Friction in gem-gum technology
In gemstone based nanomachinery one usually wants the operation frequencies to be well below the thermal motion frequencies. Otherwise the mechanical motions couple too strongly into thermal motions and things will get very hot very quickly. The frequencies of thermal motions can be seen in oscillation infrared spectra. Typical covalent bonds are located in the wavelength range of 3µm-30µm. This corresponds to 10THz-0.1PHz.
Contents
Less soft nanomachines => less drag
Unlike compliant bio-molecules in water stiff structures like carbon nanotubes (or bearings out of gemstone) in dry vacuum do not provide low energy low frequency rotative degrees of freedom (DOFs) to couple into. Those DOFs could (if they where present like in water) go down all the way to the microwave range: ~ 3cm & 10GHz. So overlap of mechanical motion with rotative thermal motion isn't so much of a problem even at higher operation frequencies.
Note that existing simulations of crystolecules can show a a stroboscopic effect. That can lead one to believe machine motion and thermal motion lie very close together and that consequently friction would be horrendous. This is not the case. It's just an artifact of the simulation.
Typical operation frequencies
Tis is strongly depending on the method of bearing (superlubrication / single sp3 bonds as bearings / some for m of levitation / ... ) and efficiency of operations.
- For mechanosynthetic mills in a nanofactory where larger forces are present and potentially slightly inefficient mechanosynthesis is performed the low MHz range is a good target.
- For low friction bearings (like in nanomechanical computing) one can go up into the high MHz to low GHz range. This still leaves a gap of three orders of magnitude to the oszillative thermal motion DOFs.
Related
External links
- (TODO: Add ref's to relevant chapters in "Nanosystems")
- Wikipedia: Rotational spectroscopy
- Wikipedia: Rotational–vibrational spectroscopy
- Wikipedia: Thermal infrared spectroscopy
