Energy is everywhere, affecting everything, all the time. And it can be manipulated and converted into the kind of energy that we depend on as a civilization. But transforming this ambient energy (the result of gyrating atoms and molecules) into something we can plug into and use when we need it requires specific materials.

These energy materials — some natural, some manufactured, some a combination — facilitate the conversion or transmission of energy. They also play an essential role in how we store energy, how we reduce power consumption, and how we develop cleaner, efficient energy solutions.

“Advanced materials and clean energy technologies are tightly connected, and at Georgia Tech we’ve been making major investments in people and facilities in batteries, solar energy, and hydrogen, for several decades,” said Tim Lieuwen, the David S. Lewis Jr. Chair and professor of aerospace engineering, and executive director of Georgia Tech’s Strategic Energy Institute (SEI).

That research synergy is the underpinning of Georgia Tech Energy Materials Day (March 27), a gathering of people from academia, government, and industry, co-hosted by SEI, the Institute for Materials (IMat), and the Georgia Tech Advanced Battery Center. This event aims to build on the momentum created by Georgia Tech Battery Day, held in March 2023, which drew more than 230 energy researchers and industry representatives.

“We thought it would be a good idea to expand on the Battery Day idea and showcase a wide range of research and expertise in other areas, such as solar energy and clean fuels, in addition to what we’re doing in batteries and energy storage,” said Matt McDowell, associate professor in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering (MSE), and co-director, with Gleb Yushin, of the Advanced Battery Center.

Energy Materials Day will bring together experts from academia, government, and industry to discuss and accelerate research in three key areas: battery materials and technologies, photovoltaics and the grid, and materials for carbon-neutral fuel production, “all of which are crucial for driving the clean energy transition,” noted Eric Vogel, executive director of IMat and the Hightower Professor of Materials Science and Engineering.

“Georgia Tech is leading the charge in research in these three areas,” he said. “And we’re excited to unite so many experts to spark the important discussions that will help us advance our nation’s path to net-zero emissions.”

Building an Energy Hub

Energy Materials Day is part of an ongoing, long-range effort to position Georgia Tech, and Georgia, as a go-to location for modern energy companies. So far, the message seems to be landing. Georgia has had more than $28 billion invested or announced in electric vehicle-related projects since 2020. And Georgia Tech was recently ranked by U.S. News & World Report as the top public university for energy research.

Georgia has become a major player in solar energy, also, with the announcement last year of a $2.5 billion plant being developed by Korean solar company Hanwha Qcells, taking advantage of President Biden’s climate policies. Qcells’ global chief technology officer, Danielle Merfeld, a member of SEI’s External Advisory Board, will be the keynote speaker for Energy Materials Day.

“Growing these industry relationships, building trust through collaborations with industry — these have been strong motivations in our efforts to create a hub here in Atlanta,” said Yushin, professor in MSE and co-founder of Sila Nanotechnologies, a battery materials startup valued at more than $3 billion.

McDowell and Yushin are leading the battery initiative for Energy Materials Day and they’ll be among 12 experts making presentations on battery materials and technologies, including six from Georgia Tech and four from industry. In addition to the formal sessions and presentations, there will also be an opportunity for networking.

“I think Georgia Tech has a responsibility to help grow a manufacturing ecosystem,” McDowell said. “We have the research and educational experience and expertise that companies need, and we’re working to coordinate our efforts with industry.”

Marta Hatzell, associate professor of mechanical engineering and chemical and biomolecular engineering, is leading the carbon-neutral fuel production portion of the event, while Juan-Pablo Correa-Baena, assistant professor in MSE, is leading the photovoltaics initiative.

They’ll be joined by a host of experts from Georgia Tech and institutes across the country, “some of the top thought leaders in their fields,” said Correa-Baena, whose lab has spent years optimizing a semiconductor material for solar energy conversion.

“Over the past decade, we have been working to achieve high efficiencies in solar panels based on a new, low-cost material called halide perovskites,” he said. His lab recently discovered how to prevent the chemical interactions that can degrade it. “It’s kind of a miracle material, and we want to increase its lifespan, make it more robust and commercially relevant.”

