1,720,995 research outputs found
Modelling and advanced quantification of inhomogeneous 3D current distribution in SOFC electrodes at the particle level
No full textIt is widely accepted that electrode microstructural characteristics significantly affect the electrochemical performance as well as the durability of solid oxide fuel cells. 3D tomography allows for the reconstruction and simulation of electrochemical phenomena within the real three-dimensional electrode microstructures. However, despite the availability of the full three-dimensional structural details, so far the microstructural analysis has been largely focused to obtaining averaged properties, such as the three-phase boundary density or the tortuosity factor, while 3D simulations have been mainly used to predict polarization curves and voltage profiles, something that can also be done with high fidelity by 1D continuum models. In order to overcome these limitations, we have recently introduced a completely new methodology for advanced microstructural characterization [1]. First we solve for the transport and electrochemical reactions of charged and gas species within the 3D electrode microstructure (Figure 1a), thus obtaining the electric potential, current density and gas concentration in every point of the corresponding phase. Then, each phase is resolved into individual particles and pores, allowing for the quantification of the statistical distribution of current and other truly-three-dimensional quantities at the particle level. The analysis allows for the identification of two classes of particles: particles which transfer more current than average, characterized by 10-40% more contacts than average, and particles which produce more current than average, which show ~2.5 times more three-phase boundary length than average (Figure 1b). These two classes of particles are mutually exclusive, so that up to the 30% of solid electrode volume is shown to be underutilized. These behaviours are confirmed in both real and synthetic microstructures. The insight gained by the exploitation of all the information contained in 3D microstructural datasets enhances the understanding of the reasoning behind inhomogeneous current distribution, with its consequent impact on lifetime, suggesting strategies for the design of more durable SOFC electrodes. The approach is also applicable to lithium-ion batteries and other electrochemical energy systems
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
Wie kann Grünes Fliegen im Ökosystem Luftfahrt gelingen?
No full textWasserstoff ist DIE Komponente, die die Luftfahrt dekarbonisieren soll. Wenn es um Nachhaltigkeit und um die Zukunft der Luftfahrtbranche geht, ist das Thema Wasserstoff kaum noch wegzudenken. Er gilt als Schlüssel zum emissionsfreien Fliegen. So vielversprechend wie das Element auch klingen mag, stellt er die Luftfahrtindustrie auch vor große Herausforderungen, die nur in Zusammenarbeit und Kooperation gemeistert werden können. In diesem Kontext stellen sich folgende Fragen:
=> Wird Wasserstoff die Lösung zur Klimaneutralität der Luftfahrtbranche sein?
=> Was sind die größten Herausforderungen bei der Ausweitung eines klimaneutralen Energie-Ökosystems und was ist notwendig, um diese zu bewältigen?
=> Was ist neben emissionsreduzierenden Antriebssystemen noch erforderlich für eine klimaneutrale Gestaltung der Luftfahrt?
=> Welche Antriebsvarianten stellen eine Option dar, den Flugverkehr klimaneutral zu gestalten bzw. klimarelevante Emissionen zu senken?Niels Kämpny: Grußwort ---
Richard Hanke-Rauschenbach: Ökosystem ---
Jens Friedrichs: Antriebssysteme ---
Nicole Dreyer-Langlet: Sicht Airbu
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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