A model for real-time on-surface flows

Simulating fluid flows for visualization purposes is known to be one of the most challenging fields of the computer graphics domain. While rendering vast liquid areas has been widely addressed this last decade, few papers have tackled the problematic of on-surface flows, even though real-time applications such as drive simulators or video games could greatly benefit from such methods. We present a novel empirical method for the animation of liquid droplets lying on a flat surface, the core of our technique being a simulation operating on a 2D grid which is implementable on GPU. The wetted surface can freely be oriented in space and is not limited to translucent materials, the liquid flow being governed by external forces, the viscosity parameter and the presence of obstacles. Furthermore, we show how to simply incorporate in our simulation scheme two enriching visual effects, namely absorption and ink transport. Rendering can be achieved from an arbitrary view point using a GPU image based raycasting approach and takes into account the refraction and reflection of light. Even though our method doesn’t benefit from the literature of fluid mechanics, we show that convincing animations in terms of realism can be achieved in real-time.     

Hydrotreating catalysts, an old story with new challenges

Environmental constraints and energy saving concerns are strong driving forces for improving the quality of fuels. In particular, deep hydrodesulphurization and dearomatization of diesels are mandatory. Preparation or modification of optimized hydrotreating catalysts are related to scientific bases and precise knowledge of the real active sites during operating conditions. This paper will review the updated results on the most promising model attempting to explain the catalytic synergy in hydrodesulphurization and the recent evolution of the formulation of such catalysts.     

Production of listeriolysin O by Listeria monocytogenes (Scott A) under heat-shock conditions.

Early stationary phase cells of Listeria monocytogenes (Scott A) were examined to determine the effect of heat-shock on the production of listeriolysin O (LLO) during and after resuscitation at 37 degrees C. Cells were subjected to a heat-shock at 48 degrees C for 1 h. Intracellular and extracellular proteins of the heat-shocked cells were assayed for LLO using a microtiter plate hemolysis assay and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Our results showed that significant amounts of LLO are synthesized under heat-shock conditions that are not detected in the extracellular medium by a functional assay. This situation is evident by the absence of hemolytic activity immediately after heat-shock, and may be due to either a lack of excretion or inactivation of the LLO at 48 degrees C once outside the cell. By studying the intracellular and extracellular proteins using SDS-PAGE and immunoblots of the heat-shocked cells, we substantiated an absence of excretion as an operating mechanism. Heat-shocked cells resumed LLO production within 2-4 h of resuscitation at 37 degrees C, achieving an activity level 2-fold higher compared to the controls and 4-fold higher compared to cells immediately after heat-shock. Most likely, the LLO excreted must have been from LLO accumulated in the cells during heat-shock.     

Selective methane detection under varying moisture conditions using static and dynamic sensor signals

This paper reports the development of a methane analyser, which meets some of the requirements of a reliable domestic methane detector. The equipment is based on a five-element array that includes four tin oxide gas sensors and a humidity sensor. The pattern recognition engine is based on multilayer perceptron (MLP) neural networks trained with the back-propagation algorithm. Both static and dynamic signals from the sensors are fed into the neural networks to identify and quantify methane and ethanol. The system identifies and quantifies unknown samples of these contaminants, even when the ambient relative humidity varies broadly (from 25% to 80%). As a result, the equipment detects methane, rejects false alarms caused by ethanol and complies with some aspects of the European directive for domestic methane detectors.     

Modeling the effect of coating weight on the kinetics of iron enrichment in hot dip galvanneal coatings on interstitial-free steel sheets

The coating weight is shown to have a significant effect on the isothermal kinetics of iron enrichment in hot dip galvanized coatings on interstitial-free (IF) steel sheets during a postcoating heat treatment that simulates galvannealing. A simple quantitative model is proposed to account for this effect and is found to give reasonable agreement with the experimental results obtained for the kinetics of iron enrichment for coating weights of 60 and 80 g/m².     

Preparation of nano‐sized silica/poly(methyl methacrylate) composite latexes by heterocoagulation: comparison of three synthetic routes

Continuing earlier work, 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as a cationic initiator to generate positively charged polymers, and promote interaction of these polymers with the negatively charged surface of colloidal silica particles in aqueous solution. Three different synthetic routes have been investigated. In a first route, emulsion polymerization of MMA, initiated by AIBA, was performed directly in an aqueous suspension of the silica beads using a non‐ionic polyoxyethylenic surfactant (NP₃₀). In a second route, AIBA was first adsorbed on the silica surface, and the free amount of initiator was discarded from the suspension. The silica‐adsorbed AIBA adduct was suspended in water with the help of surfactant, and used to initiate the emulsion polymerization of MMA. In a third route, cationic PMMA particles were synthesized separately and subsequently adsorbed on the silica surface. Whatever the approach used for their elaboration, the colloidal nanocomposites were shown to exhibit a raspberry‐like morphology. Quantitative determination of the amount of surface polymer enabled us to evaluate the efficiency of the heterocoagulation process and establish a comparison among the three synthetic routes. Copyright © 2004 Society of Chemical Industry