Study of materials and techniques in painted ceiling panels from a palace in Cremona (Italy, 15th century)

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Processos coletivos de formação socioambiental: para além das palavras, mas a partir de suas raízes

Este texto aborda parte de uma pesquisa de doutoramento queobjetivou compreender e elaborar a dialética de uma ação formativadesenvolvida pelo autor: o curso de formação de agentes locais de sustentabilidade,promovido pela Universidade de São Paulo e financiado por uma empresade celulose e papel. Partiu-se da hipótese de que a pouca dedicação àdimensão teórica obstruía a dialética teoria-prática no pensamentolinguagemdo autor. Desenvolveu-se um estudo filológico a partir dasnoções de dialética, filosofia da práxis e pedagogia, interrogando-se sobreo conceito de práxis. Pôde-se compreender a importância da herançamarxista e das críticas que esta vem recebendo para o favorecimentode uma vertente crítica e emancipatória em educação ambiental. Concluiseque o conceito de práxis, compreendido como a ação intersubjetiva quefavorece simultaneamente a autonomia individual e coletiva, permitiu areinterpretação da trajetória do autor como uma etapa necessária daprópria dialética que buscou compreender

Sobre conflitos ambientais e educação ambiental

O presente artigo apresenta e discute algumas possibilidades de abordagem dos conflitos ambientais a partir de uma educação ambiental crítica, contextualizando as trajetórias e escolhas políticas e metodológicas que favorecem alguma convergência entre ambos os campos de pesquisa e ação. Para tanto, considero os conflitos ambientais como conflitos sociais, apresento três diferentes visões sobre os conflitos e elejo uma delas como a mais próxima da vertente da educação ambiental crítica, provocando uma reflexão sobre democracia e política, diferenciando as noções de pluralidade social e desigualdade social. A partir destes pressupostos, destaco uma das possibilidades de conceituação dos conflitos ambientais. Na ultima parte, levanto algumas questões metodológicas para maior coerência na aproximação destes campos e aponto alguns eixos para o debate, sugerindo também materiais e outras fontes de informações para aprofundamento

Improving Wood Resistance to Decay by Nanostructured ZnO-Based Treatments

In this study, the maple wood surface was coated with nanostructured zinc oxide, grown on the surface by using a hydrothermal process, and furtherly treated with shellac varnish. Samples obtained both after ZnO treatment and after the final varnish application were characterized by different techniques, i.e., X-ray diffraction (XRD), scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS), micro-FTIR with attenuated total reflectance (μ-ATR-FTIR), chromatic variation measurements, and contact angle determinations. Analytical results showed that the wood surface was covered by quite a homogeneous array of inorganic nanoparticles and that the natural resin forms a regular film over the ZnO nanostructures. An accelerated aging test was used to evaluate the protecting effectiveness of the treatments towards UV-induced decay of wood material. After the test, wood treated with ZnO and with the shellac/ZnO combination underwent a considerably lower chromatic change if compared to the untreated wood, suggesting an enhanced resistance of the treated maple to the decay due to light exposition. The presence of nanostructured ZnO protects from decay not only the wood substrate but also the shellac film. A microbiology test showed that growth of fungal species, e.g., common mold, is prevented on the wood surface treated with ZnO or with shellac/ZnO, indicating that the nanostructured zinc oxide also provides an effective protection from biodeterioration. The coating obtained by consecutive application of nanosized ZnO particles and shellac varnish combines the excellent aesthetical features and water repellence of the traditional finish with the protecting effectiveness of the nanostructured inorganic component

The exemplary case of a remarkably well-preserved historical musical instrument: the “Tuscan” Stradivari violin (1690)

