Colour changes in Galician granitic stones induced by UV Nd:YAG laser irradiation

Presentado en International Conference Lacona VII, Madrid, Spain, 17-21 September 2007[Resumen]: estudio sobre el cambio de color del granito gallego al limpiarlo mediante láser ultravioleta[Abstract] Laser cleaning has become a high profile and accepted specialized cleaning technique for most stone types. Given that local natural building stone in our region, Galicia (North West of Spain) is granite, our interest was focused on the response of this stone type to laser cleaning. The aim of this work is to determine the change in colour as index of the response of galician granites to UV-Nd:YAG laser exposure. For this purpose samples of commercial granites from different quarries were irradiated at increasing fluences. Colour changes were determined through the analysis of digital images and expressed in the L*a*b* and L*h*C* colour models. The results enable the establishment of application limits of laser cleaning to these material

Building granite characterisation, construction phases, mason’s marks and glyptography of Nossa Senhora de Guadalupe Church, Mouçós e Lamares, Galicia-North Portugal Euroregion

The Romanesque church of Nossa Senhora de Guadalupe of Mouçós e Lamares is located in Vila Real (North of Portugal). The exterior part of its nave is preserved almost unaltered. Most of the granite ashlars and corbels that make up this church have a mason’s mark in the centre of their faces. The building granites (Sanguinhedo and Vale das Gatas) have been identified and characterised petrographically and petrophysically. The mason’s marks have been as well identified; all the ashlars with visible mason’s marks have been mapped, and a glyptographic study has been carried out. In addition, the surface roughness of ashlars was measured. All these analyses have made it possible to locate the main historical quarry, to calculate the number of stonemasons who worked in the construction of the church, and to determine its construction phases. There are eight main types of mason’s marks on the nave façades. The quarrymen extracted the main building granite (Sanguinhedo granite) from the same quarry, or from nearby quarries. Although the most experienced stonemason has been identified, most stonemasons worked as a team during all construction phases of the church. Techniques such as petrography, ultrasonic P wave velocity, colourimetry, roughness and the determination of hydric properties will guarantee the quality and durability of the heritage stone for restorations. In addition, the glyptographic analysis revealed important historical and ethnographic findings that will be very useful for the appreciation of the monument. Therefore, the knowledge of built heritage, such as mason’s marks contribute to the conservation of historical quarries and traditions, as well as help understand the close cultural association societies have had with heritage stones. In this way, the scientific corpus of historical-cultural heritage can face for the development of tourism in Galicia-North Portugal Euroregion in a long-lasting sustainable way.info:eu-repo/semantics/publishedVersio

High performance n-channel organic field-effect transistors and ring oscillators based on C60 fullerene films

Published versio

Regeneración de campus para la creación de un laboratorio vivo de sostenibilidad ("living lab") en el Campus de Excelencia Internacional de Moncloa

La Universidad Politécnica de Madrid (UPM) a través de su Centro de Innovación en Tecnología para el Desarrollo Humano (itdUPM) está propiciando la generación de conciencia, conocimiento y soluciones innovadoras que contribuyen al cumplimiento de los Objetivos de Desarrollo Sostenible a través de un edificio que sirve como laboratorio de prueba para nuevas tecnologías verdes y como plataforma de ideación colaborativa y activación social

Compositional depth profiles of gilded wood polychromes by means of LIBS

[Resumen] Se analizan las diferentes capas existentes en retablos de maderas policromadas del periodo barroco. Se distinguen la capa base y las posteriores hasta el acabado mas superficial. Se aprecian las diferentes técnicas aplicadas en función de la procedencia y del autor que las ha realizado.[Abstract] Gilded wood polychromes are important artistic expressions in Galicia (NW Spain) during the baroque period. The variety of techniques applied in gilded ornamentation and the possible existence of products of previous interventions make difficult the restoration process of these artworks which frequently include the removal of a brass-based paint (purpurin) added to cover the lack of gold leaf. The aim of this work is the characterization by means of LIBS of the different layers in gilded wood polychromes. For this purpose small pieces taken from two baroque altarpieces were analyzed using a Nd:YAG laser source operating at the wavelength of 355 nm to obtain characteristic LIBS spectra and compositional depth profiles.Xunta de Galicia; PGIDIT06CCP00901C

Effect of processing temperature on the texture and shear mechanical properties of diffusion bonded Ti-6Al-4V multilayer laminates

Two multilayer materials based on Ti-6Al-4V alloy have been processed by diffusion bonding at two different temperatures [1023 K and 1173 K (750 °C and 900 °C)]. The influence of the processing temperature on microstructure, texture, and mechanical properties of the two multilayer materials has been analyzed. Scanning electron microscopy, X-ray diffraction, electron backscatter diffraction, and shear tests have been used as experimental techniques. The multilayer laminate processed at the lowest temperature of 1023 K (750 °C) exhibits mainly transversal texture in the longitudinal plane, which provides an anisotropic mechanical behavior, showing higher shear modulus and maximum shear strength under one of the shear test directions considered. In contrast, diffusion bonding at 1173 K (900 °C) leads to basal/transversal texture because of the partial α → β → α transformation, which provides more isotropic mechanical properties. Accordingly, this laminate shows similar shear modulus and maximum shear strength in different shear test orientationsFinancial support from MICINN (Projects MAT2009-14452 and MAT2012-38962)Peer reviewe

Regeneración de campus para la creación de un laboratorio vivo de sostenibilidad ("living lab") en el Campus de Excelencia Internacional de Moncloa

La Universidad Politécnica de Madrid (UPM) a través de su Centro de Innovación en Tecnología para el Desarrollo Humano (itdUPM) está propiciando la generación de conciencia, conocimiento y soluciones innovadoras que contribuyen al cumplimiento de los Objetivos de Desarrollo Sostenible a través de un edificio que sirve como laboratorio de prueba para nuevas tecnologías verdes y como plataforma de ideación colaborativa y activación social