According to the United Nations, there are more than 100 million active land mines buried underground in 64 countries around the world. The presence of the mines not only endangers the lives of the people that live near them, it also affects their livelihood. Acres of land that could be used for farming or infrastructure are avoided because of the potential threat of mines or improvised explosive devices (IEDs). Laying mines is usually a straightforward and easy process, but detecting and disarming them is quite another.
Current methods of detection use dogs or robots. But "...with animals, you can't switch them on and off like a machine and they are sometimes difficult to work with," said Erik Tollefsen, advisor for stockpile destruction, EOD and technology for the Geneva International Center for Humanitarian Demining.
Researchers from the University of Connecticut are working on a solution that involves a fluorescent nanofiberous film. The film they developed contains chemicals that detect trace levels of explosive vapors from mines underground. The idea is that the nanofilm could be rolled out over a piece of land like out a giant roll of paper towels. Because the film is so light, there would be no threat of setting off a potential mine.
After laying over the ground for about 30 minutes,the chemical sensing system is activated by an ultra-violet light to detect the organic compounds that explosives like TNT emit. The system can even sense plastic explosives like HMX, a compound used in explosives during World War II. When emissions are sensed, the fluorescent color darkens and a circle appears, identifying where the vapors are coming from.
"A UV light may be applied as a searchlight and coupled with a digital camera, so the results could be transmitted back to the control center," said Ying Wang, a scientist on the project.
If no threat is found, the film maintains its fluorescence and doesn't get darker. The process takes minutes and is relatively cheap thanks to the thin and lightweight material than can span a large area. Engineers from UConn point out the sensor could even be incorporated into a small paper test strip for a low-cost method of detection. Further testing will be under way soon. Dr. Wang told Discovery News that a large-scale field test in Sweden is in the process.
Credit: University of Connecticut