bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropic inertial acoustic metamaterials for use in aqueous environments.
Authors: Martin Theodore , Nicholas Michael , Orris Gregory , Torrent Daniel , Sanchez-Dehesa José
Published: October 2010

The concept of using multiple scattering to create an effective anisotropic mass density/bulk moduli for a composite inertial metamaterial has been around for a few years. Designs for use in aqueous environments face several distinct challenges in comparison to designs useful for airborne applications. The main difficulties lie in that the types of sturdy material components with which an inertial metamaterial can be created are effectively limited to relative impedances of less than a few tens of times that of water. Simply put, the density of water and sound speed comprising the background wave propagation media are much larger than their gaseous counterparts, creating an upper bound on such systems. Further complications can arise from the fact that approximations typically used to describe the scattering elements in homogenized fluid-like systems for airborne applications can become inaccurate for aqueous environments. Within this context, we present the current state of our experimental verification and validation of a multiple scattering based gradient index lens constructed for frequencies lower than 20 kHz, as well as theoretical/numerical investigation into this and related phenomenon for an orthotropic metamaterial system in an aqueous environment and consider the implications on more complex 2- and 3-D inertial metamaterial systems for use therein. [Work supported by the Office of Naval Research.]
Experimental evaluation of membrane type acoustic metamaterial arrays.
Authors: Naify Christina J. , Chang Chia-Ming , McKnight Geoffery , Nutt Steve
Published: October 2010

Traditional acoustic treatments such as foam and fiber panels used for sound insulation in transportation applications typically perform poorly at low frequencies without costly addition of mass. Locally resonant acoustic metamaterials have demonstrated a single transmission loss (TL) peak of up to 500% over the acoustic mass law at frequencies as low as 100 Hz with minimal weight penalty. The frequency of the TL peak was tuned by adjusting various geometric properties of the structure including membrane material, mass magnitude, and membrane size. Limits to the practical applications of the single-cell structure resulted in the development of panels comprised of multiple mass-weighted membranes. Arrays of membrane-type metamaterials were fabricated and evaluated to examine their transmission loss and dynamic response under acoustic loading. Large membranes were divided using support frames to create individual cells of the metamaterial. Multiple TL peaks were achieved for the arrays by varying the mass magnitude attached to each cell of the array. In addition, membrane material variation kept the TL peak at low frequencies with reduction in the size of each cell in the array. Finally, dynamic analysis using a laser vibrometer was performed to understand the interaction between cells under acoustic loading.
Prosody production in spontaneous speech: Phonological encoding, phonetic variability, and the prosodic signature of individual speakers.
Authors: Cole Jennifer , Shattuck-Hufnagel Stefanie , Mo Yoonsook
Published: October 2010

We examine the prosodic variation in production with corpus and experimental speech materials. Prosodic transcription of spontaneous speech from the Buckeye corpus of American English (38 speakers, 54 excerpts, 11–55-s duration each) reveals striking inter-speaker variation in the frequency and distribution of prosodic prominences and boundaries, and in acoustic correlates (pitch, intensity, duration, and spectral measures). Inter-transcriber agreement rates also vary systematically across speakers, suggesting inter-speaker differences in the clarity/consistency of prosodic cues. To further explore variability in the phonological and phonetic expression of prosody while holding lexico-syntactic content constant across speakers, we conducted an auditory repetition experiment. Ten American English speakers listened to 32 excerpts (8–15 words each, 4 speakers) from the American English Map Task corpus and reproduced each utterance with the exact words and “in the way the speaker said them”, without text prompts. Preliminary results from prosodic transcription and acoustic analysis show reliable replication of the phonological structures locating prosodic prominences and phrase boundaries, but with variation in the pitch melody and other phonetic details of the prosodic features. These findings shed light on the mapping between the phonological encoding and the acoustic expression of prosodic features, and highlight those acoustic parameters that identify the prosodic signature of individual speakers.
The Edinburgh Speech Production Facility’s articulatory corpus of spontaneous dialogue.
Authors: Turk Alice , Scobbie James , Geng Christian , Macmartin Cedric , Bard Ellen , Campbell Barry , Dickie Catherine , Dubourg Eddie , Hardcastle Bill , Hoole Phil , Kanaida Evia , Lickley Robin , Nakai Satsuki , Pouplier Marianne , King Simon , Renals Steve , Richmond Korin , Schaeffler Sonja , Wiegand Ronnie , White Kevin , Wrench Alan
Published: October 2010

