1,721,077 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
A comprehensive study of di diesel engine performance with vegetable oil: an alternative bio-fuel source of energy
No full textThis study offers comprehensive details on the use of bio-fuel as a viable and alternative source of energy. The bio-fuel was prepared from vegetable oil, i.e., mustard oil and tested in a diesel engine in both pure form and as a diesel blend. The mustard oil blend proportions were 20%, 30%, 40% and 50% and named as bio-diesel blends B20, B30, B40 and B50. A fuel-testing laboratory determined the properties of the pure mustard oil fuel and its blends, i.e., density, viscosity, dynamic viscosity, carbon residue, flash point, fire point and calorific value. An assessment of engine performance, i.e., brake horsepower (bhp), brake specific fuel consumption (bsfc), brake thermal efficiency (bte) and brake mean effective pressure (bmep) etc., was carried out for pure diesel, pure mustard and the blends, both in laboratory conditions and under British Standard (BS) conditions. Finally, an analysis and comparison was made of the effects of the various fuels on the different engine properties
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
Comparative study of diesel engine performance and emission with soybean and waste oil biodiesel fuels
No full textThe study investigated the engine performance and emission using biodiesel from soybean oil and waste cooking oil. The fuel properties of these biodiesels were determined using ASTM D6751and EN 14214 standards. The fuels were tested in a multi-cylinder diesel engine with an electromagnetic dynamometer and a 5-gas analyser was used for emission analysis. The result shows that the thermal performance of the engine slightly decreases with increase of the biodiesel blends ratio (i.e. B5, B10, B15, B20 and B50). On the other hand, emission decreases with the increase of biodiesel blends. The reduction in emissions was different for both biodiesels. Waste oil biodiesel showed better trends of emissions reduction with increase of the biodiesel percentage compared with soybean biodiesel. The brake specific fuel consumption (BSFC) of both biodiesels is (6.05%, 9.13%, 12.36% and 18.57% for soybean) and (8.17%, 11.40%, 17.71% and 14.96% for waste cooking oil) higher than diesel, respectively. However, soybean biodiesel consumed less fuel and produced more power and torque compared to waste oil biodiesel. The study concluded that B10 soybean biodiesel blend produced more consistent and expected results than waste oil biodiesel from the performance and emission point of view
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
Terahertz metamaterial with asymmetric transmission
No full textWe show that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation (0.25-2.5 THz) propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials
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
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