Exploring ancient engineering to inform the future

Three-dimensional laser scanners and unpiloted aerial vehicles in hand, a group of MIT students walked through the Privernum archaeological site capturing information about degrading structures and newly-exposed mosaics in an effort to build digital models of how the site was constructed in its prime and design appropriate conservation strategies.

The exercise was one of many research opportunities afforded to students during the second annual program in Materials in Art, Archaeology and Architecture (ONE-MA³) between June 16 and July 5.

Hosted by the MIT Department of Civil and Environmental Engineering (CEE), ONE-MA³ exposes students to the remarkable methods and history of ancient engineers in Italy, while challenging them to consider how ancient successes could be used as building blocks for the development of new and innovative techniques, architectural structures, materials, and designs.  

“In CEE, we engineer and create innovations to solve challenges identified from the world around us. We encourage our students to supplement their studies with fieldwork experiences like ONE-MA³,” says Markus Buehler, head of CEE and the McAfee Professor of Engineering. “By analyzing and evaluating our environment and the structures and materials that make up our world, such as those in Italy, we are able to identify opportunities for cutting-edge solutions for the future.”

During ONE-MA³, students explored Privernum, Rome, Pompeii, Turin, and Aramengo, stopping at archaeological sites, hearing from experts about their vocations and getting hands-on fieldwork experience. Led by Admir Masic, the Esther and Harold E. Edgerton Career Development Professor of CEE and founder of the program, and teaching assistants Linda Seymour and Chad Loh, the group approached cultural heritage from multiple perspectives, using ancient societies as examples of excellence in engineering that withstand the tests of time.

“ONE-MA³ transforms historical destinations into opportunities for learning and discovery. Knowing how to apply advanced technologies directly in the field allows us to learn more about ancient objects and structures, while injecting new meaning to these places,” Masic says. “Students are able to touch 2,000-years-old structures, study their design, and recreate their very resilient materials using original raw materials. I think it is crucial for students to immerse themselves in past cultures and see the impact their work can have on our world.”

Using the past as inspiration for the future

Critical to students’ understanding of the history, materials, and methods of ancient times is the ability to get direct hands-on experience working with archaeologists and curators to understand and learn about artifacts and both traditional and cutting-edge tools and techniques. To do this, students on ONE-MA³ were granted special access to restricted laboratories and areas of the ancient sites and museums that were not open to the public, including Pompeii and the Vatican.

In Privernum, the archaeological site located in what is now Priverno, the students used their unpiloted aerial vehicle, 3-D scanners, and thermal cameras to capture three-dimensional imagery to ultimately create a reconstruction of the site, useful for the study the interaction of this ancient infrastructure with the environment. While working in Privernum, the ONE-MA³ team also exposed and analyzed dirt-covered mosaics, taking photogrammetry of the patterns and artwork to later stitch the images together to visualize how they appeared inside dwellings during ancient times.

“My favorite part of the fieldwork was uncovering and analyzing the mosaics in Privernum,” said Sierra Rosenzweig, a rising sophomore majoring in CEE. “They were really beautiful and it felt like we were discovering clues to the past, even though some of them had been uncovered in the past and had been reburied at one point from wind.”

Students were also given the opportunity to create their own Roman mosaics and fresco paintings based on ancient methods and recipes learned and witnessed during ONE-MA³. Rosenzweig, for example, uncovered a mosaic with a unique wave design in Privernum, and was able to later recreate the design on a new mosaic using the same materials and methods as the ancient times.  

Also in Privernum, the group learned from local experts how ancient Roman mortar was concocted and was given the opportunity to make some of their own. The experiment opened doors for students to consider how the ancient recipe could be a starting point for more durable and sustainable cement pastes for modern construction. For instance, the students were challenged to improve the mortar’s strength and the time it takes to set.

ONE-MA³ also took a few days to be tourists and explore Rome. While visiting the Vatican, the group was given exclusive access to the restricted restoration laboratories of the Vatican Museum. The labs conduct research and restoration, and gave students a firsthand look into the Vatican’s conservation efforts.

“We were given such an intimate view of the conservation that goes on in the Vatican. We were able to ask the professional restorers, conservators, and scientists whatever we wanted about everything they were showing us,” says Zoe Lallas, a rising sophomore in CEE. “We got to see artifacts in the middle of the restoration process, we got to look at artifacts that restorers had worked tirelessly for months conserving. Hearing them talk about their work was amazing. They were all so passionate about the individual pieces and their pride was palpable in their explanations.”

The group next traveled to Pompeii, where they learned about ongoing research projects at the archaeological site and were given private access to the Laboratory of Applied Research in Pompeii. In the lab and restricted areas of Pompeii, students learned about the methods for uncovering clues to the past, and how, for example, the research team uses satellite data to evaluate the movement of structures at the site over time. CEE Professor John Williams also joined ONE-MA³ in Pompeii, and spoke to the group about virtual reality and how cultural heritage could use technologies such as HoloLens to create compelling experiences.

While in Turin, the group toured royal residences and were given lectures on the architecture to put the tours into context. At the Castello di Valentino, historians from Polytechnic of Turin spoke to the group on the Baroque architecture, whereas at the Venaria Reale students learned about scientific monitoring of restoration projects. The students next visited the Palazzina di Caccia di Stupinigi, where they were granted special access to the castle, which allowed exploration of the different construction techniques and to see the roof structures.

“The group was in awe as we walked into the central room of the Palazzina where we saw the extravagant central chandelier and paintings on the ceiling. The conservation of the Palazzina was a remarkable feat that the whole group genuinely admired,” Rosenzweig recalled in a CEE blog on ONE-MA³.

The experience was not limited to Italian heritage, however. Also in Turin, the students visited the Egyptian Museum, where they heard from the museum’s director about their conservation and restoration methods. The group then toured the museum, which included admiring art, Egyptian sculptures, and mummies. The Egyptian culture allowed the students to compare ancient Egyptian techniques with those seen in Italian art and structures. 

In Aramengo, a family that restores artwork greeted the group and led a discussion about their occupation and the different techniques they use when restoring art. The group was challenged with comparing these traditional methods with emerging methods learned elsewhere.

“The science of conserving art is particularly important because it gives us insight into historical context and culture. Everything from the colors they used and how they made them, to the materials the art was created on and how it interacts with and responds to the environment over time, can provide clues to their world and inspire future designs,” Masic says.

While the wide range of hands-on experiences, expert lectures and exclusive access tours and laboratory demonstrations provided insight and information, it was also a catalyst for a number of topics that students will pursue on campus in the upcoming fall semester. The annual occurrence of ONE-MA³ also opens the doors for future long-term collaborations and projects.

Bringing ancient Italy back to campus

ONE-MA³ is an exciting and travel-intensive few weeks, filled with a wealth of technical and cultural information. But the learning doesn’t stop in Italy: ONE-MA³ is a prerequisite for 1.057 (Heritage Science and Technology), where students will continue their research projects motivated by their Italian adventure.

“It injects new meaning to the class when we have a shared experience to reflect on,” Masic says. “We have found that students are more invested in the learning when they have been exposed to the topics in the real world and see the potential impact of their work.”

During the term, students will explore at greater depth the theory and practice behind cultural heritage, and relate what they experienced in Italy to their coursework and projects. Having been exposed to the concerns of cultural heritage practitioners on ONE-MA³, the students are tasked with formulating and designing projects that blend aspects of cultural heritage learned in Italy with current state-of-the-art science and engineering tools and methods.

“I think the combination of hands-on experiences and lectures during ONE-MA³ really helped the group think critically about ancient technologies and challenges conservationists face and how they could formulate projects to explore those areas,” Seymour says. “The project ideas for the fall that students suggested were incredibly diverse including conservation ethics, material design for modern structural applications and using virtual reality to bring our experience to people across the globe.”

The myriad of research topics afforded by ONE-MA³ exemplifies the interdisciplinary and wide-ranging nature of the experience. Each student brought his or her own unique interests to ONE-MA³, greatly diversifying the scope of the upcoming class projects.

“At the end of the trip we had a quick discussion about our coming projects in the fall. The variance of topics that arose is kind of crazy seeing as we were all on the same trip and learned the same things,” Lallas says. “But it seems like it should make for a very exciting semester.”

de MIT News http://ift.tt/2vmvs3Q

Closing the gender gap in mechanical engineering

In 2015, comments from a Nobel Prize-winning biochemist claiming female scientists distract their male colleagues in the lab immediately led to backlash across social media. Women shared selfies going about their routine conducting research to demonstrate just how “distracting” they are. Months later, individuals around the world responded to offhand comments about a female engineer with the hashtag #ILookLikeAnEngineer. Earlier this year, General Electric envisioned a reality in which female scientists, such as the late MIT Professor Emerita Millie Dresselhaus, are revered just as much as celebrities and athletes. 

These events reflect a wider movement to combat sexism and encourage women to pursue careers in science, technology, engineering, and math (STEM). The gender gap in these fields is pronounced, to be sure. In mechanical engineering, for example, only 13.2 percent of bachelor’s degrees in 2015 were earned by women, according to the American Society for Engineering Education (ASEE). However, this number is in stark contrast to the undergraduate population in MIT’s Department of Mechanical Engineering (MechE), which as of fall 2016, comprised 49.5 percent women.

