On Mon, 20 Aug 2001, Damien Broderick wrote:
> George Whiteside is the leader (with ourselves!) in the field of molecular
> self-assembly as it actually occurs within our current understanding,
> particularly from a chemistry perspective, and nanotechnology, i.e.the
> understanding of phenomena at the nanoscale dimension and mechanisms by
> which nanoscale molecules interact with one another, is precisely his field
> of expertise.
Oh, sure, we're all cranks and buffoons here.
> Splitting hairs with the ATP argument. ATPase enzyme is embedded in a
> biological membrane and is driven by energy produced in the form of a
> chemical gradient through the build-up of hydrogen ions, hence it is
> chemical energy used to drive the rotation of the protein shaft. Magnetic
> field generation occurs during electron transport, which is not occurring
> during this process.
Splitting hairs with electric motors being impossible at nanoscale:
magnetic field generation does not occur in an electrostatic motor,
because a charged multipole gets yanked around by a synchronously
oscillating electric field, not massive current.
A world class expert as your Oz person does of course know that a current
is defined by transport of charged moieties, and of course a current
generates a magnetic field -- always -- but that magnetic field can be
sometimes considered negligable, because it gets compensated, or is too
small. Such as protons falling down a gradient, or movement of electrons
in a plate driven by an electric potential changing over time.
Electrostatic motors work very well on cm scale (electret multipole,
plates hooked up to a ~kV oscillating potential), and it only gets better
from there down.
> There are some very nice examples of work where part of the ATPase enzyme
> has been attached to a surface and a small silicon bar or polystyrene bead
> is attached to the protein rotor and the rotation of the silicon bar or bead
> is observed if you supply the system with the right cocktail of chemical
> ingredients. I've attached a PowerPoint presentation from a conference last
> year where this work was presented, and it is worth tracking down the
> groups because they give some nice moving graphics for this.
Owls to Athens.
> Scientists like precision in language. 1 micron is 1000 times greater than
How convenient: we, too.
> 1 nanometer, hence perhaps Microtechnology is more appropriate than
> Nanotechnology. Also the NSF and other scientific nanotechnology definitions
Well, I guess a structure of several megameters made from nanoscale
components needs to be called megatechnology. Similiar applies to
kilotechnology, decatechology, centatechnology and millitechnology. So
she's an expert in decatechnology, then, as critters are typically cm
scale.
A great suggestion, I think her promotion to president of the Babel
commitee is imminent.
> relate to both size and also the particular properties which are observed
> for material at that scale which are not observed for larger-scale, i.e.
> micro and upwards, material. Hence when talking about nanobots the word
> implies the nano-scale and hence the arguments against such entities being
> possible at the nano-dimension.
Science is not usually associtated with sophism.
> In conclusion, George does know what he is talking about with regards to
> what our current understanding is of mechanisms and what might or might not
> be possible based on our current knowledge of scientific principles.
Arguments based on authority do sound hollow. There are no experts on
nanotechnology around, it's a huge, brand new field. Making detailed
predictions about what is possible, what is impossible, and what is
sensible at current stage at the game must hence necessarily appear
hubris.
No one knows anything for certain. Claiming you are is good for grants and
ego, but it is not instrumental in the advancement of truth.
-- Eugen* Leitl <a href="http://www.lrz.de/~ui22204/">leitl</a>
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