bluuebunny/crossref_metadata_2025 huggingface dataset:
Heating, ventilation, and air conditioning flexible duct acoustical solutions.
Authors: Silverman Neil
Published: March 2010

Flexmaster USA has been manufacturing the highest quality flexible duct available for commercial applications for over 30 years and has a wide array of selections. There are three very distinct choices, type 6, type 8, and our Medical Grade Triple Lock Acoustical that have been tested by Energistics Laboratory, which is a research and test facility dedicated to the HVAC industry. The testing for Flexmaster USA’s type 6, SPUN BOND Nylon, type 8, chlorinated polyethylene (CPE) fabric, and model MGA TLM (aluminum corrugated flexible duct) has shown significant reduction in sound. In other words, they absorb unwanted sound, including the most important mid-range frequencies. Our products listed here will significantly reduce unwanted noise in all of your rooms. These products allows sound—not air flow—to permeate through the liner and become absorbed inside the insulation. Each 6 in. test specimen was tested both straight and with a 90 deg bend for velocities of 0 FPM, 500 FPM, and 1000 FPM and compared to hard metal duct at the same velocities. Diameters of 6 in. thru 16 in. were provided by Flexmaster USA directly to Energistics Laboratory for the testing that was concluded in July of 2006. Unique to others in the industry, Flexmaster USA manufactures flexible duct without the use of glues or adhesives. The mechanical-locked inner core maintains its shape
A physically motivated room reverberation enhancement system that is stable in any (passive) room.
Authors: Berdahl Edgar , Niemeyer Gunter , Smith III Julius O.
Published: March 2010

Prior active room reverberation enhancement systems have typically employed microphones, artificial reverberator filters, and loudspeakers to change the reverberant properties of a room. However, acoustic feedback from the loudspeakers to the microphones has had the potential to drive such systems unstable. In contrast, techniques from feedback control can be used to design a stable room reverberation enhancement system from the ground up. A feedback controller implements a passive connection between virtual acoustic spaces, which are realized using digital waveguide networks, and special transducers, which operate concurrently as microphones and loudspeakers. Because the feedback controller models a passive system, it is theoretically stable for arbitrarily large loop gains in any (passive) acoustic environment. As a consequence, the system does not suffer from “ringing tones” at high-loop gains in the same way as prior systems have suffered. Furthermore, the system does not need to be re-calibrated if the properties of the room change or even if moved to a whole new room. Finally, this method for designing room reverberation enhancement systems may generally result in more realistic reverberant sound because it implements the acoustical features of a system that could exist naturally in the physical world.
An electroacoustic sound transmission system that is stable in any (passive) acoustic environment.
Authors: Berdahl Edgar , Harris Dan , Niemeyer Gunter , Smith Julius
Published: March 2010

Active electroacoustic systems are commonly employed to transmit sound from one location to another. For example, consider the following configuration: a person talks into a microphone, which produces an electrically amplified signal for driving a loudspeaker, and the loudspeaker induces an output acoustic signal allowing someone else at a more distant location to hear the person talking. Unfortunately, such system designs typically do not consider acoustic feedback, which can destabilize the system and result in “howling.” In contrast, a feedback control system can transmit sound from one location to another using collocated microphone/loudspeaker transducers without the risk of howling. We design feedback controllers that model positive real (i.e., passive) systems, such as a spring and a gyrator. The spring controller essentially binds the diaphragms of the two transducers together. We relate the spring controller to the string connecting two tin cans together in the classical tin can telephone. Measurements are performed on a real feedback control system with two transducers. Because the feedback controller models a passive system, it is stable in any (passive) acoustic environment. [Sennheiser Electronic Corporation helped support this work.]
Retrofit structural insulated panels increase sound transmission loss of existing single family houses impacted by highway noise.
Authors: Harvey, PE Scott
Published: March 2010

Owners of newly constructed houses complained of interior noise from a nearby interstate highway. The houses were constructed using structural insulated panels (SIPs) as opposed to conventional 2x4 wood studs. The SIPs are composed of 3.5 in. of expanded polystyrene insulation sandwiched between two layers of oriented strand board (OSB) and exhibit higher thermal efficiency than conventional construction. Sound transmission loss testing of the standard SIPs, however, reveals relatively low acoustical performance especially in the 630 Hz range. This characteristic acted as a band pass filter allowing only a portion of the broadband traffic noise to enter the house. The observed traffic noise inside the house had a clear tonal quality adding to the annoyance of the traffic noise impact. After consideration of several remedial options the builder decided to retrofit the exterior of the impacted houses using a combination of standard resilient channel, insulation, and additional OSB. Some window replacements were also required. These treatments resulted in reduced interior noise levels especially in the 630 Hz range.
A simple estimation of z vibration for a Hopsca above depot by analog measurement and analysis in a metro station.
Authors: Zhang Jiping , Weng Jianxiong , Wang Lei , Jiang Yexiang
Published: March 2010

