1,720,977 research outputs found
Analysis of environmental damage consequences on viscous thermo elastic properties of a polymer interlayer
No full textStructural response of laminated glass elements is heavily influenced by the visco-thermo-elastic properties of polymer interlayer. Mechanical characterization of such polymers can be carried out with different experimental procedures such as creep tests, relaxation tests (both named transient tests) or tests with load or displacement periodically imposed. In the linear viscoelastic domain, mechanical parameters determined with such methods, are usually extended to time and frequency domain wider than the experimental one, translating the experimental points in the space of time or temperature, according to the time-temperature superposition principle. An incautious use of this procedure does not account for structural modifications that the polymer can suffer due to environmental actions such as solar radiation, temperature variations and moisture absorption. Here we describe the first results of an experimental campaign carried out with periodic tests on laminated glass specimens some of which previously exposed to moisture accelerated aging
Dynamic torsion tests to characterize the thermo-viscoelastic properties of polymeric interlayers for laminated glass
Full text linkThe mechanical behaviour of laminated glass is strongly influenced by the coupling capability of
interlayer that, in turn, depends on the shear modulus of the polymer. An accurate determination and
a comprehensive description of the thermo-viscoelastic properties of polymeric interlayer is necessary
to reliably predict the laminate behaviour in structural applications, both by simplified methods in which
the mechanical behaviour of the polymer is described as elastic (‘‘secant stiffness’’ approaches) and by
step by step analysis, in which articulated load and temperature histories are reproduced.
In this paper, a test procedure is proposed to perform dynamic tests on polymer interlayer, that revels
to be more simple and more reliable than the procedures presently in use; the first results of an
experimental analysis on polyvinyl butyral laminated glass specimens are reported and the generalyzed
Maxwell constitutive model obtained from the tests on the material is compared with analogous models
reported in the literature. Some case studies are considered in order to evaluate the influence of the
assumed constitutive behaviour on the response of structural elements
Mechanical characterization of visco termo elastic properties of a polymer interlayer by dynamic tests
No full textExperimental analysis of viscoelastic properties of materials is usually carried out
with creep tests, relaxation tests (both addressed as transient tests) or periodic tests. The last
method permits to perform the analysis of viscoelastic parameters at very short times, representing
the effects of fast load conditions, usually hard to highligth by transient experiments. Moreover,
experimental results of linear viscoelastic materials can be translated in the space of frequency and
temperature, so to achieve information on material behaviour in a time domain wider than the
experimental one.
Here the first results are reported of an experimental analysis caried out with cyclic tests on
composite glass specimens; some of them have been subjected to damage with exposure to solar
radiation, moisture and thermal cycles
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
Seismic structural upgrade of historical buildings through wooden deckings strengthening: the case of study of Palazzo Ducale in Parete, Italy
No full textAim of this article is to study the structural improvement of a historical wooden deckings using additional wood structural members and wood restoration techniques. Renovation of historic constructions, often performed for intended new use of buildings, cannot and must not disregard the conservation not only of the elements function, but also of materials and construction techniques. They all represent, indeed, an inestimable cultural heritage. In this context, it is paramount to seek structural improvements in deformation and strength capacity of wooden structures through the use of modern techniques compatible in typology with the original materials and construction techniques. This paper presents the case study of the wooden deckings restoration in the "Palazzo Ducale di Parete", Italy. The palace, located in the historical centre of the city of Parete in the province of Caserta, is composed of a central core (defensive tower), built probably between XI and XII century, and adjaciance blocks added in the following centuries. Apart from the central tower that rises above the rest of the palace, the building is comprised of three levels above the ground and a mezzanine. The wooden deckings were probably built before the 1700 with chestnut wood and made of a primary beam system of 25 cm diameter circular section beams, and a secondary floor distribution system with semicircular transversal elements named "panconcelle" loosely connected to beams. Structural improvement intervention consisted in the realization of a double timber crossed plank in chestnut wood, connected to principal frame through metal cylindrical shank pins, suitably sized. Where possible, the "panconcelle" were not removed from their seat to preserve the original intrados view of the floors
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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