1,721,099 research outputs found
Dimethyl carbonate as a novel methylating reagent for fatty acids in analytical pyrolysis
No full textNew Frontiers in Application of FTIR Microscopy for Characterization of Cultural Heritage Materials
No full textWe present an overview of recent advances in the application of Fourier Transform Infrared (FTIR) microscopy for analysis of complex, multicomponent, and multilayer samples such as those typically encountered in the field of heritage materials. This technique is particularly useful since it allows identification and localization of both organic and inorganic (if IR active) compounds. New improvements have been possible thanks to the introduction of ad hoc sample preparation methods to obtain either thin or cross sections that allow both avoidance of contamination from organic embedding resin and improvement of the quality of the acquired spectra. Moreover, integrated use of spectra registered in the near-infrared (NIR) and mid-infrared (MIR) regions allows better comprehension of cross section composition. Data interpretation has been improved thanks to the development of chemometric methods for elaboration of hyperspectral data. A new and very promising field is the development of enhanced FTIR methods for detection of trace components in microextracts. These systems, allowing detection of extractable organic compounds from about 0.1 mg of sample, will be extremely useful in the future for analysis of natural and synthetic colorants, varnishes extracted, for instance, from cotton swabs used during cleaning of paintings, and organic residues on archeological remains
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
SCIENTIFIC EXAMINATION FOR THE INVESTIGATION AND CONSERVATION OF FAR EAST ASIAN MURAL PAINTINGS
No full textIf compared to western wall paintings, the study, conservation and restoration of far east Asian wall paintings is a more difficult task, owing not only to the varied supports and painting material constituents they are made of, but also to the particular social environments in which they are located and the consequences it has on the adopted theoretical and practical approaches to conservation. For instance, in some countries an element of devotion and the desire to offer the best to the gods leads religious communities to rebuild damaged sections of structures instead of trying the preserve them.
Therefore, when talking about far east Asian mural paintings conservation the main issue is their imminent risk of loss or damage. This has sometime led to certain standardization of treatments (pigments, consolidants, protective coatings and industrial products) as it happened, for example, with external architectural polychromies where the need to identify alternative treatments for conserving exterior surfaces that have retained a reasonable amount of historical material is of the outmost importance. Consequently further scientific research on traditional materials, techniques and skills would be desirable and could continue to improve the results in the future. In this regard collaborative studies on the subject of far east Asian architectural polychromy at the international level should be encouraged and implemented
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Characterization of outdoor bronze monument patinas: the potentialities of near-infrared spectroscopic analysis
No full textThe corrosion products usually found on outdoor bronzes are generated by the interaction between the metal alloy and the atmospheric pollutants. To protect the external surface of bronzes, different organic materials (natural or synthetic) can be applied, creating over time a patina consisting of a complex mixture of inorganic and organic degraded components. The correct chemical characterization of patina constituents is fundamental to define the state of conservation of a metal artwork and address proper restoration actions. In this paper, we evaluated the potentialities of near-infrared (NIR) reflectance microscopy (4000–7500 cm−1) as complementary method to mid-infrared (MIR) analyses for the characterization of bronze patinas. Although NIR spectroscopy has been already used in the field of heritage science, its application for the characterization of bronze patinas is almost unexplored. In this paper, several corrosion products usually found on the surface of outdoor bronze sculptures were synthesized, characterized, and submitted to the NIR-MIR total reflection analysis to build up a reference spectral database. We devoted particular attention to the NIR features of copper hydroxychlorides, such as atacamite and paratacamite, which have not been studied in detail up to now. A selection of organic-based formulations, commonly used by restorers to protect the bronze surface against the outdoor aggressive environment, were also considered as references. Successively, NIR-MIR reflectance microscopy was successfully employed for the analysis of patina micro-samples collected from the bronze statues of the Neptune Fountain (sixteenth century) located in Bologna. The obtained results demonstrate the ability of NIR spectroscopy to identify organic and inorganic patina constituents, even in mixtures. In addition, the study can be considered as a proof of concept for the possible future application of the technique for in situ diagnostic campaigns on bronze sculptures
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