“no more lines. You just walk out with your stuff.” —JAMES M. TOUR
Bar codes may
check out next
By Lisa Grossman
Grocery checkout lines might become as
obsolete as milkmen if a new tag meant
to replace bar codes becomes common.
Researchers from Sunchon National
University in Suncheon, South Korea,
and Rice University in Houston have
built a radio frequency identification
tag that can be printed directly on cereal
boxes and potato chip bags. The ink itself
would broadcast information about each
item in a grocery cart.
“You could run your cart by a detector and it tells you instantly what’s in the
cart,” says James M. Tour of Rice University, whose research group invented
Putting printable radio frequency iden-
tification devices in packaging could
take the wait out of grocery shopping.
the ink. “No more lines. You just walk out
with your stuff.”
RFID tags are already used in pass-
ports, library books and gadgets that let
drivers pay tolls without stopping. But
those tags are made from silicon, which is
more expensive than paper and has to be
stuck onto the product as a second step.
The new tag, reported in the March
IEEE Transactions on Electron Devices,
costs about three cents compared with
about 50 cents for each silicon-based tag.
The team hopes to bring that cost below
one cent per tag to make the devices
belong in jewelry
Perovskite outdoes platinum
in cleansing diesel exhaust
By Alexandra Witze
Chemical engineers have found a cheaper
and possibly better material than platinum for cleaning up diesel exhaust.
Many automobiles use platinum-containing catalytic converters to help
clean exhaust streams of pollutants, notably the nitrogen oxide compounds that
can contribute to smog. But the high and
volatile price of the precious metal makes
it difficult to build an economical catalyst.
A material known as perovskite is far
less expensive than platinum and may do
the job more effectively, engineers from
the research arm of General Motors
report in the March 26 Science.
“It’s excellent work, really ground-
breaking to be able to have an alterna-
tive to platinum-based catalysts,” says
Louise Olsson, a catalysis researcher at
Chalmers University of Technology in
Göteborg, Sweden. “It’s going to save a
lot of money.”
Research and Development branch in
Warren, Mich., focused on a chemical
reaction in diesel exhaust streams that
converts NO to NO2, which can then be
further processed and released to the
atmosphere as nitrogen gas.