Vol. 54, No. 24        November 29, 2002

Smart heat pipe makes for way-cool laptops • Researchers prepare to get a fix on microbes that trap carbon from air • Sandia to host first on-site master's program in national security • Dick Spalding's all-sky-all-the-time camera setup

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By Neal Singer

Laptops make laps hot, as users of mobile lightweight computers quickly learn, and things could get worse: upcoming chips may produce 100 watts per square centimeter -- the heat generated by a light bulb -- creating the effect of an unpleasantly localized dry sauna.

Current chip emanations are in the 50 watts/cm2 range.

More technically, increased heat generation is one of the great problems facing engineers trying to downsize circuit size or stack chips one above the other to increase mobile computing intelligence. Heat greater than 100 watts/cm2 can melt circuits.

"NASA researchers, as well as those working in military and consumer applications, are all bumping up against a thermal barrier," says Sandia researcher Mike Rightley (1745), who thinks he knows how to bypass it.

His group's newly patented version of a passively "smart" heat transfer mechanism uses small amounts of vaporized liquid sealed in tiny flat pipes to move heat to the side edge of the computer, where air fins or a tiny fan can dissipate the unwanted energy into air or even, in colder climates, into hand warmers, rather than undesirably into fabric and the flesh beneath.

"Because the new flat heat pipe design exactly duplicates in external form the less 'intelligent' heat transfer mechanism already in place, no internal redesign -- a bugaboo for computer makers -- is needed," says Mike. "Industry won't even see the difference. We'll just replace the heat sink with a heat pipe."

The method is being licensed to a start-up company "that has a very interested large customer in the laptop market," says Mike. A paper describing the work has been accepted for publication by Microelectronics Journal.

"We thought one application would be for a wearable computer for the military," says Mike. A box 6 x 1.5 x 4 inches could contain microprocessors, wireless Web cards, information from planes, AWACS information, and weather information on a hard disk with graphics capability and peripherals. "But using a fan to cool a field device will never work because of mud and muck and water. It's a perfect opportunity for heat pipe, to put the heat out to fins so the computer cools naturally."

In the heatpipe loop, heat from the chip changes liquid -- in this case, methanol -- to vapor. The vapor yields up its heat at a pre-selected site, changes back to liquid, and wicks back to its starting point to collect more heat.

Currently, typical laptops are cooled by a fan that merely blows the heat downward across a solid copper (formerly aluminum, when chips were cooler) plate that acts as a heat sink; thus, hot laps. The heat is spread rather than moved to a particular location. Such air-cooled spreading, says Mike, will work -- however uncomfortably -- until the hundred-degree range is exceeded. Then liquid cooling is essential.

"Formerly, thermal management solutions have been back-end issues," says Mike.

"It's clear now that the smaller we go, the more that cooling engineers need to be involved early in product design."

Powerful fans are electronically noisy

More circuits installed per unit area improve capability but reduce reliability, since increased heat increases the possibility of circuit failure; the problems are multiplied when chips are stacked one atop the next.

Currently, microprocessors in desktop computers have to be situated adjacent to a heat sink several inches high and wide, with attendant fan close by. This design problem creates enormous difficulties for designers interested in stacking chips for greater computational capacity yet reducing overall computer size. A further difficulty for the military is that powerful fans are electronically noisy and give away the location of the user.

A heat pipe can move heat from point A to point B without any direct geometrical relation between the points. This means that heat can be displaced to any desirable location, and a much smaller, quieter fan or even silent cooling fins can be used to dissipate heat.

The wick in the Sandia heat pipe is made of finely etched lines about as deep as fingerprints. These guide methanol between several locations and an arbitrary end point. The structure, which works by capillary action like a kerosene wick, consists of a ring of copper used to separate two plates of copper. Sixty-micron-tall curving, porous copper lines (slightly less thick than the diameter of a human hair), made with photolithographic techniques, allow material wicking directionally along the surface to defy gravity.

"An isotropic method [that sends out heat in all directions] doesn't work because it only cools the first heat source; you need anisotropic capability to cool all sources of heat directionally," says Mike. "We use laws of fluid mechanics to derive the optimum wick path to each heat source." The curvilinear guides can be patterned to go around holes drilled through the plate necessary to package it within the computer.

The computer program was developed by Chris Tigges (1742) and the device was modeled by Rick Givler (9114).

