Membrane performance in combined processes including ozonation or advanced oxidation, powdered activated carbon and coagulation — Investigations in pilot scale

In Luxembourg the largest drinking water production plant treating reservoir water with conventional technology including ozonation is in operation since 1969. Its maximum capacity is 64,000 m³/d. After 40 years of operation the need for both modernizing and extension of capacity to 100,000 m³/d emerged. Nowadays, due to new developments in technology and research it is possible to assess the water treatment processes more effectively with regard to current and future requirements. Against this background, membrane processes combined with conventional and advanced processes were identified as potential option and long term pilot-scale tests were started in June 2008. Different treatment process schemes all including membranes are investigated in a one year pilot plant period. Various treatment steps such as different pre- and post-treatment steps, various membranes and membrane materials and also conventional treatment steps are compared and assessed.     

Virtual reality for cultural landscape visualization

Although land managers and policy-makers generally have a good experience of what result can be expected from their decisions, they are often faced with difficulty when trying to communicate the visual impact of a management option to stakeholders, particularly when the landscape exhibits a high cultural value. Three-dimensional visualization of the landscape is often used for communicating with the stakeholders. A challenge in participatory methods for integrated assessment and policy planning is to view future changes in land use, according to scenarios. A 3-D landscape visualization component, SLE (“Seamless Landscape Explorer”), has been developed, which is launched after a scenario simulation to allow for exploration of landscape changes. Pressures causing such changes are translated into changes in the spatial configuration of the landscape. The different types of land-use are visualized thanks to a library of detailed textures, and vegetation can be added. This has been applied to a study of four scenarios in the French Mediterranean region, which were set up as part of a participatory process for discussing the planning of the regional peri-urban and agricultural policy, in an area dominated by the typical culturally sensitive Mediterranean matorral, (“garrigue” shrubland) surrounding the Pic Saint-Loup mountain. Examples of visualization are shown and discussed here.     

Aquifex aeolicus membrane hydrogenase for hydrogen biooxidation: Role of lipids and physiological partners in enzyme stability and activity

Hydrogenase I from the hyperthermophilic bacterium Aquifex aeolicus is a good candidate for biotechnological devices thanks to its ability to oxidize hydrogen at high temperature, even in the presence of oxygen and CO. In order to enhance the enzyme stability and the catalytic efficiency, we investigated the hydrogen oxidation process with hydrogenase I embedded in a physiological-like environment. Hydrogenase I partners in the metabolic chain, namely membrane quinone and cytochrome b, were purified and fully characterized. The complex hydrogenase I–cytochrome b was inserted into liposomes. Surface Plasmon Resonance revealed that quinone took part in the stabilization of the complex. By use of molecular modelization and electrochemistry analysis, enzyme stability has been demonstrated to be stronger and enzymatic efficiency to be five times higher when hydrogenase is embedded into the liposomes. This result raises the possibility of using hydrogenases as biocatalysts in fuel cells.     

3-D deformable image registration: a topology preservation scheme based on hierarchical deformation models and interval analysis optimization.

This paper deals with topology preservation in three-dimensional (3-D) deformable image registration. This work is a nontrivial extension of, which addresses the case of two-dimensional (2-D) topology preserving mappings. In both cases, the deformation map is modeled as a hierarchical displacement field, decomposed on a multiresolution B-spline basis. Topology preservation is enforced by controlling the Jacobian of the transformation. Finding the optimal displacement parameters amounts to solving a constrained optimization problem: The residual energy between the target image and the deformed source image is minimized under constraints on the Jacobian. Unlike the 2-D case, in which simple linear constraints are derived, the 3-D B-spline-based deformable mapping yields a difficult (until now, unsolved) optimization problem. In this paper, we tackle the problem by resorting to interval analysis optimization techniques. Care is taken to keep the computational burden as low as possible. Results on multipatient 3-D MRI registration illustrate the ability of the method to preserve topology on the continuous image domain.     

