1,720,984 research outputs found
Evaluating the self-sensing ability of cement mortars manufactured with graphene nanoplatelets, virgin or recycled carbon fibers through piezoresistivity tests
Get PDFThis paper presents the resistivity and piezoresistivity behavior of cement-based mortars manufactured with graphene nanoplatelet filler (GNP), virgin carbon fibers (VCF) and recycled carbon fibers (RCF). GNP was added at 4% of the cement weight, whereas two percentages of carbon fibers were chosen, namely 0.05% and 0.2% of the total volume. The combined effect of both filler and fibers was also investigated. Mortars were studied in terms of their mechanical properties (under flexure and compression) and electrical resistivity. Mortars with the lowest electrical resistivity values were also subjected to cyclic uniaxial compression to evaluate the variations in electrical resistivity as a function of strain. The results obtained show that mortars have piezoresistive behavior only if they are subjected to a prior drying process. In addition, dry specimens exhibit a high piezoresistivity only when loaded with 0.2 vol.% of VCF and 0.4 wt.% of GNP plus 0.2 vol.% RCF, with a quite reversible relation between their fractional change in resistivity (FCR) and compressive strain
Piezoresistive behavior of mortars loaded with graphene and carbon fibers for the development of self-sensing composites
No full textStructural monitoring systems are gaining increasing interest in the field of civil engineering research, due to the recent commitment for the preservation of building heritage, for the saving of resources and for an eco-friendly construction industry. Recent researches show that the addition of conductive fillers and fibers within cement materials could originate cement-composites able to diagnose their own state of strain and tension, measuring the variation of their electrical characteristics (resistance). In this work, resistivity and piezoresistivity of mortars complemented with Graphene Nanoplatelets (GNP), and Carbon Fibers (CF) were evaluated. The variations in electrical resistivity as a function of strain were analyzed under cyclic uniaxial compression of the mortars samples. The results showed a high piezoresistivity behavior of the mortars with an optimal dispersion of GNP and CF, with a quite reversible relation between Fractional Change in Resistivity (FCR) and compressive strain
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
Commercial and recycled carbon-based fillers and fibers for self-sensing cement-based composites: Comparison of mechanical strength, durability, and piezoresistive behavior
Get PDFThe possible use of industrial by-products as carbon-based fillers and/or fibers to produce Multifunctional Cement-based Composites (MCC) with piezoresistive behavior for Structural Health Monitoring (SHM) was investigated. As fillers, Used Foundry Sand (UFS) and Gasification Char (GCH) were compared with commercial Graphene Nanoplatelets (GNP). As fibers, 6 mm-long recycled carbon fibers (RCF) were compared with virgin ones. Mortars were tested in terms of mechanical strength, water absorption, microstructure, and piezoresistive behavior. UFS and GCH are more effective than GNP in decreasing the mortar electrical resistivity (−30%), total porosity (−11%), water absorption (−27%) and in increasing the compressive strength (+10%). The combination of UFS with RCF in mortars provides the best results in terms of fluidity, strength, water absorption, and piezoresistive parameters. Generally, a lower mortar resistivity, even if with lower piezoresistivity properties, allows the use of cheaper instrumentation for SHM, thanks to the lower full scale and the better correlation strength between the change in resistivity with strain
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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