Sound, physics travelling waves

Ultrasonic Spectroscopy. Information on size distribution maybe obtained from the attenuation of sound waves traveling through a particle dispersion. Two distinct approaches are being used to extract particle size data from the attenuation spectmm an empirical approach based on the Bouguer-Lambert-Beerlaw (63) and a more fundamental or first-principle approach (64—66). The first-principle approach implies that no caHbration is required, but certain physical constants of both phases, ie, speed of sound, density, thermal coefficient of expansion, heat capacity, thermal conductivity. 

What is the nature of the channel, the medium through which the power transmitted from the PK power generator reaches the target When I push down a key on my typewriter, the molecules of my skin serve as a channel for transmitting mechanical pressure from the muscles to the typewriter key. Some known physical energies, such as radio or light waves, require only space as a channel. Others require a physical medium for example, sound waves require air, water, or solids to travel. 

At its most fundamental level, acoustics deal with the physical production of sound waves, how they are modified and transmitted by various materials, and the effects these waves may have as they travel. Acoustical studies often include analysis of velocity, force, pressure, and other physical laws governing mechanical waves. 

---