The EPSRC-funded Edinburgh Speech Production is built around two synchronized Carstens AG500 electromagnetic articulographs (EMAs) in order to capture articulatory/acoustic data from spontaneous dialogue. An initial articulatory corpus was designed with two aims. The first was to elicit a range of speech styles/registers from speakers, and therefore provide an alternative to fully scripted corpora. The second was to extend the corpus beyond monologue, by using tasks that promote natural discourse and interaction. A subsidiary driver was to use dialects from outwith North America: dialogues paired up a Scottish English and a Southern British English speaker. Tasks. Monologue: Story reading of “Comma Gets a Cure” [Honorof et al. (2000)], lexical sets [Wells (1982)], spontaneous story telling, diadochokinetic tasks. Dialogue: Map tasks [Anderson et al. (1991)], “Spot the Difference” picture tasks [Bradlow et al. (2007)], story-recall. Shadowing of the spontaneous story telling by the second participant. Each dialogue session includes approximately 30 min of speech, and there are acoustics-only baseline materials. We will introduce the corpus and highlight the role of articulatory production data in helping provide a fuller understanding of various spontaneous speech phenomena by presenting examples of naturally occurring covert speech errors, accent accommodation, turn taking negotiation, and shadowing.
Clarifications in spontaneous speech under three different adverse communicative situations.
Authors: Baker Rachel , Hazan Valerie
Published: October 2010

Difficult communicative situations requiring clear speech are common. This study investigated whether (a) clear speech elicited by instructing talkers to read sentences clearly reflects clarifications made by talkers in spontaneous speech with communicative intent and (b) talkers modulate their clear speech according to the type of adversity under which communication takes place. Casual and clear speech from 40 Southern British English talkers was elicited in dialogues recorded while two talkers engaged in “spot the difference” picture tasks, based on the Diapix task of Bradlow and collaborators. Three types of “communication barrier” were used to elicit clear speech: in the VOC condition, one talker heard the other via a three-channel vocoder; in the NOISE condition, one person heard the other with simultaneous babble noise; in the L2 condition one talker was a low-proficiency non-native speaker. Read clear speech showed more extreme changes in median F0, F0 range and speaking rate than spontaneous clear speech. Greater changes were made to speaking rate and vowel space in the VOC than the L2 condition, while greater changes in F0 and mean energy were made in the NOISE than the VOC condition, suggesting that talkers clarify their speech according to listeners’ needs. [Work funded by ESRC project no. RES-062-23-0681.]
Considering the storage, management, and processing of spontaneous speech corpora: New methods and new findings.
Authors: Kendall Tyler
Published: October 2010

Recordings of speech, both spontaneous and nonspontaneous, comprise the backbone of acoustic phonetic, speech science, and much general linguistic research. The creation of these speech recordings (e.g., recording equipment and its use) and their analysis (e.g., appropriate statistical methods) tend to be thoroughly treated in methodology sections of papers and in specialized methodology textbooks. However, the storage, management, and preservation of these resources are rarely discussed in the academic literature, though these practices influence both the short-term and long-term usability of these resources. This talk addresses the related questions of how we might best manage large and growing collections of audio data and how we can leverage new technologies so that our data archives are not just usable, but maximally useful. Examples are provided from two web-based archiving projects, the Sociolinguistic Archive and Analysis Project (SLAAP) and the Online Speech/Corpora Archive and Analysis Resource, which feature organization and analysis tools that enhance the overall usefulness of the archived recordings. To exemplify some substantive outcomes of these projects, findings from a corpus sociophonetic study of speech rate and pause variation in American English, made possible by SLAAP’s software, are also discussed.
An overview of physics-based signal and information processing in sonar.
Authors: Abraham Douglas
Published: October 2010

Sonar systems are usually designed for the purposes of detection, classification, localization, and tracking (DCLT) objects under water. DCLT is accomplished through signal and information processing applied to the sonar’s sensor data. Physics exploitable in sonar DCLT enter either through the object of interest’s sound generation or scattering or through propagation from and to the sonar. In general, the former is exploited in classification and the latter in localization and tracking. In order to highlight key principles and issues in physics-based signal and information processing, examples of DCLT algorithms exploiting physics will be presented from each of the major processing tasks. There are a plethora of examples, ranging from those coincident to the unadulterated signal-processing approach to those enabling performance unachievable without exploitation of the specific physics. A metric of equal importance to performance is that of robustness to assumed models and information. Ideally, algorithms are designed to maximize both performance and robustness to uncertainty or inaccuracy. However, it is more common to see performance and robustness inversely related to each other. The talk will conclude with observations on potential open areas for exploiting physics in sonar DCLT. [Work sponsored by ONR under Contract no. N00014-09-C-0318.]
Propagation equations for non-stationary noise in waveguides.
Authors: Cohen Leon
Published: October 2010

We discuss how to transform wave equations into phase-space equations and apply the method to the time-varying autocorrelation function and to time-varying spectral distributions. We give a number of examples and argue that the phase-space equation is often more revealing than the original wave equation. We derive a successive approximation scheme for propagation in media that has dispersion and attenuation. The methods developed are applied to the propagation of noise fields in wave guides wherein we obtain relations for how the non-stationary autocorrelation function changes in position and time. We also show that the evolution of the statistics toward equilibrium can be seen in a much clearer way when the problem is formulated in phase-space. In addition, we show that one can obtain propagation equations for the amplitude and phase separately.
Potential for extraction of scatterer and waveguide characteristics from reverberation spectrograms.
Authors: LePage Kevin D.
Published: October 2010

