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Replacement of cement with waste ceramic powder in cementitious composites: results of a preliminary investigation
No full textRecycling ceramic waste powder: effects its grain-size distribution on fresh and hardened properties of cement pastes/mortars formulated from SCC mixes
No full textThis article presents the results of a preliminary study assessing the feasibility of using waste ceramic powder as a partial replacement of cement and/or sand in cement pastes and mortars. Two different ceramic powders, featuring different grain-size distributions, have been employed, one from crushed bathroom fixtures and dental prosthesis waste and a second one from foundry industry residuals. With reference to cement pastes and mortars formulated from SCC mixes employed in precast industry, cement replacement volume percentages equal to 10 and 30% have been considered for each powder. The possibility of hybrid cement and sand replacement with either powder has also been addressed. Effects of the replacement on the workability, shrinkage, compressive and flexural strengths have been considered, up to 3 months curing. The results confirmed the possibility of using this kind of waste in concrete, thus reducing the demand for raw cement and the burden on disposal landfills
Verso elementi in calcestruzzo armato precompresso senza acciaio: uno studio sperimentale
Get PDFI materiali compositi sono i principali attori nella sfida verso la ricerca di alternative sostenibili e durevoli all’acciaio per il rinforzo di elementi strutturali in calcestruzzo armato. Tra di essi, le barre costituite da fibre di basalto annegate in matrice polimerica rappresentano un’interessante novità, visto il loro basso costo di produzione, sia ambientale sia economico, e le loro proprietà meccaniche e di resistenza alla corrosione. In questo lavoro vengono presentati i risultati di una campagna di studio, svolta nell’ambito di un più ampio progetto di ricerca europeo denominato EiroCrete, che ha visto la collaborazione del Politecnico di Milano e della Queen’s University of Belfast con aziende italiane (Azichem srl) ed irlandesi (Banager Precast ltd.), e finalizzata a verificare la possibilità di utilizzare tali barre per la precompressione di elementi in prefabbricati in calcestruzzo armato precompresso, realizzati in calcestruzzo autocompattante rinforzato con fibre polimeriche
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Effect of waste ceramic powder on strength development of cement based mortars
No full textThis study presents the results of a preliminary study aiming at assessing the feasibility of using waste ceramic powder as a partial replacement of cement in cement based mortars. The aim is to improve the sustainability footprint of concrete and cement based construction materials in the precast industry. Two different ceramic powders have been employed, one from crushed bathroom fixtures and dental prosthesis waste and a second one from foundry industry residuals. Two different cement replacement volume percentages have been considered for each powder type, equal to 10% and 30%. Effects of the replacement on the workability, shrinkage behaviour and on the compressive and flexural strength have been considered, up to curing periods as long as three months. This is aimed at establishing if there is any potential for pozzolanic activity. The study is prodromal to investigating durability characteristics, including exposure to severe environmental conditions. The results of the study provide an interesting insight into the possibility of using this kind of wastes as a concrete constituent, thus reducing the demand for raw cement and the burden on the landfills for disposing of such kind of invading waste
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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