bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of computed tomography to the acoustic imaging of sea mines at safe standoff distances
Authors: Wyber Ron , Ferguson Brian
Published: October 2013

Typical imaging sonars make use of very high frequencies and arrays with a large number of sensors to provide high angular resolution. With such arrays the spatial resolution degrades and high propagation losses occur as the sonar is moved away from the target being imaged and operational ranges are generally 5 m or less. An alternative imaging technique has been implemented using computed tomography in which the target is insonified with a broad beam from multiple aspects. The spatial resolution achievable with this method is determined only by the bandwidth of the test signal and not by the beamwidth of the sonar or the distance of the sonar from the target. Results are presented showing clear images of mines and mine-like objects in which a spatial resolution of better than 2 cm is achieved at a range of 60 m, even for low target strength mines. Features are evident in the images that are related to both the internal and external shape of the targets as well as structural waves propagating within the targets. This offers the potential to provide unambiguous classification of mines from long ranges, even in a harsh operational environment.
Broadband noise emissions produced by pulsed 1-MHz ultrasound exposures in the presence or absence of Optison, and their relationship to the hemolytic bioeffect
Authors: Brayman Andrew A. , Chen Wen S. , Matula Thomas J. , Crum Lawrence A.
Published: October 2013

Gas-based contrast agents are known to increase ultrasound-induced bioeffects, presumably via an inertial cavitation (IC) mechanism. The relationship between IC ‘‘dose’’ (ICD) (cumulated rms broadband noise amplitude in the frequency domain) and 1.1-MHz ultrasound-induced hemolysis in whole human blood was explored with additions of Optison or degassed saline; the hypothesis was that hemolysis would correlate with ICD. Four experimental series were conducted, with variable: (1) peak negative acoustic pressure [P−]; (2) Optison concentration; (3) pulse duration; and (4) total exposure duration and variable Optison concentration. The P– thresholds for hemolysis and ICD above noise levels were ∼0.5 MPa. Enhancement of ICD and hemolysis was detected even at the lowest Optison concentration tested (0.1%) at P−=3 MPa. At 2 MPa P–(0.3% Optison), significant hemolysis and ICD were detected with pulse durations as brief as 2 and 4 cycles, respectively. At 3 MPa P–, hemolysis and ICD evolved as functions of time and Optison concentration; ultimate levels of hemolysis and ICD depended strongly on initial Optison concentration, but initial rates of change did not. Within experimental series, hemolysis was significantly correlated with ICD; across series, the correlation was significant at p less than 0.001.
Discrimination of approaching and receding sounds using three auditory motion cues
Authors: Ericson Mark
Published: October 2013

The ability to determine whether a simulated moving sound source was approaching or receding was measured in several experiments using a 2 alternative, forced-choice task. Three auditory motion cues of intensity changes, Doppler frequency shifts and inter-aural time delays were encoded onto puretone stimuli and presented over headphones. Six subjects were instructed to discriminate simulated approaching versus receding sounds. The cues were presented for several velocities, durations and simulated motion paths parallel to the median-saggital and frontal planes. As found in previous studies (Ryffert et al., 1979; Altman, 1999), approaching sounds encoded with monaural cues of frequency and intensity changes congruent with the frontal and median-saggital planes were detected at slower velocities than receding sounds. Subjects were more sensitive to ITD changes for paths parallel to the median-saggital plane than those parallel to the frontal plane (Mills, 1958; Hartman and Rakerd, 1985; Jenison and Wightman, 1995). Approaching versus receding discrimination thresholds were lower with the combined cues than with the three cues separated. The subjects were able to combine the monaural frequency and intensity changes and binaural inter-aural time delays to improve their judgments of approaching and receding sounds.
Signal–masker similarity and perceptual segregation in informational masking: Some examples
Authors: Mason Christine R. , Kidd Gerald , Durlach Nathaniel I. , Arbogast Tanya L. , Shinn-Cunningham Barbara , Colburn H. Steven
Published: October 2013

In a companion paper at this meeting (Durlach et al.) it was suggested that changes in similarity and/or perceptual segregation of a signal and masker could affect the amount of informational masking in ways that would not be predicted based on the amount of uncertainty. In that paper, several simple stimulus manipulations are used as illustrative examples of the predicted changes. Although these were suggested as gedanken (thought) experiments, data are presented here confirming these suggestions. Perceptual segregation of the signal was accomplished by varying the degree of similarity or coherence between signal and masker along a relevant stimulus dimension. For example, when the masker consisted of a set of randomly drawn upward glides, listeners perceptually segregated a downward gliding signal. This reduced the amount of informational masking obtained relative to the condition in which both signal and masker were similar upward glides. The same was true for asynchrony of onsets, difference in perceived interaural location, and variation/coherence in spectrotemporal pattern. The purpose of these experiments was to provide data that will be useful in the development of a general theory of informational masking and multisource listening that takes into account perceptual grouping/segregation and perceived similarity. [Work supported by NIH/NIDCD.]
Sensitivity to changes in amplitude envelope
Authors: Gallun Erick , Hafter Ervin R. , Bonnel Anne-Marie
Published: October 2013