The word Hopsca means Hotel + Office + Park + Shopping mall + Convention + Apartment and was originated from La Defense in Paris of France in 1986. Metro depot is generally a parking and maintenance base and covers a large area and available land resources. It is a feasible approach to achieve comprehensive land utilization to develop top head estates above the depot by building residential, business, commercial, and recreational and sports urban functions. Such cases are well done, for example, in Hong Kong but generally few. The Metro in Hangzhou City of China is developing such a Hopsca. Because the trains will run and receive maintenance in the depot, the vibration and noise must be designed not transmitted to the top head estates. It will be very valuable to study the transmission and control of the vibration. This paper managed to estimate the complex vibration by simple analog measurement and analysis on a typical aboveground metro station with top head urban functions in Shanghai City of China.
An examination of the combined effects of loudness, tonalness, and roughness on annoyance ratings of aircraft noise.
Authors: More Shashikant , Davies Patricia
Published: March 2010

This study is part of a broader investigation into how noise characteristics other than loudness affect people’s responses to aircraft noise. In previous studies, some evidence of increase in annoyance ratings with increased tonalness and roughness was found when loudness was kept constant and only tonalness or roughness was increased. The objective of this study was to investigate the combined effects of loudness, tonalness, and roughness on annoyance ratings of aircraft noise. A simulation program was used to generate two sets of stimuli based on flyover after take-off events of an Airbus-310, a Boeing-757, and an MD-80 aircraft. For nine stimuli in Set A based on an Airbus-310 recording, both tonalness and roughness varied while loudness kept constant. The 12 stimuli in Set B are based on recordings of all three aircrafts. In this test loudness, tonalness, and roughness were all varied. Subjects rated these sounds on an annoyance scale. Most of the subjects found to be very sensitive to tonalness when both tonalness and roughness varied and loudness was kept constant. Loudness was found to be the major contributor to annoyance when loudness, tonalness, and roughness varied simultaneously but tonalness and roughness also influenced the annoyance ratings.
The need for a “green” sound of e-cars—The challenge of passung.
Authors: Schulte-Fortkamp Brigitte
Published: March 2010

The climate change is forcing to develop E-cars and also rethink how an E-car should sound. There is little agreement over what the sound should be. Some car manufactures seem to think about to make the cars more loud. But the question is how should a sound “sound” to provide the message about this ecological car? For sure there is a lack of collaboration to be filled amongst engineering and further future orientated science. Moreover, there is a clear need to get to know how the future client will accept such the new cars and how an appropriate sound will support this acceptation. Whenever the acoustical design of vehicles is under scrutiny, the crucial question about the appropriate method of evaluation arises. Many studies show that not only acoustic but also non-acoustic parameters have a major influence. Methods that give the opportunity to test the quality of the given ambience and to register the effects and evaluations in their functional interdependence as well as the influence of personal and contextual factors are needed to solve the upcoming problems to design the sounds of E-cars ecologically appropriate. This concept will be introduced.
Prediction of subjective annoyance for transient sounds using a loudness-based impulsiveness measure.
Authors: Willemsen Andrew , Rao Mohan , Wong Jasper
Published: March 2010

This paper presents a study on the characterization of the sound quality of transient sounds via fundamental psychoacoustic measures. Specifically, the overall subjective perception of annoyance for transient sounds was studied. Through magnitude estimation and paired comparison jury evaluation experiments, the subjective annoyance magnitudes of 15 transient sounds were determined. For each sound, several objective psychoacoustic measures were calculated, and using simple linear regression models, the relationships between these objective measures and the subjective annoyance magnitudes were investigated. Examined psychoacoustic measures included loudness, sharpness, roughness, fluctuation strength, tonality, and a new loudness-based measure of impulsiveness. The new impulsiveness measure is based on the summation of the magnitudes of impulse-induced peaks in the loudness time history for a sound (calculated according to DIN 45631/A1). The models were analyzed using several statistical measures of model significance and fit. It was found that for the transient sounds studied, significant relationships existed between subjective annoyance and each of the following psychoacoustic measures: loudness, sharpness, roughness, and loudness-based impulsiveness. These four measures were then combined into a single model for predicting subjective annoyance using multiple linear regression analysis. It was found that this model was highly correlated to the subjective annoyance of transient sounds.
A comparison of displacement and velocity proportional dampers for use in aircraft.
Authors: Hudik Mike , Downing Mark
Published: March 2010

