Showing papers in "Journal of the Acoustical Society of America in 1976"
TL;DR: The theoretical and practical use of image techniques for simulating the impulse response between two points in a small rectangular room, when convolved with any desired input signal, simulates room reverberation of the input signal.
Abstract: Image methods are commonly used for the analysis of the acoustic properties of enclosures. In this paper we discuss the theoretical and practical use of image techniques for simulating, on a digital computer, the impulse response between two points in a small rectangular room. The resulting impulse response, when convolved with any desired input signal, such as speech, simulates room reverberation of the input signal. This technique is useful in signal processing or psychoacoustic studies. The entire process is carried out on a digital computer so that a wide range of room parameters can be studied with accurate control over the experimental conditions. A fortran implementation of this model has been included.
3,720 citations
TL;DR: It is concluded that duration often serves as a primary perceptual cue in the distinctions between inherently long verses short vowels, voiced verses voiceless fricatives, phrase‐final verses non‐final syllables, and the presence or absence of emphasis.
Abstract: The pattern of durations of individual phonetic segments and pauses conveys information about the linguistic content of an utterance. Acoustic measures of segmental timing have been used by many investigators to determine the variables that influence the durational structure of a sentence. The literature on segmental duration is reviewed and related to perceptual data on the discrimination of duration and to psychophysical data on the ability of listeners to make linguistic decisions on the basis of durational cues alone. We conclude that, in English, duration often serves as a primary perceptual cue in the distinctions between (1) inherently long verses short vowels, (2) voiced verses voiceless fricatives, (3) phrase‐final verses non‐final syllables, (4) voiced versus voiceless postvocalic consonants, as indicated by changes to the duration of the preceding vowel in phrase‐final positions, (5) stressed verses unstressed or reduced vowels, and (6) the presence or absence of emphasis.Subject Classification...
1,292 citations
TL;DR: A wide‐band noise having a deep notch with sharp edges was used to mask a tone and 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.
Abstract: 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.
658 citations
TL;DR: Forced oscillations of a spherical gas bubble in an incompressible, viscous liquid (water) are calculated numerically in this paper and the information gathered is mainly displayed in the form of frequency response curves of the steady-state solutions showing the harmonics, subharmonics, and ultraharmonics.
Abstract: 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.
453 citations
TL;DR: In this article, the detection factor DF = ΣJj=1 cjc*k (c0jc0k*) * ǫ * * � is proposed as a reasonable measure for determination of whether a set of sound pressure measurements is a good fit to calculated values of {cj} for an assumed location of the sound source.
Abstract: The calculated complex sound field cj for sensor j at depth zj and range rj from a sound source of frequency ω and depth z0 can be written in the normal‐mode form as cj= (2π/rj)1/2 ΣmUm(z0) Um(zj) exp[i (kmrj−ωt)]. Here, km is the horizontal wavenumber of mode m and Um is the depth function of the mth mode. It is proposed that the detection factor DF=ΣJj=1 cjc*k〈 (c0jc0k*) *〉 is a reasonable measure for determination of whether a set of sound pressure measurements {c0j} for j=1,2,⋅⋅⋅,J is a good fit to calculated values of {cj} for an assumed location of the sound source. Here 〈 〉 denotes a time average and * denotes complex conjugate. Several examples are shown where a set of {c0j} are calculated for a given source location in a typical shallow water channel and values of DF are then calculated for a grid of range depth or range azimuth locations.Subject Classification: [43]60.20; [43]30.82.
444 citations
TL;DR: Mongolian gerbils were trained to respond to pure tones in a shock‐avoidance task and thresholds derived from psychometric functions were essentially identical to those obtained by the method of limits.
Abstract: Mongolian gerbils were trained to respond to pure tones in a shock‐avoidance task. The animals proved to be readily trainable and behaviorally stable. Thresholds were obtained by a method of limits and, in the case of one animal, by generating psychrometric functions. The gerbil responds to frequencies between 0.1 and 60.0 kHz. For pure tones between 1.0 and 16.0 kHz, the threshold of hearing averages 4.6 dB SPL. Between 1.0 and 0.1 kHz, sensitivity declines at a rate of 12 dB/octave. Between 16.0 and 40.0 kHz, threshold increases at a rate of 13 dB/octave, and above 40.0 kHz at a rate of 66 dB/octave. Thresholds derived from psychometric functions were essentially identical to those obtained by the method of limits. Hearing in this species is consistent with its size and anatomical characteristics.Subject Classification: [43]80.50; [43]65.50.