Detection of a brief increment in a tonal pedestal is less well predicted by energy-detection (e.g., Macmillan, 1973; Bonnel and Hafter, 1997) than by sensitivity to changes in the stimulus envelope. As this implies a mechanism similar to an envelope extractor (Viemeister, 1979), sinusoidal amplitude modulation was used to mask a single ramped increment (10, 45, or 70 ms) added to a 1000-ms pedestal with carrier frequency (cf)=477 Hz. As in informational masking (Neff, 1994) and ‘‘modulation-detection interference’’ (Yost and Sheft, 1989), interference occurred with masker cfs of 477 and 2013 Hz. While slight masking was found with modulation frequencies (mfs) from 16 to 96 Hz, masking grew inversely with still lower mfs, being greatest for mf=4 Hz. This division is reminiscent of that said to separate sensations of ‘‘roughness’’ and ‘‘beats,’’ respectively (Terhardt, 1974), with the latter also being related to durations associated with auditory groupings in music and speech. Importantly, this result held for all of the signal durations and onset–offset ramps tested, suggesting that an increment on a pedestal is treated as a single auditory object whose detection is most difficult in the presence of other objects (in this case, ‘‘beats’’).
Informational masking without maskers
Authors: Lutfi Robert A. , Alexander Joshua M.
Published: October 2013

Informational masking is often interpreted as a failure of listeners to ‘‘perceptually segregate’’ the signal from the masker based on their different spectral-temporal properties. Though popular, such interpretations are difficult to test, as they make few specific predictions. There is, however, one prediction clearly implied by perceptual segregation. It is that informational masking should be eliminated on trials in which the masker is absent. Without a masker there can be no failure of perceptual segregation and so no masking. We report results inconsistent with this prediction. On masker-absent trials randomly interleaved with masker-present trials we show elevations in signal threshold in excess of 20 dB for some listeners. These results imply a process of perceptual summation rather than segregation. In particular, they are predicted by a model in which the decision variable is a weighted sum of signal and masker levels on each trial [Lutfi, J. Acoust. Soc. Am. 94, 748–758 (1993)]. Elevations in signal threshold on masker-absent trials are possible according to this model because the weighted sum of levels is similar on signal-alone and masker-alone trials [Work supported by NIDCD.]
A system for improving the communication of emotion in music performance by feedback learning
Authors: Schoonderwaldt Erwin , Friberg Anders , Bresin Roberto , Juslin Patrik
Published: October 2013

Expressivity is one of the most important aspects of music performance. However, in music education, expressivity is often overlooked in favor of technical abilities. This could possibly depend on the difficulty in describing expressivity, which makes it problematic to provide the student with specific feedback. The aim of this project is to develop a computer program, which will improve the students’ ability in communicating emotion in music performance. The expressive intention of a performer can be coded in terms of performance parameters (cues), such as tempo, sound level, timbre, and articulation. Listeners’ judgments can be analyzed in the same terms. An algorithm was developed for automatic cue extraction from audio signals. Using note onset–offset detection, the algorithm yields values of sound level, articulation, IOI, and onset velocity for each note. In previous research, Juslin has developed a method for quantitative evaluation of performer–listener communication. This framework forms the basis of the present program. Multiple regression analysis on performances of the same musical fragment, played with different intentions, determines the relative importance of each cue and the consistency of cue utilization. Comparison with built-in listener models, simulating perceived expression using a regression equation, provides detailed feedback regarding the performers’ cue utilization.
Dynamic stability of a beam excited by moving masses
Authors: Mackertich Seroj
Published: October 2013

The dynamic stability of an elastically supported Timoshenko beam excited by constant-velocity equally spaced traveling masses has been investigated.The regions of dynamic stability are determined for different values of the elastic foundation stiffness. Floquet theory is utilized to study the parametric regions of stability and instability, which are displayed in graphical form. Since the occurrence of this dynamic instability reduces the axial buckling load of the beam, the result is important for the study of buckling of a continuous beam.
Optimizing attenuation of sound radiation from a plate with passively shunted nonlinear piezoceramic patches
Authors: Ozer M. Bulent , Royston Thomas J.
Published: October 2013

Passive control of multi-mode sound radiation from a simply supported plate using shunted piezoceramic PZT patches is investigated. Two methods are introduced and compared for calculation of the optimal inductance and resistance values of the shunt circuits: (1) the first based on adapting Den Hartogs damped vibration absorber principle, and (2) the second based on the Shermann–Morrison matrix inversion method. Both linear and nonlinear system responses are considered. At higher disturbance levels, hysteretic nonlinearity in PZT devices may degrade the passive damping performance. The modeling of this nonlinearity using an Ishlinskii hysteresis model and the determination of the optimal shunt circuit values taking hysteresis into account is discussed. Also, in this context, two different types of piezoceramic shunt circuit configurations are considered to achieve multi-mode attenuation: (1) a single PZT patch with a multiple branched shunt circuit, and (2) multiple PZT patches with single branch shunt circuits. [Research supported by NSF Grant No. 9733565 and ONR Grant No. N00014-99-1-0342.]
Exploring the effects of gravity on tongue motion using ultrasound image sequences
Authors: Stone Maureen , Crouse Ulla , Sutton Marty
Published: October 2013

