Microwave Scale Takes a
By Jill Lee
August 18, 1997
Need to know the mass of an object that is literally too hot to handle? A
new device originally designed to measure corn kernel moisture could prove
useful in manufacturing because it can measure the mass of objects dangerous to
touch, such as molten ceramics or glass.
Developed by engineers Andrzej Kraszewski and Stuart Nelson with
Agricultural Research Service, the
instrument uses microwaves to accurately measure grains moisture content
without harming the seeds. The device also works on peanuts and soybeans.
The seed moisture measurements are part of a larger effort to protect food
quality. Moisture gives a foothold to the fungus Aspergillus flavus,
which produces aflatoxin, a dangerous food contaminant. Keeping seed moisture
low during storage reduces the risk of A. flavus contamination.
Kraszewski and Nelsons invention is based on something called a
microwave resonant cavity. The microwave resonant cavity measures the
disturbance an object creates as it moves through a microwave field. Based on
these measurements, the researchers new device calculates mass and
moisture content and reveals defects without harming the measured object.
The scale is fast, taking a measurement in as little as 20 milliseconds.
Best of all, it can be manufactured with readily obtained components,
researchers said. They received a
(# 555-4935) on the technology and it is available for license.
Scientific contact: Stuart O. Nelson, USDA, ARS,
Center, Athens, Ga. Phone: (706) 546-3101; fax (706) 546-3607, e-mail: