THERMOELASTIC SURFACE WAVES OF AN ASSIGNED WAVELENGTH

Propagation of surface waves of an assigned wavelength on a theimoelastic half-space is considered. It is shown that there always exists a quasi-elastic and a quasi-thermal surface wave, both of which satisfying the adopted criteria for behavior at infinity. For each of them the wave is interpreted as a superposition of three dispersive inhomogeneous plane waves. The superposed waves have different directions of propagation and different phase velocities. Their directions of propagation are not parallel to the stressfree surface. The plane of constant amplitude that corresponds to each of the superposed waves is parallel to the stressfree surface and moves to it with constant velocity that is different for each of the superposed waves. Some numerical results are presented when the half-space is made of copper and thermally insulated.     

ENERGY-FLUX VECTOR OF SURFACE THERMOELASTIC WAVES

The energy-flux vector connected with the kinetic and internal energy of surface thermoelastic waves is considered. It is shown that this vector is not parallel to the surface of the half-space, as it is in classical elasticity. Its direction at a given point varies with the distance of this point from the surface. Its magnitude decays to 0 when this distance tends to infinity and decays exponentially to 0 in the direction of movement of the straight tine in which the planes of constant phase of the superposed waves intersect the surface of the half-space. Some numerical results are presented when the half space is made of copper and thermally insulated.     

Optical and structural characterization of Z-cut LiNbO/sub 3/ optical waveguides formed in a mixed proton source

In this paper, the optical and structural characteristics of Z-cut LiNbO/sub 3/ optical waveguides are experimentally investigated. The waveguides have been fabricated by fully immersing the samples in a closed beaker containing a mixture of benzoic and adipic acid at different concentration ratio. The influence of the dilution ratio on crystallographic phases, wavelength dispersion, diffusion coefficient, and index profile has been determined by using infrared absorption spectroscopy and optical characterization. The control of the thickness of guiding layers corresponding to /spl beta//sub 1/ and /spl beta//sub 2/ phases can be realized by varying the dilution ratio of the melt.     

The influence of the texture and surface properties of carbon adsorbents obtained from biomass products on the adsorption of manganese ions from aqueous solution

Studies on the adsorption of manganese ions from aqueous solution on carbon obtained from a mixture of biomass products indicate the importance of acidic surface oxides for manganese ion adsorption that is predominantly site specific. The results show that oxygen remaining from the raw material participates in the formation of surface oxides and indicates the possibility of controlling the content of acidic surface sites of the carbon surface by appropriate selection of the precursor composition and surface properties modification. The surface functionalities of oxidized carbon from a mixture of biomass products resembles the behavior of an ion-exchange resin. Oxidized carbon obtained from a 50:50 mixture of tar from steam pyrolysis of apricot stones and furfural contains a balance of surface area and high surface concentration of functional groups favorable for adsorption of positively charged manganese ions.