Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Scientists use world’s fastest computer to simulate nanoscale material failure

Abstract:
How nanowires evolve under stress is simulated atom-by-atom over a period of time that is closer than ever to experimental reality

Scientists use world’s fastest computer to simulate nanoscale material failure

Los Alamos, NM | Posted on October 29th, 2009

Very tiny wires, called nanowires, made from such metals as silver and gold, may play a crucial role as electrical or mechanical switches in the development of future-generation ultrasmall nanodevices.

Making nanodevices work will require a deep understanding of how these and other nanostructures can be engineered and fabricated as well as their resultant strengths and weaknesses. How mechanical properties change at the nanoscale is of fundamental interest and may have implications for a variety of nanostructures and nanodevices.

A major limiting factor to this understanding has been that experiments to test how nanowires deform are many times slower than computer simulations can go, resulting in more uncertainty in the simulation predictions than scientists would like.

"Molecular dynamics simulations have been around for a long time," said Arthur Voter of the Theoretical Division at Los Alamos National Laboratory. "But the simulations have never before been able to mimic the atomistic tensile strength of nanowires at time scales that even come close to experimental reality."

Using the "parallel-replica dynamics" method for reaching long time scales that Voter developed, members of Voter's team adapted their computer code to exploit the Roadrunner supercomputer's hybrid architecture, allowing them to perform the first-ever simulation of a stretching silver nanowire over a period of a millisecond, or one-thousandth of a second, a time that approaches what can be tested experimentally.

"Bigger supercomputers have made it possible to perform simulations on larger and larger systems, but they have not helped much with reaching longer times -- the best we can do is still about a millionth of a second. However, with the parallel-replica algorithm, we can utilize the large number of processors to ‘parallelize' time," said Voter. "Roadrunner is ideally suited to this algorithm, so now we can do simulations thousands of times longer than this."

With this new tool, scientists can better study what nanowires do under stress. "At longer time scales we see interesting effects. When the wires are stretched more slowly, their behavior changes -- the deformation and failure mechanisms are very different than what we've seen at shorter time scales," said Voter.

Through these simulations, Voter and his team are developing a better understanding of how materials behave when they are reduced to the size scale of a nanometer, or one-billionth of a meter. "At this scale, the motion of just one single atom can change the material's mechanical or electrical properties," said Voter, "so it is really helpful to have a tool that can give us full atomic resolution on realistic time scales, almost as if we are watching every atom as the experiment proceeds."

Voter's team includes Danny Perez and postdoc Chun-Wei Pao of Physics and Chemistry of Materials, and Sriram Swaminarayan of Computational Physics and Methods.

####

About Los Alamos National Laboratory
Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and the Washington Division of URS for the Department of Energy’s National Nuclear

Security Administration

Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.

About Roadrunner, the world’s fastest supercomputer, first to break the petaflop barrier

On Memorial Day, May 26, 2008, the “Roadrunner” supercomputer exceeded a sustained speed of 1 petaflop/s, or 1 million billion calculations per second. “Petaflop/s” is computer jargon—peta signifying the number 1 followed by 15 zeros (sometimes called a quadrillion) and flop/s meaning “floating point operation per second.” Shortly after that it was named the world’s fastest supercomputer by the TOP500 organization at the June 2008 International Supercomputing Conference in Dresden Germany.

The Roadrunner supercomputer, developed by IBM in partnership with the Laboratory and the National Nuclear Security Administration, will be used to perform advanced physics and predictive simulations in a classified mode to assure the safety, security, and reliability of the U.S. nuclear deterrent. The system will be used by scientists at the NNSA’s Los Alamos, Sandia, and Lawrence Livermore national laboratories.

The secret to its record-breaking performance is a unique hybrid design. Each compute node in this cluster consists of two AMD Opteron™ dual-core processors plus four PowerXCell 8i™ processors used as computational accelerators. The accelerators used in Roadrunner are a special IBM-developed variant of the Cell processor used in the Sony PlayStation 3®. The node-attached Cell accelerators are what make Roadrunner different than typical clusters.

Roadrunner is still currently the world's fastest with a speed of 1.105 petaflop/s per second, according to the TOP500 announcement at the November 2008 Supercomputing Conference in Austin Texas, and it again retained the #1 position at the June ISC09 conference

For more information, please click here

Contacts:
Kevin N. Roark
505-665-9202

Copyright © Los Alamos National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Scientists join forces to reveal the mass and shape of single molecules April 27th, 2015

The 16th Trends in Nanotechnology International Conference (TNT 2015) unveils 25 Keynote Speakers: Call for abstracts open April 27th, 2015

Graphenea celebrates fifth anniversary April 27th, 2015

Sensor Designed in Iran Able to Remove Formaldehyde Gas from Environment April 27th, 2015

Possible Futures

Printing Silicon on Paper, with Lasers April 21st, 2015

A glass fiber that brings light to a standstill: By coupling photons to atoms, light in a glass fiber can be slowed down to the speed of an express train; for a short while it can even be brought to a complete stop April 9th, 2015

Nanotechnology in Medical Devices Market is expected to reach $8.5 Billion by 2019 March 25th, 2015

Nanotechnology Enabled Drug Delivery to Influence Future Diagnosis and Treatments of Diseases March 21st, 2015

Molecular Machines

UCLA nanoscientists are first to model atomic structures of three bacterial nanomachines: Cryo electron microscope enables scientists to explore the frontiers of targeted antibiotics April 21st, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Designer's toolkit for dynamic DNA nanomachines: Arm-waving nanorobot signals new flexibility in DNA origami March 27th, 2015

Tiny bio-robot is a germ suited-up with graphene quantum dots March 24th, 2015

Announcements

Scientists join forces to reveal the mass and shape of single molecules April 27th, 2015

The 16th Trends in Nanotechnology International Conference (TNT 2015) unveils 25 Keynote Speakers: Call for abstracts open April 27th, 2015

Graphenea celebrates fifth anniversary April 27th, 2015

Sensor Designed in Iran Able to Remove Formaldehyde Gas from Environment April 27th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project