Potential influence of microorganisms on the corrosion of carbon steel in the French high- and intermediate-level long-lived radioactive waste disposal context

In the context of the high-level radioactive waste disposal CIGEO, the corrosion rate due to microbially influenced corrosion (MIC) has to be evaluated. In France, it is envisaged to dispose of high- and intermediate-level long-lived radioactive waste at a depth of 500 m in a deep geological disposal, drilled in the Callovo-Oxfordian claystone (Cox) formation. To do so, a carbon steel casing will be inserted inside disposal cells, which are horizontal tunnels drilled in the Cox. A specific cement grout will be injected between the carbon steel casing and the claystone. A study was conducted to evaluate the possibility of MIC on carbon steel in the foreseeable high radioactive waste disposal. The corrosiveness of various environments was investigated at 50°C and 80°C with or without microorganisms enriched from samples of Andra's underground research laboratory. The monitoring of corrosion during the experiments was ensured using gravimetric method and real-time corrosion monitoring using sensors based on the measurements of the electrical resistance. The corrosion data were completed with microbiological analyses including cultural and molecular characterizations.     

The impact of roasting on the ochratoxin A content of coffee

Roasting coffee led to a drop in the ochratoxin A (OTA) concentration, as measured by the reference method, especially for dark type roasts. The way the beverage was prepared also affected the OTA content, which could paradoxically be higher than that of the initial roasted coffee. Assays on the thermal stability of pure OTA showed that it ought to be found in larger quantities in roasted coffee. This suggested that OTA was masked by reactions with the substrate during roasting. The absence of OTA in green coffee is therefore the best guarantee of safety.     

Preparation of monodisperse polystyrene particles using thiol-ended polyethylene oxide stabilizer in dispersion polymerization

Summary Radical dispersion polymerization of styrene in aqueous ethanol solutions was performed in the presence of a new reactive polyethylene oxide stabilizer with thiol end groups. This reactive stabilizer was compared to the more conventional poly (N-vinylpyrrolidone). Particles size distribution, molecular weights and kinetics were investigated. We demonstrate that the thiol ended dispersant displays a high stabilizing efficiency. Particles size, molecular weights and conversions are strongly influenced by the amount of stabilizer used.     

Spectroscopic investigation of Nd ion in LiNbO3, MgO:LiNbO3 and LiTaO3 single crystals relevant for laser applications

The polarized absorption and luminescence properties of Nd³⁺ doped isostructural LiNbO₃, MgO:LiNbO₃ and LiTaO₃ nonlinear bulk single crystals are reported. Pump-probe experiments associated with the Judd-Ofelt approach are used to estimate two types of room temperature cross sections: polarized emission cross sections of the dominant ⁴F_3/2 → ⁴I_1//2 transition near 1085 and 1093 nm and polarized excited-state absorption cross sections in the same spectral domain and in the green spectral range corresponding to self frequency doubling. Self frequency-doubling results are also given in Nd:LiNbO₃ and Nd:MgO:LiNbO₃ versus sample temperature.     

A new low-power GaAs two-single-port memory cell

This paper describes an experimental static memory cell in GaAs MESFET technology. The memory cell has been implemented using a mix of several techniques already published in order to overcome some of their principal drawbacks related to ground shifting, destructive readout, and leakage current effects. The cell size is 36×37 μm² using a 0.6-μm technology. An experimental 32 word × 32 bit array has been designed. From simulation results, an address access time of 1 ns has been obtained. A small 8 word×4 bit protoype was fabricated. The cell can be operated at the single supply voltage from 1 up to 2 V. The evaluation is provided according to the functionality and power dissipation. Measured results show a total current consumption of 14 μA/cell when operated at 1 V     

Generalized Eigenvalue Decomposition Applied to Estimation of Spatial rPPG Distribution of Skin

Journal of Mathematical Imaging and Vision - Remote photoplethysmography (rPPG) has been at the forefront recently, thanks to its capacity in estimating non-contact physiological parameters such as...     

High solids content emulsions. III. Synthesis of concentrated latices by classic emulsion polymerization

Two different methods of producing bi‐ and trimodal latices of a mixture of methyl methacrylate, butyl acrylate, and small amounts of acrylic acid were tested. It is shown that a combination of concentrating blends of seed particles by semibatch reaction, followed by a nucleation of small particles plus a second semibatch phase allowed us to obtain stable latices with solids contents over 65% and viscosities of below 2500 mPa s^?1 with little coagulum formation. The key parameter in determining latex stability, coagulum formation, and viscosity appears to be the the particle size distribution, and especially its modification attributed to secondary nucleation. Because it is not possible to eliminate water‐soluble monomers from the polymerization recipe, secondary (homogeneous) nucleation must be minimized by careful addition of the free‐radical initiator and choice of monomer feed flow rates. The nucleation of the third population in the trimodal latices is best accomplished with a mixed surfactant system because renucleation by anionic surfactant alone leads to detrimental changes in the particle size distribution (PSD) resulting from excessive flocculation of particles. In addition, it was found that the viscosity of the final products was not sensitive to small changes in the ionic strength of the latex, although neutralization to a pH of 6 effectively doubles the final latex viscosity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1916–1934, 2002; DOI 10.1002/app.10513     

Reactive surfactants in heterophase polymerization. XVII. Influence of the surfactant on the mechanical properties and hydration of the films

In the context of a European union‐supported network on “Reactive Surfactants for Heterophase Polymerization,” different polymerizable surfactants (surfmers) have been synthesized and engaged in the emulsion polymerization of styrene, butyl acrylate, and acrylic acid. The thermomechanical properties of films cast from these different latices are reported in this article. The evolution of the mechanical properties with temperature and the effect of water molecules on these properties are studied. We observed that the studied surfactants do not influence the properties of the dry films. However, some differences due to grafting of reactive surfactants appeared when the films were wet. The amount of water uptake is drastically decreased when only reactive surfactants are present in the film. Concerning the mechanical behavior of the wet films, a decrease of the plastic flow stress is observed for all the samples whatever the nature of the surfactant (reactive or conventional). Hence, calorimetric measurements and dynamic mechanical analysis are used to identify the possible mechanisms that induce the change in the mechanical behavior of the latex films. In the case of reactive surfactant grafted to the polymer, the very low value of water uptake is accompanied by a plasticization of the polymer. In contrast, no plasticizing effect is observed in the case of nonreactive surfactant, even if the amount of water is very large. Finally, the tensile behavior of the styrene–butyl acrylate copolymer versus temperature is analyzed in the frame of the quasi point defects (qpd) model. Both rubber elasticity and chain orientation effects are taken into account to describe the behavior laws at large extensions (i.e., ? ≈ 1.2). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1686–1700, 2002; DOI 10.1002/app.10548     

New perfectly difunctional organolithium initiators for block copolymer synthesis: 2. Difunctional polymers of dienes and of their triblocks copolymers with styrene

New organodilithium initiators were prepared in a hydrocarbon solvent in the absence of any polar additive. Although these initiators are insoluble when they are synthesized, they may be easily purified and reacted with dienes to give perfectly telechelic polydienes having unimodal distributions and low dispersity. A good agreement between experimental and theoretical molecular weights was observed. The polymer microstructures were similar to those of polymers initiated by butyllithium in the same solvent. Triblock thermoplastic elastomers were also prepared, the characteristics of which are given. The mechanical properties of a S.B.S. sample support also the claim of a good initiating ability and difunctionality of these initiators.