313 citations
TL;DR: In this paper, the harmonics of the desired voice in the Fourier transform of the input were selected to distinguish between two different voices. But the authors focus on the principal subproblem, the separation of vocalic speech.
Abstract: A common type of interference in speech transmission is that caused by the speech of a competing talker. Although the brain is adept at clarifying such speech, it relies heavily on binaural data. When voices interfere over a single channel, separation is much more difficult and intelligibility suffers. Clarifying such speech is a complex and varied problem whose nature changes with the moment‐to‐moment variation in the types of sound which interfere. This paper describes an attack on the principal subproblem, the separation of vocalic speech. Separation is done by selecting the harmonics of the desired voice in the Fourier transform of the input. In implementing this process, techniques have been developed for resolving overlapping spectrum components, for determining pitches of both talkers, and for assuring consistent separation. These techniques are described, their performance on test utterances is summarized, and the possibility of using this process as a basis for the solution of the general two‐tal...
294 citations
TL;DR: In this article, the authors measured the stress-induced changes in ultrasonic wave speeds in several samples of steels typically used in railroad rails and derived the third-order elastic constants from the acousto-elastic data.
Abstract: Measurements of the stress‐induced changes in ultrasonic wave speeds in several samples of steels typically used in railroad rails are presented. All of the five possible relative changes in wave speeds for an initially isotropic material subjected to a uniaxial state of stress have been determined and agree to within the limits of accuracy of the measurement with the second‐order theory of Hughes and Kelly. The third‐order elastic constants are calculated from the acoustoelastic data.
281 citations
TL;DR: In this paper, Helmholtz and Kirchhoff-type integral formulas for elastic waves in isotropic and anisotropic solids are presented for the displacement vector field at points interior and exterior to a region bounded by a closed surface.
Abstract: Helmholtz‐ and Kirchhoff‐type integral formulas are presented for elastic waves in isotropic and anisotropic solids The displacement vector field at points interior and exterior to a region bounded by a closed surface is expressed in terms of a volume integral of the body sources and a surface integral of the sources on the closed surface, namely, the traction and the displacement The kernels of these integrals are the well‐known Green’s displacement dyadic and a third rank Green’s stress tensor The latter is related to the former by generalized Hooke’s law From these formulas radiation conditions for both steady‐state and transient elastic waves are established in terms of the traction, displacement, and particle velocity In the Kirchhoff‐type formula, the retardation in time for the surface and volume sources is made with respect to the travel times for dilatational and shear waves, respectively This clearly illustrates Huygens’ principle for the two wave fronts of the elastic wave fieldSubject C
259 citations
TL;DR: In this paper, a series of perception experiments were conducted to determine if a brief stimulus in which only the spectral information at onset is preserved provides sufficient cues for identification of place of articulation across vowel contexts, and if it does, to define further the nature and size of the spectral window.
Abstract: In this series of perception experiments, we have attempted (a) to determine if a brief stimulus in which only the spectral information at onset is preserved provides sufficient cues for identification of place of articulation across vowel contexts, and (b) if it does, to define further the nature and size of the spectral window. Subjects were randomly presented with synthetically produced stimuli consisting of a 5‐ or 10‐msec noise burst followed by a brief voiced interval containing three formant transitions with onset and offset characteristics appropriate to the consonants [b, d, g] in the environment of the vowels [a, i, u], as well as stimuli with steady second‐ and third‐formant transitions. The length of the voiced interval was systematically varied from 40 to 5 msec. The results indicate that an onset spectrum consisting of the burst plus the initial 5 or 10 msec of voicing provide sufficient cues for the identification of the stop consonant, and that vocalic information can be reliably derived from these brief stimuli containing only one or two glottal pulses. [Research approved by an NIH grant.]
252 citations
TL;DR: It is concluded that categorical perception of sounds is not unique to speech and suggested that it may be a general property of sensory behavior.
