bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of the acoustic environment on the launch pad for the Ares I rocket, including the effects of drift and water suppression.
Authors: Plotkin Kenneth J.
Published: March 2010

A model, PAD, has been developed for prediction of noise in the vicinity of launch vehicles, with specific application to the mobile launcher and tower for the Ares I launch vehicle. It follows the basic principles of a traditional NASA model [NASA Report No. SP-8072 (1971)] but uses an updated rocket sound power source model developed by Sutherland [AIAA Paper No. 93-4383 (1993)] together with updates for the distribution and directivity of sources along the rocket plume. The effect of the deflector on plume geometry and shielding by the launcher deck are included in the model. Overall and spectral (octave band or psd) levels are predicted at specific points or on a regular grid of lateral and vertical positions on and around the launcher. A basic version of PAD was used for nominal acoustic predictions for vertical lift with all exhaust flow going through the flame hole in the deck and no water suppression (AIAA Paper No. 2009-3163). The model has since been extended to account for lateral drift of the vehicle, with consequent impingement of the plume on the deck and for the effect of water suppression systems. [Work supported by the National Aeronautics and Space Administration.]
High-speed jet noise: A two source model.
Authors: Tam Christopher K. W.
Published: March 2010

Recent experiments on high-speed jets indicate that jet noise is made up of two components. One component dominates in a conical sector surrounding the jet axis in the downstream direction. Experimental evidence suggests that this noise component is generated by the large turbulence structures of the jet flow. The other component is dominant in the sideline and upstream directions. There is ample experimental evidence showing that this noise component is generated by the fine scale turbulence of the jet. Optical observations confirm that there is a separation of turbulence scales in jets. Jet turbulence consists of large structures with length scale of the order of the jet diameter and fine scale turbulence with a much smaller length scale. These two types of turbulent fluid motions, with large disparate length scales, co-exist in the first one and half core length of the jet. In this presentation, extensive far field noise and direct correlation data are provided to support the two-noise source model. The validity of the two-noise source model is also strongly supported by near acoustic field measurements.
An acoustical comparison of sub-scale and full-scale.
Authors: Haynes Jared M. , Kenny Robert J.
Published: March 2010

Recently, members of the Marshall Space Flight Center (MSFC) Fluid Dynamics Branch and Wyle Labs measured far-field acoustic data during a series of three reusable solid rocket motor (RSRM) horizontal static tests conducted in Promontory, UT. The test motors included the Technical Evaluation Motor 13 (TEM-13), Flight Verification Motor 2 (FVM-2), and the Flight Simulation Motor 15 (FSM-15). Similar far-field data were collected during horizontal static tests of sub-scale solid rocket motors at MSFC. Far-field acoustical measurements were taken at multiple angles within a circular array centered about the nozzle exit plane, each positioned at a radial distance of 80 nozzle-exit-diameters from the nozzle. This type of measurement configuration is useful for calculating rocket noise characteristics such as those outlined in the NASA SP-8072 “Acoustic Loads Generated by the Propulsion System.” Acoustical scaling comparisons are made between the test motors, with particular interest in the overall sound power, acoustic efficiency, non-dimensional relative sound power spectrum, and directivity. Since most empirical data in the NASA SP-8072 methodology are derived from small rockets, this investigation provides an opportunity to check the data collapse between a sub-scale and full-scale rocket motor.
Listen to the change of a soundscape.
Authors: Genuit Klaus , Fiebig Andre
Published: March 2010

The general understanding of soundscapes as musical compositions requires the analysis of the sonic environment as a whole as well as in its different facets comparable to the study of music. However, soundscape studies often differ in the way the investigated soundscapes are recorded. In addition, a lot of soundscape articles lack an exhaustive description of the measurement conditions and protocol. This impedes the comparison of soundscape studies and their results. Therefore, it seems there is a need for measurement guidelines to provide a common basis allowing for subsequent comparative studies. The authors have proposed in previous papers measurement guidelines which could help to establish a common ground with respect to soundscape measurements. To check the adequacy and applicability of the recommended procedures for the (physical) measurement of soundscapes, several recordings of historic places in Aachen are realized and analyzed. Here, binaural recordings are performed, which allows for an aurally-accurate reproduction of the environmental sound. In supplemental laboratory tests, the conflict between the experience of the sound in the real urban space and the listening in artificial test situations is examined. Furthermore, the paper presents the change of the soundscape and its composition over time.
Effect of noise-induced hearing loss on a multi-channel listening task.
Authors: Abouchacra Kim , Koehnke Janet , Besing Joan , Letowski Tomasz
Published: March 2010

