1,720,952 research outputs found
Structural Behaviour of Slender Geopolymer Concrete BeamsWithout Stirrups
No full textGeopolymer concrete is a new alternative material to conventional concrete with less carbon dioxide emissions. Researchers have reported much research on the material properties of geopolymer concrete. However, research on the behaviour of this newmaterial at the structural level is still limited, especially at a full-scale structural level. Three geopolymer concrete beams with a total height of 700mm were tested till the shear failure. The first two specimens were subjected to the monotonically increasing load until the shear failure. The third specimen was first loaded under sustained load at the level of 80 kN for three weeks to investigate the influence of shrinkage and creep on the cracking behaviour. Then the specimen was then unloaded and reloaded again to failure. Digital Image Correlation (DIC) measurement was used to measure the surface deformation of the whole span of the beam. The crack spacing, crack width and crack development were investigated using the DIC measurement. The experimental results showed that the shear capacity of tested geopolymer concrete beams is lower than the calculated result based on the Eurocode.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Concrete Structure
Application of Coda Wave Interferometry with embedded Smart Aggregate in a prestressed cast-in-situ concrete continuous slab bridge
No full textIn recent years, the area of structural engineering has found new interesting prospects in the theory of waves. The acoustoelastic properties of materials are utilized in a new promising structural health monitoring (SHM) technique. The propagation of ultrasonic waves through stressed elements gives the ability to find invaluable information on the stress-state of the concerned element. This information is then analyzed with the use of Coda Wave Interferometry (CWI). This technique explores the late arrivals of the wave field, which is referred to as the coda. Due to scattering of the waves through heterogeneous elements, this part of the wave field holds additional information compared to the early arrivals, which makes it very suitable for application on concrete elements.The use of ultrasonic waves with CWI in concrete elements has been studied enthusiastically by engineers due to its promising prospects. Nevertheless, this technique is still developing both in theory and in practice. The majority of previous similar studies have been conducted in laboratory settings, and thus conditions are very controlled. In this study, the monitoring technique is applied in conjunction with Smart Aggregate (SA) to a concrete structure for practical use. The SA sensors are positioned in groups at key location in the first concrete cast of a cast-in-situ prestressed concrete bridge, which entails two bridge spans of approximately 30 meters length. Measurements are done at different phases during the construction of the bridge, when the stress-state at the positions shifts due to change in loading and boundary conditions. The resulting data is analyzed with CWI and subsequently evaluated whether it coincides with expectations. Deviations from these expectations are rationalized or an attempt thereof is made.The results show significant differences between field measurement results and expectations based on laboratory tests. These differences are explained by the presence of a greater amount of parameters, which influence the data gathered from field measurements. With the appropriate measures, the various factors acting on the structure are isolated and subsequently validated with laboratory data. The most prominent factors affecting the acoustoelastic properties of the structure are established to be time related. These factors involve concrete shrinkage, creep deformation and the concrete hydration process. With laboratory testing the effect of these factors on the wave propagation velocity are determined. By taking into account the additional factors, a strong correlation between changes in the stress-state and changes in the wave propagation velocity is observed when the data is read in an adjusted manner.With a proper protocol, the use of smart aggregates in combination with CWI could be very valuable in accessing concrete structures on-site in both its construction stage and service stage. As it stands, prerequisite knowledge of the monitored structure is necessary to make use of the full potential of the SHM involving CWI and SA. The demand for prerequisite knowledge of the structure increases as the monitored structure becomes more complex, because it increases the amount of additional endeavors required to properly asses the acquired data. As such, the discussed monitoring technique in its current stage of development generally has low accessibility for practical use. But with further research and more understanding of monitoring method, the discussed SHM technique might be applicable for general use in the near future.Civil Engineering | Structural Engineering | Concrete Structure
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
Trans-eQTLs Reveal That Independent Genetic Variants Associated with a Complex Phenotype Converge on Intermediate Genes, with a Major Role for the HLA
Get PDFThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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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