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Probing the atmosphere with infrasound
The Physics Teacher, 1979Recently there has been increased interest in weather conditions in the upper atmosphere. This has been due to interest in the effects of ozone depletion in the upper atmosphere, and recognition that sunspot activities probably affect climate by changing the energy balance in the upper atmosphere in subtle ways.
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On Infrasound Waveguides and Dispersion
Seismological Research Letters, 2009Waveguides are structures that provide for efficient propagation of waves. One of the earliest applications of a waveguide is the speaking tube, which was used on ships. Propagation in some waveguides leads to dispersion, a phenomenon in which the phase velocity depends on the frequency.
Eugene Herrin, Petru T. Negraru
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The Journal of the Acoustical Society of America, 2012
The generation of infrasound from the pulsation of compressed air is examined analytically and experimentally to explore the aerodynamic physics as well as engineering implementations. Several model experiments were developed and utilized to explore the problems associated with this approach.
Charles M. Slack +4 more
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The generation of infrasound from the pulsation of compressed air is examined analytically and experimentally to explore the aerodynamic physics as well as engineering implementations. Several model experiments were developed and utilized to explore the problems associated with this approach.
Charles M. Slack +4 more
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Microseism and infrasound generation by cyclones
The Journal of the Acoustical Society of America, 2003A two-dimensional cylindrical shear-flow wave theory for the generation of microseisms and infrasound by hurricanes and cyclones is developed as a linearized theory paralleling the seminal work by Longuet-Higgins which was limited to one-dimensional plane waves. Both theories are based on Bernoulli’s principle.
Vassilios Fessatidis +4 more
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Infrasound Monitoring for Atmospheric Studies
2009The infrasound field, the science of low-frequency acoustic waves, has developed into a broad interdisciplinary field encompassing academic disciplines of physics and recent technical and scientific developments. The infrasound network of the International Monitoring Network (IMS) of the CTBT-Organization has demonstrated its capability for detecting ...
Le Pichon, Alexis +2 more
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Detecting and characterizing infrasound signals with optical fiber infrasound sensors
The Journal of the Acoustical Society of America, 2005Optical Fiber Infrasound Sensors (OFIS) are long compliant tubes wrapped with two optical fibers that interferometrically measure the differential pressure variation along the length of the tube. Because each sensor averages spatially along the length of the tube, the frequency response of the recorded pressure variation is a function of the ...
Michael A. H. Hedlin +4 more
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Infrasound-convection instability.
The Journal of the Acoustical Society of America, 2010Heated below temperature stratified atmospheric layer is unstable and convection flow can be developed in such an area. Convection happens because warm less dense air goes up while cooler air comes down. Infrasound can initiate convection flow and being amplified by the flow. The process of infrasound-convection interaction is considered in the present
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The Journal of the Acoustical Society of America, 2020
Infrasound is formally defined as sound at frequencies of 20 Hz and below. Because of low atmospheric absorption, infrasound canpropagate thousands of km or more with minimal attenuation. Ray methods are effective in characterizing long-range infrasound propagation, in particular for predicting acoustic paths and identifying dominant ducting mechanisms.
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Infrasound is formally defined as sound at frequencies of 20 Hz and below. Because of low atmospheric absorption, infrasound canpropagate thousands of km or more with minimal attenuation. Ray methods are effective in characterizing long-range infrasound propagation, in particular for predicting acoustic paths and identifying dominant ducting mechanisms.
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On tropospheric ducting in infrasound.
The Journal of the Acoustical Society of America, 2009Infrasound can propagate to ranges of many hundreds of km. Signals received on the ground at ranges of 200 km or more have propagated high into the atmosphere through the stratosphere and thermosphere. At shorter ranges, the propagation is dominated by structure in the lower atmosphere such as the jet stream and the atmospheric boundary layer ...
Roger Waxler, Philip Blom
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The Journal of the Acoustical Society of America, 1973
The AMRL dynamic pressure chamber (a hydraulic device that produces intense infrasound) recently became operational. Preliminary to human whole body exposures, a variety of experiments with animals are being performed in order to evaluate physiological limits.
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The AMRL dynamic pressure chamber (a hydraulic device that produces intense infrasound) recently became operational. Preliminary to human whole body exposures, a variety of experiments with animals are being performed in order to evaluate physiological limits.
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