Our goal in the research was to explore the effect that gravity had on the vocal-tract system by using ultrasound data collected in the upright and supine positions. All potential subjects were given an ultrasound pretest to determine whether they could repeat a series of 3–4 words precise enough to allow an accurate series of images to be collected. Out of these potential subjects, approximately 5–7 subjects were eventually used in the research. The method of collecting ultrasound data required the immobilization of the patient by restraining their neck in a custom fitted neck restraint. The neck restraint held an ultrasound transducer positioned at a critical angle underneath the patients’ lower jawbone, which served to reduce errors and increase image resolution. To accurately analyze the series of images collected from ultrasound imaging, the surfaces of the tongue were digitized and tongue motion was time-aligned across the upright and supine sequences. Comparisons between the upright and supine data were then made by using L2 norms to determine averages and differences regarding the behavior between the two positions. Curves and locations of the maximum and minimum differences will be discussed.
Quantitative analysis of vocal fold vibration during register change by high-speed digital imaging system
Authors: Kumada Masanobu , Kobayashi Noriko , Hirose Hajime , Tayama Niro , Imagawa Hiroshi , Sakakibara Ken-Ichi , Nito Takaharu , Kakurai Shin’ichi , Kumada Chieko , Wada Mamiko , Niimi Seiji
Published: October 2013

The physiological study of prosody is indispensable in terms not only of the physiological interest but also of the evaluation and treatment for pathological cases of prosody. In free talk, the changes of vocal fold vibration are found frequently and these phenomena are very important prosodic events. To analyze quantitatively the vocal fold vibration at the register change as the model of prosodic event, our high-speed digital imaging system was used at a rate of 4500 images of 256–256 pixels per second. Four healthy Japanese adults (2 males and 2 females) were served as subjects. Tasks were sustained phonation containing register changes. Two major categories (Category A and B) were found in the ways of changing of vocal fold vibrations at the register change. In Category A, changes were very smooth in terms of the vocal fold vibration. In Category B, changes were not so smooth with some additional events at the register change, such as the anterior–posterior phase difference of the vibration, the abduction of the vocal folds, or the interruption of the phonation. The number of the subtypes for Category B is thought to increase if more subjects with a wider range of variety are analyzed. For the study of prosody, our high-speed digital imaging system is a very powerful tool by which physiological information can be obtained.
Transconsonantal coarticulatory patterns in VCV utterances: Effects of a bite block
Authors: Yunusova Yana , Weismer Gary
Published: October 2013

The concept of coordinative structures, or articulatory synergies, envisions a collection of articulators organized to achieve a specific articulatory goal or acoustic goal. The mandible figures prominently in concepts of articulatory synergies because of its potential interaction with labial and lingual shaping of the vocal tract. What happens to these hypothesized synergies when one component is taken out of the collective? Bite block articulation is a common experimental approach to eliminating the jaw from its synergistic role in articulation, and studies have shown that the speech mechanism is able to reorganize its target configurations almost immediately when speaking with a fixed jaw. In the current study we examine vowel-to-vowel, transconsonantal effects with and without a bite block. Although there is one study [Sussman, Fruchter, and Cable, J. Acoust. Soc. Am. (1995)] showing stability of coarticulatory effects in biteblock conditions, that conclusion was based primarily on locus equations. In the current study, we hypothesize that more traditional acoustic measures of right-to-left and left-to-right coarticulation will show that reducing an articulatory synergy by holding one of its components constant will result in different-from-typical coarticulatory behaviors. [Work supported by NIDCD Award No. DC 000319.]
The relation between first-graders’ reading level and vowel production variability and presentation format: A temporal analysis
Authors: Baker Kandice , Fowler Anne , Bell-Berti Fredericka
Published: October 2013

The purpose of this research is to determine if children with reading difficulties produce vowels with greater variability than children with normal reading ability. The vowels chosen for this study are /ɪ/, /ε/, and /æ/, occurring in real and nonsense monosyllabic words. Our past research, examining spectral variability in vowels produced by first grade students as a function of whether they were reading words presented individually in random or blocked format, revealed no systematic effect of presentation format on variability [K. Baker, A. Fowler, and F. Bell-Berti, J. Acoust. Soc. Am. 110, 2704 (2001)]. The purpose of this present study is to determine if good and poor readers differ in vowel duration variability. [Work supported by U.S. Dept. of Education, McNair Scholars Program.]
High speed MRI of laryngeal gestures during speech production
Authors: Nissenbaum Jon , Hillman Robert E. , Kobler James B. , Curtin Hugh D. , Halle Morris , Kirsch John E.
Published: October 2013

