Blue Jean Physics

     WHETHER YOU'RE A BRONC BUSTER OR A BUS DRIVER, EVERYONE HAS A FAVORITE PAIR
OF BLUE JEANS.  BUT THEY'RE MORE THAN JUST COMFORTABLE; JEANS ARE AN INTEGRAL PART OF
AMERICA'S TEXTILE INDUSTRY, ONE OF THE MOST IMPORTANT INDUSTRIES IN THE COUNTRY.  TO
STAY FIT AND TRIM MANY COMPANIES ARE AUTOMATING THEIR FACTORIES, BUT THAT'S NOT SO
EASY WHEN WORKING WITH DENIM, SAYS PHYSICIST KIMBERLY TITUS AT NORTH CAROLINA STATE
UNIVERSITY.  

     Titus: "When you are dealing with something that is as limp and deformable as fabric, it's almost too
easy to assume that the next panel is going to be exactly where you expect it to be . . . you need a way to insure
that. . .the panel is aligned . . . because any discrepancy . . .is going to cause problems downstream. " 

     TO MAKE SURE THAT A STITCH IN TIME WILL SAVE NINE TITUS WORKS WITH JEAN
COMPANIES TO BUILD SENSORS THAT CATCH MISTAKES BEFORE THEY HAPPEN.  SIDE SEAMS, FOR
EXAMPLE, INVOLVE A PARTICULARLY TRICKY BIT OF SEWING WITH  FOUR LAYERS OF FABRIC,
TIGHTLY BOUND TOGETHER.  ON THINNER FABRICS SENSORS WORK BY SHINING LIGHT THROUGH
THE SEAM. BY MEASURING HOW MUCH LIGHT ACTUALLY MAKES IT THROUGH YOU CAN TELL HOW
THICK THE SEAM IS, IN OTHER WORDS WHETHER THERE ACTUALLY ARE FOUR LAYERS INSTEAD OF
TWO OR THREE.  BUT DENIM IS SO THICK THAT NOT MUCH LIGHT CAN MAKE IT THROUGH THE
SEAM.  AFTER A YEAR OF HARD WORK, TITUS THINKS SHE MAY HAVE OVERCOME THIS PROBLEM
WITH A NEW SENSOR THAT CAN TEST THE SEAMS BEFORE THEY GET BANGED UP WHEN
STONEWASHED. 

     Titus: "I've seen stonewashed jeans that have holes where the seams should be just because once little
bit of an edge slips out."

     OF COURSE, THERE ARE PROBABLY SOME PEOPLE OUT THERE WHO'D RATHER HAVE THE
JEANS WITH THE HOLES, BUT FOR EVERYONE ELSE, THE SENSOR SHOULD HELP KEEP THE JEANS,
AND THE TEXTILE BUSINESS, STRONG.