bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small−amplitude sinusoidal waves in an elastic mixture with binary chemical reactions
Authors: Nunziato Jace W. , Walsh Edward K. 
Published: October 2005

The propagation of small−amplitude sinusoidal waves in a chemically reacting mixture of nonconducting elastic materials is considered. Limiting attention to mixtures with binary reactions, we derive expressions for the phase velocity and attenuation of infinitesimal sinusoidal waves and examine the influence of the thermochemical properties of the mixture on the wave behavior. The general relation between small−amplitude sinusoidal waves and acceleration waves is also established.
Subject Classification: 35.26.
High−frequency vibrations of crystal plates under initial stresses
Authors: Lee P. C. Y. , Wang Y. S. , Markenscoff X. 
Published: October 2005

A system of six two−dimensional plate equations is derived for motions of small−amplitude waves or vibrations superimposed on finite, elastic deformations due to static, initial stresses. In the stress−strain relations, the nonliner terms associated to the third−order elastic stiffness coefficients are included. These equations accomodate the coupling of the six lowest modes of vibration, i.e., the flexure, extension, face−shear, thickness−shear, thickness−twist, and thickness−stretch modes, and all their anharmonic overtones. The new equations are applied to the rotated Y cuts of quartz in studying the thickness−shear and flexural vibrations. The changes in the resonance frequencies of the fundamental thickness−shear vibrations are computed as functions of the direction of initially applied force and of the angle of rotated Y cuts. The predicted results are compared with experimental data and with existing computed results. An explicit formula is obtained for the change of fundamental thickness−shear frequencies in terms of initial deformations and the second− and third−order elastic stiffness coefficients.
Subject Classification: 40.24.
Loudness enhancement in man. I. Brainstem−evoked response correlates
Authors: Bauer J. W. , Elmasian R. O. , Galambos R. 
Published: October 2005

This paper correlates electrophysiological responses and psychophysical judgments in subjects performing in a loudness enhancement task. Subjects received a tone burst Tc followed after an interval (ΔT) by a signal S1 whose loudness they were required to match by adjusting the intensity of another signal S2 presented 1.5 sec later. They judged the loudness of S1 to be enhanced by 15 dB or more when ΔT was small. Analysis of the electrophysiological brainstem responses evoked by S1 and S2 (as recorded via scalp electrodes) revealed no changes in the electrophysiological response to S1 that could explain its loudness enhancement. A latency measure decreased and a power spectrum measurement increased for both S1 and S2 as their physical intensity was raised, but presenting Tc prior to S1 had either no effect or the opposite effect by either measure despite the large perceived enhancement of S1 loudness. These results show the brainstem response to reflect stimulus intensity changes accurately, and perceived (enhanced) loudness change poorly or not at all. The mechanisms mediating loudness enhancement probably operate, therefore, at levels central to the brainstem.
Subject Classification: 65.44, 65.50.
Interaural phase and amplitude relationships of bone−conduction signals
Authors: Tyszka Frederic A. , Goldstein David P. 
Published: October 2005

Masking level differences (MLDs) were used as a means of studying the interaural phase and amplitude relationships for a 500−Hz bone−conduction signal from both the mastoid and the forehead vibrator positions. The results of the investigation indicated that with the vibrator on the forehead there is a trend for a 500−Hz bone−conduction signal to be interaurally in phase and interaurally equal in amplitude. With the vibrator on the mastoid there is a trend for the bone−conduction signal to be 180° interaurally out of phase and interaurally equal in amplitude.
Subject Classification: 65.62, 65.60, 65.58.
Stimulus familiarity and ear superiority in dichotic listening
Authors: Nachshon Israel , Carmon Amiram 
Published: October 2005