Monitoring multi-channel radio communication is a common activity for many military and civilian professionals, such as those who work in tactical operation centers, command-control towers, and voice interception facilities. In such environments, communication is critical and errors in speech understanding could cost time, equipment, and even loss of life. When an individual has a hearing loss, these costs have the potential to increase substantially. The purpose of this study was to compare speech recognition scores (SRSs) of listeners with normal hearing and noise-induced hearing loss, when target messages were presented with two, three, or four interfering messages through various spatial and non-spatial auditory displays. For both groups, SRSs decreased for all display types as the number of competing messages increased. However, listeners with hearing impairment had significantly poorer SRSs than listeners with normal hearing, with decreases in scores ranging from 10%–25% in all conditions. While both groups benefited from spatial auditory displays, listeners with hearing impairment demonstrated significantly greater improvement in SRS than those with normal hearing. These findings support the use of spatial displays for multi-channel monitoring tasks and highlight potential costs associated with hearing loss especially in the absence of spatial displays.
Susceptibility to intense impulse noise: Evidence from the Albuquerque dataset.
Authors: Price G. Richard
Published: March 2010

For theoretical and applied reasons, there has long been an interest in the problem of susceptibility to hearing loss from intense sounds; yet no useful predictive indices have been found. Some evidence suggests that susceptibility cannot be considered as a constant for individual ears; however, thinking and experimental designs often assume that it is. A critical data set in this regard are the US Army’s Albuquerque studies [Johnson, D. L. (1994) USAARL Contract Report No. 94-2, U.S. Army Aeromedical Research Laboratory, Rucker, AL] in which human Ss were exposed repeatedly to explosive sources. An analysis of individual threshold shift data finds that of 28 instances in which ears showed a threshold shift 15 dB or higher, 25 Ss subsequently passed higher levels of exposure, sometimes much higher levels. This outcome was clearly contrary to the expectation that they were susceptible ears. Issues such as HPD fit and random elements in exposures are demonstrably a part of the problem. Susceptibility, at present, should probably be considered a statistical concept, appropriate to groups of Ss.
Noise-induced hearing loss in the U.S. Military: A review.
Authors: Humes Larry
Published: March 2010

This presentation will review some of the key findings of an Institute of Medicine committee report [Humes et al. Noise and Military Service: Implications for Hearing Loss and Tinnitus (The National Academies, Washington, DC, 2005.] on noise-induced hearing loss in U.S. military personnel since World War II. With regard to hearing loss, the majority of the data available at the time of the report were average group hearing thresholds from cross-sectional studies. Patterns of hearing loss consistent with noise exposure could be seen in several cross-sectional studies of military personnel. These average data indicated that hearing thresholds were worse in those groups with more years of military service. However, these cross-sectional data were not a sufficient basis for attributing greater hearing loss solely to a longer exposure to military noise while in the military. With the information available, it was not possible to establish the precise proportion of a given military population that developed noise-induced hearing loss during military service, the amount of hearing loss incurred, or the relative risk of noise-induced hearing loss for a given individual, based on his or her branch of military service, occupational specialty, or service era.
Development of therapeutics to protect the inner ear: Support from animal models.
Authors: Le Prell Colleen , Ohlemiller Kevin , Dolan David , Miller Josef
Published: March 2010

Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue. Although we once thought virtually all NIHL was a consequence of mechanical damage to cells in the inner ear, we now know that intense metabolic activity drives the formation of free radicals (short-lived, unstable, highly reactive clusters of atoms) in the inner ear. Studies in animals have clearly shown that free radicals formed during and after noise importantly contribute to NIHL, and many laboratories have demonstrated that free radical scavengers (“antioxidants”) reduce NIHL in animal subjects. Our group, including investigators at multiple institutions, has specifically shown that the combination of beta-carotene, vitamins C and E, and magnesium is highly effective in preventing NIHL and sensory cell death in guinea pigs and mice. Use of free radical scavengers, or antioxidants, to prevent noise-induced deficits has thus become a clinical research goal. Given the multitude of intracellular events that occur during and after noise, it is not surprising that other agents are also potentially useful therapeutic agents. Translational investigations are essential to confirm potential utility of these agents in the human inner ear.
Laboratory experimental results for synthetic aperture sensing applied to mine detection.
Authors: Walker S. C. , Kuperman W. A. , Aumary Stephane , Marais Ghislain
Published: March 2010

Recent interest in mine detection has focused on the use of synthetic aperture sonar (SAS) array processing techniques to improve the along track sensor resolution of mobile side looking sonar platforms. We present the results of a series of laboratory experiments designed to study the effectiveness of various SAS array processing techniques for detection, localization, and classification of proud and buried objects. The experiments are carried out on a small spatial scale at ultrasonic frequencies. Notably, we find it possible to detect, localize, and classify buried objects (on the order of a wavelength in scale) from a great distance (hundreds of wavelengths).
Characterization and modeling of synthetic aperture sonar imagery.
Authors: Lyons Anthony P. , Abraham Douglas A. , Johnson Shawn F.
Published: March 2010

