bluuebunny/crossref_metadata_2025 huggingface dataset:
Extreme variations in skull density of toadfish, Opsanus ta
Authors: Edds-Walton Peggy , Ketten Darlene
Published: October 2013

Gross observations of the skull in sexually mature toadfish revealed variations in bone density that appear to be most extreme in the otic capsule. Four male and one female toadfish (17–30.5 cm SL) were scanned to obtain images formatted at 100 μm and 1 mm. Consecutive measurements were made from caudal of the otic capsule to the rostral edge of the otic capsule. Attenuation values were recorded from three sites on the skull (left parietal bone, parietal suture, ventral surface of the otic capsule) and along two otoliths (calcareous, associated with the sensory epithelia of the ear) within the otic capsule. In all five fish, the parietal suture had the highest attenuation. Attenuation values for the parietal bone varied with size, indicating increasing density with growth. Among all five fish, the lowest attenuations were obtained for the ventral wall of the otic capsule, with values similar to those of cartilage. In addition, the minimum values were found ventral to the saccular otolith. Given that the saccule is the primary auditory endorgan in this species [Edds-Walton et al., J. Comp. Neurol. 411, 212–238 (1999)], the co-occurrence of bone thinning in this area of the skull may have functional significance related to audition.
Structural (CT) and functional imaging (PET/SPECT) for the investigation of dolphin bioacoustics
Authors: Houser Dorian S. , Finneran James J. , Mattrey Robert , Hoh Carl , Ridgway Sam
Published: October 2013

A combination of imaging modalities was used to address physiological and anatomical questions relevant to dolphin bioacoustics. Three dolphins (Tursiops truncatus) were scanned with CT to investigate in vivo dolphin cranial anatomy. One dolphin underwent SPECT and PET scanning to investigate blood flow and metabolic activity of the cranial tissues. Air spaces were mostly contiguous and covered the periotic bone and auditory bulla dorsally and medially. Cranial air was compartmentalized by the nasal plug and constriction of the palatopharyngeus muscle. Blood flow, determined from SPECT imaging of 99Tc-bicisate distribution, was greatest in the brain, melon, and posterior fats of the lower jaw. Metabolic activity of tissues, assessed by monitoring the uptake of 18F-deoxyglucose via PET, indicated that melon and jaw fats were metabolically inert compared to the brain. Nasal cavity and sinus air volume that is reduced during diving may be replenished with lung air via the palatopharyngeus and Eustachian tube. Air covering the bulla may protect the ears from outgoing echolocation pulses and contribute to spectral and time of arrival cues. Blood flow to the melon and lower jaw fats may serve to either regulate the temperature of acoustic lipids or act as a site of counter-current heat exchange.
Statistical investigation of beam distortion by tissue inhomogeneity in tissue harmonic imaging
Authors: Yan Xiang , Hamilton Mark F.
Published: October 2013

For many patients, tissue harmonic imaging improves resolution by reducing phase distortion due to acoustic propagation through inhomogeneities in the body wall, reverberation in this layer, and artifacts due to sidelobes. Our investigation focuses on the first of these phenomena. A statistical analysis was conducted to quantify the improvement provided by tissue harmonic imaging in the presence of an inhomogeneous layer in close proximity to the source. The inhomogeneity is modeled as a phase screen of zero thickness located directly in front of the source. The fundamental beam and resulting second-harmonic generation are described in the parabolic approximation. The phase aberration is assumed to have zero mean and to be Gaussian correlated in space. For a source with Gaussian amplitude distribution, a solution requiring a double numerical integration was derived for the mean intensity of the second-harmonic beam profile in the target plane. The solution reveals the separate contributions due to the undistorted second-harmonic and the scattered component due to the inhomogeneity. The statistical solution is validated by comparison with ensemble averages of direct numerical simulations. Experiments were also conducted, the results of which confirm the advantages of tissue harmonic imaging. [Work supported by ONR.]
The role of vibrato in the perception of violin quality
Authors: Gough Colin E.
Published: October 2013

The role of vibrato in the characterization of violin tone will be considered from both a physical acoustics and perceptual viewpoint. Musical examples of individual waveforms from violins of widely different qualities will be used to demonstrate the importance of vibrato and other temporal fluctuations in the recognition of the violin as a specific musical instrument and, by inference, of its perceived tonal quality also. Dynamic physical models will be introduced to describe the waveforms of sounds produced by the bowed string when vibrato is used. The sound produced by an individual instrument will be shown to be critically dependent on both the positions and the Q values of the acoustically important resonances excited, in addition to random noise generated by the bowing action. It will be argued that the temporal fluctuations in the sound of a violin played with vibrato are just as important as the temporal fluctuations associated with the very strong frequency-dependence of the directivity of the violin. Weinreich has emphasized the importance of the latter effect in any realistic reproduction of the sound of a violin.
Unusual motions of a vibrating string
Authors: Hanson Roger J.
Published: October 2013

