bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic response of a bounded, three-dimensional, viscoelastic body
Authors: Felszeghy Stephen F. , Sackman Jerome L. , Goldsmith Werner 
Published: October 2005

The isothermal response of a bounded, three-dimensional viscoelastic body, subject to arbitrary body forces, initial conditions, and boundary conditions, is considered within the linear theory of viscoelasticity. The viscoelastic properties of the body are assumed to be isotropic and homogeneous. The boundary surface areas over which the boundary conditions are specified are assumed to remain constant with time. The response is first found formally in terms of a causal Green’s function. It is then shown that when Poisson’s ratio is constant, the causal Green’s function can be expanded in a series of spatial eigenfunctions of an associated elastic eigenvalue problem. The resulting solution for the general problem is an eigenfunction series with Laplace transformed time-dependent coefficients. The solution is inverted for two special cases, when the body forces and boundary conditions are separable in space and time, and when the relaxation function in simple shear has the form of a series of decaying exponentials.
Subject Classification: [43]40.20; [43]35.50.
Large wavelength pulse propagation in curved elastic rods
Authors: Moodie T. Bryant , Rogers C. , Clements D. L. 
Published: October 2005

Longitudinal pulse propagation in slightly curved elastic rods is discussed in terms of an elementary theory due to Hsieh and Lee for which rotary inertia and radial shear are neglected. Moreover, the wavelength of motion is sufficiently long for practically all bending effects to be neglected. Three different approaches are presented. In the first, reduction of the Fourier transform of the governing equation to Bessel’s equation is sought. In the second, generalized Baecklund-type transformations are utilized to reduce the characterizing equation to the conventional wave equation for certain radius of curvature variations. Finally, the formal Karal–Keller technique is used to solve certain impact problems. Numerical results are presented in graphical form.
Subject Classification: [43]40.22; [43]20.15, [43]20.20, [43]20.45.
Diffuse sound fields: Eigenmode and free-wave models
Authors: Waterhouse R. V. , Cook R. K. 
Published: October 2005

The diffuse sound field as used in standard measurements in reverberant enclosures has been analyzed in terms of two different models, the eigenmode and the free-wave models. Recently the question has been raised as to the extent to which these models are consistent. To investigate these matters, the energy density as a function of position is calculated for axial, tangential, and oblique modes in a rectangular enclosure. The results show that, for a sound field consisting of several overlapping oblique modes, excited by a narrow band of noise, increases of mean sound pressure levels at the walls, edges, and corners of the enclosure are predicted that are in agreement with the results of the free-wave analysis and experiment. It is concluded that the two models are consistent. The inplications of the models, regarding the spatial uniformity of energy, are discussed.
Subject Classification: [43]55.20; [43]20.30.
Analysis of binaural detection models for dependence on interaural target parameters
Authors: Domnitz R. H. , Colburn H. S. 
Published: October 2005

It is shown that any binaural detection model in either of two broad classes will, subject to certain approximations, correctly predict relative detection performance for tones masked by noise as a function of interaural tone parameters. A corollary of this result is that any model in either class gains little support by fitting this body of detection data. More meaningful support for any of these models is most likely to come from the adequacy of its predictions for performance as a function of other parameters, such as target frequency, interaural masker parameters, and masker spectrum. It appears that all binaural detection models in the literature are closely related to one of the two classes defined in this paper.
Subject Classification: [43]65.62, [43]65.58, [43]65.35.
Sonar target discrimination by instrumented human divers
Authors: Fish J. F. , Johnson C. S. , Ljungblad D. K. 
Published: October 2005

A series of sonar discrimination experiments has been performed using instrumented human divers wearing a helmet with a sending and two receiving transducers. Porpoiselike broad-band clicks, with energy centered about 60 kHz, were projected and the returning echoes stretched electronically in time by a factor of 128 to enable the divers to hear them. Data were collected using metallic plate targets and targets of different geometrical shapes that were previously used in experiments with a porpoise. A comparison of scores indicated that the instrumented divers performed as well as, and in some cases better than, the porpoise.
Subject Classification: [43]65.62; [43]30.82.
Some preliminary observations on the interrelations between two-tone suppression and combination-tone driving in the anteroventral cochlear nucleus of the cat
Authors: Greenwood D. D. , Merzenich M. M. , Roth G. L. 
Published: October 2005