Surface effect dampers have been used in aircraft to aid in the attenuation of shimmy conditions on the nose landing gear. Shimmy conditions can lead to increased cockpit noise, increased component wear on the nose landing gear, and a decrease in aircraft control during operation. Hydraulic fluid filled dampers have traditionally been used to attenuate shimmy. They are, however, susceptible to leaking. This in turn relates to a decrease in performance and ultimately an increase in maintenance cost. Surface effect dampers use metal sliding over a rubber piston to create a combination of viscoelastic and Coulomb damping. This construction is immune to leaking and offers unique performance in comparison to hydraulic. This paper provides an overview of the difference between surface effect and hydraulic dampers for shimmy attenuation. Points to be touched on will include damper principles, equations of motion, the theoretical hysteresis curve, volumetric efficiency, and observations related to product life. Part test data will be compared to theory. Furthermore, this paper will discuss the process of completing the STC for a particular aircraft, discussing both the laboratory and the on-wing testing required to show the functional characteristics are satisfied.
The effects of structural damping on the radiated noise of circular saw blades during operation.
Authors: Hufnagel Alan
Published: March 2010

Noise from circular saw blades is a common industrial noise problem. A circular saw blade using constrained layer damping technology can significantly reduce the noise emitted during the cutting process. The noise reduction benefit of a constrained layer blade will be demonstrated. The influence of constrained layer damper design parameters on the blade noise reduction will be presented.
A post-flight ignition overpressure review for the Arex I-X test rocket.
Authors: Alvord David A.
Published: March 2010

Ares I-X post flight ignition overpressure review ignition overpressure (IOP) is an unsteady fluid flow and acoustic phenomena caused by the rapid expansion of gas from the rocket nozzle within a ducted launching space resulting in an initially higher overpressure wave. This wave is potentially dangerous to the structural integrity of the vehicle. An in-depth look at the IOP environments resulting from the Ares I-X solid rocket booster configuration showed good correlation between the pre-flight predictions and post-flight analysis results. Correlation between the chamber pressure and IOP transients showed successful acoustic mitigation, containing the strongest IOP waves below the mobile launch pad deck. The flight data allowed subsequent verification and validation of Ares I-X unsteady fluid ducted launcher predictions, computational fluid dynamic models, and strong correlation to historical shuttle data.
Near-field energy-based measurements of small solid rocket motors.
Authors: Gee Kent L. , Giraud Jarom H. , Blotter Jonathan D.
Published: March 2010

Results of detailed near-field energy-based measurements of small solid rocket motors are described. The 5-in. center perforated motors are tested to ensure thrust equivalence of Shuttle reusable solid rocket motor propellant samples. An array of four three-dimensional acoustic probes, located as close as two nozzle diameters to the plume shear layer, was located at nine positions for a total of 36 measurement points. The data collected were used to create maps of near-field energy-based quantities in the vicinity of the plume. In particular, the time-averaged vector intensity reveals the direction of the net acoustic energy flow away from the rocket plume, permitting direct characterization of the source region from these motors as a function of frequency. Further, these measurements establish the utility of energy-based acoustic quantities in aeroacoustic source measurement and modeling. [Work supported by an STTR from NASA Stennis Space Center. The cooperation of ATK Space Systems Test Services is gratefully acknowledged.]
Acoustic measurements for small solid rocket motors.
Authors: Vargas Magda B. , Kenny R. Jeremy
Published: March 2010

Rocket acoustic noise can induce loads and vibration on the vehicle as well as the surrounding structures. Models have been developed to predict these acoustic loads based on scaling existing solid rocket motor data. The NASA Marshall Space Flight Center acoustics team has measured several small solid rocket motors (thrust below 150 000 lbf) to anchor prediction models. These data will provide NASA the capability to predict the acoustic environments and consequent vibro-acoustic response of larger rockets (thrust above 1 000 000 lbf) such as those planned for the NASA Constellation program. This paper presents the methods used to measure acoustic data during the static firing of small solid rocket motors and the trends found in the data.
Cultural soundscape of the Grant-Kohrs Ranch national historic site.
Authors: Maher Robert C.
Published: March 2010

It is often noted that although many parks and historic sites look as they did a century ago, very few sound as they once did. Management principles of U.S. National Parks and Historic Sites include the need to “preserve soundscape resources and values of the parks to the greatest extent possible to protect opportunities for appropriate transmission of cultural and historic sounds that are fundamental components of the purposes and values for which the parks were established.” Therefore, a critical part of soundscape management is to determine the existing ambient soundscape to detect trends and changes. An ongoing project at Grant-Kohrs Ranch National Historic Site, located just north of Deer Lodge, Montana, involves a year-long continuous audio recording and soundscape characterization. The recording status and example soundscape excerpts are presented and discussed.
Biology of noise-induced hearing loss.
Authors: Liberman M. Charles
Published: March 2010

This talk will review recent research on the cellular and molecular changes underlying noise-induced hearing loss (NIHL) and potential therapeutic approaches to its prevention and/or mitigation. Topics will include (1) the functionally important structural changes underlying reversible versus irreversible NIHL, (2) the factors affecting vulnerability to NIHL, (3) the inadequacy of threshold testing as a measure of noise-induced cochlear damage, and (4) the possible utility of antioxidant and other chemical therapies.
Spectrotemporal integration in listeners with normal hearing and those with noise induced hearing loss: An application of the Meddis Matlab Auditory Periphery (MAP) model.
Authors: Feth Lawrence L. , Hoglund Evelyn M. , Oh Yonghee , Meddis Ray
Published: March 2010