Paul Smith (1321), Chris, and Mike formulated the idea at a meeting two years earlier. Charlie Robino (1833) "figured out how to perform the microscale hermetic welding of the device," says Mike, who also expressed appreciation for technologists JJ Mulhall (1745), Mark Reece (1833), and Cathy Nowlen (1745).

The program is part of the Defense Advanced Research Project Agency's HERETIC program (Heat Removal by Thermal Integrated Circuits), a joint project of Sandia's with the Georgia Institute of Technology. - - Neal Singer

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By Nancy Garcia

The sky isn't exactly falling, but burning fossil fuel certainly has pumped enough greenhouse gases into the air to auger changes in global climate if concentrations climb higher.

For that reason, DOE is funding a suite of programs at the national laboratories, including one led from Sandia, that include an examination of the ways microbes remove carbon from the atmosphere. The Genomes-to-Life projects, announced recently (see July 26 Lab News), include this $1.1 million, three-year effort to gain a better fundamental understanding that can improve predictions of climate change.

Computations will be a key component of the effort, says principal investigator Grant

Heffelfinger (1802), involving both computer modeling and analysis of experimental data.

The winning proposal examines the role of so-called "molecular machines" that remove carbon from the atmosphere over oceans. The carbon-fixing systems are found in marine cyanobacteria, a type of blue-green algae particularly common among plankton floating on the surface of nutrient-poor regions of the ocean, such as the Sargasso Sea or equatorial areas.

"It's one of the most abundant organisms on the planet," says Tony Martino (8130), who is principal investigator on the project along with Brian Palenik, a professor at the University of California, San Diego who is affiliated with the Scripps Institution of Oceanography. Evolving some 4 billion years ago, this simple unicellular creature launched our oxygen atmosphere by being the first living thing to pull carbon from the air. With photosynthesis, it uses the energy of sunlight to build atmospheric carbon into sugar molecules, releasing oxygen (from atmospheric CO2) in the process.

Plankton and photosynthesis

In the ocean, cyanobacteria account for nearly half of the photosynthesis carried out by plankton. Since oceans are where 40 percent of photosynthesis occurs worldwide, Tony said, this lowly bacteria is "a major player in global climate change."

Unlike plants that carry out photosynthesis in chloroplasts (rodlike units whose sunlight-capturing pigment confers color to leaves in spring and summer), the bacteria contain simple protein shells full of enzyme. The enzymes in these

"carboxysome" structures catalyze chemical reactions in which carbon atoms are joined into loops or chains of sugars or starches.

Although carboxysomes were first identified in the 1970s, much remains unclear about them -- whether they house more than one enzyme, how they take in carbon, and when a particular synthetic approach is favored (since the known enzyme has dual activity).

"These organisms are not well understood at all," says Todd Lane (8130), a microbial expert on this and related projects. "To improve computer models of the global carbon cycle, we need to understand the biology of these organisms in the marine environment."

Previous models assumed there was a purely chemical process involved in the carbon cycle. But plankton that are energized by sunlight form a "biological pump" by "fixing" carbon from air into cell structures and then sinking to the ocean bottom upon death. Besides cyanobacteria, that process also occurs in marine diatoms. Slightly more complex than bacteria, these single-cell organisms have a lacey armature that makes them heavy enough upon death to very reliably sink to form an ocean-floor sediment. (Such sediments are where fossil fuels have been generated over eons from decayed organic matter.)

Iron is critical limiting factor

As a research assistant professor at Princeton University, Todd studied a marine diatom that demonstrated the first known biological use of a trace toxic metal, cadmium. Several trace metals act as nutrients to help the organism carry out photosynthesis. Zinc is one trace metal that influences the rate of photosynthesis. But iron, Todd says, is the critical limiting factor.

"It can kind of gasp along without zinc, but without iron, it's going nowhere. If you dump a lot of iron overboard, you can see a blue-green phytoplankton bloom."

The DOE project funding the carbon-sequestration research focused on delineating the sequence of subunits spelling out the genetic code for a closely related diatom to the one Todd studied, Thalassioria pseudonana. Todd recently returned from helping the DOE's Joint Genome Institute to annotate their draft sequence of roughly 9,000 genes.

The bacterium, by contrast, possesses just 3,500-odd genes and can be grown on solid agar medium so that colonies of clones (which appear as small dots on the surface of the nutrient gel) can be lifted out and grown for study.