The characterization and modeling of synthetic aperture sonar (SAS) image statistics are of importance for developing target-on-background detection and classification algorithms and for developing specialized filters for speckle noise reduction. A simple model is presented to predict the impact of amplitude scaling caused by seafloor ripples on SAS image speckle statistics. The continuous variation in scattering strength produced by ripples (i.e., ripple-induced changes in seafloor slope) is treated as a deterministic amplitude scaling on image speckle produced by the SAS imaging process. Changes in image statistics caused by ripples are quantified in terms of an effective K-distribution shape parameter. Agreement between shape parameter estimated from the scaling model and from SAS data collected in experiments off of Panama City, FL and off of the Ligurian coast of near La Spezia, Italy illustrates the efficacy of the model. [Work supported by ONR Grant Nos. N00014-04-1-0013 and N00014-06-1-0245.]
Small scale test bed for studying multiaspect and multistatic sonar systems.
Authors: Malvoso Patrick C. , Stroud John S. , Lim Raymond , Lopes Joseph L. , Dzikowicz Benjamin R.
Published: March 2010

A nominally 1:50 scale acoustic test bed is operational at the Naval Surface Warfare Center-Panama City Division (NSWC-PCD) to image free-field, bottom, and buried targets using multiaspect, bistatic, backscatter, forward scatter, and synthetic aperture sonar (SAS) techniques. The test bed is designed to test and study novel geometries and techniques faster and cheaper than can be done in the field. Using precise translational positioning systems mitigates any issues associated with positioning of multiple sonar platforms in the field. The use of two transmit and receive transducer platforms is superior to a single platform, which is restricted to purely backscattered imaging, for producing SAS images. With two platforms, one can generate four images, two using backscattered return data and two using data sent from one platform to the other. Thus, the system is inherently both dual aspect and bistatic. The setup, including the scaled sediment, acoustic sources and receivers, and computer controlled translational stages, is described. Preliminary beamformed data are presented showing the relationships between each of the images described above. In addition, techniques to mitigate the interference of direct path returns in forward-scattering geometries are discussed. [Work sponsored by the Office of Naval Research.]
Forward scatter target strength extraction in a littoral environment.
Authors: Kraus Larry A. , Berdoz Alain R. , Amon Danial L. , Frank Philip A. , Liskey Steve W. , Bucaro Joseph A. , Simpson Harry J. , Houston Brian H. , Calvo David C.
Published: March 2010

A rail-based system was used to collect forward and near-forward scattered echoes from a spherical shell in 14-m waters near Shell Island, Panama City, FL. The source was positioned 25 m from the scattering target and the 48-m horizontal rail on the opposite side, also 25 m from the target. The major obstacle to obtaining high-quality forward scatter target strength versus frequency and angle is the extraction of the much stronger time and position overlapping incident source signal. In previous laboratory measurements, this is accomplished with high precision by direct measurement of the incident field before the scattering target is positioned, a method not possible in a target search scenario or in a less stable environment. Here an attempt is made to obtain the forward scattered target strength by post-processing the received signals obtained in the littoral environment which contain both the echo and the overlapping source signal. The methodology involves using a wavenumber domain filter to remove the incident wave followed by standard synthetic aperture procedures to extract the desired target scattered signal. The resulting forward scattered target strength will be compared to what we expect analytically and experimentally from this simple target. [Work supported by ONR].
Comparison of measurement and simulation of the scattered pressure distribution from partly absorbing surfaces.
Authors: Dadiotis Konstantinos , Angus Jamie A. S. , Cox Trevor J.
Published: March 2010

When diffusion or scattering from a surface if discussed usually it refers to the distribution of pressure reflected from a rigid surface while the amount of reflected energy is not discussed. In this paper the scattered pressure distribution from surfaces that consist of absorbing and reflecting elements has been measured following the ISO 17497-2. The requirements of the standard were not perfectly met as the signal to noise ratio was lower than required due to the absorbing nature of the surface and high-low-frequency noise in the measuring system. The measured results were then compared with simulations using boundary element modeling. The comparison showed good agreement. Finally the issue of the reflected energy was discussed.
Simulating diffuseness with geometry variations of room surfaces.
Authors: Utami Sentagi S. , Navvab Mojtaba
Published: March 2010

Several methods have been proposed to quantify the sound-field diffuseness utilizing measurements, room-acoustic modeling, and subjective assessment. Methods for measurements require sophisticated equipment with special consideration limited on quantifying uniformity of diffuseness in reverberant chambers. This study provides a systematic technique in simulating the sound-field diffuseness. The room simulated is typical rooms requiring need to control problems of echoes where the sound energy is often need to be conserved as well. Theoretical consideration on the sound source characteristics, source to receiver distances, geometrical size of the room surfaces, and material characteristics is taken into account and being altered in the simulation. Detail of the geometry variations in room surfaces is the major concern. Typical parameters in room acoustics are utilized to quantify the sound-field diffuseness. The results have shown that the geometry variations are correlated with the following energy properties: (1) reverberation times, (2) energies of the direct sound and reflections, (3) ratio of early-to-reverberant energies, and (4) the ratio of intensities of sound waves impinging on surfaces and reflecting back with its directional distributions.
Higher-order impedance boundary conditions for finite difference solutions to the wave equation.
Authors: Bockman Alexander , Botts Jonathan , Xiang Ning
Published: March 2010

