By Denise Brehm
Civil and Environmental Engineering

Emphasizing the need to think outside disciplinary boundaries in research and education, to build and invent, and to foster an entrepreneurial spirit among students and faculty, Professor Markus Buehler, head of the Department of Civil and Environmental Engineering (CEE), laid out his vision for the department in a presentation to alumni at the first CEE New Research Breakfast held Oct. 17 in the Bush Room.

Buehler — who in his own research draws on natural systems and hierarchical materials like bone to understand and design stronger, lighter human-made materials — compared the urban environment to a glial cell. Referring to slides of a cell and an aerial photo of a lighted city, he pointed out a likeness between the appearance of the two and similarities in their networks for messaging, moving materials and other functions. Glial cells, which form a structure to support neurons, also supply them with nutrients and protect them from pathogens, much as the city’s transportation, information and infrastructure systems serve its inhabitants.

Understanding and modeling urban environments as systems is one of the world’s ongoing major challenges, he said, and one in which CEE researchers are taking the lead by “building quantitative models of cities to improve the health of both infrastructure and the environment, and modeling human behavior as well as influencing it,” he said. “Studying natural systems can help us do this better.”

Four other CEE faculty gave short presentations at the breakfast, which was organized by development officer Paul Hohenberger as an annual event for alumni in the Northeast to gather in October, hear a State of the Department address, and learn about ongoing and new interdisciplinary research and educational programs.

“We’ve entered a new era with a renewed focus on students and education that emphasizes the entrepreneurial spirit: going out into the world and creating things,” Buehler said in his address. “These inspiring faculty presentations provide a snapshot of the exciting research and educational work done in CEE. The cutting-edge research provides great opportunities for our undergraduate and graduate students — in classroom and laboratory education and research projects.”

How Air Pollution and Climate Impact Global Food Security

Associate Professor Colette Heald of CEE and the Department of Earth, Atmospheric and Planetary Sciences, spoke about the need to understand how particles and gases in the atmosphere evolve physically and chemically and what effects they have on human health, climate and crops.

“There are no international boundaries in the atmosphere,” Heald said. Climate change and ozone pollution are expected to have a major regional effect by 2050, when climate change could cause a 20-40 percent decrease in maize crop yields, and ozone pollution a similar but lesser impact on wheat crops. These changes could contribute to increased undernourishment in developing countries, she said.

Heald’s research interests are global atmospheric composition and chemistry and the interactions of these with the biosphere and climate system. She teaches the senior capstone course, 1.S992/1.013 Senior Civil and Environmental Engineering Design, with Associate Professor Jesse Kroll of CEE and chemical engineering.

This year, undergraduates in the class are designing a method for assessing the exposure of the MIT community to airborne pollution via a sensor network that would create a “smart campus.” The class is using the new collaborative Lincoln Labs-MIT space in Technology Square known as Beaver Works, and Lincoln Lab mentors are working with students on designs and prototypes.

Smorphs, new class of materials, turn mechanical failure into functionality

Pedro Reis, the Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering and Mechanical Engineering, studies the mechanics of slender structures, with a particular focus on devising new ways of turning mechanical failure into functionality.

He described a new class of materials he developed called “smorphs,” smart morphable surfaces designed to provide complex surface topography on demand. An example of a natural smorph is the prune (a dehydrated plum), which wrinkles during dehydration. The morphology of many dried fruits like prunes, Reis said, is similar to the surface of golf balls, which have dimples to enhance their aerodynamic performance.

After giving a brief, entertaining history of golf balls that explained how they acquired dimples, Reis said that buckling patterns can be induced in smooth shells in a controlled, reversible manner by manipulating internal pressure.

Possible applications for this work include radomes (domed structures that protect radars), whose structural failure might be prevented by coating them with a smorph. Other “pie-in-the-sky” examples include coating airplane wings with smorphs to improve their aerodynamics, and designing a dimpled automobile for better fuel efficiency, Reis said.