The effects of speech lateralization, stimulus familiarity, and their interaction on ear superiority in dichotic listening were investigated. In two tests, dichotic pairs of consonant−vowel monosyllables were presented. In the first test, the consonants, and in the second, the vowels, varied, while the other member of each monosyllable was kept constant. In each test, the varying stimuli had to be identified. Four conditions were created in each test by pairing either two familiar or two nonfamiliar monosyllables, or familiar with nonfamiliar monosyllables. Consonants were better identified from the right ear, except when familiar consonants in the left ear were paired with nonfamiliar consonants in the right ear. Vowels were identified equally well from the two ears when both vowels in the dichotic pairs were equally familiar or nonfamiliar. When familiar vowels were paired with nonfamiliar vowels, the familiar vowels were always better identified. The results thus show that the differential report from the two ears is affected by both stimulus familiarity and language lateralization.
Subject Classification: 70.30.
Two 50% probabilities
Authors: Andrews Frank A. 
Published: October 2005

The concept, detection probability, is used in two different ways in assessing sonar performance. In both cases, the value 50% appears frequently. The first use occurs in the detection process itself, where the signal−to−noise power required for a detection probability of 50% is usually called ’’recognition differential’’ and sometimes ’’detection threshold.’’ The second use occurs in the prediction of the sonar range under conditions of uncertainty. In this latter case, the range at which one−half the members of an ensemble of targets and environmental conditions will be detected is often called ’’50% probability detection range.’’ The relation between the two probabilities will not be found in standard text books on sonar systems, and is therefore submitted here.
Subject Classification: 60.10.
Fundamental frequency rules for the synthesis of simple declarative English sentences
Authors: Olive Joseph P. 
Published: October 2005

A recent experiment by Olive and Nakatani [J. P. Olive and L. H. Nakatani, ’’Rule−synthesis of speech by word concatenation: a first step,’’ J. Acoust. Soc. Am. 55, 660−666 (1974)] has shown that when telephone numbers were rule−synthesized by splicing together numbers which were spoken in isolation, the proper adjustment of fundamental frequency was more important than adjustments of amplitude, duration, and between word coarticulation, for making these spliced numbers sound as if they were spoken naturally. This experiment also showed that in the case of telephone numbers, fundamental frequency adjustments were sufficient for providing synthesis by rule of quality comparable to the quality of natural speech which was processed by an analysis−synthesis procedure. This paper describes the next step in our research of rule synthesis: the study of a restricted set of sentences of simple syntactic structure, instead of telephone numbers. Methods for studying fundamental frequency contours of naturally spoken sentences are discussed; some fundamental frequency rules for synthesizing short English sentences are derived from these natural utterances. More specifically, only rules which are dictated by the syntax were investigated; the appropriateness of these rules was determined by incorporating them into a computerized rule−synthesis scheme.
Subject Classification: 70.50.
Scattering−matrix description and nearfield measurements of electroacoustic transducers
Authors: Kerns D. M. 
Published: October 2005

Recently developed and successfully applied analytical techniques for the measurement of microwave antennas at reduced distances are ’’translated’’ into corresponding techniques for the measurement of electroacoustic transducers in fluids. The basic theory is formulated in scattering−matrix form and emphasizes the use of plane−wave spectra for the representation of sound fields. This theory, in contrast to those based on asymptotic description of transducer characteristics, is suitable for the formulation and solution of problems involving interactions at arbitrary distances. Two new techniques (in particular) are described. One, utilizing deconvolution of transverse scanning data, taken with a known tranducer at distances d which may be much less than the Rayleigh distance dR(≡ D2/2), provides a means of obtaining complete near− and farfield characteristics, corrected for the effects of the measuring transducer. Applicability of a (two−dimensional, spatial) sampling theorem and the ’’fast Fourier transform’’ algorithm, which greatly facilitate the necessary computations, is shown. The second technique provides a means of extrapolating received signal as a function of distance (observed with d ∠ dR) to obtain on−axis values of effective directivity. Other possible applications are indicated. These techniques rigorously utilize observed transducer output, which need not be simply related to pressure or normal velocity at a point.
Subject Classification: 85.40, 85.62; 30.85.
New acoustic resonator for liquids in the 0.2− to 2−MHz range
Authors: Eggers F. , Funck Th. 
Published: October 2005

