Results 221 to 230 of about 103,759 (256)

A Smooth Type of Cosmic Noise Absorption

Nature, 1964
RIOMETER investigations on auroral absorption events have been carried out so far by various experimenters in Alaska1, Canada2 and Scandinavia3. The characteristics of the auroral type of riometer absorption are normally given as follows: Auroral absorption is associated with the occurrence of visible aurora and magnetic disturbances.
J. ORTNER, W. RIEDLER
openaire   +1 more source

Absorption of sound by noise in one dimension

The Journal of the Acoustical Society of America, 1996
Experimental results are presented for the excess attenuation of monofrequency waves in the presence of high-intensity noise in one dimension. The theory by Rudenko and Chirkin predicts a Gaussian attenuation of a weak signal in the presence of shockless noise, thus showing that in one dimension translational invariance has been broken.
Andrés Larraza, Bruce Denardo, Anthony Atchley   +2 more
openaire   +1 more source

Active Resonators for Noise Absorption

Journal of Vibration and Acoustics, 2005
Abstract Active control is applicable to resonators to improve noise control performance. Many active resonators depend on transfer functions from secondary sources to sensors to generate destructive interference in noise fields. These transfer functions are sensitive to the variance of acoustical parameters in noise fields where the ...
openaire   +1 more source

Absorption of sound by noise in one dimension

The Journal of the Acoustical Society of America, 1993
A special case of a prediction by O. Rudenko and A. Chirkin [Sov. Phys. JETP 40, 945–949 (1975)] is that a small-amplitude monofrequency sound wave will decay as a Gaussian as a result of interaction with finite-amplitude noise, if the waves are all moving in one direction. An experiment to verify this will be discussed.
Bruce Denardo, Andrés Larraza, Anthony A. Atchley, Steven Dorff   +3 more
openaire   +1 more source

Cosmic noise absorption pulsations

1973
The fast cosmic noise absorption (c.n.a.) pulsations observed with fast response riometers at Macquarie Island in the southern auroral zone are discussed in relation to the parameters of the lower ionosphere. The pulsations which are similar to and associated.
openaire   +1 more source

Composites with improved absorption of noise and vibration

Russian Engineering Research, 2017
© 2017, Allerton Press, Inc. The development of composites based on thermosetting resins with improved vibration and noise absorption is considered. Mathematical and topological models are proposed to describe the influence of the composition on the vibration and noise absorption and elastic properties of the composites. The composition of filled epoxy,
Grechishnikov V., Gumerov I., Gumerov M., Lakhno A., Shafigullin L., Yurasov S., Shafigullina G., Voronenko V.   +7 more
openaire   +3 more sources

Absorption of sound by noise in one dimension.

The Journal of the Acoustical Society of America, 1992
Experimental results are presented for the excess attenuation of mono- frequency waves in the presence of high-intensity noise in one dimension. The theory by Rudenko and Chirkin predicts a Gaussian attenuation of a weak signal in the presence of shockless noise, thus showing that in one dimension translational invariance has been broken. The theory is
Andrés Larraza, Bruce Denardo
openaire   +1 more source

Absorption and noise in x-ray phosphors

Journal of Applied Physics, 1973
When the signal in an x-ray image system is formed by integrating the scintillation pulses rather than by counting them, the signal-to-noise ratio is reduced by a factor which depends on the shape of the pulse-height distribution. The signal-to-noise ratio cannot be related directly to either quantum absorption or energy absorption, and a new quantity ...
openaire   +1 more source

Air absorption of motor vehicle noise

The Journal of the Acoustical Society of America, 1986
Expressions for A-weighted sound pressure and A-weighted sound exposure of a motor vehicle passby are derived. It has been assumed that geometrical spreading and atmospheric absorption are major factors, influencing propagation. The Doppler shift and convective changes of the source’s directivity, as results of motion, are analyzed.
openaire   +1 more source

Effects on roadside noise levels of sound absorptive materials in noise barriers

Applied Acoustics, 1999
Abstract There is considerable interest in the use of sound absorptive materials for reducing noise reflected from noise barriers although there is little reliable information on their effectiveness in practice. The primary object was to determine, under carefully controlled measurement conditions, the effects on roadside noise levels of applying ...
G.R. Watts, N.S. Godfrey
openaire   +1 more source