167 research outputs found
Les danses populaires et leurs reprĂ©sentations : lâexemple du livre et de lâalbum de fĂȘte du XIXe siĂšcle
Produits luxueux recherchĂ©s par une clientĂšle aisĂ©e, lâalbum et le livre de fĂȘte du XIXesiĂšcle sont des objets privilĂ©giĂ©s pour Ă©tudier la diffusion et la rĂ©ception des danses « populaires » en suivant la logique des producteurs de ces ouvrages. Livres commĂ©moratifs Ă©ditĂ©s dans un but explicatif et pour conserver la trace matĂ©rielle dâun Ă©vĂšnement Ă©phĂ©mĂšre, destinĂ©s aux participants eux-mĂȘmes comme aux curieux de toute nature, ces ouvrages tĂ©moignent du regard portĂ© par une culture savante sur les pratiques populaires et dâun processus de rĂ©interprĂ©tation fondĂ© sur une opĂ©ration de syncrĂ©tisme culturel particuliĂšrement visible Ă travers leurs images. Deux exemples de ces livres de fĂȘtes, issus du fonds patrimonial de la bibliothĂšque de lâInstitut national dâhistoire de lâart, seront analysĂ©s pour leur intĂ©rĂȘt iconographique et textuel afin dâapprĂ©hender les reprĂ©sentations ambigĂŒes de la danse « populaire » entre les annĂ©es 1820 et 1860.Luxurious products sought after by a wealthy clientele, the album and the festive book of the 19th century are privileged objects to study the diffusion and reception of "popular" dances following the logic of the producers of these works. Commemorative books published for explanatory purposes and to preserve the material trace of an ephemeral event, intended for the participants themselves as well as for the curious of all kinds, these works bear witness to the way a learned culture looks at popular practices and to a process of reinterpretation based on an operation of cultural syncretism particularly visible through their images. Two examples of these festival books, from the heritage collection of the library of the National Institute of Art History, will be analysed for their iconographic and textual interest in order to understand the ambiguous representations of "popular" dance between the 1820s and 1860s
Calibration and monitoring of the GENEPI neutron source for the MUSE IV experiment
Rapport intern
The Thorium Molten Salt Reactor : Moving on from the MSBR
A re-evaluation of the Molten Salt Breeder Reactor concept has revealed
problems related to its safety and to the complexity of the reprocessing
considered. A reflection is carried out anew in view of finding innovative
solutions leading to the Thorium Molten Salt Reactor concept. Several main
constraints are established and serve as guides to parametric evaluations.
These then give an understanding of the influence of important core parameters
on the reactor's operation. The aim of this paper is to discuss this vast
research domain and to single out the Molten Salt Reactor configurations that
deserve further evaluation.Comment: 11 pages, 8 figures, 6 table
ADVICE, Allocation Dynamique des Voies de Circulation : Analyse systĂšme et choix technologique, livrable final de la Tache 2
Lutter efficacement contre la congestion routiÚre, améliorer durablement la sécurité des automobilistes sont deux des objectifs majeurs des gestionnaires d'infrastructures routiÚres. En milieu urbain, la congestion du trafic a un impact direct sur la qualité des transports collectifs (TC) de surface. Au-delà de leur extension, l'optimisation des infrastructures existantes et le déploiement de SystÚmes de Transport Intelligent (STI), qui rendent possible la gestion dynamique du trafic, sont une solution. Le projet ADViCe, issu d'un travail collaboratif d'un Think Tank du LUTB « SystÚmes de transport », propose d'évaluer la pertinence de la mise en place d'une stratégie d'allocation dynamique des voies de circulation. L'objectif étant d'améliorer l'efficacité des transports prioritaires (bus, pompiers, etc.) sans limiter sensiblement l'espace disponible pour les autres véhicules. Les objectifs du projet Advices sont : " Définir une méthodologie pour la mise en place d'une solution innovante de gestion du trafic " Développer les technologies adaptées et les mettre en oeuvre " Expérimenter les stratégies ADViCe " Evaluer et optimiser les scénarios de régulation Ce livrable représente le livrable final de la tache 2. Dans ce rapport nous identifierons les fonctions nécessaires à la gestion du trafic et nous décrirons les technologies permettant de les réaliser
Fast Thorium Molten Salt Reactors started with Plutonium
One of the pending questions concerning Molten Salt Reactors based on the 232Th/233U fuel cycle is the supply of the fissile matter, and as a consequence the deployment possibilities of a fleet of Molten Salt Reactors, since 233U does not exist on earth and is not yet produced in the current operating reactors. A solution may consist in producing 233U in special devices containing Thorium, in Pressurized Water or Fast Neutrons Reactors. Two alternatives to produce 233U are examined here: directly in standard Molten Salt Reactors started with Plutonium as fissile matter and then operated in the Th/233U cycle; or in dedicated Molten Salt Reactors started and fed with Plutonium as fissile matter and Thorium as fertile matter. The idea is to design a critical reactor able to burn the Plutonium and the minor actinides presently produced in PWRs, and consequently to convert this Plutonium into 233U. A particular reactor configuration is used, called unique channel configuration in which there is no moderator in the core, leading to a quasi fast neutron spectrum, allowing Plutonium to be used as fissile matter. The conversion capacities of such Molten Salt Reactors are excellent. For Molten Salt Reactors only started with Plutonium, the assets of the Thorium fuel cycle turn out to be quickly recovered and the reactors characteristics turn out to be equivalent to Molten Salt Reactors operated with 233U only. Using a combination of Molten Salt Reactors started or operated with Plutonium and of Molten Salt Reactors started with 233U, the deployment capabilities of these reactors fully satisfy the condition of sustainability
In-situ X-ray tomographic imaging study of gas and structural evolution in a commercial Li-ion pouch cell
Gas generation within Li-ion batteries (LIB) can lead to an increase in resistance, thereby, reducing their cycle lifetime. The chance of catastrophic failure via internal gas evolution may increase as a function of cell size and capacity. However, in-situ studies of gas evolution at the cell level are very limited due to limited number of techniques that can effectively probe this. Hence, for the first time, we employed high-energy X-ray tomography to non-destructively observe the structural evolution (gas and electrodes) as a function of cycle numbers for a 400 mAh commercial Li-ion pouch cell. Gas agglomeration led to cell deformation in different areas were observed in 4D (3D + time), the subsequent quantification including the volume fraction, surface area and thickness showed a heterogeneous gas distribution, revealing the degradation mechanism involving the coalescence of gas. This study demonstrates a feasible case of the use of lab-based X-ray to investigate the cell degradation and monitor state of health (SOH) by tracking the thickness in-situ, providing practical guidance for designing safer pouch cells
Reaction and proton-removal cross sections of Li, Be, B, C, ^{12N, O and Ne on Si at 15 to 53 MeV/nucleon
Excitation functions for total reaction cross sections, , were
measured for the light, mainly proton-rich nuclei Li, Be, B,
C, N, O, and Ne incident on a Si telescope
at energies between 15 and 53 MeV/nucleon. The telescope served as target,
energy degrader and detector. Proton-removal cross sections, for
Ne and for most of the other projectiles, were also measured.
