bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropy of Polarized Polycrystalline Barium Titanate
Authors: Moseley Donald S.
Published: September 2005

Square bars of polycrystalline barium titanate ceramic have been prepolarized and their lowest longitudinal resonance excited piezoelectrically on remanent polarization. Bars were prepared as twins in every way, except that one twin was electroded on its ends, the other on a pair of opposite sides. The first polarization applied was that minimum (800 v/cm for 30 minutes at 27°C) which fixed any, electromechanical activity as detected by a sensitive ac bridge, and this was taken to approximate the unpolarized, isotropic state (s11=s33). Different pairs were then given different large scale polarizations (2.5, 5.0, and 10 kv/cm cooled from above the Curie point) and changes noted. All resonant frequencies rose with time, the decay constant being between 0.01 and 0.02 hr−1, and the total change being 1 to 112% for “Ceramic A” (barium titanate), and 12% for “Ceramic B” (barium calcium titanate). For both materials the isotropic compliance was definitely much closer to s33E than to s33D, and averaged closer to s11E than to s11D. The ratios s33:s11 were 0.83 and 0.87 at constant D and 1.04, and 1.05 at constant E for the two materials after 10 kv/cm. Anisotropy varied somewhat with polarizing field strength.
Theory of Continuous-Tone Reverberation
Authors: Klotzbaugh G. A.
Published: September 2005

The shape of the reverberation curve described in the previous paper can be explained if the scatterers in water are assumed to be in motion. The reverberation is assumed to arise from a surface layer and from the main volume of the water. Formulas are given for the two components of reverberation. As an alternative, reverberation may be described in terms of general fluctuations in propagation conditions.
Analysis of Incorrect Responses to an Unknown Message Set
Authors: Pollack Irwin , Rubenstein Herbert , Decker Louis
Published: September 2005

The incorrect responses of listeners to an unknown message set of 144 words, presented in noise, were analyzed. Attention was focused upon the word-frequency distribution of the incorrect responses and upon the proportion of the incorrect responses that were nonsense responses. Both measures were affected by the speech-to-noise ratio, but were approximately independent of the stimulus-word frequency.
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.
Acoustical Streaming in the Vicinity of a Sphere
Authors: Lane C. A.
Published: September 2005

Recent studies have led to a satisfactory understanding of the details of acoustical streaming in the vicinity of a cylinder. Similar studies have now been completed for a sphere. In general, the steady flow around a sphere and the characteristic parameters are very much like what has been found for the cylinder. An experimental verification of the theory has been attempted by comparing the observed dc boundary-layer thickness with that found from the theory. This is summarized in a curve of δdc/δac vs a/δac, where δdc is the dc boundary-layer thickness, δac is the ac boundary-layer thickness, and a is the radius of the sphere.
Fourier Series for the Finite Amplitude Sound Waveform in a Dissipationless Medium
Authors: Hargrove Logan E.
Published: September 2005

A general expression is derived for the Fourier coefficients describing the change in waveform of an initially sinusoidal plane progressive acoustic wave of finite amplitude in a dissipationless medium. The first four Fourier coefficients are graphically presented for distances up to the discontinuity distance.
Effects of Noise on the Blood-Eosinophil Levels and Adrenals of Mice
Authors: Anthony Adam , Ackerman Eugene
Published: September 2005

Physiological changes are described following exposure of mice to single and intermittent noise stimulation (110 db re 0.0002 dyne/cm2, 10–20 kc) for varying lengths of time. Attention is focused on the degree of adreno-cortical activation as measured by cytological changes in the adrenal gland and fall in the number of circulating eosinophils. Since the observed changes were transient, of short duration and no evidence of systemic pathology could be detected, the noise was described as not harmful. The tendency of certain investigators to regard noise as an injurious, nonspecific stress stimulus without specifying the exact nature of the noise situation does not seem justified.
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.
A Moiré Fringe Analog of Sound Propagation in Shallow Water
Authors: Weston D. E.
Published: September 2005

