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[en] Transparent and conducting films of mixed oxides of zinc and zirconium have been prepared by sol-gel method. The amount of zirconium have been varied in between 0 to 3 at.%. XRD patterns showed that the nature of films are polycrystalline but the preferred orientation changes from (1 0 0) to (1 0 1) and finally (0 0 2) with increasing amount of Zr doping. The morphology and crystallite size of the films are strongly dependent on the doping concentration. The resistivity decreases with doping concentration up to 1.5 at.% but increases with concentration more than that. The maximum carrier concentration is (∼10¹⁹ cm^-3) and the mobility is minimized at this doping concentration. The optical bandgap was estimated from the reflectance and transmittance spectra. The obtained optical bandgap is about 3.3 eV, for unstrained ZnO but slight shrinkage in bandgap is noticed up to 2 at.% doping. There is corresponding rise in width of band tail which is a measure of the disorder in the system

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[en] The state of stress in a reactor containment shell with large openings (e.g. equipment hatch, personnel lock, etc.) can be readily determined using available analytical-numerical techniques if the usual assumptions of elastic, isotropic material could be justified. However, a conventionally reinforced concrete containment structure will crack when subjected to design thermal and mechanical loads and will consequently fail to satisfy this assumption. Cracking in concrete results in different membrane and bending stiffnesses (hence split-rigidity) which vary with the depth of cracking. Based on these stiffnesses the shell is considered to have an equivalent reduced membrane thickness tsub(m) and a bending stiffness tsub(B). Using a similar approach to that for analyzing stiffened shells these effective thicknesses are incorporated in the governing differential equations to yield the following shell characteristic parameters for the cracked section case. (orig.)

[en] The oxidation states of tin in pure foils and compressed powders of tin oxides were determined from shifts in the principal Auger transitions of 3 +- 1 eV for tin in SnO and 7 +- 1 eV for tin in SnO₂. Moreover, SnO powder is reduced to tin and oxygen during prolonged periods of bombardment with argon ions whereas similar effects are not observed for SnO₂, and examination of the oxidation states of tin in pure tin foils exposed to dry oxygen at 200⁰C reveals that SnO is uniquely formed at the external surface during early stages of annealing and gradually decreases in concentration as a function of increasing depth. The last results are confirmed by transmission electron microscopy, which also indicates that both SnO and SnO₂ are formed during prolonged annealing at 200⁰C. (Auth.)

[en] The paper presents a methodology for evaluating the local damage (missile penetration and backface barrier damage) of a reinforced concrete barrier impacted by a non-deformable missile. An interface force-time history and barrier failure mechanism are developed, using available experimental data. These methods are extrapolated to the case of turbine missiles which are characterized by large dimensions and high impact velocities outside the range of available data. (orig.)

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