Acoustics News -- Multimedia

Newswise — What acoustic information can bacteria generate to help workers monitor the performance of waste-management equipment? How many people do airplanes wake up every night when they fly over residential neighborhoods? How different must two drug names sound to prevent doctors and patients from getting confused over them?

These and other questions will be addressed at the joint meeting of the Acoustical Society of America (ASA) and NOISE-CON 2005, the annual conference of the Institute of Noise Control Engineering. The meeting will be held October 17-21, 2005 at the Hilton Minneapolis Hotel (1001 Marquette Avenue, Minneapolis, MN 55403). Over 770 papers will be presented. Scientific papers on these news items and more, written in a lay language style, are available at http://www.acoustics.org/press .

The Acoustical Society of America (http://asa.aip.org) is the largest scientific organization in the United States devoted to acoustics, the science of sound. The Institute of Noise Control Engineering of the USA (INCE/USA) is a non-profit professional organization with the primary purpose of promoting engineering solutions to environmental noise problems.

WORLD WIDE PRESS ROOMWe encourage you to visit ASA's "World Wide Press Room" (located at http://www.acoustics.org/press) before and during the meeting. By the week of October 2, the site will contain lay-language versions of selected meeting papers. These papers will enable you to cover the meeting, even if you can't leave your desk.

ASA SCIENCE WRITING AWARDAt a plenary session on Wednesday, October 19, ASA will present its 2005 Science Writing Awards in Acoustics for Journalists to Declan Butler of Nature Magazine for his piece "Sound and Vision" published in Nature on 5 February 2004 and to Kate Ramsayer for "Infrasonic Symphony" published in Science News on 10 January 2004.

PUBLIC CONCERT SHOWCASES CHOIR ACOUSTICSOn Thursday, October 20, at approximately 4 p.m., a short choral performance, open to the public, will feature the 90-voice St. Olaf Cantorei from St. Olaf College in Northfield, MN. To take place at the Central Lutheran Church in Minneapolis (333 South 12th Street), the performance is open to the public. The choir will be accompanied by organ, brass quartet, handbells, and percussion. The performance will feature a hymnsing in which the audience will be invited to participate. It will be preceded by a panel discussion on acoustical issues relevant to choral singing.

VIEWING MEETING ABSTRACTSFull abstracts of the presentations mentioned in this news release can be viewed at the Meeting Abstracts Database (http://asa.aip.org/asasearch.html) by typing in the last name of the author or the appropriate paper code. Entire sessions can be viewed by simply typing in the session code followed by a star (e.g., 1aBB*). In addition, typing a general subject (such as "chorus") or a particular university or state (such as "MN") may provide other results of interest.

PROGRAM HIGHLIGHTSThe following items describe some highlights from among the many papers being given at the meeting.

MAKING DRUG NAMES LESS CONFUSINGSimilar-sounding drug names, such as Celebrex and Cerebyx, pose the risk of creating medical prescription errors for patients, doctors, or pharmacists who mishear or misremember them. B. L. Lambert of the University of Illinois at Chicago and his colleagues are studying the auditory perception of 200 drug names by pharmacists, physicians, nurses, and laypersons. The researchers played recordings of the drug names in various acoustical conditions, including those simulating the audio quality of telephone calls, and amidst the background cacophony of 20 other people engaged in conversation such as in a busy hospital. The results will be used to help drug companies and regulators develop more distinct product names that could be differentiated from other drugs in noisy or low-audio-quality conditions. (3aNS3)

SHUTTLE FOAM GLUED ON PROPERLY? SOUND CAN TELL Researchers will report the latest developments on a promising acoustic tool to identify flaws in the spray-on foam used to insulate the external fuel tank of the space shuttle. In the 2003 shuttle disaster, experts implicated shuttle foam as the cause; video showed that the insulation foam broke off and hit Columbia's left wing, causing damage which experts believe led to the disintegration of the shuttle during its re-entry. A one-pound slab of foam also broke off during the July 26 liftoff of the shuttle Discovery, but fortunately did not hit the spacecraft. In a recent experiment, Todd Thompson and J. Adin Mann III of Iowa State University placed an acrylic tube on a sample NASA spray-on foam. The sample contained areas where the the foam was intentionally disbonded, or unglued, from the metal. By broadcasting sound through the tube onto the foam, they found that the disbonded regions absorbed more sound in the frequency range between 1000 and 4000 Hz (specifically, the absorption peaks for disbonded were 25-50% higher for those of properly bonded foam). The researchers were able to use their acoustic measurements to determine the size and location of the bonding defects. The researchers' next steps are to further develop this tool as a non-invasive and reliable means for inspecting shuttle foam before liftoff in future shuttle missions. (1pNCd1)