A moiré fringe analog of the normal modes of sound propagation in shallow water is described, in which interesting patterns are obtained both by direct visual observation and by photographic recording. These are analogs for the profiles of sound pressure as a function of range and depth in the underwater field due to a single-frequency source. Since phase is correctly represented, the interaction patterns due to the presence of considerable numbers of interfering modes may be investigated experimentally. This is important since mathematical analysis becomes difficult when there are more than two modes. There is a discussion of the characteristics of these patterns (including the formation of “loops”) and also of those obtained by A. B. Wood in his sound propagation model experiments.
Duration of Syllable Nuclei in English
Authors: Peterson Gordon E. , Lehiste Ilse
Published: September 2005

This study deals with the influence of preceding and following consonants on the duration of stressed vowels and diphthongs in American English. A set of 1263 CNC words, pronounced in an identical frame by the same speaker, was analyzed spectrographically, and the influences of various classes of consonants on the duration of the nucleus were determined. The residual durational differences are analyzed as intrinsic durational characteristics, associated with each syllable nucleus. The theory is tested with a set of 30 minimal pairs of CNC words, uttered by five different speakers.
Parameter of Nonlinearity in Fluids
Authors: Beyer Robert T.
Published: September 2005

Values of the parameter of nonlinearity for acoustics B/A = (ρ0/c02) (∂2p/∂ρ2)s, are given for all liquids for which experimental data are available. The experimental data indicate that B/A generally increases slowly with temperature. A method of computing B/A directly from finite-amplitude acoustic measurements is also presented.
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.
Resonance Absorption in Solid Cyclohexane
Authors: Rasmussen Robert A.
Published: September 2005

Measured values of the acoustic absorption coefficient for monocrystalline cyclohexane in the range of from 3 to 8 Mc are presented and compared with those predicted by the “resonance” absorption theory proposed by Liebermann.
Viscous Damping of Bubbles
Authors: Gould R. K. , Nyborg W. L.
Published: September 2005

An expression is derived for the spatial distribution of viscous energy losses in the doby of liquid surrounding a vibrating spherical bubble.
Tabular Data of the Velocity and Absorption of High-Frequency Sound in Mammalian Tissues
Authors: Goldman D. E. , Hueter T. F.
Published: September 2005

This report is a condensed presentation of currently available data on the velocity and absorption of high-frequency sound in mammalian tissues.
Determination of the Hearing Thresholds of Naval Recruits in Terms of British and American Standards
Authors: Knight J. J. , Coles R. R. A.
Published: September 2005

A group of 111 naval recruits was examined in order to establish reference hearing level against which to assess the effects of noise exposure in serving men. The pure-tone thresholds were taken in a quiet ordinary room with a commercial audiometer. After exclusion of some subjects for reasons given, the thresholds of the main group of 74 men were analyzed. Precautions taken to insure constancy of performance of the audiometer are described and its calibration was obtained relative to both the appropriate British and American standards. The results of the survey showed good agreement with the British standard as regards the main group and additionally for a group of 15 men selected for minimal exposure to gunfire (less than seven rounds of small-arms fire). A comparison was made with the hearing level of a small group of more experienced listeners when an improvement of about 2.5 db was found. The relation of the work to other hearing surveys and laboratory measurements is discussed.
Theory of Propagation of Elastic Waves in a Fluid-Saturated Porous Solid. II. Higher Frequency Range
Authors: Biot M. A.
Published: September 2005

The theory of propagation of stress waves in a porous elastic solid developed in Part I for the low-frequency range is extended to higher frequencies. The breakdown of Poiseuille flow beyond the critical frequency is discussed for pores of flat and circular shapes. As in Part I the emphasis of the treatment is on cases where fluid and solids are of comparable densities. Dispersion curves for phase and group velocities along with attenuation factors are plotted versus frequency for the rotational and the two dilational waves and for six numerical combinations of the characteristic parameters of the porous systems. Asymptotic behavior at high frequency is also discussed.
On Thermoacoustic Transduction in a Potential Flow
Authors: Mawardi Osman K.
Published: September 2005