While Correa-Baena is working to revolutionize solar energy, Hatzell’s lab is designing materials to clean up the manufacturing of clean fuels.

“We’re interested in decarbonizing the industrial sector, through the production of carbon-neutral fuels,” said Hatzell, whose lab is designing new materials to make clean ammonia and hydrogen, both of which have the potential to play a major role in a carbon-free fuel system, without using fossil fuels as the feedstock. “We’re also working on a collaborative project focusing on assessing the economics of clean ammonia on a larger, global scale.”

The hope for Energy Materials Day is that other collaborations will be fostered as industry’s needs and the research enterprise collide in one place — Georgia Tech’s Exhibition Hall — over one day. The event is part of what Yushin called “the snowball effect.”

“You attract a new company to the region, and then another,” he said. “If we want to boost domestic production and supply chains, we must roll like a snowball gathering momentum. Education is a significant part of that effect. To build this new technology and new facilities for a new industry, you need trained, talented engineers. And we’ve got plenty of those. Georgia Tech can become the single point of contact, helping companies solve the technical challenges in a new age of clean energy.”

Four researchers from the Georgia Institute of Technology — Alex Blumenthal, Juan-Pablo Correa-Baena, Chunhui Du, and Daniel Genkin — have received 2024 Sloan Research Fellowships, one of the highest honors for early-career faculty.

They are among the 126 researchers chosen from more than 1,000 nominations this year.  Fellows receive $75,000 over two years to advance their research.

"Sloan Research Fellowships are extraordinarily competitive awards involving the nominations of the most inventive and impactful early-career scientists across the U.S. and Canada,” said Adam F. Falk, president of the Alfred P. Sloan Foundation, which has awarded the fellowships since 1955.

Since then, 55 individuals from Georgia Tech have won fellowships, and it has become one of the most prestigious awards for young investigators and a predictor of future research success. For example, 57 Sloan Fellows have received a Nobel Prize and 71 have won the National Medal of Science.

Falk added, “We look forward to seeing how fellows take leading roles shaping the research agenda within their respective fields.”

Complete coverage of Georgia Tech’s Sloan Research Fellows:

• Correa-Baena Tapped for Sloan Fellowship

• College of Sciences faculty Blumenthal, Du Awarded Sloan Research Fellowships

• Cyber-Security Expert Genkin Earns Prestigious Research Fellowship

The United States may be in for a significant wave of evictions in a year or so, the unintended consequence of work to trim Medicaid rolls expanded during the Covid-19 public health emergency, according to new research from Georgia Tech’s School of Public Policy.

The study, led authored by Assistant Professor Ashley C. Bradford and recently published in Health Affairs, found that evictions in Tennessee rose 24.5 percent between 2005 and 2009 relative to other Southern states following the state’s 2005 decision to remove approximately 190,000 people from its Medicaid rolls.

More than 16.4 million people nationwide — 86 times the Tennessee figure from 2005 — have already been taken off Medicaid as states react to a federal law requiring them to return to normal operations after years of expanded eligibility meant to blunt the impact of the pandemic, according to KFF Health News. As many as 24 million people could eventually lose access to Medicaid, according to the outlet.

However, Bradford warns that many aspects of health care administration and the housing market have changed since 2005, so it’s hard to say whether that 24.5% figure in her paper will cleanly translate to the economic and policy environment of 2025. The populations involved in Tennessee’s downsizing and the current national rollbacks are also different, adding more uncertainty.

“I think it’s safe to say that we will see disruptions in housing, but we are not going to be able to see exactly how large those disruptions will be for a few years,” Bradford said.

Transformed Health Care and Housing Landscapes May Shift Impact

Among other things, where Tennessee’s 2005 Medicaid changes primarily affected working-age childless adults, the researchers say that the current Medicaid rollback is expected to disproportionately affect immigrants and people with disabilities — populations whose budgets are often more sensitive to economic shocks like the loss of health insurance.

On the other hand, according to the researchers, the Affordable Care Act could also reduce financial shocks and evictions for some families. The program first offered health insurance plans — including low- and zero-premium options — in 2013, well after the period Bradford and her co-authors studied in Tennessee.

