Search

Dans le roman Préhistoire qu’il fait paraître en 1994, Éric Chevillard s’emploie à dépeindre une grotte fictive ornée de nombreuses peintures et gravures rupestres. Volontiers parodique, la description qu’en donne le narrateur paraît curieusement contaminée par son objet : elle vise à faire entendre la fossilisation discursive qui bien souvent obère la compréhension de l’ère paléolithique. Cette distanciation critique envers les discours trop convenus sur la préhistoire permet au romancier de promouvoir un regard original sur l’art pariétal, qui donnerait accès à une forme d’utopie antéhistorique où l’homme cohabiterait encore avec l’animal. Mais comme toujours chez Chevillard, la question de l’écriture n’est jamais très loin : en dernier ressort, peintures et sculptures permettent au romancier de s’interroger sur la manière dont le roman dans sa forme la plus contemporaine pourrait trouver dans un art plurimillénaire les conditions de son propre renouvellement. In his novel Préhistoire (Prehistoric Times), published in 1994, Éric Chevillard strives to depict a fictional cave adorned with numerous rock paintings and engravings. The description (intentionally a parody) provided by the narrator seems, strangely enough, to be contaminated by its own object; its aim is to reflect the discursive fossilisation which very often precludes our understanding of the Paleolithic age. This critical distancing from stereotyping discourses on prehistory allows Chevillard to promote a new perspective on cave art which could provide access to a form of ante-historical utopia where Man and Animal could still be coexisting. But as is usually the case with Chevillard, it is the reflection on writing which seems to be at stake here and, ultimately, paintings and engravings give the novelist an opportunity to examine the way in which the novel in its most contemporary form could find in an age-old art the conditions for its own renewal.

The plastic deformation of Polybutylene terephthalate (PBT) is investigated at three temperatures (120$^\circ$C, 150$^\circ$C, 180$^\circ$C) representative of the span between glass transition, $T_g \approx 55^\circ$C and melting $T_m \approx 225^\circ$C temperatures. The mechanisms of tensile deformation are analyzed as a function of the true strain using a combination of temperature-controlled tensile experiments coupled with 2D digital image correlation and synchrotron sourced wide angle (WAXS) and small angle (SAXS) X-ray scattering the amorphous and crystalline regions causing the transition between polymorphs, respectively from the isotropic amorphous phase to a smectic phase and from the $\alpha$ crystalline phase to the $\beta$ phase.

A study of methodological nature demonstrates the efficiency of a probation test allowing for the intrinsic character of a rheological constitutive law to be assessed. Such a law is considered here for semicrystalline polymers exhibiting necking and for large deformation. In the framework of a law of behavior of $( \dot{\sigma },\sigma , \dot{\varepsilon },\varepsilon )$ , tensile experiments conducted at an imposed constant strain rate $\dot{\varepsilon }_{0}$ bring true stress responses, from which the constitutive (material) parameters can be identified from model-based metrology concepts. The same experiment repeated at various strain rates gives an access to the dependence of the nonelastic parameters on the strain rate. Then the intrinsic law is tested severely by considering a new set of experiments carried out for constant displacement rates of the grips. In that case the specimens show local strain rates that evolve strongly during the test (by a factor of 5–10). The parameter identification process requires the introduction of the exact realized input strain and strain-rate command into the model. Accounting for strain rate dependency additionally requires the knowledge of the preliminary identified strain rate dependence of the nonelastic constitutive parameters for good predictions of the experimental response directly. This is what is proven here. The conclusion speaks in favor of a possible upgrade of international standards for the mechanical characterization of polymers based on constant strain-rate tensile tests and properly applied model-based metrology.

La représentation que les romanciers donnent aujourd’hui du tourisme atteste la permanence d’un imaginaire savant. Celle-ci se manifeste selon des modalités variées – que l’auteur endosse la posture du voyageur érudit, qu’il pastiche la phraséologie savante de la documentation touristique, qu’il laisse ses personnages de touristes réinvestir comiquement le discours scientifique ou qu’il y recoure lui-même pour observer les habitus du voyageur, faisant du touriste un nouvel objet d’étude., The way contemporary novelists portray tourism attests to an enduring scholarly imagination. It appears in various ways: the author can endorse the posture of the erudite traveller, pastiche the learned phraseology of holiday brochures, allow the fictional tourists make comical use of the scientific discourse, or use it himself to observe the habitus of the traveller, making the tourist a new study object.

International audience

FFT-based solvers are increasingly used by many researcher groups interested in modelling the mechanical behavior associated to a heterogeneous microstructure. A development is reported here that concerns the viscoelastic behavior of composite structures generally studied experimentally through Dynamic Mechanical Analysis (DMA). A parallelized computation code developed with complex-valued quantities provides virtual DMA experiments directly in the frequency domain on a heterogeneous system described by a voxel grid of mechanical properties. The achieved precision and computation times are very good. An effort has been made to illustrate the application of such a virtual DMA tool through two examples from the literature: the modelling of glassy/amorphous systems at a small scale and the modelling of experimental data obtained in temperature sweeping mode by DMA on a particulate composite made of glass beads and a polystyrene matrix, at a larger scale. Both examples show how virtual DMA can contribute to question, analyze, and understand relaxation phenomena on either theoretical or experimental points of view.