Our recent study of spectrotemporal integration by human listeners with normal hearing has shown that the detection thresholds for signals made up of multiple bursts of brief tones improve as the number of bursts is increased. Elementary signals consisted of 10-ms tone bursts centered on 1 of 12 frequencies spaced 1 ERB apart. Complexes were constructed by adding individual tone bursts along the temporal or spectral dimension, or both. Quiet thresholds were measured using a one interval adaptive procedure. There was no significant difference in performance for a variety of time by frequency patterns used to construct the signals. Even random selection of tone frequencies for each signal presentation did not degrade integration performance. The current study measured spectral integration, temporal integration, and spectrotemporal integration in listeners with noise induced hearing loss as well as in normal-hearing listeners. The Meddis MAP model was adjusted to fit integration performance for the normal-hearing listeners and then used to predict the performance by NIHL listeners by modifying the outer hair cell parameters. [Research supported by a grant from the Office of Naval Research # N000140911017.]
National occupational research agenda for hearing loss in the manufacturing sector.
Authors: Murphy William J.
Published: March 2010

The National Institute for Occupational Safety and Health (NIOSH) has developed the National Occupational Research Agenda (NORA) as a means of organizing and prioritizing its research efforts in occupational safety and health. Research has been categorized across 8 industrial sectors and 22 cross-sectors. Among these, the manufacturing sector is the largest sector in which hearing loss occurs due to occupational exposures. The NIOSH Manufacturing Sector Council has developed strategic research goals to be completed by government, academic, and industry stakeholders. Foremost among these goals were the identification and inventory of sources of noise exposure resulting in hearing loss, and the determination of behavioral and exposure factors that contribute to the risk of hearing loss. This paper will outline the efforts of the Manufacturing Sector Council to identify research needs, outline research partnership opportunities, and seek effective means of implementing the research agenda to reduce the incidence of hearing loss among American workers.
Wave separation and signal isolation via line-scan supersonic acoustic holography.
Authors: Marston Timothy M. , Marston Philip L. , Williams Kevin L.
Published: March 2010

Pressure signals scattered from a target and received by a line array can be buried in noise having similar frequency content, such as reflections from nearby interfaces or objects adjacent to the target. In such circumstances, it may be difficult to isolate the desired signal through the use of standard linear time-invariant filtering techniques, because the frequency content of the signal and noise are identical. Supersonic line-scan holography, however, can be used in many such circumstances to achieve signal isolation by backpropagating the acoustic signal to a focal region, spatially and temporally filtering the signal around the focal region, and forward-propagating the isolated signal to the original array location. This technique was used to measure the bistatic angular scattering pattern of a small target driven at resonance. This was done in a water tank using a hydrophone scanned along a line. A demonstration of how this method was used to isolate the signal from larger, overlapping reflections will be given. The method was also applied to backscattering measured with a scanned transducer and fixed proud cylinder resting on sediment. [Work supported by ONR.]
Boundary enhanced helical ray coupling to high-frequency modes of solid aluminum cylinders.
Authors: La Follett Jon , Marston Philip L.
Published: March 2010

Surface guided leaky Rayleigh waves have been shown to provide a significant contribution to the backscattering by a solid metallic cylinder [K. Gipson and P. L. Marston, J. Acoust. Soc. Am. 106, 1673 (1999)]. Free field observations of the backscattering by solid aluminum cylinders confirm that both meridional and helical rays contribute to the backscattering for different angles of cylinder tilt [K. Baik, Ph.D. thesis, WSU (2008)]. Those studies show that a previously developed criteria, based on the length of the cylinder, limits the range of tilt angles for which helical rays can contribute [F. J. Blonigen and P. L. Marston, J. Acoust. Soc. Am. 112, 528 (2002)]. Experiments with solid aluminum cylinders placed near a flat reflecting boundary suggest that the presence of a boundary can increase the number of helical ray paths that contribute to the backscattering; this increase can lead to increased backscattering amplitudes and an increased range of angles for which coupling to helical rays can occur. To investigate this effect, solid aluminum cylinders were suspended below the free surface of a water tank. Targets were illuminated from below at grazing incidence, and the backscattering was measured as a function of target rotation. [Work supported by ONR.]
The true absorption—Measurements and coefficients.
Authors: Nocke Christian
Published: March 2010

