摘要:

An infinitely long, perfectly flexible string is subjected to a transverse force that moves with arbitrary speed. The effect of the force accelerating through a resonant speed is determined. This invariably results in large deformations if the force is concentrated. With a distributed force, the deformations can remain small if the force accelerates through the resonant speed rapidly.

ISSN:0001-4966    

DOI:10.1121/1.1912775

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

An asymptotic solution is obtained for the end mode in a circular disk, using second‐order plate theory. Variation of end displacement with radius is indicated, and estimates of midpoints of the plateaus in the frequency spectrum are found. The results of a three‐dimensional elasticity solution are given for frequency and modal displacement and compare reasonably well with available experimental results.

ISSN:0001-4966    

DOI:10.1121/1.1912776

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Experiments are described which demonstrate that the frequency of different electronic oscillators can be independently controlled by electrode systems evaporated on a single quartz wafer. This arrangement can be used in several fields of applications, where the use of separate quartz wavers for the oscillators would imply errors due to temperature and other environmental differences.

ISSN:0001-4966    

DOI:10.1121/1.1912777

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

The effectiveness of one‐degree‐of‐freedom vibration isolation mounts is examined. It is shown that, at high frequencies where standing‐wave resonances occur in mounts and structural resonances occur in the machine and the foundation, there exists a functional lower bound of the mount effectiveness, regardless of machine and foundation impedance variations. This functional lower bound is obtained and its significance is discussed.

ISSN:0001-4966    

DOI:10.1121/1.1912778

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Propagation of ultrasound is investigated in an aqueous solution stratified by two solutes which diffuse at different rates. Both the finger interface and the diffusive interface are considered. Following correction for background absorption, edge effects, and refraction, attenuation of the order of 1.4 dB/cm is observed in the finger interface, while no attenuation is detected in the diffusive interface. The attenuation increases with frequency from 0.8 to 25 MHz. For higher frequencies, up to 42 MHz, the attenuation is constant. The loss is attributed to an as yet unspecified scattering mechanism.

ISSN:0001-4966    

DOI:10.1121/1.1912779

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

Sound pressure in the water under a point source overhead in air is shown by theory and experiment to propagate as from a virtual source situated (c1/c2) times the actual source height above the water and emitting unit‐distance sound pressure that is (2c1/c2) times the actual unit‐distance sound pressure, wherec1andc2are the speeds of sound in air and water, respectively.

ISSN:0001-4966    

DOI:10.1121/1.1912780

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP

摘要:

A number of materials having good acoustic absorption properties have been tested in order to determine their relative effectiveness in attenuating weak high‐frequency shock waves propagating atmospheric air. Weak shock waves with anN‐wave configuration of about 110‐μsec duration were generated by rifle bullets flying 2400 ft/sec over samples of acoustic material supported on a metal plate, and the details of the reflection of these waves at the surface of the various materials were monitored by using shadowgraph‐schlieren photographic techniques and pressure transducers. The urethane materials available gave a high amount of surface reflection compared to fiberglass materials of similar density. The least surface reflection was obtained with very low density (less than 1.0 lb/ft2fiberglass).

ISSN:0001-4966    

DOI:10.1121/1.1912781

出版商:Acoustical Society of America    

年代:1971

数据来源: AIP