.

I presume you mean a "single wall carbon nanotube".

Yes, that's what i meant.

In my head, almost fully outlined popped this:
A tiny chamber filled with carbon dioxide, kept active
via laser to stop it settling on the walls.

I'm not clear what you mean by that, either. A gas like CO2 doesn't
"settle on walls" at normal temperatures, at least not generally
speaking. (There are circumstances in which some CO2 could be adsorbed
into surfaces, of course, but that's clearly not what you have in mind
here.) I'm also not sure what "kept active via laser" would mean.

Right, first, i don't really know where the carbon dioxide slipped into
the text. Sorry for that, was intended to be all carbon.
The other things like 'normal temp' you refer to?
It's hot, that's what the laser's for, to 'keep it active' a gas.

A silicon partition with six laser made perforations
(single carbon atom sized) in a hexagon pattern.

A carbon atom is order of magnitude the same size as a silicon
atom. To make a "perforation" this size in a silicon surface would
imply somehow removing individual silicon atoms with a laser.

Which i have read has been done. [might not be silicon, though]

Since an >individual atom is on the order of 100pm (one angstrom) across, you
would need a laser with a wavelength on that order of that length.
#

As i understand it, the trick is to use two or more lasers at half strength,
creating rings like a ripple in a pond.

#
Besides, it isn't clear you could even get the Si atoms to
reliably absorb the x-rays -- they'd likely pass through the surface
instead.)

Okay, what would you suggest?

Even assuming you could somehow remove single Si atoms by this utterly
impractical means, you could not drill a single atom wide hole through
an Si surface -- the Si atoms would just migrate and close your hole
up.

They would move that fast? I thought we would have them vibrate
and eventually seal the holes, but i was assuming months.

And a pressure control between the two, so that when
the holes are filled the difference encourages it to
progress through to the ordered side.

I have no idea what this means, or what relationship it might have to
your mention of CO2 gas or your "hexagonal pattern" "perforations".

To colour it in a little, all it meant was keep the feed side at a slightly
higher pressure, thus encouraging the carbon trapped in the holes to
move through.

I hypothesize that you somehow think that CO2 could somehow be forced
up to the magic holes you imagine you drill, the carbon atoms would

Apart from the dioxide muck up in my first post,

for which i have
already apologised and will not keep doing so, 'coax' is the word i
used because i knew 'forced' was inappropriate.
The Carbon atoms will eventually enter them, if energy is
supplied when things wind down.

[Don't call them magic holes again, please.]

somehow magically detach from their bound oxygens, that following this
the carbon would somehow not instantly bond to the Si,

Let them, Next time the laser passes over they will be released.

Or don't use Silicon, another reason it's a bad choice.
What do you suggest as an alternative?

and that somehow by forcing streams of C atoms out the "other side" in a
hexagonal pattern they'd somehow magically form a "nanotube". (Why a
hexagonal pattern? Perhaps you've seen a sketch of a graphene sheet in
a magazine and fixated on the hexagons.)

Why not a hexagon? It had to be something, and that just dropped it place.
Do you have a specific reason it cannot be one?

All that's important is providing the carbon with plenty of
opportunity to bind in some stable ring formation, and still be open
to linking to more from the feed side.

This idea is more or less as plausible as the notion that you could
make humans by forcing bits of homogenized cow through a short slot in
a piece of sheet steel.

This doesn't relate, in any way. I am talking about atoms, and that
'notion' above, as you call it is not.

Perhaps my hypothesis on what you mean is wrong, but I can't think of
any mechanism by which a "hexagonal pattern" of "perforations" in some
Si is going to make you a SWCNT.

You have missed the point and focused on trivia.

Right at the start was the warning that this was unpolished thoughts,
and i was posting to spark off some feedback.

I guess this won't work like this, maybe the carbon
will behave better in a liquid mixture?

What do you imagine a "liquid mixture" of "carbon" means? Do you think
that somehow if you can make "carbon" into a "liquid" that it will
work better in your nano-scale pastry decorating tube?

