
Cotton Quality Prediction on a New, Improved
WavelengthBy Jill Lee January 8, 1997High volume instrumentation (HVI) is the cotton industrys standard
tool for determining the length, strength and natural color of cotton. Adding
another process--called near-infrared spectroscopy--can reveal bulk maturity, a
characteristic thats key to how well the cotton will take dye, a
U.S. Department of Agriculture researcher
says. Near-infrared spectroscopy (NIR) uses light wavelengths that humans
cant see to detect otherwise invisible fiber qualities, said
chemist Joe Montalvo. Hes at the
Southern Regional
Research Center operated in New Orleans by USDAs
Agricultural Research Service. The NIR simultaneously measures the fibers cell wall thickness and its
perimeter, Montalvo said. This data is fed into a computer programmed to
calculate the fibers dyeability and maturity. The information generated
by the computer can help mills determine what products can be made from that
particular fiber and how well it will take dye. "Earlier tries at making NIR a part of HVI left users wanting more
speed and greater accuracy, Montalvo said. We feel weve met
and exceeded those demands through extensive scientific fine-tuning. Dye imperfections cost the U.S. cotton industry approximately $200 million
annually. Since the cotton industry cant completely prevent poor-dyeing
fiber from getting into mills, fabric makers typically discover dyeing
imperfections too late and must resign themselves to selling the cloth at a
loss. NIR-enhanced HVI wont solve all fiber quality problems outright,
but it could be an important prediction tool for mills and growers, said
Montalvo. Thats why we encourage our colleagues in the cotton
research community to look at what weve done and see if they agree with
our findings. In the new HVI model, a mechanical arm pushes a larger cotton sample--about
five inches in diameter--against a bigger glass plate where light waves shoot
through the fiber. Previously, samples were about the size of a quarter. The
bigger sample helps reduce measurement errors. Improvements in the
spectrophotometer, the device that produces and measures the light waves, have
cut sample reading time from 30 seconds to one second. Montalvo collaborated with teams of statisticians in government and private
industry to develop appropriate mathematical treatments for analyzing NIR data.
More than 200 cotton samples were used to develop the equations. In tests, the
improved NIR analysis showed less than 2 percent error in its ability to
predict maturity. Scientific contact: Joe Montalvo, Fiber Physics
and Biochemistry Research, Southern Regional Research Center, Agricultural
Research Service, USDA, New Orleans, La. 70179. Telephone (504) 286-4249; fax
(504) 286-4419 U.S. Department of Agriculture | |