bluuebunny/crossref_metadata_2025 huggingface dataset:
The history detectives: Establishing the parameters of the 1960 Perth-Bermuda antipodal acoustic propagation experiment
Authors: Dushaw Brian D.
Published: November 2013

In 1960 three 300-lb explosive shots were detonated off Perth, Australia at 3 am, 22 March (local) by HMAS Diamantina to determine if those sound signals could propagate the antipodal distance to the Bermuda SOFAR station. These data offer a rare measure of the ocean temperature a half century ago, averaged across large stretches of the Southern, South Atlantic, and North Atlantic Oceans. The accuracy of these data are determined by the accuracy of the essential parameters of the experiment, e.g., the time and position of the shots. The narrative of HMAS Diamantina the night of 21 March 1960 was reconstructed from the ship's log, the captain's Report of Monthly Proceedings, and other information. The experiment was conducted with care to obtain a precise measurement, subject to the resources available to the ship at the time. The largest uncertainty is in the position of the shots, determined by triangulation from shore landmarks in the evening, celestial navigation at dawn, and dead reckoning in between. In addition, the depth was measured at the time of the shots. The 1960 position was measured to an equivalent travel-time accuracy of about 3 s, biased toward closing the range to Bermuda.
Fluctuations of the sound field in the presence of internal Kelvin waves in a stratified lake
Authors: Katsnelson Boris , Lunkov Andrey , Ostrovsky Ilia
Published: November 2013

In stratified lakes internal waves has great ecological significance since they affect mixing, resuspension, material transport, chemical regime and ecosystem productivity. Reconstruction of spatio-temporal heterogeneity of the basin scale internal waves and their accurate parameterization are important tasks. The effect of internal Kelvin waves (IKWs) on spatiotemporal variability of the mid-frequency (1 kHz) sound field in a deep lake using geoacoustic modeling is studied. It is demonstrated that IKWs cause significant fluctuations of the sound field, such as horizontal shift of interference structure. This shift can be easily measured in situ and used for practical reconstruction of IKW parameters. Overall, it is suggested implementing the low-cost geoacoustic methodology for accurate parameterization of the basin scale internal waves and studying their dynamics.
Broadband normal mode energy metrics in the presence of internal waves
Authors: Dossot Georges , Crocker Steven , Miller James H. , Potty Gopu R. , Badiey Mohsen
Published: November 2013

During the Shallow Water 2006 experiment a J-15 acoustic source deployed from the Research Vessel Sharp transmitted broadband (100–500 Hz) chirp signals 15 km away from a vertical line array. The array was intentionally positioned near the shelf-break front and in an area where internal waves are known to occur. Normal mode decomposition helps provide clues regarding the physics behind signal fluctuations due to internal waves, but often analyses are accomplished at single frequencies. A broadband modal beamformer approach is offered that extracts separate modal arrivals. A method for a mode-dependent matched filter is suggested which helps extract the separate arrivals in a low-signal environment. These methods can be used to compute mode-independent energy statistics which help explain signal fluctuations as an internal wave traverses the source-receiver path. [Work sponsored by the Office of Naval Research.]
Synthetic aperture geoacoustic inversion in the presence of radial acceleration dynamics
Authors: Tan Bien Aik , Gerstoft Peter , Yardim Caglar , Hodgkiss William
Published: November 2013

Traditionally matched-field geoacoustic inversion experiments sampled the acoustic field on long arrays and require powerful transmissions in order to reduce parameter uncertainty. However, single-hydrophone based geoacoustic inversion methods are attractive compared to the ones using long arrays. A low signal to noise ratio (SNR), single-receiver, broadband, and frequency coherent matched-field inversion that exploits coherently repeated transmissions to improve estimation of the geoacoustic parameters have been previously proposed. The long observation time creates a synthetic aperture due to relative source-receiver motion. This paper extends broadband synthetic aperture geoacoustic inversion to cases where the velocity of the source/receiver changes. In addition, a pulse-by-pulse coherent processing using the Bayesian approach is proposed. The method is demonstrated with low SNR, 100–900 Hz LFM data from the Shallow Water 2006 experiment.
Intensity statistics for dual-band, 500 km, ocean acoustic transmissions in the Philippine Sea 2010 experiment
Authors: Ganse Andrew A. , Andrew Rex K. , Mercer James A. , Worcester Peter F. , Dzieciuch Matthew A.
Published: November 2013

The May 2010 component of the North Pacific Acoustic Laboratory's Philippine Sea experiment included low-frequency transmissions over a 500 km path from the APL-UW ship-suspended multi-port source to a distributed vertical line array (DVLA) with 149 working hydrophones spaced over most of the water column. The multi-port source has two acoustic resonances at approximately 200 and 300 Hz. To accommodate those resonances in this experiment, two M-sequence signals at those center frequencies were transmitted simultaneously. Data recorded over a 60 h data window in the experiment show deep fades in both frequency bands, i.e., frequency-dependent variations of 10–20 dB in acoustic arrival intensities on the DVLA. The measurements are processed with Wiener filtering based on source-monitoring receptions of the transmission on a hydrophone 20 m from the source, to compensate for effects of the power amplifier and the transducer. Statistics of the received acoustic intensities are reported for both frequency bands. Correlations in the intensity between these broadly separated frequency bands allow one to explore questions of the role in arrival-splitting (micro-multipathing) in the deep fades observed in this experiment. [Work supported by ONR.]
A numerical model for large-amplitude spherical bubble dynamics in tissue
Authors: Warnez Matthew T. , Johnsen Eric
Published: November 2013

