1,720,973 research outputs found
Fracture in soft elastic materials: Continuum description, molecular aspects and applications
No full textA large class of materials, including polymers and biological tissues, exhibits the common
feature of high deformability under mechanical stimuli with minimum damage,
helping to achieve an extraordinary fracture toughness. In this chapter, a state of the
art on mechanics and fracture of soft elastic materials is presented, deliberately neglecting
time dependence and other dissipative mechanisms. The role played by large
deformations is discussed following a continuum-scale description. In particular, analytical
solutions of the singular near-tip stress fields for incompressible hyperelastic cracked
solids are thoroughly illustrated together with solutions coming from detailed finite element
models. Elastic crack blunting—a distinguishing feature of fracture behavior in soft materials—is described with respect to strain hardening and flaw tolerance of the
materials. The effect of blunting is also discussed with respect to the application of fracture
mechanics principles to the process of cutting in soft elastic materials. Other relevant
applications being presented in this chapter are related to experimental methods
to measure the fracture toughness of soft matter. Finally, a molecular-scale description
of polymer-like soft materials typically characterized by a microstructure made of long
polymeric chains is presented, in order to provide an insight into the inherent microscale
mechanisms leading to damage and fracture of these materials
Non-linear structural analyses of prestressed concrete girders: tools and safety formats
No full textThe main goal of this paper is the practical application of safety format methods to evaluate the structural response of pre-stressed concrete girders. Particular attention has been paid to the fully probabilistic method in which the design resistance is evaluated by probabilistic analyses. The effects of the choice of the adopted failure criterion on the standard deviation of NLFEA (non-linear finite element analysis) results are treated in this paper. Moreover, a new method to reduce the number of non-linear analyses is proposed (Fractiles Based Sampling Procedure, FBSP). With the aim to evaluate the use of mechanical parameters correlations reported in the Model Code 2010 (fib, 2013) in a probabilistic reliability analyses, a modified application of FBSP is also presented. Finally, the design resistance obtained by FBSP has been compared with the results of fully probabilistic method (FP), the classical partial safety factor (PSF) method and the alternative Estimation of Coefficient of Variation method (ECOV
DIAGNOSIS AND TREATMENT OF MULTIPLE SULFATASE DEFICIENCY AND OTHER SULFATASE DEFICIENCY
No full textMULTIPLE SULFATASE DEFICIENC
Nonlinear probabilistic shear panel analysis using advanced sampling techniques
No full textThe shear behaviour of reinforced concrete members has been studied over the past decades by various researchers, and it can be simulated by analysing shear panel elements which has been regarded as a basic element of reinforced concrete members subjected to in-plane biaxial stresses. Despite various experimental studies on shear panel element which have been conducted so far, there are still a lot of uncertainties related to what influencing factors govern the shear behaviour and affect failure mechanism in reinforced concrete members. To identify the uncertainties, a finite element analysis can be used, which enables to investigate the impact of specific variables such as the reinforcement ratio, the shear retention factor, and the material characteristics including aggregate interlock, tension stiffening, compressive softening, and shear behaviour at the crack surface. In this study, a non-linear probabilistic analysis was conducted on reinforced concrete panels using a finite element method optimized for reinforced concrete members and advanced sampling techniques so that probabilistic analysis can be performed effectively. Consequently, this study figures out what analysis methodology and input parameters have the most influence on shear behaviour of reinforced concrete panels
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
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