Dynamic sequences of magnetic resonance images (MRI) of the vocal tract were obtained with a frame rate of 144 frames/second. Changes in vertical position and length of the vocal folds, both observable in the mid-sagittal plane, have been argued to play a role in consonant production in addition to their primary function in the control of vocal fundamental frequency (F0) [W. G. Ewan and R. Krones, J. Phonet. 2, 327–335 (1974); A. Lofqvist et al., Haskins Lab. Status Report Speech Res., SR-97/98, pp. 25–40, 1989], but temporal resolution of available techniques has hindered direct imaging of these articulations. A novel data acquisition sequence was used to circumvent the imaging time imposed by standard MRI (typically 100–500 ms). Images were constructed by having subjects rhythmically repeat short utterances 256 times using the same F0 contour. Sixty-four lines of MR data were sampled during each repetition, at 7 millisecond increments, yielding partial raw data sets for 64 time points. After all repetitions were completed, one frame per time point was constructed by combining raw data from the corresponding time point during every repetition. Preliminary results indicate vocal fold shortening and lowering only during voiced consonants and in production of lower F0.
Nonlinear viscoelastic response of vocal-fold tissues
Authors: Chan Roger W
Published: October 2013

Previous rheological measurements of the viscoelastic shear properties of vocal-fold tissues have focused on the linear regime, in the small strain region typically with γ0≤1.0%. This imposed limit was necessary in order for the theory of linear viscoelasticity to be valid, yielding dynamic shear data that can be applicable for the biomechanical modeling of small-amplitude vocal-fold oscillation. Nonetheless, as the physiological range of phonation does involve more than small-amplitude oscillation, the large strain viscoelastic behaviors of vocal-fold tissues are equally important and remain to be quantified. This paper reports preliminary measurements of some of these viscoelastic behaviors in large strain shear. Excised sheep vocal-fold mucosal tissues were subject to stress relaxation, constant stress, and constant strain rate tests in a controlled-strain torsional rheometer. Results showed that vocal-fold tissues demonstrate nonlinear viscoelastic response in shear, including stress relaxation that is dependent on strain and strain creep that is dependent on stress. These findings cannot be adequately described by Y. C. Fung’s quasilinear viscoelasticity formulation, which assumes strain dependence and time dependence to be separable. A more general constitutive model is being developed to better characterize the observed nonlinear response.
Harmonics to noise ratio in vocal professional voices
Authors: Bonetti Luka , Bonetti Ana , Bolfan Stosic Natalija
Published: October 2013

There is no arguing about the importance of voice, especially in groups of vocal professional voices. The question is what characterizes, the most, normal or pathological voice in relation to aspects of human working life. Harmonics to noise ratio, according to findings from the field of voice disorders, is the most representative method to differ normal from pathological voice. In this research significant differences were found in harmonics to noise ratio in relation to the length of the working age of 29 teachers of primary schools in Zagreb. Teachers with the longest working age (40-yr.) showed the most distorted voices. The best quality of voice with great ratio of harmonics to noise was found in the group of teachers with 10 years of professional work. Acoustical analyses were made by ezvoiceplusTM version 2.0 and Gram. 2.3. Significant statistical differences were established by the T test of Statistica for Windows, version 4.5. [Work supported by Ministry of Science and Technology of Republic of Croatia.]
Tongue position and orientation for front vowels in the X-Ray Microbeam Speech Production DataBase
Authors: McGowan Richard S.
Published: October 2013

The positions and orientations of the secant lines between pellets will be examined for front vowels of four talkers in the X-Ray Microbeam Speech Production Database. The effect of vowel height and palate shape will be examined, as will the contextual effects of neighboring stop, fricative and nasal segments. This work is part of a project to describe tongue motion in terms of secant line kinematics. Preliminary results suggest that tongue blade orientation for high front vowels is determined largely by palate shape.
Isolated word recognition using dynamic synapse neural networks
Authors: Dibazar Alireza A. , Namarvar Hassan H. , Berger Theodore W.
Published: October 2013

In this paper we propose a new method for using dynamic synapse neural networks (DSNNs) to accomplish isolated word recognition. The DSNNs developed by Liaw and Berger (1996) provide explicit analytic computational frameworks for the solution of nonlinear differential equations. Our method employs quasilinearization of a nonlinear differential equation to train a DSNN. This method employs an iterative algorithm, which converges monotonically to the extremal solutions of the nonlinear differential equation. The utility of the method was explored by training a simple DSNN to perform a speech recognition task on unprocessed, noisy raw waveforms of words spoken by multiple speakers. The simulation results showed that this training method has very fast convergence with respect to other existing methods. [Work supported by ONR and DARPA.]
2D imaging of breaking waves with a pulse-coherent phased array
Authors: Smith Jerome
Published: October 2013

Breaking waves represent a serious challenge in the study of the air–sea interface. Entrainment of air and the expulsion of droplets and particles by breaking waves are of primary importance to material fluxes in particular and air/sea exchanges in general. Observations of motion near the surface is key to understanding the kinematics and dynamics of this elusive interface. Unfortunately, it is nearly impossible to obtain measurements closer than a meter or two below actively breaking wave crests in the open ocean. Here, measurements from an up-looking phased-array sonar system are presented. The system provides measurements over pies about 22 degrees wide by 16 m maximum range, with resolution 1.5 degrees by 5 cm. The instrument was 13.5 m below the mean surface, so the measurement cell size near the surface is about 5 cm (vertical) by 30 cm (along-wind). Sequences of intensity images can be analyzed for motion and relative scatterer (bubble) density. Data presented were obtained as a wave of about 2.5 m height crest to trough passed through the field of view while breaking (one of several breakers captured over a two-week deployment from R/P Flip).
Learning about waves with musical acoustics
Authors: Rossing Thomas D.
Published: October 2013

