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Monday, July 24th, 2017
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| 12:00a |
Lessons from pre-industrial climate control Alpha Arsano is standing next to the MIT Chapel’s marble alter, admiring the view through the domed skylight above. Outside, water surrounds the cylindrical red-brick structure like a shallow moat. Inside the chapel, the brick walls ripple like waves. Tiny windows line the walls and face downward so guests can see slivers of the moat. When sunlight reflects off the water at a certain angle, it shines into the chapel and dances onto the walls.
Arsano, who just earned a master’s in architecture studies and will continue in the fall in MIT’s PhD program in building technology, admires the different qualities of many buildings on campus. But none compare, in her mind, to the MIT Chapel. She says she is captivated by the structure’s simplistic beauty and its ability to seamlessly interact with components of the outside world in a spiritual, sustainable, and striking way.
Bringing environmental elements — specifically, natural ventilation — into a built structure is also a key focus of Arsano’s own work. For the past two years, she has been developing a digital design tool for early-stage building projects that can inform architects and engineers about how well a natural ventilation system could work to provide fresh air and cooling to the building they’re planning.
Dispensing with air-conditioners
When a user inputs a building’s location, yearly climate and weather patterns, and some initial parameters such as the building type (residential, commercial, etc.) and materials, Arsano’s program, named “Clima +,” can predict how well the building should function with natural ventilation. For example, using Clima +, planners might find that an apartment complex in Phoenix, Arizona, could sustain its cooling needs for 50 percent of the year with natural ventilation.
Although other tools claim to provide the same predictive information, Arsano and her advisor, Christoph Reinhart, an associate professor of architecture, were skeptical about these claims.
“I found that they were not telling the full story of the predictability of natural ventilation potential,” Arsano says. “There were some missing links. For example, people, machines, computers, and lighting might influence indoor temperatures to be higher than outdoor temperatures.”
Arsano believes Clima + addresses these details and provides a clearer prediction for a building’s maximum natural ventilation potential. She says this method should be useful for architects since it would provide guiding information as the building’s design progresses. Overall, she hopes that Clima + contributes to the rise of sustainable buildings that take advantage of the fresh air around them rather than relying solely on heating and air-conditioning systems. Arsano says sound research has also demonstrated the long-term cost efficiency of implementing sustainable and natural ventilation techniques.
“We are overusing natural resources. Why not be efficient with the climate?” she says. “It is a misconception that building energy-efficient structures is more expensive. In the long-term it is much cheaper.”
Arsano’s focus will remain on natural ventilation as she transitions into her PhD. However, she is thinking about investigating related topics, such as the implications of climate change. Prior to the advancement of mechanical technology in the 1900s, Arsano says natural ventilation was at the core of architecture. She hopes to bring this approach back to the forefront of the practice today.
Before starting her master’s program at MIT, Arsano was a one of seven students from around the world accepted to join the Transsolar Academy in Stuttgart, Germany. Transsolar is a leading climate engineering firm that specializes in green building consultation. For a year, she learned the fundamental concepts of building physics and used digital design tools to develop environmentally responsive design ideas for a wine factory in Italy and a commercial urban corridor in Addis Ababa, Ethiopia.
Arsano says her time in Germany exposed her to the more empirical, scientific side of architecture and its focus on research methodology.
“I really liked how we were working there. I wanted to take it further so I started to look for programs which had similar paths,” she says. “[MIT] was really fascinating because students aren’t just taking courses; they also become part of a research group. I was looking for that.”
Gender parity
Arsano grew up in Addis Ababa. Her childhood was filled with outdoor activities that gave her the opportunity to engage in the city life. She says these experiences helped form her interest in the physical and cultural facets of the city, which she explored during her undergraduate studies in architecture. She also remembers making visits to see family in the more rural parts of Ethiopia, where she was struck by the differences in lifestyle compared to her home city.
“The difference between developed and developing countries is urbanization. You might not find electrical lights in some places or even [piped] water,” she says. “The vernacular houses [built with traditional methods and local materials] are how people live together. Even for me, it was a cultural difference.”
