Friday, September 14, 2012

Brown School of Engineering to Host Open House for Prospective Students

The Brown University School of Engineering will hold an open house on Saturday, September 29, from 1:00 p.m. – 4:00 p.m. in room 166 of the Barus and Holley building (184 Hope Street / Corner of Hope and George Streets). The faculty of the School of Engineering and the Office of College Admission invite prospective applicants, parents, teachers, and guidance counselors to attend this open house.

The program will include an overview of the undergraduate programs of study, information about faculty and student research interests, opportunity to meet faculty and undergraduates from the School of Engineering, and a brief overview of admissions and financial aid.

Students are asked to please RSVP online by Monday, September 24. Students may call (401) 863-7930 for further information.

The Brown undergraduate engineering program enrolls 400 students, and is the oldest in the Ivy League and the third oldest civilian program in the nation.  Students may earn a bachelor of science degree in one of six ABET accredited programs: biomedical engineering, chemical and biochemical engineering, computer engineering, electrical engineering, materials engineering, or mechanical engineering.

For any students arriving on campus early, the admission office offers regularly scheduled information sessions at 10:00 a.m. and 11:00 a.m. and campus tours at 10:00 a.m., 11:00 a.m., and noon. Tours leave from the Stephen Robert ’62 Campus Center located at 75 Waterman Street.

Wednesday, September 5, 2012

Meet the New Faculty: Jacob Rosenstein

Biological sensors that detect currents at the nanoscale would have important clinical applications, but how to separate signal from noise when the current lasts for 10 microseconds? Jacob Rosenstein has theories and devices that enable measurement at small timescales.

Jacob Rosenstein enjoyed his undergraduate years at Brown and certainly made the most of them. He graduated magna cum laude and co-founded a company with Anubhav Tripathi, associate professor of engineering. Still, when Rosenstein graduated in 2005, continuing in academia was far from his mind.

Jacob Rosenstein
Assistant Professor of Engineering
Credit: Mike Cohea/Brown University
But seven years later, following a stint in the semiconductor industry and now all but finished with a Ph.D. from Columbia University, he’s set to return to Brown for a job as an assistant professor of engineering. Much as he did while a Brown student, he plans to continue innovating at the nexus of electronics and biology.

“Integrated circuits are all around us, but historically most of the industry focus has been toward computing and communications,” says Rosenstein. “I’m excited to see what we can do to leverage all of that advanced technology for biological and chemical sensors.”

Rosenstein was a busy senior at Brown. At the same time he was developing a new microphone array platform with Harvey Silverman, professor of engineering, he was also working with Tripathi to develop instruments for microfluidic chips, which are integrated circuits that control the flow of fluids rather than electrical current. They founded Gauge Microfluidics in Providence to commercialize the work.

With a resumé of academic brilliance and entrepreneurship, it didn’t take long for Rosenstein to find an industry job. Shortly after graduation, he moved to Boston to join Analog Devices, a major player in the semiconductor business. He worked in the company’s wireless division, helping to develop and test application-specific integrated circuits and working on prototype cell phone designs.

Rosenstein worked at Analog for more than two years before his whole business unit was sold to the Taiwanese company MediaTek. He was still happy there, but he had begun to do some professional soul searching. The desire to gain more experience in chip design led him back to the notion of graduate school. He enrolled at Columbia in 2008.

In the Bioelectronic Systems Lab of Kenneth Shepard at Columbia, Rosenstein returned to the practice of bringing silicon technology to bear on biophysical systems. At Columbia, his main project has been the design of an integrated circuit amplifier to improve measurements of weak ionic currents. Cell membranes contain a variety of proteins which regulate the movement of dissolved ions in and out of the cell, and the movement of these ions can be measured as an electrical current. However, in many cases this current is very small, making it difficult to measure the signal above the noise. Rosenstein’s amplifier reduces the noise level at high frequencies, considerably improving the quality of fast ion channel recordings.

“As you get down to the range of 10 microseconds or less it gets very difficult to measure that weak current,” he said. “Where I’ve come in is to make new electronics and experimental setups to reduce the noise level and therefore enable measurements at timescales that people have not been able to measure.”

Researchers have been also able to make biosensors inspired by ion channels using very tiny holes called “nanopores.” If its diameter is not much larger than a single molecule, a nanopore can yield a change in its ionic current when a molecule such as DNA passes through the pore. However, these weak signals are usually very brief, making them difficult to measure. In a paper earlier this year in Nature Methods, Rosenstein demonstrated that signals as fast as 1 microsecond can be recorded from individual DNA molecules when a nanopore is integrated with his custom amplifier.

Now back at Brown, Rosenstein is looking forward to exploring other opportunities in bioelectronics. He said the University’s success in harnessing signals directly from neurons in the brain with the BrainGate sensor is a particularly inspiring example.

“There are a lot of other interesting diagnostics, sensors, and hybrid systems that are mostly unexplored,” he said. “I’m very excited to test the waters and get to know the pure sciences and life sciences groups at Brown, and hopefully I can be a hub of instrumentation, sensing, and high-performance electronics.”

