A model for the acoustic production of gravitational waves at a first-order phase transition is presented. The source of gravitational radiation is the sound waves generated by the explosive growth of bubbles of the stable phase. The model assumes that the sound waves are linear and that their power spectrum is determined by the characteristic form of the sound shell around the expanding bubble...

We consider MHD waves as a heating source of cool cores of galaxy clusters. In particular, we focus on transverse waves (Alfvén waves), because they can propagate a longer distance than longitudinal waves (sound waves). Using MHD simulations, we found that the transverse waves can stably heat a cool core if the wave period is large enough (& 10 yr). Moreover, the longitudinal waves that are cre...

purpose is to reduce the unwanted noise from recorded bird sound chip notes, design a scheme to detect differences and similarities between recorded chip notes, and classify bird sound chip notes. The technologies of determining the similarities of sound waves have been used in communication, sound engineering and wireless sound applications for many years. Our research is focused on the simila...

We report the discovery of ripple-like X-ray surface brightness oscillations in the core of the Centaurus cluster of galaxies, found with 200 ks of Chandra observations. The features are between 3 to 5 per cent variations in surface brightness with a wavelength of around 9 kpc. If, as has been conjectured for the Perseus cluster, these are sound waves generated by the repetitive inflation of ce...

It is shown that the Ocean-Earth crust interface can propagate gravity-sound Rayleigh waves. Dispersion properties of waves and flux of energy are derived. It is shown that the waves split into low and fast velocity branches. The fast branch has a multimode structure and has a cutoff in frequency and wave number. Numerical solutions are discussed.

Bowing a string with a non-zero radius exerts a torque, which excites torsional waves. In general, torsional standing waves have higher fundamental frequencies than do transverse standing waves, and there is generally no harmonic relationship between them. Although torsional waves have little direct acoustic effect, the motion of the bow-string contact depends on the sum of the transverse speed...

abstract background: given the fact of irrecoverable consequences of noise in industrial societies and the environment, acoustic filter (silencer) is an instrument which obstacles the transmission of sound waves. a sort of this silencer is helmholtz resonator (branch amplifier) which comes to sound appropriate for low and below 200 hz frequencies in fan and channel noise. the purpose of this ar...