1,720,963 research outputs found
Non-invasive identification of organic materials in historical stringed musical instruments by reflection infrared spectroscopy: a methodological approach
No full textThe analysis of historical musical instruments is
becoming more relevant and the interest is increasingly moving
toward the non-invasive reflection FTIR spectroscopy,
especially for the analysis of varnishes. In this work, a specific
infrared reflectance spectral library of organic compounds was
created with the aim of identifying musical instrument materials
in a totally non-invasive way. The analyses were carried
out on pure organic compounds, as bulk samples and laboratory
wooden models, to evaluate the diagnostic reflection midinfrared
(MIR) bands of proteins, polysaccharides, lipids, and
resins by comparing reflection spectra before and after the KK
correction. This methodological approach was applied to real
case studies represented by four Stradivari violins and a
Neapolitan mandolin
On the Use of Overtone and Combination Bands for the Analysis of the CaSO4-H2O System by Mid-Infrared Reflection Spectroscopy
No full textNon-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy
No full textIn this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome art-works analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the v(s)(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks
A multi-analytical non-invasive approach to violin materials: The case of Antonio Stradivari “Hellier” (1679)
No full textThe study and characterization of the materials of historic musical instruments, especially violins, represent an
important aim for scientists and conservators. In particular, the varnishes have been often investigated, even to
correlate their chemical characteristics with the sound produced by instruments. However, in the last years,
the attention has moved to the study of those materials (inlays, pigments, binders, fillers, glues) used by important
ancient violin makers, as Antonio Stradivari, to decorate the musical instruments in order to confer a higher
aesthetic value. Because of the importance of the ancient violins, the analytical investigations have to be performed
more and more with non-invasive methodologies, and this could be a strong shortcoming for the complexity
of the materials to study. Therefore, the scientific research has improving new methodological
approaches that could provide several results without touching the violins. The “Hellier” violin (1679), actually
held in Museo del Violino of Cremona (Italy), is one of the most important violin made by Antonio Stradivari
and represents a perfect example for the study of both varnishes and decorations. This contribution focuses on
the materials' characterization through different totally non-invasive diagnostic techniques: UV-induced visible
fluorescence imaging, optical microscopy, reflection FTIR spectroscopy, and XRF spectroscopy. In particular, reflection
infrared spectroscopy has been applied for the characterization of several organic substances historically
used to make the musical instruments, with the aim of achieving a correct interpretation of the violin varnish
spectra. The varnishes, the black strips of the purflings, the black fillers, and the white decorations of the inlays
were investigated. The preliminary results suggest the presence of (i) supposed resinous drying oil varnish, (ii)
metal-based ink used to dye the black filler of the inlays and the black strips of the purflings, and (iii) bone or
ivory as material for the white decorative elements of the inlays
The Book of Kells: A non-invasive MOLAB investigation by complementary spectroscopic techniques
No full textThis paper highlights the efficacy of non-invasive portable spectroscopy for assessing the execution technique and constituent materials in one of the most important medieval manuscripts, the Book of Kells. An aimed campaign of in situ measurements by the MObile LABoratory (MOLAB) has analyzed its elemental composition and vibrational and electronic molecular properties. The ample analytical toolbox has afforded complementary diagnostic information of the pigment palette permitting the characterization of both inorganic and organic materials as pigments and dyes in the white, purple, blue, red, orange, green and black areas. in particular, the novel widespread use of calcinated gypsum (anhydrite) as both a white pigment and in correlation to the organic dyes in this manuscript has been noted. The non-invasive identification of the organic dye orchil is significant considering its rare non invasive detection in medieval manuscripts. Finally the occurrence of particular alterations of the organic black areas giving rise to calcium carboxylate and calcium oxalate has been specifically highlighted. importantly, this work elaborates complex aspects of the employed painting materials which have given rise to numerous significant points of interest for a more elaborate understanding of this irish treasure
Caratterizzazione dei materiali pittorici del Polittico della Misericordia mediante analisi non invasive
No full textOn the Use of Overtone and Combination Bands for the Analysis of the CaSO<sub>4</sub>—H<sub>2</sub>O System by Mid-Infrared Reflection Spectroscopy
No full text With the aim of characterizing ground preparations of paintings by infrared reflection spectroscopy, the CaSO4–H2O system (gypsum/bassanite/anhydrite) has been re-investigated, evaluating and assigning the SO42- and OH overtone and combination bands, respectively, in the ranges 1900–2700 cm−1 and 5000–6000 cm−1 resulting from reflection and high concentration transmission spectra. The second-order modes have been proven to be highly specific, reliable, and less affected by overlap with bands of organic binders and can hence be exploited for the identification of the sulfate hydration phase using infrared (IR) reflection spectroscopy. Subsequently, the characterization and identification of hydration phases in unknown sulfate-based ground preparations on authentic artworks have been carried out noninvasively by fiber-optic reflection IR spectroscopy and on cross-sections by infrared reflection micro-spectroscopy. The spectroscopic data collected both on standards and artworks have been cross-validated by X-ray diffraction. </jats:p
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
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