João Pedro Veiga

The Chalcolithic period in the Lisbon region, Portugal, is usually divided into three phases chronologically: the Early Chalcolithic, characterized by cylindrical corrugated cups, Full Chalcolithic by so-called acacia-leaf decoration, and Late Chalcolithic by Bell Beaker pottery. The aim of this research is to determine if Chalcolithic ceramic raw materials and production techniques have remained the same over time and whether the pottery is locally produced. Regarding the Lisbon region, 149 ceramic samples from four Chalcolithic settlements (Vila Nova de São Pedro, Penedo do Lexim, Espargueira and Baútas) were evaluated concerning textural, chemical and mineralogical compositions. Textural analysis was performed using optical microscopy, chemical characterization was achieved using micro-energy dispersive X-ray fluorescence spectrometry and mineralogical characterization was undertaken using X-ray powder diffraction and petrographic microscopy as main techniques. Results suggest that production techniques may have remained similar throughout all the Chalcolithic period, with firing temperatures between 700 and 800 °C. Multivariate analysis of results from chemical and mineralogical analyses suggests that multiple sources of raw materials must have been used in the manufacture of the pottery collected at the four Chalcolithic settlements.

© 2016, Springer-Verlag Berlin Heidelberg.The glaze and in-glaze pigments of the historical nineteenth-century glazed tiles from the Pena National Palace (Sintra, Portugal) were characterized using a multi-analytical approach. Chemical composition and microstructural characterization were ascertained by µ-PIXE, µ-Raman, optical microscopy and VP-SEM–EDS. The manufacturing technique and colour palette in these tiles were found to be close to the ceramic pigments used in traditional majolica. The blue and purple colours derive from cobalt oxide and manganese oxide, respectively. A mixture of Pb–Sn–Sb yellow with cobalt oxide and iron oxide was used for green and dark yellow, respectively, while grey tonalities consist of a complex mixture of cobalt oxide, manganese oxide and Pb–Sn–Sb yellow in different proportions. Results obtained allowed the determination of the oxides and elements used in pigments as well as production techniques, resorting to traditional majolica manufacture, although the tiles were produced by the end of the nineteenth century.

Bluish-grey limestones have been extensively used as ornamental stones for decoration purposes in buildings, as well as in works of art, and accordingly, have been the target of intense exploration. In Portugal, the Jurassic limestone massif known as the Maciço Calcário Estremenho (MCE), has been the source of grey-coloured ornamental stones, namely the Azul Valverde (one of the most well-known bluish-grey limestones) and Atlantic Blue varieties, both of which may undergo colour changes in outdoor environments. In this sense, it is important to understand the sudden colour change from bluish-grey to yellow/beige in the same limestone block in a quarry, or even, what happens to the colour when polished limestone is placed outdoors. This study was undertaken using various techniques, namely XRF (X-ray fluorescence spectrometry), XRD (X-ray diffraction), SEM (scanning electron microscopy), DTA–TG (differential thermal analysis/thermogravimetry) and colourimetry. Synchrotron radiation was also used at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) where XANES (X-ray Absorption Near Edge Structure) spectra at Fe K-edge were collected to ascertain the speciation state of Fe in different coloured zones of the limestone, previously checked by EDXRF (energy dispersive X-ray fluorescence). The presence of Fe2+ and Fe3+ are responsible for the greyish and yellow/brown colour, respectively. On the other hand, the UV radiation from the sun causes a quickened and severe bleaching/fading on the dark blue/grey polished limestone.

Sol-gel production of hybrid materials has, to some extent, revolutionised materials’ engineering and the way science and technology perceive the creation of new materials. Despite that, the method presents some limitations that are circumvented by radiation processing. Electron beam irradiation was used to promote synthesis of hybrid structures while using silanol-terminated PDMS, TEOS and TPOZ as precursors. Evaluation of the method’s performance was executed by gel fraction determination, WDXRF and FTIR-ATR. Results showed that, although there is some pre-irradiation reactivity between precursors, radiolysis induces scission on multiple sites of precursor’s structures, which induces hybrid network formation to a greater extent. Characterisation allowed determining electron beam irradiation to be effective in the creation of Si–O–Zr bonds, resulting in the production of a Class II hybrid material.

© 2016 Taylor {&} Francis.A laboratory-based methodology was designed to assess the bioreceptivity of glazed tiles. The experimental set-up consisted of multiple steps: manufacturing of pristine and artificially aged glazed tiles, enrichment of phototrophic microorganisms, inoculation of phototrophs on glazed tiles, incubation under optimal conditions and quantification of biomass. In addition, tile intrinsic properties were assessed to determine which material properties contributed to tile bioreceptivity. Biofilm growth and biomass were appraised by digital image analysis, colorimetry and chlorophyll a analysis. SEM, micro-Raman and micro-particle induced X-ray emission analyses were carried out to investigate the biodeteriorating potential of phototrophic microorganisms on the glazed tiles. This practical and multidisciplinary approach showed that the accelerated colonization conditions allowed different types of tile bioreceptivity to be distinguished and to be related to precise characteristics of the material. Aged tiles showed higher bioreceptivity than pristine tiles due to their higher capillarity and permeability. Moreover, biophysical deterioration caused by chasmoendolithic growth was observed on colonized tile surfaces.