By Patti Koning
Where the surf hits the sand — beaches — are places of unique physical beauty and natural recreation. Beaches figure prominently in most memories of childhood and are firmly cemented in popular culture. Think of the Beach Boys, Beach Blanket Bingo, or the thousands of cities with “beach” in their name.
Shifting tides mean that beaches are never quite the same from one hour to the next. This quality presents a challenge for physical security at what is referred to as the “land-water interface” or LWI.
“This hasn’t been done before,” says Michael Ross (6481). “Sandia has expertise in land barriers and there are mature surface barriers and active acoustic technologies for deeper water, but what’s missing is the interface between the two — especially in the littoral zone [the zone where sea and shore meet].”
Michael is the principal investigator for a project to develop a solution to this problem. The idea is create something called a “defeat barrier” that will extend from the shore out as far into the sea as necessary.
The project is a collaboration with the Applied Physics Laboratory (APL) at Johns Hopkins University. Sandia provides the expertise in physical security on land, while APL has the underwater expertise.
The defeat barrier combines simple physical security — a grate-like fence — with detection technology to sense a breach. Along with the barrier, other technologies are used to detect movement under water or climbing over or under the fence, and a variety of cameras provide alarm assessment and situational awareness. The defeat barrier itself will extend from below the sea floor to above the high tide level, and the length will depend on the physical characteristics of the site.
While the concept is relatively simple, deploying it in a marine environment throws layers of complication at the problem. The complex littoral environment, says Michael, drove the design decisions.
Any barrier for physical protection must fit into environmental constraints. The obvious solution would be a solid causeway extended into the water to the point where deeper water technologies can take over.
“The littoral area is environmentally sensitive,” says Michael. “You have to allow water and small wildlife to pass through any security system. It’s a challenge to create a design that meets the security requirements and is environmentally friendly.”
The marine environment also presents a number of unknowns, as many of the components have never been used in salt water. The defeat barrier and other physical protection system components are being deployed at a test bed in Florida for performance measurements and to see how they handle salt water and extreme weather over the long term. Don Sheaffer (8136), an electrical engineer working on the project, says that biofouling could be an issue, if the sensors and other equipment need frequent cleaning.
“This defeat barrier must have a zero false alarm, zero nuisance alarm rate. Any failure is catastrophic,” he adds. “And how do you install the defeat barrier so it is sturdy enough to withstand whatever Mother Nature might throw at it? We’re going to find out.”
In March, Sandia initiated video assessment testing. Using an existing pier off the Florida beach, video cameras are detecting movement in 180 different scenarios.
What happens in extreme fog? At sunrise and sunset? When the noonday sun reflects off the water? What if an intruder is dressed in black or silver? Ten-second clips showing breaches in these conditions and others will be shown to a team of 30 potential operators of the system.
The mechanics of the defeat barrier are automated — any breach would set off a sensor alarm — but the final assessment is always made by an operator monitoring video images captured from the area where the alarm was produced. The defeat barrier’s effectiveness is only as good as those images.While Michael’s team is designing and testing a physical protection system specifically for one customer, the concept could be applied to any land-water interface, including fresh water and marshy areas. “We’ve had interest from the Department of Homeland Security and the organizers of the London 2012 Olympics,” he says. “The perimeter that needs to be secured in London is not entirely on land.” -- Patti Koning
By Patti Koning
Summertime means longer days, warmer weather, and often, a break from the regular routine. For a number of Sandians, that break includes mentoring an intern through the Enabling Predictive Simulation Research Institute (EPSRI) [www.esc.sandia.gov/epsri]. This program, now in its second year, brings dozens of graduate students from across the country to Sandia to work on focused projects in the engineering sciences.
“The interns gain a sense of what kind of engineering and research work is happening here and they get to experience our research-oriented and collaborative environment,” says Jonathan Zimmerman (8776). “The mentors get a sense of research happening outside the Laboratory in the academic community and how our work relates.”
The EPSRI started last year as a joint effort between Centers 8700 and 1500 to perform cutting-edge research and development that enables the application of predictive simulation capabilities. Jonathan coordinates the EPSRI program in California, along with Scott James (8757) and James W. Foulk III (8776). The New Mexico program is coordinated by Basil Hassan (1541).
This summer, 30 interns split evenly between the California and New Mexico sites spent 10 weeks working in technical areas such as structural dynamics, solid mechanics, material mechanics, electromagnetics, electrical science, and thermal, fluid, and aero sciences.
During the summer, EPSRI hosts a series of staff technical talks for the interns. “The purpose is to give the interns a flavor of how we use our engineering education to tackle the problems we face here,” says Jonathan. The students present their work in a seminar at the end of their internship.
Each student is paired with a mentor, whose technical area complements that of the student. Ideally, the project a student works on while at Sandia ties directly into his or her thesis project.
Timothy Kostka, a graduate student in mechanical engineering at the University of California, Berkeley, says Sandia is the only institute he knows of where he can do modeling and predictive research with a team of collaborators using large-scale computing resources.
“Having access to the computational power of Sandia and many great people is a unique opportunity,” he says. “I’m working on really interesting stuff, not busy work, that will help me with my doctorate.”
This is Timothy’s second year as an EPSRI intern; he also spent two summers interning at Sandia while he was an undergraduate at Cornell University.
Another EPSRI intern is Garritt Tucker, a graduate student in computational mechanics and materials at Georgia Tech. “I’ve been able to see really interesting work, things I never considered for my PhD research,” he says. “It’s a great opportunity to see things on a grander scale.”
This summer, Garritt worked with Jonathan on atomistic simulations of deformation of microstructural features, looking at different fields of stress and deformation that are specially defined at small scales. This work helps identify key physical features of nano-structured materials that are needed to construct predictive engineering-scale models.
While EPRSI is only two years old, Center 8700 has been doing an engineering sciences summer institute for the past 10 years. Such programs provide a pipeline for new hires and strengthen ties with the academic community. Jonathan estimates that at least 10 former engineering sciences interns have been hired into Sandia in as many years.
Michael Jew (8774) interned at Sandia during the summer of 2002, when he was a graduate student at UC Berkeley. “Being an intern at Sandia was really eye-opening, in a good way,” he says. “I didn’t expect the campus-like environment here, or all the different disciplines at such a relatively small site.”
Former Sandians who have gone on to careers in academia also continue to send their students to the program. In the program this year are graduate students of two former Sandians: Richard Regueiro, an assistant professor in the Civil, Environmental, and Architectural Engineering Department at the University of Colorado, Boulder; and Mark Horstemeyer, a mechanical engineering professor at Mississippi State University.
Neville Moody (8758) has mentored some 25 interns and postdocs over the past 15 years. This summer, he’s taken under his wing John Yeager, a materials science graduate student at Washington State University. Years ago, Yeager’s advisor, David Bahr, interned with Neville. (Neville’s relationship with Bahr started at the University of Minnesota, where they shared an advisor.)
“It’s been great to work one-on-one with Neville. The equipment here is great and I’m getting a lot more done here than I would at my university,” says John.
Over the summer, John worked with Neville on a project testing flexible substrate materials. The testing method is different than the one John has been using at school; for his thesis, he’ll compare the two methods. The project is part of a Laboratory Directed Research and Development project, on which Bahr is a collaborator.
“Having an intern adds a great dimension to the work environment,” says Neville. “Students bring a fresh perspective and they are totally dedicated to the work, since it’s often part of their PhD project.”
John is partially funded by Sandia, and hopes to be back as soon as next spring after he finishes his last two classes. He’d like to extend his stay at Sandia as a postdoc after he graduates. — Patti Koning