1,720,970 research outputs found
Applicability of Low-Pressure CO2 and N2 Adsorption in Determining Pore Attributes of Organic-Rich Shales and Coals
No full textLow-pressure gas adsorption (LPGA) using N2 and CO2 has been widely used by researchers to evaluate the porous structures present within shales and coals. For a suite of shale and coal samples from India, a drop in the N2-BET specific surface area (SSA) was observed with an increase in total organic carbon content (TOC), with low-TOC shales showing a higher SSA than high-TOC shales and coals. Previous research works have demonstrated the limitations of using N2 at −196 °C to penetrate complex microporous structures in coals and thus yielding a low SSA. Likewise, the limitations of N2 to decipher complex porous structures in coals will hold for shales as well. An overall trend of decreased N2-SSA with increasing TOC content, especially for shales with TOC >10 wt %, and higher N2-SSA at lower TOC levels indicates that N2 does not completely detect the porous structures in organic-rich rocks. It mostly accesses the porous structures in minerals, thereby yielding a generally high SSA for low-TOC shales. In light of these facts, correlating and evaluating SSA in shales based on organic richness and thermal maturity levels can be misleading. On the other hand, while LPGA studies using CO2 are also debated, we propose an improved relationship between organic matter abundance and CO2-SSA in coals and shales
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
Impact of Degassing Time and Temperature on the Estimation of Pore Attributes in Shale
No full textThe influence of degassing time and temperature on low-pressure gas adsorption (LPGA) behavior of shales was examined in this study. Two organic-rich shales of contrasting maturity, reactivity and organic matter type, were crushed to <1 mm and <212 μm grain-sizes and degassed at 110, 200, and 300 °C for 3 and 12 h, respectively. Our results indicate that degassing duration has a minimal influence on pore-character interpretations from LPGA experiments, while the degassing temperature shows a strong influence on the pore attributes. For both shales, reliable porosity estimates were obtained when the samples were degassed at 110 °C. When the degassing temperature was increased to 200 and further to 300 °C, distinct changes in adsorption isotherms and other pore structural features were observed. For the mesoporous low-mature shale (collected from a lignite mine) when the degassing temperature was kept at 200 °C, a macroporous character was induced with a manifold increase in pore diameter. Results from thermogravimetry and Rock-Eval indicate abundance of reactive kerogen, which undergoes alteration when degassed at higher temperatures. When the degassing temperature was kept at 300 °C, the organic matter underwent further alteration and showed an isotherm similar to the shales degassed at 110 °C. Similarly, for the oil-window mature shale sample, a transition towards macroporous structure was observed when the sample was degassed at 200 and 300 °C, compared to a mesoporous structure observed when degassed at 110 °C. The results from fractal dimensions also support the above inferences, indicating the presence of simpler structures at higher degassing temperatures. Reduction in pore volume (110–200 °C) and its further rise (200–300 °C) are also evident in the micropore domain, more distinctly in the oil window mature shale. Our results strongly indicate that degassing temperature should be kept at around 110 °C for reliable shale pore character estimation
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
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