This is an Open Review of the paper: S. André, J. Boisse, C. Noûs, An FFT solver used for virtual Dynamic Mechanical Analysis experiments: Application to a glassy/amorphous system and to a particulate composite, Journal of Theoretical, Computational and Applied Mechanics (2021). 10.46298/jtcam.6450

FFT-based solvers are increasingly used by many researcher groups interested in modelling the mechanical behavior associated to a heterogeneous microstructure. A development is reported here that concerns the viscoelastic behavior of composite structures generally studied experimentally through Dynamic Mechanical Analysis (DMA). A parallelized computation code developed under complex-valued quantities provides virtual DMA experiments directly in the frequency domain on a heterogenous system described by a voxel grid of mechanical properties. The achieved precision and computation times are very good. An effort has been made to show the application of such virtual DMA tool starting from two examples found in the literature: the modelling of glassy/amorphous systems at a small scale and the modelling of experimental data obtained in temperature sweeping mode by DMA on a particulate composite made of glass beads and a polystyrene matrix, at a larger scale. Both examples show how virtual DMA can contribute to question, analyze, understand relaxation phenomena either on the theoretical or experimental point of view.

A study of methodological nature demonstrates the efficiency of a probation test allowing for the intrinsic character of a rheological constitutive law to be assessed. Such a law is considered here for Semi-Crystalline Polymers exhibiting necking and for large deformation. In the framework of a (, ,,) behavior's law, tensile experiments conducted at an imposed constant strain rate 0 bring true stress responses from which constitutive (material) parameters can be identified from Model-Based Metrology concepts. The same experiment repeated at various strain rates gives then access to the dependence of the non-elastic parameters on the strain rate. Then the intrinsic law is tested severely by considering a new set of experiments carried out for constant displacement rates of the grips. In that case, the specimens show local strain rates which evolve strongly during the test (by a factor of 5-10 here). The parameter identification process requires then the introduction of the exact realized input strain and strain-rate command into the model. Accounting for strain rate dependency requires additionally the knowledge of the preliminary identified strain rate dependence of the non-elastic constitutive parameters for good predictions of the experimental response directly. This is what is proven here. The conclusion speaks in favor of a possible upgrade of international standards for the mechanical characterization of polymers based on constant strain-rate tensile tests and properly applied model-based metrology.

A study of methodological nature demonstrates the efficiency of a probation test allowing for the intrinsic character of a rheological constitutive law to be assessed. Such a law is considered here for Semi-Crystalline Polymers exhibiting necking and for large deformation. In the framework of a (, ,,) behavior's law, tensile experiments conducted at an imposed constant strain rate 0 bring true stress responses from which constitutive (material) parameters can be identified from Model-Based Metrology concepts. The same experiment repeated at various strain rates gives then access to the dependence of the non-elastic parameters on the strain rate. Then the intrinsic law is tested severely by considering a new set of experiments carried out for constant displacement rates of the grips. In that case, the specimens show local strain rates which evolve strongly during the test (by a factor of 5-10 here). The parameter identification process requires then the introduction of the exact realized input strain and strain-rate command into the model. Accounting for strain rate dependency requires additionally the knowledge of the preliminary identified strain rate dependence of the non-elastic constitutive parameters for good predictions of the experimental response directly. This is what is proven here. The conclusion speaks in favor of a possible upgrade of international standards for the mechanical characterization of polymers based on constant strain-rate tensile tests and properly applied model-based metrology.

International audience; To improve the lifetime of proton-exchange membrane (PEM) fuel cells, it is necessary to provide a better understanding of the degradation mechanisms of the perfluorosulfonic acid (PFSA) membranes during fuel cell operation. Despite quantities of work focusing independently on chemical or mechanical degradation, only a few concerned the effect of both combined. The purpose of this study is to analyze the effects of conjoint chemical and mechanical stress on PFSA membranes via an ex-situ approach. First, an investigation of the effects of chemical degradation by radical attacks (i.e. exposure to Fenton reagents) on PFSA membranes was carried out. The results confirm that the chemical decomposition of PFSA membranes is significantly influenced by the concentration of Fenton's reagents, both chemically and morphologically. Second, a custom-made device was developed to examine the impact of coupled chemical and mechanical degradations. The initial results show that fully hydrated membranes seem to withstand severe sinusoidal constraints as no crack formed. However, the application of cyclic compression resulted in accelerated chemical decomposition of PFSA membranes. The results also demonstrate that some microstructural changes can appear and lead to a slight increase in the hydrogen crossover that can be detected before it impacts the cell performances.

