1,720,970 research outputs found
Experimental characterization of strain rate effects and impact behaviour of phenolic sandwich structures
No full textPerformance of FRP tendon-anchor systems for prestressed concrete structures
No full textConsiderable research has already been conducted on the mechanical response of fiber reinforced plastic (FRP) tendons for use in pretensioning and post-tensioning concrete structures. Th is research has been performed primarily outside of the United States and directly by tendon manufacturers. An experimental investigation was undertaken to provide a domestic evaluation of the mechanical performance of ten different aramid, glass, and carbon FRP tendons, with attention paid to the effects of the anchorage device recommended by the manufacturer The first phase of the project herein reported consisted of the verification of some tendon-specific properties, namely: ultimate strength, modulus of elasticity, and ultimate strain. If was determined that, given the limitation of the experimental program, a reasonable correlation exists with data supplied by manufacturers. In most cases, the anchorage devices permitted the tensioning to failure of the FRP tendons. Ultimate load capacity was generally controlled by the anchor rather than the tendon itself, suggesting that anchor efficiency could be improved. If was determined that heating one anchor to 60 degrees C (140 degrees F) had no detrimental effect on the tensile performance of the tendon-anchor system
Transfer and development lengths of FRP prestressing tendons
No full textAn experimental investigation was conducted to determine the transfer length, development length and flexural behavior of fiber reinforced polymer (FRP) tendons in prestressed concrete beams. Three types of tendons were included in the study: carbon leadline, aramid technora, and a carbon fiber reference material. In addition, 12 control beams were pretensioned with a 7 wire steel strand (ST). The transfer length for FRP tendons was reasonably well predicted by the ACI design equation, with the modification in AASHTO providing for a minimum transfer length. The ACI equation predicts the development length conservatively provided the tendon stress at nominal capacity. The article proposes the modification of the ACI equation to account for the larger bond stress developed by the FRP tendons
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
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
Behavior of FRP strengthened reinforced concrete beams under torsion
No full textThe use of fiber reinforced plastics (FRPs) for flexural and shear strengthening of reinforced concrete beams has been scrutinized to a considerable depth by researchers worldwide. The area of torsional strengthening however has not been as popular. This paper presents the results of an experimental investigation together with a numerical study on reinforced concrete beams subjected to torsion that are strengthened with FRP wraps in a variety of configurations. In the experimental study, the increase in the ultimate torque for different strengthening configurations, failure mechanisms, crack patterns, and ductility levels are monitored and presented. Experimental results show that FRP wraps can increase the ultimate torque of fully wrapped beams considerably in addition to enhancing the ductility. The experimental results upgrade the weak archival data on torsional strengthening by application of FRP. The numerical section reports on analyses performed by the ANSYS finite element program. Predictions are compared with experimental findings and are in reasonable agreement
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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