The actual motions of a sinusoidally driven vibrating string can be very complex due to nonlinear effects resulting from varying tension and longitudinal motion not included in simple linear theory. Commonly observed effects are: generation of motion perpendicular to the driving force, sudden jumps in amplitude, hysteresis, and generation of higher harmonics. In addition, these effects are profoundly influenced by wire asymmetries which in a brass harpsichord wire can cause a small splitting of each natural frequency of free vibration into two closely spaced frequencies (relative separation ∼0.2% to 2%), each associated with transverse motion along two orthogonal characteristic wire axes. Some unusual resulting patterns of complex motions of a point on the wire are exhibited on videotape. Examples include: sudden changes of harmonic content, generation of subharmonics, and motion which appears nearly chaotic but which has a pattern period of over 10 s. Another unusual phenomenon due to entirely different causes can occur when a violin string is bowed with a higher than normal force resulting in sounds ranging from about a musical third to a twelfth lower than the sound produced when the string is plucked.
Sound radiation by violins radically modal
Authors: Bissinger George
Published: October 2013

Following a radically modal path pioneered by Gabi Weinreich in the early 1980s, normal-mode vibration and radiation analysis was applied to quality-rated violins. Being able to describe the violin in terms of normal-mode behaviors leads directly to a violin equation, allows extraction of a critical frequency for the violin, provides estimates of the fraction of vibrational energy radiated and extends to modal-average trendline modeling of the acoustic output, all of which can be linked to violin quality classifications if desired. Some quality-related results mirror Weinreich’s conclusions from inverse radiativity measurements on violins, i.e., there is little difference in the radiativity of good and bad violins below 1 kHz. The first corpus bending modes (the baseball modes), first identified by Gabi and Eric Arnold, are a major contributor to violin sound and highlight one of the important aspects of Gabi’s research, the coupling between wood and air. The first near-field acoustic holography results indicate that a significant part of the radiation from these structural modes is from the f-holes of the violin. These normal-mode investigations reflect some of the importance of Gabi’s work for modern violin acoustics. [Research supported by NSF.]
Exact formula for the sound scattering cross section per unit volume in a turbulent atmosphere
Authors: Ostashev Vladimir E. , Goedecke George H.
Published: October 2013

The sound scattering cross section per unit volume is one of the most important statistical characteristics of a sound wave propagating in a turbulent atmosphere. In the literature, a formula for the sound scattering cross section is derived from an equation for a sound wave propagating in an atmosphere with temperature and velocity fluctuations. Such an equation is obtained from a complete set of linearized equations of fluid dynamics using some approximations. Thus, the classical formula for the sound scattering cross section is intrinsically approximate. In the present paper, sound scattering in a turbulent atmosphere is studied starting from the complete set of linearized equations of fluid dynamics. This approach results in an exact formula for the sound scattering cross section. The exact formula accounts for sound scattering by pressure fluctuations and by the divergence of velocity fluctuations while the classical formula does not. It follows from the exact formula that, in a dry air, a sound wave is scattered at 90 degrees only by pressure fluctuations. This result can be used as a basis for a new remote sensing technique for measuring pressure fluctuations in the atmosphere. [Work supported by the U.S. Army Research Office Grant No. DAAG19-01-1-0640.]
Eddy-size decomposition of the scattering cross section using quasi-wavelets
Authors: Wilson D. Keith , Ostashev Vladimir E. , Goedecke George H. , Auvermann Harry J.
Published: October 2013

Unlike traditional Fourier spectral representations, quasi-wavelets (QWs) describe the structure of turbulence with spatially localized functions. As a result, QWs are particularly well suited to examining the dependence of a turbulent scattering process on the size and spatial location of the eddies. In this paper, the scattering cross section for QWs of an individual size class is derived. It is shown that previous results for the von Kármán spectrum can be reproduced when the scattered energies from a continuous distribution of QW sizes are combined. A Bragg resonance condition is derived for the eddy size that scatters most strongly for a given acoustic wavenumber and scattering angle. An example application of QWs to scattering over noise barriers shows that, for a typical barrier geometry, most of the scattered energy originates from eddies in the size range of approximately one-half to twice the size of the eddies responsible for maximum scattering.
Time-domain boundary conditions for outdoor ground surfaces
Authors: Collier Sandra L. , Ostashev Vladimir E. , Wilson D. Keith , Marlin David H.
Published: October 2013

Finite-difference time-domain techniques are promising for detailed dynamic simulations of sound propagation in complex atmospheric environments. Success of such simulations requires the development of new techniques to accurately handle the reflective and absorptive properties of a porous ground. One method of treating the ground boundary condition in the time domain [Salomons et al., Acta Acust. 88, 483–492 (2002)] is to use modified fluid dynamic equations, where the ground is considered as a porous medium described by its physical properties. However, this approach significantly increases computation time, as the domain must be extended into the ground and a large number of grid points are needed. Standard impedance models for the ground boundary condition are frequency-domain models, which generally are non-causal [Y. H. Berthelot, J. Acoust. Soc. Am. 109, 1736–1739 (2001)]. The development of a time-domain boundary condition from these models requires removing the singularity from the impedance equation when transforming from the frequency domain to the time domain. Alternatively, as the impedance boundary condition is a flux equation, a time-domain boundary condition can be derived from first principles, using the physical properties of the ground. We report on our development of a time-domain ground boundary condition.
Modeling of secondary sonic booms: Influence of the variability of the atmosphere
Authors: Dallois Laurent , Blanc-Benon Philippe , Scott Julian
Published: October 2013

