bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tentative Recommended Practice for Laboratory Measurement of Airborne-Sound Transmission Loss of Building Floors and Walls
Authors: London A. 
Published: September 2005

The American Society for Testing Materials recently promulgated the tentative recommended practice which is reproduced below with the permission of that Society. As far as is known this is the first successful tentative standard which has been adopted in the field of architectural acoustics in this country, even though standardization efforts along these lines go back to the late 1930's. This specification was prepared by Subcommittee VII on Sound Transmission of ASTM Committee E-6 on Building Constructions. The chairman of the Subcommittee is Richard K. Cook, while members of the writing group were Albert London and William A. Jack.
Copies of the specification may be obtained from the ASTM at a cost of 25 cents each. The complete unabridged tentative is as follows (the “Society” referred to in the tentative is of course the American Society for Testing Materials).
A Precise Recording Ultrasonic Interferometer and Its Application to Dispersion Tests in Liquids
Authors: Barthel Romard , Nolle A. W. 
Published: September 2005

A precise recording ultrasonic interferometer is presented which is particularly well suited for measuring dispersion in liquids. The device is an interferometer of the two-crystal type in which the separation of the crystals is continuously varied. The recording process is equivalent to placing a mark on a rotating recording drum whenever the receiving crystal has moved a distance of one wavelength of sound in the liquid. Thus the wavelength of sound may be derived from the known mechanical constants of the system. The precision of the dispersion measurement is about 0.8 part in 10,000; the precision of the absolute determination of sound velocity is 0.2 m/sec. The instrument has been applied also to sound velocity measurements in solids under restricted conditions.
Sound velocity in distilled water at 25°C as measured with this instrument is 1496.2±0.2 m/sec, a value somewhat lower than that obtained by earlier investigators.
Dispersion in the frequency range 5–25 Mc is shown to be no greater than 0.8 part in 10,000, the limit of experimental error, for all the liquids studied: water, geraniol, xylene, isobutyl alcohol, and solutions of sucrose, NaCl, MgSO4, NaHCO3, CdCl2, CdSO4, Na3PO4, Pb(NO3)2, ZnSO4, and K3Fe(CN)6.
Radiation Pressure and Dispersion
Authors: Post E. J. 
Published: September 2005

The present paper starts with a brief discussion of the two components of acoustical radiation pressure in contrast with the single component obtained for electromagnetic radiation in vacuum. The two components of acoustical radiation pressure are correlated in a simple manner with the two distinct interaction possibilities of the obstacle and the medium, i.e., interaction with the wave motion only or interaction with the wave motion as well as with the medium itself. This picture appears to be consistent with the earlier conclusions of Brillouin and Richter.
Afterwards the result is generalized for dispersive media. It is shown that the component which is usually stated to be independent of the equation of state in the existing nondispersive theories should contain the time parameters of the equation of state in the form of a multiplying factor group, velocity over phase velocity.
The present paper stresses the basic concepts rather than mathematical detail and concludes with an extensive bibliography and commentary.
The Use of High Intensity Ultrasound in Experimental Neurology
Authors: Wall P. D. , Tucker D. , Fry F. J. , Mosberg W. H. 
Published: September 2005

The results of a histological study of the changes produced by high intensity ultrasound on tissue of the central nervous system are presented. The study was restricted to the nontemperature effects of the sound since these are of particular significance for neurology. The results obtained show that nerve cell bodies are particularly sensitive to the action of the ultrasound, while blood vessels and nerve fibers are much more resistant.
The use of a focused beam of ultrasound to produce discrete lesions deep in the brain without disturbance of the vascular system or through-going nerve tracts in the region of the lesion is demonstrated by a study on the bulboreticular inhibitor formation of the cat medulla.
Physical factors which require consideration are discussed in terms of the histological work.
The Compressibility of Solutions. II. An Ultrasonic Study of Aqueous Solutions of Some Simple Amino Acids and Their Uncharged Isomers at 25°C
Authors: Gucker Frank T. , Haag Robert M. 
Published: September 2005

Some time ago, the first author showed that the apparent molal compressibility of the solute in a dilute aqueous solution is a linear function of the square root of the concentration for electrolytes, and of the first power of the concentration for nonelectrolytes. Both of these linear relationships may hold up to fairly concentrated solutions and afford convenient interpolation formulas for the compressibility as a function of concentration. The conclusion about electrolytes has been confirmed by several others, but little has been done with nonelectrolytes.
This article describes a 4-Mc interferometer used to determine adiabatic compressibilities of solutions to about ±0.01 percent. Studies of several amino acids and their uncharged isomers, including glycine and glycolamide; α- and β-alanine and lactamide, from about 0.05 M to near saturation, show linearity with concentration in dilute solutions and a general increase in the limiting slope and decrease in the limiting value of the apparent molal compressibility with increasing dipole moment of the solute molecules. These results are interpreted qualitatively by the theories of dipolar interaction developed by Fuoss and Kirkwood, and of dipolar charging energy developed by Kirkwood, but systematic deviations are observed for the apparent molal compressibilities and the volumes and heat capacities studied previously.
Some Variables in Audio Spectrometry
Authors: Benson R. W. , Hirsh Ira J. 
Published: September 2005

