BRAINGATE - Brown University

EngineeringSchool of

MagazineSummer 2012

BRAINGATE

BROWN

Using robotic arms controlled directly with brain activity

Biochip measures glucose in saliva, eliminates the need to draw blood

Professor Huajian Gao elected to National Academy of Engineering

Brown President-Elect Christina Paxson visits with professors and students

Professor Barrett Hazeltine named one of “Best 300 Professors” in the country

BROWN SchOOl Of ENgiNEERiNg 4

I N S I D E T H I S I S S U E

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Message from the Dean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

People with paralysis control robotic arms using brain-computer interface . . . . . . . . . 2

Biochip measures gluscose in saliva, not blood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Single nanomaterial yields many laser colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Bats save energy by drawing in wings on upstroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Nanowrinkles, nanofolds yield strange hidden channels . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Novel device removes heavy metals from water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Senator Reed, federal and state officials tour Brown’s Superfund Lab . . . . . . . . . . . . . . 14

Faculty Awards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Brown University President-Elect Paxson visits School of Enginering . . . . . . . . . . . . . . . 18

Barrett Hazeltine named one of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19America’s “Best 300 Professors” by Princeton Review

Brown Engineering in Moscow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Hear me Now? Computers can now recognize individual speakers . . . . . . . . . . . . . . . . 22

Brown’s Engineers Without Borders working in the Dominican Republic . . . . . . . . . . . . 23

Advisory Council / Alumni Involvement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

School of Engineering Magazine

EditorialGordon Morton ’93Manager of Communications, School of Engineering

DesignAmy Simmons

PhotographyGordon Morton ’93, Mike Cohea, Frank Mullin,Lauren Brennan, Dingyi Sun ’12, Alex Grosvenor ’12

Printed in the USA

Letter from the Editor:

In our last issue, we brought you the story of four women – Amanda Kautz ’12, Natalie Ser-rino ’12, Farzanah Ausaluth ’14 and Lizzie Costa ’14 - who were inspired to start SPIRA, a free four-week summer engineering camp for rising tenth grade girls. Last summer the camp was funded through a grant from the National Sci-ence Foundation (NSF) through Brown’s Mate-rials Research Science and Engineering Center (MRSEC).

This year, the program was without funding – until an alumnus saw the SPIRA story in the School of Engineering Magazine and offered to help. Mike Strem ’58 P’97, founder and president of Strem Chemicals, stepped up with a generous gift of $22,000 to fund the program for the upcoming year. Kautz and Serrino were also honored at Com-mencement with the George H. Main ’45 Award.

This issue is equally inspiring – from the cover story on BrainGate to the biochip that measures glucose in saliva, Brown engineers are working to solve real problems that impact millions of people.

Our students are doing their part as well to con-tribute. Our Engineers Without Borders group has offered their skills and expertise – both in Providence and in the Dominican Republic (page 26). As they travel to the Dominican Re-public to assist the local community, they need our support. If you would like to help with this project, or other engineering fundraising ef-forts, please contact Rick Marshall ([email protected] or 401-863-9877) in the Brown Advancement Office.

We look forward to bringing you more of these exciting and inspirational stories throughout the year, so please stay in contact with us on-line – on Twitter, Facebook, LinkedIn, YouTube, ITunes, Flickr, blogs, or the web – whatever your preferred method of communication, Brown Engineering is there.

Gordon Morton ’93Editor and Publisher

Mike Strem

1 SUMMER 2012

M E S S a g E f r o M T H E D E a N

Lawrence LarsonWhy Engineering at Brown?

Brown University’s School of Engineering educates future leaders in the fundamentals of engineering in an environment of world-class research. We stress an interdisciplinary approach and a broad understanding of underlying global issues. Collaborations across the campus and beyond strengthen our development of technological advances that address challenges of vital importance to us all.

As I finish off my first year at Brown, I re-flect on the trajectory that engineering has taken since it became a true School of En-gineering in July 2010. These last two years have been incredibly exciting, and we are just beginning the journey toward a rein-vigorated engineering program at Brown.

Under the inspiring leadership of my pre-decessor Dean Rod Clifton, the School took off like a rocket; we hired four new faculty in 2010-2011, we had significant fundrais-ing success and we began the planning for expanded graduate and undergraduate programs. Since I arrived in July of 2011, we have raised an additional $20M toward new programs and a new building for en-gineering, hired two additional faculty, significantly expanded our master’s enroll-ment, and under the leadership of Associ-ate Dean Kenny Breuer we are developing exciting new engineering courses that will be available to the entire campus commu-nity. Even greater developments for engi-neering here at Brown are just around the corner.

I also want to help the broader community understand that engineering at Brown is a unique and deep intellectual experience, designed for ambitious and broad think-ers who want to make a difference in the world. I’ve been an engineer for over thirty years, and I honestly can’t imagine doing anything else. “Engineers create the future”

is a well-known saying, and what could be more fun and fulfilling than that? I wonder: why isn’t everyone an engineer?

An engineering degree is not a narrowing of possibilities; instead,

it gives our students the opportunity to take the superb analytical skills

they acquire here, and head in many different directions.

One of the areas we have focused on in the last year is improved mentoring of our stu-dents at all levels. Almost every student in engineering faces a crisis at some point in their studies. Engineering has a lot of chal-lenging required courses that leaves less room than is desirable for the wide rang-ing intellectual exploration that students come to Brown for. How is a young person supposed to figure out areas of interest and, yes, passion if there is limited freedom to explore? Many students get discouraged by all the requirements.

The good news for Brown students is that the engineering curriculum here is more flexible than that at most other universi-ties. In fact, the opportunity to explore a wide range of subjects is built into our curriculum. We have plans in place for stu-dents who might not start engineering until sophomore year, allowing for wider exploration as a first-year. Finally, if there’s an interest to explore even further outside of the traditional engineering curriculum, an AB in engineering is an option for all of our students.

The actual practice of engineering can be utterly thrilling. In my own field of electrical and computer engineering, there are many beautiful intellectual constructs - like Max-well’s Equations, Shannon’s Coding Theo-rems, and modern solid-state physics - that are so simple and elegant, and yet have a profound impact on our everyday lives. Ev-ery branch of engineering has similar fun-damental results, whose creative applica-tion touches the lives of every person in the modern world. Engineering is not just for the math or science genius; it is a field most open to intensely curious learners who strive to work hard, create new innovations and make a difference in the world. Brown is the perfect place for the engineer who wants to explore the broader intellectual feast that our curriculum provides.


f r o M T H E L a B S

A new study in Nature reports that two people with tetraplegia were able to reach for and grasp objects in

three-dimensional space using robotic arms that they controlled directly with brain activity. They used the

BrainGate neural interface system, an investigational device currently being studied under an Investigational

Device Exemption. One participant used the system to serve herself coffee for the first time since becoming

paralyzed nearly 15 years ago.

On April 12, 2011, nearly 15 years after she be-came paralyzed and unable to speak, a woman controlled a robotic arm by thinking about moving her arm and hand to lift a bottle of cof-fee to her mouth and take a drink. That achieve-ment is one of the advances in brain-computer interfaces, restorative neurotechnology, and assistive robot technology described in the May 17 edition of the journal Nature by the BrainGate2 collaboration of researchers at the Department of Veterans Affairs, Brown Univer-sity, Massachusetts General Hospital, Harvard Medical School, and the German Aerospace Center (DLR).

A 58-year-old woman (“S3”) and a 66-year-old man (“T2”) participated in the study. They had each been paralyzed by a brainstem stroke years earlier which left them with no functional control of their limbs. In the research, the par-ticipants used neural activity to directly control two different robotic arms, one developed by the DLR Institute of Robotics and Mechatronics and the other by DEKA Research and Develop-ment Corp., to perform reaching and grasping tasks across a broad three-dimensional space. The BrainGate2 pilot clinical trial employs the investigational BrainGate system initially de-veloped at Brown University, in which a baby aspirin-sized device with a grid of 96 tiny elec-trodes is implanted in the motor cortex — a part of the brain that is involved in voluntary movement. The electrodes are close enough to individual neurons to record the neural ac-tivity associated with intended movement. An external computer translates the pattern of impulses across a population of neurons into commands to operate assistive devices, such as the DLR and DEKA robot arms used in the study now reported in Nature.

BrainGate participants have previously dem-onstrated neurally based two-dimensional

point-and-click control of a cursor on a com-puter screen and rudimentary control of simple robotic devices.

The study represents the first demonstration and the first peer-reviewed report of people with tetraplegia using brain signals to control a robotic arm in three-dimensional space to complete a task usually performed by their arm. Specifically, S3 and T2 controlled the arms to reach for and grasp foam targets that were placed in front of them using flexible supports. In addition, S3 used the DLR robot to pick up a bottle of coffee, bring it to her mouth, issue a command to tip it, drink through a straw, and return the bottle to the table. Her BrainGate-en-abled, robotic-arm control during the drinking task required a combination of two-dimension-al movements across a table top plus a “grasp” command to either grasp and lift or tilt the ro-botic hand.