The shock waves generated by a supersonic aircraft are reflected in the upper part of the atmosphere. Back to the ground, they are indirect sonic booms called secondary sonic booms. The recorded signals of secondary sonic booms show a low amplitude and a low frequency. They sound like rumbling noises due to amplitude bursts. These signals strongly depend on the atmospheric conditions, in particular to the amplitude and to the direction of the wind in the stratopause. The propagation of the secondary sonic boom is studied using atmospheric models up to the thermosphere. By solving temporal ray equations, the secondary carpet position is investigated. An amplitude equation including nonlinearity, absorption, and relaxation by various chemical species is coupled to the ray solver in order to get information on the amplitude and on the frequency of the sonic boom at the ground level. Using this propagation model and the atmospheric model, the seasonal dependencies of the secondary sonic boom are investigated. Multipath arrivals are directly linked to wind field or 3-D inhomogeneities. They have been of special concern as a way to explain the rumble noise as a summation over different ray contributions.
Forest physical sampling strategies for investigating noise mitigation benefits
Authors: Guertin Patrick J. , White Michael J.
Published: October 2013

Acoustic attenuation rates in tree stands have been seen to vary considerably between measurements in various settings, with little hint as to the controlling mechanisms. Usual descriptors for a forest include tree species, stand age, and basal diameter per land surface area, properties that may not correlate with acoustic attenuation rates. As part of a recent forest attenuation measurement, we developed a forest sampling regimen aimed at indicating and distinguishing between three candidate effects: (1) scattering by resilient, wood material, (2) scattering by more compliant, leaf material, (3) refraction by canopy microclimate influence. Estimates of the wood material were made by an established point sampling process, in which significant tree trunks subtend a minimum angle at breast height. Canopy microclimate effect was characterized using percent optical closure of the upper canopy, canopy thickness, and ground vegetation height. Digital photographs aimed outward in four cardinal directions from each sample point were processed to segregate percentages of wood material, leaf material, and sky. We are currently exploring the connection between these parameters and measured attenuation rates in a single stand of woods. We propose that these parameters could offer improved correlation with measured attenuation rates between forests.
On the reconstruction of sound field using the equivalent source modeling
Authors: Ih Jeong-Guon , Jeon In-Youl
Published: October 2013

The sound field radiated from a vibrating structure is reconstructed by using the equivalent source modeling. In this method, the equivalent multipole sources which are similar to the spherical harmonics in the Helmholtz equation least-squares (HELS) method are distributed over or inside a vibrating surface. To improve the accuracy and usefulness, the effective independence (EfI) method is used to determine the optimal position of equivalent sources and the regularization scheme is adopted to determine the optimal expansion number of spherical harmonics and to suppress the high order poles. After regenerating field pressures using those optimized equivalent source modeling, the vibrating source is effectively reconstructed with minimal measurement combining the proposed method with the near-field acoustic holography (NAH) using the inverse boundary element method (BEM). In this study, an application example of a commercial vacuum cleaner using the equivalent source modeling will be demonstrated. [Work supported by the BK21 project and NRL.]
What are the statistics in statistical learning?
Authors: Holt Lori L. , Lotto Andrew J.
Published: October 2013

The idea that speech perception is shaped by the statistical structure of the input is gaining wide enthusiasm and growing empirical support. Nonetheless, statistics and statistical learning are broad terms with many possible interpretations and, perhaps, many potential underlying mechanisms. In order to define the role of statistics in speech perception mechanistically, we will need to more precisely define the statistics of statistical learning and examine similarities and differences across subgroups. In this talk, we examine learning of four types of information: (1) acoustic variance that is defining for contrastive categories, (2) the correlation between acoustic attributes or linguistic features, (3) the probability or frequency of events or a series of events, (4) the shape of input distributions. We present representative data from online speech perception and speech development and discuss inter-relationships among the subgroups. [Work supported by NSF, NIH and the James S. McDonnell Foundation.]
Bayesian approaches to perception
Authors: Diehl Randy L. , Sullivan Sarah C.
Published: October 2013

The concepts of Bayesian statistical decision theory have recently transformed research in perception by providing a rigorous mathematical framework for representing the statistical properties of the environment, for describing the tasks that perceivers perform, and for deriving computational theories of optimal performance on those tasks. Such computational theories (ideal observers) offer an appropriate benchmark for evaluating human performance, and, moreover, they can be modified to yield an excellent starting point for developing testable models. Unlike theories that focus on the role of invariant information for perceived events, the Bayesian approach treats information as probabilistic. The approach is illustrated for cases in which listeners learn to categorize artificial stimulus sets whose statistical properties (prior probabilities and stimulus likelihoods) are controlled by the experimenter. Prospects for extending the Bayesian framework to the analysis of speech perception are discussed in light of the recent progress in developing ideal observers for natural environmental stimuli. A necessary but daunting task will be the measurement of probability distributions that characterize natural speech categories. [Work supported by NIDCD.]
Early language acquisition: Statistical learning and social learning
Authors: Kuhl Patricia K.
Published: October 2013