Sound waves, water waves, quantum waves, light waves, and other types of electromagnetic waves have much in common that can be understood by doing experiments in wave propagation with one or more of these types of waves. Sound waves are particularly useful because of their convenient wavelengths, and sound waves associated with music or musical instruments are attractive to students. We describe experiments in musical acoustics that have applications to other areas of physics and to engineering.
Vowel formant discrimination in quiet, speech-shaped noise, and babble for natural speech
Authors: Liu Chang , Kewley-Port Diane
Published: October 2013

Vowel formant discrimination in quiet and in noise for naturally spoken vowels was investigated. The stimuli were seven isolated vowels /i, u, I, ε, ʌ, æ, a/ recorded from a female talker and resynthesized using STRAIGHT with and without formant shifts. Vowels were presented in two noise types, long-term speech-shaped noise (LTSSN) and twelve-talker babble. ΔF was measured for F1 and F2 in quiet and noise with five signal to noise ratios (SNRs), +4, +2, 0, −2, and −4 dB. Adaptive tracking procedures were used, interleaving quiet and SNR levels for one formant at a time. Overall, results suggested that formant frequency, SNR, and noise type had significant effects on ΔF. For either LTSSN or babble, ΔF as a function of formant frequency showed four significantly different patterns, depending on the SNRs. ΔF as a function of SNR also showed several different patterns for different formants. A surprising result was that ΔFs were higher at −2 dB than those at −4 dB in babble, particularly in the F2 region. In addition, performance in babble was significantly better than that in LTSSN at comparable SNRs. These results will be examined by partial loudness models. [Work supported by NIHDCD-02229.]
Fermat’s principle and acoustic tomography in a time-dependent ocean
Authors: Godin Oleg A. , Voronovich Alexander G.
Published: October 2013

Fermat’s principle states that, for nondispersive waves propagating between two given points, travel time is stationary with respect to small variations of the wave propagation path around the actual path (i.e., ray) taken by the wave. This fundamental principle governing short wave kinematics was first established by seventeenth century French mathematician Pierre de Fermat. The principle is of particular importance for acoustic tomography because it allows one to neglect perturbations in ray geometry when performing a linear inversion of acoustic travel times for sound speed variations. Derivations of Fermat’s principle available in the literature does not apply to acoustic waves in media with time-dependent sound speed. Moreover, the very formulation of the principle in this case is not obvious as travel time along a trial ray ceases to be a single-valued functional of the trial ray geometry. In this paper, the Fermat’s principle is extended to media with time-dependent parameters. We consider acoustic waves in the inhomogeneous, moving or quiescent fluid. Formulations of the principle in terms of travel time and eikonal are compared. Applications of the established principle to ocean acoustic tomography and modeling wave propagation in weakly nonstationary, inhomogeneous ocean are discussed. [Work supported by ONR.]
Intraglottal pressures for large glottal diameters
Authors: Scherer Ronald C. , De Witt Kenneth J. , Kucinschi Bogdan R.
Published: October 2013

This study examined the glottal wall pressures for larger glottal diameters, for which the glottis can not be considered ‘‘long.’’ A Plexiglas model was used. The glottal duct length was held constant at 0.30 cm, and the ratios of glottal diameter to duct length were 0.267, 0.533, and 1.07 (diameters of 0.08, 0.16 and 0.32 cm, respectively). Fourteen pressure taps lined the vocal fold surfaces. Diameters ranged from divergent 40° to convergent 40°. Transglottal pressures ranged from 1 to 15 cm H2O. Results suggest that (1) for diffuser shapes, greater diameters tended to move the minimum glottal pressure upstream of the minimum diameter, and could enhance the pressure differences between the two sides of the glottis; (2) for the uniform glottis, for a diameter-length ratio of 0.533, the normal pressure decrease along the glottis did not occur, and for the ratio of 1.07, created a pressure rise (not fall) along the glottis; (3) for the 1.07 ratio for the converging glottal shapes, there were bimodal pressure profiles with pressure dips near the glottal entrance and the glottal exit. These findings are important in model building and determining the air pressure forces during phonation near maximum glottal excursion. [Work supported by NIH.]
On the use of finite element method in resonant ultrasound spectroscopy
Authors: Guo Hang , Lal Amit
Published: October 2013

The Rayleigh–Ritz method is conventionally used in Resonant Ultrasound Spectroscopy (RUS) for the determination of the elastic constants of materials. It limits the application of RUS only for samples in simple shapes. In order to use RUS to characterize the complicated MEMS structures, the Finite Element Method (FEM) in RUS has been studied in this paper. Starting from Hamiltonian’s principle, FEM is compared with the Rayleigh–Ritz method for RUS application. As numerical tests, the accuracy of FEM is checked by using an isotropic quartz cube and an anisotropic corundum rectangular parallelepiped. The results show that for isotropic samples FEM converges very fast and resolution of calculated natural frequencies can be as high as 0.4%. Then FEM is used to calculate natural frequencies and make mode analysis of a micromachined silicon nitride membrane achored on silicon substrate. Experimentally, the natural frequencies for those coupled membrane modes identified by FEM have been measured by RUS and used to determine Young’s modulus of silicon nitride, which is 197 GPa and verified by comparing with measured results from the Load-Deflection method. This illustrates that RUS combined with FEM can be used as a new tool for Non-Destructive Testing of thin films in MEMS structures.
Acoustic characteristics of porous media with tube-shape pores in water
Authors: Lee Kang Il , Roh Heui-Seol , Yoon S. W.
Published: October 2013

