bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resonant vibrations of free cylinders and disks
Authors: Rasband S. N. 
Published: October 2005

A complete solution is obtained for nonaxisymmetric resonant vibrations of a free cylinder or disk involving infinite sums. For axisymmetric longitudinal vibrations an alternative to previous solutions is included. In principle, the solutions satisfy exactly the stress-free boundary conditions , in contrast to the approximate bending-mode solutions due to Pickett or approximate solutions based on a small diameter/length ratio and small shearing stresses at the ends.
Subject Classification: 40.26, 40.24; 20.40.
Reverberation performance of phase-correlating sonars
Authors: Miller Norman B. 
Published: October 2005

Processing gains against reverberation of phase-correlating sonar processors are compared with linear processors. Formulas are derived which predict reverberation test results obtained at low and moderately high sea states. The signals tested have time–bandwidth (TW) products in the range from 2 to 70, representing a variety of spectral shapes. Reverberation statistics data illustrate the variances of phase-correlator outputs as a function of Doppler. The phase correlator is a constant false-alarm device with maximum variance at zero Doppler of approximately (4 TWe)−1. A definition of the equivalent bandwidth We is derived for general signal spectral shapes and Doppler distributions in the medium. Phase-correlator response to reverberation depends upon signal bandwidth, integration time (pulse-length), and scatterer agitation. The measured Doppler spreading of reverberation is consistent with a normal distribution of scatterer velocities.
Subject Classification: 60.XX.
Gold and Pumphrey revisited, again
Authors: Green David M. , Wier Craig C. , Wightman Frederic L. 
Published: October 2005

We investigated two periodic sequences: (1) identical sinusoidal pulses repeated regularly in time and (2) a sequence in which alternate pulses were inverted. These are the same stimuli used by Gold and Pumphrey. An analysis of the spectra of these two pulse trains suggested that the critical cue for the discrimination between them is a pitch difference. This pitch difference is the result of a difference in the ripple in the power spectra of the stimuli. This analysis provides an explanation of Gold and Pumphrey’s results that does not require the assumption of extemely narrow tuning, as made in their analysis.
Subject Classification: 65.35, 65.60, 65.75.
Ultrasonic absorption in aqueous solutions of chondroitin sulfate
Authors: O’Brien W. D. 
Published: October 2005

Ultrasonic absorption and velocity were determined in aqueous solutions of chondroitin sulfate, the major sulfated mucopolysaccharide which is distributed throughout mammalian connective tissue, as a function of ultrasonic frequency (2.39–62.4 MHz), temperature (10 °–37 °C), and pH (0.85–13.3). A broad distribution of relaxation frequencies is required to describe the absorption spectra. The apparent activation energy is 3.7 kcal/mole at a concentration of 0.054 gm/cc and at neutral pH over the frequency range 8.87–50.5 MHz. It is suggested that the same absorption mechanism(s) may be responsible in aqueous solutions of chondroitin sulfate and dextran at neutral pH. The absorption peaks near pH 2.5 and 11.5 are typical of those observed for the proton-transfer mechanism.
Subject Classification: 80.20; 35.24.
Low-frequency sound attenuation in Baffin Bay
Authors: Mellen Robert H. , Browning David G. , Ross John M. , Merklinger Harold M. 
Published: October 2005

At low frequences, the attenuation in underwater sound channels appears frequently to be dominated by forward scatter from large-scale inhomogeneities. Propagation-loss measurements were made in Baffin Bay in September 1972, when there was a relatively strong sound channel with the axis depth near 100 m. The attenuation above 200 Hz shows a frequency-independent scatter loss of 0.02 dB/kyd. Below 200 Hz, the loss falls off as f4, and thus suggests Rayleigh scatter from inhomogeneities with a scale size near 3 m.
Subject Classification: 30.20.
Cochlear neurons: frequency selectivity altered by conductance change in scala tympani
Authors: Johnstone J. R. , Johnstone B. M. , Yates G. K. 
Published: October 2005

