Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, August 11, 1993 TAG: 9308110236
SECTION: CURRENT PAGE: NRV-1 EDITION: NEW RIVER VALLEY
SOURCE: MADELYN ROSENBERG STAFF WRITER
DATELINE: BLACKSBURG LENGTH: Medium
Foam. Rubber. The kind that expand. The kind that don't.
All told, this professor of industrial and systems engineering has about 30,000 samples.
As director of Tech's Auditory Systems Laboratory, he receives the latest ear-protection devices on the market.
He analyzes them in his lab to see how well they protect the ears, and if workers receive adequate protection when the devices are used under real conditions.
Some packages promise to knock out up to 35 decibels, the equivalent of a quiet speaking voice, Casali said. But that's based on a perfect fit, and how many one-size-fits-all plugs fit the ear perfectly?
He has worked on a form-fitting ear plug of his own, though, along with graduate student Daniel Mauney, that recently received a U.S. patent.
Casali hopes to find a company that will help him create it.
The plug uses a foaming material that fills the outer part of the ear canal, creating a custom fit.
People have seen blurbs on the plug in papers and journals.
"We've already received a fair amount of letters," said Mauney, who is to receive a doctorate in human factors engineering in December.
"Regular people call to say they're light sleepers and they want the ear plugs. . . . They don't realize they're still in the development stage."
At factories, he says, other students already have come back with a list of people willing to be guinea pigs.
"I've always been interested in human perception and also in safety," said Casali. "I wanted to work on problems that affected a lot of individuals."
About nine million American workers are exposed to hazardous noise levels.
That's not counting the people who go to loud rock concerts, speedways or shooting ranges.
In another research project at Casali's Tech lab in Whittemore Hall, graduate students have been taking molds of 600 ears for a project they're conducting to make headsets more effective.
They've listened to tapes made inside the cab of a Volvo GM truck to see whether a synthesized voice would be an effective communicator among the chatter of a radio and the roar of a road. (Probably, it wouldn't.)
And they've studied communications devices, making sure they can be heard above a roar of a cockpit or traffic jam.
They've used human subjects and, when the noise levels grew dangerous, a mannequin named KEMAR inside the chambers of the fifth-floor laboratory.
They work outside of the lab, too. And these assignments in the community attracted him to his specialized field.
He helped the city of Princeton, W.Va., draft a noise ordinance and taught police officers how to enforce it.
And he's done hearing conservation studies at factories, such as Bluefield's WoodTech.
Casali was in the factory until midnight in November, checking the changing noise levels at the plant, which produces laminated veneer lumber.
Sometimes, fixing a valve or tuning a muffler could make a hearing environment safer, he said.
"He helped us pinpoint the types of noises that would bring the level down," said Randy Wyatt, safety and environmental officer for WoodTech. "We'd hear a hissing noise, and we wouldn't think it would be damaging. You'll hear a noise daily and you won't think it's a bad noise, but it is."
Casali's interest in ear research takes him into many different settings.
On a recent Wednesday, Casali wore a gray suit and a stylish print tie - not attire you'd see at a monster truck show.
But he went to one at the Roanoke Civic Center, armed with a sound-level meter.
Casali figures people are attracted to the noise - 100 decibels and up - and the power it reflects. But it's dangerous, he said, it could damage hearing permanently.
"Not many people there had hearing protection on," he said. "We brought our ear plugs."
He wrote his only letter to the editor on the subject.
Most of his other work appears in journals, or goes straight to the ears of factory foreman, with advice for those who will listen.
\ DECIBEL LEVELS OF SOME COMMON NOISES\ \ Whisper 10 to 15 decibels\ \ Normal conversation 50 to 60 decibels\ \ Lawn mower (with a muffler) 80 to 90 decibels\ \ Small jet airplane at takeoff 110 to 120 decibels
by CNB