1,720,969 research outputs found
Characterization and Modeling of Reversible CO2 Capture from Wet Streams by a MgO/Zeolite Y Nanocomposite
No full textThe synthesis of CO2 sorbents capable of working on combustion flue gases is a challenging topic in the field of carbon capture and sequestration. Indeed, the presence of moisture in combustion exhausts makes most of the materials capturing CO2 through physisorption ineffective, their affinity being larger for H2O than for CO2. In this work, we investigate a novel nanocomposite sorbent based on a Mg overexchanged zeolite Y (MgOHY), showing single Mg2+ ions and nanoconfined (MgO)(n) clusters. The interaction of CO2 with the material is studied thoroughly by combining IR spectroscopy and simulation, comparing dry and wet conditions. IR spectroscopy shows that while in dry conditions the adsorption is mainly driven by the Mg2+ ions, in wet ones, the (MgO) clusters react with carbon dioxide by forming (bi)carbonate-like species. These easily decompose at mild temperatures (25-200 degrees C). Density functional theory simulations are used to investigate the origin of the CO2 interaction with representative (MgO) clusters in the periodic zeolite structure and their enthalpy of formation as a function of the water coverage. The calculations disclose a synergic effect between CO2 and H2O that, while favoring the CO2 fixation, results in the formation of (bi)carbonate-like species less stable than those formed in the absence of water
Synthesis and structural characterisation of CuII-based MOFs constructed by combining functionalised 1,4-bis(1H-imidazol-1-Yl)benzene ligands with copper sulfate
No full textAnion-pillared metal-organic frameworks (APMOFs) are a class of coordination polymers in which divalent anions connect two adjacent layers of a 2D network generated by neutral ligands and cationic metal centres. This class of MOFs is commonly composed by materials built using pyridine-based ligands and octahedral fluorinated anions as linear pillars. Only recently, the use of nitrogen based five-membered ring ligands and/or tetrahedral anions, such as sulfate, has been reported. The combination of 1,1′-(2-(trifluoromethyl)-1,4-phenylene)bis(1H-imidazole) (bibCF3) ligand with copper(ii) sulfate generates a 2D MOF (UdP-20) of minimal formula [CuSO4(bibCF3)1.5]·3H2O. UdP-20 possesses a square lattice (sql) topology in which the copper sulfate dimer molecular building block acts as 4-connected nodes and exhibits flexibility, transitioning to a closed pore phase (UdP-20-cp) upon heating. The use of different functionalised bib ligands allowed us to obtain three new examples of APMOFs: UdP-21 with 1,1′-(2-chloro-1,4-phenylene)bis(1H-imidazole) (bibCl), UdP-22 with 1,1′-(2-methyl-1,4-phenylene)bis(1H-imidazole) (bibMe) and UdP-23 with 1,1′-(2-methoxy-1,4-phenylene)bis(1H-imidazole) bibOMe. All these materials possess 2D layers connected to each other by bridging sulfate anions leading to an overall 3D anion pillared framework. All the herein reported materials were characterised by elemental analysis, thermogravimetric analysis, and powder and single crystal X-ray diffraction. Moreover, their CO2 adsorption behaviour was investigated, revealing results in alignment with what is already reported in the literature for similar materials in the case of UdP-20, while UdP-21, UdP-22 and UdP-23 exhibited moderate CO2 adsorption, due to transition to denser phases upon activation
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
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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