bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Skin Perception of Traveling Waves Similar to Those on the Cochlea
Authors: v. Békésy G. 
Published: September 2005

The membrane of a dimensional model of the mechanical parts of the human cochlea (30 cm in over-all length) showed under stroboscopic illumination traveling waves similar to those on the cochlea and a flat maximum of vibration which shifted from one end of the model to the other when the frequency was increased from 40 cps to 160 cps. When the skin of the arm is placed in close contact with the membrane, the vibrations are localized in a quite narrow section of the membrane, so that any change in frequency can be detected by a change in the locus of stimulation. The localization is as sharply defined for pure tone pulses of the length of two sine waves as for continuous tones. The localization of pure tones along the membrane is practically instantaneous.
The sharp localization in spite of the flat distribution of vibrations along the membrane is produced by the inhibitory effects of the skin. Their influence and magnitude are demonstrated by various experiments.
Some basic relations between nerve density on the cortex, threshold, and loudness increase on the skin are pointed out in the hope that they will later enable us to determine the differences between the organ of Corti and the simple skin membrane. This would be helpful to our understanding of the nature and function of the complicated structure of the organ of Corti. On the whole, in the observation of pitch of pure tones, the simple skin-model is as useful as the organ of Corti itself. The differences become apparent only in the observation of more complex sounds.
Two models were used to investigate the possibility of obtaining effects similar to the stereophonic effects in hearing.
Relation between Loudness and Duration of Tonal Pulses. III. Response in Cases of Abnormal Loudness Function
Authors: Miskolczy-Fodor F. 
Published: September 2005

The previously determined relation between time-threshold and loudness is investigated in cases of abnormal loudness response.
General principles concerning the nature of the altered function are established in pathologic cases with complete recruitment by time-threshold measurement and by binaural loudness matching with the following results: (1) at a constant level above threshold, the hearing loss in decibels is related to the logarithm of the pathologic degree of loudness increment, as determined by L/I values; (2) for a given hearing loss, the L/I value of the loudness-increment degree decreases linearly with the logarithmic increase of the level above threshold; (3) the graphic results of time-threshold determination appear directly continuous with those of loudness matching.
Present findings extend the validity of previously determined loudness-duration relations to abnormal loudness responses. Experimentally induced abnormal loudness response under conditions of masking confirms the results.
In cases of mixed impairment, with incomplete recruitment, the receptive component of hearing loss can be determined in decibels from the measured degree of loudness increment. The results of such determinations are similar to those obtained by bone-conduction measurements.
The significance of time-threshold determinations and the limitations in their practical applicability for loudness measurements are discussed.
Effects of Training on Listeners in Intelligibility Studies
Authors: Moser Henry M. , Dreher John J. 
Published: September 2005

Six hundred English monosyllables formed by successive agglutination of initial consonants were presented in high noise to twelve subjects skilled in listening in noise but uninformed as to the words. Alternate training and testing sessions were conducted at weekly intervals following this initial test and differential responses to the words were plotted. Results indicate that corect response in inversely proportional to the number of speech sounds in the monosyllable, with one exception: the two sound monosyllable is superior to all other lengths when subjects have had even one chance to hear words read aloud. Responses grow progressively better, apparently becoming asymptotic to a ceiling value determined by the S/N ratio, at the same time preserving the same order of difference as established by the naive group.
PB lists now in current use in audiology are analyzed according to phonetic length and a method for correcting internal inconsistencies lists is proposed.
Amount and kind of listener training is seen as a primary variable in intelligibility testing.
Mutual Acoustic Impedance between Radiators in an Infinite Rigid Plane
Authors: Pritchard R. L. 
Published: September 2005

