1,720,953 research outputs found
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
Condition Monitoring of Transformer Oil and Paper
No full textPh.D. Thesis, January 2005.
Supervised by Dr. Maheshwar Roy (Thapar Centre for Industrial Research & Development, Patiala, Dr. Amitabh Verma, General Electric, Bangalore and Dr. Vimal Bhanot, Birla Institute of Technology & Science, PilaniLike other machines, transformer too has limited life. However, unlike other machines, it does not have any moving parts, except tap changers or cooling fan or pump motors. The outages, therefore, is not due to wear out.
The transformers die because of deterioration of insulation over time. Generally, cellulosic paper and mineral oil form bulk of insulation in the transformer. The insulation is subjected to a variety of stresses, such as thermal, mechanical, electromagnetic, etc. Under the influence of the said stresses and in the presence of oxygen and moisture, the insulation deteriorates continuously over a period of time, eventually leading to failure. If these failures can be predicted with some degree of confidence, sudden failures can be minimized.
In view of the above, efforts are being made to understand and analyze factors responsible for determining the life of a transformer. Broadly, ageing of insulating material can be looked upon as a chemical reaction, which takes place at a rate that is influenced by thermal, electrical and mechanical stresses. All chemical reactions lead to product(s), which have physical and chemical characteristics different from the parent material. Therefore, chemical and physical characterization of the reaction product(s) may assist in monitoring the health of the insulation and hence transformer. For instance, cellulose undergoes degradation under thermal stress: the Degree of Polymerization (DP) of cellulose is reduced due to thermal ageing. Besides, it leads to the formation of reaction products, such as carbon monoxide, carbon dioxide, water, furan, etc. Furans are a family of organic compounds like 2-furfuraldehyde, 2–acetylfuran, 5-methyl-2- furfuraldehyde, furfurylalcohol, 5-hydroxymethyl -2- furfuraldehyde, etc. It is therefore, possible to estimate the extent of insulation damage by monitoring reaction product(s).
Moreover, these changes in cellulose, at molecular level manifest in change of physical properties. Tensile strength, dielectric breakdown voltage, tan-ä of Kraft paper are the physical properties affected by these changes. For example, breakage of cellulose chain at microscopic level may lead to microscopic voids, which may influence the partial discharge behaviour of the material.
Over the years a number of studies, involving monitoring of one or more of above parameters, have been carried out to predict the impending death of transformer. However, the results are far from complete. Laboratory studies have been carried out to study ageing behaviour of cellulose paper and oil. Mostly the studies are confined to thermal ageing and thus do not simulate the real life situation. Alongside the aging studies, efforts have been directed to develop sensors and instrumentation for on-line monitoring of some of the mentioned properties. But, a holistic approach to the problem is somehow missing.
In the present study an accelerated aging study involving combined application of thermal and electrical stress is carried out on cellulosic paper and mineral oil. All possible properties, which are likely to be affected by degradation i.e. such as Viscosity, Moisture, Breakdown voltage, Tan-delta, Dielectric Constant, Interfacial tension, Resistivity, Acidity and Flash point of oil and paper properties like Tensile Strength, Degree of Polymerization (DP), etc. are periodically measured. A few properties, which are related to the degradation of both paper and oil, like Partial Discharge (PD) and Dissolved Gas Analysis (DGA), have also been studied. In some cases a few reaction products are formed due to combined stresses like, different gases (CO2, H2, C2H2, C2H4, C2H6, CH4) and furanic derivatives which are dissolved in oil. The analysis of these reaction products have provided very useful information about the paper insulation system.
The dissolved gas analysis (DGA) is carried out on the aged samples to predict the incipient faults. Though there is no direct method to detect these incipient faults, it is known that these faults, especially in the form of overheating, arcing or partial discharge, develop certain gaseous hydrocarbons, that are retained by the insulating oil as dissolved gases. Thus the evaluation of these gas compositions and their interpretation, known as Dissolved Gas Analysis (DGA), seems to be one of the life saving diagnostic tests on condition monitoring of transformers.
A wide range of techniques is available for pattern recognition of PD signatures. The first significant system developed for analyses of PD signatures, as observed on an oscilloscope, was published by CIGRE in 1969. In the late 1980s computerized data acquisition became commonly available, facilitating acquisition, storage and digital processing of discharge patterns. Earlier the integrity and quality of insulation was checked by various tests like power frequency voltage withstand test, loss angle measurement, insulation resistance measurement, impulse voltage withstand test etc. But with above measurements, the minor insulation flows and improper/inefficient processing of insulation was not identified. Many cases were found where the material having a very high insulation resistance failed within an unexpected short duration. Many experiments were carried out to understand the phenomena and after various experiments and research on the progressive deterioration of the insulation, it was found that such a failure is only due to the phenomena named Partial Discharge. If there is an air gap or void in the solid insulation, the localized electrical discharge in the insulating media, which are restricted to a small part of the dielectric under test partially, bridges the insulation between the electrodes. Because of this, progressively large leakage current path develops in the insulation and results in an ultimate failure of the object. The early detection of partial discharge present in a transformer is very important to avoid/reduce the losses to the catastrophic failure of transformer. Also, once the PD is detected, the location of the same is very important so that the defects can be pinpointed and solved effectively. The furanic compounds analysis reveals the rate of insulating paper degradation of the equipment and it directly projects the expected life. As this degradation is not observable by any other means, it is one of the essential tests to diagnose the equipment.
Cellulose insulation has a structure of long chains of molecules. The cellulosic paper contains about 90% cellulose, 6-7% of hemi-cellulose and 3-4 % of lignin. Cellulose is a natural polymer of glucose and it degrades slowly as the polymer chains breakdown during service, releasing degradation products into the oil. The paper eventually degrades to such an extent that it loses all its mechanical strength and becomes susceptible to mechanical damage, which puts the electrical integrity of the equipment at risk. Efforts have been made to identify the most sensitive properties with respect to ageing and to establish a correlation between various properties. Eventually, this knowledge data base will help in evolving a condition monitoring strategy and instrumentation for actual transformers.
In this thesis work, the accelerated thermal and electrical stress has been applied to predict the life of the liquid and solid insulation. Under these stress conditions, the physicochemical properties of oil like viscosity, moisture, breakdown voltage, resistivity, loss angle, dielectric constant, acidity, flash point have been observed. On the soil insulation i.e. kraft paper, wer have characterize the properties like tensile strength, degree of polymerization, furfural analysis, partial discharge, SEM and XRD studies.Thapar Institute of Engineering & Technology, Department of Electrical and Instrumentatio
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
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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