Miniature sensors to advance climate studies, battlefield detection

a characteristic signature, for example.

“It would take a miniature pump the size of the last joint of your thumb to collect a sample,” Manginell said. “One can perform on-the-spot detection, but also capture a sample in the miniature chamber to send back to the lab for gold-standard tests.” E coli and anthrax also have volatile signatures, he said.

The detector also could be used by the military to collect and analyze gases on the battlefield.

“We’ve spent a lot of time over the past 15 years doing field analysis for customers: microchemlab work for the military and General Electric, and developing handheld gas detectors. This is just another tool in the toolbox,” Manginell said. “But we were pretty happy that this work proved to be broadly cost-effective.”

The work, featured in the paper, “A Materials Investigation of a Phase-Change Micro-Valve for Greenhouse Gas Collection and Other Potential Applications,” is a cross-department effort.

“This is a little different from what we’ve done in the past,” Manginell said. “The widespread collection of greenhouse gases has to be extremely cheap. So we collected people  who have done soldering, brazing and thick-film metallization on ceramics that’s scalable to high-volume production. Some did analytical chemistry to figure out if we were contaminating the sample. Others found the perfect solder mix.”

Sandia researcher Curt Mowry said, “I made sure the solder didn’t contribute any CO2 to the sample that was collected, because then you have a stinky measurement.”

More certainty in data collection is good because of the uncertainties in climate predictions, Manginell said.

“The overwhelming majority of the data seems to point to the fact that there’s warming, but how do you attribute that: Is it natural variation or manmade influence?” he said. “Distributions of our capsules would greatly improve the accuracy of field measurements. You’d have a platform that would be ubiquitous, on planes, UAVs, balloons in countries that can’t ordinarily afford to do these things. In India, it’s hard to make those measurements when you’re concerned with putting food on the table. But for legislation or policy decisions on, say, cap and trade, it’s important to make those measurements accurately.”

Funding came from Sandia’s Laboratory Directed Research and Development (LDRD) program, Manginell said.

“We thought we could do a more ubiquitous job of sensing than anything currently available,” he said.

Despite successful testing of the device, Manginell’s work, like science, is never finished. “What we need to build next is a normally closed version of the valve that opens when we want it to,” he said. A presealed container would eliminate another possible source of contamination in transit.

— Read more in Ronald P. Manginell et al., “A materials investigation of a phase-change micro-valve for greenhouse gas collection and other potential applications,” Review of Scientific Instruments 83, no. 3 (13 March 2012)