Photo: Fleece Traveler

Guest Post by Elizabeth Dougherty from the Ask an Engineer series, published by MIT’s School of Engineering

Yes, but you can’t generate enough to power the roller coaster with itself…

“Imagine a straight-line, one-hill roller coaster. It’s boring to ride, but it’s a useful example,” says Aaron Johnson, a PhD student in aeronautics and astronautics. If you start your ride at ground level, the first challenge is getting the coaster to the top of the hill. This takes energy, so you expend what you need against gravity and friction to get the coaster to the top. When the coaster crests the hill, all of the energy you have just expended against gravity is now stored as potential energy—though exactly how much depends on the height of the hill and the weight of the cars and passengers.

In an ideal world, Johnson says, a perfectly efficient energy collector on a frictionless coaster in a vacuum should be able to harness that potential energy and convert it to enough kinetic energy on the way down to drive you up a hill of exactly the same height. But in the real world, energy collection is more complicated. Much of the potential energy you have just gathered is going to scatter. Friction generates heat energy in the track and wheels, and drag buffets the cars and passengers, heating them and the air around them and dissipating more of your energy. This dispersion means realizing all of your potential is nearly impossible.

Interestingly, not all of this energy needs to be completely lost—whether it’s from a roller coaster or any other moving vehicle. One way to collect some of the energy that dissipates from moving vehicles is through something called regenerative braking, as used in hybrid cars such as the Toyota Prius. Regenerative brakes use energy normally lost to heat and friction during braking to charge batteries that power the car. “It works, but you’re never going to get enough energy to bring you back up the hill again,” says Johnson. “You’ve lost some of it to heat, plus the regenerative braking process isn’t 100 percent efficient.” (In Pittsburgh, engineers recently created just such a demonstration coaster and used the collected energy to power a display of amusement park lights.)

Another approach is to add a turbine to the coaster to collect wind energy. Airplanes do this. In an emergency, such as a power failure, a plane drops a so-called ram air turbine from a hatch. The turbine collects wind energy to power hydraulics and critical instruments. “It’s very inefficient, so it’s usually only for emergency use,” says Johnson.

While no solution is perfect, regenerative brakes and turbines are constantly being reworked and redesigned to become more efficient. For instance, in turbines, the shape and twist of the blade matters. “There’s a lot of people trying to design the most efficient blade possible,” says Johnson.

Visit the MIT School of Engineering’s Ask an Engineer site for answers to more of your questions.


Guest Post by Peter Dunn from the Ask an Engineer series, published by MIT’s School of Engineering

In an era when everything else is accelerating, airplanes are actually flying at slower speeds than they used to…

A 1950s advertisement for the Boeing 707; Credit: 1950s unlimited

“Your link to faraway continents in hours less time: the new, fabulously swift Boeing 707.”
Credit: 1950s unlimited

Specified cruising speeds for commercial airliners today range between about 480 and 510 knots, compared to 525 knots for the Boeing 707, a mainstay of 1960s jet travel. Why? “The main issue is fuel economy,” says Aeronautics and Astronautics professor Mark Drela. “Going faster eats more fuel per passenger-mile. This is especially true with the newer ‘high-bypass’ jet engines with their large-diameter front fans.”

Observant fliers can easily spot these engines, with air intakes nearly 10 feet across, especially on newer long-range two-engine jetliners. Older engines had intakes that were less than half as wide and moved less air at higher speeds; high-bypass engines achieve the same thrust with more air at lower speed by routing most of the air (up to 93 percent in the newest designs) around the engine’s turbine instead of through it. “Their efficiency peaks are at lower speeds, which causes airplane builders to favor a somewhat slower aircraft,” says Drela. “A slower airplane can also have less wing sweep, which makes it smaller, lighter and hence less expensive.” The 707’s wing sweep was 35 degrees, while the current 777’s is 31.6 degrees.

There was, of course, one big exception: the Concorde flew primarily trans-Atlantic passenger routes at just over twice the speed of sound from 1976 until 2003. Product of a treaty between the British and French governments, the Concorde served a small high-end market and was severely constrained in where it could fly. An aircraft surpassing the speed of sound generates a shock wave that produces a loud booming sound as it passes overhead; fine, perhaps, over the Atlantic Ocean, but many countries banned supersonic flights over their land. The sonic-boom problem “was pretty much a show-stopper for supersonic transports,” says Drela.