The strong absorption model reproduces the -dependence of , but
not the detailed structure. Glauber multiple scattering theory and the JLM
folding model provided improved descriptions of the measured values.
radii, extracted from the measured using the optical limit of
Glauber theory, are in good agreement with those obtained from high energy
data. One-proton removal reactions are described using an extended Glauber
model, incorporating second order noneikonal corrections, realistic single
particle densities, and spectroscopic factors from shell model calculations.Comment: 16 pages, 6 figure
Analytical investigation and experimental application of the source modulation technique to measure
In recent years great interest has been displayed, worldwide, for Accelerator Driven Sub critical reactors (ADS) to incinerate the minor actinides generated by the existing energy producing reactors. In sub critical systems, the effective neutron multiplication factor is lower than 1.0 and the neutrons otherwise required to maintain the chain reaction, can be put to other uses, in particular, the destruction of nuclear wastes such as minor actinides (MA). One of the major advantages of such ADS systems is that it can be operated with very high M.A content without jeopardizing the overall safety due to a small effective delayed neutron fraction, a small Doppler temperature coefficient and possibly also a large void coefficient depending on the chosen coolant. This enhanced safety however prerequisites at all time a sufficient subcriticality margin. Reliable reactivity monitoring techniques are hence required to achieve this goal. The MUSE-4 program is a series of low power experiments carried out at the CEA-Cadarache MASURCA facility to investigate the various methods leading to the measurement of the reactivity level and associated kinetic parameters such as the effective delayed neutron fraction. The aim of this paper is to present the results obtained with a method which directly gives the ratio, for a sub critical assembly, between the reactivity Ï and the effective delayed neutron fraction ÎČeff. By combining these results to those obtained with the kp-method for the prompt neutron multiplication coefficient, we have access to the parameters which govern the prompt and the slow kinetics of a sub critical assembly. These parameters can be obtained without reference to any calibration measurement in critical configuration. It opens the way to the control of larger sub critical demonstrators which are operating with fuels which cannot be used in critical reactor, and, thanks to sub criticality, which are characterized by a deterministic safety
G Electronics and Data Acquisition (Forward-Angle Measurements)
The G parity-violation experiment at Jefferson Lab (Newport News, VA) is
designed to determine the contribution of strange/anti-strange quark pairs to
the intrinsic properties of the proton. In the forward-angle part of the
experiment, the asymmetry in the cross section was measured for
elastic scattering by counting the recoil protons corresponding to the two
beam-helicity states. Due to the high accuracy required on the asymmetry, the
G experiment was based on a custom experimental setup with its own
associated electronics and data acquisition (DAQ) system. Highly specialized
time-encoding electronics provided time-of-flight spectra for each detector for
each helicity state. More conventional electronics was used for monitoring
(mainly FastBus). The time-encoding electronics and the DAQ system have been
designed to handle events at a mean rate of 2 MHz per detector with low
deadtime and to minimize helicity-correlated systematic errors. In this paper,
we outline the general architecture and the main features of the electronics
and the DAQ system dedicated to G forward-angle measurements.Comment: 35 pages. 17 figures. This article is to be submitted to NIM section
A. It has been written with Latex using \documentclass{elsart}. Nuclear
Instruments and Methods in Physics Research Section A: Accelerators,
Spectrometers, Detectors and Associated Equipment In Press (2007
Prompt reactivity determination in a subcritical assembly through the response to a Dirac pulse
The full understanding of the kinetics of a subcritical assembly is a key issue for its online reactivity control. Point kinetics is not sufficient to determine the prompt reactivity of a subcritical assembly through the response to a dirac pulse, in particular in the cases of a large reflector, a small reactor, or a large subcriticality.Taking into account the distribution of intergeneration times, which appears as a robust characteristic of each type of reactor, helps to understand this behaviour.Eventually, a method is proposed for the determination of the prompt reactivity. It provides a decrease rate function depending on the prompt multiplication coefficient Keffp. Fitting a measured decrease rate with this function, calculated once for the reactor, gives the true value of keffp. The robustness of the method is tested. (Elsevier
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