bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulations of broadband acoustic propagation through a sound-speed field impacted by oil.
Authors: Vera Michael , Stephens James M.
Published: October 2010

Because its sound-speed characteristics differ substantially from seawater, the presence of oil in the water column might be expected to impact acoustic propagation in the ocean environment. Empirical expressions are employed for the sound speed in oil; it depends on the API (a measure of density), temperature, and pressure. Environmental data taken in the vicinity of the Deepwater Horizon site taken during the 2007 Littoral Acoustic Demonstration Center experiment are used to generate profiles of temperature, pressure, and sound speed. Different values of API and different distributions for the weighting fraction of the oil on the total sound speed are employed in numerical simulations. The computed, received acoustic fields for different values and locations of oil concentration are compared to the case where no oil is present in several source-receiver ranges. These forward models are intended to examine the feasibility of acoustically tracking oil as it travels from a source upward through the water column, or in locating oil suspended in the water column. These computations can aid in identifying the limitations on a realistic experimental scenario.
Application of an acoustic inversion technique to infer the presence of oil from anomalies in the water column sound speed profile.
Authors: Ballard Megan S. , Wilson Preston S.
Published: October 2010

This work attempts to exploit the difference in sound speed between oil and seawater to determine the location of large underwater oil plumes. Two perturbative inversion schemes, both based on the work of Rajan, et al. [JASA 82, 998–1017 (1987)] will be presented. Both methods can be used to estimate sound-speed in the water column as a function of range and depth. The first technique uses horizontal wavenumber data which are estimated from the complex pressure field of a narrow band signal. The inversion result provides an estimate of sound speed profile along a two-dimensional slice through the environment. The method is demonstrated using data from the Shallow Water 2006 (SW06) experiment. The second technique utilizes modal travel time data. When applied in a multi-sensor deployment, the outputs of this inversion scheme provide a three-dimensional characterization of the coastal environment. Furthermore, because sound propagates at a much faster speed than oil spill spreads, this technique can be used to track changes in the size and shape of the oil plume over time. [Work supported by ARL:UT IR&D]
A doubly resonant source and associated signals in the 2009/2010-2011 Philippine Sea experiments.
Authors: Andrew Rex K. , Mercer James A.
Published: October 2010

An experimental transducer invented by Jack Butler of ImageAcoustics, Inc., and built by Massa Products, Inc., was loaned in 2005 to APL/UW by Jan Lindberg. APL/UW developed a ship-suspended system by integrating the transducer with a tuner built by Coiltron, Inc., a tracking pinger, an associated telemetry subsystem, and a pressure-balanced oil-filled battery. The transducer itself is a double-ported free-flooded device with sharp resonances at 210 and 320 Hz. The “band” spanning these resonances supports wideband signals, and for the PhilSea09 exercise a Q=2 m-sequence was used. The double-peaked response required considerable pre-equalization for controlled time resolution. For 2010, an experimental two-frequency “broadband bichromatic” signal was devised by superposing two high-Q m-sequences with carriers near the two resonance frequencies. To date, the system has logged about 100 h of high-resolution pulse interrogations of the deep Philippine Sea at ranges of 45, 107, and 500 km. Examples and results will be discussed. [Work sponsored by ONR code 322OA.]
Deep-water propagation measurements from a towed-array.
Authors: Heaney Kevin D. , Campbell Richard L. , Baggeroer Arthur B. , D’Spain Gerald L. , Lynch Stephen
Published: October 2010

Towed array measurements using the Office of Naval Research Five Octave Research Array (FORA) were made of narrowband and broadband transmissions as part of the Philippine Sea 2009 experiment (PhilSea09). Geometries between the tow-ship and the receive ship were established to investigate the spatial and temporal structure of convergence zone (CZ) propagation, as well as short range propagation, dominated by a single bottom bounce path. Estimates of the CZ width as a function of geography and local bathymetry will be given as well as coherence scales for a constant range arc (within a CZ). For the bottom bounce path, significant bottom scattering (beam-broadening) was observed and has been interpreted as out-of-plane scattering from the rough sub-surface seafloor. Numerical modeling to begin to investigate the nature of 3-D rough seafloor scattering work has been begun and will be presented. Implications for the detection processing for CZ and bottom-bounce detection will be discussed.
Space-time scales of sound-speed perturbations observed in the Philippine Sea: Contributions from internal waves and tides, eddies, and spicy thermohaline structure.
Authors: Colosi John A. , Dushaw Brian , Andrew Rex K. , Van Effelen Lora J. , Dzieciuch Matthew A. , Worcester Peter F.
Published: October 2010

