Featured Research

from universities, journals, and other organizations

'Prettier World' Of Computer Modeling Provides Key Details

Date:
June 13, 2006
Source:
Sandia National Laboratories
Summary:
Nanotechnology simulations show what experiments miss. Taking issue with the perception that computer models lack realism, Sandia National Laboratories researcher Eliot Fang told members of the Materials Research Society that simulations of the nanoscale provide researchers more detailed results - not less - than experiments alone.

Rendering of Sandia simulations by Michael Chandross demonstrates significant transfer of material to the probe tip of an atomic force microscope.
Credit: Image courtesy of Sandia National Laboratories

Taking issue with the perception that computer models lack realism, a Sandia National Laboratories researcher told his audience that simulations of the nanoscale provide researchers more detailed results — not less — than experiments alone.

The invited talk by Eliot Fang was delivered to members of the Materials Research Society at its recent semiannual general meeting.

Sandia is a National Nuclear Security Administration laboratory.

Fang derided the pejorative “garbage in, garbage out” description of computer modeling — the belief that inputs for computer simulations are so generic that outcomes fail to generate the unexpected details found only by actual experiment.

Fang not only denied this truism but reversed it. “There’s another, prettier world beyond what the SEM [scanning electron microscope] shows, and it’s called simulation,” he told his audience. “When you look through a microscope, you don’t see some things that modeling and simulation show.”

This change in the position of simulations in science — from weak sister to an ace card — is a natural outcome of improvements in computing, Fang says. “Fifteen years ago, the Cray YMP [supercomputer] was the crown jewel; it’s now equivalent to a PDA we have in our pocket.”

No one denies that experiments are as important as simulations — “equal partners, in fact,” says Julia Phillips, director of Sandia’s Physical, Chemical, and Nanosciences Center.

But the Labs’ current abilities to run simulations with thousands, millions, and even billions of atoms have led to insights that would otherwise not have occurred, Fang says.

For example, one simulation demonstrated that a tiny but significant amount of material had transferred onto the tip of an atomic force microscope (AFM) as it examined the surface of a microsystem.

“The probe tip changed something very, very tiny on the surface of the material,” says Fang. “It was almost not noticeable. But the property of the surface became very different.”

Laboratory observation couldn’t identify the cause of the property change, but computer simulations provided a reasonable explanation of the results.

As for predicting the reliability of materials that coat surfaces, Fang says, “We find that when we compare our simulation models with data from the experiments, we get a more complete understanding.”

Says Sandia Fellow and materials researcher Jeff Brinker, “We use simulations quite a bit in support of Sandia’s water purification program and the NIH Nano-Medicine Center program. In all these cases I’m working with theorists and modelers to guide the design of synthetic nanopores so as to develop transport behaviors approaching those of natural water or ion channels that exist in cell membranes.”

How is this understanding achieved?

Models computationally link a variety of size and time scales to create an experimental design.

“We use as much experimental information as possible to validate our methods,” says Alex Slepoy from Sandia’s Multiscale Computational Materials Methods. “The trick is picking a correct modeling strategy from our toolbox of methods.”

Asked whether simulations are merely more complex versions of what a graphic artist produces — a product of the imagination, in short, that cannot accurately produce new details — Slepoy provisionally entertains the idea: “A graphic artist has to make choices that are somewhat subconscious: what size objects to represent, how close-in to zoom, what details to include and exclude, and are there people out there who liked what he drew. So do we.

“But there the similarity ends. For us in computer simulations, the questions are more technical: Does the modeling strategy agree with experiments and is it consistent with established models? Does it have mathematical consistency?”

A further advance in accurate model development, he says, is that “now we’re developing automated methods to tell us whether we’ve satisfied [accuracy] requirements, rather than doing that by just manually looking at results. The method automatically tunes the model to satisfy the entire set of conditions as we know them.”

There is also the matter of cost, says Fang: “With smart people developing numerical methods, models, and algorithms to use computers to study real cases, we find we can rerun calculations merely by changing computer parameters. Thus the cost to push science forward is much cheaper than running experiments — particularly in nanoscience, where the realm is so small that experiments are difficult to perform, testing devices are not available, and data acquisition is a challenge.”

For all these reasons, he says, “This is why at CINT [the Sandia/Los Alamos Center for Integrated Nanotechnology, funded by DOE’s Office of Science], theory and simulation is one of its five thrusts. People view modeling and simulation as a critical component of nanoscience.”

“We need to sit back and put our mindset in a different mode,” he told his audience. “We’re all too busy doing [laboratory] research [instead of considering] how we can leverage resources to push our science to the next level.”

Modeling tools include: meso-scale (an intermediate resolution capability functioning between the atomic and macro scales), classical atomistics (classical force-field theory), Density Functional Theory (a one-electron approximation of quantum theory, where an electron interacts with atoms but not with another electron), and the full quantum model (electrons interacting with other electrons and four or five ions).


Story Source:

The above story is based on materials provided by Sandia National Laboratories. Note: Materials may be edited for content and length.


Cite This Page:

Sandia National Laboratories. "'Prettier World' Of Computer Modeling Provides Key Details." ScienceDaily. ScienceDaily, 13 June 2006. <www.sciencedaily.com/releases/2006/06/060613080755.htm>.
Sandia National Laboratories. (2006, June 13). 'Prettier World' Of Computer Modeling Provides Key Details. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2006/06/060613080755.htm
Sandia National Laboratories. "'Prettier World' Of Computer Modeling Provides Key Details." ScienceDaily. www.sciencedaily.com/releases/2006/06/060613080755.htm (accessed October 22, 2014).

Share This



More Computers & Math News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) — If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) — Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) — Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins