Detector - Scientists are working on a way to connect a computer
to living things, and the effort could help protect us from bioterror.
Detector - Nearly a year after the anthrax mail attacks we
still have a long way to go for that perfect detector. (8/30/02)
Elsewhere on the web
Role of Sensing & Sensors - Sandia Technology
Nanotechnology research for homeland security and national defense
also goes on at MITâ€™s
Institute for Soldier Nanotechnology and Florida
If you worry about war coming home, in the form of bombs or bioterror, there
are some high-tech defenses in place. One is an extremely efficient sensor
in our airports and subway stations.
As this ScienCentral News video reports, the new device is particularly sensitive
to hidden explosives or chemical weapons like nerve gas, thanks to a special
component that was inspired by tumbleweed.
Rolling Homeland Security
Around Sandia National Laboratories
and the University of New Mexico in Albuquerque, where senior scientist and
Jeffrey Brinker develops new materials, the windy late-winter months can
choke paths and gardens with
Brinker was struggling to clear piles of the rolling irritant off his lawn,
when he realized that while tumbleweed takes up a great deal of room, it is
actually mostly open space, with very little solid material. “If you
look at a tumbleweed,” he says, “you see that itâ€™s almost
all surface. Thereâ€™s not very much meat; itâ€™s almost all bone.”
He decided to try to make a glass-based material that was just as open, or
porous, but on an extremely tiny scale, the molecular level.
Brinker, who now keeps a big tumbleweed hanging from his office ceiling, came
up with a “tumbleweed in a beaker”--an extremely thin, honeycomb-like
film. Like tumbleweed, the film is made up almost entirely of pores. Brinker
refers to the filmâ€™s pores as “nanopores” because their
diameter is only a few nanometers, the size of several atoms.
The new filmâ€™s nanopores are not only incredibly tiny, but very close
together--which means that they can trap and concentrate gas molecules very
easily. At Sandiaâ€™s
Center for Integrated Nanotechnologies, director Terry
Michalske saw that Brinkerâ€™s nanoporous film could become the heart
of a new, more efficient sensor. According to Michalske, soldiers in the field
during the 1991 Gulf War were equipped with sensors that tended to sound an
alert “every time someone lit a cigarette or fired up a diesel engine.”
On battlefields and at home, sensors had to be very sensitive, but also extremely
discriminating, alerting their users only to real threats.
At the center that Michalske oversees, Brinkerâ€™s film was incorporated
into a brand new sensor no larger than a cell phone. These sensors are now
in domestic airports and subway train stations, though their exact locations
are secret. In relatively confined spaces, like station corridors or airport
security checkpoints, where the air is more concentrated, the new sensor can
pick up all gases exuding from clothing, suitcases or backpacks. Inside the
sensor, gas molecules collect in the filmâ€™s nanopores. Under the film,
a metal strip heats up, releasing the molecules into a miniature detector
for instantaneous analysis. The whole process can tell whether a traveler
is carrying something dangerous in less than a second.
Overseas, Brinkerâ€™s inspiration from tumbleweed has rolled into the current
Gulf War. According to Michalske, sensors that carry Brinkerâ€™s film
are also flying on drones in Iraq, on the lookout for chemical weapons.
work, which has been published in the journals Nature and Science, was supported
by the National Science Foundation, the Department of Energy, and the Defense
Advanced Research Projects Agency.