bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear flow-structure coupling in a mechanical model of the vocal folds and the subglottal system.
Authors: Howe Michael S. , McGowan Richard S.
Published: October 2013

An analysis is made of the nonlinear interaction between flow in a mechanical model of the subglottal vocal tract and a model of the vocal folds. The mean flow through the system is produced by a “lung cavity” that is assumed to be steadily contracting. The lungs are connected to a subglottal tube of length L. The model for the vocal folds is at the other end of the subglottal tube. This model is a simple, self-exciting single-mass mathematical model of the vocal folds used to investigate the sound generated within the subglottal domain and the unsteady volume flux from the glottis. In the case when the absorption of sound by the lungs is presumed small and when the subglottal tube behaves as an open ended resonator (when L is as large as half the acoustic wavelength) a mild increase in volume flux is predicted. However, the strong appearance of second harmonics of the acoustic field is predicted at intermediate lengths, when L is roughly a quarter of the acoustic wavelength. In the cases of large lung damping, however, only modest changes in volume flux are predicted to appear. [Work supported by DC-009229 to UCLA under subcontract.]
Vocal inharmonicity analysis: A promising approach for acoustic screening for dysphonia.
Authors: Matteson Samuel , Lu Fang-Ling
Published: October 2013

In the United States, 6.8% of men, women, and children report voice problems currently, while during their lifetime ca. 29% will complain of some dysphonia, often due to pathologies of the vocal folds. The authors (a physicist and a speech pathologist) describe an interdisciplinary approach that exhibits promise for detecting physiological abnormalities of the vocal folds from a spectral analysis of the overtone series of spoken tokens. This preliminary investigation shows that the normal human vocal fold emits overtones that are very nearly precise integral values of the fundamental. Physiological problems of the vocal folds, however, introduce mechanical nonlinearities that manifest themselves as frequency deviations from the ideal harmonic (that is, integral) values. The authors quantify this inharmonicity, describing and illustrating how one can efficiently obtain and analyze such data. They outline, as well, a proposed investigation to assess the clinical sensitivity and significance of the analysis discussed in this work in conjunction with laryngoscopic diagnosis of pathology.
Fabric dependence of poroelastic wave propagation.
Authors: Cowin Stephen , Cardoso Luis
Published: October 2013

The governing equations for wave motion in the linear theory of anisotropic poroelastic materials are developed and extended to include the dependence of the constitutive relations upon fabric. Fabric is a quantitative stereological measure of the degree of structural anisotropy in the pore architecture of a porous medium. With the addition of the second order symmetric tensor fabric variable, the formulation of wave motions in the poroelastic theory is consistent with the presentations of Biot and later authors. The dependence of all the material tensors in the Biot theory on the fabric tensor aligns the material tensors, so when a single direction that is a plane of material symmetry is selected, the equations simplify considerably. The customary polynomial of the sixth deg for the wave speeds of the anisotropic Biot theory in a selected direction reduces to three quadratic equations to solve for the wave speeds and attenuation. While the theory is applicable to any saturated porous material, the two longitudinal waves predicted by this model are measured in cancellous bone and used to derive the corresponding anisotropic elastic constants. Representative examples of bone loss are analyzed as a function of the porosity, tissue density, and fabric.
Dynamic and acoustic modeling of discrete biologics for active sonar simulation.
Authors: La Cour Brian R. , Hamann John E.
Published: October 2013

A model is proposed for simulating the group dynamics and acoustic echoes of aggregate, discrete biologics in midfrequency (2–5 kHz) active undersea sonar. Using a Lagrangian description, group behavior is modeled by a set of Newtonian forces and stochastic perturbations on a collection of point masses. Interactions comprise a grouping force, which gives a characteristic separation distance, and an arrayal force, which tends to align the velocities of the group’s constituents. The group dynamics is characterized in terms of their statistical and asymptotic properties and studied as a function of the model parameters. Several models for the acoustic response are considered and studied for both individual and aggregate response. Finally, the resulting synthetic echoes are compared against those of actual biologics measured on a midfrequency active sonar system. The synthetic echoes are found to reproduce well both the qualitative characteristics of measured biologics and the resulting tracking and classification features found in a typical active sonar signal and information processing chain.
Exploring spatiotemporal distribution as a clutter simulation validation measure.
Authors: Arvelo Juan I.
Published: October 2013

