1,720,969 research outputs found
On the influence of corrosion on the force-displacement behaviour of steel wires and strands
No full textSteel seven-wire strands are highly vulnerable to corrosion phenomena, which can strongly reduce their strength and ductility ca-pacities. In the present work, the key parameters governing the mechanical response of corroded wires and strands are identified. They include parameters related to both the geometrical configuration of the corrosion (in terms of reduction of cross-sectional area and longitudinal extension) and to the material constitutive model (strength, hardening and ductility). In this respect, both elastic-perfectly plastic and bilinear with hardening models are considered for the steel material. A simplified mechanical model describing the tensile force-displacement behavior of corroded wires and strands is proposed. The corroded strand is modelled as a parallel system of corroded wires. Parametric simulations have been then carried out in order to highlight the effects of the identified parameters, in terms of force-displacement relationship. The objective of this work is to provide an estimation of the corroded strand maximum force under tensile load, which is of great interest from both design and safety assessment points of view
L’effetto della corrosione per “pitting” sulla risposta forza-spostamento di trefoli in acciaio
No full textI trefoli in acciaio armonico risultano essere molto suscettibili a fenomeni di corrosione localizzata per pitting che ne possono ridurre significativamente la capacità resistente e deformativa, come purtroppo mostrato dal recente tragico collasso del Ponte Morandi sul Polcevera. In questa memoria vengono discussi gli effetti dovuti alla presenza di corrosione localizzata sviluppatasi lungo la direzione di sviluppo longitudinale del trefolo e caratterizzata da specifiche forme, spesso indicate in letteratura internazionale come “pits”. Viene in particolare presentata una formulazione analitica semplificata sviluppata sulla base di alcuni parametri adimensionali, dalla scala del singolo filo corroso fino all’intero trefolo corroso, che viene modellato come un sistema in parallelo i cui componenti sono costituiti dai singoli fili corrosi. I parametri adimensionali alla base del modello descrivono la configurazione geometrica della corrosione in termini di perdita di area resistente, di sviluppo longitudinale del tratto corroso e delle principali caratteristiche del legame costitutivo del materiale non corroso. In particolare si considerano legami costitutivi di tipo elastico perfettamente plastico e di tipo bilineare con diversi rapporti di incrudimento e duttilità e se ne confrontano gli effetti. Le capacità predittive del modello vengono presentate attraverso i risultati di una estesa analisi parametrica con l’obiettivo di mettere in luce gli effetti dei diversi parametri sulla risposta globale del trefolo espressa in termini di legame forza-allungamento assiale. L’obiettivo finale di questo lavoro è quello di fornire una stima della forza ultima di un trefolo corroso soggetto ad uno sforzo assiale di trazione, con evidenti risvolti applicativi sia nell’ottica di valutazioni progettuali sia nell’ottica di valutazioni di sicurezza di strutture esistenti
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
Strength reduction curves for corroded seven‐wire strands
No full textSteel seven-wire strands are highly vulnerable to corrosion phenomena, which can strongly reduce their strength and ductility capacities. Following several parametric studies already conducted on corroded wires and strands, which allowed to identify the key parameters that govern their mechanical behavior, this paper presents a new resistance model for corroded seven-wire strands. The model introduces a new coefficient that takes into account the variability of the corrosion in the seven wires that constitute the strand, with the purpose of representing the dispersion in the peak strength often emerged from tensile tests available in the literature. The lower bound of this coefficient is estimated analytically considering a brittle behavior for the wires. The ductile behavior is then taken into account by means of several Monte-Carlo simulations of corroded strands. Finally, the resistance model allows to define strength reduction curves that allow to estimate the strength of corroded strands taking into account both the geometry of the corrosion and the steel mate-rial parameters. They represent simple engineering tools that are of great interest from both a design and safety assessment point of view
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
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