Infants are sensitive to the statistical patterns in language input, and exposure to them alters phonetic perception. Our recent data indicate that first-time exposure to a foreign language at 9 months of age results in learning after only 5 h, suggesting a process that is fairly automatic, given natural language input. At the same time, it appears that early phonetic learning from natural language may be constrained by the need for social interaction. Our work demonstrates that infants learn phonetically when exposed to a live, but not a pre-recorded, speaker. This talk will focus on statistical learning in a social context and develop the thesis that this combination provides an ideal situation for the acquisition of a natural language.
Statistical modeling of infant-directed versus adult-directed speech: Insights from speech recognition
Authors: Kirchhoff Katrin , Schimmel Steven
Published: October 2013

Studies on infant speech perception have shown that infant-directed speech (motherese) exhibits exaggerated acoustic properties, which are assumed to guide infants in the acquisition of phonemic categories. Training an automatic speech recognizer on such data might similarly lead to improved performance since classes can be expected to be more clearly separated in the training material. This claim was tested by training automatic speech recognizers on adult-directed (AD) versus infant-directed (ID) speech and testing them under identical versus mismatched conditions. 32 mother–infant conversations and 32 mother–adult conversations were used as training and test data. Both sets of conversations included a set of cue words containing unreduced vowels (e.g., sheep, boot, top, etc.), which mothers were encouraged to use repeatedly. Experiments on continuous speech recognition of the entire data set showed that recognizers trained on infant-directed speech did perform significantly better than those trained on adult-directed speech. However, isolated word recognition experiments focusing on the above-mentioned cue words showed that the drop in performance of the ID-trained speech recognizer on AD test speech was significantly smaller than vice versa, suggesting that speech with over-emphasized phonetic contrasts may indeed constitute better training material for speech recognition. [Work supported by CMBL, University of Washington.]
Constrained maximum consistency multi-path mitigation
Authors: Smith George B.
Published: October 2013

Blind deconvolution algorithms can be useful as pre-processors for signal classification algorithms in shallow water. These algorithms remove the distortion of the signal caused by multipath propagation when no knowledge of the environment is available. A framework in which filters that produce signal estimates from each data channel that are as consistent with each other as possible in a least-squares sense has been presented [Smith, J. Acoust. Soc. Am. 107 (2000)]. This framework provides a solution to the blind deconvolution problem. One implementation of this framework yields the cross-relation on which EVAM [Gurelli and Nikias, IEEE Trans. Signal Process. 43 (1995)] and Rietsch [Rietsch, Geophysics 62(6) (1997)] processing are based. In this presentation, partially blind implementations that have good noise stability properties are compared using Classification Operating Characteristics (CLOC) analysis. [Work supported by ONR under Program Element 62747N and NRL, Stennis Space Center, MS.]
Spherical wave effects in sediment reflection coefficients
Authors: Camin H. John , Isakson Marcia J.
Published: October 2013

Several research institutions are investigating models to properly describe high frequency, sandy-sediment, acoustic properties because of their importance in shallow water operations. In this talk we will focus on the error contribution of spherical wave effects on each of four common models: the visco-elastic model, the Effective Density Fluid Model (EDFM), Buckinghams micro-sliding model and the Biot/Stoll poro-elastic model. This will be accomplished by comparing the known models of reflection coefficients to laboratory measurements. Theoretical data will be calculated for each of the models using OASES, which utilizes the depth-dependent Green’s function and a direct global matrix approach to calculate the full field. Parameters for the visco-elastic model have been measured and verified at the test location. Parameters for the EDFM, Buckingham and Biot/Stoll models were determined from measured values and previous inversions of plane wave reflection data taken at the same location. Air/water interface data will be measured and computed for each model as a test case. Linearly Frequency Modulated (LFM) chirps over the range of 30–160 kHz will be used to establish ranges in frequency. [Work supported by ONR, Ocean Acoustics.]
A comparison of high-frequency plane-wave reflection coefficient data taken from a smooth sand/water interface with current models
Authors: Worley Andrew , Isakson Marcia
Published: October 2013

Dispersion and attenuation data have shown that a fluid model or visco-elastic model is not adequate to describe acoustic interactions in littoral environments. This study will compare laboratory reflection data to five models: the visco-elastic model, the Biot–Stoll poro-elastic model, the effective density fluid model (EDFM), the Buckingham micro-sliding model, and the Biot–Stoll squirt flow + shear model (BISQS). The BISQS model allows for frequency dependence in the frame bulk modulus and the frame shear modulus by considering the squirt flow effects and grain shearing effects at the sand grain interfaces. This model has been shown to produce good agreement with in situ dispersion and attenuation data; however, it has not yet been compared to reflection data. A simulated annealing inversion algorithm with rotated coordinates will be used. Special emphasis has been placed on quantifying the effects of the statistical nature of the data on the inversion outcome. [Work supported by ONR, Undersea Signal Processing, John Teague.]
Experimental study of the poroelastic behavior of a sandy sediment
Authors: Yargus Michael W. , Jackson Darrell R.
Published: October 2013

