FOCUS ON NEW FACULTY:
Associate Professor Tom N. Krupenkin
ssociate Professor Tom Krupenkin enjoys the climate at UW-Madison. Not the weather—although to the Russian native, even a blustery Wisconsin winter seems mild. For Krupenkin, the best thing about working at UW-Madison is the atmosphere of collaboration.
“This is a large university with strong research, a lot of departments, and very strong interactions between the departments—no partitions, no firewalls—so people can work together,” says Krupenkin. “That was very attractive.”
As a researcher with backgrounds in physics, polymers, mechanics, interfaces and liquids, Krupenkin values interdisciplinary interaction. He joined the College of Engineering after nine years as a technical staff member at Bell Laboratories in New Jersey. His quest for balance between basic and applied research led him to seek a faculty position.
Krupenkin’s research focuses on solid-liquid interaction, an area that affects many other fields, including microfluidics, biology and propulsion. “Wherever there is a liquid, it has to be in something,” says Krupenkin. “It’s interacting with some type of solid. If you can change this interaction, you can do a lot of interesting things that aren’t possible right now.”
Currently, he is using nanotechnology to make surfaces with dynamic wettability—that is, the surfaces can change how “slippery” they are. In one stage, the surface is hydrophilic, or wettable, so liquids spread out across the surface. Then, with the flip of a switch, the surfaces can be made extremely hydrophobic, or liquid-repelling, causing any liquid on the surface to bead up.
Such surfaces could have a huge effect in microfluidics—for example, in lab-on-a-chip technologies, where tiny volumes of liquids are constantly in contact with channels and chambers. The presence or absence of drag could change the properties of microfluidic systems—or alternately, in another field, could revolutionize underwater propulsion. Dynamic surfaces could even facilitate stem cell differentiation.
“This is where you can actually balance basic and applied research,” says Krupenkin. “There are a lot of things that aren’t understood yet. On the other hand, you can already develop applications.”
As a cluster hire, Krupenkin had the freedom to choose his home department. He chose mechanical engineering for several reasons. “I think I have very good relations with the people in this department. I really feel that I can contribute to the growth of this department,” he says. “So I thought, ‘Why would I search for anything else?’”
FOCUS ON NEW FACULTY:
Assistant Professor Michael R. Zinn
or most people, a robot that performs heart surgery is the stuff of science fiction. For Assistant Professor Michael Zinn, it’s reality.
Zinn’s research focuses on human-centered robotics, or robots that work closely with their human users. “I’m a big believer that the most useful applications of robots are the ones that augment human capabilities,” says Zinn. Minimally invasive robotic surgery is a classic example: It’s a very complicated system that enhances the surgeon’s abilities, yet is completely dependent on the surgeon’s knowledge and skill.
Such complex robotic systems require machines that not only receive and follow commands from the user, but also provide constant feedback. A surgeon, for example, should have not only a visual display of the operation in progress, but also should have a sense of “touch,” or the robot’s reflection of measured and virtual forces as the instruments navigate body tissues. Such feedback falls under the field of haptics, another of Zinn’s specialties. “The ideal is that you don’t know you’re holding onto a device,” says Zinn. “It’s an immersive experience.”
Zinn joined the mechanical engineering faculty in fall 2007 after four years as the director of systems and control at Hansen Medical, a biotechnology start-up company where he helped to design and build a robotic catheter system for cardiac surgery. The surgeon uses a three-dimensional force-reflecting mouse to guide a long, flexible tube through the heart to treat a condition called atrial fibrillation.
Zinn hopes to continue pursuing the research topics he developed at Hansen Medical. “The advantage to me is that I’ve spent the last four years doing cutting-edge research, and I can build on that, both on the development side and the conceptual side,” he says.
Since robotics is a field that touches on mechanical design, electrical design, software, controls, and systems theory, Zinn’s research compliments that of many other UW-Madison faculty—particularly Associate Professor Nicola Ferrier, who specializes in visual control of robots. Zinn hopes to explore collaborative research opportunities, since the interdisciplinary nature of robotics is what first drew him to the field.
“I’m kind of a roboticist in the complete sense in that I’m very interested in the component-level technology, like the sensors and the mechanical design, but I’m equally interested in how it all fits together and how to make the system perform as best as it can,” Zinn says.