En raison de son caractère supposément prévisible et stéréotypé, le tourisme a longtemps été relégué aux confins de la recherche littéraire : il n’existerait de voyage authentique qu’en marge des réseaux organisés. Cette conviction est si profondément enracinée que très peu d’ouvrages se proposent d’examiner l’influence qu’exerce aujourd’hui le tourisme sur la littérature. Cette frilosité apparaît étonnante tant elle contraste avec l’abondance des travaux menés dans le champ des sciences huma...

L’utilisation d’additifs conservateurs est souvent nécessaire pour assurer la sécurité microbiologique des produits carnés réfrigérés faiblement acides. Le projet ANR BLac HP (2014-2019) a étudié une nouvelle stratégie de stabilisation des produits carnés réfrigérés pour assurer le contrôle des flores indésirables à la fois végétatives et sporulées. Grâce à une approche pluridisciplinaire, les travaux ont montré que la combinaison de la biopréservation par des bactéries lactiques et d’un traitement hautes pressions permettait d’assurer la qualité microbiologique de dés de jambon cuits à teneur réduite en nitrite pendant toute leur durée de vie. Le traitement permet de plus une qualité sensorielle optimale sans impact environnemental supplémentaire par rapport au procédé conventionnel. Mots-clés: spores, jambon, nitrites.

Following the routes opened by the resort to spectral solvers applied on real composite microstructures to analyse the homogenization problem in elasticity, we extended a FFT approach implemented in the CRAFT solver [1] to viscoelastic materials. The idea is to propose a virtual Dynamical Mechanical Analysis experiment applied on heterogeneous microstructures. DMA performs a frequency analysis of the transfer function of the material by applying a sinusoidal harmonic steady-state regime. The transfer function (modulus, relaxation, compliance... quantities) is complex with classical storage and loss components (real and imaginary parts) [2]. It offers a full frequency characterization of the material constitutive law which can be applied afterwards in all cases of temporal excitations. CRAFT code and its central Lippmann-Schwinger equation are then solved in complex variables. Examples will be given of various microstructures made of two individual viscoelastic constituents assumed to behave according to a standard 3-parameter Voigt rheological model (spring connected in series with a Voigt unit [2]). As already shown [3], the key resulting effect on the homogenized effective material is the appearance of an additional fading memory term i.e. of a transfer function with broadened pectrum of relaxation times. Following this fact and connections established with fractional rheological models, we willshow that a very efficient effective model can describe the mesoscopic behaviour of a great variety of microstructures.REFERENCES : [1] H. Moulinec, P. Suquet, A numerical method for computing the overall response ofnonlinear composites with complex microstructure, Comput. Methods Appl. Mech.Engrg., 157, 69-94, 1998.[2] N.W. Tschoegl, The Phenomenological Theory of Linear Viscoelastic Behavior, AnIntroduction, Springer Verlag, 1989.[3] R. Brenner, P. Suquet, Overall response of viscoelastic composites and polycrystals:exact asymptotic relations and approximate estimates. Int. J. Sol. Struct., 50(10), 1824-1838, 2013.[4] S. Andre, Y. Meshaka, C.Cunat, Rheological constitutive equation of solids: a linkbetween models based on irreversible thermodynamics and on fractional order derivativeequations, Rheologica Acta, 42, 500-515.

Colloque avec actes et comité de lecture. Internationale.; International audience; We show in this study the high benefits that can be retrieved from the SAXS technique (Small Angle X-ray Scattering) performed with synchrotron lightsource (beamline cSAXS at PSI-SLS) to follow the initiation and the development of a necking (plastic instability) phenomenon underwent by a semicrystalline polymer under tension. High sensitivity and fast detectors used at this beamline as well as motorized fast displacement systems enable to realize 1D and even 2D scans of the specimen during the test. The integration time (33ms) and read out time (3ms) make a spatial resolution of the scanning of 360microm at the displacement rate of 10mm/s ensured by the displacement OWIS stages. At the same time, the tensile machine proceeds with a displacement rate of 20mm/s which means a negligible displacement of the material points on the specimen during the scan. The methodology to handle the data is quite tedious also not complicated. In order to study quantitatively the microstructure evolution during tension for different material points, a precise calibration procedure has been set up thanks to 3-D stereo Digital Image Correlation (DIC system ARAMIS from GOM instruments). The same tensile tests have been performed under DIC to provide the relationship between the running time of the test, the material points coordinates in the reference frame, their respective eulerian positions according to time and their measured local true strain. This gives rise to the following Fig.1 linking all of these variables. The points give the position of the recorded scans along the specimen (Z screaning). The red lines figure out the trajectory of initial material points and allow to find the patterns taken for a same material points at different times. The blue curves are isostrain curves and allow to find all patterns corresponding to a given strain, although for different material points. This figure is the key to be able now to determine whether or not the microstructure state is only governed by the true strain. As a result of the [0.017-1] nm-1 q-range of our experiments, the microstructure is probed at the length scale of scatterers ranging approximately in the 10-350 nm. Its evolution is monitored through a quantitative observable raised from the SAXS pattern analysis. It is an anisotropy index [1] defined as where correspond to the intensities measured along the horizontal and vertical axis of the image frames, respectively the tensile and transverse directions. The local anisotropy is then measured at different locations for different true strain values ranging from 0 to 2 (about 700% of extension ratio). We cover the range of viscoelasticity followed by a long stage of plastic development and a plastic propagation accompanying the hardening rubbery state. The anisotropy index measured for different material points as a function of true strain produces identical curves (within the uncertainty of the measurements). This new result proves that the microstructure is fully governed by the sole strain. Such results enable to consider that this observable gives a true signature of the kinetics of internal reorganization during the tensile deformation of the polymer. It is worthwhile to mention that next efforts made in the modeling of semicrystalline polymer should pretend to recover such signature. References [1] L. Farge, S. André, F. Meneau, J. Dillet, C. Cunat, A common multiscale feature of the deformation mechanisms of a semi-crystalline polymer, Macromolecules, 46(24), (2013), 9659-9668.

