1,720,953 research outputs found
Influence of blended cements on rate of steel corrosion in reinforced concrete structures in a marine tidal zone
Full text linkThesis (Master: Engineering: Civil Engineering)--Central University of TechnologyTo minimise the impact of early deterioration of reinforced concrete (RC) structures in the marine environment, blended cements made using supplementary cementitious materials (SCMs) are used. However, the physical, chemical, and mineralogical composition of these materials varies, hence, there is variation in their performance. This study therefore investigated the influence of selected SCMs on the corrosion rate of RC structures in a marine tidal zone, in correlation with some influencing parameters of reinforcement corrosion such as cover depth, oxygen availability, and concrete resistivity. This was achieved through an automated cycle change system, simulating the natural tide change in the marine tidal zone. Accordingly, three binders (100%PC, 70%PC/30%FA, and 50%PC/50%SL), 2 water to binder ratios (w/b) (0.45 and 0.65), and 2 cover depths (20 mm and 40 mm) were used to manufacture corrosion specimens. A total of 12 specimens were cast, each reinforced with one high tensile mild steel to act as an anode and 2 stainless steels (316 grade) which served the function of cathode. The corrosion specimens were exposed to a simulated marine tidal zone in the laboratory, which consisted of 6 hours of cyclic wetting with 5% NaCl solution and 6 hours of air-drying for a period of 3 months. All corrosion specimens were connected to a data logger which measured the voltage across a 100-ohm resistor between the working and counter electrodes on a weekly basis. The resulting current was calculated as the corrosion rate indicator. The results of this experimental study indicate that, at the early age of RC structures in the marine tidal zone, the rate of reinforcement corrosion is mostly influenced by the concrete quality and concrete cover depth. The increase in concrete cover depth reduced the corrosion rate of all the specimens, irrespective of the w/b. This was because of the increased travel path for chlorides and oxygen. In addition, higher cover depth prolongs the drying rate of the concrete pore structure, causing low oxygen availability, especially at low w/b, and thus low corrosion risk. Furthermore, a higher w/b 0.65 was found to increase the corrosion risk of the specimens, especially at lower cover depth. Nevertheless, due to the denser microstructure of blended cement concretes, Portland cement (PC) exhibited the highest corrosion rate. Hence, it can be inferred that high w/b can be used in the application of blended cements, provided relatively higher cover depth is used. Blended cement concretes, overall, showed relatively high concrete resistivity compared to PC concretes. In relation to the refinement of the exposure classification used in SANS guidelines, the findings of this study support the notion of adopting the classification of RC structures with a concrete cover depth ≥ 30 mm in the same category as the submerged zone. However, a further laboratory investigation over a longer period of exposure is required to further clarify the corrosion performance of blended cement concretes in a marine tidal zone
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
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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