Some hope for future supersonic travel remains, at least for those able to afford private aircraft. Several companies are currently developing supersonic business jets. Their smaller size and creative new “boom-shaping” designs could reduce or eliminate the noise, and Drela notes that supersonic flight’s higher fuel burn per passenger-mile will be less of an issue for private operators than airlines. “But whether they are politically feasible is another question,” he notes.

For now, it seems, travelers will have to appreciate the virtues of high-bypass engines, and perhaps bring along a good book.

Visit the MIT School of Engineering’s Ask an Engineer site for answers to more of your questions.


Once again, MIT has been ranked the best graduate engineering school by U.S. News & World Report, the position MIT has held since 1990 in the magazine’s annual ratings of graduate schools. Who’s next in line? Stanford, UC Berkeley, and Caltech.

How the world sees MIT.

MIT from above.

In the School of Engineering, top-ranked graduate engineering programs include aerospace engineering; chemical engineering; materials engineering; computer engineering; electrical engineering (tied); mechanical engineering (tied); and nuclear engineering (tied).

USNews and World Report does not rank all disciplines annually. In the first sciences evaluations in several years, the School of Science took the top spot in biological sciences (tied); chemistry (tied) plus an additional top ranking in the specialty of inorganic chemistry; computer science (tied); mathematics (tied) plus top ranking in discrete mathematics and combinations; and physics.

The MIT Sloan School of Management’s graduate programs in information systems, production/operations, and supply chain/logistics were again ranked first this year; Sloan was ranked the #5 business school.

Read the MIT News article to see which other MIT disciplines scored in the top five nationally and the contenders in the ties.


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Guest Blogger: Camilla Brinkman, Edgerton Center

MIT alumni of the 2004 Remote Operated Vehicle (ROV) team play a role in a new documentary film, Underwater Dreams, the story of four Mexican-American teenagers from an impoverished area of Arizona who challenged and beat the MIT team in a national contest, a feat that drew national media attention.

“Passionate engineering knows no boundaries, and to celebrate these students’ impressive feat was the right thing to do,” says Ed Moriarty '76, during the filming. He first invited the team to MIT in 2004.

“Passionate engineering knows no boundaries, and to celebrate these students’ impressive feat was the right thing to do,” says Ed Moriarty ’76. From left, Oscar Vazquez, Lauren Cooney ’06, SM ’09, and Moriarty during filming. Photo: Camilla Brinkman.

Recently the Edgerton Center invited the MIT and Arizona team members to campus to film commentary on the impact of the Marine Advanced Technology Education ROV Competition on both teams. The filming captured comments by Kurt Stiehl ’07, Lauren Cooney ’06, Jordan Stanway ’06, and Thaddeus Stefanov-Wagner ’06 as well as the Carl Hayden Community High School team and coach.

“I was thrilled because I knew how much the invitation [to MIT] would mean to the Carl Hayden students. In 2004, they had not really had the opportunity to interact with the MIT team. But more importantly, as Oscar Vazquez later said, the invitation was such a sign of respect for what these boys and this team from Phoenix had accomplished,” said Mary Mazzio of 50 Eggs Films, who wrote and directed the film.

The Carl Hayden team had been invited to MIT to celebrate the tournament but they could not travel by plane because they were undocumented.

During the filming, each team commiserated about their mishaps at the 2004 competition.

The Carl Hayden team’s soldered robot components melted in the hot Arizona sun en route to the competition. MIT’s robot suffered catastrophic damage in transit and had to be rebuilt. Then, the day before the competition, the Carl Hayden team discovered that the mechanical housing of their robot was leaking. One team member came up with an ingenious solution—tampons as a plug.

“What the Carl Hayden team did was totally impressive,” said Stiehl, now a product designer at Apple, who credits landing his job to the hands-on experience he gained on the ROV team. “The practicalities of shipping products versus building a robot are surprisingly similar and I use everything from basic system architecture development to project scheduling and team building.”

“It’s still affecting my life, even 10 years after,” said Oscar Vazquez, a Carl Hayden alumnus. “It gave me a career in engineering; it helped me pay for college; it brought me to MIT today; it sent me on the right path.”

And the story is still unfolding. Along with Underwater Dreams, another film about the Carl Hayden team, starring George Lopez and Marisa Tomei, is set to be released in the fall.

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Professor Linda Griffith leads MIT’s Center for Gynepathology Research, founded in 2009.

Professor Linda Griffith leads MIT’s Center for Gynepathology Research, founded in 2009.

