1,720,955 research outputs found
Assessment of a NaOH-based alkaline electrolyser’s performance: System modelling and operating parameters optimisation
Full text linkMost of the scientific research is focused on KOH-based alkaline electrolysers, while NaOH-based ones are unexplored although they present interesting features. This paper presents a semi-empirical model developed in the Python environment to predict a NaOH-based alkaline electrolyser's performance to cover such a research gap and perform an optimisation procedure of electrochemical parameters. A sensitivity analysis has been carried out to study how its performance changes while varying the: i) NaOH content, ii) pressure, and iii) both. Separately, the best result has been obtained with a NaOH content and an operating pressure of 8% and 6.5 bar, respectively. Furthermore, the same values have been recorded even by varying both the NaOH content and the operating pressure. Specifically, a maximum average efficiency increase of 3.57% at 35 °C, 0.17% at 40 °C, and 3.74% at 35 °C in the case of NaOH content, pressure, and both, respectively
Energy analysis of a hydrogen integrated system in the residential sector
Full text linkNowadays, buildings are responsible for almost 40% of global energy consumption, which is addressed
by thermal (e.g., heating, cooling, and hot water) and electric (e.g., lighting and household appliances) loads. To
meet the residential energy demand and, at the same time, ensure the decarbonisation of the energy infrastructure,
hydrogen-based cogeneration systems might represent a viable solution. This work aims at evaluating the
performance of a green hydrogen integrated system consisting of a Proton Exchange Membrane (PEM)
electrolyser, hydrogen storage tanks, and a PEM fuel cell to meet both the electricity and, partially, the thermal
energy demands of a condominium located in the center of Italy. The analysis considers a single energy scenario
in which a Photovoltaic (PV) plant installed on the roof is directly connected with the hydrogen integrated system
without any withdrawal from the national grid (e.g., off-grid operation mode). Results showed that, during the
year, the user is completely self-sufficient from the electricity demand point of view. Furthermore, 22% of the
thermal need can be satisfied through the fuel cell cogeneration system
An Electrochemical Impedance Spectroscopy (EIS) analysis of a reversible Solid Oxide Cell (rSOC) for its electrochemical characterisation
No full textThe Electrochemical Impedance Spectroscopy (EIS) technique is widely used to characterise electrochemical reaction mechanisms. This technique identifies the main phenomena occurring in an electrochemical device. When dealing with Solid Oxide Electrolysers (SOECs) and Fuel Cells (SOFCs), button cells are generally used for improving their structure, choosing the right electrode materials, and testing manufacturing processes. EIS techniques are then employed to evaluate their performance under different operating conditions. However, larger industrial-sized cells are used for being operated in real test environments, meaning that a larger number of experimental tests on ever-increasing cell area are required to evaluate and assess their performance properly. In such a context, this work aims to cover this research gap by providing EIS spectra as preliminary results of an experimental campaign carried out on a 5x5 cm2 rSOC operating at different conditions in terms of temperature and gas composition. In SOEC mode, an increase in the water content at the fuel electrode leads to unstable conditions and an increase in the polarisation and ohmic resistances. In SOFC mode, a decrease in the hydrogen content at the fuel electrode leads to a maximum increase of the polarisation resistance of 34.17%, while a decrease in the oxygen content at the air electrode leads the system to highly unstable conditions. In both cases, the cell temperature variation leads to a maximum reduction in the ohmic resistance of 12 and 3.8% in SOEC and SOFC modes, respectively
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
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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