1,720,960 research outputs found
Structural damage detection in composite aeronautical components through methods based on digital filtering and wavelets transforms
No full textSeveral recent investigations have shown how visual inspections of mode shapes do not ensure an accurate, or even rough, identification of structural defects. This paper aims at exploring the applicability of a numerical-experimental method based on digital shape processing techniques for the identification of localised structural changes. The problem is tackled within an aeronautical context where the damage detection procedure is specifically applied to multilayered plates having symmetrically stacked layers. The examined components are used in the aeronautical industry during the manufacturing process of aircrafts and being, such structural components, an essential part for the integrity of the structure, they undergo extremely accurate investigations before becoming a part of the whole system. An interesting point here investigated is the possibility of offering a less demanding NDT alternative to those existing (i.e. ultrasonic). Several defects are simultaneously introduced into multilayered plates; these defects are simulated through a finite element model basing the model on a template derived from an ultrasonic benchmark.
In order to evaluate the influence of real measurements in the identification of localised defects, noise has been artificially introduced in the model to simulate a reduced signal-to-noise ratio in accordance with currently available laser measuring technology. The capability of the presented techniques of identifying localised defects is compared with the ultrasonic benchmark and relevant conclusions are extracted
Microwave excitation for thermographic NDE. An experimental study and some theoretical evaluations
No full textApplicazione della shearografia per il controllo dell’incollaggio di superfici in materiale composito o metallico con rivestimenti elastici multistrato ad alto potere isolante elettrico, termico ed acustico
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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
Crack shape reconstruction from ECT using Topology Costrained Optimization (TOPCSA) Algorithms
No full textModeling of thermal nondestructive evaluation techniques for composite materials and the European aerospace industry
No full textThermal non-destructive evaluation (TNDE) techniques based on IR Thermography have becoming a mature method for the aerospace industry. For the development of new procedures, the optimisation of the experimental set-up and the assessment of the inversion algorithms that are used by TNDE techniques, reference data are required, which can be provided by simulating the thermal behaviour of the inspected structures.In this work, the computerised simulation of thermographic inspection procedures by mathematical methods is investigated. The analysis is focused on the modelling strategies that can be implemented by means of commercial software packages to solve numerically the heat conduction problem in composite structures. When affordable, exact analytical solution of the heat diffusion originating during the testing procedures is reviewed as well
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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