Remembering Professor Emeritus Stephen Crandall
Stephen H. Crandall, the Ford Professor of Engineering Emeritus at MIT, a pioneer in random vibrations and rotordynamics, and a leader in transforming mechanics into an engineering science, passed away Oct. 29, in Needham, Mass. He was 92 years old.
After earning his PhD in mathematics from MIT in 1946, Crandall transferred to the Department of Mechanical Engineering. There, he was appointed to assistant professor of mechanical engineering in 1947, associate professor in 1951, then to professor in 1958. He was named Ford Professor of Engineering in 1975, and an emeritus professor in 1991. While at MIT, Crandall led the transformation of mechanics into an engineering science, acting as editor of three groundbreaking texts: “Random Vibrations” (1958), “An Introduction to the Mechanics of Solids” (1959), and “Dynamics of Mechanical and Electromechanical Systems” (1968). Crandall was a pioneer of random vibrations research, offering the first academic course on the subject in 1958, and subsequently directing MIT’s Acoustics and Vibration Laboratory for 33 years. He published a total of eight books and 160 technical papers.
Crandall’s professional contributions have been widely recognized. He was elected to the American Academy of Arts and Sciences, the National Academy of Sciences, the National Academy of Engineering, and the Russian Academy of Engineering. The Acoustical Society of America awarded him the Trent-Crede Medal in 1978, and the American Society of Civil Engineers awarded him both the Theodore von Karman Medal, in 1984, and the Freudenthal Medal, in 1996. ASME awarded Crandall the Worcester Reed Warner Medal in 1971; the Timoshenko Medal in 1990; the Den Hartog Award in 1991; and the Thomas K. Caughey Dynamics Award in 2009. He was inducted as an honorary ASME member in 1988.
Beaver Works Center for Project-Based Collaboration
The Lincoln Lab Beaver Works Center – a newly renovated, 5,000 square-foot facility comprised of multiple research areas, classrooms, and a prototyping lab – opened this fall to support project-based research and education in the School of Engineering. The facility is ideally suited for students in MechE taking hands-on courses, pursuing UROP research, or performing graduate activities that overlap MIT Lincoln Laboratory, a joint partner in the venture with broad interests in advanced systems and technology.
The center is located at 300 Technology Square in Kendall Square, on the edge of the MIT campus. It offers students flexible space, with an abundance of tools for building and prototyping, including standard wood/machine shop tools, 3D printers, laser cutters, and heavy machine tools, as well as modular work benches that can wheel in and out of rooms as needed.
Several Beaver Works projects – many of which are major elements of capstone courses – have already been completed, such as self-deployed RC aircrafts designed and built by students in Course 2.007 and unmanned underwater vehicle (UUV) propulsion systems, designed and prototyped in Professor Doug Hart’s year-long 2.013/4 sequence.
“About three years ago we challenged Professor Doug Hart and students in MechE to develop an energy source for underwater systems that increases endurance by tenfold. The result is a novel method that exploits the energy released when aluminum reacts with water,” says Nicholas Pulsone, a senior staff member of Lincoln Laboratory (LL) and LL advisor to Hart’s 2.013/4.
“The Beaverworks Center is the perfect environment for bringing together students and faculty from MIT along with engineers from Lincoln Laboratory and Woods Hole Oceanographic Institution to work on this type of exciting project.”
From Grabbing Water to Cleansing Palates – Professor Pedro Reis
Professor Pedro Reis’s team has developed a floral pipette based on the behavior of certain water lilies, which float at the surface of ponds or lakes while anchored to the floor. As water rises, hydrostatic forces act to close a lily’s petals, preventing water from flooding in. Taking the water lily as inspiration, Professor Reis designed an upside-down flower that does the opposite, grabbing water as it’s pulled up, thereby reversing the role of gravity. Reis and John Bush, professor of applied mathematics at MIT, calculated the optimal petal size for capturing a small sip of liquid, such as a palate cleanser, then used a 3-D printer to form molds of the flower, each of which is about 35 millimeters wide — about the size of a small dandelion. “By pulling this out of liquid, you get something that seals shut and looks like a cherry. Touch it to your lips, and it releases its fluid,” Bush says. The pipette is now being used by renowned Spanish chef Jose Andres. -Jennifer Chu, MIT News Office
Anklebot – Professor Neville Hogan
The ankle — the crucial juncture between the leg and the foot — is an anatomical jumble, and its role in maintaining stability and motion has not been well characterized. Professor Neville Hogan and his colleagues in the Newman Laboratory for Biomechanics and Human Rehabilitation have developed a way to measure the stiffness of the ankle in various directions using a robot called the “Anklebot.” The robot is mounted to a knee brace and connected to a custom-designed shoe. As a person moves his ankle, the robot moves the foot along a programmed trajectory, in different directions within the ankle’s normal range of motion. Recording the angular displacement and torque at the joint, researchers calculate the ankle’s stiffness. From their experiments with healthy volunteers, the researchers found that the ankle is strongest when moving up and down, as if pressing on a gas pedal. The joint is weaker when tilting from side to side, and weakest when turning inward. The findings, Hogan notes, may help clinicians and therapists better understand the physical limitations caused by strokes and other motor disorders. -Jennifer Chu, MIT News Office
Mission TULip – Professor Franz Hover
Professor Franz Hover and graduate student Brooks Reed have demonstrated a multi-vehicle marine robotic system to track and pursue agile underwater targets such as sharks. The vehicles measure range to the target and collaborate to jointly estimate the target’s position and drive to stay in formation relative to it. For wireless underwater communication, acoustics are the only technology suitable for distances more than 100 meters, but they suffer from extremely low bit rates and frequent packet loss. Despite these severe communication constraints, Hover and Reed’s experimental results demonstrate that aggressive dynamic tracking and pursuit is possible underwater, and they quantify some of the tradeoffs involved in designing such a system. They also hope to extend these methods to include the tracking of dynamic ocean features like a flowing oil spill or temperature front, utilizing similar communication and control techniques and additionally leveraging ocean model forecasts.
Good and Bad Bacteria – Professor Cullen Buie
There are good bacteria and there are bad bacteria — and sometimes both coexist within the same species. However, determining whether a bacterium is harmful typically requires growing cultures from samples of saliva or blood — a time-intensive laboratory procedure. Professor Cullen Buie and his research group have developed a new microfluidic device that could speed the monitoring of bacterial infections associated with cystic fibrosis and other diseases. The new microfluidic chip is etched with tiny channels, each resembling an elongated hourglass with a pinched midsection. Researchers injected bacteria through one end of each channel and observed how cells travel from one end to the other. From their experiments, the researchers found that their device is able to distinguish benign cells from those that are better able to form biofilms. -Jennifer Chu, MIT News Office