bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-frequency attenuation in the Pacific Ocean
Authors: Mellen R. H. , Browning D. G. 
Published: October 2005

There is increasing evidence that the low-frequency sound absorption in the Pacific is less than that in the Atlantic. The origin of the excess absorption below 1 kHz has recently been identified as a boron relaxation. A compilation of available Pacific data appears to show one-half the boron absorption found in the Atlantic, which suggests significant differences in the chemical composition of the oceans.
Subject Classification: [43]30.20, [43]20.35.
Ballistic range experiments on the superboom generated at increasing flight Mach numbers
Authors: Sanai M. , Toong T.-Y. , Pierce A. D. 
Published: October 2005

Ballistic range experiments for the study of the propagation of converging shocks are described and the similarity between the observed phenomenon and that expected for superbooms created by accelerating supersonic aircraft is discussed. For weak shocks (shock Mach numbers of about 1.03), a structure resembling that of a folded shock predicted by geometrical acoustics theory is observed while for stronger shocks, a concave front with enhanced overpressure is recorded. Other results are in general accord with the basic concepts of shock propagation and in conjunction with some theoretical scaling laws indicate that the peak magnification of sonic booms due to aircraft flight acceleration in the real atmosphere should be in the range of 6 to 13.
Subject Classification: [43]25.20, [43]25.30; [43]28.55; [43]50.55.
Investigation of laryngeal control in speech by use of thyrometer
Authors: Kakita Yuki , Hiki Shizuo 
Published: October 2005

Laryngeal control in speech was studied by observing vertical laryngeal movements using the ’’thyrometer,’’ an optoelectric device. The thyrometer consists of a light source casting a narrow beam of light onto a small mirror stuck to the skin of the neck over the laryngeal cartilages and a special photocell which picks up the reflected light beam. Vertical movements of the laryngeal cartilages tilt the mirror and thus change the angle of reflection of the light beam onto the photocell which converts the change in the angle of the light into a voltage monotonically related to the original laryngeal movements. This method yields a highly sensitive recording of the vertical movements of the larynx in running speech without causing any significant impediment to normal articulation. Using this device investigations have been made of the laryngeal mechanisms employed in the production of the following: step-function changes in pitch, word accents and sentence intonation in Japanese, and the four tones of Mandarin Chinese. The correlation between vertical larynx movement and the activity of the laryngeal muscles for pitch control is discussed based on some electromyographic data and the anatomical structure of the larynx.
Subject Classification: [43]70.60, [43]70.20.
Speaker sex identification from voiced, whispered, and filtered isolated vowels
Authors: Lass Norman J. , Hughes Karen R. , Bowyer Melanie D. , Waters Lucille T. , Bourne Victoria T. 
Published: October 2005

The purpose of this investigation was to determine the relative importance of the speaker’s laryngeal fundamental frequency and vocal tract resonance characteristics in speaker sex identification tasks. Six sustained isolated vowels (/i, -, -, a, o, u/) were recorded by 20 speakers, 10 males and 10 females, in a normal and whispered manner. A total of three master tapes (voiced, whispered, and filtered) were constructed from these recordings. The filtered tape involved 255 Hz low-pass filtering of the voiced tape. The tapes were played to 15 listeners for speaker sex identification judgments and confidence ratings of their evaluations. Results of their judgments indicate that, of the 1800 identifications made for each tape (20 speakers × 6 vowels × 15 listeners), 96% were correct for the voiced tape, 91% were correct for the filtered tape, and 75% were correct for the whispered tape. Moreover, the listeners were most confident in their judgments on the voiced tape, followed by the filtered tape, and showed the least amount of confidence on the whispered tape. These findings indicate that the laryngeal fundamental frequency appears to be a more important acoustic cue in speaker sex identification tasks than the resonance characteristics of the speaker.
Subject Classification: [43]70.30.
Asymptotic behavior of the acoustic nearfield of a circular piston
Authors: Stepanishen Peter R. 
Published: October 2005

