1,720,965 research outputs found
Factors influencing charge capacity of vanadium pentoxide thin film during lithium ion intercalation/deintercalation cycles
No full textXPS study of the Li intercalation process in sol-gel-produced V2O5 thin film: influence of substrate and film synthesis modification
No full textOxyfuel combustion residues as supplementary cementitious materials for the production of blended Portland cements
No full textOxyfuel combustion represents one of the most interesting processes aimed at CO2 capture and storage to mitigate greenhouse effects ascribable to the process industry. In a different technical area, searching for new processes aimed at producing low-CO2 cements has comparable relevance, due to the huge generation of greenhouse gases related to cement production. This paper proposes an integration of these two aspects, with an approach new in the pertinent literature. The possibility of reusing ashes, issued by a pilot plant fluidized bed oxyfuel combustion process, as a source of material in the production of low-CO2 cements is investigated. Ashes were tested as substitutes for natural pozzolan in blended cements. They were mixed with an industrial Portland clinker and natural gypsum in order to evaluate their hydraulic behavior at different curing temperatures (20–40°C) and times (2–28 days). Pozzolanicity tests together with differential thermal–thermogravimetric and X-ray diffraction analyses were employed to explore the hydration behavior of oxyfuel ashes-based blended cements
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
Use of Fluidized Bed Combustion Residues and Alumina Powder as Components of Ettringite-Based Aerated Building Elements
No full textThe use of industrial wastes and by-products for making construction materials unequivocally gives a
pronounced environment-friendly character to their manufacturing process. Two binary (M1, M2) and one
ternary (M3) mixtures, based on alumina powder, fluidized bed coal combustion fly- and/or bottom-ash were
submitted to hydrothermal treatments in order to generate aerated building elements based on ettringite
(6CaO·Al2O3·3SO3·32H2O); ettringite is a compound characterized by low density, water insolubility, high fire
resistance and significant mechanical strength. The M1 – M3 systems were hydrated in a thermostatic bath
(100 % R.H) at 55 °C and 70 °C for aging periods ranging from 2 h to 28 d; the hydrated samples were
submitted to both differential thermal–thermogravimetric and X-ray diffraction analyses for assessing the
formation of the hydration products. In this regard, the ettringite generation, being also dependent on the
operating temperatures and times, was observed within all the investigated systems. Furthermore, the best
results in terms of both ettringite concentration and formation rate were exhibited by the M2 system at 70 °C
after 2 d of curing
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
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