Reis, who was named to Popular Science’s 2013 Brilliant 10 List, teaches the sophomore design course, 1.101 Introduction to Civil and Environmental Engineering Design, in which students design, prototype and fabricate their own projects from concept to implementation. The course also introduces students to digital fabrication tools including 3-D printing and laser cutting in a dedicated rapid prototyping laboratory that CEE recently set up exclusively for educational projects.

Mining cellphone data to improve urban livability

In 2013, 50 percent of the world’s population lives in cities; by 2020, 70 percent will live in cities, said Marta González, the Gilbert Winslow Career Development Assistant Professor. “How can we quantify the needs of people living in cities to improve life?” she said, referring to transportation and energy networks and population distribution.

“We now have 2 billion Internet users, but 6 billion cellphone users,” she said. “U.S. users spend one hour a day accessing the Internet on their cellphones. Cellphones are the neurons of a truly global nervous system of the global communications network.”

González uses tools like statistical physics applied to anonymous cellphone data to infer the locations visited by users and learn “how people are behaving in space and time.” This led her to discover some underlying universal patterns of human mobility that may allow transportation engineers to design improved strategies for reducing traffic congestion.

González has also studied the growth of Twitter in its formative days and, working with CEE Associate Professor Ruben Juanes, ranked U.S. airports in terms of their ability to spread epidemics.

She’s now working with cellphone data to group users by types of locations visited, then explore their social networks, work she hopes will lead to the creation and use of feedback loops between users and planners and, eventually, to online platforms to motivate public participation in day-to-day and even hour-to-hour decision-making about urban transportation networks. She describes the feedback loops and online platforms as “social network game changers.”

Her work on universal human mobility patterns is currently being tested in transportation systems and logistics planning in Rio de Janeiro, as that city prepares to host the 2014 World Soccer Cup.

Benign design of materials now can avoid problems in the future

Philip Gschwend, the Ford Professor of Civil and Environmental Engineering and director of CEE’s Ralph M. Parsons Laboratory for Environmental Science and Engineering, described the “legacy of problems buried in our environment” that often arise as side effects of products designed to solve other problems.

One example he cited is PCBs, which were used as nonflammable dielectric and hydraulic fluids. Although their production was banned decades ago, PCBs are still widespread in the environment, including in the Hudson River. And in order to clean up such contamination now, the Hudson is being dredged and the contaminated sediment shipped away at a cost of almost a billion dollars.

But it might not work, Gschwend said, because moving most of the PCB-contaminated sediment likely leaves behind additional material that will act like “time-released doses.” This case, he said, is similar to what happened with DDT from World War II use. Officials in the San Francisco Bay area had sediment removed from a particularly contaminated location in the bay in the late 1990s. DDT levels initially went down in shellfish. But 10 years later, DDT levels in shellfish rose again to pre-dredging levels.

Likewise, catalytic converters, he said, were a great means of lowering air pollution, but because of their use, platinum levels in the environment went up, as shown by Professor Harry Hemond’s group.

“And Scotchgard on our furniture? In principle it’s great,” said Gschwend. “But the material we were told is glued to the upholstery is now found in the bodies of polar bears,” according to published research, he said.

To understand current issues like these, the Gschwend group has developed inexpensive sheets of polyethylene that can be placed in mud or water to soak up chemicals and measure those contaminant’s availability as they move in the environment causing organism exposure. The goal is to examine pollution from the past to learn what processes control chemical doses in various environments.

But the real answer, Gschwend said, is to prevent such problems in the first place by changing the process of materials and chemicals design to involve environmental chemists at the outset.

“We need to be standing next to our colleagues … work with them to anticipate what could be the downside environmentally to what they’re doing, and ask if we can make small changes in that the product’s chemical or material structure to prevent, or at least greatly reduce, environmental damages from the beginning,” he said.

Applying tools like nanotechnology, urban physics and environmental microbiology to these and other areas — such as materials design, oceans, alternative energy grids and resources, biomes and ecosystems, the health of the planet and coastal processes — allow CEE researchers to see that all things are connected, said Buehler. “This approach forms the fabric of CEE at MIT,” he said.