When his former Ph.D. advisor died, Joshua Bostwick stepped up to help his academic family

Clemson University’s Joshua Bostwick might not be related by blood to Vanessa Kern and Joshua McCraney, but he considers them siblings in a special way.

All three pursued doctorates under the highly respected Cornell University professor Paul Steen, and they all had a hand in researching a theory that was tested in experiments on the International Space Station.

So when Steen died unexpectedly shortly before the experiments, Bostwick didn’t have to think twice about stepping in to help advise Kern and McCraney, then Ph.D. students at Cornell.

“Josh and Vanessa are basically like my academic brother and sister,” said Bostwick, now the Stanzione Associate Professor of mechanical engineering at Clemson. “They were in a shocking situation, and I would volunteer to help any day of the week.”

The assistance that Bostwick provided to his academic family underscores the lifelong bonds that often form between Ph.D. students and their advisors. Bostwick made those connections in Steen’s lab, and now he is setting the stage for his students to do the same at Clemson.

Atul Kelkar, chair of Clemson’s Department of Mechanical Engineering, said Bostwick filling in for his late advisor highlights a sometimes underappreciated aspect of graduate school.

“The bonds that are forged through common struggle in the lab and classroom often remain strong for years,” Kelkar said. “When students pursue a doctorate, they are receiving more than an advanced education and research experience. They are creating a network that can help support them for the rest of their lives and sometimes even beyond that.”

Chase Gabbard, a Ph.D. student in Bostwick’s lab, said the group is tight-knit and that his advisor does a great job of maintaining a consistent culture, even as students graduate and new ones take their place.

“Dr. Bostwick is the steady ship for the group,” Gabbard said. “He has his expectations, and he applies them to everyone evenly.”

Bostwick studied under Steen for a Ph.D. in theoretical applied mechanics from 2006-11. After receiving his doctorate, Bostwick continued to collaborate with Steen, and they published several papers together.

The first time Bostwick submitted a manuscript to Steen for review, it was returned with an incredible amount of red ink, he said. Steen was creative and professional, and there was a reason he was well-known among those who research fluid mechanics, Bostwick said.

“When I talk to graduate students today, I say that when they work with someone such as an advisor or collaborator, they can take away something they can use when they are advisors,” he said. “What I learned from Paul was attention to detail. Everything had to be top class. He wasn’t putting out anything average.”

Steen, the Maxwell M. Upson Professor in the Smith School of Chemical and Biomolecular Engineering at Cornell, died at age 68 on Sept. 4, 2020. It was a shock to his colleagues because he had seemed to be the picture of excellent health.

“You think about a professor passing, and it’s tragic,” McCraney said. “But unless you are a Ph.D. student, it’s hard to understand the relationship you develop with your advisors. I talked to this man face to face probably twice a week for four years. We went to conferences together.”

When the shock and grief began to subside, it was time to figure out how to keep pushing the research forward.

Kern said all the hardware for the experiments had been delivered so she was confident they would still be performed. But both she and McCraney were close to moving on in their own academic careers, and it wasn’t entirely clear what would happen to the research after the results made it back to Earth.

Bostwick got involved when he received a call from the chair of the chemical engineering department at Cornell. He helped interpret the data, edit manuscripts and figure out which journals would be most interested in publishing the results.

“If it weren’t for Josh Bostwick, I don’t think I could have put together my thesis in time,” said Kern, now a postdoctoral fellow at the University of Oslo in Norway. “He really stepped in and helped me. Every time I would send him something he would respond in a day with notes and suggestions. I am eternally grateful to him.”

The space station experiments, performed in October 2020, used microgravity to shed light on how water droplets oscillate and spread across solid surfaces. The results could have application in 3D-printing, spray cooling, and manufacturing and coating operations.

Joshua Bostwick was named the Stanzione Associate Professor last year.

Researchers published their findings in the journal Physical Review Letters in a paper titled, “Oscillations of Drops with Mobile Contact Lines on the International Space Station: Elucidation of Terrestrial Inertial Droplet Spreading.”

Co-authors are McCraney; Kern; Bostwick; Susan Daniel, William C. Hooey Director of Chemical & Biomolecular Engineering at Cornell; and Steen.

Bostwick said the experiments “put a bow” on about 10 years of research led by Steen.

“It’s heartbreaking that he couldn’t have been around to see that because he convinced us that the theory we developed so long ago is valid for all these regimes,” he said.

But Steen’s legacy is living on through his students, who are now forming academic families of their own and watching their students do the same.

When Gabbard started in graduate school, he was mostly interested in pursuing a master’s degree so that he would be better qualified for research-and-development jobs. But he changed his mind and decided to remain at Clemson for his doctorate, too, after studying under Bostwick.

“He is the reason I stayed after my master’s and to do a Ph.D.,” said Gabbard, who is on track to receive his doctorate in spring 2024. “A lot of what he tells me– he mentions that Dr. Steen said similar things to him.”

Gabbard said he is now interested in finding a postdoctoral fellow position after graduation and to follow a similar path Bostwick did.