January
2005
Hari Dharan holds one of the prototype booms. The machine beside him is used to push the molding form out from the center of the rolled carbon fiber tube. (David Pescovitz photo) |
In his robotics laboratory at UC Berkeley, engineering professor Ron Fearing is taking an engineering cue from the feet of geckos to develop new dry adhesives for future wall-climbing and surgical robots. Across campus, physicist Carlos Bustamante is exploring whether the energy in a tightly-wound DNA molecule could drive a motor that's 300 times smaller than the diameter of a human hair. Back in the College of Engineering , Arun Majumdar is devising a biosensor chip laden with tiny cantilevers that flex like diving boards when minute molecules indicative of cancer or other diseases bind to them. These efforts are just a sampling of the research projects that will be accelerated by UC Berkeley's new $11.9 million Center of Integrated Nanomechanical Systems (COINS), launching this fall.
An animated series of scanning electron microscope pictures of the spinning rotor of a nanomotor fabricated in the lab of UC Berkeley physicist Alex Zettl. The entire electric motor is about 500 nanometers across, 300 times smaller than the diameter of a human hair. (courtesy the researchers) |
The cross-disciplinary center aims to develop a storehouse of mechanical components--from motors to batteries to transistors. These building blocks could then be combined into machines that leverage the unique characteristics that emerge at the nanoscale. (A nanometer is one-billionth of a meter.) In many cases, the devices could be batch produced en masse using methods similar to those used to manufacture integrated circuits.
"We'll be designing new and modifying existing building blocks to make them accessible to assembling technologies to the point where you could order them like you order lumber at a lumberyard," says center director Alex Zettl, a UC Berkeley professor of physics and an internationally-recognized leader in nanoscience.
COINS is one of six Nanoscale Science and Engineering Centers across the country funded by the National Science Foundation. Consisting of researchers from UC Merced, Stanford University , and the California Institute of Technology, the Berkeley-based center is unique in that its specific focus is on mechanics at the nanoscale. The COINS work will take advantage of several state-of-the-art nanoscale "machine shops" now under construction, including Lawrence Berkeley National Laboratory's Molecular Foundry at Lawrence Berkeley National Laboratory, the Nanofabrication Facility in the new headquarters of the Center for Information Technology Research in the Interest of Society (CITRIS), and the Biomolecular Nanotechnology Center at Stanley Hall, future home to the Department of Bioengineering and the California Institute of Quantitative Biomedical Research (QB3).
The nano-electromechanical devices and systems (NEMS) that emerge from these laboratories will present scientists and engineers with novel methods for manipulating matter, both artificial and biological. Indeed, the new nanomechanical "tinkertoys" could help bridge the gap between nature's own nanotechhnology and devices constructed in a laboratory.
Ron Fearing and his colleagues fabricated dense patches of synthetic gecko hair with adhesive properties by casting polyurethane in an array of nanopores. |
"Efforts to combine biological and synthetic systems could lead to highly-effective chemical and biological sensors," says Tom Kalil, Special Assistant to the Chancellor for Science and Technology. "Eventually, nanomechanical miniaturization will also revolutionize technologies for computation, communication, and power generation."
For example, Majumdar and Ramamoorthy Ramesh, who holds a joint position in Materials Science and Engineering and the Department of Physics, are constructing nanoscale plumbing systems that pump the most minute measurements of fluid. Their basic research may be the foundation for nanofluidic batteries, or even transistors that manipulates the flow of biological molecules instead of electricity. Meanwhile, mechanical engineer Lydia Sohn is developing an artificial nanopore for disease detection that mimics the filtration system of human cells.
According to Kalil, who helped spearhead the establishment of COINS, UC Berkeley is already primed to advance the NEMS revolution. Two decades ago, he explains, the Berkeley Sensor and Actuator Sensor pioneered the development of micro-electromechanical systems (MEMS). These teensy machines, no bigger than the period at the end of this sentence, are found in everything from automobile airbags to the wireless networks of Smart Dust sensors now making headlines.
Berkeley MEMS pioneers and COINS researchers Tsu-Jae King, Roger Howe, and Jeffrey Bokor are hoping to continue their silicon scaling success by building low-power mechanical resonators out of nanowires for wireless communications applications. They're also proposing NEMS transistors to meet the low-cost, low-power, high-density computation and memory needs of tomorrow's mobile electronics.
"In many respects, Berkeley is the birthplace of micro-electromechanical systems," Kalil says. "So this is a logical place to lead the shift from the microscale to the nanoscale."
Flirting with Disasters
by David Pescovitz
Professor Robert Bea is also an expert on ocean environmental forces that can have a dramatic impact on undersea oil and natural gas resources. |
In 1988, Robert Bea was preparing to bring four decades of ocean engineering experience to UC Berkeley as a newly hired professor of Civil and Environmental Engineering. Then something unexpected happened. The Piper Alpha oil production platform in the North Sea exploded, killing 167 people and causing $4 billion in damage. Bea was called in to help determine the cause of the accident. The trail he uncovered led him down a long research path where engineering, business management, and the social sciences intersect.