Measurements of the long-time average spectrum of speech are reported with the purpose of pointing out the roles of several variables. Three different sampling times of three different types of speech material are analyzed with several band-width intervals. The speech of five young men and five young women contributes to the averaged results.
No significant differences are found among the three types of speech material nor among the three different sampling times of 30, 60, and 90 seconds. Octave, half-octave and equal-mel intervals appear to yield the same results. The only important difference between male and female speech appears in the octave 75–150 cps. The shape of the long time spectrum remains fairly constant from person to person while the over-all level contributes most to interpersonal variability. A discussion of the meaning of “over-all level” in this and previous reports is given.
A relatively simple system for obtaining these measurements is described.
Acoustical Vibrations of Rings
Authors: Kaiser Elmer R. 
Published: September 2005

The frequencies of tones when metal rings are struck in radial and axial directions have been investigated in a variety of steel and bell-metal rings.
The classical formulas relating frequency with ring dimensions and physical properties of the materials compare closely with actual measurements except for thick rings. The fundamental tone is predominant in the smaller rings but the fundamental fades and the overtones predominate as the rings increase in diameter and decrease in width and thickness.
Comments are given on musical properties of rings which may be promising but which have not been fully explored.
A Compact, Versatile Filter-Type Sound Analyzer
Authors: Scott H. H. , von Recklinghausen D. 
Published: September 2005

Availability of a pocket-sized miniature sound level meter meeting all ASA standards has created demand for a small, equally portable sound analyzer as a companion instrument. The analyzer described surpasses all applicable ASA standards. The separate high and low cut-off filters may be adjusted independently, and the noise pass band may be locked in any band width which is an integral multiple of 12 octave, from 12 octave through the standard 1 octave band, etc. The range of the filters extends one octave lower and one octave higher than the ASA standards. These features permit considerable added precision and flexibility of analysis.
For protection and ease of carrying, the instrument is housed in a leather case similar to those used for amateur motion picture cameras. The case is equipped with a shoulder strap which allows the analyzer to be carried about easily while in use. It can also be used as a general purpose adjustable filter or as a wide-range amplifier.
The Concept of Radiation Scattering and Its Application to Reinforced Cylindrical Shells
Authors: Junger Miguel C. 
Published: September 2005

This paper presents an approach which permits the analysis of elastic scatterers embodying complicated structural characteristics. Such problems cannot be investigated by means of the methods previously applied to the study of the scattering action of simple elastic bodies.
The scattered wave pressure produced by elastic scatterers may be expressed as the sum of two terms, one representing “rigid body scattering,” i.e., the scattering which would exist if the scatterer were rigid and immobile, the other representing “radiation scattering,” which is associated with the sound radiated by the scatterer vibrating under the effect of the incident wave pressure. These two terms are derived here for three important cases.
The problem is now reduced to one in elasticity, specifically to the problem of solving the equations of motion of the elastic system for its forced response. The scattering pattern can then be computed. This procedure is applied to a scatterer in the form of a cylindrical shell reinforced with regularly spaced septa.
The Measurement of the Velocity of Sound in Liquids
Authors: Graham G. M. 
Published: September 2005

A new technique for the measurement of sound velocity in liquids has been developed, which is especially suited to frequencies in the range from 0.5 to 5 mc. It employs an approximation to the boundary conditions in Guptill's closed form solution for the radiation field between two infinite walls with a piston source in one wall.
Measurements have been made in distilled water at 0.6 and 7.6 mc with an error of less than 0.2 percent in the low-frequency measurements. No dispersion is indicated to the order of the experimental error, in the temperature range from 10 to 20°C.
A description of the apparatus is given.
Masking of Speech by Bands of Noise
Authors: Hirsh I. J. , Bowman W. D. 
Published: September 2005

