1,720,983 research outputs found
Progettazione di strutture in acciaio alla luce delle nuove normative nazionali: riflessioni pratico-applicative
No full textUn’intensa attività volta a migliorare e a semplificare la normativa per la progettazione delle strutture in acciaio è attualmente in corso sia in Italia che in Europa. Questa memoria considera la normativa italiana esaminandone alcuni aspetti di maggiore importanza, anche in relazione ai requisiti della normativa europea per la progettazione di strutture in acciaio
Esecuzione e controllo di strutture in acciaio alla luce delle nuove normative nazionali: riflessioni pratico-applicative
No full textL’esecuzione di strutture in acciaio implica il costante riferimento a specifiche regole tecniche. Questa memoria riassume alcune delle principali prescrizioni presenti nei codici normativi disponibili, tra l’altro recentemente aggiornati. In particolare le Norme Tecniche per le Costruzioni vengono analizzate unitamente alla UNI EN 1090-2, che fornisce concrete informazioni per le lavorazioni d’officina, l’esecuzione, il controllo di qualità e il montaggio
Unbraced pallet rack design in accordance with European practice- Part 1: Selection of the method of analysis
Get PDFIndustrial steel storage pallet racks are quite similar to the framed steelworks traditionally used for civil and commercial buildings: great differences are due to both the presence of boltless beam-to-column connections and to the very extensive use of thin-walled cold-formed members. Serviceability response as well as ultimate limit conditions are quite complex to predict; high engineering competences are required to guarantee significant load carrying capacities with structural systems of extremely limited weight, and, as a consequence, of very modest costs to be competitive on the market. Design standards have been recently updated worldwide; with reference to the European practice, different alternatives are now offered to designers: from the selection of the method of analysis to the approaches for the serviceability, resistance and buckling checks of the whole racks as well as of its main components. The design paths admitted by the Codes correspond to different values of the structural performances guaranteed by racks, or equivalently, to significantly different costs. A two-parts paper has been written to summarize the first research outcomes of a study on the static design rules currently adopted in Europe for steel storage pallet racks. In particular, a parametric numerical analysis has been developed on medium-rise racks of different configurations, member geometries and rotational stiffness of both beam-to-column and base-plate connections. A wide range of cases of practical interest, comprising of mono- and bi-symmetric cross-sections used for uprights, has been analyzed by means of an open source finite element program for academic use, improved by authors with a suitable beam formulation accounting for main warping effects. The present part 1 deals with the selection of the method of analysis, i.e. 1st or 2nd order elastic analysis, depending on the rack deformability to horizontal loads. Internal forces and moments on members are significantly influenced by the effects of lateral displacements as well as by the type of the beam formulation adopted in the finite element analysis program. In the following, different design alternatives are discussed: the use of the overall buckling analysis, a classical approximate method and few theoretical approaches. The rules for the resistance and stability checks of beam-column members under static loading are discussed in part 2 ("Essential Verification Checks") of this two-parts paper, together with a critical analysis of the influence of warping effects on the serviceability limit state for lateral deflection of the whole racks
Unbraced pallet rack design in accordance with European practice- Part 2: Essential verification checks
Get PDFThis paper concludes a two-parts paper focusing on the design of steel storage pallet racks in accordance with the European provisions EN 15512 "Steel static storage systems - Adjustable pallet racking systems". In part 1, "Selection of the Method of Analysis",a parametric study has been presented on medium-rise semi-continuous unbraced racks differing for components, geometries and degrees of flexural stiffness of both beam-to-column joints and base-plate connections. The choice of the method of analysis has been discussed, stressing out the influence of both the warping effects and the importance of univocal rules for designers to evaluate the elastic critical buckling loads of the overall frame as well as of the uprights (i.e, the vertical components in racks). This second part deals with rack design and considers serviceability lateral displacements of the whole rack and both resistance and stability ultimate limit states for the uprights. The different alternatives associated directly with the requirements of the design provisions. or not in contrast with them, have been discussed and applied in order to single out their differences in terms of safety index as well as in the optimal use of the material. Concluding remarks underline the weak points of the European rack standards and are of practical interest for structural engineers, stressing clearly when the recommended procedures fail, hence leading to an unsafe and uneconomic design
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
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