URI chemical engineering professor developing explosives-detection sensor

Sitting before the keyboard of his electron microscope, Professor Otto Gregory, right, a chemical engineering professor at URI, speaks with Michael Platek, an electrical materials engineer.  / COURTESY OTTO GREGORY
Sitting before the keyboard of his electron microscope, Professor Otto Gregory, right, a chemical engineering professor at URI, speaks with Michael Platek, an electrical materials engineer. / COURTESY OTTO GREGORY

SOUTH KINGSTOWN – 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, engineering 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.

TATP has been used by terrorists worldwide, from the 2001 “shoe bomber” Richard Reid to the suicide bombers who attacked several venues in Paris in November 2015. 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.

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Here’s how it works: A tin oxide catalyst in the sensor causes the TATP 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,’’ said Gregory, of South Kingstown. “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 around-the-clock in a diverse array of 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,’’ Gregory said. “It works 24/7.’’

Sensors, said Gregory, 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.

“Dogs have short attention spans and can be distracted,’’ he said. “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 URI colleagues 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 said. “We’re trying to make buildings, stadiums, airports and subways safer for the public. Our research will go a long way in achieving this goal.’’

The U.S. Department of Homeland Security is funding Gregory’s work. 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,’’ he said. “In the process, we have addressed some of the safety and security concerns, both here in the United States and abroad.’’

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