sealPurdue Science, Engineering, Health Briefs

September 1999

New institute to begin research into quiet highways

WEST LAFAYETTE, Ind. -- Engineers at Purdue University have formed the first center in the nation dedicated to understanding the precise physics behind highway noise, a prerequisite for reducing the nuisance.

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The numerous buffers installed between freeways and residential neighborhoods attest to the problem, says Bob Bernhard, director of the new Institute of Safe, Quiet and Durable Highways, which was dedicated Aug. 27.

"Residents rarely complain about being able to see a highway, but they often complain about highway noise," he says, noting that barriers built to wall out the road racket can cost as much as $1 million per mile.

Bernhard says most of the acoustical pollution from cars doesn't come from engine noise but from the interface of tires and road surfaces. Engineers suspect that several mechanisms are to blame, including:

  • Air that is trapped and compressed between a tire's tread pattern and the road surface eventually bursts from the confining spaces, causing pops and whistles.

  • Block-like shapes in the tread design that smack against the road surface like tiny hammers.

  • Those tread blocks and underlying belts vibrate and radiate energy outward, producing sound much like the vibrating cones in stereo speakers.

Purdue engineers propose to attack the problem by studying both tires and road surfaces. The results will then be used to design tires and road surfaces that make less noise.

Research will include the use of lasers and sound waves to analyze noise-producing mechanisms in rotating tires. Engineers will study porous pavements that have been used in Europe to build quieter roads.

The institute is a joint project of Purdue's schools of civil and mechanical engineering in collaboration with researchers from the Pennsylvania Transportation Institute at Penn State University, where researchers will make a database of sound produced by transit buses in efforts to reduce bus-related noise pollution, he says.

The institute is funded by a $3.6 million grant from the U.S. Department of Transportation and an equal amount from other government and private sources. It will expand later to include research dealing with other sources of transportation-related noise, such as truck engines, as well as issues involving highway safety and durability, Bernhard says.

CONTACT: Bernhard, (765) 494-2141;

Purdue expert: Take your calcium throughout the day

WEST LAFAYETTE, Ind. -- Keeping track of your daily calcium intake may not be enough to ensure that your body absorbs adequate amounts to prevent osteoporosis, says a Purdue University expert.

Connie Weaver, head of Purdue's Department of Foods and Nutrition and an expert in calcium absorption, says women who take calcium supplements after a meal high in calcium-rich foods may not absorb as much as they think.

"The body is quite efficient at absorbing calcium levels up to 500 milligrams but becomes less efficient for amounts above that," Weaver says. "The best advice is to eat a calcium-rich source at every meal, and if you are using supplements, the supplement would serve as the calcium-rich source for that meal."

Intake recommendations for calcium are 1,000 milligrams a day, or about three servings of milk, for adults under 50, and 1,200 milligrams a day for adults over 50 to help counteract bone loss due to aging. For children, the daily intake recommendations are 800 milligrams for ages 6-8 and 1,300 milligrams, or about four servings of milk, for youngsters ages 9-18.

CONTACT: Weaver; (765) 494-8231;

Purdue astronauts to rendezvous on campus Oct. 22

NOTE TO JOURNALISTS: A news conference is being planned, time and date to be announced, and that will be the only time during the weekend that journalists will have access to the astronauts.

WEST LAFAYETTE, Ind. -- Most of Purdue University's 19 living astronaut alumni will return to their alma mater for a reunion this fall.

Neil Armstrong and Eugene Cernan, the first and last men on the moon, are expected to join other astronaut alumni who will return to campus for President's Council Weekend, Oct. 22-23. Planning is still under way, but many of the astronauts will speak at various "Back to Class" sessions offered to President's Council members that Friday, and all will be honored at halftime of the Purdue vs. Penn State football game that Saturday.

Purdue, known as the cradle of astronauts, has graduated 21 people who have been selected for space flight, including Virgil "Gus" Grissom and Roger Chaffee, who died Jan. 27, 1967, in a fire inside their space capsule during a preflight test of Apollo 1. The "Purdue in Space" Web page has more information about the university's astronaut alumni and about space research at Purdue.

The President's Council is an organization of individuals and families who provide significant financial support to the university.

CONTACT: Greg Zawisza, director of special projects for the Office of University Relations, (765) 494-2086; greg_zawisza@uns.purdue

Compiled by Susan Gaidos, (765) 494-2081;

Purdue News Service: (765) 494-2096;


Jacob Klos, left, a Purdue graduate student in mechanical engineering, and Bob Bernhard, an engineering professor and director of the university's Institute of Safe, Quiet and Durable Highways, use a laser to study how noise is generated by a smooth tire on a textured surface. The tire, painted white to better reflect laser light, is rotated on a motor-driven roller. The laser measures vibration. (Purdue News Service Photo by David Umberger)
A publication-quality color photo is available at the News Service Web site and at the ftp site. Photo ID: Bernhard.roads

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