323,173 research outputs found
G. S. Robinson, 1975. — Macrolepidoptera of Fiji and Rotuma. A taxonomic and geographic study
No full textRollet A. G. S. Robinson, 1975. — Macrolepidoptera of Fiji and Rotuma. A taxonomic and geographic study. In: Bulletin de la Société entomologique de France, volume 80 (9-10), Novembre-décembre 1975. p. 287
Conceptual study of a compact accelerator-driven neutron source for radioisotope production, boron neutron capture therapy and fast neutron therapy
No full textThe feasibility of a compact accelerator-driven device for the generation of neutron spectra suitable for isotope production by neutron capture, boron neutron capture therapy and fast neutron therapy, is analyzed by Monte Carlo simulations. The device is essentially an extension of the activator proposed by Rubbia [CERN/LHC/97-04(EET)], in which fast neutrons are diffused and moderated within a properly sized lead block. It is shown that by suitable design of the lead block, as well as of additional elements of moderating and shielding materials, one can generate and exploit neutron fluxes with the spectral features required for the above applications. The linear dimensions of the diffusing-moderating device can be limited to about 1 m. A full-scale device for all the above applications would require a fast neutron source of about 10(14) s(-1), which could be produced by a 1 mA, 30 MeV proton beam impinging on a Be target. The concept could be tested at the Frascati Neutron Generator, a source producing 14 MeV DT fusion neutrons at the rate of 10(11) s(-1) and located in a large shielded room. (C) 2002 Elsevier Science B.V. All rights reserved
Título: De consideratione rerum naturalium
No full textCopia digital : Google BooksLa mención de Philibert Rollet consta en colofónMarca tip. de Guillaume Rouillé (Silvestre, n. 216) en portEl impresor consta en colofónSign.: a-z\p8\s, A-D\p8\s, *\p8\sErrores de pag.: de p. 267 pasa a p. 258, y de p. 259 pasa a p. 270 y de p. 271 retrocede a p. 262Texto con apostillas marginalesErrores de pag., de p. 267 pasa a p. 258, de p. 259 pasa a p. 270 y de p. 271 retrocede a p. 26
3-D NEUTRON TRANSPORT CALCULATIONS FOR ACTIVATION AND DOSE ASSESSMENT FOR IGNITOR
No full textThe IGNITOR-ULT machine has been modelled by a 3-D neutron transport code (MCNP) and the neutron flux has been calculated in selected points of interest. Starting from these data the neutron induced radioactivity in the structures has been calculated by the inventory code ANITA in order to assess the maintenance, remote handling policy and waste managemen
Ignitor neutronics and activation
No full textThe neutron and gamma fluxes in all the main components of the projected Ignitor tokamak are calculated and discussed. The results are obtained using the 3-D Monte Carlo code mcnp with a detailed description of the device geometry and an accurate representation of the neutron source. The neutron-induced radioactivity, contact dose rates, and radiation damage of the relevant parts of the device are then derived. The consequences on the life and maintenance of device components, the exposure of personnel working in tokamak environments, and the disposal of components after shutdown are described
Radiation damage calculations for Ignitor components
No full textIgnitor is a proposed high magnetic field tokamak aimed at reaching ignition conditions in a deuterium-tritium plasma and at studying the physics of an ignited plasma for a period of a few seconds. Calculations of neutron and gamma fluxes have been performed using \ANISN\ and \MCNP\ codes. Particular attention was paid to the zones closest to the plasma and to the components most liable to be affected by radiation damage. Given the calculated gamma and neutron fluxes, the integrated doses have been computed using the \SHAMSI\ library. Neutron damage on the first wall and vacuum vessel is very small in terms of total dpa and gas production. Due to the low fluence, Ignitor components appear to have no problems of neutron damage. The toroidal magnet insulator is the only material for which the estimated damage is comparable with the maximum limit
Front des Pyrénées occidentales / Rollet, del
No full textÉchelle(s) : 1:320 000Appartient à l’ensemble documentaire : MidiPyren
Positive safety impact of Ignitor design modifications
No full textIgnitor is a proposed compact high-magnetic field tokamak aimed at studying plasma burning conditions in deuterium-tritium plasmas. A design revision of the ignitor project lead to the substitution of the graphite tiles with molybdenum ones. The consequences of this substitution from the radiological risk and environmental impact viewpoints are examined, applying a computational model for tritium inventory estimate and for activation calculation. It turns out that the global tritium inventory in the machine is almost halved by this design modification, due to a practically negligible tritium inventory in Mo. Activation of Mo is higher that that of C, however, it remains moderate. Because of this, some of the most relevant accidental sequences see a reduction of releases and of doses to public, due to radioactive source terms reduction. Graphite substitution with Mo in the first wall has therefore a global positive effect on the machine radiological safety
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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