Rosenstein returns with an established track record of exactly that.

- David Orenstein/Brown University

Meet the New Faculty: Haneesh Kesari

Understanding a small sea sponge and its ability to anchor itself to the ocean floor, Haneesh Kesari hopes, will point the way to stronger, lighter, better man-made materials.

As an engineer, Haneesh Kesari takes his inspiration from nature.

The new assistant professor of engineering marvels at how nature takes a few proteins and a bit of calcium or silica and creates structures with amazing material properties — emergent properties that might seem impossible given limited raw ingredients.

Haneesh Kesari
Assistant Professor of Engineering
Credit: Frank Mullin/Brown University
“Nature is doing it,” he says, “hence it is possible. How to do it is what my research will be focused on.”

Kesari is currently studying Euplectella, a genus of sea sponges. Sea creatures might seem strange territory for a materials scientist, but Euplectella have peculiarities that make them something of an engineering marvel. Whereas most animal species form their skeletons with calcium, Euplectella are made mostly of silica—glass. But don’t think of these creatures as the fragile Ming vases of the sea. On the contrary, their skeletons are strikingly robust.

Kesari is interested specifically in the root-like appendages that fix the animals to the ocean floor. The glassy structures, called basalia spicules, have properties similar to man-made fiber optic cable, only the sponge-made versions are substantially stronger and more flexible. Imaging these appendages at the nanoscale reveals an intricate construction. Each spicule is made of concentric layers, some made of glass, others made of a polymer. It’s the pattern in which these layers are arranged that caught Kesari’s attention.

“You see it and think, ‘Is this really an animal skeleton or is it a figure from a math book?’” he said. “It had an algorithmic beauty to it. We didn’t know what the algorithm was, but felt that there had to be one, because it had such regularity to it.”

Kesari thought this pattern might contribute to the spicules’ renowned strength, so he set to work calculating what pattern of layers would be the strongest given the materials in the spicule. “We calculated it and it so happens the resulting algorithm matches very well with what we see in the spicule,” he said.

Amazing what nature can accomplish given enough time.

Understanding these sorts of mathematical regularities in nature could lead to the man-made materials of the future. It’s a slow and difficult process, Kesari says, but Brown is the perfect place for that sort of research. There’s a culture in the School of Engineering that “encourages the pursuit of rigor and thoroughness, and rewards originality and creativity,” he says. “It’s nice to see the traditional quality of science — the main reason why many of us chose to do science in the first place — is retained here.”

Not to mention, he adds, that Brown is known for employing many of the “rock stars” in the field of solid mechanics over the years.

Aside from his work on Euplectella, Kesari has worked extensively on understanding adhesive properties and surface roughness, including a theoretical basis for why things like sticky notes and packing tape stick better when you push them down harder. He also studies failure patterns in polymer-based materials.

Kesari earned his Ph.D. from Stanford in 2011. He grew up in southern India, where his fascination with engineering started.

“My father worked in irrigation,” he said. “One of the early experiences I had was going to these small irrigation canals to play. The entire community revolved around water for crops and everything else, and I could see how just having a simple stone structure changed people’s lives so dramatically.”

He came to view engineering as humanity’s way of putting our collective foot down, no longer helpless against the blind whims of droughts and floods.

“Engineering, it seems to me, is a very special enterprise,” he said. Through it “we control our own destiny.”

- Kevin Stacey/Brown University

Tuesday, September 4, 2012

Meet the Faculty: Jennifer Franck

Passenger jet or flapping bat, Jennifer Frank writes code that simulates the flow of air around things with wings. The computational approach has advantages and efficiencies, especially for someone to whom coding comes naturally.

Jennifer Franck’s first foray into computing was on the venerable, if rudimentary, Commodore 64. As a child, she tapped out simple looping programs that sent a series of numbers to her printer. Since those early days, Franck’s programs have gotten considerably more complex.

Jennifer Franck
Lecturer in Engineering
Credit: Mike Cohea/Brown University
The new lecturer in engineering is an expert in computational fluid dynamics. She writes programs that simulate how fluids and gases flow around objects. Specifically, she codes what are called large-eddy simulations, a class of code designed to study turbulence. She mostly uses her model to investigate the dynamics of flight — how wind interacts with wings.

After earning her Ph.D. in mechanical engineering from Caltech in 2009, she came to Brown as a postdoc to work with Kenneth Breuer in engineering and Sharon Swartz in ecology and evolutionary biology, who are widely known for their research on the mechanics of bat flight. “What I was interested in was to see if I could explain some of the characteristics of animal flight using my models on the computer,” Franck said.

One of the questions Franck looked at is why bats flap their wings, as opposed to using them for soaring flight. “There’s a theory that bats evolved from passive gliders to actively flapping their wings,” she said. “The question was, what’s the benefit of flapping.”

