Sound, propagation

The velocity of sound depends on the distances between the main-chain atoms and the intermolecular distances between the chains. In order to determine the orientation angle P from measurements of the sound velocity c in the fiber direction, it is necessary to know the sound velocities Cj and C perpendicular and parallel to a polymer sample with completely oriented chains  

The following procedure is adopted to determine the orientation angle. The velocity is either estimated or theoretically calculated. The velocity Cu is 

Consequently, an expression for the orientation factor/can be obtained from Equations (5-22) and (5-12). /can be determined from the sound velocity in the fiber and in the unoriented sample  

Wunderlich, Macromolecular Physics, Academic Press, New York, 3 Vols., 1973-1980. 

Spruiell and E. S. Clark, X-Ray Diffraction, in R. Fara (ed.), Polymers(= Vol. 16B of L. Marton and C. Marton (eds.-in-chieO, Methods of Experimental Physics), Academic Press, New York, 1980. 

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Besides simulation of the robot motion, a full virtual inspection includes simulation of the ultrasonic sound propagation during the inspection. For this purpose the UltraSIM/UlSim simulation module is used. 

In UltraSIM/UlSim the ultrasonic sound propagation from a virtual ultrasonic transducer can be simulated in ray tracing mode in any isotropic and homogeneous 3D geometry, including possible mode conversions phenomenons, etc. The CAD geometry for the simulation is a 3D NURBS surface model of the test object. It can be created in ROBCAD or imported from another 3D CAD system. 

The virtual transducer can be placed in a specific location on the test object surface, it can be moved along a path (e.g. a robot scanning path generated off-line or a path resulting from a real inspection sequence) or it can be moved along the surface, dynamically updating the ultrasonic sound propagation in the material. 

An ultrasonic horn has a small tip from which high intensity ultrasound is radiated. The acoustic intensity is defined as the energy passing through a unit area normal to the direction of sound propagation per unit time. Its units are watts per square meter (W/m2). It is related to the acoustic pressure amplitude (P) as follows for a plane traveling wave [1]. 

Lindsay, R. B. (1982). Relaxation processes in sound propagation in fluids a historical survey. In Physical acoustics XVI (ed. W. P. Mason and R. N. Thurston), pp. 1-36. Academic Press, London. [76, 77]... 

Ultrasonic Pressure Transducers. Advantage is taken of the fact that pressure influences sound propagation in solids, liquids, and gases, but in different ways. In solids, applied pressure leads to so-called stress-induced anisotropy, In liquids, the effects of pressure are usually small (relative to effects in gases), but the frequency of relaxation peaks can be shifted significantly,... 

Bassam Z. Shakhashiri, "Rela- tive Velocity of Sound Propagation Musical Molecular Weights,"... 

The laws of sound propagation in different media include the concept of ether, which is the hypothetical bearing substance of fight and electromagnetic waves. 

Moreover, v is the fluid velocity, pf and p, are the density and the viscosity of the fluid, respectively (f) and K are porosity and permeability of the core c/.,s are specific heat of the fluid and of the solid respectively Cfast>siow are the sound propagation speed of the fast and slow waves I fast,slow are the intensities of the fast and slow waves, while a.fast,siow are their damping coefficients. We use an effective medium approach for the liquid, describing the effect of the acoustic waves as source terms. There are two source terms. First there... 

Thus, microwave-induced sound is a function of sound propagation speed (v), and the radius (a) or circumference (27Ta) of the head. Figure 5 illustrates measured cochlear microphonic frequency in cats and guinea pigs (8,1.5) and calculated fundamental sound... 

Akulichev, V.A., Bulanov, V.N. 1982. Sound propagation in a crystallizing liquid. Sov. Phys. Acoust. 27, 377-381. 

In an acoustic sense a material is fully characterised by four parameters the longitudinal and transverse sound speeds, and the longitudinal and transverse sound absorption. We shall successively discuss sound propagation and sound absorption. 

So the Poisson ratio plays an important part in sound propagation. 

TABLE 14.1 Sound propagation and elastic parameter data for various polymers... 

If sound propagation is considered as a reversible adiabatic process, we can use Eq. (19) to obtain for a perfect gas... 

The basic concepts and definitions relating to sound propagation in a lossy material are reviewed. The material may be a viscoelastic polymer which converts the sound energy to heat by molecular relaxation, or the material may be a composite where sound is scattered by inhomogeneities (inclusions) in a host matrix material. 

The discussion which follows, of sound propagation in a lossy material, is limited to the linear case. That is, it is assumed that the stress-strain relation in the lossy material is linear. In this case a plane, harmonic sound wave propagating through the lossy material decays exponentially with distance [3],... 

A second mechnism for sound attenuation is mode conversion. The sound waves in air or water are longitudinal waves, where the particle motion is parallel to the direction of sound propagation. With appropriate boundary conditions the longitudinal deformation can be converted to shear deformation or to viscous flow. Conversion to viscous flow is most readily achieved at... 

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