1,720,998 research outputs found
Numerical simulation of poly-dispersed systems
No full textMulti-size equations of Iddir and Arastoopour [2005] incorporated in the MFIX code were used to predict particle segregation and annular flow of particles in a riser section of a PSRI CFB. However, the multi-size approach requires a considerable amount of computational time when several particulate phases are considered. On the other hand, population balance equations account for the particle poly-dispersity, particularly in size, and the solution of the population balance equations (PBE) can be obtained by the method of moments requiring lower computational time. Recently, the FCMOM (Finite size domain Complete set of trial functions Method of Moments) was proposed (Strumendo and Arastoopour [2006]), a technique which provides efficiently (in terms of computational time) the solution of the PBE both in terms of the moments and in terms of the particle size distribution; the FCMOM was extensively validated for homogeneous systems. FCMOM was extended to non-homogeneous systems in which two dimensional flow equations are coupled with the population balance equations
Population balance equations' application in rotating fluidized bed polymerization reactor
No full textGas phase olefin polymerizations are now widely achieved in fluidized bed reactors. In fluidized bed poly-olefin reactors, small catalyst particles (20–80 micron) are introduced into the
bed, and when exposed to the gas flow (monomer), polymerization occurs. At early stage of polymerization, the catalyst particles fragment into a large number of small particles then the polymer particles growcontinuously, reaching a typical size of 1000–3000 micron. A successful
analysis of this process not only should account for the kinetics of the polymerization but also should include the particles mixing and particle size distribution in the reactor.
Rotating fluidized bed reactors are the promising process to have a better control on the particle size distribution, particle separation and increasing the reactor efficiency. Due to
the high rotational acceleration (e.g. 14 “g”) that can be imposed in these kinds of reactors, our preliminary results showed that the amount of throughput, i.e. monomer flow rate, can be increased without worrying of changing the fluidization regime from well mixed condition to slugging, so the production rate and in consequence the polymerization yield will increase.
In this study the population balance approach is used to describe the evolution and growth of the particle size in gas–solid rotating fluidized bed olefin polymerization reactors along
with CFD using Fluent program. The SMM (standard method of moments) method and QMOM (quadrature method of moments) method are used to solve the population balance
equations; these are coupled with the conservation equations of mass and momentum for the gas and solid phases. Simulations have been performed with; a) constant particle growth rate and b) variable particle growth rate that is a function of polymerization reaction rate
Dismissal of Acoelomorpha: Acoela and Nemertodermatida are separate early bilaterian clades
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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
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