In a variety of therapeutic and diagnostic ultrasound procedures (e.g., histotripsy, lithotripsy, and contrast-enhanced ultrasound), cavitation occurs in soft tissue, which behaves in a viscoelastic fashion. While stable bubble oscillations may occur in ultrasound, the most dramatic outcomes (tissue ablation, bleeding, etc.) are usually produced by inertial cavitation. Historically, Rayleigh-Plesset equations have been used to investigate the dynamics of spherical bubbles, including in biomedical applications. For large-amplitude bubble oscillations in tissue, it is clear that compressibility, heat transfer and nonlinear viscoelasticity play important roles. However, no existing model includes all of these effects. To address this need, we use a compressible Rayleigh-Plesset equation (Keller-Miksis) adjoined with heat conduction in conjunction with an upper-convected Zener viscoelastic model, which accounts for relaxation, elasticity, and viscosity. The partial differential equations describing the stress tensor components in the surrounding medium are solved using a spectral collocation method. The method proves to be robust even for strong bubble collapse. Numerical comparisons with previous models are made, comparisons to experiments are included, and the dependence of bubble dynamics on viscoelastic parameters is explored. This model is used to revisit the inertial cavitation threshold in biomedical settings.
Shell material parameter measurements of polymer ultrasound contrast agents
Authors: Anastasiadis Pavlos , Allen John S. , Chitnis Parag V. , Ketterling Jeffrey A.
Published: November 2013

Polymer shelled ultrasound contrast agents have been used in ultrasound imaging and tissue perfusion studies. The destruction of the agent produced by the rupture of the shell often through complicated buckling has been quantified with overpressure experiments and optical visualization. Approximate material parameters have been correspondingly estimated with this methodology but additional steps are needed to translate for a viable high throughput technique. Ultra-high frequency acoustic microscopy (1 GHz) provides a non-invasive method to image and measure the shell's elastic properties. Scanning acoustic microscopy at 1 GHz is used to determine the shell density and elastic modulus for polymer shelled agents of three different shell thicknesses. The effect bending thickness is estimated for comparison with overpressure experiments.
Subharmonic response and threshold of polymer ultrasound contrast agents
Authors: Hayashi RIntaro , Allen John S. , Mamou Jonathan , Chitnis Parag V. , Ketterling Jeffrey A.
Published: November 2013

Analytical expressions for subharmonic threshold previously developed for free gas bubbles often been generalized and used for ultrasound contrast agents. However, many of those formulations were developed under the assumptions of mono-frequency steady state, continuous acoustic forcing which are typically not applicable to diagnostic and therapeutic ultrasound. Nonstationary subharmonic responses are investigated by analytical and numerical methods. The subharmonic threshold is investigated as means to differentiate between the proposed constitutive formulations of polymer shells in terms the shear modulus parameter. The potential influence of other agents in close proximity on the subharmonic response and threshold is highlighted with respect to the phase interaction between coupled agents.
Effects of ambient pressure variation on the subharmonic response from contrast microbubbles: Effects of encapsulation
Authors: Mobaderasny Nima , Sarkar Kausik
Published: November 2013

We investigate the ambient pressure dependent subharmonic response from encapsulated contrast microbubbles for non-invasive estimation of local blood pressure. We have previously found that the subharmonic response from a free microbubble can either increase or decrease or vary nonmonotonically [Katiyar et al., J. Acoust. Soc. Am. 129, 2325–2335] depending on the ratio of the excitation frequency to the resonance frequency (f/f0). Here, we extend this work to encapsulated microbubbles assuming various interfacial rheological models for the encapsulation. With an exponential elasticity model, the general trend remains similar to that of the free bubble. However, one also obtains chaotic oscillations at very low excitation frequencies and smaller damping coefficients. The specific trends are also disrupted when excitation pressure is increased or bubble size is changed. In the talk we will discuss the effects of variations in radius and different parameters of the encapsulation. [Work partially supported by NSF.]
Probing the bioeffects of cavitation at the single-cell level
Authors: Yuan Fang , Sankin Georgy , Yang Chen , Zhong Pei
Published: November 2013

