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Design progress of DTT divertor fixation system
Get PDFOne of the main challenges for the construction of DEMO, the first fusion demonstration reactor, is the power exhaust issue. To deal with it, EUROfusion has undertaken the construction of DTT (Divertor Tokamak Test) facility which will be held in Frascati, Italy. It aims to test various divertor models which can be integrated and used under different plasma confinement configurations. The current design of DTT embed 54 divertor cassettes which must be anchored to the vacuum vessel using suitable fixation systems. This paper deals with the initial monotonic load assessment of the fixation system of the Fixation System which must ensure compliance with multiple design requirements. The Remote Handling compatibility is one of the most demanding, since it includes a preloading phase of the divertor necessary to mitigate the shaking of the cassette due to dynamic forces. Moreover, the system must withstand the conspicuous loads acting on the Divertor due to the full or partial loss of plasma confinement (Disruptive Events). Structural verifications through Finite Element Method (FEM) have been performed on the Divertor-Fixation System, considering a set of load combinations, with particular focus on the most demanding case related to Fast-transient Vertical Disruption Event-downward
Design progress of DTT divertor fixation system
Get PDFOne of the main challenges for the construction of DEMO, the first fusion demonstration reactor, is the power exhaust issue. To deal with it, EUROfusion has undertaken the construction of DTT (Divertor Tokamak Test) facility which will be held in Frascati, Italy. It aims to test various divertor models which can be integrated and used under different plasma confinement configurations. The current design of DTT embed 54 divertor cassettes which must be anchored to the vacuum vessel using suitable fixation systems. This paper deals with the initial monotonic load assessment of the fixation system of the Fixation System which must ensure compliance with multiple design requirements. The Remote Handling compatibility is one of the most demanding, since it includes a preloading phase of the divertor necessary to mitigate the shaking of the cassette due to dynamic forces. Moreover, the system must withstand the conspicuous loads acting on the Divertor due to the full or partial loss of plasma confinement (Disruptive Events). Structural verifications through Finite Element Method (FEM) have been performed on the Divertor-Fixation System, considering a set of load combinations, with particular focus on the most demanding case related to Fast-transient Vertical Disruption Event-downward
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
Systems Engineering and Multi-criteria Decision Making Technique for Concept Design of DTT Divertor Fixation System
No full textThe conceptual design stage is one of the main challenging phases in System Engineering. Starting from the High-Level Requirements (provided by the project needs), defining the broad features and conditions that a product must ensure, different design solutions are often implemented. Several methodologies can aid whenever a decision-making process has to be performed. Among these, the Fuzzy Analytic Hierarchy Process (Fuzzy AHP) stands out, providing a rational framework for a needed decision by quantifying its criteria and alternative options, and for relating those elements to the overall goal. Fuzzy AHP centralizes the opinion of experts who, through objective and subjective opinions, can rank the conceptual alternatives. The paper deals with the assessment of components for thermonuclear reactors, in particular the design of the DTT Divertor In-Vessel Fixation System. The main requirements that the Fixation System must guarantee are strictly related to the geometric-dimensional constraints concerning the presence of the various in-vessel components. Furthermore, the Fixation System must withstand the strong loads acting on the Divertor due to the partial or full loss of plasma confinement (Disruption Events). The aim is, therefore, to identify, through Fuzzy AHP, among different alternatives, the solution which best matches the functional requirements, geometrical constraints and Remote Handling compatibility
Multiphysics FEM Integration Issues – A Case Study in Nuclear Fusion Research Activities
No full textThe engineering design phase usually requires the integration of different types of studies and analyses for the definition of the whole system. Depending on their nature, these studies can be carried out thanks to specific FEM models and tools which differ from each other on the basis of the physics problem under investigation. A proper methodology for integration of different analyses is needed, in order to transfer information and integrate the multi-physics issues. The aim of this paper is to present a methodological framework supporting the analyses integration process and the results assessment. Based on a CAD-centric approach, the framework is applied in the software Ansys Workbench, to show how to deal with this problem in such tool, thanks to the Import Load function. A study case is considered in the nuclear fusion research field: multiphysics analysis on DEMO divertor, where several physics interact with each other due to the relevant complexity of such systems. In this study, force results from FEM EM analysis are imported into the structural analyses, in order to evaluate the effect of such loads on the cassette structure. Problems dealt with concern the difference of meshes’ specifics and the varying of load interpolation settings
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