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 9:00 a.m., 10:00 a.m., and 11:00 a.m. Tours leave from the Stephen Robert ’62 Campus Center located at 75 Waterman Street.

Brown School of Engineering Hosts Eastman Conference

The Brown University School of Engineering is hosting the 2012 Lester Eastman Conference on High Performance Devices from August 7-9, 2012. The conference will include sessions on green technology; high speed devices; infrared photonics; terahertz technology; power conversion, switching, and transmission; and next generation devices.

The conference will have three plenary speakers: Professor Umesh Mishra (USCB) on Recent Advances in High Frequency Semiconductor Devices; Professor Hideo Ohno (Tohoku Univ., Japan) on Spintronic Devices for VLSI; and Dr. Kamiar Karimi (Boeing Corporation) on High Power Semiconductor Devices.

Larry Larson, Dean of the School of Engineering at Brown, will give a talk on the “Internet of Things”.

The conference is being organized locally by Domenico Pacifici, assistant professor of engineering at Brown. The general chair of the conference is Professor Paul Chow of RPI.

For more information, please go to: http://www.leconf.com/

Do girls need lacrosse helmets?

Joseph Crisco, professor of orthopaedics, wanted to measure the impact of hits to the head in girls’ lacrosse. He invited some players into his lab to take some shots at a test dummy. The data could inform an eventual standard for girls’ and women’s lacrosse.

A little more to the left
To analyze what happens in a girls' lacrosse game when
stick meets head, Joseph Crisco equipped a test dummy
with accelerometers and invited players to take some shots.
Credit: Mike Cohea/Brown University

PROVIDENCE, R.I. [Brown University] — Dr. Joseph "Trey" Crisco, the Henry F. Lippitt Professor of Orthopaedics and Director of the Bioengineering Lab, recently invited female lacrosse players ranging in age from 12 to 28 into his Rhode Island Hospital lab to swing their sticks for a project titled “Head Accelerations from Various Stick Checks in Girls’ Lacrosse.”

The research, funded by US Lacrosse, the national governing body of men’s, women’s and youth lacrosse, and by the National Operating Committee on Standards for Athletic Equipment, will provide data on how the head is accelerated after being hit by a stick. Video analysis of players taking whacks at a helmeted dummy, taken at 1,000 frames per second, could inform an eventual standard for girls’ and women’s lacrosse headgear.

For years, Crisco has studied head impacts in sports such as football, hockey, and lacrosse by embedding accelerometers in the helmets of collegiate teams and gathering data from actual practices and competition.

by David Orenstein

Quantifying the magnetic nature of light emission

In collaboration with The Institute of Photonics Sciences (ICFO) in Barcelona, Brown School of Engineering researchers in the lab of Rashid Zia ’01, Manning Assistant Professor of Engineering, have just published an article in in Nature Communications. Visiting scholar Tim Taminiau from the lab of Niek van Hulst at ICFO worked alongside Brown engineering graduate student Sinan Karaveli to demonstrate how the natural magnetic dipole transitions in lanthanide ions can be used to access optical-frequency magnetic fields.

Authors: Tim H. Taminiau, Sinan Karaveli, Niek F. van Hulst, and Rashid Zia

Examining how light emission is distributed in energy-
and momentum-space can reveal fundamental
information about optical transitions. This image
shows an energy-momentum spectrum of europium ions.
Following bright emissions lines, you may notice
several points where the contrast inverts - these
changes are direct visualizations of the opposite
symmetries of electric and magnetic dipoles transitions.

Abstract:
Tremendous advances in the study of magnetic light-matter interactions have recently been achieved using man-made nanostructures that exhibit and exploit an optical magnetic response. However, naturally occurring emitters can also exhibit magnetic resonances in the form of optical-frequency magnetic-dipole transitions. Here we quantify the magnetic nature of light emission using energy- and momentum-resolved spectroscopy, and leverage a pair of spectrally close electric- and magnetic-dipole transitions in trivalent europium to probe vacuum fluctuations in the electric and magnetic fields at the nanometre scale. These results reveal a new tool for nano-optics: an atomic-size quantum emitter that interacts with the magnetic component of light.

To access the full article, please go to:
http://www.nature.com/ncomms/journal/v3/n7/full/ncomms1984.html

Venture for America fellow Tim Dingman '11 hired by Accio Energy

Accio Energy (Ann Arbor, Mich.) is taking on one of the first Venture for America fellows this month, hiring Tim Dingman '11, an electrical engineering graduate from Brown University.

Venture for America is launching its inaugural class of fellows this summer, pairing 40 fresh college graduates with start-ups in economically challenged regions. The New York City-based non-profit is modeled after Teach for America where it pairs top talent from U.S. universities with innovative start-ups growing in urban areas, such as New Orleans, Las Vegas, Cincinnati and Providence, Rhode Island. The idea is to give college grads an open door into entrepreneurship in the hopes they will launch their own start-ups in their host cities one day.

Metro Detroit companies are receiving 11 of these fellows, and Accio Energy is the only firm from Ann Arbor to receive one. The alternative energy start-up is reinventing the wind energy generation with new technology that creates clean energy from static electricity generated from the wind.

"The novelty of it combined with the size of the company were two huge draws," says Dingman.

Dingman also founded his own start-up, which makes a showerhead efficiency upgrade for dorm rooms. He has been interested in developing clean tech for most if his college career, but wanted to get his professional start working for a young company creating disruptive technology.

"There is a lot of energy there," Dingman says. "There is a lot of room for innovation which is what I was looking for in my placement."

Source: Tim Dingman, fellow with Venture for America
Writer: Jon Zemke

Joseph Calo Named a Fellow of the American Chemical Society

Joseph Calo, Professor Emeritus at the Brown School of Engineering, has been named a Fellow of the American Chemical Society (ACS). Calo is one of 96 fellows in the 2012 class and will be honored at the society’s national meeting in Philadelphia in August.

A founder of the chemical engineering program at Brown, Calo was honored for his research contributions in chemical kinetics and transport phenomena as applied to carbon materials, environmental characterization/remediation, and energy conversion.

He served as treasurer, councilor, technical program secretary and representative of the Fuel Chemistry (now Energy and Fuels, ENFL) Division to the Multidisciplinary Program Planning Group (MPPG), and Divisional Activities Committee (DAC) member of ACS.

"I'd like to congratulate Professor Calo on this spectacular achievement,” said Dean Larry Larson. “Becoming a Fellow of the ACS is a recognition of a lifetime of technical contributions and service to the American Chemical Society. Professor Calo's contributions to Brown and to Chemical Engineering have been and continue to be extraordinary."

The fellows program began in 2009 as a way to recognize and honor ACS members for outstanding achievements in and contributions to science, the profession, and ACS.