A series solution has been obtained for the mutual acoustic impedance between two identical circular disks vibrating in an infinite plane. Under simplifying conditions, the resistive and reactive components of the mutual impedance each can be expressed in terms of a simple trigonometric function. The problem was formulated in terms of Bouwkamp's method of integrating over real and complex angles the square of the directional characteristic (relative sound pressure at a large fixed distance) to yield the total radiation impedance. Integrals involved here are similar to a type previously evaluated by Stenzel and may be expressed in terms of a double series containing Bessel functions of integral and half-integral order. Numerical values of the mutual acoustic impedance obtained by this method for two rigid disks are in good agreement with values obtained by Klapman by direct integration of the pressure at the surfaces of the disks. The acoustic self impedance and mutual impedance may also be calculated by the same methods for a more general type of circular disk having a prescribed radially symmetric velocity distribution.
To illustrate the applicability of these results, the total acoustic loading upon an array of circular disks is calculated by taking into account the mutual acoustic impedance between the disks comprising the array. Numerical results are given for a circular array of seven identical disks having a radius small relative to a wavelength and vibrating uniformly in a common, rigid plane.
Response of Strings to Random Noise Fields
Authors: Lyon Richard H. 
Published: September 2005

A formulism for predicting the motion of continuous systems excited by random noise fields is applied to the special case of a one-dimensional string. Several examples are attacked: (1) Brownian motion of finite strings, (2) response to a spatially stepped-temporally delayed noise field, (3) response of finite ribbon to moving, random pressure fluctuations, (4) response of an infinite ribbon to moving, random pressure fluctuations. Cases (2) and (3) are investigated experimentally, the latter by using flowing turbulence.
In case (2) appears the interesting phenomenon of the capability of the string “remembering” or “forgetting” a signal which it received in the past. The larger the damping of the string, the sooner it will forget a previous signal. In cases (3) and (4) a coincidence effect appears between the flow velocity of the forcing field and the velocity of waves on the ribbon. Here again, the phenomenon of forgetting appears and sharply determines the magnitude of any coincidence effect which may appear.
Effects of Two Message-Storage Schemes upon Communications within a Small Problem-Solving Group
Authors: Bertsch W. F. , Webster J. C. , Klumpp R. G. , Thompson P. O. 
Published: September 2005

Each of four men spoke messages at predetermined times to a central operator over an independent communication channel. Each message consisted of an address, station identification, and three pieces of information. The operator identified relevant messages by the address and/or station identification and transcribed the information symbolically onto a plotting board. Message density varied from the overlapping of two or three messages to gaps of 20 seconds between single messages.
The purpose of the study was to evaluate two message storage schemes. In one scheme the messages could be delayed by 9 seconds at the option of the operator (fixed-delay), in the other every message was stored until the operator called for it (variable-delay). The fixed-delay and variable-delay message storage schemes were compared to a no-help (no-delay) condition, where the operator had no control over the sequence of messages.
The criteria used to evaluate the storage schemes were (1) the number of message repeats requested by the operator (and the associated time delays) and (2) the number of messages incorrectly transcribed (or not transcribed). The variable-delay storage scheme was superior for all criteria, that is, fewer repeats were requested and fewer errors were made. The fixed-delay scheme was difficult to use and was not always superior to the no-help case.
Intelligibility of UHF and VHF Transmissions at Fifteen Representative Air Traffic Control Towers
Authors: Beitscher H. R. , Webster J. C. 
Published: September 2005

A comparison of the intelligibility of UHF and VHF communications was made between “plane to tower” and “tower to plane” at fifteen control towers. A specially equipped plane was flown in a circle with a 20-mi radius for these tests. Voice Communication Laboratory multiple-choice word lists were read by two talkers, one in the plane and the other in the tower. These messages were recorded on tape in both places.
Five subjects listened to these recordings in the laboratory, and their responses were scored for accuracy against the original word lists. The percentage of words heard correctly from tower to plane varied from 90% to 38% with an average of 73.7% and was much higher than the corresponding percentage from plane to tower of 63% to 3% with an average of 44.4%. There was very little difference between the intelligibility of VHF and UHF. In general, those towers that had high plane-to-tower scores also had high tower-to-plane scores: the correlation among towers between hearing and being heard was fairly high.
Reflection of a Plane Acoustic Wave from a Surface of Nonuniform Impedance
Authors: Heaps H. S. 
Published: September 2005