Cavitation induced bioeffects has not been resolved satisfactorily due to the randomness in the inception and bubble dynamics produced by ultrasound. We have developed a microfluidic system to observe consistently the interaction of laser-generated tandem bubbles (50 μm in diameter) with resultant jet formation, cell deformation, and localized membrane rupture with progressive diffusion of propodium iodide (PI) into individual HeLa cells placed nearby. We observe a clear stand-off distance (SD) dependence in the bioeffects produced by the tandem bubbles. At SD of 10 μm, all cells underwent necrosis with high, unsaturated level of PI uptake. At SD of 20~30 μm, 58 to 80% of the cells showed repairable membrane poration with low to medium but saturated level of PI uptake. Within this range, the sub-population of cells that survived without apoptosis increased from ~9% at SD of 20 μm to ~70% at SD of 30 μm. The maximum PI uptake, pore size, and estimated membrane strain, however, could vary by more than an order of magnitude at each SD. At SD of 40 μm, no detectable PI uptake was observed. This experimental system provides a unique tool to probe the bioeffects of cavitation at the single cell level.
Magnetic targeting of microbubbles at physiologically relevant flow rates
Authors: Owen Joshua W. , Rademeyer Paul , Stride Eleanor
Published: November 2013

The localization of microbubbles to a target site has been shown to be essential to their effectiveness in ultrasound mediated drug delivery and gene therapy. The incorporation of super paramagnetic nanoparticles into the microbubble coating enables them to be manipulated using an externally applied magnetic field. Magnetic microbubbles have been shown to be effective in therapeutic delivery both in vitro and in vivo in a mouse model. The aim of this experiment was to determine under what conditions in the human body magnetic microbubbles can be successfully imaged and targeted. Different flow rates and shear rates were generated in a tissue mimicking phantom and targeting was observed using a 9.4 MHz ultrasound imaging probe. For the highest shear rates, targeting was also observed optically. Results indicate that magnetic microbubbles can be successfully targeted at shear rates found in the human capillary system (>1000/s) and at flow rates found in the veins and smaller arteries (~200 ml/s). Successful retention was also demonstrated in a perfused porcine liver model simulating conditions in vivo. This study provides further evidence for the potential of magnetic microbubbles for targeted therapeutic delivery.
Device for detection of cavitation in by spectral analysis in megasonic cleaning
Authors: Zanelli Claudio I. , Howard Samuel M. , Giridhar Dushyanth , Yam Petrie
Published: November 2013

The authors present a device and a method to detect cavitation in megasonic cleaning environments. The device is small enough to fit between wafers in the semiconductor industry, allowing the monitoring of the cleaning process.
A meshless bubble filter for an extracorporeal circulation using acoustic radiation force
Authors: Mino Koji , Kataoka Manami , Yoshida Kenji , Koyama Daisuke , Nakamura Kentaro , Omori Masayoshi , Kawarabata Shigeki , Sato Masafumi , Watanabe Yoshiaki
Published: November 2013

Arterial filters are employed in extracorporeal circulations to remove microbubbles and thrombus from the blood flow and prevent the emboli. Filters with mesh structure have a risk to generate the thrombi when the blood flows through it. In this report, a meshless filter using ultrasound is discussed. The filter consists of an aluminum cylinder (length: 130 mm; inner diameter: 30 mm) and two annular ultrasound PZT transducers. The filter has one inlet at the center of the side and two outlets at both ends. By exciting the transducer, the acoustic traveling wave can be generated in the liquid inside the filter. Air bubbles flowing from the inlet can be led toward the outlet by acoustic radiation force. The characteristics of the filter were investigated through a circulation system using distilled water at the driving frequencies of 200 kHz and 1 MHz. Flow and injected air were set as 5.0 l/min and 10 ml/min, respectively. The microbubbles were filtered by using ultrasound and the amount of filtered bubbles was increased with theinput voltage to the transducer: 50.6 and 53.7% of microbubbles were filtered at 200 kHz and 1 MHz, respectively, when the input voltage was 100 Vpp.
Digital fabrication of vocal tract models from magnetic resonance imaging during expert pitch bending on the harmonica
Authors: Granzow John , Egbert Peter , Barrett David , Rossing Thomas , Shin Lewis
Published: November 2013

Expressive pitch bending on the harmonica requires the acoustic coupling of contiguous free reeds, an effect known to arise from highly constrained vocal postures. These techniques have been difficult to demonstrate and instructors often rely on associated vowels to help novices achieve the required constriction of the vocal tract. Magnetic Resonance Imaging (MRI) was recently used to expose the precise vocal contours involved in such expert pitch bends (Egbert, etal., J. Acoust. Soc. Am. 133, 3590 (2013). To further this investigation, we process the MRI data using 3D slicing software, generating digital models of the vocal tract during sustained bends. In addition to providing volumetric data, the models are also fabricated with fusion deposition modeling and tested on real harmonicas. These tests reveal error tolerances in the conversion from MRI slices to 3d printed models when working with geometries that are highly constrained by a desired acoustic output. Furthermore, comparisons between human performance and simulated output provide clues to the contribution of factors not reproduced in the plastic models such as pharynx dilation.
A study of oboe reed construction
Authors: Gjebic Julia , Gipson Karen , Vavrikova Marlen
Published: November 2013