Another group expected to be affected, older adults, may be somewhat sheltered from evictions due to savings or Social Security income, according to Bradford and her co-authors, Mir M. Ali of the University of Maryland, College Park and Johanna Catherin Maclean of George Mason University.

The Link Between Medicaid Loss and Evictions

So, what precisely is the connection between loss of Medicaid and eviction?

In the Tennessee case, the loss of health coverage — which persisted for most families removed from Medicaid in Tennessee in 2005 — would likely have added more financial stress to already strapped budgets. It also may have led to a higher incidence of preventable health issues or the undertreatment of existing chronic health conditions that could have made it harder for people to keep working, according to the researchers. Either situation could be financially devastating, potentially resulting in eventual eviction.

Evictions, in turn, often force people into housing located in areas with fewer employment opportunities and higher crime, further elevating the financial stress on vulnerable populations, leading to a cycle that can lock people — especially those affected by health issues or substance misuse — into nearly inescapable poverty, according to the study authors.

“We know evictions are extraordinarily damaging to families and individuals and can cause generational impacts. So we really need to be able to intervene and help vulnerable people before they get into a cycle where they cannot get out of it on their own,” Bradford said.

Bradford said one policy that could help would be a strong, temporary eviction moratorium similar to the one imposed nationally by the U.S. Centers for Disease Control and Prevention in response to the Covid-19 pandemic in 2021. Policymakers could also consider financial assistance to those being removed from the Medicaid rolls to help them stay on their feet during the transition, she said.

Methodology and Limitations

To reach their conclusions in the recent paper, Bradford and her co-authors used data from the Eviction Lab at Princeton University. They examined county-level eviction data from Tennessee and compared it to those of Alabama, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Texas, Virginia, Washington, D.C., and West Virginia.

After controlling for variables such as whether political factors could have led to weakened rental protection laws, they found that the average annual eviction filings per Tennessee county increased by 27.6% as compared to counties in the other states in the U.S. Census Bureau’s South region. Eventual evictions increased by the slightly smaller 24.5% figure.

That works out to about 1,000 more annual evictions per Tennessee County than in other Southern states during the same period.

The study does have some limitations in addition to how much has changed since 2005, Bradford notes. She said the database has some gaps, lacks individual-level data, and does not track eviction notices or evictions overturned on appeal, although the latter is believed to be rare.

Probing Impact of Substance Abuse, Psychiatric Care Access, on Evictions

Bradford’s earlier research has examined the impact of evictions from other angles. In a 2019 paper published in Health Services Research, she also found that a 1% increase in the eviction rate is associated with an up to 0.596% chance of substance-related deaths for the average U.S. county.

In a 2023 study published in the Journal of Policy Analysis and Management with co-author Johanna Catherin Maclean, Bradford found that having ten additional psychiatric treatment centers in a county was associated with 2.1% fewer evictions.

The researchers hypothesized that increased access to psychiatric care improved the management of mental health disorders, which can lead to higher rates of employment and lower rates of activities likely to lead to eviction — such as nuisance behaviors or criminal activity.

It was one of the first papers to make a plausible link explaining the relationship between mental health treatment access and eviction, according to the researchers.

Bradford’s most recent paper, “TennCare Disenrollment Led to Increased Eviction Filings and Evictions in Tennessee Relative to Other Southern States,” was published on Feb. 5, 2024, in Health Affairs. It is available at https://doi.org/10.1377/hlthaff.2023.00973.

The School of Public Policy is a unit of the Ivan Allen College of Liberal Arts.

Georgia AIM, part of Georgia Tech's Enterprise Innovation Institute, works to drive AI adoption to lead the next revolution in U.S. manufacturing across all sectors, geographies, communities, and across underrepresented constituencies.

Its mission is to serve all Georgians, including rural residents, women, Black, Indigenous, and People of Color (BIPOC), those living with disabilities, and veterans. Historically, these groups have been underrepresented in manufacturing.

