Porta S.N. & Matthaes P., 2015-Non destructive analyses applied to archaeological potteries and bronzes. Atti Acc. Rov. Agiati, a. 265, 2015, ser. IX, vol. V, B: 117-130. An archaeological object is fi rst of all a combination of... more
Porta S.N. & Matthaes P., 2015-Non destructive analyses applied to archaeological potteries and bronzes. Atti Acc. Rov. Agiati, a. 265, 2015, ser. IX, vol. V, B: 117-130. An archaeological object is fi rst of all a combination of information concerning the geological aspects of its origin context. Th e interaction between the archeological artifacts and their environment leads to the formation of mineral encrustations and corrosions that could be considered as authenticity markers. Diff erent types of superfi cial alterations have been analysed by FT-IR and UVF, in order to develope an analytical procedure for studying from scratch objects within private and museum collections.
Painter Alfredo Volpi (1896-1988) was one of the most important Brazilian artists of recent years. His extensive work was characterized mainly by chromatic compositions and geometric abstractions. He attributed great importance to craft... more
Painter Alfredo Volpi (1896-1988) was one of the most important Brazilian artists of recent years. His extensive work was characterized mainly by chromatic compositions and geometric abstractions. He attributed great importance to craft and materials, developing his own systematic way of working, making his own canvas, paint, and pigments with naturally occurring earth pigments. The current study, making use of complementary non-destructive analytical techniques, sought to study the chromatic and elemental composition characteristics of his paintings while gathering information on the technical procedures the artist may have used, in the belief that these are key elements for a deeper understanding of his work. Two tempera paintings on canvas were analyzed, both finished around 1950-1960, a period when the artist’s work underwent a major transformation, from figurativism to abstraction, from the use of industrial oil-based paints to the medieval technique of tempera. Techniques of visual examination based on ultraviolet, visible, and infrared photography were used to gather information about the artist’s creative process. These techniques also helped to detect past interventions and to identify pigments. A spectrophotometer was used to measure the color based on the reflectance spectrum and numerical reference coordinates within a uniform color space while X-ray fluorescence was used for elemental characterization of the materials. The integration of these techniques made it possible to identify a part of the rich palette of Volpi’s paintings and to document the present aspects of the colors and the current condition of the works under study. We were also able to recognize or give indications of pigment and ground compositions and to shed light on parts of each of the works’ backgrounds, such as the presence of sketches, covered earlier paintings and brushstrokes. The techniques used have proven useful in characterizing the paintings, revealing new information about the artist’s work. The resulting information may be the beginning of a database of his oeuvre.
Painter Alfredo Volpi (1896-1988) was one of the most important Brazilian artists of recent years. His extensive work was characterized mainly by chromatic compositions and geometric abstractions. He attributed great importance to craft... more
Painter Alfredo Volpi (1896-1988) was one of the most important Brazilian artists of recent years. His extensive work was characterized mainly by chromatic compositions and geometric abstractions. He attributed great importance to craft and materials, developing his own systematic way of working, making his own canvas, paint, and pigments with naturally occurring earth pigments. The current study, making use of complementary non-destructive analytical techniques, sought to study the chromatic and elemental composition characteristics of his paintings while gathering information on the technical procedures the artist may have used, in the belief that these are key elements for a deeper understanding of his work. Two tempera paintings on canvas were analyzed, both finished around 1950-1960, a period when the artist’s work underwent a major transformation, from figurativism to abstraction, from the use of industrial oil-based paints to the medieval technique of tempera. Techniques of visual examination based on ultraviolet, visible, and infrared photography were used to gather information about the artist’s creative process. These techniques also helped to detect past interventions and to identify pigments. A spectrophotometer was used to measure the color based on the reflectance spectrum and numerical reference coordinates within a uniform color space while X-ray fluorescence was used for elemental characterization of the materials. The integration of these techniques made it possible to identify a part of the rich palette of Volpi’s paintings and to document the present aspects of the colors and the current condition of the works under study. We were also able to recognize or give indications of pigment and ground compositions and to shed light on parts of each of the works’ backgrounds, such as the presence of sketches, covered earlier paintings and brushstrokes. The techniques used have proven useful in characterizing the paintings, revealing new information about the artist’s work. The resulting information may be the beginning of a database of his oeuvre.
Non-invasive documentation of historic façades with fluorescence lidar techniques can provide helpful information for the cultural heritage sector, especially when large areas outdoors are to be examined. This paper presents a case study... more
Non-invasive documentation of historic façades with fluorescence lidar techniques can provide helpful information for the cultural heritage sector, especially when large areas outdoors are to be examined. This paper presents a case study of the Coliseum, Rome, where both cleaned and heavily soiled areas of the monument were scanned and analysed with two fluorescence lidar systems. Biodeterioration processes were also addressed during the experiment, with the aim of assessing the colonisation extent on selected areas of the ...
The families of monocotyledons can be divided into two groups on the basis of the presence (Group A) or absence (Group B) of ester-linked ferulic acid in their unlignified cell walls (UCW). In the Poaceae this ferulic acid is linked to... more
The families of monocotyledons can be divided into two groups on the basis of the presence (Group A) or absence (Group B) of ester-linked ferulic acid in their unlignified cell walls (UCW). In the Poaceae this ferulic acid is linked to glucuronoarabinoxylans, which are major components of these cell walls (CW). The hypothesis was examined that the UCW of the other Group A families also contain glucuronoarabinoxylans as their major noncellulosic polysaccharides, whereas pectic polysaccharides are the major noncellulosic polysaccharides in the UCW of the Group B families. Monosaccharide compositions were determined of UCW from one species in each of nine Group A families, eight Group B families, and, for comparison, two families of dicotyledons. The results mostly supported the hypothesis. The UCW of Group A monocotyledons contained large proportions of arabinose and xylose and greater proportions of glucuronic acid than the CW of Group B. This is consistent with the presence of large proportions of glucuronoarabinoxylans in these CW. In contrast, the UCW of Group B monocotyledons had monosaccharide compositions similar to those of the dicotyledons. They contained large proportions of galactose and galacturonic acid, consistent with the presence of large proportions of pectic polysaccharides. Two Group B species [Egeria densa (Hydrocharitaceae) and Potamogeton crispus (Potamogetonaceae)] were unusual in having CW containing large proportions of xylose. One Group A species, Phoenix reclinata (Arecaceae) was exceptional in having CW with a monosaccharide composition similar to dicotyledons. The results are discussed in relation to cladograms constructed from DNA nucleotide sequences from the chloroplast gene rbcL and a possible sequence is proposed for the evolution of the composition of UCW of monocotyledons.
UV-fluorescence microscopy provides a powerful tool for the assessment of the coherence of pollen and organic-walled microfossil assemblages in situations where recycling or the intrusion of younger pollen is suspected. It also provides... more
UV-fluorescence microscopy provides a powerful tool for the assessment of the coherence of pollen and organic-walled microfossil assemblages in situations where recycling or the intrusion of younger pollen is suspected. It also provides sensitive information about the thermal maturity of pollen, important for assessing whether material has been heated. Examples are given from the Palaeolithic sites at Barnham, Suffolk, UK;
Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the... more
Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time.
