Depth of thermal penetration in straight grinding

Unlike the usual numerical FEM approach to determine the thermally affected layer during the grinding process, we propose a simple analytical approach to estimate the depth of thermal penetration. For this purpose, the one-dimensional definition of depth of thermal penetration is applied to the two-dimensional heat transfer models of straight grinding. A method for computing the depth of thermal penetration in these two-dimensional models is derived and compared to the one-dimensional approximation. For dry grinding, it turns out that the one-dimensional approximation is quite accurate when we consider a moderate percentage in the temperature fall beneath the surface, regardless the type of heat flux profile entering into the workpiece (i.e., constant, linear, triangular, or parabolic). In wet grinding, the latter is true if we consider a constant heat flux profile and a high Peclet number, i.e., Pe > 5. Finally, the one- and two-dimensional approaches calculating analytically the depth of thermal penetration have been compared to the temperature field numerically evaluated by a three-dimensional FEM simulation given in the literature, obtaining a quite good agreement

Estudio crítico de los índices de severidad y la superficie afectada por el incendio de Sierra de Luna (Zaragoza)

Para la determinación del área quemada y la severidad asociada del incendio de Sierra de Luna (Zaragoza), ocurrido el 4 de julio de 2015, se han calculado tres índices espectrales derivados de Landsat-8: NDVI, NBR y BAI. Comparando los resultados obtenidos por cada uno de ellos, en un incendio con extensas zonas de cultivo entre zonas arboladas, se ha determinado que la combinación de ΔNBR y BAI mejora sustancialmente la determinación del área realmente quemada, tanto en su perímetro exterior como en las zonas aisladas no quemadas de su interior. Para el cálculo de la severidad, se propone una metodología basada en el análisis de las diferencias de NBR, antes y después del incendio, y su combinación con el BAI, en función del valor previo al incendio de los índices NBR y de NDVI

Depth estimation improvement in 3D integral imaging using an edge removal approach

A new depth estimation method for 3D reconstruction in a synthetic aperture integral imaging framework is presented. This method removes the edges of the objects in the elemental images when the objects are in focus. This strategy aims to compensate for the noise that objects focused close to the cameras can introduce into the photo-consistency measure of objects at higher depths. Furthermore, a photo-consistency criterion is applied combining a defocus and a correspondence measure, and a depth regularization method which smooths noisy depth results for the case of object surfaces. The proposed method obtains consistent results for any type of object surfaces as well as very sharp boundaries. Experimental results show that our method reduces the noise in the object edges and gives rise to an improvement in the depth map results in relation to the other methods shown in the comparative analysis