1,721,291 research outputs found
PEEK -TiO2 composites with enhanced UV resistance
No full textIn the paper, extruded filaments of polyetheretherketone (PEEK) filled (1%v, 3%v, 5%v) with sub-micrometric titanium dioxide (TiO2) particles have been manufactured with the aim to increase the UV radiation resistance of PEEK matrix. The TiO2 particles affect crystallinity of PEEK matrix as it increases increasing filler content. The filler presence slightly increases the stiffness and the elastic modulus of resulting composites and does not influence largely the tensile strength but show an influence on the elongation at break enhancing a finger like failure mechanism ascribed to microcracks propagation and interspherulitc fracture. UV aging test showed the effectiveness of TiO2 particles in reducing the photo-degradation effect especially in 5%v filled sample resulting the most effective formulation. For this formulation, after UV aging the mechanical properties and the failure mechanism remains unchanged while the neat PEEK sample shows embrittlement and loss of ductility
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
Regional variability in the epidemiology of childhood diabetes in Italy
No full textThe incidence rates of IDDM in Italy show remarkable variability. Sardinia, a region with the second highest incidence rate in the world, co-exists with other regions with lower rates. We review and compare epidemiologic data on the incidence of childhood-onset IDDM in Italy. papers published from 1980 to 1996 reporting incidence data in Italian areas were found by search of Medline and non-indexed Italian journals. The incidence data found cover only 57% of the Italian population. The analysis of our results shows how difficult it is to make a careful study of epidemiology of IDDM in Italy. The RIDI (the Registry for Insulin-dependent Diabetes mellitus in Italy) project started in 1996 according to international guidelines. The aims is to coordinate local IDDM registries, to promote the start of new registries in uncovered areas, and to standardize registration and data collection
3D printing of polybutadiene rubber cured by photo-induced thiol-ene chemistry: A proof of concept
No full textMechanical performance of 3D printed 'Rubber-like' commercial resins are not comparable to typical vulcanized diene rubbers since they show lower strain at break. In the present work, samples made of liquid butadiene rubber have been photocured by thiol-ene chemistry and 3D printed. Morphological features and mechanical properties have been investigated by means of scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and tensile tests. The 3D printed samples show the characteristic mechanical properties of unfilled diene rubbers reaching a strain at break up to 400%
- …