It means exactly what was said, a mixture, not a compound, that
forms a liquid.
How you extrapolated to get that i don't want to know.

(For reference, you can't actually make carbon into a liquid anyway --
at least, not at temperatures below 4000 kelvin and very high
pressures.)

I'm glad i didn't suggest it then :-)

Perhaps you imagine using liquid CO2 would be better for your purpose
than gaseous CO2 -- the answer is no, it won't.

You imagined that, not me.

It won't work because none of it makes any sense at all.

Yet you still responded to it?

It is a suggestion to build nano tubes from carbon gas, by
letting it bond only in set points.

Or perhaps as i have posted here many times, the moderators
know i wouldn't post senseless rubbish,

I suggest that you re-read the beginning of my original post and
then decide if that was justified.
Still, not too bad considering you didn't understand it.

mike <mikes...@invariant.freeserve.co.uk> writes:
On a dark an' dismal Tue, 01 Apr 2008 21:31:11 -0500, in flickering
lamplight,
"Perry E. Metzger"
pe...@piermont.com> scribed with phoenix qill :

Well.
I know i said fire away, but i wasn't expecting
a flame. The moderators are usually careful
about that....

I believe I stuck pretty strictly to the facts. You may not like the
facts, but that does not make the posting a "flame".

I believe I stuck pretty strictly to the facts. You may not like the
facts, but that does not make the posting a "flame".

You're a smart guy, Perry, so please don't insult *my* intelligence by
pretending that there's a non-insulting interpretation to the little
post-script you attached to your initial response.

I also stand behind Jim in his approval of Mike's initial message in
this discussion thread, for all the reasons he listed. I moderate
mostly based on topicality, not the correctness of the post; as Jim
notes, that approach did not work either.

I remember this forum's early days, including a large number highly
speculative posts which you would not care for.

Here is a suggestion, Perry: If the present level of posts does not
meet your standards, you are perfectly welcome to submit your own
posts which do.

the text. Sorry for that, was intended to be all carbon.
The other things like 'normal temp' you refer to?
It's hot, that's what the laser's for, to 'keep it active' a gas.

A silicon partition with six laser made perforations
(single carbon atom sized) in a hexagon pattern.
A carbon atom is order of magnitude the same size as a silicon
atom. To make a "perforation" this size in a silicon surface would
imply somehow removing individual silicon atoms with a laser.

Which i have read has been done. [might not be silicon, though]

mike <mikespam@invariant.freeserve.co.uk> writes:
Well.
I know i said fire away, but i wasn't expecting
a flame. The moderators are usually careful
about that....

I believe I stuck pretty strictly to the facts. You may not like the
facts, but that does not make the posting a "flame".

Right, first, i don't really know where the carbon dioxide slipped into
the text. Sorry for that, was intended to be all carbon.
The other things like 'normal temp' you refer to?
It's hot, that's what the laser's for, to 'keep it active' a gas.

Carbon doesn't generally become a gas until well past
4000K. Regardless of how you heat it, you will end up with something
that will more or less destroy anything it comes into contact
with.

Furthermore, even once turned into a gas, a monatomic form is
not energetically favored until very high temperatures, where
entropy effects overcome the exceptionally strong carbon-carbon bond
energy, thus making your proposal even more unlikely.

A carbon atom is order of magnitude the same size as a silicon
atom. To make a "perforation" this size in a silicon surface would
imply somehow removing individual silicon atoms with a laser.

Which i have read has been done. [might not be silicon, though]

I assure you that no one has yet found a way to remove single atoms in
precisely defined (that is, defined down to an atomic radius) positions
with a laser.

You are referring to interference effects. Such effects do not involve
the creation of fields with a characteristic length tens of thousands
of times below the wavelength of the light in use. Again, what you
propose is quite clearly impossible without the use of frequencies far
beyond the ability of current technology to control.

#
Besides, it isn't clear you could even get the Si atoms to
reliably absorb the x-rays -- they'd likely pass through the surface
instead.)