The amplitude distribution is widely used to compare modeled and measured undersea clutter [J. Arvelo et al., JASA 120, 3381 (2006)]. However, additional validation measures must be identified to ensure that clutter models are suited to realistically simulate active sonar displays and accurately emulate tracker performance. For example, the amplitude distribution ignores the stochastic arrangement of clutter at various space/time scales [V. Lupien, JASA 105, 2187–2282 (1999)]. Active midfrequency vertical line array data from the ASIAEX 2001 experiment in the East China Sea is processed to explore the suitability of the clutter spatiotemporal distribution as a key validation measure. The vertical array permitted the separation of bottom from surface generated clutter. A physics-based seafloor clutter model [B. Newhall and J. Arvelo, JASA 118, 2041 (2005)] was implemented to simulate the experimental scenario with known measured and inferred environmental conditions. Comparisons of the measured and simulated amplitude and spatiotemporal distributions uncovered significant effects that must be included to improve existing clutter models. [This effort was conducted under the auspices of the Undersea Warfare Business Area Independent Research and Development program of the Johns Hopkins University Applied Physics Laboratory.]
Absorption coefficients part 2: Is “edge effect” more important than expected?
Authors: Sauro Ron , Vargas Michael , Mange Gary
Published: October 2013

Attempting to correlate the measurements of absorption coefficients in ASTM-C423, ISO-354, and ISO-17497-1, it was observed that the results were varying to a large degree. An experiment was set up as described in a paper titled “Absorption coefficients part I: Is square area enough?” It was observed that the edges of the sample had a significant effect on the absorption coefficient. The results of these experiments are presented in numerical and graphic form in this paper along with conclusions and suggested corrections to the “absorption coefficient” as used in all calculations in acoustics.
Killer whale habitat use and prey fields from remote hydrophones and echosounders.
Authors: Veirs Scott , Veirs Val , Wood Jason , Moore Brian , McClure Bob , Otis Bob
Published: October 2013

The Salish Sea Hydrophone Network has been providing live audio streams to listeners around the globe for the past three years. Five hydrophones around the core summer habitat of the endangered southern resident killer whales allow detection of killer whale presence and inference of pod identity based on call associations. Detection of calls, whistles, and clicks is accomplished automatically by spectral and time domain analysis and manually by a global network of trained human listeners. The hydrophone network is more effective than a sighting network for detecting killer whales during inclement weather and at night, and for generating real-time notifications to alert researchers and managers. Additionally, the live streams and archived recordings have enriched educational activities of local museums and aquariums. In 2008, the hydrophone at Lime Kiln State Park was supplemented by hydroacoustic surveys conducted using a Biosonics echosounder (200 kHz). From August through December the echosounder was deployed at 15 m depth to conduct a continuous, fixed, horizontal survey. Remote display technology was used to monitor the echosounder in real time while also listening to the live audio stream. The resultant time series of fish density and acoustic behavior of killer whales is presented.
Cavitation bubble activity during treatment of cortical bones by shock waves.
Authors: Bossis Dorothée , Padilla Frederic , Cleveland Robin O.
Published: October 2013

Shock wave (SW) induced cavitation might be a physical effect by which bioeffects on bones are mediated, especially for SW treatment of bone nonunion. To assess the presence of cavitation and to study bubbles activity at the surface of cortical bones, we treated rat femurs with SWs using a clinical SW therapy device (Ossatron). Sequences of 14 images were acquired using a high speed camera capable of recording up to 100 million frames per second (Imacon). The sequences showed that for all voltage settings of the Ossatron a cloud of cavitation bubbles was induced at the surface of the bone. The bubbles near the surface of the bone appeared to form and act as a single larger bubble, which collapsed violently against the surface of the bone. For a voltage setting of 28 kV the collapse time was measured to be 720 micro-seconds after a single SW and reduced to 620 micro-seconds after 10 SWs at 1 Hz. In the case of a bone with an artificially fractured surface cavitation events were found to occur preferentially within the fracture gap. Cavitation might therefore be an important mechanisms in the SW treatment of bone defects.
Hot topics in youth education outreach.
Authors: Klonoski Grace
Published: October 2013

This presentation will focus on ways in which professional societies and their volunteers can make a lasting, positive difference in supporting the science and math learning of young students. The introduction will provide a brief overview of trends in student achievement in math and science and will discuss the availability of qualified teachers in the United States. Four features of effective learning environments will be described. The remainder of the presentation will be devoted to examples of how scientific communities can become directly involved in reaching out to students on a local and global scale. A variety of youth programs hosted by the Optical Society of America (OSA) and the OSA Foundation will be highlighted with an emphasis on the scope, goals, and quantitative results of each initiative. From a multilingual Web site that provides students, teachers, and parents with basic science information, lesson plans, and hands-on activities, to the production and worldwide distribution of “optics suitcases” that give students the opportunity to participate in hands-on demonstrations, OSA's recent efforts have benefited thousands of individuals in more than 20 countries. The planned collaboration between ASA and OSA to develop acoustics-focused classroom materials, a Web site, and demonstration kit will be described.
Temperature dependence of elastic moduli for polycrystalline Pu: Comparison of alpha and gamma phases.
Authors: Stroe I.R. , Betts J. B. , Pantea C. , Trugman A. , Mitchell J. N. , Ramos M. , Freibert F. , Mielke C.H. , Migliori A.
Published: October 2013