Abstract: The onset of a noise [0.9–2.1 kHz, 55 dB SPL (A weighted)] preceded that of a buzz [100 Hz, 0.5–3.0 kHz, 70 db SPL (A weighted), 500 msec] by −10 to +80 msec and both terminated simultaneously. Eight adults discriminated among noise‐lead times in an oddity task. In separate sessions, they labeled singly presented stimuli with either of the two responses: ’’no noise’’ or ’’noise.’’ The results are highly similar to those reported for the categorical perception of synthetic plosive consonants differing in voice‐onset time. On the average, discrimination was best across a noise‐lead‐time boundary of about 16 msec, where labeling also shifted abruptly. These results and those of categorical perception, generally, are interpreted in terms of Weber’s law as applied to a single component within a stimulus complex. It is concluded that categorical perception of sounds is not unique to speech and suggested that it may be a general property of sensory behavior.Subject Classification: [43]65.75; [43]70.30.
TL;DR: In many conditions of listening, sensitivity to interaural time differences at high frequencies compares favorably with sensitivity at low frequencies—good performace requires only tens of microseconds of interaurally time delay.
Abstract: Sensitivity to interaural time differences at high frequencies is demonstrated in a number of experiments. Two types of waveforms are used—bands of noise and two‐tone complexes. Variables studied are rate and depth of fluctuation of the envelope, overall intensity, and additivity of interaural time information across frequency regions. In many conditions of listening, sensitivity to interaural time differences at high frequencies compares favorably with sensitivity at low frequencies—good performace requires only tens of microseconds of interaural time delay.Subject Classification: [43]65.62, [43]65.68.
TL;DR: Cochlear microphonic and summating potential recordings were obtained from preparations where only either inner hair cells or outer hair cells could have contributed to the potentials, and a comparison suggests that outerhair cells do produce the preponderance of receptor potentials.
Abstract: 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.
TL;DR: When trained to the voice of a particular speaker, the decoder recognized seven‐digit telephone numbers correctly 96% of the time, with a better than 99% per‐digit accuracy.
Abstract: Continuous speech was treated as if produced by a finite‐state machine making a transition every centisecond. The observable output from state transitions was considered to be a power spectrum—a probabilistic function of the target state of each transition. Using this model, observed sequences of power spectra from real speech were decoded as sequences of acoustic states by means of the Viterbi trellis algorithm. The finite‐state machine used as a representation of the speech source was composed of machines representing words, combined according to a “language model.” When trained to the voice of a particular speaker, the decoder recognized seven‐digit telephone numbers correctly 96% of the time, with a better than 99% per‐digit accuracy. Results for other tests of the system, including syllable and phoneme recognition, will also be given.
TL;DR: With a tone‐on‐tone masking procedure the compound action potential (AP), elicited by brief tone bursts of set frequency and intensity, was decreased by a constant fraction, and the frequency–intensity pairs formed by the masker generate the AP tuning curve.
Abstract: With a tone‐on‐tone masking procedure the compound action potential (AP), elicited by brief tone bursts of set frequency and intensity, was decreased by a constant fraction. The frequency–intensity pairs formed by the masker that yield this decrease generate the AP tuning curve. It is demonstrated that such tuning curves are very similar to both psychophysical tuning curves and single VIIIth‐nerve‐fiber tuning curves. Changes in the properties of these curves are described as functions of stimulus frequency and level, mode of masking (simultaneous and forward), and parameters of the masker.Subject Classification: [43]65.40, [43]65.42, [43]65.58.
TL;DR: In this article, Huygen's principle is invoked to describe the scattering of waves by an obstacle of arbitrary shape immersed in an elastic medium, and conservation laws are discussed with respect to the divergence and curl of the displacement.
Abstract: Upon invoking Huygen’s principle, matrix equations are obtained describing the scattering of waves by an obstacle of arbitrary shape immersed in an elastic medium. New relations are found connecting surface tractions with the divergence and curl of the displacement, and conservation laws are discussed. When mode conversion effects are arbitrarily suppressed by resetting appropriate matrix elements to zero, the equations reduce to a simultaneous description of acoustic and electromagnetic scattering by the obstacle at hand. Unification with acoustic/electromagnetics should provide useful guidelines in elasticity. Approximate numerical equality is shown to exist between certain of the scattering coefficients for hard and soft spheres. For penetrable spheres, explicit analytical results are found for the first time.Subject Classification: [43]20.15, [43]20.30.
TL;DR: It is conjectured that the design of the cochlea is influenced by two conflicting requirements: (1) the coChlea should act as a precise frequency analyzer and (2) waves propagating along the basilar membrane should be transmitted without reflections.