Franck’s models helped to show that flapping creates vortices — tiny pockets of low air pressure — above a bat’s wings. Those vortices create extra lift and may be part of the reason flapping is worth the effort.

Franck has also used her models to explore applications that might improve aircraft flight. “Say you want an airplane to have more lift,” she said. “Could you apply some sort of device on the wing that would pump some extra energy into the flow and give you better performance? I’m interested in applying code to those types of flow control questions.”

There are significant advantages to the computational approach, Franck says. It’s much easier, for example, to modify the parameters of an experiment on a computer than it is to design new physical models for wind tunnel tests. Another advantage is that computer models help to isolate the specific aspects of a problem that researchers are trying to address.

“We generally model a very simple airfoil that’s often just two dimensional because it simplifies the problem,” Franck said. “If we’re looking at the basic physics behind a problem, we don’t want to make things too complicated.”

Though the models may be simple, the code that generates them is not. Most of Franck’s programs require computer clusters that string together multiple processors. For some of her research, Franck has used a cluster at Brown’s Center for Computation and Visualization. For other projects she’s used the Department of Defense’s Army Research Lab cluster in Maryland.

It’s a long way from the Commodore 64, but Franck is right at home. “Coding has always just come naturally to me,” she says.

She and her husband Christian, professor of engineering at Brown, live in Providence with their two kids.

- Kevin Stacey/Brown University

Meet the Faculty: Indrek Külaots

Graphene — sheets of carbon that are one atom thick — could help take mercury and other nasty pollutants out of circulation if only there were a way to keep the sheets from sticking together. Indrek Külaots is working on a system of nanoscale pillars.

Indrek Külaots is using garbage to make the world a cleaner place.

Indrek Külaots
Lecturer in Engineering
Credit: Frank Mullin/Brown University
Untold tons of plant matter are discarded in the United States every day. Much of this biomass — farm waste, sawdust, wood scraps, household yard waste — is trucked off to landfills. As it rots, it produces carbon dioxide and methane, greenhouse gases that contribute to global warming.

“My research focuses on trying to make better use of this bio-waste material,” said Külaots, lecturer in engineering. He has found a way to turn this trash into sorbent material than can sop up industrial pollutants.

Using a simple technique called pyrolysis — the same process used to make charcoal — plant waste can be broken down into what’s called bio-char. “This char product has relatively high surface area and is also highly porous,” Külaots said. “We can use those pores as workers for pollutant capture.”

He has patented a method of using modified bio-char to absorb elemental mercury. Bio-char could one day be used as a cost-effective way to scrub mercury from power plant vapor emissions, replacing expensive activated carbon filters. Bio-char sorbents also show promise for cleaning up other pollutants like arsenic, cadmium, and lead, Külaots says.

Külaots’ interest in environmental engineering began in his native Estonia. After earning his master’s degree in mechanical engineering at the Tallinn Technical University, he worked on a project to recycle fly ash, a byproduct produced by the burning of oil shale. His work on that subject caught the eye of Eric Suuberg, an engineering professor at Brown. Suuberg thought Külaots’ work could be applied to fly ash created by the burning of coal, which is a major concern in the United States

“He saw my work and said, ‘Why don’t you apply?’” Külaots said. “So I came to Brown as a Ph.D. student and I never left.”

After earning a master’s degree in applied mathematics in 2000 and a Ph.D. in chemical engineering in 2001, Külaots stayed at Brown as a senior research engineer. In 2009, he was awarded a joint position as lecturer and research engineer. This year he joins the faculty as a lecturer.

In addition to teaching classes in chemical, mechanical, and environmental engineering, he’s expanding his research program to include a hot topic in the material sciences world: graphene.

Graphene is a one-atom-thick sheet of carbon, with vast surface area. It began getting notoriety a few years ago and quickly gained a reputation as a miracle material. Its electrical properties make it a likely successor of silicon in microprocessors. It also holds promise as a way to store gases like hydrogen for use in fuel cells, and it can catalyze chemical reactions.

But for all its miraculousness, graphene has a problem. The sheets have a tendency to get stuck together in stacks when processed, which decreases this vast surface area on each sheet. Think of two sheets of paper stapled at all four corners. It’s not possible to write on the back of the first page or the front of the second because those surfaces are stuck together.

“My research is how to interrupt this stacking,” Külaots said. “How can we get something in the middle so we can actually use the inner layer space as well?”

He’s developing tiny carbon columns to do the job.

“It’s just a pillar, like in ancient Rome,” he said. “But when you’re working at the nanoscale it’s not that easy.” Despite the difficulty, Külaots has had success using his pillars to recover some of this lost space, and recently presented his work at one of the world’s top conferences on carbon materials.

“These pillared graphene and graphene oxide systems have a great potential in the fields of gas storage, separation, and catalysis, if properly converted into bulk materials,” he said.

Such is the fast-paced world of engineering: Even before graphene makes it out of the lab and into production, Külaots is thinking of ways to make it better.

Kevin Stacey/Brown University