Masoud Agah, director of the Virginia Alliance for Semiconductor Technology, hopes to make an equal impact with his own SPOCK: the first-ever “miniature” chromatograph.

Although it sounds like something out of “Star Trek,” a chromatograph is a tool that analyzes the chemical composition of materials, such as water, soil, drugs, food, pollutants, and in the case of Agah’s size-segregated particle odor chromatograph kernel, or SPOCK, gases and aerosols.

“It’s the first of its kind, a truly miniaturized platform,” said Agah, who is also the Virginia Microelectronics Consortium Professor in the Bradley Department of Electrical and Computer Engineering. “There’s no equivalent with this size platform that also measures the chemical composition and physical properties of aerosols.”

Gas chromatographs like SPOCK analyze the chemical composition of gases, aerosols, or vapors to identify components, concentration, and impurities. These instruments are used in a wide variety of fields, including forensics, pharmaceuticals, the food industry, and environmental science.

How small can a chromatograph go?

The instruments vary in size, from industrial machines that take up entire rooms to the more portable versions about the size of a mini fridge. SPOCK, however, takes chromatography to its most portable and comprehensive version yet: a backpack-style instrument weighing less than 5 pounds that can identify chemical composition and morphologically reconstruct the aerosols in real-time — something that’s never been done at this scale.

Morphological reconstruction is basically the digital picture of an aerosol that reveals the size and shape of the particles. It’s an essential process for studying cloud formation, air pollution, climate change, and even optimizing the design of aerosol filters.

“In the atmospheric science community, our current chromatographs are portable but not like SPOCK,” said Gabriel Isaacman-Van Wertz,  associate professor in the Charles E. Via, Jr. Department of Civil and Environmental Engineering who has spent the last 15 years researching air quality and atmospheric chemistry. “With SPOCK, we can take it on the subway, bring it to a rainforest, take it on a walk – we can answer scientific questions and public security ones too.”

Because of its portability, applications for SPOCK are numerous, including national security, environmental monitoring, and industry safety.

Powered by futuristic tech

Packed with cutting-edge technology to reach its lightweight size and dual-function, SPOCK is made possible through patent-pending fluidic and electrical modular architecture (FEMI) invented by graduate students in Agah’s research group, Virginia Tech Microelectromechanical Systems.

Current non-modular systems use permanent glues or epoxies, meaning, if something goes wrong, breaks, or a microchip gets fried, the entire system has to be replaced. With FEMI, changes can be made quickly, and this removable mechanism is critical for the efficiency of SPOCK’s main systems and keeps it affordable for researchers like Isaacman-VanWertz.

In addition to the fluidic architecture, SPOCK has two main systems powered by an electronic computing unit:

• Modular size-segregated aerosol impact and chromatograph (MoSAIC): Much like its full-size counterparts, MoSAIC takes a sample of aerosol, vapor, or gas and then analyzes it with a “sniffer” that identifies chemical compounds, all on site.
• Particle imaging and counting cell (PIXEL): This imager uses an advanced chip-scale scattering-based optical device, which are tiny structures or particles that interact with light on a microchip. It’s basically a very tiny camera that analyzes the physical data of the aerosol samples.

Machine learning “on the edge”

As the director of a research group focused on machine learning and core faculty at the Sanghani Center for Artificial Intelligence and Data Analysis, Hoda Eldardiry’s expertise in machine learning “on the edge” — an advancing field of research — helps make SPOCK possible.

“The interesting thing about machine learning on the edge is you really want something that’s good enough to do the job and simple enough to run on the device itself – the machine’s edge,” said Eldardiry, associate professor in computer science. “The hope for our models is that they’ll be lightweight enough that they won’t require a lot of complex circuitry, making them time efficient and able to run real-time.”

Eldardiry will collaborate with the hardware teams working to build MoSAIC and PIXEL in an iterative design process to find the sweet spot of sensor size and computational power, ensuring it all fits in the planned backpack-size of SPOCK and maintains its powerful portability.

When the initiative concludes in about a year, this interdisciplinary and cross-country collaboration will not only result in a groundbreaking portable gas and aerosol analyzer, but also pave the way for future innovations in environmental monitoring and atmospheric science.

“What I’m really excited about is taking our gas chromatography research and shrinking it down,” Isaacman-VanWertz said. “By really taking advantage of technologies Masoud Agah is working on and combining it with Hoda Eldardiry’s machine learning, SPOCK will have an impact, and help advance the work of the atmospheric science community.”

SPOCK at a glance

Sponsor: Intelligence Advanced Research Projects Activity

Impact: SPOCK is the world’s first “miniature” gas chromatograph that analyzes chemical composition and physical properties and delivers real-time results, revolutionizing aerosol work in industry safety, environmental science, and national security. It utilizes patent-pending technology invented by Virginia Tech graduate students to float the microfluidic chips that power the dual analyzing components of SPOCK. The portable size of SPOCK means that researchers can answer new scientific questions and impact national security.

Team members:

• Virginia Tech faculty: Masoud Agah, Hoda Eldardiry, and Gabriel Isaacman-Van Wertz
• Consultant: Kevin Schug ’02
• Companies: CellsBin, Zebra Analytix, and Aerosol Dynamics