http://hdl.handle.net/10362/4399 Tue, 21 May 2013 08:57:27 GMT 2013-05-21T08:57:27Z http://hdl.handle.net/10362/5145 Title: Energy-dispersive x-ray fluorescence analysis of modern coloured glasses from Marinha Grande (Portugal) Authors: Matos, Antonio Pires de; Valério, P; Markowicz, A; Kregsamer, P; Araújo, M F; Chinea-Cano, E; Carvalho, C Abstract: The elemental composition (K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Ba, Nd and Pb) of modern coloured glasses was obtained by energy-dispersive x-ray fluorescence (EDXRF) spectrometry. This nondestructive technique is frequently used in the analysis of historical glass objects. Two reference glasses were also measured to assess the overall accuracy of the EDXRF method. Reference and unknown glasses were analysed without any preparation. The coloured glass samples studied belong to the Glass Museum of Marinha Grande and were chosen from two distinct collections, which were characterized by the different concentrations of some elements (K, Ti, Cr, Mn, Fe, Ba and Pb). The determined major elements allowed the identification of two raw materials used in glass manufacture, sand and lime. Multivariate statistical analysis, namely principal component extraction, simplified the identification of some of the colouring chemical elements, associating them with the different colours of the glass objects. Description: X-Ray Spectrom. 2003; 32: 396–401 Tue, 01 Jul 2003 00:00:00 GMT http://hdl.handle.net/10362/5145 2003-07-01T00:00:00Z http://hdl.handle.net/10362/4522 Title: Anatase as an alternative application for preventing biodeterioration of mortars: evaluation and comparison with other biocides Authors: Macedo, Maria Filomena; Fonseca, Ana Josina; Pina, Fernando; Leal, Nuno Abstract: The aim of this study is the comparison between different treatments(anatase and two conventional biocides:Biotin T and Anios)for preventing biodeterioration of mortars.The treatments were applied both in the laboratory on mortar slabs and in situ on walls of Palácio Nacional da Pena(Sintra,Portugal). Mortar slabs treated with anatase (pure and Fe3þ doped)applied as acoating or by mixing within the mortar were prepared,and their surfaces characterized by different methodologies.The mortars were inoculated with cyanobacteria and chlorophyta species,incubated for a period of 4 months and the chlorophyll content quantified by extraction method and fluorescence emission.For comparison purposes untreated mortar slabs were inoculated,incubated and finally treated with the biocides.After two weeks the respective chlorophyll contents was quantified. In situ studies in two external walls of Palácio Nacional da Pena covered by organisms were also performed by direct application of aqueous solutions of the three products,and the efficiency of the treatment monitored by spectrophotometry using the CIELAB method.Lichens and other phototrophic microorganisms were identified by direct observation with a microscope and cyanobacteria,green microalgae, bacteria and fungi by DNA-based molecular analysis targeting the 16S and 18S ribosomal RNAgenes. The results show that anatase is a better agent for preventing biodeterioration than the two tested conventional biocides,both in mortars slabsand in situ studies.In fact,photographic and colorimetric records made in two external walls of Palácio Nacional da Pena after two weeks of treatments application showed that lichens and other phototrophic microorganisms disappear from the places where anatase was applied. Description: International Biodeterioration & Biodegradation 64(2010)388 e 396 Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10362/4522 2010-01-01T00:00:00Z http://hdl.handle.net/10362/4475 Title: Mapping and characterization of a green biofilm inside of Vilar de Frades Church (Portugal) Authors: Macedo, Maria Filomena; Miller, Ana Zélia Abstract: Vilar de Frades church is integrated in the Vilar de Frades Monastery, located in the North part of Portugal (Barcelos). The monastery, founded in 566, suffered several architectural modifications and restoration works, the most relevant was in the XVI century. The church, in granite, has one nave and six bays,holding ten chapels with vaults of crossed ribbings. Nowadays, the chapels present a severe biological colonization characterised by an intense green biofilm, which becoming apparent in other locations inside the church. In the course of a general survey concerning the conservation state of the church, an accurate campaign was planned in order to assess the main biodeterioration agents, map biological colonization and determine the environmental conditions. Laboratory analyses were accomplished with optical microscopy and spectrofluorometry. This study presents the results of this campaign. Details on conservation or preservation works that need to be implemented are also presented. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/10362/4475 2006-01-01T00:00:00Z http://hdl.handle.net/10362/4474 Title: The influence of inherent properties of building limestones on their bioreceptivity to phototrophic microorganisms Authors: Macedo, Maria Filomena; Miller, Ana Zélia; Dionísio, Amélia; Laiz, Leonila; Saiz-Jimenez, Cesareo Abstract: The influence of open porosity, water absorption capillarity, water vapour permeability, surface roughness, stone pH and chemical composition on stone bioreceptivity to phototrophic microorganisms was assessed by means of a thorough stone characterisation with subsequent artificially inoculation of limestone samples with a multi-species phototrophic culture and placing them inside a growth chamber for 90 days. A principal component analysis and an analysis of variance(ANOVA) were carried out in order to evaluate the direct relationships between stone bioreceptivity and petrophysical properties. From the principal component analysis, two main components were obtained and assigned a petrophysical/photosynthetic biomass meaning. Stone bioreceptivity, quantified by the amount of chlorophyll a and intensity of chlorophyll a fluorescence present on the stone samples after 90 days-incubation, was included in both principal components. The first component was linked to the amount of chlorophyll a and was highly and linearly associated to capillarity and roughness,and less associated with open porosity and water vapour permeability. The second component, linked to the intensity of chlorophyll a fluorescence measured on the stone surfaces, was not linearly associated with the petrophysycal properties,showing the fallibility of this in vivo chlorophyll quantification technique on the estimation of photosynthetic biomass growing on stone materials, particularly when endolithic growth occurs. Description: Annals of Microbiology, 59 (4) 705-713 (2009) Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/10362/4474 2009-01-01T00:00:00Z