The White House selected Georgia AIM among the many Build Back Better-funded projects to highlight the importance of community-based work in achieving equity. Below are Ennis’ prepared remarks for the event. With Ennis was Don Graves, deputy secretary of commerce, and former Columbia, South Carolina Mayor Stephen K. Benjamin, a senior advisor to President Joe Biden.

Thank you, Secretary Raimondo and Mr. Benjamin, for this opportunity to discuss how critical the Build Back Better funding has been to our efforts in Georgia in promoting equity.

The Georgia Artificial Intelligence in Manufacturing project (or Georgia AIM) is dedicated to fostering the equitable development and deployment of innovation and talent in AI for manufacturing. Through new innovative approach to funding, that is a coalition model, EDA has provided a pathway for us to develop a network of over 40 partners across the state, including educational institutions, community organizations, and local agencies, to establish an ecosystem unlike any other focused on workforce development, technology innovation, and resilience in manufacturing.

Georgia AIM’s projects are strategically different in communities across Georgia, because they are tailored to those communities’ specific needs. From boosting robotics competitions in K-12 education to enhancing hurricane resilience and aiding local manufacturers, our grassroots approach ensures meaningful outcomes.  This has all been enabled through the Build Back Better funding.

Our customized approach means these innovations can significantly impact lives in Georgia’s rural areas, as well as in communities that are historically underrepresented in manufacturing—in particular, women, people of color, veterans, and members of the workforce without a college degree.

For example, just a few weeks ago, we welcomed our first 18 graduates of a Georgia AIM-sponsored AI robotics training program at the Georgia Veterans Education Career Transition Resource Center. Graduates transition to jobs with Robins Air Force Base, internships with Georgia Tech’s Advanced Manufacturing Pilot Facility, or private industry around the state.

And because of this funding, mobile labs developed by the Russell Innovation Center for Entrepreneurship, University of Georgia, and HBCU Fort Valley State University will extend our reach to rural communities and communities of color, introducing them to smart technologies. These labs are equipped with examples of virtual reality, sensors, robotics, and 3-D printing, with instructors and custom curricula to introduce residents to these new technologies.

Among manufacturers, Georgia AIM has reached nearly 150 small and medium manufacturers including, rural, women-, veteran- and minority-owned companies to help them understand smart technologies.

Funding for Georgia AIM is allowing Georgia Tech’s Advanced Manufacturing Pilot Facility to nearly double its footprint and incorporate a new suite of smart tools and demonstration projects. Already, this facility has partnered with dozens of manufacturers, offering internships and apprenticeships, and guidance to manufacturers of all sizes. In the past year alone, more than 140 companies have learned about AI integration through tours of the facility.

While I could go on and on about how the Build Back Better funding is helping Georgia, I want to emphasize that Georgia AIM’s focus is strategic. We are building a foundation for an innovation economy in a part of the country that historically has not experienced this level of investment from the Federal government. Because of this investment, our AI-based solutions for manufacturers and STEM education efforts are customized for communities, creating a framework that can be replicated across the country. But underlying all of this is equity. We are building an ecosystem that uses AI to solve problems and create innovations for all communities—and, over time, create a template that can then be used to lift up communities across the country. Please visit Georgiaaim.org for more details about our project.

Watch the full event.

From Parkinson’s and Alzheimer's to cardiac arrhythmia, amyloids are linked to a number of diseases. These aggregates of proteins form in the body when a protein loses its normal structure and misfolds or mutates. And since many of these proteins are large and complicated, just how some of these mutations occur and aggregate remains a mystery — as does the creation of effective treatments.

New research on glaucoma led by Georgia Tech chemists and an alumna may help change that.

“There has been a lot of work done to understand how smaller folded proteins form amyloid aggregates, but this study helps us to understand the aggregation pathway of a larger, more complex system,” says co-first author Emily Saccuzzo. That work could one day help scientists uncover new modes of treatment — not just for glaucoma, but for other diseases caused by protein aggregation, as well.

Saccuzzo started the project in 2018 as a graduate student in the Lieberman Lab in the School of Chemistry and Biochemistry at Georgia Tech, and is now a Postdoctoral Research Associate at Pacific Northwest National Labs. “Emily was a summer student before she matriculated, and she established the initial feasibility of doing these experiments,” says Raquel Lieberman, profesor and Sepcic Pfeil Chair in Chemistry at Georgia Tech. “I'm immensely proud of her.”