The acoustic nearfield of a circular piston is investigated using the impulse response technique. Although the harmonic field can be expressed as either a convolution integral or Fourier transform, the integrals cannot be simply evaluated. An asymptotic evaluation of the Fourier transform of the spatially dependent impulse response for the circular piston is, however, readily performed. The resulting expressions very simply illustrate the nearfield behavior of the piston. Furthermore, the expressions are shown to be in agreement with the asymptotic properties of known nearfield results and are consistent with the usual farfield expressions.
Subject Classification: [43]20.55, [43]20.15.
Tactile localization of sounds: Acuity, tracking moving sources, and selective attention
Authors: Frost B. J. , Richardson B. L. 
Published: October 2005

Most attempts to design artificial ears have concentrated on displaying frequency information to the skin of deaf subjects in the hope that they may recognize complex patterns of sounds and thus have some ’’auditory function’’ restored. The problem from a practical standpoint is that simultaneously occurring sounds that originate from different sources are difficult if not impossible to unscramble. In normal audition, auditory localization not only enables subjects to perceive the locus of origin of sounds with a high degree of accuracy, but also appears to be the most important determinant of selective auditory attention. The three experiments reported in this paper demonstrate first of all that tactile sound localization is possible with an accuracy that approaches normal audition, and secondly that subjects can track moving sound sources. Finally, an analog of selective auditory attention was found by using tactile localization. These experiments show the utility of incorporating a localization unit in future designs of artificial ears for the completely deaf.
Subject Classification: [43]65.62, [43]65.70.
Perception of the missing fundamental by cats
Authors: Heffner Henry , Whitfield I. C. 
Published: October 2005

Two cats were tested on their ability to perceive the missing fundamental through the use of an avoidance technique. The animals were trained to discriminate between rising and falling pitch sequences first with single and then with multiple tones. They were then tested by presenting them with tone triads known to produce the perception of the missing fundamental in humans. In these triads, the pitch of the frequencies composing the triad either remained the same or shifted in the direction opposite the shift of the missing fundamental. The results show that the animals’ response to these triads was not in conformity with that expected from the direction of change of the component frequencies, but could be accounted for if it were assumed that the cats were responding on the basis of the missing fundamental. A further test given one of the cats indicated that this phenomenon declined progressively as the center frequency was raised, until at 6 kHz it was apparently completely absent. A similar decline in the strength of the fundamental pitch occurs over the same range in humans. Thus, there is reason to believe that cats perceive the missing fundamental.
Subject Classification: [43]65.75, [43]65.56, [43]65.54; [43]80.50.
Effects of sea-ice ridges on sound propagation in the Arctic Ocean
Authors: Diachok O. I. 
Published: October 2005

An environmental/acoustic model of sound propagation in the Arctic Ocean, which accounts for reflection losses from ridged sea ice, has been developed. In this model sea-ice ridges are represented as infinitely long, randomly distributed, elliptical half-cylinders. Under-ice reflection losses for acoustic wavelengths either large or small compared to ridge dimensions are computed from theoretical equations as a function of average keel depth and width, number of ridges/km, and grazing angle. Numerical values of under-ice reflection loss as a function of grazing angle are then incorporated into ray-theoretical computations of transmission loss assuming a single sound- speed profile which is characteristic of the central Arctic Ocean. The validity of the concepts and approximations, the limitations of the model, and the accuracy of coincident measurements of environmental and acoustic parameters required to validate the model are discussed. To illustrate the predictions and accuracy of the model under diverse ice conditions, several comparisons of theoretical and experimental determinations of under-ice transmission loss in the central Arctic Ocean are presented. Midwater absorption loss, a complicating feature of transmission loss measurements at high frequencies, is also considered.
Subject Classification: [43]30.20, [43]30.30.
Tilted directional response patterns formed by amplitude weighting and a single 90° phase shift
Authors: Hughes W. Jack , Thompson William 
Published: October 2005