The Philippine Sea is a dynamic ocean basin with complex multi-scale sound speed structure. Therefore the PhilSea09 and PhilSea10 experiments have put significant resources toward quantifying the space-time scales of this sound speed variability, so that the acoustic transmission data can be properly interpreted. In the PhilSea09 pilot study, two moorings equipped with temperature (T), conductivity (C), and pressure sensors, along with upper ocean ADCP, monitored ocean variability for a month in the Spring. The measurements reveal an energetic and nonlinear mixed diurnal-semidiurnal internal tide, a diffuse Garrett–Munk (GM) type internal wave field at or above the reference GM energy level, and a strong eddy field. One mooring which was equipped with pumped sensors for enhanced salinity (S) resolution was able to accurately quantify T and S variability along isopycnals (spice). The spice contribution to sound speed fluctuation is strong near the mixed layer but is significantly weaker than the other contributions in the main thermocline. Frequency spectra as well as vertical covariance functions will be presented to quantify the temporal and vertical spatial scales of the observed fluctuations.
Predicting mode-1, internal-tide signals in the Philippine Sea using tidal analysis of satellite altimeter data.
Authors: Dushaw Brian D. , Colosi John A. , Dzieciuch Matthew A. , Worcester Peter F.
Published: October 2010

Tidal analysis of satellite altimeter data has demonstrated that mode-1 internal tides near Hawaii have considerable predictability. Temporally incoherent contributions to mode-1 internal tides appear to be minimal, and very weak attenuation is evident. The internal-tide modes are associated functions of displacement, temperature, sound speed, current, etc. Sea-surface height is determined by the displacement mode. Whether derived from thermistors, altimetry, or acoustic tomography, the mode amplitude implies specific profiles of temperature, current, etc. The tidal analysis of altimeter data for the region of the Philippine Sea will be discussed, leading to predictions of in situ variability. These predictions will be compared to thermistor and tomographic data acquired in the Philippine Sea during the ONR-sponsored, PhilSea09 test experiment in March 2009. These data consist of month-long measurements of temperature acquired by thermistors on two moorings, affording excellent resolution of the internal-tide modes. One of these moorings hosted a 225–325-Hz swept-frequency source that transmitted tomographic signals recorded on the other mooring by a water-column-spanning, distributed vertical line array. Strong, coherent internal-tide signals, particularly mode-1, are apparent in these data. A comparison of the altimetry and in situ results tests the predictability of low-mode internal tides in the Philippine Sea basin.
Hooded pipes: Pre-Columbian and contemporary.
Authors: Rawcliffe Susan
Published: October 2010

Hooded flutes or pipes were found primarily among the prehispanic cultures of West Mexico and consist of an awning shape around three sides of the pipe’s air ducted aperture, and angling over its top. During construction, a hooded pipe’s sound can be manipulated through variations of the size and shape of the aperture, the design of the over-arching hood, and, to some extent, the flute’s body shape. Minute differences in construction can make a large difference in the timbre. A hood can limit the ability to play the harmonics of the tube, but contributes a characteristically marvelous rough, reedy timbre that can be manipulated through air pressure variations. Sonograms, recordings, photos, and measurements of a few prehispanic hooded pipes located in Fowler Museum are compared with each other and with those of a Rawcliffe hooded pipe. For contrast, the sounds and sonograms of an ancient pipe without a hood will be included. Hopefully, the results of this analysis will illustrate some sound preferences found within the prehispanic instrumentarium as well as explore some possibilities for recreating ancient sounds in contemporary flutes. Time permitting, the presentation will conclude with a brief performance on the Rawcliffe pipe.
An organological approximation of Mayan noise generators.
Authors: Rodens Vanessa , Sanchez Gonzalo
Published: October 2010

Within the versatile corpus of prehispanic sound producing instruments there is a group of wind instruments properly known as “noise generators”, “air-spring flutes”, or “Mayan clarinets”. Since their extraordinary acoustic mechanism evolved during the Classic Period (300–900 AD) by Mesoamerican or rather the Maya culture, these sound producing instruments emit very complex sounds which can be described as raspy and noisy. In Mexican and Guatemalan museums and collections, there are numerous specimens of these so-called noise generators, either unearthed during excavations or belonging to private collections, which have rarely been studied before. With this work we plan to present the acoustical and organological characteristics of different varieties found in various archaeological sites.
Mexican precious flute.
Authors: Velazquez Roberto
Published: October 2010

Forty years ago, the ceramic flute was acquired in the Tula archaeological site (700–1100) without information or data, but it was officially registered as an archaeological artifact and is beautiful, extraordinary, and has special properties and characteristics: Decorated with the face of a personage and green, white, and red colors and figures; mineralized dark spots, from accretions of insects and microbes on its surface, similar to those of ceramic from ancient shaft tombs of West Mexico; resonating tube like the chirimia; output of wind way very fine and thin of nearly 0.3 mm; plays six basic musical notes, very similar to those of the actual temperate scale with A4=440 Hz; data of fundamental frequencies fit with the least-squares method to a second-degree mathematical function; the F0 of its digitalized sounds can be drawn as several Mexican pictographs, in the frecuency domain using spectrograms; maximum acoustic radiated power of 0.004 W, similar to the level of a tenor recorder flute; and very delicate and sweet sounds with low noise signals, but can be heard up to a distance of 100 m on an open field.
Can you fit authorship of textbooks into an academic career?
Authors: Ginsberg Jerry H.
Published: October 2010

