1,720,956 research outputs found
Bench-scale demonstration of CO2 capture with an electrochemically driven proton concentration process
No full textA thorough experimental investigation of a bench-scale apparatus of the proton concentration process with two symmetrical MnO2 electrodes is presented, with the aim of continuous desorption of CO2 from a K2CO3 solution. The electrodes were fabricated through cathodic deposition, and their chemical states, morphology, and microstructural architecture were characterized with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Successful formation of MnO2 film was confirmed by XPS analysis, and the SEM images showed a uniform distribution of the film across the carbon substrate surface and along the strand, with an average thickness of ∼500 nm, thus making proton ion diffusion possible. Continuous and efficient desorption of CO2 from a K2CO3 solution was obtained when electrodeposited MnO2 electrodes were used in a flow-based proton concentration process. The amount of CO2 desorbed per area of the electrode was 12-fold higher than that of a similar system. The electrochemical nature of the proton concentration process offers substantial practical advantages for the future, especially if electricity can be sustainably produced from renewable sources
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
Carbon Dioxide Capture Using an Electrochemically Driven Proton Concentration Process
Full text linkhe development of sustainable CO2 capture technologies is critical to address issues associated with global warming. In this context, the concept of an electrochemically driven proton concentration process is developed for the capture of CO2 based on modulation of the proton concentration in an electrochemical cell by a proton intercalating MnO2 electrode. The pH sensitivity of CO2 hydration is leveraged such that CO2 is absorbed as bicarbonate and carbonate ions at high pH values and desorbed as gas at low pH values. The electrochemical work requirement for the proposed proton concentration process to desorb CO2 captured from a flue gas stream is estimated to be 33.2 kJe/mol CO2, suggesting that this process is competitive with other similar electrochemical-based approaches. The experimental results show that the generated current in a symmetrical electrochemical cell with fabricated electrodes is effectively translated into proton intercalation/deintercalation reactions through reversible cycles, resulting in modulated proton concentrations
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
A novel method of CO2 capture by an electrochemically-driven proton concentration process
No full textA proton concentration electrochemical process was developed here as an alternative approach for carbon dioxide (CO2) capture. The pH sensitivity of the CO2 hydration was employed in which it can be absorbed as bicarbonate and carbonate ions at high pH and be desorbed as gas at low pH. The absorption was performed through an absorber operating with a potassium carbonate solution, while the desorption was carried in the anode compartment of an electrochemical cell where the decrease of solution pH is made by a pseudocapacitance electrode (MnO2). A comprehensive thermodynamic model was developed to determine all the speciation and the electrochemical behavior of the system. Chemical and electrochemical measurements were performed to validate the developed model, and the results showed a very good agreement between the simulated results and experimental values. MnO2 electrode was synthesized using a co-precipitation method followed by casting on either carbon cloth or carbon felt substrates. The fabricated electrodes were characterized using X-ray photoelectron spectroscopy (XPS) to assess their chemical state, where the formation of MnO2 was confirmed. The capacitance behavior of the electrodes, which is proportional to their electrochemical performance, was evaluated using cyclic voltammetry (CV). The fabricated electrodes were also tested in a symmetrical electrochemical cell where a constant potential was applied across the cell. An alternative electrodeposition strategy was employed for the fabrication of improved MnO2 electrodes. A comprehensive study to optimize the electrode fabrication by electrodeposition was done. Several experimental measurements were performed to investigate the electrodes. For example, the electrochemical performance was evaluated using electrochemical impedance spectroscopy, CV, chronoamperometry. The morphological and chemical state of the fabricated electrodes were also investigated using scanning electron microscopy and XPS. Overall, the demonstrated model and experimental data suggest that this proton concentration process could be an attractive electrochemical-based route for CO2 capture
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