1,720,991 research outputs found
Design of a Twin Disc Test Machine
No full textTwin disc test machines are widely used to carry out
tribological tests. Often, by using these test machines
real component contact conditions, such as the contact
between gear mating teeth, are experimentally
replicated. Gearboxes are mechanical transmission
systems extensively used in the automotive and
aeronautical industries. Several R&D activities are
carried out around the world in order to improve the
performances of these components. The main areas of
R&D for these components are: design, materials and
lubricants. Bespoke gear test rigs have been built in
order to test innovative design of gears, new heat
treatments, surface coatings and lubricants. These test
systems can be grouped in three main groups (types):
Full scale gear box test systems, gear test systems and
simplified (basic) test systems. Full scale gear-boxes
development tests can be very expensive and generally
such tests are carried out only at the very last stage of
the development process and quite often only if product
certification is required. Gear test systems are most
commonly used. Normally the test sample is a single
pair of mating gears. By using this type of rig it is
possible to replicate (quite accurately) the loading and
environment conditions of a gear pair in a gearbox. Due
to the high costs of gear manufacturing the test sample
cost can often be the major cost of a test campaign. In
order to reduce test costs a first screening can be carried
out using a simplified test system known as Twin Disc
Test Machine (TDTM). In this paper the design, the
construction and the commissioning activities of a
TDTM are described. The project is being carried out by
AM Testing as part of a wider research project (Lifing
Dentature) in collaboration with the Dipartimento di
Ingegneria Civile e Industriale (DICI) of Pisa University
and Avio Propulsione Aerospaziale
Atti del 7° Workshop AIT "Tribologia e Industria"
Get PDFQuesti Atti contengono i 21 lavori presentati al 7° Workshop AIT "Tribologia e Industria". Gli argomenti spaziano in tutti i campi della Tribologia (attrito, usura e lubrificazione) con particolare attenzione alle applicazioni industriali
Experimental Tests on 280 mm Diameter Tilting Pad Journal Bearings
No full textThis paper describes the experimental characterization activity carried out on 280 mm diameter tilting pad journal bearings for turbomachines by the joint action of the University of Pisa, Baker Hughes and AM Testing using a dedicated test-rig. The static and dynamic behavior of different bearings is investigated as function of different operating parameters. The tests showed advantages and drawbacks of the different configurations indicating possible design improvements also providing validation of numerical models
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
Valutazione tossicologica degli effetti di interferenti endocrini su trota fario (Salmo trutta trutta, Linneo, 1758)
No full text
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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