Coherent structure in the spectrograms of broadband reverberation in the mid frequency regime has been measured at various sites by various researchers. Recently, very broadband data collected over three and a half octaves on the Malta Plateau during the Clutter 09 experiment conducted by the NATO Undersea Research Centre show very clearly the striation structure of interest. In this paper, the theory of why the striations appear in the spectrograms of the reverberation is briefly reviewed, and the extraction of channel and scatterer information from the time-frequency content of the signal is explored using holomorphic processing. To constrain these studies, we exploit the availability of broadband reverberation models which contain all the features of the data, are noise free and have zero uncertainty, and have known waveguide and scatterer characteristics to compare with the extracted information. The Clutter 09 data are also evaluated using the method, and the resolution and robustness of the approach are discussed.
Passive sonar classification using time-frequency domain “features”.
Authors: Sell Alexander W. , Culver R. Lee
Published: October 2010

Success in classifying passive sonar signals depends heavily on understanding the source characteristics and the physics of propagation and scattering in the ocean environment. Passive sonar signals are typically analyzed using bearing versus time records (BTRs) and time versus frequency displays (lofargrams). Much research has been devoted to studying the relationship between features in the time-frequency domain (i.e., lofargrams) and the range, depth, speed, and other aspects of an acoustic source. For example, striations in time-frequency domain are known to be related to broadband excitation of resonances in the shallow water waveguide. The slope of the striations can be predicted using the so-called waveguide invariant. Other waveguide-dependent resonance features can be predicted with some knowledge of the environment. While studying data from a September 2007 shallow water acoustic transmission test, performed along the continental shelf off the coast of southeast Florida, we noted a “bathtub phenomenon” in lofargrams encompassing the closest point of approach of two surface ships. The relationship between these features and the characteristics of the surface ship source is the subject of this talk. [Work supported by ONR Undersea Signal Processing.]
Choosing array processor weights for observing waveguide-invariant intensity striations.
Authors: Cockrell Kevin L. , Schmidt Henrik , Preisig James C.
Published: October 2010

It is well known that a horizontal line array (HLA) can be used to observe a planewave signal from one source while rejecting noise from other sources. This talk discusses the selection of HLA processor weights when the goal is to observe waveguide invariant striations from one source while rejecting noise from other sources. It is shown that the array weights commonly used for planewave beamforming, such as uniform weights, can have the unintended effect of suppressing some the desired striations. Examples will be given demonstrating this effect. [Work supported by ONR N00014-08-1-0013]
Environmentally tolerant waveguide-invariant target depth classification for active sonar.
Authors: Goldhahn Ryan , Nielson Peter , Krolik Jeffrey
Published: October 2010

Shallow-water environments produce active sonar returns with many target-like returns from bottom clutter. Scatterer depth classification methods which can discriminate bottom clutter from water column targets are thus critical for controlling false alarms. In recent work, the waveguide invariant (WI) property of shallow-water channels has been used to obtain multiple snapshots of frequency-domain target return data from a single active sonar ping. These snapshots are, in turn, used to estimate a waveguide invariant spectral density matrix (WI-SDM), which can serve as a basis for depth classification. One method employing the WI-SDM performs minimum variance filtering (MVF) matched to depth-dependent signal replicas derived from a normal mode model. While MVF is capable of depth classification when the environment is known, it is sensitive to mismatch when the channel parameters are uncertain. In this paper, robustness of the WI MVF to mismatch is achieved by using environmental perturbation constraints derived from a WI-SDM for the signal averaged over the uncertain channel parameters. Simulated and real data results are presented from the CLUTTER-09 experiment in the Mediterranean Sea. [Work sponsored by ONR.]
Ceiling plenum design: Laboratory testing of ceiling/plenum systems for ceiling attenuation class.
Authors: Roy Kenneth P. , Good Kenneth W.
Published: October 2010

Any acoustic testing laboratory that performs the ASTM E1414 testing of ceiling attenuation class ceiling system will have experimented with a few odd cases and learned a few interesting “rules of thumb.” The Armstrong World Industries Acoustic Testing Laboratory in Lancaster, PA, has certainly had its share of those, and has learned a few things about materials and systems along the way. We would like to share these understanding about ceiling materials, grid systems, plenum stuff, etc. Test data…that is what it is all about.
Use of air pressure dampening in impact noise control.
Authors: Keene James , LoVerde John
Published: October 2010