It is commonly presumed at research-oriented universities that faculty teach well, so acheivements as a teacher are not esteemed equally to research accomplishments. Authorship of textbooks is likely to be considered a teaching activity, and it seldom is valued at a level commensurate with the effort required to write a successful book. The consequence is that many faculty are reluctant to write books. This individual’s experiences in writing textbooks on classical dynamics and vibrations are counter to these observations. Rather, the activity has been a bridge between teaching and research, with unique challenges and rewards. The author will draw on his experiences to suggest a path by which others might augment their academic endeavors by writing textbooks.
Hot topics in architectural acoustics.
Authors: Ryherd Erica E
Published: October 2010

In recent years, there has been a surge of research and policy-making motivated by the grand challenges of environmental sustainability and societal health. Two hot topics in these areas that have a direct relationship to architectural acoustics are green buildings and hospitals. The green building movement centers around designing buildings that are more sustainable in order to decrease energy consumption, minimize environmental impact, and create healthier spaces for occupants. In the area of hospital acoustics, there is strong and growing evidence of the negative psychological and physiological impacts of a poor hospital soundscape on patients, staff, and visitors. Unique materials, systems, and technologies are being utilized in both green design and hospital design to satisfy the complex requirements, including unique acoustic requirements, of these spaces. Much effort is being put toward specifically incorporating acoustics into the various green building and hospital design guidelines.
Hearing protection use during military tactical operations: Not a simple solution.
Authors: Fallon Eric
Published: October 2010

It is no secret that large numbers of soldiers do not wear hearing protection during tactical operations, yet we cannot quantify the compliance rate or the most common reasons for rejection. The presenter will discuss the Army’s mantra of Shoot, Move, and Communicate, and how temporary threshold shift, background noise, and hearing protectors affect military operations. Other topics include the use of hearing to maintain situational awareness, the use of our hearing as a tool of lethality, common soldier mindsets regarding hearing protectors, and why soldiers reject standard linear hearing protectors.
Acoustic communication performance of impulse suppressing hearing protectors.
Authors: Rubin Gordon
Published: October 2010

An array of hearing protection products having acoustic impulse suppression capabilities are currently on the market. Level-dependent hearing protectors which suppress impulsive noise are already being issued for use in combat situations (i.e., by soldiers, law enforcement). The effects of this class of hearing protection on acoustic communication is a subject which merits research at the present time. An investigation was made focusing on the performance of several off-the-shelf electronic hearing protection products, in terms of features critical to acoustic communication. In particular, spatial awareness and speech intelligibility were looked at to better understand the impact of these devices and to predict the performance of the personnel they are issued to.
Total absorption peak by use of a rigid frame porous layer backed by a rigid grating.
Authors: Groby Jean-Philippe , Dazel Olivier , Vigran Tor Erik , Lauriks Walter
Published: October 2010

The acoustic properties of a low-resistivity porous layer backed by a rigid plate containing periodic rectangular irregularities, creating multicomponent diffraction gratings, are investigated. Numerical and experimental results show that the structure possesses a total absorption peak at the frequency of the modified mode of the layer when designed as proposed in the article. These results are explained by an analysis of the acoustic response of the whole structure and especially by the modal analysis of the configuration. When more than one irregularity per spatial period is considered, either additional higher frequency peaks or additional total lower frequency peaks are observed.
Accuracy and precision of forensic voice comparison using the Chinese /iao/ triphthong.
Authors: Zhang Cuiling , Morrison Geoffrey Stewart
Published: October 2010

Some studies on forensic voice comparison have fitted parametric curves to the formant trajectories of diphthongs spoken in controlled phonetic environments and obtained results with a high degree of validity. The present study fits parametric curves to the formant trajectories of tokens of the Standard-Chinese /iao/ triphthong extracted from telephone conversations, in which there was no control over the phonetic context. Two non-contemporaneous recordings from each of 60 female speakers were analyzed. Likelihood ratios were calculated for a test set in which some comparisons are known to be same-speaker comparisons and others known to be different-speaker comparisons. The accuracy and precision (validity and reliability) of the test results were calculated using the log-likelihood-ratio cost (Cllr) and an estimate of their 95% credible interval, respectively.
Forensic voice comparison based on nasal formants.
Authors: Wang Alejandro
Published: October 2010

One of the main problems faced in forensic voice comparison is voice disguising, with its more intuitive executions carried out through lowering F0, producing falsetto, or nose picking. For the first two ways of disguise, analyzing nasal formants could be relevant as normally nasal cavities are not modified by the suspects. A formant detector was developed in order to accurately detect these formants either on nasal consonants or on nasalized vowels from two non-contemporaneous recordings from 30 Spanish male speakers. The recorded samples were compared within the likelihood-ratio framework; the results were validated through the log-likelihood-ratio cost function (Cllr).
Statistics of acoustic normal mode energy for low frequency long range propagation in the ocean: Comparisons between observations and theory.
Authors: Chandrayadula Tarun K. , Colosi John A. , Worcester Peter F. , Dzieciuch Matthew A. , Mercer James A. , Howe Bruce M. , Andrew Rex K.
Published: October 2010

