[en] In this device the ambient background noise is unceasingly measured by means of piezoelectric pick-ups and is compared against a reference voltage in a comparator that controls the measuring instrument

[en] Basic terms of acoustic emission analysis are discussed. Some primary noise sources are mentioned, some aspects of application considered. (author)

No abstract available

[en] The application of statistical pattern recognition methods in Liquid Metal Fast Breeder Reactors surveillance is investigated. The study of the acoustic behavior of the sodium gives encouraging results as well in ''in situ'' experiment as in simulation test loop. 5 refs

[en] Scientific measurements of sound generation and radiation by musical instruments are surprisingly hard to correlate with the subtle and complex judgments of instrumental quality made by expert musicians

No abstract available

[en] During the latest expedition, one part of a three-leg international scientific cruise conducted earlier this year in waters about 480 km north of San Juan, Puerto Rico, Sandia engineers deployed 17 instrument packages - one of which was a wireless data communications system that successfully transmitted signals through 30 m of ocean-floor sediment and nearly 8 km of seawater. The wireless data system was contained in missile-shaped penetrators that fell to the ocean floor so they could gather information during the scientific expedition to help determine the feasibility of burying high-level radioactive wastes beneath the seafloor. Advantages of the new system are discussed

[en] The results of sounding of the atmospheric boundary layer (ABL) at a height of 240...700 m through an acoustic generator of a hail suppression system are presented. The spatial-temporal variability of the thin-layered structure of the ABL is shown

[en] Two sodium-immersed detectors, a microphone and an acoustic waveguide, have been developed, installed, and used for monitoring acoustic background of Experimental Breeder Reactor No. II (EBR-II). The microphone signal is free of structural resonances which appear in the signals from accelerometers mounted on the waveguide and various reactor components. Sound pressure level decreased by an order of magnitude when the primary sodium coolant flow was reduced from 100 percent to 50 percent. At full flow and independent of reactor power, the 1-millibar r.m.s. sound pressure as sensed by the sodium-immersed microphone had the characteristics of wideband noise over the frequency range 0.6 to 40 kHz. 7 references. (U.S.)

[en] A model-based approach is applied in the development of a processor designed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an adaptive, model-based processor embedded in a sequential likelihood detection scheme. The trade-off between state-based and innovations-based monitor designs is discussed, conceptually. The underlying theory for the innovations-based design is briefly developed and applied to a simulated data set