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Wednesday, November 13th, 2013

    Time Event
    5:00a
    An economist with a goal
    Soccer puts a smile on Jonathan Tebes’ face, but a mention of economics or international development — or better yet, both at once — will keep him talking animatedly for hours. An MIT senior majoring in economics and minoring in public policy with a focus on development economics, Tebes is passionate about using economic theory in practice to alleviate poverty and improve lives.

    It was on a soccer field — one in his hometown of Hamden, Conn. — that Tebes was introduced at an early age to the face of poverty.

    “I played soccer with one of my good friends since I was about 8 years old, and he grew up poor in inner-city New Haven,” recounts Tebes, who is now MIT’s varsity soccer captain. “At times his family was homeless, and so my family would take him in. This experience really taught me that when you’re not given as many resources it’s very hard for you to succeed up to your potential. Although my friend is beating the odds, that’s not true for so many who grow up poor.”

    Additionally, Tebes heard stories from his family of his grandparents’ imprisonment in concentration camps during World War II, and of their eventual release and immigration to Canada, then America. “They struggled to give their children a new life, and I’m part of the result of that new life,” Tebes says.

    Tebes decided he had found his calling. “I wanted to find a way of addressing poverty,” he says. “Economics is a great way of doing just that.”

    After being recruited for MIT soccer during his junior year of high school, Tebes began looking into the academic opportunities at the Institute — and decided it was the perfect place for him.

    “It was the economics program that really drew me to this school,” he says. “I realized that the opportunities I would have here are unparalleled at any other university in terms of learning economics theory and application.”

    Making a difference with economics

    Tebes dove into economics coursework at the Institute and began conducting research with professor of economics Jonathan Gruber during his sophomore year. Most recently, he worked with Gruber on a new method of evaluating quality of care in hospitals.

    “There’s usually a problem of determining which hospitals are performing well, because if you have a severe illness you tend to go to the hospital that’s the best at treating the illness, so those who give very high-quality care get people who tend to be sicker,” Tebes explains. “Therefore, if you just look at outcomes, it’s hard to tell which hospitals are performing better than others.”

    Gruber’s new method of evaluation attempts to cut out some of the selection bias by focusing on outcomes among patients who were taken by ambulance to the hospital. “That simulates a quasi-random experiment,” Tebes explains. “There’s less choice involved; patients from the same neighborhood often end up going to different hospitals based on what ambulance company picks them up. This allows us to more accurately assess hospital quality.”

    While assisting Gruber with research, Tebes pursued his interest in poverty by taking classes at the Abdul Latif Jameel Poverty Action Lab taught by Abhijit Banerjee, the Ford International Professor of Economics, and Esther Duflo, the Abdul Latif Jameel Professor of Poverty Alleviation and Development Economics. “I was really inspired by Professor Banerjee and Professor Duflo’s book, ‘Poor Economics,’” Tebes says. After taking a course with each of them, Tebes became interested in international development.

    Tebes followed his budding interest to an internship at the World Bank in Washington the summer after his sophomore year, where he studied youth unemployment and entrepreneurship in sub-Saharan Africa. “This internship confirmed my interest in development economics, but I hadn’t experienced any development on the ground,” Tebes says.

    For a hands-on approach to development, Tebes took a class at the MIT Development Lab, or D-Lab, which culminated in a trip to Tanzania during the winter of his junior year. “Traveling to Tanzania reaffirmed my interest in international development,” Tebes said. “I really saw what challenges people face day to day.”

    Innovation in Tanzania

    While in Tanzania, Tebes met Bernard Kiwia, an inventor who has spent time at MIT as a “Designer in Residence” at D-Lab. “I developed a connection with Bernard — he’s a really inspiring person. He’s someone who cares so much about his work, and is very good at it, too,” Tebes says.

    An MIT Public Service Center Fellowship funded Tebes’ return this past summer to Tanzania, where he lived and worked with Kiwia to create an innovation center, called Accelerating Innovation and Social Entrepreneurship, for community youth to participate in creation of low-cost technologies. One of Kiwia’s latest innovations, a motorcycle-powered multi-crop thresher, was the focus of Tebes’ economic research.

    “His thresher attaches to the back of a motorcycle and threshes rice close to industrial throughput, which is really exciting,” Tebes says. “I collaborated with other D-Lab students to conduct a quasi-economic analysis of whether this could benefit farmers. We discovered that it will cost a small farm about one season’s profit to pay for the device, but the device will last for many seasons. Overall, it would cost farmers less than what many already paid casual laborers to thresh their rice and allow them to compete with medium- and large-scale farms.”

