1,721,437 research outputs found
Preventing lightning damage in bearings by using mechanical preloading
No full textAbstractHigh positioned systems such as wind turbines or radar system onboard a ship can be easily struck by lightning. The lightning current has to be conducted via defined paths to prevent damage. A key element to protect is the bearing system between the rotating and stationary part. Providing a bypass current path via additional measures such as a slip ring is the conventional way of protecting bearing. The arcing due to high voltage difference between rollers and raceway is however the main cause of damage to the bearing system. It is commonly assumed that, if the wind turbine blades, or the radar, is rotating, the lubrication between the rolling elements and the raceway is a non-electrical conducting hydrodynamic lubrication layer, and thus high voltages can be developed. But if the bearing is sufficiently preloaded it is still providing a conductive path via boundary lubrication. No arcing occurs, and no damage. The concept of pre-loading the bearing system has been evaluated using many experiments on stationary and rotating bearings, and after performing endurance testing
Electromagnetic Interference of Spread-Spectrum Modulated Power Converters in G3-PLC Power Line Communication Systems
No full textThe impact of spread-spectrum techniques used to mitigate EMI from power converters on Power Line Communication (PLC) systems is studied in this paper. A buck converter, utilizing a Random Carrier Frequency Modulation with Fixed Duty cycle (RCFMFD) based control is considered as a source of conducted EMI and a narrowband G3-PLC as the victim. It is shown that, although considered to be an EMI mitigating technique, the spread spectrum technique has a detrimental effect on the communication channel, which can be explained in the framework of Shannon’s information theory. Conventional emission evaluation methods are therefore incompatible with modern day’s technology
Interfered technology: A radiant future: A look forward to EMC in 2023, five years from now
No full textIn 1973, a three-part full-page article was published in the local newspaper describing our society in the region of Twente, the Netherlands, in 1923, 1973, and 2023 [1]. The author of this article was only 11 years old at the time, but the predictions made were interesting enough to keep that article for 45 years. The article [1] predicted several innovations for 2023, 50 years ahead, such as a magnetic levitation monorail from Twente to Amsterdam reducing the travel time from 2 hours to less than 30 minutes, as shown in Figure 1. However, all we got after 45 years was a new motorway, with lots of traffic jams, and a train that still takes 2 hours. Despite over a century of research and development, maglev trains are currently operated in just three countries: Japan, South Korea, and China. Other innovations predicted in 1973 for 2023 were clothes made by printers (yes, nearly), no cars in city centres (yes), products made in Shanghai (yes), European regions instead of European countries (no, although Catalonia would like this), no manufacturing but only research and development (no), Holec and Signaal merged (no, Holec split up into several divisions now owned by Siemens, Eaton, and General Electric, and Signaal was sold by Philips to Thomson-CSF, now THALES). And the announcement that the University of Twente will be organizing a conference on communication technology, including electronics. This was a very good prediction: communication technology will be a key issue in 2023
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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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