LEGO robots make great teachers

A partnership between Brown’s Science Center and the Paul Cuffee Middle School gave 10 young student hands-on instruction in the finer points of computer programming and engineering using LEGO® robots as the teaching tool. Brown engineering students Raymon Baek '14 and Michael Lazos '15 were the instructors for the program.

PROVIDENCE, R.I. [Brown University] — Like sumo wrestlers, two LEGO® robots made their way around an oval ring, grabbing, swatting at each other, and trying with great gusto to push the other robot out of the ring to win the match. Ten young boys — third, fourth, and fifth graders — at the Paul Cuffee Middle School in Providence cheered on their creations, watching in delight as their aggressor responded to pre-programmed commands and light sensors to make their way around the ring in pursuit of the opponent. At each turn, parents and volunteer instructors joined in the cheering at the school’s cafeteria on Friday, July 20th. It was the culmination of a three-week pilot program designed to pique children’s interest in engineering and computer science.

Building a sumo warrior block by block
LEGO® programmers, from left, Aidan Marinelli, Jose Pagan,
and Luke Taylor watch as their team's robot is attacked
by a competitor. It was a sumo-style robotic battle.
Credit: All photos by Mike Cohea/Brown University 

The LEGO® robotic program was a partnership between Brown’s Science Center and the Paul Cuffee Middle School. Ten student participants were divided into two teams — the Panthers and the Demons of Nothingness — and instructed in the finer points of computer programming and engineering using LEGO® robots as the teaching tool. Students used a kit that not only contained LEGO® pieces but robots’ “brains,” which were connected to laptops so students could program the brains to respond to light, touch, ultrasonic, sound, color, temperature, accelerometer, compass, and radio-frequency identification sensors.

Brown students Mike Lazos, a computer engineering concentrator, and Raymon Baek, whose concentration is in mechanical engineering, helped the students design, build and program robots for four hours every day during the three-week summer program. According to instructor Baek the program was a tremendous success.

“The kids were very bright and went beyond our expectations,” Baek said. “We always finished the planned curriculum a lot quicker than expected, which kept Mike and me improvising to stay ahead of the students.”

Keeping a step ahead
Instructors Raymon Baek, left, and Michael Lazos
were surprised at how quickly students mastered
material. In the final battle, the instructors’ own
robot was thrown for a loss.

The students used visual programming software with easily readable icons and distinct colors for each type of tile. For example, movement tiles would tell the robot to move and sensor tiles would tell the program to rely on a specific sensor. The program used wait statements (e.g., wait for a certain sound level or touch sensor to be activated), switch statements (e.g., if the light sensor detects a dark area, move right; move left for a bright area), and loops. These commands made it possible for the robots to compete in the sumo wrestling challenge and an obstacle course.

The students had to be creative about using sensors to follow a zigzag path through the obstacle course, navigating through various boxes, capturing colored balls from a central area, and bringing them back to their starting points. The Panthers easily won the obstacle course because they built a robot that had a robotic arm that pulled nearly all the balls back to its starting point in one trial.

To the victor, the spoils
The robot designed by the Demons of Nothingness
outlasted all competitors.

As for the battle arena, the Demons of Nothingness won because their robot was very bulky and stable. “Mike and I decided to surprise them by introducing our own robot that we assumed was invincible,” said Baek. “We had the three robots fight it out in the ring. To our surprise, our robot was pushed out of the ring and the Demons of Nothingness reigned victorious.”

During the three-week program, the instructors gained some insight about the challenges of teaching. “The boys loved to build, but the programming, which required them to sit still and concentrate was a challenge. They need to get up and run around every so often to burn off some energy,” said Baek.

In this pilot effort, all participants including the students, teachers, learning concept, and execution proved to be a perfect match.

Brown conducts helmet study for girls lacrosse

Joseph "Trey" Crisco, Henry Frederick Lippitt Professor of Orthopaedic Research and Director of the Bioengineering Lab, who has done pioneering research with concussions and football helmets is now studying girl's and women's lacrosse, which does not require helmets. 

Crash-test dummies subjected to a barrage of sticks to the head may help settle the debate over whether helmets should be required in girl's lacrosse.

There has been increased concern over concussions in a sport that prohibits the use of hard helmets, while soft headgear in the girls' game is allowed. Hard helmets are required in the men's version of the game.

Brown University in Rhode Island will conduct a study during the third week of July to try to determine whether helmets will help protect girls from concussions caused by stick-to-head contact, and if so, what type.

"Right now, there is no standard for head protection in the women's game," said Ann Kitt Carpenetti, the managing director of game administration for US Lacrosse, the sport's governing body. "There is an allowance in our rules for soft headgear, but no testing has been done and little or no research."

The issue of requiring helmets in girl's lacrosse, at the high school and college levels, remains a hot-button issue. Many of the players and coaches fear that mandatory helmet use, especially of the hard-shell variety, would make their sport too physical and more like the boys game. But some in the medical profession are fearful of the danger of concussions and are in favor of required helmet use.

Females use more 'finesse'

"The girls' sport was meant to be a finesse sport, an athletic sport, and not a power sport or a brute-force sport," said Shoreham-Wading River coach Mary Ann Bergmann. "US Lacrosse and the referees' associations need to come together and figure out what's best for the sport."

Long Island, which has about 2,000 girls playing lacrosse on 104 high school teams, was the focus of the debate last spring, when Alexandra Fehmel, a star player on Bergmann's team, began playing with a soft helmet designed by a family friend. Before wearing the soft helmet, Fehmel had suffered two concussions playing lacrosse.

Fehmel, whose team won the Class C state championship in June, said wearing the soft helmet "has definitely helped me with my confidence. It protects me from stick-to-head injuries and any concussion I might get from that. I'm not scared to go to goal anymore. I'm not afraid to be aggressive."

Could the results of this summer's testing be the first step toward requiring helmets?

"I would not say that helmet use is inevitable. I would say that what's inevitable is that there will be a standard, hopefully by next year," said Carpenetti.

She said that US Lacrosse, in conjunction with the National Operating Committee on Standards for Athletic Equipment, which established national standards for football and baseball helmets, has funded the research project at Brown.

Project director Joseph "Trey" Crisco, a professor of orthopedics at Brown, said his study's goal "is to try to understand what head accelerations girls receive during games. How hard is the head being impacted by ball or stick?"

He said he had hoped to use sensors to measure that impact, but there was no place to effectively attach the sensors on players' heads.

"So we decided to use dummies, like they use in car crash simulations," Crisco said. "We have a model and we will have girls lacrosse players from the [Rhode Island] area come into our lab and whack away from different angles. They'll be whacking on the top of the 'head' and the side of the 'head.' They'll use the tip, the shaft and the middle of the stick so we can determine the severity of stick checks."

Crisco noted that the head forms are gender-neutral, "but they do have sizes, and we're using the smaller size."