The construction of reeds is of much interest in the oboe community, because professional oboists spend as much time making reeds as they do practicing. Each oboist uses an individual methodology resulting from different training and personal physiology. To investigate how different reed construction affects the resulting sound, 22 professional oboists were recruited to make three reeds apiece for this study. First, a controlled batch of reed cane (internodes of the grass Arundo Donax) was selected based on microscopic inspection of cellular composition as well as macroscopic physical attributes. For most of the participants, the cane was then processed identically to the stage known as a blank, after which the participants finished their reeds according to their usual methods. (The few participants who made their own blanks still used the controlled cane and also a controlled staple, the metal cylinder that attaches the reed to the oboe.) The sound spectra of recordings of each participant playing on his/her respective reeds were analyzed, as was a spectrum of the crow (sound without the oboe attached) of each reed in an anechoic chamber. These spectra were correlated to measured physical characteristics of the reeds.
Analyzing the time variance of orchestral instrument directivities
Authors: Buck Adam T. , Wang Lily M.
Published: November 2013

Thirteen-channel anechoic recordings of 20-s musical excerpts for violin, flute, and bass trombone were analyzed to determine how significantly an instrument’s directivity changes as it is played. A clearer understanding of the time variance of instrument directivities may help in the advancement of room acoustical computer modeling, as the source properties are crucial to the simulation’s accuracy. Previous research has accurately documented the static spatial characteristics of instrument directivities. A multi-channel auralization technique incorporating time-varying source behavior has been developed, but the time variance of the directivities has yet to be explored. In this project, a time-windowing technique was utilized to calculate the directivity index throughout each channel recording for each instrument. The results were analyzed in terms of maximum directivity index and a sampling of complete directivity patterns, and finally used to explore quantification methods. The time variations displayed by each instrument’s directivity were unique in terms of magnitude, direction, and frequency. Calculating the average change in directivity index for each channel at each frequency band was found to be a suitable method for summarizing the results. [Work supported by a UNL Undergraduate Creative Activities and Research Experience Grant.]
Testing a variety of features for music mood recognition
Authors: Kostek Bozena , Plewa Magdalena
Published: November 2013

Music collections are organized in a very different way depending on a target, number of songs or a distribution method, etc. One of the high-level feature, which can be useful and intuitive for listeners, is “mood.” Even if it seems to be the easiest way to describe music for people who are non-experts, it is very difficult to find the exact correlation between physical features and perceived impressions. The paper presents experiments aimed at testing a variety of low-level features dedicated to music mood recognition. Musical excerpts to be tested comprise individual (solo) tracks and mixes of these tracks. First FFT- and wavelet-based analyses, performed on musical excerpts, are shown. A set of “energy-based” parameters is then proposed. These are mainly rms coefficients normalized over the total energy derived from wavelet- based decomposed subbands, variance and some statistical moments. They are then incorporated into the feature vector describing music mood. Further part of experiments consists in testing to what extent these features are correlated to the given music mood. Results of the experiments are shown as well as the correlation analysis between two main mood dimensions—Valence and Arousal assigned to music excerpts during the subjective tests.
Crack detection in long rod by impact wave modulation method
Authors: Sutin Alexander , Haskins Richard , Evans James
Published: November 2013

Engineering Research and Development Center (ERDC) in Vicksburg, MS, is interested in methods of microcracks detection in extended length and conducted test of applications of nonlinear wave modulation spectroscopy (NWMS). This is one of the simplest methods of nonlinear acoustic NDE. It is based on measurements of the modulation of a high frequency wave by a low frequency vibration. NWMS can detect the crack presence but cannot localize cracks. We present modification of NMWS method based on the modulation of by ultrasound by short pulse produced by impact. This method allows crack and damage localization using time delay of the impact produced pulse and modulated part of high frequency wave. The feasibility test was conducted for 60 ft long steel trunnion rod with an imitated crack. The continuous wave ultrasound with the frequency about 50 kHz was modulated by the longitudinal impulse produced by the hammer impact. Time delay between the impact and the received modulated ultrasonic wave allowed finding of the distance to the crack. Propagation speed of the modulated wave was lower than the speed of the hammer impulse as it is followed from the theory describing frequency dispersion of the waves in rods. [The project is funded by the Navigation Research Program at ERDC.]
Average radiation force at high intensity: Measured data
Authors: Solokhin Nick V.
Published: November 2013

Measurements were done in water at room conditions with HIFU transducer (at frequencies 3.1 and 4.3 MHz, max. pressure amplitude was 6—8 MPa). Average radiation force (ARF) was measured with flat reflecting target at normal incidence. The target was moved along the acoustic axis of the transducer: distance varied from 0.7 F to 1.4 F (F is focal distance). Measured ARF was growing with the distance (~25%) and it got max at distance 1.2 F. This effect meets with growing of nonlinear distortions at growing of intensity and length of passed way. It was measured dependence of ARF upon the angle of incidence and with same target. Measurements were done at incident angles 0, 30, and 60 degree. ARF changed from max value (at 0 angle) and reduced to 0.5 max value at 60 degree.
An investigation of the subjective quality of non-linear loudspeaker models employing Volterra series approximations
Authors: Richter Ian
Published: November 2013