For units of the anteroventral cochlear nucleus in the cat—as for primary units—response to a best-frequency tone f1 can be markedly reduced when a higher-frequency suppressing tone f2 of equal or greater intensity is presented simultaneously at a frequency separation corresponding, in the present experiments, to an optimal distance on the basilar membrane of about 0.5–0.8 mm. More data are needed, but this distance does not seem to vary systematically with best frequency and may be related to critical bandwidth. In further preliminary experiments, we have compared unit response to the combination tone, 2f2−f3, formed when f1 is omitted and f3 is added above f2, with the unit’s response to a three-tone stimulus. The three-primary stimulus consists of tones with equispaced frequencies and controllable phase and amplitude relations. Primary tone f1 and combination tone 2f2−f3 coincide at best frequency, while f2 and f3 lie above the tuning curve. The comparison of response to 2f2−f3 ’’alone’’ and of response to the resultant of f1 and 2f2−f3, while f1 phase is varied, allow relative amplitudes to be calculated. They are such that f1 appears suppressed in amplitude by f2 and f3, while 2f2−f3 is correspondingly less than cancellation-tone estimates. For constant f2 level, 2f2−f3 amplitude reaches maximum when f3 amplitude almost equals f2 and decreases markedly as f3 amplitude exceeds f2. Lastly, when the combination tone resultant composed of 2f1−f2 and 3f2−2f3 lies at best frequency, variation in the phase of f1 produces a marked variation in rate of response to the resultant, appearing to parallel psychophysical results obtained by J. L. Goldstein [’’Aural combination tones,’’ in Frequency Analysis and Periodicity Detection in Hearing, edited by R. Plomp and G. F. Smoorenburg (Sijthoff, Leiden, Netherlands, 1969/1970)].
Subject Classification: [43]65.56, [43]65.42, [43]65.75.
Ballistic range experiments on superbooms generated by refraction
Authors: Sanai M. , Toong T.-Y. , Pierce A. D. 
Published: October 2005

Experiments are reported which pertain to the phenomenon of enhanced sonic booms or superbooms generated as a result of atmospheric refraction in threshold-Mach-number flights. Such ’’refraction superbooms’’ are created in a ballistic range by firing projectiles at low supersonic speeds into stratified medium of varying sound speed consisting of an inhomogeneous mixture of CO2 and air. The pressure signature recorded by a fast-response transducer inserted in the flow field is studied in conjunction with sets of dual-schlieren pictures obtained simultaneously during each run. The flow field observations indicate that the generated shocks are reflected near the sonic cutoff elevation, where the local sound speed equals the projectile speed, provided that such an elevation exists. The incident shock and its reflected portion join to form a Y-shaped configuration near the cutoff region. Enhanced shock overpressures are detected near the ’’critical altitude’’ where the flow speed behind the shock becomes sonic. A maximum focus factor of 1.7 has been measured for the leading shock which, with some theoretical assumptions, leads to an estimated value of 1.3 for the constant which appears in the Guiraud–Thery scaling law. The same value is also deduced from field data taken during aircraft threshold Mach-number flight by Haglund and Kane. The substantial agreement between the two experimentally derived values of the constant and the theoretical estimate of 1.4 given by Thery, Lecomte, and Reggiani seems to suggest the validity of the above-mentioned scaling law. However, the discrepancy of these numbers with the value of 2.6 derived by Gill and Seebass indicates that further investigation is still needed.
Subject Classification: [43]25.20, [43]25.30; [43]28.55; [43]50.55.
Broadside bearing response pattern of a line array to a cylindrical wave in a random medium
Authors: Fitelson Michael M. 
Published: October 2005

