bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive null processing—a holographic approach and experimental results
Authors: Keating P. N. , Koppelmann R. F. , Mueller R. K. , Steinberg R. F. , Zilinskas G. 
Published: October 2005

A software-oriented adaptive null-processing technique for underwater acoustic arrays has been developed and applied to experimental data obtained from a 20×20 square array. This method, which involves spatial homodyning, is holographic in nature, with important similarities to both DICANNE and a recent holographic enhancement technique. The approach is described and evaluated, compared with other methods, and results obtained from its application to experimental underwater data are presented. The technique removes the side lobes from a source image as well as the main lobe in the null direction; a striking example of this in an underwater experiment is given.
Subject Classification: [43]60.30; [43]35.65; [43]30.82.
Energy dissipation in human hand–arm exposed to random vibration
Authors: Cundiff J. S. 
Published: October 2005

The problem of correlating the incidence of Raynaud’s phenomenon with exposure to a given vibration environment is well known. It is hypothesized that energy absorbed and dissipated in the hand is energy which can change hand tissue in some manner, and thus may cause injury. Absorbed power is therefore suggested as a parameter which has potential for evaluation of individual worker susceptibility to vibration injury. The arm is represented as a foundation with finite mechanical impedance for the hand model. The hand model parameters, obtainable from experimental impedance measurements on individual subjects, are assumed to be, in general, frequency dependent. The total impedance expression for the system is generalized for the case where the hand is gripping a vibrating handle covered with a layer of viscoelastic material. An expression for absorbed power in this composite system exposed to random vibration is presented.
Subject Classification: [43]40.45.
Instructional-laboratory experiment on temperature dependence of transducer impedance
Authors: Stumpf F. B. , Kosik D. W. 
Published: October 2005

An experiment for an advanced undergraduate or graduate laboratory in acoustics is descrived. The temperature dependence of the driving-point impedance curve of a hairpin magnetostrictive-stack transducer was measured in the temperature range 25 °C down to liquid-nitrogen temperature.
Subject Classification: [43]85.20, [43]85.40; [43]10.85.
Trill threshold revisited
Authors: Shonle John I. , Horan Kathryn E. 
Published: October 2005

Miller and Heise [J. Acoust. Soc. Am. 22, 637–638 (1950)] defined and measured the trill threshold. They found that a frequency difference of about 15% was needed for two alternating tones to be perceived as such. We made similar measurements between 250 and 4000 Hz and obtained quite different results at all but the 250-Hz frequency. Our results show a frequency dependence similar to that of critical bands, with the trill threshold about one-quarter the size of the appropriate critical bands. In addition we measured the trill threshold in the case of the 1000-Hz signal at modulation rates of 2 and 8 Hz, as well as the 5-Hz rate used by Miller and Heise. There is a significant drop in the trill threshold at the 2-Hz modulation rate.
Subject Classification: [43]65.75, [43]65.54; [43]75.10.
Model for a ring transducer with inactive segments
Authors: Butler John L. 
Published: October 2005

The equation of motion and the equivalent circuit for a segmented ring transducer which incorporates inactive segments is developed. Design considerations are discussed, and it is shown that, although the motion at resonance is dependent on the inactive segments, well below resonance the motion is independent of these segments.
Subject Classification: [43]85.52; [43]30.85.
Acoustic-emission transducer and its absolute calibration
Authors: Hatano Hajime , Mori Eiji 
Published: October 2005

A new method is developed for absolute calibration of acoustic-emission transducers using a reciprocity technique in a Rayleigh-wave sound field. It is applied to practical transducers, and their sensitivity is obtained over a frequency range of 100 kHz to 1 MHz. The result is compared with frequency spectrum of an actual acoustic emission signal from a large structure detected by an identical transducer. It is shown that practical characteristics of transducers can be estimated with ease and repeatability in an acoustical environment similar to that of structures such as pressure vessel walls.
Subject Classification: [43]40.42; [43]85.40.
Transmissibility across simply supported thin plates. II. Rectangular plates with loading masses and straight ribs
Authors: Ochs J. B. , Snowdon J. C. 
Published: October 2005