Crisco said that once the data is compiled, "it will help US Lacrosse determine the type of helmets or whether there is even a need for them."

Crisco said results will require four to six weeks to be analyzed, and he estimates it will take several months before the report is ready.

One player's decision

For Fehmel, the question of requiring helmets has already been answered. She said she favors requiring soft helmets but not hard ones.

"Hard helmets would hurt players even more, just from bumping into each other," she said.

Bergmann, who currently is playing lacrosse in Europe where no headgear is worn, said she isn't sure where she stands on the issue of helmets.

"If you give everyone helmets, is the game going to become more aggressive?" she asked. "That's why I'm still in between."

Dr. Karl Friedman, Nassau County's supervising physician for football and lacrosse championships, is not a helmet advocate. "We don't need the helmet," he said. "We don't want to change the game. . . . The more equipment you put on them, the more you can let them play because now the safety is covered by the equipment. Absolutely they'll be more careless with their sticks . They'll be more fearless and the referees will loosen up."

Getting a second opinion

However, there are those in the medical community who feel strongly that hard-shell, boys-style lacrosse helmets are not only essential in the girls' game, but inevitable.

"When rules for girls lacrosse were written, they were written to keep the ball and stick out of the sphere of the head," said Dr. Jack Marzec, team physician for West Islip and East Islip high schools and consulting orthopedic physician for the Long Island Lizards professional men's lacrosse team.

"Girls are getting quicker, stronger, more aggressive," he added. "They're looking for scholarships and they want to win, just like the boys. I am adamant that hard helmets must be instituted in girls lacrosse because it's impossible to keep the stick and ball off the head."

Nationally known concussion expert Dr. Micky Collins, of the University of Pittsburgh Medical Center, said he can't make up his mind whether requiring female players to wear helmets is a good idea.

"I'm sitting on the fence," he said. "We know girls are more at risk for concussions. . . . There are a lot of issues on the table here. The only way to answer these questions is to do the research and find out, scientifically, where we're at. There is no good science leading us right now."

Originally published in Newsday
by Bob Herzog
with Stephen Haynes and James Crepea

RULES FOR GIRLS

Players must wear a mouthpiece and protective goggles. They may wear a soft padded helmet but not hard-shell headgear.

Checking is permitted on the head of the lacrosse stick only.

No deep pocket in the stick is allowed. No mesh pockets.

Length of stick is the same for all field players (typically 42 inches).

Played with 12 members on each team: a goalie, five defensive players and six attack players.

At least five players must remain on the defensive side of the field and four on the offensive side at all times.

Shooting is permitted only when pathway to goal is clear.

Defenders cannot block an attacker's pathway to shoot on goal unless they are within one stick-length of the attacker.

Cannot shoot a loose, uncontrolled ball; cannot hit another player with the ball; cannot hit the goalie in the head with the ball.

RULES FOR BOYS

Players must wear a hard-shell helmet with face guard.

Stick-to-body contact is integral to the game.

Checking is permitted anywhere on the stick.

Pockets in sticks are allowed because of the checking.

The length of the stick is different for different positions.

Played with 10 members on each team: a goalie, three defenders, three midfielders and three attackmen.

At least four players must remain on the defensive side of the field and three on the offensive side at all times.

Players may shoot at anytime.

Students demand entrepreneurship training

Clyde Briant, professor of engineering and vice president for research, was in Washington, D.C., on July 11 for a media roundtable hosted by The Science Coalition. Innovation and entrepreneurship was a hot topic. Below is an excerpt from Briant’s answer to the question, “Are we as a nation doing enough as a nation to inspire, prepare and develop the next generation of innovators?” An MP3 recording of the session is available online.

At Brown we have the famous open curriculum – it’s still called the new curriculum even though it started in 1969 – where the students have a tremendous amount of freedom in building up what they are going to take. We attract a cohort of entrepreneurial students. We do have an entrepreneurship program. It’s a student-led organization that’s extremely active, and one I’ve worked with in various ways through the years. I’d guess it’s about eight or nine years ago, really out of student demand, [that] we started a new major — a concentration as we call it — called Commerce, Organizations and Entrepreneurship. We don’t have a business school, but we pulled together engineering, sociology, and economics to launch this new undergraduate concentration. It certainly is one of the biggest concentrations now in a very short time because students feel that they do get experiential learning, they do get a chance to prepare themselves for a career in entrepreneurship. It’s been an extremely successful program for us.

Venture training helps entrepreneurs succeed

Venture for America's first class of 40 fellows, including engineering alumnus Tim Dingman '11, is currently on the Brown campus for the program's inaugural five-week training camp. Founded in 2011 by Brown alum Andrew Yang, the program places recent college graduates who have aspirations for entrepreneurship into two-year apprenticeships at startup and early stage companies in economically challenged cities around the country. In the fall, the first class of fellows will be headed to jobs in New Orleans, Las Vegas, Cincinnati, Detroit, and Providence.

PROVIDENCE, R.I. [Brown University] — For many young people, the way forward after college leads from the classroom to the corporate office, often with a stop at law or business school. But Andrew Yang knew that life after college didn’t have to follow a well-worn path; it was just a matter of making sure recent graduates knew about other options available to them. Seeking to do just that, Yang founded Venture for America, a fellowship program that pairs recent graduates with startups and early stage companies, in the summer of 2011.

Helping startups help host cities
By matching recent well-trained college graduates with
startups and early stage companies, Venture for America
hopes to help the economies of financially strained cities.

Based on the Teach for America model, Venture for America fellows complete two-year apprenticeships with companies in economically challenged cities. Working in a small company, fellows can help to grow the business while also gaining valuable real-world skills and experience. Yang also hopes that the model will have an economic impact on the cities where the partnering companies are located. “Early stage companies are where job growth and innovation are going to come from.”

Yang says it may take a few years for the effects to be obvious. “This year we’ll send five students to a city, but next year it might be 10 and then 10 again the next year. By then, the first group of students will be starting companies, and they will hire some from the next group. It’s a long-term plan to help these economies; there aren’t any quick fixes,” Yang says.

Before heading off to their respective cities, Venture for America fellows take part in a five-week training camp that prepares them for their new jobs.

Since mid-June, the first class of 40 fellows has been on the Brown campus, taking part in the program’s inaugural training camp. Each day they gather on the third floor of Pembroke Hall for a day filled with lectures and lessons by an impressive roster of industry experts — McInsey and Ideo are two of the companies taking part — followed by skill development, with small groups completing tasks such as creating a business model or programming a computer.

