Thiago Sevilhano Puglieri | University of California, Los Angeles (original) (raw)
Papers by Thiago Sevilhano Puglieri
Neste trabalho - que tem foco na contextualização da química e no impacto que essa atividade pode... more Neste trabalho - que tem foco na contextualização da química e no impacto que essa atividade pode ter na preservação patrimonial e na alfabetização científica - propôs-se, elaborou-se, aplicou-se e avaliou-se uma atividade que objetivou promover o ensino de química por meio do patrimônio cultural ao mesmo tempo em que suscitou a preservação patrimonial e a alfabetização científica na área da química aplicada a bens culturais. O trabalho, desenvolvido por equipe interdisciplinar, fundamentou-se na integração de metodologias de ensino em ciências e de educação para o patrimônio, contemplando o conceitual químico e as implicações sociais e culturais envolvidas no patrimônio. Como resultados, os alunos assimilaram conteúdos de química e demonstraram a apropriação da relação entre ciência e patrimônio. Passaram também a melhor reconhecer o valor e o significado de patrimônio cultural, identificando-se como agentes de preservação e demonstrando o reconhecimento de suas responsabilidades s...
Química Nova, 2016
Paulo (Biblioteca do Conjunto das Químicas), several items were discarded, including apparently m... more Paulo (Biblioteca do Conjunto das Químicas), several items were discarded, including apparently modern worthless large-scale reproductions of paintings by famous painters. A member of staff retrieved these reproductions from the litter bin, one of which was carefully inspected and non-destructively analyzed by spectroscopic techniques (Raman and XRF). The results showed that instead of being a modern reproduction of the gouache "Clinique de Sannois" (Maurice Utrillo, 1923), it was hand-painted probably between the late 1940s and early 1950s using the Jacomet process. This technique was developed by the French printer Daniel Jacomet in the 1920s, who made authorized reproductions of works of art by some of the most celebrated painters of the time.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016
A whitish crystalline-like coating was observed on the surface of the painting "Incêndio", 1990, ... more A whitish crystalline-like coating was observed on the surface of the painting "Incêndio", 1990, produced by Emmanuel Nassar and awarded at the 6th Biennial of Cuenca. This work belongs to the Contemporary Art Museum of the University of São Paulo (MAC-USP) and such coating modified the artwork characteristics, causing an unpleasant effect and compromising its exhibition. The choice of the proper conservation and restoration strategies involves the understanding of the degradation process, demanding the identification of the chemical compounds formed on the painting surface, as well as of the other components in the painting. The results here obtained from Raman and optical microscopies, FTIR-ATR, SEM-EDS and GC-MS, revealed that the efflorescence chemical composition is almost only palmitic acid, with minor contents of stearic acid and their methyl esters, and that the paints are composed by chrome yellow, amorphous carbon and toluidine red pigment; an aluminum silicate filler in the black paint applied on the aluminum ground was also detected. Hierarchical Cluster Analyses (HCA) of the Raman spectra also revealed that the concentration of the efflorescence minor components depends on the paint composition. It was suggested, therefore, that the degradation process resulted from segregation and migration of mainly palmitic acid from the dried paints. Restoration methodologies used in similar cases, as well as factors that contribute to this process, were discussed.
Vibrational Spectroscopy, 2014
In this work the effect of relative humidity (RH) and formaldehyde (H 2 CO) concentration on Pb c... more In this work the effect of relative humidity (RH) and formaldehyde (H 2 CO) concentration on Pb corrosion was investigated; a possible synergism between the aldehyde and CO 2 effects was also considered. Triphasic aqueous salt solutions were used to produce 54% and 75% RH that, together with the 100% RH condition, were combined with 0, 0.62, 55 and 2.0 10 2 mg m −3 formaldehyde concentrations to compose the wanted environments. The results pointed to the conclusion that even at low RH (54%) formates are produced at the metal surface as a consequence of formaldehyde adsorption, indicating that the aldehyde has an active role in Pb corrosion; formates were also observed at relatively low H 2 CO concentration (0.62 mg m −3). No synergism between formaldehyde and carbon dioxide were observed as demonstrated by the Raman images from a corroded Pb coupon, showing that formate and carbonate contributions to the corrosion products were not spatially related. When compared to other volatile organic compounds (VOCs), formaldehyde harmful effect towards metals is frequently underestimated and the results here reported clearly indicate that, even at low RH, its concentration in indoor environments, where it tends to be produced and accumulated, has to be carefully controlled.
