For the past three years a Sandia research team headed by Mat Celina (1821) has been investigating the performance of various piezoelectric polymer films that might one day serve as ultra-light mirrors in space telescopes.
In 2007 the research will go one step further when a Labs’ experimental package of promising polymers will be part of a NASA experiment on the upcoming Materials International Space Station Experiment (MISSE-6) to be launched into low Earth orbit (LEO).
“This will be the first time these polymers will be remotely operated in an actual space environment,” Mat says. “We hope to learn which polymer materials will work best in space. The materials will boldly go where they have not been before.”
Sandia delivered the package to NASA in May, and it will become one of many polymer performance experiments conducted on MISSE-6.
Lightweight piezoelectric polymers based on polyvinylidene fluoride (PVDF) and its copolymers expand and change shape when an electric field is applied. They have not been used much in space because they degrade when exposed to the conditions of LEO, such as atomic oxygen, solar UV (ultraviolet), and temperature variations.
To be successful as space mirrors, the polymer films, which would be covered with a metallic coating, will have to be able to survive the rigors of space.
Space telescopes equipped with piezoelectric polymer films will be quite different from the Hubble, which was deployed into orbit in 1990 and uses the traditional polished glass mirror approach, and the James Webb Space Telescope scheduled for launch in 2013, which will be made of 18 beryllium mirror segments. Instead, the new polymer film mirrors would be lightweight, and — because of their piezoelectric qualities — could adjust focal lengths when electrical fields are remotely applied.
“NASA and Boeing have been running experiments with polymers in space for some time,” Mat says. “The space materials community first looked extensively at polymers in space in the late 1980s. They launched a large satellite, the LDEF (Long Duration Exposure Facility), and found significant polymer degradation issues. The Hubble had polymer degradation problems as well, with its thermal control blankets.”
The research team spent the past three years developing and testing polymers in an effort to identify the ones that just might work best.
“We did many experiments on the ground both at Sandia and with the support of NASA-Glenn,” Mat says. “We managed to do as complete a testing as possible before we put the polymer films in space. Our [former] postdoc Tim Dargaville was instrumental in conducting a comprehensive evaluation program. Many other Sandia staff with specialized equipment also assisted.”
As part of the experiments the research team measured how the piezoelectric material would change in different circumstances and identified a range of materials.
The team experimented with a variety of polymers, including some that were off the shelf and others that were specially created.
After coming up with the most promising polymers, the materials were placed in a 6-inch by 6-inch sample holder designed by Gary Jones that is part of the MISSE-6 experimental package. This experimental unit will be launched as part of a larger suitcase-type container where experiments from a range of universities and other agencies will be assembled as well. Astronauts will attach the container to the International Space Station during a spacewalk and will open it inside out to expose the samples.
Depending on which side of the container the samples are located, they will either receive primarily vacuum UV (VUV) radiation or both VUV and atomic oxygen exposure. Both passive experiments, which are not hooked up to electric excitation, and active experiments, which will be connected to high voltage, will be flown, allowing for a range of experiments and materials to be tested over the course of the exposure — estimated to be six to eight months.
The degradation trends and loss in performance caused by exposure to the space elements will be monitored in real-time and logged into NASA-qualified data-loggers. When the loggers are returned to Earth, Sandia researchers will analyze the data to determine which materials were able to best survive the harsh space environment. Mat anticipates it will take at least one year to evaluate the materials and data to decide which polymers might be best suited for space mirrors.“This work has been really interesting and a personally rewarding and challenging project,” Mat says. “We’ve done fundamental science on the piezoelectric polymers and, once the experiment in space is completed, we’ll be able to provide real scientific feedback to engineers intending to use such polymer films in space.” -- Chris Burroughs
By Neal Singer
Researchers have been interested for at least 25 years in understanding interactions taking place underwater between materials, but stymied in their ability to observe, quantify, and explain them.
When flat water-hating surfaces approach each other underwater, scientists have observed that they snap into contact. This is due to attractive forces that extend for tens to hundreds of nanometers.
These distances are unexplainable by conventional theories, which find no naturally occurring local force strong enough to accomplish this task.
In a paper published Aug. 3 in the journal Nature, Sandia researchers were able to increase the distance from nanometers to microns of what may be the same interaction. The new conditions may help explain the unexpectedly long-range attractions of hydrophobic surfaces under water.
One change was this: Rather than using merely smooth hydrophobic surfaces, the materials were rough superhydrophobic surfaces on which water droplets roll like marbles.
Superhydrophobic surfaces can be formed simply from a silica solution by an evaporation-driven assembly process developed by Sandia Fellow Jeff Brinker (1002).
“Previous experimentalists had always used smooth materials — but most common materials are rough, and roughness greatly influences the interaction with water,” says Jeff.
The group’s observations indicated that two superhydrophobic surfaces approaching each other force the water between them to change state to a vapor, creating a cavity. This cavitation event is characterized by less internal pressure that may be the cause of a very long range attractive interaction and possibly of longer-scale version of the unexplained interactions seen to date for smooth surfaces.