Many measurement procedures for sound absorption rely on approximations or necessitate special restrictions. The measurements in the tube usually only cover small samples and rely on a plane wave at normal incidence of sound. Reverberation chamber measurements assume diffuse sound fields and other constraints. Furthermore sound absorbers might show local or non-local reaction, e.g., angle dependence of the acoustic surface impedance or not. The performance of sound absorbers, either in a room or outdoors, often involves neither plane sound waves nor diffuse sound fields. This is one motivation for the development of measurement procedures applicable where the sound absorber is actually used, namely, in-situ methods. The paper will present a short historical review on the development of measurement techniques of sound absorption or the acoustic surface impedance. Measurement examples will be shown for some of the methods presented and compared to each other.
Characterizing scattering coefficients numerically via the fast multipole accelerated boundary element method.
Authors: Gumerov Nail A. , Duraiswami Ramani
Published: March 2010

Various panels are used in acoustical installations to provide desired characteristics to spaces to be used for listening. These panels have complex shapes with geometrical features that have sizes corresponding to wavelengths of sounds of interest. The complex interaction of acoustical waves with these shapes is what gives these surfaces their desirable properties. Experimental characterization of the acoustical properties of these surfaces under random and specular incidence is relatively time consuming. An alternate procedure is to numerically simulate the scattering behavior, and then computing the coefficients of interest from the simulation. A significant obstacle to such computations is the time taken for simulation. Fast multipole acceleration of boundary element methods [Gumerov & Duraiswami, J. Acoust. Soc. Am. 125 (2009)] is a promising approach to speeding up computations. We report on the application of this method to the computation of various scattering coefficients.
Evolution and uses of the diffusion coefficient: 1994–2010.
Authors: D’Antonio Peter
Published: March 2010

A measurement method to determine the diffusion coefficient was first proposed at the Sabine Centennial Symposium in 1994. The method involved a boundary measurement technique which was carried out in a reflection free zone to determine the scattered impulse responses at 5 deg resolution from which the uniformity of third octave polar responses could be determined. In 2001, an information document (AES-4id-2001) was published describing this technique and the determination of the diffusion coefficient from the autocorrelation of the third-octave polar responses. This technique is being enshrined as ISO 17497-2, which will complement the scattering coefficient standard ISO 17497-1. This presentation will review the evolution of the diffusion coefficient, describe the current measurement and characterization technique, and detail its limitations and accuracy. Two examples of its use will be given. The first example will illustrate how the directional and random incidence diffusion coefficients can be used to evaluate the bandwidth and scattering uniformity of several potential one-dimensional and two-dimensional diffusing surfaces. The second example will demonstrate how the coefficient can be used as a metric to create new surfaces, using a shape optimization computer program, which combines boundary element and multi-dimensional minimization techniques.
Design of sound diffusion in concert halls using scale models.
Authors: Jeon Jin Yong , Kim Yong Hee
Published: March 2010

Effects of surface diffusion from lateral walls on concert hall acoustics were investigated to determine diffuser profiles. The design factors of diffusers in concert halls are geometrical shape, structural height, and surface coverage. Diffusion and scattering coefficients of the diffusers were measured in a 1:10 scale model reverberation chamber. Then, it was applied to scale model concert halls by design factors of diffusers. Acoustical parameters such as RT, EDT, C80, and sound pressure level (SPL) were calculated from the impulse responses. In addition, the numbers and amplitudes of the reflection peaks within −20 dB after the direct sound were calculated to evaluate the diffuseness in the halls. As a result, diffusers commonly yielded decrease in RT and SPL but contributed to increase in uniformity of RT and SPL. It was also found that the diffusive lateral surfaces close to the stage area are more effective in increasing both Np and ES. Appropriate design directions of diffuser are discussed from the measured results.
Characterizing rooms regarding reverberation time prediction and the sensitivity to absorption and scattering coefficient accuracy.
Authors: Dalenback B.-I. , Brown Sarah
Published: March 2010

Prediction of reverberation time (T30) using ray-tracing and similar algorithms naturally requires realistic input data, but the degree of data accuracy required varies with the room properties. In some types of rooms, accurate coefficients are crucial while in other types it is less crucial and the prediction results are less sensitive. This paper will attempt to classify rooms, according to their sensitivity to the input data due to their geometrical mixing (or diffusing) properties and the absorption, distribution. At the one end are found non-mixing geometries with uneven absorption, making a good estimate of the scattering coefficients crucial, at the other end are found mixing geometries with a mildly varying absorption distribution where prediction is safer and where estimated, or readily available, absorption coefficients can be used and where the choice of scattering coefficients has little impact. Due to the natural frequency dependence of both absorption and scattering coefficients the classification may also differ between octave-band predictions in the same room. Predictions are also difficult in rooms where the decay is not exponential. However, measures, e.g., STI and C80, may still be well predicted since they do not rely on fitting a straight line to a non-straight logarithmic decay.
Improving the accuracy of sound absorption measurements.
Authors: Moritz Charles , Shaw Jennifer , Carrera Armando
Published: March 2010