“Our goal in this research is to develop technol-ogy that will restore independence and mobil-ity for people with paralysis or limb loss,” said lead author Dr. Leigh Hochberg, a neuroengi-neer and critical care neurologist who holds appointments at the Department of Veterans Affairs, Brown University, Massachusetts Gen-eral Hospital, and Harvard. He is the sponsor-investigator for the BrainGate2 pilot clinical trial. “We have much more work to do, but the encouraging progress of this research is dem-onstrated not only in the reach-and-grasp data, but even more so in S3’s smile when she served herself coffee of her own volition for the first time in almost 15 years.”

Partial funding for this work comes from the VA, which is committed to improving the lives of injured veterans. “VA is honored to have played a role in this exciting and promising area of re-search,” said VA Secretary Eric Shinseki. “Today’s announcement represents a great step forward

toward improving the quality of life for veterans and others who have either lost limbs or are paralyzed.”

Hochberg adds that even after nearly 15 years, a part of the brain essentially “disconnected” from its original target by a brainstem stroke was still able to direct the complex, multidi-mensional movement of an external arm — in this case, a robotic limb. The researchers also noted that S3 was able to perform the tasks more than five years after the investigational BrainGate electrode array was implanted. This sets a new benchmark for how long implanted brain-computer interface electrodes have re-mained viable and provided useful command signals.

John Donoghue, the VA and Brown neurosci-entist who pioneered BrainGate more than a decade ago and who is co-senior author of the study, said the paper shows how far the field of brain-computer interfaces has come since the

People with paralysis control robotic arms using brain-computer interface

Leigh Hochberg

The investigational BrainGate neural interface array detects and record brain signals, and has allowing persons who have lost the use of their arms to have point-and-click control of a com-pute, and to control external devices such as a robotic or prosthetic arm. A BrainGate device has provided useful signals for more than five years-Credit: Matthew McKee/BrainGate Collaboration

3 SUMMER 2012


first demonstrations of computer control with BrainGate.

“This paper reports an important advance by rigorously demonstrating in more than one participant that precise three-dimensional neural control of robot arms is not only pos-sible, but also repeatable,” said Donoghue, who directs the Brown Institute for Brain Science. “We’ve moved significantly closer to returning everyday functions, like serving yourself a sip of coffee, usually performed effortlessly by the arm and hand, for people who are unable to move their own limbs. We are also encouraged to see useful control more than five years after implant of the BrainGate array in one of our participants. This work is a critical step toward realizing the long-term goal of creating a neu-rotechnology that will restore movement, con-trol, and independence to people with paralysis or limb loss.”

In the research, the robots acted as a substitute for each participant’s paralyzed arm. The robot-ic arms responded to the participants’ intent to move as they imagined reaching for each foam target. The robot hand grasped the target when the participants imagined a hand squeeze. Because the diameter of the targets was more than half the width of the robot hand openings, the task required the participants to exert pre-cise control. (Videos of these actions are avail-able on the Nature website.)

In 158 trials over four days, S3 was able to touch the target within an allotted time in 48.8 per-cent of the cases using the DLR robotic arm and hand and 69.2 percent of the cases with the DEKA arm and hand, which has the wider grasp. In 45 trials using the DEKA arm, T2 touched the target 95.6 percent of the time. Of the success-ful touches, S3 grasped the target 43.6 percent of the time with the DLR arm and 66.7 percent of the time with the DEKA arm. T2’s grasp suc-ceeded 62.2 percent of the time.

T2 performed the session in this study on his fourth day of interacting with the arm; the prior three sessions were focused on system devel-opment. Using his eyes to indicate each letter, he later described his control of the arm: “I just imagined moving my own arm and the [DEKA] arm moved where I wanted it to go.”

The study used two advanced robotic arms: the DLR Light-Weight Robot III with DLR five-

fingered hand and the DEKA Arm System. The DLR LWR-III, which is designed to assist in recre-ating actions like the human arm and hand and to interact with human users, could be valuable as an assistive robotic device for people with various disabilities. Patrick van der Smagt, head of bionics and assistive robotics at DLR, direc-tor of biomimetic robotics and machine learn-ing labs at DLR and the Technische Universität München, and a co-senior author on the paper said: “This is what we were hoping for with this arm. We wanted to create an arm that could be used intuitively by varying forms of control. The arm is already in use by numerous research labs around the world who use its unique interac-tion and safety capabilities. This is a compelling demonstration of the potential utility of the arm by a person with paralysis.”

DEKA Research and Development developed the DEKA Arm System for amputees, through funding from the United States Defense Ad-vanced Research Projects Agency (DARPA). Dean Kamen, founder of DEKA said, “One of our dreams for the Luke Arm [as the DEKA Arm Sys-tem is known informally] since its inception has been to provide a limb that could be operated not only by external sensors, but also by more directly thought-driven control. We’re pleased about these results and for the continued re-search being done by the group at the VA, Brown and MGH.” The research is aimed at learning how the DEKA arm might be controlled directly

from the brain, potentially allowing amputees to more naturally control this prosthetic limb.

Over the last two years, VA has been conducting an optimization study of the DEKA prosthetic arm at several sites, with the cooperation of veterans and active duty service members who have lost an arm. Feedback from the study is helping DEKA engineers to refine the artificial arm’s design and function. “Brain-computer in-terfaces, such as BrainGate, have the potential to provide an unprecedented level of function-al control over prosthetic arms of the future,” said Joel Kupersmith, M.D., VA chief research and development officer. “This innovation is an example of federal collaboration at its finest.”

Story Landis, director of the National Institute of Neurological Disorders and Stroke, which fund-ed the work in part, noted: “This technology was made possible by decades of investment and research into how the brain controls move-ment. It’s been thrilling to see the technology evolve from studies of basic neurophysiology and move into clinical trials, where it is showing significant promise for people with brain inju-ries and disorders.”

In addition to Hochberg, Donoghue, and van der Smagt, other authors on the paper are Dan-iel Bacher, Beata Jarosiewicz, Nicolas Masse, John Simeral, Joern Vogel, Sami Haddadin, Jie Liu, and Sydney Cash.

By David Orenstein

One small step. A 58-year-old woman, paralyzed by a stroke for almost 15 years, uses her thoughts to control a robotic arm, grasp a bottle of coffee, serve herself a drink, and return the bottle to the table.


For the 26 million Americans with diabetes, drawing blood is the most prevalent way to check glucose levels. It is invasive and at least minimally painful. Researchers at Brown Uni-versity are working on a new sensor that can check blood sugar levels by measuring glu-cose concentrations in saliva instead.

The technique takes advantage of a conver-gence of nanotechnology and surface plas-monics, which explores the interaction of electrons and photons (light). The engineers at Brown etched thousands of plasmonic in-terferometers onto a fingernail-size biochip and measured the concentration of glucose molecules in water on the chip. Their results showed that the specially designed biochip could detect glucose levels similar to the lev-els found in human saliva. Glucose in human saliva is typically about 100 times less con-centrated than in the blood.

“This is proof of concept that plasmonic in-terferometers can be used to detect mol-ecules in low concentrations, using a foot-print that is ten times smaller than a human hair,” said Domenico Pacifici, assistant pro-fessor of engineering and lead author of the paper published in Nano Letters, a journal of the American Chemical Society.

The technique can be used to detect other chemicals or substances, from anthrax to biological compounds, Pacifici said, “and to detect them all at once, in parallel, using the same chip.”

To create the sensor, the researchers carved a slit about 100 nanometers wide and etched two 200 nanometer-wide grooves

on either side of the slit. The slit captures incoming photons and confines them. The grooves, meanwhile, scatter the incoming photons, which interact with the free elec-trons bounding around on the sensor’s met-al surface. Those free electron-photon inter-actions create a surface plasmon polariton, a special wave with a wavelength that is nar-rower than a photon in free space. These sur-

face plasmon waves move along the sensor’s surface until they encounter the photons in the slit, much like two ocean waves coming from different directions and colliding with each other. This “interference” between the two waves determines maxima and minima in the light intensity transmitted through the slit. The presence of an analyte (the chemi-cal being measured) on the sensor surface generates a change in the relative phase dif-ference between the two surface plasmon waves, which in turns causes a change in

light intensity, measured by the researchers in real time.

“The slit is acting as a mixer for the three beams — the incident light and the surface plasmon waves,” Pacifici said.

The engineers learned they could vary the phase shift for an interferometer by chang-ing the distance between the grooves and the slit, meaning they could tune the in-terference generated by the waves. The researchers could tune the thousands of in-terferometers to establish baselines, which could then be used to accurately measure concentrations of glucose in water as low as 0.36 milligrams per deciliter.

The engineers next plan to build sensors tai-lored for glucose and for other substances to further test the devices. “The proposed ap-proach will enable very high throughput de-tection of environmentally and biologically relevant analytes in an extremely compact design. We can do it with a sensitivity that ri-vals modern technologies,” Pacifici said.

Tayhas Palmore, professor of engineering, is a contributing author on the paper. Gradu-ate students Jing Feng (engineering) and Vince Siu (bioengineering), who designed the microfluidic channels and carried out the experiments, are listed as the first two authors on the paper. Other authors include Brown engineering graduate student Steve Rhieu and undergraduates Vihang Mehta, Alec Roelke.

The National Science Foundation and Brown (through a Richard B. Salomon Faculty Re-search Award) funded the research.

“It could be possible to use these biochips to carry out the screening

of multiple biomarkers for individual patients, all at once and

in parallel, with unprecedented sensitivity,” Pacifici said.

