1,721,020 research outputs found
PL micro-imaging supported by FTIR mapping for the study of historical musical instruments
No full textCoatings in historical bowed string instruments made in Cremona (Italy) during 17th and 18th C. are often multi-layered systems, where organic binders are variously mixed with inorganic materials to enhance the sound and the aesthetic features of the objects. These materials were applied in superimposed coats in order to seal the wood porosity and prepare the surface to the application of the external varnish.
In this work, we propose to employ photoluminescence (PL) micro-imaging, with hyperspectral resolution, and FTIR mapping to fully characterize the different layers of the multi-layered system, with a specific focus on the interface between the ground coat and the wood
Le vernici e i trattamenti superficiali di strumenti musicali ad arco prodotti a Cremona tra il XVII e il XVIII secolo: indagini non-invasive e micro-invasive
No full textGiacomo Fiocco, Monica Gulmini, Tommaso Rovetta, Curzio Merlo, Marco Malagodi
No full textEight fragments obtained from historical
instruments produced in Cremona (Italy) during the
17th and 18th century have been considered. Both noninvasive
and micro-invasive instrumental techniques
were carried on to directly highlight the treatments
employed on the wood before varnishing. Scanning
Electron Microscopy performed on cross sections
highlights the presence of two different methods of
wood treatment, in order to inhibit the penetration of
the varnish into the porous structures. In one set of
fragments, the wood was treated with a filler made
with gypsum dispersed in an organic medium. A
mechanical treatment or a digestion of the wood
structures with a basic solution, which caused a
collapse of superficial tracheary elements, was
employed on the other fragments
Non-invasive identification of red and yellow oxide and sulfide pigments in wall-paintings with portable ER-FTIR spectroscopy
No full textScientific interest in analytical tools that enable reliable, repeatable, and rapid measurements without sampling is growing in the field of cultural heritage. Therefore, improving the use of methods that permit an efficient characterization of a wide range of materials through non-invasive and portable instruments, such as spectroscopies, is currently in high demand. This work is focused on the non-invasive study and identification of selected red and yellow pigments containing oxides and sulfides, frequently used in ancient wall-paintings, by means of portable External Reflectance Fourier Transform Infrared spectroscopy (ER-FTIR) within an extended spectral range (7500 - 360 cm−1) which includes a portion of far IR addressing diagnostic peaks and band assignment for the first time. In this work we have also examined the reflection signals of the pigments when applied on a surface representing a fresco wall-painting, to discuss possible changes of the profile as the optical and morphological properties of the surface change. For this purpose, yellow and red oxides, ochres, Siennas, minium, orpiment, and vermillion were selected and used to produce laboratory mock-ups of fresco paints. The ER-FTIR signals obtained on raw pigments were firstly validated by portable non-invasive Raman spectroscopy and X-Ray Fluorescence, and bench-top X-Ray powder Diffraction. Then, the results were subsequently compared with the ER-FTIR signals collected on the mock-ups to discuss the changes in the reflection spectral profile when in presence of rough surfaces and matrix-effects. The combined study on reference materials and mock-ups allowed to identify and discuss ER-FTIR marker bands which were finally validated on real samples of three fragments of Roman frescos provided by the Archeological Museum “San Lorenzo” in Cremona. The proposed method demonstrates distinctive IR features from external reflection analysis on the selected pigments, scarcely studied by portable FTIR instruments, offering a decisive advancement for in situ analytical characterization of the pigments used in wall-paintings
Surfing through the coating system of historic bowed instruments: a spectroscopic perspective
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Toward a better knowledge of Beethoven's creative process through the ink characterization: A non-invasive study of the sketchleaves held at the Civic Library in Bergamo (Italy)
No full textLudwig van Beethoven (1770 -1827) used to record his ideas in sketchleaves and sketchbooks, where he collected preparatory materials before publishing his final work. These handwritten documents are rich in information. Nonetheless, as a consequence of the creative process, the annotations are much reworked by the composer itself, making them hard to interpret. This study aims, for the first time, at a non -invasive characterization of the inks used by Ludwig van Beethoven in his manuscripts. Distinguishing the inks used for the notes and the rewritten or modified parts would allow a better comprehension of his creative process. With this purpose, the manuscript BG0044 Piatti-Lochis PREIS.J1.9686, held at the Angelo Mai Civic Library of Bergamo (Italy), was investigated by exploiting portable imaging and spectroscopic techniques. The photographic documentation under Visible (VIS) and Ultraviolet light (UVIF) illumination, along with the Hyperspectral Imaging (HSI) in the spectral range 450 nm to 1000 nm were essential to identify the areas of interest for further analysis and provide a working hypothesis on the inks used by Beethoven. Afterwards, X -Ray Fluorescence (XRF) spectroscopy was employed to get an insight into the chemical composition of the inks. The foremost result revealed the presence of two different iron-based inks, used for the staves and the handwritten musical notations, respectively. The superimposed strokes observed among the staves on the same material composition led us to suppose that they have been applied immediately to the paper or in a limited time during which the same ink recipe was maintained. Hence, it seems that the composer made changes almost at the same time as he wrote the first version. These results represent the first scientific evidence to endorse the hypothesis of a rapid change of mind in his writing process
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