The elastic properties of pure polycrystalline Pu were investigated as a function of temperature by resonant ultrasound spectroscopy. For both alpha and gamma phase, shear (G) and longitudinal (CL) elastic moduli were determined simultaneously and the bulk modulus (B) was computed from them. In alpha phase, G and B exhibit the same temperature dependence, but an unusually large change. This behavior together with a high Gruneiser parameter and an almost temperature independent Poisson ratio is attributed to the 5-f electron localization delocalization. In the gamma phase, G and B show anomalous temperature behavior: G decreases with temperature while B is near temperature independent. The Poisson ratio increases with temperature by 4%. This normal behavior of the Poisson ratio is unusual for Pu.
Resonant ultrasound spectroscopy studies of Fe-based superconductors.
Authors: Keppens Veerle , VanBebber Lindsey , Luan Yanbing , McGuire Michael A. , Sefat Athena , Sales Brian C. , Mandrus David
Published: October 2013

The discovery of high superconducting transition temperatures in Fe-based compounds has generated a frenzy of experimental and theoretical research activities on these systems. Whereas doping is required to establish superconductivity, careful studies of the undoped materials are important to elucidate the underlying physics. Recently, resonant ultrasound spectroscopy measurements were carried out on the undoped oxypnictide system LaFeAsO as well as the oxygen-free systems BaFe2As2 and Ba(Fe, Co)2As2. The elastic response of the parent compounds shows a very gradual softening corresponding to the structural transition that characterizes these systems. Remarkably, this softening persists in the superconducting samples, even though the structural transition in these compounds is suppressed.
Using auditory feedback during vocalization: Different mechanisms for utterance onset and pitch maintenance.
Authors: Hawco Colin S. , Jones Jeffery A.
Published: October 2013

During vocalization, auditory feedback is used to attain and maintain a desired fundamental frequency (F0). The use of auditory feedback to control vocalization has been studied using adaptation studies, in which an F0 feedback alteration is maintained across many trials, and using midutterance perturbations, where a brief F0 change is introduced during an ongoing utterance. Participants vocalized during two blocks. In an adaptation block, a one semitone F0 shift was maintained for 40 trials, and midutterance perturbations were introduced by removing the feedback alteration. In a control block, a midutterance perturbation was introduced in trials, which were either unshifted or shifted randomly by one semitone at before the onset of vocalization (similar to the adaptation trials). F0 compensation to midutterance perturbations was identical in all conditions, and was always smaller than the compensation to a shift at utterance onset. These results are explained by a change in the control strategy at utterance onset and mid-utterance. At utterance onset, auditory feedback is compared to feedback predicted by a forward model to ensure the pitch goal is achieved. However, after utterance onset, the control strategy switches and stabilization is maintained by comparing feedback to previous F0 production.
Function words of lexical bundles: The relation of frequency and reduction.
Authors: Lemke Shannon F. , Tremblay Antoine , Tucker Benjamin V.
Published: October 2013

Studies of spontaneous speech have shown frequency effects on the amount of reduction produced by speakers, demonstrating that predictability facilitates production of a target word [Shi et al. (2005); Jurafsky et al. (2001); Bell et al. (2003)]. This paper investigates the amount of reduction produced in laboratory recorded speech and considers the effect of frequency on the duration of function words in four-word sequences. It is also found that the influence of frequency has an effect on holistically storing these bundles. An interaction between word position and the third-order transitional probability (ABC → D) has been established, indicating that greater third-order transitional probabilities predict shorter function word durations in the first and second positions of a bundle, and, therefore, involve more durational reduction. The current research shows that, just as frequency affects reduction in spontaneous speech, there is an effect in laboratory produced speech as well. These findings indicate that multiword sequences are stored as lexical units.
Basic word segmentation abilities emerge earlier in infancy than previously thought.
Authors: Johnson Elizabeth K. , Seidl Amanda
Published: October 2013

English-learning 7.5- but not 6-month-olds extract word forms from fluent speech (Jusczyk et al., 1999). Thus, English learners are thought to begin segmenting words from speech by 7.5 months. However, recent research has shown that when target words are flanked by a frequent and emotionally salient word (e.g., the infant’s name), even 6-month-olds can extract words from speech (e.g., Bortfeld et al., 2005). This suggests that basic word segmentation capabilities may emerge earlier than past studies have suggested. Using the Headturn Preference Procedure, we tested 6-month-olds’ ability to segment utterance-flanked words from speech, e.g., “geff” from “At the circus we met a silly geff.” Infants were familiarized with passages containing target words in utterance initial and final position, and then tested on their recognition of these words in isolation. A significant looking time difference to familiar versus unfamiliar words was found, indicating that 6-month-olds segmented the target words from speech. Six-month-olds’ success at segmenting utterance-flanked words from speech is particularly interesting because infant-directed speech consists of short utterances containing many utterance-flanked words. Segmentation of utterance-flanked words could help infants learn the cues needed to extract harder utterance-medial words from speech (see Seidl and Johnson, 2006).
Planning time effects of phonological competition: Articulatory and acoustic data.
Authors: Mooshammer Christine R. , Goldstein Louis , Tiede Mark , Kulshreshtha Manisha , McClure Scott , Katsika Argyro
Published: October 2013