Acoustic characteristics of nonrigid porous media with tube-shape pores in water are experimentally investigated. Lucite and sand sediment are selected as the specimens. The porosities of specimens are controlled with the artificial pores of circular cylindrical tube-shape. The fast and slow longitudinal waves are identified in such porous media. The phase velocity, pressure transmission coefficient, and attenuation coefficient of the fast and slow waves are measured as the functions of frequency and porosity. This study may be applicable to acoustic diagnosis of ocean sediment and cancellous bone. [Work supported by BK21 Program, KRF (KRF-2000-015-DP0718), and KOSEF (KOSEF-2000-0238-100) in Korea.]
Benchmark workshop for geoacoustic inversion techniques in range dependent waveguides
Authors: Chapman Ross , Chin-Bing Stan , King David , Evans Richard
Published: October 2013

This paper summarizes the results from the ONR/SPAWAR Geoacoustic Inversion Techniques (IT) Workshop held in May 2001. The format of the workshop was a blind test to estimate unknown geoacoustic profiles by inversion of synthetic acoustic field data for vertical and horizontal array geometries in range dependent shallow water waveguides. The fields were calculated using COUPLE/RAM for three range-dependent test cases: a monotonic slope; a shelf break; and an intrusion in the sediment. Geoacoustic profiles were generated to simulate sand, silt and mud sediment environments. Different approaches for inverting the field data were presented at the workshop: model-based methods based on normal modes, parabolic equation or ray theory; perturbative methods; methods using transmission loss (TL) data; methods using vertical or horizontal array data. The geoacoustic profiles inverted by the different methods are compared using a metric based on calculation of transmission loss using the estimated profiles for geometries and source frequencies that were not used in the inversion. The results demonstrate the effectiveness of present day inversion techniques, and indicate the limits of their capabilities in range dependent environments. [Work supported by ONR.]
Flow separation in a forced oscillation glottal model
Authors: Alipour Fariborz , Scherer Ronald C.
Published: October 2013

Flow separation was investigated in pulsatile flow within a computational fluid dynamics (CFD) model of glottis motion. Two-dimensional time-dependent laminar flow was calculated for given dynamic wall geometries and flow boundary conditions. A Lagrangian–Eulerian method with a multiblock mesh was employed to allow grid points to move in space to conform to the boundaries. The glottal wall was approximated with two sinusoidal curves (one for the glottal entrance and one for glottal exit) connected with a straight line. The entrance and exit glottal diameters were changed as a sinusoidal function of time with a phase difference to generate the desired glottal wall movements. Results will be reported on the mean velocity and pressure distributions for various phase angles, frequencies, oscillation amplitudes, and Reynolds numbers. The locations of the flow separation points were obtained through a shear stress analysis using MATLAB. An increase in the glottal amplitude causes the separation points to move upstream. The study provides a better understanding of the effect of inferior–superior phase differences on the glottal flow. [Work supported by NIDCD Grant No. 1 R01 DC03566.]
Acoustic streaming generated by standing waves in narrow channels
Authors: Hamilton Mark F. , Ilinskii Yurii A. , Zabolotskaya Evgenia A.
Published: October 2013

Considerable attention has been devoted to acoustic streaming following the initial investigation by Rayleigh. A standing wave in a channel generates acoustic streaming in the form of inner and outer vortices that circulate in opposite directions. The outer vortex is the streaming pattern described by Rayleigh. The inner vortex is generated within the viscous boundary layer and has comparable thickness. Because boundary layer thickness is typically an exceedingly small fraction of channel width, the inner vortex is normally disregarded in relation to the Rayleigh streaming. However, channel widths in stacks used in thermoacoustic engines are comparable to boundary layer thickness. As channel width decreases, the relative thickness, of the inner vortex increases as that of the outer vortex decreases, and when channel width is comparable to the boundary layer thickness, the inner vortex dominates the flow field. Previous studies of inner streaming vortices have focused mainly on the problem of a cylinder oscillating in an infinite fluid. Acoustic streaming in narrow channels is studied here analytically and numerically. An analytical solution is derived in the quadratic approximation. Fully nonlinear numerical results are obtained from a 2-D code recently developed for thermoacoustic engines. Analytical and numerical results are in good agreement. [Work supported by ONR.]
The influences of phonotactic constraints of words on speech production
Authors: Ward Patricia , Charles-Luce Jan
Published: October 2013