It has recently been reported that when perilymph is removed from scala tympani of guinea pig cochlea, the tuning curves of auditory nerve ganglion cells are seriously affected. This suggests that measurements of basilar membrane vibration under similar conditions may also be affected and not representative of the normal cochlea. Hence the discrepancy known to exist between neural tuning curves and basilar membrane tuning curves could be explained. We have confirmed the existence of this effect on neurons, but we present two kinds of evidence that it is not due to a basilar membrane change. First, the amount of perilymph which must be removed is greater than that routinely removed for mechanical measurements. Second, filling the scala with isotonic sucrose produces the same change. We conclude that removal of perilymph affects auditory neurons by changing the electrical properties of the cochlea and that the difference between tuning curves of the basilar membrane and ganglion cells is due not to a basilar membrane mechanical filter but to a second filter which acts at a later stage.
Subject Classification: 65.26, 65.28.
Effect of training on human underwater sound-localization ability
Authors: Stouffer James L. , Doherty E. Thomas , Hollien Harry 
Published: October 2005

Experimental evidence has suggested that humans have a moderately functional sound-localization capability underwater; it appeared appropriate to determine if this ability could be improved by training. Signals of 1000 Hz and 25 pps were presented to the subjects at five angles (to the head). Four sets of stimuli were employed: the first and last sets constituted the pre- and post-tests, respectively, and the middle sets were a training procedure where subjects were informed of the actual source location after each presentation. The obtained scores demonstrated a significant increase in correct responses for the 1000-Hz signal; improvement for 25 pps was not as great and did not show statistical significance.
Subject Classification: 65.62; 30.85.
Comments on ’’Lateralization and the binaural masking-level difference’’ [G. B. Henning, J. Acoust. Soc. Am. 55, 1259–1263, (1974)]
Authors: Yost William A. 
Published: October 2005

Henning [J. Acoust. Soc. Am. 55, 1259–1263 (1974)] showed that certain complex waveforms can be lateralized on the basis of interaural temporal differences when the energy in the waveforms is confined to high-frequency regions. However, when the high-frequency waveforms are presented in a background of noise, Henning showed that their detection is not dependent on interaural temporal differences. In the present demonstration experiment these high-frequency waveforms were not as easily lateralized with a noise background as were low-frequency stimuli. This result is consistent with an assumption that lateralization and binaural detection of complex waveforms are not essentially different.
Subject Classification: 65.62, 65.60, 65.58.
Interaural alternation, information load, and speech intelligibility
Authors: Wingfield Arthur , Wheale John L. 
Published: October 2005

Speaks and Trooien [J. Acoust. Soc. Am. 56, 640–644 (1974)] report a failure to replicate selective intelligibility loss typically associated with rapid alternation of speech between the two ears. Results from several studies show the effect to be real, but that listeners must be under some load for the loss to appear. This can be accomplished by requiring ’’shadowing’’ as a response measure, using linguistically complex messages, or increasing input rate of the speech signal.
Subject Classification: 70.30, 70.35.
Cetacean echolocation signals and a new model for the human glottal pulse
Authors: Altes R. A. , Evans W. E. , Johnson C. S. 
Published: October 2005

A theoretical explanation for cetacean sonar systems can also be applied to human speech. The theory leads to a mathematical model of the human glottal pulse that is considerably different from those employed in the past.
Subject Classification: 80.50; 70.20.
Ultrasonic heating of V
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Authors: Eames F. A. , Carstensen E. L. , Miller M. W. , Li May 
Published: October 2005

Irradiation of Vicia faba root tips with 2.3-Mhz ultrasound at 10 W/cm2 causes a small but measurable heating of the tips and an immediate reduction in root growth rate. Roots exposed to comparable temperature increments without ultrasound show no reduction in growth, thus leading to the conclusion that the mechanism responsible for the biological effects of ultrasound on roots is nonthermal. From the time course of ultrasonic heating of the roots it appears that the thermal conductivity of the root material is comparable to that of water, and the acoustic absorption coefficient of the root tissue is higher than that of mammalian tissues.
Subject Classification: 80.40; 35.75.
Sound-velocity perturbations due to low-frequency motions in the ocean
Authors: Mooers Christopher N. K. 
Published: October 2005

