bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of prostate cancer despite late onset androgen deficiency
Authors: SENGUPTA SHOMIK , DUNCAN HENRY J , MACGREGOR ROBERT J , RUSSELL JOHN M 
Published: September 2005

Abstract Androgen withdrawal causes the regression of prostate cancer and is used in therapy, but the role of androgens in the development of prostate cancer is uncertain. We present a case of prostate cancer diagnosed in a man who had been clinically androgen deficient for some years. This case and reviewed literature suggest that while early androgen exposure may be important in the prostatic carcinogenesis, late onset androgen deficiency is not protective. Thus, hypogonadal men considering androgen replacement therapy need to be adequately counseled, screened for prostate cancer and followed closely during treatment.
Curved crack propagation in homogeneous and graded materials
Authors: TILBROOK M. T. , MOON R. J. , HOFFMAN M. 
Published: September 2005

ABSTRACTDeflection and deviation of cracks commonly occurs because of asymmetry in crack‐tip stresses in both homogeneous materials and functionally graded materials (FGMs); yet the analysis of curved cracks has been limited to simple crack shapes, otherwise the analysis would involve extensive levels of computation. The present study investigates the approximation of curved cracks with simplified shapes. A simple analytical model justifying the use of crack‐shape approximations, developed in an earlier study on stationary curved cracks in homogeneous materials, is outlined. Then, the approach is applied to propagating cracks in both homogeneous and graded material structures. Results are presented from finite element (FE) simulations of crack propagation using exact and simplified crack shapes. The use of an approximated crack shape can provide basic estimates for crack propagation path and critical load. However, systematic divergence can occur between predictions for exact and approximated crack shapes, particularly in inhomogeneous material configurations, and so the development of solutions for non‐straight cracks in FGMs would be expedient.
Nanoscopic fatigue and stress corrosion crack growth behaviour in a high‐strength stainless steel visualized in situ by atomic force microscopy
Authors: MINOSHIMA K. , OIE Y. , KOMAI K. 
Published: September 2005

ABSTRACT In situ atomic force microscope (AFM) imaging of the fatigue and stress corrosion (SC) crack in a high‐strength stainless steel was performed, under both static and dynamic loading. The AFM systems used were (1) a newly developed AFM‐based system for analysing the nanoscopic topographies of environmentally induced damage under dynamic loads in a controlled environment and (2) an AFM system having a large sample stage together with a static in‐plane loading device. By using these systems, in situ serial clear AFM images of an environmentally induced crack under loading could be obtained in a controlled environment, such as in dry air for the fatigue and in an aqueous solution for the stress corrosion cracking (SCC). The intergranular static SC crack at the free corrosion had a sharp crack tip when it grew straight along a grain boundary. The in situ AFM observations showed that the fatigue crack grew in a steady manner on the order of sub‐micrometre. The same result was obtained for the static SC crack under the free corrosion, growing straight along a grain boundary. In these cases, the crack tip opening displacement (CTOD) remained constant. However, as the static SC crack was approaching a triple grain junction, the growth rate became smaller, the CTOD value increased and the hollow ahead of the crack tip became larger. After the crack passed through the triple grain junction, it grew faster with a lower CTOD value; the changes in the CTOD value agreed with those of the crack growth rate. At the cathodic potential, the static SC crack grew in a zigzag path and in an unsteady manner, showing crack growth acceleration and retardation. This unsteady crack growth was considered to be due to the changes in the local hydrogen content near the crack tip. The changes in the CTOD value also agreed with those of the crack growth rate. The CTOD value in the corrosive environment was influenced by the microstructure of the material and the local hydrogen content, showing a larger scatter band, whereas the CTOD value of the fatigue crack in dry air was determined by the applied stress intensity factor, with a smaller scatter band. In addition, the CTOD value in the corrosive environment under both static and dynamic loading was smaller than that of the fatigue crack; the environmentally induced crack had a sharper crack tip than the fatigue crack in dry air.
Fatigue crack growth for a surface crack in a round bar under multi‐axial loading condition
Authors: YANG F.‐P. , KUANG Z.‐B. 
Published: September 2005

