A new bio-based organogel for the removal of wax coating from indoor bronze surfaces

Abstract In this research, we propose an advanced system for the cleaning of wax-based coatings applied on indoor bronzes. To this aim we developed a new kind of eco-friendly gel based on PHB (poly-3-hydroxybutyrate) used as thickening agent, biodiesel (BD) and dimethyl carbonate (DMC). BD is a mixture of methyl esters obtained from palm oil, which acts as cleaning agent while DMC was added as additional solvent to partially solubilize PHB and forming a gelly phase. For the first time a PHB-based gel obtained by mixing two solvents with different proprieties was proposed, expanding the range of possible formulations, that can be used according to the specific restoration purpose. After the preliminary characterization of chemical and physical properties of the gel, an ad hoc analytical protocol was implemented to evaluate both the cleaning efficiency and the release of residues on the treated surfaces. Standard samples were prepared following ancient recipes and submitted to spectroscopic and chromatographic analysis before and after the cleaning procedures. Finally, the performances of PHB-DMC/BD gel were assessed on a real case of study presenting a wax-based coating: the Pulpito della passione attributed to Donatello and dated back to 1460. In situ analysis demonstrated the high cleaning efficiency of the proposed systems also for the removal of aged coatings

Atomic spectrometry update: Review of advances in the analysis of metals, chemicals and materials

There has been a large increase in the number of papers published that are relevant to this review over this review period. The growth in popularity of LIBS is rapid, with applications being published for most sample types. This is undoubtedly because of its capability to analyse in situ on a production line (hence saving time and money) and its minimally destructive nature meaning that both forensic and cultural heritage samples may be analysed. It also has a standoff analysis capability meaning that hazardous materials, e.g. explosives or nuclear materials, may be analysed from a safe distance. The use of mathematical algorithms in conjunction with LIBS to enable improved accuracy has proved a popular area of research. This is especially true for ferrous and non-ferrous samples. Similarly, chemometric techniques have been used with LIBS to aid in the sorting of polymers and other materials. An increase in the number of papers in the subject area of alternative fuels was noted. This was at the expense of papers describing methods for the analysis of crude oils. For nanomaterials, previous years have seen a huge number of single particle and field flow fractionation characterisations. Although several such papers are still being published, the focus seems to be switching to applications of the nanoparticles and the mechanistic aspects of how they retain or bind with other analytes. This is the latest review covering the topic of advances in the analysis of metals, chemicals and materials. It follows on from last year's review1-6 and is part of the Atomic Spectrometry Updates series

Analisi strategica alla base di una IPO: il caso Rosss S.p.A.

Il lavoro intende analizzare il percorso di quotazione di una impresa, partendo dall'interpretazione delle strategie razionali e irrazionali alla base della decisione, nonché gli effetti generati sull'intero sistema aziendale. A tal fine, si è ritenuto interessante esaminare l'iter di quotazione intrapreso dall'impresa ROSSS S.p.A., esempio tipico di azienda a conduzione familiare all'interno del contesto italiano: l'analisi induce ad un'interessante riflessione sui motivi che hanno spinto il soggetto economico verso tale scelta e sui conseguenti effetti

Searchable databases for the identification of organic colorants using surface-enhanced Raman scattering (SERS) : critical evaluation and possible approaches

Organic colorants have been used for millennia as textile dyes and as pigments for paintings and other kinds of polychrome works of art. Even today, natural and synthetic organic dyes are of great interest in the forensic field as food colorants, ink components and textile dyes. As they are often present in art objects in minute amounts due to their high coloring power, their identification is really challenging. High-performance liquid chromatography (HPLC) and UV-visible spectroscopy have been routinely employed to detect dyes, but they require sizable samples. During the last few years, a lot of research in this field has been carried out by surface-enhanced Raman scattering (SERS), which has proven to be an extremely effective technique because of its great sensitivity. Although the development of several micro-invasive analytical procedures has recently expanded the applicability of SERS spectroscopy in the art conservation and forensic fields, the necessity of obtaining a reliable match between spectra from unknowns and reference materials in a fast and convenient way is still to be fulfilled. In this context, the availability of extensive spectral databases as well as the accessibility of library search methods designed to match a query spectrum to the closest library references would significantly increase the spectral recognition rate, making the entire identification process considerably easier. In the present work, a number of pure colorants, extracts from plants and insects, fragments from dyed paper and textiles, as well as lakes and glazes from several works of art were characterized by FT-Raman, ordinary Raman and SERS spectroscopies in different experimental conditions, and the spectra thus obtained were then used to build a searchable library. Preliminary attempts to classify query spectra against the library clearly showed that the search process is strongly affected by spectral variations which are completely unrelated to the identification goal, such as the amount of fluorescence, the background shape and the signal resolution. Improved results were achieved by searching against a second library, in which all the spectra were subjected to baseline correction and selective exclusion of certain spectral regions. Multivariate analysis methods, such as principal component analysis, will be applied to the spectra acquired thus far and evaluated to further improve the classification process and provide an easy, fast and reliable way to identify unknown dyes

La protezione di manufatti in argento: imaging della luminescenza visibile indotta da UV per l’individuazione di vecchie vernici e il controllo delle nuove stesure

applicazione sperimentale dell'imaging in luminescenza visibile indotta da uv per il mapping delle stesure di vernici nel restauro di manufatti d'argent