His mission impossible takes him from core of the sun to center of the Earth

Feb 28, 2017

By UCLA Samueli Newsroom

Jaime Marian creates computer models of extreme conditions that cannot be replicated in a lab

Imagine stepping into your lab to find that you have captured your very own star on which to conduct research. It’s a nice thought, but housing what amounts to an exploding ball of gas that can reach 100,000 degrees Fahrenheit isn’t what most scientists would call practical or what most labs can handle.

Enter Jaime Marian, a UCLA associate professor of materials science and engineering and a member of the executive committee of the Institute of Digital Research and Education, a campuswide cooperative of faculty and technologists who are working to advance computing knowledge and expertise at UCLA.

“We could have all the expensive, experimental equipment available that is out there,” Marian said. “But there are always conditions which we cannot replicate in the lab.”

Like the center of the sun. The depths of the ocean. The pressure of the Earth’s mantle. These are just a few examples of extreme conditions that are impossible to produce in a standard laboratory.

That’s where the Marian Group comes in. Using computational modeling, this research collective that’s based in the UCLA Henry Samueli School of Engineering and Applied Science, formulates theoretical models of how materials will behave under conditions that are nearly impossible to physically replicate, such as ultrafast heating, high-dose irradiation or very fast deformation rates.

Using computational materials science, however, Marian and his lab have helped researchers across the campus simulate such extraordinary conditions. Among the researchers the lab has collaborated with are archaeologists, physicists, researchers in the David Geffen School of Medicine as well as other scientists in the engineering school.

“I want to at least be able to say something about how materials behave in those extreme environments to help guide or complement experimental science,” he said.

One key goal for Marian and his team of postdocs and grad students is to make these models multiscale — that is, linking spatial and temporal scales, from the very small electron level all the way up to the engineering scale.

When you can see material behave or evolve under certain conditions, what you see with your eyes is far from the whole story, Marian explained. Rather, often times what you see has been triggered at the atomistic scale, a scale that operates on an extremely fast and small level. For example, what is happening on a microscopic scale when a laser interacts with ocular tissue during laser eye surgery has consequences on the observable scale in the form of one’s eyesight.

“Things that happen in the length of one nanosecond can have impact on what happens on the scale of minutes or hours,” he said. “We don’t want to neglect that information.” And multiscale modeling gives researchers the “big picture” of how that behavior triggers changes at different scales.

To be able to create conditions using computational modeling takes an understanding of many different scientific processes. “I know everyone uses the word ‘multidisciplinary’ nowadays, but in our case, it is totally appropriate,” Marian said. “One has to have knowledge of quantum mechanics, thermodynamics and kinetics and continuum mechanics to develop our models.”

The two most challenging scenarios Marian and his lab have had to model are materials for fusion energy — “like housing a small star in a metallic chamber” — and subjecting materials to extremely high pressures at the Earth’s core or during explosions.

All this takes considerable computer power. But instead of the lab having to maintain its own computer cluster, Marian works through UCLA’s Institute of Digital Research and Education, which offers a campuswide program to help faculty when their research requires computational thinking, using high performance computation, data visualization and data analysis of large data sets and databases.

“Instead of everyone having their own little dispersed [computer] cluster and me having to worry about maintenance and upkeep, everything was centralized through IDRE,” he said. “One of the defining factors for which I chose UCLA over some other opportunities was the existence of IDRE.”

Since his arrival at UCLA three years ago, Marian has managed to keep more than busy. In addition to being personally involved in the research of each of seven postdoctoral researchers and students involved in his group, he is currently working on multiple projects of his own.

One involves simulating the processes happening at the atomistic scale that lead to the corrosion of materials, while another deals with the development of materials that are able to withstand the energy of fusion, or the process which powers the sun and stars.

Marian may not be working with actual stars when he models their function under laboratory conditions, but he’s reaching for them nonetheless.

By Nico Correia
Featured image: A computational model shows the formation of bubbles in metals under extreme pressures. While these conditions are difficult to produce in a lab, the Marian Group can model these conditions for researchers’ experiments.
Credit: UCLA

This story was adapted from one running on the Institute of Digital Research and Education website. To see more simulations, go to the Marian Group’s website.


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