1,720,988 research outputs found
Development of a model of μCHP for residential application based on SOFC planar technology
No full textCogeneration Heat and Power systems (CHP) are playing important role on world energy scenario, CHP permit a global increase of electrical efficiency and offer further improvements in terms of first and second thermodynamic law performances. Small scale systems, microCHP, are a big section of this technology field and offer a relevant market due to the fact that can be integrated in residential building and produce from city natural gas thermal heat as main output and electricity as a byproduct. A 3 kW system model was developed and global performances were evaluated both in nominal and off design conditions. The model developed in Cycle Tempo, a commercial software, integrates the Solid Oxide Fuel Cell Stack with the balance of plant (BoP) to assure hydrogen supply to the stack and heat recovery for the specific application. The stack considered is a planar geometry and the hydrogen is produced in an high efficiency external steam methane reformer (SMR). The heat is recovered from exhaust gas produced in the system after internal thermal balance is satisfied. A previous phase of the study investigates the optimal integration of all components in order to reach the most efficient layout for the system. This configuration permits up to 61% gross electrical efficiency and 98% cogeneration efficiency (LHV). A second phase evaluates system modulation, thanks to regulation parameters, in order of thermal to electrical ratio (TER) variation to meet heat residential request in a thermal logic control. The model demonstrates a feasible layout of residential system both for thermal and electrical efficiency and presents previous results of system dynamic modulation to reach instant thermal request without producing any effect on standard building heat balance
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
SOFC Thermal Transients: Modeling by Application of Experimental System Identification Techniques
No full textSolid oxide fuel cell (SOFC) is one of the most promising technologies for future power generation. In order to make this technology marketable, many issues as cost reduction, durability and operational management have to be overcome.
Therefore the understanding of thermodynamic and electrochemical mechanisms, that govern the SOFC behaviour in steady-state and in transient operation, becomes fundamental. In this context the modelling of fuel cell (FC) thermal transient is of great interest because it can predict the temperature time variation, useful to the dimensioning of auxiliary devices and to avoid unwanted operational states affecting cell durability. In the present study, a 0-D model of SOFC thermal transients was developed by applying system identification techniques, starting from experimental tests carried out on a stack made up of four single cells. Moreover, it was successfully validated in reference to further experimental data. The model allows to evaluate, in term of dynamic response, the effect of the main operating parameters on fuel cell temperature. As further result, some control/regulation considerations useful to limit thermal stresses were proposed
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
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
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