Influence of spatial coherence on scattering by a particle

We analyze the effect of partial spatial coherence on the scattering of light by an arbitrary particle. We extend the definition of the extinction cross section to spatially partially coherent fields. We then discuss the effect of the partial coherence on the extinction scattering cross section by introducing the Wigner transform. It is shown that for rotationally invariant scatterers, the extinction cross section does not depend on the coherence of the incident field. The effect of partial coherence on the angular behavior of the scattered intensity is also discussed in the framework of the Wigner transform. The implications for practical applications are considered.     

Definition of the diffusion coefficient in scattering and absorbing media

We revisit the definition of the diffusion coefficient for light transport in scattering and absorbing media. From an asymptotic analysis of the transport equation, we present a novel derivation of the diffusion coefficient, which is restricted neither to low absorption nor to a situation in which the specific intensity is quasi-isotropic. Our result agrees with previous expressions of the diffusion coefficient in the appropriate limit. Using numerical simulations, we discuss the implications of the proper choice of the diffusion coefficient for time-dependent transport.     

Fault detection and isolation in manufacturing systems with an identified discrete event model

In this article a generic method for fault detection and isolation (FDI) in manufacturing systems considered as discrete event systems (DES) is presented. The method uses an identified model of the closed-loop of plant and controller built on the basis of observed fault-free system behaviour. An identification algorithm known from literature is used to determine the fault detection model in form of a non-deterministic automaton. New results of how to parameterise this algorithm are reported. To assess the fault detection capability of an identified automaton, probabilistic measures are proposed. For fault isolation, the concept of residuals adapted for DES is used by defining appropriate set operations representing generic fault symptoms. The method is applied to a case study system.     

Corium spreading and coolability: CSC Project

In the context of severe accidents, large R&D efforts throughout the world are currently directed towards ex-vessel corium behaviour. Among the mitigation means which can be envisaged, the European industries and utilities are considering the implementation of a core-catcher outside the reactor pressure vessel in order to prevent basemat erosion and to stabilize and control the corium within the containment. The CSC project focused on two key phenomena for external core-catcher efficiency, reliability and safety: spreading and coolability. An experimental programme, covering different scenarios and including both simulant and real materials provided a lot of results which now constitute a large database and which enabled the qualification of computer codes.     

Sensitivity of slanted fibre Bragg gratings to external refractiveindex higher than that of silica

The influence of external refractive index higher than that of silica on the transmission spectra properties of slanted fibre Bragg grating in investigated. An analytical method is presented for their potential use as refractometer for refractive index ranges beyond 1.45     

Development of an improved falling ball viscometer for high-pressure measurements with supercritical CO2

This study presents the development of an improved technique for viscosity measurements under high pressure. The apparatus is based on the principle of the falling ball viscometer, implemented in a high-pressure autoclave fitted with visualisation windows. The originality here is that the balls fall through a tube open at both ends with a diameter slightly greater than that of the balls, allowing a simplified modelling and numerical simulation. A numerical approach has been used for viscosity determination. Calculations have been made with COMSOL Multiphysics^® with the laminar Navier-Stokes model for Newtonian mixtures. It includes the specific hydrodynamic effects without the need for a calibration fluid. However, validation experiments were carried out at atmospheric pressure with dimethylsulfoxide (DMSO) at 298, 308 and 318 K and with cocoa butter at 313 and 353 K, with values of viscosity in the range from 1.4 to 45.4 mPa s. Comparative measurements with literature data have been conducted with cocoa butter saturated with carbon dioxide at 313 and 353 K and for pressures ranging from 0.1 to 25 MPa. At 313 K, viscosity varies from 45.4 mPa s to 3.1 mPa s while at 353 K it varies from 12.4 to 1.9 mPa s. For both isotherms tested, within the range 0-15 MPa, the higher the CO₂ dissolution in the cocoa butter, the lower the viscosity. However, this decrease in viscosity is more pronounced at the lowest temperature. Above 15 MPa the CO₂ dissolution effect on viscosity becomes insignificant, i.e. within the experimental error, due to a counter effect linked with the high hydrostatic pressure. Furthermore, the limits of use of this method have been determined. This technique is revealed as reliable and can therefore be used with other binary systems.     

Room-temperature, selective detection of benzene at trace levels using plasma-treated metal-decorated multiwalled carbon nanotubes

Hybrid materials consisting of oxygen plasma-treated multiwalled carbon nanotubes decorated with metal nanoparticles (e.g., Rh, Pd, Au or Ni) can be tailored for the recognition of benzene vapors with high sensitivity and selectivity. Metal nanoparticles donate or accept a significant amount of charge upon adsorption of a target molecule, so as to affect electron transport in the nanotube. The plasma treatment enables the cleaning, activation, functionalization and metal decoration of carbon nanotubes in a single step, which offers enormous flexibility for tuning the interfacial properties of the resulting hybrid materials. When combined in a microsensor array operating at room temperature, the use of benzene-sensitive and benzene-insensitive metal-decorated multiwalled carbon nanotubes can provide selective detection of benzene at trace levels with a detection limit below 50 ppb.     

Differences in the aerosolization behavior of microorganisms as revealed through their transport by biogas

The aerosol microbial diversity of biogas was analyzed in order to examine the aerosolization behavior of microorganisms. Six biogas samples were analyzed: five from mesophilic and thermophilic anaerobic digestors treating different wastes, and one from landfill. Epifluorescent microscopic counts reveal that with 10(6) Prokarya m(-3), only one per one thousand billion were aerosolized from the digestor sludges to the biogas. SSU (Small Sub Unit) ribosomal fingerprinting (Single Strand Conformation Polymorphism) shows that microbial communities in the biogas were not just a rough copy of anaerobic digestor microbial communities and underlines that all microorganisms are not equally convoyed by biogas. To assess the difference occurring in aerosolization, 675 biogas-borne SSU ribosomal DNA were analyzed and compared to published anaerobic digestor microbial diversity. Results show that microorganisms belonging to Archaea, Deltaproteobacteria, Spirochaetes, Thermotogae, Chloroflexi phyla and sulfate-reducing groups were non-aerosolized whereas microorganisms belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, TM7 phyla as well as strictly aerobic and occasionally pathogenic species presented high levels of aerosolization. Finally, microorganisms belonging to Actinobacteria, Firmicutes and Bacteroidetes phyla represent passively-aerosolized microorganisms with similar frequencies in biogas-borne and anaerobic digestor microbial communities.     

Attentional load associated with performing and stabilizing preferred bimanual patterns.

This study aimed to determine whether the stability of preferred coordination patterns could be modified intentionally and whether such stabilization involved an additional attentional load. Eight participants performed in-phase and anti-phase bimanual coordination patterns, a reaction time (RT) task, and several dual tasks (coordination + RT) that manipulated attentional priority by requiring either shared attention, priority to the coordination task, or priority to the RT task. Results showed that RT was smaller for in-phase than anti-phase. Moreover, attentional manipulations led to a trade-off between pattern stability and RT performance. This suggests that performing and intentionally stabilizing a coordination pattern incur a central cost that depends on the coordination pattern's dynamic properties. Thus, this study opens a conceptual and methodological bridge between information processing and dynamic approaches to coordination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)