EXTINGUISHING FIRE WITH SOUND WAVESConventional fire extinguishers do not work properly aboard spacecraft, because the extinguisher's foam tends to spread out in a low-g environment rather than smother a fire. Therefore, students from the University of West Georgia are testing to see if sound waves can extinguish a flame in a low-gravity environment. Dmitriy Plaks, an undergraduate member of the entirely student-run "Prometheus Project," will describe the group's experimental apparatus, which is scheduled to fly next year in a low-g environment aboard a NASA C-9B Aircraft. In the meantime, the Prometheus Project, which contains graduate-student and faculty advisors, has obtained an encouraging sign: sound can repeatedly extinguish small flames in the 1-g environment of their lab. This finding might lead to applications of its own, such as putting out fires in computer-server rooms where water damage from conventional fire extinguishers can be costly. Using sound to extinguish flames is new and has not been previously reported in the literature, according to Plaks. While the researchers know that sound can cause pressure to drop at the site of a flame, they are working to determine the explicit mechanism, which might involve a temperature decline at the site of the flame or a decrease in the concentration of oxygen (3aEA10; more information at http://www.westga.edu/~rgsfop).

LISTENING TO BACTERIA BREAK DOWN WASTE Waste-management facilities rely upon machines called "digesters," which employ anaerobic bacteria to break down organic waste. In order to help monitor and improve the digesters at these industrial facilities, and develop a more precise understanding of bacterial metabolism, Miguel Horta and Steve Garrett at Penn State have designed a sonic gas sensor that can detect the amount of hydrogen or methane that bacteria produce when they break down organic compounds. In the setup, a small loudspeaker creates a sound wave inside a pair of open tubes through which the gas produced by the bacteria is flowing. As the bacteria generate gas, the changing gas concentration alters the acoustic resonance frequency in the tubes. Microphones connected to specialized electronics track and record this resonance frequency that precisely determines the change in concentration of the waste gas. The researchers hope that acoustics will provide a valuable tool for real-time monitoring of digester performance, improving bio-energy production from organic wastes, and conducting studies of bacteria's metabolic rates. (3aEA9)

WHY ARE HOSPITALS GETTING NOISIER AND NOISIER?Session 3aNS tackles the subject of hospital noise. According to session chairs Ilene Busch-Vishniac and Jim West of Johns Hopkins, hospital noise is an under-researched problem and little is known about its effects on patients and doctors as well as healing and safety. Overall, since 1960, average hospital noise levels appear to be increasing 0.38 decibels per year during daytime hours and 0.42 during the night, point out West and Busch-Vishniac, who will present an overview of the issue in paper 3aNCa1 as well as new measurements which confirm this trend.

HOW MANY PEOPLE WILL AIRPLANES WAKE UP AT NIGHT? In efforts to determine acceptable noise levels for aircraft flying over residential areas during the night, researchers have typically determined when the "average person" would be awakened by the sound of a single airplane as heard in a bedroom. Acoustical consultants Grant Anderson and Nicholas Miller of Harris Miller Miller & Hanson, Inc. will present a more sophisticated re-analysis of aircraft noise and awakening data, in order to account for the effects of multiple aircraft flying throughout the night, as well as the personal variations in the amount of noise needed to awaken an individual (2aNCd4). According to consultant Paul Schomer, traditional "dose-response" assumptions about the amount of aircraft noise needed to annoy community members underestimate the actual numbers of individuals highly annoyed by aircraft flyovers by as much as a factor of four in some cases (1pNS7). Carl Burleson of the Federal Aviation Administration will present the Next Generation Air Transportation System Plan, which aims to protect the environment while allowing for sustained aviation growth. According to Burleson, this includes reductions, in absolute terms, of community noise and local air-quality emissions from aviation that make a significant impact on human health and welfare (1aNCa1). In terms of reducing noise inside aircraft, Gopal Mathur of The Boeing Company will present a new, improved active-noise control system (which uses vibrations to cancel out noise in aircraft fuselage), based on mature technology that promises to be more practical and reliable than past active-control design efforts (3aNCb1).

These items were prepared by Ben Stein and Martha Heil in conjunction with the respective meeting presenters and the Acoustical Society of America.