1,720,965 research outputs found
Modelling of Fireballs Generated After the Catastrophic Rupture of Hydrogen Tanks
No full textThe interest towards hydrogen skyrocketed in the last years. Thanks to its potential as an energy carrier, hydrogen will be soon handled in public and densely populated areas. Therefore, accurate models are necessary to predict the consequences of unwanted scenarios. These new models should be employed in the consequence analysis, a phase of risk assessment, and thus aid the selection, implementation, and optimization
of effective risk-reducing measures. This will increase safety of hydrogen technologies and therefore favour their deployment on a larger scale. Hydrogen is known to be an extremely flammable gas with a low radiation flame compared to hydrocarbons. However, luminous fireballs were generated after the rupture of both compressed gaseous and liquid hydrogen tanks in many experiments. Moreover, it was demonstrated that conventional empirical correlations, initially developed for hydrocarbon fuels, underestimate both dimension and duration of hydrogen fireballs recorded during small-scale tests (Ustolin and Paltrinieri, 2020). The aim of this study is to obtain an analysis of hydrogen fireballs to provide new critical insights for consequence analysis. A comparison among different correlations is conducted when predicting fireball characteristics during the simulation of past experiments where both gaseous and liquid hydrogen tanks were intentionally destroyed. All the models employed in this study are compared with the experimental results for validation purposes. Specific models designed for hydrogen can support the design of hydrogen systems and increasing their safety and promote their future distribution
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Hydrogen in Glass Sector: A Comparison between Risk-Based Maintenance and Time-Based Maintenance Approaches
No full textHydrogen can be the key to decarbonization, even for energy-intensive industries. The glass sector, for instance, burns natural gas to reach high temperatures necessary to melt the raw materials, leading to a considerable amount of CO2 emissions. Introducing hydrogen in a new sector brings many challenges in technological development, but of no less importance are the safety issues due to its hazardous properties. Hydrogen is highly flammable and can interact with many metals. Avoiding hydrogen leaks or, even worse, preventing catastrophic losses should be a priority: adopting proper maintenance planning is an effective means. In this study, the comparison of two different approaches is proposed. Time-Based maintenance is a consolidated technique that programs the operations based on the reliability data of the pieces of equipment. On the other hand, the Risk-Based Maintenance approach leads to planning the maintenance activities based on the risk evaluation. The line supplying hydrogen to the furnace is the case study considered in the analysis. The advantages of applying a methodology based on risk evaluation when handling a safety-critical system are highlighted
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