One major cause for speech production variability and errors is competition between phonologically similar sequences in an utterance. Since one recent model of speech production planning [Nam (2004)] also posits a systematic relation between planning time and kinematic variability, we decided to directly investigate whether competition increases planning time, i.e., whether it takes longer to initiate a sequence such as “tape cape” compared with “tape tape.” Effects of competition in the onset were compared to competition in the coda (e.g., “tape take”). Results from two studies are reported: articulatory latencies from a delayed naming task recorded using EMA (four speakers), and acoustic latencies from a delayed naming task, a simple naming task, and a picture naming task (ten speakers). Latencies were significantly affected by competition, i.e., latencies were longer for items like “tape cape” and “tape take” than for “tape tape.” However, no significant differences were found in competition effects between onset and coda positions. Apart from latency, overall duration increased and clusters formed across words showed less overlap. Observed effects on latency were largest for picture naming, followed by simple naming and least for delayed naming. [Work supported by NIH DC008780.]
Perception of voiced-only and noise-vocoded speech by a language-trained chimpanzee (Pan troglodytes).
Authors: Heimbauer Lisa A. , Beran Michael J. , Owren Michael J.
Published: October 2013

The ability of human listeners to understand speech even in altered or synthetic forms is argued to be evidence of uniquely human processing abilities. However, extensive early experience with speech may also contribute to this capability. To investigate this issue two experiments were designed to test the ability of Panzee, a 22-year-old language-trained chimpanzee, to recognize words in synthetic form. Like a human child, she was reared from infancy by human caregivers who routinely spoke to her. She communicates with humans by identifying words using graphical symbols (lexigrams). Experimental training and testing were conducted with two different sets of 24 familiar words presented one-per-trial in natural, voiced-only, or noise-vocoded forms, with Panzee choosing one of four lexigrams presented on a computer monitor. Experiment 1 showed equivalent performance with words heard in natural form versus voiced-only versions, resynthesized from only voiced components of a word. Noise-vocoded words presented in Experiment 2 simulated effects of hearing using a cochlear implant and were based on amplitude-modulated noise bands. Performance with these sounds was significantly higher than chance, but also lower than with natural words. Results suggest specialized processing mechanisms are not necessary to speech perception in the absence of traditional acoustic cues.
Listening to natural versus cell phone speech on multiple simultaneous tasks.
Authors: Nirmal Kumar Srinivasan , Thomas Carrell
Published: October 2013

In typical listening environments, attention is often divided and may have different effects on automatic and controlled processes. Automatic processing is a fast, parallel process not limited by short-term memory, requires little subject effort, but requires extensive consistent training to develop. Controlled processing is a comparatively slow, serial process limited by short-term memory, requires subject effort, and little training to develop [Schneider and Shiffrin (1977)]. In the present study a methodology was developed to examine effects of controlled and automatic distracters on the perception of distorted speech. Specifically, perception of natural and cell phone speech was investigated while listeners performed simultaneous visual and motor tasks. Young, normal-hearing native speakers of English were presented with SPIN sentences [Kalikow et al. (1977)] in a background of multitalker babble [Bilger et al. (1984)] using natural and cell phone speech. Prior to the start of the experiment, participants had been trained on visual task using either consistent mapping technique or varied mapping technique. Word recognition scores, pursuit rotor performance, and visual task performance were compared for natural and cell phone speech. The relationship between consistently mapped and variably mapped distracters on perceptual and behavioral performance provides information necessary for more detailed models relevant to real-world environments.
Effects of audio-visual speech information on recognition memory of spoken words.
Authors: Sanchez Kauyumari , Miller Rachel M. , Rosenblum Lawrence D.
Published: October 2013

Audio-visual speech has generally been found to contain more usable information than audio-only speech. However, there is conflicting evidence of whether seeing the face of a speaker facilitates memory for spoken words [e.g., Sheffert et al., Cog. Tech. 8, 42–50 (2003)]. To address this issue, three experiments examined whether an audio-visual benefit would be observed on a word recognition task. Experiment 1 compared recognition of spoken words both presented and tested in audio-visual versus audio-only forms. Audio-visual word stimuli were recognized significantly better than audio-only words. Experiment 2 tested whether this benefit was due to the presence of visible articulatory information or simply more information in general. Recognition of words presented (and tested) in audio-only, audio-visual, and audio with accompanying static face image conditions were compared. Words presented in audio-visual (dynamic face) form were recognized better than audio-only and audio-static face stimuli. To test whether the benefit of audio-visual presentation was due to encoding, retrieval, or both, Experiment 3 crossed presentation modality (audio-only versus audio-visual) from presentation to test phases. Results showed that the audio-visual form is required in both encoding and retrieval to be beneficial.
Estimating higher moments of shallow water reverbation for non-Gaussian scatterer distributions.
Authors: LePage Kevin D.
Published: October 2013