It is shown that by appropriately processing the output signals of the elements in a symmetric array, a tilted sum pattern or difference pattern can be produced without numerous delay lines or phase-shift networks. The tilted pattern is achieved by combining, in proper phase, two outputs of an array; the first output is that of a particular amplitude weighted phase-symmetric array while the second is that of a particular amplitude weighted phase-antisymmetric array. To achieve the proper phase relationship between these two outputs, one of them must be phase shifted by ±90°. Theoretical calculations and experimental results are presented for the case of a line array of nine elements that are equally spaced a half-wavelength apart; both a sum pattern and a difference pattern tilted to 30° from the normal to the line array, by this method, are shown. The variation of the side-lobe levels of these tilted patterns is examined as the ±90° phase shift is perturbed. The possibility of using this technique to continuously vary the angle of tilt is discussed.
Subject Classification: [43]20.55; [43]30.50; [43]60.30; [43]35.54.
Intensity preception. VI. Summary of recent data on deviations from Weber’s law for 1000-Hz tone pulses
Authors: Rabinowitz W. M. , Lim J. S. , Braida L. D. , Durlach N. I. 
Published: October 2005

Data from 15 modern studies are used to characterize the deviations from Weber’s law for intensity discrimination of 1000-Hz tone pulses. The results show that Weber’s law is satisfied in the region 10–40 dB SL, that resolution descreases with decreasing intensity below 10 dB SL and increases with increasing intensity above 40 dB SL, and that resolution at 90 dB SL is roughly 2.5 times better than at 40 dB SL.
Subject Classification: [43]65.50, [43]65.75.
Resiude pitch as a function of component spacing
Authors: Patterson Roy D. , Wightman Frederic L. 
Published: October 2005

In an effort to determine whether the pitch shift of the residue is strictly proportional to the frequency spacing between the stimulus components, observers were asked to match the pitch of waves with component spacings of 100, 200, 300, or 400 Hz. The stimuli were sets of 6 or 12 equal-amplitude sinusoids and the position of each set was varied throughout the frequency range in which the resiude was audible. The pitch shift of the residue showed a disproportionate increase with component spacing for stimuli containing low-frequency components. Six-component waves produced slightly larger pitch shifts than 12-component waves, again when low-frequency components were included. As the spectral location of the set increased, both effects decreased; once the lowest component in the stimulus was more than about five times the component spacing, both effects were minimal. The results indicate that the dominance region is a function of the absolute, as well as the relative, frequency of the components in this case.
Subject Classification: [43]65.54, [43]65.35, [43]65.75.
Effects of ultrasound on unicellular algae
Authors: Giordano R. , Leuzzi U. , Wanderlingh F. 
Published: October 2005

The effect of ultrasonic irradiation (up to 3W/cm2 and 1 MHz of frequency) on unicellular algae is experimentally studied. It is unambiguously shown that the damage of the cells and their breakage is to be related to cavitation. The dynamics of the breakage is examined from the point of view of practical application.
Subject Classification: [43]80.40; [43]35.75.
Observations of the effects of atmospheric turbulence on low- frequency sound propagation
Authors: Chessell C. I. 
Published: October 2005

The propagation of low-frequency acoustic waves in the lower atmosphere is studied using observations of explosive sound sources at ranges of 4.3 and 9.3 km. By observing groups of 30 firings spaced closely in time, the effects of atmospheric turbulence on the propagation are determined; the differences in arrival time between microphone pairs in an approximately 1-km array being the experimental parameter measured. The time difference distributions are found to be Gaussian with standard deviations which show a strong diurnal variation, the increased effect of atmospheric turbulence being evident in mid-day observations. Propagation over nearby paths is shown to be spatially correlated out to separations of several hundred meters and this correlation is shown to be in agreement with the theoretical predictions of Chernov [Wave Propagation in a Random Medium, L. A. Chernov (McGraw–Hill, New York, 1960)]. Using these theoretical relations, atmospheric scale sizes in the range from 200 to 500 m (mean 320 m) are obtained together with acoustic velocity fluctuations with standard deviations in the range from 0.5 to 1.2 m/sec (mean 0.8 m/sec).
Subject Classification: [43]28.40, [43]28.60.
Study of wave motions in fluid-saturated porous rocks
Authors: Yew C. H. , Jogi P. N. 
Published: October 2005