So how did MechE achieve a gender split that far surpasses the national average? It’s a question that a team of researchers, including Kath Xu ’16, senior lecturer in mechanical engineering Dawn Wendell ’04 SM ’06 PhD ’11, and lecturer in comparative media studies and writing Andrea Walsh sought to answer. They presented their results in June at the 2017 American Society for Engineering Education Annual Conference.

Gender parity as a recruitment tool

The team found that gender parity starts before students set foot onto MIT’s campus. MIT’s Office of Admissions has employed a variety of tactics to recruit female applicants. “We have to fight against conventional wisdom,” says Dean of Admissions Stuart (Stu) Schmill in an interview with the researchers. Schmill and the rest of MIT Admissions have to combat the popular assumption that the Institute is predominately male. In actuality, MIT’s undergraduate population is 46.1 percent female.

Admissions utilizes various channels — including blogs and Campus Preview Weekend — to dispel the myth that women are not represented on campus. “What made MIT stand out to me as an applicant were the student blogs,” recalls Xu, who graduated with a degree in mechanical engineering. “They do a good job of showcasing the number of women and minorities at the school.”

Programs like the Women’s Technology Program (WTP), run through MechE and MIT’s Department of Electrical Engineering and Computer Science, also encourage young women to pursue STEM studies. The WTP invites female high school students to live on campus over the summer and gain hands-on engineering experience in labs and classes.

Highlighting the ratio of women in the student population is a “chicken-and-egg cycle,” as Schmill puts it in the study. MIT is able to attract female applicants by showcasing the number of women on campus, which then begets even more women on campus. Once these women are at MIT, they often gravitate toward female faculty for guidance and mentorship.

An existence proof

Seeing the effect female faculty members have on the women they teach helped former head of MechE Rohan Abeyaratne, who was also interviewed for the study, realize just how important it is to have women in leadership positions. One such faculty member is Anette (Peko) Hosoi, the Neil and Jane Pappalardo Professor of Mechanical Engineering and the first woman to be named associate department head in MechE.

“One thing I remembered greatly soon after Peko was hired was the number of female students who were going to her office hours was striking,” recalls Abeyaratne. The comfort level female students have with female faculty demonstrates the necessity for having more women in teaching roles.

In the study, the researchers found what female undergraduates are most interested in is assurance that they will have job prospects in the future. “When we talk to undergrads, they are not looking necessarily for role models,” explains Hosoi in the study. “They are looking for an existence proof. They want to know, ‘If I go down this path, is there going to be a job for me?’”

As students, both Xu and Wendell were able to find such existence proof on day one of majoring in mechanical engineering. Xu’s very first class was taught by Principal Research Scientist Simona Socrate SM ’90 PhD ’95. Meanwhile, Wendell’s first class was taught by Professor Emerita Mary Boyce SM ’84 PhD ‘87, who became MechE’s first female department head in 2008.

“At the end of the semester, I emailed Professor Boyce to ask her about being a mechanical engineer,” recalls Wendell, who now is a senior lecturer in the department. “She met with me for over an hour, telling me about her career and her passion for engineering.”

Cold calling female faculty

In their conversations with former and current faculty, the researchers found that 20 years ago, MechE wasn’t as welcoming of an environment for women. With just one female faculty member in the late 1990s, it was clear something had to change. The 2002 Report of the School of Engineering was a turning point and prompted Thomas Magnanti, then dean of engineering, to take action by requiring departments to enforce affirmative action. As part of MechE’s efforts, qualified women received phone calls encouraging them to apply to faculty positions.

One such woman was Hosoi. “When I arrived at MIT, there were a lot of women who had been hired at the same time,” she recalls in her interview with researchers. “At a junior women’s faculty lunch, somebody asked, ‘How did you end up at MIT?’ All of the answers were the same. ‘Somebody called and asked me to apply.’”

In addition to cold calling, the study found that altering faculty job descriptions to be more broad helped cast a wider net in department leadership’s efforts to ensure that more women had the opportunity to join the faulty.

Increasing awareness to reduce the gap

The first step toward closing the gender gap in STEM, according to Xu, Wendell, and Walsh’s findings, is acknowledging the gap exists. Increased awareness at MIT led to a concerted effort by departmental and Institute leadership to attract more female students and faculty members. "Achieving gender equity takes proactive effort and conscious strategies to achieve that goal," explains Walsh.

In addition to MechE’s commitment to achieving gender parity over the past two decades, there has been a great deal of support at an Institute level. MIT introduced more women’s programming across departments, invited speakers to discuss issues like imposter syndrome, and ensured women on campus had the support they need.  Additionally, MIT’s Program in Women’s and Gender Studies addresses issues of gender equity in STEM through courses and programming.

While these efforts have helped attract more women in the faculty and student populations, there is still more work to be done beyond the halls of MIT. “We aren’t just looking to make MIT a more welcoming place for women engineers, we also want to change the world,” adds Wendell. “Subtle bias is everywhere. I’m often mistaken for an administrative assistant, and when I give talks elsewhere, people will walk right past me and ask where the invited speaker is.”

The researchers conclude that the cultural shift needed to achieve gender parity in MechE was sparked by many small changes and the support of key allies on campus. It’s their hope that MIT and MechE’s example could help other schools. “We wanted to provide a blueprint that is broadly applicable to other universities that want to increase the female population in their STEM departments,” says Xu. More gender parity within universities, coupled with movements such as highlighting #WomeninSTEM on social media, could provide the catalyst needed to increase the number of women who pursue careers in STEM fields. 

de MIT News http://ift.tt/2udm4dL

Underground magma pulse triggered end-Permian extinction

Geologists from the U.S. Geological Survey and MIT have homed in on the precise event that set off the end-Permian extinction, Earth’s most devastating mass extinction, which killed off 90 percent of marine organisms and 75 percent of life on land approximately 252 million years ago.

In a paper published today in Nature Communications, the team reports that about 251.9 million years ago, a huge pulse of magma rose up through the Earth, in a region that today is known as the Siberian Traps. Some of this molten liquid stopped short of erupting onto the surface and instead spread out beneath the Earth’s shallow crust, creating a vast network of rock stretching across almost 1 million square miles.

As the subsurface magma crystallized into geologic formations called sills, it heated the surrounding carbon-rich sediments and rapidly released into the atmosphere a tremendous volume of carbon dioxide, methane, and other greenhouse gases.

“This first pulse of sills generated a huge volume of greenhouse gases, and things got really bad, really fast,” says first author and former MIT graduate student Seth Burgess. “Gases warmed the climate, acidified the ocean, and made it very difficult for things on land and in the ocean to survive. And we think the smoking gun is the first pulse of Siberian Traps sills.”

Getting to extinction’s roots

Since the 1980s, scientists have suspected that the Earth’s most severe extinction events, the end-Permian included, were triggered by large igneous provinces such as the Siberian Traps — expansive accumulations of igneous rock, formed from protracted eruptions of lava over land and intrusions of magma beneath the surface. But Burgess was struck by a certain incongruity in such hypotheses.

“One thing really stuck out as a sore thumb to me: The total duration of magmatism in most cases is about 1 million years, but extinctions happen really quickly, in about 10,000 years. That told me that it’s not the entire large igneous province driving extinction,” says Burgess, who is now a research scientist for the U.S. Geological Survey.

He surmised that the root cause of mass extinctions might be a shorter, more specific interval of magmatism within the much longer period over which large igneous provinces form.  

Digging through the data

Burgess decided to re-examine geochronologic measurements he made as a graduate student in the lab of Samuel Bowring, the Robert R. Shrock Professor of Geology in MIT’s Department of Earth, Atmospheric and Planetary Sciences.

In 2014 and 2015, he and Bowring used high-precision dating techniques to determine the timing of the end-Permian mass extinction and ages of ancient magmatic rocks that the team collected over three field expeditions to the Siberian Traps.

From the rocks’ ages, they estimated this magmatic period started around 300,000 years before the onset of the end-Permian extinction and petered out 500,000 years after the extinction ended. From these dates, the team concluded that magmatism in the Siberian Traps must have had a role in triggering the mass extinction.

But a puzzle remained. Even while lava erupted in massive volumes hundreds of thousands of years prior to the extinction, there has been no evidence in the global fossil record to suggest any biotic stress or significant change in the climate system during that period.

“You’d expect if these lavas are driving extinction, you’d see global evidence of biosphere decline,” Burgess says.

When he looked back through the group’s data, he noticed that rocks dated within the 300,000-year window prior to the start of the extinction were almost exclusively volcanic, meaning they formed from lava that erupted onto land. In contrast, the subsurface sills only started to appear just before the start of the extinction, 251.9 million years ago.

“I realized the oldest sills out there correspond, bang-on, with the start of the mass extinction,” Burgess says. “You don’t have any negative effects occurring in the biosphere when you’ve got all this lava erupting, but the second you start intruding sills, the mass extinction starts.”

Revised timeline

Based on his new observations of the data, Burgess has outlined a refined, three-stage timeline of the processes that likely triggered the end-Permian extinction. The first stage marks the start of widespread eruptions of lava over land, 252.2 million years ago. As the lava spews out and solidifies over a period of 300,000 years, it builds up a dense, rocky cap.

The second stage starts at around 251.9 million years ago, when the lava cap becomes a structural barrier to subsequent lava eruption. Instead, acending magma stalls and spreads beneath the lava cap as sills, heating up carbon-rich sediments in the Earth and releasing huge amounts of greenhouse gases to the atmosphere — almost precisely when the mass extinction event began. “These first sills are the key,” Burgess says.