Reflection measurements were conducted on water-saturated sand over the frequency range 200–300 kHz. Three reflection boundaries were used: water-sand, pressure-release-sand, and acrylic-sand. A reflection ratio technique was used to remove unknown calibration and geometric factors, permitting measurement of parameters relating to the Biot fast wave and bounding of parameters of the slow wave. The interpretation of these results was facilitated by use of a mechanical model. Measured (or bounded) parameters include acoustic impedances, effective densities, wave speeds (phase velocities), effective pressures, fluid-frame displacement ratios, pressure reflection coefficients, and material moduli. The acoustic impedance divided by the phase velocity provides the ‘‘effective density’’ [K. L. Williams, J. Acoust. Soc. Am. 110, 2956–2963 (2001)] for the fast wave. As expected, the effective density was less than the total density of the sediment (effective density =89% of total). The fluid-frame displacement ratio was 2.2 for the fast wave. These results provide strong evidence for the importance of Biot effects in water-saturated sand.
Geoacoustic inversion of a shallow fresh-water environment
Authors: Stotts Steven A. , Knobles David P. , Koch Robert A. , Piper James N. , Keller Jason A.
Published: October 2013

A recent experiment was conducted at The University of Texas/Applied Research Laboratories test station located at Lake Travis, Austin, TX. Implosive (light bulb), explosive (firecracker), and tonal sources were recorded on a dual receiver system located on the bottom next to a range-independent underwater river channel. Inversion results of the broadband time series obtained over ranges less than 1.5 km were used to predict measured transmission loss at several tonal frequencies in the band from 250–1000 Hz. The average water depth was approximately 38 m along the channel during the experiment. Sound speed profiles were calculated from recorded temperature readings measured as a function of depth. Implosive source spectrums were measured and used to evaluate a model/data correlation cost function in a simulated annealing algorithm. Comparisons of inversion results using both a normal mode and a ray-based plane wave reflection coefficient forward model [Stotts et al., J. Acoust. Soc. Am. (submitted)] are discussed. Predicted transmission loss based on the inversion results are compared to the measured transmission loss. Differences between fluid and elastic layer bottom models will also be presented.
Lithotripter shock interaction with a bubble trapped in an elastic tube
Authors: Szeri Andrew J. , Zhong Pei , Blake John R.
Published: October 2013

In shock wave lithotripsy, it is hypothesized that damage to blood vessels occurs through shock interaction with a bubble trapped within the vessel. This situation is investigated through a computer simulation of a three phase model: liquid, gas bubble, and nonlinear elastic vessel wall. Coupling between the three phases occurs through the pressure field evaluated at interfaces between the different media. It is found that bubble expansion and subsequent violent collapse does indeed cause considerable straining in the vessel wall, and the formation of strong jets that may lead to damage. [Research supported by the U.S. NSF Program in Biomedical Engineering.]
Physical properties and behavior of shock waves
Authors: Blackstock David T.
Published: October 2013

The distinguishing feature of a shock wave is its practically instantaneous rise in pressure. Its laws of propagation are different from those for ordinary, continuous-waveform sound waves, even when the sound wave amplitude is finite. The Rankine–Hugoniot shock relations connect the properties on either side of the shock, e.g., pressure, density, and particle velocity, with the shock velocity or Mach number. These relations are valid even for unsteady shocks, e.g., growing or decaying shocks. Weak shock theory provides a means of predicting the propagation of most steady and unsteady shocks that are encountered in acoustics, including those used in medicine. For example, in lithotripsy the focal pressure amplitude rarely exceeds 100 MPa; for such a shock the shock velocity is only ∼8% greater than the sound speed in water. Shock rise time τrise is an interesting property of shocks but often difficult to measure. For example, if the lithotripsy shock cited above was steady and in water, its rise time would be a few tens of picoseconds. When the shock is unsteady, τrise is much harder to predict.
Development of lithotripter technology
Authors: Eisenmenger Wolfgang F. W.
Published: October 2013

