Featured Research

from universities, journals, and other organizations

Outside a vacuum: Model predicts movement of charged particles in complex media

Date:
November 28, 2012
Source:
Northwestern University
Summary:
It's a problem that has stumped scientists for years. Now researchers have developed a model that can predict the movements of charged particles, even in heterogeneous environments like cells, blood, or colloids.

Picture two charged particles in a vacuum. Thanks to laws of elementary electrostatics, we can easily calculate the force these particles exert upon one another, and therefore predict their movements.

Related Articles


Submerge those particles in a simple medium -- say, water -- and the calculation grows more complex. The charged particles' movements influence the water, which in turn may slow, speed, or otherwise alter the particles' paths. In this environment a prediction must also consider the water's reaction, or its dielectric response.

But in real biological and material systems, media are also complex: plant cells and blood cells, for instance, are made up of several media and may be oddly shaped. This heterogeneity has made predicting the movement of charged particles in complex environments extremely challenging for theoretical physicists.

Now researchers at Northwestern University's McCormick School of Engineering have developed a model that can predict the reactions of charged particles in any media. Their computational discovery, which takes cues from nature, could find applications in biology, medicine, and synthetic materials research.

The model is the culmination of seven years of work by Monica Olvera de la Cruz, Lawyer Taylor Professor of Materials Science and Engineering, Chemistry, and (by courtesy) Chemical and Biological Engineering at the McCormick School of Engineering, with partners from Arizona State University.

Creating molecular simulations in heterogeneous media requires two steps: measuring the effects of the medium's dielectric response on the charged particles and measuring the effects of the charged particles on the medium's dielectric response. In previous attempts at such simulations, models treated the two calculations separately, completing one set of calculations before turning to the next. This process required solving a differential equation that governs the motion of the charged particles -- namely, the Poisson equation -- at each step of the simulation.

The Northwestern researchers have developed a new, faster way that avoids the Poisson equation entirely. Using insight gleamed from nature, they have reframed the electrostatic problem as an energy-minimizing problem.

"Nature doesn't wait to figure out the response of the medium in order to move the charged particles, nor does it wait to position the particles before determining the response of the medium," said Olvera de la Cruz. "The dielectric response and the motion of the charged particles are inherently coupled, and our model mirrors that."

The researchers formulated a new function that gives the correct response of the medium and produces the true energy of the charged particles. This enabled them to update the position of the charged particles and the medium's response in the same simulation time step. Within this theoretical framework and simulation design, they were able to attack problems that were previously intractable.


Story Source:

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


Journal Reference:

  1. Vikram Jadhao, Francisco Solis, Monica de la Cruz. Simulation of Charged Systems in Heterogeneous Dielectric Media via a True Energy Functional. Physical Review Letters, 2012; 109 (22) DOI: 10.1103/PhysRevLett.109.223905

Cite This Page:

Northwestern University. "Outside a vacuum: Model predicts movement of charged particles in complex media." ScienceDaily. ScienceDaily, 28 November 2012. <www.sciencedaily.com/releases/2012/11/121128112155.htm>.
Northwestern University. (2012, November 28). Outside a vacuum: Model predicts movement of charged particles in complex media. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2012/11/121128112155.htm
Northwestern University. "Outside a vacuum: Model predicts movement of charged particles in complex media." ScienceDaily. www.sciencedaily.com/releases/2012/11/121128112155.htm (accessed October 24, 2014).

Share This



More Computers & Math News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) — Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Microsoft Riding High On Strong Surface, Cloud Performance

Microsoft Riding High On Strong Surface, Cloud Performance

Newsy (Oct. 24, 2014) — Microsoft's Q3 earnings showed its tablets and cloud services are really hitting their stride. Video provided by Newsy
Powered by NewsLook.com
The Best Apps to Organize Your Life

The Best Apps to Organize Your Life

Buzz60 (Oct. 23, 2014) — Need help organizing your bills, schedules and other things? Ko Im (@konakafe) has the best apps to help you stay on top of it all! Video provided by Buzz60
Powered by NewsLook.com
Nike And Apple Team Up To Create Wearable ... Something

Nike And Apple Team Up To Create Wearable ... Something

Newsy (Oct. 23, 2014) — For those looking for wearable tech that's significantly less nerdy than Google Glass, Nike CEO Mark Parker says don't worry, It's on the way. Video provided by Newsy
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