The last stage begins around 251.5 million years ago, as the release of gases slows, even as magma continues to intrude into the sediments.

“At this point, the magma has already degassed the basin of most of its volatiles, and it becomes more difficult to generate large volumes of volatiles from a basin that’s already been cooked,” Burgess explains.

A culprit for other extinctions?

Could similarly short pulses of sills have triggered other mass extinctions in Earth’s history? Burgess looked at the geochronologic data for three other extinction events which scientists have found to coincide with large igneous provinces: the Cretaceous-Plaeogene, the Triassic/Jurassic, and the early Jurassic extinctions.

For both the Triassic/Jurassic, and the early Jurassic extinction events, he found that the associated large igneous provinces contained significant networks of sills, or intrusive magma, emplaced into sedimentary basins that likely hosted volatile gases. In these two cases, the extinction trigger might have been an initial short pulse of intrusive magma, similar to the end-Permian.

However, for the Cretaceous-Paleogene event — the extinction that killed off the dinosaurs — Burgess noted that the large igneous province that was erupting at the time is primarily composed of lavas, not sills, and was erupted into granitic rock, not a gas-rich sedimentary basin. Thus, it likely did not release enough greenhouse gases to exclusively cause the dinosaur die-off. Instead, Burgess says a combination of lava eruptions and the Chicxulub asteroid impact was likely responsible.

“Large igneous provinces have always been blamed for mass extinctions, but no one has really figured out if they’re really guilty, and if so, how it was done,” Burgess says. “Our new work takes that next step and identifies which part of the large igneous province is guilty, and how it committed the crime.”

The paper’s co-authors are Bowring and J.D. Muirhead, of Syracuse University. The research was supported, in part, by a U.S. Geological Survey Mendenhall Postdoctoral Research Fellowship, which was awarded to Burgess.

de MIT News http://ift.tt/2tQr6gP

Intermittent attention, poor memory shape public perceptions of inflation

Do you know your country’s current inflation rate? What do you think it will be in the future? And how do you, personally, try to plan your finances accordingly?

Those are important questions for economists and policymakers, because central bankers generally assess future expectations of inflation when setting interest rates. Yet as a new study co-authored by an MIT economist reveals, people have a haphazard approach to assessing inflation. Most citizens only pay attention to the topic intermittently, and they overestimate how bad inflation will become.

Still, there is some good news in these findings, based on research in the U.S. and Argentina, countries that have very different experiences with inflation. Many people are “rationally inattentive” to inflation, as economists put it. That means an occasional focus on the subject may actually help people avoid overreactions to price blips.

“There’s evidence of rational inattention,” says Alberto Cavallo, the Douglas Drane Associate Professor in Information Technology and Management at the MIT Sloan School of Management, and a co-author of the study. “People are paying attention when they need to.”

And now for the bad news.

“People have terrible memories,” Cavallo says. “Even in a place like Argentina, which has so much inflation, where this is so important to correctly estimate, people have no clue what past prices were. They tended to think past prices were much lower than they were, so they thought inflation was much higher than it is.” Overall, Cavallo adds, “There is often an upward bias in inflation expectations.”

The paper, “Inflation Expectations, Learning, and Supermarket Prices,” appears in the newest issue of the American Economic Journal: Macroeconomics. In addition to Cavallo, the authors are Guillermo Cruces of the National University of La Plata, in Argentina, and Ricardo Perez-Truglia of the University of California at Los Angeles.

Statistics vs. store prices

The study derives its findings from a series of online and offline surveys in both the U.S. and Argentina — in some cases conducted right after people have gone shopping in supermarkets.

The two countries were chosen as sites for the study precisely because of their contrasting inflation histories. The U.S. inflation rate was 1.8 percent over the five years before the study, while in Argentina the inflation rate was 22.5 percent. That helped the scholars to examine what effect the experience of high or low inflation may have.

The study produced multiple results. The researchers found that people in Argentina do tend to have absorbed more information about inflation than people in the U.S. — and as a consequence, they have more firmly entrenched ideas about the subject. For instance, respondents in the survey placed quite different amounts of emphasis on how much that new information would affect their views.

In the U.S., people assigned a weight of just 15 percent to prior beliefs when it came to making assessments about future inflation; in Argentina, people assigned a weight of about 50 percent to their prior beliefs.

“I think there’s good evidence in the paper that countries with higher inflation rates historically have people paying more attention, and thus stronger priors,” Cavallo says.

That also fits with the notion on “rational inattention,” since in the U.S., where inflation rates are lower and more stable, people can afford to have accumulated less information about the subject in the past.

“In the U.S., if inflation is 2 or 3 percent, it won’t change dramatically, and you are not affected too much,” Cavallo explains. “In Argentina, knowing what the inflation rate will be in the future is key for your salary. If it’s going to be 30 percent or 15 percent, that question becomes much more important.”

It is also the case that people pay more attention to select prices they personally encounter, not to aggregate inflation statistics, even if the larger data sets may be a better guide to overall prices. Based on a series of questions to consumers, the researchers found that people are willing to give specific supermarket prices more weight in their inflation expectations, compared to the aggregate (but more abstract) data.

“Within each country, we found people react more to the information of individual products,” Cavallo notes.

Additionally, the study found, in the U.S., 29 percent of the variation in inflation expectations is due to perceptions of past inflation, whereas in Argentina, 60 percent of the variation in expectations stems from perceptions. Meaning: People’s memories of past inflation vary widely.

As Cavallo observes, this could be a defense mechanism deployed by some people, since expectations tend to overshoot actual inflation increases.

“In a country like Argentina with high inflation, it’s better to have an upward bias,” he says. “It’s a protective mechanism to think things are going to be worse than they actually are.”

Great expectations

The current paper is related to an extended series of studies Cavallo and his colleagues have undertaken on inflation. Cavallo and MIT Sloan economist Roberto Rigobon are co-founders of the MIT-based Billion Prices Project, an innovative program launched several years ago that tracks prices in real time, partly as a way of evaluating the accuracy of official inflation statistics.

The current papers bears on the practices of monetary policy — the interest rates set by central banks. The so-called “real” interest rate consumers grapple with is a combination of the listed interest rates of lenders as well as inflation expectations.

If people expect inflation to be higher than interest rates, they will — in theory, at least — be more likely to buy products now, averting future inflation, rather than depositing money at low rates. In turn, that behavior could have significant macroeconomic effects.

Cavallo thinks the current study can help clarify for policymakers how people sort through information and shape their expectations in the first place.

“One policy implication is that governments can provide [people] either better aggregate statistics or better individual examples,” Cavallo says. “I think they should … make sure they communicate clearly to consumers [and] speak about goods that are important. We’re basically seeing how much people learn from the information we give them.”

de MIT News http://ift.tt/2ub7T8X

Transparent, flexible solar cells

Imagine a future in which solar cells are all around us — on windows and walls, cell phones, laptops, and more. A new flexible, transparent solar cell developed at MIT is bringing that future one step closer.

The device combines low-cost organic (carbon-containing) materials with electrodes of graphene, a flexible, transparent material made from inexpensive and abundant carbon sources. This advance in solar technology was enabled by a novel method of depositing a one-atom-thick layer of graphene onto the solar cell — without damaging nearby sensitive organic materials. Until now, developers of transparent solar cells have typically relied on expensive, brittle electrodes that tend to crack when the device is flexed. The ability to use graphene instead is making possible truly flexible, low-cost, transparent solar cells that can turn virtually any surface into a source of electric power.

Photovoltaic solar cells made of organic compounds would offer a variety of advantages over today’s inorganic silicon solar cells. They would be cheaper and easier to manufacture. They would be lightweight and flexible rather than heavy, rigid, and fragile, and so would be easier to transport, including to remote regions with no central power grid. And they could be transparent. Many organic materials absorb the ultraviolet and infrared components of sunlight but transmit the visible part that our eyes can detect. Organic solar cells could therefore be mounted on surfaces all around us and harvest energy without our noticing them.

Researchers have made significant advances over the past decade toward developing transparent organic solar cells. But they’ve encountered one persistent stumbling block: finding suitable materials for the electrodes that carry current out of the cell.

“It’s rare to find materials in nature that are both electrically conductive and optically transparent,” says Professor Jing Kong of the Department of Electrical Engineering and Computer Science (EECS).

The most widely used current option is indium tin oxide (ITO). ITO is conductive and transparent, but it’s also stiff and brittle, so when the organic solar cell bends, the ITO electrode tends to crack and lift off. In addition, indium is expensive and relatively rare.

A promising alternative to ITO is graphene, a form of carbon that occurs in one-atom-thick sheets and has remarkable characteristics. It’s highly conductive, flexible, robust, and transparent; and it’s made from inexpensive and ubiquitous carbon. In addition, a graphene electrode can be just 1 nanometer thick — a fraction as thick as an ITO electrode and a far better match for the thin organic solar cell itself.

Graphene challenges

Two key problems have slowed the wholesale adoption of graphene electrodes. The first problem is depositing the graphene electrodes onto the solar cell. Most solar cells are built on substrates such as glass or plastic. The bottom graphene electrode is deposited directly on that substrate — a task that can be achieved by processes involving water, solvents, and heat. The other layers are then added, ending with the top graphene electrode. But putting that top electrode onto the surface of the so-called hole transport layer (HTL) is tricky.