In a previous paper, the author examined the bearing response pattern of a line array to a plane wave in a random medium. It was found that random effects are strongest when the source is broadside to the array. In this paper, the corresponding situation for a cylindrical wave is examined. A comparison is made with the plane-wave case.
Subject Classification: [43]30.20, [43]30.40; [43]45.10; [43]20.15; [43]30.82.
Effects of practice on the perception of dichotically presented stop-consonant–vowel syllables
Authors: Porter Robert J. , Troendle Roger , Berlin Charles I. 
Published: October 2005

Changes in subjects’ performance on dichotic pairs of CV’s were observed over an eight-week period. Results are of practical significance in that certain performance characteristics were found to remain invariant with practice or reach an asymptotic value after 300–400 trials. The results are also of theoretical interest, however, in that unchanging patterns of response may reflect the operations of processes which are more ’’built-in’’ to the perceptual system, whereas changes in performance with practice may reflect the operation of more ’’plastic’’ processes responsible for phonetic feature decoding. Also emphasized is the importance of considering both the amount of practice and individual differences when interpreting some aspects of dichotic results.
Subject Classification: [43]70.30, [43]70.70.
Self-noise in the solion polarized cathode acoustic linear transducer (SPOCAL) and the use of the SPOCAL in seismometry
Authors: English G. Earle , Adair Robert S. 
Published: October 2005

Investigation into the self-noise of a SPOCAL (solion polarized cathode acoustic linear) transducer has identified the mechanisms responsible for this self-noise. Measurements on this transducer have shown it to have a noise threshold of 10−5 μbar, or less than 10−8 mm Hg. Therefore, the linear dynamic range of this type of transducer is 100 dB in the pressure range from 10−5 to 10+3 μbar, with a frequency range from 0.0002 to 3 Hz. The noise thresholds of conventional liquid-pressure measuring devices are several orders of magnitude higher than those of SPOCAL tranducers. The SPOCAL transducer has been applied in a seismometer where it senses the motion of a mercury column as the inertial mass. This SPOCAL seismometer obtains valid data from seismic activity at levels far below the capability of the instruments currently in use.
Subject Classification: [43]85.24, [43]85.40; [43]40.50.
An observation of culvert whistlers
Authors: Kammer D. W. , Erickson J. D. , Vorech B. A. , Walker P. M. 
Published: October 2005

Whistles of descending frequency are heard in the resulting sound after presenting a sharp pulse of noise at the entrance to a long cylinder or culvert. The underlying theory of this dispersive behavior of sound is discussed and experimental confirmation is presented.
Subject Classification: [43]20.45.
Swept edge to reduce the noise generated by turbulent flow over the edge
Authors: Filler L. 
Published: October 2005

When turbulent fluid flows over an edge, swept at an angle α to the flow direction, it is shown from simple physical arguments that the radiated sound intensity can be reduced by at least a factor of cosα. The anticipated sound reduction depends on the assumption that the normal component of turbulent momentum convected over the edge is the dominant contributor to the edge interaction noise mechanism at high Reynolds numbers. Some preliminary experimental results which confirm the noise reduction are presented for a jet flowing over an edge swept in a sawtooth configuration.
Subject Classification: [43]28.65; [43]50.55.
Speech resynthesis from phoneme-related parameters
Authors: Olive Joseph P. , Spickenagel N. 
Published: October 2005

In our recent work on speech analysis and resynthesis, we have been using predictor (LPC) derived area functions to describe the spectrum of the acoustic signal. It has been found that small changes in the value of these parameters do not affect the speech quality. If the acoustic signal is indeed overspecified by these parameters, then bit reduction is achieved by specifying the data less often, at fixed or varied intervals, or with less accuracy; however, we have chosen a scheme where less frequent sampling of the parameters is determined by the properties of the speech mechanism. We have found that if the boundaries of the steady-state portion of the phonemes are found, the steady-state portions, as well as the transitions between the phonemes, can be represented by straight lines. This method allows for the description of the acoustic signal with two sets of points per phoneme. Numerous sentences have been encoded by this method, and the resulting sentences do not sound differently from the sentences from which the data were derived. Such a scheme could be used for a rule-synthesis scheme, as well as for segmentation of speech in speech recognition schemes.
Subject Classification: [43]70.50, [43]70.40.
Biochemistry of neomycin ototoxicity
Authors: Schacht Jochen 
Published: October 2005