Engineers at Brown University have designed a biological device that can measure glucose

concentrations in human saliva. The technique could eliminate the need for diabetics to draw

blood to check their glucose levels. The biochip uses plasmonic interferometers and could be

used to measure a range of biological and environmental substances.


By Richard Lewis

Domenico Pacifici

Biochip measures glucose in saliva, not blood

5 SUMMER 2012

BiochipLCD Panel

Indicator LightControl Button

LCD Camera

Battery

Tripping the light fantastic. Each plasmonic interferometer -thousands of them per square millimeter - consists of a slit flanked by two grooves etched in a silver metal film. The schematic shows glucose molecules “dancing” on the sensor surface illumniated by light with different colors. Changes in light intensity transmitted through the slit of each plasmonic interferometer yield information about the concentration of glucose molecules in solution.Credit: Domenico Pacifici

Above: Sketch of prototype employing Surface Plasmon Interferometric Technology for non-Invasive glucose Testing (SPIT’nIT).

Right: Top view image of a portable glucose sensor prototype showing the lab-on-a-chip gold layer containing thousands of plasmonic interferometers, coupled to a CMOS sensor.


Red, green, and blue lasers have become small and cheap enough to find their way into products ranging from BluRay DVD players to fancy pens, but each color is made with different semiconductor materials and by elaborate crystal growth processes. A new prototype technology demonstrates all three of those colors coming from one material. That could open the door to mak-ing products, such as high-performance digital displays, that employ a variety of la-ser colors all at once.

“Today in order to create a laser display with arbitrary colors, from white to shades of pink or teal, you’d need these three separate ma-terial systems to come together in the form of three distinct lasers that in no way shape or form would have anything in common,” said Arto Nurmikko, professor of engineer-ing at Brown University and senior author of a paper describing the innovation in the journal Nature Nanotechnology. “Now enter a class of materials called semiconductor quantum dots.”

The materials in prototype lasers described in the paper are nanometer-sized semicon-ductor particles called colloidal quantum dots or nanocrystals with an inner core of cadmium and selenium alloy and a coating of zinc, cadmium, and sulfur alloy and a pro-prietary organic molecular glue. Chemists at QD Vision of Lexington, Mass., synthesize the nanocrystals using a wet chemistry pro-cess that allows them to precisely vary the nanocrystal size by varying the production time. Size is all that needs to change to pro-duce different laser light colors: 4.2 nano-meter cores produce red light, 3.2 nanome-ter ones emit green light and 2.5 nanometer

Engineers at Brown University and QD Vision Inc. have created nanoscale single crystals that

can produce the red, green, or blue laser light needed in digital displays. The size determines

color, but all the pyramid-shaped quantum dots are made the same way of the same elements.

In experiments, light amplification required much less power than previous attempts at the

technology. The team’s prototypes are the first lasers of their kind.

ones shine blue. Different sizes would pro-duce other colors along the spectrum.

The cladding and the nanocrystal structure are critical advances beyond previous at-tempts to make lasers with colloidal quan-tum dots, said lead author Cuong Dang, a senior research associate and nanopho-tonics laboratory manager in Nurmikko’s group at Brown. Because of their improved quantum mechanical and electrical perfor-mance, he said, the coated pyramids require 10 times less pulsed energy or 1,000 times less power to produce laser light than previ-ous attempts at the technology.

Quantum nail polish

When chemists at QDVision brew a batch of colloidal quantum dots for Brown-designed specifications, Dang and Nurmikko get a vial of a viscous liquid that Nurmikko said some-what resembles nail polish. To make a laser, Dang coats a square of glass — or a variety of other shapes — with the liquid. When the liquid evaporates, what’s left on the glass are several densely packed solid, highly ordered layers of the nanocrystals. By sandwiching that glass between two specially prepared mirrors, Dang creates one of the most chal-lenging laser structures, called a vertical-cavity surface-emitting laser. The Brown-led team was the first to make a working VCSEL with colloidal quantum dots.

The nanocrystals’ outer coating alloy of zinc, cadmium, sulfur and that molecular glue is important because it reduces an excited electronic state requirement for lasing and protects the nanocrystals from a kind of crosstalk that makes it hard to produce laser light, Nurmikko said. Every batch of colloidal quantum dots has a few defective ones, but normally just a few are enough to interfere with light amplification.

Faced with a high excited electronic state requirement and destructive crosstalk in a densely packed layer, previous groups have needed to pump their dots with a lot of power to push them past a higher thresh-old for producing light amplification, a core element of any laser. Pumping them in-tensely, however, gives rise to another prob-lem: an excess of excited electronic states called excitons. When there are too many of these excitons among the quantum dots,


Single nanomaterial yields many laser colors

“We have managed to show that it’s possible to create not only

light, but laser light,” Nurmikko said. “In principle, we now have some benefits: using the same

chemistry for all colors, producing lasers in a very inexpensive way,

relatively speaking, and the ability to apply them to all kinds of

surfaces regardless of shape. That makes possible all kinds of device

configurations for the future.”

Arto Nurmikko

7 SUMMER 2012

energy that could be producing light is in-stead more likely to be lost as heat, mostly through a phenomenon known as the Au-ger process.

The nanocrystals’ structure and outer clad-ding reduces destructive crosstalk and lowers the energy needed to get the quan-tum dots to shine. That reduces the energy required to pump the quantum dot laser and significantly reduces the likelihood of exceeding the level of excitons at which the Auger process drains energy away. In addi-tion, a benefit of the new approach’s struc-ture is that the dots can act more quickly, releasing light before Auger process can get started, even in the rare cases when it still does start.

“We have managed to show that it’s possible to create not only light, but laser light,” Nur-mikko said. “In principle, we now have some benefits: using the same chemistry for all

colors, producing lasers in a very inexpen-sive way, relatively speaking, and the ability to apply them to all kinds of surfaces regard-less of shape. That makes possible all kinds of device configurations for the future.”

In addition to Nurmikko and Dang, another author at Brown is Joonhee Lee. QD Vi-sion authors include Craig Breen, Jonathan Steckel, and Seth Coe-Sullivan, a company co-founder who studied engineering at

f r o M T H E L a B

Brown as an undergraduate.

The US. Department of Energy, the Air Force Office for Scientific Research, and the Na-tional Science Foundation supported the research. Dang is a Vietnam Education Foun-dation (VEF) Scholar.

Vertical-cavity surface-emitting laserColloidal quantum dots — nanocrystals — can produce lasers of many colors. Cuong Dang manipulates a green beam that pumps the nanocrystals with energy, in this case producing red laser light. Credit: Mike Cohea/Brown University

ExcitationLaser BeamCQD-VCSEL

Long Pass Filter

Schematic of a vertically pump CQD-VCSEL with a long pass filter to remove any residual pump excitation beam. CQD gain medium is placed inside a wedge cavity for a variable cav-ity length. The wedge angle is 1.2 × 10−3 rad, and two DBRs have reflectivity higher than 99%.

By David Orenstein


Whether people are building a flying ma-chine or nature is evolving one, there is pres-sure to optimize efficiency. A new analysis by biologists, physicists, and engineers at Brown University reveals the subtle but im-portant degree to which that pressure has literally shaped the flapping wings of bats.

The team’s observations and calculations show that by flexing their wings inward to their bodies on the upstroke, bats use only 65 percent of the inertial energy they would expend if they kept their wings fully out-stretched. Unlike insects, bats have heavy, muscular wings with hand-like bendable joints. The study suggests that they use their flexibility to compensate for that mass.

“Wing mass is important and it’s normally not considered in flight,” said Attila Bergou, who along with Daniel Riskin is co-lead au-thor of the study that appears April 11 in the Proceedings of the Royal Society B. “Typi-cally you analyze lift, drag, and you don’t talk about the energy of moving the wings.”

The findings not only help explain why bats and some birds tuck in their wings on the upstroke, but could also help inform hu-man designers of small flapping vehicles. The team’s research is funded by the U.S. Air Force Office of Sponsored Research.

“If you have a vehicle that has heavy wings, it would become energetically beneficial to fold the wings on the upstroke,” said Sha-ron Swartz, professor of ecology and evolu-tionary biology at Brown. She and Kenneth Breuer, professor of engineering, are senior authors on the paper.

Bat wings are like hands: meaty, bony and full of joints. A new Brown University study finds that

bats take advantage of their flexibility by folding in their wings on the upstroke to save inertial

energy. The research suggests that engineers looking at flapping flight should account for wing

mass and consider a folding design.

The physics of flexed flapping

The team originally set out to study some-thing different: how wing motions vary among bats along a wide continuum of sizes. They published those results in 2010 in the Journal of Experimental Biology, but as they analyzed the data further, they started to consider the intriguing pattern of the in-ward flex on the upstroke.

That curiosity gave them a new perspective on their 1,000 frames-per-second videos of 27 bats performing five trials each aloft in a flight corridor or wind tunnel. They tracked markers on the bats, who hailed from six species, and measured how frequently the wings flapped, how far up and down they flapped, and the distribution of mass within them as they moved. They measured the

mass by cutting the wing of a bat that had died into 32 pieces and weighing them.

The team fed the data in to a calculus-rich model that allowed them to determine what the inertial energy costs of flapping were and what they would have been if the wings were kept outstretched.