A theoretical analysis is made of the reflection of a plane wave of sound from a surface whose acoustic impedance is not uniform. The sound pressure received at a distant point consists of a specularly reflected wave plus scattered radiation. The magnitude of the specularly reflected wave is independent of wavelength and depends upon the impedance of the portion of the surface which may be viewed at the specular angle from the receiver. If the impedance differs only slightly from a constant value the directivity pattern of the scattered radiation is determined by the product of three factors.
The condition for the scattered radiation to obey Lambert's cosine law is that the reflecting surface is one of approximately zero pressure and that there is no correlation in the impedance irregularities. The condition for perfectly diffuse scattered radiation is that the surface behave as approximately rigid with no correlation in the impedance irregularities. In the case of a surface whose impedance irregularities have a slow statistical variation with position the scattered radiation is confined to a beam whose axis lies along the direction of specular reflection but the energy within the beam is not necessarily closely confined to the specular angle.
Procedure for Calculating Loudness: Mark VI
Authors: Stevens S. S. 
Published: September 2005

In order to improve the procedure for calculating the loudness of a complex sound, two changes have been made. (1) The equal loudness contours for bands of noise in a diffuse field have been approximated by straight lines in a log-log plot. (2) The spacing of the contours have been altered to reflect the nonlinear growth that takes place in the loudness level of bands of noise when their width exceeds the critical bandwidth. The basic formula for the addition of loudness across frequency remains the same: the total loudness St is given by St = Sm + F(Σ S − Sm), where Sm is the loudest band and F has the values 0.3, 0.2, and 0.15 for octave, half-octave, and third-octave bands.
The revised procedure has the advantages that it can be described more easily and it agrees better with the available measurements on loudness level.
Wall Pressure Fluctuations in a Turbulent Boundary Layer
Authors: Willmarth William W. 
Published: September 2005

When a turbulent boundary layer is produced by air flow past a solid surface, the turbulence in the boundary layer can generate a sound field in the free stream and will also induce fluctuating loads on the solid surface. If the surface is flexible, this motion will generate an additional sound field on both sides of the surface.
In an initial investigation of the latter form of sound generation, suitable equipment has been developed to measure the fluctuating wall pressure in the turbulent boundary layer. The equipment includes a specially designed low noise and turbulence level wind tunnel and a small barium titanate transducer and preamplifier combination for frequencies up to 50 kc. The transducer and preamplifier may be useful for other applications.
Using this equipment, some of the properties of the wall pressure fluctuations in a turbulent boundary layer have been measured. It was found that the spectrum of the wall pressure fluctuations extends to 50 kc and that the root-mean-square wall pressure was a constant portion (0.0035) of the free stream dynamic pressure for 0.2 &lt;M &lt;0.8 and 1.5×106&lt;Re&lt;20×105. A few typical spectra are given for different values of the Reynolds number and Math number.
Determination of the Normal Hearing Reference Zero
Authors: Glorig Aram , Quiggle Robert , Wheeler D. E. , Grings William 
Published: September 2005

The present American normal hearing reference zero is considered by many investigators to be too high. The data from two recent studies on normal hearing provide a possible explanation. One of these studies, which was a survey type study, confirmed the present reference zero. The second study, a laboratory type study, confirmed the results of other laboratory studies that had led to the opinion that the present zero is too high.
In our opinion, the difference between the results of these two studies and various other studies of the auditory threshold are due to the inherent difference in experimental technique in laboratory and survey type studies. In establishing normal hearing reference zero, it is no longer a question of resolving differences in various studies but a question of whether survey or laboratory data will be used.
Contour Vibrations of Isotropic Circular Plates
Authors: Onoe Morio 
Published: September 2005

