Les 15 èmes Journées Scientifiques de Marcoule 9 – 10 juin 2015
Document propriété du CEA – Reproduction et diffusion externes au CEA soumises à l’autorisation de l’émetteur
In-situexperiments at elevated temperatures - an invaluable aid in studying MOX.
HEXRD was used to track transformation kinetics of the martensitic and bainitic transformations [3,5–7] and also, even if more difficult, the carbide precipitation  occurring during the Q&P process. By giving access to the lattice parameter of phases, it permits at the same time to determine both the mean carbon enrichment and the intense second-order internal stresses in austenite during the partitioning step . Since insitu HEXRD experiments allow deconvoluting unambiguously these chemical and mechanical contributions, it is thus the sole reliable method to follow carbon enrichment in austenite during a Q&P process. All these metallurgical parameters have been obtained by determining the mean position of diffraction peaks and their relative integral breaths as a function of time and temperature. However, to our best knowledge, the time resolved evolutions of the width and the shape of the diffraction peaks of austenite along a Q&P thermal treatment have not been studied in details so far, despite they comprise an important source of information about phase states. By analyzing such peaks during insituexperiments, Guo et al.  and Rementeria et al.  have revealed that the austenite films and blocks produced during bainitic transformations show different carbon enrichments.
Temperature is the most usually employed stimulus for actuating liquid crystalline elastomers but light or electric fields have been also considered [5,6]. Liquid crystalline elastomers containing an inorganic material may offer new original solutions for the development of other stimuli-responsive materials, making use of the intrinsic properties of the inorganic nuclei. For instance, dispersing magnetic particles within these elastomers could provide shape-changing materials by means of an applied magnetic field during the isotropic/mesogenic phase transition. Moreover, the use of magnetic particles should enhance the magneto-orientational response of liquid crystals, as first proposed by Brochard and de Gennes in the 1970s  then experimentally tested some years later. The as obtained doped nematic liquid crystals could be oriented by a magnetic field intensity 10 3 times smaller than usual [8,9].
Le p rocessu s d e vieillissem en t d e la m ou sse d e p olyu réth an e d ép en d d ’u n certain n om bre d e facteu rs, p ar exem p le les caractéristiques chimiques et morphologiques d e la m ou sse, le typ e d e gon flan t et son in teraction , ou l’ép aisseu r d u m atériau . C’est en gran d e p artie cette d ern ière qu i con d i- tion n e la con servation d e la p erform an ce th erm iqu e in itiale d e la m ou sse, car l’air am bian t m et p lu s d e tem p s à attein d re tou tes les cellu les d ’u n isolan t ép ais. Si le p rod u it n ’a p as été testé et qu e sa RTLT n ’est p as con n u e, il fau t ap p liqu er les valeu rs in d iqu ées au tableau 2 au x MPP fabriqu ées con form ém en t au x n orm es en vigu eu r.
Perhaps the most important lesson I have learned during my period as PhD student is that science is a matter of collaboration. I am much obliged to all who helped me and shared with me this experience. Without any doubt, the work here presented would not have been possible without the aid of my advisers and colleagues. First person to acknowledge is, Dr. A. Jankowiak, for his guidance, “savoir-faire” and patience—even when things did not worked as expected. Also, my acknowledg- ments go to Dr. S. Miro, who played an important role during all the PhD period, specially during the ion-irradiation and Raman spectroscopy campaigns, and to Dr. J.M. Costantini, whose vast knowledge impressed me since the beginning and was source of many good hints. I would like to thank P. Chapelot and L. Nicolas for they welcome to the SRMA/LC2M and their endorse to this research project. Also, my acknowledgments go to all those who helped me during the experimental procedures: To E. Bordas, F. Lepretre, H. Martin, Y. Serruys and L. Beck from JANNUS-Saclay, A. Debelle and L. Thom´e from JANNUS-Orsay, and I. Monnet, C. Grygiel and T. Madi from GANIL for their support during the irradiation campaigns. To P. Bonnaillie, R. Podor and E. Meslin for their support with the SEM, E-SEM and TEM characterization. To T. Vandenberghe, for his support in multiple tasks—specially those concerning long nights side by side running the insitu tensile tests and, finally, to D. Troadec and Mr. B. Arnal for the preparation of the samples for TEM observations.