Since the 1980s, entangled net resilient mats have been used to effectively control impact noise in multi-family dwellings. The thickness of the resilient mat was modified to provide higher levels of acoustical isolation performance, and structural underlayments were used to instal over the resilient matting to provide sufficient support for finished flooring. Other products have been developed that work similarly, including rubber, cardboard, and insulation devices, varying the resilience, thickness, and airspace. Recently through engineering of what is commonly called a “high loft” fabric integrated into an entangled net resilient mat, a composite flooring product has been developed that, to date, changes the acoustical performance of standard thickness entangled net resilient mat devices to an enhanced level. This highly compressible fabric makes a 0.25-in. device resilient mat perform at a greater level than a typical 0.375-in.-thick resilient mat device. The addition of this fabric allows for the consistent, luxury performance in one product with typical 1.0-in. underlayment systems. This presentation is an explanation of the physics development behind the design and provides the group with some preliminary testing of different materials objective comparative acoustical tests to show the differences between conventional resilient mattings and the new composite material.
Predicting isolation efficiency using the prognosis method.
Authors: D’Antonio Peter , Vanstraelen Michael
Published: October 2010

A method will be described to estimate the transmission loss (TL) of a floating floor separated by an elastomer from a structural concrete floor, using the prognosis method. The system resonance is determined by the two masses and the combined stiffness of the elastomer and the constrained air. At low frequencies, the TL curve has a slope of 6 dB/octave based on the mass of the double system. At the resonant frequency (fr) of the system, the TL is strongly reduced. Above fr, the isolation increases rapidly at a rate of 18 dB/octave until the upper limit of 12 dB/octave is reached, due to the sum of the isolation of the two masses. Several examples of different floating floor options, using MS Excel software program, will be provided to illustrate the effects of the floor masses, the fr of the isolator, the stiffness of the constrained air layer, and flanking.
Software tools for visual and acoustic real time tracking of marine mammals.
Authors: D’Amico Angela , Kyburg Christopher , Carlson Rowena
Published: October 2010

The Whale Identification, Logging, and Display (WILD) software system was developed to provide researchers tools to integrate sightings of marine mammals by trained visual observers, detections by passive acoustic arrays and other hydrophone systems, and positions of research vessels on a graphical display in real time onboard a research vessel. The WILD system was used successfully on the MED 09 sea trial in July–September 2009 aboard the NATO Research Vessel Alliance. During the cruise, all observations were transmitted over the ship’s network using custom data sentences developed by the researchers based on the National Marine Electronics Association 183 standard. The custom software extended ArcMap by allowing it to read and parse these sentences and update the maps in real time. This allowed scientists, biologists, and the ship’s crew to tightly coordinate their efforts, permitting the best possible data collection and observation of the animals. The research provides scientists with better estimates of whale populations and their behavior in the Western Mediterranean Sea. [Work supported by the Office of Naval Research.]
Management of acoustic detections via the Tethys database system.
Authors: Roch Marie A. , Hildebrand John A.
Published: October 2010

Driven by advances in consumer electronics and pattern recognition algorithms, passive acoustic monitoring has become a common tool for monitoring the vocal activity of animals. The increased acoustic effort to detect and categorize animal vocalizations has resulted in a need to organize acoustic detections and provide the ability to integrate other data sources. This paper presents Tethys, a prototype hierarchical database designed to provide flexible data handling in order to meet the needs of the bioacoustics community. Tethys provides mechanisms to easily adapt to changes in metadata structure resulting from equipment and algorithm evolution. It also provides an extension mechanism to permit the integration of other databases in a transparent manner, making querying alternative data sources (e.g., environmental data) appear like native queries. Tethys has the ability to communicate with multiple languages such as Matlab, Java, C++, and Python over secured network connections, and we show example applications where Tethys interfaces with the Horizons ephemeris service (NASA Jet Propulsion Laboratory) and Google Earth. [Work sponsored by ONR.]
A review of fixed autonomous underwater recorders.
Authors: Sousa-Lima Renata S. , Norris Thomas F. , Oswald Julie N.
Published: October 2010

Autonomous underwater recorders (ARs) are fixed passive acoustic electronic systems that acquire and store acoustic data internally (i.e., without a cable or radio link to a receiving station). They are deployed semi-permanently underwater (via a mooring, buoy, or resting on the sea-floor) and must be retrieved after the deployment period to access the data. ARs are capable of monitoring and recording underwater sounds over a wide range of spatial and temporal scales. As part of a Joint Oil & Gas Industry Program on Sound and Marine Life (JIP) sponsored effort, we reviewed over 30 ARs that are available for recording marine mammal sounds. They varied greatly in price and capabilities, from small hand-deployable units for detecting dolphin and porpoise clicks in shallow water to large units that can be deployed in deep water and record wide frequency bands for long durations. Considerations to weigh when selecting which device to use include price, longevity and depth of deployment, area to be monitored, and, most importantly, the bandwidth and the characteristics of sounds to be monitored (i.e., marine mammal call types and noise sources).
A review of computer-based methods for the automated detection, extraction, and classification of marine mammal sounds.
Authors: Oswald Julie N. , Norris Thomas F. , Sousa-Lima Renata S.
Published: October 2010

