1,721,031 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
Etude technico-économique de la production d'hydrogène à partir de l'électrolyse haute température pour différentes sources d'énergie thermique
No full textThis work focus on the techno-economic study of massive hydrogen production by the High Temperature Electrolysis (HTE) process and also deals with the possibility of producing the steam needed in the process by using different thermal energy sources. Among several sources, those retained in this study are the biomass and domestic waste incineration units, as well as two nuclear reactors (European Pressurised water Reactor - EPR and Sodium Fast Reactor - SFR). Firstly, the technical evaluation of the steam production by each of these sources was carried out. Then, the design and modelling of the equipments composing the process, specially the electrolysers (Solid Oxides Electrolysis Cells), are presented. Finally, the hydrogen production cost for each energy sources coupled with the HTE process is calculated. Moreover, several sensibility studies were performed in order to determine the process key parameter and to evaluate the influence of the unit size effect, the electric energy cost, maintenance, the cells current density, their investment cost and their lifespan on the hydrogen production cost. Our results show that the thermal energy cost is much more influent on the hydrogen production cost than the steam temperature at the outlet stream of the thermal source. It seems also that the key parameters for this process are the electric energy cost and the cells lifespan. The first one contributes for more than 70% of the hydrogen production cost. From several cell lifespan values, it seems that a 3 year value, rather than 1 year, could lead to a hydrogen production cost reduced on 34%. However, longer lifespan values going from 5 to 10 years would only lead to a 8% reduction on the hydrogen production cost.L'objectif de ce travail est d'étudier les différents éléments techniques et économiques pour la production massive d'hydrogène par le procédé d'Electrolyse Haute Température (EHT) et la possibilité d'utiliser différentes sources d'énergie thermique pour évaporer l'eau nécessaire au procédé. Parmi les sources d'énergie thermique envisagées, nous avons retenu les unités d'incinération de biomasse et de déchets ménagers, les réacteurs nucléaires à « Eau Pressurisée » (European Pressurised Reactor - EPR) et au sodium liquide (Sodium Fast Reactor - SFR). Pour chacune de ces sources, nous avons développé une étude technique concernant la production de la vapeur et ses caractéristiques. Ensuite, nous présentons la description du formalisme permettant le dimensionnement, l'évaluation économique et la modélisation des équipements constituant le procédé EHT, en particulier l'électrolyseur constitué par les cellules d'électrolyse à oxydes solides (anglais - SOEC). Finalement, le couplage des sources d'énergie thermiques avec le procédé EHT est réalisé et le coût de production d'hydrogène est déterminé pour chacune de ces sources. Ensuite, sont examinées successivement les influences du débit d'hydrogène produit, de la densité de courant imposée aux cellules, leur coût de production et leur durée de vie, du coût de l'électricité et des coûts de maintenance sur la compétitivité du procédé. Notre étude montre que le coût de production du kilogramme d'hydrogène est principalement influencé par le coût d'énergie thermique inhérent aux sources d'énergie, alors qu'il est moins influencé par la température de la vapeur produite. Il s'avère que le coût de l'électricité nécessaire au fonctionnement du procédé et la durée de vie des électrolyseurs constituent des paramètres clés pour rendre le procédé compétitif. En effet, l'électricité représente une contribution de plus de 70% dans le coût total de production d'hydrogène. La durée de vie maximale de l'électrolyseur de 3 ans au lieu de 1 an actuellement, permettrait de diminuer de 34% le coût de production d'hydrogène, mais des améliorations sur la durée de vie de 5 ans voire 10 ans ne permettraient que des réductions sur le coût de production d'environ 8%
Exergy optimization and comparison of cryogenic processes for CO2 capture
No full textInternational audienc
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
Waste heat reuse for enhanced CO2 liquefaction and reduced transport costs
No full textInternational audienc
Abstract Preview of 'Solid Carbon capture in cement f' (0BKSW5)
No full textInternational audienceProcess integration for energy savings and cost reductions has barely been considered as driver for Carbon Capture Storage and Reuse (CCSR) deployment. R&D has mainly focused on energy savings on the cement facility, CO 2 capture system and Air Separation Unit (ASU), this last when oxycombustion is considered. Amine and frosting technologies to capture CO 2 have not yet shown competitiveness and make rise several questions on energy penalty and exergy destruction. The novel approach on this work is to integrate the several technology bricks composing the future low carbon cement facility. ASU, carbon capture and gas streams of the facility are simulated. ASU streams serve to drastically reduce the energy needed to capture CO 2. This capture is performed by frost of the exhaust stream, CO 2 rich, which leads to high purity CO 2. Particular attention is paid to the kinetics of growth of CO 2 crystals. Results show that ASU + CCRS reduce cyclones size for an equivalent pressure drop compared to conventional cement facilities. Compared to the most studied Compression Capture process, integration of processes reduces by more than 20% the energy needed for CO 2 capture and lowers capital expenses for purchase of compressors. No text (if any) below this line will be printed in the abstract book
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