Co nanostructures are small (|F Co | ≪ |F DN |), the |F Co | 2 term is negligible in Eq. 5.8. The interference term which
contains the information on the position of the nanostructures is obtained by subtracting the GISAXS data after and before Co deposition. Two high symmetry sites are possible for the localization of the Co dots: above the crossing point of the dislocation lines or at the center of the square formed by four dislocation lines. By symmetry any other possibility gives more than one nanostructure per unit cell. This is not expected because there is one nucleation site per unit cell and the diffusion length of Co atoms is large at the chosen temperature to avoid any homogeneous nucleation. To obtain the position of the Co nanostructures, it was necessary to describe precisely the interference effect along the scattering rods. Since the form factor of the dislocation network has been previously determined, only the form factor of the Co nanostructures and the position in the unit cell is lacking. The quantitative analysis of the interference effect has been performed again in the framework of the DWBA tacking into account the Ag thin film which modifies the reflection properties of the surface. To calculate the interference between the waves scattered by the nanostructures and the dislocations (equation 5.8) nine terms have been calculated (respectively four and five for the nanostructures and the dislocations). To give an explicit expression of the calculation, the Co dots were modeled with a cylindrical shape with an integer number of atomic planes in the height. The best fit has been obtained for Co dots localized
Après avoir rappelé le principe de la diffusion et l’état de l’art sur les méthodes de mesure existantes (Chapitre 1), nous étudierons dans une première partie un nouveau protocole de caractérisation insitu de la dispersion par une surface diffusante, visant à combler la lacune des premiers volets de la norme ISO 17497 qui ne permettent des mesures qu’en laboratoire. Afin d’évaluer la sensibilité de la méthode aux paramètres, une simulation acoustique en 2D a été réalisée. Ces premières indications ont permis une série de tests expérimentaux de mesure du coefficient de dispersion dans des conditions insitu, à mettre en parallèle avec le coefficient ISO mesuré en laboratoire (Chapitre 2). Dans une dernière partie (Chapitre 3), nous étudierons l’évolution de nouveaux paramètres calculés sur réponse impulsionnelle en fonction de l’arrangement de diffuseurs. Faute de temps, les réponses impulsionnelles ne seront pas mesurées insitu, mais simulées à partir d’un modèle simplifié du Boston Symphony Hall.
décrites comme scientifiques. À plusieurs reprises, non sans une sensation de déstabilisation, les actions et les propos des danseurs rencontrés ont témoigné d’un décalage entre la ville qu’ils vivaient et celle que je croyais connaître. Cette communication, sous forme de témoi- gnage, mettra notamment en lumière le caractère heuristique d’une rencontre entre arts et sciences, mais aussi les difficultés potentielles liées à une hybridation de ces deux mondes. Avant d’aller plus loin, il sera nécessaire de prendre le temps de décrire le rapport de danseurs insitu aux territoires, ici urbains. Il sera alors plus aisé de montrer en quoi cela peut question- ner les sciences du territoire et une hybridation potentielle.
L’écriture insitu : en voyage sur la mer de glace FICTION Aimée Laberge (auteure)
Que se passe-t-il quand un espace imaginaire se métamorphose en espace de réalité, et comment cette réalité marquera-t-elle le texte d’une œuvre de fiction? C’est à l’invitation de Louis Fortier, directeur du projet CASES (Canadian Arctic Shelf Exchange Studies), que j’ai pu me joindre à une équipe internationale d’océanographes polaires à bord du brise-glace Amundsen en novembre 2003. Le but de ce voyage dans l’Arctique de l’ouest était d’observer le processus d’échantillonnage scientifique, puisque le personnage principal de mon roman allait être une biologiste spécialiste des algues de glace. Ce texte se veut non pas un commentaire sur une expérience de lecture de la nordicité littéraire, mais plutôt le compte rendu d’une expérience d’écriture insitu.