Arsano says living in Germany for a year was a delightful new experience. Participating in a program where half of the fellows were women was also unusual. When she started school at the Ethiopian Institute of Architecture in Addis Ababa, women made up one-fourth of the class of architecture students, she estimates. When visiting construction sites, she noticed that most of the workers and civil engineers on site were men. She believes the gender balance is starting to shift, but she still considers equal opportunity for women to be a critical issue in architecture.
While at MIT, Arsano has volunteered for the Association of Ethiopian Women in Boston and spoken at community events about questioning cultural norms by using lessons from the scientific method.
“If I want to go into construction, by default I might think it’s not for women, but I have to question that. What’s the limitation? Why can’t I be a construction worker? Why can’t I establish a construction company? What are my challenges? I can try this. I can do this. Maybe step by step. The purpose of questioning and investigating will help us get free from those limitations or those limitations that we think are there,” Arsano says.
Arsano’s outreach work in Boston’s Ethiopian community has extended to children’s education as well. At the invitation of a fellow Ethiopian engineer, Sintayehu Dehnie, Arsano and several other MIT students have been participating in a program for children ranging from 4th grade to high school.
“I engage with the community when I get the chance,” says Arsano. “Children ask you the weirdest questions ever. They ask questions you cannot answer. I really like mapping children’s minds.”
Contemplating the chapel
The MIT Chapel is empty except for two other people. One man walks up to a section of the brick-wall where the bricks have been laid so that it appears the wall has Rubik’s cube-sized holes between each brick.
The man, a visiting architect from another country, asks Arsano if she knows whether these holes serve a practical purpose. She isn’t sure. Without knowing Arsano or her work, the man postulates that they might allow fresh air from outside to come through. “Could be,” Arsano replies.
She walks outside to check the other side of the wall for evidence that the pores go all the way through. It appears that they don’t — perhaps a missed opportunity for the MIT Chapel to reap the benefits of natural ventilation. | | 9:00a |
Reshaping computer-aided design Almost every object we use is developed with computer-aided design (CAD). Ironically, while CAD programs are good for creating designs, using them is actually very difficult and time-consuming if you’re trying to improve an existing design to make the most optimal product.
Researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and Columbia University are trying to make the process faster and easier: In a new paper, they’ve developed InstantCAD, a tool that lets designers interactively edit, improve, and optimize CAD models using a more streamlined and intuitive workflow.
InstantCAD integrates seamlessly with existing CAD programs as a plug-in, meaning that designers don’t have to learn new tools to use it.
“From more ergonomic desks to higher-performance cars, this is really about creating better products in less time,” says Department of Electrical Engineering and Computer Science PhD student and lead author Adriana Schulz, who will be presenting the paper at this month’s SIGGRAPH computer-graphics conference in Los Angeles. “We think this could be a real game changer for automakers and other companies that want to be able to test and improve complex designs in a matter of seconds to minutes, instead of hours to days.”
The paper was co-written by Associate Professor Wojciech Matusik, PhD student Jie Xu, and postdoc Bo Zhu of CSAIL, as well as Associate Professor Eitan Grinspun and Assistant Professor Changxi Zheng of Columbia University.
Traditional CAD systems are “parametric,” which means that when engineers design models, they can change properties like shape and size (“parameters”) based on different priorities. For example, when designing a wind turbine you might have to make trade-offs between how much airflow you can get versus how much energy it will generate.
However, it can be difficult to determine the absolute best design for what you want your object to do, because there are many different options for modifying the design. On top of that, the process is time-consuming because changing a single property means having to wait to regenerate the new design, run a simulation, see the result, and then figure out what to do next.
With InstantCAD, the process of improving and optimizing the design can be done in real-time, saving engineers days or weeks. After an object is designed in a commercial CAD program, it is sent to a cloud platform where multiple geometric evaluations and simulations are run at the same time.
With this precomputed data, you can instantly improve and optimize the design in two ways. With “interactive exploration,” a user interface provides real-time feedback on how design changes will affect performance, like how the shape of a plane wing impacts air pressure distribution. With “automatic optimization,” you simply tell the system to give you a design with specific characteristics, like a drone that’s as lightweight as possible while still being able to carry the maximum amount of weight.