“The HTL dissolves in water, and the organic materials just below it are sensitive to pretty much anything, including water, solvents, and heat,” says EECS graduate student Yi Song, a 2016-2017 Eni-MIT Energy Fellow and a member of Kong's Nanomaterials and Electronics Group. As a result, researchers have typically persisted in using an ITO electrode on the top.

The second problem with using graphene is that the two electrodes need to play different roles. The ease with which a given material lets go of electrons is a set property called its work function. But in the solar cell, just one of the electrodes should let electrons flow out easily. As a result, having both electrodes made out of graphene would require changing the work function of one of them so the electrons would know which way to go — and changing the work function of any material is not straightforward.

A smooth graphene transfer

For the past three years, Kong and Song have been working to solve these problems. They first developed and optimized a process for laying down the bottom electrode on their substrate.

In that process, they grow a sheet of graphene on copper foil. They then transfer it onto the substrate using a technique demonstrated by Kong and her colleagues in 2008. They deposit a layer of polymer on top of the graphene sheet to support it and then use an acidic solution to etch the copper foil off the back, ending up with a graphene-polymer stack that they transfer to water for rinsing. They then simply scoop up the floating graphene-polymer stack with the substrate and remove the polymer layer using heat or an acetone rinse. The result: a graphene electrode resting on the substrate.

But scooping the top electrode out of water isn’t feasible. So they instead turn the floating graphene-polymer stack into a kind of stamp, by pressing a half-millimeter-thick frame of silicon rubber onto it. Grasping the frame with tweezers, they lift the stack out, dry it off, and set it down on top of the HTL. Then, with minimal warming, they can peel off the silicon rubber stamp and the polymer support layer, leaving the graphene deposited on the HTL.

Initially, the electrodes that Song and Kong fabricated using this process didn’t perform well. Tests showed that the graphene layer didn’t adhere tightly to the HTL, so current couldn’t flow out efficiently. The obvious solutions to this problem wouldn’t work. Heating the structure enough to make the graphene adhere would damage the sensitive organics. And putting some kind of glue on the bottom of the graphene before laying it down on the HTL would stick the two layers together, but would end up as an added layer between them, decreasing rather than increasing the interfacial contact.

Song decided that adding glue to the stamp might be the way to go — but not as a layer under the graphene.

“We thought, what happens if we spray this very soft, sticky polymer on top of the graphene?” he says. “It would not be in direct contact with the hole transport layer, but because graphene is so thin, perhaps its adhesive properties might remain intact through the graphene.”

To test the idea, the researchers incorporated a layer of ethylene-vinyl acetate, or EVA, into their stamp, right on top of the graphene. The EVA layer is very flexible and thin — sort of like food wrap — and can easily rip apart. But they found that the polymer layer that comes next holds it together, and the arrangement worked just as Song had hoped: The EVA film adheres tightly to the HTL, conforming to any microscopic rough features on the surface and forcing the fine layer of graphene beneath it to do the same.

The process not only improved performance but also brought an unexpected side benefit. The researchers thought their next task would be to find a way to change the work function of the top graphene electrode so it would differ from that of the bottom one, ensuring smooth electron flow. But that step wasn’t necessary. Their technique for laying down the graphene on the HTL actually changes the work function of the electrode to exactly what they need it to be.

“We got lucky,” says Song. “Our top and bottom electrodes just happen to have the correct work functions as a result of the processes we use to make them.”

Putting the electrodes to the test

To see how well their graphene electrodes would perform in practice, the researchers needed to incorporate them into functioning organic solar cells. For that task, they turned to the solar cell fabrication and testing facilities of their colleague Vladimir Bulović, the Fariborz Maseeh (1990) Professor of Emerging Technology and Associate Dean for Innovation for the School of Engineering.

For comparison, they built a series of solar cells on rigid glass substrates with electrodes made of graphene, ITO, and aluminum (a standard electrode material). The current densities (or CDs, the amount of current flowing per unit area) and power conversion efficiencies (or PCEs, the fraction of incoming solar power converted to electricity) for the new flexible graphene/graphene devices and the standard rigid ITO/graphene devices were comparable. They were lower than those of the devices with one aluminum electrode, but that was a finding they expected.

“An aluminum electrode on the bottom will reflect some of the incoming light back into the solar cell, so the device overall can absorb more of the sun’s energy than a transparent device can,” says Kong.

The PCEs for all their graphene/graphene devices — on rigid glass substrates as well as flexible substrates — ranged from 2.8 percent to 4.1 percent. While those values are well below the PCEs of existing commercial solar panels, they’re a significant improvement over PCEs achieved in prior work involving semitransparent devices with all-graphene electrodes, the researchers say.

Measurements of the transparency of their graphene/graphene devices yielded further encouraging results. The human eye can detect light at wavelengths between about 400 nanometers and 700 nanometers. The all-graphene devices showed optical transmittance of 61 percent across the whole visible regime and up to 69 percent at 550 nanometers. “Those values [for transmittance] are among the highest for transparent solar cells with comparable power conversion efficiencies in the literature,” says Kong.

Flexible substrates, bending behavior

The researchers note that their organic solar cell can be deposited on any kind of surface, rigid or flexible, transparent or not. “If you want to put it on the surface of your car, for instance, it won’t look bad,” says Kong. “You’ll be able to see through to what was originally there.”

To demonstrate that versatility, they deposited their graphene-graphene devices onto flexible substrates including plastic, opaque paper, and translucent Kapton tape. Measurements show that the performance of the devices is roughly equal on the three flexible substrates — and only slightly lower than those made on glass, likely because the surfaces are rougher so there’s a greater potential for poor contact.

The ability to deposit the solar cell on any surface makes it promising for use on consumer electronics — a field that’s growing rapidly worldwide. For example, solar cells could be fabricated directly on cell phones and laptops rather than made separately and then installed, a change that would significantly reduce manufacturing costs.

They would also be well-suited for future devices such as peel-and-stick solar cells and paper electronics. Since those devices would inevitably be bent and folded, the researchers subjected their samples to the same treatment. While all of their devices — including those with ITO electrodes — could be folded repeatedly, those with graphene electrodes could be bent far more tightly before their output started to decline.

Future goals

The researchers are now working to improve the efficiency of their graphene-based organic solar cells without sacrificing transparency. (Increasing the amount of active area would push up the PCE, but transparency would drop.) According to their calculations, the maximum theoretical PCE achievable at their current level of transparency is 10 percent.

“Our best PCE is about 4 percent, so we still have some way to go,” says Song.

They’re also now considering how best to scale up their solar cells into the large-area devices needed to cover entire windows and walls, where they could efficiently generate power while remaining virtually invisible to the human eye.

This research was supported by the Italian energy company Eni S.p.A. as part of the Eni-MIT Alliance Solar Frontiers Center. Eni is a Founding Member of the MIT Energy Initiative.

This article appeared in the Spring 2017 issue of Energy Futures, the magazine of the MIT Energy Initiative.

de MIT News http://ift.tt/2uG7MFH

Understanding tropical rainfall

The Intertropical Convergence Zone (ITCZ), also known as the doldrums, is one of the dramatic features of Earth’s climate system. Prominent enough to be seen from space, the ITCZ appears in satellite images as a band of bright clouds around the tropics. Here, moist warm air accumulates in this atmospheric region near the equator, where the ocean and atmosphere heavily interact. Intense solar radiation and calm, warm ocean waters produce an area of high humidity, ascending air, and rainfall, which is fed by converging trade winds from the Northern and Southern Hemispheres. The convected air forms clusters of thunderstorms characteristic of the ITCZ, releasing heat before moving away from the ITCZ — toward the poles — cooling and descending in the subtropics. This circulation completes the Hadley cells of the ITCZ, which play an important role in balancing Earth’s energy budget — transporting energy between the hemispheres and away from the equator.

However, the position of the ITCZ isn’t static. In order to transport this energy, the ITCZ and Hadley cells shift seasonally between the Northern and Southern Hemispheres, residing in the one that’s most strongly heated from the sun and radiant heat from the Earth’s surface, which on average yearly is the Northern Hemisphere. Accompanying these shifts can be prolonged periods of violent storms or severe drought, which significantly impacts human populations living in its path.

Scientists are therefore keen to understand the climate controls that drive the north-south movement of the ITCZ over the seasonal cycle, as well as on inter-annual to decadal timescales in Earth’s paleoclimatology up through today. Researchers have traditionally approached this issue from the perspective of the atmosphere’s behavior and understanding rainfall, but anecdotal evidence from models with a dynamic ocean has suggested that the ocean’s sensitivity to climate changes could affect the ITCZ’s response. Now, a study from MIT graduate student Brian Green and the Cecil and Ida Green Professor of Oceanography John Marshall from the Program in Atmospheres, Oceans and Climate in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS) published in the American Meteorological Society’s Journal of Climate, investigates the role that the ocean plays in modulating the ITCZ’s position and appreciates its sensitivity when the Northern Hemisphere is heated. In so doing, the work gives climate scientists a better understanding of what causes changes to tropical rainfall.