Todd has a friend who lives near the beach in San Francisco collect seawater for growing these microorganisms in the lab. He adds nutrients and incubates them in a lighted cabinet warmed to a toasty 23 degrees C (about as warm as a warm spring day).

Molecular machines

The experimental group is focusing on three main "molecular machines" within the bacteria -- the carboxysome, trans-membrane protein complexes that actively transport nutrients and carbon across the protective membrane (called "ABC transporters" for adenosine triphosphate binding cassettes), and machinery that relays signals from the external

environment inside the cell, histidine-kinase response regulators.

The chief interest in the last two is the interaction of those molecular machines. (Their genes are near each other, so their production may be triggered together when the genes are switched on.) The physical relationship of molecular machines can be studied through new chemical analysis tools using mass spectrometry to reveal which proteins are present in complexes.

The scientists also plan to create entire arrays of tell-tale messenger RNA molecules that appear when genes are turned on, carrying instructions for making a unique protein based on the genetic code sequence.

Overall, Todd says, the three-year project will focus on applying "high-throughput" analysis to the molecular biology of these systems.

The team will be aided by a large computational effort aimed at acquiring, managing, and analyzing the vast array of genetic information to come forth.

In addition to Scripps, collaborating institutions include Oak Ridge National Laboratory and the National Institute for Genome Research in Santa Fe. Sandians teaming on the project include Diana Roe (8130), Dave Haaland (1812), Steve Plimpton (9212), Danny Rintoul (9212), and Jean-Loup Faulon (9212). - - Nancy Garcia

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By Nancy Garcia

Developing new leaders is a goal of a unique advanced-education program that is placing graduate-level courses at the Sandia/California site for the first time.

Beginning Jan. 6, 15 or more students are expected to begin taking courses on-site in the National Security and Public Safety Program offered by the University of New Haven, which has campuses in New England and Sacramento.

"We're offering unique courses to produce the next generation of leaders in the intelligence community," said Tom Johnson, dean of the School of Public Safety & Professional Studies.

The private university's graduate school focuses on offering career-oriented credentials and continuing education for mid-career professionals to respond to changes in the work environment.

The Sandia-based program is "so timely with what is going on in the world," says Sheryl Stewart (8522), who has worked for the last year to bring the program here. "Only 35 universities offer any national security-type programs."

The course of study, with evening, weekend, and some online classes, leads to three possible diplomas: a Masters of Science degree in National Security and Public Policy, a Masters of Science degree with a concentration in Information Protection and Security, or a professional certificate in National Security.

In the first trimester, from Jan. 6 through April 5, three core and three elective courses will be offered on Monday, Tuesday, and Wednesday evening. (A fourth course on military tribunals will be offered in March, and an online elective is also slated for the first trimester.)

Students apply to the University of New Haven to be admitted to the graduate school. Requirements include a completed baccalaureate degree from an accredited institution with a "B" average. To attend at the Sandia site, students must also be US citizens. The program is open to the public as well as laboratory employees. A clearance is not required; classes will be held in training rooms located in the Redwood Center. Sheryl encourages interested Sandians to complete their applications by Dec. 1 to ensure processing time before classes start in January.

Applicants and potential students say they see the program as both intrinsically interesting and a potential enhancement to their future work activities. Dee Dee Dicker (8516) received her bachelor's almost two years ago in management information systems (MIS). Among the first applicants to the Sandia-based program, she sees a partial tie-in to her work in handling increased security concerns regarding hazardous and radiological waste. She also was excited to potentially expand her career opportunities.

Todd Howe (8945), who also received a bachelor's degree in MIS, sees a tie between his interest in a concentration in information protection and his current assignment in computer support, as well as a potential preparation for moving within Sandia. "I'd rather be part of the big picture," he says. "I'm not so concerned with having a degree at the end as to learning something that I can apply."

Sandians pursuing a work-related degree can apply for the special degree program benefit through Education & Training (contact Ta'Rhonda Mayberry at tbmaybe@sandia.gov or 294-3142). By taking a full-time load of nine semester hours and working 20 hours a week, successful applicants receive their full salary and benefits and have tuition covered. Or, Sandians who take one or two classes can seek tuition assistance, for which they are reimbursed for up to $6,000 annually. (The University of New Haven program runs $475 per credit hour, and requires 36 credit hours to complete the master's degree.)