The Long Range Ocean Acoustic Propagation EXperiment (LOAPEX) carried out 75-Hz broadband transmissions at source depths of 800 m (on the sound channel axis) and 350 m to ranges of 50, 100, 250, 500, 1000, 1600, 2300, and 3200 km. These transmissions were received on a vertical array capable of resolving the first 10 acoustic normal modes. The observed mode energy distributions as a function of range are strongly related to the amount of internal wave scattering occurring across range. A fundamental question is the predictability of the energy distributions from scattering theory and estimates of ocean internal wave spectra. Transport equations utilizing small angle forward scattering and the Markov approximation have been derived to describe the range evolution of cross-mode coherence [J. Acoust. Soc. Am. 126, (2009)]. The theory agrees well with Monte-Carlo simulations suggesting that the scattering physics is well known. The LOAPEX observations are an excellent opportunity to test the predictive ability of the transport equations using real data. Issues in the model/data comparisons involve uncertainties in the internal wave spectrum and small sample sizes from LOAPEX. [Research performed while the author held a National Research Council Research Associateship Award at Naval Postgraduate School.]
Antipodal acoustic propagation (Australia-Bermuda) in the high-resolution global ocean state estimate.
Authors: Dushaw Brian D.
Published: October 2010

In 1960, the sound signals from a sequence of 300-lb TNT shots deployed off Perth, Australia were recorded at Bermuda. The acoustic propagation of these signals are examined using ECCO2 1/6 degree ocean state estimates [1992–2006; www.ecco2.org] and Smith-Sandwell 1’ global topography. Only the first acoustic mode need be considered. Intense, small-scale features (e.g., Agulhas rings, the Antarctic circumpolar current) greatly influence the acoustic paths, giving them a scintillating and time-dependent nature. Previous analyzes found, in the absence of the influence of the sea floor, Bermuda to be in the acoustic shadow of the African continent. The oceanic features of ECCO2 are sharper, hence more refractive, than the smoothed ocean atlases previously employed, but the additional refraction still does not give “direct” arrivals. The “direct” arrivals miss Bermuda by only 135±52 km, however. Scattering from Kerguelen and the Crozets, and reflection from the eastern tip of South America are sufficient to account for the 1960 measured arrivals. Intensity considerations show that because Bermuda was shadowed, the recorded signal levels of the explosive shots (15 dB RE noise) were greatly reduced compared to theoretically expected signal levels (30 dB RE noise).
Investigation of the subjective impression of listener envelopment with both binaural recordings and auralizations.
Authors: Vigeant Michelle C. , Celmer Robert D. , Ford Madison D. , Vogel Carl K.
Published: October 2010

Listener envelopment (LEV) is the sense of being fully immersed in a sound field and can be used to compare the listening experience in different concert halls. LEV has been shown to correlate with the objective parameter late lateral sound level (GLL) through the use of simulated sound fields generated with delays and reverberators. The primary purpose of this study was to investigate this correlation using both binaural recordings made in a 900-seat hall and auralizations made in an ODEON v9.20 model with both measured and predicted GLL values. In addition, the ratings of the actual recordings and simulations were compared to determine equivalency. A subjective study was carried out using 35 musically trained test participants who rated 24 stimuli, which varied as a function of both receiver position and hall setting. The ratings of the binaural recordings were found to have a linear correlation with both the measured and simulated GLL values, while the ratings of the auralizations were not found to have a clear linear relationship with GLL. When the ratings of the recordings and auralizations were compared, however, only two cases were found to be significantly different. [Work supported by a University of Hartford Greenberg Junior Faculty Grant.]
Real-time interactive room acoustic simulation engine using graphics processors.
Authors: Cheng Zuofu , Haken Lippold
Published: October 2010

Presented is a software system for real-time simulation of acoustic spaces on consumer graphics technology. This is an API that uses modern graphics processing units (GPUs) to derive the high-order reflected and transmitted paths to a stereo listener from multiple sound sources within a room of arbitrary geometry and wall properties. The system processes the entire audio chain on the GPU, computing the listener’s stereo mix from raw input waveforms stored in video memory and a polygonal room model and material and scene description. For the intended application which is video game audio, the room acoustics are computed at 15–30 frames/s and interpolated to account for fast listener or source motion to coincide with the graphics rendering, which may be done concurrently on the same processor. Provisions are provided within the API for dynamic rooms to handle gameplay elements such as doors, platforms, and physically modeled objects. An acoustic scene editor is presented, which also uses the API to simulate a first person game environment.
Structure and contexts in the long distance calls of Alouatta clamitans and Alouatta belzebul.
Authors: Oliveira Dilmar , Ades Cesar
Published: October 2010

