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Meunier, Emmanuelle, Filipa Dias, João Fonte, Alexandre Lima, Alexandra Rodrigues, Carlo Bottaini, Rui JC Silva, João P. Veiga, Manuel F. C. Pereira, and Elin Figueiredo. "Later prehistoric tin mining in the Ervedosa mine (Vinhais, Portugal): evidence and context." 15.4 (2023): 43. AbstractWebsite

This paper presents a comprehensive study of the evidence for ancient tin mining at the Ervedosa mine (Vinhais, Portugal). The geological context of the site indicates a rich cassiterite (SnO2) deposit, which was subject to mining in the twentieth century. Some ancient mining and ore processing stone tools were recovered during the twentieth century mining operations, namely one hammer, one pounder, one flat anvil and five small tools used both as pounders and crushing anvils, evidencing prehistoric mining activities. XRF and SEM–EDS chemical analyses were performed on primary and secondary cassiterite samples from the mining site, demonstrating the abundance and chemical heterogeneity of the tin (Sn) ores. The stone tools can be ascribed to Bronze Age or, at the latest, Early Iron Age (2nd millennium to the first half of 1st millennium BCE) by comparison with similar tools from other Iberian and European archaeological contexts. High-resolution photogrammetric 3D models of the tools are made available in this study. The historical descriptions of the findings and the research made on the technical archives about the mine allowed correlating the tools to mining in a primary context, focused on rich quartz veins in granitic or greisen bedrock, rather than mining in a secondary context. XRF and SEM–EDS analyses performed on the stone material and on surface adherences support their identification as specific types of hard rocks, such as granite, amphibolite and quartzite, and allowed the detection of Sn-rich adherent particles, confirming their use for Sn-material processing. The potential relation between the cassiterite resources and the local later prehistoric (Bronze Age to Early Iron Age) settlement pattern is also discussed. The results raise awareness and provide relevant data about the existence of tin mining in primary contexts during later prehistoric times in the NW Iberian Peninsula.

Rodrigues, Alexandra P., Pedro M. P. Santos, João Pedro Veiga, Maria Helena Casimiro, and Luís M. Ferreira. "Electron Beam Irradiation on the Production of a Si- and Zr-Based Hybrid Material: A Study by FTIR and WDXRF." Materials. 16 (2023). AbstractWebsite

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.

Chaves, Rute Correia, João Pedro Veiga, and António Monge Soares. "Characterization of Chalcolithic Ceramics from the Lisbon Region, Portugal: An Archaeometric Study." Heritage. 5 (2022): 2422-2443. AbstractWebsite

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.

Silva, Teresa P., Daniel de Oliveira, João P. Veiga, Vitor Lisboa, Jorge Carvalho, Alexandra M. Barreiros, Mathilda L. Coutinho, Eduardo Salas-Colera, and Rogério Vigário. "Contribution to the Understanding of the Colour Change in Bluish-Grey Limestones." Heritage. 5 (2022): 1479-1503. AbstractWebsite

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.

Coutinho, Mathilda Larsson, João Pedro Veiga, Andreia Ruivo, Teresa Pena, Eduardo Salas Colera, Augusta Lima, Elin Figueiredo, Marine Cotte, Margarida Lima, and others. "An insight on the firing condition of Chinese blue-and-white porcelain through XANES." Journal of Analytical Atomic Spectrometry (2022). Abstract
Carvalho, Fernanda, Pedro Sousa, Nuno Leal, Joaquim Simão, Elissavet Kavoulaki, Maria Margarida Lima, Teresa Pereira da Silva, Hugo Águas, Giuseppina Padeletti, and João Pedro Veiga. "Mortars from the Palace of Knossos in Crete, Greece: A Multi-Analytical Approach." Minerals. 12 (2022): 30. Abstract
Figueiredo, Elin, Alexandra Rodrigues, João Fonte, Emmanuelle Meunier, Filipa Dias, Alexandre Lima, José Alberto Gonçalves, Luís Gonçalves-Seco, Filipe Gonçalves, Manuel F. C. Pereira, Rui JC Silva, and João P. Veiga. "Tin and Bronze Production at the Outeiro de Baltar Hillfort (NW Iberia)." Minerals. 12 (2022). AbstractWebsite