“In the past decade or so there’s been a lot of research studying controls on the north-south position of the ITCZ, particularly from this energy balance perspective. ... And this has normally been done in the context of ignoring the adjustment of the ocean circulation — the ocean circulation is either forcing these [ITCZ] shifts or passively responding to changes in the atmosphere above,” Green says. “But we know, particularly in the tropics, that the ocean circulation is very tightly coupled through the trade winds to atmospheric circulation and the ITCZ position, so what we wanted to do was investigate how that ocean circulation might feedback on the energy balance that controls that ITCZ position, and how strong that feedback might be.”

To examine this, Green and Marshall performed experiments in a global climate model with a coupled atmosphere and ocean, and observed how the ocean circulation’s cross-equatorial energy transport and its associated surface energy fluxes affected the ITCZ’s response when they imposed an inter-hemispheric heating contrast. Using a simplified model that omitted landmasses, clouds, and monsoon dynamics, while keeping a fully circulating atmosphere that interacts with radiation highlighted the ocean’s effect while minimized other confounding variables that could mask the results. The addition of north-south ocean ridges, creating a large and small basin, mimicked the behavior of the Earth’s Atlantic’s meridional overturning circulation and the Pacific Ocean.

Green and Marshall then ran the asymmetrically heated planet simulations in two ocean configurations and compared the ITCZ responses. The first used a stationary “slab ocean,” where the thermal properties were specified so that it mimicked the fully coupled model before perturbation, but was unable to respond to the heating. The second incorporated a dynamic ocean circulation. By forcing the models identically, they could quantify the ocean circulation’s impact on the ITCZ.

“We found in the case where there’s a fully coupled, dynamic ocean, the northward shift of the ITCZ was damped by a factor of four compared to the passive ocean. So that’s hinting that the ocean is one of the leading controls on the position of the ITCZ,” Green says. “It’s a significant damping of the response of the atmosphere, and the reason behind this can just be diagnosed from that energy balance.”

In the dynamic ocean model, they found that when they heat the simulated ocean-covered planet, eddies export some heat into the tropical atmosphere from the extra-tropics, which causes the Hadley cells to respond — the Northern Hemisphere cell to weaken and the Southern Hemisphere cell to strengthen. This transports heat southward through the atmosphere. Concurrently, the ITCZ shifts northward; associated with this are changes in the trade winds — the surface branch of the Hadley cells — and the surface wind stress near the equator. The surface ocean feels this change in winds, which energizes an anomalous ocean circulation and moves water mass southwards across the equator in both hemispheres, carrying heat with it. Once this surface water reaches the extra-tropics, the ocean pumps it downwards where it returns northward across the equator, cooler and at depth. This temperature contrast between the warm surface cross-equatorial flow and the cooler deeper return flow sets the heat transported by the ocean circulation.

“In the slab ocean case, only the atmosphere can move heat across the equator; whereas in our fully coupled case, we see that the ocean is the most strongly compensating component of the system, transporting the majority of the forcing across the equator.” Green says. “So from the atmosphere’s perspective, it doesn’t even feel the full effect of that heating that we’re imposing. And as a result, it has to transport less heat across the equator and shift the ITCZ less.” Green adds that the response of the large basin ocean circulation broadly mimics the Indian Ocean’s yearly average circulation.

Marshall notes that the ability of the wind-driven ocean circulation to damp ITCZ shifts represents a previously unappreciated constraint on the atmosphere’s energy budget: “We showed that the ITCZ cannot move very far away from the equator, even in very ‘extreme’ climates,” indicating that the position of the ITCZ may be much less sensitive to inter-hemispheric heating contrasts than previously thought.”

Green and Marshall are currently expanding upon this work. With the help of David McGee, the Kerr-Mcgee Career Development Assistant Professor in EAPS, and postdoc Eduardo Moreno-Chamarro, the pair are applying this to the paleoclimate record during Heimrich events, when the Earth experiences strong cooling, looking for ITCZ shifts.

They’re also investigating the decomposition of heat and mass transport between the atmosphere and the ocean, as well as between the Earth’s oceans. “The physics that control each of those oceans’ responses are dramatically different, certainly between the Pacific and the Atlantic oceans,” Green says. “Right now, we’re working to understand how the mass transports of the atmosphere and ocean are coupled. While we know that they’re constrained to overturn in the same sense, they’re not actually constrained to transport an identical amount of mass, so you could further enhance or weaken the damping by the ocean circulation by affecting how strongly the mass transports are coupled.”

de MIT News http://ift.tt/2eVnasp

MIT Haystack Observatory's John Foster named AGU Fellow

John C. Foster, principal research scientist at MIT's Haystack Observatory, has been awarded AGU Fellow status from the American Geophysical Union for 2017. The AGU elects a small group of members to become fellows each year in honor of their scientific leadership and research excellence. Recipients are AGU members who have fundamentally advanced research in their fields of geophysics.

"AGU Fellows are recognized for their scientific eminence in the Earth and space sciences. Their breadth of interests and the scope of their contributions are remarkable and often groundbreaking," the announcement read. "They have expanded our understanding of the Earth and space sciences, from volcanic processes, solar cycles, and deep-sea microbiology to the variability of our climate and so much more. Only 0.1 percent of AGU membership receives this recognition in any given year."

A group of space science colleagues nominated Foster for this award, citing his visionary leadership in space physics research, including transformative insights and work in magnetosphere-plasmasphere-ionosphere coupling, ionospheric storm response, and radiation belt dynamics. A large portion of Foster’s research has been done with ground and space-based observational techniques, including incoherent scatter radar and satellite-borne instruments, using these powerful tools for investigations of the physics of the upper atmosphere and Earth's highly energetic radiation belts. He is an expert in the analysis of data from ionospheric radars at Haystack's Millstone Hill and other facilities. Foster also has been extensively involved in international scientific collaboration with colleagues in China, Ukraine, and Russia.

"John’s excellence and sharp observational eye continues to lead the field in applications of multiple observational points of view from both ground and space remote sensors, creating new insights on the workings of the complicated Sun-Earth system and its dynamics," says Phil Erickson, assistant director at Haystack Observatory. "He is truly outstanding at seeing connections in phenomena that have previously been studied only in isolation."

Broad interests in space science continue today to lead Foster towards innovative and far reaching insights within the vitally important study of cross-scale and cross-disciplinary coupling processes in Earth’s near-space environment. He is an innovator in the application of high-power ionospheric radar systems to the study of plasmas and instabilities in the terrestrial mid-latitude ionosphere.

Foster’s work has taken place across multiple institutions in a career that has lasted more than four decades. After receiving his PhD in physics from the University of Maryland at College Park in 1973, he worked at a number of institutions, including the National Research Council of Canada and Utah State University. In 1983, former Haystack director John Evans recruited Foster to lead its internationally known atmospheric science program. He led this group for more than 30 years, maintaining and significantly growing the scientific and technical staff throughout this time period. He was appointed assistant director of Haystack in 1983 and promoted to principal research scientist in 1988, achieving associate Haystack director status in 1995. Throughout his career, Foster has dedicated much time and effort to mentoring a large number of younger space scientists.

Even beyond this large body of prior work, Foster continues his extensive publication record and a brisk collaboratory pace of fundamental and unique discoveries in space science. His most recent work using data from the twin NASA Van Allen Probes spacecraft was published earlier this year in the AGU's Journal of Geophysical Research Space Physics. The study provides an example of Foster’s innovative observational approach, as he and several colleagues analyzed the nonlinear interactions of ultrarelativistic electrons and very low frequency waves to advance understanding of rapid variations in Earth's outer radiation belt.

de MIT News http://ift.tt/2tQFA4g

Monitoring metabolic energy expenditure, health, and fitness with a breath analyzer

The U.S. military has great interest in more comprehensive measurement and tracking of metabolism, both for optimizing the performance of warfighters under demanding physical conditions and for maintaining the health and wellness of forces during and after their military careers. While sensors for making metabolic measurements have existed for decades, they are expensive, cumbersome instruments primarily intended for clinical or professional use. MIT Lincoln Laboratory, in collaboration with the U.S. Army Research Institute for Environmental Medicine (USARIEM), has undertaken a research effort to create a low-cost personal metabolic sensor and an associated metabolic fuel model. The Carbon dioxide/Oxygen Breath and Respiration Analyzer (COBRA) enables individuals to make on-demand metabolic measurements simply by breathing into it.

“Besides assessing performance of soldiers in the field, the COBRA can be applied to broader purposes, such as training athletes for high-endurance activities, guiding weight loss by quantifying the impact of dietary and exercise regimens, or identifying nutritional imbalances,” says Kyle Thompson, a member of the development team from Lincoln Laboratory’s Mechanical Engineering Group.

Since the early 20th century, scientists have been using indirect calorimetry (IC) to calculate individual energy expenditure and metabolic rates. This method measures the ratio of carbon dioxide to oxygen in exhaled breath, which can be used to measure the levels of carbohydrates and fats being used by the body to meet metabolic energy needs. Information about energy expenditure rates is valuable for setting reasonable physical standards within the military. For example, limits on the distance and speed of foot marches can best be established by quantifying metabolic workloads of soldiers. The Soldier 2020 program is currently employing metabolic energy measurement to help establish job-related fitness requirements.

“For high-performance athletes or active-duty soldiers, optimally matching nutritional intake to the demands of a specific activity can improve performance and increase the likelihood of successful mission completion,” says Gary Shaw, principal investigator on the laboratory’s COBRA team. Physically demanding tasks can lead to glycogen depletion, which has a negative impact on performance. By tracking energy expenditure in real-time, soldiers could detect and avoid the onset of low glucose levels associated with glycogen depletion as well as other metabolic complications, such as heat stress.