ABSTRACTIn this paper, the fatigue life, surface crack extension direction and crack growth rate in an elastic bar with a circular cross section are determined through experiments under cyclic torsion with axial static and cyclic tension/compression loading. The effects of the loading type, loading value and stress ratio on the crack growth behaviour are discussed. The results show that, under pure fatigue torsion loading, the crack extension direction is almost the same whatever the value of torsion loading. Under fatigue torsion with cyclic tension loading, it is found that the crack extension direction is mainly determined by the alternating parts of the stresses and is almost independent of the average parts of the stresses, whereas the fatigue life is obviously dependent on the average stress.
A simplified fretting test methodology for complex shaft couplings
Authors: HYDE T. R. , LEEN S. B. , MCCOLL I. R. 
Published: September 2005

ABSTRACTA methodology is offered for the experimental simulation of fretting conditions in complex shaft couplings, using a simple representative specimen/test rig. The geometry and loading conditions of the representative specimen are designed to simulate the contact traction and slip at arbitrary positions along the length of engagement of the spline coupling, as predicted by detailed finite element modelling of the coupling. The representative specimen/test rig design is achieved via an iterative finite element process with feedback from preliminary measurements. The cyclic behaviour of the representative specimen correlates well with the results from a reduced scale aeroengine‐type spline coupling. The representative specimen approach can facilitate investigation of damage mechanisms in spline, and other, couplings, particularly fretting fatigue and wear within the contact regions, as well as plain fatigue due to tooth bending along the tooth fillet, thus offering an economical approach to the development and testing of spline couplings.
Scattering of Ultrasonic Waves in Gases
Authors: Mokhtar M. , Shehata M. 
Published: September 2005

Ultrasonic beams of frequencies in the range of 80 kc/sec. to 1000 kc/sec. emerge from a rectangular slit of known adjustable width into air, oxygen, or carbon dioxide. The disposition of the field in front of the slit is studied by the aid of a hot wire anemometer, which gives the angle of divergence of the beam and the intensity distribution across the main and the diffracted beams.
The results obtained indicate that the laws of diffraction are valid so long as the gas is far removed from its anomalous dispersion region. CO2 in the range between 100 and 200 kc/sec. shows a high degree of scattering with the result that the emergent beam loses its definition completely and becomes very diffused.
The Intelligibility of Interrupted Speech
Authors: Miller George A. , Licklider J. C. R. 
Published: September 2005

This paper concerns the effects of interrupting speech waves—turning them on and off intermittently or masking them with intermittent noise—upon their intelligibility. The effects were studied with various rates of interruption and with the speech left undisturbed various percentages of the time. Tests were conducted (1) with speech turned on and off in quiet, (2) with continuous speech masked by interrupted white noise, and (3) with speech and noise interrupted alternately, the speech wave being turned on as the noise wave was turned off, and vice versa.
(1) When the speech wave is turned on and off infrequently, the percentage of the message that is missed is approximately the same as the percentage of time the speech is off. When the interruptions are periodic and occur more often than 10,000 times per second, the interruptions do not interfere with the reception of the message. In the quiet it is easy to understand conversational speech so long as the interruptions occur more than 10 times per second.
(2) When continuous speech waves are masked by noise that is interrupted more than 200 times per second, intelligibility is independent of the interruption frequency and of the percentage of time the noise is on, provided the ratio of average speech power to average noise power is held constant. Interrupted masking noise impairs intelligibility least if the frequency of interruption is about 15 per second.
(3) When interrupted speech and interrupted noise alternate at frequencies below 10 alternations per second, the noise does not impair intelligibility. At higher frequencies of alternation the temporal spread of masking becomes appreciable.
The general features of these results are approximately the same whether the interruptions occur periodically or at random.
The Determination of Reverberant Sound Absorption Coefficients from Acoustic Impedance Measurements
Authors: London Albert 
Published: September 2005

