Shuttle foam, dolphin drumming, chorus singing


Acoustics meeting in Minneapolis to feature diverse topics

Melville, New York, September 13, 2005---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.

The Acoustical Society of America ( 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.

We encourage you to visit ASA's "World Wide Press Room" (located at 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.

Reporters covering the meeting can receive a complimentary press badge to attend all sessions. Please fill out the reply form if you are interested in attending the meeting and/or receiving a copy of the book of abstracts. For media inquiries during the meeting, please feel free to contact Ben Stein ([email protected], 301-209-3091), who will be available to facilitate your requests, from contacting speakers at the meeting to obtaining background material on meeting topics.

At 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. Information on how to enter next year's science writing award can be obtained by contacting Ben Stein at [email protected].

On 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.

Full abstracts of the presentations mentioned in this news release can be viewed at the Meeting Abstracts Database ( 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.

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

Similar-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 ([email protected]) 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)

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 ([email protected]) 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)

Conventional 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 ([email protected]), 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

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 ([email protected]) 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)

By focusing powerful ultrasound waves at specific tissue inside the body, high-intensity focused ultrasound (HIFU) now performs a growing range of medical tasks, from breaking up kidney stones to destroying certain kinds of tumors such as those in the liver and prostate. HIFU creates bubbles in and around the targeted tissue and the bubbles are closely involved in destroying the desired tissue. But the mechanics of the bubbles are still a hot topic of investigation. The bubbles, though sometimes unpredictable, can help to identify the treated area before much heating takes place, or could be used to activate drugs at specific parts of the body, but are also thought to pose the risk of releasing cancerous cells into the bloodstream. Until now, scientists assumed that the bubbles could only come from long exposure to HIFU. But now, some results (2aBB2; Larry Crum, University of Washington, Seattle; [email protected]) show that short pulses of HIFU can make the bubbles appear--even though the short bursts shouldn't make the tissue hot enough to bubble (and indeed, the results showed that the temperature rose only a few degrees). The authors present a hypothesis for why the bubbles occur. Researchers are also finding that the bubbles can also protect nearby areas not targeted by HIFU, and that bubbles in typical conditions produce only minimal tissue damage, in the form of capillary rupture in an area of approximately 0.5 mm around the focus of the HIFU beam (2pBB2; Shahram Vaezy, University of Washington, Seattle; [email protected]).

For centuries, boy choristers have been singing the uppermost (treble) registers in English cathedral music. Only in 1991 were girls first allowed to sing in these groups. Since then, a controversy has ensued over whether the inclusion of girls has altered the sound of English cathedral music. In a new series of experiments, David Howard of the University of York has explored whether listeners can actually tell the difference between girls and boys singing the top lines in these choirs. In a first experiment, Howard and his colleagues found that a group of 189 listeners could distinguish between boy and girl choristers, but attributed this ability to the fact that the two groups were singing different repertoires which highlighted their vocal dissimilarities. In a second experiment, when boys and girls sang the same repertoire, a group of 170 volunteer listeners correctly told the difference only 52% of the time, indicating that they were making guesses. Howard will also present his most recent work, in which he examines differences in the ways that boys and girls actually produce sound in the context of English choral music. (4aMU1)

Studying acoustic communication in animals is shedding new light on their "cognitive" or mental processes, which include learning, remembering, and problem-solving. Jon Grinnell of Gustavus Adolphus College in Minnesota ([email protected]) and his colleagues will explain how African lions eavesdrop on the vocalizations of spotted hyenas to locate and scavenge hyena kills. The researchers' field studies suggest that lions have the ability to remember the sounds of spotted hyenas even 10 years after their last contact with them (2aAB4). Heidi Harley of New College of Florida ([email protected]) will present evidence showing that a bottlenose dolphin learned to produce six different rhythms using a pneumatic switch that activated computer tones. As the dolphin was learning to play the rhythms, he spontaneously began to vocalize the rhythms and was trained to produce all of them vocally as well (2pAB5). Christopher Sturdy of the University of Alberta will explain how songbirds rapidly sort the vocalizations of other birds into biologically relevant categories that can represent, for example, the voices of friends and foes; songbirds are one of only six animal groups (including humans) that are known to learn their species-typical vocalizations from a tutor (adults who teach them the sounds). They represent an excellent model system to understand vocal categorization and communication (2aAB2; also see Other papers in sessions 2aAB and 2pAB contain examples of acoustically related cognition in such creatures as bats, sea lions, chimpanzees, frogs, and elephant seals.