It is known that words are stored in the mental lexicon with certain lexical and phonological properties and that these properties have consequences for the perception and production of words. Phonotactic probability is a phonological property of words. It is defined by segment position frequency and bi-phone co-occurrence frequency. A word can have a high probability pattern or a low probability pattern. In this study, the effects of the phonotactic probabilities of words on speech production have been examined in children with typical speech and language skills and children with phonological disorders. Typical children between the ages of 4–6, 7–8, and 9–11, children with phonological disorders, ages 4–11, and typical adults were studied. Twelve CVC words and nonwords, six high probability and six low probability, were used as stimuli. Each subject produced the stimulus items for audio-recording and later waveform analysis. Acoustic measurements, specifically duration, differed based upon the phonotactic probability of the stimulus item. Differences in the acoustic measurements of these productions by children of varying ages and language abilities reflect the influences of phonological and lexical variables of words stored in the mental lexicon. Results will be discussed with respect to developmental implications and cognitive skills.
Relationships between acoustic and perceptual measures of stress in nonwords produced by children with developmental apraxia of speech and children with phonological disorders
Authors: Munson Benjamin , Bjorum Elissa , Windsor Jennifer
Published: October 2013

This study investigated relationships between acoustic measures of stress in nonwords produced by children with suspected developmental apraxia of speech (sDAS) and children with phonological disorders (PD), and perceptual judgments made by trained listeners. Five children with sDAS and five children with PD produced multiple tokens of eight disyllabic nonwords with iambic and trochaic stress patterns. Measures of vowel duration, f0, and intensity were made. Children from both groups produced acoustic differences between stressed and stressless syllables. In a perception experiment, 10 listeners judged whether tokens were produced with stress on the initial or final syllable. Listeners judged that children with sDAS accurately matched target stress contours less often than children with PD. The proportion of listeners judging that a word was produced with final syllable stress was used as the dependant variable in a regression, in which the ratio of vowel duration, f0, and intensity between the two syllables served as the independent variables. All three variables predicted a significant proportion of variance in listener judgments, although the overall proportion of variance accounted for was low (R2=0.212). Thus, children with sDAS are able to produce contrasts between stressed and stressless syllables, but these are often imperceptible to listeners.
The spectra of energy scattered by dispersed anchovies
Authors: Diachok Orest
Published: October 2013

The spectra of backscattered energy by dispersed anchovies, which were reported by Holliday (1972), reveal several peaks at frequencies that correspond to theoretically calculated resonance frequencies of year classes of anchovies. Theoretical calculations are based on concurrent measurements of distributions of swim bladder dimensions and a modified form of Minnaert’s equation. Differences between calculated and measured values of the mean lengths of the second, third, and fourth year classes are within experimental uncertainties (8%). The calculated mean lengths of juvenile anchovies are in good agreement with historical measurements of this parameter. Matching of calculations and measurements of backscattered energy level versus frequency yields estimates of the total Q of spectral lines and the relative number density per year class. The resultant estimate of Q of adult anchovies is approximately 4.4. This value of Q is consistent with laboratory measurements of the Q of individual anchovies (∼7 at 15 m) and measurements of length and depth distributions of year classes. Resultant estimates of relative number densities of year-classes were consistent with historical measurements of this parameter in the Southern California Bight. [Work supported by ONR.]
Optimal acoustical design of commercial meeting and teleconference rooms
Authors: Campanella Angelo
Published: October 2013

Along with a quiet NC-25 environment, speech communication among multiple individuals in a conference room, especially for teleconferencing, should be enhanced. Conferees are often located around a table and along the room perimeter. Speech propagation among all is enhanced by a flat ceiling reflector placed as low as practical over the table and the seated participants. This reinforces direct sound with a first-bounce reflection between all parties and microphones. Ceiling perimeter, 50%–75% of the ceiling area, is absorptive. This arrangement works for a speaker-phone and for microphones placed on the ceiling reflector avoiding paper shuffling noise. In the latter case, loudspeakers are placed on the absorbing perimeter acoustical tile. Absorption must be placed on the sidewalls to avoid flutter echoes. Uneven absorber distribution among surfaces is evaluated with the Fitzroy reverberation time [D. Fitzroy, J. Acoust. Soc. Am. 31, 893–897 (1959)]. It was found that this RT at 500 Hz should be [1+log(V)]/10 (about 1/2 s) to avoid a ‘‘hollow’’ timbre in purveyed speech. Examples of good and troublesome teleconference rooms are discussed.
Hot topics in engineering acoustics
Authors: Thompson Stephen C.
Published: October 2013

From the ASA Handbook, the technical committee on Engineering Acoustics is ‘‘concerned with the evolution and improvement of acoustical techniques and apparatus, and with the promotion of new applications of acoustics for useful purposes.’’ The interest of acousticians in apparatus and techniques is at least as old as the society, as can be verified by a quick scan of the first volume of the journal. Active development continues in areas that include new materials for high power sonar devices, new structures for hearing aid transducers, the announcement of the first commercial micromachined silicon microphone, multimedia and 3-D audio applications, and more. This paper is an abbreviated report on a few of these developments.
Modeling sound transmission and reflection in the pulmonary system and chest with application to diagnosis of a collapsed lung
Authors: Royston Thomas J. , Zhang Xiangling , Mansy Hussein A. , Sandler Richard H.
Published: October 2013