    As Tebes became a part of the village community — joining the soccer team, visiting the local market, and learning Swahili — he gained insight into the bigger picture of poverty.

    “What I realized is that community really is the buffer for the negative impacts of poverty. Through the community, people feel valued, protected and supported,” Tebes says. “That’s something that I want to bring back to the U.S., and it will motivate some of my research later on: finding ways to harness community to improve lives.”
    10:00a
    Better batteries through biology?
    Lithium-air batteries have become a hot research area in recent years: They hold the promise of drastically increasing power per battery weight, which could lead, for example, to electric cars with a much greater driving range. But bringing that promise to reality has faced a number of challenges, including the need to develop better, more durable materials for the batteries’ electrodes and improving the number of charging-discharging cycles the batteries can withstand.

    Now, MIT researchers have found that adding genetically modified viruses to the production of nanowires — wires that are about the width of a red blood cell, and which can serve as one of a battery’s electrodes — could help solve some of these problems.

    The new work is described in a paper published in the journal Nature Communications, co-authored by graduate student Dahyun Oh, professors Angela Belcher and Yang Shao-Horn, and three others. The key to their work was to increase the surface area of the wire, thus increasing the area where electrochemical activity takes place during charging or discharging of the battery.

    The researchers produced an array of nanowires, each about 80 nanometers across, using a genetically modified virus called M13, which can capture molecules of metals from water and bind them into structural shapes. In this case, wires of manganese oxide — a “favorite material” for a lithium-air battery’s cathode, Belcher says — were actually made by the viruses. But unlike wires “grown” through conventional chemical methods, these virus-built nanowires have a rough, spiky surface, which dramatically increases their surface area.

    Belcher, the W.M. Keck Professor of Energy and a member of MIT’s Koch Institute for Integrative Cancer Research, explains that this process of biosynthesis is “really similar to how an abalone grows its shell” — in that case, by collecting calcium from seawater and depositing it into a solid, linked structure.


    The increase in surface area produced by this method can provide “a big advantage,” Belcher says, in lithium-air batteries’ rate of charging and discharging. But the process also has other potential advantages, she says: Unlike conventional fabrication methods, which involve energy-intensive high temperatures and hazardous chemicals, this process can be carried out at room temperature using a water-based process.

    Also, rather than isolated wires, the viruses naturally produce a three-dimensional structure of cross-linked wires, which provides greater stability for an electrode.

    A final part of the process is the addition of a small amount of a metal, such as palladium, which greatly increases the electrical conductivity of the nanowires and allows them to catalyze reactions that take place during charging and discharging. Other groups have tried to produce such batteries using pure or highly concentrated metals as the electrodes, but this new process drastically lowers how much of the expensive material is needed.

    Altogether, these modifications have the potential to produce a battery that could provide two to three times greater energy density — the amount of energy that can be stored for a given weight — than today’s best lithium-ion batteries, a closely related technology that is today's top contender, the researchers say.

    Belcher emphasizes that this is early-stage research, and much more work is needed to produce a lithium-air battery that’s viable for commercial production. This work only looked at the production of one component, the cathode; other essential parts, including the electrolyte — the ion conductor that lithium ions traverse from one of the battery’s electrodes to the other — require further research to find reliable, durable materials. Also, while this material was successfully tested through 50 cycles of charging and discharging, for practical use a battery must be capable of withstanding thousands of these cycles.

    While these experiments used viruses for the molecular assembly, Belcher says that once the best materials for such batteries are found and tested, actual manufacturing might be done in a different way. This has happened with past materials developed in her lab, she says: The chemistry was initially developed using biological methods, but then alternative means that were more easily scalable for industrial-scale production were substituted in the actual manufacturing.

    Jie Xiao, a research scientist at the Pacific Northwest National Laboratory who was not involved in this work, calls it “a great contribution to guide the research on how to effectively manipulate” catalysis in lithium-air batteries. She says this “novel approach … not only provides new insights for lithium-air batteries,” but also “the template introduced in this work is also readily adaptable for other catalytic systems.”

    In addition to Oh, Belcher, and Shao-Horn, the work was carried out by MIT research scientists Jifa Qi and Yong Zhang and postdoc Yi-Chun Lu. The work was supported by the U.S. Army Research Office and the National Science Foundation.

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