In September, they’ll head off to five cities around the country — New Orleans, Las Vegas, Cincinatti, Detroit, and Providence — to begin their apprenticeships. Four fellows talked about what they’re learning from the program and where they’re headed in the fall:

---

Tim Dingman graduated from Brown in the spring of 2011 and was entering the fifth-year master’s in engineering program when he began to think about what he’d do when he got out of school. As an organizer of the A Better World By Design conference for two years, he had realized that a lifetime in the research lab wasn’t for him: “I always felt there was a large disconnect between what was happening in the lab and what was happening in the real world where you can make the biggest immediate impact.” So when he found out about Venture for America, he knew immediately that the program would give him that dual outlet that he needed. In the fall, he’s headed to Detroit to work for Accio Energy, an early stage company that works on harvesting wind energy by giving an electrical charge to water droplets.

Dingman says that the training camp is giving him a wide range of skills to take with him to his new job, most notably the ability to be more open to feedback. “It seems intimidating to give someone very specific and personal feedback, but I’ve realized that in fact, it’s something to be encouraged and embraced to have a fully function team.”

---

Scott Lowe had two specific criteria in his search for a job after graduating from the University of Oklahoma in 2012: “I wanted something intellectually stimulating but also high impact.” A program at his alma mater that had him working on commercializing technologies developed by University of Oklahoma faculty helped him realize that he also had an interest in entrepreneurship. So when a friend told him about Venture for America, it sounded like the perfect fit. The aspiring CEO says the training camp is providing valuable lessons he’ll be able to put toward his future goals. “I’m viewing this as CEO training. A CEO doesn’t have to know a lot about any one thing but needs to know a little bit about every aspect of the company, from finance to sending e-mails effectively. I think they’re doing a great job of CEO training.”

Headed to Detroit in the fall to work as a software analyst at Digerati, Lowe hopes to wear many hats during his apprenticeship. And while the transition from his small Oklahoma town to a very large city will no doubt take some getting used to, Lowe says he’s excited for the potential Detroit has to offer. “One of the fellows, Derek Turner, has a great quote: ‘There are empty skyscrapers (in Detroit). Where else would you want to start a business?’ I think that really speaks to why I’m excited.”

---

Melanie Freidrichs won’t have far to go when she begins her apprenticeship this fall. The 2012 Brown graduate will be heading down the hill to Providence-based Andera, an early stage company that creates software for small banking companies. It’s an ideal assignment for Freidrichs, who hopes to remain in the industry for the long term. “It’s an area that has been on the forefront of technology in many ways, but I do think there is a long way to go in terms of mobile banking and mobile payments and seeing what can be done to play with the traditional banking model to make that information easier to understand and more accessible for everyone.”

Freidrichs says she’s thankful for all of the technical skills she’s acquiring in the training camp, such as programming and Java, which will serve her well at her new job. She says she also appreciates the balance of startup and corporate perspectives that has been offered, despite Venture for America’s primarily small-business focus. “I don’t feel that the best entrepreneurs are the one’s that get caught up in being super startupy. I’m trying to look at what influences I can take from big business versus the startup world to be the best entrepreneur.”

---

When Michael Mayer was preparing to graduate from the Wharton School of the University of Pennsylvania in 2012, he turned to family and friends for guidance. Many of them had had success in banking, so Mayer chose a similar path, starting out as an intern for Credit Suisse the summer before his senior year. But when the company offered him a job, he turned it down. “I had an incredible summer, but the day-to-day in banking was not something I could get behind and get passionate about,” Mayer says. He confesses that he was initially nervous about his decision, but when he stumbled upon Venture for America, he knew he’d made the right choice. “It was kind of love at first sight,” Mayer says.

One aspect of the program that attracted him has the community outreach component. “You’re going to these places that need help, and not only are you helping to grow a business and enhance the local economy, but you’re also there to mentor kids at high schools or start some kind of social program to help people connect, so there’s a whole different aspect that you don’t get working at a startup elsewhere.” Mayer will be able to put that philanthropic spirit to good use in New Orleans, where he’ll be working for market research technology firm Federated Sample. Where he goes after his apprenticeship, he’s unsure, but he’s certain that he’ll value and use the network of fellows he’s met at the training camp for many years. “When I have a business idea, the first people I’m going to call are the fellows. While we’re here, we’re throwing out ideas left and right, giving constructive criticism and helping each other out, so we’re all going to be close and comfortable talking about our new ideas later on. I’m so excited to see what the future holds.”

Professor Nitin Padture Named Director of Center for Advanced Materials Research

Brown University School of Engineering Professor Nitin Padture, Professor of Engineering, has agreed to become the new director of the Center for Advanced Materials Research (CAMR).

“I want to thank Professor Padture for taking on this important leadership position at Brown and the School of Engineering,” said Larry Larson, Dean of Engineering. “Since arriving earlier this year, Professor Padture has demonstrated amazing resourcefulness in building up a world-leading research program in a short period of time. We will all benefit from his energetic direction as the new director of the Center for Advanced Materials Research (CAMR).”

Padture joined the Brown faculty in January of 2012. Previously he was College of Engineering Distinguished Professor at The Ohio State University, and also the founding director of the NSF-funded Materials Research Science and Engineering Center (MRSEC) at OSU.

“At Brown he has already made important contributions to IMNI [Institute for Molecular and Nanoscale Innovation] and to CAMR,” said Clyde Briant, Vice President for Research.

“I am deeply honored to have the chance to serve the vibrant materials community at Brown, and I hope to create an environment that fosters interdisciplinary material research of the highest quality and impact,” said Padture.

Padture received B.Tech. in metallurgical engineering from Indian Institute of Technology, Bombay (1985), M.S. in ceramic engineering from Alfred University (1987), and Ph.D. in materials science and engineering from Lehigh University (1991).

He was a postdoctoral fellow at the National Institute of Standards and Technology (NIST) for three years, before joining the University of Connecticut faculty in January 1995 as an assistant professor. He became an associate professor in 1998 and was promoted to professor in 2003. He served as interim department head at UConn before moving to Ohio State in January 2005.

Padture’s teaching and research interests are in the broad areas of synthesis/processing and properties of advanced materials used in applications ranging from jet engines to computer chips, impacting transportation, energy, and information technology sectors. Specifically, he has active research in tailoring of structural ceramic, composites, and coatings, and functional nanomaterials including graphene and perovskites.

Padture has published over 120 journal papers, which have been cited about 5,000 times. Padture is a co-inventor of four patents, and he has delivered some 150 invited/keynote/plenary talks in the U.S. and abroad. A fellow of the American Ceramic Society, he has received that society’s Roland B. Snow, Robert L. Coble, and Richard M. Fulrath awards. Padture is also a recipient of the Office of Naval Research Young Investigator Award and a Fellow of the American Association for the Advancement of Science. Padture is a principal editor of Journal of Materials Research and an associate editor of Journal of the American Ceramic Society.