Passive acoustic systems used to study and monitor marine mammals generate enormous datasets which are costly and time-consuming to analyze. As part of a Joint Industry Programme sponsored effort, we reviewed automated and semi-automated methods and software packages available to detect, extract, and classify marine mammal sounds; identified gaps in capabilities and knowledge; and suggested ways forward. Because of the variability in marine mammal sounds, no single method is effective for all species. While spectrogram correlation works well for stereotyped calls, more general methods like band-limited threshold detection are more effective for variable sounds. Feature extraction is a rapidly evolving field, but a reliable, automated method has yet to be successfully implemented into existing software. A major gap in our capabilities is the ability to reliably detect and classify the highly variable signals produced by some species. The development of effective, efficient, and standardized methods applicable to many species will require large, validated datasets. The acquisition, maintenance, and availability of such datasets will entail concerted, collaborative efforts. Development of common datasets and organization of workshops that focus on furthering detection, extraction, and classification methods are two ways to address these important issues in the automated analysis of marine mammal sounds.
Correlating microvessel permeability directly with ultrasound-activated microbubble dynamics.
Authors: Chen Hong , Brayman Andrew A. , Evan Andrew P. , Matula Thomas J.
Published: October 2010

Ultrasonically activated microbubbles are promising candidates for targeted therapeutic applications such as drug and gene delivery. Understanding vascular permeability is thus important. In this study, ultra high-speed microphotography was used to directly visualize the dynamics of microbubbles in microvessels, under the excitation of ultrasound pulses with a duration time of about 2 μs, a center frequency of 1 MHz, and peak negative pressures (PNPs) between 0.8 and 7.2 MPa. Correlated vascular permeability was examined by imaging extravasation of bubbles from the vessels and by looking at the treated region histologically and under transmission electron microscopy. Local vessel distention and invagination caused by microbubble oscillations and liquid jet impinging on the vessel wall all appear to contribute to enhanced permeability for microvessels with diameters < 20 μm and insonation PNP > 4 MPa. Vascular permeation was also observed in larger vessels. However, in these cases vessel invagination was greater than distention in more than 80% of the cases and liquid jets always directed away from the vessel wall. We thus hypothesize that the dominant mechanisms for microbubble-induced permeation of smaller microvessels are different from larger microvessels. [Work supported by NIH EB000350 and AR053652.]
Models for the dynamical interaction of bubbles and blood vessels.
Authors: Hamilton Mark F. , Hay Todd A. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Chen Hong , Kreider Wayne , Bailey Michael R. , Matula Thomas J.
Published: October 2010

An understanding of ultrasound contrast agent (UCA) microbubble dynamics in blood vessels is important for ultrasound imaging and therapy. Recent photographs of UCAs excited by high-intensity ultrasound pulses in ex vivo vessels reveal unexpected phenomena. Strong bubble pulsations near the vessel wall induce contraction of the vessel that remains after bubble motion has subsided. Also, the bubble often translates toward the center of the vessel while forming a jet in the direction of translation. Three models describing the dynamics of a bubble in channels formed by elastic walls have been developed in an attempt to understand these phenomena. Two of the models describe a bubble between parallel elastic layers immersed in a viscous fluid. One incorporates bubble translation and aspherical bubble shape, which accounts for the onset of jetting, but is limited to incompressible fluids and layers with small shear moduli. The other accounts for fluid compressibility and arbitrary layer viscoelasticity, but is limited to stationary spherical bubbles. The third model is for a spherical bubble at an arbitrary but fixed location in a cylindrical viscoelastic tube. Comparisons between observed behavior and theoretical predictions will be presented and the relative merits of each model discussed. [Work supported by NIH DK070618.]
Determination of optimal ultrasound parameters for ex vivo sonothrombolysis.
Authors: Ivancevich Nikolas M. , Haworth Kevin J. , Hitchcock Kathryn E. , Holland Christy K.
Published: October 2010

Stable cavitation is correlated with thrombolytic efficacy for recombinant tissue plasminogen activator (rt-PA) mediated thrombolysis. An infusion of Definity® nucleated, promoted, and sustained stable cavitation in an ex vivo porcine carotid model exposed to 120-kHz continuous wave ultrasound. The optimal ultrasound pressure amplitude and the durations of active and quiescent periods were determined to maximize stable cavitation. Oxygenated porcine plasma with Definity® (0.31 μL/mL) and rt-PA (3.15 μL/mL) flowed through excised carotids loaded with whole-blood clots exposed to 120-kHz ultrasound and monitored with a 2.25-MHz passive cavitation detector. Using ultraharmonic and broadband emissions to quantify stable and inertial cavitation, respectively, intraluminal ultrasound-induced bubble activity was monitored in three vessels at four acoustic pressures. Thirty-minute treatment trials were simulated to determine the optimal acoustic pressure amplitude (0.44 MPa peak-to-peak) and ultrasound duration (8.5 s) to promote stable cavitation. A fixed quiescent period (19.5 s) allowed fresh Definity® to nucleate episodes of bubble activity. Clots exposed to this ultrasound scheme, Definity®, and rt-PA showed an average ultraharmonic energy of 1.0×10−1 V2 and an average broadband energy of 3.7×10−4 V2, compared to 4.5×10−5 and 1.8×10−5 V2, respectively, with ultrasound without Definity® and 4.3×10−6 and 2.4×10−6 V2 without ultrasound or Definity®. [Work supported by NIH 2RO1 NS047603 and a grant from the University of Cincinnati Neuroscience Institute.]
Green’s function for a volume source in a viscoelastic cylindrical tube.
Authors: Zabolotskaya Evgenia A. , Ilinskii Yurii A. , Hay Todd A. , Hamilton Mark F.
Published: October 2010

