Browsing by Author "Moreira, Patrícia Raquel"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Art casting in Portuguese 19th century industrial foundries: a multi-analytical study of an emblematic copper-based alloy monumentPublication . General-Toro, Pablo; Bordalo, Rui; Moreira, Patrícia Raquel; Vieira, Eduarda; Brunetti, Antonio; Iannaccone, Roberta; Bottaini, CarloThe outdoor sculpture of the first Portuguese king, D. Afonso Henriques (~1109 – 1185 AD), placed in Guimarães (North Portugal) is one of the most emblematic national sculptures. Created in 1887 by António Soares dos Reis, it possesses a remarkable symbolic value in the presumed birthplace of the king. In addition to the artistic and heritage importance of the monument, it is one of the few sculptures cast by a Portuguese industrial foundry in the 19th-century. This study obtained data on the sculpture's elemental composition and corrosion products, gathering important historical and technical information. For this purpose, a multi-analytical approach consisting of X-ray fluorescence (XRF), X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM-EDS) was carried out to characterise the bulk metal and corrosion layers. The data revealed a ternary alloy of Cu, Sn, Zn with Pb, Fe, As, Bi and Mn as minor elements. The alloy matches that of other sculptures cast in that period. In terms of corrosion, it is characterised by the presence of oxides. These results represent the first step for applying an appropriate conservation strategy for bronze sculptures with similar characteristics.
- Art casting in portuguese 19th century industrial foundries: a multi-analytical study of an emblematic copper-based alloy monumentPublication . General-Toro, Pablo; Bordalo, Rui; Moreira, Patrícia Raquel; Vieira, Eduarda; Brunetti, Antonio; Iannaccone, Roberta; Bottaini, CarloThe outdoor sculpture of the first Portuguese king, D. Afonso Henriques (c. 1109–1185 AD), placed in Guimarães (North Portugal), is one of the most emblematic national sculptures. Created in 1887 by António Soares dos Reis, it possesses a remarkable symbolic value in the presumed birthplace of the king. In addition to the artistic and heritage importance of the monument, it is one of the few sculptures cast by a Portuguese industrial foundry in the 19th century. This study obtained data on the sculpture’s elemental composition and corrosion products, gathering important historical and technical information. For this purpose, a multi-analytical approach consisting of X-ray fluorescence (XRF), X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM-EDS) was carried out to characterise the bulk metal and corrosion layers. The data revealed a ternary alloy of Cu, Sn and Zn, with Pb, Fe, As, Bi and Mn as minor elements. The alloy matches that of other sculptures cast in that period. In terms of corrosion, it is characterised by the presence of oxides. These results represent the first step for applying an appropriate conservation strategy for bronze sculptures with similar characteristics.
- BIONANOSCULP: development of chitosan-based coatings as an eco-friendly strategy for conservation of outdoor sculpturesPublication . Silva, Nádia; Castro, Diana; Vieira, Eduarda; Pintado, Manuela; Moreira, Patrícia RaquelUrban outdoor sculptures, which are an immeasurable part of our cultural heritage, are easily vulnerable to chemical and physical alterations due to their exposure to weather elements and air pollution. These alterations are aggravated by the colonization of degrading microorganisms. Nowadays, the products used for biodeterioration control of such cultural objects lack versatility or are toxic to the environment and the human health. In order to find new alternatives based on non-toxic and sustainable materials, the BIONANOSCULP project proposes the development of an antimicrobial protective layer for the preventive conservation of outdoor sculptures. For that, chitosan has been tested as a base biopolymer for the synthesis of protective coatings due to its proven antimicrobial properties. Different concentrations and molecular weights of chitosan, as well as the addition of adjuvants and cross-linking agents were tested to obtain coatings with relevant properties for application on metal and stone sculptures. Antimicrobial activity testing, together with physical and chemical assessments are being performed to characterize and evaluate the suitability of the coatings as protective layers able to slow down the growth of relevant microorganisms. Permeability assays and compatibility of the coatings to stone and metal samples are also being considered in order to analyze their performance on different materials while not causing alterations to the original aesthetics of the sculptures.
- Lignin transformation by a versatile peroxidase from a novel bjerkandera sp. strainPublication . Moreira, Patrícia Raquel; Almeida-Vara, Elsa; Malcata, F. Xavier; Duarte, José CardosoA versatile peroxidase, purified from a novel strain of Bjerkandera sp. (B33/3), was tested for its reactivity on a lignin fraction obtained from straw pulping. The effects of such processing parameters as reaction time, pH, and lignin:enzyme ratio were evaluated. Gel filtration chromatography was employed to characterise the molecular mass distribution of the lignin fragments produced by the enzyme-mediated reaction. Our results have shown that such a versatile peroxidase can directly bring about transformations of lignin, even in the absence of external mediators.
- Molecular characterisation of a peroxidase from a Bjerkandera sp.Publication . Moreira, Patrícia Raquel; Duez, Colette; Dehareng, Dominique; Antunes, Adélio; Almeida-Vara, Elsa; Frère, Jean Marie; Malcata, F. Xavier; Duarte, José Cardoso