El urbanismo expansivo y la movilidad infantil en Cataluña

Los modelos de movilidad son una de las expresiones de las distintas formas urbanas. El urbanismo expansivo, como una de estas formas urbanas, está asociado a ciertos tipos de desplazamientos, relacionados a altos niveles de disfunciones sociales, económicas y medioambientales. La comunicación explora las tipologías de desplazamientos en un grupo ciudadano muy específico: los menores de 16 años. La población infantil tiene sus propias pautas de movilidad y estas están relacionadas, también, a las distintas formas urbanas. El análisis se basa en los datos que ofrece la Encuesta de Movilidad Cotidiana de Cataluña 2006 y de ella se analizan las grandes cifras para la comunidad catalana en conjunto. También se comparan los distintos subámbitos territoriales en relación a las características urbanas que estos presentan.

The minimum number of measurements for colour, sparkle, and graininess characterisation in gonio-apparent panels

Materials with new visual appearances have emerged over the last few years. In the automotive industry in particular there is a growing interest in materials with new effect finishes, such as metallic, pearlescent, sparkle, and graininess effects. Typically, for solid colours the mean of three measurements with repetitions is sufficient to obtain a representative measurement for colour characterisation. However, gonio-apparent panels have non-homogeneous colours, and there are no studies that recommend the minimum number of repetitions for colour, sparkle, and graininess characterisation of this type of panel. We assume that colour panels incorporating special-effect pigments in their colour recipes will require a higher minimum number of measurements than solid colour panels. Therefore, the purpose of this study is to verify this assumption by using a multiangle BYK-mac spectrophotometer, given that it is currently the only commercial device that can measure colour, sparkle, and graininess values simultaneously. In addition, a possible methodology is given for establishing the minimum number of measurements when characterising gonio-apparent materials using a specific instrument, able to be implemented in future instruments when determining multiple appearance attributes (colour, gloss, sparkle, etc.) for many coloration technologies. Thus, we studied the minimum number of measurements needed to characterise the colour, sparkle, and graininess of three types of sample with solid, metallic, and pearlescent coatings respectively. Twenty measurements were made at twenty random positions (different target areas) of 90 samples. The minimum number of measurements for all these variables was determined on the basis of the point at which the cumulative mean value became constant. Thus, applying new statistical tools, it is clearly shown that metallic and pearlescent panels require more colour measurements than solid panels, in particular when geometries are being measured in a specular direction. As regards texture (sparkle and graininess), more measurements are needed for graininess than for sparkle, and more for metallic panels than for pearlescent panels.