A new acoustic resonator with nonplanar quartz transducers for liquids (sample volume about 20 ml) in the 0.2− to 2−MHz range is described. The application of static overpressure onto the liquid cavity causes concave bending of both quartz transducers. This reduces loss contributions from diffraction and ’’side−wall effects’’ considerably, resulting in higher Q values for this resonator; moreover, air inclusions in the cavity are suppressed.
Subject Classification: 35.24, 35.80.
Distribution of natural frequencies in certain structural elements
Authors: Elishakoff I. 
Published: October 2005

The paper deals with the natural frequency distribution in beams, plates, and shallow spherical shells. Expressions are found for the distribution functions (number of modes not exceeding a given cutoff level), for these integral approximations, and for the frequency derivatives of the latter—the so−called smeared modal densities. Special attention is paid to the singularities in these densities (present in certain elements), which were noted by Bolotin and are referred to in literature as ’’condensation points.’’ It is shown that omission of the concept of lowest natural frequency leads to a physical paradox, and that the findings of most studies of modal densities should be revised. The method of integral approximations is applied to the problem of random vibrations of a shallow spherical viscoelastic panel. It is shown that the integral approximation of the averaged spectral density in the high−frequency range is equivalent to an infinite−system model, and, moreover that the physically inconsistent results reported in literature regarding infinite discontinuities in the spectral densities of damped shells are erroneous and due to application of asymptotic expressions, valid only at high frequencies, to the low−frequency range.
Subject Classification: 40.22, 40.24, 40.26, 40.35.
Comparison of Statistical Energy Analysis power flow predictions with an ’’exact’’ calculation
Authors: Remington Paul J. , Manning Jerome E. 
Published: October 2005

Statistical Energy Analysis (SEA) predictions of the power flow between two multimodal dynamic systems, i.e., two rods vibrating in compression, are compared with an exact calculation. The exact calculation when averaged in sufficiently broad frequency bands is found to agree closely with the SEA predictions for both strong and weak coupling.
Subject Classification: 45.40.
Chamber for reverberant acoustic power measurements in air and in water
Authors: Blake William K. , Maga Lawrence J. 
Published: October 2005

A reverberant chamber for use with both air and water media is described. The chamber is used to investigate the acoustic coupling of simple vibrating structures under conditions of light or of heavy fluid loading. Calibration was effected by measuring 60−dB reverberation times in 1/3−octave bands; decay times on the order of 2 sec in air and the order of 0.2 sec in water were observed. These results were cross checked in water by measuring the spectrum of acoustic pressure in the chamber generated by a calibrated hydrophone source. Sound−pressure levels measured in narrow (50−Hz) bands varied ±3 dB spatially in the air−filled chamber and ±5 dB spatially in the water−filled chamber.
Subject Classification: 55.65; 50.25; 45.10.
Mechanisms of masking
Authors: Moore B. C. J. 
Published: October 2005

Some of the strategies which an observer might use in detecting a tone presented against a background of noise are discussed. In Experiment I thresholds for tones in noise were measured under a number of different conditions, using flat−spectrum and notch−filtered noises, in a two−interval forced−choice task. Threshold did not correspond to a constant difference in critical−band levels on the two halves of the trial. Performance at the highest frequency used (6.1 kHz) was worse than at lower frequencies (1055 and 4080 Hz), and, in contrast to them, was not independent of overall level. This is contrary to the classical data, and indicates that the critical ratio is not a constant fraction of the critical band. In Experiment II the intensity discrimination of 1/3−octave bands of noise was studied. The noises were presented alone or in a wide−band noise background. For noise bands presented alone, performance is roughly independent of overall level, and improves slightly with increasing center frequency. For noise bands presented against a wide−band noise background, performance is independent of overall level for frequencies up to 4 kHz. A change in level of about 2−3 dB is necessary for 75% correct detection. For frequencies above this, performance worsens with increasing overall level. These results may be explicable in terms of a saturation of neurons at high intensities. The saturation effects are not observed at low frequencies, possibly because the primary cue for detection is a change in the temporal pattern of neural firing, rather than a change in amount of neural firing.
Subject Classification: 65.58, 65,35.
Finite−element approach to acoustic scattering from elastic structures
Authors: Hunt John T. , Knittel Max R. , Nichols Charles S. , Barach Don 
Published: October 2005

