2,907 research outputs found

    La mort de "Mobilien" ou l'innovation au risque de la concertation

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    Consultable sur Internet : http://www.annales.org/gc/2007/gc88-06-07/gonzalez.pdfNational audienceCet article aurait pu s'intituler : " Leçon à l'usage de ceux qui veulent faire passer des idées publiques innovantes ". C'est un véritable cours de stratégie que nous donne l'auteur dans sa présentation du succès puis de l'échec de Mobilien, projet qui consistait à renforcer le réseau de bus en Ile-de-France : s'imposer dans un comité qui se révèlera essentiel, au nom d'un intérêt général supérieur, profiter d'un texte initial ambigu, coller à la vision du monde émergente : " la mobilité durable ". Oui, mais voilà, à ne pas vouloir intégrer des arguments des opposants (favorables à la voiture individuelle), à n'avoir pas fait participer des acteurs-clés (les élus, les techniciens), mais surtout à ne pas s'être appuyé sur un pilotage de projet fort pour ne pas renoncer à certains objectifs de base, ce fut un échec. Innovation et concertation ne vont pas forcément ensemble, gouvernance et pilotage non plus : il faut savoir renoncer au consensus, mais dans le cadre d'une " démocratie représentative "

    Liquid-liquid criticality in TIP4P/2005 and three-state models of water

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    Molecular dynamics simulations leading to the isothermal compressibility, the isobaric thermal expansivity, and the isobaric heat capacity of TIP4P/2005 water are found to be consistent with the coordinates of its second, liquid–liquid critical point reported recently by Debenedetti et al. [ Science 2020, 369, 289−292]. In accord with the theory of critical phenomena, we encounter that the rise in the magnitude of these response functions as temperature is lowered is especially marked along the critical isochore. Furthermore, response-function ratios provide a test for thermodynamic consistency at the critical point and manifest nonuniversal features sharply distinguishing liquid–liquid from standard gas–liquid criticality. The whole pattern of behavior revealed by simulations is qualitatively the same as the one of a three-state Ising model of water exhibiting a low-temperature liquid–liquid critical point. Exact solutions for the two-state components of such a three-state model are also provided.Agencia Estatal de Investigación | Ref. PID2020-115722GB-C22Universidade de Vigo/CISU

    Sostenibilidad de dalea lutea en bosque mixto y pastizal en tenancingo, Estado de México

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    Sostenibilidad de Dalea luteaen bosque mixto y pastizal en Tenancingo, Estado de México. El objetivo del presente trabajo fue analizar la dinámica poblacional, el comportamiento anual y evaluar la sostenibilidad ecológica de una población deD. lutea(Cav.) Willd. La presente investigación se llevó a cabo en la comunidad de Chalchihuapán, Tenancingo Estado de México (México) durante el periodo de otoño 2002 a otoño 2004. Se evaluó una población de Dalea lutea (Cav.) Willd. en bosque mixto y en pastizal inducido. Se marcaron para ello cuatro parcelas por zona y se clasificaron los individuos en tres tipos: plántulas, juveniles y adultas; los datos se trataron con análisis de varianza, prueba de medias y fórmulas de sostenibilidad. La población de D. luteaaumentó durante el verano-otoño y disminuyó durante el periodo invierno-primavera. Los muestreos presentaron diferencias estadísticas para plántulas y juveniles, no así en adultas, pero cuando estas clases se evaluaron dentro de las zonas no difirieron estadísticamente; el mayor número de individuos se reportó durante el verano, otoño e invierno de 2003. Respecto a sostenibilidad, el pastizal mostró al final del periodo un restablecimiento de 59,5 y 41% para plántulas y plantas adultas, respectivamente, y una disminución de 79% en juveniles. Mientras que en bosque mixto las plántulas y las juveniles decrecieron en 4,4 y 16,2%, y las adultas se restablecieron en 25,1%. La población de D. luteaaumentó o disminuyó conforme la época de muestreo, y el número de individuos estuvo afectado por la precipitación. Bajo las condiciones actuales de recolecta, la población de D. lutease mantuvo estable en bosque mixto y se restableció mejor en la zona de pastizal.Universidad Autónoma del Estado de Méxic