The interaction between an acoustic field and a thermal field is worked out for the case of a sound wave propagating down a channel in which the convection of heat occurs in a potential flow. The analysis restricted to inviscid fluids shows that the magnitude of the sound wave is reinforced as it propagates through the thermal field. The extent of this reinforcement is given in the form of an amplification factor which depends on the parameter of the flow and on the frequency of the sound wave.
Changes in Adrenals and Other Organs Following Exposure of Hairless Mice to Intense Sound
Authors: Anthony Adam
Published: September 2005

Systemic effects in hairless mice were studied following local abdominal and scrotal skin exposure to intense air-borne sound. Comparisons were made between effects of moderately high (150 db, 18 kc) and high (160–168 db, 20 kc) levels of sound. Examination of control mice revealed that 10-min daily immobilization for one to three months was sufficiently stressful to cause an hypertrophy of the adrenal cortex and involution of the thymus. Evidence was also obtained which indicated there was an increased adrenal response in immobilized mice which were exposed to moderately high levels of sound for periods of one to three months. It was concluded from these studies that immobilization and sound vibrations on the skin surface can both be considered stressful. The absence of gonadal damage and slight changes in the hemopoietic system indicated these are mild rather than severe stress stimuli. In other experiments where more intense sound was used, the local and systemic response was similar to that known to occur following ordinary skin burns. In these cases heat and not sound was the stressor agent involved.
Spectral Properties of Fricative Consonants
Authors: Hughes George W. , Halle Morris
Published: September 2005

Energy density spectra of gated segments of fricative consonants were measured. The spectral data were used as a basis for developing objective identification criteria which yielded fair results when tested. As a further check gated segments of fricatives were presented for identification to a group of listeners and their responses evaluated in terms of the objective identification criteria.
Detection of a Signal Specified Exactly with a Noisy Stored Reference Signal
Authors: Birdsall T. G.
Published: September 2005

This paper treats the optimization problem of detecting the presence of a signal in a background of white Gaussian noise, under the restriction that the signal is specified exactly but the receiver memory contains only a noisy version of the signal. The optimum receiver is specified. The performances of both the optimum receiver and the cross-correlation receiver with a noisy memory are calculated and compared for a special case.
Iron-Aluminum Alloys for Use in Magnetostrictive Transducers
Authors: Pigott Miles T.
Published: September 2005

A systematic determination of the electromechanical coupling coefficient k has been made for Fe-Al alloys containing aluminum percentages between 12 and 14 by weight and annealed at temperatures between 600°C and 1100°C. For annealing temperatures in the neighborhood of 1000°C, k2 is about equal to 0.05 and is nearly independent of composition, a result in agreement with earlier measurements of Masumoto. For lower annealing temperatures, k2 becomes sensitive to composition, the highest value measured being equal to 0.12 for an alloy containing 12.3% Al and annealed at 650°C. In all cases eddy current losses are lower for Fe-Al than for soft annealed “A” nickel.
Use of a Velocity—Potential Function in Solving the Wave Equation for Viscous Media
Authors: Bentwich Michael
Published: September 2005

It is shown that though the wave equations for viscous and non-viscous media are similar, the use of a potential function is not always permissible in the viscous case. Statements made by Mintzer and Tanenbaum are analyzed accordingly.
Effect of Transport Processes on Attenuation and Dispersion in Aerosols
Authors: Soo S. L.
Published: September 2005

Dispersion and attenuation of sound waves (sonics and ultrasonics) in aerosols were studied. Effects of momentum and heat transfer between the solid particles and the gas were considered. Significance of relative acceleration of particles is demonstrated.
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.
Sources of Sound in Piezoelectric Crystals
Authors: Jacobsen E. H.
Published: September 2005

The production of sound in piezoelectric crystals is examined from the viewpoint of the inhomogeneous wave equation. It is shown that sound is generated by a gradient in the piezoelectric stress and that consequently the free surfaces of a piezoelectric crystal are usually the most effective wave sources. The excitation of sound at microwave frequencies is also discussed and shown to be equivalent to the case of rf excitation at low frequencies.
The Vobanc—A Two-to-One Speech Band-Width Reduction System
Authors: Bogert Bruce P.
Published: September 2005

