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ORNL staff fellowships launch careers in science

4 images starting with a woman in a purple long sleeve and white sun hat; woman in black sleeveless blouse with blond hair; man in blue suit and tie ; man with blue collared shirt and glasses.
From left, Distinguished Staff Fellowship alumni Melissa Cregger, Andrea Delgado, Michael McGuire, and Guannan Zhang. Credit: ORNL, U.S. Dept. of Energy

Melissa Cregger, Andrea Delgado, Michael McGuire and Guannan Zhang all are successful researchers who work in different scientific fields of study: Cregger is an ecosystem ecologist; Delgado, a quantum physicist; McGuire, a materials physicist; and Zhang, a computational mathematician. 

Although their fields appear to have little in common, one thing they all share is that they were each named a Distinguished Staff Fellow, or DSF, at the Department of Energy’s Oak Ridge National Laboratory. The ORNL scientists started their professional careers as staff scientists in the DSF program, a highly competitive, prestigious program for young scientists to begin a lifetime vocation in research at the lab.

“What the fellowship did, first, was get me here,” said McGuire, a 2007 Eugene P. Wigner Fellow and now Correlated Electron Materials group leader who won the UT-Battelle Director’s Award for Outstanding Individual Accomplishment in Science and Technology in 2023. “I don’t think I would have ended up here by any other path. What it also did was really helped me in terms of networking, which I personally am bad at. It started me out with a certain amount of natural interaction with other people at the lab, and I think that led to opportunities that were provided to me that really helped move my career along.”

McGuire noted, “I have been fortunate to have stable and continued support, from the beginning of my fellowship through today, from the DOE Office of Science Basic Energy Sciences program, to pursue my interests in developing and understanding electronic and magnetic materials.” 

In the years following his fellowship, McGuire was also involved in establishing ORNL’s role in the Critical Materials Institute, an applied research center led by Ames National Laboratory. He was also involved in the founding of the Quantum Science Center, a DOE National Quantum Information Science Research Center headquartered at ORNL, in which he leads one of three research areas, Quantum Materials Discovery and Development.

“My involvement in both basic and applied research, and my success here at the lab, goes back to, as a Wigner Fellow, the freedom to pursue different directions. Really that’s what got everything started for me,” McGuire said. 

The fellowships are named for renowned scientists who made significant contributions to their scientific field and held leadership positions at ORNL: Liane B. Russell, Alvin M. Weinberg, Eugene P. Wigner and Alston S. Householder.

Fellows represent a broad range of disciplines that span ORNL’s mission to deliver scientific discoveries and technical breakthroughs needed to realize solutions in energy and national security and provide economic benefit to the nation. The fellowship program provides internal Laboratory Directed Research and Development funds, or for the Householder fellowship, DOE funds, to allow young scientists to grow new research areas within the laboratory. The goal: cultivating future scientific leaders with mentors, resources and the research opportunities afforded by a national laboratory.

For Cregger, a senior staff scientist, the fellowship in 2015 afforded her the opportunity to meet and network with other Fellows who helped her understand how a national lab operates. “We had monthly meetings, and it taught us the inner workings of the lab,” Cregger said. “We focused on networking and collaboration within our cohort, with other fellows who were spread around the whole laboratory across scientific disciplines.”

From the 2015 cohort of nine staff members, six of them, including Cregger, won DOE Early Career Awards, a testament to the leader of the program at the time, senior R&D staff member John Neal.

“The fellowship provided a bit of a safety net in the way that it is built because you develop new areas of research, while at the same time working on core ORNL programs in addition to your fellowship,” Cregger said. “This allows you to do something new without being completely isolated. You’re still doing team science.”

When she started, Cregger focused her fellowship research on disturbance effects on forests and alterations in soil carbon cycling. Her mentor was Chris Schadt. This work contributed to the success of her 2021 DOE Early Career Award, which focuses on constructing optimal plant “holobionts” — the biological units consisting of a plant host plus all the symbiotic microorganisms associated with the plant. Within her research, she is particularly interested in increasing plant resilience and altering soil processes by strategically manipulating belowground plant–microbe interactions.

Zhang, a senior scientist in the Computer Science and Mathematics Division, works in applied mathematics for machine learning, developing algorithms used in artificial intelligence. A 2012 Householder Fellow, Zhang also won a DOE Early Career Award, in 2023, selected by DOE’s Advanced Scientific Computing Research Program for his proposal, “Advanced Uncertainty Quantification Methods for Scientific Inverse Problems.”

Zhang’s research focuses on how to quantify uncertainties in scientific models, which describes the confidence of a prediction of a model, whether a traditional physical model or an AI model. “Even in AI right now, it becomes even more important because we don’t know how exactly an AI model would work or would not work,” Zhang said.

Zhang echoed Cregger and McGuire, reiterating that the Fellowship program was extremely useful to his ability to grow his career.

“It’s very flexible,” Zhang said. “There was no constraint on what specific problem we should focus on. So I took that opportunity and established collaborations without any constraints. I got to know many people, many scientists in other directorates during that time. I have collaborations right now with almost all the directorates at Oak Ridge. If you trace it back, how did that happen? The starting point was I had this fellowship, which gave me the best flexibility.”

Delgado, a 2020 Eugene P. Wigner Fellow, had little support in her research area because no one else at the lab was doing exactly what she was researching — applying quantum computer applications to high-energy physics to learn about the fundamental building blocks of the universe. Specifically, she was designing algorithms to analyze massive amounts of complicated data from large-scale high-energy physics experiments. The physicists knew little about applying quantum computing, and the quantum computational researchers knew little about high-energy physics. 

Under fellowship mentor Marcel Demarteau, director of the Physics Division at ORNL, Delgado was able to combine the two fields and to position herself as a leader. “I got the opportunity to be in the field when it was just becoming a thing,” Delgado said. “It was always a challenge to bring those two fields together to get a collaboration going.”

Now awaiting word on a DOE Early Career Award, Delgado said the fellowship gave her visibility in a field where minority women are underrepresented. Additionally, as a fellow or former fellow, she was keynote speaker at several international conferences, organized several workshops on the interdisciplinary topic and was the youngest associate editor of the journal IEEE Transactions on Quantum Engineering.

As a recipient of a Reaching a New Energy Sciences Workforce, or DOE RENEW, grant to encourage underrepresented minorities to go into STEM fields, Delgado runs an internship program for minority-serving institutions and regularly hosts interns through DOE or ORNL programs. The program’s goal: diversifying the next generation of scientists and engineers. “We have a chance to actually build the workforce from the ground up,” Delgado said.

McGuire noted,  “One of key things about this fellowship is that there was quite a bit of flexibility and freedom on what I could work on, partly because of the way the fellowship is structured; that was hugely important. Just having recognition from lab leadership, there’s an expectation that DSFs not just be good researchers, but to be leaders themselves eventually.”

ORNL’s Distinguished Staff Fellowship program aims to cultivate future scientific leaders by providing dedicated mentors, world-leading scientific resources and enriching research opportunities at a national laboratory. Fellowships are awarded to outstanding early-career scientists and engineers who demonstrate success within their academic, professional and technical areas. Fellowships are awarded for fundamental, experimental and computational sciences in a wide range of science areas.

UT-Battelle manages ORNL for DOE’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, visit —Lawrence Bernard