Nanotecnólogos precisam ter lições da natureza

quarta-feira, junho 08, 2011

Nanotechnologists Must Take Lessons from Nature

ScienceDaily (June 6, 2011) — It's common knowledge that the perfect is the enemy of the good, but in the nanoscale world, perfection can act as the enemy of the best.

The simple E. coli bacterium shown can compute 1,000 times faster than the most powerful computer chip, its memory density is 100 million times higher and it needs 100 millionth the power to operate. (Credit: Jenni Ohnstad/Vanderbilt University)

In the workaday world, engineers and scientists go to great lengths to make the devices we use as perfect as possible. When we flip on a light switch or turn the key on the car, we expect the lights to come on and the engine to start every time, with only rare exceptions. They have done so by using a top-down design process combined with the application of large amounts of energy to increase reliability by suppressing natural variability.

However, this brute-force approach will not work in the nanoscale world that scientists are beginning to probe in the search for new electrical and mechanical devices. That is because objects at this scale behave in a fundamentally different fashion than larger-scale objects, argue Peter Cummings, John R. Hall Professor Chemical Engineering at Vanderbilt University, and Michael Simpson, professor of materials science and engineering at University of Tennessee, Knoxville, in an article in the April issue of the ACS Nano journal.

'Noise' makes a difference

The defining difference between the behaviors of large-scale and nanoscale objects is the role that "noise" plays. To scientists noise isn't limited to unpleasant sounds; it is any kind of random disturbance. At the level of atoms and molecules, noise can take the form of random motion, which dominates to such an extent that it is extremely difficult to make reliable devices.

Nature, however, has managed to figure out how to put these fluctuations to work, allowing living organisms to operate reliably and far more efficiently than comparable human-made devices. It has done so by exploiting the contrarian behavior that random behavior allows.

Read more here/Leia mais aqui: Science Daily 


Journal reference/Referência da publicação científica:

Michael L. Simpson, Peter T. Cummings. 

Fluctuations and Correlations in Physical and Biological Nanosystems: The Tale Is in the Tails. 

ACS Nano, 2011; : 110401122441089 DOI: 10.1021/nn201011m


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