1,721,115 research outputs found
Supporting data for: High performance polymer blend systems for HVDC applications
No full textDataset supporting 'High performance polymer blend systems for HVDC applications' published in IEEE Transactions on Dielectrics and electrical insulation during 2019.</span
High performance polymer blend systems for HVDC applications
No full textTwo polyethylene and two polypropylene blends crystallized under non-isothermal conditions were compared to a crosslinked polyethylene (XLPE) reference material. Selected blends contained a gelation agent, which forms a network structure within the material. Compared to XLPE, the blends offered higher melting points, reduced electrical conductivity, increased electrical breakdown strength, improved space charge performance and enhanced thermo-mechanical stability. Additional improvements in space charge behavior were also noted in systems containing the DBS gelation agent. The ability to provide recyclable insulation materials capable of operating at much higher temperatures than XLPE, combined with enhanced dielectric properties, may prove advantageous to cable manufacturers, particularly in renewable energy applications
Novel Insulation Materials for High Voltage Cable Systems
Full text linkCross-linked polyethylene (XLPE) has replaced oil-paper insulated systems as the primary solution for medium and high voltage AC cables decades ago, since they enable marginally higher operating temperatures and can be produced with high throughput and well-controlled extrusion technology [1]. The base for this insulation is polyethylene (PE), which can be crosslinked either with peroxide cure (involving thermal decomposition), or by grafting silane onto the polymer chains, and the use of moisture-based cure [2]. Cross-linking is deemed necessary, since commercially available, branched low-density PE (LDPE) has more significant melting at temperatures around 100°C and the material loses all of its mechanical stability. In contrast, linear high-density PE (HDPE) has a higher melting point and can achieve higher operating temperatures. But, although HDPE found some success in medium voltage cables, it has not managed to establish a foothold in the high voltage (HV) cable sector [3]. After decades of research, conventional XLPE is at the limit of its capabilities, as outlined below, and further development is bound to have diminishing returns. Further, the costs of large extrusion and catenary cross-linking manufacturing facilities and the costs and time of degassing larger cross-section HV and extrahigh voltage cables present significant sustainability issues for cable manufacturers
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
Space Charge Formation in Epoxy Resin Including Various Nanofillers
Full text linkIt has been widely anticipated that the combination of recent advances in nanocomposites technology with traditional and novel resin systems may create materials with enhanced electrical, thermal and mechanical properties. It has been recognised that charge dynamics under an electric field play an important role in determining the electrical performance of a material. In this research, the pulsed electroacoustic (PEA) technique has been used to measure space charge in epoxy anhydrite samples loaded with various nano-fillers. Space charge characteristics in both dried and wet samples have been measured at ~27 kV/mm. In addition to different charge dynamics, it has also been noticed that the electrical performance of nanocomposites has been affected in the presence of moisture. Further tests have been carried out at a lower field to reveal if different mechanisms take place
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
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