Landmines pose an ominous threat to military personnel and civilians in war ravaged countries the world over. Official estimates put the number of landmine casualties at 500 per week on a global scale.
Despite the wealth of proposed hi-tech detection solutions it is the humble canine – with its unique olfactory senses – that comes out top in the mine detection league.
Dogs, however, are expensive to train and have a short attention span but research from Penn State University may allow further development of an artificial dog’s nose to undertake the daunting task of mine clearance.
Garry Settles, a mechanical engineer from Penn State University, has unlocked the mechanism that gives the dog its amazing sense of smell.
‘It has become important to understand and eventually mimic canine olfaction for purposes of unexploded ordnance detection,’ stated Settles.
Settles studied dogs breathing and smelling patterns using high magnification canine nostril videography and a technique sensitive to warm air currents called Schilieren photography.
Results showed that a dog’s acute sense of smell comes partly from its ability to divert exhaled air away from a target scent. When a dog exhales it moves its nose so the air is deflected through slits on its side causing the exhaled air to flow backwards, away from the smell.
This separates exhaled air from the scent and sets up a current that pulls new air across the target scent, launching odour molecules into the air.
Researchers at Tufts University are utilising Settles’ results to modify their existing artificial nose so that it mimics the way dogs sample air.
Odour molecules are removed from the air stream and detected by sensors that can then use the exhaled air as a baseline measurement. The difference in odour molecule concentration between this baseline and the inflowing air is what allows the system to register a particular smell.
By combining the dog’s nose air sampling and existing chemical sensing techniques, the artificial nose has successfully detected mines in field tests.
The U.S. Defence Advanced Research Projects Agency is also using Settles findings to develop an artificial nose to detect unexploded ordnance.