1,720,955 research outputs found
Establishing Fresh Properties of Fiber Reinforced Concrete for Performance Engineered Mixture (PEM)
No full textThe addition of macro or structural fibers into concrete enhances its post-cracking performance. The objective of this study was to conduct a laboratory investigation to determine the influence of structural fibers on the fresh concrete test parameters (Super air meter (SAM) number, V-Kelly index, and Box test rating) recommended for the performance engineered mixture (PEM) procedure. As many as fifty-seven different concrete mixes were designed and prepared, varying fiber types and dosages, aggregate types, and air contents of the concrete. Various fresh and hardened concrete tests were conducted on each of the mixes, and the results were used to determine the influence of the structural fibers on the fresh and hardened concrete properties. The study recommended the allowable range of the SAM number and provided necessary guidance on the box test rating and V-Kelly index for the fiber-reinforced concrete mixtures to be designed as per the PEM procedure.Barman, Manik; Kamara, Alieu; Janson, Austin. (2022). Establishing Fresh Properties of Fiber Reinforced Concrete for Performance Engineered Mixture (PEM). Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/241775
Fiber-Reinforced Concrete and Performance Engineered Concrete Mixture Design
No full textUniversity of Minnesota M.S. thesis. 2021. Major: Civil Engineering. Advisor: Manik Barman. 1 computer file (PDF); 135 pages.A challenging objective for the concrete industry, in using structural fibers in concrete pavements and overlays while moving towards the implementation of the Performance Engineered Mixture (PEM) design, is to understand the influence of fibers on tests performed in the PEM design procedure. The goal of the PEM design procedure is to produce concretes that resist climate and material related distresses, such as durability cracks and concrete-degradation due to chloride-ion penetration. The addition of fibers in a concrete mixture also increases concrete durability by enhancing post-cracking performance. Using PEM procedure for fiber reinforced concrete (FRC) pavements will produce durable concrete pavements that resist environmental- and material- driven distresses as well as possess an improved post-crack performance. The objective of this research is to study the relationship between different fresh concrete properties and their influence on the hardened concrete behavior and durability. The materials used in this study includes two types of coarse aggregates, fine aggregate, two types of fiber, cement, fly ash and admixtures. Two different fiber types (twisted and embossed geometries) and two fiber dosages (4 lb/ yd3 and 7.6 lb/ yd3) were considered in this study. Fresh and Hardened concrete test results for all the FRC mixes were compared to results of the control plain concrete mixes. Fresh concrete tests such as slump, air content, super air meter number (SAM), Box, and V-Kelly tests were conducted. Hardened concrete properties such as compressive strength, modulus of elasticity, beam flexural strength, resistance to distresses caused by multiple freeze-thaw cycles, and surface/electrical resistivity was determined. Based on the results of this study, it was found that fiber dosages and types significantly influence the V-Kelly index, while moderately influence SAM number and box test rating. The fibers used in this study had significant influence on the post-crack behavior of concrete. The freeze-thaw durability and surface resistivity test results indicated that fibers have less influence on the concrete resistance to freeze-thaw durability issues.Kamara, Alieu. (2021). Fiber-Reinforced Concrete and Performance Engineered Concrete Mixture Design. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/225091
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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