| The Mean of the Field for Cylindrically Spreading Waves in a Random Medium. |
APR 1974 |
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| Authors:
M. M. Fitelson; GENERAL ELECTRIC CO SYRACUSE NY HEAVY MILITARY EQUIPMENT DEPT
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 | The mean value of the field for cylindrically spreading waves in a random medium is obtained when forward scattering is domiant. In addition, the region of validity of the solution is obtained. These results are identical to the corresponding results for plane waves, except for cylindrical spreading loss. (Author) |
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| Application of Acoustic Surface Wave Devices to Low Probability of Intercept Communications. |
DEC 1973 |
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| Authors:
John E. Geist; Theodore J. Klein; Paul F. Sass; ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ
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| Recent progress in Acoustic Surface Wave Device Technology has resulted in the availability of many techniques for signal processing, which were heretofore impractical, due to size requirements of conventional delay lines. Surface Wave Devices may now enable the Army to realize practical implementations of many interesting techniques, such as spread spectrum communications. This report surveys present capabilities in this field and investigates a particularly interesting application of surface wave devices ... |
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| Normal Modes for a Translating Open-Ended Cylindrical Cavity, |
06 AUG 1969 |
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| Authors:
Bernard Brown; Louis F. Libelo; NAVAL ORDNANCE LAB WHITE OAK MD
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| The effect of motion on the normal modes and wave patterns of a rigid open-ended right circular cylinder translating at constant velocity along its axis through an elastic medium was studied. Solution of the wave equation, in cylindrical coordinates, for small amplitude harmonic disturbances in a homogeneous, linear, irrotational elastic medium was effected within the moving boundaries. The solutions yield the resonant frequencies and the changes in the nodal patterns ... |
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| Fluids for Acoustic Lenses. |
AUG 1969 |
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| Authors:
Gordon R. Leader; Arnold H. Fainberg; Robert L. Atwell; J. R. Soulen; PENNWALT CORP KING OF PRUSSIA PA CORPORATE RESEARCH AND DEVELOPMENT
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| The velocity of sound in a number of liquids and liquid mixtures, mainly organic compounds containing fluorine, was measured at 0, 20, and 40C. Densities were also obtained, and values of acoustic impedance and temperature coefficients of sound velocity were calculated. (Author) |
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| AN ACOUSTIC, HIGH-RESOLUTION, SEDIMENT PROFILER. |
15 NOV 1966 |
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| Authors:
A. Johansen; SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)
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| An acoustic sediment profiler is described that utilizes short 50 kHz pulses to achieve a high range resolution. In trials in shallow water, penetration depths of about 9 m and resolution of about 25 cm were obtained. Suggestions for improvements and for its adaptation to a deep water version are included. (Author) |
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| INSTRUMENTATION FOR ACOUSTIC AND VIBRATION MEASUREMENTS. |
01 JAN 1966 |
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| Authors:
Robert York Chapman; NAVAL SUBMARINE BASE NEW LONDON CONN ACOUSTICAL RESEARCH AND DEVELOPMENT DIV
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| This technical report contains operational procedures for the General Radio Sound Level Meter Type 1551-B/C, Endevco Accelerometer and Control Box Type 1560-P13, Sound and Vibration Analyzer Type 1564-A, Graphic Level Recorder Type 1521-A, Vibration Calibrator Type 1557-A and the Strobotac Electronic Stroboscope Type 1531-A. These instruments manufactured by the General Radio Company are presently authorized for SS(N) and FBM Class Submarines. The intent of this report is to publish, in ... |
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| COMPARISON OF THE SEMIAUTOMATIC AUDIOMETER WITH MANUAL AUDIOMETRY. |
DEC 1965 |
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| Authors:
Francis A. Brogan; James E. Endicott; SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TX
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| Semiautomatic audiometry (utilizing 5 dB per step attenuation) and manual audiometry are compared. Apparatus and test results indicate that mean thresholds and the mean test time for the two methods are in close agreement. A remote readout method is described that simplifies installation for two-room test situations. (Author) |
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| ACTIVE ACOUSTIC DEVICES. |
MAY 1965 |
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| Authors:
N. G. Sakiotis; W. H. Brendecke; F. S. Hickernell; MOTOROLA INC PHOENIX ARIZ SEMICONDUCTOR PRODUCTS DIV
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| Investigations of suitable heat sink material needed for CW operation resulted in the development of a BeOloaded epoxy with a thermal conductivity of 1.6 BTU/HrFt-degrees F. This appears compatible with the requirements as previously determined. The open-tube or dynamic technique was determined to be the most feasible for the epitaxial growth of CdS transducers. Theoretical and experimental investigations of the vacuum deposition of CdS resulted in films with resistivity values ... |
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| BAFFLED PISTON RADIATOR: EXPANSION OF POTENTIAL IN FAR, PARAXIAL FIELD. |
1965 |
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| Authors:
Martin Greenspan; NATIONAL BUREAU OF STANDARDS WASHINGTON D C INST FOR BASIC STANDARDS
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| AN ACOUSTIC SYSTEM FOR RELEASING SUBMERGED OCEANOGRAPHIC BUOYS FROM THEIR ANCHORS ON DEMAND USING A 1.4 KC COMPACT SOURCE. |
01 DEC 1963 |
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| Authors:
R. Frassetto; R. Pesaresi; SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)
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| The paper describes an anchor-releasing device for the recovery of moored oceanographic equipment. The releaser is actuated by a remote acoustic signal emitted by a small and powerful 1400 cps sound source rather than by unsafe explosive charges. The acoustic power output of the source can be regulated according to the range of operation, up to a maximum of 400 watts. The submerged unit is self-contained, remains active for several ... |
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| AN ACOUSTIC ARRAY SIMULATOR, |
01 NOV 1963 |
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| Authors:
Victor C. Anderson; W. R. Cherry; SCRIPPS INSTITUTION OF OCEANOGRAPHY SAN DIEGO CALIF MARINE PHYSICAL LAB
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| An acoustic array simulator is an apparatus which generates synthetic sea noise and target information as electrical waveforms. It provides a means of evaluating the general performance of beamforming equipment without a hydrophone array. Although the simulator described was built to simulate a particular array, the design principle incorporated provides a versatility enabling its use with many different array configurations. This report discusses in detail the generation of the sea ... |
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