Sound absorption test methods, such as ASTM C423, provide criteria for test chamber qualification. Measurements required during the ASTM C423 qualification process examine the variation in decay rates with microphone and test specimen locations. In addition, it is recommended to measure the change in sound absorption coefficients of a reference specimen with various amounts of diffusion in the room. However, there is little published information regarding systematic methods for determining diffuser, microphone, or specimen locations; therefore, qualification or improvement to the reverberation room depends on the acoustician’s best judgment. As part of a continual improvement process to reduce testing variation, a mapping technique was utilized to visualize the three dimensional sound field in the room and determine changes necessary to improve the diffusion and repeatability of sound absorption measurements.
On the accuracy of the subtraction method for in-situ reflection and diffusion coefficient measurements.
Authors: Robinson Philip , Xiang Ning
Published: March 2010

The subtraction method is a technique critical to measuring in-situ reflection/absorption coefficients as well as diffusion coefficients. In order to isolate a reflection, a reference measurement including only direct sound is subtracted from one with direct sound and the reflection of interest. However, taking two measurements with exactly the same direct sound component is complicated by environmental conditions, such as changes in temperature, air movement, and exact microphone positioning. These variations can cause small time differences between the reference and the measurement which prevent complete subtraction of the direct sound; the residual direct sound then pollutes analysis of the isolated reflection. This work evaluates several methods to compensate for the differences to achieve minimal interference from the residual direct sound. A metric for gauging the success of the subtraction is proposed and the influence of the subtraction effectiveness on variations in the measured diffusion coefficient will also be discussed.
Metric for biological assessment of injury by percussive and decompressive exposure to impulsive sound.
Authors: Carlson Thomas J.
Published: March 2010

Field and laboratory assessment of barotrauma to fish caused by percussion and/or decompression is complicated by the occurrence of injuries that do not result in immediate mortality. Accurate estimation of the consequence of exposure to impulsive sound must consider injuries that result in mortality delayed beyond typical post-exposure holding periods of exposed animals or that debilitate and lead to indirect mortality. Research of the response of fish to impulsive decompression over the past several years has resulted in development of a metric, mortal injury, that appears to more completely describe the biological cost to juvenile fish of exposure to rapid decompression. This measurement method has been extended to assessment of the response of juvenile fish to exposure to impulsive sound caused by blasting. The implications for assessment of take of listed species by blasting is evaluated by comparing mortality assessed over a 48-h holding period following exposure with that by necropsy for determination of mortal injury immediately following exposure.
A model for predicting effects of sound on auditory sensory cells in fishes.
Authors: Hastings Mardi C.
Published: March 2010

Relationships among peripheral auditory mechanics, characteristics of sound exposure, and effects on auditory tissues in fishes are not understood. Several studies in the literature have reported varying degrees of damage to auditory hair cells in different species exposed to different types of sounds; however, there appears to be no correlation between sound exposure level and observed damage. In effort to understand mechanisms underlying hearing loss and hair cell damage and to predict their occurrence, a mathematical model of the peripheral auditory system in fishes was developed to study the dynamic response of the ear to incident sound in five different species. This model determines relative motion between the sensory epithelium and otolith in the inner ear, which causes bending of the apical ciliary bundles of auditory hair cells. Excessive relative motion predicted by the model was correlated with hair cell damage and found to be in good agreement with results of studies reported in the literature. Swim bladder geometry, otolith size, anatomical connections between swim bladder and inner ear, and spectral characteristics and amplitude of the received sound were found to affect the degree of hair cell damage. [Work supported by the International Association of Oil and Gas Producers.]
Marine bioacoustics in a changing Arctic.
Authors: Gisiner Robert C.
Published: March 2010

The retreat of summer ice in the Arctic during the past 5 years has been accompanied by a surge of alarm about iconic ice-associated marine mammal species: polar bears, walrus, ringed seals, and others. Changes for subarctic species of mammals, fishes, and planktonic organisms have not received as much attention, but will also need to be monitored. The paucity of data about Arctic marine mammals is now more than ever a serious impediment to good decision making. One of the greatest sources of hope is the tremendous advance in marine bioacoustic sensing technology that has occurred within the past decade. Passive and active acoustic technologies offer new means of obtaining biological data in a summer Arctic Ocean where ice is less available as a platform for animals and scientists, and in a winter Arctic Ocean that will continue to be one of the most difficult research environments in the world.
Effects of seismic exploration activities on bowhead whale call distribution in the Alaskan Beaufort Sea.
Authors: Blackwell Susanna B. , Nations Christopher S. , McDonald Trent L. , Thode Aaron , Kim Katherine H. , Greene Charles R. , Macrander A. Michael
Published: March 2010