Abstract: It is conjectured that the design of the cochlea is influenced by two conflicting requirements: (1) the cochlea should act as a precise frequency analyzer and (2) waves propagating along the basilar membrane should be transmitted without reflections. Accurate frequency analysis is possible only if the mechanical properties of the cochlea change rapidly with distance along the basilar membrane. Reflections of waves traveling on the basilar membrane will be negligible, however, only if these same mechanical properties change slowly. A compromise between these two requirements is possible if a loss constant δ related to the sharpness of response of the basilar membrane to a pure tone is related to the number N of wavelengths of the wave on the basilar membrane [N/(δ)1/2?1]. Furthermore, if sizable changes in the displacement occur only over distances larger than the width of a hair cell, then δ must be larger than the ratio of the width w of a hair cell to the distance d along the basilar membrane over which...
TL;DR: In this article, it is suggested that simple but accurate predictions of noise levels can be made by assuming that an excess attenuation due to finite ground impedance would always exist in a certain shadow region near the ground.
Abstract: There is an extensive body of theory, and some laboratory measurements, of sound propagation over a surface of finite impedance. There are also reliable measurements of outdoor sound propagation in near‐horizontal directions over the ground. In an attempt to relate these more closely, we have made carefully controlled measurements at ranges from 1 to 1000 ft, in most cases over grass‐covered flat surfaces, to demonstrate the several phenomena that are involved. These phenomena depend on, and conversely provide a means of estimating, the values of ground impedance for waves at near‐grazing angles of incidence. Such values obtained for grass‐covered surfaces are in reasonable agreement with each other and with values obtained by conventional means at other angles of incidence. It is suggested that simple but accurate predictions of noise levels can be made by assuming that an excess attenuation due to finite ground impedance would always exist in a certain shadow region near the ground. This shadow region i...
TL;DR: A reflectionless metal tube which can act as a pseudoinfinite termination of the vocal tract was used to collect glottal volume-velocity waveforms produced by 10 male and female adult subjects, indicating a wide variation of theglottal waveform shape, its rms intensity and fundamental frequency, phase spectrum, and intensity spectrum.
Abstract: A reflectionless metal tube which can act as a pseudoinfinite termination of the vocal tract was used to collect glottal volume‐velocity waveforms produced by 10 male and female adult subjects From each subject, glottal volume‐velocity samples were collected of normal, loud, and soft voice; falsetto and creaky voice; monosyllables with rising and falling intonation; and three‐syllable utterances containing primary lexical stress on one of the three syllables Analysis of the data indicates a wide variation of the glottal waveform shape, its rms intensity and fundamental frequency, phase spectrum, and intensity spectrum It is observed that as the fundamental frequency changes over time, the glottal source varies in one of two different ways In one type of change, the harmonic relations in the glottal spectrum become steeper as fundamental frequency rises In a different type of glottal‐wave change, relations between harmonics tend to remain the same despite a change in the fundamental frequency; the source spectrum in this case is simply shifted along the frequency and amplitude axes as a function of fundamental frequency To account for these variations in the glottal source, at least three factors must be known: the sex of the speaker, the voice register in which he phonates, and the linguistic context in which the phonation occurs
TL;DR: Using a nonlinear regression program, the standard deviations of four of the auditory localization cues are estimated, allowing objective comparison of their relative accuracy.
Abstract: A mathematical model based on statistical decision theory has been devised to represent the human auditory localization task. The known localization cues have been represented as Gaussian random variables, so that their interaction in a given experiment can be analyzed (and predicted) along the lines of classical detection/estimation theory. We have applied this technique to most of the horizontal and vertical localization experiments reported in the literature during the past ten years, encompassing over 200 subjects and 20 000 trials. Using a nonlinear regression program we have been able to estimate the standard deviations of four of the auditory localization cues, allowing objective comparison of their relative accuracy. The resulting model provides a relatively good fit to the published results on 40 localization experiments.Subject Classification: [43]65.62, [43]65.58, [43]65.35.
TL;DR: Fractional response is a quantitative measure of the amount of suppression produced by a suppressor tone and a number of qualitative differences were found in the dependence of fractional response for f2≳CF and f2
Abstract: Average discharge rate of single auditory‐nerve fibers in cats was measured in response to one‐ and two‐tone stimuli. One component (the ’’suppressor tone’’) of each two‐tone stimulus was at a frequency (f2) which produced two‐tone suppression at some stimulus levels. The other component (excitor tone) produced an increase in rate above the spontaneous rate when presented alone. Fractional response was defined as the driven rate to the two‐tone stimulus divided by the driven rate to the excitor alone. Fractional response is thus a quantitative measure of the amount of suppression produced by a suppressor tone. A number of qualitative differences were found in the dependence of fractional response for f2≳CF and f2
TL;DR: In this article, the second in a series of articles in human listeners' abilities to discriminate between word-length tonal sequences, or "patterns", has been reported that frequency resolution, by highly trained listeners, is four to five times more accurate for high frequency, late occurring components of such sequences than for low frequency early components.
