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Tuesday, August 30th, 2016
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Event |
| 5:00a |
Reducing runoff pollution by making spray droplets less bouncy When farmers spray their fields with pesticides or other treatments, only 2 percent of the spray sticks to the plants. A significant portion of it typically bounces right off the plants, lands on the ground, and becomes part of the runoff that flows to streams and rivers — often causing serious pollution. But a team of MIT researchers aims to fix that.
By using a clever combination of two inexpensive additives to the spray, the researchers found they can drastically cut down on the amount of liquid that bounces off. The findings appear in the journal Nature Communications, in a paper by associate professor of mechanical engineering Kripa Varanasi, graduate student Maher Damak, research scientist Seyed Reza Mahmoudi, and former postdoc Md Nasim Hyder.
Previous attempts to reduce this droplet bounce rate have relied on additives such as surfactants, soaplike chemicals that reduce the surface tension of the droplets and cause them to spread more. But tests have shown that this provides only a small improvement; the speedy droplets bounce off while the surface tension is still changing, and the surfactants cause the spray to form smaller droplets that are more easily blown away.
The new approach uses two different kinds of additives. The spray is divided into two portions, each receiving a different polymer substance. One gives the solution a negative electric charge; the other causes a positive charge. When two of the oppositely-charged droplets meet on a leaf surface, they form a hydrophilic (water attracting) “defect” that sticks to the surface and increases the retention of further droplets.
Leaves of many plants have a natural tendency to be hydrophobic (water repelling), which is why they often cause droplets to bounce away. But creating these tiny hydrophilic bumps on the leaf surface strongly counteracts that tendency, the team found.
When the MIT team began studying the problem of pesticide runoff, which is a major agricultural problem worldwide, they soon realized that part of the reason for the limited success of earlier attempts to address the problem was that the droplet bouncing happens so quickly, in a matter of milliseconds. That means that most countermeasures, especially those based on chemical properties, just didn’t have time to make much of a difference. “So we thought, what else can you do? And we started playing around with charge interactions,” Varanasi says.
They found that the combination of the two different polymer additives “can pin the droplets” to the surface, “and this all happens during the time it’s spreading,” before the droplets starts a retraction that leads to their bouncing away, according to Varanasi.
The project was developed in collaboration with the MIT Tata Center for Technology and Design, which aims to develop technologies that can benefit communities in India as well as throughout the developing world. Spraying of pesticides there is typically done manually with tanks carried on farmers’ backs, and since the cost of pesticides can be a significant part of a farmer’s budget, reducing the amount that’s wasted could improve the overall economics of the small-farming business, while also reducing soil and water pollution. Decreasing the amount of pesticide sprayed can also reduce the exposure of farmers to the spray chemicals.
Based on the laboratory tests, the team estimates that the new system could allow farmers to get the same effects by using only 1/10 as much of the pesticide or other spray. And the polymer additives themselves are natural and biodegradable, so will not contribute to the runoff pollution.
The new approach would require only minor changes to the existing equipment that farmers use, to separate the pesticide into two streams to which small amounts of each polymer could be added. The polymers themselves are extracted from common, low-cost materials that could be produced locally.
“We can use normal sprayers, with two tanks at a time, and add one material to one tank and the oppositely-charged material to the other,” Damak says. The farmer “would do everything as usual, just adding our solutions.”
The researchers are also experimenting with different sprayer designs that could simplify the process further, potentially eliminating the need for two separate tanks.
The next step, Damak says, is to take the results that have been demonstrated at a laboratory scale and develop them into a practical system that can easily be implemented in the field, and then carry out real-world tests on small farms in India. The team plans to carry out these tests during the coming year. Damak already has traveled through India to see exactly how small farmers are carrying out their spraying currently. “That helped me see what the conditions are on the farms and what they use for their spraying applications,” he says.
The new system “should be easy to implement, and it doesn’t require extra equipment,” he says.