In this investigation, Biot’s theory was employed in the study of wave motions in fluid-saturated porous rocks. Consistent with the described experimental arrangement, Biot’s equations were solved using a Laplace transformation. The theory predicts two dilatational waves: a slightly dispersed fast wave propagating ahead of a heavily dispersed and attenuated slow wave. By comparing these results with experimental results, it becomes evident that the measured waves are in fact the fast waves.
Subject Classification: [43]20.15, [43]20.40.
Measurement from the optical nearfield of an ultrasonically produced phase grating
Authors: Cook Bill D. 
Published: October 2005

A simplified expression is derived for the optical irradiance in the nearfield of a sinusoidal phase grating. Application of this expression to an ultrasonically produced optical phase grating permits the interpretation of experimental data for the magnitude of retardation and relative position of the grating. From these parameters, it is possible to evaluate the acoustic pressure distribution, total acoustic power, and sound velocity of a progressive ultrasonic beam.
Subject Classification: [43]35.65.
Relationship between acoustic reflection and vibrational modes of elastic spheres
Authors: Vogt Richard H. , Neubauer Werner G. 
Published: October 2005

The behavior of the solution to acoustic backscattering by elastic spheres in water expressed as a form function vs ka, relative to the normal modes of vibration of solid homogeneous elastic spheres is examined. Specific free modes of vibration are identified with significant changes in form function. The solution for spheres of tungsten carbide, aluminum, and brass are considered for values of ka as high as 28. Minima in the form function usually occur at or near frequencies at which sphere resonances occur. Form functions are examined which are computed from mixing rigid and elastic terms in the waveharmonic series. In this way it is possible to see the effect of an isolated mode of vibration on the form function that describes the backscattering. Calculated resonance widths as well as observed pulse decay times allow determination of analytical and experimental Q’s of isolated resonances.
Subject Classification: [43]20.30, [43]20.60, [43]20.50; [43]40.20.
Production of cochlear potentials by inner and outer hair cells
Authors: Dallos Peter , Cheatham Mary Ann 
Published: October 2005

Cochlear microphonic and summating potential recordings were obtained from preparations where only either inner hair cells (first-turn recording) or outer hair cells (fourth-turn recording) could have contributed to the potentials. A comparison suggests that outer hair cells do produce the preponderance of receptor potentials.
Subject Classification: [43]65.40, [43]65.42.
Gap detection: Two-channel detection of the missing event
Authors: Gilliom J. D. , Mills W. M. 
Published: October 2005

The ability to detect gaps in continuous sinusoids was studied in both single- and two-channel tasks. From single-channel tasks, psychometric functions were obtained. Pulse and gap functions were found to be essentially parallel, with gap detection being 3–4 dB poorer than pulse detection. In two-channel tasks, two-channel detection of gap signal events produced a lower level of performance than two-channel detection of pulse signal events. However, in an unusual condition where a gap stimulus produced what sounded like a pulse to the observer, performance in two-channel gap detection and two-channel pulse detection was quite similar. This latter result suggests (1) gap stimuli enter the system as efficiently as pulse stimuli, and (2) it is the system’s inferior ability to process perceptual gaps which leads to the lower performance normally observed in two-channel gap detection. In a fourth two-channel task which required the observer to detect gap stimuli in one channel and pulse stimuli in the other, no detrimental effect on performance could be detected—a result illustrating the flexibility of the two-channel processing mechanism. Implications of the results for the INR model of two-channel processing are discussed.
Subject Classification: [43]65.75, [43]65.58, [43]65.68.
Masking period patterns of harmonic complex tones
Authors: Zwicker E. 
Published: October 2005