Higher-order finite difference methods for the solution of the wave equation are well established. The interchangeability of temporal and spatial derivatives allows for exact representations of the differential equation in difference forms to the order of accuracy desired. Realistic impedance conditions, however, germane to problems of an architectural acoustics origin, are typically given as ratios of pressure and velocity in the frequency domain. This work develops fourth order-accurate time domain boundary conditions for the types of materials typically encountered in the architectural acoustics field. Accuracy and agreement of numerical simulations to scale model measurements are compared and discussed, as is computational cost relative to lower-order methods.
Preliminary analysis of effects of pile driving sounds on fish.
Authors: Popper Arthur N. , Casper Brandon M. , Song Jiakun , Sanderson-Kilchenstein David , Carlson Thomas , Halvorsen Michele B.
Published: March 2010

There is continuing concern about the potential effects on fishes of the sounds produced during pile driving activities. Data in the literature are unclear as to physiological and behavioral effects. The earlier studies also generally did not include either experimental controls or control of signal parameters. We have developed a unique laboratory device that permits accurate simulation of impulsive pile driving signals in controlled experiments. Juvenile Chinook salmon were exposed to different combinations of sound levels and number of strikes to achieve various cumulative sound exposure levels. Controls received identical treatment as experimental animals, but without sound. The fish were evaluated by necropsy for assessment of barotrauma. Necropsies were conducted on exposed and control fish with experimenter not knowing the stimulus parameters. Preliminary analysis of results show that the extent of barotrauma rises with increased cumulative sound exposure level (SEL). Future experiments will examine effects of lower SELs as well as long-term effects that may arise at various time periods post-exposure. Ultimately, other species will be examined in order to develop broader criteria for exposure to pile driving sounds. (Work supported by NCHRP, CALTRANS, and MMS.)
Anthropogenic noise: Is this an issue for elasmobranch fishes?
Authors: Casper Brandon M. , Popper Arthur N.
Published: March 2010

Underwater anthropogenic noise has developed into a major national and international issue since it is becoming more apparent that human activities can have an adverse effect on the survival of fish stocks. It is unclear, however, whether human-generated noise in the aquatic environment could have an effect on the health and behavior of elasmobranch fishes (sharks, skates, and rays), a group already being threatened worldwide due to overfishing. Many sources of anthropogenic noise produce sounds in the frequency range detectable by these fishes; however, elasmobranchs are not considered to have sensitive hearing and therefore we do not know if they could be affected by these sounds. A review will be presented of what is known and unknown in regard to elasmobranch hearing abilities as well as behavioral studies in which sharks were exposed to or attracted by auditory stimuli. With these in mind, the goal will be to address whether anthropogenic environmental noise could be having deleterious effects on elasmobranch fishes.
Noise-induced hearing loss: From animals to humans.
Authors: Le Prell Colleen
Published: March 2010

Exposure to noise can result in neural swelling, mechanical damage, and/or a toxic accumulation of free radicals. The type and extent of the pathology, the amount of hearing loss, and the permanence of the hearing loss all vary with the level and duration of the noise insult. In addition, noise exposures in which sound level rapidly changes over time are more harmful than relatively constant level exposures. These relationships have been carefully worked out in animal models, and key findings will be reviewed. Evaluating the effects of noise on the human inner ear is more challenging. Exposures in the work place and other real-world environments can be challenging to control, and in those studies evaluating long-term effects of noise, the subjects are exposed to variable non-study noise sources. Exposures in the laboratory that induce temporary changes in human hearing carry their own challenges. In this lecture, we will discuss various human models for studies on the effects of noise, and we will present new data on temporary hearing changes in human subjects that listen to music with digital audio players. Several metrics used to measure the effects of noise will be discussed.
Effects of mid-frequency sonar on fish.
Authors: Halvorsen Michele B. , Zeddies David A. , Ellison William , Song Jiakun , Chicoine David R. , Popper Arthur N.
Published: March 2010