In addition to pesticide spraying, the same approach could be useful in other applications, such as the spraying of water onto plants to prevent frost damage in places like Florida, where citrus crops can be severely damaged by frost but water supplies are already constrained.
The research was supported by the MIT Tata Center for Technology and Design. | | 10:30a |
President Reif to Class of 2020: “All of us together will make a better world” “I hope you will join us in facing the challenge of building a better MIT — and a better world,” MIT President L. Rafael Reif told the Class of 2020 at yesterday's Freshman Convocation, the annual welcoming ceremony for Institute’s incoming undergraduates.
President Reif joined three professors — who are also MIT alumni — in offering words of wisdom and encouragement to the new students, about finding personal and academic success during their time at the Institute.
Humanity, Reif said, is facing serious challenges in areas such as climate change, energy, disease, and poverty. “And MIT is a magnificent human machine for inventing the future. But MIT invents the future thanks to its students … which is why we are we are lucky to have you. And all of us together will make a better world,” Reif said.
The welcoming ceremony was held in a large tent in front of Kresge Auditorium and featured a performance of the song “In Praise of MIT” by the MIT Chorallaries, a student a cappella group. Reif personally greeted the new students and their families at the end of the convocation, and the students then proceeded to introductory luncheons at their residence halls. In March, the Institute admitted 1,485 students from 49 states and 65 countries to the Class of 2020.
Ed Boyden ’99, SM ’99, an associate professor of biological engineering and brain and cognitive sciences, and a member of MIT’s Media Lab and McGovern Institute for Brain Research, told the freshmen to look at MIT through two lenses: “One lens is about you, how you can use MIT to know yourself and figure out how you’re going to change the world. The other lens is about everybody else, how you can use MIT to fill your life with serendipity and unpredictable greatness.”
Addressing lens one, Boyden said MIT is a great place to experiment with “constructive failure,” where failing with certain concepts sets a student on a different but more valuable path. Experimenting with undergraduate research on quantum computers and topics “that didn’t fit into clean disciplinary boxes,” for instance, led Boyden to help pioneer optogenetics, a novel technique that allows scientists to stimulate or silence neurons with light. “I wouldn’t have gone down that path if I hadn’t treated MIT as a laboratory of constructive failure,” he said.
For lens two, Boyden related an anecdote about a serendipitous experience at MIT. As an undergraduate, he taught advanced quantum physics to freshmen, with a professor. Years later, a student who had joined the group of that professor on Boyden's recommendation, later joined Boyden’s research group as a postdoctoral scholar. Together, they co-developed a concept to physically swell biological specimens until they were big enough to visibly identify their molecular building blocks. Two other students later joined Boyden's group, and made the idea a reality. A few months ago, Boyden launched a startup based on that research. “MIT is an engine for creating serendipity,” he said.
Nergis Mavalvala PhD ’97, the Curtis and Kathleen Marble Professor of Astrophysics and the associate department head of the Department of Physics, who played a key role in this year’s discovery of gravitational waves using the Laser Interferometer Gravitational-wave Observatory (LIGO), spoke to students about the importance of problem sets — and embracing learning experiences beyond problem sets.
Mavalvala opened with the story about the origins of LIGO, invented at MIT by Rainer Weiss as a teaching exercise. In the 1960s, Weiss taught an MIT course on Einstein’s theory of general relativity, which included the concept of gravitational waves. To detect gravitational waves, he proposed a method to measure the time it takes light to travel between freely floating masses in space. A gravitational wave would change that time. Problem sets he designed for his students included the equations for those measurements, some of which would inspire Weiss to invent LIGO.
“All of you will do many, many problem sets,” Mavalvala said. Even though sometimes students will struggle through problem sets, “I want you to know that … you may be inventing a Nobel-prize-winning idea, so take your problem sets seriously,” she said to enthusiastic applause from the audience.
