1,721,065 research outputs found
Performance and testing of glass-ceramic sealant used to join anode-supported-electrolyte to Crofer22APU in planar solid oxide fuel cells
No full textThis work describes the performance and testing of a glass-ceramic sealant used to join the ceramic electrolyte (anode-supported-electrolyte (ASE)) to the metallic interconnect (Crofer22APU) in planar SOFC stacks. The designed glass-ceramic sealant is a barium and boron free silica-based glass, which crystallizes by means of the heat-treatment after being deposited on substrates by the slurry technique. Joined ASE/glass-ceramic seal/Crofer22APU samples were tested for 500 h in H2-3H2O atmosphere at the fuel cell operating temperature of 800 ◦C. Moreover, the joined ASE/glass-ceramic seal/Crofer22APU samples were submitted to three thermal cycles each of 120 h duration, in order to evaluate the thermomechanical stability of the sealant. The microstructures and elemental distribution at Crofer22APU/glass-ceramic and ASE/glass-ceramic interfaces were investigated. SEM micrograph observations of joined samples that underwent cyclic thermal tests and exposure for 500 h in H2-3H2O atmosphere showed that the adhesion between the glass-ceramic and Crofer22APU at either interface was very good and no microstructural changes were detected at the interfacial boundaries. The study showed that the use of the glass-ceramic was successful in preventing strong adverse corrosion effects at the Crofer22APU/glass-ceramic sealant interfac
Thermal cycling of Crofer22APU-sealant-anode supported electrolyte joined structures for planar SOFCs up to 3000 h
No full textThermal cyclic tests in air were performed for Crofer22APU/glass-ceramic/Anode-Supported-Electrolyte (ASE) joined samples for a total period of 3000 hours. Different cooling rates from the SOFC operating temperature of 800°C to room temperature were carried out. Large and elongated voids were observed to develop just below the Cr2O3/Cr-Mn spinel layer of the Crofer22APU. Diffusion of Al to the areas just below the protective oxide layer led to formation of Al2O3 on the surface of the voids. The emergence of CaAl2Si2O8 as a new phase in the glass-ceramic was attributed to the diffusion of Ca away from the interfacial areas thus decreasing the proportion of Ca to Al and Si. The glass-ceramic sealant maintained good adherence with the Crofer22APU and the ASE without presence of any crack even after 3000hrs of exposure
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
Characterization and performance of glass-ceramic sealant to join metallic interconnects to YSZ and anode-supported-electrolyte in planar SOFCs
No full textThis work describes the design, development and performance of a glass-ceramic sealant used to join the ceramic electrolyte (YSZ wafer and anode supported-electrolyte (ASE)) to the metallic interconnects (Crofer22APUand AISI 430) in planar SOFC stacks. The designed glass-ceramic sealant is a barium-free silica-based glass, which crystallizes by means of the heat treatment after being deposited on substrates by the slurry technique. The sealing process of the glass.ceramic was optimized and joined ceramic/seal/metal samples were morphologically characterized and tested for 400 h in air atmosphere followed by 200 h in H2.3H2O atmosphere at the fuel-cell operating temperature of 800 .C. The study showed that the use of the glass-ceramic was successful in joining the ceramic electrolyte to the metallic interconnect and in preventing adverse corrosion effects at the interface
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
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