The Vobanc VOice BANd Compressor) is a speech band-width reduction system which provides a reduction of two in transmission channel band width, without a comparable loss in articulation. A description is given of an experimental system and results obtained with it are described.
Compensatory and Pursuit Tracking of Loudness
Authors: Pikler Andrew G. , Harris J. Donald
Published: September 2005

In the compensatory form of loudness tracking, S keeps a loudness level constant in the face of programmed changes; in the pursuit form, he duplicates the loudness changes by manipulating an external source. Five subjects were required to track three tape-recorded programs presented in eight test conditions, including both modes (compensatory and pursuit) and three channel types of reception (monotic, diotic, dichotic). The responses were obtained by dial-writing techniques and a paper-tape voltage recorder. Analysis of variances based on 120 tracings revealed the overall superiority of the compensatory mode (averaged momentary error 2.2 db) vs the pursuit mode (3.3 db). High accuracy and consistency obtainable in auditory tracking suggest its use for the purposes of suprathreshold audiometry and for human engineering tasks in compensatory and pursuit displays.
Outlining Effect in Ultrasonic Images
Authors: Suckling E. E. , Maclean W. R.
Published: September 2005

Acoustical shadows observed in the transmission of sound through biological material are accounted for by refraction and total reflection.
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.
Effect of Attenuating One Channel of a Dichotic Circuit upon the Word Reception of Dual Messages
Authors: Tolhurst Gilbert C. , Peters Robert W.
Published: September 2005

Listeners responded to two simultaneous messages through dichotic headset circuits. Each message consisted of word groupings from the multiple-choice intelligibility tests. The signal level of one of the messages remained constant while the level of the contralateral message was attenuated in five steps of three decibels each step. The variable under study was the effect of these attenuation levels upon the reception of the two messages. The simultaneous messages were received under conditions of noise and quiet. The findings were that the general effect of attenuating one of the simultaneous messages was that of decreasing the reception scores of the attenuated message and increasing the reception of the unattenuated message. The effect was more pronounced in noise than in quiet.
Noise from Cavitating Submerged Water Jets
Authors: Jorgensen Donald W.
Published: September 2005

Frequency spectra of the underwater noise produced by cavitating submerged water jets were determined experimentally for nozzle diameters from 38 to 112 in., efflux velocities from 40 to 175 ft/sec, and ambient pressures up to 2 atm. When cavitation is barely incipient, the rms sound pressure varies with differences in the manner of handling the water prior to a run; this variation of sound pressure is presumably due to changes in the nuclei content of the water. When, however, the cavitation index is sufficiently small, cavitation is well advanced, and then the radiated sound is independent of the manner of treating the water. For this condition a simple relation is found to exist among the noise spectra when they are plotted as dimensionless functions of those physical quantities which determine the flow.
Sound Propagation in the Lower Atmosphere
Authors: Rothwell P.
Published: September 2005

An account is given of experiments carried out in the lower troposphere to compare observations of audible range and of angle of descent of sound from shell bursts at various heights up to 10 000 ft with calculations made from elaborately measured temperatures and winds. In stable conditions there is satisfactory agreement. Several cases were observed of anomalous propagation in which sound rays starting upward from the source are bent back to the earth. These showed the phenomena associated with anomalous propagation on the larger scale, namely, inner and outer audibility zones, “zone of silence,” and double or multiple reception of the single pulse from the source. From the experience gained in these experiments suggestions are made for (1) observation of the time interval between components of the usual double or multiple bangs from a single pulse source and (2) observation of the sound from explosions in the air as well as on the ground to obtain more information than has been obtained hitherto from sound propagation, about temperature and wind in the high atmosphere. Rocket explosions might be used for the latter purpose.
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.
Experimental Study of Diffraction and Waveguide Effects in Ultrasonic Attenuation Measurements
Authors: Carome E. F. , Witting J. M. , Fleury P. A.
Published: September 2005

