899 resultados para Economies of density
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This work describes the use of a large aperture PVDF receiver in the measurement of density of liquids and elastic constants of composite materials. The density measurement of several liquids is obtained with the accuracy of less than 0.2% using a conventional NDT emitter transducer and a 70-mm diameter, 52-μm P(VDF-TrFE) membrane with gold electrodes. The determination of the elastic constants of composite materials is based in the measurement of phase velocity. It is shown that the diffraction can lead to errors around 1% in the velocity measurement when using a pair of ultrasonic transducers (1MHz and 19mm diameter) operating in transmission-reception mode separated by a distance of 100 mm. This effect is negligible when using a pair of 10-MHz transducers. On the other hand, the dispersion at 10 MHz can result in errors of about 0.5%, measuring the velocity in composite materials. The use of an 80-mm diameter, 52-μm thick PVDF membrane receiver allows measuring the phase velocity without the diffraction effects.
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The present work aimed at characterizing geological features that identify areas with high ruptibility (fracturing) in the Osvat/Osplan pipeline in São Sebastião, São Paulo. The analysis of ruptile geological structures (lines of strikes and structural lineaments) through the use of orbital remote sensing was used as systematic mapping. The analysis of these features enables the inference of factors, such as permeability, infiltration and degree of shear in the region, factors which influence the processes of erosion and landslides in the area. On the map of structural lineaments, points of lineaments intersection from different directions were analyzed, followed by the counting of the frequency of these items per unit area, allowing the statistical modeling of spatial distribution, generating the map of density of structural lineament intersections, which allows determining areas with the highest percolation of fluid in the rock structure. However, on the map of lines of strikes, a space analysis was conducted to identify the two directions with higher frequency of lines of strikes in order to establish the maximums 1 and 2 and to identify the areas of abrupt changes of direction of these strike lines. In such areas where abrupt changes of directions of maximum lines of strikes occur, consequently there will be intense percolation of fluids, responsible for higher alterability of the rock/soil complex, facilitating the installation of erosion processes and landslides, increasing the area instability and consequently the vulnerability of the pipeline.
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Includes bibliography