1,720,961 research outputs found
Modeling and Parameter Identication for CO 2 Post- Combustion Capture by Amines Supported on Solid Sorbents
No full textA simple combined dynamic-equilibrium model of CO2 capture by a pelleted zeolite sorbent
No full textCarbon dioxide (CO2) can be effectively captured from gas mixtures by adsorption on zeolite pellets in fixed-bed columns. In this paper we start from an experimental analysis of CO2 adsorption on a sample of few pellets, to end up with a simulation model for an adsorption column filled with a large number of pellets. The initial experimental analysis is based on dedicated isothermal tests carried out with a gas adsorption analyzer. For the relation between the measured amount of adsorbed CO2 per unit sorbent mass and the input adsorption pressure and temperature, an equilibrium Three-Site Langmuir (TSL) equation is here adopted. Its unknown parameters, namely the saturation capacities, the affinities and the adsorption energies, are estimated by minimizing the error between the equation and the measures. Then, for a whole adsorption column, a simple dynamic model is worked out, based on one-dimensional partial differential equations along the column axial direction: these account basically for mass and energy conservation, for the bulk gas flow and for the porous sorbent. The overall description obtained by combining the TSL equation with the rest of the model is validated against experimental tests, consisting of inlet CO2 molar fraction steps, on a laboratory-scale column
Model-based design of a control system for the upgrade of biogas with zeolite sorbent reactors
No full textA post-combustion carbon capture process by amines supported on solid pellets - with estimation of kinetic parameters
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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
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