In recent years, scientific diagnostic analysis has increasingly focused on historical musical instruments, especially bowed stringed ones. The materials composing the stratigraphy of these peculiar works of art are characterized by a complex and heterogeneous nature, which is representative of the working techniques employed by the great violin makers of the past. The entire coating system, so called wood finish [1], includes multiple varnish layers on a previously grounded wooden substrate to prevent varnish penetration. Over the time, however, the original stratigraphy of these centuries-old masterpieces could have been affected by the extended handling during performances and practice, the very close contact of the instrument with the musician skin, or, again, accidents and interventions of maintenance and restoration. As a consequence, variations in its coating thickness and composition have most often occurred. The object of the present study is one of the best-conserved instruments by Antonio Stradivari, namely the “Tuscan” violin (1690) today preserved at the Accademia of Santa Cecilia in Rome (Italy). Commissioned by the Medici family in 1684, as a part of the famous quintet, it is one of the earliest examples of the master’s multiple-layer varnishing method [2]. The remarkably well-preserved wood finish of the violin was non-invasively studied by UV-Induced Fluorescence (UVIFL) photography (by B. Brandmair), Fourier-Transform Infrared (FTIR) reflection spectroscopy and X-Ray Fluorescence (XRF) spectroscopy. The hypothesis drawn from the non-invasive approach was supported by a micro-destructive analysis performed on two micro-samples, one taken from the violin’s top plate (Fig. 1) and the other from the centre bass rib. The micro-samples were analysed by the Optical Microscope (OM) equipped with visible and ultraviolet lights and by the Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray (EDX) spectrometer. The aim of the multi-analytical investigation was the characterization of varnishes, pigments and wood treatments constituting the violin’s stratigraphy, trying to understand the methods used by Antonio Stradivari to finish the instrument. From the results, the varnish is confirmed to be applied in a two-layer system: the uppermost salmon-fluorescent coloured varnish (Fig. 1, level A) is oil-resinous composed, with crystals of calcium oxalates witnessing the age of the varnish as a decomposition product of lipid materials [3]; the lowermost yellow-whitish fluorescent layer (Fig. 1, level B) is also characterized by an aged oil-resinous varnish with an aluminium- and oxygen-rich grain dispersed therein which gives rise to possible attributions, including that of alumina (Al2O3) as a substrate for lake pigments [4]. At the interface between the wood and the overlying varnish (Fig. 1, level C), probably related to a wood treatment, a proteinaceous compound can be likely identified as a binder of a few silica and silicates mineral phases. Moreover, rare particles of possible titanium-manganese-iron oxides and/or hydroxides as well as iron-containing aluminosilicates, both suggesting the possible presence of iron-based pigments such as red-ochre or umber earth [5], were found at this level. Under the treatment level, finally, small amounts of chlorine, sulphur, potassium and calcium could be ascribed to a wood pre-treatment method [2]. In conclusion, by combining data from the non-invasive and micro-destructive analytical campaign it was possible to propose a stratigraphic hypothesis of the “Tuscan” violin

“I Cantieri del Suono” project: a public-private cooperation for the valorization of the violin “Piccolo” by Lorenzo Storioni (1793)

The Cultural District of Violin Making is a network of Cremona municipality that keeps the search for quality violinmaking alive and constantly strives to defend traditional craftsmanship. It coordinates various groups in the city involved in education, teaching and research in the field of music and violinmaking. The Bracco Foundation, one of the leading arts patrons in Italy, has chosen to finance the “I Cantieri del Suono” project, dealing with this highly promising area. One of the projects aims consists in the acquisition and valorisation of a rare violin made by Lorenzo Storioni (Cremona, 1744-1816), involving all the main organisations in the District, plus the violin makers that work in the city of Cremona. This small-size violin, known as “Piccolo”, was probably made for a child. The instrument was played in the decades following its construction (1793), but then it has not been used for a significant period. It provides an extraordinary piece of evidence when it comes to construction techniques, the materials used and the composition of varnishes in late eighteenth century Cremona. The analytical protocol developed at the Laboratorio Arvedi di Diagnostica non Invasiva allowed collecting new data on the instrument through a non-invasive approach (XRF and FTIR spectroscopy, X-ray radiography, VIS-UVIFL photography, 3D laser scanning, OCT, NMR). The obtained results were discussed with the students of the Master’s degree in Conservation and Restoration of Cultural Heritage, aiming at identifying the best procedures to preserve the instrument and its materials. Meanwhile, the students of the International School of Violin Making took advantage from 3D model, making a playable copy of the instrument. The violin and its copy will soon enrich the Civic Collections and will be exhibited at the Museo del Violino in Cremona. Up to now different strategies of communications have been put in place (publication of a monography, social network notifications, congress for experts in the field). During the exhibition, attention will be given to the diagnostic results, accompanying visitors through different levels of technical insights

Stradivari's Varnish Revisited: Feature Improvements Using Chemical Modification

The most widespread varnish formulations used by master violin-makers of the "Italian Golden Age", including Antonio Stradivari, were based on mixtures of siccative oils (e.g., linseed oil) and natural resins (e.g., colophony). Similar formulations are still used for the finish of contemporary instruments. Although most precious violins made by Stradivari and other Cremonese Masters are kept in museums, several instruments are still played and their finish may undergo deterioration due to contact with the players. Moreover, the decay of the traditional varnish may occur due to mechanical stress and natural aging caused by environmental agents (e.g., exposure to uncontrolled light, humidity, and temperature changes). The main aim of this research work is to investigate the possible improvement of varnish resistance to the decay induced by different aging processes. For this purpose, the traditional varnish (linseed oil/colophony 3:1 w/w) was recreated in the laboratory following an ancient recipe and then it was functionalized with a cross-linking agent (3-Glycidyloxypropyltrimethoxysilane, GLYMO). Plain and functionalized varnishes underwent artificial aging (UV light, temperature, and humidity variations), and their properties were comparatively studied using different techniques. All the results suggest that the functionalized varnish displays improved resistance to the aging process and particularly enhanced photostability and increased hardness (resistance to scratches)