1,720,959 research outputs found
Ab Initio Study and Vibrational Spectroscopy of Imidazolium Based Ionic Liquids with Dissolved δ-MgCl2
No full textIonic liquids (ILs) are liquid salts at room temperature having unusual properties as liquids. The most important properties of these electrolyte solutions are non-volatility and high ion conductivity which makes them a safe and advance choice for electrolyte solutions in energy devices. In general, ILs as the name implies, are comprised entirely of ions, usually organic cations and bulky anions. ILs are stable enough for ordinary use at temperatures of 200 to 300 ̊C. However, due to having organic cations their degradation begins at the weakest covalent bond. The chemical structure of ions can be tailored easily for the intended application. The structure and properties of these Coulomb systems are mainly determined by the type and strength of the intermolecular interactions between anions and cations. In particular, the subtle balance between Coulomb forces, hydrogen bonds (HBs) and dispersion forces is of great importance for understanding ILs.
Having these superior properties, ILs can be used as a good carrier for ion transport in batteries. Recently, imidazolium based ILs with δ-MgCl ions have been under investigations as new electrolytes for Mg-based batteries. These batteries show advantages over other competing types owing to the abundant source of Mg in the earth’s crust, better disposal and waste management. In addition, they have wide operation temperature range and their capacity loss over time is little.
The aim of this work is to use the results of first principles electronic structure calculations to study the structure of the new imidazolium based ILs with dissolved δ-MgCl . Although, there have been many studies on the imidazolium based ILs, but there is still a debate on whether the hydrogen bonding is responsible for the red shifted C–H stretching frequencies and downfield shifted C–H proton chemical shifts or not. Therefore, further studies on the structure and interactions of imidazolium based ILs especially in presence of δ-(MgCl ) are essential and helpful in optimal design of this new genre of electrolytes.
Differential scanning calorimetry on electrolytes composed of different amount of δ-MgCl dissolved in a homogeneous mixture of aluminum tri-chloride and 1-ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid has been done. The results show that by varying δ-MgCl concentration at least two types of Mg complex depending on δ-MgCl concentration are formed. The IR spectrums show new peaks in the far infrared region by increasing the concentration of δ-MgCl indicating the formation of new bimetallic complexes. Also, Experimental IR investigations on EMImBF /[δ-(MgCl ) ] indicate that by increasing f which is the concentration of δ-(MgCl ), the Clˉ interaction band at 3050 cm , typical of the hydrogen bonding network in EMImCl appears in the difference spectra. The comparison between the profiles of pristine IL and EMImBF /[δ-(MgCl ) ] show that Mg forms different complexes with BF ˉ anion. However, these new complexes are not known.
Electronic structure calculations were undertaken on the ethyl-methyl imidazolium cation in proximity to a number of different anions (Clˉ, AlCl ˉ, BF ˉ) using Hatree-Fock (HF), post HF, DFT, and Hybrid methods with different basis sets. The calculations were performed using Gaussian 09 suite of program.
Geometry optimizations were followed by frequency calculations to confirm the presence of each local minimum. Different initial structures have been searched for each system to determine the global minimum. Then the calculated IR spectrums are compared to the experimental spectrums and the least expensive method which is capable of describing the experimental spectrum is chosen for further calculations. Next calculations are performed on larger clusters of cations and anions which contains MgCl . The IR spectrums are compared to experimental spectrums and the assignments of vibrational modes are done by visualizing the vibrational frequencies of the calculated structures
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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