The threshold of intelligibility for two-syllable (spondee) words was measured in the presence of different levels of masking noise. Twelve different bands were used, one (20 to 6600 cps) approximating a white noise and each of the other eleven containing a band of frequencies corresponding to a pitch interval of 250 mels. The absolute thresholds for these bands were also measured to permit transformation of the noise level from an absolute scale to a scale of sensation level.
The results show linear relations between the masked threshold and noise level for white noise and for bands of noise between 394 and 1420 cps. For noise bands above 1420 cps this masking function is accelerated, while the two bands below 394 cps yield sigmoid masking functions. Of the bands used, the most effective contained frequencies between 670 and 1000 cps. The signal-to-noise ratio at threshold for this band was about −25 db while for bands above or below it became gradually smaller than −25 db, reaching a minimum of −60 db for the highest and lowest bands. White noise was more effective than any band, giving a threshold S/N ratio of −15 db.
Acoustic Trauma in the Guinea Pig
Authors: Davis Hallowell 
Published: September 2005

The ears of anesthetized guinea pigs were exposed to intense tones of 135, 545, 2000, or 8000 cps at sound pressures (at the eardrum) from 138 to 148 db re 0.0002 microbar. The electrical output was recorded by differential intracochlear electrodes before, during, and after the exposures.
The injury caused by 8000 cps centers in the basal turn, by 2000 cps in the second turn, by 500 and 185 cps in the third and fourth turns of the cochlea. No single tone, at the intensities and durations employed, injured all of the cochlea.
The “threshold” and also the maximum voltage of the cochlear microphonic are valid indices of the anatomical injury seen under the microscope if the proper test frequencies and positions of electrodes are used.
The destructiveness of a tone does not depend on its frequency. Equally severe (probably permanent) injuries were produced by a one-minute exposure at all four frequencies tested when the intensity level was about 144 db at the eardrum.
Acoustic Spectrum Terminology
Authors: Heindsmann T. E. 
Published: September 2005

Terminology used to describe line spectra is discussed. It is proposed that “discrete component” be used to describe the individual elements comprising a line spectrum and that “tonal component” be used to describe its auditory equivalent.
Editor's Note: The kind of confusion mentioned in this letter may result from failure to distinguish between cause and effect. See note in Sec. 6 of the American Standard Acoustical Terminology Z24.1–1951, in regard to such words as tone, which “are used to refer both to the production of sound waves and to the nature of the associated sensation. There is often not complete correspondence between the two; which of the two meanings is desired must be made clear from the context or units of measurement.” It may be remarked, also, that in acoustics it is the sound pressure which is commonly measured directly—only very rarely the sound intensity.
American Standard Acoustical Terminology Z24.1–1951 is about to be revised. Suggestions for the improved wording of these definitions are welcomed. They may be addressed to the Chairman of Writing Group Z24-W-5, R. W. Young, U.S. Navy Electronics Laboratory, San Diego 52, California.
Attenuation of Repeated Shock Waves in Tubes
Authors: Werth Glenn C. , Delsasso Leo P. 
Published: September 2005

As very intense sound waves propagate, the wave-shape changes into one of saw-tooth form producing abrupt rises in pressure called shock fronts. This waveform distortion into so-called repeated shock waves is caused by the nonlinearity of the medium. The objective of this study has been to obtain experimental facts relative to the propagation of repeated shock waves in tubes and to compare these with existing theory. An intense sound source was constructed and appropriately coupled to a series of measuring tubes. Observations were made on the velocity and attenuation of fully developed shock waves for a variety of gases, for pressure amplitudes as great as 0.25 atmosphere, and for a fundamental frequency range of from 400 to 1200 cycles per second.
The data were compared with previous theoretical work, particularly that of Professor Rudnick. Agreement was found in the general aspects of the theory; the exact magnitude of the effect remains to be explained. This discrepancy between theory and experiment may be resolved by considering in greater detail the absorptive processes involved.
Determination of Absolute Sound Levels and Acoustic Absorption Coefficients by Thermocouple Probes—Experiment
Authors: Fry William J. , Fry Ruth Baumann 
Published: September 2005

A stable, readily constructable thermocouple probe has been developed for determining absolute sound levels in ultrasonic fields in liquid media. This paper includes criteria for design of such probes and a discussion of experimental measurements made with such a device.
It is a consequence of the method that if the sound intensity at an appropriate size thermocouple junction imbedded in an absorbing medium is known the acoustic absorption coefficient of the material can be determined. The method thus makes possible the determination of absorption coefficients of minute quantities of material.
The probe consists of a thermocouple imbedded in a sound absorbing medium which closely matches in density and sound velocity the medium in which the sound level is to be determined. In use the transducer which generates the acoustic field is exctied to generate sound pulses with a rectangular envelope. The initial time rate of change of the temperature at the thermocouple junction is determined. In addition to the measurement of the temperature change, the calculation of the absolute sound intensity requires only a knowledge of the absorption coefficient of the imbedding material and its heat capacity per unit volume at the temperature at which the measurements are made.
The experimental results include a comparison of the sound level determined by a thermocouple probe and a determination by radiation pressure methods. The values obtained by the two methods agree within the uncertainty of the experimental measurements.
Transmission of Sound through Thin Elastic Plates
Authors: Young James E. 
Published: September 2005