This investigation is an extension of the work of Angelo Farina on the use of Volterra-series approximations to model acoustic systems. Farina's method uses a logarithmically swept sine chirp to extract the transfer function of a system, including its harmonic nonlinearities. I have used this approach to construct computer models of several loudspeakers. I then evaluated my models using a blind listening test to compare their outputs against recordings of the actual loudspeakers. The results of the blind test suggest that, while this algorithm is not sufficient to convincingly model the loudspeaker transfer function, it might be useful as part of a multi-stage algorithm.
New formulae for horizontal coherence from path integral theory
Authors: Colosi John
Published: November 2013

Previously published path integral results for the horizontal coherence length utilized an empirical relation for the phase structure function density that scaled as lag to the three-halves power. Here, a Taylor series expansion is carried out such that the phase structure function density scales instead as the second power of lag, consistent with other path integral coherence scales such as depth and time. The resulting integral equations are solved analytically. The new result shows the expected one over square-root range and one over frequency scalings, and it demonstrates more clearly how transverse coherence is sensitive to the space-time scales of ocean sound-speed perturbations.
Deep fades in intensity: Exploration of measurement-Monte Carlo parabolic equation mismatch in the Philippine Sea
Authors: White Andrew W. , Andrew Rex K. , Mercer James A. , Worcester Peter F. , Dzieciuch Matthew A. , Colosi John A. , Van Uffelen Lora J. , Howe Bruce M.
Published: November 2013

The oceanography of the Philippine Sea is partially characterized by energetic mesoscale and strong locally generated internal tides. Despite the simplification of range-independence and the exclusion of internal tides from Monte Carlo parabolic equation (MCPE) simulations, predictions of scintillation index, variance of log-intensity, and the distribution of intensity for acoustic paths with upper-turning-points (UTP) below the extreme upper ocean generally agree with measurements made during an experiment in 2009. These measures of the fluctuations did not appear to be strongly influenced by the number of UTPs in the path, though a compensating effect due to differences in UTP position cannot be ruled out. Enhanced variability in the form of deep fades is observed for paths turning in the extreme upper ocean; this enhanced variability is not predicted by the MCPE model employed. Seaglider-based observations of mixed-layer depth (from 2010 to 2011) and moored measurements of internal-tide-related sound-speed perturbations are presented. A plane-wave internal-tide model and results from acoustic mode propagation through range-independent profiles measured in situ are compared with the observed character of the intensity fades.
A new way of determining the total absorption of gypsumboard wall structures
Authors: Sauro Ronald
Published: November 2013

Gypsumboard wall construction is used throughout the United States and other parts of the world. Measuring the absorption of wall structures has been done in ways that always leave questions as to the efficacy of the measurement. Walls have been laid down on the floor and measured, and stood straight up and measured. Both methods leave questions as to the data because of differing results. There are questions about diaphragmatic movement that affects the absorption and its constrainment. We are proposing a different method that we think solves the problems inherent in each of the other methods, and we are presenting the results of measurements of indicated materials and comparisons with other methods
An innovative acoustic muffler to reduce acoustic leakage from recessed lights, intake vents, exhaust vents, etc., while improving the acoustic environment within a room
Authors: Schnitta Bonnie
Published: November 2013

In 2011, Bonnie Schnitta of SoundSense received a patent for an Acoustic Muffler. This Muffler addresses the issue of significant sound transmission, or acoustic leakage, through openings in structures, such as a ceiling or wall, where airflow or heat dissipation is required. Examples of applications will be presented, such as openings created by recessed lights, speakers, or intake and exhaust vents. These openings in the structure significantly reduce the STC and/or IIC of the structure. The SoundSense Acoustic Muffler reduces acoustic leakage through an opening in a ceiling or wall that would potentially cause significant degradation in acoustic efficacy of the structure without resulting in any substantial pressure drop, while simultaneously allowing for the required air flow or heat dissipation. The original application of the recessed light and additional similar applications as well as secondary purposes for this muffler will be detailed. One such secondary purpose is when the hole created by the recessed lights in the ceiling contributes to the room sounding better. The patented muffler not only allows this benefit to remain, but serves to inhibit the frequency(s) of concern from disturbing adjacent rooms. Cell tower equipment room noise reduction requiring airflow will also be detailed.
A comparison of predicted total absorption of different sized and shaped materials using traditional “absorption coefficient” vs a proposed absorption constant
Authors: Sauro Ronald
Published: November 2013

After using traditional absorption coefficients and calculating total absorptions for a room and then underestimating room RTs, it was decided that a new constant was needed that could be used to determine actual absorption of a surface. A constant was developed that meets this need and this paper shows the differences in the predicted absorptions using both methods vs using the new constant and the advantages of using the new constant.
Uncertainty of normal-incidence absorption coefficient measurements using the two-microphone cross-spectral method
Authors: Blevins Matthew G. , Thede Joshua , Wang Lily M.
Published: November 2013

