1,721,009 research outputs found
The effect of the polarised cathode, formate and ethanol on chain elongation of acetate in microbial electrosynthesis
No full textReduction of CO2 to acetate in microbial electrosynthesis has been widely studied. However, the selective and quantitative production of longer chain chemicals and biofuels is still a bottleneck. Lack of sufficient energy provided by only the cathode electrode in Bio-electrochemical systems during chain elongation is one of the key challenges. It is assumed that additional electron donors than a polarised cathode is required to steer the production towards longer chain of carboxylates than acetate. In this study, formate and ethanol were supplied separately in the reactors fed by CO2 for 45 days in addition to the cathodes poised at −1.0 V vs. Ag/AgCl to investigate their effect on production. Although acetate was still the major product, supplying electron donors directed the production towards more diverse and longer chain organic chemicals than that in presence of the polarised cathode only. Significant improvement in the production of butyrate (×3.8 increase in maximum concentration) and butanol (maximum of 6.8 ± 0.3 mmol C L−1) was observed after supplying formate, while ethanol increased the diversity of the products. Supplying formate and ethanol in reactors for another 30 days under open circuit potential clarified that only ethanol could provide sufficient energy for butyrate production from acetate in the absence of polarised cathode, which reached the highest butyrate concentration of 19.1 ± 2.3 mmol C L−1. Formate was only consumed in presence of polarised cathode. It is proposed in our study that production of C4 products in presence of only cathodic electrode or cathodic electrode and formate could be associated to initial reduction of acetate to ethanol, consumed for production of C4 products through acetate. Trace levels of caproate and hexanol were detected in both reactors supplied with formate and ethanol only in the presence of polarised cathode.</p
A slurry electrode based on reduced graphene oxide and poly(sodium 4-styrenesulfonate) for applications in microbial electrochemical technologies
No full textA reduced graphene oxide slurry electrode was prepared via electrochemical reduction of graphene oxide, using anionic surfactant poly(sodium 4-styrenesulfonate) to stabilise the suspension. The slurry electrode was characterised for its electrochemical and rheological properties and tested for its application in a microbial electrochemical system under both static and fluidised conditions. Thanks to the high ratio of lateral dimension to thickness, reduced graphene oxide allowed electronic percolation at a particles loading of only 2% (wt.), which is significantly lower than typically applied with other graphitic materials such as activated carbon. The slurry displayed shear thinning behaviour, which is advantageous in real scale applications to guaranteeing homogeneity during fluidisation and to prevent sedimentation under static conditions. When tested under fluidised conditions in a microbial electrochemical device seeded with a mixed microbial consortium, the slurry enabled a 4.7x improvement of catalytic current production compared to static conditions. This approach may represent an important step toward increasing competitiveness and applicability of microbial electrochemical technologies
Preliminary evaluation of microbial fuel cells applicability to bioremediate marine sediments contaminated by polycyclic aromatic hydrocarbons
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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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