A model based on Green’s functions that has been reported at previous meetings describes the field produced by a volumetric source in a bounded viscoelastic medium. Proposed applications of this model include scattering of sound in biological media and by objects buried in soil. The model was also adapted to study acoustically driven bubble pulsations near the surface of a viscoelastic medium, including calculation of the stress and strain in the medium. The methodology is generalized here to include cylindrical tubes. The Green’s function is obtained for a volumetric source at an arbitrary location in a viscoelastic or viscous fluid-filled cylindrical tube. All modes of propagation in the elastic tube are taken into account as well as waves reflected from the tube wall. The Green’s function is expanded both as a Fourier integral with respect to the axial coordinate and as a Fourier series with respect to the polar angle. Amplitudes of the Fourier coefficients are determined by boundary conditions for displacements and stresses at the tube wall and by matching conditions on the cylindrical surface containing the source. The Green’s function is obtained in closed form and expressed through Hankel functions. [Work supported by NIH DK070618.]
Are electrocardiogram premature complexes induced by ultrasonic cavitation biomarkers for cardiomyocyte necrosis?
Authors: Miller Douglas L. , Dou Chunyan , Lucchesi Benedict R.
Published: October 2010

The objective of this study was to explore the relationship between lethal cardiomyocyte injury and arrhythmia induced by ultrasonic cavitation in the myocardium. Anesthesized rats were exposed in a heated water bath to 1.55-MHz focused ultrasound aimed at the heart with 2-ms bursts triggered at end systole during Definity (Lantheus Medical Imaging, Inc., N. Billerica, MA) contrast agent infusion. Premature complexes (PCs) where detected in electrocardiograph recordings, and Evans blue stained cardiomyocytes were scored in samples taken the next day. With 0.1 μl/kg/min infusion for 5 min, both effects increased strongly with increasing peak rarefactional pressure amplitude. At 8 MPa, statistically significant effects were found for no agent infusion relative to sham tests, indicating nucleation by naturally occurring nuclei. At 2 MPa, significant bioeffects were seen for 10, 1, and 0.1 μl/kg/min infusion but not for 0.01 μl/kg/min, which indicated a problematic nucleation. The numbers of PCs showed an exponential rise to maximum (r2=0.88) for increasing numbers of stained cells with 4.5 stained cells per PC in the linear range. These results suggest a casual relationship between lethal cardiomyocyte injury and PCs induced by cavitation nucleation during cardiac ultrasound exposure. [Work supported by NIH Grant EB000338.]
Subsurface characterization of microelectronics using high-frequency contact ultrasound.
Authors: Dieckman Eric A. , Hinders Mark , Stevens Jonathan
Published: October 2010

The goal of this project was to develop and demonstrate a prototype system for characterizing subsurface features in microelectronic components using high-frequency pulse-echo ultrasound. Of particular interest are suspected counterfeit router components, which need to be inspected quickly and nondestructively with portable equipment that does not require extensive training to operate. Although ultrasound in the 100 MHz frequency range routinely images the relevant subsurface features in microelectronic components, scanning acoustic microscopes are neither portable nor inexpensive, and they require the component to be submerged in a bath of coupling water. Our alternative approach was a custom-designed probe which uses direct contact with the component surface and does not employ water for coupling. Also, rather than high-precision computer-controlled scanning to produce images, the pulse-echo waveforms are processed using our discrete wavelet fingerprinting algorithm. This maps out the subsurface layers and interfaces and finds differences from nominal values that indicate that the part is flawed or counterfeit.
A hydrophone based on the piezoelectric gate of field effect transistor for deep-sea application in low-frequency range.
Authors: Sung Min , Shin Kumjae , Moon Wonkyu
Published: October 2010