Airgun use during seismic exploration activities is known to cause a decrease in call detection rates (used here as a proxy for calling rates) in migrating bowhead whales. However, the received airgun sound levels at the whales, at which behavioral changes occur, are not known. To address this question 40 directional autonomous seafloor acoustic recorders (DASARs) were deployed in autumn 2008 at five sites along the migration corridor of bowhead whales during ongoing marine seismic exploration activities. Over 440 000 whale calls were detected and localized by triangulation. Concurrently, over 100 000 airgun pulses were detected and analyzed. The study area was divided into a hexagonal grid (hexagon width 1.75 km). The received level (SPL and cumulative SEL) of airgun sounds was modeled for each hexagon in the study area and each 15-min period over the entire season, using information on the timing and location of airgun activities, the size of the airgun array being used, the depth of the DASARs recording the airgun sounds, and other covariates. Logistic regression was then used to model occurrence of whale calls as a function of received level, distance offshore, and other covariates. [Work supported by Shell Exploration and Production Company.]
From psychophysics to management of noise-disturbance in a large, Arctic carnivore, the polar bear.
Authors: Bowles Ann E. , Owen Megan A.
Published: March 2010

About 50% of maternal dens excavated by pregnant female polar bears on Alaska’s North Slope occur on land or land-fast ice. Management agencies and the public have raised concerns that noise from human activities could adversely affect denning female polar bears, causing den abandonment, interference with communication, altered habitat use, or behavioral and physiological stress. Although US Fish and Wildlife Service uses approach limits to prevent disturbance of denning females that are assumed to be conservative, no science-based standards have been developed and uncontrolled human activities are still possible. The potential for effects will be reviewed in light of published evidence and measurements of polar bear auditory thresholds [Bowles et al. (2008). J. Acoust. Soc. Am. 123, 3509] to show how an understanding of species-specific psychophysical characteristics is needed to assess the impact of noise disturbance from industrial activities. Scientific challenges to quantifying effects include identifying efficient noise metrics and practical methods for measuring adverse responses. The negative ramifications of disturbance may be intensified due to anticipated reductions in polar bear physical condition as their sea ice habitat declines.
Air-borne noise in the Arctic and implications for polar bears.
Authors: MacGillivray Alexander O , Erbe Christine
Published: March 2010

An increasing number of Arctic animal populations are listed as threatened. The list includes ungulates, terrestrial carnivores, marine mammals, and birds. Potential threats are habitat degradation and loss, pollution, prey depletion, harvesting pressure (as a result of human population growth), climate change, and noise. Growing exploration and industrialization of the Arctic come with an increase in underwater and air-borne noise. Sources of noise relate to oil, gas and mineral exploration and production, hydroelectric schemes, construction (of ports, buildings, roads), tourism, and traffic (marine, land-based and air). Noise and vibration measurements of land-based industrial activities will be presented, including excavation equipment, various types of ground vehicles, and blasting. Sound propagation characteristics will be explained. Results of a study measuring the transmission of industrial noise into polar bear dens will be shown and the potential effects of noise on Arctic animals will be discussed.
Acoustic propagation effects on airgun pulses and whale calls in the Beaufort Sea.
Authors: Kim Katherine H. , Thode Aaron , Greene Charles R.
Published: March 2010

In 2008, vocalizing bowhead whales (Balaena mysticetus) conducted their fall migration in the Beaufort Sea amidst short- and long-range seismic exploration activities. Whale calls and airgun pulses were recorded on five arrays of Directional Autonomous Seafloor Acoustic Recorders (DASARs) deployed along 280 km of Alaska’s North Slope. One particular sequence of pulses was recorded from the Louis S. St. Laurent, a Canadian geophysical vessel conducting surveys in deep offshore waters in collaboration with the United States Geological Survey (USGS), thus providing a fix on the location of some distant airgun activity. The distant airgun signals display an interesting selection of long-range propagation effects, which will be discussed and analyzed in the context of range-dependent propagation modeling in a combined deep-water upward-refracting and shallow-water bottom-interacting environment. [Work supported by the U.S. Geological Survey.]
Results and insights from operational acoustic monitoring networks in the Chukchi Sea, Summer-Fall 2006 and 2008.
Authors: Charif Russell A. , Warde Ann , Ponirakis Dimitri , Murray Anita , Muirhead Charles , Pitzrick Michael , Clark Christopher W. , Wisdom Sheyna , Rea Caryn
Published: March 2010

Recordings for marine mammals were collected in the Chukchi Sea in the 2006 and 2008 summer-fall seasons in proximity to seismic exploration activities. 2006 data were from MARUs off Cape Lisburne, Pt. Lay, Wainwright, and Pt. Barrow, AK. 2008 data were from MARUs in the Burger and Klondike areas. In 2006, belugas, but no bowheads, were rarely detected off Cape Lisburne in July–September. Bowheads, but no belugas, were detected off Wainwright, Lay, and Barrow in September–October, with bowheads very common off Barrow. Seismic airgun sounds were common on distant MARUs off Cape Lisburne, Lay, and Wainwright. There were very few seismic events detected off Barrow and those few were all close to 0-dB SNR. In 2008, bowheads were more common at Burger than Klondike and occurred mostly during the latter part of the September–October period; belugas were not detected at Burger and only on 6 days early in the period at Klondike; walrus were more common at Burger than at Klondike. In both areas bowhead densities were low-moderate. Seismic sparker sounds were detected on 7 and 28 days at Burger and Klondike, respectively, with higher received levels at Klondike.
A two-scale model to describe cavitation dynamics in viscoelastic media.
Authors: Labouret Stéphane , Collin Jamie R. T. , Coussios Constantin C.
Published: March 2010

