[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] In the Arctic, warming and concomitant reductions in sea ice will affect the underwater soundscape, with the greatest changes likely being linked to anthropogenic activities. In this study, an acoustic recorder deployed on an oceanographic mooring in western Fram Strait documented the soundscape of this area, which is important habitat for the Critically Endangered Spitsbergen bowhead whale population. The soundscape was quasi-pristine much of the year, with low numbers of ships traversing the area. However, during summer/autumn, signals from airgun surveys were detected > 12 h/day. Mean received peak-to-peak SPLs for loud airgun pulses reached 160.46 ± 0.48 dB 1 μPa when seismic-survey ships were close (at ~ 57 km). Bowhead whales were present almost daily October–April in all years, with singing occurring in almost every hour November–March. Currently, loud anthropogenic sound sources do not temporally overlap the peak period of bowhead singing. This study provides important baseline data for future monitoring. - Highlights: • At present, underwater sound levels in western Fram Strait are low to moderate (< 60 dB). • Shipping activity is low, but seismic surveys occur nearby in summer/autumn. • Critically endangered bowhead whales are present in the area throughout most of the year. • Currently, little human activity overlaps with bowhead winter occurrence.

[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] This overview of the uses of sodars in meteorological applications categorizes the applications by signal source, specifically amplitude, frequency, or ''visualization'' for example, of vertical time sections of signal amplitude. Examples are shown of data derived from each category. A final section presents the potential for using groups of sodars in networks with other instruments to estimate quantities such as divergence

[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