Update: Watch the MIT’s Research in Women’s Health webcast.

In the March 2014 Faculty Forum Online, Linda G. Griffith, director of MIT’s Center for Gynepathology Research (CGR), shared new techniques for attacking endometriosis and research on systems biology and tissue engineering that has impact on clinical practice in gynecology. Follow the MIT Alumni Association on Twitter or use the hashtag #mitfaculty for live tweets during the event. Watch the archived webcast.

CGR brings together engineers, biologists, and clinicians to work on understanding of the basic biology, physiology, and pathophysiology of the female reproductive tract and the diagnosis and treatment of related diseases.

Griffin faced some of the tough issues CGR works on when she had her own breast cancer diagnosis. Read about her journey in the New York Times article, “Cancer Fight: Unclear Tests for New Drug.”




Research focused on some women’s health issues, such as breast cancer, receives significant attention in scientific and funding communities while other areas, such as gynecological disorders, garner much less interest and support.

These disparities led MIT Department of Biological Engineering Professor Linda Griffith to co-found the MIT Center for Gynepathology Research, an interdisciplinary research group that brings new engineering and science approaches into the underserved area of gynepathology.

In the March 2014 Faculty Forum Online, Griffith shared insights into new techniques for attacking endometriosis and discussed research on systems biology and tissue engineering that has impact on clinical practice in gynecology.

Following her comments, Griffith—a renowned expert on regenerative medicine—took live questions from the worldwide MIT community. Enjoy a sample or watch the full webcast then continue the discussion in the comments below.


Linda Griffith

About Linda Griffith

Professor of Biological and Mechanical Engineering Linda Griffith’s research focuses on tissue engineering, which the manipulation of cells using to form multi-dimensional structures that carry out the functions of normal tissue in vitro or in vivo. Her work focuses on controlling the spatial and temporal presentation of molecular ligands and physical cues which are known to influence cell behavior.

Griffith is a member of the National Academy of Engineering and the recipient of a MacArthur Foundation Fellowship, the Popular Science Brilliant 10 Award, NSF Presidential Young Investigator Award, and the MIT Class of 1960 Teaching Innovation Award. As chair of MIT’s Undergraduate Curriculum Committee for Biological Engineering, she led development of the Biological Engineering undergraduate degree program—MIT’s first new undergraduate major in more than 40 years.

She earned a bachelor’s degree from Georgia Tech and a doctorate from the University of California at Berkeley, both in chemical engineering.


MIT Department of Biological Engineering profile
MIT Center for Gynepathology Research

Cancer Fight: Unclear Tests for New Drug,” New York Times
MIT bioengineer works to unravel endometriosis,” Boston Globe
Scientist takes aim at her longtime silent scourge,” Boston Globe

About Faculty Forum Online

Eight times per season, the Faculty Forum Online presents compelling interviews with faculty on timely and relevant topics. Viewers watch and participate in live 30-minute interviews via interactive chat. Since its inception in 2011, archival editions of these programs have been viewed more than 50,000 times.

For the 2013-2014 season, the Alumni Association will produce three public service-themed evening editions, titled “One Community Together in Service.”


Downton Abbey fans have seen scant evidence of 20th-century media in the Masterpiece Classic program, but that may change in coming seasons. Thanks to the founding of BBC Radio in 1927, estates in financial trouble like that which Downton faces in season 4 get a huge boon, says Shundana Yusaf SM ’01.

In this edition of the MIT Alumni Books Podcast, Yusaf, a professor of architecture at the University of Utah, discusses her book Broadcasting Buildings: Architecture on the Wireless. Listen to this podcast9780262026741

Since architecture was a large focus of early BBC productions, the public came to appreciate homes like the Crawleys rather than looting or pillaging them as aristocratic strongholds in a changing world.

“Downton Abbey is a perfect example of houses becoming white elephants,” says Yusaf.

“They became a burden for the families…and architects become champions of conservation, but it puts them in a strange position. Conservation means that you have to promote the protection of properties that in popular culture are seen as symbols of historical injustice. Now you have to revamp them and package them as heritage of the people who have been subjugated.”


In the podcast, Yusaf discusses this topic and others, including the role of media in transforming architecture, how her MIT education made her rethink what one could do with an architecture degree, and how technology is changing the way people visit holy spaces around the world.

Hear more by listening to this podcast interview.

