From the category archives:

Nanoscience

Effective Concentration in Self Assembly,
Catalysis, and Mechanosynthesis (1)

March 22, 2009

I find that the concept of “effective concentration” helps to clarify my thinking about molecular processes that include catalysis, self assembly, and mechanosynthesis. The concept applies most directly to reaction rates, and it uses ordinary, solution-phase processes as a reference point.
Reactant concentration and reaction rate
In a relevant and typical case, molecules of type A react [...]

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A High-Performance Polymer
for Nanosytems Engineering

March 19, 2009

Molecular objects made of a nylon-like, high-performance polymer are among the most intricate and functional nanostructures in existence today, and they’re being used to develop increasingly advanced, atomically precise nanotechnologies. This high-performance polymer is really more of a construction kit: Its monomeric parts can be bonded and folded to build atomically precise structures that self-assemble [...]

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Pyrite Nanomaterials for Solar Photovoltaics

March 13, 2009

A new paper in the journal Environmental Science & Technology assesses the requirements for scaling solar photovoltaic systems to the terawatt levels needed to supply electric power on a global scale. The authors identify iron pyrite, FeS2, as an attractive but unconventional alternative: The raw materials for pyrite aren’t scarce, and both the energy and [...]

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CAD for Nanoengineering: DNA, proteins, and search-intensive design

March 11, 2009

In my previous post I discussed some basic design concerns that arise with atomically precise structures, and focused on materials having crystalline order. However, the ability to make structures like these is now extremely limited. Because they can’t yet be built systematically from smaller building blocks, structures of this general are more likely to be [...]

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How Nanotubes Grow: A theory that has nothing to do with reality

February 24, 2009

Today I read a report of a controversy about the growth of carbon nanotubes. There’s an entirely bogus theory involved, two scientists using harsh words, and another scientist taking the hit. Behind the controversy is another theory that I think is almost certainly correct. The real story, though, is in the reporting itself. [See update [...]

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What’s in the Vault?

February 22, 2009

They’re called “vaults”. They‘re in our cells, and in those of every* plant, animal, and fungus. Like ribosomes, they’re atomically precise self-assembled structures made of protein and RNA, but they’re big and hollow, large enough to pack many ribosomes inside. They’re relatively simple and symmetric: A vault consists of two identical halves, each consisting almost [...]

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Nanomachines: How the Videos Lie to Scientists

February 10, 2009

Sound physical inference from an illusory premise

Don’t let this animationfool you about the physics!

By now, many scientists have seen videos of molecular-scale mechanical devices like the one shown here, and I have no way to know how many have concluded that the devices are a lot of rubbish (and have perhaps formulated an unfortunate corollary [...]

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Toward Advanced Nanotechnology:

Nanomaterials (3)

February 8, 2009

Mechanical engineering meets thermal fluctuations
Thermal fluctuations distort nanoscale structures, and this makes them an enemy of nanotechnologies that rely on precise mechanical motion. Indeed, if one were to set aside design and calculation and instead substitute guesses (I’m not naming guilty parties here), one might suppose that this would prevent nanomechanical engineers from designing reliable [...]

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Productive Nanosystems: The Movies

January 30, 2009

In his comment on Molecular Machine Assembly: The Movie, Drew Whitehouse reminded me of a set of excellent animations of biological productive nanosystems, work done by Drew Berry. These videos are based on scientific data describing molecular structure and function, and from what I’ve seen, Drew Berry’s work is the best of its kind. Below [...]

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Molecular Machine Assembly: The Movie

January 12, 2009

I just watched an extraordinary set of videos that shows the assembly and operation of an intricate molecular machine. Beware, though: these highly realistic videos lie — but because they must!

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The Nobel Prize for Technology

January 8, 2009

We usually think of Nobel Prizes in physics, chemistry, and medicine as celebrations of scientific discovery, yet prizes are often awarded not for discovery, but for technological innovation. This is entirely proper, as you can perhaps see from the above excerpt of Alfred Nobel’s will.
I surveyed the awards since 2000 to see which were granted [...]

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Molecular Assembly Lines

January 5, 2009

Cells use what are, in effect, molecular assembly lines to manufacture a range of complex molecular products. Biochemists recently learned in greater detail how these biomolecular assembly lines work, and are considering how to string devices together to make artificial machines that work the same way.

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