International audience; [Technical Session 7 – Food Processing Technologies]Introduction: The high demand for minimally processed food makes high pressure processing (HPP) one of the most promising non-thermal technologies for food application. While HPP efficiently inactivates vegetative bacteria, bacterial spores show strong resistance, especially at mild temperatures. To ensure spore inactivation in food matrices, the addition of other hurdle(s), such as mild heat or antimicrobial agents, is necessary.Purpose: HPP in combination with nisin was investigated as a non-thermal method for the inactivation of pathogenic and thermoresistant bacterial spores in food matrices.Methods: Six bacterial strains were studied with regard to the diversity of their origins and properties: Bacillus pumilus, Bacillus sporothermodurans, Bacillus licheniformis, Bacillus weihenstephanensis, Bacillus subtilis and Clostridium sp. (botulinum type E-like). Spores were treated in a buffer, skim milk or a liquid medium simulating cooked ham. Pressure levels ranging from 200 MPa to 600 MPa were applied for 10 min at 20°C or 50°C. Nisin was added during and/or after HPP to a final concentrations of 50 or 20 UI/mL.Results: While no significant reduction of spore cultivability was observed at any pressure at 20 °C, the addition of nisin at low concentration (ten times lower than the legal concentration) during and after HPP treatment induced a highly synergistic effect on Bacillus spp. inactivation, with spore count below the detection limit (inactivation > 6 log/mL). Moreover, spores remained sensitive to nisin up to 6h after HPP.Significance: The food industry usually pressurizes foods at room temperature, resulting in, only, inactivation of vegetative cells. The present work shows that combining HPP with nisin can lead to a synergistic Bacillus spp. spore inactivation, even after treatments at 20°C. The addition of nisin in foods before their pressurization can, therefore, be an efficient way to ensure the inactivation of bacterial spores.

This thesis endeavours to examine the representation that the contemporary novel imparts to tourism. It draws on a corpus of novels issued between 1990 and 2010, involving writers as diverse as Éric Chevillard, Jean Echenoz, Mathias Énard, Michel Houellebecq, Lydie Salvayre, Olivier Rolin or Jean-Philippe Toussaint. Each of these writers seeks to outwit often prescriptive and stereotyped views. These authors shed light on the tourist’s contradictory aspirations and the way this unexpectedly complex character, whose behaviour has been inherited from ancient historical and literary paradigms, interacts. The contemporary novel also takes over tourism as a line of business– a heterotopia, as Michel Foucault understood it– akin to a repertoire of forms, contributing to its aesthetic renewal. Lastly, the novel interrogates this touristic interface device, which, positioning itself between the traveler and the outer world, jeopardizes the understanding of it. Hence, the return to transitive writing is thwarted by a reality that falls away under its own representation. Paradoxically enough, while consenting to confront that medium which tourism represents, and playing upon and against the stereotypes it conveys, the novel manages to rekindle its ties with an original journey., Cette thèse s’efforce d’examiner la représentation que le roman contemporain donne du tourisme. Elle s’appuie sur un corpus de romans parus entre 1990 et 2010 mêlant des auteurs aussi divers qu’Éric Chevillard, Jean Echenoz, Mathias Énard, Michel Houellebecq, Lydie Salvayre, Olivier Rolin ou Jean-Philippe Toussaint. Chacun de ces écrivains s’emploie à déjouer un discours au caractère souvent prescriptif et stéréotypé. Ces auteurs donnent à voir les aspirations contradictoires du touriste et la manière dont interagit ce personnage étonnamment complexe, au comportement hérité de paradigmes historiques et littéraires anciens. Le roman contemporain investit également le tourisme en tant que secteur d’activité– une hétérotopie au sens où l’entendait Michel Foucault – assimilable à un répertoire de formes contribuant à son renouvellement esthétique. Enfin, le roman interroge cette interface touristique, qui, s’intercalant entre le voyageur et le mode extérieur, en hypothèque la compréhension : le retour à une écriture transitive se trouve contrarié par un réel qui se dérobe sous sa propre représentation : paradoxalement, c’est en consentant à affronter ce medium que constitue le tourisme et en jouant ou en déjouant les stéréotypes dont il est porteur que le roman parvient à renouer avec un voyage original.

