1,720,955 research outputs found
Thermal stress evaluation and safety aspects associated with massive concrete constructions joined to existing structures: The case of a masonry gravity dam
No full textThis study has been carried out with the aim to investigate, by means of the Finite Element analysis, thermal stresses induced by hydration heat generated during the construction phase of a massive concrete structure. An useful numerical tool has been developed in order to analyze the construction process of a concrete wall three-five meters tick built in contact with the upstream face of an old masonry gravity dam. This structural modification is needed to augment the height of the dam crowning and improve structural safety of the barrage during the new operational conditions of the reservoir characterized by an increase of the maximum water level and seasonal storage. The wall is built with layers about three meters height: during their placement, as a combination of initial high heat generation, long dissipation path and small thermal conductivity of the concrete, the inner temperature of the wall rise to values considerably greater than the one into the masonry, thus generating high gradients normal to the wall-dam interface. Furthermore during the hydration process the elastic modulus of concrete rises significantly producing an increase of the internal constraints. Being the two structures fixed each other, they becomes coupled for both thermal and elastic events: differential dilatation and constrained deformations induce tensions of traction that, when exceed the tensile stress, induce a cracking system. Beside deteriorating mechanical properties of the materials, this would cause water penetration from the reservoir during the exercise conditions and following pore pressure which worsen the static condition of the structure. Correct evaluation of the elastic internal stresses due to described phenomena requires to perform a sequential transient non-linear analysis providing time-spatial evolution of the temperature field due to the hydration heat and stresses induced by thermal stains. Preliminary studies have been carried out by means of a one dimensional model including the main features of the problem in order to test the Finite Element code capabilities and the influence of parameters
The heightening of an old masonry gravity dam
No full textThis paper illustrates the principal aspects of the study for the heightening intervention of a masonry gravity dam built in 1930. So far the dam has been utilized as flood control reservoir with normally empty basin; now a functional modification is needed in order to employ the structure for both control floods and water supply. Heightening of the maximum water level is thus requested. The suggested solution consists of a concrete wall close to the upstream face. The new structure becomes complex [1] and the study of the coupling between the wall and the dam requires the adoption of the Finite Element Method, carrying out both mechanical and hydraulic models including portion of the foundation rock
Heightening of an old masonry gravity dam
No full textThis paper illustrates the principal aspects of the study for the heightening intervention of a masonry gravity dam built in 1930. So far the dam has been utilized as flood control reservoir with normally empty basin; now a functional modification is needed in order to employ the structure for both control floods and water supply. Heightening of the maximum water level is thus requested. The suggested solution consists of a concrete wall close to the upstream face. The new structure becomes complex [1] and the study of the coupling between the wall and the dam requires the adoption of the Finite Element Method, carrying out both mechanical and hydraulic models including portion of the foundation rock. © 2005 Civil-Comp Press
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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