Their research team's recent findings are featured in a new paper, “Competition between inside-out unfolding and pathogenic aggregation in an amyloid-forming β-propeller," published in the journal Nature Communications.

Lieberman and Saccuzzo brought together researchers from throughout and beyond the Institute to collaborate on the study.

“This was a very multi-disciplinary project, and that's always really satisfying,” Lieberman says. “I think when you bring more people to the table, you can answer hard questions and do more than you can do on your own.”

The Georgia Tech research team includes Hailee F. Scelsi, Minh Thu Ma, and Shannon E. Hill of the School of Chemistry and Biochemistry; Xinya Su and Matthew P. Torres of the School of Biological Sciences; Elisa Rheaume or the Interdisciplinary Graduate Program in Quantitative Biosciences; and James C. Gumbart, who holds joint appointments in the School of Chemistry and Biochemistry, School of Biological Sciences, and School of Physics. The research team also includes Saccuzzo's co-first author Mubark D. Mebrat, Minjoo Kim, and Wade D. Van Horn of Arizona State University as well as Renhao Li of the Emory University School of Medicine.

A complicated protein

While many studies have focused on smaller proteins, called model proteins, that have established ‘rules’ and known patterns for amyloid-formation (a specialized type of protein aggregation), the protein that contributes to glaucoma is larger and more complex. This type of larger, complicated protein is relatively unstudied.

“We had known for a while that mutations in myocilin can cause the protein to misfold and aggregate, which in turn leads to glaucoma,” Saccuzzo says. “What we didn’t know, however, was the exact mechanism by which this protein misfolds and aggregates.

“The goal of this study was to determine how disease mutants are misfolded, in hopes that that would give us insight into the early steps in the aggregation pathway,” she adds.

Located at the interface between the white of the eye and the colored iris, the protein forms a tiny small ring all the way around the eye. “Every time you blink, you stretch that muscle. Every time the wind blows really strong, or you get something in your eye. Every time you rub your eye, you could be affecting this protein — even when it's not causing disease,” Lieberman says. Still, scientists aren’t sure what the protein does. “We only know what it's doing when it's causing trouble,” like glaucoma, she explains. “We don't know what its actual biological function is.”

Lieberman was initially attracted to the idea of studying the protein because she wondered if the research done on the model proteins might be applicable to the protein causing glaucoma. “The really early studies showed that it was likely similar to these model proteins that form amyloid,” Lieberman says. “I wanted to look into that because if we could show that that was true, then we could tap into the amazing resources and research done on model systems to help us combat the disease.”

An unpredictable system

“This was one of the largest amyloid-forming proteins characterized to date,” Saccuzzo says, and while the team hoped that they would find similarities to model proteins, the larger glaucoma-associated protein showed increased complexity.

“I think one of the most surprising observations that we made is that the protein itself is not at equilibrium for about 90 days after it’s made,” Lieberman adds. “One of the tenets of protein chemistry is that amino acid sequences adopt a unique structure, and that all of the information needed to fold the protein into its 3D structure is held in that amino acid sequence.”

Here, the protein was shimmying a small amount, meaning that it wasn’t at equilibrium. “There's so much more going on in the system than anyone could have imagined,” Lieberman explains. “We assume that the shape controls some of the properties, but this is another mystery of this protein.”

Because the protein is so complicated and isn’t at equilibrium, “there is a long list of the things we can’t predict,” says Lieberman, adding that it makes computer predictions difficult, along with certain experiments. “That was a moment when we thought: wow, here's this new system that people should think about. The rules might be refined to help us better understand what's going on.”

The future of protein modeling

While further research will need to be conducted in order to determine how best to treat glaucoma, the study provides a critical foundation for future studies. “What is not clear to me right now is whether we would be able to find one drug for all the people who have mutations, or if we need a specific drug for each type of mutation that we would encounter,” Lieberman says. While the research doesn’t prove that one treatment might not be effective for all, “it certainly shows that there's a lot more to this system than we ever expected.”

