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International audience; Additive manufacturing techniques based on liquid resins, such as digital light processing (DLP), demonstrate higher resolution and accuracy than other printing techniques, but their applications have been hindered by the limited materials selection. Overall, there have been numerous successes in printing acrylic-epoxy resins but the final parts generally suffer from relatively poor mechanical properties. In this study, hybrid printable formulations that are based on acrylic-epoxy resins and ceramic filler are introduced and their printability on DLP machines is demonstrated. Here, we present an ultraviolet (UV) printed acrylic-epoxy with high Young modulus via a two-stage curing approach. Herein, different experiments are used to investigate the evolution of the materials properties during the post-process. Indeed, we conduct experiments to characterize the physico-chemical features and the evolution of mechanical properties before and after post-process. Finally we report the preparation of polymeric rapid tooling inserts with tailored mechanical and physical properties, which were used as injection molding cavities for prototyping and low volume production.

Skin irritation is a key human health endpoint assessed by in vitro and in vivo methods. The OECD TG 404 guideline (in vivo) is based on erythema and oedema translated semi-quantitatively into Draize scores, providing hazard statements for substance classification following EUCLP/UNGHS criteria. Draize scores require quantitation from subjective in vivo observations, to obtain a scoring index, the Primary Irritation Index (PII). However, it is not recognised under REACH due to translating difficulties, notably the cut-off limit for classification and non-inclusion of corrosive effects. The aim of this study was to determine if classification can be driven by just one of the observed effects, erythema only, to create a Simplified Irritation Index (SII

International audience; To be able to predict the throughput of a single-screw extruder or the metering time of an injection moulding machine for a given screw geometry, set of processing conditions and polymeric material is important both for practical and designing purposes. The model is based on viewing the entire screw simply as a pump, conveying a solid and a molten fraction. The evolution of the solid fraction is the essence of the plastication process, but under a particular hypothesis on solid bed acceleration, its influence on the throughput is nil. This allows getting a good estimate on the throughput and pressure development along the screw. Calculations are compared to a large set of experiments available from the literature. Consistent agreement with these published results is obtained, both for throughput and pressure along the screw. The effect of the plasticating process on the throughput is non-existent if the plastication length is short, and more visible if the plastication length takes a good part of the screw length (for instance, at higher screw rotation frequency). This diminishes the throughput value and widens the pressure peak. The model also shows that the screw geometry is the most important parameter, followed by polymer rheology and processing conditions. Melting properties and length seem to intervene to a lesser extent. Finally, the model is used for screw design, highlighting the influence of the compression zone on throughput.

This paper shows how current projects for the detection and observation of forest fires and volcanic eruptions by means of constellations of Earth watching satellites present t ough challenges in terms of autonomous on-board mission management. After a presentation of the reference mission, we describe the operational constraints on the management of this mission, the resulting architectural choices we made, the need for an anytime planning module on-board each satellite, and the dynamic programming approach we chose. Then, we present some preliminary experimental results on realistic scenarios and the work which remains to be done to gel a completely satisfying system.

In order to investigate the effect of the particular structure of latex films on mechanical (stress-strain behaviour) and adhesion (measured by peeling) properties, this work compares these characteristics for latex films and corresponding “solution films”. Solution films were obtained by dissolving the latex film in an appropriate solvent and forming a new film by evaporating the solvent. In this way, the latex and solution films have exactly the same composition but different structures. Four different systems were studied, namely a homopolymer of 2-ethyl hexyl methacrylate, a copolymer of styrene and butyl acrylate, a copolymer of butyl acrylate with a zwitterionic monomer, and, finally, an ethyl acrylate-methyl methacrylate copolymer partially grafted onto a hydrophilic polyester. It was shown that latex films have Young's moduli systematically higher than the corresponding solution films. This is due to the fact that the hydrophilic shells of the latex particles form a continuous phase in the latex film which increases the modulus thanks to polar interactions. Modeling was possible using an appropriate equation (Palierne's Model) which allowed the determination of the modulus and volume fraction of the shell phase, without adjustable parameter. On the other hand, adhesion energy for latex films is always smaller than for solution films. This is interpreted in terms of structure of the film-support interface and interface and dissipative processes within the bulk of the film.