Bergou, a physicisist, said he was surprised that the energy savings was so great, espe-cially because the calculations also showed that the bats have to spend a lot of energy — 44 percent of the total inertial cost of flap-ping — to fold their wings inward and then back outward ahead of the downstroke.

“Retracting your wings has an inertial cost,” Bergou said. “It is significant but it is out-weighed by the savings on the up and down stroke.”

The conventional wisdom has always been that bats drew their wings in on the upstroke to reduce drag in the air, and although the team did not measure that, they acknowl-edge that aerodynamics plays the bigger role in the overall energy budget of flying. But the newly measured inertial savings of drawing in the wings on the upstroke seems too significant to be an accident.

“It really is an open question whether natu-ral selection is so intense on the design and movement patterns of bats that it reaches details of how bats fold their wings,” Swartz said. “This certainly suggests that this is not a random movement pattern and that it is likely that there is an energetic benefit to animals doing this.”

Bats save energy by drawing in wings on upstroke


By David Orenstein

Kenneth Breuer

9 SUMMER 2012

f r o M T H E L a B

A computer simulation of the unsteady aerodynamics of a bat �ying at 3.4 m/s

11

23

4

Ver

tical

For

ce Inertial modelFlow model

Position

1: A Potential Flow model is used to predict the aerodynamic forces on the bat's wings.2: The accelerations of the center of gravity are used to determine the aerodynamic forces required to sustain �ight.3: The wake circulation distribution illustrates the �ow memory of the force generation during �ight.4: Complex vortex structures are present in the wake as a result of the unsteady force generation during �apping �ight.

Wingtip trace

D. J. Willissl, M. Kostandovs, D. K. Riskins, J. Perairel, D. H. Laidlaws, S. M. Swartzs & K. S. BreuerBrown University, Massachusetts Institute of Technology


f r o M T H E L a B S Kyung-Suk Kim

Wrinkles are made when a thin stiff sheet is buckled on a soft foundation or in a soft surrounding. They are precursors of regu-lar folds: When the sheet is compressed enough, the wrinkles are so closely spaced that they form folds. The folds are interest-ing to manufacturers, because they can fit a large surface area of a sheet in a finite space.

Kim and his team laid gold nanogranular film sheets ranging from 20 to 80 nanome-ters thick on a rubbery substrate commonly used in the microelectronics industry. The researchers compressed the film, creating wrinkles and examined their properties. As in previous studies, they saw primary wrin-

Nanowrinkles, nanofolds yield strange hidden channelsWrinkles and folds, common in nature, do something unusual at the nanoscale. Researchers at Brown University

and in Korea have discovered that wrinkles on super-thin films have hidden long waves. The team also found

that folds in the film produce nanochannels, like thousands of tiny subsurface pipes. The research could lead to

advances in medicine, electronics and energy. Results appear in “Proceedings of the Royal Society A”.

Wrinkles and folds are ubiquitous. They oc-cur in furrowed brows, planetary topology, the surface of the human brain, even the bottom of a gecko’s foot. In many cases, they are nature’s ingenious way of packing more surface area into a limited space. Scientists, mimicking nature, have long sought to ma-nipulate surfaces to create wrinkles and folds to make smaller, more flexible electron-ic devices, fluid-carrying nanochannels or even printable cell phones and computers.

But to attain those technology-bending feats, scientists must fully understand the profile and performance of wrinkles and folds at the nanoscale, dimensions 1/50,000th the thickness of a human hair. In a series of observations and experiments, engineers at Brown University and in Ko-rea have discovered unusual properties in wrinkles and folds at the nanoscale. The re-searchers report that wrinkles created on su-per-thin films have hidden long waves that lengthen even when the film is compressed. The team also discovered that when folds are formed in such films, closed nanochannels appear below the surface, like thousands of super-tiny pipes.

“Wrinkles are everywhere in science,” said Kyung-Suk Kim, professor of engineering at Brown and corresponding author of the paper published in the journal Proceedings of the Royal Society A. “But they hold certain secrets. With this study, we have found math-ematically how the wrinkle spacings of a thin sheet are determined on a largely deformed soft substrate and how the wrinkles evolve into regular folds.”

kles with short periodicities, the distance between individual wrinkles’ peaks or val-leys. But Kim and his colleagues discovered a second type of wrinkle, with a much longer periodicity than the primary wrinkles — like a hidden long wave. As the researchers compressed the gold nanogranular film, the primary wrinkles’ periodicity decreased, as expected. But the periodicity between the hidden long waves, which the group labeled secondary wrinkles, lengthened.

“We thought that was strange,” Kim said.

It got even stranger when the group formed folds in the gold nanogranular sheets. On the

One dimensional ordered wrinkle folding of 50nm thick gold film on a PDMS substrate. From bottom up, initially.

11 SUMMER 2012

f r o M T H E L a B

Nano hairs of water strider X. Gao and L. Jiang, Nature 432, 36 (4 November 2004)

surface, everything appeared normal. The folds were created as the peaks of neighbor-ing wrinkles got so close that they touched. But the research team calculated that those folds, if elongated, did not match the length of the film before it had been compressed. A piece of the original film surface was not accounted for, “as if it had been buried,” Kim said.

Indeed, it had been, as nano-size closed channels. Previous researchers, using atomic force microscopy that scans the film’s sur-face, had been unable to see the buried channels. Kim’s group turned to focused ion beams to extract a cross-section of the film. There, below the surface, were rows of closed channels, about 50 to a few 100 nano-meters in diameter. “They were hidden,” Kim said. “We were the first ones to cut (the film) and see that there are channels underneath.”

The enclosed nano channels are important because they could be used to funnel liq-uids, from drugs on patches to treat diseases or infections, to clean water and energy har-vesting, like a microscopic hydraulic pump.

Contributing authors include Jeong-Yun Sun and Kyu Hwan Oh from Seoul National University; Myoung-Woon Moon from the Korea Institute of Science and Technology; and Shuman Xia, a researcher at Brown and now at the Georgia Institute of Technology. The National Science Foundation, the Korea Institute of Science and Technology, the Min-istry of Knowledge Economy of Korea, and the Ministry of Education, Science, and Tech-nology of Korea supported the research.

Nano rods on lotus(Courtesy of M. -W. Moon, KIST)

Nano thresholds of sandfishI. Rechenberg et al. Tech. Univ. Berlin Fachgebiet: Bionik und Evolutionstechnik, 2009

Nano ribs of sharksD.-Y. Zhao, et al. J. Mat. Proc. Tech. 212, 2012.

Typical surface nanostructures for various functions in nature. Wrinkle folding is expected to create

artificially such for various applications.

By Richard Lewis


Novel device removes heavy metals from water

The technique is scalable and has viable commercial applications, especially in the environmental remediation and metal re-covery fields. Results appear in the Chemical Engineering Journal.

An unfortunate consequence of many in-dustrial and manufacturing practices, from textile factories to metalworking operations, is the release of heavy metals in waterways. Those metals can remain for decades, even centuries, in low but still dangerous concen-trations.

Ridding water of trace metals “is really hard to do,” said Joseph Calo, professor emeritus of engineering who maintains an active laboratory at Brown. He noted the cost, in-efficiency, and time needed for such efforts. “It’s like trying to put the genie back in the bottle.”

That may be changing. Calo and other en-gineers at Brown describe a novel method that collates trace heavy metals in water by increasing their concentration so that a proven metal-removal technique can take over. In a series of experiments, the engi-neers report the method, called the cyclic electrowinning/precipitation (CEP) system, removes up to 99 percent of copper, cad-mium, and nickel, returning the contami-nated water to federally accepted standards of cleanliness. The automated CEP system is scalable as well, Calo said, so it has viable commercial potential, especially in the envi-ronmental remediation and metal recovery fields. The system’s mechanics and results are described in a paper published in the Chemical Engineering Journal.

A proven technique for removing heavy metals from water is through the reduction of heavy metal ions from an electrolyte. While the technique has various names, such as electrowinning, electrolytic remov-al/recovery or electroextraction, it all works the same way, by using an electrical current to transform positively charged metal ions (cations) into a stable, solid state where they can be easily separated from the water and removed. The main drawback to this tech-nique is that there must be a high-enough concentration of metal cations in the water for it to be effective; if the cation concentra-tion is too low — roughly less than 100 parts per million — the current efficiency be-comes too low and the current acts on more than the heavy metal ions.

Another way to remove metals is through simple chemistry. The technique involves using hydroxides and sulfides to precipitate the metal ions from the water, so they form solids. The solids, however, constitute a tox-ic sludge, and there is no good way to deal with it. Landfills generally won’t take it, and letting it sit in settling ponds is toxic and en-vironmentally unsound. “Nobody wants it, because it’s a huge liability,” Calo said.

The dilemma, then, is how to remove the metals efficiently without creating an un-healthy byproduct. Calo and his co-authors, postdoctoral researcher Pengpeng Grim-shaw and George Hradil, who earned his doctorate at Brown and is now an adjunct professor, combined the two techniques to

Engineers at Brown University have developed a system that cleanly and efficiently removes trace

heavy metals from water. In experiments, the researchers showed the system reduced cadmium,

copper, and nickel concentrations, returning contaminated water to near or below federally

acceptable standards.

f r o M T H E L a B S Joseph M. Calo

13 SUMMER 2012


By Richard Lewis

form a closed-loop system. “We said, ‘Let’s use the attractive features of both methods by combining them in a cyclic process,’” Calo said.