The transmissibility of thin, simply supported, rectangular aluminum plates of like dimensions has been determined experimentally in the frequency range 25–3025 Hz. Comparison has been made between the results of measurements on an unloaded plate, on plates loaded centrally by concentrated masses of small and large contact area, and on plates loaded by seven different straight-rib configurations, one of which utilized X-cut ribs that stretched diagonally between opposite plate corners. The additional mass was always equal to that of the plates so that the effectiveness of the mass in reducing transmissibility could be evaluated as a function of its geometry. The experimental transmissibilities of the unloaded and centrally mass-loaded plates were in excellent agreement with theoretical prediction. At frequencies above the fundamental resonance of the plates, the greatest overall reduction in transmissibility was provided by the X-cut ribs; whereas, at the fundamental resonance itself, the greatest reduction was provided by a single central rib placed parallel to the shorter plate sides.
Subject Classification: [43]40.24, [43]40.20.
Perception of noise transmitted through barriers
Authors: Aylor Donald E. , Marks Lawrence E. 
Published: October 2005

Perceived loudness of noise transmitted through barriers was scaled by human observers outdoors. Using the method of magnitude estimation, subjects compared the relative loudness of a narrow band of noise transmitted through barriers of different solidity. When the subjects were blindfolded, and thus unable to see the barriers, loudness was judged the same under all conditions. When the barriers were visible, however, sizable differences in loudness emerged: When the barrier only partially obscured sight of the sound source, loudness was judged less than when there was no intervening barrier; but, when the barrier totally obscured sight of the source, loudness was judged greater than when the source could be seen, either in whole (no barrier) or in part. These results point out the complex nature of the psychological effect of barriers on perceived noise levels.
Subject Classification: [43]65.50, [43]65.22; [43]50.20; [43]55.75.
Effect of temperature on cochlear responses during and after exposure to noise
Authors: Drescher Dennis G. 
Published: October 2005

Anesthetized chinchillas were maintained in the quiet for 24–48 h with virtually no loss of maximum voltage or sensitivity of cochlear microphonics (CM). Changes in body temperature and cochlear temperature from 29° to 39 °C had little effect on normal CM. With presentation of steady octave-band noise with center frequency of 1 kHz at 90 dB SPL overall, CM decreased and approached an asymptote at a rate dependent on the temperature of the preparation. The rate of reduction was less at low temperatures than at high temperatures. With termination of the noise, an initial rapid recovery of CM preceded a slow recovery toward normal CM values. The slow recovery was inhibited at low temperatures, and could be enhanced by raising the temperature. These studies indicate that noise-induced reduction of CM may be linked to processes of energy metabolism and/or may involve temperature-dependent structural changes that do not affect normal cochlear response.
Subject Classification: [43]65.66, [43]65.40, [43]65.35.
Numerical investigation of nonlinear oscillations of gas bubbles in liquids
Authors: Lauterborn Werner 
Published: October 2005

Forced oscillations of a spherical gas bubble in an incompressible, viscous liquid (water) are calculated numerically. The information gathered is mainly displayed in the form of frequency response curves of the steady-state solutions showing the harmonics, subharmonics, and ultraharmonics. Bubbles oscillating ultraharmonically at frequencies below the main resonance may emit half the driving frequency. This fact gives rise to a new explanation for the occurrence of the first subharmonic in the spectrum of the cavitation noise in ultrasonic cavitation.
Subject Classification: [43]30.70, [43]30.75.
Noise of ears and microphones
Authors: Killion Mead C. 
Published: October 2005