Trailer truck trajectory optimization: the transportation of components for the Airbus A380

European aircraft manufacturer, Airbus, has started a program to develop the largest aircraft ever built, the Airbus A380, which would be able to carry between 550 to 800 passengers on two decks. The six components of the airplane are to be produced in different European cities. They need to be transported from these cities to Toulouse, France, for assembly, and several means of transportation have been investigated. The sizes of the freights, the length of the itinerary, and the narrowness of the critical passages constitute a challenge that classical transportation techniques in the domain of oversized convoys cannot easily overcome. Therefore, Airbus and the French national agency in charge of road management launched a research and development project divided into two parts. The objective of the first part is to adapt functions first to develop for mobile robots to the complex kinematics of trailer-truck systems and integrating these functions into a software platform. The second part of the project aims to define and develop a computer-aided driving system on board the vehicles in order to help the drivers carry out their task. This paper provides a brief overview of the state of the art in trajectory planning for mobile robots and vehicles, and discusses the development of original solutions to address both the kinematic complexity of one of the vehicles and the need to optimize the distance to obstacles.     

Proton microbeam induced damages in glasses: Ca and Na distribution modification

Nowadays, nuclear microprobes are commonly used in Earth Sciences as an analytical tool to detect a large number of trace elements in geological samples. However, radiation damages induced in natural glasses during an analysis by ionization are not completely controlled. Some difficulties remain in defining the appropriate analytical conditions without modifying the alkaline distribution in the matrix. Our approach consists of using a synthetic glass to quantify these modifications. With a 2 MeV proton microbeam, the Na and Ca signal evolution has been followed as a function of the deposited charge. Na and Ca distribution maps in and around the beam impact evidence a complex remobilization of both elements. The use of three different proton energies (1.32 MeV, 2MeV and 3MeV) permits the Na and Ca distribution profiles to be realized for increasing depth layers. A similar behavior of alkaline elements has been found within complex natural glasses.     

Magnetically responsive polypyrrole nanotubes using Ce(III)-stabilized maghemite nanoparticles

Nanocomposites (NCs) that are made magnetically responsive in controlled conditions attract continuing interest for their added magnetic properties. In this study, we report on the preparation and full characterization of a multifunctional NC composed of magnetic γ-Fe(2)O(3) nanoparticles (NPs) covalently attached to the surface of polyaminated (polyNH(2)) poly(2,6-di-pyrrol-1-yl-hexanoic acid) (pDPL) nanotubes (NTs). Such a hybrid conducting polymer iron oxide maghemite γ-Fe(2)O(3)@pDPL NC built specifically on covalent bonding has never been reported. The maghemite γ-Fe(2)O(3) NPs were prepared using an innovative ultrasound-assisted Ce(3+) doping process, resulting in polycarboxylation of the NP surface useful for control of aggregation and derivatization of functionality. The second component of the NC, i.e. polyNH(2)-modified pDPL NTs, was prepared from an acid functional pyrrole species followed by amine modification. The resulting innovative γ-Fe(2)O(3)@pDPL NC can be viewed as a multifunctional nanomaterial since it possesses both types of derivatization, i.e. polyCOOH (NPs) and polyNH(2) (NTs) combined with magnetic responsivity.     

Convection naturelle dans une boîte rectangulaire légèrement inclinée contenant un milieu poreuxNatural convection in a slightly slanted rectangular box filled with a porous medium

Steady natural convection in a rectangular slightly inclined box filled with a porous medium is studied. If the lower plate is heated and the aspect ratio large, the structure of the flow is simple as long as the Rayleigh number remains sub-critical. If the upper plate is heated, a boundary layer regime appears provided that the Rayleigh number is high. The Nusselt number is calculated by the Galerkin method and shown to approximate in this particular case to the following expression: Nu= 1 + 0,16k^3/2Ra*^1/42     

Reducing the diffraction artifacts while implementing a phase function on a spatial light modulator

Spatial light modulators are often used to implement phase modulation. Since they are pixelated, the phase function is usually approximated by a regularly sampled piecewise constant function, and the periodicity of the pixel sampling generates annoying diffraction peaks. We theoretically investigate two pixelation techniques: the isophase method and a new nonperiodic method derived from the Voronoi tessellation technique. We show that, for a suitable choice of parameters, the diffraction peaks disappear and are replaced by a smoothly varying halo. We illustrate the potential of these two techniques for implementing a lens function and wavefront correction.