High-Reynolds shallow flow over an inclined sinusoidal bottom

An experimental study of a turbulent free-surface shallow flow over an inclined sinusoidal bottom with a fixed corrugation amplitude is presented. A parametric analysis is performed by varying both the inclination angle and the Reynolds number. We show that a “Pulse-Waves” regime, dominant for Reynolds smaller than 4 000, coexists with a “Roll-Waves” regime, which becomes dominant above this value. The relative energy of the waves is quantified in the parameter space. At Reynolds numbers larger than 8 000, these wave instabilities disappear

Linear stability of the 1D Saint-Venant equations and drag parameterizations

The stability of the homogeneous and steady flow based on the one-dimensional Saint-Venant equations for free surface and shallow water flows of constant slope is derived and displayed through graphs. With a suitable choice of units, the small and large drag limits, respectively, correspond to the small and large spatio-temporal scales of a linear system only controlled by the Froude number and two other dimensionless numbers associated with the bottom drag parameterization. Between the small drag limit, with the two families of marginal and non-dispersive shallow water waves, and the large drag limit, with the marginal and non-dispersive waves of the kinematic wave approximation, dispersive roll waves are detailed. These waves are damped or amplified, depending on the value of the three control parameters. The spatial generalized dispersion relations are also derived indicating that the roll-wave instability is of the convective type for all drag parameterizations

SaDA: From Sampling to Data Analysis—An Extensible Open Source Infrastructure for Rapid, Robust and Automated Management and Analysis of Modern Ecological High-Throughput Microarray Data

One of the most crucial characteristics of day-to-day laboratory information management is the collection, storage and retrieval of information about research subjects and environmental or biomedical samples. An efficient link between sample data and experimental results is absolutely important for the successful outcome of a collaborative project. Currently available software solutions are largely limited to large scale, expensive commercial Laboratory Information Management Systems (LIMS). Acquiring such LIMS indeed can bring laboratory information management to a higher level, but most of the times this requires a sufficient investment of money, time and technical efforts. There is a clear need for a light weighted open source system which can easily be managed on local servers and handled by individual researchers. Here we present a software named SaDA for storing, retrieving and analyzing data originated from microorganism monitoring experiments. SaDA is fully integrated in the management of environmental samples, oligonucleotide sequences, microarray data and the subsequent downstream analysis procedures. It is simple and generic software, and can be extended and customized for various environmental and biomedical studies

Physical and Optical Properties of Poly(3-AlkylThiophene) with a View to the Fabrication of a Highly Nonlinear Waveguide

Publisher: Bentham (ISSN: 1874-088X)International audienceIn order to take advantage of the very high nonlinear susceptibility of conjugated polymer materials, Poly(3-AlkylThiophene)s, P3AT, were synthesized in the laboratory. The physical, thermomechanical and linear optical propertiesof synthesized P3AT have been investigated and the first experimental attempts at creating nonlinear optical waveguides and determining their characteristics are presented. After synthesizing P3AT, the relationships between polymer chain characteristics and mechanical properties are investigated to see if the polymer is suitable for optical waveguide process technology. We also examine the optical attenuation of the synthesized material, a crucial factor in anticipating the relative opacity of the future component. For the first time we present the absorption spectrum of 3-Octylthiophenemolecules in the Near Infra-Red (NIR) region that suggests optical losses for the material are about 0.6 dB.cm-1 at 1550 nm. Next we examined several waveguide structures such as ridge, buried and Strip Loaded WaveGuides (SLWG) based on P3AT material. For the buried waveguides, we have observed the signal transmission and in our opinion the low optical transmission of P3AT ridge and SLWG could be attributed to extrinsic losses (mainly scattering) due to both the remaining insoluble products in the polymer and to the poor adhesion between optical layers

Fiber Optic Research in France: Editorial for the Special Issue

International audienc

Special Issue: Fiber Optic Research in France (Part I of III)

International audienceThis review issue gives an accurate insight into the research work being carried out by the principal research and industrial establishments in our country, without claiming to offer a list of active researchers which is entirely complete. We believe the work herein will show a French research community which is active over a wide range of activities. The work presented covers fabrication of specialty fibres, fibre based components, test and characterisation and some more industrial aspects involving equipment providers. This Special Issue of Fiber an Integrated Optics, was appearing in three separate issues in 2008 and 2009

SaDA: From Sampling to Data Analysis—An Extensible Open Source Infrastructure for Rapid, Robust and Automated Management and Analysis of Modern Ecological High-Throughput Microarray Data

One of the most crucial characteristics of day-to-day laboratory information management is the collection, storage and retrieval of information about research subjects and environmental or biomedical samples. An efficient link between sample data and experimental results is absolutely important for the successful outcome of a collaborative project. Currently available software solutions are largely limited to large scale, expensive commercial Laboratory Information Management Systems (LIMS). Acquiring such LIMS indeed can bring laboratory information management to a higher level, but most of the times this requires a sufficient investment of money, time and technical efforts. There is a clear need for a light weighted open source system which can easily be managed on local servers and handled by individual researchers. Here we present a software named SaDA for storing, retrieving and analyzing data originated from microorganism monitoring experiments. SaDA is fully integrated in the management of environmental samples, oligonucleotide sequences, microarray data and the subsequent downstream analysis procedures. It is simple and generic software, and can be extended and customized for various environmental and biomedical studies

Investigation on optical waveguide realisations based on polymers with large third order non-linear susceptibility

conference 6999 « Organic Optoelectronics and Photonics », poster session [6999-67], http://spie.org/x24034.xmlInternational audienceConjugated polymer materials have great potential to be suitable candidates for use in all-optical network communications. They possess ultra-fast response times and a large third order non-linearity compared to minerals (third order susceptibility Χ(3) of conjugated polymers can be 4 orders of magnitude larger than that of fused silica). Such large non-linearities would allow the fabrication of compact all-optical devices at low power levels. Here we present the first investigations into the creation of a conjugated polymer single mode optical waveguide based on Poly(3- AlkylThiophene) (P3AT). We first synthesized the P3AT and tried to control the chemical reaction conditions in order to improve polymer solubility in common organic solvents. In parallel, we studied the engineering of P3AT single mode waveguide structures made by photolithography techniques which requires the adjustment of P3AT thermo-mechanical properties. Recently, we have been able to fabricate and measure the parameters of Strip-Loaded and buried waveguides with usual polymers. We intend to adapt these processes to obtain the first P3AT single mode optical waveguide

Intérêt des « Strip Loaded Waveguides » pour la réalisation de guides polymères à fort ki(3)

session Affiches [P68]National audienceLe présent article montre comment une technologie de guidage optique induit par un ruban, les "Strip Loaded WaveGuides", permet de réaliser des guides optiques polymères avec des matériaux difficiles à structurer par les techniques habituelles. Dans un premier temps, nous validons expérimentalement le concept à l'aide de polymères conventionnels et nous mettons en évidence les paramètres permettant d'induire dans une couche de matériau un guidage monomodal avec un confinement de lumière sufffisant. puis nous montrons comment tirer avantage de ce procédé pour réaliser des guides en poly(3-alkylthiophène) autrement que par une techniologie "ridge"

Potential of optical circuits integration with polymer technology

session ThA3 "Hybrid integrated optical circuits" [ThA3-2]International audienc