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Exact solutions are obtained for a model of the longitudinal displacement along an elastic tapered bar due to a force applied at its blunt end. A formula for velocity amplification is given; it specifies the velocity of the pointed end of the bar shortly after it feels the influence of the force. For a bar with an exponentially decreasing cross-sectional area, the velocity is magnified by twice an exponential function of length. This result has applications in the design of piezoelectric drills. In addition, we discuss the differences between the motions of rigid and elastic bars during the transient before one complete reflection of the wave induced by a force applied to an end of the bar. In this regime, force is proportional to velocity for elastic bars with constant cross-sectional areas. While the force-velocity relationship is more complicated for tapered elastic bars, their exact relationship is determined. [DOI: 10.1115/1.2424719]

A model has been developed for describing the stresses that arise during binder burnout in three-dimensional porous bodies. The pressure gradient that arises from the decomposition of binder in the pore space is treated as an equivalent body force. For input into the mechanics model, the pressure distribution is obtained from the analytical solution for three-dimensional porous bodies with anisotropic permeability. The normal and shear stresses are then calculated from finite element analysis for bodies of parallelepiped geometry. In general, the normal stresses occur at the center of the body and are an order of magnitude larger than the shear stresses. Both the normal and shear stresses depend on the body size, the body geometry, and on the permeability. [DOI: 10.1115/1.1460908]

Research describes the three-dimensional elasticity solutions of conical shell panel with cantilevered and clamped boundary conditons and its validation by convergence and comparison analysis. Data show that in conical shells, the frequencies of transverse bending modes increase with the increase in thickness.

An investigation of first-order Raman scattering of hexagonal GaN single crystal films deposited on sapphire substrate by low pressure metal organic chemical vapour deposition is presented. It was possible to obtain the temperature dependence of the five GaN Raman modes.

A study was conducted to analyze six nominal In(sub 0.48)(Ga(sub 1-x)Al(sub x))(sub 0.52)P layers prepared on GaAs(001). The quaternary alloy was prepared by low pressure metalorganic chemical vapor deposition turbo disk technology. A combination on nondestructive methods was utilized to understanding the growth parameters of the alloy. These include high resolution x-ray diffraction, atomic force microscopy and reflectance anisotropy.

A study was conducted to anlyze semiconductor wafers of both 4H-SiC and 6H-SiC using Raman spectroscopy. The Coherent Model INNOVA 90 Ar/Kr laser was utilized to record the Raman spectra at various spots on each wafer. Results indicated that the phonon-plasmon coupling of the AI(LO)phonon can be utilized as a carrier concentration measure. Findings also showed that Raman scattering of the phonon can be utilized as an in situ, noncontact diagnostic of doping uniformity in the manufacture of semiconductors.