Findings of Iron Age metallurgical activities related to tin metal and mining are very rare. In the present work, we present a detailed study of the Outeiro de Baltar hillfort, dated to the Late Iron Age/Early Roman period, located in a place where 20th century tin mining work took place. Elemental and microstructural analysis by portable, micro and wavelength dispersive X-ray fluorescence spectrometry (pXRF, micro-XRF and WDXRF) and scanning electron microscopy with energy dispersion spectrometer (SEM-EDS) showed that metallurgical debris found at the archaeological site is related to tin smelting and binary and ternary bronze productions. Analysis of the artefacts of diverse typologies found at the site showed that a variety of metals and alloys were in circulation and use. Samples of tin ores (cassiterite) from the region were analyzed for comparison with an archaeological tin slag from the site. The analytical results point to the production of tin metal using local cassiterite and the production of bronze by directly adding cassiterite into a smelting process. Furthermore, data of remote sensing (airborne Light Detection and Ranging (LiDAR) and historical aerial imagery) and Geographical Information System (GIS) mapping were combined with archival mining documentation and maps to retrieve a landscape context for the site. The study showed that the place of the Outeiro de Baltar hillfort (NW Iberia) was mined periodically over time.

Wrona, Paweł, Zenon Różański, Grzegorz Pach, Adam P. Niewiadomski, and João Pedro Veiga. "Historical Outline of Iron Mining and Production in the Area of Present-Day Poland." Minerals. 11 (2021): 1136. Abstract
del Sanjuán Sánchez, Ursula Pilar, Juan Herrera Herbert, Joao Pedro Veiga, Alicia López Mederos, Maria Muñiz Fernandez, Alicia Calvo Paz, Carlos Carrión Isaacs, Lu{\'ıs Vela Bárez, and Guillermo Pérez de Gracia D{\'ıaz. "MINEHERITAGE: An innovative education project linking European mining history with the modern European society development." (2021). Abstract
Silva, Teresa P., João X. Matos, Daniel de Oliveira, Igor Morais, Pedro Gonçalves, Lu{\'ıs Albardeiro, Fernanda Carvalho, Ugur D. Menda, and João P. Veiga. "Orange Pickeringite from the Algares 30-Level Adit, Aljustrel Mine, Iberian Pyrite Belt, Portugal." Minerals. 11 (2021): 1115. Abstract
Silva, Teresa P., João X. Matos, Daniel de Oliveira, João P. Veiga, Igor Morais, Pedro Gonçalves, and Lu{\'ıs Albardeiro. "Mineral Inventory of the Algares 30-Level Adit, Aljustrel Mine, Iberian Pyrite Belt, Portugal." Minerals. 10 (2020): 853. Abstract
Coutinho, Mathilda L., João Pedro Veiga, Maria Filomena Macedo, and Ana Zélia Miller. "Testing the Feasibility of Titanium Dioxide Sol-Gel Coatings on Portuguese Glazed Tiles to Prevent Biological Colonization." Coatings. 10 (2020): 1169. Abstract
Silva, TP, D. P. S. Oliveira, JP Veiga, P. Ávila, C. Candeias, E. Salas-Colera, and R. Caldeira. "Mineralogy and chemistry of incrustations resulting from the 2014–2015 eruption of Fogo volcano, Cape Verde." Bulletin of Volcanology. 81.4 (2019): 23 (17 pp).
Figueiredo, E., J. Fonte, A. Lima, JP Veiga, R. J. C. Silva, and J. Mirão. "Ancient tin production: Slags from the Iron Age Carvalhelhos hillfort (NW Iberian Peninsula)." Journal of Archaeological Science. 93 (2018): 1-16.
Carvalho, F., A. Lopes, A. T. Curulli, TP Silva, M. M. A. Lima, G. Montesperelli, S. Ronca, G. Padeletti, and JP Veiga. "The Case Study of the Medieval Town Walls of Gubbio in Italy: First Results on the Characterization of Mortars and Binders." Heritage. 1.2 (2018): 468-478.
Monteiro, R. C. C., A. A. S. Lopes, M. M. R. A. Lima, and J. P. B. Veiga. "Thermal characteristics and crystallization behavior of zinc borosilicate glasses containing Nb2O5." Journal of Non-Crystalline Solids. 491 (2018): 124-132.
Kullberg, A. T. G., A. A. S. Lopes, J. P. B. Veiga, and R. C. C. Monteiro. "Crystal growth in zinc borosilicate glasses." Journal of Crystal Growth. 457 (2017): 239-243. AbstractWebsite

Glass samples with a molar composition (64+x)ZnO-(16-x)B2O3-20SiO2, where x=0 or 1, were successfully synthesized using a melt-quenching technique. Based on differential thermal analysis data, the produced glass samples were submitted to controlled heat-treatments at selected temperatures (610, 615 and 620{\{}$\backslash$textdegree{\}}C) during various times ranging from 8 to 30h. The crystallization of willemite (Zn2SiO4) within the glass matrix was confirmed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Under specific heat-treatment conditions, transparent nanocomposite glass-ceramics were obtained, as confirmed by UV-vis spectroscopy. The influence of temperature, holding time and glass composition on crystal growth was investigated. The mean crystallite size was determined by image analysis on SEM micrographs. The results indicated an increase on the crystallite size and density with time and temperature. The change of crystallite size with time for the heat-treatments at 615 and 620{\{}$\backslash$textdegree{\}}C depended on the glass composition. Under fixed heat-treatment conditions, the crystallite density was comparatively higher for the glass composition with higher ZnO content. {\{}©{\}} 2016.

