This work demonstrates that in advection-diffusion Lattice Boltzmann schemes, the local mass-conserving boundary rules, such as bounce-back and local specular reflection, may modify the transport coefficients predicted by the Chapman-Enskog expansion when they enforce to zero not only the normal, but also the tangential boundary flux. In order to accommodate it to the bulk solution, the system develops a Knudsen-layer correction to the non-equilibrium part of the population solution. Two principal secondary effects-(i) decrease in the diffusion coefficient, and (ii) retardation of the average advection velocity, obtained in a closed analytical form, are proportional, respectively, to freely assigned diagonal weights for equilibrium mass and velocity terms. In addition, due to their transverse velocity gradients, the boundary layers affect the longitudinal diffusion coefficient similarly to Taylor dispersion, as they grow as the square of the Péclet number. These numerical artifacts can be eliminated or reduced by a proper space distribution of the free-tunable collision eigenvalue in two-relaxation-time schemes.

No abstract

Despite the fact that Information and Communication Technologies (ICTs) are considered to be an important state modernization tool, resistance to change can sometimes be observed. The question is why? On the basis of intervention research mobilizing five different corpuses of material over eight years in the family branch of the French social security system, we have established that values can be an (accelerating or blocking) structuring element of an ambiguous e-administration development dynamic. In other words, in the process of enacting or activating technologies intended to modernize public services, sensemaking by managers faced with the conflicts of values generated or exacerbated by the introduction of these new management tools is fundamental to understanding the process of change. Based on this research result, recommendations for action have been drawn up for the managers, the aim being to elucidate these value conflicts within discussion forums, even if this implies a certain cost. Points for practitioners This article shows that the e-administration development dynamics depend in part on sensemaking by public service managers around technologies. Indeed, these technologies exacerbate or introduce conflicts of values. Interactivity (a property inherent to ICT that must be respected for the sake of the value of public service adaptability), in particular, may conflict with the value of public sector equality. This is at least what we have observed in the course of the research conducted for nearly eight years in the family branch of the French social security system. This therefore raises questions about the effectiveness of elucidating these value conflicts within discussion forums to facilitate the development of e-administration.

Material effective properties of composite media or their acoustic performance are often required to be experimentally determined or verified. For underwater applications, systems can be characterized in an open water tank in which a conventional measurement configuration consists of the panel, an acoustic source, and two hydrophones, one on either side of the panel. However, panel measurements may be greatly complicated by waves diffracted by the panel edges. The three-point method is a technique that decomposes total pressure into contributions of the incident, reflected, transmitted, and edge-diffracted pressures. These contributions are determined using measurements at three positions. Reflection and transmission coefficients can then be obtained by removing the contribution of the edge-diffracted waves. The three-point method is applied to an aluminum reference panel for which the experimental scattering coefficients are in very good agreement with those of an infinite panel. The validity limits of the method are also studied. Finally, a pressure mapping shows that the three-point method leads to an accurate determination of the reflection and transmission coefficients for different positions despite strong variations of the edge-diffracted pressure. V

Résumé Les apports de l’administration électronique à l’amélioration de la qualité de service sont nombreux. Pour autant, l’usage des technologies de l’information et de la communication (Tic) dans la modernisation de l’État permet-il réellement de « reconcevoir » les services pour satisfaire les besoins explicites, implicites ou latents (autrement dit les attentes) des usagers ? L’article montre que, si le taux de satisfaction envers les sites publics est particulièrement élevé en France, des questionnements demeurent sur la maîtrise des données personnelles, la sécurité des échanges et la fracture numérique.