There is significant concern that high-intensity sounds can impact fish physiology and behavior. Important sources of such sounds are commercial and military sonars. A recent publication reports that exposure to low-frequency active (LFA) sonar might result in hearing loss in some fish species, but did not damage any tissues [Popper et al. (2007). J. Acoust. Soc. Am. 122, 623–635]. We have extended our studies to include U.S. Navy mid-frequency sonar. Fish were exposed to a 3-s-long signal that consisted of a 2-s 2.8–3.8-kHz frequency sweep, immediately followed by a 1-s 3.3-kHz tone). The stimulus was repeated five times with a 25-s interval. Fish were subsequently tested for hearing sensitivity and examined both grossly and microscopically for tissue damage. Some temporary hearing loss was found in catfish, species known to hear sounds above 1000 Hz, whereas there was no effect in fish which do not hear above about 1 kHz. There was no gross damage to any tissue, and microscopic examination showed no effect on any tissues. [Work supported by Office of the U.S. Chief of Naval Operations.]
Noise dose for aquatic animals: Preliminary estimates for two seismic surveys.
Authors: Handegard Nils Olav
Published: March 2010

In humans, a daily noise dose is defined and used to regulate noise exposure in the working environment. This is an integrated measure of sound intensity over the working day, typically 8 h in duration. When investigating behavioral effects on aquatic animals exposed to anthropogenic noise, a comparable measure would be valuable, especially when transient but powerful underwater noise sources such as seismic air-guns and mid- and low-frequency sonars are being used or are being considered for use. Here, an integrated noise dose measure is defined. Preliminary estimates of this noise-dose measure are given for two different seismic surveys.
Assessment of the acoustic effects on marine animals by an offshore wind farm.
Authors: Miller James H. , Potty Gopu R. , Vigness Raposa Kathleen , Casagrande David , Miller Lisa A. , Nystuen Jeffrey A. , Scheifele Peter M.
Published: March 2010

As part of the planning for an offshore wind farm in Rhode Island coastal waters, an assessment of the potential acoustic effects on the ecosystem is being conducted. The developer has proposed to initially deploy eight 3.6-MW wind turbines within 3 nm of Block Island. Two passive aquatic listener (PAL) systems were deployed south of Block Island from October 6 to November 11, 2008. Using data from the PALs, ambient noise histograms were computed for this pre-construction phase. The largest sources of noise in the area at low frequencies were found to be from shipping, wind, rain, and biological sources. In addition, transmission loss measurements were also made in the region to calibrate a geoacoustic model. Measurements of airborne noise from a 1.5-MW land-based wind turbine already in operation in Rhode Island were made in 1/3-octave bands and near the proposed windfarm site. A preliminary assessment of the effects of the offshore wind farm on marine animals at these sites will be presented. A plan for monitoring the noise field and potential biological effects during construction and operation of the windfarm is presented. [Funding provided by the RI Office of Energy Resources.]
Factors influencing biodiversity and marine animal habitat use in the Bering Sea.
Authors: Miksis-Olds Jennifer L. , Nystuen Jeffrey A.
Published: March 2010

A combination of active and passive acoustic technology was integrated into NOAA oceanographic moorings at two locations on the eastern Bering Sea shelf. Physical, biological, and acoustical oceanographic instruments made synoptic measurements of marine mammal presence, zooplankton/fish concentrations, physical oceanographic processes, primary production, and sound levels from 2008–2009. Synergistic factors influencing biodiversity and marine animal habitat use were investigated. Observed patterns in the central Bering Sea indicate that ecosystem dynamics and the acoustic environment are strongly driven by sea ice. Marine mammal presence and diversity were tightly coupled to sea ice presence. Bowhead whales and ice seals dominated the acoustic soundscape during the winter and spring, whereas geophysical signals dominated during the fall and summer months. Zooplankton abundance was also tightly linked to ice coverage. Time series of acoustic backscattering strength during the winter months indicated that the zooplankton community rapidly responds to short period of open water at a level that equals or exceeds maximum volume backscatter values at other times of the year. Integrated data such as these will be vital in understanding the relationship between marine mammals, zooplankton, and the physical environment. [Work supported by ONR.]
Right whale distribution in the Bering Sea revisited: A fresh look.
Authors: Crance Jessica , Berchok Catherine , Clapham Phillip , Lammers Marc , Au Whitlow W. L. , Mellinger David K. , Nieukirk Sharon
Published: March 2010

The North Pacific right whale (Eubalaena japonica) is one of the most endangered baleen whales in the world, with current abundance estimates of fewer than 40 individuals. As such, it has been the focus of intensive population monitoring studies. Long-term passive acoustic monitoring is a useful tool for assessing distribution, habitat use, and population status of marine mammals. For Bering Sea right whales, past analyses of distribution were based on their stereotyped upsweep call. Results from sonobuoy recordings made during the 2008 and 2009 southeastern Bering Sea right whale cruises, however, found gunshot calls to be much more common. To assess whether inclusion of gunshot call detections will change our understanding of the spatial and temporal distribution of North Pacific right whales, we examined four years (2006–2009) of long-term recordings made by the National Marine Mammal Laboratory and the Pacific Marine Environmental Laboratory at six different locations on the Bering Sea shelf. A comparison of the results using upsweeps, gunshots, and a combination of both will be presented. [Work supported by an Inter-Agency Agreement from the Minerals Management Service.]
Nonlinear distortion associated with high-intensity focused ultrasound creates apparent displacements in acoustic radiation force imaging.
Authors: Draudt Andrew B. , Cleveland Robin O.
Published: March 2010