Although it is well known that the internal noise of the human ear is less than that of many microphones, little has been published since Baerwald (1940) directly comparing the noise level of ears and microphones. When a microphone is to be used in a hearing aid, it is of interest to know how soft a sound the wearer can hear if he turns the gain up far enough. If the noise spectrum of the microphone is known, the ’’aided pure-tone threshold’’ which can be achieved with that microphone can be calculated by utilizing the extensive literature on the masking of pure tones by noise. Following French and Steinberg [J. Acoust. Soc. Am. 19, 90–119 (1947)], one can turn the tables and calculate the apparent noise spectrum of the ear considered as a microphone. Such a calculation indicates that an acute young ear has an apparent noise level equivalent to that of a microphone with an A-weighted noise level of about 20 dB SPL. Experimental verification has been obtained on a new hearing aid microphone designed to be quieter than the human ear. A brief comment on the clinical implications of these results for hearing aid evaluation is included.
Subject Classification: [43]65.50, [43]65.80; [43]85.62.
Deep scattering layer spectra in the eastern North Pacific
Authors: Johnson Richard K. 
Published: October 2005

Measurements by several investigators of the deep scattering layer are consistent with the hypothesis that the dominant scatterers are fishes with gas-filled swimbladders of 1.6- to 3.1-mm radius. The population density of these fish is estimated from the acoustic results to be between 0.5 and 15/1000 m3.
Subject Classification: [43]30.40.
Experiments on porous blades as a means of reducing fan noise
Authors: Chanaud R. C. , Kong Ning , Sitterding R. B. 
Published: October 2005

In a study of ways to reduce the sound power produced by propeller fans, the performance of various porous blades was compared with that of solid blades. It was found that a porous-bladed fan could produce flow with characteristics similar to that produced with a solid-bladed fan, with a reduction of about 5 dB in the sound at the cost of a slight reduction in static efficiency.
Subject Classification: [43]50.30, [43]50.40, [43]50.45.
Influence of mean sound speed on acoustic transmission through an internal wave
Authors: Lieberman G. A. , Jacobson M. J. , Siegmann W. L. 
Published: October 2005

A major purpose of this paper is to investigate the influence of mean sound-speed structures on sound transmission in the presence of a single-frequency internal wave. A cw signal is transmitted through a shallow ocean over a range that is small compared to the wavelength of the internal wave. A constant value of the Brunt–Vaisala frequency is assumed, and this value is taken as a parameter of the model. The total field associated with refracted/bottom-reflected rays is studied, and the effect of the internal wave on total-field phase and transmission loss is examined. Then, the maximum variation of the phase is investigated for different mean sound-speed structures and internal-wave amplitudes. This variation shows a general downward trend, as bottom sound speed increases, and an oscillatory behavior possibly due to rapid changes in the rate of change of phase with respect to mid-depth sound speed. A simple mathematical model is constructed to explain the dominant decreasing trend. Phase variation is shown to vary linearly with bottom sound speed and to be proportional to wave amplitude, range, and acoustic frequency. It is inversely proportional to ocean depth.
Subject Classification: [43]30.20, [43]30.25.
Effect of the parallel reflecting surfaces of a transducer on the resulting pulse shape
Authors: Altman Harry E. , Beyer Robert T. 
Published: October 2005

Calculations are made of the pulse shapes for sound waves reflected from a plane transducer. These show the effect of reflections from the two parallel surfaces and their relation to pulse width and transducer thickness. Illustrations are given for several representative combinations of samples and backing media, together with photographs of pulse shapes obtained experimentally.
Subject Classification: [43]35.80; [43]85.40; [43]20.30.
Auditory filter shapes derived with noise stimuli
Authors: Patterson Roy D. 
Published: October 2005