The reason it’s hard to optimize an object’s design is because of the massive size of the design space (the number of possible design options).
“It’s too data-intensive to compute every single point, so we have to come up with a way to predict any point in this space from just a small number of sampled data points,” says Schulz. “This is called ‘interpolation,’ and our key technical contribution is a new algorithm we developed to take these samples and estimate points in the space.”
Matusik says InstantCAD could be particularly helpful for more intricate designs for objects like cars, planes, and robots, particularly for industries like car manufacturing that care a lot about squeezing every little bit of performance out of a product.
“Our system doesn’t just save you time for changing designs, but has the potential to dramatically improve the quality of the products themselves,” says Matusik. “The more complex your design gets, the more important this kind of a tool can be.”
Because of the system’s productivity boosts and CAD integration, Schulz is confident that it will have immediate applications for industry. Down the line, she hopes that InstantCAD can also help lower the barrier for entry for casual users.
"In a world where 3-D printing and industrial robotics are making manufacturing more accessible, we need systems that make the actual design process more accessible, too,” Schulz says. “With systems like this that make it easier to customize objects to meet your specific needs, we hope to be paving the way to a new age of personal manufacturing and DIY design.”
The project was supported by the National Science Foundation. | | 11:00a |
Study: Indian monsoons have strengthened over past 15 years An MIT study published today in Nature Climate Change finds that the Indian summer monsoons, which bring rainfall to the country each year between June and September, have strengthened in the last 15 years over north central India.
This heightened monsoon activity has reversed a 50-year drying period during which the monsoon season brought relatively little rain to northern and central India. Since 2002, the researchers have found, this drying trend has given way to a much wetter pattern, with stronger monsoons supplying much-needed rain, along with powerful, damaging floods, to the populous north central region of India.
A shift in India’s land and sea temperatures may partially explain this increase in monsoon rainfall. The researchers note that starting in 2002, nearly the entire Indian subcontinent has experienced very strong warming, reaching between 0.1 and 1 degree Celsius per year. Meanwhile, a rise in temperatures over the Indian Ocean has slowed significantly.
Chien Wang, a senior research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences, the Center for Global Change Science, and the Joint Program for the Science and Policy of Global Change, says this sharp gradient in temperatures — high over land, and low over surrounding waters — is a perfect recipe for whipping up stronger monsoons.
“Climatologically, India went through a sudden, drastic warming, while the Indian Ocean, which used to be warm, all of a sudden slowed its warming,” Wang says. “This may have been from a combination of natural variability and anthropogenic influences, and we’re still trying to get to the bottom of the physical processes that caused this reversal.”
Wang’s co-author is Qinjian Jin, a postdoc in the Joint Program for the Science and Policy of Global Change.
A theory drying up
The Indian monsoon phenomenon is the longest recorded monsoon system in meteorology. Measurements of its rainfall date back to the late 18th century, when British colonists established the country’s first weather observatories to record the seasonal phenomenon. Since then, the Indian government has set up several thousand rain gauges across the country to record precipitation levels during the monsoon season, which can bring little or no rain to some areas while deluging other parts of the country.
From these yearly measurements, scientists had observed that, since the 1950s, the Indian monsoons were bringing less rain to north central India — a drying period that didn’t seem to let up, compared to a similar monsoon system over Africa and East Asia, which appeared to reverse its drying trend in the 1980s.
“There’s this idea in people’s minds that India is going to dry up,” Wang says. “The Indian monsoon season is undergoing a longer drying than all other systems, and this created a hypothesis that, since India is heavily polluted by manmade aerosols and is also heavily deforested, these may be factors that cause this drying. Modeling studies also projected that this drying would continue to this century.”
A persistent revival
However, Wang and Jin found that India has already begun to reverse its dry spell. The team tracked India’s average daily monsoon rainfall from 1950 to the present day, using six global precipitation datasets, each of which aggregate measurements from the thousands of rain gauges in India, as well as measurements of rainfall and temperature from satellites monitoring land and sea surfaces.
