There is a place in the United States just outside Dayton, Ohio, where human beings willingly buckle themselves into a giant centrifuge capable of exerting 20 times the force of Earth’s gravity, or 20 Gs. Wright-Patterson Air Force Base houses a machine that simulates the conditions of high-speed flight; it is used to conduct research and testing and to train fighter pilots, flight surgeons, aerospace physiologists and others. 

Braden Li, who is pursuing his Ph.D. in Fiber and Polymer Science here at the Wilson College of Textiles at NC State, had the opportunity to see the centrifuge in action this summer — and will one day return to the facility as an employee. He has received the Science, Mathematics and Research for Transformation (SMART) scholarship through the Department of Defense (DOD). 

While in school, SMART scholarship recipients — who are each sponsored by a DOD facility — receive full tuition, monthly stipends, health insurance and book allowances, plus summer internships. Once they graduate, recipients begin working in a civilian capacity at the sponsoring facility.  

“My sponsor is the Air Force Research Laboratory and what they want to work on is high altitude wearable technology,” said Li. “When it comes to high altitude wearables, a lot of them actually don’t work [in flight] — at least the ones they’ve been trying to use — because the electronics break.”

The Research

Li is a graduate researcher with the Nano-EXtended Textiles (NEXT) Research Group, led by Textile Engineering, Chemistry and Science (TECS) professor Jesse Jur, and conducts research for the Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), which aims to develop self-powered sensing, computing, and communication systems for applications such as healthcare and the internet of things; their current research focuses on energy harvesting and storage, smart textiles, emerging materials and more.

“ASSIST wants to develop what they’re calling their self-adaptive platform (SAP),” said Li. “They want to make a wearable device that is essentially self-powered, and you can also switch different sensors in and out.”

To that end, Li has been working to improve the design of a shirt that functions as a self-powered electrocardiogram (ECG), but will one day be able to do much more.

“ASSIST is beginning to ask, ‘What other sensors can we integrate into the shirt?’ [For example], they’re looking at ozone for asthma,” said Li. “They’re trying to do wound sensing, so if [a patient has] a wound, they can have sensors on their skin that provide real time measurements to improve wound management strategies as opposed to just delivering medication. That one’s a little bit further out, but they are looking at some really cool stuff.”

Li’s contribution to the shirt project is an innovative design change. 

“Just to give you background information, once I put on the shirt, these sensors start monitoring my heart rate,” said Li. “If I start moving around, that heart rate signal will look kind of choppy. That’s [the result of] what people in this field call motion artifacts. So [the group] tried to design the shirt with multiple panels with the idea that in each of these panels, the textile has different mechanical properties. There’s different levels of stretch throughout the shirt, and what that does is mitigate those motion artifacts.”

However, constructing a garment of multiple textiles can be laborious and costly. Li came up with an alternative idea inspired by an ephemeral art form.

“Origami is paper folding,” he said. “‘Ori’ literally means to fold and ‘gami’ means paper. Kirigami, on the other hand, means to cut paper. By cutting and folding paper, you’re actually able to make paper that’s not normally stretchable very stretchy — think of 3D pop-up books. I read a couple of research papers by people working [with kirigami], but nobody has done this on a textile yet. Construction of these types of garments would not be complicated with kirigami. All you really need is a laser cutter [and] I could just cut in areas where I need different mechanical properties. Manufacturing time will be a lot quicker. You can personalize the design depending on what the person wants.”

A functioning shirt with kirigami design would not only be cheaper — it would more effectively power its own sensors. 

“One of the more promising avenues is mechanical harvesting. You’re always moving, but the problem is that you’re moving at a very low rate; not only that, but you’re moving in all sorts of directions. The current mechanical harvesters aren’t that flexible and they can’t harvest energy at those very low rates of moving — like breathing. You’re looking at some frequencies of less than one hertz. [But] with kirigami you can actually make [the garment] more stretchable and open up new avenues for energy harvesting.”

Li believes that the flurry of creativity and activity in Jur’s lab, as well as the freedom to explore, has bolstered his confidence as a researcher.

