1,721,053 research outputs found
Progressive interface failure under shear stresses based on a two-dimensional model of decohesion
No full textThe attention is focused on the problem of decohesion at interfaces of similar/dissimilar materials in composite structures. With reference to thin plane structures adhesively bonded to rigid substrates, tractions transmitted between opposite faces into contact as well as initiation and propagation of damage to complete decohesion are analyzed. In particular, two simplified (one- and two-dimensional) structural models are formulated and applied to simulate the standard adhesion test method on single-lap joints under shear stresses. The analytical and numerical results obtained are then used to evaluate the accuracy of the results of strength tests
Progressive interface failure of 2-layer composite beams with interlayer slip
No full textThe mechanical behavior of multi-layer structural elements (wood laminated beams, beams and columns either made of different materials or repaired with steel plates or fiber composite strips connected by adhesive bonding) is strongly influenced by the constituent materials of the layers and by their connection. The nature of the bond, in particular, strongly affects the mechanical behavior of the interfacial region and of the element itself as a consequence. A perfect connection would permit the complete transmission of the normal and shear stresses between the layers but it can hardly be obtained in practice. Thus, only a partial interaction between the layers can be realized and an interlayer slip often develops. A typical damage and failure mechanism is then represented by the initiation and propagation of decohesion zones at the interface between the layers. On increasing size of the damaged area stresses transmitted across the interface decrease and vanish when decohesion zones occur. Such a process may reduce the stiffness and the strength of the system leading to its failure. Single adhesive joints have been largely studied in the literature: many experimental, analytical and numerical studies on both failure modes and strength have been made. A large number of works exists on the mechanical response of structural elements with an elastic connection but only a little attention has been focused on the progressive interface damage and failure of multi-layer systems. This work, trying to fill this gap, develops basic understanding of the essential features of such particular failure mechanism that affects the mechanical response and strength of the structural elements in order to optimize their performance in practical applications. Starting from previous studies by the authors, wherein simple structural models of the adhesion test for the determination of the shear strength of adhesive joints were developed, and following a commonly used "multiscale approach", on the basis of the classical beam theory, a model for a two-layer beam with partial interaction between the layers is developed. Each layer is modelled as an Euler-Bernoulli elastic beam and for the connection a bilinear constitutive law is adopted. The analytical solution for each of the three phases that interface can experience (elastic, softening and detached) is obtained and employed in the solution of the nonlinear equilibrium problem by the finite element method. In order to do that, a two nodes nonlinear element with eight degrees of freedom is developed starting from the analytical solution to obtain the exact stiffness matrix. With reference to three-point bending beams, a complete simulation from damage initiation to ultimate failure of the damage process at the bond is conducted in order to investigate the mechanical response and the collapse of the system and to understand which model parameters have the main influence on them
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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