Química Nova, 2011
AN EXAMPLE OF RAMAN MICROSCOPY APPLICATION IN THE AUTHENTICATION OF ARTWORKS. In the present work... more AN EXAMPLE OF RAMAN MICROSCOPY APPLICATION IN THE AUTHENTICATION OF ARTWORKS. In the present work, Raman Microscopy was employed in the characterization of the pigments used in a drawing assigned to Tarsila do Amaral, one of the most important Brazilian artists. The work (colored pencil on paper), supposedly produced in the 1920 decade, is of a very simple composition, where blue, green and brown were the colors used. Prussian Blue was found as the blue pigment, whereas green was a mixture of copper phthalocyanine and a yellow dye, probably a diarylide; the brown pigment was a carbonaceous compound. Prussian Blue was replaced by phthalocyanine as pigment since the end of the 1930's and the possibility that it could have been used as pigment in the 1920's can be ruled out.
Heritage
The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest ... more The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest concentration of Indigenous people globally. It represents one of the most extraordinary levels of human, cultural, and artistic diversity, but its material culture is one of the least well-studied. This is especially true in technical art history and conservation science, largely due to (1) the limited international awareness of the richness of materials and techniques used by these Indigenous people and (2) the limitations of knowledge access for many scientists to literature usually published in Portuguese within social sciences and humanities. One result is that these arts are marginalized within technical art history, conservation, and conservation science. To address this knowledge gap, the authors explore 70 materials—among them pigments, dyes, binding media, and varnishes—used for paint production and coloring processes, including syntheses. The authors facilitate research possib...
Heritage, 2023
The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest ... more The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest concentration of Indigenous people globally. It represents one of the most extraordinary levels of human, cultural, and artistic diversity, but its material culture is one of the least well-studied. This is especially true in technical art history and conservation science, largely due to (1) the limited international awareness of the richness of materials and techniques used by these Indigenous people and (2) the limitations of knowledge access for many scientists to literature usually published in Portuguese within social sciences and humanities. One result is that these arts are marginalized within technical art history, conservation, and conservation science. To address this knowledge gap, the authors explore 70 materials—among them pigments, dyes, binding media, and varnishes—used for paint production and coloring processes, including syntheses. The authors facilitate research possibilities within technical art history, conservation, and conservation science by presenting data from historical texts from the 18th and 19th centuries and more recent scientific literature. The work aims to build a more global, inclusive, and decentralized vision of art history and to create a more pluralistic narrative of Indigenous art history from South America.
Vibrational Spectroscopy, 2014
Abstract Vibrational spectroscopy and GC–MS were used to investigate the effect of MnO 2 and α-Fe... more Abstract Vibrational spectroscopy and GC–MS were used to investigate the effect of MnO 2 and α-Fe 2 O 3 on the degradation of methyl linoleate and vegetal and animal fatty. The metal oxides are among the most employed pigments in rock art paintings, whereas the organic compounds were used to mimic organic binders potentially used in such paintings. Both oxides were very effective in the catalytic oxidation of the organic substrates and light had no significant effect, qualitatively or quantitatively, on the final products. In the case of methyl linoleate without metal oxide, the effect of light (visible) was investigated and it was demonstrated that the samples kept in the dark produced relatively less oxidation products, although the main products were the same (hexanal, methyl 9-oxononanoate and methyl octanoate). In the presence of MnO 2 and α-Fe 2 O 3 methyl 9-oxononanoate was the main product, followed by hexanal. The spectral patterns of the oxidation products were different for manganese and iron oxide and GC–MS demonstrated that more compounds are formed in the former than with α-Fe 2 O 3 . Vegetal and animal fatty presented the same behavior that methyl linoleate did. The results here reported indicated that the two pigments considered actively contribute to fat degradation and the presence of inorganic pigments is the main factor to take into account when organic binders degradation in rock art paintings are investigated.