"It became clear to me that the problem was not technology, but people," he says. "Worker safety is well established. But when you bring people together as operating teams or even corporations, a new set of problems begins to emerge."
In the case of the Piper Alpha, Bea explains, the explosion and resulting fire was sparked by "normalization of deviance." Early warning signs of danger had been normalized over the years in the sense that they no longer raised red flags to operators. On July 6, a gas leak in a pump caused an explosion that started a domino effect of fiery devastation. But why were so many lives lost? How did the evacuation go so wrong? According to Bea, "It was a chain of important errors made by people in critical situations involving complex technological and organization systems." That theme, he says, reared its ugly head over and over as he went on to investigate accidents as seemingly diverse as the Exxon Valdez oil spill and the Space Shuttle Columbia catastrophe.
The Piper Alpha oil platform burned on July 6, 1988, killing 167 people. |
By the time Bea began working with NASA, the Space Agency's approach to human and organizational factors had already been called into question. On January 28, 1986 , the Space Shuttle Challenger exploded shortly after liftoff. The explosion was caused by the failure of an "O" ring seal in a rocket booster. It was revealed that NASA was informed before launch that the performance of the O-rings could be compromised by the cold weather. Still, the decision was made not to delay the mission. Put simply, Bea says, there was a communication breakdown enabled by a counterproductive management philosophy. While a piece of broken foam insulation rather than a cracked O ring brought down the Space Shuttle Columbia last year, NASA's risk-assessment and decision-making process was once again scrutinized.
"We look back now and say these accidents could have been prevented," Bea says. "NASA had delivered incredibly high levels of individual performance, but they struggled with groups."
To suss out the kinks in complex organizations, Bea collaborates with Karlene Roberts, a professor in Organizational Behavior and Industrial Relations at the UC Berkeley Haas School of Business. By analyzing organizational catastrophes, and triumphs, from both an engineering and a human perspective, the researchers hope to develop risk assessment and management approaches that can reduce the impact of accidents when they do occur.
Their methods to enhance reliability in complex organizations may seem intuitive, but they often go against the grain of large corporate or institutional structures. For example, Bea and Roberts posit that organizations should "balance efficiency with reliability." Individuals should be rewarded for safe operational practices even if direct orders suggest that safety should be ignored even momentarily.
"When organizations focus on today's profits without consideration of tomorrow's problems, the likelihood of accidents increases," the researchers wrote in a journal paper entitled "Must Accidents Happen? Lessons from high-reliability organizations."
Another of the researchers' tenants is that large organizations must keep communication channels open and encourage information to flow. Take disaster-response teams that fight massive forest fires, Bea says. To succeed, hundreds of people and thousands of tons of equipment must be appropriately routed by numerous agencies from perhaps dozens of geographical regions. Coordination is the key to saving lives.
"They do this by defining and communicating a common big picture and by quickly establishing a command and control system that fits all the participants into a common goal with a common reporting structure," they wrote.
Accidents will happen, Bea admits. In fact, he points out that the History Channel has dedicated an entire series of television programs to "Engineering Disasters," from a subway tunnel cave-in to the Challenger accident. But every sad tale contains lessons to be learned.
"If you watch a few of the episodes, you'll quickly see the theme of my research emerge," he says. "Organizations need to be engineered at a level appropriate for the complexity of the technology surrounding them."
Ka-Ngo Leung (second from right) with Ye Chen, Lili-Ji, and Qing Ji beside their test apparatus. (Berkeley Lab photo) |
UC Berkeley nuclear engineer Ka-Ngo Leung has developed a highly-efficient ion beam technology that could edge out tried-and-true methods for fabricating myriad microscale products. Medical implants that are currently manufactured one at a time could be batch produced in bulk. The new ion beam technology could also boost production at microchip fabrication facilities while helping keep Moore's Law on track, says Leung, the head of the Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory.
Ion beams that deliver a steady stream of positively-charged particles are already common tools in the semiconductor industry. Engineers use the focused energy to add impurities that change a semiconductor's electrical properties, characterize the material, and pattern structures on it just nanometers in size. (A nanometer is one-billionth of a meter.)
The problem, Leung explains, is that when the ion beam hits a non-conductive material, for example a silicon wafer's insulating substrate, that material becomes charged by the positive ions. As the charge accumulates, it repels the ions and causes the beam to lose its pinpoint focus.