The properties of low- and intermediate-frequency external and internal waves in the open ocean, and the nature of the acoustic velocity perturbations they produce, are examined. The basic principles are illustrated with theoretical calculations based on representative oceanic cases. Such calculations provide a rational estimate for the vertical and horizontal dependence of the perturbation of the acoustic velocity field due to external and internal waves. External waves can cause travel-time fluctuations by their horizontal velocity fluctuations (or fluctuations in the total sound velocity). Internal waves can cause acoustic travel-time fluctuations both by their vertical displacement of isotherms (or isolines of sound speed) and by their velocity fluctuations (or fluctuations in total sound velocity). Both external and internal waves can have horizontal wavelengths ranging from a fraction of a kilometer to hundreds of kilometers. The longer waves can be effective in producing travel-time fluctuations over long propagation paths; the shorter waves are probably most influential in the scattering of acoustic energy.
Subject Classification: 30.20.
Vibration of generally orthotropic skew plates
Authors: Srinivasan R. S. , Ramachandran S. V. 
Published: October 2005

This paper presents a numerical method for finding the natural frequencies and mode shapes of generally orthotropic clamped skew plates subjected to in-plane forces. As illustrations, two aspects are considered. First, the natural frequencies and mode shapes of a rhombic plate (without any in-plane forces) are determined for different orientations of the axes of orthotropy. Marked changes in the mode shapes, which are not easily predictable, are found to take place. Secondly, the influence of in-plane forces (both unidirectional tension/compression and uniform shear) on the natural frequencies is studied. The results indicate that in all cases but one the relationship between the square of the frequency and the in-plane force is nonlinear. The numerical method employed makes use of integral equations of beams with appropriate boundary conditions, along the skew coordinates, for transforming the governing differential equation into a set of algebraic equations. These equations are then solved to find the eigenvalues and eigenvectors.
Subject Classification: 40.24.
N-parameter ducts
Authors: Molloy Chuck 
Published: October 2005

The exact solution to Webster’s differential equation for sound in an initial variable area duct is used to generate new families of duct shapes with their exact solutions. In most cases the shapes and their solutions may be expressed in terms of nth-order determinants (Wronskians, in fact) whose elements are solutions to the initial duct and derivatives of these solutions. The nth-order determinant contains 2n+1 arbitrary parameters which are available for the design of ducts. The initial duct may be any duct for which the solution to Webster’s equation is known. The method is applied to a uniform duct to derive new families of ducts where both the duct shape and its solution are expressed in closed form in terms of elementary functions. Special cases include filters, constrictions, and new horn shapes in addition to the well-known conical horn, Bessel horns, the exponential horn, the Salmon horn, and the sinusoidal duct.
Subject Classification: 20.45; 85.60.
Some relations between energy yield of atmospheric nuclear tests and generated infrasonic waves
Authors: Flores José S. , Vega Angel J. 
Published: October 2005

The relation between energy yield in megatons (MT) of atmospheric tests during 1968–1971 at French Polynesia and infrasonic waves recorded at Peñas in Bolivia (a distance of approximately 7300 km) is studied. Yields were estimated from period and amplitude of the early portion of the waveforms using the theoretical relation of Pierce and Posey [Geophys. J. R. Astron. Soc. 26, 341–368 (1971)]. In the present paper, the relation of this derived yield to the Power spectrum of major portions of the waveforms is investigated. The magnitude of the square root of this spectrum that can be considered proportional to the Fourier Integral for a Yield Sample Time (i.e., spectral amplitude) typically has two characteristic peaks, the first of which appears to nearly directly proportional to yield, the proportionality constant being 300 μbar sec1/2/MT. Another waveform feature exhibiting strong correlation with yield is the time duration of the gravity wave train which precedes the acoustic mode waves. For smaller yields, this also appears to vary nearly linear with yield, the proportionally constant being 1000 sec/MT up to about 1 MT. The application of these conclusions to other source–receiver geometries and to other meteorological conditions remains a topic for future study.
Subject Classification: 28.20, 28.30.
Relations among temporal resolution, forward masking, and simultaneous masking
Authors: Smiarowski Richard A. , Carhart Raymond 
Published: October 2005

