1,721,048 research outputs found
Modelling of the carburizing and nitriding processes
No full textThe thermo-chemical diffusional process of carburizing and nitriding was modeled in this study. The analysis led to the prediction of surface hardened layers dimensions and hardness in commercial steels. Diffusion model based on Fick’s laws was applied to such steels in order to describe the growth kinetics of layers, then the analytical model was employed to perform finite element calculations. In such way it was possible to calculate the carbon and nitrogen concentration in the cross sections of cylindrical samples and the consequent hardness profiles coupled with the residual stresses ones. The results from analytical model and FE calculations were compared with experimental data
Assessing the safety of the embedding system of the guide rail of the Padova's Metrobus
No full textThe Metrobus is part of the recent public transport strategy of Padova. It is based on an
innovative design developed by the Lohr Group, specialist in the design and creation of
passenger and goods transport systems. The Metrobus is a new generation of light urban
tramways, where the axle on pneumatic tyres replaces the railway boogie. The guiding of
the bus is provided by a roller “V” system linked to a single guide rail which is level with the
roadway, thus assuring accuracy of the route whilst avoiding wear and noise, avoiding also
weighing on the rail, and mechanically impossible to derail. The uniqueness of the solution of
Padova’s Metrobus in connection with the common Lohr design, is the material which is used
to embed the guide rail: a polyurethane resin matrix and inert black rubber composite.
This paper deals with the assessment of the safety of such embedded guide rail structure
design, with respect to loads induced by the Metrobus itself and by the traffic as well as
related to environmental conditions and ageing factors. The mechanical properties of the
system are first determined by solving an identification-type reverse engineering problem on
the available data coming from laboratory and in site tests. Then various FE analyses are
carried out on highly non-linear models (ANSYS) including investigation on the dynamic
answer of the system to impact forces from road traffic (LS-DYNA)
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
Advanced TTT composite materials for aeronautical purposes: Compression after impact (CAI) behaviour
No full textThe purpose of this paper is to examine the behaviour of the dry stitched composites when they are subjected to low velocity impact loads. Such composites have been laminated in combination with the Resin Film Infusion (RFI) technique. The experimental results exposed in this document are obtained from the Compression before Impact (CBI) and Compression after Impact (CAI) test efforts. The CAI behavioural determination of such composites is very important in terms of residual strength status after impact because in this case their use in primary aeronautical structures has also to satisfy the stringent Certification Requirements for Airworthiness. Traditional stitching methodologies, using Kevlar 29 threads as a 3-directional reinforcement, are compared to other advanced techniques such as the "tufting" and z-pins insertion. Following the optimization of the needle pass and the pitching line, normalized compression tests have been performed on a number of specimens which have been obtained through the utilization of different fabrication techniques in both before and after impact conditions. This has been done so as to evaluate the strength decay due to the impact damage. The subjec tests' were performed at the Alenia Aeronautica laboratories and in accordance with the AECMA ST Std prEN 6038 standards. Finally a review and a discussion of the experimental results conclude the paper. (c) 2006 Elsevier Ltd. All rights reserved
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