An approximate method is presented for solving the equations of motion that describe the scattering of an acoustic wave by an elastic structure immersed in an infinite fluid medium. The mathematical model that is developed uses the finite−element method to calculate the vibrational response of the elastic body and to calculate the acoustic pressure field of a finite volume of the fluid medium which closely surrounds the elastic body. Analytical methods are used to obtain the boundary conditions for this mathematical model. Results are presented for the total scattering cross section, axial pressure, and scattering patterns for an acoustic plane wave at normal incidence on an aluminum disk.
Subject Classification: 30.30, 30.40.
Predictions of volume scattering strengths from biological trawl data
Authors: Love Richard H. 
Published: October 2005

A volume reverberation model which utilizes fish distribution data has been developed to permit quantitative predictions of depth−dependent scattering strengths. The model was evaluated by using coincident acoustic volume scattering measurements and biological trawl data collected in the Mediterranean Sea. Biological specimens were collected at discrete depths with an Isaacs−Kidd midwater trawl. Each fish collected was identified and sized, and its acoustic cross section calculated by utilizing regression equations relating fish species, length, and swimbladder volume at frequencies near swimbladder resonance, or equations relating fish length to acoustic cross section at frequencies far above resonance. Scattering strengths for each species were then determined, indicating dominant species at each trawl depth for 1/3−octave frequency bands between 2.5 and 20 kHz. The acoustic data were obtained with surface−vented explosive sources and a shallow onmidirectional hydrophone. These data were processed to yield integrated column strength versus depth profiles, which were then numerically differentiated to produce scattering strength versus depth profiles for each frequency band. Comparison of the model predictions to the scattering strength profiles showed good agreement at the higher frequencies, with the agreement decreasing with frequency below 6.3 kHz.
Subject Classification: 30.30, 30.40.
Sound propagation and attenuation in the deep ocean at very long ranges
Authors: Nomady V. G. , Überall H. 
Published: October 2005

Sound propagation in a deep−ocean sound channel is investigated theoretically. A normal−mode series solution which includes effects due to curvature of the earth is obtained as the residues in a pole series arising from the Watson transformation. Analytic expressions are found for the pressure amplitudes due to a continuous wave source using an Epstein sound velocity profile. Attenuation−versus−range curves are given for both phased and random modal sums. The continuous wave solutions are then used for the pulsed source problem. Dispersion curves are obtained. The higher−order modes are shown to arrive earlier, in agreement with experiment. An analytic expression for the pressure of a pulse as a function of time is obtained. The shape of the pulse at a range of several hundred miles is shown and agrees qualitatively with experimentally obtained pulse shapes. Such pulses begin at a low amplitude, increase to a relatively large amplitude peak, then cut off abruptly.
Subject Classification: 30.20.
Reaction−time procedure for measurement of hearing. I. Suprathreshold functions
Authors: Pfingst Bryan E. , Hienz Robert , Kimm Joseph , Miller Josef 
Published: October 2005

Reaction time (RT), or response latency, to auditory stimuli has been suggested as a measure of loudness in nonverbal animals as well as in man. In this study RT functions were obtained for human and rhesus monkey subjects under normal conditions and under conditions of hearing impairment. In both humans and monkeys RT varied in a similar manner with changes in intensity and frequency of the stimulus, and in response to experimental manipulation of the receptor organ. The study demonstrated that latency functions are similar to functions derived by loudness−matching procedures in humans: in subjects with normal hearing, equal−latency contours corresponded closely with equal−loudness contours. In subjects with impaired hearing, matched−latency and matched−loudness contours also corresponded closely. Rate of decrease in RT with increasing intensity is discussed and related to rate of growth in loudness. The results suggest that RT is a valuable measure of suprathreshold hearing in human and nonhuman primates.
Subject Classification: 65.50, 65.64, 65.66, 65.75; 85.24.
Acoustic characteristics of English /w,r,l/ spoken correctly by young children and adults
Authors: Dalston Rodger M. 
Published: October 2005