A double-chamber plasma source forms beams of positive ions and electrons that can simultaneously be delivered to a target. (Berkeley Lab photo) |
"This becomes an increasingly serious problem when you're talking about shrinking the features on the circuit to even smaller length-scales," says Leung, a professor-in-residence in the Department of Nuclear Engineering. . "The charge can also jump from one point to another on the sample, perhaps damaging the circuit."
Collaborating with his graduate students and Qing Ji, a guest researcher at the Berkeley Lab, Leung designed a system that adds a flood of electrons to the ion beam. The negatively-charged electrons neutralize the ions, preventing the sample from building up a problematic charge. Balancing out the ion beam with an electron beam is common practice, Leung points out, but combining the two into a single beam is entirely novel.
Integrating the two beams was a necessity for the researchers' ion beam imprinter, a system that enables hundreds or thousands of ion beams to be generated using a single ion source. With so many ion beams, Leung explains, it would be virtually impossibly to align each one with a separate electron beam.
According to Leung, the combined electron and ion beam can remove several steps from traditional lithographic techniques used to fabricate integrate circuits. During the fabrication process, ions, known as dopants, are implanted in the silicon wafer to change way electricity is conducted. In order to implant ions in some specific regions of the wafer and not others, a mask, or stencil, is applied to the wafer to protect the regions that shouldn't be hit with the beam. The ion imprinter negates the need for the wafer masking process by putting the mask at the source of the beam. The technique is not unlike making hand-shadows on a wall with a flashlight.
"The ion beams are coming right out of the mask, enabling you to implant the ions in the shape you desire in just one step," Leung says.
Outside of the semiconductor industry, the researchers believe that their technology could even replace lasers for certain micromachining applications. Because the ion beam is compatible with curved masks, the system is capable of cutting three-dimensional shapes.
For example, cardiac stents--mesh-like structures used to expand clogged arteries--are machined from steel with a laser beam that must be carefully steered. As a result, each beam can only carve out one stent at a time. According to Leung though, the ion beam imprinter "would allow hundreds or thousands of stents to be cut in one shot."
Currently, the researchers are developing ion sources to produce a variety of metallic ions, opening up even more applications for the new beam. Someday, Leung says, it could even become possible to use the system to fabricate magnetic quantum dots, nanometer-sized semiconductor crystals. Quantum dots may eventually be the basis of nanomemory chips that pack dozens of gigabits of data into a square centimeter.
Donald Brownlee is also the co-author of Rare Earth: Why Complex Life Is Uncommon in the Universe (photo courtesy NASA/JPL-Caltech) |
How many engineers have an asteroid named after them? UC Berkeley College of Engineering alum Donald Brownlee (B.S.'65 EECS) does. Interestingly, the world-famous astronomer spends more time looking through microscopes than telescopes.
A professor of astronomy at the University of Washington, Brownlee's research focuses on the small stuff in the big universe. He's a leading expert on interplanetary dust, studying extraterrestrial materials collected from space and the earth to gain insight into the origins of the cosmos. He's currently principal investigator for NASA's Stardust, a spacecraft that last January rendezvoused with Comet Wild 2 to collect cosmic material from deep space. In January 2006, Stardust will return to Earth bearing the samples in its high-tech dustbin for scientists to study.
Stardust encountered Comet Wild 2 on January 2, entrapping bits of cometary dust in its tennis racket-like collector. At about 800 pounds, the relatively low-cost unmanned craft is solar powered and flies close to Earth to get gravitational boosts during its journey. (photo courtesy NASA/JPL-Caltech) |
Before Stardust was ever a twinkle in NASA's eyes, Brownlee became well-known in the 1970s as the discoverer of cosmic particles in Earth's stratosphere. Each year, more than 10,000 tons of these "micrometeorites," known as Brownlee Particles, fall to Earth. By collecting the Brownlee Particles from the upper atmosphere and ocean floor, scientists hope to better understand the early history of the solar system.
As a senior at UC Berkeley in 1964, Brownleee launched a cosmic dust collector from the Greek Theater on campus. (courtesy Donald Brownlee) |
Brownlee's set his sights on space for the first time during his senior year at Berkeley as a student in the Department of Electrical Engineering and Computer Sciences. In 1964, he took an elective astronomy class on a whim and as his final project launched a cosmic dust collector suspended from a pair of high-altitude weather balloons. His next mission was a PhD in astronomy from the University of Washington .
"My engineering background has been a plus because most astronomers don't know a lot about engineering issues," Brownlee says. "A project like Stardust is primarily engineering: nuts and bolts, electronics, project management, the whole ball of wax."
Five years ago, Brownlee and another Berkeley-alum Peter Tsou (B.S.'65, M.S.'66 EECS), Stardust's deputy principal investigator and project engineer watched as the spacecraft was launched from Cape Canaveral Air Station. Next year, the precious cargo will be parachuted back to terra firma and Brownlee will again peer into his microscope to help uncover the secret history in the stardust.