A method is described for utilizing normal absorption coefficient or acoustic impedance measurements to predict reverberant sound absorption coefficients. The average of coefficients for the six standard frequencies determined from acoustic impedance measurements agrees closely with the average reverberant coefficient, for cases where the material may be said to obey the normal impedance assumption. The normal absorption coefficients of some 26 different acoustic materials were measured at 512 c.p.s Using the method given in the paper, the predicted reverberant coefficient deviated from the measured reverberant coefficient by 0.05 or less for 18 materials, while in only 3 cases were the deviations greater than 0.10. The method should be particularly applicable to the problem of acceptance testing of installed acoustic materials.
In the theoretical development, best agreement with experiment was obtained by introducing a new kind of reverberant statistics which associates with each wave packet in a random field a scalar quantity equal to the square of the absolute value of the sound pressure in each packet, instead of the customary energy flow treatment. Also, it was found necessary to carry out the analysis using a concept of equivalent real impedance to replace the usual complex impedance.
A Review of the Absorption Coefficient Problem
Authors: Sabine Hale J. 
Published: September 2005

In 1939 a symposium was held by the Acoustical Society of America on the measurement of absorption coefficients. In these and other papers, the reverberation chamber method of determining absorption coefficient was analyzed, and explanations for discrepancies between different chambers, and lack of agreement with other methods, were presented in terms of newly developed theory. Since that time, however, practically no progress has been made in the application of this theoretical work. The discrepancies remain unresolved, and the practical problems resulting therefrom have become increasingly serious.
Within recent months, interest in this subject has been strongly reactivated through the attention of three groups, namely, the American Standards Association, the American Society for Testing Materials, and the Acoustical Materials Association. By closely coordinated efforts, these groups are making a new attempt to develop methods of measuring and rating the absorptive properties of acoustical materials which will yield consistent results in the form most useful for practical engineering work and at the same time are grounded in well-established acoustical theory.
In the present paper, the general problem is outlined from the viewpoint of the acoustical materials manufacturer. Directions of further development in theory and of experimental attacks are suggested.
Influence of the Relative Radial Thickness of a Ring on Its Natural Frequencies
Authors: Buckens F. 
Published: September 2005

The flexural vibrations of a ring in its plane are studied by taking shear effect into account, and it is proposed to compute the deviation from the classical frequency formula, which is only valid for very small ratios of the thickness to the diameter. In a second chapter the possibility of extension is included, and in this procedure the frequencies of extensional vibrations are obtained as a by-product.
It is seen that the shear effect plays a predominant role in the deviation from the classical formula, and is more important than curvature effects and the rotational inertia. Extensibility influence is found to be very small.
An interesting comparison can be made with the similar influence of secondary factors on the flexural vibration's frequencies of a straight beam.
The Calculation of Vowel Resonances, and an Electrical Vocal Tract
Authors: Dunn H. K. 
Published: September 2005

By treating the vocal tract as a series of cylindrical sections, or acoustic lines, it is possible to use transmission line theory in finding the resonances. With constants uniformly distributed along each section, resonances appear as modes of vibration of the tract taken as a whole. Thus, the fundamental mode of the smaller cavity may be affected considerably by a higher mode of the larger; and in addition, higher resonances are found without postulating additional cavities. This is an advantage over the lumped constant treatment, where it is necessary to postulate a different cavity for each resonance, and where the interaction terms in the equation do not include the higher modes of vibration. Under the distributed treatment, dimensions for each vowel may be taken from x-ray photographs of the vocal tract. The calculations then yield at least three resonances which lie in the frequency regions known for the vowel, from analyses of normal speech. Dependence of the different resonances upon the different cavities is discussed in some detail in the paper.
An electrical circuit based on the transmission line analogy has been made to produce acceptable vowel sounds. This circuit is useful in confirming the general theory and in research on the phonetic effects of articulator movements. The possibility of using such a circuit as a phonetic standard for vowel sounds is discussed.
Changes in Pitch of Tones of Low Frequency as a Function of the Pattern of Excitation Produced by a Band of Noise
Authors: Egan James P. , Meyer Donald R. 
Published: September 2005