Multiple perspectives improve laparoscopy

Surgeons given their own view of a laparoscopic task, rather than a shared one, can work more efficiently and accurately, a small new study suggests. Findings from “proof of concept” experiments appear in the Journal of Laparoendoscopic and Advanced Surgical Techniques. Professor of Engineering Harvey Silverman helped to develop the system.

PROVIDENCE, R.I. [Brown University] — What makes laparoscopic surgery “minimally invasive” — instruments enter the patient through narrow tubes — also makes it visually constraining. As they work on different tasks, surgeons all see the same view. What if each surgeon could control a separate view best suited to the specific task? In a new paper, pediatric surgeon Dr. Francois Luks and his team of co-authors at Brown University and Hasbro Children’s Hospital report that in a small in vitro trial, surgeons with their own views performed faster and more accurately.

Individual views
Earlier work experimented with special googles that allowed
individual surgeons to hone in on their tasks, but goggles
isolated members of the surgical team. Individual views on
individual monitors appear to improve performance on
complex surgical tasks.
Credit: Francois Luks/Brown University

“When we perform regular surgery, there is more than one point of view,” said Luks, professor of surgery in the Warren Alpert Medical School of Brown University. “If I’m operating with somebody on an open case, I can focus on one aspect of the wound while my assistant can focus on something else. I can cut a suture while he starts the next. We can never do that with laparoscopy, because it is only a single image.”

For Luks and his colleagues the idea of giving each surgeon control of his or her own point of view during laparoscopic surgery has emerged as a key step toward making laparoscopic surgery feel more like open surgery.

Does it do any good?

A natural question, however, is whether doing so would produce the assumed performance improvement. The small “proof-of-concept” experiments in the new paper, published online June 25 in the Journal of Laparoendoscopic and Advanced Surgical Techniques, were meant to begin answering that. First author Dr. Rajan Thakkar, a surgical resident at Brown University and Rhode Island Hospital, presented the results earlier this year at the IPEG 2012 conference.

Different parts of the whole
A single laparoscope delivers an image that is large enough
to allow each surgeon a highly detailed separate view
optimized for the surgical task.

To conduct the study, Luks’ team gathered 20 surgeons of different experience levels to take on two standardized training tasks. The volunteers were paired in teams of similar experience (e.g., two novices or two experts). Gazing at wall-mounted monitors, each pair would perform each task once using a shared view from one camera and once using individual laparoscopes and therefore their own individually controlled images. The order in which each pair performed the tasks was determined randomly.

The research team meanwhile measured the speed and accuracy of each pair’s performance as they worked.

For the first task, one surgeon had to pluck each of 10 beads, one by one, out of a small dish and pass it in mid-air to the partner who had to then place it atop a peg. The novice pairs did not show any improvement in speed using individual views versus a shared view, taking about 600 seconds to accomplish the task in each case. Experts, however, sped up considerably, reducing the task time to 245 seconds on average using individual views, compared to 409 seconds with the shared view.

The second task involved threading a suture around a rubber band and around some pegs. The band would topple if one surgeon didn’t control the tension on the suture that the other created while pulling it around the pegs. On this task, both novice and expert pairs improved markedly with individual views. Novice pairs with individual views did the task in 53.5 seconds on average compared to 90.5 seconds when they had to share a view. Experts did the job in 49 seconds with individual views but 71.7 seconds with the shared view. Individualized viewing also reduced the number of times a rubber band was knocked down.

One camera, individual views

In practice, a surgical team uses only one laparoscope, not two, and so there would be only one image to work from. In previous research the team has shown how software can isolate individually useful views from within a single image.

In 2009 in the same journal, Luks and a team including current co-author Dr. Jeremy Aidlen, described an electronic goggle system called i-LID that offered wearers a unique view from within one image that they could control simply by moving their head to look around or zoom in and out. Given a large, high-resolution image from the laparoscopic camera, software simply carved out the portions that each surgeon indicated interest in based on head movement. The team worked with engineers including Harvey Silverman, professor of engineering at Brown, to develop the system.

The idea had some drawbacks, however. For one thing, goggles isolate surgeons from each other, Luks said. Also wireless transmission of the high-definition image to each pair of goggles could create latency, and while versions with wires had faster data speeds, they had the potential to be physically imposing in the close quarters of surgery.

But now Luks and Aidlen are encouraged both by the new results indicating that individual views could help surgical teams perform better, and by Aidlen’s grant from the Rhode Island Foundation to develop an automated system that delivers individual control of views from within the same image, but does so without isolating goggle control.

That next innovation, and more testing, will move them closer to bringing individually controllable views and their apparent benefits into the operating room.

Luks and Aidlen are the senior authors. The paper’s second author is Dr. Shaun Steigman, fellow in pediatric surgery at Hasbro Hospital and Brown University.

- by David Orenstein

Professor David Cooper Honored at CVPR Conference

David Cooper, Professor Emeritus of Engineering and Professor of Engineering (Research), was honored at the 25th International IEEE (Institute of Electrical and Electronics Engineers) Conference on Computer Vision and Pattern Recognition (CVPR) which was held in Providence from June 18-20. This is the major annual meeting on CVPR. Professor Cooper was honored “In appreciation of his outstanding and pioneering contributions to Unsupervised Learning and Bayesian Inference in Computer Vision.” The international conference was held this year at the Convention Center with over 1800 attendees. Brown University Professor Benjamin Kimia served as one of three general co-chairs of the conference.

Ben Kimia, David Cooper, Rama Chellappa

Professor Cooper’s current research focuses on the development and application of new geometric, algebraic, and probabilistic approaches, models, and algorithms for recognizing and estimating 2D and 3D geometric information and functioning in 3D scenes from images, video, and range data.

Professor Cooper received both his Sc.B. and Sc.M. degrees from MIT in electrical engineering, and his Ph.D. from Columbia University in applied mathematics. After graduation, he joined the Brown faculty in September of 1966 as an assistant professor. He became an associate professor in 1969, and was promoted to full professor in 1978. During his more than 45 years at Brown, Cooper has also served as cofounder and associate director of the Laboratory for Engineering Man/Machine Systems (LEMS) for more than 15 years, and the head of electrical engineering for two years. He is a fellow of the IEEE and has published roughly 140 papers in refereed journals or as book chapters.

For more information on the CVPR awards, please go to: http://www.cvpr2012.org/program-details/awards

Fei Guo Ph.D. ’12 Receives Brian Kelly Award

Brown University School of Engineering postdoctoral researcher Fei Guo Ph.D. ’12 was presented the Brian Kelly Award at Carbon 2012, the annual world conference on carbon in Krakow, Poland, on June 21. Guo, who was advised by Professor Bob Hurt at Brown, delivered a 30-minute award lecture, “Graphene-Based Environmental Barriers,” to the conference participants.