A mathematical analysis has been done according to Love's theory. The results are: (a) The coefficients of the dilatation and the rotation are equal in amount regardless of Poisson's ratio only for the modes whose circumferential order is one. (b) The first mode whose order is two has the lowest natural frequency. This mode is practically equivoluminal, while the second mode is dilatational. (c) Locations of nodes are considered. Circular nodal lines can exist only for the radial and the tangential modes. (d) Frequencies and displacements of the most important modes are calculated.
Applying the above results to barium titanate vibrators, we find that only the radial modes can be excited with full electrodes and the compound modes with split or partial electrodes, while the tangential modes can never be excited. Such an excitation of compound modes provides a convenient means for measuring Poisson's ratio of the material. Equivalent series inductances of the radial modes are calculated.
Vibrations of thick circular plates are also considered. It is shown that vibrations of certain compound modes which are practically equivoluminal can be approximated by the rotation only. Comparisons between these solutions and the above results are made to reveal that the accuracy of approximation is satisfactory.
Acoustic Radiation Pressure
Authors: Westervelt Peter J. 
Published: September 2005

An expression obtained (1951) by the author for the radiation force on a scattering obstacle with arbitrary normal impedance is now shown to be valid for any scattering obstacle. The derivation of the final expression for the force in terms of the asymptotic scattering function for the obstacle in the field of an incident plane wave is accomplished by taking into account the interaction of the incident wave with the scattered wave. Thus the former assumption of a perfectly collimated beam (1951) is avoided by considering the incident plane wave to be of infinite extent. The result for the force in the direction of the incident wave is F∥ = c0−1{power scattered+power absorbed−∫Γs cosθdA} where c0 is the velocity of sound, Γs is the magnitude of the mean scattered intensity, θ is the angle formed between the incident and scattered waves. This is the same result as that obtained in 1951.
The expression given in 1951 for the force perpendicular to the incident wave is correct only for an object which scatters in a restricted way. The correct general expression for the perpendicular component of the force is F⊥ = − c0−1∫Γs cosβdA in which β is the angle formed between F⊥ and Γs.
Representation of the Field of an Acoustic Source as a Series of Multipole Fields
Authors: Oestreicher Hans L. 
Published: September 2005

A representation of the field of a sound source of arbitrary shape and size as a series of multipole fields of increasing order is derived. This series is convergent for sources of any size if the surface is sufficiently regular, but its main advantage is for sources small compared to the wavelength. In this case the source has, in general, the directivity pattern of a multipole, the order and strength of which can be determined from the formula.
Although the representation is not unique, certain coefficients have physical significance. The presently used definition of “strength of a sound source” is discussed and a modified definition suggested.
Piezoresistive Semiconductor Microphone
Authors: Burns Fred P. 
Published: September 2005

A microphone using the piezoresistive effect of n-type germanium has been designed and constructed with a cantilever beam arrangement. Frequency response curves were taken in a sound field of 10 microbars with the microphone in a bridge type circuit and biased with 9 and 18 milliamperes.
The microphone produces 10−11 watt in the flat low frequency range and peaks to 10−9 watt at a resonance at 2570 cps with a total bias of 18 ma in a bridge type circuit. Other designs of transducers and different types of semiconductor material are discussed. The performance of a germanium rod microphone is compared with a standard carbon button transmitter.
Downward Spread of Masking
Authors: Spieth Walter 
Published: September 2005