While existing mobile IC sensors can make physiological measurements, they are expensive and complex to calibrate since their application has largely been limited to clinical studies, high-performance athletics, and field testing with small groups of subjects over limited periods of time. The COBRA sensor is smaller, simpler to use, and less costly to manufacture than existing IC sensors, enabling the measurement of individual energy expenditure for dozens of soldiers in a military field unit throughout the day. Lincoln Laboratory researchers hope to use such measurements to refine the personalized metabolic fuel model for individuals, track nutritional needs, and assess the impact of training on the individual’s metabolic efficiency and endurance.

“The COBRA system is a breakthrough technology that promises to provide performance comparable to $30,000-$40,000 sensors at a fraction of the cost and with ease of use that makes personal ownership feasible,” Shaw says.

USARIEM is currently testing and evaluating the COBRA sensor by comparing the COBRA measurements against those collected by laboratory-grade instruments. Once the sensor performance has been benchmarked in the laboratory, USARIEM will conduct small field studies to measure energy expenditure and nutrient consumption associated with different training exercises. Following successful field measurements, low-rate production of the COBRA sensor may be pursued in order to study energy expenditure and performance across dozens of soldiers  over days of activity.

Beyond its use in studies of the performance of soldiers and athletes, the COBRA sensor and associated metabolic model can be applied to the management of the general population’s metabolic health. It is anticipated that the COBRA sensor and metabolic model can be used to tailor dietary and exercise regimens for managing weight, inferring blood glucose and glycogen storage levels, and creating public databases on metabolic wellness and trends. This information could be used by clinicians and patients to aid in controlling obesity, which affects over one-third of Americans, and to provide a non-invasive indication of chronically high blood glucose, which is associated with the development of type-2 diabetes. According to the Centers for Disease Control and Prevention, nearly half of the adult population in the United States is either diabetic or pre-diabetic.

There are several promising avenues for the COBRA sensor’s future. The researchers have applied for a patent and plan to conduct single-subject experiments to demonstrate how the sensor can be used in assessing nutritional imbalances. The laboratory will also seek opportunities to collaborate with other researchers interested in using COBRA as a tool in clinical studies, including those concerned with weight loss and endurance training.

de MIT News http://ift.tt/2vbV4Am

Talk science to me

In the spring of 2015, graduate students communicated a clear message to the Department of Electrical Engineering and Computer Science (EECS): They needed help communicating.

Specifically, they wanted to give better pitches for research and startup ideas and make presentations that wowed their colleagues and senior scientists. They also wanted to impress recruiters, who saw plenty of candidates with technical skills, but it was always the applicants with strong communication skills who really stood out from the pack.

Samantha Dale Strasser, a PhD candidate in EECS, says students were particularly stressed during conferences, when they realized their talks weren’t what they could be.

“Coming from MIT, we really want to be not only at the forefront of science, but also the forefront of communicating that science,” says Strasser, who was among the graduate students who provided the 2015 feedback.

In response, the department launched two initiatives: the EECS Communication Lab, a peer-coaching resource, and a new lab-supported class, 6.S977 (Technical Communication). By all accounts, both initiatives have succeeded, resulting not only in improved pitches and posters, but in a stronger department-wide awareness of power of effective communication as well.

The Comm Lab, as it’s affectionately known, employs graduate students and postdocs from across EECS to serve as peer coaches. The coaches have been trained in how to strengthen their own communication skills, including how to consider their audiences and purposes, how to generate excitement about their research, and how to create narrative rather than litanies. As a result, the communication advisors are ready to provide one-to-one help to virtually anyone in the department, including undergraduates, graduate students, and postdocs.

“The Comm Lab is a great resource,” says Priyanka Raina, a PhD candidate in EECS who consulted the lab for a wide range of assignments including a conference paper, a presentation, her resumé, and a faculty package. “It helped me a great deal. All the assignments that I worked on with the lab were accepted or saw positive results. I even got an interview with a top university.”

The EECS Comm Lab is the latest installment of the Communication Lab program, a School of Engineering resource. The departments of Biological Engineering, Chemical Engineering, and Nuclear Science and Engineering also have their own communication labs, as does the Broad Institute of Harvard and MIT. The model has expanded quickly because it serves students at the time when they need it most, says Jaime Goldstein, the program’s former director.

“Early scientists need to get funding, get a job, go to conferences, and meet collaborators,” she says. “We insert ourselves at just that right moment with just the right information. And peer coaches know how to ask the right questions because they're insiders in the field. It’s a real recipe for success.”

Faculty members agree. In addition to that first Technical Communication class, the Comm Lab has hosted workshops and supported other courses. In January of this year, the Comm Lab provided a training session for graduate students presenting at the Microsystems Technology Laboratories’ Microsystems Annual Research Conference.

“Industry members and faculty commented that the quality of pitches showed marked improvement this year,” says Ujwal Radhakrishna, the EECS postdoc who organized the conference.

Research abstracts and presentations in 6.336 (Introduction to Numerical Simulation) have also been notably clearer than in the past, says Luca Daniel, an EECS professor who instructs the Comm Lab-supported class.

“The abstracts felt a lot better organized, with engaging motivations, detailed concise methods and results descriptions, and thoughtful considerations at the end,” Daniel says. “The presentations were also more accessible to a wider audience. My class has students from 12 different departments, so that’s essential.”

Daniel wasn’t the only one enthusiastic about the Comm Lab results in his course. Asked whether he should again use the resource in his course, he says his students also responded with an emphatic “yes.” Students also suggested adding midterm deadlines, in addition to deadlines for final abstracts and presentations, to encourage even earlier visits to the Comm Lab.

“They love the fact that it is other students helping them,” Daniel says.

Diana Chien, the current director of the school-wide Communication Lab program, understands the appeal. “In technical communication, you really can't separate the science or engineering from the communication, so our advisors are ready to tackle both at once,” she says. When EECS clients visit the Comm Lab to work on conference presentations with communication advisors, they’re really connecting with peers. The advisors are “as ready to parse details about the design of a machine-learning algorithm as they are to ask strategic questions about audience and storytelling,” Chien says.

Chien and the communication advisors also created an online resource, the CommKit, to guide students through several common communication tasks, such as a cover letter or a National Science Foundation application. If an impending deadline precludes students from meeting an advisor in person, help is still just a click away.

The Comm Lab’s popularity is growing. Since September 2016, advisors have scheduled more than 300 appointments with 180-plus advisees. More than 270 students attended workshops on posters, pitches, thesis proposals, and the Research Qualifying Exam (RQE). Feedback from the Comm Lab’s first annual survey remarkably showed that of the respondents who had visited the lab, all of them would recommend it to a friend. And while many students and postdocs haven’t yet used the lab, more than three quarters of non-users surveyed indicated they were still glad that EECS offers the service.

School of Engineering Dean Anantha Chandrakasan says the enthusiastic and sustained interest from students and faculty "tells us the program’s doing exceptionally well.”

“I expect the Comm Lab will become a staple resource in the department,” says Chandrakasan, who is also the Vannevar Bush Professor of Electrical Engineering and Computer Science and a former EECS department head.

Chris Foy, a PhD candidate in EECS who took the communication course and is now a peer coach, says skills taught in the Comm Lab have a clear professional impact. He ranks the Technical Communication class as one of his favorites at MIT, in part because it taught him how to focus on building a rationale or a narrative about his research.

“Being able to do this is crucial as a scientist because there are so many problems that are, in theory, worth solving,” he says. “But if you can’t construct a story around why you chose this problem,” he adds pointedly, “then why are you solving it?”

Joel Jean PhD '17, who received a doctorate in electrical engineering in May, credits his communication-advisor training with helping him clearly explain his vision for working on thin-film solar cells to help address climate change. That effort paid off: Jean won one of MIT’s most prestigious graduate awards, the Hugh Hampton Young Fellowship.

“My return on investment from working with the EECS Comm Lab as an advisor has been extraordinarily high,” he says. “And I expect its value, both for me and for students in the department, to keep growing.”

de MIT News http://ift.tt/2w4i9kB

Letter regarding timeline of the Senior House decision

The following letter was submitted to the Tech by Chancellor Cynthia Barnhart today.

To the editor,

Given the high level of interest in facts surrounding the Senior House decision, I thought it might help to lay out the milestone events of the last year and share my thinking. I’ve also posted a detailed set of FAQs.

One note: Since last summer, at the request of Senior House residents, we have not been publically sharing details about issues in the house. This has left many people wondering why our communications seem deliberately vague. While respecting student privacy, I will be as specific as I can.

The milestones:

June 2016 – Our initial decision

Looking at data from the MIT registrar, we discovered that the percentage of Senior House students who were never graduating was much higher than for the student body as a whole (21.1% vs. 7.7%). Among a constellation of concerning issues, this prompted us to close the house to the incoming freshman class, and to launch an effort to promote each Senior House resident’s well-being and personal and intellectual growth. We called this the turnaround. Through the summer, we worked with Senior House students to design the turnaround process.

Fall 2016 – Launch of the turnaround

I appointed a turnaround team of 47 people, including 28 residents and several Senior House alums. Beginning in the fall, we met frequently, as a group and in subcommittees. MIT has a distinctive tradition of involving students in many important decisions about how the Institute is run; in designing the turnaround, this spirit of mutual respect and trust is exactly what we had in mind. We wanted student self-governance to prevail, and we were hopeful that it could produce a healthy result. In fact, as The Tech reported last December, I told house residents that I believed they were on a positive trajectory to have freshmen in the house in September 2017.