The biochemical mechanism of neomycin ototoxicity was investigated in vivo and in vitro. In vivo, the incorporation of [32P]–orthophosphate into the phosphoinositide lipids of inner ear tissues was measured in normal and in neomycin-treated guinea pigs. These lipids are believed to be involved in the control of membrane permeability. There was a decrease of labeling of phosphatidylinositol diphosphate in the organ of Corti and stria vascularis following three weeks of daily injections of neomycin (100 mg/kg body weight). In homogenates of organ of Corti and stria vascularis the hydrolysis of phosphatidylinositol diphosphate was blocked and the binding of radioactive calcium was inhibited in the presence of neomycin. Further in vitro studies with brain subfractions demonstrated that the effect on phosphoinositide metabolism is exerted by neomycin and related antibiotics that are toxic to the cochlea and the kidney. The hypothesis is discussed that the ototoxic action of neomycin involves an inhibition of polyphosphoinositide turnover by direct binding of the antibiotic to these lipids.
Subject Classification: [43]65.20.
Ambient noise under Antarctic sea ice
Authors: Kibblewhite A. C. , Jones D. A. 
Published: October 2005

Underwater ambient noise spectra are described for data recorded during late spring conditions under the ice sheet in McMurdo Sound. The ambient noise was at all times marked by intense biological activity, but a diurnal component became apparent during a three-day recording period. This noise was found to be similar to that described in Arctic work and undoubtedly arose as the result of surface cracking under the influence of thermal stressing. The characteristics of this noise component, however, were found to differ in certain respects from those reported from comparable Arctic measurements.
Subject Classification: [43]30.20, [43]30.70; [43]28.65.
Sound propagation through a fluctuating stratified ocean: Theory and observation
Authors: Munk W. H. , Zachariasen F. 
Published: October 2005

We have derived expressions for the mean-square phase and intensity fluctuations and their spectra for cw sound propagating through a channeled fluctuating ocean. The ’’supereikonal’’ approximation reduces to the geometric optics (eikonal) limit for short acoustic wavelengths: λ≪2πL2H/R and λ≪L2V/(R tan2ϑ), where LH and LV are horizontal and vertical correlation lengths of the fluctuations, R is range, and tanϑ is the ray slope, replacing the traditional (and much more severe) Fresnel condition λ≪2πL2/R for a homogeneous isotropic ocean. The results can be expressed in closed form for an exponentially stratified ocean model and associated ’’canonical sound channel,’’ with superimposed fluctuations from an internal wave model spectrum based on oceanographic observations. The parameters are the stratification scale B, the inertial and buoyancy frequencies ωin and n (z), the scale j* of internal wave mode numbers, and the internal wave energy per unit area. The results are in reasonable agreement with numerical experiments based on the parabolic wave equation. For the ’’singlepath’’ 4-kHz transmission over Cobb Seamount the observed and computed rms fluctuations in phase are 1.6 and 2.5 cycles, respectively; in intensity these are 5.5 and 2.2 dB, respectively, with anomalous intensities measured at high frequencies (’’sporadic’’ multipathing?). For the multipath 406-Hz MIMI transmission, we obtain 4×10−3 and 5×10−3 sec−1, respectively, for the experimentally determined and the computed rms phase rates.
Subject Classification: [43]30.20, [43]30.40; [43]20.15.
Experiments on thermoacoustic arrays with laser excitation
Authors: Muir T. G. , Culbertson C. R. , Clynch J. R. 
Published: October 2005