In addition, a microscope that resists the “snap-together” effect enabled the Brinker group to measure the forces involved as the surfaces closed upon each other.
The microscope, called an Interfacial Force Microscope, was developed at Sandia under the direction of Jack Houston (1114).
Unlike the Atomic Force Microscope, the IFM actively resists “snapping” because of a kind of teeter-totter built into its observational tip. Through this resistance, the group slowed the “snap” into a longer time frame that allowed step-by-step observation of what exactly was happening in the formerly indecipherable moment.
“When force becomes overwhelming for an AFM, surfaces snap together uncontrollably,” says Jack. “The IFM just measures the force without caving in to it. We can move in as slowly as we want until we reach the point of contact.”
“There’s no other instrument that can do that,” says first author Seema Singh (1815), who did the experimental work under direction of Jack and Jeff.
“Seema Singh is a phenomenal experimentalist who really enabled all this stuff to happen,” says Jeff.
Although rough superhydrophobic surfaces have been of much recent interest for their self-cleaning properties (the so-called Lotus effect, where rolling drops of water cleanse such surfaces of particles and parasites), their interactions underwater have not been studied.
The superhydrophobic material was self-assembled by simply drying a slurry of hydrophobically modified silica in a technique originally developed to create super-low-density silica aerogels. During drying, the silica gel shrinks and re-expands to create a rough rather than smooth surface. The roughness creates a spike-like effect causing a water drop to adopt an almost spherical shape.
“This greater hydrophobicity apparently increased the distance over which cavitation could occur, allowing it to be visually imaged for the first time,” says Sandia researcher Frank van Swol, who calculated the theoretical cavitation distance and the energy and forces associated with cavitation.
The improved observation led the group to conclude that cavitation may be responsible in general for the hydrophobic interactions that exceed the known range of van der Waals forces.
The work was funded by Sandia’s Laboratory Directed Research Development (LDRD) office and then by DOE’s Office of Science, and the Air Force. The paper was authored by Seema, Jack, Frank, and Jeff.
-- Neal Singer
By Neal Singer
Michael Dell, chairman of Dell Corporation who in 1992 became the youngest CEO of any company listed on the Fortune 500, visited Sandia last Friday to tour Sandia’s Dell Thunderbird supercomputer and sign a commemorative plaque with Laboratories Director and President Tom Hunter.
Crowning the success of Dell’s entry with Sandia into the supercomputer market, the Sandia Dell Thunderbird is currently the sixth fastest supercomputer in the world on the widely accepted Linpac test. At its $15.2 million price tag, it is the cheapest per flop of any general-purpose supercomputer of its scale anywhere.
The signing took place in the Visualization facility at JCEL (the Joint Computational Engineering Lab). Tom and Dell spoke briefly on what supercomputing will mean to US industrial competitiveness and national security in terms of transforming engineering and science.
“This has been a truly remarkable partnership. I look at success in many ways, but this one has been outstanding. Leaders look at today’s norms and say, ‘tomorrow must be different.’ This project shows that we are doing that with Michael Dell, who has helped shape the way the world is thinking about information technology,” Tom said.
Sometimes referred to as the “Henry Ford of computers” for his success in bringing a technological product to market, Dell said, “All the great problems in physics, chemistry, and biology are really computational problems. We now have a great amount of computational power deployed at lessening institutional cost. We’ve done this in partnership with Sandia, using industry-standard technology. It’s fascinating to me to see our product used at Sandia in the great work you’re doing.”
A video produced by Sandia’s Regina Valenzuela (6039-1) showed the Thunderbird cluster in action. The highly original piece opened by showing a caterpillar turn into a butterfly, and then switched images to say that “the transformation from slide rule to supercomputer is as mysterious as any transformation in nature.”
Preceding the pageantry of the signing, which took place late in the day, was an early morning signing of an agreement that detailed future cooperation between the Labs and the computer company.
The agreement was signed by Sandia Div. 1000 VP Rick Stulen and Dell VP Jennifer Smith.
“The extraordinary results we have obtained to date on the Dell Thunderbird cluster are representative of the future of simulation-enabled engineering. Our agreement with Dell will enable our partnership to continue to focus on the future of high-performance computing,” Rick said.
One reason for the success of the 8,960-processor Thunderbird cluster — designed jointly by Sandia and Dell — is that Sandia and Dell were willing to gamble on a new “interconnect” technology that communicates between computer nodes. The interconnect, called Infiniband, had never before been deployed in a computing system of this scale or complexity. The ready availability of this now-proven component as an “off-the-shelf” commercial product may lead to an increase in the number of supercomputers worldwide by improving speed while lowering prices. -- Neal Singer
When you first enter Sandia’s nationally recognized Center for Cyber Defenders — known as the CCD — you may find yourself wondering if you’ve inadvertently stepped into a university’s computer science lab.