An experimental study has been made of the propagation of ultrasound in liquids under both free-field and guided-wave conditions. Free-field measurements have been made from 1 to 20 Mc in low absorbing liquids, employing both circular and square sound sources. These measurements indicate that the correction for diffraction loss predicted by existing theories is applicable only so long as this loss is smaller than the true absorption. Attenuation measurements also have been made in liquids confined in various cylindrical and rectangular metallic waveguides. For a given configuration, the observed variation with path length of the attenuation follows closely that predicted theoretically for propagation in a solid sample of the same dimensions. Some consideration is given to possible sources of this result which differs somewhat from the predictions of current theories.
Ultrasonic Absorption in Metals at Elevated Temperatures
Authors: Zucker Charles
Published: September 2005

The use of the ultrasonic pulse technique as a means of measuring ultrasonic absorption in an aluminum alloy (2S) at high temperatures has been considered. The absorption for both the longitudinal and shear waves was computed. These measurements show that the absorption is relatively constant up to approximately 200°C where it then experiences a large increase. The major part of the absorption at high temperatures is found to be due to thermal effects.
Bottom Reverberation for 530- and 1030-cps Sound in Deep Water
Authors: Mackenzie K. V.
Published: September 2005

Bottom reverberation measurements were made during September, 1954, with 530- and 1030-cps sound in 2100 fathom water near San Diego for ping durations of 0.1, 0.25, 0.5, 1.0, and 2.0 sec with omnidirectional sources and receivers. The data were analyzed by assuming that the returned sound consisted of both specularly and nonspecularly reflected sound, analogous to the regular and diffuse reflected light from Bristol board. At normal incidence the losses on reflection for the 530- and 1030-cps sound were 19.5±2.5 db and 15.4±1.7 db, respectively. The other sound returning from the bottom as reverberation was assumed to be due to nonspecular reflections obeying Lambert's law of diffuse reflection. The reverberation level due to the nonspecular reflections was then analyzed to obtain the scattering constant μ of the bottom. A value of 10 logμ=−27 db was obtained for both the 530- and 1030-cps sound. The curves computed for a sine squared dependence fit the data for grazing angles from 90° to 30°. A comparison with published values of other investigators indicates that for clays, muds, or fine grained sands there appears to be no significant frequency dependence over a range of seven octaves.
Earphone, Probe Tube Microphony, and Audiometric Zero
Authors: Harris J. Donald
Published: September 2005

Reporting audiometric threshold in terms of SPL at the entrance to the ear canal makes the assumption that equal SPL Fields equal loudness regardless of the type earphone used. This is shown not to be always the case. Loudness balances between the W.E. 552 and the W.E. 705 A phone yield data composing differences among three laboratories as to what SPL at the entrance to the ear canal constitutes American “audiometric zero.” Loudness balances and threshold measurements using the W.E. 705 A and a British earphone, Standard Telephones and Cables Ltd. Type 4026 A, show the British phone generating more SPL at the entrance to the ear canal for equal loudness. This difference must be added as a correction factor to ear canal SPL using the 705 A earphone if one wishes to compare American threshold surveys with British surveys by probe tube microphony.
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 <M <0.8 and 1.5×106<Re<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.
Torsional Wave Propagation in Hollow Cylindrical Bars
Authors: Clark S. K.
Published: September 2005

The characteristic equation governing the propagation of waves of pure torsion in a hollow cylindrical rod are developed, and values of the characteristic numbers governing the velocity of torsion wave propagation for the first five modes of motion are presented for both solid rods and various geometries of hollow cylindrical rods. The extremes of geometry are also investigated, that is, the case when the radius of the hole in the rod approaches zero and the case where the wall thickness of the rod approaches zero. The presence of the central hole in the cylinder has no effect on the velocity of propagation of these waves for the primary mode, but for higher modes the wave velocities increase with decreasing ratios of wall thickness to outside diameter.
Wave Propagation through Fluid Contained in a Cylindrical, Elastic Shell
Authors: Lin T. C. , Morgan G. W.
Published: September 2005

