Michela Geri: Developing Particulate Systems for Environmental and Sustainability Endeavors

Michela Geri will join the faculty of Duke University’s Department of Mechanical Engineering and Materials Science, beginning January 1, 2024. With expertise in modeling and understanding the behavior of materials that combine liquids with an intrinsic solid component, Geri adds to a growing group focused on capturing, storing and transporting gasses for energy and sustainability purposes.

Currently a postdoctoral associate at the Massachusetts Institute of Technology (MIT), Geri earned her bachelor’s and master’s degrees in energy engineering at the University of Bologna in Italy. She later moved to the US to pursue her PhD in mechanical engineering at MIT, where she also spent a few years teaching.

Both as a doctoral student and in her current role, Geri has focused on a variety of multi-phase materials, ranging from particle/droplet suspensions to solids solutions. She is particularly interested in structured fluids—essentially materials where a solid phase coexists with a fluid phase. Such substances are found all around us, from natural suspensions like milk or coffee to engineered materials to deliver pharmaceuticals or store and transport energy.

“My focus in this area of materials science is specifically on energy and environmental issues,” Geri said. “These types of materials are complicated because studying only the fluid or solid alone won’t give you a complete picture of them. You have to build up different aspects of fluid dynamics and rheology to materials science to gain an extensive understanding.”

Geri is particularly interested in gas hydrates—crystalline solids formed of water and gas that look just like ice from the outside but are extremely porous on the atomic scale. With an incredible amount of tiny nooks and crannies for molecules to fit into, 160 cubic meters of a gas such as methane can fit into a single cubic meter of hydrate.

This ability could be a boon for energy and sustainability efforts. For example, such hydrates could be used to store hydrogen and transport it across long distances, as elemental hydrogen causes metals typically used in pipe construction to break down and fracture over time. They could also be used to capture and store carbon dioxide from sources of pollution or the atmosphere.

But hydrates have a dark side as well. Because they can form naturally within complex liquids, they’re a large cause for concern to the oil industry. If left undiscovered and unchecked, hydrates can clog pipes or even cause explosions—as they did in the Deepwater Horizon in the Gulf of Mexico in 2010.

“Gaining a deeper understanding of how hydrate-rich fluids and other multi-phase materials behave is difficult, however, because our standard protocols and experimental setups aren’t fast enough to track mechanical and thermodynamic changes as they evolve in real time,” Geri said. “Another aspect of my research is developing techniques for tracking ‘fingerprints’ of how these materials change 100 times faster than conventional methods.”

According to Geri, a lot can be achieved by carefully designing the test signals employed. The devices built to take these measurements were originally developed to test simple materials that do not change fast over time, so there wasn’t a need to gather the data quickly. Now that the field has spread to more complex and dynamic materials, researchers must develop ways for sampling the results faster.

It’s sort of like learning children’s melodies versus classical symphonies. You can pick up “Twinkle Twinkle Little Star” even if the track is skipping a lot. But you’re going to miss a lot of notes in “Flight of the Bumblebee” if the playback isn’t continuous.

Combining skillsets in mechanical engineering, fluid dynamics, sustainability, modeling, signal processing and energy requires talented and interdisciplinary teams. But it also helps if the individual researchers themselves have expertise in a wide range of disciplines. Seeing that characteristic in her new colleagues at Duke Engineering, Geri said, is a big reason why she decided to accept the offer for her new position.

“If we want to tackle complex problems facing climate change and sustainability, we can’t just work in our own fields looking straight ahead, we have to look more widely,” Geri said. “You can do that through collaboration, but if you can do it within yourself and within your own group, that makes a huge difference. I discovered that at Duke, that’s not only possible, but it’s encouraged. I found that approach quite unique and I love that about Duke.”

Geri said she was also attracted to Duke Engineering’s commitment to teaching and mentorship. Having spent a few years teaching before starting her postdoctoral appointment, helping prepare the next generation of future engineering leaders is one of her favorite aspects of the job. At Duke, she plans on developing some new courses for both graduates and undergraduates, while also helping to expand a few existing courses to feature more hands-on experiences in materials science. She’s especially fond of teaching the mechanics of materials, because it’s often the first class that exposes students to core concepts of mechanical engineering and materials science.

Outside of the laboratory and classroom, Geri said she’s also looking forward to moving to Duke to explore the natural beauty of North Carolina from the mountains to the oceanfront. “Durham looks like a foodie place, too,” Geri added. “Most Italians get excited about cooking and food, and I can’t wait to explore the local cuisine and atmosphere.”