The structure of the long range calls of howler monkeys, primates of the genus Alouatta, is scarcely understood in relation to the functions they assume. Records of Alouatta clamitans and Alouatta belzebul long distance calls were obtained at different Brazilian sites. The long distance calls of both species are low-frequency, harsh, loud sounds, uttered in sequences that may last several minutes. There is wide gradation both within and between call categories. The structure of roars and barks seems to serve different roles: barks function as graded signals of alarm, roars as resource holding potential signals used in resource defense. Observations in A. clamitans give support to such hypotheses. Roar use and structure have the most marked differences between these species. A dawn chorus of roaring was observed only for A. belzebul, which probably has a more spontaneous emission of roars, while A. clamitans use roars mainly in intergroup encounters. The structural divergence between the long range calls of these species may reflect species–typical adaptations. The presence of both brief and continuous roars in both species, but not in the most basal Alouatta palliata can bring cues to loud calling evolution in howlers. [Work supported by CNPq, FAPESP, IF/SP, FURB, CEPESBI, IBAMA/PB, and Fazenda Pacatuba.]
Acoustic behavior in crocodilians.
Authors: Britton Adam R. C.
Published: October 2010

Sound production in reptiles is generally limited in scope, yet crocodilians have developed a modest repertoire of vocal and non-vocal acoustic signals to convey a range of different information. This ability is perhaps less surprising considering that their Archosaur heritage is shared with dinosaurs and birds, and basic similarities to avian bioacoustics are apparent. An overview is presented of sound production and reception in crocodilians, the sound characteristics and repertoire of known signals, and the important role that these signals play in crocodilian behavior. The evolution of bioacoustics in this group is touched upon, based on biological and behavioral evidence between species.
Tapir vocalizations: A comparison with equines and other perissodactyls.
Authors: Browning David G. , Herstein Peter D.
Published: October 2010

The perissodactyls (odd-toed ungulates) comprised of equines, rhinos, and tapirs have vocalizations during which the frequency spectra can change, in contrast to the artiodactyls (even-toed ungulates), comprised of cows, sheep, deer, etc., whose vocalizations are primarily tonals. This suggests that a simple vocal expression by perissodactyls may be possible, and a recent study of horse whinnies under different conditions indicates that this may be the case. The vocalizations of tapirs, perhaps the least studied members of this group, are compared to those of equines and rhinos.
The acoustic ecology and behavior of minke whales (Balaenoptera acutorostrata) near tropical and subtropical North Pacific Islands.
Authors: Norris Thomas , Yack Tina M. , Martin Stephen , Oswald Julie N. , Cummins Amanda J. , Thomas Len
Published: October 2010

Passive acoustic monitoring, acoustic localization and acoustic/visual line-transect surveys of minke whales were conducted near the Hawaiian and Marianas Islands between 2006 and 2010. Acoustic data were collected using (1) towed hydrophone arrays deployed off Kauai and the Marianas Islands, (2) seafloor hydrophones from the U.S. Navy’s Pacific Missile Range Facility (PMRF) northwest of Kauai, (3) the Aloha Cabled Observatory (ACO) seafloor hydrophone northwest of Oahu, and (4) HARP autonomous recorders deployed off the Northwest Hawaiian Island Chain. Significant differences were detected in the pulse repetition rates of boings recorded in Hawaiian versus the Marianas Islands. This information is being used to assess the population characteristics of North Pacific minke whales. Analysis of ACO recordings indicates seasonal patterns, but not diurnal patterns in the number of boings detected. We are in the process of estimating the abundance of vocalizing animals in the main Hawaiian and Northern Marianas Islands study sites using towed hydrophone array data. These results will be compared to estimates made with the PMRF hydrophone data using spatially explicit capture-recapture methods. Results of these studies are providing a better understanding the acoustic ecology and behavior of minke whales in low-latitude breeding areas of the North Pacific. [Work supported by ONR.]
Vocal activity of tropical dolphins is inhibited by the presence of killer whales, Orcinus orca.
Authors: Rankin Shannon , Archer Eric , Oswald Julie
Published: October 2010

Research has suggested killer whale predation may affect cetacean vocal behavior; however, few data exist to test this hypothesis. Data collected for 19 609 km of visual and acoustic shipboard surveys in the tropical Pacific Ocean were examined to determine if changes in dolphin vocal activity could be attributed to the presence of killer whales. These surveys included 346 detections of three highly vocal dolphin species (genus Stenella), whose whistles can be detected at ranges over 4.6 km. Random forest analysis was used to model vocal behavior based on sea state, visibility, fog/rain, thermocline temperature/depth, mixed layer depth, chlorophyll, distance-to-shore, species, group size, perpendicular distance, and presence of killer whales. Our results show that the presence of killer whales significantly inhibited vocal activity in these tropical dolphins (p = 0.02). Killer whales are rare in the tropics, and this disruption in communication may not have a significant impact on interactions necessary for survival. However, in temperate climates, where increased productivity supports a greater abundance of killer whales, this interruption in communication may have a greater impact. The lower incidence of whistling dolphins in temperate waters may be related to the greater abundance of killer whales in these areas.
Analysis of the interaction of acoustic waves with hard and soft corals in the near field of a source.
Authors: Hastings Mardi C.
Published: October 2010