Abstract: This is the second in a series of articles in human listeners’ abilities to discriminate between word‐length tonal sequences, or ’’patterns.’’ The first article reported that frequency resolution, by highly trained listeners, is four to five times more accurate for high‐frequency, late‐occurring components of such sequences than for low−frequency early components [Watson, Kelly, and Benbasset, J. Acoust. Soc. Am. 57, 1175–1185 (l975)]. These effects, which are similar to described as ’’recognition masking’’ or ’’informational masking’’ by other authors, have now been shown to be strongly dependent on the degree of trial‐to‐trial stimulus uncertainty of the psychophysical procedure in which they are measured. When stimulus uncertainty is reduced to its psychophysical minimum, frequency resolution for any component of a tonal sequence is only slightly less accurate than for isolated tones. Previous reports of recognition masking this may reflect limitations imposed by those more dynamic parts of the sensory...
TL;DR: In this article, the equations of three-dimensional linear piezoelectricity were applied in the analysis of trapped energy resonators with rectangular electrodes vibrating in coupled thickness shear and thickness twist in the vicinity of the fundmantal and odd overtone thickness-shear frequencies.
Abstract: The equations of three‐dimensional linear piezoelectricity are applied in the analysis of trapped‐energy resonators with rectangular electrodes vibrating in coupled thickness shear and thickness twist in the vicinity of the fundmantal and odd overtone thickness‐shear frequencies. Closed form asymptotic expressions for the frequency wave‐number dispersion relations for the fundamental and odd overtone coupled thickness‐shear and thickness‐twist waves near cutoff are obtained for both the electroded and unelectroded regions of the trapped‐energy resonator. The influence of piezoelectric stiffening, electrode mass loading, and electrical shorting is included in the analysis. Simple approximate boundary conditions at a junction between an electroded and unelectroded region of the plate are obtained in a manner exhibiting the natural limitations inherent in the approximation. In order that these boundary conditions can be satisfied at each such junction, in the adjacent regions the wave numbers in the direction of the junction line are assumed to be the same. The boundary conditions to be satisfied at the junctions between the unelectroded corner region and the unelectroded regions adjacent to the electroded region are obtained from an extended version of the variational principle of linear piezoelectricity. These latter conditions result in the form of the solution in the corner region. One result of the foregoing analysis is the determination of a two‐dimensional condition which is a generalization of Bechmann’s number in one dimension. The above‐mentioned dispersion relations and edge conditions are applied in the analysis of the steady‐state vibrations of a trapped‐energy resonator and a lumped parameter representation of the admittance, which is valid in the vicinity of a resonance, is obtained.Subject Classification: [43]40.24; [43]85.52, [43]85.32.
TL;DR: The auditory sensitivity of the (Sprague-Dawley strain) albino rat was determined by the conditioned suppression technique and there was no evidence for a highly specialized tuning of the audiogram to tones in the 30-40 kHz region.
Abstract: Auditory sensitivity of the albino rat was determined using the conditioned suppression of licking technique. The rat was found to have a range of sensitivity to pure tones from 250 Hz to 80 kHz at 70 dB SPL. The point of maximum sensitivity was 8 kHz closely rivaled by higher frequencies up to 38 kHz. Withing this band, tones were detectable at sound pressures from 2–7 dB SPL. For frequencies above 38‐kHz sensitivity rapidly decreased at a rate of about 50 dB per octave. For frequencies below 8‐kHz sensitivity decreased at a rate of about 20 dB per octave. The audiogram supports previous evidence of good hearing around 32–38 kHz [G. Gourevitch and M. H. Hack, J. Comp. Physiol. Psych. 62, 289–291 (1966)], but does not support the idea that the albino rat's hearing is narrowly tuned to this range. Thus, the sensitivity of the albino rat to these frequencies reflects the broadly tuned high frequency hearing which is generally quite good in small mammals, rather than representing a specialized feature of its auditory system. [Supported by grants from NRC and NIH.]
