PhD mechanical engineering alum awarded prestigious Schmidt Science fellowship to advance concussion research

Recent Purdue University graduate Vahidullah “Vahid” Tac, who completed his doctorate researching the data-driven modeling of biological materials, has been awarded a fellowship from the prestigious Schmidt Science Fellows program.

Tac is now a postdoctoral scholar at Stanford University, studying the biomechanics of mild traumatic brain injury, or concussion, after completing his PhD as a Boilermaker in mechanical engineering in 2024. Originally from Afghanistan, Tac earned his bachelor’s and master’s degrees in aeronautical and astronautical engineering from Middle East Technical University in Turkey.

“The Schmidt Science Fellows program is, without a doubt, one of the most prestigious postdoctoral fellowships in the world. Since the very first time I heard about the program years ago, I have secretly dreamt of one day seeing my own name on the roster of fellows. Today that dream became reality,” said Tac, who will continue his research at Stanford as a Schmidt fellow.

The class of Schmidt fellows of 2025 was announced Wednesday (April 2).

Schmidt Science Fellows is an initiative of the program’s $100 million effort to drive global scientific leadership and interdisciplinary research across society over the next decade and beyond. It awards annual $110,000 fellowships to global leaders and innovators in the natural sciences, engineering, mathematics and computing. In addition to the stipend, the fellowship includes conducting a full-time — 11 months or longer — postdoctoral study in a discipline that differs from the recipient’s existing area of expertise and planned future focus.

“After spending close to four years at Purdue, I can confidently say Purdue has qualities that were an integral part of my success,” Tac said. “It has a unique culture in that a PhD student usually receives equal amounts of freedom and motivation. This helps the students discover their own limits while working toward their goals, and to take ownership of their journey.”

In his PhD research at Purdue, Tac focused on developing mathematical descriptors of the mechanics of soft materials, like rubber and skin, using machine learning. A common element in his PhD publications: develop new ways of enforcing physical laws in machine learning models such that the laws are always satisfied. This is in contrast to other fields of research, he said, where physical constraints are enforced through loss functions, which are not guaranteed to work.

Tac’s journey from Afghanistan to the U.S., through Purdue, Stanford and now as a Schmidt fellow is the stuff of movies. Born into a family with very limited means in a remote part of a country in constant state of war, he said his life has been part refugee, part immigrant. “My life was not all gloom and doom, though, as I was lucky to have had a keen curiosity,” he added. “Through this curiosity, and through the guidance of some key people in my life such as my parents, I strove to continually improve myself.”

Tac won a scholarship to study aerospace engineering in Turkey. There, he said, it dawned on him that airplanes “were actual man-made objects, that there are actual human beings somewhere in the world who are building these things. Not only that, but I could realistically become one of these people one day. This filled me with excitement for the future.”

When he launched into his doctoral studies at Purdue, Tac said, machine learning was revolutionizing a few fields such as image processing. That intrigued him as a mechanical engineer, although it was daunting, too. “How could I possibly learn all these skills? I was in no way prepared to take on this challenge. But guess what? Nobody was. Somebody had to go out, do the hard work of learning all these different skills and apply them to this problem. I decided to be that person,” he said.

Tac studied at Purdue under Adrian Buganza Tepole, an associate professor of mechanical engineering who has a courtesy appointment in biomedical engineering. “Not only is Dr. Tepole a great person and an amazing PhD advisor, but he is also a kind friend and, I dearly hope, my lifelong mentor,” Tac said.

In continuing his research as a Schmidt fellow, Tac’s goal is to understand how impacts to the head result in concussion and how to prevent it. Answering this question is not easy, however, because of the complexities of the human brain. “Therefore, I am trying to utilize all assets that are at my disposal to answer this question, including computational and experimental models,” he said.

So what’s next for Tac after he completes his Schmidt fellowship and postdoc studies? “All I can say for sure at the moment is that I want to provide something of value to society, and to leave important contributions behind,” he said. “Exactly how I will achieve this? Only time will tell.”

Schmidt finalist headed to Harvard

Fellow Boilermaker Dylan Holden, who is finishing his PhD studies in analytical chemistry this semester, also was a Schmidt fellows finalist.

His academic journey will continue as a Chemistry Future Leaders Fellow at Harvard University, working with chemistry and chemical biology professor Christina Woo. As a postdoc there, Holden will focus on developing strategies to better understand how the body responds to and clears damaged proteins, as well as exploring how drugs can be designed to enhance these processes.

“It’s not often that one has the opportunity to completely switch to another field of study without significant risk, but the Schmidt Science fellowship offers exactly that,” said Holden, a native of Waynesboro, Pennsylvania, who earned his bachelor’s degree at Mount St. Mary’s University. “Writing an extensive application and proposal to ‘pivot’ into a new discipline was a challenging process, but it gave me the chance to step back and consider other problems I’m interested in beyond my PhD research and what I might do after my postdoc,” he said.

While not awarded a Schmidt fellowship, Holden said the process was invaluable and rewarding, thanks to the assistance at Purdue from Rachelle Swan, director of the Office for Postdoctoral Scholars, and assistant professor Kurt Ristroph, a past winner of a Schmidt fellowship. The principal investigator on Holden’s research project is Graham Cooks, the Henry Bohn Hass Distinguished Professor of Chemistry at Purdue.

Purdue was restricted to nominating four PhD candidates for the Schmidt Science fellowship, and the nominees were chosen through a rigorous faculty-review process prior to submitting applications. “Having two of our four nominees selected as finalists for the 2025 cohort is an extraordinary accomplishment,” Swan said. “From a global pool of 450 nominated students, only 100 were named finalists, and Schmidt Science praised Purdue for achieving ‘a significant milestone in an exceptionally competitive process.’”

Boilermakers previously awarded Schmidt Science fellowships:

• Susmita Sarkar, who earned her PhD in mechanical engineering at Purdue and completed her postdoc at Stanford, is an assistant professor of mechanical and aerospace engineering at North Carolina State University. She was Purdue’s first Schmidt fellow in 2023.
• Ristroph was a Schmidt fellow in 2021-22 after he earned his PhD in chemical engineering at Princeton University. As a Schmidt Fellow, he completed his postdoc in environmental engineering at Carnegie Mellon University. He is now an assistant professor of agricultural and biological engineering, and chemical engineering (by courtesy) at Purdue.

Launched in 2018, Schmidt Science Fellows is the inaugural program of Schmidt Futures, the philanthropic initiative of Eric and Wendy Schmidt with a mission to find and connect talented people to solve the world’s hardest problems. The program is delivered in partnership with the Rhodes Trust.