Magazine article Insight on the News

New Tools to Save Lives

Magazine article Insight on the News

New Tools to Save Lives

Article excerpt

Land mines are one of the more intractable problems in countries recovering from war. American researchers are working to find better ways to detect and defuse them.

An estimated 100 million land mines are buried worldwide. Some mined areas are so large that ground crews need parameters to make any progress at all. And although demining is expensive, buried mines present a real burden to developing counties. Unexploded mines isolate people in rural villages, discourage trade and prevent farming, according to CARE, a humanitarian relief organization. About 35 percent of the land in Afghanistan and Cambodia -- two of the most heavily mined countries -- remains unusable because of unexploded mines.

Teams searching for unexploded land mines beneath roads and fields in Bosnia-Herzegovina and other war zones use dogs and metal detectors. These methods are slow, inexact and risky,

"Dogs are great," says Nathan Lewis, a chemistry professor at California Institute of Technology and head of the "robonose" project that hopes to develop a device that sniffs out explosives. "But dogs get tired. They can only work two hours a day. And some days they don't want to work."

Lewis and his team are trying to discover how a dog knows it's sniffing a mine. "Dogs have no reason to know how to find TNT," says Lewis. He reasons that a dog must be able to sniff a whole scene and recognize certain smells.

Cal Tech's robonose uses chemical sensors to detect all the vapors in the air. Molecules in the vapors bind to various polymers (long molecular chains) in the sensor, causing them to swell. An electrical conductor mixed in with the polymers reacts to the polymers' increased size and resistance (each polymer responds differently to different vapors). Lewis hopes to use these differences to create a "smellprint" as unique as a fingerprint. …

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