1,720,999 research outputs found
Methodological challenges for the investigation of the dual role of biofilms on outdoor heritage
Full text linkBiofilm deterioration and biofilm protection should be considered as different aspects of the complex interactions between microbes and the surfaces of outdoor heritage (e.g. stones, bricks, mortar and plaster). Thus, it is urgent to verify and quantify to what extent the biofilm can protect from different weathering processes, to eventually
determine the advisability of biofilm removal from the heritage surfaces. On one hand, it is necessary to more
precisely describe the decaying processes caused by the microorganisms and to quantify the extent, severity, and
rate at which the microorganisms are causing the decay. On the other hand, it is necessary to define methodologies
to comprehensively study the bioprotection phenomena. So far, no decision-making tool is available to guide heritage professionals in deciding whether to remove or keep biofilms on heritage surfaces, and aesthetical
alteration and discoloration is often the only criterion considered. In this work the different available approaches for the study of the dual role of biofilms on outdoor heritage have been critically reviewed. The open challenges and questions are also summarised
Production, characterization, and protection of artificial patinas on copper
No full textCopper and its alloys have found extensive use in artistic and architectural fields not only because of their nota- ble resistance to corrosion but also due to the beauti- ful colours of the patina of corrosion products that are formed when they are exposed outdoors. Green roofs and façades are highly appreciated by designers and citizens. In the past, in urban environments, such green patinas could be naturally formed because of the inter- action with pollutants, such as SOx, and are typically constituted by copper hydroxide sulphates such as bro- chantite and antlerite. SOx levels have been drastically reduced over the last decades and this means that we will not expect anymore the natural growth of green patinas on copper in urban environments (unless we are close to the sea, where the formation of chlorides-rich green patinas is expected). Depending on the location, artificially patinated surfaces may be nowadays a good solution to get green roofs. Artificial patinas may have quite different characteristics compared to natural ones and are often obtained by using polluting chemicals. It is therefore important to find low environmental impact procedures for their production and to obtain corrosion layers with characteristics very similar to the natural ones. In addition, it is important to understand if protec- tive coatings would maintain their efficacy when applied on patinated surfaces. This is particularly relevant in the field of cultural heritage conservation, where they are normally applied on corroded surfaces. Continuous re- search is dedicated to studying and developing protec- tive coatings, that act as barriers, preventing corrosion and simultaneously preserving the historic aspect of the surfaces. The coating also must ensure low toxicity and easy application to guarantee the safety of the restorer. In this study, a series of artificial patinas were produced and characterized. In addition, a multi-layer coating, widely used by restorers for the conservation of bron- zes, and a silane-based coating have been applied on artificially patinated surfaces
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
Corrosion inhibitors for the conservation of bronzes and gilded bronzes exposed to the atmosphere
No full textCorrosion inhibitors, associated or not with protective coatings, may be a good solution for planned conservation activities in case of bronze and gilded bronze works of art, such as the Doors of the Baptistery of Florence, the San Marco Horses in Venice or the Marcus Aurelius in Rome. The studies, in the cultural heritage area, have been mainly focused on the use of Benzotriazole, which is a good inhibitor, but it is toxic for people and environment. In this work, non-toxic corrosion inhibitors for bronze and gilded bronze are investigated. The inhibitors have been tested both on non patinated and patinated bronzes, reproducing renaissance leaded bronzes. The experimentation includes electrochemical measurements in artificial rain and 3.5% NaCl solution, short-circuit tests performed on gold/ bronze couples.
Materials and surfaces were characterised with and without inhibitive treatments
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
Anoxic treatment for the disinfestation of wood cultural heritage: assessment of the effects and harmfulness on different species
Full text linkWooden artefacts, wood painted panels and historic furniture represent a significant part of our cultural heritage. Their preservation over time is a challenging task, and insect infestation still represents a primary cause of loss of cultural heritage artefacts. Anoxic conditions have proved to be effective in pest control and have been extensively applied to the management of museum collections. The present work reports on the evaluation of the effects and harmfulness of nitrogen-based anoxic treatment on different wood species with or without superficial finishings. Specimens were prepared in order to be representative of various surfaces of cultural heritage objects. A complete monitoring of the treatment effects was performed by means of a multianalytical approach. FTIR spectroscopy in the MID-IR and NIR regions was conducted to assess the absence of chemical alterations, and the results were subjected to chemometric treatment by multivariate analysis. Colorimetric characterization of the surfaces was performed to monitor any undesired colour change induced by the conservation treatment. The absence of superficial mechanical damages was evaluated by means of optical and scanning electron microscopy. The results confirmed that the anoxic procedure is not harmful to the treated surfaces with respect to aesthetic, chemical and microstructural considerations, even when the most stressful conditions are applied. As wood permeability is an important parameter in order to plan an effective intervention, in this study, a simplified method to estimate the permeability of wood to oxygen in different conditions was tested
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