A study is presented of the propagation of axisymmetric waves through compressible, inviscid fluid contained in a cylindrical, elastic shell. The dependence of the phase velocity as a function of frequency on four dimensionless parameters of the system is discussed and illustrated graphically.
Vibrations in Long Rods of Barium Titanate with Electric Field Parallel to the Length
Authors: Stepheson C. V.
Published: September 2005

The theory has been developed for vibrations in long thin rods of piezoelectric barium titanate with the electric field parallel to the length. The theory shows how the coupling coefficient k23 and the piezoelectric constant d33 are related to a measurement of the fundamental resonant and antiresonant frequencies. The antiresonant frequency in this mode of vibration is controlled by the physical properties of the material in exactly the same way that these properties control the resonant frequencies in other modes. An experiment was devised, and the results of the experiment verified this result.
Demonstration of the “Least Stable Waveform” of Finite Amplitude Waves
Authors: Breazeale M. A. , Lester W. W.
Published: September 2005

A backward-sloping ultrasonic wave is generated by reflection of a finite amplitude distorted wave from a pressure-release boundary. The difference between the behavior of this wave and that of a wave distorted in the usual sense is demonstrated.
Application of Two Ultrasonic Methods to the Determination of the Ratio p/q of the Photoelastic Constants of Optical Glasses
Authors: Gates H. F. , Hiedemann E. A.
Published: September 2005

The ultrasonic methods of Bergmann and Fues and of Mueller for the determination of the ratio p/q of the photoelastic constants of glasses were applied to a series of American optical glasses and to fused silica. Mueller's method gave significant results which are given in tables.
Acoustic Properties of the Ocean Bottom at Bahia Todos Santos, Lower California
Authors: Horton C. W.
Published: September 2005

The transmission data which were obtained at Bahia Todos Santos, Lower California, by the University of California, Division of War Research, have been analyzed. It is shown that at a frequency of 200 cy/sec the observed propagation agrees quite well with a formula developed by Camp and Eckart. This formula, which is based on the assumption that the bottom acts like an acoustic impedance, predicts that the observed pressure should decrease with the three-fourths power of the distance. When the data are fitted with the formula, one obtains an average value of 1.25 for the ratio of (ρc of the bottom/ρc of the water).
Factor Analysis of Cochlear Injuries and Changes in Electrophysiological Potentials Following Acoustic Trauma in the Guinea Pig
Authors: Eldredge Donald H. , Bilger Robert C. , Davis Hallowell , Covell Walter P.
Published: September 2005

The changes in “threshold” and maximum responses for cochlear microphonic potentials and whole-nerve action potentials were measured following acoustic trauma with 500-cps tones. The cochlear-microphonic responses were measured locally in the first turn of the cochlea for 500-, 2000-, and 8000-cps test tones and locally in the third turn for a 500 cps test tone. The whole-nerve action potentials were measured in response to 500- and 5000-cps tone pips. Injury to the organ of Corti in the first and third turns was rated after examination of histological sections of the temporal bones. The physiological measurements, the injury ratings, and the sound pressures and durations of the traumatic exposures were examined together for correlations and analyzed for common factors. The results served primarily to confirm previous conclusions. For durations of exposure from 5 to 80 min, equal total acoustic energy in the exposure produced equal changes in the electrophysiological responses. The ratings of anatomical injury in the cochlea departed significantly from this relation and tended to depend more strongly on sound pressure than on duration of exposure. The “threshold” shifts for CM responses from the first turn were the same for the three test frequencies, but loss of maximum potential was significantly different for the three test frequencies. The factor analysis grouped the whole-nerve AP responses to 500-cps tone pips with the CM responses from the first turn instead of with the CM responses from the third turn.
Source and Receiver Behavior in the Use of a Criterion
Authors: Egan James P. , Clarke Frank R.
Published: September 2005