Química Nova, 2019
The preservation of Cultural Heritage is undoubtedly important for the society, and Conservation ... more The preservation of Cultural Heritage is undoubtedly important for the society, and Conservation Science must dedicate itself to attempts to minimize the inherent processes of degradation to which cultural assets are susceptible. In this context, the evaluation of the chemical aspects of the composition of the objects and their relation with the environment where they are located are essential for the understanding of the decay signs observed, supporting the establishment of effective conservation strategies. These characteristics are demonstrated here by vibrational spectroscopy, scanning electron microscopy and microbiological analysis of efflorescences observed in two types of paintings: a tempera on canvas painting ("Barco com bandeirinhas e pássaros", Alfredo Volpi, 1955) and an oil mural painting of the Throne Room of the National Palace of Mafra (18th-19th century, Mafra, Portugal). The challenges involved in the investigation of the efflorescences are demonstrated in both cases, suggesting the occurrence of degradation processes of different origins: in Alfredo Volpi's tempera on canvas painting, the migration of substances from the preparation layer to the surface of the pictorial layer and microbiological colonization; and in the mural painting the migration of calcium salts from the constituent materials of plaster and of neoformation, besides associated microbiological colonization.
Journal of the Brazilian Chemical Society, 2013
Esculturas policromadas de Pb do Museu do Oratório em Ouro Preto (Minas Gerais, Brasil), expostas... more Esculturas policromadas de Pb do Museu do Oratório em Ouro Preto (Minas Gerais, Brasil), expostas em um mostruário de vidro foram severamente degradadas. Os produtos de corrosão foram analisados por difratometria de raios X (XRD), espectroscopia no infravermelho com transformada de Fourier (FTIR), microscopia eletrônica de varredura (SEM), fluorescência de raios X por dispersão de energia (EDX) e microscopia Raman, e constatou-se a formação majoritária de carbonatos e formiatos de Pb. Embora carbonatos sejam comuns na corrosão atmosférica de Pb, formiatos podem ser formados tanto pela ação de ácido fórmico quanto de formaldeído, sendo sua origem um ponto importante a ser investigado. Simulações ambientais com tiras de Pb expostas a possíveis fontes desses compostos orgânicos voláteis possibilitaram concluir que o processo de degradação foi causado principalmente pelo processo de cura da tinta utilizada na base do mostruário. Contudo, produtos de limpeza, que podem conter formaldeído como conservante, mostraram-se potencialmente capazes de causar danos a objetos de chumbo, acelerando sua corrosão. Polychrome lead sculptures from Oratory Museum in Ouro Preto (Minas Gerais, Brazil) kept inside a glass showcase were severely degraded. The formed corrosion products were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) and Raman microscopy and proved to be mostly Pb carbonates and formates. Although carbonate is a very common finding in Pb atmospheric corrosion, Pb formates can be formed by the action of formic acid or formaldehyde, being their origin a key point to be investigated. Environmental simulations with Pb coupons exposed to possible sources of these volatile organic compounds led to the conclusion that the degradation process was caused mainly by the curing process of the painted showcase baseplate. However, cleaning products, which can also contain formaldehyde as preservative, proved to be potentially harmful to Pb, accelerating its corrosion.
