NanoEngineer - MarkIII(k) Planetary Gears

This is the MarkIII(k), a planetary gear created by K. Eric Drexler. A planetary gear couples an input shaft via a sun gear to an output shaft through a set of planet gears (attached to the output shaft by a planet carrier). The planet gears roll between the sun gear and a ring gear on the inner surface of a casing. The animation below was produced from a NanoEngineer-1 molecular dynamics simulation. A section of the casing atoms have been hidden to expose the internal gearing assembly.

Planetary gears are attractive targets for molecular modeling because (with careful choice of planet numbers and sun- and ring-gear symmetries) the overall symmetry of the system virtually guarantees low energy barriers along the desired motion coordinate. They also pack considerable complexity into a small structure.

Planetary gears are common mechanical systems used for speed reduction (= torque multiplication). Macroscale versions are found in automobile transmissions, electric screwdrivers, and Mars landers.

The MarkIII(k) gear updates an early 1990s design by Drexler and Merkle, modified to reduce interactions between the sun gear and the bases of the planet gears. The original version was designed with very small moving parts in order to fit the computational constraints of the time. The planet gears are near the lower limits of diameter for functional gear components, and because of this, the "gear teeth" in this system are better thought of as smooth, low-amplitude corrugations in the gear surfaces.

The single covalent (sigma) bonds linking each of the nine planet gears to the carrier gear are easily seen in this POV-Ray image.

This information is collected from the bellow website
http://www.nanoengineer-1.com/content/

Uses of Carbon Nanotubes

Low-friction Carbon Nanotube Bearing Assembly

The high tensile strengths and stiffness of carbon nanotubes have made them important as building materials in many current nanoscience applications. Their range of use is expected to extend to molecular manufacturing applications in nanoscale scaffolding and molecular electronics. Their cylindrical shape and highly delocalized electronic structure make them interesting possible choices for the design of molecular bearing assemblies. In the design at left, the cut-away section is a single covalent structure, around which a low-friction diamondoid bearing is kept from finding a highly stable minimum energy position.

Author:Damian G. Allis
Department of Chemistry, Syracuse University

A Carbon Nanotube Molecular Bearing Assembly

The design of complex nanosystems with numerous moving parts is made complicated by the fundamental limits of chemical bonding and the possible interfaces between moving parts that can be achieved with certain nanostructures. It is possible that this spatial quantization of atomically precise building materials may also be used to drive the self-assembly of some nanosystems, greatly simplifying the assembly process. The nesting of appropriately sized carbon nanotubes, such as shown at left, can serve as a strong driving force for molecular bearing self-assembly.

Author:Damian G. Allis

Department of Chemistry, Syracuse University


Carbon Nanotube Crimp Junction


The high tensile strengths of carbon nanotubes make them likely material candidates in future nanoscale manufacturing applications. In the absence of atomically precise manufacturing methods for fabricating continuous scaffoldings of a single nanotube, methods that lock nanotubes into place by strong electrostatic and/or steric approaches may be possible. The diamondoid crimp junction shown at left is a single covalent nanostructure that fixes two nanotubes at right angles.

Author: Damian G. Allis
Department of Chemistry, Syracuse University


Carbon Nanotube 6-way Junction

The junction at left is generated by three pairs of carbon nanotubes fixed along (x,y,z) axes. The interfaces at the center of this junction are composed of 6 adamantane molecules covalently bound to each carbon nanutobe and functionalized with either nitrogen (N) or boron (B) atoms. These nanotubes are not covalently bound to one another, instead employing dative bonding between nearest-neighbor B-N pairs to hold the six nanotubes in place, a method that offers the possibility of complex structure formation via familiar chemical self-assembly.

Author: Damian G. Allis
Department of Chemistry, Syracuse University