This report presents the results of a spectrographic analysis of word−initial allophones of /w/, /r/, and /l/ produced by three− to four−year−old children and adults. Information was obtained concerning formant frequencies, steady−state durations, transition durations, and transition rates of each of the first three formants of these sonorants. The results demonstrate that the phonemes investigated are distinguishable on the basis of their temporal, as well as their spectral, acoustic characteristics.
Subject Classification: 70.20, 70.40.
Assessment of hearing handicap: comment on the ’’Kryter series’’
Authors: Noble William G. 
Published: October 2005

The assessment of hearing handicap resulting from exposure to noise has been extensively discussed by Kryter [J. Acoust. Soc. Am. 53, 1211−1234 (1973)] and by subsequent commentators. It is argued that many problems and relevant findings on this issue have been overlooked in that series. It is further argued that a measure based on self−report holds more promise for the valid assessment of hearing handicap resulting from noise−induced hearing loss than performance tests of auditory pure−tone sensitivity or speech reception.
Subject Classification: 65.64.
Quantitative measurements of acoustic emission related to its microscopic mechanisms
Authors: Hatano Hajime 
Published: October 2005

A method for the quantitative measurements of the acoustic emission is worked out. Its performance is analyzed with regard to the transducer loss and the ultrasonic attenuation in the specimen. This method is actually applied to the tension tests of pure aluminium specimens. The power spectrum of the acoustic emission is obtained over a wide range of 100 kHz to 4 MHz. The total power attains a peak of 5 pW at the beginning of the plastic deformation and decreases to 0.3 pW with the increase of the deformation. The autocorrelation function for the acoustic emission is given as a monotonically decreasing function. This result reveals that the elastic energy of the acoustic emission is radiated not oscillatorily but in the form of random pulses. Mean value of the pulse widths is estimated to change from 0.6 to 0.2 μsec in the early stages of the deformation. This change is shown to be attributable to the increase of the density of dislocations in the material.
Subject Classification: 35.10.
Radiation of sound from a small loudspeaker located in a circular baffle
Authors: Lauchle Gerald C. 
Published: October 2005

The exact theory for the radiation of a small loudspeaker in the surface of a rigid circular disk of elliptic profile is presented. Numerical results are included for a monopole at the center of the disk and on its surface. The solution for the loudspeaker in the center of a free circular baffle is then formulated by superimposing the solution of a positive source on one side of the baffle with that for a negative source on the other side. For wavelengths greater than the circumference of the baffle, the resulting field turns out to be very similar to that of a dipole of finite dipole axis. However, for wavelengths smaller than the diameter of the baffle, the diffraction field is shown to be dominated by edge effects. In particular, the total field may also be represented by a simple ring−point source combination, i.e., the edge of the baffle is essentially replaced by a ring source. It is shown that in the vicinity of the axis of the baffle, the shape of the frequency response curve depends little on how much volume flow is generated on the opposite side of the baffle. In other words, it makes little difference (except in absolute level) whether a loudspeaker is enclosed in a box or is permitted to radiate from the rear.
Subject Classification: 20.15, 20.30, 20.55.
Acoustic reflection and transmission characteristics for thin plates
Authors: Barnard G. R. , Bardin J. L. , Whiteley J. W. 
Published: October 2005

A method for determining the acoustic properties of thin plates is described. Existing theoretical expressions are used to calculate transmission and reflection coefficients for sound waves striking the plates at arbitrary angles of incidence. Theory is substantiated by experimental data, and refined values for absorption coefficient and shear velocity are obtained by combining theory and experiment. Materials tested were Absonic−A, plexiglass, and polyethylene.
Subject Classification: 30.30, 30.50, 20.30.