Reverberation is described as a random process by which deterministic propagation components weight and sum scattering amplitudes over the sonar footprint. A method of estimating the second, third, and fourth monents of the scattered field pressure is described for scatterers which have a Chi Squared model for the amplitude pdf. Comparison of theoretical estimates of the fourth moment to Monte Carlo estimates of the same quantity obtained using a NRL 2-way parabolic equation PERM show good agreement. [Work supported by ONR.]
Acoustical design of mixed-use buildings: The state of the art (and science).
Authors: Alvarado Robert P. , Salter Ethan C.
Published: October 2013

Mixed-use developments integrate a variety of uses including residences, offices, shops, restaurants, and theaters into functional, living, and working communities. They are often located near rail, major roadways, and airports, which can generate significant levels of environmental noise and vibration that will need to be mitigated to meet Building Codes and project goals. This paper will detail project-specific issues, solutions, and experiences by Charles M. Salter Associates. Our experience has given us the opportunity to collaborate with various project stakeholders to achieve project goals within the constraints of aesthetics, budget, and space. Authors will present case studies which include acoustical design issues that have been incorporated during the design phase, coordinated during construction, and conveyed to the community that the project serves. Acoustical needs of mixed-use developments can vary based on applicable Codes, as well as project marketing goals and expectations of end users. Educating future owners and tenants about acoustics is important to reducing the design team and the developers’ exposure to possible litigation, and also helps to maintain resident health, comfort, and property values. Robert Alvarado has managed hundreds of projects over the past 12 years. His mixed-use project portfolio includes international and domestic projects. Ethan Salter has consulted on dozens of projects throughout the country, including several incorporating sustainable design.
Vibration characteristics of the tympanoperiotic complex in the bottlenose dolphin, Tursiops truncatus.
Authors: Krysl Petr , Cranford Ted W. , Hildebrand John A.
Published: October 2013

Modal finite + boundary element analysis of a bottlenose dolphin’s bony tympanoperiotic complex, including the ossicles, was performed to determine the mode shapes and natural frequencies. The goal was to gain insight into the transmission of sound pressure waves arriving through the soft tissues and transmitted across the bony components into the oval window of the inner ear. The finite element model of the bones was derived from CT scans with a 360 μm voxel resolution. In the first approximation the soft tissue was considered to be acoustically equivalent to an incompressible inviscid liquid, taken as infinite in extent. The added mass terms were computed with a boundary element model. The computed frequencies cover the range up to 160 kHz. The capacity of the natural vibration modes to excite motion of the stapes footplate was assessed by measuring the relative motion of the incudostapedial joint normalized by the normal displacement of the wet-surface of the ear bones. In addition to a quantitative assessment a number of qualitative observations may be made that could explain the function of the dolphin’s ear complex. For example, the vibrational patterns are nontrivial and frequency dependent. [Work supported by the U.S. Navy CNO45.]
“Rivers” of sound in Cuvier’s beaked whale (Ziphius cavirostris): Implications for the evolution of sound reception in odontocetes.
Authors: Cranford Ted W. , Krysl Petr , Hildebrand John A.
Published: October 2013

Industrial CT scanning technology was used to collect the first x-ray tomograms from the head of an adult male Cuvier’s beaked whale. These scans and tissue property measurements were used to construct a finite element model. Simulations revealed pathways for sound propagation into and out of the head. One intriguing result concerns a newly described gular pathway by which sound reaches the hearing apparatus. Propagated sound waves enter the ventral aspect of the head and form an acoustic “river” that flows toward the bony ear complexes through the internal mandibular fat bodies. The precise pathway and dimensions of the sound river vary with frequency, but it converges on the bony tympanoperiotic complex. A combination of tissue structures and air spaces act like an internal acoustic pinna that filters and concentrates the incoming sound. The river of sound apparently functions in concert with the absence of the medial bony lamina of the posterior portion of the mandible, a condition that exists in all toothed whales and their ancestral archaeocetes. The gular pathway and river of sound suggests that this is the primordial pathway for underwater hearing in whales and that Norris’ jaw hearing mechanism was a more recent development.
Dall’s porpoise (Phocoenoides dalli) echolocation click spectral structure.
Authors: Bassett Hannah R. , Baumann Simone , Campbell Gregory S. , Wiggins Sean M. , Hildebrand John A.
Published: October 2013