The data from this investigation suggest that both temporal resolution and forward masking are the products of a single underlying mechanism of auditory persistence. Persistence of auditory activity from a burst of noise not only limits the listener’s ability to perceive a trailing noise burst as temporally separate (temporal resolution), but also interferes with his detection of a click that follows the burst of noise (forward masking). After a relatively stable initial period of about 2.5 msec, the magnitude of this persisting residual activity decays linearly over log time, as evidenced by the progressive reduction in the level of both the trailing noise burst in temporal resolution and the click threshold in forward masking. The data also indicate that forward masking of the click bears the same relationship to masker level as does simultaneous masking of the click. The mechanisms of forward masking may be essentially the same as those for simultaneous masking, except that for the former the masking process is a residue that persists from prior stimulation.
Subject Classification: 65.58, 65.75.
Factors in the discrimination of tonal patterns. I. Component frequency, temporal position, and silent intervals
Authors: Watson Charles S. , Wroton Henry W. , Kelly William J. , Benbassat Carole A. 
Published: October 2005

Factors which determine the discriminability of tonal sequences, or patterns, were investigated in five experiments. The patterns were generally sequences of ten 40-msec tonal components, which ranged in frequency from 256 to 900 Hz, or from 500 to 1500 Hz, in equi-log intervals. Highly trained (15 to 60 h of training prior to collecting experimental data) listeners’ abilities to detect changes in the frequency of single tonal components in these patterns were measured using a same–different psychophysical method. The just-detectable values of Δf (d′=1.0) were only slightly larger than for single 40-msec tones presented in isolation for tonal components at the end of the temporal sequences (a ’’recency’’ effect). Performance was systematically worse for earlier components, the just-detectable Δf increasing by four to five times from the end of the pattern to the beginning (no ’’primacy’’ effect). The ’’recency’’ effect was interpreted as a matter of later arriving components interfering with frequency resolution for earlier ones, since a brief silent period (80 to 120 msec) following an early component led to as precise discrimination for that early component as for the last one in the sequence. The higher-frequency components in a given pattern were resolved much more accurately than the lower-frequency components for patterns with overall bandwidths of 250 to 900 Hz and also when the bandwidths were raised from 500 to 1500 Hz.
Subject Classification: 65.22, 65.75, 65.64.
New formula for calculating acoustic propagation loss in a surface duct in the sea
Authors: Baker William F. 
Published: October 2005

The new formula described has been derived as an empirical fit to experimental data, and gives improved accuracy compared with an earlier formula. Mean errors of typically ± 2 dB, with a standard deviation of 7 dB, have been obtained. The variation of propagation loss with depth has not been investigated.
Subject Classification: 30.20.
Comparison of an acousto-optic and a radiation force method of measuring ultrasonic power
Authors: Haran Michael E. , Cook Bill D. , Stewart Harold F. 
Published: October 2005

During the interim period while nationally acceptable methods of measurement of referential standards for ultrasonic power are being developed, comparisons are needed among measurment techniques currently used. This is particularly necessary for determining the acoustic power from ultrasonic medical devices. Such a comparison was made between an optical and a radiation force technique to measure the ultrasonic power output of a 1-MHz 1-in.-diameter PZT crystal from 70 mW to 2.3 W total acoustic power. The optical technique follows the theory of Raman and Nath, assaying the diffraction of monochromatic light by ultrasound. In addition, a correction factor is introduced into the calculation of the phase retardation parameter and eliminates the need to determine the pathlength of the light through the sound. The radiation force technique relates the change of position of an air-backed, self-centering, reflecting float to the ultrasonic power. A linear regression analysis between the square of the voltage applied to the crystal and the measured power of each method was used. For a 99% confidence level, there is no statistical difference between the measurements over the range of power investigated, although the variance of the optical measurements was significantly lower than that of the radiation force.
Subject Classification: 35.65, 35.80; 85.24.
Ultrasonic attenuation and velocity in two-phase microstructures
Authors: Latiff R. H. , Fiore N. F. 
Published: October 2005