As it turns out, the collaborative peer-learning environment of college is exactly the concept behind the Cyber Defenders program.
The large room, buzzing with the activity of students and the hum of computer workstations, is the place students of the Cyber Defenders program call home.
Ryan Custer (5616), now a full-time Sandia employee, was one of the nearly 90 students who have participated in the CCD to date. The teams of students have developed a reputation for their remarkable speed and effectiveness in completing projects — a direct result of their ability to instantly consult with their peers, says Ryan.
“If there’s something you don’t know the answer to, if there’s some code you’re unfamiliar with,” says Ryan, “all you have to do is shout out, ‘Hey, what do you know about this?’ and you’re guaranteed to get at least a few knowledgeable people right there helping you.”
While a student with the CCD, Ryan collaborated with fellow student Erik Lee (5616, now also a Sandian) to design a suite of tools that presents a human with a way to visualize events as they occur on a network. Together, Ryan and Erik developed a variety of ways to visually interpret the huge amounts of information flying across a network. By using these visualization tools, an operator can watch a detailed, real-time representation of a network, and thereby gain insights into the behaviors of that network.
This is a valuable tool because the human brain cannot quickly or easily interpret the massive amounts of data created by a network. As a result, nearly all network analysis, particularly intrusion detection, had to be done “post-mortem” and was time-consuming. Now, with these tools, a grouping of spheres and lines traveling across different planes of view represent ports and connections — views that make use of the rapid visual processing capabilities of the human brain — and can give instant feedback about a malicious distributed denial-of-service attack on a network, or a scan of network ports.
Through projects like this, the CCD is making significant advances in network security.
“Our goal is to address homeland and national security needs while providing a way for students who are interested in information assurance to be exposed to the challenges of those needs while in a research environment,” says program manager Bob Hutchinson (5616). “We looked at the caliber of students coming out of colleges, and how well-versed they were in today’s computer sciences, and thought to ourselves, ‘There really isn’t anyone more qualified than these people to take on the emerging challenges facing our technology.’”
As a result, the CCD currently employs nearly 20 students who represent the most knowledgeable and passionate students of those in their field. The mentors and staff of the Cyber Defender program have developed a unique environment that provides students from varied computer backgrounds with cutting-edge research projects while instilling them with new skills.
“By providing a collaborative pool for these students, they are able to solve the challenges presented to them incredibly efficiently and effectively,” says Bob.
The CCD has actually provided such a strong talent pool to Sandia that nearly a quarter of the students who participate in an internship with the program go on to be hired as employees by the Labs. Additionally, the work performed by CCD students has gone on to reshape the computer science curriculum at several universities across the nation.
“People may not realize how much we learn from these students, as well,” says Bob. “We’re here mentoring them, but so many times we hear back from people who have worked with our students as mentors on projects and have come away having learned more from the student than they had ever expected.”
The Cyber Defenders program began in 1998 at Sandia/California as a collaboration between the DOE Defense Program’s Education Department, faculty members at Las Positas and Chabot Colleges, and Sandia information security experts.
Today, the program spans both Sandia sites and employs between 20 and 30 students each year in a wide variety of information technology, information protection, and distributed computing projects.
Since the program’s creation, participants have racked up an impressive record of accomplishments that includes creating a database of known attack techniques and defense methods, analyzing hundreds of published attack techniques gleaned from Internet sites, and building prototype networks that demonstrate concepts now being used in cyber-infrastructure protection at Sandia.
The projects that the students take on come from a variety of places within Sandia. Through collaborative projects in digital forensics, supercomputers, and safeguards and security, the CCD has contributed to a broad range of work at the Labs.
“It has been rewarding to watch the CCD grow and evolve,” says Bob. “It’s really become an asset to the entire laboratory.”
Boot camp beginning
This year also marked the first pilot run of the CCD Cyber Security Boot Camp. The boot camp is a three-day, hands-on program designed to cultivate interest in computer science at the high school level.
In the inaugural run of the boot camp, six high school freshmen participated in a series of skill-building computer projects. The events began with an overview of how computers work, leading to a course during which students built their own computer from the ground up and then loaded an operating system onto their freshly built machines.
Over the remaining days of the boot camp, the students learned how to choose secure passwords, create their own network cables, and “ping” a computer to determine whether a specific Internet protocol (IP) address is accessible. Before wrapping up, the CCD gave the students a thorough explanation about how viruses, worms, trojans, and spyware take advantage of vulnerabilities to exploit, and even destroy, information on computers and the role that antivirus software and firewalls play in securing computers against such attacks.
“The kids were really amazed to see not only how capable they were of building something as complex as a computer, but also how easy it was to protect that computer against attacks through things like carefully designed passwords and antivirus programs,” says program coordinator Karen Shanklin (5616). “The boot camp has proven to be a very valuable resource.”The CCD plans to offer the boot camp annually, and semiannually if demand for the program continues to grow. -- Darrick Hurst