1,720,982 research outputs found
Rossi (Mario G.) Ferrari Luigi Ferrari; dalle leghe Francesco bianche al partito popolare
No full textRossi (Mario G.) Ferrari Luigi Ferrari; dalle leghe Francesco bianche al partito popolare. In: Archives de sociologie des religions, n°24, 1967. p. 218
Rossi (Mario G.) Ferrari Luigi Ferrari; dalle leghe Francesco bianche al partito popolare
No full textRossi (Mario G.) Ferrari Luigi Ferrari; dalle leghe Francesco bianche al partito popolare. In: Archives de sociologie des religions, n°24, 1967. p. 218
Development and Manufacturing of the IFMIF/EVEDA RFQ Modules
Full text linkThe IFMIF (International Fusion Material Irradiation Facility) project aim is to build a facility for the mechanical characterization of material that will constitute the wall of the nuclear reactor for DEMO (DEMOnstration power plant). The complexity of this facility, containing numerous components with peculiar specifications, requires the development of a preliminary stage for the engineeristic evaluation that will led to outline the framework of the activities, the so called EVEDA (Engineering Validation Engineering Design Activities) phase, including the LIPAc prototype construction that involve many research institutes around the world each one has in charge the realization of a line components. The description of the IFMIF project and also each contribution of the participating research institutes are briefly reported on chapter 1. Such facility require the realization of a RFQ four-vane particle accelerator, composed of 18 modules, whose part of mechanical design and construction has been entrusted respectively to mechanical design office and workshop of the I.N.F.N. Padova Unit (Istituto Nazionale di Fisica Nucleare). Since the mechanical design of the accelerator ha almost completed, we faced on the production covering over all metrological quality control phases. Metrologic control and qualification stages are strictly related to the cavity behaviour therefore we focus our attention to its working principle. Thus, in the second chapter it has been summarised the basics to understand the basic working principles of such machines, the main parameter affecting their performances and finally the main geometrical parameter of the accelerator concerned. The most critical issues arise from the production concerning the brazing process which does not permit adjustment except with re-brazing causing a strong deterioration of the mechanical properties of the copper components. It should be mentioned that brazing turned out to be an uncertainty source for the quality of the pieces , therefore, part of the activities have been carried out on the resolution of such problems. The possible causes of defect on brazed geometries have been found and one-dimensional considerations about thermal expansion as well as 3d thermo-structural simulation confirm all the statements. Such problematics has been reported on third chapter which, moreover, consists on their resolutions: the design of a new brazing cycle with an intermediate plateau. All the remaining modules are then brazed with this new cycle that permitted the disappearance of the brazing distortion. This confirms the reliability of the production phases and methods for the obtainments of modules respecting the project specifications. The quality control of the modules include: vacuum tightening test of the cavity, the coolant circuits seal test, Ultrasonic Test (UT) of the brazed joints, dimensional inspection using a CMM (Coordinate Measuring Machine) and Radio-Frequency (RF) test that identifies the electromagnetic behaviour of the single modules. These two last quality controls are strictly correlated each other in such a way that the deviations from the nominal dimensions could be used to predict the electromagnetic ones. Therefore in the last chapter, along with descriptions of the production phases and their metrological controls, it exposes a method for predicting the frequency deviation based on the deviations of measurements. The method validation is done thank to the comparison between metrological control results and those of the RF test.
To sum up, the first chapter talks about the IFMIF project, its purpose and its main components; the second summarizes the principle of operation of the four-vane RFQ and describes the main parameters of the one used for the project IFMIF / EVEDA; the third introduces the basic concepts of the brazing process, the identification of defects and determining causes by means of a thermal-structural simulation and finally outlines a new brazing cycle; the last chapter describes the main stages of production, the metrological control between them, culminating in an metrological characterization method to predict the electromagnetic behaviour of the cavity
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
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
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