March 11, 2009

CRNano Chris Phoenix and MetaModern Eric Drexler Roundup

CRNano Increased Technical Content With Chris Phoenix
Chris Phoenix describes robotic control of molecular manufacturing without computation.

In high-volume molecular manufacturing, computers can't be used to control robots handling individual molecules, because computation requires too much power. However, computer-like control can be achieved without the use of computers, which means that robots can still be used where appropriate.

For some operations, it will be suitable to build single-purpose machines that can only do one thing. But for other operations, using externally controllable machines - robots - will make the nanofactory smaller and faster to build, and more flexible to use. A nanofactory using robots can easily build products of greater mechanical complexity than the nanofactory itself, and can build products that weren't designed when the nanofactory was designed and built.

But - and this is a key point - the controller does not have to compute those instructions in real time. The instructions can be a pre-compiled recipe. Do this set of 5,000 steps, and you get a cubic nanometer of diamond; do that set of 7,500 steps, and you get a nanometer of carbon nanotube. The lists of steps can be computed when the product is designed, and only copied from place to place when it is manufactured.

It takes energy to compute the lists of operations [for a nanofactory process] in the first place. But nano-built products will be highly repetitious; a recipe for a cubic nanometer of diamond will be re-used many times. The number of bits in a blueprint for a product may be vanishingly small compared to the number of atoms, and still specify the exact position of each atom in the product.

Chris Phoenix points out to blame the second law of thermodynamics (or any of the other physical laws) for the errors that creep into modern-day semiconductor fabrication is simply incorrect. Semiconductor fab errors are due to limitations in technology, not physics.

A Space Elevator update from a CRNano reader Tom Huffman.

Eric Drexler's Recent Technical Articles
Eric Drexler discusses computer aided design for structural DNA and protein nanotechnology.

Eric Drexler describes his dislike of the term nanobot.

A fifth article in the series on nanomaterials.

Are soft and hard machines at odds with each other? Surely not. Soft biomolecules and hard inorganic solids have worked together since a bacterium first succeeded in gluing itself to a mineral grain, and perhaps long before, at the origin of life itself. There is no gap between soft and hard nanomachines: The technologies form a continuum, and working together, they can form a bridge.

All the materials shown above are found in nature (ignoring the thorium in cerianite, which is mostly cerium dioxide). All but one, diamond, can be synthesized in water, at atmospheric pressure, near room temperature. Pyrite (“fool’s gold”) is often a product of biomineralization, and bacteria can synthesize magnetite as nanocrystals of controlled size and shape. Polymeric blocks with mechanical properties comparable to keratin could consist of any of a wide range of engineered proteins or other foldamers, and as can be seen, the value of Klm shifts from worst to best with a factor of 3 increase in block size.

As we explore implementation pathways to that lead toward advanced nanotechologies, it’s important to keep in mind that conditions for forming pyrite (and a range of other hard, inorganic materials) are compatible with soft-material technologies; these include macromolecular templates, crystal-growth promoters and inhibitors, and surface-binding molecules with diverse functions. Continued progress in engineering interfaces between macromolecules and inorganic crystals will be of critical importance.

The fourth article on nanomaterials which discusses lattice-scaled stiffness.

The Early Metamodern Nanotechnology Series
1. Modular Molecular Composite Nanosystems
Biomolecular engineering for atomically precise nanosystems

2. Toward Advanced Nanotechnology: Nanomaterials (1)
Why I’ve never advocated starting with diamond

3. Toward Advanced Nanotechnology: Nanomaterials (2)
Stiffness matters (and protein isn’t remotely like meat)

4. Self-Assembly for Nanotechnology
The virtues of self-assembly and the benefits of external guidance

5. From Self-Assembly to Mechanosynthesis
Mechanosynthesis begins with soft machines

6. Toward Advanced Nanotechnology: Nanomaterials (3)
Mechanical engineering meets thermal fluctuations

Eric Drexler's Articles with Videos of Nanomanufacturing
High-Throughput Nanomanufacturing: Small Parts (with videos)

High-Throughput Nanomanufacturing: Assembly (with videos)

High-Throughput Nanomanufacturing:
Assembling larger products (with videos)

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