‘‘Squeezing’’ of the stone or cirumferential pressure of the wave propagating at the outside of the stone in the liquid or tissue results in fragmentation in planes perpendicular or parallel to the wave propagation direction. The corresponding pressure zone propagating with the sound velocity in the liquid which is below the sound velocity in the stone, causes an evanescent pressure zone in the stone resulting in tensile stress in planes parallel and perpendicular to the wave plane. A quantitative model predicting the ratio of pulses needed to fragment the stone to 2 mm particle size in relation to the number of pressure pulses needed for the first fragmentation is well in accord with experiments, supporting the ‘‘squeezing mechanism with binary fragmentation.’’ On the basis of these results it now appears possible to optimize the pressure pulse parameters measured using the Fiber Optic Probe Hydrophone (FOPH). With correspondingly optimized self-focusing electromagnetic shock wave generator systems a clinical study of the concept ‘‘wide focus and low pressure’’ ESWL was performed in a scientific cooperation between the 1. Physical Institute of the University of Stuttgart and the Xixin Medical Instruments Co., Ltd. in Suzhou, China. Literature: W. Eisenmenger, ‘‘The mechanisms of stone fragmentation in ESWL,’’ Ultrasound Med. Biol. 27, 683–693 (2001); W. Eisenmenger et al., ‘‘The first clinical results of ‘wide focus and low pressure’ ESWL,’’ Ultrasound Med. Biol. 28, 769–774 (2002).
Seismic sonar sources for buried mine detection
Authors: Baker Steven R. , Muir Thomas G. , Gaghan Frederick E. , Fitzpatrick Sean M. , Sheetz Kraig E. , Guy Jeremie
Published: October 2013

Prior research on seismo-acoustic sonar for detection of buried targets [J. Acoust. Soc. Am. 103, 2333–2343 (1998)] has continued with examination of various means for exciting interface waves (Rayleigh or Scholte) used to reflect from targets. Several seismic sources were examined for sand beach applications, including vibrating shakers, shaker devices configured to preferentially excite interface waves, linear force actuators, and arrays of shaker sources to create directional interface wave beams. Burial of some plate-like or rod-like portion of the vibrating devices was found to ensure good coupling to the beach. The preferential interface excitation device employed two degrees of freedom to mimic the two components of elliptically polarized interface waves, and was successfully demonstrated. However, it was found that at long ranges, the medium itself created two component interface waves from vibrating source radiations operating with one degree of freedom in the vertical plane. Linear force actuators were functional in this mode. An array of seven vertical shakers was utilized to create interface waves at ranges of 5 m, in the form of directional beams, some 8 deg wide at the half-power points, at frequencies around 100 Hz. Application of these devices for target detection is discussed in the companion paper. [Work sponsored by ONR.]
Effect of ground variability on the acoustic-seismic transfer function
Authors: Fokina Margarita , Fokin Vladimir , Sabatier James M. , Xiang Ning
Published: October 2013

Experimental measurements have shown that the use of a multilayered elastic media is necessary for transfer function numerical modeling. The present work deals with the effect of variability of ground properties (compressional and shear wave speeds, density, attenuation and thickness of the layers) on the acoustic-seismic transfer function (admittance). An analysis is performed on the planes of parameters of the ground in a wide frequency range for all angles of incidence. The Dunking–Throwers matrix approach is used to increase the accuracy of computations. It is revealed that the acoustic–seismic transfer function is sensitive to ground properties and small variations in the shear speed may cause a strong variation in the acoustic–seismic transfer function. Results of outdoor measurements of the acoustic–seismic transfer function are presented and a correlation between high magnitudes of the acoustic–seismic transfer function in certain frequency ranges and moisture content on the surface is revealed. A simple model explaining the correlation between the moisture content in the upper layer, acoustic–seismic transfer function and ground properties is suggested. [Work supported by ONR.]
Monitoring surface sealing and crusting of soils and glass beads using acoustic techniques
Authors: Hickey Craig J. , Broussard Greg , Sabatier James M. , DiCarlo David A.
Published: October 2013

When soils dry after a rain they form a crust or seal that changes both the stiffness and hydraulic properties of a thin surface layer which in turn effects the erodability of the soil. This soil surface crusting/sealing is examined by measuring the acoustic to seismic (A/S) transfer function on laboratory samples. An A/S transfer function measurement is a completely noncontact technique using a suspended loud speaker to impinge acoustic energy from the air onto the sample and a laser Doppler vibrometer (LDV) measures the surface particle velocity. Therefore, this technique measures the seismic energy that has been transferred into the soil from the airborne wave. Several soil samples have been investigated. Also, glass beads, being better known samples, are also examined for dry, crusted, and sealed cases. Samples tested show a quantifiable decrease in the seismic energy transferred as the crust forms but is not as sensitive to changes in sealing. An acoustic reflection technique is proposed to measure changes in the hydraulic properties associated with sealing. These measurements are compared to a poroelastic model proposed by Denneman et al.
Poroelastic effects on media with air or water saturation
Authors: Dong Hefeng , Hovem Jens M. , Hygen Hans Olav
Published: October 2013

The Biot theory predicts that three body waves can propagate in a porous medium, a shear wave, a fast and a slow compressional wave. This paper reports the result of an analysis in order to answer the importance of these three wave types in connection with underwater sound propagation and in air over a porous ground. Three approaches are applied: an analytical solution and frequency wave number integration technique extended to treat poroelasticity for reflection and transmission coefficients and finite difference modeling for time responses. The reflected and transmitted signals at the interface between a fluid and a porous medium for both air and water saturated cases are calculated and analyzed. This shows that conversion to a transmitted slow compressional wave is important in air saturated cases and can dominate the reflection loss. Conversion to a slow compressional wave in water saturated cases is of less importance. The transmitted slow compressional wave is in both air and water saturated cases diffusive and exists only in a very thin sheet near the interface.
Logarithmic temporal axis manipulation and its application for measuring auditory contributions in F0 control using a transformed auditory feedback procedure
Authors: Yanaga Ryuichiro , Kawahara Hideki
Published: October 2013