An acoustic radiation force imaging (ARFI) system has been developed which employs a 1.1-MHz high-intensity focused ultrasound (HIFU) source to create the pushing beam (0.5–7-MPa peak pressure) and a focused 7.5-MHz transducer (mounted concentrically in a hole of the HIFU transducer) to create the imaging pulse. The motion of tissue is determined by recording multiple A-lines from the imaging transducer and using speckle tracking to estimate displacement. The HIFU was amplitude modulated to result in a time-varying radiation force and imaging pulses transmitted simultaneously in order to monitor tissue motion during the push phase. Measurements of the pressure waveforms in water indicated that nonlinear distortion of the HIFU could advance the arrival time of the imaging pulse if it was on a pressure peak and retard it if it was on a pressure trough, resulting in apparent displacements on the order of 5 μm. The apparent displacement varied with the phase at which the ARFI was transmitted and increased with the HIFU pressure amplitude. Experiments with ARFI in chicken breast indicated that the apparent displacement varied with depth which appeared to be related to differences in the diffraction patterns of the two sources. [Support NSF CenSSIS EEC-9986821.]
Rytov modeling for backscatter monitoring of high-intensity focused ultrasound therapy.
Authors: Speyer Gavriel , Kaczkowski Peter , Brayman Andrew , Crum Lawrence
Published: March 2010

Accurate monitoring of high-intensity focused ultrasound (HIFU) therapy is critical for ensuring proper treatment. Changes in time of flight for diagnostic ultrasound (DU) backscatter have been recognized as a means to identify temperature changes between two DU frames, captured before and after HIFU therapy. Estimates of heating from precisely controlled HIFU experiments strongly indicate that DU measurements are formed by an interaction between the heated material and a diffuse DU beam, as opposed to the commonly assumed ray model for the DU beam. The existence of a diffuse beam can be explained using the Rytov method, where temperature induced changes in material properties affect the phase and amplitude of the probing signal, with cumulative effects produced over characteristic volumes, and not simply depths. In particular, the temperature effect for on-axis backscatter is shown to be a generalization of the models proposed by Simon (1998) and Moreno (1996), with the phase determined by a complex weighted average of temperature in cross sections perpendicular to the DU beam axis. Results are illustrated using data obtained from gel phantoms, where the beam interaction is shown to provide therapy estimates consistent with the true therapy. [Work supported by NIH grant 5R01CA109557].
Pocket-sized ultrasonic surgical and rehabilitation solutions: From the lab bench to clinical trials.
Authors: Lewis George K. , Olbricht William L. , Henderson Peter
Published: March 2010

The use of ultrasound in medicine has quickly evolved in the last decade as a therapeutic modality and means to treat disease independently or in combination with other therapeutic regimes such as chemotherapy. The interaction of ultrasonic waves with soft mammalian tissues has the innate impact of enhancing tissue permeability to therapeutics, increasing local blood flow at low-acoustic powers, and causing tissue necrosis and cell death at higher-energy levels. We have developed multiple pocket-sized (4×2×1 in.) lithium battery powered therapeutic ultrasound units based off of our novel ultra-efficient electrical amplifier design that produces acoustic energies for low- and high-power applications (1–130 W). The portable ultrasound technology has been used in our laboratory to enhance ten-fold the delivery and efficacy of convection enhanced drug delivery to treat brain gliomas in vitro and in vivo. Our clinical collaborates at Weill Cornell Medical Hospital use our devices at high powers to non-invasively cauterize veins as a novel method of varicose vein treatment. Our clinical collaborators provide new avenues of ultrasound research and critical user feedback on the technology to aid refinements in its implementation in hand-held acoustic applications.
The homemade didgeridoo: An ancient acoustic resonator.
Authors: Greene Chad A.
Published: March 2010

The didgeridoo is an ancient Aboriginal instrument traditionally crafted from Eucalyptus trees which have been hollowed out by termites. The instrument is an excellent example of a simple one-dimensional acoustic resonator with a fundamental resonance corresponding to one-half wavelength. Today, the ubiquity and low cost of PVC pipes make didgeridoos inexpensive, easy to find, and trivial to construct from materials found at any hardware store. Students will have fun learning to make sounds with the instrument—perhaps they will even learn the technique of circular breathing—all while exploring fundamental principles of acoustics. As further investigation students can hum as they play, resulting in “beats, the speed of which can be adjusted by changing the pitch of the hum.
Homemade digital musical instruments.
Authors: Berdahl Edgar , Ju Wendy , Smith Julius O.
Published: March 2010