It took a few years to build and develop the system. In the paper, the authors describe how it works. The CEP system involves two main units, one to concentrate the cations and another to turn them into stable, solid-state metals and remove them. In the first stage, the metal-laden water is fed into a tank in which an acid (sulfuric acid) or base (sodium hydroxide) is added to change the water’s pH, effectively separating the water molecules from the metal precipitate, which settles at the bottom. The “clear” water is si-phoned off, and more contaminated water is brought in. The pH swing is applied again, first redissolving the precipitate and then reprecipitating all the metal, increasing the metal concentration each time. This process is repeated until the concentration of the metal cations in the solution has reached a point at which electrowinning can be effi-ciently employed.

When that point is reached, the solution is sent to a second device, called a spouted particulate electrode (SPE). This is where the electrowinning takes place, and the metal cations are chemically changed to stable metal solids so they can be easily removed. The engineers used an SPE developed by Hradil, a senior research engineer at Tech-nic Inc., located in Cranston, R.I. The cleaner water is returned to the precipitation tank, where metal ions can be precipitated once again. Further cleaned, the supernatant water is sent to another reservoir, where additional processes may be employed to

further lower the metal ion concentration levels. These processes can be repeated in an automated, cyclic fashion as many times as necessary to achieve the desired perfor-mance, such as to federal drinking water standards.

In experiments, the engineers tested the CEP system with cadmium, copper, and nickel, individually and with water contain-ing all three metals. The results showed cad-mium, copper, and nickel were lowered to 1.50, 0.23 and 0.37 parts per million (ppm), respectively — near or below maximum contaminant levels established by the En-vironmental Protection Agency. The sludge is continuously formed and redissolved within the system so that none is left as an environmental contaminant.

“This approach produces very large volume reductions from the original contaminated water by electrochemical reduction of the ions to zero-valent metal on the surfaces of the cathodic particles,” the authors write. “For an initial 10 ppm ion concentration of the metals considered, the volume reduc-tion is on the order of 106.”

Calo said the approach can be used for other heavy metals, such as lead, mercury, and tin. The researchers are currently testing the system with samples contaminated with heavy metals and other substances, such as sediment, to confirm its operation.

The research was funded by the National In-stitute of Environmental Health Sciences, a branch of the National Institutes of Health, through the Brown University Superfund Research Program.


Senator Reed, federal and state officials tourBrown’s Superfund LabSenator Jack Reed, accompanied by the New England regional director of the U.S. Environmental Protection

Agency and the directors of the state’s environmental and health departments, visited Brown University’s

Superfund Research Program Monday, April 9, 2012. The Brown program is one of 14 research groups funded by

the National Institutes of Health.

Brown’s Superfund research group has been in operation since 2005. The program has brought in some $43 million in fund-ing to Rhode Island since then, creating or supporting 45 jobs in the Ocean State. The group is working on the Centredale Manor Superfund site in Providence, the Gorham Manufacturing site in Providence, and the well-publicized soil contamination affect-ing residential properties in the Bay Street neighborhood in Tiverton. In these cases, scientists and students have tracked the flow of hazardous gases from contaminated sites, identified and tested toxic chemicals, worked with community and neighbor-hood associations and state and federal agencies to clean up contaminated areas, and offered insights into how chemicals can alter human health and reproduction.

“Rhode Island is a small, densely populat-ed state with a proud industrial heritage, yet burdened by a toxic legacy,” said Kim Boekelheide, professor of medical science and a member of Brown’s Superfund re-search group. “Brown’s Superfund Research Program is a center of technical excellence, where we focus on new scientific approach-es to clean up our post-industrial legacy of contaminated sites here in the Ocean State and throughout the nation.”

Reed toured the Brown group’s facility in the Laboratories for Molecular Medicine, 70 Ship St. in Providence, at 12:30 p.m. He was accompanied by Gwen Collman, director of extramural research and training, National Institute of Environmental Health Sciences (NIEHS), the program’s primary funder; Curt Spalding, New England administrator for

In addition to working on contaminated sites in Rhode Island, the Brown Superfund Research Program connects to Superfund sites nationwide, primarily through re-search. Specifically, the group has:

• Devised a computational model with the Rhode Island Department of Environmental Management to track the flow of contami-nant vapors from groundwater and soil into homes and businesses. The model has been tested at the Gorham site in Rhode Island and is currently being tested at a hazardous waste site in Somerville, Mass.

• Investigated the potential environmental hazards from consumer products using nanomaterials (dimensions one-billionth of a meter, or 1/50,000th the width of a human hair). Current projects are looking at the re-lease of nanosilver into sewer systems, how nanomaterials break down in landfills and how they infiltrate human lungs.

• Studied the effects of chemicals on human sperm and human female reproduction, especially pregnant women and chemically induced premature births.

“Putting people to work to reduce the negative impacts

of abandoned hazardous waste sites is a smart

investment to protect public health, the environment, and

our economy,” said Reed. “I am pleased that Brown’s

federally funded Superfund Research Program is working

through targeted research and community outreach

to address health concerns and design novel techniques

to reduce toxic chemicals at Superfund sites in

Rhode Island.”

the EPA; Janet Coit, Rhode Island Depart-ment of Environmental Management direc-tor; and Michael Fine, Rhode Island Depart-ment of Health director. Brown Provost Mark Schlissel also toured the facility.

The nano-material photo shows a human lung macrophage engulfing a graphene nanomaterial


15 SUMMER 2012


The Brown Superfund Program has created innovative ways to connect with local com-munities and develop the next generation of environmental leaders. The centerpiece of this effort is the Community Environmen-tal College, an eight-week summer lead-ership program for inner-city youth. Last year, nearly 50 urban high-school students, primarily in Providence and Pawtucket, en-gaged in various activities to raise commu-nity awareness of the environment, ranging from enlisting Latino restaurants to supply used vegetable oil for biodiesel fuel, recy-cling mattresses, and encouraging conve-nience stores to stock healthier food. Brown students work with youth and community

groups on myriad projects, including a year-round after-school program called ECO Youth, weatherizing homes and the “Hos-pitals for a Healthy Environment in Rhode Island” programs, which promotes cost-ef-fective, healthy, and sustainable health-care institutions.

“Through our Community Engagement Core, we help local groups clean up contam-inated land and work with legislators and regulators to strengthen state policies on brownfields, school siting, and various en-vironmental justice issues,” said Phil Brown, professor of sociology at Brown and a re-searcher with the Superfund Research Pro-gram. “I am excited about our engagement with so many high school students in the Community Environmental College, as they learn so much and apply themselves to the Healthy Corner Store Initiative, weatheriza-tion, green transportation, and other critical concerns.”

By Richard Lewis

The Brown Superfund Research Program is up for renewed funding in 2014. The renew-al comes amid a competitive landscape; a decade ago, the federal Superfund Research Program supported 21 such programs na-tionwide.

“Continued funding will allow us to improve the prediction of the health risks associated with complex chemical exposures and de-vise new remediation strategies for contam-inated sites,” Boekelheide said.

Postdoctoral Researcher Pengpeng Grimshaw takes samples from a Rhode Island riverbank to assess possible contaminant levels and study novel cleanup processes that have been devel-oped in a Superfund lab at Brown.

Clockwise from left: Ed Dere, Postdoctoral Researcher, Brown University; Curt Spalding, Administrator forEPA’s New England Region (Region1); Steve Hourihan, Governor Lincoln Chafee’s office; Senator Jack Reed. Photography: Mike Cohea/Brown University


fa c U LT y a w a r D S

Andrew Peterson, assistant professor of engineering, has won a Young Investigator Award from the U.S. Navy. Peterson, one of only 26 young faculty nationwide to be selected, was recognized for scientific pursuits that show exceptional promise for the Navy and Marine Corps. The award is intended to promote the researcher’s professional development; Peter-son will receive three years’ funding for research that could advance naval technology, the Navy announced Tuesday, March 27.

Peterson joined the Brown faculty in January. His primary research is devoted to figuring out how to produce carbon-based fuels from renewable sources. A key to such a breakthrough lies in overcoming the steep energy threshold needed to split carbon dioxide molecules into hydrocarbons. Peterson’s approach is to rely on quantum mechanics calculations to design catalysts to make those reactions more efficient and less costly.

Andrew Peterson named Young Investigator

Professor Kyung-Suk Kim PhD ’80 to Receive 2012 Engineering Science Medal

Brown University School of Engineering Professor Kyung-Suk Kim PhD ’80 will receive the 2012 Engineer-ing Science Medal from the Society of Engineering Science (SES). The prize is awarded in recognition of a singularly important con-tribution to engineering

science. Professor Kim will receive his award during the 49th Annual Technical Meeting of the Society of Engineering Science to be held at Georgia Institute of Technology from October 9-12, 2012. The Society of Engineering Science has only awarded the Engineering Science Medal eight previous times since its inception in 1987.

“This is a tremendous and well-deserved honor for Professor Kim,” said Dean Larry Larson. “As both a Brown Engineering alumnus and professor we are extremely proud of his accomplishments and look forward to his continued contributions to the field.”