Hard and soft corals exist in tropical and sub-tropical regions usually within 25–70 m of the surface. They are invertebrates with a mouth, tentacles, nematocysts, and simple sensory organs and nervous systems. Reef-building corals live in bottom-attached colonies and depend on moving water for transport of nutrients and removal of waste products. The physical characteristics of their bodies that promote interaction with flowing water also enhance fluid dynamic forces. Thus in the near field of a powerful acoustic source, the instantaneous drag, lift, and acceleration forces imposed on a coral reef have the potential to cause injury. An analysis of the fluid dynamic forces generated by an air gun blast was used to estimate stresses induced in stony coral skeleton and polyp tissues as a function of colony size. The stress at which injury is expected was calculated by applying a factor of safety of 2 to available values for rupture strength of stony coral skeleton and longitudinal strength of polyp connective tissue. Results indicate that polyps in colonies with characteristic length of about 5 m are likely to be injured by an air gun blast when the peak-to-peak received level exceeds 260 dB re 1 μPa.
High precision histotripsy treatment using active preconditioning of cavitation nuclei.
Authors: Cain Charles , Wang Tzu-Yin , Xu Zhen
Published: October 2010

Histotripsy is an ultrasound therapy that mechanically disrupts soft tissue using cavitation bubble cloud. The histotripsy process results in a damaged zone with size and shape matching those of the focal volume. Recent studies have shown that the damaged zonecan be further confined to a region substantially smaller than the focal volume using a cavitation nuclei preconditioning pulse sequence delivered to the periphery of the focus before each therapy pulse. To investigate the underlying mechanism, we studied the cavitation activity and the corresponding damage in a red blood cell-gel tissue phantom. The tissue phantom consists of an agarose hydrogel with red blood cells embedded in a thin central layer. As red blood cells were damaged, local transparency would increase in the damaged zone. This phantom allows for direct observation of both the cavitation bubble cloud and the treatment outcomes in real time. Using high speed photography, we have discovered that the nuclei preconditioning pulses appear to destabilize cavitation nuclei from the periphery within a few tens of pulses. Significant cavitation damage was, therefore, prevented in the periphery. This study demonstrates the feasibility of local cavitation suppression using cavitation nuclei preconditioning. This approach allows active protection of adjacent critical structures.
Passive mapping for real-time monitoring of ultrasound therapy.
Authors: Coussios Constantin C. , Gyongy Miklos , Ritchie Robert , Webb Ian , Nandlall Sacha , Jackson Edward , Arvanitis Costas , Bazan-Peregrino Miriam , Arora Manish
Published: October 2010

Arrays of detectors placed co-axially with a therapeutic transducer make it possible to receive the high-frequency emissions produced by tissue during therapeutic ultrasound excitation with high sensitivity and in real time, whether in the presence or absence of cavitation activity. The signals received by the array of receivers can be decomposed into broadband, harmonic, and ultraharmonic components and combined using recently developed passive mapping techniques to produce real-time maps of inertial cavitation, stable cavitation, boiling, and of regions of tissue where the high-frequency ultrasonic response changes significantly. In the context of high-intensity focused ultrasound ablation, passive mapping of inertial cavitation makes it possible to visualize the focus in real time, whilst mapping of boiling can identify regions of over-treatment. Further analysis of changes in the harmonic component of high-frequency emissions in the presence or absence of cavitation can also provide reliable detection of the change in viscoelastic tissue properties that corresponds to successful ablation. In the context of ultrasound-enhanced drug delivery, cavitation mapping can help identify the tissue regions where successful extravasation of therapeutic agents from blood vessels has occurred. It is concluded that passive mapping could provide a novel, effective, and low-cost method for real-time guidance and monitoring of ultrasound therapy.
Acousto-optic sensing for the real-time monitoring and feedback control of non-cavitating high-intensity focused ultrasound lesion formation in optically diffuse tissues.
Authors: Roy Ronald A. , Lai Puxiang , McLaughlan James R. , Draudt Andrew B. , Cleveland Robin O. , Murray Todd W.
Published: October 2010

The acoustic monitoring of non-cavitating high-intensity focused ultrasound (HIFU) lesions is challenging due to the relatively weak acoustic contrast between normal and necrosed tissues. Fortunately, thermal lesions posses optical scattering and absorption characteristics that can differ significantly from surrounding tissue. Diffusive optical techniques such as photo-acoustic imaging and diffusive optical tomography have been successfully employed to image absorbing structures in organs such as breast and brain. We describe a technique in which the nonlinear interaction of diffuse laser light (1064 nm) and the HIFU field is used to sense the onset and spatial extent of lesion formation in excised chicken breast. Changes in AO response correlate with lesion volume. We show that the AO signal can be used to provide real-time feedback in order to control the duration of the HIFU exposure. The lesions that were formed with AO feedback had a more consistent volume than lesions formed with a fixed duration of HIFU [Work supported by the Center for Subsurface Sensing and Imaging Systems (NSF ERC Award No. EEC-9986821).]
Design and testing of an interstitial therapeutic ultrasound applicator for the thermal ablation of cerebral tumors.
Authors: Canney Michael S. , Souchon Remi , Carpentier Alexandre , Girard Flavien , Chapelon Jean-Yves , Lafon Cyril
Published: October 2010