In addition to expanding educational experiences, the conveniently located courses were approved by Sandia management to help staff members gain a broader perspective of the national security context in which we carry out our mission, Sheryl says.

Classes will be taught by a diverse team of professors, instructors, and experienced professionals addressing national security from many perspectives. Sandians who are among the faculty for the upcoming program include researchers Fred Cohen, John Howard, and Gary Blair of Information Security Dept. 8910.

Applications are available online at www.newhaven.edu. Information is available from Sheryl Stewart, (800) 472-6342, extension 4-2428,

slstewa@sandia.gov; or University of New Haven Dean Tom Johnson, Ph.D., (916) 962-3136 or (203) 932-7260, tjohnson@newhaven.edu; or Colleen

Johnson, University of New Haven's Director of California Enrollment

Management, (800) 664-9368 Pin 00, crjohn@attglobal.net -- Nancy Garcia

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By Bill Murphy

A paper published in the Nov. 21 issue of the journal Nature makes a compelling case that multimegaton-sized asteroid and comet impacts with Earth aren't as common as had previously been thought.

The paper by University of Western Ontario meteor expert Peter Brown and four coauthors including Sandian Dick Spalding (5740) presents data indicating that impacts of the scale of the 10-megaton Tunguska event in Siberia in 1908 occur on average just once every 1,000 years. Previous best estimates put the frequency at closer to 200 to 300 years.

The new estimate is based on a sophisticated analysis of data from DoD and DOE satellites that monitor the planet for unusually brilliant flashes of light -- flashes that might be signatures of a rogue nuclear test.

Dick Spalding's involvement in the paper is based in part on his work as one of Sandia's resident experts on the satellite data cited in the study, but his interest in the field goes beyond that. The lights in the nighttime sky have long fascinated him, and he's convinced that if he were just able to watch the skies more closely, more completely, he'd see important phenomena that have never been credibly documented before.

In his quest not to miss a thing, he conceived of a way to watch the entire sky -- the whole sky -- all at once, all the time, 24/7.

Through his work with proliferation-monitoring systems, Dick knew that satellites not infrequently saw large inexplicable flashes of light, flashes that weren't necessarily being recorded from the ground. (It was this kind of data that formed the basis of the Nature paper).

Dick figured that if he could get "ground truth" -- a simultaneous recording of an event from the ground and from a satellite -- the resulting data could tell a lot more about the phenomenon than could satellite data alone.

The satellite typically records just the flash; a ground-based recorder -- or better, a series of ground-based stations -- could record direction, velocity, and trajectory data. That's the kind of information that could help a researcher figure out where in the solar system a fireball's object might have originated.

Pure science and ground truth

"A lot is known about the regular meteor showers, the Leonids, the Perseids," Dick says. "Less is known about the sporadics -- the occasional fireballs that don't show up here on any predictable schedule. It seems that the larger [fireball] events fall into the 'sporadics' category. Few systems out there capture this kind of [trajectory/velocity] data on sporadics; certainly, none of the imaging satellites do."

Dick's interest in this was pure science -- to know more than we do now about our cosmos. Additionally, "ground truth" can help analysts better understand and interpret the data collected by space-based imaging and sensor technology.

During the mid-1990s, there seemed to be a spate of fireball/meteor activity; Dick recalls an especially bright fireball in Colorado Springs that a private citizen caught on videotape in a most peculiar way.

"This was unusual," Dick says, "in that the individual just happened to have a security camera mounted under the eaves, pointing down toward his car in the driveway in front of his house. The fireball's reflection in the car's windshield was captured on videotape. We decided a domed mirror would do the job better. We even initially experimented with chrome hubcaps!"

There were similar large fireball events around the same time, notably the Oct. 9 El Paso and Dec. 9 Greenland fireballs, both in 1997.

"Although these large events were being seen by satellite, they weren't being recorded from the ground, so we weren't getting the kind of data that could tell us about their orbits. We began to realize that what we really needed to do was watch the whole sky -- all the time."

But how to do that? There were all-sky cameras available, but they were expensive dedicated high-end setups. Their cost made widespread deployment unfeasible -- and widespread deployment was central to the vision of real-time monitoring of as much of the sky as possible.