Professor Kim receives the prize for his singularly important contri-butions to experimental micro and nano-mechanics. These include his inventions of transverse displacement interferometer for high strain rate combined normal and shearing load, stress intensity trac-er for time dependent fracture testing, Moiré interferometry for finite

displacement measurement at the micro and nano-length scales, field projection methods to extract cohesive laws, residual stress measurements via chemical etching, high resolution TEM analysis to extract near atomic resolution constitutive laws and extension of the AFM range to measure the size scaling in contact and adhesion.

Professor Kim received his B.S. and M.S. degrees from Seoul National University of Korea in 1974 and 1976, respectively, and his Ph.D. from Brown University in 1980. He worked on the faculty of the University of Illinois at Urbana-Champaign from 1980-1989 before returning to Brown as Professor of Engineering in 1989. He is currently the di-rector of Nano and Micromechanics Laboratory in the Mechanics of Solids and Structures Group in the School of Engineering at Brown University.

Founded in 1963, the Society of Engineering Science (SES) was es-tablished to promote the free exchange of information on all as-pects of engineering science and to provide a forum for discussion, education, and recognition of the talents of the engineering science community. Since its founding in 1963, the SES has established its reputation as the most vibrant and relevant technical society to pro-mote the field of engineering science, where science and engineer-ing meet. The annual technical meetings organized by SES bring leading engineers, scientists and mathematicians from around the world together to tackle some of the most challenging problems at the interface between engineering, sciences and mathematics.

17 SUMMER 2012

Huajian Gao, Walter H. Annenberg Profes-sor of Engineering at Brown University, has been elected to the National Academy of Engineering (NAE). Gao, honored for contri-butions to micromechanics of thin films and hierarchically structured materials, is one of 66 new members and 10 foreign associates elected, and is one of just 2,254 U.S. mem-bers and 206 foreign associates in the NAE.

Election to the National Academy of Engi-neering is among the highest professional distinctions accorded to an engineer. Acad-emy membership honors those who have made outstanding contributions to "engi-neering research, practice, or education, including, where appropriate, significant contributions to the engineering literature," and to the "pioneering of new and devel-oping fields of technology, making major advancements in traditional fields of engi-neering, or developing/implementing in-novative approaches to engineering educa-tion."

Professor Gao becomes the ninth member of the Brown School of Engineering faculty to be elected to the National Academy of Engineering. He joins William Prager (elect-

fa c U LT y a w a r D S

Professor Huajian Gao Elected to the National Academy of Engineering

engineering science. He has more than 25 years of research experience and more than 300 publications to his credit.

Professor Gao’s research group is gener-ally interested in understanding the basic principles that control mechanical proper-ties and behaviors of both engineering and biological systems. His current research includes studies of how metallic and semi-conductor materials behave in thin film and nanocrystalline forms, and how bio-logical materials such as bones, geckos, and cells achieve their mechanical robustness through structural hierarchy.

ed 1965), Daniel C. Drucker (elected 1967), James R. Rice (elected 1980), Joseph Kestin (elected 1982), Rush C. Hawkins University Professor Rod Clifton (elected 1989), Profes-sor Emeritus L.B. Freund (elected 1994), Pro-fessor Emeritus Alan Needleman (elected 2000), and Vice President for Research and Otis Randall University Professor Clyde Bri-ant (elected 2010).

"This is a spectacular professional achieve-ment for Professor Gao and we are extreme-ly happy for him," said Dean Larry Larson. "To have five members of the National Academy within a faculty of 40 also underscores the strength and level of accomplishment of our faculty here at Brown.”

Professor Gao received his B.S. degree from Xian Jiaotong University of China in 1982, and his M.S. and Ph.D. degrees in engineer-ing science from Harvard University in 1984 and 1988, respectively. He served on the faculty of Stanford University between 1988 and 2002, where he was promoted to asso-ciate professor with tenure in 1994 and to full professor in 2000. He was appointed as Director and Professor at the Max Planck In-stitute for Metals Research in Stuttgart, Ger-many between 2001 and 2006. He joined Brown University in 2006. Professor Gao has a background in applied mechanics and

NATIONAL ACADEMYOF ENGINEERING


fa c U LT y r E c o g N I T I o N

Legendary engineering professor Bar-rett Hazeltine has been recognized by The Princeton Review as one America’s top un-dergraduate professors in its latest guide-book, The Best 300 Professors. The book profiles professors in 60 fields based on surveys by The Princeton Review and rat-ings on RateMyProfessors.com, the highest trafficked college professor ratings site in the country.

Data from RateMyProfessors.com identi-fied more than 42,000 professors, and was culled down to a base list of 1,000 profes-sors. After obtaining further input from uni-versity administrators and students, along with The Princeton Review’s surveys of the professors under consideration, the edi-tors of The Princeton Review made the final choices of the professors.

Professor Hazeltine has taught engineer-ing, management, and technology courses at Brown for more than 50 years, and cur-rently teaches Management of Industrial and Non-Profit Organizations, Managerial Decision Making, and Appropriate Tech-nology. He received awards for teaching from thirteen senior classes at Brown, 1972 to 1984, and 1990. In 1985, this award was named after him.

Brown’s Barrett Hazeltine Named one of America’s “Best 300 Professors” by The Princeton Review

“Professor Hazeltine has touched the lives of so many Brown students over the years,” said John Stamler ’98, Brown University alum and investment professional at Wayzata Investment Partners “I always looked forward to attending Professor Hazeltine’s classes knowing they would be thought provoking, interest-ing and challenging. His passion for his subject and commitment to all of his students made him extra special. He is a true asset to Brown University.”

19 SUMMER 2012

M E E T T H E N E w P r E S I D E N T

On Tuesday, March 20, Dean Larry Larson had the pleasure of leading President-Elect Christina Paxson on a tour of Barus and Hol-ley, Prince Lab, and the Giancarlo Labs. This was the President-Elect’s first extended visit to campus since her selection as the Univer-sity’s 19th President on March 2. During the visit, Paxson also met with senior adminis-trators and faculty members and toured the libraries.

During her tour of the School of Engineer-ing, President-Elect Paxson had the oppor-tunity to meet many professors, graduate and undergraduate students, and staff, and see demonstrations of some of the research that is being conducted at the School.

Outstanding faculty members Arto Nur-mikko, Gabriel Taubin, Ben Kimia, Rashid Zia, Chris Bull, Kenny Breuer, and Nitin Padture explained some of their ongoing research projects to the President-Elect.

She also had the opportunity to sit in on Professor Allan Bower’s fresh-man EN0040 class, where she was able to see student presentations.

“Having the opportunity to present our project to President-Elect Pax-son was wonderful, not only because she had a very friendly and ami-able demeanor, but also because she showed evident appreciation for our ideas,” said Emily Toomey ’15.

“Although the project at first seems like it has a simple objective, it required a great deal of collaboration, creativity, and application of engineering principles to create a successful result. By asking questions about our thought processes and how the MATLAB functions worked, President-Elect Paxson displayed a genuine in-terest in our efforts that made the project even more worthwhile,” added Toomey.

“What I enjoyed most about President-Elect Paxson's visit was the genuine interest that she showed in understanding our project,” said Maggie Coats-Thomas ’15. “The questions that she asked made it clear that she understood what was going on and appre-ciated our efforts, which I thought was very rewarding. She was very friendly and I am so pleased I got the opportunity to interact with her so soon after she was elected.”

The tour also provided the new President-Elect with the oppor-tunity to see some of the space and facility constraints and chal-lenges that currently exist in Barus & Holley. In an interview with the Brown Daily Herald, Paxson said of engineering, “it is clear that they’ve had a lot of growth, but they’re very tight on space.”

Overall, the tour was a great success in showcasing both the excit-ing work that is happening in the School of Engineering, and the need for expansion and growth.

President-Elect Paxson Visits School of Engineering

Left to Right: Wendy Ginsberg ’15, Emily Toomey ’15, President-Elect Paxson, Dean Larry Larson, Selena Buzinky ’15, Professor Rod Clifton, and Omar Nema ’15.

Professor Gabriel Taubin shows President-Elect Paxson the video wall constructed by his group as a prototype platform to develop new computer vision technologies to enable groups of users to interact with large format displays in collaborative environments, as well as remote collaboration of multiple groups across large distances.


S T U D E N T S I N T H E N E w S

My intensive two-week introduction to in-ternational spaceflight began with cloud-less skies and 95% humidity on the campus of NASA, Houston. There, with Dr. Michael Kezirian ‘89 as guide and host, I was given the full tour of Johnson Space Center fa-cilities including the SAIL (Shuttle Avionics Integration Laboratory), the NBL (Neutral Buoyancy Laboratory), the shuttle docking simulator, Mission Control Center, and nu-merous other shuttle and space centered projects. We met a few somber souls who were soon to lose their shuttle-related jobs upon shuttle “wheel stop”, uncertain about the future. At the same time, in a brief tour just down the road, we met the hopeful fac-es of the employees at Ad Astra Rocket Com-pany, looking forward to the future usage of ion propulsion in deep space travel. All of my exposures to U.S. space travel in Hous-ton would turn out to be the perfect preface to the ensuing experience on the Moscow Space Summer Internship Program (MSSIP).