Between 1950 and 2002, they found that north central India experienced a decrease in daily rainfall average, of 0.18 millimeters per decade, during the monsoon season. To their surprise, they discovered that since 2002, precipitation in the region has revived, increasing daily rainfall average by 1.34 millimeters per decade.
“The Indian monsoon is considered a textbook, clearly defined phenomenon, and we think we know a lot about it, but we don’t,” Wang says. “Here, we identify a phenomenon that was mostly overlooked.”
The researchers did note a brief drying period during the 2015 monsoon season that caused widespread droughts throughout the subcontinent. They attribute this blip in the trend to a severe El Niño season, where ocean temperatures temporarily rise, causing a shift in atmospheric circulation, leading to decreased rainfall in India and elsewhere.
“But even counting that dry year, the long-term [wetting] trend is still pretty steady,” Wang says.
More questions ahead
The team believes the current strong monsoon trend is a result of higher land temperatures in combination with lower ocean temperatures. While it’s unclear what is causing India to heat up while its oceans cool down, the researchers have some guesses.
For example, Wang says ocean cooling could be a result of the natural ebb and flow of long-term sea temperatures. India’s land warming on the other hand, could trace back to reduced cloud cover, particularly at low altitudes. Normally, clouds act to reflect incoming sunlight. But Wang and others have observed that in recent years, India has experienced a reduction in low clouds, perhaps in response to an increase in anthropogenic aerosols such as black carbon or soot, which can simultaneously absorb and heat the surrounding air, and prevent clouds from forming.
“But these aerosols have been around even during the drying period, so there must be something else at work,” Wang says. “This raises a lot more questions than answers, and that’s why we’re so excited to figure this out.”
This research was supported, in part, by the National Science Foundation, the National Research Foundation of Singapore, and the Singapore-MIT Alliance for Research and Technology (SMART) center. | | 11:40a |
Laying the foundation for new energy technology Troy Van Voorhis remembers being jolted by the announcement in 1989, when he was in the seventh grade, that researchers had successfully demonstrated cold fusion.
“My science teacher canceled our regular class to explain this remarkable development,” recalls Van Voorhis, the Haslam and Dewey Professor of Chemistry at MIT. “The idea really captured my imagination, and I was hooked on the possibility that you could produce energy from the physical reactions of chemicals.”
Although the apparent breakthrough quickly proved to be spurious science, it ignited Van Voorhis’ lifelong interest in energy and chemistry. Nearly three decades later, the theoretical chemist investigates what he calls “energy-related big questions.” He scrutinizes and models the behavior of electrons in research that, among other things, seeks to improve the photovoltaic cells used in solar energy; to develop new, high-efficiency indoor lighting; and to create chemical storage technology for electricity generated by renewable energy technologies.
While his fuse for scientific discovery was lit early on, it took time for Van Voorhis to find his niche exploring the intricate dynamics of molecules involved in processes that produce, transfer, and store chemical energy.
Raised in the Northside section of Indianapolis by a father who taught junior high school mathematics and a mother who was a professor of social work, Van Voorhis was, in his own words, a “shy, introverted child.” In high school, he found theater a constructive way to break out of his shell. “Interacting with an audience was easier than interacting with individuals,” he says.
Van Voorhis also spent a lot of time “playing with mathematics problems because it was something you could do on your own.” But he worried about pursuing the subject as a college major because, he says, “it seemed too abstract.” Instead, he decided to pair math with chemistry, another area he excelled in during high school.
In college, as he describes it, Van Voorhis pursued “curiosity-based science,” first at Rice University, where he earned his BA as a double major in 1997, and then at the University of California at Berkeley, where he conducted his graduate studies in chemistry. One area that captured his imagination involved finding better ways to describe mathematically how chemical bonds rupture. “It was a question I thought sounded interesting, a difficult problem,” he says. “But it was not something that proved to be useful to other people.”