Dall’s porpoise (Phocoenoides dalli) echolocation clicks have not been widely recorded. Concurrent with visual observations, acoustic recordings of free-ranging Dall’s porpoise were made offshore of southern California using a towed hydrophone array with two elements of 250 kHz bandwidth. We examined 6035 clicks from 12 sessions totaling more than two hours over the course of seven days. The Dall’s porpoise echolocations recorded were short (48–804 μs), narrow band (2–10 kHz [−3dB]) clicks with most peak frequencies between 117 and 141 kHz, but some as high as 198 kHz. Many clicks contained a multipulse temporal structure, resulting in stereotyped spectral peaks and notches. Two distinctive click types with different spectral banding patterns and peak frequencies (122.8 and 135.8 kHz) were observed. Spectral banding patterns have been used as a species identifier for Risso’s dolphins and Pacific white-sided dolphins. These two dolphins and Dall’s porpoise have similar head morphologies, which may play a role in producing clicks with spectral peaks and notches. This study shows that Dall’s porpoise produce multiple click types, which may provide a tool for population classification, and that their clicks contain spectral banding patterns, which may provide insight into the mechanism by which such clicks are produced.
The acoustic implications of sella length in horseshoe bats.
Authors: Mülller Rolf , Zhang Zhiwei , Nguyen Truong Son
Published: October 2013

Horseshoe bats emit their biosonar pulses through nostrils that are surrounded by elaborate baffle shapes (noseleaves). The shape and size of the different noseleaf shape elements can vary considerably between species. Here, the acoustic effects of the length of the sella have been investigated based on the noseleaf of Bourret’s Horseshoe Bat (Rhinolophus paradoxolophus) which features an exceptionally long sella: High-resolution digital representations of the noseleaves of three specimens were used to vary the sella length below and above its natural value. A principal axis through the sella was used to define the direction of this scaling. The acoustic beamforming properties of the noseleaf were then assessed as a function of sella scale using numerical methods. It was found that elongating the sella narrows the biosonar beam of the second harmonic in elevation. Furthermore, the natural length of the sella in Bourret’s Horseshoe Bat coincided with a fiducial point in the relationship between sella length and beamwidth, where the effect of sella length on beamwidth saturates. This allows the prediction of the natural sella length from its acoustic properties. The long sella in this species could, hence, be an adaptation to producing a narrow beam at comparatively low frequencies.
Combined effect of ultrasound and liposomal doxorubicin on AT2 Dunning tumor growth in rats: Preliminary results.
Authors: Somaglino Lucie , Bouchoux Guillaume , Chesnais Sabrina , Amdouni Anis , Mestas Jean-Louis , Fossheim Sigrid , Nilssen Esben A. , Chapelon Jean-Yves , Lafon Cyril
Published: October 2013

Previous in vitro studies conducted in our group have shown the feasibility of monitoring drug release from liposomes by an inertial acoustic cavitation index. We currently report in vivo experiments utilizing the cavitation index in combined treatment of AT2 Dunning tumor grafted rats with focused ultrasound and liposomal doxorubicin. Sixty-three rats were allocated into seven groups: control, low level ultrasound treatment, high level ultrasound treatment, free doxorubicin+high level ultrasound treatment, and liposomal doxorubicin, liposomal doxorubicin+low level ultrasound treatment, and liposomal doxorubicin+high level ultrasound treatment. Based on pharmacokinetic studies, it was decided to apply ultrasound to the tumor 48 h after drug injection. An experimental setup was built to perform repeatable and rapid sonications of tumors monitored by the cavitation index. Tumor growth was assessed for a period of 35 days after tumor inoculation. Results showed that liposomal doxorubicin significantly slowed down tumor growth. However, the synergy between ultrasound and liposomal doxorubicin could not be firmly demonstrated. The lack of synergy may be due to inefficient induction of drug delivery in vivo or too high liposome dosage hiding synergistic effects. [Work funded by the Norwegian Research Council (NANOMAT programme). Epitarget AS is acknowledged for the supply of liposomes.]
Ultrasound-enhanced drug delivery through sclera.
Authors: Shah Robin , Zderic Vesna
Published: October 2013

Achieving an increase in drug delivery through the sclera is important in the treatment of the back of the eye diseases including macular degeneration, diabetic retinopathy, etc. Our objective is to utilize therapeutic ultrasound in enhancing drug delivery through the sclera. Porcine sclera was placed in a standard diffusion cell at a normal physiological temperature of 34 °C. Solution of sodium fluorescein, a hydrophilic drug-mimicking compound, was added to donor compartment, and receiver compartment was filled with saline. The sclera was exposed to ultrasound for 5 min (intensities 1.2–1.8 W/cm2 and frequencies 0.5 to 5 MHz). After 60 min, solution samples were taken from the receiver compartment to determine the concentration of sodium fluorescein. The sclera permeability to the drug mimicking agent in vitro increased 3.5 times at 0.5 MHz (p-value of less than 0.05), 1.7 times at 1 MHz, 3.5 times at 3.5 MHz (p-value of less than 0.05), and 1.5 times at 5 MHz. The average temperature of the sclera during ultrasound exposure was 42 °C. No gross changes were observed in the sclera due to ultrasound application. Future work will focus on determination of optimal ultrasound parameters for the drug delivery through the sclera.
Influence of finite wall impedance on contrast agent bubble behavior near a membrane.
Authors: Hay Todd , Overvelde Marlies , Dollet Benjamin , Garbin Valeria , de Jong Nico , Lohse Detlef , Versluis Michel
Published: October 2013