Conventional treatments for cerebral tumors involve surgical resection of the lesion in combination with chemotherapy or radiotherapy. In this work, an alternative, minimally invasive approach is presented for thermally ablating cerebral tumors using an interstitial ultrasound transducer. Initial testing and characterization of a prototype device based on a mono-element design is presented. Heating experiments are performed in tissue phantoms and in ex vivo bovine and sheep brain. Real-time temperature monitoring and lesion characterization are performed using magnetic resonance imaging (MRI). Furthermore, obtained temperature rise and lesion volume registered on MRI are compared with numerical modeling. The results demonstrate that the prototype interstitial probes have good MRI compatibility and are capable of ablating a volume of tissue of up to several centimeters in diameter in several minutes under real-time MRI guidance. Furthermore, there is a possibility to precisely tailor the lesion volume to the treatment zone using a rotational approach. [Work supported by the ASA Hunt Fellowship and CarThéra SAS.]
Real-time passive acoustic monitoring of tissue damage during thermal ablation by high-intensity focused ultrasound.
Authors: Nandlall Sacha D. , Jackson Edward , Coussios Constantin-C.
Published: October 2010

This work proposes a novel method for monitoring tissue ablation by high intensity focused ultrasound (HIFU) in real time. The proposed method employs the passively acquired acoustic signal emitted from the HIFU focus throughout an exposure. A total of 161 exposures were performed in seven freshly excised ox livers using 1.067-MHz HIFU at a 95% duty cycle. Acoustic emissions were recorded using a 15-MHz passive detector aligned confocally and coaxially with the HIFU transducer. Lesion presence and size were ascertained by slicing the tissue in the transverse and axial focal planes post-exposure. Results demonstrate that the successful formation of HIFU lesions in ex vivo ox liver is highly correlated with the presence of pronounced dips in the magnitude of the received signal at integer harmonics of the insonation frequency. Optimization and validation of a detection algorithm based on this observation show that the detector agrees with the post-exposure lesioning assessment in 75% of cases overall, and that the error rate drops further for exposures shorter than 1 s or longer than 2 s. Such a detector could therefore provide a low-cost means of effectively monitoring clinical HIFU treatments passively and in real time.
Influence of wall vibrations on the transient sound of flue organ pipes.
Authors: Kob Malte
Published: October 2010

The question of how the vibrations of a metal flue organ pipe contribute to the perceived sound has been investigated intensively in the last decades. Numerical, experimental, and theoretical works have shown that the influence can modify fundamental frequency, amplitude, and stability of the sound. However, these changes are small in the stationary sound of a pipe and vary with boundary conditions. Fewer investigations have concentrated on the transient sound of a pipe. As one result of the research done in a project within the Gteborg Organ Art center, it was shown that due to the casting process, baroque flue organ pipes often have considerably thinner upper ends than modern pipes. To prove the influence of the wall vibration on the perceived sound, recordings of a blown pipe with and without damping of the wall have been carried out. Furthermore, investigations of eigenmodes of the pipe under test using finite element calculations and pressure and velocity measurements with force excitation at the labium with subsequent modal analysis were made. The results confirm that some structural modes are excited when the pipe is blown and some components of the transient spectra change when the pipe is damped.
Vibrations in brass instrument bodies: A review.
Authors: Hoekje Peter L.
Published: October 2010

The bodies of brass instruments vibrate when played, as evident to any player. These vibrations are driven mechanically at the player’s lips and by coupling with the internal acoustic field throughout the instrument. The coupling can equally well allow energy flow in the opposite direction, from the body to the player’s lips and to the internal acoustic field. The vibrating shell can also radiate directly into the room. Studies involving human or machine players suggest that the effect of the wall vibrations on the acoustic spectral components is of the order of a few decibels. However, for the most part, the direct radiation of the wall vibrations is approximately 20 dB below the level of the radiated internal acoustic field. The wall vibrations have a slightly different time envelope, though, and also have a formant-like region around a few kilohertz. Some of the pieces of this complex puzzle that need further investigation include the interaction between player and instrument, the effect of sound level on the coupling, the perceptibility of the radiated vibrations by auditors, and the variations within the brass family.
Discussing the effects of environmental noise upon the immune system.
Authors: Orozco Medina M. , Orozco Barocio A. , Figueroa Montaño A. , Ochoa Ramos N.
Published: October 2010