et al., 1990). In addition, the calculated lattice parameters of - hydride that formed after the to transformation are marginally larger than the lattice parameters obtained by Singh et al. (2007) at 500 C. These indicate that the actual temperature of the Zr powder in the reaction cell when the - Zr phase was observed was significantly higher than that measured by the thermocouple connected to the sample holder for a couple of fractions of a second during the early stages of the reaction. We believe that such a high temperature rise occurs because of the very high reactivity of a powder (compared with a solid) caused by its higher surface-to-bulk ratio. The heat produced during the exothermic reactions of hydrogen solvation and hydride formation would, thus, raise the local temperature of the powder significantly for a brief time and not be recorded by the thermocouple situated some distance away from the powder on the sample holder. In order to avoid such temperature mismatch, we suggest (1) to use an extra thermocouple or place the existing thermocouple closer to the reactant powder; (2) mix Zr powder with another well defined standard powder sample to use them as a reference for extracting the temperature from the thermal expansion; (3) reduce the hydrogen loading pressure to slow down the hydrogen absorption rate.
Vague, mesure, impact, digue, aération
In order to study in-situ wave impact pressure on coastal structure, the Artha breakwater was equipped by two high frequency sensors on its western extremity. These sensors recorded pressure at 10 kHz for 10 minutes every hour from January 2016 to April 2016. During the same period, offshore swell was measured by a directional wave buoy 1km from the breakwater while wind and water level were recorded at the semaphore and tide gauge of Socoa. Pressure measurement are in agreement with previous field experiments (,), showing peak pressure relatively weaker than those measured in wave flumes . The breakwater’s armor unit is likely to generate complex effects which could minimise impacts. One of the aims of this study is to identify the environmental conditions (swell, water level and wind) that generate the strongest impacts. A first statistical analysis of the environmental datas confirmed the randomness of the phenomenon. Each impact were then studied individually and two types of impact were distinguished. The first and more numerous class present relatively slow impacts which intensity stays relatively close to hydrostatic. The second class present faster and more intense impacts happening for relatively weak wave heights. The potential compression effect of entrapped pockets of air is studied in order to explain those pressures. During the next measurement campaign 22 pressure sensor will be deployed on the breakwater allowing a better understanding of the phenomenon.
planing is controversial. This is possibly due to the poor retention of Elyzol ® gel within periodontal pocket . Similarly, the clinical efficacy of Periochip ® , a biodegradable insert consisting of chlorhexidine gluconate in hydrolyzed gelatin was not confirmed. This biodegradable, adhesive insert can sustain drug release over 7 days. Although, following a systematic review enrolling 5 clinical studies, the microbiological and clinical results on Periochip ® in conjunction with scaling and root planing therapy are limited and controversial . Besides, the 2 % minocycline gel which has been commercialized under several trademarks: Dentomycin ® , Periocline ® and Parocline ® seems to be good in clinical therapy. Adjunctive Dentomycin ® was reported to provide significant probing depth reduction and clinical attachment gain  as well as more advantageous outcomes in bleeding on probing . However, these gels still lack of biodegradability, leading to the need of removal of the empty device after treatment. A biodegradable injectable system that was broadly studied is Atridox ® . This system consists of a biodegradable polymer PLA dissolved in a biocompatible solvent NMP with 10 % doxycycline hyclate drug loading. It is an insitu forming system due to its change from liquid to solid state after injection into periodontal pocket. This implant can sustain drug release over 7 days. In a very large clinical study (n = 822), Atridox ® performed both clinical and statistical superiority for all parameters when compared to oral hygiene and the vehicle alone .