In his presentation, Guo demonstrated the potential for graphene oxide films to act as high-performance barriers for environmental toxicants. Applying elemental mercury (considered a neurotoxic) as a model, he showed that just 20 nm graphene oxide films, which were deposited onto surface treated polymers, reduced mercury permeability by 90%.

This prestigious annual award was established in 1996 by the British Carbon Group in memory of Brian Kelly, a leading authority on the physics of graphite to reward excellence in carbon science and technology. The award is currently five hundred pounds sterling (£500) and was presented at the time of the conference with a certificate. The award is intended as a travel grant for students and early career researchers with up to ten years postdoctoral experience to attend the annual World Carbon Conference.

Selenium controls staph on implant material

A coating of selenium nanoparticles significantly reduces the growth of Staphylococcus aureus on polycarbonate, a material common in implanted devices such as catheters and endotracheal tubes, engineers at Brown University report in a new study.

PROVIDENCE, R.I. [Brown University] — Selenium is an inexpensive element that naturally belongs in the body. It is also known to combat bacteria. Still, it had not been tried as an antibiotic coating on a medical device material. In a new study, Brown University engineers report that when they used selenium nanoparticles to coat polycarbonate, the material of catheters and endotracheal tubes, the results were significant reductions in cultured populations of Staphylococcus aureus bacteria, sometimes by as much as 90 percent.

Selenium solutionQi Wang swirls a solution of selenium nanoparticles in the lab.
Coatings of the nanoparticles appear effective in fighting staph
bacteria in medical device materials, according to a new study.
Credit: Webster Lab/Brown University

“We want to keep the bacteria from generating a biofilm,” said Thomas Webster, professor of engineering and orthopaedics, who studies how nanotechnology can improve medical implants. He is the senior author of the paper, published online this week in the Journal of Biomedical Materials Research A.

Biofilms are notoriously tough colonies of bacteria to treat because they are often able to resist antibiotic drugs.

“The longer we can delay or inhibit completely the formation of these colonies, the more likely your immune system will clear them,” Webster said. “Putting selenium on there could buy more time to keep an endotracheal tube in a patient.”

Meanwhile, Webster said, because selenium is actually a recommended nutrient, it should be harmless in the body at the concentrations found in the coatings. Also, it is much less expensive than silver, a less biocompatible material that is the current state of the art for antibacterial medical device coatings.

Webster has been investigating selenium nanoparticles for years, mostly for their possible anticancer effects. As he began to look at their antibiotic properties, he consulted with Hasbro Children’s Hospital pediatrician Keiko Tarquinio, assistant professor of pediatrics, who has been eager to find ways to reduce biofilms on implants.

Studying selenium

For this study, Webster and first author Qi Wang grew selenium nanoparticles of two different size ranges and then used solutions of them to coat pieces of polycarbonate using a quick, simple process. On some of the polycarbonate, they then applied and ripped off tape not only to test the durability of the coatings but also to see how a degraded concentration of selenium would perform against bacteria.

On coated polycarbonate — both the originally coated and the tape-tested pieces — Wang and Webster used electron and atomic force microscopes to measure the concentration of nanoparticles and how much surface area of selenium was exposed to interact with bacteria.

One of their findings was that after the tape test, smaller nanoparticles adhered better to the polycarbonate than larger ones.

Then they were ready for the key step: experiments that exposed cultured staph bacteria to polycarbonate pieces, some of which were left uncoated as controls. Among the coated pieces, some had the larger nanoparticles and some had the smaller ones. Some from each of those groups had been degraded by the tape, and others had not.

All four types of selenium coatings proved effective in reducing staph populations after 24, 48, and 72 hours compared to the uncoated controls. The most potent effects — reductions larger than 90 percent after 24 hours and as much as 85 percent after 72 hours — came from coatings of either particle size range that had not been degraded by the tape. Among those coatings that had been subjected to the tape test, the smaller nanoparticle coatings proved more effective.

Staph populations exposed to any of the coated polycarbonate pieces peaked at the 48-hour timeframe, perhaps because that is when the bacteria could take fullest advantage of the in vitro culture medium. But levels always fell back dramatically by 72 hours.

The next step, Webster said, is to begin testing in animals. Such in vivo experiments, he said, will test the selenium coatings in a context where the bacteria have more available food but will also face an immune system response.

The results may ultimately have commercial relevance. Former graduate students developed a business plan for the selenium nanoparticle coatings while in school and have since licensed the technology from Brown for their company, Axena Technologies.

Small Wonder

Partnering with an engineer, a pathologist goes in a new direction.

The yellow-and-black signs outside Dr. Agnes Kane’s pathology laboratory read “CAUTION: Cancer hazard.” Nodding at the ominous-looking postings, Kane explains, “because of their toxicity similar to asbestos, we handle these materials as if they were carcinogens.” Meanwhile, across the Providence River, at the School of Engineering, Professor Robert Hurt is hard at work creating the very materials that Kane is so gingerly studying: nanoparticles.

Smaller than 1,000th the width of a human hair—so small that you need an electron microscope to see them— nanoparticles’ practical applications may be enormous: making implants more biocompatible; diagnosing and treating cancers; cleaning up oil spills. That said, the history of science is filled with promising solutions that create additional unforeseen problems of their own. No one is more aware of this than Kane, chair of Brown’s Department of Pathology and Laboratory Medicine. She has spent her career on, and helped guide the Department’s focus on, the human health effects of environmental and occupational exposures. She and Hurt tick off some examples demonstrating this law of unintended consequences:

“Corn ethanol,” says Hurt, referring to the fact that 40 percent of the corn grown in America is used to create this alternative fuel. “Then you raise the corn prices for food.”

Kane nods. “Use more fertilizer? Contaminate our water supplies. There’s always these trade-offs.”

One of modern history’s most devastating trade-offs was of a common mineral that makes an excellent flameretardant building material. Its usefulness notwithstanding, asbestos can cause devastating cancers and fatal lung problems both for those who mine it and for those who live and work in buildings that contain it.

Small, Novel...but Safe

Selenium-carbon nanocomposite particles
synthesized as a novel chemotherapy agent

From the time Kane joined Brown’s pathology department as a founding member in 1982, she has studied the mechanisms by which asbestos injures cells and causes cancer. When, in 2004, she gave a talk about this research to a group of colleagues, Hurt approached her afterward. The asbestos fibers that Kane showed in her talk reminded Hurt of the carbon nanofibers he had been developing. “We were not working on health effects at the time,” Hurt says. “We were doing traditional nanoscience, trying to make new things that had never been made before.”

But when Hurt told Kane about his carbon nanofibers, “I immediately asked him if I could have some,” Kane recalls. Her worrisome discovery—that the particles were similar to asbestos in several key ways—has changed the direction of both her own and Hurt’s careers and of the pathology department’s research and teaching.