Masking period patterns, i.e., the SPL of just audible triggered sequences of short high-frequency test tone bursts as a function of their temporal spacing throughout the period of a masker, were measured using the following maskers: low-frequency two-tone and three-tone complexes, Gaussian-shaped impluses and differentiated Gaussian impulses with both condensation and rarefaction peaks. The similarity between masking period patterns and neurophysiologically measured period histograms was confirmed with respect to the temporal structure. However, distinct differences appear in the amplitude structure of both patterns, indicating a strong nonlinearity involved in the transformation of the masker’s time function into the masking period pattern. Starting a few decibels above threshold in quiet, the peaks of the patterns are elevated by 10 dB for each 5-dB increment of masker level. This fact points towards a square law for high-frequency test signals and low-frequency maskers. The steepness of slope of the masking period pattern seems to reach a maximal value of 10 dB/msec. Relations between neurophysiological period histograms and corresponding masking period patterns as well as differences between the patterns produced by condensation and rarefaction peak maskers, respectively, are discussed.
Subject Classification: [43]65.58, [43]65.35, [43]65.68.
Acoustic propagation in shallow water overlying a consolidated bottom
Authors: Ingenito Frank , Wolf Stephen N. 
Published: October 2005

An experiment designed to measure normal mode amplitude functions and attenuation coefficients was conducted in shallow water on Campeche Bank off the Yucatan Peninsula. Measurements were made at two locations on the bank in water of about 30 m in depth over a bottom consisting of consolidated limestone having a measured and sound velocity of 1900 m/sec. Pulsed cw signals with frequencies of 400, 750, and 1500 Hz were used. Theoretical calculations of the mode amplitude functions using a fluid model of the bottom were found to agree well with the measurements. In order to reconcile the measured mode attenuation coefficients with theory, it was necessary to assume that the shear velocity of the bottom was 1000 m/sec. The latter is lower than the minimum sound velocity in the water column so that the generation of propagating shear waves in the bottom was the dominant attenuation mechanism. Significant differences in the measured mode attenuation coefficients at the two stations were explained by the deepening of the low velocity channel at the bottom of the water column.
Subject Classification: [43]30.20, [43]30.50.
Acoustic spectral analysis of three tornadoes
Authors: Arnold Roy T. , Bass Henry E. , Bolen Lee N. 
Published: October 2005

Three sound recordings of tornadoes have been spectrally analyzed over the frequency interval between 100 and 2000 Hz. The low-frequency analysis was limited by the response of the microphones used for the recordings; the upper frequency limit was imposed both the microphone response and the low-signal level. One recording was made by James Cramer of a tornado which passed through Clay Center, Kansas on 25 September 1973. A second recording was made by Richard Allen Lindley of a tornado that passed through Guin, Alabama on 3 April 1974, and a third recording was made by Tom Bittman of a tornado which damaged his home in Tulsa, Oklahoma on 8 June 1974. All of the recordings are of low quality and the audio information required major spectral corrections, but the data analysis does indicate that the audio emissions from the tornadoes decrease in intensity as a function of increasing frequency. An attempt has been made to correlate the data with real (and conjectured) physical characteristics of the tornadoes and attendent atmospheric phenomena. It is clear to us from an objective analysis (and the more difficult subjective evaluation of the recordings) that identification of tornadoes based on acoustic emissions is possible . A study of tornadic sounds can not only provide a new tool for gaining insight into electrical and mechanical disturbances within a tornadic storm, but will also allow acoustic detection of a tornadic storm. A study of the change in intensity of the sounds emitted by the approaching Guin storm at both high and low frequencies suggests that noises generated by the high-speed winds of the principal tornado vortex as its base scoured the ground might be discerned from noises generated by the winds of one or more smaller vortices moving around the tornado, and/or electrical discharges aloft.
Subject Classification: [43]28.45, [43]28.65.
Light-scattering heterodyne interferometer for vibration measurements in auditory organs
Authors: Dragsten P. R. , Webb W. W. , Paton J. A. , Capranica R. R. 
Published: October 2005

An interferometric optical heterodyne technique has been developed especially for vibrational amplitude and phase measurements on auditory organs of live animals. Laser light diffusely scattered from the vibrating structure is used for the measurement. Continuous calibration and feedback compensation systems were developed to cope with the problems of drift in interferometer alignment and small background movements. Vibrational amplitudes from below 0.1 Å to above 400 Å have been detected on the posterior tympanic membranes of live crickets.
Subject Classification: [43]65.20; [43]40.60; [43]35.65.