Add ultrasound to the growing list of medical therapies that can now be monitored in real-time by high-quality images. Magnetic resonance images are useful because they can take the temperature of the tissue in a series of images, to help decide when the target areas are effectively treated, and to make sure that the areas not being treated aren't getting too much heat. One paper presents experiences with MRI while treating uterine fibroids with high-intensity focused ultrasound (HIFU) (2aBB6; Nathan McDannold, Brigham and Women's Hospital, Boston; [email protected]). In HIFU therapy of tumors, MRI can measure temperatures inside and outside the body during treatment, a French team shows (2aBB7; Rares Salomir, INSERM, Lyon; [email protected]). Other teams are developing ultrasound-guided images that may be simpler and less expensive than MRI methods. Clean maps of temperature can be taken by ultrasound throughout the treatment and afterwards as the tissue cools down (2aBB4; Peter Kaczkowski, University of Washington, Seattle; [email protected]). Studying image-guided HIFU treatment of liver and kidney tumors, another group (2aBB1; Gail ter Haar, Royal Marsden Hospital, Surrey, UK; [email protected]) has elucidated relationships between (1) HIFU-induced heat-death in cancerous tissue and (2) changes in accompanying gray-scale ultrasound images that monitor the treatment.

Session 3aNS tackles the subject of hospital noise. According to session chairs Ilene Busch-Vishniac ([email protected]) and Jim West ([email protected]) 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.

At two sessions (4aMU and 4pMU), researchers will present new discoveries and insights into the fascinating phenomenon of choir sound, the music of many singers blending in harmony. According to acoustician Harald Jers ([email protected]), important aspects of choral sound have not been researched in detail: this includes what he calls the "chorus effect," in which one loses the ability to pinpoint individual voices in a chorus, perhaps due to a complex interaction between the singers. Recording individual singers in 16-person amateur and professional choirs and measuring acoustical properties in them, Jers found differences between the amateur and professional choirs which suggested new ideas for choir rehearsals and concert performances (4aMU1). James Daugherty of the University of Kansas ([email protected]) will show how the formation of choir singers and the space between individual speakers influences how accurately individual choir singers hit a desired note and how well the choir singers were in tune with one another (4aMU2). Joao Soeiro de Carvalho of the New University of Lisbon in Portugal ([email protected]) will discuss the Subsaharan style of choir singing, which includes improvisation and a nonverbal expressive mode called the "kulungwani," which involves the tongue and parts of the jaw to produce periodic interruptions in vocal delivery (4pMU1). Ron Freiheit of Minnesota-based Wenger Corporation ([email protected]) will describe the world's first anechoic choir recording, in which the St. Olaf College (MN) choir sang inside a 3M research chamber designed to eliminate all echoes and acoustical reflections. By feeding the recording into computer simulations of acoustical spaces, designers of music halls and worship spaces can test and refine room acoustics before those spaces are even built. (4pMU3)

Performance artist Laurie Anderson said, "Writing about music is like dancing about architecture." Searching for a favorite song nowadays involves a similar kind of dance-typing in words in a computer. Researchers at session 5aMU will describe progress in designing new kinds of music-search tools, including those in which a user hums the tune of interest. Towards these ends, Anssi P. Klapuri of Tampere University of Technology in Finland (k[email protected]) will describe a method for automatically retrieving the dominant melody in complex music signals (5aMU7). Norman H. Adams of the University of Michigan ([email protected]) will describe efforts to determine the best way to convert a sung query into a representation that is most useful for music database retrieval and classification. Other talks (5aMU2, 5aMU3) will cover efforts to build comprehensive and helpful music databases and retrieval tools. Jurgen Herre of the Fraunhofer Institute for Integrated Circuits in Germany ([email protected]) will discuss MPEG-7, a new multimedia-file standard that aims to contain useful information on audio content for music search retrieval (5aMU1).

