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« Molecular Manufacturing vs. Peak Oil | Main | Precautionary Principle and Nanotechnology »

November 10, 2004

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» Nano Energy and "the Peak" from The Speculist
Chris Phoenix has some sobering thoughts on the potential coming energy crisis... If oil supply ever does fall below demand, we can expect prices to rise steeply. At this point, it could take years for alternative technologies to come online,... [Read More]

» Nano Energy and "the Peak" from The Speculist
Chris Phoenix has some sobering thoughts on the potential coming energy crisis... If oil supply ever does fall below demand, we can expect prices to rise steeply. At this point, it could take years for alternative technologies to come online,... [Read More]

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Michael Vassar

Silicon doesn't have the variety of forms of carbon, but I would be shocked if there wasn't some possible hybrid technique that would use silicon to manipulate carbon. Prehaps something like forming molds from Silicon and then using plasma deposition of diamond to fill the mold, then cutting out the diamond part, possibly with an x-ray laser or with a diamond knife, or possibly by reacting the non-desired parts with some chemical. Once diamond parts were assembled, they might be brought together mechanically possibly using simple manipulator tools that had been built from silicon, or by self-assembly.
Any idea why the Aono Atomcraft project didn't get funding to continue?

Michael Vassar

BTW, their lack of funding is a rebuttle to the current "if only Eric Drexel actually did experiments he would be credible" rhetoric.

John Michelsen

I studied these papers in great detail years ago. Conductivity is not a problem. But silicon is too mushy to make nanomachines out of. Diamond is the way to go.

Chris Phoenix, CRN


Michael: It's worth pointing out that all we know is that they didn't get _non-secret_ funding. Anyone know if Aono has "stopped publishing"?

John: Do you mean STMs can build 3D silicon shapes after all? And would they still be too mushy at cryogenic temperatures?

Chris

John Michelsen

With great effort, you could probably do precise 2D patterning in silicon. For 3D you need a material that won't just melt at the slightest touch like silicon and most other materials will. Temperature does nothing to make bonds stronger.

Brett Bellmore

No, but cryogenic temperatures CAN deny a surface the activation energy necessary to reconstruct, provided that simply depositing an atom doesn't provide the energy.

Another candidate material would be cubic boron nitride, which is strongly covalently bonded, and apparently resists reconstruction as much as, perhaps more than, diamond. The downside, of course, is that the chemistry is at least twice as complex, since it's a compound, not a single element.

Chris Phoenix, CRN


John: I know that temperature doesn't make bonds stronger. But can you explain more about the failure modes and conditions?

On boron nitride: part of what makes mechanosynthetic chemistry a pain is avoiding reconstructions. I'd guess (without study) that using two different atoms would reduce the opportunities for reconstruction, and so might make the chemistry easier or more reliable. And so might be worth doing even if you needed more tool tips.

Chris

Brett Bellmore

By the way, boron nitride really IS a good analog of carbon; Not only does it form a hard covalent solid, but there are also a whole class of boron nitride fullerenes.

Michael Vassar

Boron MNT might slow takeoff due to a lesser abundance of Boron vs Carbon. OTOH, it might be used to immediately build nanocomputers to run high power simulations followed by carbon MNT.

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