Refraction (sound) Refraction (sound) Refraction, in acoustics, comparable to the refraction of electromagnetic radiation, is the bending of sound propagation trajectories (rays) in inhomogeneous elastic media (gases, liquids, and solids) in which the wave velocity is a function of spatial coordinates. Bending of acoustic rays in layered inhomogeneous media occurs towards a layer with a smaller sound velocity. This effect is responsible for guided propagation of sound waves over long distances in the ocean and in the atmosphere. In the atmosphere, vertical gradients of wind speed and temperature lead to refraction. The wind speed is usually increasing with height, which leads to
A-235 anti-ballistic missile system A-235 and the A-135 missile defense system [6]. According to foreign media reports, on November 18, 2015, the first successful launch of the Nudol missile and the third launch in the missile test program of the complex took place. Presumably, the deployment site of the A-235 missile defense system will be the former base area of the A-135 missile defense system near Moscow. According to the plan, the complex will have the capabilities to intercept the warheads of ballistic missiles, as well as spacecraft [4]. In May 2016, system elements were tested as part of the exercises of the Military