Experiments investigating the radial dynamics of ultrasound contrast agent (UCA) microbubbles in the vicinity of an optically transparent membrane show that bubble oscillation amplitude and frequency of peak response decrease as bubbles move closer to the membrane (Overvelde et al. Proc. 19th Intl. Congr. Acoust., 2007). However, treating the membrane as a rigid wall predicts that the peak oscillation amplitude should increase at small standoff distances, contrary to experimental observations. Here we present a model describing UCA bubble dynamics near a locally reacting wall having finite acoustic impedance. If finite wall impedance is included in the model, the predicted bubble behavior is in good agreement with observations. The hybrid time-frequency domain model is based on a linear frequency domain solution [Ingard, J. Acoust. Soc. Am. 23, 329 (1951)] which has been adapted to account for weakly nonlinear bubble oscillations and UCA shell dynamics. Wall impedance parameters are derived from independent experimental measurements. Comparisons between the model and data from microbubble spectroscopy experiments will be presented. [Work supported by the ASA Hunt Fellowship and NIH DK070618.]
Subharmonic response from single, polymer-shell contrast agents subjected to high-frequency excitation.
Authors: Chitnis Parag V. , Mamou Jonathan , Lee Paul , Ketterling Jeffrey A.
Published: October 2013

Three polymer-shelled agents (nominal mean diameters of 0.56, 1.1, and 3.4 μm) from POINT Biomedical were investigated to determine the optimal parameter space for generating a subharmonic response from single agents when subjected to high-frequency (above 20 MHz) excitation. A flow phantom was constructed to restrict the flow of a dilute contrast agent solution to a small volume. Two single-element transducers, with nominal center frequencies of 40 and 20 MHz, were aligned such that they were confocal and orthogonal to each other, and their mutual focus was positioned within the flow phantom. The 40 MHz transducer was used in transmit/receive mode while the 20 MHz transducer was used passively in the receive mode. The radio-frequency backscatter signals from individual contrast agents were digitized simultaneously from both transducers under a variety of pulse durations (5–20 cycles), acoustic pressure levels (1.5–6.0 MPa), and driving frequencies (35–45 MHz). Echo signals from individual contrast agents were windowed and spectra were calculated. For each contrast agent, the magnitude of the subharmonic (20–MHz) response was normalized with respect to the magnitude of the fundamental (40–MHz) backscatter. Experimental results agreed closely with theoretical calculations. [Work supported by NIH EB006372.]
Preparing a submission to the Journal of the Acoustical Society of America on applied projects in architectural acoustics.
Authors: Wang Lily M.
Published: October 2013

The Journal of the Acoustical Society of America (JASA) encourages authors to submit articles for publication that are based on more applied projects, such as those commonly found in the technical area of architectural acoustics. However, very few of this type have been published in the recent past. Suggestions on how such articles should be prepared and how they may meet the “significance” criterion will be given, from the viewpoint of a current JASA associate editor in architectural acoustics. Additionally a review of such articles that have been published in JASA within the past few decades will be provided.
Manuscript preparation—How Acta Acustica united with Acustica compares with the Journal of the Acoustical Society of America.
Authors: Botteldooren Dick , Vorlaender Michael
Published: October 2013

Scientific writing is essential for academic progress and technical innovation. Rules and ethics for writing are well-defined, and detailed guidelines for authors are available. Nevertheless, journals have a specific flavor which is not only related to the focus of content. Thus, for authors preparing a manuscript, the choice of journal is an important issue. Based on survey material and analyses of past publications, differences between Acta Acustica united with Acustica (AA.A) and JASA will be highlighted. Journal policy has to deal with the variety of manuscript content covering the span from fundamental science to technical applied papers. The readers expect both, and this is even more important for society journals like JASA and AA.A. Review processes that guarantee equal quality of technical and purely academic contributions, yet keep in mind their own specificity, are accordingly difficult to set up. Recent changes in handling the review of technical and applied papers in AA.A will be discussed.
The effect of musical experience on describing sounds with everyday words.
Authors: Sarkar Mihir , Lan Cyril , Diaz Joseph , Vercoe Barry
Published: October 2013

Musicians often use non-technical words such as “warm,” “sharp,” or “sweet” to describe sound quality. Commonplace experience indicates that the descriptions of a sound by a diverse group of musicians may vary, suggesting that musical background may influence one’s interpretation of a sound. A research study was carried out targeting 844 subjects of varying musical backgrounds where each subject had the chance to match various words to sound samples. Each subject was assigned to one or more musical categories (strings, woodwinds, electronic, percussion, brass) based on previous musical experience, and the results were compared across categories. Statistical measures were employed to determine if a correlation existed between musical background and survey responses. After analyzing the results from all sound-word combinations, it was determined that the musical background had no effect on the selection of words. Because of the nature of statistical hypothesis testing, the expected rate of false positives was greater than the proportion of statistically significant sound-word combinations. From the data collected in this user study, it is reasonable to suggest that the description of musical sounds is an innate skill that is not influenced by musical background and training.
The new comprehensive acoustical criteria for healthcare facilities.
Authors: Sykes David M. , Tocci Gregory
Published: October 2013

