Why Cement is the Most Important Man-Made Material on Earth...

Robots the size of a human blood cell could monitor everything from human bodies to oil pipelines. But first they've got to get built. A team from MIT has developed a new model for building microscopic robots, a system they're calling "autoperforation." The system uses a type of carbon called graphene, a super strong material that contains a single layer of atoms. Graphene is heavily hyped these days, but the MIT researchers were able to exploit an unusual quality: Its brittle nature. Like a wafer or an egg, graphene can shatter easily. "We discovered that you can use the brittleness," says MIT Professor Michael Strano in a press statement. "It's counterintuitive. Before this work, if you told me you could fracture a material to control its shape at the nanoscale, I would have been incredulous." It works like this: A layer of graphene is placed over an array of polymer dots, tiny semiconductors. As the graphene drapes over the round edges of the dots, lines of strain begin to emerge. "Imagine a tablecloth falling slowly down onto the surface of a circular table," says grad student Albert Liu, who worked with Strano on the project. "One can very easily visualize the developing circular strain toward the table edges, and that's very much analogous to what happens when a flat sheet of graphene folds around these printed polymer pillars."...

In times of limited resources and continued evidence of significant climate change, sustainability is increasingly regarded as a topic of global importance. Consider areas such as design, energy, and materials: These core concepts associated with sustainability are part of an integrative spectrum of widespread innovation. “Sustainability is a fashion nowadays,” says Oral Buyukozturk, professor of civil and environmental engineering (CEE) at MIT. “But the concept is often used so loosely that many people are unsure of what it really means.” With a particular focus on mechanics, the durability of construction materials, and sound design, Buyukozturk has catalyzed several multidisciplinary ventures in CEE — all with the goal of advancing the science and engineering of quantifiably sustainable designs for infrastructure. “Physical and civil infrastructures inevitably deteriorate over time,” Buyukozturk says. “Construction material deterioration is a global problem, and we are faced with two challenges: How do we rehabilitate and repair existing structures, and how do we build new systems that are more durable under today’s conditions?” His work in the sustainability of the built environment strives to provide solutions....