Homemade musical instruments are wonderful tools for getting students interested in learning about acoustics. Homemade digital musical instruments can similarly engage students, provoking them to learn more about the modern world surrounding them. In addition, the tools for developing homemade digital musical instruments are now becoming so easy to access that students can benefit from them too. The Arduino tool chain is introduced for interfacing sensing circuits with the computer over a USB port. Modern sensors are so simple that only a basic understanding of the voltage divider is required for building many useful sensing circuits. Synthesizing sound according to incoming data from the sensors is equally straightforward due to graphical environments commonly employed for sound synthesis programming. While many sound synthesis models are available, physical models of acoustic musical instruments are especially intriguing because students can relate to interacting with physical objects. Step-by-step instructions are provided for ordering parts and creating a simple but easily extensible homemade digital musical instrument that triggers sounds from a physical model of a vibrating string.
America’s next top physics rockers: A project based learning unit in which students build, perform, and explain homemade instruments.
Authors: Sabatier Charles H.
Published: March 2010

Project based learning requires that students engage with content in order to be successful in completing a project. This teaching method creates a need-to-know which motivates students to learn more so than the traditional physics unit. Knowledge and skills outside of the physics content such as preparing presentations, using tools and technology, and utilizing different writing styles are required to be successful in the project. Making the project authentic is necessary to truly motivate students to exceed expectations. In this particular project based learning unit, students have built their own musical instruments, performed a musical piece in a small group, and taught others about how their instruments work individually and as an ensemble. In completing this project, students learn about vibrations, resonance, amplitude, frequency, wavelength, and how the characteristics of their instruments affect these physics principles. In order to make this project truly authentic, the top students will be selected to perform and explain their instruments as part of this talk. All students participating in this project (pending funding) will attend the session and support their classmates in this presentation. If funding is not available, video clips of student performances and explanations will be substituted.
A case study in cooperation: A gravel pit and its community.
Authors: Duncan Edward , Kaliski Kenneth
Published: March 2010

It is often the case in the permitting and operation of gravel extraction and crushed stone quarries that aggregate companies and the local community are pitted against one another. This paper presents a case study of an existing gravel pit that came together with the community to work through concerns about the existing operations and a proposed expansion. The topics of discussion include the interesting dynamics involved in the consulting process, resulting mitigation to meet local standards and community concerns, conflicts of interests, and the local permitting process. The cooperative process used is presented in contrast to traditional systems using case studies of projects that have undergone permitting using more adversarial process models.
Limiting technology for modeling community noise from petrochemical facilities.
Authors: Brittain Frank
Published: March 2010

Modeling community noise is a vital part of designing any petrochemical, power, or industrial facility to meet community noise limits. Increasingly ray tracing, which is state-of-the-art software, is being used. Limitations of ray tracing can be categorized as those arising from the commercially available software (including ISO 9613 usually used for calculating outdoor propagation) and those related to input to the software. The former was covered by Brittain and Hale, Noise-Con 2008. The latter is covered in this paper. There are many technologies, which are needed to model community noise that are weak or for which data are not readily available. If the modeler understands where the technology is weak, then more effective models can be developed, and inaccuracies in the result can be better interpreted. Weak technologies or lack of data includes the following: modeling air coolers and cooling towers, modeling ducts and pipe racks, IL of pipeline and duct lagging, TL of building walls, noise radiated by building walls, source directivity, and—last but not least—getting accurate noise source data. Most of these become more critical at low frequencies. Each of these and their impact on design will be discussed.
Ray-tracing and spreadsheet modeling of power plant noise.
Authors: Hale Marlund E.
Published: March 2010

Community noise limits are often imposed on power plant designs. Many power plant sites are planned for rural locations where the residences are relatively close by or at some distance away. During the preliminary design of power plants, design options, along with any predicted environmental impacts and needed mitigation measures, are often discussed with appropriate regulatory agencies and local residents. A design phase noise model can be used to demonstrate the compliance status with local noise regulations. Several proprietary noise modeling methods have been developed by engineering and design-build companies. Spreadsheet noise models are often used to obtain a preliminary look at potential plant noise impacts. More sophisticated, commercially available, ray-tracing software is also available, but at a large initial cost in both time and money. Such modeling software allows one to model a large array of conditions and factors affecting noise propagation that are not possible using simple spreadsheet modeling. This paper compares the modeling results by both methods for two very different power plant sites, one surrounded by flat open terrain and the other located in a small valley surrounded by hilly forested terrain. Measured property line and community noise data are presented along with the modeling results.
Pipe noise prediction and sound insulation design by using modelling and field measurements.
Authors: Squadrone Giuseppe
Published: March 2010