National audience

International audience; This study tests the hypothesis of vulnerability in health and social care professionals dealing with difficult adolescents. This vulnerability appears to be underpinned by an occupational identity crisis that seems to diminish the ability of these professionals to recognize the suffering of these adolescents. A questionnaire was developed and then distributed during a network day bringing together members of various institutions and bodies working with difficult adolescents. Ninety-three professionals responded. Occupational identity weaknesses were identified: inadequate basic training, experiences of solitude, feelings of powerlessness and exposure, inadequate personal and institutional resources. Actors involved express their need for inter-institutional and inter-sectoral network but find it uneasy to implement. Some changes can be recommended to reduce this occupational identity crisis: increased efforts towards continuing training, development of possibilities of reflection within institutions, and more structured partnerships and actions.

International audience; Sterilization is the most relevant technique to guaranty safety of shelf-stable food products at ambient temperature. However, these thermal processes are often optimised to microbiological aspect and consequently are not without consequences on quality. Only few studies are focussed on the simultaneous management of these two aspects. Ascorbic acid is of interest due to its vulnerability and health benefits. Its degradation at sterilization temperature (> 100 °C) is poorly documented. The aim of this work is to model thermal processes in a risk/benefit approach, taking in account the nutritional aspect. Its final objective is to design new thermal processes which will be efficient to inactivate heat-resistant microorganisms, but not too drastic in order to maintain the maximum quality. Using a new instrumented reactor (thermoresistometer Mastia®), the behaviors of ascorbic acid food model solution at pH = 3.5, in aerobic and anaerobic conditions, was measured. The obtained data have shown that degradation of ascorbic acid does not follow classical kinetics in conditions of appertization, it follows 0.5-order kinetics in aerobic conditions and zero-order kinetics in anaerobic conditions.

28 pages, 13 figures, 2 test cases; The Gauss Newton method of least squares minimization for non-linear parameter estimation is revisited for parameters with different physical units. A normalization of each parameter with respect to its nominal value, that is at iteration number k-1, is implemented, which leads to a linear tangent model. This model uses the sensitivity matrix composed of the scaled sensitivity coefficients. It is decomposed under a singular values form and the covariance matrix of iterate number k is calculated. When the scaled standard deviation of one parameter estimates takes a too large value, inversion of the tangent model becomes ill-posed. Regularization is made by giving the smallest singular values infinite levels, which allows keeping the total number of parameters to be estimated unchanged : this regularization leads to a better conditioned problem in the following iterations until convergence of the residuals is reached. The corrresponding algorithm is tested in the case of two very ill posed-examples. This type of estimation performs very well when compared to the Lebenverg Marquardt algorithm.

Microbial contaminants of safety concern represent most of time, in canned food, an industrial risk which is well mastered. However, the spoilage flora, due to its high heat resistance, is responsible for major economic losses. Nevertheless, these bacteria remained poorly characterized. Based on the works realized during last 10 years within the EMaiRIT'S unit of microbiology of the CTCPA (expertise unit of the French Technical Center of the Preservation of Food, focused on Management of Industrial Risk liked to Heat Resistant Spores), the main objective of this thesis were: i) to identify and to characterize, with the aim of its later control, the spoilage spore forming bacteria florae ii) to identify the origin of these florae in canning factories and finally iii) to determine ways of control.For that purpose, a current inventory of spore forming bacteria in spoiled canned food was made with the cooperation of 122 canning factories over more than 10 years in France. This characterization of the spoilage species allowed the elaboration of a molecular biology tool (SporeTraQTM) for quick identification of these germs or their detection within a complex population. In parallel, the improvement of the knowledge about the heat resistance of these species, main characteristic of the spores, was led. In addition, the chemical resistance of spores was investigated. When identified, we tried to localize these spores on canning factories lines, with several sampling plans, on various vegetables. At the end, the specific spore forming bacteria related to the industrial canning process was identified, characterized and localized, allowing to improve the microbial risk control either by a more efficient cleaning, and through optimized process schedules. Furthermore, this work was driven within a benefic / risk approach representing the future of the food-processing evolution with improvement of the nutritional quality and the preservation of the sanitary control.This thesis leans on 5 publications of rank A.; Si les flores contaminantes représentent la plupart du temps, dans les conserves, un risque industriel aujourd'hui maitrisé, la flore d'altération, de par sa résistance importante à la température, continue à constituer une cause de pertes économiques majeures. Pourtant cette dernière restait cependant peu caractérisée. En s'appuyant sur les travaux réalisés ces dernières années au sein de l'unité de microbiologie EMaiRIT'S du CTCPA (unité d'Expertise dans la Maitrise du Risque Industriel en Thermorésistants Sporulés du Centre Technique de la Conservation des Produits Agricoles), les principaux objectifs de cette thèse ont été (i) d'identifier et caractériser, en vue de sa maitrise ultérieure, la flore d'altération sporulante (ii) d'identifier l'origine de ces flores dans les conserveries et enfin (iii) de déterminer des moyens de maitrise.Pour cela, un état des lieux des bactéries sporulées d'altération des conserves a été effectué avec la collaboration de 122 conserveries sur plus de 10 ans en France. Cette caractérisation des espèces altérantes a permis l'élaboration d'un outil de biologie moléculaire (SporeTraQTM) afin d'identifier rapidement ces germes ou de pouvoir les détecter au sein d'une population complexe. En parallèle, l'amélioration de la connaissance de la thermorésistance de ces espèces, principale caractéristique de la flore sporulante, a été menée. A ce paramètre, il a été associé une relation avec la chimio résistance des spores. Identifiée, nous avons cherché à localiser cette flore d'altération au sein des usines à l'aide de plusieurs campagnes de prélèvements sur différents légumes. Au final, la flore spécifique du procédé de fabrication des conserves a été identifiée, caractérisée et localisée en vue d'améliorer la maitrise du risque microbien soit par une maitrise des contaminations et/ou un nettoyage plus performant (localisation au niveau d'étapes unitaires, efficacité de molécules sporicides) soir par un barème optimisé (en relation avec la thermorésistance). De plus, ce travail a été conduit au sein d'une approche bénéfice/risque représentant le futur de l'évolution des procédés agro-alimentaires associant amélioration de la qualité nutritionnelle et maintien de la maitrise sanitaire. Cette thèse s'appuie sur 5 publications de rang A.