The transmission of sound through thin elastic plates set in a plane infinite baffle or an infinite duct is discussed in some detail. A two-dimensional configuration is considered in both instances. The problems then are the transmission through a strip set in an infinite baffle and transmission through a plate set in a duct supporting lowest mode propagation.
These systems make it possible to indicate in a formal manner how the boundary conditions affect transmission. The notion of bending impedance is used as a means of categorizing the mounting conditions.
Experimental investigations of the transmission through circular plates in ducts of the same cross section were carried ont. It is shown that the transmission loss varies with the manner in which the plates are mounted. The conditions under which this behavior is predictable are discussed.
The Measurement of Human Channel Transmission Characteristics
Authors: Munson W. A. , Karlin J. E. 
Published: September 2005

The full benefits of modern communication engineering will be realized only when we have enough quantitative knowledge of the transmission properties of the human communication channel to guide technological development. This deficiency is a limiting factor in the effort to achieve economy of transmission through more efficient use of the time and frequency dimensions in peace time telephony and television; it has also become of serious concern in our inability to extract adequate information from marginal signals in military applications.
This paper uses concepts in information theory and psychophysics to provide a basis for the quantitative measurement of certain communication properties of the human being. Part 1 of the paper discusses testing techniques in which binary signals were used for measuring information transmitted over a human communication channel. Part 2 proposes a model of this channel for investigating the factors which influence this information rate. The model involves three parameters: the signal level, the noise level of the human circuits, and the discriminant level of the human circuits. Some illustrative experimental measurements of these parameters are included.
Ultrasonic Hysteresis in Viscous Liquids
Authors: Litovitz T. A. , Lyon T. 
Published: September 2005

The ultrasonic absorption coefficients for longitudinal waves in glycerol and pentachlorobiphenyl are measured over the frequency range from 7.5 to 70 Mc. The measurements are made in the range of viscosities from 105 to 107 poise so that the ultrasonic frequencies used are well above the main relaxation frequencies associated with viscous flow processes in these liquids. The results indicate that the absorption coefficient per cm can be represented by the expression α = B plus; Hf, where B and H are constants and f is the ultrasonic frequency. The constants B and H in both liquids are found to decrease with increasing temperature, exhibiting an “apparent” activation energy of about 24 kcal/mole and 12 kcal/mole for the pentachlorobiphenyl and glycerol respectively.
It is concluded that the results found here indicate that both terms B and Hf found in a could best be explained by assuming that one or more distributions of relaxation times exist.
It is suggested that ultrasonic hysteresis in both liquids and solids have a common origin indicating that the hysteresis effect in liquids is not related to the viscous flow mechanism causing the absorption maximum at lower frequencies and viscosities. A possible mechanism offered for the hysteresis loss is the coupling of the acoustic energy into heat energy due to the anharmonicities in the lattice structure.
Ultrasonic Temperature Measurement in Internal Combustion Engine Chamber
Authors: Livengood J. C. , Rona T. P. , Baruch J. J. 
Published: September 2005

A method and apparatus for measuring the velocity of propagation of sound in the gases within the combustion chamber of an operating internal combustion engine are described. Two barium titanate crystals are used to generate and receive transient acoustical signals of approximately 2 Mcps. A calibrated commercial oscilloscope is the time base of the system.
From the value of the velocity of sound it is possible to compute the temperature of the portion of the engine gas which lies in the measuring path, provided it is permissible to assume that the gas mixture behaves like a perfect gas, that it is of known composition, and that thermal relaxation effects are negligible. The maximum error is estimated at 4.7 percent and experiments indicate a dispersion of results less than 1 percent.
An Experimental Study of Acoustically Induced Cavitation in Liquids
Authors: Galloway William J. 
Published: September 2005

An apparatus has been assembled for the study of sonically induced cavitation in the frequency range of 20 to 40 kilocycles. Radially symmetric standing waves are produced in a spherical resonator driven externally by a magnetostriction transducer. The acoustic pressure within the sphere is measured by a small barium-titanate transducer positioned at secondary maxima of the standing pressure wave. Equipment is provided for measuring the gas content of the liquid being studied.
Measurements of cavitation thresholds as functions of air content, hydrostatic pressure, temperature, and surface tension have been made using different liquids. The highest thresholds measured were 200 bars for water and 140 bars for benzine (petroleum ether).
The air content of the liquid appears to be the dominant factor limiting the maximal negative pressure which the liquid can withstand as long as the air content is greater than five percent of saturation. At lower percentages of air saturation the threshold becomes essentially independent of air content, becoming limited by as yet undetermined factors.