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Mendes M.T.,University of Evora | Mendes M.T.,National Laboratory for Civil Engineering | Pereira S.,National Laboratory for Civil Engineering | Ferreira T.,University of Evora | And 3 more authors.
International Journal of Conservation Science

In order to aid research, improve preservation actions and develop better options for future interventions it is important to know the preservation materials and procedures adopted throughout the past and especially the ones being adopted nowadays. A survey to specialists working in situ in preservation and restoration of glazed decorative tiles has been performed aiming at getting insight on their type of training, work portfolio, opinions, the current materials and procedures used in the diverse phases of a preservation intervention (diagnosis, cleaning, consolidation, bonding fragments and fixing of glazed layer, volumetric and chromatic reintegration, final coating, resetting of tiles and manufacture of replicas) and the criteria/factors that support the specialists choices. Source

Relvas C.,University of Evora | Nunes M.,University of Evora | Santos M.,University of Evora | Mourinha P.,University of Evora | And 3 more authors.
Science, Technology and Cultural Heritage - Proceedings of the 2nd International Congress on Science and Technology for the Conservation of Cultural Heritage, 2014

Three paper samples made of rag fibres, rag and bleached softwood fibres, and mechanical pulp, presenting foxing stains, were studied by non-destructive techniques. Fibre disruption was observed on fox spots on one of the samples, while accumulation of calcite particles occurred on another sample. The third sample presented no morphological alteration of the surface on the foxing stains. The two wood pulp papers contained kaolinite as filler and muscovite was also detected, probably due to contamination of kaolinite. Calcium sulphate is also present in one of these samples. Calcite was detected in the rag paper. Either resinaceous or proteinaceous materials were used as sizing agents. EDXRF analysis showed no differences, within the standard deviation, for the iron and copper contents in the foxed and unfoxed areas. ATR-FT-IR has shown to be an adequate technique to detect biotic attack on the stains. Five bacterial strains were isolated either from the foxed and unfoxed areas and one fungal strain belonging to the Penicillium genera was isolated from the foxed areas. © 2014 Taylor & Francis Group, London. Source

Ferreira T.,University of Evora | Moreiras H.,University of Evora | Manhita A.,University of Evora | Tomaz P.,Laboratorio Jose Of Figueiredo | And 3 more authors.
Microscopy and Microanalysis

A 16th century liturgical cope belonging to D. Teotónio of Braganza (collection of the Museum of Évora, ME 172/1) was selected for a material study. The cope is made of a variety of materials that include two different types of metal threads, dyed silk yarns, and vegetable yarns used in the weft. Several samples from different points representing the different metal thread types and colored silk yarns were collected. Stereomicroscopy (optical microscopy) and scanning electron microscopy were used for morphological analysis of the textile fibers and evaluation of metal thread degradation products. Evaluation of mordants and metal thread composition was carried out by energy-dispersive X-ray spectroscopy. Liquid chromatography with diode array and mass spectrometry detection was used for dye identification, which allowed the determination of three different red dye sources and one yellow dye source in the colored silk yarns. Although different fabrics were used in the manufacturing of the cope, similarities identified in the characterization of the materials suggest that a single workshop was involved in its making. © © Microscopy Society of America 2014. Source

Mendes M.T.,National Laboratory for Civil Engineering | Mendes M.T.,University of Evora | Esteves L.,Museu Nacional do Azulejo | Ferreira T.A.,University of Evora | And 5 more authors.
Applied Physics A: Materials Science and Processing

Knowledge of current conservation materials and methods together with those adopted in the past is essential to aid research and improve or develop better conservation options. The infill and painting of tile lacunae are subjected to special requirements mainly when used in outdoor settings. A selection of the most commonly used materials was undertaken and performed based on inquiries to practitioners working in the field. The infill pastes comprised organic (epoxy, polyester), inorganic (slaked lime, hydraulic lime and zinc hydroxychloride) and mixed organic–inorganic (slaked lime mixed with a vinylic resin) binders. The selected aggregates were those most commonly used or those already present in the commercially formulated products. The infill pastes were characterised by SEM, MIP, open porosity, water absorption by capillarity, water vapour permeability, thermal and hydric expansibilities and adhesion to the ceramic body. Their performance was assessed after curing, artificial ageing (salt ageing and UV–Temp–RH cycles) and natural ageing. The results were interpreted in terms of their significance as indicators of effectiveness, compatibility and durability. © 2016, Springer-Verlag Berlin Heidelberg. Source

Pereira F.,New University of Lisbon | Pereira F.,University of Lisbon | Silva R.J.C.,New University of Lisbon | Monge Soares A.M.,University of Lisbon | And 5 more authors.
Microscopy and Microanalysis

Archaeological materials present unique records on natural processes allowing the study of long-term material behaviors such as structural modifications and degradation mechanisms. The present work is focused on the chemical and microstructural characterization of four prehistoric arsenical copper artifacts. These artifacts were characterized by micro-energy dispersive X-ray fluorescence spectrometry, optical microscopy, scanning electron microscopy with X-ray microanalysis, micro-X-ray diffraction and synchrotron radiation micro-X-ray diffraction. Cu3As is the expected intermetallic arsenide in arsenical copper alloys, reported in the literature as exhibiting a hexagonal crystallographic structure. However, a cubic Cu3As phase was identified by X-ray diffraction in all of our analyzed archaeological artifacts, while the hexagonal Cu3As phase was clearly identified only in the artifact with higher arsenic content. Occurrence of the cubic arsenide in these particular objects, suggests that it was precipitated due to long-term aging at room temperature, which points to the need of a redefinition of the Cu-As equilibrium phase constitution. These results highlight the importance of understanding the impact of structural aging for the assessment of original properties of archaeological arsenical copper artifacts, such as hardness or color. © Microscopy Society of America 2015 Source

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