Spring 2017 – Progress derailed

Unfortunately, in the spring we received highly credible reports of unsafe and illegal behavior in Senior House. To understand the situation better, we began a formal review, consisting of interviews with house residents as well as extensive ongoing conversations that Dean Nelson and I had with both residents and house leaders.

April-May 2017 – The review

The review made clear that multiple students had engaged in unsafe, illegal behavior, on multiple occasions. Importantly, it revealed a prevailing environment that enabled and even encouraged such behavior. We also learned that some students who were troubled by the illegal behavior felt silenced by members of the Senior House community. Together these signs told us that Senior House self-governance was broken. We concluded that the turnaround had failed. We thought it might still be possible to restore self-governance and allow members of the Senior House community who were not involved in or accepting of the troubling behavior to create a fresh version of the house: a reset.

June 12, 2017 – The reset

Because a subset of residents was determined to keep Senior House unchanged, the only hope for a reset to succeed was to ask everyone to leave and reapply. So on June 12th, we did. However, as the process began, prospective new residents reported facing personal pressure from some Senior House residents and alumni about how they should behave, as well as an intensive campaign to reconstitute the Senior House status quo. Undermined in this way, the reset was bound to fail, too.

July 7, 2017 – Our decision to use the building as graduate housing

Our fundamental obligations to student safety and well-being forced us to choose a new path. Judging that a community of graduate students would be better able to withstand outside pressure and create a new culture of their own, we decided to use the building to house graduate students only. As I explained in a July 11 letter to undergraduates, we had run out of workable and realistic options. We had to close the house and start again.

Both students and alumni have raised questions about whether a residential community should be disrupted because some of its members behaved badly. But I hope you can see that the issues ran deeper than that. This was not about any single incident, or just a couple of students who broke the rules. And it was certainly not a verdict on east side culture. More broadly, it was about a house environment that made it impossible for us to move forward constructively, even with those residents willing to work with us in good faith. And it was about a loss of trust, including with individuals we thought were committed to the turnaround.

I know this decision has caused deep distress for many people. And it was not the outcome we spent a year striving to achieve. One of its painful consequences is the elimination of a space on campus that has been very important to our LBGTQ+ students. We are working actively with all residents to make sure they each find a welcoming living situation and to ensure that the staff in every residence is trained to understand issues they may face. We are also starting work with LBGTQ+ student leaders to find new ways to support their community.

One final note: I have not referred to the 2015 Healthy Minds study. It was not relevant to any of our decisions this year. If you have questions about it, you can read more in the FAQs. I am certain some in the MIT community disagree with our conclusions. But I hope it is clear to everyone that we take to heart our responsibility for student well-being, pay close attention to all the input we receive, seek and weigh every available option, and make our best judgments – with our students at the center of the process, and at the center of our thoughts.

Respectfully,

Cynthia Barnhart PhD ’88

de MIT News http://ift.tt/2vNfNaB

Ultracold molecules hold promise for quantum computing

Researchers have taken an important step toward the long-sought goal of a quantum computer, which in theory should be capable of vastly faster computations than conventional computers, for certain kinds of problems. The new work shows that collections of ultracold molecules can retain the information stored in them, for hundreds of times longer than researchers have previously achieved in these materials.

These two-atom molecules are made of sodium and potassium and were cooled to temperatures just a few ten-millionths of a degree above absolute zero (measured in hundreds of nanokelvins, or nK). The results are described in a report this week in Science, by Martin Zwierlein, an MIT professor of physics; Jee Woo Park, a former MIT graduate student; Sebastian Will, a former research scientist at MIT and now an assistant professor at Columbia University, and two others, all at the MIT-Harvard Center for Ultracold Atoms.

Many different approaches are being studied as possible ways of creating qubits, the basic building blocks of long-theorized but not yet fully realized quantum computers. Researchers have tried using superconducting materials, ions held in ion traps, or individual neutral atoms, as well as molecules of varying complexity. The new approach uses a cluster of very simple molecules made of just two atoms.

“Molecules have more ‘handles’ than atoms,” Zwierlein says, meaning more ways to interact with each other and with outside influences. “They can vibrate, they can rotate, and in fact they can strongly interact with each other, which atoms have a hard time doing. Typically, atoms have to really meet each other, be on top of each other almost, before they see that there's another atom there to interact with, whereas molecules can see each other” over relatively long ranges. “In order to make these qubits talk to each other and perform calculations, using molecules is a much better idea than using atoms,” he says.

Using this kind of two-atom molecules for quantum information processing “had been suggested some time ago,” says Park, “and this work demonstrates the first experimental step toward realizing this new platform, which is that quantum information can be stored in dipolar molecules for extended times.”

“The most amazing thing is that [these] molecules are a system which may allow realizing both storage and processing of quantum information, using the very same physical system,” Will says. “That is actually a pretty rare feature that is not typical at all among the qubit systems that are mostly considered today.”

In the team’s initial proof-of-principle lab tests, a few thousand of the simple molecules were contained in a microscopic puff of gas, trapped at the intersection of two laser beams and cooled to ultracold temperatures of about 300 nanokelvins. “The more atoms you have in a molecule the harder it gets to cool them,” Zwierlein says, so they chose this simple two-atom structure.  

The molecules have three key characteristics: rotation, vibration, and the spin direction of the nuclei of the two individual atoms. For these experiments, the researchers got the molecules under perfect control in terms of all three characteristics — that is, into the lowest state of vibration, rotation, and nuclear spin alignment.

“We have been able to trap molecules for a long time, and also demonstrate that they can carry quantum information and hold onto it for a long time,” Zwierlein says. And that, he says, is “one of the key breakthroughs or milestones one has to have before hoping to build a quantum computer, which is a much more complicated endeavor.”

The use of sodium-potassium molecules provides a number of advantages, Zwierlein says. For one thing, “the molecule is chemically stable, so if one of these molecules meets another one they don't break apart.”

In the context of quantum computing, the “long time” Zwierlein refers to is one second — which is “in fact on the order of a thousand times longer than a comparable experiment that has been done” using rotation to encode the qubit, he says. “Without additional measures, that experiment gave a millisecond, but this was great already.” With this team’s method, the system’s inherent stability means “you get a full second for free.”

That suggests, though it remains to be proven, that such a system would be able to carry out thousands of quantum computations, known as gates, in sequence within that second of coherence. The final results could then be “read” optically through a microscope, revealing the final state of the molecules.

“We have strong hopes that we can do one so-called gate — that's an operation between two of these qubits, like addition, subtraction, or that sort of equivalent — in a fraction of a millisecond,” Zwierlein says. “If you look at the ratio, you could hope to do 10,000 to 100,000 gate operations in the time that we have the coherence in the sample. That has been stated as one of the requirements for a quantum computer, to have that sort of ratio of gate operations to coherence times.”

“The next great goal will be to ‘talk’ to individual molecules. Then we are really talking quantum information,” Will says. “If we can trap one molecule, we can trap two. And then we can think about implementing a ‘quantum gate operation’ — an elementary calculation — between two molecular qubits that sit next to each other,” he says.

Using an array of perhaps 1,000 such molecules, Zwierlein says, would make it possible to carry out calculations so complex that no existing computer could even begin to check the possibilities. Though he stresses that this is still an early step and that such computers could be a decade or more away, in principle such a device could quickly solve currently intractable problems such as factoring very large numbers — a process whose difficulty forms the basis of today’s best encryption systems for financial transactions.

Besides quantum computing, the new system also offers the potential for a new way of carrying out precision measurements and quantum chemistry, Zwierlein says.

“These results are truly state of the art,” says Simon Cornish, a professor of physics at Durham University in the U.K., who was not involved in this work. The findings “beautifully reveal the potential of exploiting nuclear spin states in ultracold molecules for applications in quantum information processing, as quantum memories and as a means to probe dipolar interactions and ultracold collisions in polar molecules,” he says. “I think the results constitute a major step forward in the field of ultracold molecules and will be of broad interest to the large community of researchers exploring related aspects of quantum science, coherence, quantum information, and quantum simulation.”

The team also included MIT graduate student Zoe Yan and postdoc Huanqian Loh. The work was supported by the National Science Foundation, the U.S. Air Force Office of Scientific Research, the U.S. Army Research Office, and the David and Lucile Packard Foundation.

de MIT News http://ift.tt/2uCk1mW

SproutsIO aims to power a “Personal Produce” movement

MIT Media Lab alumna Jennifer Broutin Farah SM ’13, CEO and co-founder of SproutsIO, has spent nearly a decade innovating in urban farming, designing small- and large-scale gardening systems that let anyone grow food, anywhere, at any time.

All this work will soon culminate with the commercial release of her startup’s smart, app-controlled microgarden that lets consumers optimize, customize, and monitor the growth of certain fruits, vegetables, and herbs year-round. Moreover, the soil-free system uses only 2 percent of the water and 40 percent of the nutrients typically used for soil-grown plants.

After piloting the system in Boston homes and restaurants, and following a successful Kickstarter campaign last fall, SproutsIO is ramping up production and hitting the shelves in a few months. Philosophically, the aim is to power a “personal produce” movement, Farah says, in which more people grow their own food, encouraging healthier eating and cutting down on waste.