“Understanding what disease mutants look like at the molecular level could help pave the way for structurally-specific glaucoma therapeutics and diagnostic tools,” Saccuzzo adds.

Lieberman and Saccuzzo also underscore that the work done to understand the protein responsible for glaucoma can also be applied to other large proteins.

“At the end of the day, more proteins are not model proteins than are model proteins,” Lieberman says. “There are many more systems out there, and I suspect that there are many more proteins that can aggregate and may contribute to disease or aging that have yet to be explored. I think this research shows the value of bringing lots of different approaches to probing a complicated system to learn more about it.”

DOI: https://doi.org/10.1038/s41467-023-44479-2

Research reported in this publication was supported by the National Institutes of Health award numbers R01EY021205 (RLL, WVH), R41EY031203 (RLL), R01GM123169 (JCG), and R35GM141933 (WVH). EGS, HFS, and MTM were supported in part by 5T32EY007092-35.

Raquel Lieberman's research is supported by the Kelly Sepcic Pfeil, Ph.D. Faculty Endowment Fund.

Demand for critical minerals and rare earth elements is rapidly increasing as the world accelerates toward clean energy transitions. Concerns about price volatility, supply security, and geopolitics arise as reducing emissions and ensuring resilient and secure energy systems become increasingly crucial.  

 To address this important area, 45 participants from academia, government, industry, and national labs gathered at the University of Georgia for the inaugural Georgia partnerships for Essential Minerals (GEMs) Workshop. The workshop was the first in a series of critical mineral conversations planned by the collaborators of the workshop. The first GEMs Workshop focused on the critical mineral potential in Georgia’s kaolin mining industry.  

 Key workshop conveners included W. Crawford Elliott, associate professor of chemistry and geosciences at Georgia State University; Lee R. Lemke, secretary and executive vice president of the Georgia Mining Association; Paul A. Schroeder, professor in clay minerology at the University of Georgia; and Yuanzhi Tang, associate professor in the School of Earth and Atmospheric Sciences at Georgia Tech. 

 Representatives from more than 20 companies, the Environmental Protection Agency, U.S. Geological Survey, Georgia Environmental Protection Division, and Savannah River National Laboratory, as well as faculty members and students from Georgia’s three R1 universities participated in the day-long workshop. Speaker sessions and panel discussions addressed: 

• Developing a state and regional ecosystem demonstrating a critical mineral supply chain from resources to solutions to end users. 
• A strong emphasis on workforce training for this emerging industry.  
• Establishing a regional critical mineral consortium to facilitate resource exploration, characterization, processing, and utilization.
• Creating official industry-university collaborations that included internships, field trips, curricular training, R&D collaboration, and stakeholder liaisons. 

 Workshop organizers plan to reconvene in six months to continue conversations and build momentum on critical minerals research, from supplies to workforce training and beyond. 

The Georgia Institute of Technology today announced the signing of a master research agreement with Micron Technology, a global leader in memory and storage solutions. Under the new agreement, the two organizations will expand their collaborative efforts in providing students with experiential research opportunities and expanding access to engineering education.

“We are proud to join forces with Georgia Tech, home to some of the nation’s top programs, to expand students’ opportunities in STEM education,” said Scott DeBoer, executive vice president of Technology and Products at Micron. “This collaboration will help push the boundaries in memory technology innovation and ensure we prepare the workforce of the future.”

“We believe that when academia and industry converge, the best ideas flourish into game-changing innovations,” said Chaouki T. Abdallah, executive vice president for Research at Georgia Tech. “The synergy between Micron and Georgia Tech has already been tremendously fruitful, and we are so excited for the boundless opportunities on our shared horizon.”

“The signing of the master research agreement represents a significant step towards increasing additional collaboration pathways between Micron and GT including the joint pursuit of major federal funding activities, technology transfer, student internships and technology transfer,” said George White, senior director of Strategic Partnerships at Georgia Tech.

The first project under the agreement is already underway. Saibal Mukhopadhyay, professor in the School of Electrical and Computer Engineering, is leading the research efforts titled “Configurable Processing-In-Memory.” This cutting-edge research will enable memory devices to work faster and more efficiently.