A new parameter extraction procedure based on logarithmic transformation of the temporal axis was applied to investigate auditory effects on voice F0 control to overcome artifacts due to natural fluctuations and nonlinearities in speech production mechanisms. The proposed method may add complementary information to recent findings reported by using frequency shift feedback method [Burnett and Larson, J. Acoust. Soc. Am. 112 (2002)], in terms of dynamic aspects of F0 control. In a series of experiments, dependencies of system parameters in F0 control on subjects, F0 and style (musical expressions and speaking) were tested using six participants. They were three male and three female students specialized in musical education. They were asked to sustain a Japanese vowel /a/ for about 10 s repeatedly up to 2 min in total while hearing F0 modulated feedback speech, that was modulated using an M-sequence. The results replicated qualitatively the previous finding [Kawahara and Williams, Vocal Fold Physiology, (1995)] and provided more accurate estimates. Relations with designing an artificial singer also will be discussed. [Work partly supported by the grant in aids in scientific research (B) 14380165 and Wakayama University.]
Quantitative measurement of the medial surface dynamics of the vocal folds using high-speed digital imaging
Authors: Doellinger Michael , Neubauer Juergen , Berry David A.
Published: October 2013

To increase our understanding of pathological and healthy voice production, the quantitative measurement of the medial surface dynamics of the vocal folds is significant, albeit rarely performed because of the inaccessibility of the vocal folds. Hence, an excised hemilarynx procedure is applied, Berry et al. recently reported such quantitative measurements along one coronal plane of the left vocal fold of a canine [J. Acoust. Soc. Am. 110, 2539–2547 (2001)]. The present work extends previous studies by capturing vibrations along the entire medial surface of the left vocal fold. The number of vertical rows of sutures used to demarcate fleshpoints was increased from one to five. An automatic algorithm for tracking vocal fold fleshpoints will be reported, along with calibration techniques, and error estimation. Preliminary results will be reported for both periodic and aperiodic vocal fold vibrations. High-speed digital imaging was performed using a Photron APX machine with a sampling frequency of 4000 Hz, a spatial resolution of 1024×512 pixels, and 256 levels of grayscale.
Bottomed acoustic array gain variability in the South China Sea
Authors: Orr Marshall , Pasewark Bruce , Wolf Stephen , Lynch James , Chiu Ching-Sang
Published: October 2013

The stratified sound speed field at the shelf break of the South China Sea is constantly perturbed by the tide and the passage of the internal tide, linear and nonlinear internal waves and associated fine structure. An 18-day acoustic propagation experiment was performed at the shelf break in May 2001 as part of the ONR supported AsiaEx experiment. A 32-element 465-m bottomed horizontal array received 300- and 500-Hz center frequency FM acoustic signals from sources moored at a range of ∼18.9 km. The temporal and spatial variability of signal coherence, the array gain variability, and residual signal gain variability has been extracted. Temporal and spatial variability of the signal coherence and array gain variability has a degree of correlation with temperature field variability measured near the source and receiver locations. These data as well as histograms of the residual array gain variability in time and space will be presented.
Directional noise and correlation of signal and noise variability in the ASIAEX South China Sea Experiment
Authors: Duda Timothy F. , Lynch James F. , Gawarkiewicz Glen G. , Chiu Ching-Sang , Wei Ruey-Chang , Abbot Phil
Published: October 2013

As part of the 2001 ASIAEX South China Sea experiment, known acoustic signals and noise were recorded for 16 days with co-located horizontal and vertical receiving arrays in 120-m depth water at the edge of the continental shelf. The location was south of China and southwest of Taiwan. Vertical and horizontal directionality of both signals and noise can be estimated using the two arrays. Directionality can be linked to vertical mode bandwidth. Furthermore, because of mode stripping effects, it can indicate the amount of mode coupling in the vicinity of the receiver. Previously, arrival time and total energy of the signals have been shown to respond to the strong nonlinear internal waves and internal tides of the area. Here, we investigate the response of noise energy and directionality to the waves, and compare with the response of signal energy and directionality. The results can be compared to the Shelfbreak PRIMER experiment in the Mid-Atlantic Bight, where signal and noise parameters recorded with a VLA were correlated. Correlation of signal and noise violates assumptions used in many signal processing algorithms.
Intensity fluctuations from deterministic and random azimuthal variability
Authors: Reilly-Raska Laurel K. , Siegmann William L. , Lynch James F. , Colosi John A. , Duda Timothy F.
Published: October 2013