The excitation pattern of a tone is markedly altered by a masking stimulus. It should be expected that the pitch of the masked tone, as well as its threshold and its loudness, would be affected. In the present investigation the effect of a narrow band of noise (90 c.p.s. wide, centered at 410 c.p.s.) upon the pitch of pure tones of low frequency was measured in a series of experiments. Subjects matched the pitch of a tone heard in the presence of a band of noise to the pitch of a tone heard alone. These two tones, one partially masked and the other not, were presented to the subject in repeated succession. The listener first matched these tones for loudness. He then adjusted the frequency of the unmasked tone until it was the same in pitch as the masked tone. The pitch change was investigated at a number of frequencies and of loudness levels.
Systematic changes in pitch were observed. The presence of the noise raises the pitch of a partially masked tone whose frequency is immediately above those of the band of noise. This change in pitch occurs even though the intensity of the masked tone is greater than that of the unmasked tone. In contrast, the presence of the masking noise lowers the pitch of a tone whose frequency is just lower than those of the band of noise, but this change is largely accounted for in terms of the intensity difference required for an equal loudness match. An attempt is made to account for the changes in pitch in terms of a place theory.
Ultrasonic Absorption in Liquids
Authors: Moen C. J. 
Published: September 2005

A reverberation method has been used to measure the absorption of sound at frequencies down to 140 kc in a number of liquids of widely different properties. For glycerol the experimental result agrees well with that predicted by classical theory. For benzene and water good agreement is found with the values calculated using the modified theory employing the values of second viscosity determined by Liebermann. The absorption in carbon disulfide agrees well with Ouang's result. For these four liquids the absorption is found to be proportional to the square of the frequency, but results indicate that toluene has a relaxation frequency of the order of 105 sec−1.
The reverberation method is especially useful at the lower ultrasonic frequencies, where loner wave-lengths and lower absorption render methods used at higher frequencies less reliable or unusable.
The Error Due to Masking in the Measurement of Aural Harmonics by the Method of Best Beats
Authors: Egan James P. , Klumpp Roy G. 
Published: September 2005

The method of best beats has been employed to estimate the intensities of aural harmonics and of combination tones. It has been generally assumed that the listener hears best beats when the exploring tone produces in the cochlea a disturbance that is equal in magnitude to that of the aural harmonic or of the combination tone being measured. However, as the experiments to be reported will show, when the tone to be measured is near the absolute threshold or is partially masked, the most prominent beats will be heard when the intensity of the exploring tone exceeds that of the unknown tone. Consequently, since aural harmonics and combination tones are partially masked, their intensities will be overestimated when the method of best beats is used. The present paper concerns the magnitude of this error of overestimation.
A procedure is presented by which a better estimate of the intensity of an aural harmonic or of a combination tone may be made. When the tone being measured by the method of best beats is well above threshold, the listener hears beats over a wide range of intensities of the exploring tone, and the error of over-estimation is small. However, when the tone being measured is near threshold, there is a small range of audible beats, and the error of overestimation is of considerable magnitude. It is therefore possible to correct for this error by determining the range of intensities of the exploring tone over which beats are audible as well as the intensity of the exploring tone required for best beats. Application of this procedure to the measurement of a second aural harmonic is illustrated.
An explanation is given of the fact that the intensity of a tone near its absolute threshold will be overestimated by use of the method of best beats. This explanation is formulated in terms of the relation of the minimum and the maximum of the envelope of the beating complex to the listener's threshold for the tones that beat.
A Strain-Gauge Type Artificial Mastoid
Authors: Carlisle R. W. , Pearson H. A. 
Published: September 2005