The scattering attenuation and velocity of elastic waves propagating in two-phase microstructures are computed by an extension of multiple scattering analysis. The computation is based on a model of an array of isotropic spherical scatterers embedded in an isotropic matrix. Attenuation α is predicted to increase with volume fraction and number density of scatterers and to approach a plateau with frequency. Group velocity vg is predicted to decrease with volume fraction and frequency. Ultrasonic measurements of α and vg are made on model microstructures consisting of Cu spheres embedded in a polymethylmethacrylate matrix. The measured values agree qualitatively with the predicted ones, and physical reasons are proposed to account for the agreement. The inability of the theory to provide accurate quantitative predictions of these quantities is discussed.
Subject Classification: 35.26; 20.30, 20.35.
Damping measurements of a controlled composite material
Authors: Jones E. R. , Sierakowski R. L. , Ross C. A. 
Published: October 2005

Increased use of filamentary materials as reinforcements in structural components has necessitated obtaining information on the response of such material systems to a wide variety of loading conditions. One such technically important problem area is that associated with the dynamic response of composite materials to impact-type loading situations. In order to understand the phenomenon of wave travel in material systems, specific knowledge of the damping coefficient and phase velocity as a function of circular frequency is necessary. In the present paper, tests are reported for beam-type specimens of a steel–epoxy composite having controlled volume fractions and varying wire sizes. Measurements are reported on the damping coefficient as a function of circular frequency a (ω) and the real part of the complex modulus E1. The latter parameter has been further used to calculate the phase velocity, and data are presented on phase velocity c (ω) as a function of frequency. Detailed tabular and graphical data are presented for the various specimens tested.
Subject Classification: 40.20, 40.22.
Acoustic pulse techniques for the nondestructive determination of material parameters
Authors: Mattei Michael D. , Shapton William R. 
Published: October 2005

The natural frequencies and damping properties of physical systems have provided investigators with valuable information for solving various problems associated with vibrating structures. This paper uses the information associated with natural frequencies and damping in order to determine two physical parameters of a material. Using pulse excitation and noncontacting instrumentation, acoustic methods are presented for nondestructively determining Young’s modulus and martensite start transformation temperature. The material used for this investigation was a nickel titanium alloy referred to as Nitinol. There is no reason, however, that the procedures and techniques described in this paper cannot be used for a variety of other materials.
Subject Classification: 40.60; 40.20.
Contribution of the external auditory meatus to auditory sensitivity underwater
Authors: Hollien Harry , Feinstein Stephen 
Published: October 2005

Support for, and a refinement of, the hypothesis that divers hear primarily by bone conduction was provided by Hollien and Brandt [J. Acoust. Soc. Am. 46, 384–387 ( 1969)]. To further test this hypothesis, the thresholds of seven submerged listeners were obtained (at frequencies of 0.25, 0.50, 1.0, 4.0, and 8.0 kHz) under three different conditions; (1) while they wore a full 3/16-in. wet suit with no hood, (2) while wearing a full 3/16-in. wet suit with a 3/16-in. hood, and (3) while wearing a full 3/16-in. wet suit and hood with 1/4-in. rubber tubes passing through the hood to the external auditory meatuses. There were no significant differences between the conditions involving the use of a hood but thresholds were significantly lower in the middle and high frequencies for the no-hood condition. These findings provide further support for the hypothesis that underwater sound energy is transduced predominantly by bone conduction rather than by the normal middle ear linkage.
Subject Classification: 65.50; 30.10; 65.22.