A hydrophone based on the piezoelectric gate of field effect transistor(FET) for deep-sea application in the low-frequency range (10 Hz–20 kHz) was designed. The basic structure was piezoelectric thickness mode, which was directly applied on the gate area of a field effect transistor. Several types of sensors which used PVDF film integrated with FET have been reported. They have sensitivity limit in the low-frequency range due to stray capacitance by extended electrodes and low coupling coefficient of PVDF film. To achieve high sensitivity, a piezoelectric ceramic was directly applied to the gate area of the FET, which resulted in decreased effect of stray capacitance. Depletion mode FET with large gate area was adopted to realize high transconductance in the operation voltage range of the piezoelectric ceramic. The head mass structure, which was motivated by the Tonpilz structure, for both sound pressure amplification and prestress was placed between the clamped diaphragm and the piezoelectric ceramic. To develop the endurance for the high hydrostatic pressure in deep-sea, oil backing on the backside of the diaphragm was proposed. The parametric study based on the traditional FET model was performed in the design procedure. The comparison of simulation and experiment will be presented. [Research supported by MRCnd.]
Fields everywhere.
Authors: Ermann Michael , Vernon Mitzi , Jaramillo Ana , Chris Barnobi , Joseph Han
Published: October 2010

This proposed project aims to define science education as architects might define science education. There are values associated with points in space, those values can be mapped to generate a field, and those fields can have meaning. These values might be light levels, wind speeds, carpet pile heights, or sound pressure levels; when mapped, values might tell of a shadow, an approaching cold front, the former location of a piece of furniture on a carpet, or sound propagation. By allowing for a spatial and immersive science museum exhibit dedicated to sound propagation, frequency, and localization, this project aims to make plain the invisible nature of sound. Authenticity of phenomena is important to this endeavor. The points in space envisioned are not mathematical representations on a Cartesian grid, but real points in real space among and in between the museum visitors. Indeed, nothing in the proposed exhibit is simulated at all: patrons can experience the speed, propagation, frequency, and localization of sound in real time and real space. It is hoped that moving beyond the normative regime of kiosks simulating phenomena, and into a realm that is spatial, museum goers can better take ownership of the scientific content.
Development of an educational impedance tube: Experimental vibroacoustic characterization.
Authors: Melo Noé , Morais Marcus Vinícius , Nunes Maria Alzira , Oliveira Alessandro
Published: October 2010

One of the great difficulties encountered by designers who work with room acoustics is to know the absorption coefficient of the material to be employed in the project. The tube wave, also known as impedance tube, is a device which determines this coefficient and also determines the acoustic impedance of materials. These values are essential for choosing products that best fit the needs of an acoustic treatment project, either indoors, machinery, pipes, or mufflers. This paper presents the first studies to construction and characterization of an educational impedance tube (Kundt’s tube) called TIGaD (demonstrative impedance tube of the Faculty at Gama). In this first phase we will present a dimensional study of the tube, its construction details, an experimental analysis of its vibroacoustic characteristics, and, finally, its limitations in frequency range. This project belongs to the educational area since this experimental apparatus is being developed to equip the laboratory of acoustics and vibration (NVH Gama). The aim is to obtain low-cost equipment which makes possible the study of the various acoustic phenomena such as absorption, reflection, impedance, and further demonstration of plane waves and the determination of the speed of sound.
Subjective and physical experiments related to the tuning of classical guitars.
Authors: Orduña-Bustamante Felipe , Fernández del Castillo Gómez Francisco , Martínez Montejo Erika Enedina , Contreras Tello Humberto
Published: October 2010

The subject of tuning the classical guitar is discussed in the light of subjective experiments during which guitarists tuned a classical guitar using different tuning methods. Tones of the six open strings were recorded after each tuning session, and the perceived musical pitch was estimated using a psychoacoustically based pitch detection algorithm. Also, the input mechanical mobility was measured at the top plate bridge, at the nut bridge, and at all the frets. Frequency shifts due to string-body coupling were estimated for the frequency components of all possible (open and fretted) guitar tones, and perceived musical pitch was also estimated for these tones. Results are presented of tuning accuracy and variability for individual guitarists as well as among different guitarists. Also, estimates are presented of overall guitar tuning accuracy, depending on string-body coupling, fretted-tone over-tension, tuning method, and other factors.
Research on the acoustics of the guitar at the National Autonomous University of Mexico.
Authors: Ruiz-Boullosa Ricardo
Published: October 2010

The research on the acoustics of the guitar has had an interesting though brief history that began more or less in the 1960s. The results spread over a broad range of subjects, but is on the main focused in the lower modes of the guitar. Work being done now includes such topics as visualization of modes of vibration, radiation, etc., by the use of FEM and BEM methods. Lines of investigation that have some bearing on the sound of the guitar remain to be made. Tentative initial work on several topics is presented that have been undertaken in the acoustics laboratory at the National Autonomous University of Mexico. These include ways to measure the problems in tuning, the contribution of the neck to the radiation, the importance of high frequencies and modes of vibration on the sound of the guitar, the influence of the bridge design on the vibration and radiation of the top plate, and the influence of factors such as humidity. Some of these experimental lines, and others, could further expand the horizon of the acoustics of the guitar.
Evaluating design modifications in classical guitars.
Authors: Richardson Bernard
Published: October 2010