Now Kane and Hunt work side-by-side to create innovative nanotechnology and, simultaneously, assess the materials’ safety and toxicity. “It’s a new paradigm to try to consider the implications of the technology as you develop the technology,” says Hurt. “We haven’t done a lot of that in the past. We just develop technology and we field it and then we worry about what its implications might be. So it’s kind of fun to do these things together.”

In 2007, their collaboration gave rise to the Institute for Molecular and Nanoscale Innovation (IMNI), an interdisciplinary organization comprising more than 60 faculty in nine departments. Kane heads IMNI’s NanoHealth Initiative, which studies the environmental and health effects of nanotechnology.

Training the Next Interdisciplinarians

With curly chin-length gray hair and blue eyes, Kane—known to friends and colleagues as “Aggie”—smiles often and laughs readily. Her unassuming manner and commitment to collaboration, teaching, and mentorship have won her numerous teaching awards and devotees.

“If it weren’t for Aggie, I wouldn’t be doing what I’m doing,” says Luba Dumenco, a lecturer in pathology and director of the Medical School’s preclinical curriculum. “She’s always valued teaching incredibly highly.” Just recently, Dumenco struck up a conversation with another mom at the local skating rink.The woman happened to be a neonatologist who had trained at Brown’s medical school. “I told her I was teaching at the med school, and she said, ‘Do you know Dr. Aggie Kane? She was our favorite! We loved her!’” Dumenco says with a laugh. “She cares a lot about the students.She does a wonderful job and they’re very lucky to have her.”

The breadth of students that Kane reaches each year has grown as a result of her partnership with Hurt. In 2009, they secured a grant from GAANN, or Graduate Assistance in Areas of National Need, to fund interdisciplinary training in nanotechnology. Between six and eight doctoral students study nanotoxicology and nanomedicine with co-mentors in engineering or physical sciences and biological science. Kane and Hurt also co-teach an undergraduate and graduate course called “Small Wonders: Science, Technology, and Human Health Impacts of Nanomaterials.” For their final projects, students working together in interdisciplinary teams are required both to use nanotechnology to solve some real-world problem and to address—and minimize—their solution’s potential environmental and health impacts. “I look at this as training the next generation of environmental scientists and engineers,” Kane says.

But first they have to learn how to talk to each other. When Kane and Hurt began collaborating, “it took us a while to learn each other’s languages,” says Kane, “because medicine has its own vocabulary, as well as engineering.” Kane might, for example, say “mitochondria,” or “epigenetics,” and get a blank stare in return. “And so we would just keep asking each other questions, any time we didn’t understand something,” she recalls. “It took us quite some time to learn enough to communicate effectively.”

Their newest collaboration is funded by the Gulf of Mexico Research Initiative, which was established in the wake of the Deepwater Horizon disaster. Hurt has set out to design nanoparticles called nanosorbents, which by capturing and sequestering pollutants like oil, may be safer and more effective than existing methods of cleaning up oil spills. The Deepwater Horizon cleanup team—like the Exxon Valdez team before it—relied on Corexit, a dispersant which causes oil to suspend in the water as tiny particles rather than accumulate on the surface as oil slicks.

“They used it in enormous amounts in the Deepwater Horizon cleanup,” says Hurt, but “it’s not clear if it’s a good idea to use very large amounts of chemicals in a marine environment.”

But it’s not clear whether nanosorbents are a good idea, either. As Hurt designs the particles, Kane and her team set out to answer two questions. “First, will they work?” she asks. “And then, will they be toxic to the organisms?”

“They might be worse,” Hurt acknowledges. “We don’t know.”

Engineering Prevention

To begin to answer these questions, Kane has a small steel tank in her lab. Like a miniature wave pool, the open-air tank bubbles with seawater maintained at exactly 72 degrees. Soon this will be home to a small colony of brine shrimp, tiny marine organisms that, as larvae in the wild, are eaten by small fish, which, in turn, are used as bait to catch larger fish, which are eaten by people. As such, the brine shrimp are a good “indicator species” for study.

“We don’t want to have these kinds of dispersants accumulate up the food chain,” says Kane, peeking at the churning water.

A tube runs from a beaker into the basin, helping to aerate the water. As the shrimp grow in the lab, Kane and her colleagues will release oil and Hurt’s nanoparticles into the water with them to see what happens. Will they stop swimming? Will they die? Will their RNA reflect toxicity or injury? If so, Kane says, she is confident that her colleagues can alter the nanoparticles to reflect her findings.

“Engineers are very clever,” she says with a smile. “If we can identify the specific properties that are associated with the toxic effects, they can design [the nanoparticles] or process them to eliminate those properties or reduce those properties and reduce their toxicity.” And part of the excitement of studying nanoparticles is the ability to intervene now, in the very early stages—to prevent environmental and health disasters, rather than clean them up after the fact.

“When you think about what happened with the widespread use of asbestos throughout the 20th century— and we’re still suffering the consequences because of the long latent period of those diseases—the fact that those fibers persist in the buildings and in the environment and we’re still being exposed,” says Kane, “that’s a very expensive lesson. We do not want to repeat that tragedy again.”

by Beth Schwartzapfel ’01
Photographs by Karen Philippi
Courtesy of Brown Medicine Magazine

A SMART(er) way to track influenza

Brown University researchers have created a reliable and fast flu-detection test that can be carried in a first-aid kit. The novel prototype device isolates influenza RNA using a combination of magnetics and microfluidics, then amplifies and detects probes bound to the RNA. The technology could lead to real-time tracking of influenza. Results are published in the Journal of Molecular Diagnostics.

PROVIDENCE, R.I. [Brown University] — In April 2009, the world took notice as reports surfaced of a virus in Mexico that had mutated from pigs and was being passed from human to human. The H1N1 “swine flu,” as the virus was named, circulated worldwide, killing more than 18,000 people, according to the World Health Organization. The Centers for Disease Control and Prevention in the United States said it was the first global pandemic in more than four decades.

Swine flu will not be the last viral mutation to cause a worldwide stir. One way to contain the next outbreak is by administering tests at the infection’s source, pinpointing and tracking the pathogen’s spread in real time. But such efforts have been stymied by devices that are costly, unwieldy and unreliable. Now, biomedical engineers at Brown University and Memorial Hospital in Rhode Island have developed a biochip that can detect the presence of influenza by zeroing in on the specific RNA sequence and then using tiny magnets in a tube to separate the flu-ridden sequence from the rest of the RNA strand. The result: A reliable, fast prototype of a flu-detection test that potentially can be carried in a first-aid kit and used as easily as an iPhone.

“We wanted to make something simple,” said Anubhav Tripathi, associate professor of engineering at Brown and the corresponding author on the paper, published in the Journal of Molecular Diagnostics. “It’s a low-cost device for active, on-site detection, whether it’s influenza, HIV, or TB (tuberculosis).”