“Over the last 60 years, we’ve gotten out of touch with growing our food,” Farah says. “But when you grow your own food, you care more about what happens to it. You’re not going to throw it away, you’re going to know exactly what’s going into your plants, you’re going to share your food with friends and family. It gives a new meaning to produce.”

Customized plants

Tailoring plants for taste preferences may not be well-known outside of the wine-making world, where grapes are grown under specific climatic conditions to produce specific flavors. But produce and herbs have similar peculiarities. Even within a given species or variety, individual plants can have different characteristics and growing needs.

“Most of that is dependent on the environment,” Farah says. “If you can customize the lighting, the water, and the nutrients, you can really optimize certain variations in the plants, according to how you want them to taste. SproutsIO can reproduce these specific climatic conditions to a very precise degree.”

SproutsIO consists of a growing device, which is a large basin with a curving, overhead adjustable lamp attached; a replaceable and compostable “sIO” seed refill with growing media, seeds, and nutrients, that’s dropped into the growing device; and “SproutsIOGrow” software that includes a mobile app that collects and analyzes growth data and controls the system. Currently, the system supports basil, kale, wheatgrass, arugula, eggplant, peppers, tomatoes, tea, and a variety of plants from root vegetables to fruiting plants.

The SproutsIO system has a number of innovations developed by the startup, stemming from early research at MIT. The hybrid hydroculture system, for instance, consists of “hydroponic” and “aeroponic” growing, where roots are submerged in or misted with water and nutrients. Varying the watering process optimizes water and nutrient use while supporting the growth of different plants at different phases. A tomato plant, for instance, grows large roots during the fruiting stage. The system can lift the plant up at that time to let the roots grow larger, but still deliver water and nutrients by misting.

There’s also a custom LED light that automatically adjusts, depending on need. If the device is located near a window, where sunlight is plentiful, the light will dim; if the sunlight diminishes or if the device is placed in darker areas, the light shines brighter. The system uses about half the electricity of a 60-watt incandescent light bulb.

Sensors monitor plant growth and transmit data to what Farah calls the “backbone” of the system: SproutsIOGrow. The app lets users customize their plants and monitor the plant’s growth in real-time. Depending on light and nutrients added, for instance, tomatoes can be grown to taste sweeter or more savory.

The app also provides predictive growth cycles and connects to personal activity trackers, meal planners, and calendars to help with meal scheduling. A built-in camera takes regular snapshots of growing plants for health diagnostics and to create time-lapse images for users on the app.

Growing plants in such a controlled environment boosts growth efficiency by six times and cuts the length of growth cycles by 50 percent over traditional gardening, according to the startup.

Farah says people often ask her if all the technology tends to remove people from the growing process. It’s the exact opposite, she says: “Technology creates a whole new lens on the growing process. Most of us don’t understand how plants grow because they exist on a totally different time scale. But we show people how the plants grow over time and how they react to certain changes. That’s really eye-opening.”

Shrinking greenhouses

Today’s SproutsIO system is the product of years of refinement for mass adoption. In 2009, while working for New York City’s Department of Parks and Recreation, Farah designed a “vertically integrated greenhouse” system, called the Façade Farm. The system consisted of a large metal frame that could be affixed to the side of a building. Long metal planters were installed inside like shelves, and a pump system was installed on the floor. The boxes could be placed up and down a building like gardening balconies.

Though never fully realized, the system got Farah thinking about bringing growing systems to urban areas — a concept that’s popular now but was fairly novel at the time. Building massive structures, however, was a time-consuming and complex process. In 2011, Farah enrolled in the Media Lab, in the Changing Places Group, to develop the idea on a smaller scale.

For her master’s thesis, she built a slightly smaller indoor aeroponic system, called SeedPod, that consisted of modular planters made of inflatable plastic and suspended in three tiers by steel rods. The planters were equipped with sensors for monitoring the plants. An automated pump provided water and nutrients to each planter.

Partnering with Boston Public Schools, Farah installed the system in a middle school in Roxbury. Students started growing plants to eat, and teachers incorporated the gardening into their lessons. “It clicked that the more involved people are with growing food, the more they cared about what happened to it,” she says.

In 2012, Farah shrunk the system further, developing a microgardening “station” that could be used in homes. A number of growing pods — moving toward today’s SproutsIO device — were attached to a vertical pole at different levels, resembling a tree of pods. Included were early versions of the misting system, lighting, and sensors viewed through an app.

In 2013, Farah launched SproutsIO and entered the project into the $100K Entrepreneurship Competition, where she was a semifinalist, and a Founders.org entrepreneurship competition, which she won. Through MIT Sloan School of Management and Media Lab venture-based classes, she honed the business idea and fleshed out her startup’s larger “personal produce” mission. “Those courses were very inspiring classes that helped to get students thinking about how their ideas apply to larger world context,” she says.

Years of user feedback and research and development helped the startup refine the product into today’s SproutsIO system. Early prototypes, in fact, were sent to Barbara Lynch, a renowned Boston chef who is now advisor to the startup. “What better way to really understand how well the system can perform than putting it in a professional chef’s kitchen?” Farah says. SproutsIO continues to work with a number of professional chefs across the nation.

Ultimately, however, what benefit does a smart microgarden offer over simply growing potted plants at home? “At a base level, we make it easier for people to start growing,” Farah says. But she also believes the system is “a small-scale solution that can have a big impact.”

Individual SproutsIO units can save consumers water, energy, and resources, while easing them into growing their own food. If enough people adopt the system, she says, it could save significant amounts of water and encourage local, efficient growing. But the concept of optimized watering systems, if designed at scale, could also benefit a world where around 70 percent of fresh water is used for industrial agricultural, she adds.

“We need to be considering different solutions for growing that start to optimize the needs of the plant, rather than just pouring tons of water and nutrients on them,” she says.

de MIT News http://ift.tt/2uzispS

Featured video: A self-driving wheelchair

Singapore and MIT have been at the forefront of autonomous vehicle development. First, there were self-driving golf buggies. Then, an autonomous electric car. Now, leveraging similar technology, MIT and Singaporean researchers have developed and deployed a self-driving wheelchair at a hospital. 

Spearheaded by Daniela Rus, the Andrew (1956) and Erna Viterbi Professor of Electrical Engineering and Computer Science and director of MIT’s Computer Science and Artificial Intelligence Laboratory, this autonomous wheelchair is an extension of the self-driving scooter that launched at MIT last year — and it is a testament to the success of the Singapore-MIT Alliance for Research and Technology, or SMART – a collaboration between researchers at MIT and in Singapore.

Rus, who is also the principal investigator of the SMART Future Urban Mobility research group, says this newest innovation can help nurses focus more on patient care as they can get relief from logistics work which includes searching for wheelchairs and wheeling patients in the complex hospital network.

"When we visited several retirement communities, we realized that the quality of life is dependent on mobility. We want to make it really easy for people to move around," Rus says.

Submitted by: Pauline Teo/SMART | Video by: SMART | 3 min, 3 sec

de MIT News http://ift.tt/2w17RSg

El nuevo aeropuerto internacional de Pekín toma forma

Las batallas por los mejores y más grandes aeropuertos continúan en el mundo de la aviación con la coronación hace unos días de la estructura de acero de la terminal principal del nuevo aeropuerto internacional de Pekín. 

Este impresionante aeropuerto ha sido diseñado por el estudio Zaha Hadid Architects y la empresa francesa especializada en ingeniería aeroportuaria ADP Ingénierie. 

Actualmente, la enorme estructura de acero cuenta con 313.000 metros cuadrados y ha sido diseñado para soportar un volumen anual de 620.000 vuelos el tráfico, 100 millones de pasajeros y 4 millones de toneladas de carga. Así mismo, contará con siete pistas de aterrizaje, 78 puertas e incluirá un hotel.

A la hora de desarrollar este proyecto se ha contado que sea un aeropuerto adaptable y sostenible, además de instalarse lo último en tecnología ecointeligente como paneles solares, transportación eléctrica en su interior y un sistema de reciclaje de agua y desechos.

Esta megaconstrucción con forma de estrella será un centro clave dentro de la creciente red de transporte de Beijing al contar con un centro de transporte de 80.000 metros cuadrados con enlaces directos a los servicios ferroviarios locales y nacionales, incluyendo el tren de alta velocidad Gaotie.

Con lo que respecta al diseño de las cinco alas del aeropuerto, en la cultura china representa a la seda, al té, a la porcelana, a la tierra de labranza y el jardín chino.

Además el recinto incluirá jardines y áreas separadas para pasajeros de vuelos internacionales y nacionales en un intento por reducir las filas de espera y crear un espacio más compacto.

Una de las características únicas que tendrá este aeropuerto, es la corta distancia que habrá en cada una de las alas al edificio central sin superar los 600 metros. Este diseño se diferencia de otros grandes aeropuertos internacionales del mundo porque estos obligan a caminar largas distancias a los pasajeros.

El aeropuerto se sitúa a 46 kilómetros al sur del centro de la capital china y se está construyendo allí para aliviar la presión sobre el abarrotado Aeropuerto Internacional de Capital de Beijing, localizado en el noreste de la urbe.

IMAGENES

de MOS INGENIEROS - BLOG DE INGENIERÍA http://ift.tt/2uy8Ues