1,721,102 research outputs found
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
Multi-Physics Modelling towards the Stabilization of PAN Fibers with Microwaves Based on Experimental Data
Full text linkKohlenstofffasern haben gute Eigenschaften für Leichtbauanwendungen, aber
ihre Produktionskosten sind immer noch recht hoch, unter anderem wegen
des hohen Energiebedarfs und der Materialkosten. Rund 76% bis 88% der
Gesamtkosten sind die Kosten der verkauftenWare, von denen der Energiebedarf
etwa 34%ausmacht [1] . Eine Möglichkeit, den Energiebedarf zu senken,
könnte die Verwendung von Mikrowellen anstelle der herkömmlichen konvektiven
Heizung bei der Produktion sein. Ausserdem kann sich die Verwendung
von Mikrowellenerwärmung positiv auf die finale Qualität der Kohlenstofffasern
auswirken.
In dieser Arbeit liegt der Schwerpunkt auf dem ersten Erwärmungsschritt, der
Stabilisierung. Erste Schritte in Richtung einer mikrowellenunterstützten Stabilisierung
werden diskutiert.
Zum ersten Mal wurden vollständige in-situ dielektrische Messungen durchgeführt,
die die Grundlage für das Verständnis der Herausforderungen bei der
dielektrischen Erwärmung bilden. Ein mathematisches Modell, das die Reaktionskinetik
mit dem dielektrischen Verlust kombiniert, wird vorgeschlagen.
Es erlaubt den dielektrischen Verlust mit dem Stabilisierungsgrad und der
Temperatur der Fasern zu verknüpfen. Ein multiphysikalisches Modell der
Stabilisierung, das die Mikrowellenerwärmung beinhaltet, wird aufgestellt,
um den Einfluss von Prozessparametern wie Lufttemperatur, Fasertransportgeschwindigkeit
und Mikrowellenleistung auf die Faser im Vorfeld zu untersuchen.
Die experimentellen Ergebnisse werden mit dem Modell verglichen
und ausgewertet. Schließlich ermöglicht die Erweiterung eines Streumatrix-
Codes eine einfachere Entwurfsoption für zukünftige maßgeschneiderte Applikatoren
Multi-Physics Modelling towards the Stabilization of PAN Fibers with Microwaves Based on Experimental Data
Full text linkHigh energy demand is one reason for high costs of carbon fibers. One option to decrease them is to use microwave heating instead of conventional heating. In this work, steps towards a microwave assisted process during the stabilization phase are presented. In-situ dielectric measurements are performed and a reaction kinetics model is setup in connection to the dielectric loss. This allows to calculate a stabilization degree and fiber temperatures leading to a basic process understanding
Development and characterization of thiophosphate-based composite cathodes for all-solid-state batteries
No full textAll-solid-state batteries (ASSBs) with thiophosphate-based cathodes are a promising emerging energy storage technology. They offer advantages such as increased safety and energy density. However, various material and microstructure-related challenges must be overcome to optimize their performance.
This work investigates the kinetics of Li-ion conduction and diffusion in ASSB cathodes made of NCM811 active material and LPSCl solid electrolyte. Chronoamperometric rate tests are employed to quantify resistive and diffusive limitations. The results show that thin, LPSCl-rich, and fine-particulate cathodes with moderate densification pressure exhibit the best Li-ion transport kinetics. In contrast, thicker cathodes with higher NCM811 content tend to face diffusive limitations. Reducing the LPSCl particle size increases the contact area to NCM811 and mitigates these limitations, providing valuable insights for improving cathode performance and developing commercially relevant ASSB cathodes
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
Korrelation von integralen und lokalen Untersuchungsmethoden an Abgasnachbehandlungssystemen für Magermotoren
No full textIn this work the use of DRIFT spectroscopy for the investigation of molecular processes on different catalytic converters for exhaust gases of lean burn engines was investigated. The results were correlated with the outcomes of different integral measurement methods. By that, a better understanding of underlying processes resulting in certain integral observations was approached. With the help of DRIFT spectroscopy, the interpretation of HF-IS measurements on a SCR converter was improved: The already known correlation of resonance frequency and the mobility of adsorbed NH3 species was sharpened by a precise definition of the kind of mobile species. In addition to that, the influence of highly mobile [CuI(NH3)2]+ complexes on the resonance frequency was proofed. During this work, initial experiments for the correlation of integral and local investigation methods on several, technically relevant LNTs were performed. First, detailed DRIFTS investigations were correlated with high-resolution methods for material analysis such as TEM-EDX to obtain detailed information about cross effects between the different compounds and their de- or increase by different converter architectures. The results were then correlated with catalytical tests. The correlation showed a critical impact of ceria as well as barium-containing components on the NOx storage behavior. Additionally, the time-resolved formation as well as decomposition of different reaction intermediates as well as products in dependence of different LNT compositions was investigated. By that, the interpretation of measurement results from laboratory gas test bench were improved: The observed high NOx storage of one investigated catalyst was traced back to very high precious metal dispersion over the active components. Also, the use of ceria as low temperature NOx-storage was found to be critical for the performance of the LNTs during regeneration as it increases the direct oxidation of hydrocarbons and by this lowers the regeneration performance of the LNT. Additionally, an optimal dispersion of precious metals and BaCO3 were identified to be crucial to the systems performance. In the last chapter of this work the desorption of 1-Octanol from a oxidation catalyst was investigated by TP-DRIFTS. With the help of these investigations, the formation of any liquid phase during adsorption was excluded and the decomposition processes of 1-Octanol during TPO experiments were confirmed with the help of observed intermediates
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