Journal of Raman Spectroscopy, 2021
Cadernos do LEPAARQ (UFPEL)
Nesta curta introdução apresenta-se uma breve contextualização da Arqueometria e um breve relato ... more Nesta curta introdução apresenta-se uma breve contextualização da Arqueometria e um breve relato da realização, atividades e trabalhos apresentados no V Congresso Latino-Americano de Arqueometria (V CLA). Mostra-se quantitativamente as origens dos diferentes trabalhos apresentados (no contexto de seus países), suas áreas de concentração dentro da Arqueometria e as técnicas analíticas empregadas. Comenta-se brevemente, ao final, os trabalhos publicados neste dossiê temático, dentro da presente edição da revista Cadernos do LEPAARQ.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 31, 2018
The physicochemical investigation of ceramics crafted and managed by ancient humans allows a bett... more The physicochemical investigation of ceramics crafted and managed by ancient humans allows a better understanding of their social, technological, economical, routine and artistic activities. The Brazilian State of Rio Grande do Sul presents the biggest number of registered archaeological sites in the country, and many of them are earthen mounds, locally known as cerritos de indios. This kind of archaeological site is of utmost importance to understand the social development of the biome Pampa - including areas from Brazil, Argentina and Uruguay - and almost nothing is known about the physicochemical composition of the artifacts from the Brazilian portion. In this work we investigated the mineral phases present in archaeological ceramics from the cerrito Pavão I (PSG-20) by means of white light microscopy (petrography), Raman micro-spectroscopy, XRD and XRF spectroscopies, and FTIR-ATR. Different minerals were identified and allowed to propose a firing temperature of ca. 500-650 °C. ...
Revista CPC
Bens culturais materiais, sejam eles móveis ou imóveis, são constituídos por matéria, que é passí... more Bens culturais materiais, sejam eles móveis ou imóveis, são constituídos por matéria, que é passível de sofrer processos de degradação. Esses processos levam à perda de informações materiais e imateriais e geralmente são decorrentes de reações químicas ou processos físicos, associados ou não à presença de micro-organismos. Eles dependem, além da composição química e da estrutura física do bem, das características do ambiente e/ou microambiente que os cercam. Considerando isso, portanto, e na temática do seminário “Ciência da conservação e o uso de ferramentas de caracterização química, física e biológica de bens culturais”, este artigo trata de como o uso de técnicas de caracterização pode ser feito para avaliar o impacto da composição de microambientes a bens culturais e de como essa avaliação pode auxiliar em sua preservação, utilizando-se de dois estudos de caso.
Vibrational Spectroscopy, Sep 18, 2010
Vibrational Spectroscopy, 2010
Vibrational Spectroscopy, Sep 18, 2010
Neste trabalho - que tem foco na contextualização da química e no impacto que essa atividade pode... more Neste trabalho - que tem foco na contextualização da química e no impacto que essa atividade pode ter na preservação patrimonial e na alfabetização científica - propôs-se, elaborou-se, aplicou-se e avaliou-se uma atividade que objetivou promover o ensino de química por meio do patrimônio cultural ao mesmo tempo em que suscitou a preservação patrimonial e a alfabetização científica na área da química aplicada a bens culturais. O trabalho, desenvolvido por equipe interdisciplinar, fundamentou-se na integração de metodologias de ensino em ciências e de educação para o patrimônio, contemplando o conceitual químico e as implicações sociais e culturais envolvidas no patrimônio. Como resultados, os alunos assimilaram conteúdos de química e demonstraram a apropriação da relação entre ciência e patrimônio. Passaram também a melhor reconhecer o valor e o significado de patrimônio cultural, identificando-se como agentes de preservação e demonstrando o reconhecimento de suas responsabilidades s...
