1,720,960 research outputs found
Alumina filled nanocomposites for electrical insulation of power rotating machines
No full textSilicone resins are widely adopted in outdoor and indoor electrical equipments. One of the main applications
includes medium power rotating machines where they are used for the impregnation of rotor and stator windings.
Due to the growing demand for compact insulation, the improvement of heat dissipation in such devices has
recently become a very important issue and dielectric materials with enhanced thermal conductivity and, at least,
unmodified mechanical and electrical properties are needed.
In the present paper, we report results about the preparation and the morphological, thermal, mechanical and
electrical characterization of new materials obtained by addition of nano-sized alumina (Al2O3) fillers to silicone
matrix. Their measured physical properties are compared with those of the unfilled matrix, used as a reference, and
the influence of the weight concentrations, ranging between 1 wt % and 7 wt % is fully discussed
Dal Monte Nuovo a Cuma: un itinerario nei Campi Flegrei tra vulcanologia ed archeologia.
No full text
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
Thermo-mechanical and electrical properties of epoxy composites containing ceramic nanofillers
No full textEpoxy-Nanocomposites with Ceramic Reinforcement for Electrical Insulation
No full textCeramic nanoparticles, that is, SiO 2 , TiO 2 ,
and Al 2 O 3 nanoparticles, with increasingly high thermal
conductivity ( k ), represent good candidates for improving
the thermophysical properties of epoxy resins. In this study,
the influence of filler addition on the thermal, mechanical,
and dielectric properties were investigated by means of
differential scanning calorimetry, dynamic mechanical anal-
ysis, and dielectric spectroscopy to measure k , storage and
loss moduli, dielectric permittivity, and volume resistivity.
Moreover, morphological investigations by scanning
electron microscopy were performed to confirm the particle
dispersion into the epoxy matrix. The results show that both
the elastic modulus and glass-transition temperature
increased with particle content. An enhancement of k was
also observed at high filler contents because of the forma-
tion of heat conductive pathways within the matrix. The
nanocomposites’ relative permittivity at 50 Hz was lower,
whereas the dielectric loss was slightly higher compared
with that of the neat epoxy matrix. A decrease in the relative
permittivity with increasing frequency, both for the unfilled
epoxy resin and epoxy–nanocomposites, was observed
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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