I soon met up with the eight other American students accepted into the program, hailing

from USC, UTEP, Rice University, and Uni-versity of Houston. The MSSIP, founded by the Baker Institute for Public Policy at Rice University, was to send us nine American students to participate in Space Develop-ment: Theory and Practice (STDP), hosted by Bauman Moscow State Technical University (BMSTU). This act of public policy was made in part to establish precedence for interna-tional space collaboration, and would be the first time SDTP had admitted American students since its beginnings in 1996. Thus, we departed Houston on the 6,000 mile journey to Moscow to join the other 50 stu-dent participants from over ten different countries including Switzerland, France, Germany, England, Australia, South Korea, Greece, and of course, Russia.

We were met at the Domodedovo Airport by Russian students of BMSTU, with whom we would be spending the next two weeks. After stopping by our dorms and meeting the other participants, we plunged right into the amazing cultural portion of the trip which started off with a quick tour through

Red Square and Alexander’s Garden. Throughout the rest of our time in Moscow, we visited markets, saw the “Black Swan” performed by the Russian Ballet, indulged in Russian foods, and toured historic sites such as the Kremlin, The Holy Trinity-St. Sergius Lavra, and the Tretyakov Gallery. Our cul-tural experience was topped off with a night out on popular Arbat Street and a boat trip up and down the Moscow River. These cul-tural activities were well integrated into the entirety of the trip, but were heavily supple-mented with the real focus of the program: the Russian Space Agency, or Roscosmos.

Who better to introduce us to Roscosmos than world-renowned cosmonaut, Sergei Krikalev? Having spent more time than any other human in space (800+ days), it was incredible to have the chance to speak with him and shake his hand. The trip continued with tours of multiple space museums and functioning facilities. At Zvezda, a research, development and production enterprise for Roscosmos and the Russian military, we learned about the design and history of Russian space suits and ejection seats. At Mission Control Center in Korolev we were given a unique opportunity to hold a long distance real-time Q&A video conference with the Russian cosmonauts aboard the International Space Station. Every student was extremely curious about life in space and we were truly lucky to hear about it straight from the source. Other learning experiences included visits to the Memorial Museum of Cosmonauts, Monino Air Force museum, and BMSTU’s own University Edu-cational and Experimental Center. Some of these museums offered a unique touch-anything policy, giving us a chance, for ex-ample, to actually climb into the Russian lu-nar lander (built in the ’60s but never flown) at the Educational and Experimental Center. At the Gagarin Cosmonaut Training Center in Star City, we were given a tour of cosmo-naut training facilities such as the centrifuge

Brown Engineering in Moscow!by Alexander Grosvenor ’12

Russian Cosmonaut Sergei Krikalev (center) with Nick Helmer, USC, (left) and Alex.

21 SUMMER 2012

trainer, their equivalence of the Neutral Buoyancy Lab, the Soyuz, and other systems mock-ups. Here, the intense pride that the Russians have for their human spaceflight capabilities was very evident.

In addition to our history lessons and vis-iting of space program exhibits, we were given lectures, usually in Russian and trans-lated to English, by Bauman professors on topics of space flight. These included les-sons on robotics, ballistic trajectories, rock-etry, and thermal control. We even had the opportunity to build and launch our own model rockets. Three American students, including myself, took first, second and third in the flight duration competition.

The culmination of this program of inter-national cooperation was the team project, the goal of which was to design a Mercurial rover that could demonstrate the same ca-pabilities as the currently operable Mars rov-ers. The entire project was divided into five specialized groups including ballistics, ther-mal control, robotics, electrical control sys-tems, and general design. One of the main problems was designing a rover that could withstand the extreme radiation and vola-

tile temperatures on Mercury. As a member of the thermal design group, I was person-ally involved in brainstorming solutions for this untested dilemma. We worked to tackle this problem by using a combination of con-centrating parabolic mirrors, solar radiation collectors, excess heat radiators, multi-layer insulation, and of course, teamwork and problem solving skills. The final rover design was presented to the President of BMSTU and directors of SDTP as well as some mem-bers of the local media.

At the end of this program I realized that the interpersonal experiences and relation-ships formed with students from all over the globe were some of the most valu-able aspects of the trip - and arguably the purpose of this trip. By working and living with international engineering students for almost two weeks I gained life-long friend-ships and was able to experience and pro-mote the international cooperation that will be necessary as humanity begins to explore deep space. I am very thankful to the stu-dents of Bauman University and organizers

of Space: Development, Theory and Practice 2011 as well as all those at the Baker Institute of Rice University who made this trip pos-sible. I look forward to seeing the growth of the program within the Brown Univer-sity School of Engineering, and I’m happy to report that this summer three more Brown students - Ian Brownstein ’13, Brady Casper ’13, and Nathaniel Gilbert ’13 - will have the opportunity to participate in the program.

In the pilot’s seat, testing the shuttle simulator for “take-off”.

Touring the Gagarin Space Museum.


CAD model, created in Solidworks, of final rover design includes solar collector and deflector, a camera system and internal scientific instruments, 6-axis robotic arm with various tools attached, and a chassis system.



Hear me now?

Everyone does signal processing every day, even if we don’t call it that. With friends at a sports bar, we peer up at the TV to see the score, we turn our head toward the crash-ing sound when a waitress drops a glass, and perhaps most remarkably, we can track the fast-paced banter of all the people in our booth, even if we’ve never met some of the friends-of-friends who have insinuated themselves into the scene.

Very few of us, however, could ever get a computer to do anything like that. That’s why doing it well has earned Brian Reggi-annini a Ph.D. at Brown and a career in the industry.

In his dissertation, Reggiannini managed to raise the bar for how well a computer con-nected to a roomful of microphones can keep track of who among a small group of speakers is talking. Further refined and com-bined with speech recognition, such a sys-tem could lead to instantaneous transcrip-tions of meetings, courtroom proceedings, or debates among, say, several rude political candidates who are prone to interrupt. It could help the deaf follow conversations in real-time.

If only it weren’t so hard to do.

But Reggiannini, who came to Brown as an undergraduate in 2003 and began build-ing microphone arrays in the lab of Harvey Silverman, professor of engineering, in his junior year, was determined to advance the state of the art.

The specific challenge he set for himself was real-time tracking of who’s talking among at least a few people who are free to rove

around a room. Hardware was not the is-sue. The test room on campus has 448 mi-crophones all around the walls and he only used 96. That was enough to gather the kind of information that allows systems – think of your two ears – to locate the source of a sound.

The real rub was in devising the algorithms

and, more abstractly, in realizing where his reasoning about the problem had to aban-don the conventional wisdom.

Previous engineers who had tried some-thing like this were on the right track. After all, there is only so much data available in situations like this. Some tried analyzing accents, pronunciation, word use, and ca-dence, but those are complex to track and require a lot of data. The simpler features are pitch, volume, and spectral statistics (a breakdown of a voice’s component waves and frequencies) of each speaker’s voice. Systems can also ascertain where a voice came from within the room.

Snippets, not speaker

But many attempts to build speaker identifi-cation systems (like the voice recognition in your personal computer) have relied on the idea that a computer could be extensively trained in “clean,” quiet conditions to learn a speaker’s voice in advance.

One of Reggiannini’s key insights was that just like a politician couldn’t possibly be primed to recognize every voter at a rally, it’s unrealistic to train a speaker-recognition system with the voice of everyone who could conceivably walk into a room.

Instead, Reggiannini sought to build a sys-tem that could learn to distinguish the voices of anyone within a session. It analyzes each new segment of speech and also notes the distinct physical position of individuals within the room. The system compares each new segment, or snippet, of what it hears to previous snippets. It then determines a statistical likelihood that the new snippet would have come from a speaker it has al-ready identified as unique.

“Instead of modeling talkers, I’m going to in-stead model pairs of speech segments,” Reg-giannini recalled.

A key characteristic of Reggiannini’s system is that it can work with very short snippets of speech. It doesn’t need full sentences to work at least somewhat well. That’s impor-tant because it’s realistic. People don’t speak in florid monologues. They speak in frac-tured conversations. No way! Yes, really.

People also are known to move around. For that reason position as inferred by the array

If computers could become ‘smart’ enough to recognize who is talking, that could allow them to produce real-

time transcripts of meetings, courtroom proceedings, debates, and other important events. In the dissertation

that will allow him to receive his Ph.D. at Commencement this year, Brian Reggiannini ‘07 ScM ‘09 PhD ‘12 found

a way to advance the state of the art for voice- and speaker-recognition.

“We’re trying to teach a computer how to do something

that we as humans do so naturally that we don’t even understand

how we do it.”

Brian Regiannini

23 SUMMER 2012

Touring the Gagarin Space Museum.


of microphones can be only an intermittent asset. At any single moment in time, espe-cially at the beginning of a session, position helpfully distinguishes each talker from ev-ery other (no two people can be in the same place at the same time), but when people stop talking and start walking, the system necessarily loses track of them until they speak again.

Reggiannini tested his system every step of the way. His experiments included just pitch analysis, just spectral analysis, a combina-tion of the two, position alone, and a com-bination of the full speech analysis and posi-tion tracking. He subjected the system to a multitude of voices, sometimes male-only, sometimes female-only, and sometimes mixed. In every case, at least until the speech snippets became quite long, his system was better able to discriminate among talkers than two other standard approaches.

That said, the system sometimes is uncer-tain and in cases like that it defers assign-ing speech to a talker until it is more certain. Once it is, it goes back and labels the snip-pets accordingly.