Manufacturers such as Apple Computer and Motorola have just announced mobile phones that can perform simple functions such as downloading and playing back music. But researchers are already testing more sophisticated possibilities for combining cell phone conversations with music. Masataka Goto of the National Institute of Advanced Industrial Science and Technology in Japan ([email protected]) will present hands-free music information retrieval systems that enable a user to retrieve and play back a musical piece by saying its title or the artist's name. One system works on a cell phone; by saying the title of a song, the user can retrieve the desired music so that it can be heard by everyone in a phone conversation. The other system, currently intended for desktops and kiosks, helps a user find a song even when he or she does not remember a part of its title. (5aMU4; video clips demonstrating the systems are at

To reduce the road noise which pervades our streets and invades our homes, engineers have traditionally constructed highway barriers to block out the noise; or they have attempted to cut down noise arising from cars themselves. But an alternative method is gaining traction: the use of rubber-based roadtops to quiet down the sound of tires rolling over pavement. Paul Donavan of Illingworth & Rodkin, a California-based acoustical engineering firm, will present an overview of the Arizona Quiet Pavement Pilot Program (2aNCa1). Supported in part by the US Federal Highway Administration (FHWA), the project includes a 3-year, $34 million resurfacing of 115 miles of Phoenix-area highways with rubberized asphalt, which consists of normal asphalt mixed with ground-up, used rubber tires. Illingworth & Rodkin's James Reyff will present the first-year results of the program: the engineers measured more than a tenfold reduction in traffic noise that would be heard by a typical listener from the roadside. (2pNCa5). Christopher Corbisier of the US FHWA will discuss a recently developed "Roadmap to Quieter Highways," which aims to study the quiet-pavement approach further (2pNCa1). Larry Scofield of the American Concrete Pavement Association ([email protected]) will describe the development and evolution of the various types of concrete surfaces used in US roadways from the late 1800s to the present day (2pNCa7).

Marching bands and pep bands produce music that carries great distances and results in high sound pressure levels near individual members. In what may be the first study of noise exposure for these particular activities, Joseph Keefe of Ostergaard Acoustical Consultants ([email protected]) has found that the noise exposure for these band members greatly exceeds safe values both indoors and outdoors. For typical situations, he reports, the sound dose to marching- and pep-band members ranges from 11% to 295% of the Occupational Safety & Health Administration's recommended exposure limit (REL), and from 35% to 3055% of the permissible exposure limit (PEL) defined by National Institute for Occupational Safety and Health (in both cases, 100% represents the maximum daily dose that is considered healthy). According to Keefe, "Exposures that would be considered hazardous in the workplace are common in marching and pep bands." "Students and band directors," he says, "should take steps to recognize the risk posed by various instruments and various locations," and implement efforts to protect hearing (3pNS2) In a study of the noise exposure levels for workers operating various kinds of heavy construction equipment, Ellsworth R. Spencer of NIOSH ([email protected]) will report that bulldozer operators consistently had the highest noise exposures, ranging from a NIOSH REL dose of 844% to 25,836% and an OSHA PEL dose of 139% to 1397% (3aNCe6).

In 2003, a deadly fire killed 100 people in an overcrowded Rhode Island nightclub, when a band's pyrotechnic display ignited egg-crate-like acoustical materials known as open-cell foam. Used improperly on the stage and ceilings in a misguided attempt to prevent sound from escaping the nightclub, the combustible foam caused the fire to progress rapidly and release opaque smoke, which contributed to the inability of some of the patrons to escape the fire. Acoustical consultant Klaus Kleinschmidt ([email protected]) will provide suggestions for limiting the use of such materials in assembly and meeting spaces and to use acoustical materials to reduce reverberation but not to insulate sound (3aAA2).

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 ([email protected]) 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 ([email protected]), 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 ([email protected]) 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 ([email protected]) 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).

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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