New comprehensive acoustical guidelines for healthcare facilities were drafted for the American Institute of Architects and the American Hospital Association in 2005–6 by the 500-member TC-AA.NS.SC (Speech Privacy & Healthcare Acoustics) which is chaired by Gregory Tocci, David Sykes, and William Cavanaugh. Following two rounds of public review, these guidelines were approved for use by the Green Guide for Healthcare in 2007 and in early 2009 they were issued as the sole “Reference Standard” for two new LEED “Indoor Environmental Quality” credits. In early 2010, following two additional rounds of public review, the same guidelines will be released by the Facility Guidelines Institute and the American Society of Healthcare Architects (a division of the American Hospital Association) in the authoritative, code-level document, “FGI/ASHE Guidelines for the Design and Construction of Hospitals and Healthcare Facilities.” Practitioners and researchers need to be aware of these criteria when designing acoustical solutions for healthcare facilities. This paper will present an overview of the guidelines. The speaker is co-chairman of the technical committee responsible for drafting the criteria and of ANSI S12 WG44, which is currently developing an additional new healthcare acoustics standard.
Mechanical equipment and ambulances. Strange bedfellows of cardiovascular services.
Authors: Himmel Chad N. , Evans Jack B.
Published: October 2013

A case study will be presented regarding vibration and noise control design for an existing heart hospital. Facility expansion within a crowded site necessitates sandwiching a suite of new cardiac catheterization laboratories between mechanical equipment rooms above and the hospital’s main ambulance driveway below. The facility expansion also includes cardiac computed tomography, magnetic resonance imaging, and nuclear imaging, plus cardiovascular care, treatment, and administrative support spaces. Procedure and support spaces can be disturbed by mechanical equipment noise and vibration and noise from ambulance siren. Cardiac procedure instruments and imaging can be disturbed by low frequency noise and vibration from building mechanical systems, ambulance traffic, and building occupants. Design criteria for permissible building vibration and continuous background noise will be presented along with relevant sources and bases. Measurement evaluation results for design will be contrasted with criteria. Measures incorporated in design to mitigate vibration and noise on catheterization laboratories will be discussed. Measures considered in design include structural floor “detuning” concepts, stiffened supports for catheterization laboratory C-arms, mechanical equipment vibration isolation mounts, and floating concrete floor systems for mechanical rooms. If available, postconstruction spectral analysis measurements of building noise and vibration will be presented.
Early years of the parametric array—An anecdotal history.
Authors: Blackstock David T.
Published: October 2013

This review covers the period from 1960 to about the mid-1970s. Westervelt presented his theory of the parametric array at the June 1960 Acoustical Society Meeting, held at Brown Univ. In the same session, Bellin and Beyer reported experimental confirmation, primarily for the array in water. Despite the tantalizing properties of the parametric array—narrow low-frequency beam produced with a small source, absence of sidelobes, and potentially broadband operation—the acoustical community at first paid little attention. Berktay woke us up with a series of papers in the mid-to-late 1960s on possible applications. Interest in underwater parametric arrays then exploded, including attempts to make parametric receiving arrays practical. Definitive experimental confirmation of the parametric array in air was finally reported in 1973. However, practical applications of the airborne array did not appear until many years later.
Parametric acoustic array development at the U.S. Navy’s New London, Connecticut laboratory.
Authors: Browning David G. , Moffett Mark B. , Konrad William L.
Published: October 2013

A brief history of the development of parametric acoustic sources at the U.S. Navy Underwater Sound Laboratory (USNUSL), and its successor, the Naval Underwater Systems Center is presented. Inspired by Robert Mellen, the Parametric Sonar Group was formed to explore the practical implications of Westervelt’s idea for underwater acoustics. Spanning more than two decades, this research pursued various potential applications exploiting the unique characteristics of parametric sources, including echo-ranging in reverberant environments, communications involving voice, data, music, and video signals, target-strength measurements, bottom bathymetry, high-resolution sub-bottom profiling, and measurements of scattering and reflection from surfaces. Parametric source design procedures were developed, and guidelines were established for diagnosing and avoiding undesirable effects, such as difference-frequency instability and spurious nonlinearities, such as direct radiation from the projector, cavitation, and receiver nonlinearity. Theoretical models extended the Westervelt theory to realistic primary fields. For planar projector arrays, parametric source design curves, valid for levels in the primary far field, enabled designers to predict performance without resorting to computer calculations. To obtain source-levels and beam-widths within the primary near field, where the secondary signal is generated, a computer program, called CONVOL5 in its present configuration, can be used to obtain more detailed performance predictions.