It’s no surprise that the system would err, or hedge, here and there. Reggiannini’s test room was noisy. While some systems are fed very clean audio, the only major conces-sions that Reggiannini allowed himself were that speakers wouldn’t run or jump across the room and that only one would speak from the script at a time. The ability to filter individual voices out from within overlap-ping speech is perhaps the biggest remain-ing barrier between the system remaining a research project and becoming a commer-cial success.

A career in the field

While the ultimate fate of Reggiannini’s in-novations is not yet clear, what is certain is

that he has been able to embark on a career in the field he loves. Since leaving Brown last summer he’s been working as a digital sig-nal processing engineer at Analog Devices in Norwood, Mass., which happens to be his hometown.

Reggiannini has yet to work on an audio project, but that’s fine with him. His interest is the signal processing, not sound per se. Instead he’s applied his expertise to chal-lenges of heart monitoring and wireless communications.

“I’ve been jumping around applications but all the fundamental signal processing theory applies no matter what the signal is,” he said. “My background lets me work on a wide range of problems.”

After seven years and three degrees at Brown, Reggiannini was prepared to pursue his passion.

Real-time tracking of who’s talking. With the right algorithms and signal processing software, an array of button-size microphones placed around the perimeter of a room can identify, follow, and record each of several people as they move about, interrupt each other, and converse. Photography: Frank Mullin/Brown University

by David Orenstein



Since its inception in 2006, Brown Engineers Without Borders (EWB) has been a dedicated group of passionate students intent on build-ing a better world by applying their problem-solving skills and en-thusiasm beyond the classroom walls. Our members’ work has im-pacted people around the world, from Peru, Kenya, and India to the Dominican Republic. Past international projects include setting up a health clinic, aiding Amaranth farming, and setting up a water-har-vesting program and a water distribution-filtration system.

This year, Brown EWB reached out to the local community of Provi-dence in partnership with the Hub, a community center in down-town Providence, through an after-school program for students from Juanita Sanchez High School. This program has been a reward-ing opportunity both for the Brown EWB students-turned-instruc-tors and for our students who gain high-school course credit by learning engineering skills through interactive, fun projects. In the spirit of our mission statement, this program aims at empowering communities through sustainable engineering projects. By sharing our knowledge of sustainable development and by enabling these students to make their own LED cubes and mini wind-turbines, it is our hope that they will come away with a sense that they can change society through passion and dedication.

During spring break in 2011, five of our members went to La Tina-jita, Dominican Republic to bring a water distribution and filtration project to fruition, in collaboration with A Mother’s Wish Founda-tion, a local non-governmental organization (NGO). Our contact with La Tinajita was a humbling and enriching experience. We ex-perienced the vivid contrast between our comfortable campus and the community, the old TVs and refrigerators in their homes are just

Rita (co-founder of A Mother’s Wish Foundation), Matt Jasmin ‘09, Joy Nkosi ‘11, a community member, Sharon Makava ‘11 and Karine Ip Kiun Chong ‘12: discussing the pipe network from the blue filtration tank to the storage tank and water point.

Brown’s Engineers Without Borders Brings Water to a Village in the Dominican Republic

by Karine Ip Kiun Chong ‘12

a backdrop, serving as decoration and storage due to the scarcity of electricity. Water is a scarce commodity for them as the women walk daily to the nearby stream to wash their clothes and fill their bath tub. Brown EWB felt that this aspect was something we could improve on, hence responded to the community’s call for assistance for setting up a water distribution-filtration system.

A typical day in La Tinajita: Work started at 8:00 a.m. for our members to preempt the midday heat, before they would catch the heat of the day later on. Initial investigation and GPS topographical mapping had shown us suitable spring sources which could be tapped. Our engineering team chose a gravity-fed distribution system to take advantage of La Tinajita’s hilly terrain. We journeyed through the grassland looking for the water source and, once found, linked PVC pipes to direct water downhill to the two communal tanks, one of which led to a biosand filter. Because this region was prone to floods during the rainy season, it was essential to build a sustainable strong concrete base for the biosand filter, a task we completed with much help from the men of the village who are used to building their own houses out of bricks and cement, wood and corrugated sheets. At the end of a week’s work, we came away with the memory of the grateful smiles of the community members, the peace of mind that they had working taps near their home, and the assurance that they are empowered to maintain the water supply network and filter.

This year, we hope to establish a long term relationship with a barrio in the city of Tireo in Dominican Republic. This summer, we will be sending two representatives to forge relationships with community leaders to truly comprehend the most pressing health needs of each community. For more information, please go to: students.brown.edu/ewbTo discuss ways you can assist EWB, or make a donation to EWB, please contact [email protected] or 401.863-9877

Sharon Makava ‘11, Joy Nkosi ‘11, Karine Ip Kiun Chong ‘12 and Matt Jasmin ‘09 discussing the building of the tank’s concrete base, while the community leader’s daughter (far right) watches on intently.

25 SUMMER 2012

How did your time at Brown Engineering shape who you are?

When I consider this question, my mind floods with examples of how Brown and Brown Engi-neering helped form me – personally and pro-fessionally. My Brown experience gifted me by shaping several personal traits like my work ethic, problem solving skills, global perspec-tive and character.

The office hours I spent with professors taught me to seek out experts. The late nights spent work-ing on group projects with peers taught me the value of team-work. I solidified my work ethic and time management skills when I successfully juggled my academic, extracur-ricular and social life at Brown.

Brown gifted me with many things. Now it is my turn to give back to Brown. I do so finan-cially and directly with my time invested as the chair of the School of Engineering Advisory Council. I am gratified to see how engineer-ing at Brown is forming as we complete our second year as the School of Engineering. The University, our Dean, our faculty and staff, and our current students benefit directly from the time and resources that each of us gives back.

How will you give back to Brown? Can you hire a Brown engineering undergrad as a summer intern? Can you interview prospective Brown students in your region? Can you partner with the college and sponsor research? Can you provide financial support with annual giving? No matter how you choose to add value to Brown, Brown will benefit from your engage-ment, as will you.

Deirdre Hanford ’83

Sangeeta N. Bhatia ’90Professor, Investigator, Director: Laboratory for Multiscale Regenerative TechnologiesMITCambridge, MA

John Bravman PresidentBucknell UniversityLewisburg, PA

Seth coe-Sullivan ’99 Chief Technology Officer QD VisionLexington, MA

Dr. rick fleeter ’76 Ph.D.’81Author/Adjunct Professor Brown University Providence, RILa Sapienza /University of RomeRome, Italy

Thomas f. gilbane, Jr. ’69 P’97 P’98 P’00Chairman & CEOGilbane Building CompanyProvidence, RI

D. oscar groomes ’82 P’15Metallurgical Engineer, Physicist and Materials Scientist Groomes Business SolutionsCharlotte, NC

Deirdre Hanford ’83 - chairSenior Vice President, Global Technical ServicesSynopsys, Inc.Mountain View, CA

David Hibbitt Ph.D.’72 PMaT’96Co-Founder ABAQUS, Inc.Providence, RI

alejandro Knoepffler ’82PrincipalCipher Investment Management Co.Coral Gables, FL

Peter Lauro ’78 P’11PartnerEdwards Wildman Palmer, LLPBoston, MA

Joann LightyChair, Professor of Chemical EngineeringUniversity of UtahSalt Lake City, Utah

andrew Marcuvitz ’71 P’06Founder, ChairmanAlpond Capital, LLCLincoln, MA

James r. Moody ’58 Sc.M.’65 P’97PresidentCo-Planar, Inc.Denville, NJ

Venkatesh “Venky” NarayanamurtiDirectorScience Technology /Public Policy ProgramHarvard Kennedy School Cambridge, MA

James B. robertoAssociate Laboratory DirectorOak Ridge National LaboratoryOak Ridge, TN

Paul Sorensen ’71 Sc.M.’75 Ph.D.’77 P’06 P’06Co-FounderABAQUS, Inc.Providence, RI

Donald L. Stanford ’72 Sc.M.’77Chief Innovation OfficerGTECHAdjunct ProfessorBrown UniversityProvidence, RI

James E. warne, III ’78President WTI, Inc. Phoenix, AZ

School of Engineering Advisory Council Members Hanford on Alumni Involvement

aDVISory coUNcIL/aLUMNI INVoLVEMENT

Engineering Advisory Council Mission

Provide support and advice in the development, execution, and attainment of the School of Engineering’s strategic goals.Ensure the School of Engineering is providing the highest quality educational experience for its students, and is embarking on the highest impact,

highest quality, research program.Coordinate with the Engineering Development Committee to ensure that our strategic and financial initiatives are achieved.Work with campus leadership to ensure their continued support of the School of Engineering, and recognition of the key role Engineering plays in

the vitality of the entire Brown community.

School of Engineering Development Committeecharlie giancarlo ’79 P’08 P’11Managing DirectorSilver Lake PartnersMenlo Park, CA

Theresia gouw ranzetta ’90PartnerAccel PartnersPalo Alto, CA

Joan wernig Sorensen ’72 P’06 P’06Providence, RI

Paul Sorensen ’71 Sc.M.’75 Ph.D.’77 P’06 P’06Co-FounderABAQUS, Inc.Providence, RI

c o M M E N c E M E N T 2 0 1 2

School of EngineeringBox D182 Hope StreetProvidence, RI 02912

To view additional pictures from Commencement, please visit: http://tiny.cc/qkytgw

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