The MIT Alumni Books Podcast presents alumni authors discussing their latest books. It can be found on iTunes and on most other podcast platforms. Help us keep up with recent books or send along names of alumni authors you’d like to hear interviewed.

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Nate Silver and Daryl Morey, MBA ’00, at the MIT Sloan Sports Analytics Conference. (Image via MIT Sloan)

Nate Silver and Daryl Morey MBA ’00 at the MIT Sloan Sports Analytics Conference. (Image via MIT Sloan)

In February 2007, Daryl Morey MBA ’00 convened a small, one-day conference of about 175 MIT students, sports fans, and professionals. The sessions were held in MIT classrooms and focused on a niche topic—sports analytics, or the use of advanced statistics to employ data-driven strategy in athletics.

Nearly seven years later, thanks in part to the success of that conference, that topic has exploded in relevance, and the annual MIT Sloan Sports Analytics Conference (SSAC) has positioned MIT as a pivotal part of the burgeoning sports analytics industry.

“We held the first conference at MIT basically because I was an alum and they were supportive,” says Morey, the SSAC conference co-chair who, in 2004, helped Sloan initiate one of the first MBA programs with a sports analytics courses. “Today, analytics, sports, and MIT makes perfect sense.”

The two-day conference annually attracts a sold-out audience of nearly 3,000 attendees that includes more than 300 owners, players, and representatives from the highest-level professional teams in the U.S. and Europe.

Morey is perhaps the most well-known MIT alum working in professional sports—he is general manager and managing director of basketball operations for the NBA’s Houston Rockets—but he is not alone. Nearly every team in the U.S.’s top professional leagues has created analytic-specific positions to help determine in-game and business strategy, and MIT alumni are a small but growing group that is filling those roles.

Brian Bilello '97

Brian Bilello ’97

“More alumni are getting involved in sports because the analytical skillset is becoming more valuable and more appreciated,” says Brian Bilello ’97, president of soccer’s New England Revolution. “I studied chemical engineering but MIT didn’t necessarily train me to be a chemical engineer. They trained me to solve chemical engineering problems, and I can apply that perspective to my job with the Revolution.”

Sports teams now use analytics to provide a deeper level of analysis beyond traditional data. In baseball, front offices that once relied on well-known stats like home runs and runs batted in now place greater emphasis on advanced metrics like VORP (Value Over Replacement Player), a calculation created by Keith Woolner ’90 that demonstrates how much a player contributes to his team in comparison to a near-average replacement player at the same position.

After graduating from MIT, Woolner worked in software development and system management in Silicon Valley for more than a decade. As a hobby, he wrote stat-heavy articles for Baseball Prospectus (BP), an organization devoted to advanced statistics. In 2007, he parlayed his analysis to a position with the Cleveland Indians, where he works as director of baseball analytics and focuses on metrics for player valuation and game strategy.

“I always viewed my writing as being more of a scientist—I gathered information and presented it,” Woolner says. “In the early days at BP, we were very much the outsiders. By the time I joined Cleveland, I came into an organization that was data-driven and had buy-in towards analytics.”

The outdated idea of a team’s front office is one of retired coaches who have graduated to executive positions. In reality, most teams employ a group with varied expertise that includes scouts, former players, and stat-focused analysts and executives.


Farhan Zaidi ’98 (right)

“Front offices today are very balanced—traditional scouting backgrounds mixed with analytics backgrounds,” says Farhan Zaidi ’98, the Oakland Athletics’ director of baseball operations. “Much like MIT, sports now live in a very hypothesis-driven environment. You need to ask the right questions, accumulate the right data, and implement a strategy based on that data.”

While the number-crunching approach to improving on-field performance has gained significant attention—see Moneyball, the 2011 film starring Brad Pitt—teams are also taking an analytical approach unrelated to in-game strategy.

As vice president of business planning and basketball analytics for the NBA’s Phoenix Suns, Zaheer Benjamin MBA ’03 oversees an analytics team that focuses on diverse areas of Suns business, including marketing, ticket sales, and increasing revenue.

“Customer scoring models, for example, are something a lot of other industries do very well and sports is just getting up to speed on,” he says. “We use it to predict how likely season-ticket holders are to renew their ticket packages and align our resources to be as efficient as possible.”

While it continues to grow in popularity—Fast Company named the conference the third-most innovative sports organization in the world in 2012—it remains an MIT-rooted event. The conference’s organizing committee includes more than 60 MIT Sloan alumni and current students.