The Brown assay is called SMART, which stands for “A Simple Method for Amplifying RNA Targets.” Physically, it is essentially a series of tubes, with bulbs on the ends of each, etched like channels into the biochip.

There are other pathogen-diagnostic detectors, notably the Polymerase Chain Reaction device (which targets DNA) and the Nucleic Acid Sequence Based Amplification (which also targets RNA). The SMART detector is unique in that the engineers use a DNA probe with base letters that match the code in the targeted sequence. This ensures the probe will latch on only to the specific RNA strand being assayed. The team inundates the sample with probes, to ensure that all RNA molecules bind to a probe.

“The device allows us to design probes that are both sensitive and specific," Tripathi said.

Anubhav Tripathi
“We wanted to make something simple. (This is) a low-cost device
for active, on-site detection, whether it’s influenza, HIV, or TB.”
Credit: Mike Cohea/Brown University

This approach creates excess — that is, probes with no RNA partners. That’s OK, because the Brown-led team then attached the probes to 2.8 micron magnetic beads that carry the genetic sequence for the influenza RNA sequence. The engineers then use a magnet to slowly drag the RNA-probe pairs collected in the bulb through a tube that narrows to 50 microns and then deposit the probes at a bulb at the other end. This convergence of magnetism (the magnetized probes and the dragging magnets) and microfluidics (the probes’ movement through the narrowing channel and the bulbs) serves to separate the RNA-probe pairs from the surrounding biological debris, allowing clinicians to isolate the influenza strains readily and rapidly for analysis. The team reports that it tracks the RNA-probe beads flawlessly at speeds up to 0.75 millimeters per second.

“When we amplify the probes, we have disease detection,” Tripathi said. “If there is no influenza, there will be no probes (at the end bulb). This separation part is crucial.”

Once separated, or amplified, the RNA can be analyzed using conventional techniques, such as nucleic acid sequence-based amplification (NASBA).

The chips created in Tripathi’s lab are less than two inches across and can fit four tube-and-bulb channels. Tripathi said the chips could be commercially manufactured and made so more channels could be etched on each.

The team is working on separate technologies for biohazard detection.

Stephanie McCalla, who earned her doctorate at Brown last year and is now at the California Institute of Technology, is the first author on the paper. Brown professors of medicine Steven Opal and Andrew Artenstein, with Carmichael Ong and Aartik Sarma, who earned their undergraduate degrees at Brown, are contributing authors.

The U.S. National Institutes of Health and the National Science Foundation funded the research.

- by David Orenstein

How ion bombardment reshapes metal surfaces

Ion bombardment of metal surfaces is an important, but poorly understood, nanomanufacturing technique. New research using sophisticated supercomputer simulations has shown what goes on in trillionths of a second. The advance could lead to better ways to predict the phenomenon and more uses of the technique to make new nanoscale products.

PROVIDENCE, R.I. [Brown University] — To modify a metal surface at the scale of atoms and molecules — for instance to refine the wiring in computer chips or the reflective silver in optical components — manufacturers shower it with ions. While the process may seem high-tech and precise, the technique has been limited by the lack of understanding of the underlying physics. In a new study, Brown University engineers modeled noble gas ion bombardments with unprecedented richness, providing long-sought insights into how it works.

Three new mechanisms at the nanoscale
A computer-model image of an island of metal atoms
formed after bombardment by noble gas ions. Atoms
disturbed by the bombardment cluster together under
the surface and then glide back up in a matter of 2.1
trillionths of a second, or picoseconds (ps).
Credit: Kim Lab/Brown University

“Surface patterns and stresses caused by ion beam bombardments have been extensively studied experimentally but could not be predicted accurately so far,” said Kyung-Suk Kim, professor of engineering at Brown and co-author of the study published May 23 in the Proceedings of the Royal Society A. “The new discovery is expected to provide predictive design capability for controlling the surface patterns and stresses in nanotechnology products.”

The improved understanding could open the door to new technologies, Kim said, such as new approaches to make flexible electronics, biocompatible surfaces for medical devices, and more damage-tolerant and radiation-resistant surfaces. The research applies to so-called “FCC” metals such as copper, silver, gold, nickel, and aluminum. Those metals are crystals made up of cubic arrangements of atoms with one at each corner and one in each cube-face center.

Scientists have been trying to explain the complicated process for decades, and more recently they have begun to try modeling it on computers. Kim said the analysis of the Brown team, including lead author and postdoctoral scholar Sang-Pil Kim, was more sophisticated than previous attempts that focused on a single bombardment event and only isolated point defects within the metal substrate.

“In this work, for the first time, we investigate collective behavior of those defects during ion bombardments in terms of ion-substrate combinations,” Kyung-Suk Kim said.

The new model revealed how ion bombardments can set three main mechanisms into motion in a matter of trillionths of a second. The researchers dubbed the mechanisms “dual layer formation,” “subway-glide mode growth,” and “adatom island eruption.” They are a consequence of how the incoming ions melt the metal and then how it resolidifies with the ions occasionally trapped inside.

When ions hit the metal surface, they penetrate it, knocking away nearby atoms like billiard balls in a process that is akin, at the atomic level, to melting. But rather than merely rolling away, the atoms are more like magnetic billiard balls in that they come back together, or resolidify, albeit in a different order.

Some atoms have been shifted out of place. There are some vacancies in the crystal nearer to the surface, and the atoms there pull together across the empty space, that creates a layer with more tension. Beneath that is a layer with more atoms that have been knocked into it. That crowding of atoms creates compression. Hence there are now two layers with different levels of compression and tension.This “dual layer formation” is the precursor to the “subway-glide mode growth” and “adatom island eruption”.

A hallmark of materials that have been bombarded with ions is that they sometimes produce a pattern of material that seems to have popped up out of the original surface. Previously, Kyung-Suk Kim said, scientists thought displaced atoms would individually just bob back up to the surface like fish killed in an underwater explosion. But what the team’s models show is that these molecular islands are formed by whole clusters of displaced atoms that bond together and appear to glide back up to the surface.

“The process is analogous to people getting on a subway train at suburban stations, and they all come out together to the surface once the train arrives at a downtown station during the morning rush hour,” Kyung-Suk Kim said.

The mechanisms, while offering a new explanation for the effects of ion bombardment, are just the beginning of this research.

 “As a next step, I will develop prediction models for nanopattern evolution during ion bombardment which can guide the nanomanufacturing processes,” Sang-Pil Kim said. “This research will also be expanded to other applications such as soft- or hard-materials under extreme conditions.”

In addition to Kyung-Suk Kim and Sang-Pil Kim, other authors include Huck Beng Chew, Eric Chason and Vivek Shenoy.

The research was funded by the Korea Institute of Science and Technology, the U.S. National Science Foundation, and the U.S. Department of Energy. The work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number OCI-1053575.