1,720,961 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
Tunnelbrand – Abplatzverhalten von normalfesten Betonen mit verschiedenen klinkereffizienten Zementen
No full textZur Verminderung der CO2-Emissionen der Bauindustrie gewinnen klinkereffiziente Zemente immer mehr an Bedeutung und werden vermehrt in Ingenieurbauwerken eingesetzt. Das brandinduzierte Abplatzverhalten von Betonen mit diesen Zementen ist allerdings nur bedingt bekannt und ist u.a. im Tunnelbau von hoher Bedeutung. Im Zuge dessen, wurden normalfeste Betone mit vier verschiedenen Zementen (CEM I, CEM II/A-LL, CEM III/A und CEM II/B-Q) auf ihr brandinduziertes Abplatzverhalten untersucht. Die Ergebnisse zeigen, dass Betone mit klinkereffizienten Zementen zu stärkeren Abplatzungen neigen
Fire-induced spalling of normal strength concrete with different types of blended Portland cement
No full textThe cement industry is looking to reduce its overall CO2 footprint. Greener manufacturing can be achieved by the introduction of more clinker-reduced cements. Concrete exposed to fire tends to show explosive spalling caused by thermomechanical and thermohydraulic processes. It is therefore essential to determine how concretes with clinker-reduced cements behave under fire exposure, especially for concretes containing calcined clays, as these are expected to be the supplementary cementitious material of the future. In this paper, normal strength concretes with four different cements (CEM I, CEM II/A-LL, CEM III/A and CEM II/B-Q) were examined for their fire-induced spalling behaviour. In addition, a mix with PP fibres was investigated for each concrete. The experiments were conducted on ring-restrained cylindrical specimens exposed to the hydrocarbon fire curve. The results showed that the cement type influences spalling behaviour. Samples with CEM I spalled the least, followed by CEM II/A-LL and CEM III/A. Finally, samples with CEM II/B-Q showed the most severe damage. It was found that the spalling behaviour of different concretes correlates with the moisture content before exposure to fire, meaning that higher moisture content leads to higher spalling susceptibility. The use of 2 kg/m³ PP fibres completely inhibited spalling regardless of the cement type used and therefore remains a successful avoidance strategy
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
Analysis of thermohydraulic spalling in blended cement concrete
No full textThe cement industry is responsible for high CO2 emissions, which occur during the production of Portland cement clinker. To reduce These emissions, blended cements become more and more popular. Therefore, it is expected that these cements find frequent application in infrastructure and housing construction in the future. The increased use leads to a higher probability of concrete buildings with blended cements being exposed to extreme conditions such as fire. Concrete under fire can experience heavy damage in the form of explosive spalling which is caused by thermohydraulic and thermomechanical mechanisms leading to the lowering of the cross section. Furthermore, the reinforcement may be subjected directly to the fire, which can lead to a rapid decline in its load-bearing capacity.
The current state of the art showed that the cement type used can show great impact on the fire induced spalling behavior. However, large proportion of the reported spalling results took place under unsuitable testing conditions with insufficient evaluation. The smaller fraction of more profound spalling experiments showed inconsistences and contradictions, whereby no clear relation between cement type and spalling susceptibility could be drawn. Against this background in depth spalling experiments following the recommendations of RILEM TC 256-SPF of concrete with four different types of cement including Portland cement (CEM I), limestone cement (CEM II/A-LL), slag cement (CEM III/A) and Portland pozzolana cement (CEM II/B-Q) were carried out. Summarizing, CEM I concrete showed the lowest amount of spalling, followed by CEM II/A-LL and CEM III/A concrete and lastly CEM II/B-Q concrete. To understand the appearing differences in spalling susceptibility, the influence of the thermally induced moisture transport was studied by 1H-NMR relaxometry. From a thermohydraulic point of view, it was shown that initial differences of permeability and moisture content are responsible for the variations in spalling susceptibility.
Furthermore, the appearance of the moisture clog was confirmed in every sample. To further analyze the contribution of the thermohydraulic mechanism, the phase composition of the cement paste was analyzed before and after high temperature exposure regarding the dehydration behavior. Less C-S-H and portlandite were observed in CEM III/A and CEM II/B-Q pastes. However, the C-S-H seemingly showed increased thermal stability. In addition, lower amounts of AFt and AFm phases were found in blended cement pastes corresponding to lower amounts of degradation and water released at lower temperatures. In conclusion, the increased spalling proneness in blended concretes is caused by higher initial moisture contents paired with lower initial permeabilities and less amounts of early dehydrating phases. It was also shown that the addition of PP-fibers remains a successful avoidance strategy regardless of the cement type used, by increasing permeability and thus the release of water vapor
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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