Search

This paper focuses on the analysis of buildings used for tobacco processing, built in the first half of the 20th century in Tuscany (province of Arezzo), by studying construction techniques, materials, and preservation issues. Since the 16th century, in Tuscany, the sites involved in the cultivation of tobacco are both the upper Val Tiberina and Val di Chiana (in particular Arezzo and Siena areas). At first, tobacco was used either for medical purposes or as snuff and pipe powder. It soon became the most renowned cultivation throughout the Tiberina Valley, due to the excellent quality of the tobacco produced. The first significant crops date back to the early 17thcentury. The drying process took place in specific buildings named "tabaccaie", where tobacco leaves were placed over an oak wood fire to dry. This process was adopted until the 1970s. Subsequently, a profound crisis in the agricultural sector determined the falling into disuse and abandonment of numerous "tabaccaie". In some cases, these buildings have been reused as luxury hotels for tourism purposes, but many of them have been demolished or are in a state of ruin. They represent the testimony of agro-industrial vernacular architectures nowadays at great risk. Indeed, most of the recovery interventions have often completely obliterated the original structure to make the former “tabaccaie” able to satisfy housing and comfort requirements. The study aims to deepen the knowledge of these buildings to preserve cultural identities and transfer inherited values.

A portable hyperspectral sensor collects reflectance spectra in the 350-2500 nm range, allowing the identification of not only inorganic but also organiac materials. In this paper, a non-invasive and non-destructive characterization of pictorial binders was used. The results show that their main spectral differences are located between 1200-2400 nm. It is also indicated that when a binder is mixed with colorants, some modifications occur in respect to its original spectrum. In addition, the first derivative transformation of original spectra allows an easier identification of these organic binders, where the most discriminating regions are 1160-1250 nm and 1660-1800 nm., Estudos de Conservação e Restauro, n. 9 (2018)

This work was focused on the preparation of a new protective agent with low average molecular weight containing short pendant perfluoropolyether segments linked to an oligosuccinamide chain in order to achieve: (i) high hydrophobic effect and photo-stability, (ii) good adhesion to the rock through the polar amidic groups, (iii) excellent distribution on the pore walls surface without their blockage, (iv) solubility in environmental friendly solvents. Hydrophobic penetration and distribution properties of the compound applied on a biocalcarenite (Lecce stone), have been investigated by Nuclear Magnetic Resonance (NMR) Imaging, Profiling and Diffusometry of 1H nuclei, and compared with a perfluorinated commercial product. These NMR techniques has been proved to be a valid non-destructive and non-invasive technique for monitoring the conservation state and water absorption in materials and objects of interest to cultural heritage, as well as for evaluating the efficiency and distribution of protective or consolidation treatments.

The internal distribution of water-repellent products applied to surfaces to make a porous material repellent is of great interest in the field of the safeguard of cultural heritage items such as stone buildings, statues and frescos. Water is the main cause of degradation of porous materials exposed to rain, moisture and air pollutants. In previous papers[1], it has been shown how MRI allows one to evaluate and compare the performance of products and treatments used. Those products were commercial ones, made for different uses than cultural heritage items protection. In the middle of the ‘80s, the group of CNR in Florence started to synthesize mono-biand tetra-functionalized perfluoropolyetheric compounds for the specific use in the protection of stone, with the following properties: (i) stable to chemical agents, heating and UV irradiation; (ii) high water-repellency; (iii) ability to perform treatments in such a way that the natural permeability of stone to air and water vapor is not significantly reduced; (iiii) chemically inert with the stone substrate, and therefore completely reversible. Unfortunately, the best products synthesized were soluble in Chlorofluorocarbons. Now, new products containing a perfluoropolyetheric and hydro-alcoholic solvents, but not soluble in water or Chlorofluorocarbons. Their hydrophobic and penetration properties have been investigated by MRI images, taken on biocalcarenite samples treated with commercial and new fluorinated compounds, at increasing times during capillary water absorption. The presence of water inside each sample could be visualized and the height reached by the wetting front quantified as a function of time. The images were analyzed by an in-house software able to identify the front by an objective criterion. The images show the different protection efficiency of products and treatments. Good fits to the data were obtained with theoretical and empirical models of absorption kinetics, starting from the Washburn model. The data analysis gives us parameters useful to quantify the effects of the treatments on the capillary properties. The results demonstrate the better performance of the new fluorinated compounds able to preserve stones and environment. [1] M. Gombia et al., J Appl Phys, 103, 094913 (2008).

Immagini MRI di sezioni interne di materiali porosi consentono di valutare l’efficacia di prodotti e trattamenti protettivi al fine di ottimizzare protocolli di intervento. Sono stati sintetizzati prodotti contenenti blocchi perfluoropolieterei, solubili in alcol e in solventi idroalcolici, ma non in CFC. Mediante MRI quantitativa ed un software sviluppato ad hoc é stato possibile determinare l’altezza del fronte di imbibizione dell’acqua in campioni di biocalcarenite trattati con questi prodotti e con altri commerciali. Sono stati ottenuti buoni fit dei dati a modelli ottenuti partendo dal modello di Washburn [1]. I risultati dimostrano la migliore efficacia dei nuovi prodotti, non dannosi per l’ambiente. [1] M. Gombia, V. Bortolotti, R.J.S. Brown, M. Camaiti, P. Fantazzini J Appl Phys 103 (2008) 094913.