International audience; By means of time-resolved small-angle X-ray scattering, we developed an analysis methodology to assess the void volume fraction ϕv in high-density polyethylene (HDPE) during tensile testing. The specimens were first drawn up to different imposed strains, and subsequently were subjected to stress unloading and strain recovery stages. During the loading stage, ϕv progressively increased with the strain level, starting from a well-defined onset strain prior to the yield point. In particular, ϕv reached a maximum of 8.75 vol% for a strain of 12.5% in the case of a HDPE grade with a molecular weight of 105 000 g mol−1. Stress unloading and strain recovery caused a decrease in ϕv attained at the end of the loading stage. For a HDPE grade with a molecular weight of 55 000 g mol−1, ϕv was more important during the loading stage and the decrease in ϕv was less marked during the stress unloading stage when compared to the HDPE with molecular weight of 105 000 g mol−1. The residual and reversible components of void volume fraction were revealed.

International audience; This paper is devoted to a theoretical and numerical study of different ways of calculating the Fourier transform of a noisy signal where the boundary conditions at the lateral boundaries of the measurement interval are not precisely known. This happens in different characterization problems where infrared camera is used for temperature measurements. In order to overcome this difficulty, the interval where the Fourier transform (its support) is supposed to be larger than the measurement domain is defined. Thus, this virtual interval larger than the measurement interval is used. We show that regularization by truncated singular value decomposition is able to yield good estimates to this very ill-posed inverse problem.

National audience; La caractérisation thermomécanique par imagerie infrarouge nécessite un traitement inverse du champ de température afin de reconstruire les sources de la chaleur volumique. Par des mesures cinématiques (déplacements-vitesses), le phénomène d'advection thermique peut-ˆ etre pris en compte pour l'inversion. Nous proposons ici une méthode de reconstruction de source 1D (´ eprouvettesélancéeseprouvettes´eprouvettesélancées) ` a l'aide d'une base de Branche. Les vitesses locales de déformation lors des instabilités plastiques peu-ventêtreventˆventêtre importantes pour un polymère thermoplastique et sont maintenant accessibles par corrélation d'images. On présentra leprobì eme de Branche généralisé, puis la technique de régularisation utilisée : 1)Troncature des modes 2)Méthodes des temps futurs. L'algorithme conduitàconduit`conduità une inversion rapide en temps de calcul et ses performances seront analysées sur un cas-test pour lequel une source stationnaire en temps mais présentant des discontinuités sera considérée. Nomenclature T température, K k conductivité thermique, W/m/K c chaleur volumique, J/m 3 /K v 0 vitesse d'advection constante, m/s h 1 , h 2 coefficient d'´ echange, W/m 2 /K q source thermique, W/m 3 v vitesse d'advection variable, m/s

Caractérisation de la diversité génétique de [i]Moorella[/i] et [i]Geobacillus[/i] par M13-PCR. 9. Congrès National de la Société Française de Microbiologie

International audience

National audience

International audience; L'objet de cet article est une présentation d'un cas clinique original dont les symptômes correspondent à une pathologie très particulière du fait de sa rareté, de son expression symptomatique et de son éthiopathogénie non élucidée, qu'est le syndrome de Kleine-Levin. Il s'agit d'un jeune patient âgé de 15 ans qui a présenté une modification brutale du comportement, en rupture avec l'état antérieur, avec une hypersomnie au premier plan, au décours d'une angine concomitante avec un choc émotionnel. Nous avons assisté à une régression spontanée et totale de la symptomatologie au bout de 12 jours, exception faite de la persistance d'une amnésie lacunaire. Quatre mois plus tard, au décours d'une ivresse aiguë, le patient a présenté un nouvel épisode similaire. Après une présentation sous forme d'une vignette clinique, nous aborderons la situation sous un angle plus psychopathologique, en nous posant la question d'un profil psychologique favorisant et des liens éventuels avec les troubles bipolaires.