The aim of the work presented in this article was to investigate the role of surfactants on adhesion properties of latex films. Several polymer/surfactant/support systems were used. Polymers were poly(2-ethyl hexyl methacrylate) or a methyl methacrylate/ethyl acrylate copolymer partially grafted onto a hydrophilic polyester. Surfactants were sodium dodecyl sulfate (SDS), hexadecyl pyridinium chloride (HPCI), or ethoxylated nonyl phenol containing 10 or 30 segments of ethylene oxide (NP10 or NP30). Supports were glass plates or poly(ethylene terephthalate) films. Adhesion was measured by a peel test at 180°. Loci of failure were determined by multitechnique analysis of the surfaces revealed after peeling. At medium and high peel rates, the peel energy versus surfactant concentration curves show either a maximum or a minimum, depending on the surfactant. When the peel rate is decreased, these maxima and minima flatten out and, at zero peel rate (extrapolated values), the peel energy becomes independent of the surfactant concentration. Surfaces analyses revealed that the surfactant is always present at the locus of failure. Rupture takes place in a thick (above 10 nm) (SDS), in a thin (a few nanometers) (NP30), or at the top of a surfactant layer (HPCI). The locus of failure is independent of the peel rate and of the surfactant concentration. The conclusion is that the surfactant strongly influences adhesion properties of latex films but several points remain unexplained.

Introduction L’anesthesie intraveineuse est une strategie anesthesique connue pour reduire l’incidence des nausees et vomissements postoperatoires (NVPO). L’objectif de cette etude est de determiner l’incidence des NVPO et d’evaluer l’impact d’une bitherapie preventive dans le cadre de la chirurgie de l’obesite lors de l’utilisation d’un systeme d’asservissement de l’anesthesie intraveineuse a partir de l’index bispectral. Materiel et methodes Apres accord du comite de protection des personnes, nous avons mene une etude controlee randomisee monocentrique en double insu, comparant l’association peroperatoire dexamethasone (4 mg)/ondansetron (4 mg) (DO) versus placebo (CTL) pour la prevention des NVPO. Les patients majeurs a haut risque de NVPO (Apfel ≥ 2) durant une chirurgie laparoscopique de gastroplastie verticale calibree avec resection gastrique ont ete inclus apres recueil ecrit de leur consentement. L’anesthesie totale intraveineuse a consiste en l’administration automatisee de propofol et de remifentanil guidee par le BIS [1] . Le critere de jugement principal a ete l’incidence des nausees severes (≥ 4/10 par echelle verbale simple) et des vomissements durant les 24 premieres heures postoperatoires. L’analyse a egalement porte sur la necessite d’administrer un traitement de secours durant cette periode. Resultats Sur 123 patients inclus, 117 ont ete analysables. Les caracteristiques des patients et de l’anesthesie sont resumees dans le tableau ci-dessous ( Tableau 1 ). Dix-neuf pour cent des patients dans le groupe DO et 20 % dans le groupe CTL ont presente le critere de jugement principal ( p = 1). Quarante-trois pour cent des patients dans le groupe DO et 54 % des patients dans le groupe CTL ont necessite l’administration d’un traitement antiemetique de secours ( p = 0,31). Discussion La prevention n’a pas reduit l’incidence des NVPO dans ce contexte anesthesique. Dans cette etude sans groupe utilisant des halogenes, cette incidence est faible. L’etude de l’effet d’une augmentation des doses des traitements de prevention des NVPO est a envisager dans cette population de patients obeses.

A review of the new problems encountered in space control, essentially due to structural interaction with flexible modes and complex dynamics of multi-payload satellites, has confirmed that classical control methods turn out to have shortcomings. Modem techniques of control, from Linear Quadratic to Hoo methods, have been studied in order to determine whether they are well suited to this class of problems. The most promising ones were tested on simplified models to verify coarsely their feasibility and performances. In parallel, a purpose-built software tool combining Computer Aided Design for automatics and symbolic manipulation of dynamic equations is being developed to help control designers faced with these new problems.