1,720,954 research outputs found
Pilot crossflow absorber hydrodynamic and mass transfer data
No full textThis data was generated during a comprehensive set of experimental runs of a pilot-scale crossflow absorber. The absorber is described in the PhD thesis titled "Crossflow absorber characterisation for the direct air capture of carbon" completed by MennatAllah Labib. The data includes hydrodynamic and effective mass transfer area measurements for six Mellapak 250Y.PP structured packings of slightly different geometries
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
Crossflow absorber characterisation for the direct air capture of carbon
Full text linkCarbon capture and storage (CCS) and direct air capture (DAC) are necessary technologies in the achievement of global climate targets. Innovative ways to enhance CCS and DAC (by making them cheaper, reducing the land area required, smaller energy requirements, etc.) are being studied to facilitate accelerated large-scale, deployment of CCS and DAC globally.
One promising innovation for implementing CCS and/or DAC is using crossflow absorbers. Crossflow absorbers can operate at a wider range of fluid flowrates than counterflow absorbers, therefore, larger volumes of gas can be processed faster. Crossflow absorbers also have pressure drops that are much lower than those of counterflow absorbers, meaning their operating costs are lower. Additionally, crossflow absorbers can be built in a modular fashion (i.e., they are flexible and do not need to be tall, vertical columns) that allows them to be adapted to the needs of each specific location with minimal visual impacts.
However, liquid entrainment and liquid carryover are significant drawbacks of crossflow absorbers. Both these phenomena can reduce mass transfer efficiency, as well as result in the need for more rigorous downstream processes to condense and collect the solvent from the gas phase to prevent solvent loss to the atmosphere. Previous studies have shown that liquid entrainment and liquid carryover may be countered by changes to the packing geometry (Lavalle et al., 2018). The packing that is available for use in crossflow gas-liquid contactors is designed for cooling tower applications and is optimised for the heat transfer processes that take place in cooling towers, rather than the mass transfer processes that are needed for CCS (Holmes and Keith, 2012).
A pilot-scale test rig was developed and used to experimentally investigate the hydrodynamic and mass transfer performance of crossflow absorbers. The experimental test campaign used an air and sodium hydroxide system and the obtained data was analysed using response surface methodology (RSM). The crossflow absorber was found to have pressure drops 16% to 50% smaller than those in counterflow absorbers, and liquid holdups -50% to 200% different from those in counterflow, with the difference in liquid holdups increasing with decreasing liquid loads irrespective of packing set. Lower pressure drops can result in a lower energy requirement. The mass transfer performance of the crossflow absorber was found to be at most 15% smaller than that of counterflow absorbers.
Sulzer’s Mellapak 250Y.PP structured packing was investigated to determine its performance in crossflow absorbers, along with five other packing sets produced by tilting the Mellapak 250Y.PP at different angles to investigate the effect of tilting the packing on its performance and determine whether the packing can be optimised for use in crossflow absorbers. Out of the structured packing sets that were tested, the set tilted at 82° was found to be the one with the best performance.
The crossflow absorber’s operating conditions were optimised to maximise effective interfacial mass transfer area and minimise pressure drop. The optimum operating conditions were found to be 5.06 m/sec gas flowrate and 1.17 L/m2·sec liquid flowrate, which is equivalent to an L/G ratio of 0.3, for Sulzer Mellapak 250Y.PP packing that has been tilted 90±8°.
Finally, empirical equations for pressure drop, liquid holdup, and effective interfacial mass transfer area were developed from the experimental data collected from the crossflow absorber test rig. These empirical equations were incorporated in a preliminary rate-based model that had been developed by previous members of the CCS research group. These empirical equations reduced the model’s average absolute relative deviation (AARD) from 216% to 3.3% for pressure drop, from 512,854% to 9,305% for liquid holdup, and from 43% to 30% for effective interfacial mass transfer area
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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