Experimental studies have shown that a pneumothorax (collapsed lung) substantially alters the propagation of sound introduced at the mouth of an intubated subject and measured at the chest surface. Thus, it is hypothesized that an inexpensive diagnostic procedure could be developed for detection of a pneumothorax based on a simple acoustic test. In the present study, theoretical models of sound transmission through the pulmonary system and chest region are reviewed in the context of their ability to predict acoustic changes caused by a pneumothorax, as well as other pathologic conditions. Such models could aid in parametric design studies to develop acoustic means of diagnosing pneumothorax and other lung pathologies. Extensions of previously developed simple models of the authors are presented that are in more quantitative agreement with experimental results and that simulate both transmission from the bronchial airways to the chest wall, as well as reflection in the bronchial airways. [Research supported by NIH NCRR Grant No. 14250 and NIH NHLBI Grant No. 61108.]
Minor-loss coefficients for the exit from heat exchangers in thermoacoustics
Authors: Wakeland Ray Scott , Keolian Robert M.
Published: October 2013

Heat exchanger minor losses in thermoacoustics are sometimes estimated using ΔĖ=−(4/3π)(ρmA/2)K|uA|3, where ρm, uA, and A are the gas density, peak velocity amplitude, and cross-sectional area, and K is a ‘‘minor loss coefficient’’ [G. W. Swift and D. C. Ward, J. Thermophys. Heat Transfer 10, 652–662 (1996)]. Because values for K are generally unavailable for oscillating flow, steady-flow results are used, including the formula Ke=(1−A1/A2)2 for sudden increase from cross-sectional area A1 to a larger area A2, such as at the exit from a heat exchanger. This steady-flow result assumes a uniform cross-sectional velocity profile. In this presentation, non-uniform, time-dependent velocity profiles for laminar oscillating flow are employed to calculate effective minor-loss exit coefficients, which might represent an improvement over the steady-flow formula for calculating flow losses at the exit from heat exchangers in thermoacoustic devices. Differences from the uniform flow calculation can be significant. For example, for A1/A2=0.66, a reasonable value for a heat exchanger, this calculation of minor loss is as much as 3.4 times greater than the uniform profile result. [Work supported by ONR and the Pennsylvania Space Grant Consortium.]
Stellar Spin-Orbit Misalignment in a Multiplanet System
Authors: Huber Daniel , Carter Joshua A. , Barbieri Mauro , Miglio Andrea , Deck Katherine M. , Fabrycky Daniel C. , Montet Benjamin T. , Buchhave Lars A. , Chaplin William J. , Hekker Saskia , Montalbán Josefina , Sanchis-Ojeda Roberto , Basu Sarbani , Bedding Timothy R. , Campante Tiago L. , Christensen-Dalsgaard Jørgen , Elsworth Yvonne P. , Stello Dennis , Arentoft Torben , Ford Eric B. , Gilliland Ronald L. , Handberg Rasmus , Howard Andrew W. , Isaacson Howard , Johnson John Asher , Karoff Christoffer , Kawaler Steven D. , Kjeldsen Hans , Latham David W. , Lund Mikkel N. , Lundkvist Mia , Marcy Geoffrey W. , Metcalfe Travis S. , Silva Aguirre Victor , Winn Joshua N.
Published: October 2013

Misaligned Planets

Stars with multiple coplanar planets have not been seen to show misalignments between the equatorial plane of the star and the orbital plane of the planets—a diagnostic of the dynamical history of planetary systems.Huberet al.(p.331) analyzed the Kepler 56 planetary system, which contains a giant-sized and an intermediate-sized planet. The planets have orbits that are close to coplanar, but the planetary orbits are misaligned with the stellar equator. A third companion in a wide orbit, which could be another star or a planet, could explain the misaligned configuration.
Path to Treat Rett Syndrome
Authors: Percy Alan K.
Published: October 2013

Rigorous testing of potential disease-modifying factors of Rett syndrome is needed to guide research findings toward clinical trials.
South Korea's Charge Into Basic Research Meets Resistance
Authors: Stone Richard
Published: October 2013

Backers say that South Korea's fledgling Institute for Basic Science will lead the country to a new economic model built on homegrown innovations. Critics blast the institute as a "black hole" that will suck resources from existing grant programs.
Evaluation of a Multitarget Real-Time PCR Assay for Detection of Bordetella Species during a Pertussis Outbreak in New Hampshire in 2011
Authors: Gao Fengxiang , Mahoney Jennifer C. , Daly Elizabeth R. , Lamothe Wendy , Tullo Daniel , Bean Christine
Published: October 2013

A multitarget real-time PCR assay with three targets, including insertion sequence
481
(IS
481
), IS
1001
, and an IS
1001
-like element, as well as pertussis toxin subunit S1 (
ptxS1
), for the detection of
Bordetella
species was evaluated during a pertussis outbreak. The sensitivity and specificity were 77 and 88% (PCR) and 66 and 100% (culture), respectively. All patients with an IS

481 C
T

of <30 also tested positive by
ptxS1
assay and were clinical pertussis cases. No patients with IS

481 C
T

values of ≥40 tested positive by culture. Therefore, we recommend that culture be performed only for specimens with IS

481 C
T

values of 30 ≤

C
T

<40.