1,721,008 research outputs found
La conservazione del patrimonio moumentale: prodotti consolidanti impiegati nelle operazioni di restauro
No full textIdentification of complex structures of paintings on canvas by NMR: Correlation between NMR profile and stratigraphy
No full textPaintings on canvas are complex structures created by superimposing layers of different composition. Investigations on the structure of these artworks can provide essential information on their state of conservation, pictorial technique, possible overpaintings, and in planning a proper conservation plan. Standard methods of investigation consist in sampling a limited number of fragments for stratigraphic analyses. Despite the recognized validity of these methods, they are affected by evident limitations. Nuclear magnetic resonance (NMR) profiling, often named NMR stratigraphy, is an NMR relaxometry technique applied by single-sided portable devices developed to overcome the disadvantages of microinvasive stratigraphic analyses. The potential of this approach on artworks, including wall paintings and a few examples of painted canvas, is described in the literature. In this study, NMR profiles of painting on canvas were examined by analyzing transverse relaxation time data by T2 quasi-continuous distributions and the results compared with standard stratigraphic cross-sections analysis. Combining signal intensity and T2 quasi-continuous distributions, the identification of textile, preparatory, and paint layers was enhanced. The diction “NMR stratigraphy” for these inhomogeneous layered artworks is also discussed. Indeed, unlike the stratigraphic cross-sections, NMR profiles provide information on a volume (flat slice), rather than on a surface, and the collected signal can derive from nonuniform and partially overlapping layers. This study paves the way for extensive investigations on relaxation time quasi-continuous distributions in various binder/pigment mixtures in order to improve the reliability of NMR profile as an innovative, non–invasive, and nondestructive method for analyzing paintings on canvas
Effects of atmospheric NOx on biocalcarenite coated with different conservation products
No full textOne of the most important factors of calcareous stone decay is the chemical attack caused by atmospheric pollutants dissolved in water, in particular acidic gases such as SOx, NOx and CO2. The treatment of stone artefacts with hydrophobic products reduces the water uptake of the rock and is, therefore, considered a "protective treatment". The aims of the present study were the observation of the effects of NOx on a biocalcarenite (Lecce stone) and the evaluation of the performance of protective products (Paraloid B72 and a fluoroelastomer) normally used in stone conservation. A system for the simulation of accelerated ageing has been assembled and the Lecce stone samples, treated with polymeric products, have been exposed to NO2 (nearly 1 ppm) during thermo hygrometric cycles. The nitrite and nitrate salts formed on the specimens have been determined by ion chromatography. Both the polymeric products tested have given high hydrophobic properties to the stone, even if they do not assure satisfactory protection toward NO2 exposure. Actually, their protective efficacy, or ability to reduce the acidic attack of NO2, quickly decreases when the ageing period increases. Paraloid B72 seems more effective than fluoroelastomer because, on the samples treated with the latter, higher amounts of nitrites and nitrates have always been detected. In contrast, non-treated samples - used as reference - have shown a constant increase in the amount of nitrates and nitrites during ageing. However, the surface analyses of the stone samples, by environmental SEM and μ-laser profilometry, did not show any change in superficial morphology after the ageing, suggesting that NO2 acts inside the pores
Indagine conoscitiva sullo stato di conservazione dei materiali lapidei presenti sulla facciata di S. Maria del Fiore - Firenze
No full textPerfluoropolyethers isobutylamide and isobutylester. Performance in the protection of stones
No full textLa conservazione del patrimonio monumentale. Protettivi impiegati nella conservazione dei materiali lapidei: storia, impieghi, sviluppi
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Indagini diagnostiche e restauro della statua lignea di SAN NICOLA DI MIRA
No full textThe restoration of the wooden
statue of San Nicola di Mira –
usually known as San Nicola di
Bari – at the Diocesan Museum
of Palermo, is the result of a cooperation
among art historians,
restorers, physicists, chemists,
biologists and geologists. The intervention
was carried out by following
a series of historical and
scientific surveys which allowed
to study the object in depth and
to recover it its originality. The
restoration took place in a hall
of the Diocesan Museum, fitted
out as a laboratory, according to
rigorous scientific rules and to
Cesare Brandi’s restorationtheory.
So, the statue went back,
as far as possible, to its ancient
splendour; moreover, some details
re-emerged, that had been
so far buried under the patinas
of the past
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