I recently told Vlad Sokhan, a Strategic Research Fellow in molecular modelling at NPL about Amazon’s amazing new hardware-on-demand service, called Elastic Compute Cloud (EC2), that I’d heard about from Jeff Barr’s speech at a recent conference in Brighton (I listened to the podcast as the conference was full!). Vlad needs computing power for his molecular modelling work and currently uses the NPL grid.
He showed me a short movie segment that had taken over 30 hours of PC time to render. The movie showed methane molecules flowing through a carbon nanotube and had led Vlad to discover a kind of super-flow, which was 100 times faster than expected.
In view of these and other amazing properties carbon nanotubes are expected to underpin future developments such as new energy sources and miniature chemical factories that could help remove greenhouse gases from power station emissions.
Within the space of an evening Troy McLuhan and I had finished an exhibit of a 3D carbon nanotube and the movie with an explanatory information card. It took rather longer to decide where to place it at the new Science Center on Info Island. Here’s a picture of the final exhibit which was there for the Science Center opening meeting on October 12th.
Here comes the science: Carbon nanotubes continue to amaze scientists with their unique and unusual properties. How does the super-flow work you ask. Well, traditional models of fluid flow do not work well with nanotubes since they either use a fixed volume of fluid containing a changing population of particles or a continuous flow that is slower near the edges. Vlad’s approach accurately models the molecules behaviour as they encounter the inside surface of the nanotube. For a variety of reasons they actually speed up and travel further and faster along the tube walls than previously thought, and spend longer close to the walls instead of bouncing back into the main flow.
Further reading: There is a readable description of the possible use of nanotubes as highly efficient membranes for separating carbon dioxide from power plant flue gases in this article:
Science 19 May 2006: Vol. 312. no. 5776, pp. 1003 – 1004
Making High-Flux Membranes with Carbon Nanotubes
David S. Sholl and J. Karl Johnson
For the more technical readers, here is Vlad Sokhan’s original work:
Journal of Chemical Physics Volume 117, Number 18 8 November 2002
Fluid flow in nanopores: Accurate boundary conditions for carbon nanotubes
Vladimir P. Sokhan, David Nicholson, and Nicholas Quirkea
And a recent Nature paper where this finding was experimentally verified:
Nature 438, 44 (3 November 2005)
Nanoscale hydrodynamics: Enhanced flow in carbon nanotubes
Mainak Majumder, Nitin Chopra, Rodney Andrews and Bruce J. Hinds
Visit the exhibit (requires Secondlife client).