A wide-band noise having a deep notch with sharp edges was used to mask a tone. The notch was centered on the tone, and threshold was measured as the width of the notch was increased from 0.0 to 0.8 times the tone frequency (0.5, 1.0, or 2.0 kHz). The spectrum level of the noise was 40 dB SPL. If it is assumed that the auditory filter is reasonably symmetric at these intensities, then the shape of the filter centered on the tone can be estimated from the first derivative of the curve relating tone threshold to the width of the notch in the noise. The 3-dB bandwidths of the filters obtained were about 0.13 of their center frequency. In the region of the passband, the Gaussian curve provides a good approximation to the shape of the derived filters. The equivalent rectangular bandwidths of the Gaussian approximations are about 0.20 of their center frequency, which is comparable to the critical-band estimates of R. Zwicker, G. Flottorp, and S. S. Stevens [’’Critical bandwidth in loudness summation,’’ J. Acoust. Soc. Am. 29, 548–557 (1957)]. The Gaussian approximation cannot be used outside the passband, because the tails of the derived filters do not fall as fast as the Gaussian curve.
Subject Classification: [43]65.58, [43]65.35; [43]80.50.
Detectability of auditory signals presented without defined observation intervals
Authors: Watson Charles S. , Nichols Thomas L. 
Published: October 2005

Ability to detect tones in noise was measured without defined observation intervals. Latency density functions were estimated for the first response following a signal and, separately, for the first response following randomly distributed instances of background noise. Detection performance was measured by the maximum separation between the cumulative latency density functions for signal-plus-noise and for noise alone. Values of d′, estimated by this procedure, were approximately those obtained with a 2-dB weaker signal and defined observation intervals. Simulation of defined- and nondefined-interval tasks with an energy detector showed that this device performs very similarly to the human listener in both cases.
Subject Classification: [43]65.58, [43]65.75, [43]65.50, [43]65.68.
Effect of temperature on harmonic content of microphonic response from the second cochlear turn of chinchilla
Authors: Drescher Dennis G. , Gibian Gary L. 
Published: October 2005

Cochlear microphonic responses of chinchilla to tones from 20 to 110 dB SPL were examined with a fast-Fourier-transform algorithm. Distortion of microphonics recorded from the second cochlear turn (CM2) for acoustic input at 0.225 kHz was found to increase rapidly above 50 dB SPL. Like the input–output function for the complete CM2 response, the input–output functions for the harmonics saturated near 80 dB SPL. Changes in temperature of the preparation from 29° to 39 °C had minimal effect on the pattern of the harmonics examined. These results are consistent with the hypothesis that moderate changes in temperature act primarily on metabolism supporting CM generation and not on the transduction processes per se.
Subject Classification: [43]65.40, [43]65.66, [43]65.35.
Eye color and susceptibility to TTS
Authors: Hood J. D. , Poole J. P. , Freedman L. 
Published: October 2005

Controversy has arisen over the claim that melanin content of the iris as determined by eye color bears a direct relationship to susceptibility to temporary threshold shift (TTS). Further observations have now been carried out aimed at extending the range of stimulus intensities hitherto employed together with an investigation into the possible significance of differences in the methodology. The evidence which the data brings to bear in support of the reported correlation is not particularly strong at stimulus intensities of 80 dB (HTL re ISO, 1964), but becomes more persuasive at higher intensities. At 120 dB the evidence seems conclusive, with blue-eyed subjects exhibiting significantly more TTS than brown-eyed subjects. Since this relationship is evident only when the threshold determinations are carried out using continuous tones and is absent with pulsed tones, it is concluded that the underlying mechanism is predominantly auditory adaptation and not fatigue.
Subject Classification: [43]65.66.
Comments on ’’Tissue concentrations of ethacrynic acid and inhibition of enzymes and electrophysiological responses in the cochlea’’ [ J. Acoust. Soc. Am. 58, S31 (A) (1975)]
Authors: Paloheimo S. , Thalmann R. 
Published: October 2005

The purpose of this communication is to point out an error in our determination of the concentrations of 14C–ethacrynic acid in the stria vascularis.
Subject Classification: [43]65.28, [43]65.40.
Effect of silence between tones on auditory stream segregation
Authors: Dannenbring Gary L. , Bregman Albert S. 
Published: October 2005

