1,721,042 research outputs found
Thermoluminescence (TL) characterization and dating feasibility of ancient glass mosaic
No full textTo achieve a better comprehension of the thermoluminescence (TL) properties and dating feasibility of mosaic glasses, a study on the connections between chemical composition and general TL behavior of glass tesserae has been carried out. Elemental analysis of the samples has been performed through electron microscopy with microprobe, inductively coupled plasma and X-ray fluorescence spectrometry. Preliminary results, relative to the study of the TL behavior of different groups of glass mosaic tesserae, classified by provenance and by chemical analyses, are reported and discussed. © 2000 Elsevier Science Ltd
Intermediate moisture traditional italian meat products: technological process transfer to llama meat curing
No full textGlass artefacts conservation: finding materials and methods for glass vessels’ reconstruction
Full text linkThis paper will address art glass conservation, focusing on the search for the best products and methods to be employed in glass vessels’ reconstruction, including case studies. In 2000, an archaeological site was found in Padua (Northern Italy) where the Santa Chiara in Cella Nova Monastery once stood (1325–1797), and thousands of Renaissance artefacts came to light. Thanks to a collaboration between the Soprintendenza Archeologia, Belle Arti e Paesaggio per l’Area Metropolitana di Venezia e le Province di Belluno, Padova e Treviso and the University of Bologna, a huge conservative project started. The conservative intervention on the precious glass vessels became the starting point of a research on the best products to be employed in their reconstruction. More than for other materials, an analytical approach is necessary while dealing with glass: commonly employed techniques need to be adapted to suit features of every object, and new ones must be examined. Furthermore, testing and comparing well known products to most recent ones or to ones developed for other purposes is essential. In this study, an acrylic resin and four epoxy resins were tested, the latter both pure and added with three different colouring agents. Accelerated ageing tests were run to find out the products most resistant to discolouration through time. The results were compared with practical application’s tests to select the best combination of products and techniques. Finally, the intervention on two glass vessels, coming from Santa Chiara Monastery, is presented briefly
Corrosion evaluation of artificially aged 6 wt-% tin bronze
No full textThis study concerns the corrosion behaviour of wrought 94 wt-%Cu-6 wt-%Sn (B6) bronze, whose composition is similar to materials used for outdoor bronze artefacts. In order to investigate the influence of the composition and microstructure on bronze corrosion processes, electrochemical ac and dc measurements in synthetic acid rain and chloride solutions were performed on the B6 binary alloy in comparison with an as cast bronze having a different degree of purity. Moreover, to perform thin layer activation (TLA) measurements of thickness loss, a suitable radio nuclide 65Zn (t1/2= 244 days) was produced on B6 specimens by a high energy proton beam. Artificial weathering experiments have been carried out by exposing activated and non-activated B6 specimens: To selected pollutants including NOx and SO2 at different concentrations to simulate urban and industrial atmospheres; in a cyclic salt spray cabinet to investigate the effects of marine environments; to basic (NH4)2SO4 solutions reproducing the aggressiveness of ammonia containing wet deposits. At the end of each test, the B6 corrosion rates obtained by weight loss determinations have been compared with those arising from the TLA method. Finally, the nature and microstructure of the surface oxidation products were investigated
Organic films for protection of copper and bronze against acid rain corrosion
No full textIn this paper, the anticorrosive effects of surface films formed on copper and bronzes by different organic inhibitors (mainly benzotriazole derivatives) are evaluated. Several alloys, nominally similar in composition to ancient artistic bronzes, were studied in comparison with copper. The protective efficiency of the organic coatings was tested by electrochemical ac and dc measurements performed both in acid and neutral rain. The experimental data show that benzotriazole derivatives with a long aliphatic chain form thin and very protective films on copper. The presence of the alloying elements (e.g. Sn, Zn, Pb) and multiphasic structures decrease the organic film performances. Nevertheless, among the compounds used, the most efficient, 5-octyl-1,2,3-benzotriazole (C8), seems to be a promising coating in the bronze conservation field. (C) 2003 Elsevier Ltd. All rights reserved
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
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
- …