Measured absorption coefficients have some uncertainty that can be expressed in terms of the uncertainty associated with each measured input quantity. The uncertainties of input quantities contribute to the combined uncertainty of the absorption coefficients in varying degrees dependent on the underlying relationship between each parameter. In this study, the propagation of uncertainty of the two-microphone cross-spectral method for measuring normal-incidence absorption coefficients is analyzed according to the ISO/IEC Guide 98-3:2008 “Guide to the expression of uncertainty in measurement.” The results of an experimental investigation are explored to determine the chief sources of systematic error and the relationship between uncertainty of input quantities and uncertainty of intermediate calculations.
Optimization of sound absorption performance of a new ecological material
Authors: Karabulut Seda , Çalışkan Mehmet
Published: November 2013

Material selection is foremost design parameter in providing acoustical comfort levels in both acoustically sensitive and noise generating spaces ranging from the small size meeting halls to large scale multipurpose auditoriums and even from foyers to shopping malls. Architects usually prefer seamless, unperforated materials in line with their interior design concepts. One of the objectives of this research is to contribute to the market portfolio of smooth faced, seamless acoustical materials with highest sound absorption performances. Another objective is to develop such a composition with ecological and sustainable ingredients, and binding techniques. Energy efficient and sustainable materials are frequently devised in construction industry for acoustically sensitive environments to get credits for international certification procedures such as LEED and BREEAM. Nevertheless, most of the acoustic materials in construction industry are perforated and/or supported with mineral wool based material backing, which have an adverse effect on indoor air quality. This article is on the improvement of an ecological unperforated sound absorptive material which is made of reed and pumice stone layers. The feasibility and effectiveness of a proposed configuration have already been studied. This paper seeks ways of optimizing number and thicknesses of different material layers in attaining maximum sound absorption performance.
Acoustic determination of impedance tube microphone locations
Authors: Fackler Cameron , Pitney Theodore S. , Xiang Ning
Published: November 2013

Impedance tube methods allow for convenient, rapid characterization of the normal-incidence acoustic properties of materials and constructions. Many such methods rely on the determination of precise phase relationships between microphones sensing the sound field inside the impedance tube; knowledge of the location of these microphones is crucial to the accuracy of the measurement. Due to the large physical size of typical microphone diaphragms, physical measurements of the microphone positions (such as with a ruler or caliper) are inadequate and have a large uncertainty. This paper presents a method to determine the impedance tube microphone acoustic center locations from a broadband acoustic reflection coefficient measurement of a rigid termination. Utilizing the Bayesian inference framework, the estimation procedure provides information about microphone locations and uncertainties in the position estimates.
Detection of specular and diffuse reflections in concert halls using continuous wavelet transforms
Authors: Jeon Jin Yong , Imran Muhammad
Published: November 2013

Specular and diffuse reflections have been detected in fine spatio-temporal structures of room impulse responses (IRs) at different positions in a 1:10 scale model hall. Continuous wavelet transformation (CWT) coefficients were calculated using mother wavelet functions of the Daubechies wavelet families and specular reflections along with their degrees of diffuseness were investigated from the IRs. In CWT analysis, the early specular reflections were detected by fining their similarities with mother wavelet at different scales. While these reflections were treated as “defects” or “singularities” that embedded in the Schroeder decay curve. In addition, the time difference of arrival (TDOA) was applied to localize the reflections using a cross correlation function for time delay estimation and direction finding of binaural room IRs. The spectral characteristics in terms of delay time were calculated by auto-correlation and interaural cross-correlation functions (ACF/IACF).
Bayesian parameter estimation of single- and double-layer micro-perforated panel absorbers
Authors: Schmitt Andrew , Xiang Ning , Fackler Cameron
Published: November 2013

Micro-perforated panel (MPP) absorbers have been widely accepted in applications as an efficient and clean sound-absorption solution providing extremely high, yet relatively narrow frequency band, acoustic absorption coefficients. Design for the custom acoustic performance of MPPs can be challenging for engineers and designers, however, due to the number of parameters making up the panel absorbers. This work examines the effects of the perforation rate, pore diameter, airspace depth, and panel thickness on the absorption profile of single- and double-layer MPP absorbers. A Bayesian inference framework is implemented in order to inversely determine parameter values and their uncertainties from experimentally measured acoustic absorption data of various MPP constructions of unknown parameters. This analysis also provides insight into the effects of each parameter on the acoustic performance as well as interdependence among the parameters.
Acoustics 101 for architects
Authors: Fay Michael W.
Published: November 2013