Química Nova, 2016
Paulo (Biblioteca do Conjunto das Químicas), several items were discarded, including apparently m... more Paulo (Biblioteca do Conjunto das Químicas), several items were discarded, including apparently modern worthless large-scale reproductions of paintings by famous painters. A member of staff retrieved these reproductions from the litter bin, one of which was carefully inspected and non-destructively analyzed by spectroscopic techniques (Raman and XRF). The results showed that instead of being a modern reproduction of the gouache "Clinique de Sannois" (Maurice Utrillo, 1923), it was hand-painted probably between the late 1940s and early 1950s using the Jacomet process. This technique was developed by the French printer Daniel Jacomet in the 1920s, who made authorized reproductions of works of art by some of the most celebrated painters of the time.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016
A whitish crystalline-like coating was observed on the surface of the painting "Incêndio", 1990, ... more A whitish crystalline-like coating was observed on the surface of the painting "Incêndio", 1990, produced by Emmanuel Nassar and awarded at the 6th Biennial of Cuenca. This work belongs to the Contemporary Art Museum of the University of São Paulo (MAC-USP) and such coating modified the artwork characteristics, causing an unpleasant effect and compromising its exhibition. The choice of the proper conservation and restoration strategies involves the understanding of the degradation process, demanding the identification of the chemical compounds formed on the painting surface, as well as of the other components in the painting. The results here obtained from Raman and optical microscopies, FTIR-ATR, SEM-EDS and GC-MS, revealed that the efflorescence chemical composition is almost only palmitic acid, with minor contents of stearic acid and their methyl esters, and that the paints are composed by chrome yellow, amorphous carbon and toluidine red pigment; an aluminum silicate filler in the black paint applied on the aluminum ground was also detected. Hierarchical Cluster Analyses (HCA) of the Raman spectra also revealed that the concentration of the efflorescence minor components depends on the paint composition. It was suggested, therefore, that the degradation process resulted from segregation and migration of mainly palmitic acid from the dried paints. Restoration methodologies used in similar cases, as well as factors that contribute to this process, were discussed.
Vibrational Spectroscopy, 2014
In this work the effect of relative humidity (RH) and formaldehyde (H 2 CO) concentration on Pb c... more In this work the effect of relative humidity (RH) and formaldehyde (H 2 CO) concentration on Pb corrosion was investigated; a possible synergism between the aldehyde and CO 2 effects was also considered. Triphasic aqueous salt solutions were used to produce 54% and 75% RH that, together with the 100% RH condition, were combined with 0, 0.62, 55 and 2.0 10 2 mg m −3 formaldehyde concentrations to compose the wanted environments. The results pointed to the conclusion that even at low RH (54%) formates are produced at the metal surface as a consequence of formaldehyde adsorption, indicating that the aldehyde has an active role in Pb corrosion; formates were also observed at relatively low H 2 CO concentration (0.62 mg m −3). No synergism between formaldehyde and carbon dioxide were observed as demonstrated by the Raman images from a corroded Pb coupon, showing that formate and carbonate contributions to the corrosion products were not spatially related. When compared to other volatile organic compounds (VOCs), formaldehyde harmful effect towards metals is frequently underestimated and the results here reported clearly indicate that, even at low RH, its concentration in indoor environments, where it tends to be produced and accumulated, has to be carefully controlled.
Química Nova, 2011
AN EXAMPLE OF RAMAN MICROSCOPY APPLICATION IN THE AUTHENTICATION OF ARTWORKS. In the present work... more AN EXAMPLE OF RAMAN MICROSCOPY APPLICATION IN THE AUTHENTICATION OF ARTWORKS. In the present work, Raman Microscopy was employed in the characterization of the pigments used in a drawing assigned to Tarsila do Amaral, one of the most important Brazilian artists. The work (colored pencil on paper), supposedly produced in the 1920 decade, is of a very simple composition, where blue, green and brown were the colors used. Prussian Blue was found as the blue pigment, whereas green was a mixture of copper phthalocyanine and a yellow dye, probably a diarylide; the brown pigment was a carbonaceous compound. Prussian Blue was replaced by phthalocyanine as pigment since the end of the 1930's and the possibility that it could have been used as pigment in the 1920's can be ruled out.
Heritage
The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest ... more The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest concentration of Indigenous people globally. It represents one of the most extraordinary levels of human, cultural, and artistic diversity, but its material culture is one of the least well-studied. This is especially true in technical art history and conservation science, largely due to (1) the limited international awareness of the richness of materials and techniques used by these Indigenous people and (2) the limitations of knowledge access for many scientists to literature usually published in Portuguese within social sciences and humanities. One result is that these arts are marginalized within technical art history, conservation, and conservation science. To address this knowledge gap, the authors explore 70 materials—among them pigments, dyes, binding media, and varnishes—used for paint production and coloring processes, including syntheses. The authors facilitate research possib...