Pulsed pure-tone audiograms were obtained in quiet and in the presence of narrow bands of noise centered at 500, 1000, 2000, and 4000 cps and at several levels. The masking produced at lower frequencies was of particular interest: The bands of noise at about 75 db/cy SPL produced from 12 to 24 db of masking at 100 cps and from 25 to 40 db of masking at frequencies between about 200 cps and the lower effective limit of the band of noise. This phenomenon contrasts with the fact (briefly reaffirmed in this paper) that a single pure tone of comparable frequency and intensity does not produce appreciable masking at these lower frequencies.
It is hypothesized that a band of noise is functionally somewhat equivalent to a bunch of pure tones which when passed through a nonlinear transducer (the ear), produce aural difference tones which elevate the threshold for signals of lower frequency, while a single tone masker would not have this effect. It was found that two pure tones at a spectrum level and at frequencies comparable to the bands of noise do produce aural difference tones (as measured by best beats) of a level which correspond well with the level of lower frequency masking effects in question.
Effects of Acoustical Waves on the Annealing of Steels
Authors: Fairbanks H. V. , Dewez F. J. 
Published: September 2005

The object of this investigation was to determine the effect of ultrasonic energy on 0.07 and 1.05% carbon steels during transformation from austenite to ferrite under controlled cooling. The ultrasonic energy was produced by means of a bowl-shaped crystal of barium titanate and was coupled to the steel samples through distilled water. Ultrasonic frequencies of 400 and 1000 kc were used.
It was found that the ultrasonic treated samples of 0.07% carbon hypo-eutectoid steel had finer grain size and greater hardness than the reference samples which had undergone the same heat-treating cycle but with no ultrasonic treatment. When either the intensity or the frequency of the ultrasonic energy was increased, the grain size was further decreased.
For the 1.05% carbon hyper-eutectoid, it was found that the lamellar layers of ferrite and iron carbide making up the pearlite crystals were definitely thicker in the ultrasonic treated samples than in the untreated ones. Hardness tests made on the pearlite crystals substantiated the above results.
On the Propagation of Ultrasonic Waves of Finite Amplitude in Liquids
Authors: Krassilnikov V. A. , Shklovskaya-Kordy V. V. , Zarembo L. K. 
Published: September 2005

The dependence of the ultrasonic absorption coefficient on the intensity was measured indifferent liquids (water, ethyl and methyl ethers, toluene, transformer oil, and glycerine) by means of the thermal method (thermocouples). The measurements were made at 1.5 Mc/sec with intensities of 0.3–9 w/cm2. There was found a considerable increase of nearly two orders of magnitude in the absorption. Measurement at higher static pressures, up to 15 kg/cm2, gives results which coincide, within the range of error, with the results of the measurements at atmospheric pressure, suggesting that the influence of cavitation is small.
Direct experimental observation of the harmonics in a traveling wave of finite amplitude was accomplished. The receivers were quartz plates with their fundamental frequencies equal to the frequencies of the harmonics; to remove standing waves between the receiver and the transducer, an acoustic filter was used, consisting of a thin plate “transparent” for the appropriate harmonic and opaque for the fundamental at a certain angle. Absolute measurement of the harmonic intensity was obtained by a radiometer which was placed behind the acoustic filter.
Localization of High-Frequency Tones
Authors: Feddersen W. E. , Sandel T. T. , Teas D. C. , Jeffress L. A. 
Published: September 2005

In an earlier study, [Sandel, Teas, Fedderson, and Jeffress, J. Acoust. Soc. Am. 27, 842 (1955)] the writers attempted to correlate interaural intensity and time differences with the subject's localization response. The present paper is an extension of that work. It includes physical measurements of interaural time differences and intensity differences, and attempts to relate these differences to the localization response at a variety of frequencies. The stimuli to be localized were provided through earphones, and the subject was required to match the position (in his head) of a noise and a tone. The noise to one ear was delayed, and the tone presented with no time or phase difference. The subject adjusted the interaural level of the tone until it and the noise appeared to be in the same place. The two were presented alternately by means of a gate having a 150-msec rise and decay time.
Data from the localization judgments were then compared with the findings from the acoustical measurements of time and intensity. Several systematic trends were found and compared with results of the previous study.