Off-the-shelf equipment

Being a Sandian, Dick is nothing if not resourceful: "Using a hemispheric security mirror and off-the-shelf video equipment -- a black-and-white video camera and some VCRs -- we were able to put together a prototype system; it was a cheap system, but it got the job done."

The setup was simple: aim the mirror at the sky, point the camera at the mirror, program the three VCRs to begin recording at eight-hour intervals and get 24-hour coverage.

Dick placed one of the first-generation all-sky cameras on the roof of Bldg. 890 and began looking for places to set up some others. Canada, it turns out, is a center of meteor science, probably because the ancient Canadian Shield geologic formation -- one of the oldest surface features on the planet -- contains a lot of meteorite impact craters. As a result, there is a concentration of meteor professionals in Canada. Dick was able to enlist a couple of his northern colleagues to take on the job of hosting all-sky camera systems.

Sandia researcher Mark Boslough (9216) learned about Dick's all-sky camera concept and thought it added a valuable dimension to an LDRD project he was involved in to study so-called near-Earth objects, those little-understood fellow travelers whose orbits intersect Earth's own track. Mark was one-half of the celebrated Boslough-Crawford team that did the computer model that predicted with startling accuracy the observable effects of the Shoemaker-Levy comet during its descent into Jupiter in 1994.

Genesis of sporadics not always clear

Mark says satellite data were indicating a lot of meteor events in the upper atmosphere, but adds that "there are a lot of these events whose genesis isn't completely clear. We were relying on serendipity, and that was kind of frustrating. We needed to get more systematic."

With better data, Mark knew, it would be possible not only to learn more about where fireballs originate, it might help pinpoint where they end up. In other words, with trajectory data, you have a lot better chance of pinpointing where to look for meteorites, whose composition can also tell a lot about the origin of the fireball -- and perhaps even of the solar system itself.

Big-name events

Mark remembered the famous Peekskill Fireball event. (Meteor researchers recall and refer to major events by name, the way a hurricane scientist might recall Camille or Agnes.)

The Peekskill event happened on a Friday night in October 1992, first appearing in the sky over West Virginia. Most high schools play their football games on Friday nights; there were plenty of parents and coaches with camcorders in the stands that night to capture the action on the playing fields. When the fireball streaked overhead, 16 different video cameras from West Virginia to Peekskill captured some part of the flight on tape. The data gave researchers enough information to calculate the original orbit of the fireball. One large piece smashed into the trunk of a 1981 Chevy Malibu in Peekskill, N.Y.

Mark saw right away that Dick's all-sky camera concept offered a way to replicate the Peekskill-level coverage on a full-time basis. He brought Dick into the LDRD, under the title "Collection and Data Synthesis of Atmospheric Explosion Ground Truth for Global Monitoring Systems."

With LDRD support, Dick was able to extend the network of cameras. There are now operating systems at Vancouver Island, Seattle, Edmonton, Calgary, Regina, Albuquerque, Los Alamos, Las Cruces, and El Paso.

The pieces of Dick's concept, then, were beginning to come together. Obviously, the network would need to be extended and the sky coverage expanded. More important, a way would have to be found to streamline the monitoring process. In its original bare-bones configuration, the all-sky camera recorded everything on videotape. Someone then had to scan the tape every day to look for the bright flashes that might indicate an atmospheric event. After a while, that task could be a big-time demotivator, even for a volunteer camera "owner" committed to the mission.

Joe's thesis project

Enter Joe Chavez (5733), a Sandian who was going for his CS masters at New Mexico Tech. Solving Dick's all-sky camera monitoring challenge offered a perfect thesis project. Joe conceived of and designed a low-cost computer-based system that tied into the all-sky camera rig. Joe's system included hardware and software that together could automatically detect, recognize, and save to a file the bright flashes and tracks in the sky that merited further investigation. The software saves the interesting parts as movie files.

"Each morning, as we scan through the collection of movies recorded throughout the night, Joe says, "we can usually easily tell if we have recorded a meteor or (more likely) just an airplane taking off from the airport."

As components get better -- and more available -- Dick hopes to see the all-sky network expand. In his most optimistic and imaginative moments, he envisions an all-sky meteor-watching network similar to the network of amateur weather stations that together provide comprehensive coverage of the US, all of their data available via the World Wide Web.

In the meantime, even though, as the Nature paper suggests, the big Tunguska-scale events may happen only once in a thousand years, Dick will be scanning the skies, watching. -- Bill Murphy

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