But, Mavalvala said, “there’s another piece to education, and that’s the arts and the humanities.” She told the freshmen to take classes they never thought of taking, such as poetry or music classes. “Go beyond problem sets,” she said. “One thing I ask of every one of the students is to do one thing at MIT you never planned to do.”
The event’s final speaker, Lawrence Sass SM ’94, PhD ’00, an associate professor of architecture, extended a challenge to the new students: “I challenge all of the freshmen to graduate with three cell numbers of your professors.”
Getting to know faculty well enough to get their cell phone numbers is important to academic and personal success, Sass said. “It means that [the faculty members] know your story,” he said. “It means that they are here to support you, and they are here to help you build your future.”
Sass noted three good qualities to look for in faculty advisors: They explain and guide students through MIT’s sometimes complex academic system, they connect students with faculty members and others around campus that can help students succeed, and they offer honest and constructive feedback.
He also laid out three key methods for getting to know faculty: Take a small class with the faculty, participate in the Undergraduate Research Opportunities Program, and ask the faculty member out to coffee or lunch. “I strongly consider you to think about ways to get to know your professors,” he said. “I can guarantee that even if you … just get one cell phone number, that cell phone number will last you for a very long time.”
In closing, Sass told the freshmen that he welcomes the opportunity to get to know them personally, not just academically: “That’s probably, for me, the best part of being here: getting to know you outside of the classroom.” | | 10:30a |
GE joins MIT Energy Initiative to develop advanced technology solutions for transforming global energy systems
The MIT Energy Initiative announced today that GE will be joining MITEI as a Sustaining Member to fund advanced technology solutions to help transform global energy systems. GE will commit a total of $7.5 million over a five-year period ($1.5 million annually) and play an active role in MITEI’s research and project priorities. Specifically, GE will participate in four of MITEI’s Low-Carbon Energy Centers to advance research and development in key technology areas for meeting future energy needs: solar energy; energy storage; electric power systems; and carbon capture, utilization, and storage.
“The world will need 50 percent more power in the next 20 years,” says Steve Bolze, president and CEO of GE Power. “GE and MITEI are proud to be working together to find new solutions to develop cleaner, more affordable and accessible energy solutions that will address this need. Together we’ll be able to leverage our collective capabilities, research, and technology solutions to help improve efficiency while reducing the impact of electricity generation on the environment.”
GE will participate in supporting MIT faculty and student research through MITEI. MITEI will bring GE and other members together to connect innovation, business, and policy to transform the energy industry.
MITEI’s relationship with GE will engage and involve all of GE’s energy-related businesses: GE Power, GE Renewable Energy, GE Oil & Gas, GE Energy Connections, GE’s Global Research Center, GE Global Growth & Operations, GE Ventures, and Current, powered by GE. Among the many benefits of the membership, GE will sponsor research programs at MITEI, contribute to MITEI’s Seed Fund to support novel and early-stage energy research proposals, and participate in several conferences and learning opportunities each year.
“GE’s support as a Sustaining Member and engagement in MITEI’s Low-Carbon Energy Centers will be extremely valuable in spurring further technology advancements to address complex energy and climate challenges — areas where GE’s wealth of expertise and history of developing solutions dovetail with MIT’s research,” says Robert Armstrong, director of MITEI. “We are excited to welcome GE and launch this relationship.”
MITEI’s Low-Carbon Energy Centers — announced last fall as a key component of MIT’s Plan for Action on Climate Change — represent a major part of MIT’s commitment to address climate change through engagement with industry, government, and the philanthropic community.
GE moved its global headquarters to Boston last week, moving into an interim space as it works to develop and build a new global headquarters campus to open in Boston’s Fort Point neighborhood in 2018. Today’s announcement continues GE’s investment and engagement in the Boston area. GE selected Boston because of the region’s innovation, talent, and infrastructure, as well as the strong ecosystem of companies, universities, start-ups, and R&D the city hosts. |
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