Shallow-water sites for shelfbreak PRIMER and ASIAEX show substantial ocean horizontal variability arising from nonlinear internal wave trains. These relatively coherent structures strongly influence acoustic intensity observations, and deterministic propagation modeling has demonstrated their azimuthal effects. Moreover, random variations in the nonlinear internal waves, as well as processes such as linear internal wave fields, contribute to observed intensity fluctuations. Stochastic modeling is performed to show the azimuthal changes induced in the intensity fluctuations. The principal metric of interest is the scintillation index (SI), the ratio of standard deviation to mean intensities. Limiting cases of the SI are examined for examples including both nonlinear internal waves and random ocean variations. Simulations using a three-dimensional parabolic equation model [Collins, J. Acoust. Soc. Am. 94, 2269–2278 (1993)] are discussed, along with an extension of a random modal fluctuation approach [Dozier and Tappert, J. Acoust. Soc. Am. 63, 353–365 (1978)]. [Work supported by ONR.]
Shock wave induced sonoporation and gene transfer
Authors: Miller Douglas L.
Published: October 2013

During shockwave (SW) treatment, cavitation activity can be applied for cell killing. A bonus is that some surviving cells appear to be briefly permeabilized, or sonoporated, allowing them to take up large molecules including DNA. In vitro research has indicated that as the number of SW increased, survival declined exponentially but the number of sonoporated cells increased to better than 50% of survivors for 1000 SW. In vivo tests have demonstrated SW-induced tumor ablation could indeed be accompanied by the transfection of marker plasmids into mouse B16 melanoma tumors in vivo. With intratumor injection of plasmid DNA and air bubbles, significant results were obtained for only 400 SW. In a trial of cancer therapy, the effects of 500 SW combined with interleukin-12 immuno-gene therapy was observed on the progression of two mouse tumors, B16 melanoma and RENCA renal carcinoma. The combination of SW and IL-12 plasmid injection provided a statistically significant inhibition of tumor growth relative to SW alone for both tumor models, demonstrating feasibility for this treatment method. In the future, the development of intravenous gene delivery and improved transfection, together with image-guided ultrasound treatment, should lead to the clinical application of ultrasound enhanced gene therapy. [Work supported by NIH Grant No. EB002782.]
Overview of ultrasound-induced lung hemorrhage
Authors: O’Brien William D. , Simpson Douglas G. , Frizzell Leon A. , Oelze Michael L. , Zachary James F.
Published: October 2013

It is well documented that ultrasound-induced lung hemorrhage can occur in mice, rats, rabbits, pigs, and monkeys. Our own experimental studies have focused on mice, rats, and pigs as animal models. The characteristics of the lesions produced in mice, rats and pigs were similar to those described in studies by our research group and others, suggesting a common pathogenesis for the initiation and propagation of the lesions at the macroscopic and microscopic levels. Five experimental in vivo studies have been conducted to evaluate whether cavitation is responsible for ultrasound-induced lung hemorrhage. The studies evaluated the dependencies of hydrostatic pressure, frequency, pulse polarity, contrast agents and lung inflation, and the results of each study appeared inconsistent with the hypothesis that the mechanism for the production of a lung hemorrhage was inertial cavitation. Other dependencies evaluated included beam width, pulse repetition frequency, pulse duration, exposure duration, and animal species and age. The thresholds for producing ultrasound-induced lung hemorrhage, in general, were less than the FDA’s regulatory limit of a Mechanical Index (MI) of 1.9. Further, the MI does not appear to provide a risk-based index for lung hemorrhage. [Work supported by NIH Grant No. R01EB02641.]
Design of compact piezoelectric transducers for shock wave applications
Authors: Dreyer Thomas , Liebler Marko , Riedlinger Rainer E. , Ginter Siegfried
Published: October 2013

The application of focused intense sound pulses to treat several orthopedic diseases has gained in importance during the past years. Self-focusing piezoelectric transducers known from ESWL are not well suited for this purpose due to their size. Therefore compact transducers have to be designed. This implies an increase of the pressure pulse amplitude generated at the radiating surface. A stacked placement of two piezoelectric layers driven by two high-voltage pulses with an adjustable delay accomplishes this. Several designs are presented here representing transducers of different sizes. In principle piezoelectric transducers have the ability to vary the pressure pulse shape to a wider extent than other shock wave sources. Based on FEM simulations of the transducer the influence of some driving parameters, like a variation of the interpulse delay or shape of the driving voltage, on the resulting focal pressure signal is demonstrated. The results show the feasibility to control some parameters of the signal, for example the peak negative pressure amplitude. This possibility could provide new aspects in basic research as well as in clinical applications.
Determination of optimum response requrements for underwater fiber-optic and electroacoustic transducers
Authors: DeMetz Fred C.
Published: October 2013

To aid in the design of new sensors the methodology of determining the optimum sensitivity, linearity, and dynamic range requirements of underwater acoustic sensors is described. The relationships between the commonly specified ‘‘rated’’ sensitivity and its ‘‘absolute’’ detectability are explored in terms of the required minimum and maximum detectable signal levels and background noise in the operating environment and signal conditioning equipment. Performance limitations of fiber-optic and electroacoustic sensor designs and cost tradeoffs between the sensor and signal conditioning equipment are compared.