A presentation of acoustical terminology and concepts that relate directly to the design and construction of an architectural space, non-technical explanations, descriptions, and examples. Architectural acoustics can be defined as the study and application of acoustic principles as they are applied to the inside of a building or structure. Usually, these are buildings that will be used for a live performance or the presentation of other useful information. This paper is written with the architect in mind; to help define and explain some of the most basic concepts relating to architectural acoustics. In today's pro/commercial audio marketplace, architectural acoustics must play a significant role in the design process for any programmed meeting or entertainment space. This work puts essential terms and concepts into the hands of the architect, owner, or anyone else who would like to have a better understanding of this topic. Contents: What is Sound? Sound Propagation Three Acoustical Tools Where Does All the Unused Sound Go After it’s Been Heard? Audio Volume Changes—What Do the Numbers Mean? The Inverse Square Law Room Geometry—The Good, Bad, and Ugly Reverberation and Echo Speech Intelligibility Noise Internal vs External Noise Room Modes Variable Acoustics Psychoacoustics Conclusion.
History of applications of tags to study animal bioacoustics
Authors: Tyack Peter L.
Published: November 2013

I discuss the history of applications of tags to study animal bioacoustics, with an emphasis on toothed whales. My own interest in this topic was stimulated in the early 1980s by problems identifying which dolphin made a sound. Our inability to identify signaler and receiver hindered the study of communication among marine mammals. I discuss the evolution of devices and methods to solve this problem. The development of acoustic recording tags in the 1990s enabled the capacity to monitor what an animal hears at sea and how it responds. These tags form a critical enabler for field experiments on the relationship between acoustic exposure measured on the tag and behavioral responses, also often measured by the tag. Use of passive acoustic tags with echolocating animals has opened a new window on how toothed whales echolocate to find, approach, and capture prey, especially when the tags also include three-axis accelerometry and magnetometry to measure orientation and movement. The combination of these tags with passive acoustic monitoring provides a powerful method to improve localization, to estimate the three dimensional beampattern of sound production, and to estimate the absolute abundance of species that vocalize.
Acoustic time synchronization among tags on porpoises to observe their social relationships
Authors: Akamatsu Tomonari , Sakai Mai , Wang Ding , Wang Kexiong , Li Songhai
Published: November 2013

Observing and monitoring underwater social interactions of cetaceans is challenging. Because cetaceans spend most of their time underwater, it is important to monitor their underwater behavior individually. The finless porpoise is small and has no available natural identification marks that causes little knowledge of its sociality. Here we used acoustic datalogger to synchronize individual depth profile among individuals within a second. Acoustic and behavior tags were deployed on six free-ranging finless porpoises simultaneously and released in open water. Echolocation sounds were used as the trigger signal to synchronize the clock of all logging systems. Synchronous dives characterized by similar time-depth profile were used as an index of association. Two pairs tended to participate in long periods of synchronized diving more frequently than 13 other possible pairs, indicating that these four porpoises chose their social partners. Initiator and follower could be identified by precisely time synchronized data. The adult males tended to follow the immature female and juvenile male, respectively. However, the role of an initiator often changed within the pair during synchronized diving, and their body movements appeared to be non-agonistic.The time-synchronized bio-logging method was useful for observation of the social relationships of free-ranging aquatic animals.
Insights into a complex communication system from tagged bottlenose dolphins
Authors: Sayigh Laela , Janik Vincent , Jensen Frants , McHugh Katherine , Wells Randall , Tyack Peter
Published: November 2013

Since 2011, we have deployed 30 acoustic and movement logging DTAGs on long-term, multi-generational resident bottlenose dolphins in Sarasota Bay, Florida, for a total of approximately 140 h. Twenty-two tags were deployed simultaneously on pairs of associated individuals, allowing for greater resolution of individual vocal activity. Virtually all dolphins in the Sarasota Bay community are identifiable both visually and by means of their individually distinctive signature whistles. Tags were attached during brief capture-release health assessments, and behavioral observations of tagged individuals post-release continued for as long as possible. Tag data reveal unique insights into foraging behavior, including distinctive acoustic and movement patterns associated with particular foraging modes (e.g., “pinwheel feeding”). In addition to echolocation clicks and buzzes, several distinctive pulsed sounds were recorded on the tags. Whistle copying was observed 18 times in a preliminary analysis of approximately two hours of data, and at least one instance involved more than two dolphins producing the same whistle. Finally, we obtained evidence for at least one shared, stereotyped non-signature whistle. Combining extensive longitudinal information on individual dolphins with fine scale behavioral and acoustic data provides tremendous opportunities for describing and quantifying the complexity of the bottlenose dolphin communication system.
Tags, drifters, and Towfish: Using multiple recording platforms to characterize odontocete acoustic space
Authors: Mooney T. A. , Kaplan Maxwell B. , Baird Robin W. , Partan Jim
Published: November 2013