Human health relates either positively or negatively to environmental stimuli. It is well documented in science literature, how toxic substances disturb lung function and how ionizing radiation damage genetic material. In modern societies, noise is an agent entering the list of the diverse environmental stressors of urban population. Noise in the urban environment affects quality of life, as it alters interpersonal communication, sleep, and is a potential risk for hearing loss due to continuous and chronic exposure, as well as some other documented effects. Recently the response of the immune system to the effects of noise is taking importance in the scientific community. Researchers are studying and applying unconventional approaches in order to find any relationship between the amount of noise and the response of the immune system. This paper discusses evidence of the relationship among environmental noise and the immune system, and also questions the methods and techniques applied to finally propose issues to be considered when studying relationships among environmental noise and the immune system.
Ritual and noise.
Authors: Rebolloso Roberto , Elizondo-Garza Fernando J.
Published: October 2010

Starting from an ethnographic analysis of primitive rituals, the evolution of the production of noise in different kinds of rites is analyzed up to the contemporary society. The definition of rite and noise, and the concatenation of stimuli on people produced by rites that induce habits—that in a certain sense are addictive—are discussed. The use of noise in tribal, religious, sport, political, and festive rituals is described.
Twenty years of fun with resonant ultrasound.
Authors: Leisure Robert G.
Published: October 2010

Resonant ultrasound (RUS) is an elegant method for determining the elastic and anelastic properties of materials. The development of computational methods, robust computer codes, and sensitive instrumentation by a few key players has resulted in a simple, yet powerful, tool. The speaker was introduced to RUS 20 years ago. During the past two decades he, along with numerous students and in collaboration with many colleagues, has used this technique to study various problems: phase transitions, texture in alloys, and the elastic and anelastic properties of several materials—hydrogen absorbing compounds and alloys, nanocrystalline materials, and quasicrystalline materials—over an extended temperature range. All of these problems would have been difficult, if not impossible, to address with conventional ultrasonic methods. A few examples—phase transitions and internal friction due to hydrogen hopping, in particular—will be used to illustrate the power of RUS.
Resonant ultrasound and high temperature superconductivity.
Authors: Boebinger Greg
Published: October 2010

The first experimental test of the 1957 Bardeen–Cooper–Schreiffer theory of superconductivity was a measurement of ultrasonic attenuation. Since then, ultrasound has been sporadically used as a probe of the fundamental physics of superconductivity. One primary difficulty in the application of ultrasonic techniques to high temperature superconductivity has been dissipation due to twin grain boundaries in the crystals. With the availability of detwinned yttrium-barium-copper-oxide superconducting single crystals, resonant ultrasound can now make precision measurements that use the fundamental connection between sound speeds and thermodynamics to explore questions relating to the nature of the so-called pseudogap state, the precursor state to superconductivity, in which preformed Cooper pairs and a strong superconducting interaction have been proposed. Because the simplistic connection from superconductivity to the bulk modulus is of the order of the square of the ratio of the superconducting transition temperature to the Fermi temperature, only high precision techniques such as resonant ultrasound spectroscopy are capable of observing the expected—but small—signatures.
Pitch comparisons between cochlear-implant stimulation and sounds played to a normal-hearing contralateral ear.
Authors: Carlyon Robert P. , Macherey Olivier , Frijns Johan H. M. , Axon Patrick , Kalkman Randy K. , Boyle Patrick , Baguley David M. , Briggs John , Deeks John , Briaire Jeroen J. , Barreau Xavier , Dauman Rene
Published: October 2010

A small group of cochlear implant users, having normal hearing in the unimplanted ear, compared the pitches of electrical and acoustic stimuli presented to the two ears. Comparisons were between 1031-pps pulse trains and pure tones or between 12- or 25-pps electric pulse trains and bandpass filtered acoustic pulse trains of the same rate. Three methods (pitch adjustment, constant stimuli, and interleaved adaptive procedures) were used. For all methods, we showed that the results can be strongly influenced by non-sensory biases arising from the range of acoustic stimuli presented, and proposed a series of checks that should be made to alert the experimenter to those biases. We then showed that the results of comparisons that survived these checks do not deviate consistently from the predictions of a widely used cochlear frequency-to-place formula or of a computational cochlear model. In one case, the matches were reliable enough to successfully reveal the movement (slippage) of the electrode array. We also demonstrate that substantial range effects occur with other widely used experimental methods, even for normal-hearing listeners.
Transformation acoustics and elastodynamics.
Authors: Norris Andrew
Published: October 2010

The properties associated with acoustic metamaterials are usually related to the idea of spatial transformation. The acoustic magnifying hyperlens [Li et al. (2009)] and the acoustic cloak are two notable examples. The basic premise is that spatial deformation can be accommodated by changes in the material properties. This is fine as long as the material properties are mapped into new ones that are physically realistic. Often, however, the transformed material no longer lies within the original class of constitutive relations of linear acoustics. This talk will describe how acoustics and elastodynamics transform to produce new material behavior. The transformed acoustic material is not unique and can be, at one extreme, an anisotropic inertial fluid and, at the other, a pentamode material. Transformed elastic materials are even more general in their constitutive behavior. However, for SH waves in elasticity, the transformation implies another elastic material—in this case, just an orthotropic material. These ideas will be illustrated by application to cloaking of acoustic and elastic waves.