With the strengthening of corporate social responsibility, performance evaluation within companies needs to be revised. In this context, our research aims to validate the interest of the Multicriteria Decision Analysis methodologies (MCDA). We propose a method called EPISSURE which allows non financial performance evaluation thanks to synthesis indicators, which are built in a four hierarchical levels and computed with MCDA tools. These indicators are implemented thanks a formalized process called “framed dialog”. The purpose of this “framed dialog” is to build a common vision about performance evaluation for all the shareholders. In order to validate EPISSURE, we conducted eight fields’ studies about environmental and sponsorship performance evaluation. EPISSURE is still working on four of these eight studies. Even if several limits have been pointed up, feedbacks seem to validate that EPISSURE could be considered as an added value in order to evaluate non financial performance.

International audience; Les changements économiques et sociaux ont été considérables au cours des trente dernières années. On constate le désengagement de l'Etat dans le lien d'alliance, une modification importante de la conjugalité privatisée et précarisée, les rapports de genre transformés, de nouvelles conditions d'avènement de l'enfant dans le couple – enfant programmé et privé - et un bouleversement de la parentalité dont les repères juridiques, symboliques et les pratiques ont beaucoup évolué. Ces nouvelles coordonnées de la famille, centrées maintenant sur le consensus à la place de l'autorité pour organiser les rapports entre ses membres, sur l'hédonisme en lieu et place du devoir comme valeur centrale, avec un enfant du désir, reconnu d'emblée dans son individualité - « le bébé est une personne » -, enfant fait « pour soi et pour lui », élevé dans un environnement où la place croissante des médias peut les faire comparer à un « troisième parent », conduisent à une structuration de la psyché de l'enfant qui n'est plus sur le modèle névrotique. En s'appuyant sur les travaux d'anthropologues, nous proposons l'hypothèse d'une nouvelle personnalité de base, traduction des nouveaux repères de la société et de la famille et conséquences des nouvelles pratiques d'éducation des enfants, qui viendrait remplacer la personnalité de base névrotico-normale qui a dominé au cours de la première moitié du XXe siècle. Cette personnalité de base, que nous proposons d'appeler « narcissico-hédoniste », présente des caractéristiques spécifiques, avec une faiblesse des intériorisations, un Surmoi peu efficace, une absence presque totale de culpabilité, un Idéal du moi peu socialisé, évoquant plutôt le Moi idéal de la première enfance, et enfin, une difficulté à « être », à s'éprouver comme un sujet libre. Il en résulte une fragilité narcissique conduisant le sujet à une plus grande dépendance à l'égard des objets externes, une intolérance à la frustration, des difficultés à supporter le délai dans la réalisation des visées pulsionnelles et une recherche de perception et de sensations exacerbée. Le rapport au temps est également modifié, avec un investissement privilégié du présent, un estompage du temps historique. A cette personnalité de base, associée à une nouvelle subjectivité, correspondent, dans les achoppements du développement, des pathologies fréquentes de l'agir, des conduites de dépendance, et des troubles de l'attachement. Cette nouvelle configuration, associant à une nouvelle personnalité de base, des pathologies spécifiques, implique de réinterroger nos pratiques de soins afin de les adapter aux nouveaux patients.

Colloque avec actes et comité de lecture. Internationale.; International audience; Nous réalisons un essai mécanique piloté par Vidéotraction avec enregistrement simultané des cartes de température sur l'éprouvette via une caméra infrarouge haute définition. Un traitement d'analyse d'image permet de reconstruire les sources thermiques au centre de l'éprouvette à partir de l'équation de la chaleur. L'analyse thermodynamique explicite la nature des diverses contributions responsables des sources : (i) la thermoélasticité, (ii) la variation d'entropie due aux évolutions micro-structurales et (iii) la dissipation intrinsèque provoquée par ces réorganisations. Nous développons une modélisation selon la démarche DNLR(Distribution of Non Linear Relaxations) qui intègre ces couplages via la résolution simultanée de trois familles d'équations d'état, l'une d'elle reflétant l'évolution entropique (équation de la chaleur), une autre relatant le comportement mécanique couplé à la fois à la thermique et à la micro-structure et une troisième reliant les potentiels chimiques aux sollicitations imposées. La confrontation avec l'expérience est d'ores et déjà tout à fait satisfaisante.