Since engineering companies usually develop industrial complex by combining and connecting among them many static and rotating equipment with piping, the noise calculation and model of the latter are necessary when carrying out acoustic design to comply with occupational and environmental noise limits. According to the set of available input data, different design procedures can be followed both to model pipe noise and to design sound reduction systems, if needed. Examples of methods for piping noise modeling and insulation design, starting from inside or outside pipe noise levels given by equipment supplier or from in field measured noise or vibration levels, are here shown, analyzed, and discussed. Specifically, the paper describes case studies of steel piping system relevant to installation usually present in a generic industrial plant: a steam pressure reduction station, constituted by control valves and desuperheating devices; a large cooling water pump; and a feeding cooling water station where, accidentally, a regulation valve was excessively noisy. In-plant noise measurements after start up, for methodology reliability evaluation, are reported and discussed too.
The acoustic longevity of various pavements for noise reduction performance based on on-board sound intensity measurements.
Authors: Donavan Paul
Published: March 2010

When quieter pavements are used for purposes of reducing traffic noise levels, one issue of concern is how long will the noise reduction performance be maintained or what is its “acoustic longevity.” To address this issue, both the states of California and Arizona have established on-going research projects on a number of different pavement types including the broad groups of asphalt and portland cement concrete (AC and PCC, respectively). These pavements have been monitored routinely with on-board sound intensity measurements since the time of initial construction yielding data over periods of 4–7 years. The pavements consist of 11 PCC pavements of different texture and 13 AC sections of varying constructions. The results of these measurements are presented and discussed. In another approach of evaluating acoustic longevity, pavements of the same construction, but different years of build have also been evaluated to examine longer periods of time. The results of this approach are also presented along with a discussion of the issues involved with the two methods.
Quiet concrete pavement surfaces.
Authors: Rasmussen Robert , Whirledge Robert , Wiegand Paul
Published: March 2010

For the last 5 years, a comprehensive evaluation has been conducted on hundreds of concrete pavement surfaces throughout the US, Canada, andEurope. These data have been synthesized in a manner that allows the highway industry to make important decisions about how best to design and construct concrete pavements to reduce tire-pavement noise levels without compromising other important aspects such as durability, safety, and cost. While a significant amount of variability is present in the data, clear trends have been identified. Some surfaces, such as diamond grinding, appear to be among the best alternatives available today for reducing tire-pavement noise. Meanwhile, recent trials of more unconventional surfaces have yielded mixed results. In the end, the techniques for concrete pavement surfacing today include a vast array of choices. The selection of the best surface for the particular job can now be made more confidently given this improved understanding of the potential impacts due to tire-pavement noise.
Noise generation in contraction joints in Portland cement concrete.
Authors: Dare Tyler , Bernhard Robert
Published: March 2010

Contraction joints between slabs of Portland cement concrete have a major impact on measured tire-pavement noise levels. It has been proposed that during the interval when the contact patch of the tire is over the joint, the system acts as a Helmholtz resonator, and that this mechanism is responsible for the majority of the increased noise due to contraction joints. In this paper, this mechanism is investigated through theoretical calculations and experimentation. Intensity probes were used to measure noise near joints of varying widths using Purdue University’s Tire-Pavement Test Apparatus (TPTA). The TPTA was used to discover relationships between vehicle speed, joint width, and measured sound pressure and sound intensity spectra near the joint and the tire.
Experimental validation of finite element–boundary element model dynamic strain model under diffuse acoustic field loading.
Authors: Tsoi Ben , Gardner Bryce , Cotoni Vincent
Published: March 2010

Structural finite element (FE) models naturally output displacement or acceleration response data. However, they can also be used to compute stress, internal forces, and strain response. When coupled with a boundary element model (BEM) of the fluid surrounding the structure, a fully coupled analysis can be performed. Modeling a diffuse acoustic field in the BEM fluid provides an excitation like that found when the structure is placed in a reverberation chamber. Fully coupling the structural FE model to the acoustic BEM model provides a means to predict not only the acceleration response of the panel to diffuse field loading but also the ability to predict the dynamic stress and strain response. This type of model has been available with current predictive tools, but experimental validation of the prediction of dynamic stress or strain is difficult to find. An aluminum panel was instrumented with accelerometers and strain gauges and hung in a reverberation room and subjected to a diffuse acoustic field. This paper presents the comparison of the experimental and predicted results.
Systematic approach to passenger vehicle air induction tuning.
Authors: Szatkowski Antoni , Li Sean , Sandhu Jaspal
Published: March 2010

Air induction sound level and quality is a key contributor to in-vehicle powertrain NVH performance. This paper describes the process of tuning the air induction systems (AISs) at Chrysler LLC. Simple sound quality metrics are developed to quantify the AIS sound quality. Data acquisition and processing is standardized. A new methodology is presented, how to tune the AIS to meet the desired sound quality, and to optimize the cost, weight, and packaging space. Practical examples are presented to demonstrate how the specific targets are being achieved.