Okay, what would you suggest?

I have no suggestions -- you are attempting to perform impossible
tasks. Even if I wished to, I could not provide you with ways to
perform them.

Si atoms would just migrate and close your hole up.
They would move that fast? I thought we would have them vibrate
and eventually seal the holes, but i was assuming months.

Depassivated Si surfaces are notoriously reactive because they are
very energetically disfavored. The surface will spontaneously
re-arrange to minimize its energy.

If you could magically keep it from vaporizing what it came into
contact with, it would react instantly with depassivated silicon -- it
would not "move through" holes.

[Don't call them magic holes again, please.]

Why not? You need magic to make them, and apparently they have
the magic property of extruding nanotubes out the other side.

Any laser capable of breaking a carbon-silicon bond would melt or
vaporize the entire silicon structure. In any case, no carbon atom
will ever travel through an impossible-to-produce single atom wide
hole in a layer of silicon because, were it not so energetic as to
damage the hole itself, it would *always* bond to the Si long before
it could get through the hole, so it essentially wouldn't matter how
often you try.

Why not a hexagon? It had to be something, and that just dropped in place.
Do you have a specific reason it cannot be one?

Why not make it into a pentagon, or a tic tac toe grid, or any other
pattern? Even if you could get single C atoms to emerge in a
hexagonal pattern, what is special about a hexagon? Again, perhaps you
are under the misapprehension that a single wall carbon nanotube is
hexagonal in cross section, but it is not, so what is the purpose of a
hexagonal pattern?

Regardless, the idea is implausible. This isn't chocolate frosting
being forced through a pastry tube -- the carbon atoms, even if you
could get them to emerge from your hexagon, will not nicely queue up
and bond to each other, in a hexagonal pattern or in any other pattern.

All that's important is providing the carbon with plenty of
opportunity to bind in some stable ring formation, and still be open
to linking to more from the feed side.

Why would the carbon atoms bond in any particular shape whatsoever?
If they could make it through the holes at all, they'd be arriving in
a temporally randomized pattern, with wildly different energies
(following the Boltzmann distribution for a substance at that
temperature) and would almost certainly leave the holes with quite
uncorrelated trajectories. They would not be within a typical
carbon-carbon bond length of each other, and if they became close
enough to each other there would be no particular reason for them to
form any particular pattern of bonding.

This idea is more or less as plausible as the notion that you could
make humans by forcing bits of homogenized cow through a short slot in
a piece of sheet steel.

This doesn't relate, in any way. I am talking about atoms, and that
'notion' above, as you call it is not.

It does relate, in that it is more or less an equally plausible idea.

It won't work because none of it makes any sense at all.

Yet you still responded to it?

Correct. I've got the bad habit of explaining why incorrect ideas are
incorrect when I encounter them.

I'm afraid that the archives, which are astonishingly complete, show
no previous postings from your account. Perhaps you've posted in the
past from other accounts, but I see no reason to assume the moderators
would be able to know that.

I suggest that you re-read the beginning of my original post and
then decide if that was justified.
Still, not too bad considering you didn't understand it.

I understood what you were, more or less, proposing. Unfortunately,
the proposal has no germ of a plausible idea within.

Carbon vaporizes at a high temperature, which would destroy the silicon
barrier
you want to feed it through. (It is estimated to melt above 4500 deg K
http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA112977>).

If you want reactive carbon, it would be easier to start with a reactive
carbon-containing molecule, and arrange for it to decompose or react at the
site you want it too. Lasers could be used to cause or help the reaction.

Silicon is not so rigid at this scale as Perry mentioned. There are
silicon-containing materials called zeolites, with interesting small holes
(<http://en.wikipedia.org/wiki/Zeolite>) and you are right that molecule-sized
holes can make interesting reactions occur (see
http://www.che.caltech.edu/groups/med/catmat.html> for an overview).
Having small holes, makes them a bit delicate at higher temperatures though.

So the problem is then to find the right molecules and the right sort of holes
and the right conditions for the reactions you want to happen.