The present study investigates the effect on auditory stream segregation of the duration of silent gaps between items of a repeating sequence of sine tone stimuli. While previous investigators had shown that gaps reduced the tendency for items to segregate, the present experiment showed that this was not the case; rather, in adjusting tone durations for stream segregation thresholds, subjects simply compensated for increased gap duration, keeping the total time (tone duration plus gap duration) constant.
Subject Classification: [43]65.75, [43]65.54, [43]65.68.
Comments on ’’Temporal interactions within a phrase and sentence context’’
Authors: Ohala John J. , Lyberg Bertil 
Published: October 2005

The interpretation given in the subject article to the incidence of negative correlations between the durations of adjacent speech segments, viz., that they show evidence of temporal compensation, is criticized. It is shown that the negative correlations are most likely due to measurement error and to the author’s normalization of the duration of his test utterances.
Subject Classification: [43]70.40, [43]70.70, [43]70.20.
Finite-amplitude losses in spherical sound waves
Authors: Merklinger Harold M. , Mellen Robert H. , Moffett Mark B. 
Published: October 2005

An approach suggested by Westervelt [3rd Int. Congr. Acoust., Stuttgart, 1959] has previously been used to predict with remarkable accuracy the excess absorption due to nonlinear effects in a plane, traveling sound wave. The same approach is applied here to spherically diverging sound waves. A number of cases of practical importance in underwater acoustics are evaluated and compared with other theoretical results.
Subject Classification: [43]25.22; [43]30.75.
Infrasound from convective storms. III. Propagation to the ionosphere
Authors: Jones R. Michael , Georges T. M. 
Published: October 2005

We model mathematically the spectral features of infrasound observed in the ionosphere and believed to be radiated by severe thunderstorms. We explain the dominant 2–5-min wave period as an effect of atmospheric filtering; shorter periods are excessively attenuated by absorption in transit to the ionosphere, and longer periods are attenuated in portions of the atmosphere where the waves are evanescent because their frequencies are below the acoustic cutoff. An observed spectral ’’fine structure’’ within the 2–5-min band is explained in terms of resonant interactions between the waves and the atmospheric temperature structure. Accurate quantitative modeling of all these details of the storm-to-ionosphere transmission coefficient requires numerical integration of the acoustic-gravity wave equation, including the effects of ground reflection, absorption, and partial reflections in the atmosphere.
Subject Classification: [43]28.30.
Relationship of Doppler ultrasonic scattered signal characteristics to flow and beam parameters
Authors: Albright Robert J. 
Published: October 2005

The specific dependence of the properties of a cw Doppler ultrasonic scattered signal, and of its autocorrelation and spectral density functions, on various scatterer flow parameters and diagnostic signal beam parameters is shown. These factors include the scatterer average velocity profile and the extent of any turbulence together with the signal beam angle and beam width.
Subject Classification: [43]30.40; [43]35.65; [43]20.15, [43]20.30.
Mechanical impedance of human headbones (forehead and mastoid portion of the temporal bone) measured under ISO/IEC conditions
Authors: Flottorp Gordon , Solberg Sigurd 
Published: October 2005

Mechanical impedances of the mastoid portion of the temporal bone and of the forehead are presented for 60 human subjects of both sexes and of ages between 9 and 71 years. Measurements were carried out using a plane circular surface of 1.75 cm2 and a static force of 5.4 N (ISO/IEC conditions). Impedance is found to vary with age and to a lesser extent with sex. Results are consistent with earlier measurements carried out under somewhat different conditions, but deviate rather substantially at most frequencies from the recommended ISO/IEC mechanical impedance for an artificial headbone. A study of the influence of variations in the mechanical headbone impedance upon bone vibrator performance by means of an analogous electrical network is reported.
Subject Classification: [43]65.64; [43]85.20.