1,720,976 research outputs found
Effect of mixed micelles on relative counterion binding constants and counterion-induced micellar growth / Fagge Ibrahim Isah
Full text linkSemi empirical kinetic technique has been used to determine the values of both cationic CTABr (hexadecyltrimethylammonium bromide) and mixed cationic-nonionic CTABr-C16E20 (hexadecyltrimethylammonium bromide-polyethoxy hexadecyl ether) micellar relative binding constants (KX/KBr and mKX/mKBr) of counterions, X and Br, (= KXBror RXBr and mKXBr or mRXBr), where superscript “m” signifies mixed micellar system, for X = 2-NaOC6H4CO2, 3,5-Cl2C6H3CO2 and 4-ClC6H4CO2 and correlate them to their specific rheological observations. The kinetic investigations on the influence of CTABr-C16E20 on the values of KXBror RXBr in aqueous solutions of 2-NaOC6H4CO2Na and NaBr has been carried out. The presence of 0.006 M C16E20 decreases the mean values of KXBr or RXBr from 42 to 16 (2.6-fold lower). Rheological measurements of 0.015 M CTABr/2-NaOC6H4CO2Na/H2O solutions at 25 and 35 C revealed a single maximum for [2-NaOC6H4CO2Na] = 0.02 M as the zero shear viscosity (o) was plotted against [2-NaOC6H4CO2Na]. This shows, indirectly, that the is a possibility of the presence of wormlike micelles whereas the possible existence of spherical micelles was revealed at [C16E20] 0.006 M. A similar study, with a different counterion, 3,5-Cl2C6H3CO2 has also been reported. The average value of KXBr or RXBr, for CTABr/3,5-Cl2C6H3CO2Na/H2O solution (KXBr or RXBr = 198) appeared to be almost 2½-fold larger than that of CTABr/3,5-Cl2C6H3CO2Na/C16E20/H2O (mKXBr or mRXBr = 78). Rheometric results of 0.015 M CTABr/3,5-Cl2C6H3CO2Na/H2O solution at 25 and 35 C indicate that the plot of zero shear viscosity (o) against [3,5-Cl2C6H3CO2Na] has two maxima at two different concentrations of 3,5-Cl2C6H3CO2Na (0.015 and 0.04 M) and this also shows the possible existence of wormlike micelles. Contrarily, a possible formation of spherical micelles for CTABr/3,5-Cl2C6H3CO2Na/C16E20/H2O solution ([CTABr]T = 0.015 M and [C16E20]T = 0.006 M) was observed at the same temperatures. The effects of CTABr-C16E20 on 4-ClC6H4CO2 has also been investigated. The respective mean values of KXBr or RXBr obtained for CTABr/4-ClC6H4CO2Na/H2O solution (KXBr or RXBr = 50) is 2.3-fold larger than that of CTABr/4-ClC6H4CO2Na/C16E20/H2O (mKXBr or mRXBr = 22). The possible existence of wormlike micelles was also observed from the rheometric data of 0.015 M CTABr/4-ClC6H4CO2Na/H2O solution based on the plot of o against [4-ClC6H4CO2Na]. The observation also revealed the presence of a single maximum at [4-ClC6H4CO2Na] = 0.03 M where it was thought that spherical micelles were formed in CTABr/4-ClC6H4CO2Na/C16E20H2O with 0.015 M CTABr and 0.006 M C16E20. The quantitative correlation between the magnitudes of relative counterion (X) binding constant (KXBror RXBr and mKXBr or mRXBr) and X-induced cationic micellar structural growth have been reported for the first time in this thesis. The highlight on the possible cause was that adding nonionic surfactant to an aqueous solution of cationic micelle-forming surfactant could be a technique to achieving changes in the structural, as well as the viscoelastic behavior of cationic micelles in the presence of certain inert organic salts
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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