1,721,197 research outputs found
Perry Link, An Anatomy of Chinese : Rhythm, Metaphor, Politics, Cambridge, Mass. : Harvard University Press, 2013
No full textWenzel Christian helmut. Perry Link, An Anatomy of Chinese : Rhythm, Metaphor, Politics, Cambridge, Mass. : Harvard University Press, 2013. In: Études chinoises, vol. 33, n°1,2014. pp. 174-181
Local FEM Analysis of Composite Beams and Plates: Free-Edge effect and Incompatible Kinematics Coupling
Get PDFThe use of composite laminated structures helped in the last two decades to reduce overall weight of transportation structures. As a consequence the energy needed to power those transportation means is reduced and hence fuel and monetary resources are economized and emissions are reduced. Especially the aerospace sector has a high need of a favourable weight to power ratio. Orthotropic laminated structures are able to provide a higher stiffness combined with a lower density compared to monolithic isotropic materials used in the past. It seems hence, that they are perfect for the use in even a wider spectrum of applications. However through the assembly of differently layers, it is more difficult to model and predict the structures mechanical response to outer loadings. In the recent past different computational methods were developed. Most of them under the scope of being capable to deliver very detailed results of the global behaviour of the structure but also of the interaction between the different layers of the laminate. As a major drawback, a detailed result comes with high computational costs. Hence a need for a good compromise between costs and accuracy has to be found. This benefits especially from the fact that stress concentrations in composites occur mainly in local domains of the structure. The use of detailed models only in those local domains of interest seems therefore straightforward. Examples for such local domains with stress concentrations are laminates with free edges. At the interface between two layers with different elastic properties the stresses have singular behaviour in the immediate vicinity of the free edge, assuming linear elastic material behaviour. This is due to the material discontinuity and the resulting mismatch of the elastic properties at the interface of the layers, the condition of traction-free edges and the equilibrium between the layers. Therefore they are critical to promote delamination. An adequate analysis method for this would be the use of a full three-dimensional analysis model. However it's computational cost is significant. Composites are often rather thin planar structures, allowing the use of reduced dimensional models, which are also more attractive through their reduced computational cost. Therefore different reduced models with their appropriate hypotheses in the thickness direction are under consideration in this work. Via different thickness expansion functions suitable kinematical theories, are expressed. The Carrera's Unified Formulation (CUF) is used to have a common base to build the models with the different kinematical theories. The CUF allowing not only purely displacement based models using the Principle of Virtual Displacements (PVD), but also mixed stress and displacement based models with the Reissner's Mixed Variational Theorem (RMVT). In the first part of this work, the reduced dimensional modelling approaches are compared. Two main class are presented: Equivalent Single Layer (ESL) models treating the layered structure like one homogenous plate of equal mechanical properties, and the Layer Wise approach, treating each layer independently. Subsequently their capabilities to capture the appearing singularities are compared. In order to have a comparable measurement of those singularities, the obtained stress distributions will be expressed via a power law function, which has a priori a singular behaviour. Only two parameters fully describe therefore the singular stress components in the vicinity of the free edge. With the help of these two parameters not only the different models capabilities will be compared, but also the free edge effect itself will be measured and compared for different symmetrical laminates and the case of extensional and uniform bending load. The results for all laminates under both load cases confirm the before stated need for rather complex models in the vicinity of the free edge. However far from the free edges, in the composite plates centre, no significant difference can be noted for rather simple models. The second part of this work is therefore dedicated to the coupling of kinematically incompatible models. The use of costly expensive complex models is restricted to local domains of interest, while economic simple models will model the global domain. The Extended Variational Formulation (XVF) is identified as the most suitable way to couple the kinematically heterogenous but dimensional homogenous models. As it uses a configuration with one common interface without domain overlap, the additional efforts for establishing the coupling are limited. Further the XVF offers the possibility to adapt the conditions imposed at the interface using a single scalar parameter. It will be shown that for the homogenous dimensional problem under consideration only two different conditions can be imposed by this parameter. One matching the strong conditions imposed by the classical Multi Point Constrains (MPC) and a second one providing a weak condition. The last one is shown to provide the possibility to reduce further the domain using the complex kinematical model, without the loss of local precision. As this is the first application of the XVF towards composite structures, the need for a new coupling operator was identified. A new form is proposed, tested and its robustness will be evaluate
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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