1,792 research outputs found
Control of acceleration in sine/random vibration tests
Sampling output levels of accelerometers using largest output or any combination of outputs provide control of shaker for spacecraft vibration qualification tests
Automatic Gaussian random-noise limiter
Circuit limits the positive and negative peaks of a random-noise signal. It accurately establishes a known limiting level relative to any given RMS value of the random-noise signal input
Gated compressor, distortionless signal limiter
Comparator/multiplier arrangement is capable of limiting input power to voice coil so that desired maximum current level is never exceeded. Overall test system consists of signal source which produces frequency spectrum required for acoustic test, gated compressor circuit, and power amplifier feeding transducer
Spectral analysis applied to a digitally coded PM RF carrier
Spectral analysis applied to digitally coded phase modulated radio frequency carrie
Apparatus for scanning the surface of a cylindrical body
A laser scanning system for providing a two-dimensional display of a cylindrical surface, such as to display striae of a fired bullet is described. The cylinder is scanned along its axis by vibrating one mirror in the laser beam path, and is scanned in a direction normal to its axis by vibrating a second mirror in a direction normal to the first or by rotating the bullet. Scan control signals are adjusted in phase to produce a synchronized display of a video signal obtained from detection of scattered light from the surface thus scanned by a laser beam
Digital decorrelator saves time and expense in acoustic testing of structures
Instantaneous signals from coherent random sound field are summed and time delayed to avoid introducing vectorial addition errors. Resultant statistically independent signals are applied to spectrometer. Displayed sound pressure level is proportional to square root of sum of squares of sound pressure levels taken over frequency range of interest
Market Definition
We explain the “hypothetical monopolist test” that has become the standard methodology for identifying relevant antitrust markets in merger cases, and discuss two approaches to implementing the test. We then focus on the implementation of the test when firms offer multiple products or services, either inside or outside the candidate market, and discuss the “hypothetical cartel test” introduced in the 2010 U.S. Merger Guidelines
Local control of crows by trapping
THE common crow seen frequently around farms in the South-West is the raven (Corvus coronoides) whilst the pest of pastoral areas is the true Australian crow (Corvus cecilae).
Farmers and pastoralists, although recognising the importance of these birds as scavengers and destroyers of insects, particularly grasshoppers, sometimes for one reason or another, wish to reduce their numbers over a localised area.
Baiting with phosphorus has been used in the past, but the purpose of this article is to describe and illustrate a type of trap which has become universally known as the Australian Crow Trap
Standard environmental testing practices
Manual on procedural requirements for performing certain environmental tests on space flight equipment provides information for test equipment designers, quality control and production engineers. Contents of manual are summarized
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