A listener in an articulation test is confident of some of his responses and dubious about others. On the basis of this fact, it is reasonable to require that a receiver decide whether or not his response is correct. If he adopts various criteria from test to test, a receiver operating characteristic may be obtained which will be one way of describing quantitatively this type of behavior. The curve showing the confirming and rejecting behavior of the receiver is compared to that of the source using the same test materials and the same speech-to-noise ratio.
Scattering of Acoustic Energy by Solid and Air-Filled Cylinders in Water
Authors: Barnard G. R. , McKinney C. M.
Published: September 2005

This paper presents the results of an experimental investigation of the scattering of acoustic energy from finite circular cylinders in water. Photographs are shown of the pulses scattered in the backward direction in the plane normal to the longitudinal axis and in the plane containing the longitudinal axis of a cylinder. The echo structure exhibits characteristics dependent upon the corners of the cylinder where there is a sharp change in the slope of the projected area and discontinuities between air, brass, and water. The photographs of pulses returned from the cylinders in the plane normal to the longitudinal axes imply the existence of surface waves which travel around (the) circumferences of the cylinders. Distribution-in-angle diagrams of acoustic energy scattered in the plane perpendicular to the longitudinal axes of solid and hollow air-filled cylinders were taken for changes in cylinder length, changes in pulse length, and changes in acoustic radii. Length modes of vibration do not affect significantly the energy scattered perpendicular to the longitudinal axis. When pulses, which are long compared to the diameter of the cylinder, are used, the scattered energy distribution is dependent upon the composition and the acoustic radius of the cylinder.
Transitions, Glides, and Diphthongs
Authors: Lehiste Ilse , Peterson Gordon E.
Published: September 2005

The study deals with the formant movements associated with transitions, glides, and diphthongs in spoken American English. The transitional characteristics associated with all initial and final consonant phonemes were studied in a large sample of utterances. The rate of change of the transition from a consonant hub to the steady state vowel formant position and conversely was investigated for vowels which are commonly considered monophthongs. It is assumed that such changes are cues for the perception of the consonants rather than linguistically significant components of the vocalic nucleus. The rate of change associated with syllable nuclei commonly perceived as diphthongs, [ɑɪ], [ɔɪ], [ɑᴜ] was investigated and compared with the changes due to consonant transitions in monophthongs. Criteria are suggested by which the formant movements due to transitions may be distinguished from movements that have linguistic signalling value within the syllable nucleus.
Effect of Anoxia on Cochlear Potentials
Authors: Konishi Teruzo , Butler Robert A. , Fernandez Cesar
Published: September 2005

The anterior inferior cerebellar artery of guinea pigs was occluded, thereby interrupting the blood supply to the cochlea. Durations of occlusion ranged from 1 through 60 min. Cochlear microphonics, summating potential, action potential, and endocochlear potential were recorded before, during, and subsequent to occlusion. The differential effect of anoxia on the various potentials was observed, as well as the appearance of the large negative dc potential in scala media as anoxia progressed. For the brief occlusion durations, the amplitudes of all potentials except cochlear microphonics became greater than normal soon after the blood supply returned. Even for the longer anoxic intervals, the summating potential and the endocochlear potential exhibited super-normality during the recovery process.
Disk-Loaded Torsional Wave Delay Line. I. Construction and Test
Authors: Andreatch P. A. , Thurston R. N.
Published: September 2005

Torsional waves are propagated in a uniform diameter rod with the shear velocity (μ/ρ)12. On the other hand, the effective velocity is slower in a disk-loaded rod with alternate large-diameter and small-diameter sections. Because of the slower velocity, a disk-loaded rod will delay a signal longer than conventional ultrasonic delay lines of the same path length. This paper describes the construction of these disk-loaded torsional wave delay lines, and of electromechanical transducers for generating and detecting the torsional waves. The method of testing and the results of tests on the lines are presented. For example, a brass line having the disk diameter five times the diameter of the sections between the disks provided a delay of 114 μsec/cm at 32 kc. For contrast, the delay of a uniform diameter brass rod is only 4.5 μsec/cm.