1,720,988 research outputs found
-Conceiving a high resolution and fast X-ray CT system for imaging fine multi-phase mineral particles and retrieving mineral liberation spectra
No full textMineral liberation studies on fine particulate systems require high resolution and fast examination of a (statistically) significant number of particles. Commercial X-ray computed tomography systems allow high resolution on very small samples (say few micrometers on single particles) and only limited resolution on large particulate samples: thus they are unsuitable for fine particle liberation studies. A computed tomography system was conceived that is capable of high resolution (say micrometric or sub-micrometric) and allows imaging at once a large number of particles. It uses a detector design with a fiber optic bundle that allows enlarging the Field of View of a standard high resolution CCD in one direction. The thin particle multi-layer in a straw offers low X-ray attenuation and permits scanning with low current and voltages that in turn allows keeping small the size of X-ray focal spot and the induced geometrical un-sharpness of the projected particles
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
Pore space characterisation and permeability prediction using fast network extraction and pore throat conductance calculation
No full textState of the art X-ray micro-computed tomography (micro-CT) of reservoir rock samples and cuttings allows reconstruction of the pore network with micrometric spatial resolution that is suitable for further petrophysical and fluid flow properties evaluation. Synchrotron tomographic beam lines, compared to conventional micro-CT systems, allow better 3D representation of the pore space. The digital rock volume is used for medial axis extraction and for 3D pore space morphological characterization (i.e. connectivity, pore-body/throat size, shape factors, etc.). The medial axis is generally derived by computed intensive digital-thinning operations for skeletonization of the digital rock volume. The alternative method we describe in this work, allows to extract the 3D centered and shortest paths to follow in order to go through the pore space from any given point to another one using simple and well-established mathematical methods. Even if we do not consider explicitly fluid flow, one path can be viewed as the streamline of the fastest fluid thread for laminar flow regime that a particle follows to go through the pore space from an intrusion point to an exiting point of the digital sample. The method is very fast, processing large voxel volumes in seconds, and it is also amenable to parallelization. The conductance of the irregular cross-sections of the throats is calculated with a fast finite element method (f.e.m.) that assumes fully developed laminar flow in axial direction. The network is solved as a linear system and the absolute permeability derived. The paper reports the results of application on real oil reservoir sandstone samples and shows the potential to predict petrophysical properties from rock material (i.e. drilling cuttings or crushed side wall cores) not suitable for conventional analyses
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