1,720,962 research outputs found
Frattura & Fatica,metodi sperimentali e saldature
No full textL'articolo descrive brevemente le presentazioni del Seminario organizzato a Genova dal polo navale
DITEN in collaborazione con l’IIS e Scuola Politecnicacui hanno preso parte circa 150 persone. Il seminario è stato
organizzato dal Polo Navale del DITEN (Dipartimento di Ingegneria
Navale, Elettrica, Elettronica e delle Telecomunicazioni) della
Scuola Politecnica dell’Università di Genova e dall’Istituto Italiano
della Saldatura. L’evento è stato supportato dall’Ordine Ingegneri della Provincia di Genova.
L’incontro, nato come lezione universitaria e poi esteso a tutti gli interessati,
si è prefissato di offrire un’interessante opportunità di aggiornamento
delle conoscenze sotto il profilo tecnico, partendo
dagli approcci applicativi dello stato dell’arte dei metodi tradizionali,
passando per le esperienze di laboratorio fino ad affrontare limiti
e opportunità delle metodologie più recenti
A Quick and Practical Approach for Concept-design of Submerged Thin-walled Stiffened Cylinders
No full textGoal based and limit state design is nowadays a well-established approach in many engineering fields. Ship construction rules started introducing such concepts since early 2000. However, classification societies' rules do not provide hints on how to verify limit states and to determine the structural layout of submerged thin-walled stiffened cylinders, whose most prominent examples are submarines. Rather, they generally offer guidance and prescriptive formulations to assess shell plating and stiffening members. Such marine structures are studied, designed and built up to carry payloads below the sea surface. In the concept-design stage, the maximum operating depth is the governing hull scantling parameter. Main dimensions are determined based on the analysis of operational requirements. This study proposes a practical concept-design approach for conceptual submarine design, aimed at obtaining hull structures that maximize the payload capacity in terms of available internal volume by suitably adjusting structural layout and stiffening members' scantling, duly accounting for robustness and construction constraints as well as practical fabrication issues. The proposed scantling process highlights that there is no need of complex algorithms if sound engineering judgment is applied in setting down rationally the hull scantling problem. A systematic approach based on a computer-coded procedure developed on purpose was effectively implemented and satisfactorily applied in design practice
On the comparison of the dynamic response of an offshore floating VAWT system when adopting two different mooring system model of dynamics: quasi-static vs lumped mass approach
No full textThe interest in floating offshore wind turbines (FOWT) has
been growing substantially over the last decade and, after a
number of prototypes deployed [1], the first offshore floating
wind farms have been approved and are being developed. While
a number of international research activities have been
conducted on the dynamics of offshore floating HAWT systems
(e.g. OC3-Phase IV2, OC4-Phase II3), relatively few studies have
been conducted on floating VAWT systems, despite their
potential advantages [2]. Due to the substantial differences
between HAWT and VAWT aerodynamics, the analyses on
floating HAWT cannot be extended to floating VAWT systems.
The main aim of the present work is to compare the dynamic
response of the FOWT system adopting two different mooring
dynamics approaches. Two version of the in-house aero-hydromooring
coupled model of dynamics for VAWT “FloVAWT” [3]
are used: one which adopts a mooring quasi-static model, and
solves the equations using an energetic approach [4], and a
modified version of FloVAWT, which uses instead the lumpedmass
mooring line model “MoorDyn” [5]. The floating VAWT
system considered is based on a 5MW Darrieus type rotor
supported by the OC4-Phase II3 semi-submersible.
The results for the considered metocean conditions show
that MoorDyn approach estimate larger translational
displacements of the platform, compared to the quasi-static rigid
approach previously implemented in FloVAWT. As expected, the
magnitudes of the forces along the lines are lower, being part of
the energy employed for the elastic deformation of the cables. A
systematic comparison of the differences between the two
approaches is presented.
1 Previous affiliation: University of Main
Different approaches for fatigue assessment of butt-welded joints
No full textThe main aim of this work is the fatigue strength assessment of butt joints with weld reinforcement, typically used in steel works and especially in shipbuilding applications. A sensitivity analysis has been carried out by varying different geometrical parameters of the welded joints. Moreover, two different approaches for fatigue strength estimates were applied, namely the Effective Notch Stress Approach, which is nowadays widely used and it is supported by comprehensive literature and the Strain Energy Density approach. Analyses were carried out using two different finite element codes: Ansys® and Adina®. The application of different software allowed verifying the quality of obtained results, disclosing certain essential aspects related to the extrapolation of values from integration points of finite elements
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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