An artificial mastoid for testing bone conduction receivers is described. It consists essentially of a stiff metal bar which has a fundamental resonant frequency above the measurement range, with a strain-sensitive translating element fastened to the under side and a compliant pad on top.
The translating element is a slab of activated ceramic, which is essentially invariant to humidity and temperature changes. The compliant pad generally used is Koroseal No. 74, which simulates the flesh over the mastoid prominence reasonably well. Koroseal No. 15 simulates flesh better but is less rugged. Calibration methods are discussed.
A Method for Determining the Propagation Constants of Plastics at Ultrasonic Frequencies
Authors: McSkimin H. J. 
Published: September 2005

A pulse technique particularly suited to dissipative materials is described for measuring attenuation and phase shift constants of plastics, using either transverse or longitudinal waves in the frequency range of 5–50 Mc.
A thin wafer of the material under test is placed between two identical fused silica buffers; and waves generated by quartz crystals at the ends of the assembly are transmitted simultaneously through the specimen in both directions. Comparison of transmitted and reflected components by means of a special balancing circuit provides information from which the complex propagation constant can be calculated, and hence dynamic rigidities and viscosities.
Illustrative data for polyethylene and Nylon are given.
The Influence of Interaural Phase on Masked Thresholds I. The Role of Interaural Time-Deviation
Authors: Webster Frederic A. 
Published: September 2005

When a narrow band of noise, of constant level (the signal) is masked by a wider band of noise (the masker), the amount of noise required to drown out the signal often depends significantly upon the interaural phase relations of signal and masker. Thus, more masking noise is required if the signal is 180° out of phase at the two ears than if it is in phase: provided that the masker remains in phase. The out-of-phase signal, in other words, shows an advantage in audibility. The advantage is very striking for a signal near 250 cps; and falls off progressively toward 1400 cps, above which it is small. At all frequencies between 250 and 6000 cps, the level of masking, for a signal in phase at the ears, remains relatively constant.
An important property of physical stimuli that produce an audibility-advantage is an interaural phase-deviation caused by the signal. When the signal is added to a corresponding masking component, the combined pressure-wave, on the average, leads in one ear and lags in the other. The resulting phase-deviation depends upon the relative levels and phase-positions of the masking and masked components. It is maximum when these components are 90° apart. The interaural time-deviation thus produced depends also upon frequency. If the frequency is increased, the level of the masking component must be decreased in order to hold the time-deviation, associated with the different frequencies, constant.
The present experiments showed that, with the out-of-phase signal, the decline in level of masking, as a function of frequency, is just such as to hold the interaural time-deviation (for the 90° position) constant at about 125 microseconds. Tonal signals tend to show a decreasing critical time-deviation with increasing frequency.
Dispersion of Velocity and Anomalous Absorption of Ultrasonics in Nitrogen
Authors: Zmuda Alfred Joseph 
Published: September 2005

By means of the interferometer, the velocity and absorption of ultrasonic waves in nitrogen were measured at the frequency of 2.992 mc/sec, in the pressure range of 2.09 to 76 cm of Hg at a temperature of 29°C. A dispersion of velocity was found ranging from 354.3 meters/sec to 364.4 meters/sec. The ratio αexp/αclass dropped from 1.40 to 1.32, and the corresponding value of Cv/R dropped from 2.50 to 2.08.
Theoretical values for the change in velocity and in the absorption ratio, calculated by applying the equations for the exchange of energy between translational and vibrational degrees of freedom, show good agreement with the observed values. The increase in velocity and the decrease in αexp/αclass is interpreted as due to the slow exchange of energy between the translational and rotational degrees of freedom. The relaxation time for rotation was found to be 1.2×10−9 second.