Power/Performance Bits: Feb. 18

Carbon nanotube fibers created by Rice University researchers outperform copper in electricity transmission; a Penn State researcher relies on quantum simulations to design new materials.


Outperforming copper
Carbon nanotube-based fibers invented at Rice University have greater capacity to carry electrical current than copper cables of the same mass — on a pound-per-pound basis — according to new research.

While individual nanotubes are capable of transmitting nearly 1,000 times more current than copper, the same tubes coalesced into a fiber using other technologies fail long before reaching that capacity. However, Rice researchers said a series of tests showed the wet-spun carbon nanotube fiber still handily beat copper, carrying up to four times as much current as a copper wire of the same mass.

That makes nanotube-based cables an ideal platform for lightweight power transmission in systems where weight is a significant factor, like aerospace applications.

Quantum development
Ismaila Dabo, a computational materials scientist at Penn State creates simulations of everything from electrochemical environments to solar systems — exploring a realm governed by the fuzzy probabilistic rules of quantum mechanics. As scientists and engineers explore the world of the very small and as computers become faster and more powerful, materials researchers are increasingly relying on computer engineers to help them efficiently design new materials.

Before the computer era, materials scientists relied on hunches and guesswork when they devised new types of materials, he said. But now, creating simulations at the quantum level and making predictions on how new materials will behave requires immense computing power, only recently available. Simulations can give researchers a chance to model changes in a material and test its performance without expensive rounds of experimentation. Accurate simulations also shave off considerable time in research and development.

He noted that there is a lot of time between development of materials and deployment — usually about 20 years but by combining computations and experiments, it is hoped that this development time could be decreased by anywhere from five to seven years. Faster development of materials and metamaterials will in turn improve the speed and performance of future computers.

Further, he said, power is crucial. Materials that don’t heat up so much can pave the way for more powerful computers and better batteries can allow people to use their phones and laptops for longer periods without recharging.

Better computers are only one improvement he hopes his efforts will yield. Hydrogen fuel cells, which convert hydrogen fuel into sustainable electricity, are another area of exploration.

Materials improvements may also lead to better capacitors and batteries and pave the way for electric cars and hybrid vehicles that can travel farther on a single charge and recharge much faster once they do run low on power, he added.


Dave says:

So, is it that the nanotubes have lower resistance than the non-nanotube counter parts? Or is it that they can withstand higher temperatures? Wasn’t clear.

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