Bioacoustic tags can reveal novel information about the behavior and ecology of animals on which they are deployed. Yet tags are often placed off the animals’ acoustic axis, limiting some potential analyses. In order to broaden abilities to examine bioacoustic signals and behavior of several Hawaiian odontocetes we adapted recording methods to enhance data collection opportunities and free-field records. While bioacoustic DTAGs were deployed, we also used DMONs (digital acoustic recorders) in both a GPS-outfitted drifter buoy (Drifting Acoustic Wideband Gizmo = DAWG) and a Towfish around pantropical spotted dolphins (Sa), melon-headed whales (Pe), and short-finned pilot whales (Gm). Daytime tag recordings show Pe and Sa were limited to relatively shallow dives (< 50 m) but were relatively soniferous, whereas Gm made occasional deeper dives (to 700 m) and fewer individual calls. Group measures for Pe and Sa from the DAWG and Towfish revealed relatively high incidences of overlapping calls. Preliminary investigations of Pe whistles suggest some limited variation between Pe populations and considerable variability in individual call types. Such characterizations of call rates and variability support efforts to detect and classify odontocete calls. The different methods provided complementary means to collect substantial bioacoustic data on pelagic odontocetes for which few data exist.
Using acoustic tags to investigate sound exposure and effects on behavior in endangered killer whales (Orcinus orca)
Authors: Holt Marla M. , Hanson M. Bradley , Emmons Candice K. , Houghton Juliana , Giles Deborah , Baird Robin W. , Hogan Jeff
Published: November 2013

In this investigation, acoustic tags (DTAGs) allow us to better understand noise exposure and potential behavioral effects in endangered Southern Resident killer whales (SRKWs). Designated critical habit of SRKWs includes summer foraging areas where vessel traffic from commercial shipping, whale-watching, and other boating activities is common. Risk factors of population recovery include vessel and noise effects, and prey quality and availability. DTAGs, equipped with hydrophones and other sensors, are attached to individual whales to collect data on vocal and movement behavior, as well as their acoustic environment. Specific research goals include: (1) quantifying received noise levels in biologically relevant frequency ranges from tag data; (2) determining relationships between noise levels and detailed vessel variables obtained from precise geo-referenced vessel data collected concurrently; (3) investigating whale acoustic and movement behavior during different activities, including foraging, to understand sound use and behavior in specific biological and environmental contexts; and (4) determining potential effects of vessels and associated noise on behavior. This paper will describe the experimental approach taken, challenges faced, and results obtained from over 80 h of tag data. These data have been critical for addressing our research goals related to multiple population risk factors of endangered SRKWs.
Killers in the dark—Acoustic evidence for night-time predation by mammal-eating killer whales (Orcinus orca) in Alaska
Authors: Deecke Volker B. , Shapiro Ari D. , Miller Patrick J.
Published: November 2013

North Pacific killer whales that specialize on hunting marine mammals do not typically echolocate while searching for prey. This suggests that they detect prey by either relying on visual cues or listening for sounds generated by prey animals. If prey detection requires vision, hunting should be limited to the daylight hours. Documenting predation at night would therefore provide evidence supporting a passive listening hypothesis of prey detection. We used digital recording tags (DTAGs) to study the behavior of mammal-eating killer whales in Southeast Alaska. These tags recorded the underwater movements of the tagged individual and any sound emitted or received. Predation events were identified using distinctive sounds generated during prey capture and handling. We deployed 13 tags, of which 7 remained attached for at least part of the night. The majority of tags recorded night-time predation, even though nights were short (average of 4:18 h) during the study period. These findings show that mammal-eating killer whales can detect prey at night and thus suggest that passive listening is an important part of their hunting strategy. Acoustic data from digital recording tags can therefore provide valuable insights into the night-time activities and foraging behavior of killer whales and other marine mammals.
Characterizing dynamics of shear waves induced with acoustic radiation force impulse in histotripsy lesions for treatment feedback
Authors: Wang Tzu-Yin , Hall Timothy L. , Xu Zhen , Fowlkes J. Brian , Cain Charles A.
Published: November 2013

Histotripsy mechanically fractionates soft tissues into fluid-like homogenates that cannot support shear waves. We hypothesize that dynamics of shear waves excited from a histotripsy lesion using acoustic radiation force impulse (ARFI) change progressively during the fractionation process, and such change is related to the degree of tissue fractionation. To test this hypothesis, lesions with different degrees of fractionation were created in agar-graphite tissue mimicking phantoms and ex vivo kidneys with increasing numbers of histotripsy pulses (3-cycle 750- kHz ultrasound pulses at a peak negative/positive pressure of 17/108 MPa). The shear waves were excited by ARFI focused at the lesion center. The shear-induced temporal displacement profile was measured at a lateral location 10 mm offset to the lesion with M-mode imaging. Results showed significant changes in two characteristics: the peak-to-peak displacement decayed exponentially, and the relative time-to-peak displacement increased and saturated with increasing numbers of histotripsy pulses (N = 6). Correspondingly, the degree of tissues fractionation, as indicated by the percentage of structurally intact cell nuclei, decreased exponentially. Strong linear correlations existed between the two characteristics and the degree of tissue fractionation (R2 > 0.97). These results suggest that characteristics of shear waves induced in a histotripsy lesion may provide useful feedback for treatment outcomes.