Heritage, 2023
The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest ... more The Brazilian Legal Amazon region is divided into at least 155 ethnic groups and has the largest concentration of Indigenous people globally. It represents one of the most extraordinary levels of human, cultural, and artistic diversity, but its material culture is one of the least well-studied. This is especially true in technical art history and conservation science, largely due to (1) the limited international awareness of the richness of materials and techniques used by these Indigenous people and (2) the limitations of knowledge access for many scientists to literature usually published in Portuguese within social sciences and humanities. One result is that these arts are marginalized within technical art history, conservation, and conservation science. To address this knowledge gap, the authors explore 70 materials—among them pigments, dyes, binding media, and varnishes—used for paint production and coloring processes, including syntheses. The authors facilitate research possibilities within technical art history, conservation, and conservation science by presenting data from historical texts from the 18th and 19th centuries and more recent scientific literature. The work aims to build a more global, inclusive, and decentralized vision of art history and to create a more pluralistic narrative of Indigenous art history from South America.
Vibrational Spectroscopy, 2014
Abstract Vibrational spectroscopy and GC–MS were used to investigate the effect of MnO 2 and α-Fe... more Abstract Vibrational spectroscopy and GC–MS were used to investigate the effect of MnO 2 and α-Fe 2 O 3 on the degradation of methyl linoleate and vegetal and animal fatty. The metal oxides are among the most employed pigments in rock art paintings, whereas the organic compounds were used to mimic organic binders potentially used in such paintings. Both oxides were very effective in the catalytic oxidation of the organic substrates and light had no significant effect, qualitatively or quantitatively, on the final products. In the case of methyl linoleate without metal oxide, the effect of light (visible) was investigated and it was demonstrated that the samples kept in the dark produced relatively less oxidation products, although the main products were the same (hexanal, methyl 9-oxononanoate and methyl octanoate). In the presence of MnO 2 and α-Fe 2 O 3 methyl 9-oxononanoate was the main product, followed by hexanal. The spectral patterns of the oxidation products were different for manganese and iron oxide and GC–MS demonstrated that more compounds are formed in the former than with α-Fe 2 O 3 . Vegetal and animal fatty presented the same behavior that methyl linoleate did. The results here reported indicated that the two pigments considered actively contribute to fat degradation and the presence of inorganic pigments is the main factor to take into account when organic binders degradation in rock art paintings are investigated.
Química Nova, 2019
The preservation of Cultural Heritage is undoubtedly important for the society, and Conservation ... more The preservation of Cultural Heritage is undoubtedly important for the society, and Conservation Science must dedicate itself to attempts to minimize the inherent processes of degradation to which cultural assets are susceptible. In this context, the evaluation of the chemical aspects of the composition of the objects and their relation with the environment where they are located are essential for the understanding of the decay signs observed, supporting the establishment of effective conservation strategies. These characteristics are demonstrated here by vibrational spectroscopy, scanning electron microscopy and microbiological analysis of efflorescences observed in two types of paintings: a tempera on canvas painting ("Barco com bandeirinhas e pássaros", Alfredo Volpi, 1955) and an oil mural painting of the Throne Room of the National Palace of Mafra (18th-19th century, Mafra, Portugal). The challenges involved in the investigation of the efflorescences are demonstrated in both cases, suggesting the occurrence of degradation processes of different origins: in Alfredo Volpi's tempera on canvas painting, the migration of substances from the preparation layer to the surface of the pictorial layer and microbiological colonization; and in the mural painting the migration of calcium salts from the constituent materials of plaster and of neoformation, besides associated microbiological colonization.