“His lab is a little faster paced [compared to my lab in undergrad],” said Li. “At first, it was kind of out of my wheelhouse — I was very used to the traditional academic sense. I like [Jur’s] mentorship style because it’s very open and he gives me a lot of room to explore my own ideas and create. What I really like about it is the freedom he gives you. The kirigami idea was my idea and he was like, ‘Go for it. Get lost in it.’ But sometimes I get too lost, so at the same time, I need him to kind of like pull me out. He’s a big idea guy, so he’s always throwing ideas at you…It’s really cool to see that and get that insight, because that’s something I can really expand on and try to work on. He’s really creative.”

Li counts Jur as a mentor, along with several other teachers and professors who he says have strengthened his work ethic, sharpened his focus and fueled his interest in STEM.

“My high school track and cross country coach, Johan Odermatt, really pushed me — he pushed us every day,” he said. “Another high school teacher, Dr. Yvette De la Vega, has been a huge mentor. She was one of my high school teachers and then she went back to get her doctorate in English. Dr. Nancy Ruzycki was my undergrad lab teacher. She was the first one to really believe in me in terms of an engineering sense, which gave me the confidence to do what I’m doing now. Dr. Jennifer Andrew was my research mentor and we got really close, too.”  

Background

Li is from Miami, Florida, where he grew up surrounded by a big, diverse family.

“My family is interesting. My dad’s side is Cuban and Chinese. My grandfather migrated from China to Cuba, met my grandma there and then came to the United States. On my mom’s side, they’re all from Hong Kong. There’s like 16 great aunts and a lot of cousins — it’s a huge family from all over the place,” he said. “My favorite holiday growing up was Christmas Eve, or Nochebuena, which basically means good night. For us, it’s an excuse to get the family together and eat. We would roast a whole pig. On the Chinese side, we bring all the Chinese food and my grandma would bring the Cuban food.”

Since childhood, Li wanted to become an engineer.

“It was always engineering,” he said. “My dad studied industrial science and engineering at the University of Florida and then my cousin, and then another cousin studied engineering, too. They were all like, ‘You have got to get into UF.’”

He did go on to attend the University of Florida, where he majored in Materials Science and Engineering. While there, he interned at Medtronic, a large medical device company. As graduation loomed, he had to make some big decisions about his future.

“My buddy Wade [Ingram] and I worked in the same lab back in undergrad,” he said. “He came here for his Ph.D. — we both work for Dr. Jur now — and he said I should look into the Wilson College of Textiles. I was kind of on the cusp of grad school and industry, but after coming here for a visit and meeting with Dr. Jur, I was like, ‘Yes. This is the place I want to be.’” 

The SMART Scholarship

Li’s scholarship officially begins this semester, and to prepare, he toured the DOD facility that will fund his research. He didn’t get to test out the giant centrifuge, but he did get a little taste of fighter pilot training.  

“They put me in a Barany chair, which is a frictionless metal chair with a bar around it,” he said. “What happens with pilots is that the fluid in your ears, if you start turning too fast in your plane, it levels out — so you lose your sense of direction. You don’t know what is up, down, left or right….After about three or four spins, I lost it completely. The officer was spinning me around and I could hear her rings banging on the metal — but I didn’t know where she was. I knew she was to the left of me, but I didn’t know what left was anymore. It was crazy. Imagine being in a dark cave and you close your eyes and hear water dripping all over the place, but you don’t know if it’s dripping down or dripping up. I opened my eyes and tried focusing on something but my eyes were darting all around. The condition is a form of spatial disorientation called The Coriolis Illusion. There’s no sense of direction and their eyes go all over the place.”

Li is looking forward to beginning his career with the DOD after graduation and hopes to stay there for some time, although he likes the idea of one day working for a larger technology company like Google or Apple or a big-name sports outfitter like Nike or Adidas. Eventually, he may find his way back to academia to become a mentor to a new generation of students. 

“This past summer I’ve had a chance to work with a lot of high school students through ASSIST and I have been working with another undergrad also through ASSIST,” he said. “I really enjoyed the mentorship and teaching. It’s really neat to see them learn and I like to teach people stuff that I wish I was taught when I was that age — to kind of give them the cheat codes to life.” 

 

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