1,720,965 research outputs found
The mechanism controlling corrosion of steel in carbonated cementitious materials in wetting and drying exposure
No full textExperiments were performed to study the mechanism of corrosion of steel in carbonated concrete in cyclic wetting/drying exposure. It was found that the corrosion rate increased during wetting, followed by a decrease during drying. The increase and decrease of the corrosion rate can be explained by changes in electrochemically active steel area as a function of the moisture state of the mortar and its porosity. The corrosion rate achieved in the wet phase stabilizes during the first few wetting and drying cycles. The mechanism of the electrochemical process is discussed on the basis of theoretical considerations. It is concluded that the corrosion kinetics are under activation control. The availability of oxygen does not seem to be a limiting parameter for the corrosion process in cyclic wetting/drying exposure
Innovative sample design for corrosion rate measurements in carbonated blended concrete
No full textLowering the clinker content of concrete using SCMs can contribute significantly to reduce the energy consumption for cement production and the CO2 emissions of building materials. Substitution of clinker up to 65% is now possible according to European and Swiss standards. Uncertainty about durability, especially carbonation induced corrosion, is the main factor limiting the practical use of these blended cements. For service life prediction of concrete structures with new, blended cements corrosion rate data are urgently needed because the so called “corrosion propagation stage” might be a significant part of the total service life. Such data so far can be obtained only with very time consuming tests due to the sample size of standard concrete samples and the slow carbonation process. In this paper an innovative experimental setup is presented that overcomes these limitations. The setup consists in miniaturised thin samples with a size of 80 x 80 x 6 mm, thus with an effective carbonation depth of only 3 mm. With this new sample design the corrosion rate of steel in carbonated samples can be studied at any relative humidity. Our preliminary results show that these samples allow any kind of electrochemical measurements can be performed – thus the study of corrosion and related influencing parameters, in homogenous carbonated conditions, is possible within a short time scale
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
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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