Figueiredo, E., A. Lackinger, B. C. Rey, R. J. C. Silva, JP Veiga, and J. Mirão. "An Experimental Approach for Smelting Tin Ores From Northwestern Iberia." Materials and Manufacturing Processes. 32 (2017): 765-774.
Silva, TP, D. P. S. Oliveira, M. J. Batista, JP Veiga, F. Noronha, and J. X. Matos. "Rhenium ocurrence in Portugal: an overview considering the valorisation of mineral resources." Rhenium, Properties, Uses and Occurrences. Ed. Eric James. New York: Nova Science Publishers Inc. New York, 2017. 85-116.
Lackinger, Aaron, Cristina Fernández Fernández, Beatriz Comendador Rey, Elin Figueiredo, João P. Veiga, and Rui JC Silva. "Sacar el estaño de las piedras: un procedimiento artesanal para la obtención la obtención de estaño en la Galicia Meridional." Presente y futuro de los paisajes mineros del pasado: Estudios sobre miner{\'ıa, metalurgia y poblamiento. Editorial Universidad de Granada, 2017. 259-267. Abstract
Coutinho, M. L., JP Veiga, L. C. Alves, J. Mirão, L. Dias, A. M. Lima, V. S. Muralha, and MF Macedo. "Characterization of the glaze and in-glaze pigments of the nineteenth-century relief tiles from the Pena National Palace, Sintra, Portugal." Applied Physics A: Materials Science and Processing. 122.7 (2016): 1-10. Abstract

© 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.

Kullberg, A. T. G., A. A. S. Lopes, J. P. B. Veiga, M. M. R. A. Lima, and R. C. C. Monteiro. "Formation and crystallization of zinc borosilicate glasses: Influence of the ZnO/B2O3." Journal of Non-Crystalline Solids. 441 (2016): 79-85. Abstract

© 2016 Elsevier B.V. All rights reserved.Different glasses based on the ZnO-B2O3-SiO2 system, with a ZnO content ≥ 60 mol{%} and a fixed SiO2 content (20 mol{%}), were synthesised using a melt-quenching method. Glass samples with zinc oxide concentrations as high as 65 mol{%} were prepared successfully without deteriorating the glass-forming ability. The glass samples were submitted to controlled heat-treatments, and the effect of the ZnO/B2O3 molar ratio on the formation of crystalline phases within the glass matrix was investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DTA results indicated that the glass transition and the onset crystallization temperatures of the studied glasses tended to increase with the increment on the ZnO/B2O3 ratio. XRD data showed that the zinc binary crystalline phases, willemite (Zn2SiO4), a zinc orthosilicate, and zinc borate (Zn3B2O6) could be present in the crystallized glasses, depending on the heat-treatment conditions. The formation of willemite was promoted by an increasing ZnO/B2O3 ratio. Microstructural observations performed by SEM indicated that under controlled experimental parameters (glass composition, heat-treatment temperature and time) the precipitation of nanocrystals within the glass matrix can be achieved, resulting in transparent and translucent willemite glass-ceramics.

Coutinho, M. L., A. Z. Miller, M. A. Rogerio-Candelera, J. Mirão, L. Cerqueira Alves, JP Veiga, H. Águas, S. Pereira, A. Lyubchyk, and MF Macedo. "An integrated approach for assessing the bioreceptivity of glazed tiles to phototrophic microorganisms." Biofouling. 32.3 (2016): 243-259. Abstract

© 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.

Figueiredo, Elin, Beatriz Comendador Rey, João Fonte, Emmanuelle Meunier, Aaron Lackinger, Rui JC Silva, João Pedro Veiga, Carlo Bottaini, José Mirão, and Alexandre Lima. "Estanho antigo no Noroeste Peninsular: uma abordagem multidisciplinar e transfronteiriça para o estabelecimento de uma visão integrada." XI Congresso Ibérico de Arqueometria. 2015. Abstract
Silva, Teresa Pereira, João Pedro Veiga, Daniel PS Oliveira, Maria João Batista, Diogo Rosa, and Ondina M. Figueiredo. "A utilização da radiação de sincrotrão no estudo de materiais geológicos; breve abordagem sobre experiências recentes de um grupo de utilizadores." Geonovas (2015). Abstract