Pairing up
It was not until Van Voorhis landed at MIT, he says, that he understood that his technical tools “might actually solve really important problems.” He credits a formative encounter in his early days as an assistant professor with bringing about this revelation.
“I sat down to lunch with the late, great theoretical chemist [and former dean of the School of Science] Robert Silbey and told him I was stuck on a direction to take as I started out,” Van Voorhis recalls. “He told me to talk to experimentalists at MIT, who were working on the most exciting problems, ask them how I could help them, and then hitch myself to their wagons.”
Wasting no time, Van Voorhis found an eager experimentalist partner in Marc Baldo, who is now a professor of electrical engineering and computer science. Baldo, who had also recently arrived at MIT, was looking into the application and potential benefits of organic chemicals in light-emitting diodes (LEDs) and solar cells. “I told him my lab worked on simulations involving electrons and chemical bonds and maybe we could help him,” says Van Voorhis. “It was the start of a beautiful friendship.”
It also launched a fruitful research collaboration. In their very first project together, Van Voorhis provided the computational firepower to help Baldo demonstrate that subtle manipulations of energy states in organic LEDs could improve efficiency in light output. The technical skills that Van Voorhis brought to MIT had found a novel and practical outlet.
Starting in 2005, Van Voorhis and Baldo began focusing on ways to push past longstanding limits in a range of energy technologies, starting with solar power from photovoltaic (PV) cells.
Since the first silicon solar PV panels were invented in the 1960s, they have managed to achieve at best 25 percent efficiency as they absorb photons from the sun and convert that energy into electrical current.
Van Voorhis and Baldo demonstrated that it was possible to overcome this limit. Normally, a single photon yields one electron plus waste heat. But by lining solar cells with organic molecules, they figured out how to take a photon and produce two electrons, generating twice as much electricity and less waste heat.
“Marc and I theoretically proved it might be possible to use fission in a device to make a solar cell more than 100 percent efficient,” says Van Voorhis.
Catalyzing brighter solutions
In other domains of research, Van Voorhis and Baldo are testing organic dyes that could help make organic LEDs brighter and perhaps as long-lasting as current conventional LEDs — up to 100,000 hours.
They are also actively investigating chemical-based energy storage in the hopes of helping to bring renewable energy sources such as solar to scale. “The energy content of a normal gas-powered car battery, which weighs 25 pounds, is the same as a quarter-pound Big Mac,” Van Voorhis says. “There’s a huge incentive to convert electricity into chemical fuels that are energy-dense, but we need to find the right abundant and cheap catalyst for making chemical conversions possible.”
One catalyst candidate, a super-thin sheet of graphitic carbon, doped with elements such as nitrogen, boron, or sulfur, presents intriguing possibilities as the basis for a new type of fuel cell. Van Voorhis is now running high-throughput computational simulations to figure out the best kind of molecules to pair with graphite for the optimal electrochemical conversion cocktail.
For these research endeavors, Van Voorhis draws inspiration not only from faculty colleagues but also from students. In his primary teaching assignment, the introductory class 5.111 (Principles of Chemical Science), Van Voorhis says he incorporates “bits from my research on photovoltaics and alternative fuels, helping students make connections and see the relevance of these ideas.”
“My greatest pleasure in teaching is seeing the lightbulb go on for students — that instant where a topic goes from a complete mystery to something that is just starting to make sense,” he says.
Van Voorhis views mentoring graduate students as a lifelong relationship.
“My job as an advisor is to help them become independent scientists, and I find that exposing them to problems of long-range societal relevance like energy or the environment is crucial to them developing into responsible, mature researchers who will be able to devote their skills to problems of significance,” he says.
He says he is also heartened to see so many among his MIT students who are “socially conscious and motivated to work on energy questions,” including in his own laboratory. He finds this engagement reassuring, given that many of the challenges he works on in energy technology may take years to solve.
“With problems this big, I have to be comfortable being a cog in a very large machine, where I do the part I’m good at and rely on someone else to do their part, and together we solve the problem.”
This article appears in the Spring 2017 issue of Energy Futures, the magazine of the MIT Energy Initiative. |
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