A recent theoretical formulation by Westervelt and Larson predicts the development of highly directive sound beams in water through the thermalization of modulated laser light. The present paper reports the experimental validation of this theory with measurements carried out in a fresh water lake. Additional theory pertinent to practical implementation is also presented and verified. The experimental apparatus includes an optically pumped laser system operating in the conventional mode at wavelengths in either the red or infrared regions of the optical spectrum. Modulation of the stochastic light burst is provided by a half-wave Pockels cell. The acoustic measurements began with an existence test which confirmed that an acoustic signal is produced by thermo-optic demodulation of laser light in the water. The sound pulse was generated in a beam with a width and source level that are in reasonable agreement with theory. Acoustic diffraction effects associated with laser beams of finite size were also examined, as were the nearfield effects of this type of array. The relation of laser technology to further work in the blue–green spectrum is analyzed.
Subject Classification: [43]20.55; [43]85.40; [43]35.65.
Pressure disturbances from a finite cylindrical source
Authors: Remillard Wilfred J. 
Published: October 2005

A description of the acoustic pressure versus time is obtained for a finite cylindrical source whose initial overpressure is constant and uniform. Small signal analysis is used and the medium is considered dissipationless. The results show a short leading condensation followed immediately by a rarefactive impulse with a long tail which ends in a second rarefactive pulse of smaller amplitude. The analytical results are amenable to numerical methods for obtaining pressure disturbances from cylindrical sources of given lengths and radii.
Subject Classifacation: [43]20.55, [43]20.15.
Analysis of trapped-energy resonators operating in overtones of coupled thickness-shear and thickness-twist
Authors: Tiersten H. F. 
Published: October 2005

The equations of three-dimensional linear piezoelectricity are applied in the analysis of trapped-energy resonators with rectangular electrodes vibrating in coupled thickness shear and thickness twist in the vicinity of the fundmantal and odd overtone thickness-shear frequencies. Closed form asymptotic expressions for the frequency wave-number dispersion relations for the fundamental and odd overtone coupled thickness-shear and thickness-twist waves near cutoff are obtained for both the electroded and unelectroded regions of the trapped-energy resonator. The influence of piezoelectric stiffening, electrode mass loading, and electrical shorting is included in the analysis. Simple approximate boundary conditions at a junction between an electroded and unelectroded region of the plate are obtained in a manner exhibiting the natural limitations inherent in the approximation. In order that these boundary conditions can be satisfied at each such junction, in the adjacent regions the wave numbers in the direction of the junction line are assumed to be the same. The boundary conditions to be satisfied at the junctions between the unelectroded corner region and the unelectroded regions adjacent to the electroded region are obtained from an extended version of the variational principle of linear piezoelectricity. These latter conditions result in the form of the solution in the corner region. One result of the foregoing analysis is the determination of a two-dimensional condition which is a generalization of Bechmann’s number in one dimension. The above-mentioned dispersion relations and edge conditions are applied in the analysis of the steady-state vibrations of a trapped-energy resonator and a lumped parameter representation of the admittance, which is valid in the vicinity of a resonance, is obtained.
Subject Classification: [43]40.24; [43]85.52, [43]85.32.
Transient response of the basilar membrane measured in squirrel monkeys using the Mössbauer effect
Authors: Robles Luis , Rhode William S. , Geisler C. Daniel 
Published: October 2005

Measurements of the transient response of the basilar membrane were conducted using the Mössbauer effect on 33 squirrel monkeys using an experimental preparation identical to that of Rhode (1971). The stimuli were acoustic clicks 150 μsec in duration repeated 100 000–400 000 times. The amplitude of the click was varied and the responses of the malleus and of the basilar membrane at a point in the basal turn were measured. The basilar membrane’s click response is oscillatory, with a period near that of the characteristic frequency. The first few response peaks behave almost linearly with stimulus intensity, while the later peaks exhibit a pronounced nonlinearity. This behavior is shown to be consistent with the nonlinearity reported using steady-state measurement methods (Rhode, 1971). The transient response observed in some of the preparations was very lightly damped; however, a wide range in the damping of the responses was found in the different animals. A progressive increase in the rate of decay of the transient response with the duration of the experiment was observed. Any damage to the cochlea also resulted in increased damping. The measured cochlear delay time of 300–390 μsec agrees with that derived from phase curves of the transfer ratio measured with steady-state methods.
Subject Classification: [43]65.26, [43]65.20.