1,721,195 research outputs found
Introduction and Background
No full textThe absence of a standardised methodology to evaluate creep in the cracked state of fibre-reinforced concrete (FRC) hindered general comparisons and conclusions that could lead to significant advances in this topic. A coordinated effort was required to improve the knowledge on long-term behaviour of cracked FRC sections and assess the different testing methodologies available. The RILEM Technical Committee 261-CCF launched in 2015 the round-robin test (RRT) on creep behaviour in cracked sections of FRC program. This chapter includes the introduction and background to understand the realisation of this RRT. The main objectives as well as the limitations of the scope of the RRT are explained. The structure of the book is presented to provide a first overview of the book content. Finally, information about institutions involved as well as geographic distribution of RRT participants and number of specimens tested in the RRT is provided.Fil: Llano Torre, Aitor. Universidad Politécnica de Valencia; EspañaFil: Serna, Pedro. Universidad Politécnica de Valencia; EspañaFil: Cavalaro, Sergio H. P.. University of Loughborough; Reino UnidoFil: Buratti, Nicola. Universidad de Bologna; ItaliaFil: Stefan Bernard, E.. Technologies in Structural Engineering; AustraliaFil: Boshoff, William P.. University of Pretoria; SudáfricaFil: Zerbino, Raul Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; ArgentinaFil: Pauwels, Hans. Bekaert S.A.; BélgicaFil: Kusterle, Wolfgang. Universitat Regensburg; AlemaniaFil: Garcia Taengua, Emilio. University of Leeds; Reino UnidoFil: Vrijdaghs, Rutger. Katholikie Universiteit Leuven; BélgicaFil: del Prete, Clementina. Universidad de Bologna; ItaliaFil: Santos, Karyne F. dos. Universidade do Brasília; BrasilFil: Parmentier, Benoît. Belgium Building Research Institute; BélgicaFil: Mazzotti, Claudio. Universidad de Bologna; Itali
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
Self healing capability of concrete containing crystalline admixtures in different exposure conditions
No full textSelf-healing materials have the capability of recovering their performance after damage has occurred. In this work, the self-healing effect of a crystalline admixture for concrete is analysed in different environmental exposures. In order to compare healing capacity of the admixture compared with autogenous healing of concrete, two types of concrete were studied: a control concrete (CC) and a mix containing the crystalline admixture (CAC), with a dosage of 4% by the weight of cement. Four exposure conditions were studied: water immersion, water contact with a water layer of two centimetres, humidity chamber and laboratory conditions. Self-sealing/healing was studied by analysing the permeability of the cracked specimens and by observing with a microscope the closing of the crack. As from the obtained results CAC showed better healing behaviour than CC; the healing rates of CC had higher dispersion than those of CAC, which achieved more stable behaviour for all the different exposures and was anyway able to provide some not negligible healing capacity also in open air conditions. Differences between the exposures with direct contact with water were also noticed, indicating the importance of water for the reaction to take place
Study of the self-healing behaviour of early age cracks in concrete with crystalline admixtures under six environmental exposures
No full textThe search for self-healing materials is justified by the increasing sustainability and safety needs of structures. The presence of small cracks in structural concrete, which could accelerate the degradation process and diminish its service life, is unavoidable due to the heterogeneous nature of the material. A method to enhance self-healing in concrete is the use of crystalline admixtures (CA), which are hydrophilic products formed by chemical active substances, cement and sand.
This research analyzes the self-healing properties of young concrete specimens for autogenous and CA-based healing under different exposure conditions. Two types of concrete were studied: a control mix, and a mix containing the CA (with a dosage of 4% by the weight of cement). Six exposure conditions were studied: water immersion at 15oC, water immersion at 30oC, water contact with a water head of 2 centimeters, wet/dry cycles, humidity chamber, and laboratory conditions.
Self-healing capability was evaluated by measuring the permeability of concrete specimens before and after the healing period. Cylindrical specimens were pre-cracked by means of splitting test at the age of 2 days, and their permeability measured at the age of 3 days and after 42 days in the healing exposure. The range of studied crack widths was limited to 300 micrometers.
From the tests, the self-healing reaction was confirmed for both mixtures for exposures in direct contact with water. Exposing just one surface to water contact increased healing rates, but only the crack in direct contact could be sealed. Finally, slight differences were measured between both mixtures, with a higher stability for concrete with CA.
To sum up, only cracks in direct contact with water could heal, achieving higher healing rates when the specimens were immersed in water. Ambient humidity was not enough to produce healing either for control concrete or concrete with CA
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
La ley hipotecaria : comentada y concordada con la legislación anterior española y extranjera, precedida de una introducción histórica y seguida de un diccionario y formularios...
Full text linkDispelling 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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