“That Venn diagram of MIT and sports may never have a ton of people in the middle,” Morey says. “But the MIT skillset fits perfectly with what teams are trying to accomplish. I’ve already hired one MIT alumni. I’d hire five more if I could.”

The 2014 conference takes place Feb. 28-March 1 in Boston and offers reduced-rate tickets for MIT alumni. Visit for more information.


How do we make sense of the tsunami of information that surrounds us when even professional news editors find it challenging?

61Fresh offers history in real time, updated every 10 minutes.

61Fresh offers Boston-area history in real time, updated every 10 minutes.

One answer could be 61Fresh, a crowd-driven news aggregator that searches tweets linking to 500 Boston-area websites every 10 minutes, identifies trending news bits, and then passes them on to Twitter followers or website readers.

61Fresh is among the many projects developed in a collaboration between GlobeLab, the Boston Globe’s R&D group, and the MIT Center for Civic Media (CFCM). Ali Hashmi, a civic media researcher and MIT Media Lab graduate student, contributed to 61Fresh as a Knight Fellow last summer by developing software that helped parse the universe of tweets. Among his projects was building natural language processing system that classified sports and non-sports news, so readers could modify their information streams.

For 61Fresh to work, you have to get rid of human decision makers, Hashmi says, they are just too slow. Algorithms churn through the tweets, identify what texts and URLs are retweeted, and determine—and share—the rising news.

“We can actually extract all these rising news items in real time and give you an accurate snapshot of how people are sharing news and what pieces of news are rising,” Hashmi says. And it’s more than just the news of the day, he says. “It is a very real time account of history in progress.”

PageOneX project

One collaboration, using printed newspapers and the online tool PageOneX, created a front-page visualization of guns, war, and terrorism. Courtesy CFCM.

Hashmi and CFCM are not just news hounds; they want to understand the impact of media tools and practices on communities worldwide. Hashmi, an expert in machine learning and natural language processing, is also studying the interactions between information published by the mainstream media in Pakistan and local bloggers.  Follow Hashmi on Twitter for more on his research.

Learn how the Nieman Journalism Lab described 61Fresh, which was funded by a grant from the Knight Foundation.

Ongoing collaborations bring authentic journalism challenges into the classroom and CFCM researchers are embedded at the GlobeLab, working on the technical issues facing newsrooms.

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Guest Blogger: Bill Doncaster, for MIT Sloan

The 2014 MIT Sloan Women in Management (SWIM) Conference added a new challenge this year, a chance for MIT women entrepreneurs to pitch their startups for a $1,000 prize. Held February 8 at the MIT Media Lab, this is the first time such a competition was held for women entrepreneurs at MIT.

Systems president Natalya Brikner presents her satellite propulsion technology.

Systems president Natalya Brikner presents her satellite propulsion technology.

Ten startups, selected from 30 applications MIT-wide, presented new ideas ranging from app-based parenting resources for educational activities to a new device to monitor and prevent leg injuries for prize show horses. In the end, the high-caliber presentations led to a quandary for the panel of three judges—who chose two winners rather than one for the $1,000 prize.

One winner was Accion Systems, presented by CEO and president Natalya Brikner. Accion, which is developing propulsion systems for small satellites, is queued up for its first space test in April. Most of the 300 or so satellites launched each year remain only in orbit for days because there is no propulsion system to keep smaller satellites in orbit. According to Brikner, a PhD student in the Department of Aeronautics and Astronautics, Accion’s cost-effective systems would increase the life and operability of small satellites.

“The engines that are flying on satellites today were designed before the first handheld calculator was invented,” Brikner said. “We want to change that. Our systems are lighter, smaller, and more efficient than existing systems and our product line is infinite—customers can put thrusters anywhere they want on a satellite.”

Caroline Mauldin, a first year student in MIT Sloan’s dual degree program with Harvard’s John F. Kennedy School of Government, stayed closer to the earth with her company, Love Grain, the second winner. Love Grain serves the growing gluten-free food market through products made with teff, a gluten-free grain from Ethiopia. The company is already selling its first product, a pancake and waffle mix, and is developing an energy bar.

“Here in the United States, there are 42 million gluten-free consumers who lack nutritious and delicious options, and I know that because I’m one of them,” said Mauldin. “We’re expected to spend $6 billion on gluten free products by 2015. Teff is a tiny part of the market right now. We are creating a sustainable, compassionate business model that connects Ethiopian farmers to the United States.”

Learn more about the pitch contest and the conference.