It doesn’t have to be Valentine’s Day for Flavio Fenton to have the heart on his mind. Fenton has been fascinated by the human heart for 30 years. The professor in the School of Physics explores the physics and mathematics behind the heart — specifically, arrythmias, or abnormal heart rhythms.

“When you think about the physics of a heart, the first thing that comes to mind is the pumping action and the forcing of fluids,” he said. “But the reason it contracts is an electrical signal. There’s a lot of physiology and biology behind the function of the heart, but underneath it all, there’s so many areas of physics you can apply to it to understand how it works — and how it fails to work, like in the case of arrhythmias.”

There’s a lot to love about Fenton’s work:

• Last year, Fenton and clinicians at Emory University won the Georgia Clinical and Translational Science Alliance's Team Science Award of Distinction for Early Stage Research for their work using live explanted human hearts to better understand arrhythmias.
• In 2022, Fenton and his collaborators brought a new understanding to complicated heart conditions with the first high-resolution visualizations of stable spiral waves in human ventricles.
• During the Covid-19 pandemic, his research revealed the cardiac risks associated with the proposed use of hydroxychloroquine in treatment.
• The year before, Fenton used graphics processing chips designed for gaming applications and software that runs on ordinary web browsers to move the modeling of deadly heart arrhythmias to less costly computers, and even to high-end smartphones.
• In 2018, Fenton and a team came up with a new imaging technique that could lead to earlier identification of heart rhythm disorders and the development of better treatments.

His current projects involve possible advances in the amount of voltage used to treat fibrillations, and new knowledge about where in the heart to apply that voltage. He maintains collaborations with agencies like the Food and Drug Administration and a wide array of researchers and clinicians, with hopes that hospitals will eventually be able to apply what he has studied over the years to assist in better patient care and health outcomes. 

“The heart has been a really fun system to study, and there’s so much that we still don’t know,” he said. “On top of that, it has a main application of directly saving lives if we can find better and safer ways to prevent and terminate arrhythmias.” 

Are our bodies solid or liquid? We all know the convention — that solids maintain their shapes, while liquids fill the containers they’re in. But often in the real world, those lines are blurred. Imagine walking on a beach. Sometimes the sand gives way under feet, deforming like a liquid, but when enough sand grains pack together, they can support weight like a solid surface.

Modeling these kinds of systems is notoriously difficult — but Zeb Rocklin, an assistant professor in the School of Physics at Georgia Tech, has written a new paper doing just that. 

Rocklin’s study, “Rigidity percolation in a random tensegrity via analytic graph theory,” is published in the journal Proceedings of the National Academy of Sciences (PNAS). The results have the potential to impact fields spanning biology to engineering and nanotechnology, showing that these types of deformable solids offer a rare combination of durability and flexibility.

"I'm very proud of our team, especially Will and Vishal, the two Georgia Tech undergraduates who co-led the study,” Rocklin says. 

The lead author, William Stephenson, and co-author Vishal Sudhakar both completed their undergraduate studies at the Institute during the time of this research. Stephenson is now a first-year grad student at the University of Michigan, Ann Arbor, and Sudhakar has been admitted to Georgia Tech as a graduate student. Additionally, co-author Michael Czajkowski is a post-doctoral researcher in the School of Physics, and co-author James McInerney completed his graduate studies in the School of Physics under Rocklin. McInerney is now a postdoctoral researcher at the University of Michigan. 

Connecting the dots… with cables

Imagine building molecules in chemistry class — large wooden spheres connected with sticks or rods. While many models use rods, including mathematical models, biological systems in real life are constructed of polymers, which function more like stretchy strings.

Likewise, when creating mathematical or biological models, researchers frequently treat all the elements as rods as opposed to treating some of them as cables, or strings. But, “there are tradeoffs between how mathematically tractable a model is and how physically plausible it is,” Rocklin says. “Physicists can have some beautiful mathematical theories, but they aren’t always realistic.”  For example, a model using connective rods might not capture the dynamics that connective strings provide. “With a string you can stretch it, and it'll fight you, but when you compress it, it collapses.”

