URI chemical engineer developing sensor to detect explosives

Otto Gregory’s findings published in Electrochemical Society Transactions

KINGSTON, R.I., Dec. 29, 2015 – Dogs have been used for decades to sniff out explosives, but now a University of Rhode Island scientist and his team have come up with another way to detect bombs: sensors.

Otto J. Gregory, professor of chemical engineering and co-director of URI’s Sensors and Surface Technology Partnership, has developed a sensor that can detect explosives commonly used by terrorists. One of these explosives is triacetone triperoxide, or TATP.

Triacetone triperoxide has been used by terrorists worldwide, from the 2001 “shoe bomber” Richard Reid to the suicide bombers who attacked residents of Paris in November. The explosive is relatively easy to make with chemicals that can be bought at pharmacies and hardware stores, attracting little attention from authorities.

Gregory’s work focuses on creating a sensor that continuously detects vapors emitted by the explosive.

Here’s how it works: A tin oxide catalyst in the sensor causes the triacetone triperoxide molecule to decompose at a specific temperature. The sensor monitors the amount of heat released by the decomposition and triggers an alarm.

“We initiate the decomposition of the molecule using a catalyst and then measure the heat released,” says Gregory, of Kingston. “If the amount released can be measured, we can identify the molecule responsible.”

What makes Gregory’s research—published in the journal Electrochemical Society Transactions—even more significant is that his sensor could be used round-the-clock in various public places, from boarding areas in airports and subways to ports of entry for cargo containers.

“If someone carrying TATP were to walk by in a relatively confined space, the sensor could detect it,” he says. “It works 24/7.”

Gregory says sensors are the future of trace explosive detection systems. Not only does his sensor detect TATP, it can also determine if ammonium nitrate, TNT and other explosives are present.

Dogs can still be trained to track down explosives at very low levels, but sensors are a better long-term solution to continuous screening of these substances, Gregory says.

“Dogs have short attention span and can be distracted,” he says. “For the first hour or so, they’re really good at detecting explosives. Then their minds wander. It’s like a little kid. What our sensors do is continuously sniff 24/7. Dogs need to rest for periods of time.”

The next step is to reduce the sensor to a manageable size—maybe the size of a shoebox or smaller. Meanwhile, Gregory and his colleagues at URI will continue to play a key role in making the world a safer place.

“URI professors and students are doing cutting edge research in the areas of explosive characterization and detection,” he says. “We’re trying to make buildings, stadiums, airports and subways safer for the traveling public. Our research will go a long way in achieving this goal.”

Gregory’s work is funded by the U.S. Department of Homeland Security. In 2008, URI was awarded $5.15 million from the federal agency to launch a Center of Excellence in Explosives, Detection, Mitigation, Response and Characterization for research on explosives and detection of explosives. URI has received additional funding since then.

“Faculty and students at URI have partnered with the Department of Homeland Security to research explosives and explosive detection methods,” Gregory says. “In the process we have addressed some of the safety and security concerns, both here in the United States and abroad.”

Gregory’s research team is also working on sensors for jet engines that would make aircraft safer and more reliable. Part of this research focuses on ways to eliminate messy wiring by relying on wireless sensor technologies.

Gregory received his bachelor of science degrees in chemical engineering and ocean engineering from URI in 1975, a master’s degree in chemical engineering from URI in 1977, and a doctorate in engineering from Brown University in 1983.

He has researched sensors for harsh environments for more than 30 years and has authored or co-authored 90 peer-reviewed journal articles that have provided background for 25 U.S. patents. In addition to Homeland Security, he has received funding from NASA, the National Science Foundation, Department of Energy, Defense Advanced Research Projects Agency, U.S. Army, U.S. Navy and private industry.