In spite of several decades of research on cavitation inception and onset in biological media, the exact environment experienced by a cavitating bubble at the micro-scale and in the MHz frequency range remains poorly understood. Comparison of model-based predictions of bubble behavior with optical observations in transparent media suggests that the mechanical property values of the medium could be up to two magnitudes different than the corresponding static values. Several viscoelastic media, such as tissue or tissue-mimicking materials, have been recently shown to exhibit a sub-micron structure which can be assumed equivalent to a pure liquid up to a characteristic length scale and essentially viscoelastic thereafter. The present work proposes an extension to the model recently proposed by Yang and Church [J. Acoust. Soc. Am. (2005)] that takes this dual scale into account. Model predictions are validated against experimental results obtained by inducing single-bubble inertial collapses in an agar-based tissue mimicking material using short pulses produced by a 1.1-MHz HIFU transducer; the resulting acoustic emissions are acquired using a calibrated passive cavitation detector, thus enabling direct comparison with the inertial cavitation threshold and radiated sound amplitude predicted by the single-scale and novel dual-scale models.
Enhanced high inensity focused ultrasound-induced heating in a phantom.
Authors: Pemberton Labuda Cecille
Published: March 2010

High intensity focused ultrasound (HIFU) has the capability to induce hemostasis through rapid delivery of energy in the HIFU focal region. HIFU effectively induces hemostasis in small blood vessels; however, as vessel size increases, loss of heat to the flow increases until HIFU treatment is only minimally effective. A new method to enhance the HIFU-induced heating effect was investigated. Single polymer fibers embedded in a heat-sensitive phantom are shown to increase the size of HIFU-induced lesions as compared to controls. Polymer meshes were then embedded in the phantom and the size of the HIFU-induced lesions produced were compared with control lesions.
Effects of quadrupole and octupole modes on coupled nonlinear bubble interactions.
Authors: Kurihara Eru , Hay Todd A. , Kurtz Jason P. , Ilinskii Yurii A. , Hamilton Mark F.
Published: March 2010

Photographs of bubble cluster dynamics have shown that under sufficiently intense acoustic excitation, neighboring bubbles may undergo shape deformation and even form opposing liquid jets. Jetting is one of the chief mechanisms thought responsible for cavitation-induced erosion. Therefore, a better understanding of the phenomenon would be beneficial in improving the efficacy of and reducing collateral damage during medical procedures such as shock wave lithotripsy. Previous efforts to model aspherical collapse of a bubble near an interface have utilized purely numerical methods. In this presentation we derive dynamical equations for the coupled motion of two translating, aspherical gas bubbles. Deformation of the initially spherical bubble surfaces is taken into account by including quadrupole and octupole spherical harmonics in the boundary conditions on each bubble. For an axisymmetric geometry, this results in a set of eight coupled second-order ordinary differential equations that may be integrated numerically in time. The effect of surface tension and shear viscosity on quadrupole and octupole contributions is included in a consistent manner. Simulation results agree qualitatively with measurements and predict the formation of opposing liquid jets for bubbles which are sufficiently close to one another. [Work supported by NIH DK070618.]
A new acoustic lens design for electromagnetic shock wave lithotripters.
Authors: Smith Nathan , Simmons W. Neal , Sankin Georgy , Zhong Pei
Published: March 2010

The third-generation electromagnetic (EM) shock wave lithotripters often have narrow focal width and high-peak pressure compared to the original HM-3. In addition, the pressure waveform produced by a typical EM lithotripter has a secondary compressive wave that suppresses lithotripter pulse induced cavitation, which is an important mechanism for stone comminution. These features have been contributed to the reduced effectiveness of the modern EM lithotripters. To overcome these drawbacks, we have designed a new acoustic lens for the Siemens Modularis EM lithotripter that produces an idealized pressure waveform similar to the HM-3 with broad focal width and low-peak pressure. At acoustic pulse energy of 53 mJ, the new lens design enlarges the −6 dB focal width of the Modularis by 47% while significantly reducing the second compressive wave throughout its focal plane. After 2000 shocks, in vitro comminution produced by the original and new lens designs are 100% and 99% at the lithotripter focus, and (49.7±15.0)% and (75.3±8.74)% (p < 0.001) at 10 mm off axis, respectively. Corresponding values in vivo are (63.4±17.4)% and (83.3±8.5)% (p < 0.01), demonstrating the significant performance improvement provided by the new lens design. [Work supported by NIH Grant Nos. R01DK052985 and S10RR016802.]