TL;DR: In this article, the thermal conduction losses of the gas in the cavitation bubble during its rapid collapse were considered, and an expression was found for the final temperature of a gas.
Abstract: The sonoluminescence from 17 different gases dissolved in water was measured. The results show an inverse relation with the thermal conductivity of the gas. The thermal conduction losses of the gas in the cavitation bubble during its rapid collapse are considered, and an expression found for the final temperature of the gas. The sonoluminescence results for the five rare gases studied agreed with this theory.Subject Classification: [43]35.68, [43]35.32.
TL;DR: In this paper, it was pointed out by Brillouin that what we call radiation pressure is not a pressure at all, but a diagonal tensor, all the diagonal terms of which are not identical.
Abstract: The acoustic radiation pressure has found practical application in recent years in instruments measuring sound intensity and in experiments on acoustic levitation. The concept of radiation pressure has, however, long fascinated both optical and acoustical physicists. The history of light radiation pressure goes back more than 200 years to Leonhard Euler, while the concept of acoustic radiation pressure dates from the time and work of Rayleigh. It was pointed out by Brillouin that what we call radiation pressure is not a pressure at all, but a diagonal tensor, all the diagonal terms of which are not identical. The size of the effect is small, and the values obtained for the radiation pressure are very sensitive to boundary conditions and to the approximations that must necessarily be employed. In addition, although the phenomenon is primarily one of nonlinear acoustics, it can be observed down to the lowest sound intensities under certain conditions. Thus, the Rayleigh radiation pressure vanishes for the linear case, but the usually measured Langevin pressure does not. It might be said that radiation pressure is a phenomenon that the observer thinks he understands—for short intervals, and only every now and then.
TL;DR: In this paper, Biot's theory was employed in the study of wave motions in fluid-saturated porous rocks and the equations were solved using a Laplace transformation, and it was shown that the measured waves are in fact the fast waves.
Abstract: 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.
TL;DR: In this article, the backscattering frequency responses for euphausiids and copepods were predicted using a fluid-sphere model and measured physical properties for the zooplankters.
Abstract: The backscattering frequency responses for euphausiids and copepods are predicted using a fluid‐sphere model and measured physical properties for the zooplankters. The fluid‐sphere model is also compared with the resonant gas bubble equation.
TL;DR: In electrocochocholegraphy, compound action potentials (AP) are recorded from the human promontory and the guinea pig round window to derive a response area for a given type of stimulus, e.g., tone bursts.
Abstract: In electrococholegraphy, compound action potentials (AP) are recorded from the human promontory and the guinea pig round window. High‐pass noise masking and subtraction of AP responses at various high‐pass cutoff frequencies give the narrow‐band contributions to the whole nerve AP. Although the narrow‐band contributions recorded from human and guinea pig ears differ essentially, this narrow‐band concept makes it possible to derive a response area for a given type of stimulus, e.g., tone bursts. Within the response area, any combination of stimulus intensity and site on the cochlear partition evokes a detectable narrow‐band response contributing to the whole‐nerve AP. The main part of this contribution shifts basally the higher the stimulus intensity. Latency differences between responses from the various narrow bands are used to calcuate the traveling‐wave velocity for the human cochlea, which ranges from about 20 m/sec at 10 kHz to 1 m/sec at 500 Hz. The amplitude and width of the narrow‐band responses a...
TL;DR: Measurements of the transient response of the basilar membrane were conducted using the Mossbauer effect on 33 squirrel monkeys using an experimental preparation identical to that of Rhode ( 1971), showing consistency with nonlinearity reported using steady‐state measurement methods.
Abstract: Measurements of the transient response of the basilar membrane were conducted using the Mossbauer effect on 33 squirrel monkeys using an experimental preparation identical to that of Rhode (1971). The stimuli were acoustic clicks 150 μsec in duration repeated 100 000–400 000 times. The amplitude of the click was varied and the responses of the malleus and of the basilar membrane at a point in the basal turn were measured. The basilar membrane’s click response is oscillatory, with a period near that of the characteristic frequency. The first few response peaks behave almost linearly with stimulus intensity, while the later peaks exhibit a pronounced nonlinearity. This behavior is shown to be consistent with the nonlinearity reported using steady‐state measurement methods (Rhode, 1971). The transient response observed in some of the preparations was very lightly damped; however, a wide range in the damping of the responses was found in the different animals. A progressive increase in the rate of decay of th...