The structure and musical usage of the classical guitar has changed considerably over its long history and the instrument still continues to develop. Major the changes in construction of guitars in the latter part of the nineteenth century and changes in their playing style helped establish the classical guitar as a serious solo instrument, which still holds considerable prominence today. Many makers and players strive to “improve” the instrument, but their objectives are rarely clearly defined or the overall consequences of specific changes are misunderstood. This paper will try to establish an objective framework for establishing what constitutes the sound of a guitar and how that sound may be modified by changes in the design or construction of the instrument or through the use of different materials. It will bring together objective experimental and theoretical work on the structural vibrations of guitars and acoustical radiation with subjective psychoacoustical evaluation of real and synthetic sound signals with the aim of helping to answer the many questions posed by guitar makers.
Noise pollution problem in Mexico City.
Authors: Menchaca Garcia Felipe Rolando
Published: October 2010

Noise pollution in Mexico City is not a solved problem yet. In 1976 a national regulation was issued to prevent and reduce noise emitted by fixed and mobile sources, but it has not been implemented. This paper analyzes the reasons why noise pollution for Mexico citizen’s welfare is not the main concern, why regulations have not been applied, and what are the results of absence of attention to this problem. The impact of Mexico City Airport, main roads, and construction practices are unknown and has to be studied and reflected in regulations and government policies. Recommendations of this paper include these main aspects of the problem.
A comparative study of traffic noise modeling software.
Authors: Lin Robin , Russert Jeffrey , Walsh Daniel , Chéenne Dominique
Published: October 2010

CADNAA, SOUNDPLAN, and TNM are three industry-standard software programs used for road traffic noise modeling. These programs allow for the calculation and mapping of predicted sound levels over selected areas or at specific locations from a user-generated model comprised of sound sources and physical elements such as roads, buildings, etc., that define the environment. CADNAA and SOUNDPLAN also allow the user to select the standard defining the method of calculation. While many studies have been conducted to validate each of the three programs against specific test data, little research is available to compare the three together against a common set of test results. This study compares calculated sound levels in CADNAA 3.7, SOUNDPLAN 7.0, and TNM 2.5 against actual traffic noise levels acquired at nine locations across three sites, each site offering a different level of complexity in terms of modeling the environment. Models were kept highly similar in all three programs and calculation methods used both the FHWA and RLS-90 standards. Results show that no single program was consistently accurate when using either standard, and also highlights the strengths and weaknesses of the two standards.
Road noise mapping of Medellíńs downtown: Experiences, analysis of different calculation’s methods, and noise prediction software.
Authors: Murillo Gmez Diego Mauricio , Echeverri Londoño Carlos Alberto , Valencia Hernandez Germán Mauricio
Published: October 2010

In this paper we will present the development of road noise map in the downtown of Medellin City through the implementation of predictive software. For the construction of noise mapping, the results obtained using the calculation’s French method (NMPB) and German method (RLS 90) were compared. The prediction process was carried out using two different softwares (SOUNDPLAN and CADNAA) for the purpose of analyzing the differences in the programs and the resulting levels. Finally, noise measurements were made in order to validate the prediction.
Noise mapping: A comparison of predicted and measured levels.
Authors: Ryherd Steven R. , Ortkiese Tina M. , Cunefare Kenneth A.
Published: October 2010

In the United States, there are no national regulations requiring noise mapping in cities, and the noise mapping that is conducted is a consequence of local planning and policy bodies responding to or anticipating public demand. The production of oil and natural gas in urban environments has caused local governments surrounding Shreveport, LA, to utilize noise mapping and field measurements to assist in the development of a new noise ordinance. Over 1800 square miles surrounding the city was mapped considering air, rail, and road noise sources. Ten, multi-day measurement locations were strategically selected within the model area. A comparison of predicted and measured sound pressure levels is presented for consideration of future noise mapping methods and procedures.
Resonance spectroscopy: Time versus frequency and open versus closed systems.
Authors: Scales John A. , Smith Martin L.
Published: October 2010

The existence of resonance in any system derives from the presence of periodic wave propagation. Such periodicities can exist in closed systems [traditional resonance ultrasound spectroscopy (RUS)] or open systems (e.g., lasers), and they can be analyzed either in the time or frequency domain. From this broader perspective we can see that diverse techniques such as RUS, coda wave interferometry, diffuse wave spectroscopy, cavity ring-down spectroscopy, cavity perturbation, etc., share many common physical principles: propagating energy is trapped, at least temporarily, and allowed to repeatedly sample a medium. It is this repeated sampling that gives spectroscopy and interferometry their great sensitivity. In this paper we will show a number of examples of RUS or RUS-like techniques applied to the characterization of materials in the laboratory. Sometimes the waves will be mechanical and sometimes they will be electromagnetic, but the unity of the physical principles involved allow us to apply the lessons learned from RUS to a wide range of problems.