Journal of the Brazilian Chemical Society, 2013
Esculturas policromadas de Pb do Museu do Oratório em Ouro Preto (Minas Gerais, Brasil), expostas... more Esculturas policromadas de Pb do Museu do Oratório em Ouro Preto (Minas Gerais, Brasil), expostas em um mostruário de vidro foram severamente degradadas. Os produtos de corrosão foram analisados por difratometria de raios X (XRD), espectroscopia no infravermelho com transformada de Fourier (FTIR), microscopia eletrônica de varredura (SEM), fluorescência de raios X por dispersão de energia (EDX) e microscopia Raman, e constatou-se a formação majoritária de carbonatos e formiatos de Pb. Embora carbonatos sejam comuns na corrosão atmosférica de Pb, formiatos podem ser formados tanto pela ação de ácido fórmico quanto de formaldeído, sendo sua origem um ponto importante a ser investigado. Simulações ambientais com tiras de Pb expostas a possíveis fontes desses compostos orgânicos voláteis possibilitaram concluir que o processo de degradação foi causado principalmente pelo processo de cura da tinta utilizada na base do mostruário. Contudo, produtos de limpeza, que podem conter formaldeído como conservante, mostraram-se potencialmente capazes de causar danos a objetos de chumbo, acelerando sua corrosão. Polychrome lead sculptures from Oratory Museum in Ouro Preto (Minas Gerais, Brazil) kept inside a glass showcase were severely degraded. The formed corrosion products were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) and Raman microscopy and proved to be mostly Pb carbonates and formates. Although carbonate is a very common finding in Pb atmospheric corrosion, Pb formates can be formed by the action of formic acid or formaldehyde, being their origin a key point to be investigated. Environmental simulations with Pb coupons exposed to possible sources of these volatile organic compounds led to the conclusion that the degradation process was caused mainly by the curing process of the painted showcase baseplate. However, cleaning products, which can also contain formaldehyde as preservative, proved to be potentially harmful to Pb, accelerating its corrosion.
Journal of Raman Spectroscopy, 2021
Cadernos do LEPAARQ (UFPEL)
Nesta curta introdução apresenta-se uma breve contextualização da Arqueometria e um breve relato ... more Nesta curta introdução apresenta-se uma breve contextualização da Arqueometria e um breve relato da realização, atividades e trabalhos apresentados no V Congresso Latino-Americano de Arqueometria (V CLA). Mostra-se quantitativamente as origens dos diferentes trabalhos apresentados (no contexto de seus países), suas áreas de concentração dentro da Arqueometria e as técnicas analíticas empregadas. Comenta-se brevemente, ao final, os trabalhos publicados neste dossiê temático, dentro da presente edição da revista Cadernos do LEPAARQ.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 31, 2018
The physicochemical investigation of ceramics crafted and managed by ancient humans allows a bett... more The physicochemical investigation of ceramics crafted and managed by ancient humans allows a better understanding of their social, technological, economical, routine and artistic activities. The Brazilian State of Rio Grande do Sul presents the biggest number of registered archaeological sites in the country, and many of them are earthen mounds, locally known as cerritos de indios. This kind of archaeological site is of utmost importance to understand the social development of the biome Pampa - including areas from Brazil, Argentina and Uruguay - and almost nothing is known about the physicochemical composition of the artifacts from the Brazilian portion. In this work we investigated the mineral phases present in archaeological ceramics from the cerrito Pavão I (PSG-20) by means of white light microscopy (petrography), Raman micro-spectroscopy, XRD and XRF spectroscopies, and FTIR-ATR. Different minerals were identified and allowed to propose a firing temperature of ca. 500-650 °C. ...
Revista CPC
Bens culturais materiais, sejam eles móveis ou imóveis, são constituídos por matéria, que é passí... more Bens culturais materiais, sejam eles móveis ou imóveis, são constituídos por matéria, que é passível de sofrer processos de degradação. Esses processos levam à perda de informações materiais e imateriais e geralmente são decorrentes de reações químicas ou processos físicos, associados ou não à presença de micro-organismos. Eles dependem, além da composição química e da estrutura física do bem, das características do ambiente e/ou microambiente que os cercam. Considerando isso, portanto, e na temática do seminário “Ciência da conservação e o uso de ferramentas de caracterização química, física e biológica de bens culturais”, este artigo trata de como o uso de técnicas de caracterização pode ser feito para avaliar o impacto da composição de microambientes a bens culturais e de como essa avaliação pode auxiliar em sua preservação, utilizando-se de dois estudos de caso.
Vibrational Spectroscopy, Sep 18, 2010
Vibrational Spectroscopy, 2010
Vibrational Spectroscopy, Sep 18, 2010