1 Introduction and objectives
Researches in ad hoc networks field have reached a stage where experiments have become necessary. Most of these researches concern the design of protocols (MAC, routing, mul- ticast, QoS, security) that are mainly evaluated by theoretical analysis or by simulations (on simulators like NS2, GloMoSim or Opnet). Detailed and realistic simulations are hard to conduct because of the numerous software layers to take into account and the large de- pendence toward environmental factors. The most used simulators necessarily have to make some compromises to allow researchers to rapidly test the general behavior of the protocols they are working on. At present, the community agrees on the fact that there is an obvious lack of real experiments of these protocols. A few real world testbeds have been proposed in [1, 2, 3, 4]. These works generally aim at depicting the behavior of some particular routing protocol (DSR routing protocol for [3, 4], ABR for  and AODV and OLSR for ). But it is extremely difficult to differentiate in them the effects due to physical and MAC (medium access control) layers from the effects due to routing or others layers protocols.
Threat and Punishment in Public Good Experiments * David Masclet † , Charles N. Noussair ‡ , Marie-Claire Villeval §
Résumé / Abstract
Les agents n’hésitent pas à sanctionner les resquilleurs dans des situations de dilemmes sociaux et cela a un effet positif sur la coopération. Toutefois, les mécanismes de sanction peuvent également générer des externalités négatives fortes sur les gains. Dans quelle mesure l’introduction de menaces non crédibles est-elle en mesure d’impacter positivement la coopération sans engendrer ces externalités négatives? Afin de répondre à cette question, nous avons réalisé une expérience dans laquelle les agents ont la possibilité d’annoncer combien ils seraient prêts à sanctionner les autres membres de leur groupe pour tous les montants possibles de contribution. Nous observons qu’introduire cette étape de menace a un effet positif sur la coopération. Toutefois, l’efficience en termes de gain n’est pas améliorée à long terme. La possibilité de sanctionner ceux qui punissent moins que ce qu’ils ont annoncé conduit les agents à réduire le niveau de menace et celui de la coopération.
6. Strategically planned versus spontaneous behavior
In this experiment, we observe strategically planned behavior. We have to take into account that it does not necessarily fully reflect spontaneous behavior. From experiments on dynamic duopoly situations (Keser 1992) we have some evidence that strategically planned and spontaneous behavior are qualitatively similar, but differ quantitatively. In the public good situation, qualitatively, the reciprocity aspect prevails both in spontaneous and strategically planned behavior. Keser and van Winden (2000), for example, give some evidence for reciprocity in spontaneous public good experiments. 8 Reciprocity is defined there in a qualitative way. If a subject intends to change his decision from one period to the next, he changes it in the direction of the other group members’ average contribution in the previous period. This means that he increases his contribution if it was below the average of the others and decreases his contribution if it was above the average. Applying this definition of reciprocity to the data of Keser (1996), subjects significantly tend to behave in a reciprocal manner (two-sided binomial test, 1 percent level).
The results of the literature review on egress times from single-family houses are provided in reference . Data related to egress time from single-family houses is very limited. Currently it is only possible to provide rough estimates of evacuation time, which should be used with great care. Based on the analysis of current literature and limited scientific information, the overall evacuation time (starting from smoke alarm activation) for a typical two-story single-family house is estimated to be 60 s for the best-case scenario and 660 s for the worst-case scenario. The large difference in the estimated evacuation time between the best-case scenario and the worst-case scenario is mainly due to the variation in the pre-movement time. The time spent in pre-movement activities before deciding to leave the house can lengthen egress times and may result in
hollow cores, low density particles with controlled surface aspect, highly porous networks, hierarchical structures with nanoparticles sub-units) by manipulating operating and formulation parameters [10, 13].
The prediction of particles structure (physical spatial location of components within the particles) and morpholo- gies is a major scientific challenge regarding the spray drying process . The drying process involves simultaneous heat and mass transfer, phase transition, flow and mechanical instability (during solid formation). The fast drying complicates the sampling and recording of physical phenomena taking place in each droplet during drying. To better understand the mechanisms of particle formation and thus to support and clarify the design of particles with various structures and morphologies, experimental studies are usually carried out at two di fferent study scales : the spray scale and the droplet scale.