1,721,003 research outputs found
Cabin vibration reduction of an AB-204 helicopter using passive PZT patches
No full textPaper No. IF-08
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
Requirements and interface management for the divertor system design and integration in the Divertor Tokamak Test (DTT) facility
No full textThe construction of a Divertor Tokamak Test (DTT) facility is fully included in the European effort towards the realization of fusion energy with the aim of studying possible alternative solutions, with respect to the ITER research program, to tackle the problem of power exhaust. This means that the machine must be compatible with different possibilities for the divertor cassette design and the plasma scenario. The design of first “reference” divertor is largely based on the ITER-like divertor, but in the future other solutions are going to be tested, including liquid metal divertors. To provide a justification basis for the design of the reference cassette and guidelines for the future experimentations it is fundamental to define the requirements of this power exhaust system, in particular the heat flux compatibility and the interfaces with the surrounding interacting systems of the tokamak (the water cooling pipes, the divertor magnetic coils, the divertor diagnostics, etc.). This work shows how the divertor system can be included in a wider Requirement Management procedure that has been defined for DTT highlighting the relevant interface parameters. Additionally, a data analysis tool has been developed to provide an interactive visualization of requirements traceability to directly show the impact of changes in the divertor on the design and operations of the machine and viceversa. In this way, during future studies on alternative design divertors or plasma scenarios, the limiting constraints on both sides can be easily individuated and traced to their motivation, and possibly discussed
Design status of the Vacuum Vessel of DTT facility
No full textThe Divertor Tokamak Test (DTT) facility is an experimental facility under design and construction at ENEA C.R. Frascati. The aim of DTT is to investigate the power exhaust problem in a tokamak, providing possible alternative divertor solutions, with respect the conventional one, which can be extrapolated to DEMO fusion reactor. One of the main components of DTT facility is the Vacuum Vessel (VV), which has the function of providing an enclosed, vacuum environment for the plasma, acting also as a first confinement barrier. Starting from geometrical constraints, imposed by the desired plasma scenario and the configuration needed for the magnetic coils, the conceptual design of the VV was developed and dedicated research activities were carried out to verify design choices. A multiphysical approach was adopted with the aim of identifying a feasible and reliable solution for the VV, taking into account functional and design requirements, relevant aspects and issues. In particular, to assess and to optimize the VV design, fluid-dynamic, thermal and structural analyses were carried out, which are presented in the paper, as well as the progresses of the design
Structural Assessment of the DTT Cryostat Design
No full textThe article presents the status of DTT cryostat system and illustrates the structural verification activities performed to assess its mechanical response under various design load combinations. To this purpose, an FEM shell model of the cryostat has been developed including mechanical loads on the cryostat base due to Vacuum Vessel and Magnets, modeled as equivalent point mass. Anchoring of the base columns to the Tokamak basements has also been modeled. To verify the cryostat design, simulations have been carried out for the most critical VDEs and seismic load combinations. In addition, thermo-mechanical effects induced by both Vacuum Vessel and Magnets, on the cryostat base, have been investigated, for plasma operation and baking conditions. Further, buckling condition, under external pressure, and accidental overpressure conditions, have also been investigated
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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