“But, in this study, we’ve extended the current theories,” he says, adding cable-like elements. “And that actually turns out to be incredibly difficult, because these theories use mathematical equations. In contrast, the distance between the two ends of a cable is represented by an inequality, which is not an equation at all. So how do you create a mathematical theory when you aren't starting from equations?” While a rod has a certain length in a mathematical equation, the ends of the string have to be represented as less than or equal to a certain length.

In this situation “all the usual analytic theories completely break,” Rocklin says. “It becomes very difficult for physicists or for mathematicians.”

“The trick was to notice that these physical systems were logically equivalent to something called a directed graph,” Rocklin adds, “where different modes of deformation are linked to each other in specific ways. This allows us to take a relatively complicated system and massively compress it to a much smaller system. And when we did that, we were able to turn it into something that becomes extremely easy for the computer to do.”

From biology to engineering

Rocklin’s team found that when modeling with cables and springs, the target range changed — becoming softer, with a wider margin for error. “That could be really important for something like a biological system, because a biological system is trying to stay close to that critical point,” says Rocklin. “Our model shows that the region around the critical point is actually much broader than what models that only used rods previously showed.”

Rocklin also points out applications for engineers. For example, since Rocklin's new theory suggests that even disordered cable structures can be strong and flexible, it may help engineers leverage cables as building materials to create safer, more durable bridges. The theory also provides a way to easily model these cable-based structures, to ensure their safety before they are built, and provide a way for engineers to iterate on designs.

Rocklin also notes potential applications in nanotechnology. “In nanotechnology, you must accept an increasing amount of disorder, because you can't just have a skilled worker actually go in and put segments there, and you can't have a conventional factory machine put segments there,” Rocklin says. 

But biology has known how to lay down effective, but disordered, rod and cable structures for hundreds of millions of years. “This is going to tell us what sorts of machines we can make with those disordered structures when we're getting to the point of being able to do what biology can do. And that's a possible future design principle for the engineers to explore, at very small scales, where we can't choose exactly where each cable goes,” Rocklin says.

“Our theory shows that with cables, we can maintain a combination of flexibility and strength with much less precision than you might otherwise need.”

Funding: This research was funded by the Army Research Office through the MURI program (#W911NF2210219).

DOI: https://doi.org/10.1073/pnas.2302536120

Figure caption: Systems of rigid rods acquire rigidity via the addition of random additional rods and cables, as captured via a graph theory. The research team's main object of study, shown here, is structures that consist of large numbers of pores — arranged in columns and rows with cables and rods added at random.

U.S. News & World Report has ranked the Georgia Institute of Technology as the top public university and No. 3 nationally in energy and fuels research. This is the first year the category has been included in the annual rankings, and Georgia Tech’s dominance reflects the dynamic research and expertise of the Institute.

“I’m thrilled to see Georgia Tech recognized for our leading-edge approach to creating sustainable energy solutions,” said Executive Vice President for Research Chaouki Abdallah. “This achievement reflects the unwavering commitment of our faculty and researchers to conducting groundbreaking research, transformative innovation, and our dedication and focus through our Strategic Energy Institute (SEI) to addressing the world's most pressing energy challenges.”

SEI integrates energy research across Georgia Tech and is one of 10 Interdisciplinary Research Institutes. Headed by Executive Director Tim Lieuwen, Regents’ Professor and David S. Lewis Jr. Chair, SEI helps connect and integrate the large Georgia Tech energy community for engagement with industry, government, communities, and nonprofits.  

 “Georgia Tech has over 1,000 researchers working on the clean energy transition across every school, college, and unit,” said Lieuwen. “I’m pleased to see the scale of our impact recognized by this ranking but also energized by the real-world impact that we are having on cleaner air, lower cost energy, and a healthier planet.”

 U.S. News & World Report ranks 47 subject areas by tabulating academic research performance such as publications and citations, and indicators for regional and global reputation. Georgia Tech was evaluated out of 319 universities, and continues its strong standing in the rankings, claiming the No. 33 spot overall in the nation and No. 10 among public schools.