1,721,139 research outputs found
Design of the brazing cycle for the IFMIF/EVEDA-RFQ (Radio Frequency Quadrupole) modules using coupled thermal-structural finite element analyses
No full textIn the framework of the IFMIF-EVEDA project [1] the Radio-Frequency Quadrupole (RFQ) is a linear accelerating structure designed to both increase the energy of a 140mA Deuteron beam from 100keV to 5MeV and to focus the beam itself, by means of proper electric RF fields at the frequency of 175MHz [2, 3]. Such structure consists of 18 modules for a total length of 9.8m, made of OFE copper and AISI316LN Stainless Steel [4]. Due to the large amount of beam power (637kW) and RF power (about 600kW) as well as the necessity for the RFQ to operate in ultra-high vacuum (10-7 mbar), the component dimensions and materials adopted require the coupling of parts by means of vacuum furnace brazing performed typically in a range of temperatures between 850°C until 780°C. The deterioration of the mechanical and morphological properties of the CUC2 [5] as well as the need to limit the overall deformations of the modules (the soldering process and intermediate milling steps) induced to develop a design for a single step brazing. The main reason for this was the respect of the very tight geometrical tolerances with the corresponding need to limit beam losses under a few%. The brazing process was studied with a finite element thermal cycle considering the modules and the oven. The characterization of the component and oven geometry and materials and their thermal contacts will be described. Simplified thermal models are used for data determination, by adjusting the emissivity surface conditions and the reduction of surface area exposed. Validation is obtained by the comparison of the temperatures measured by the thermocouples on components, with the corresponding simulated ones. Thanks to a coupled thermal-structural model, which accounts for the thermal expansion curves of the adopted materials, a tailored brazing cycle could be designed. This made possible to reduce the geometric distortion of modules component with greater mass
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
Performance Optimization of the Electrostatic Accelerator for DTT Neutral Beam Injector
Get PDFThe main purpose of the Divertor Tokamak Test (DTT) facility is to study alternative solutions to mitigate the issue of power exhaust under integrated physics and technical conditions relevant for an International Thermonuclear Experimental Reactor (ITER) and a DEMOnstration Power Plant (DEMO). DTT will be equipped with a 510-keV, 40-A neutral beam injector (NBI) based on negative deuterium ion particles, designed to yield about 10 MW of neutral power to the DTT tokamak. The strongly triangular shape of the beam and the ITER-like multifocusing strategy required a different approach than more conventional solutions in designing the electrostatic plates in order to guarantee the desired beam deflection. This article describes the performance optimization process carried out for the injector of the DTT NBI system. In particular, a new electrostatic design concept for the accelerator grids has been implemented, the hyperlens grids (HGs): additional grids with a lens-like profile, imparting to each separate beamlet the necessary exit deflection without shape deformation
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
DESIGN AND HEAT TRANSFER CHARACTERIZATION OF ADDITIVELY MANUFACTURED COOLING CHANNEL PROTOTYPE FOR FUSION ENERGY APPLICATIONS
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