Within a firm, the measure of performance must be relevant at each level of management. For the financial field, it is “quite easy” to set objectives at each level. This possibility comes from the fact that financial indicators can be easily added from one level to another. Concerning the environmental performance, these additions are, most of the time, not as meaningful as targeted. However, with the strengthening of the sustainable development concept, the need for an evaluation of synthesis exists and appears more and more meaningful, especially for the guiding of the environmental performance. Nonetheless, the evaluation of an environmental performance of synthesis raises several kind of difficulties: methodological, philosophical and managerial. The aims for the research paper are: - to propose a methodology to assess the environmental performance thanks a synthesis indicator. This indicator is evaluated on an ordinal scale and computed with an ELECTRE TRI methodology. As a validation case, we implemented some synthesis indicators in the refineries of the Total company - to present the capacity and the limits of the method to o formalize a synthesis performance which is meaningful for the stakeholders o allow the participation of the local stakeholders o take into account the local specificities of the site. - to highlight the methodological aspects to be integrated in order to implement such synthesis indicators.

With the strengthening of corporate social responsibility, the need for an evaluation of the environmental performance exists and appears more and more meaningful for the companies. This research paper proposes an evaluation “process & tool” which has been experimentally implemented within the multinational energy company Total. This evaluation is based on synthesis indicator build thanks a dialogue between the stakeholders. The research paper aims to show the added value of this dialogue and why it is necessary to implement an efficient environmental management tool.

Not available, La méthode flash est étendue à la gamme de températures 20°C-600°C. Appliquée aux milieux semi-transparents (M.S.T.), et couplé à une étude théorique du transfert combiné conduction/rayonnement, elle permet d'accéder directement à la mesure de la diffusivité phonique des verres. Pour cela, le rôle des conditions aux limites radiatives (noires ou réfléchissantes), de l'épaisseur de l'échantillon, du degré de semi-transparence du matériau (coefficient d'absorption) a été mis en évidence. Une étude expérimentale portant sur cinq verres à teneur en Fe2O3 différente, a confirmé les prédictions théoriques établies dans le cas du milieu gris. La prise en compte de la dépendance spectrale du coefficient d'absorption, par un modèle multi-bandes (milieu non-gris), reste sans influence sur la mesure de diffusivité phonique dans les cas indiqués. Nous proposons finalement une nouvelle expression de la conductivité phonique des verres flottés en fonction de la température

Orientadores: Luiz Benedicto Lacerda Orlandi, Anne Sauvagnargues Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas Resumo: A Geofilosofia é um conceito tardio na obra de Deleuze e Guattari e, embora se aplique ao último livro em parceria, Qu'est-ce que la Philosophie ?, trata-se de uma noção que envolve suas principais criações conceituais, circunscrevendo o período de Capitalisme et schizophrénie, mas dialogando com noções e momentos distintos da obra dos autores. Sob a rubrica da noção, a filosofia consagra a conexão de um plano de imanência absoluto derivado de um meio imanente e social que constitui a conjunção de relações variáveis entre o território e a terra. Assim, o ato de pensar não gravita sob a órbita das categorias sujeito e objeto, mas concerne a um meio intensivo e contingente, que, compondo uma ambiência de circunstâncias externas, demarca um campo de conexões e fronteiras de relações múltiplas e devires que contornam o molar e o molecular, estabelecendo um regime de troca, captura e sobrecodificação dos códigos. Nesse traçado, o pensamento e os conceitos invocam um "fora", um devir molecular, devires animais e imperceptíveis que povoam o território e os agenciamentos, perfilham conexões, ramificações heterogêneas e rizomáticas que seguem por linhas intensivas, conjurando forças e movimentos da terra que operam por movimentos diagramáticos, geodésia e desterritorialização. Configura-se, com efeito, uma cartografia dos deslocamentos, direções e trajetos que circunscreve o mapa de uma geografia agitada por linhas de fuga, longitudes e latitudes, sendo essas, portanto, as condições do plano de imanência absoluto do pensamento, de sua desterritorialização e reterritorialização Abstract: Geophilosophy is a lag concept in Deleuze and Guattari's work, and besides it can be applied at the last book in partnership Qu'est-ce que la Philosophie?, it is a notion that involves their main conceptual creations, circumscribing the period of Capitalisme et schizophrénie, but in dialogue with distincts notions and moments of both autors work. Under the heading of the notion, philosophy consecrates the conexion of an absolut immanence plan derivative of a social and immanent environment that constitutes the conjunction of variable relations between the territory and the earth. This way, the act of thinking doesn't gravitate in the orbit of the categories of subject and object, but concerns to a intensive and contingent environment, that, setting an ambience of external circunstances, delimits a field of conexions and borders, of multiple relations and becomings that skirts the molar and the molecular, establishing a system of change, capture and overcoding of the codes. In this route, the thought and the concepts invocate an "outside", a molecular becoming, animal and inconspicuous becomings that settle the territory and the assemblages, profiling conexions, heterogeneous and rhizomatic ramifications that follow by intensive lines, conjuring forces and movements of earth that operates by diagrammatic movements, geodey and deterritorialization. Setting up, in effect, a cartography of displacements, directions and pathways that circumscribes the map of a geography agitated by creepage, longitudes and latitudes, being these, by the way, the conditions of the absolut immanence plan of thinking, of its deterritorialization and reterritorialization Doutorado Filosofia Doutor em Filosofia

Outgoing