    Silica final lenses under HiPER laser fusion reactor operation conditions

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    We have studied the thermo-mechanical response and atomistic degradation of final lenses in HiPER project. Final silica lenses are squares of 75 × 75 cm2 with a thickness of 5 cm. There are two scenarios where lenses are located at 8 m from the centre: •HiPER 4a, bunches of 100 shots (maximum 5 DT shots <48 MJ at ≈0.1 Hz). No blanket in chamber geometry. •HiPER 4b, continuous mode with shots ≈50 MJ at 10 Hz to generate 0.5 GW. Liquid metal blanket in chamber design

    An overview on armor research for the laser fusion project HiPER

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    During the current preparatory phase of the European laser fusion project HiPER, an intensive effort has being placed to identify an armour material able to protect the internal walls of the chamber against the high thermal loads and high fluxes of x-rays and ions produced during the fusion explosions. This poster addresses the different threats and limitations of a poly-crystalline Tungsten armour. The analysis is carried out under the conditions of an experimental chamber hypothetically constructed to demonstrate laser fusion in a repetitive mode, subjected to a few thousand 48MJ shock ignition shots during its entire lifetime. If compared to the literature, an extrapolation of the thermomechanical and atomistic effects obtained from the simulations of the experimental chamber to the conditions of a Demo reactor (working 24/7 at hundreds of MW) or a future power plant (producing GW) suggests that “standard” tungsten will not be a suitable armour. Thus, new materials based on nano-structured W and C are being investigated as possible candidates. The research programme launched by the HiPER material team is introduced

    Impact of Computer Experience on the Viability and Repeatablity of the Moorfields Motion Displacement Test in a Developing and Underserved African Setting

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    Background: The current study was designed to explore the effect of computer experience on the viability and testretest repeatability of the Moorfields Motion Displacement Test (MMDT), a novel computer-driven glaucoma screening device, in an African community setting. Methods: 164 healthy subjects were recruited from a semi-rural Mozambican environment, and stratified according to computer experience (computer naïve: n=85, computer familiar: n=79). A suprathreshold screening test algorithm was employed, and the global probability of true damage (GPTD), testing time (TT) and false positive (FP) response rate were recorded. The visual field test was conducted twice on the same eye, and results compared to determine intra-sessional repeatability. Results: No inter-group differences in GPTD or TT (p\u3e0.05) were observed between computer subgroups, although FP response rate was significantly higher among computer naïve subjects (p=0.00 for both tests). No inter-sessional differences were observed for GPTD, TT and FP (p\u3e0.05 for all) for either subgroup. A statistically significant positive correlation was found between repeat GPTD, TT and FP measures for all subgroups (

    The Role of the Spatial and Temporal Radiation Deposition in Inertial Fusion Chambers: The case of HiPER

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    The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5–10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition of the radiation energy inside the material. In this paper, simulations on the thermal effect of the radiation–armour interaction are carried out with an increasing definition of the temporal and spatial deposition of energy to prove their influence on the final results. These calculations will lead us to present the first values of the thermo-mechanical behaviour of the tungsten armour designed for the HiPER project under a shock ignition target of 48 MJ. The results will show that only the crossing of the plasticity limit in the first few micrometres might be a threat after thousands of shots for the survivability of the armour

    TechnoFusion: new Spanish singular scientific-technical facility for fusion research

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    Technofusion is the scientific&technical installation for fusion research in Spain, based on three pillars: • It is an open facility to European users. • It is a facility with instrumentation not accesible to small research groups. • It is designed to be closely coordiated with the European Fusion Program. With a budget of 80-100 M€ over five years, several top laboratories will be constructe

    Temperature Evolution and Light Species Diffusion in Armor and Structural Material for Inertial Fusion Reactor Chambers: a Case for HiPER 4a

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    One of the most advance designs for HiPER fusion reactor is a spherical chamber 10 m in diameter based on dry wall concept. In this system, the first wall will have to withstand short energy pulses of 5 to 20 MJ at a repetition rate of 0.5-10 Hz mostly in form of X-rays and charged particles. To avoid melting of the inner surface, the first wall consists on a thin armor attached to the structural material. Thickness (th) and material of each layer have to be chosen to assure the proper functioning of the facility during its planned lifetime
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