Savoir-faire de la pierre sèche et terrasses de cultures cévenoles

La présence d’un membre du Centre de la Méditerranée Moderne et Contemporaine à ce colloque très dense (nombreux intervenants et environ 120 personnes dans l’auditoire) visait un triple objectif : approfondir les connaissances sur les terrasses soutenues par des murs en pierres sèches, constater le type et le niveau des interventions sur ce sujet et prendre des contacts avec des acteurs politiques pour mettre en place une équipe de travail dans les Alpes-Maritimes. L’introduction au colloque ..

Photochemical UV/TiO2 treatment of olive mill wastewater (OMW)

Olive mill wastewater (OMW) was treated by photocatalysis using TiO2 under UV irradiation on the laboratory scale. The chemical oxygen demand, the coloration at 330 nm, and the level of phenols all showed decreases which, after a 24-h treatment, reached 22%, 57% and 94%, respectively. The differences between these three values indicate the persistence of colourless, non-phenolic compounds. Application of the novel Fictitious Atomic-Group Separation method showed an increase in carbon oxidation state and confirmed that the attack primarily concerns, aromatic moieties. A fine spectroscopic study revealed the occurrence of three successive phases during the degradation process, thought to correspond to three different categories of molecules in the OMW and the presence of pectin compounds

Structural characterization of humic acids, extracted from sewage sludge during composting, by thermochemolysis–gas chromatography–mass spectrometry

Thermochemolysis coupled with gas chromatography and mass spectrometry were applied to determine the structure of humic acids (HA) extracted from a sewage sludge and straw mixture at different steps of composting. The HA extracted from sludge mixture released various compounds, such as mono-, di-, tri-methoxy (alkyl) benzene and (alkyl) benzoic acids, which originated from lignin like derivatives of phydroxyphenyl, guiaicyl and syringyl units. In addition, other aromatic non-lignin derived structures were found along with series of branched C15, linear C16, C18 fatty acid methyl esters. The follow-up of various lignin-derived units during composting shows a decrease in phydroxyphenyl type-compounds (C) after the stabilisation phase. In parallel the more oxidized units, derived from guaiacyl (G) and syringyl (S) units, corresponding mainly to methylated derivatives of cafeic acids, protocatechuic acids, gallic acids and aldehydes, significantly increased in comparison with the other aromatic structures. Various ratios commonly used as parameters to determine the degree of lignin decomposition during humification were followed to monitor the chemical structure changes of the HA extracted from sludge mixture during composting. In the present case, the S/G ratio did not present significant changes during composting. The acid/aldehyde ratio was supervised using the ratio of gallic acids to gallic aldehyde methylated derivatives and showed an increase from 0.73 to 2.13 after the stabilisation phase but a decrease to 0.93 at the end of composting. This evolution may be explained by the increase of acid-containing derivatives following the intense oxidation of lignin side-chains during the stabilisation phase. But, the decrease of the acid/aldehyde ratio during the maturation phase could be attributed to a decrease in acid units by polymerisation of benzoic acid type-compounds through ester/ether linkages. The follow up of six families of compounds of similar chemical structures during composting showed a decrease of lignin-type compounds C6–C3 and that C6–C1 units predominated in the humic acid isolated from end compost sludge. The fatty acid methyl esters showed an increase in the intermediate phase of composting probably originating from the activities and tissues of microorganisms, which are numerous during the process. The final decrease in the amount of fatty acids may be explained by the death of most of the microbial population at the end of composting typified by a low respiratory rate. The index of Shannon-Weaver (Ish) remained constant at about 3 in course of composting indicating the neoformation of HA from subunits of similar chemical nature. A similitude index (Sij, S0 i j) showed a split between 30 and 90 days of composting indicating a change in the rate of neoformation of HA after a stabilisation phase. Afterwards, the rate of HA neoformation varied linearly with the duration of composting

Âge K/Ar et contrôle structural de mise en place des veines épithermales à Au-Ag de la Cordillera Shila, Sud Pérou.

International audienceThe Au-Ag epithermal mineralization of the Shila Cordillera is dated at about 10.7 Ma (K/Ar on adularia). The vein system is characterized by the association of a major east-west vein and N120-135°E secondary fractures. The strike-slip faults controlling the veins indicate an initial NE-SW to ENE-WSW shortening direction, which is compatible with that generally accepted for this period. These structures were reopened during a second phase and channelized mineralizing fluids, the circulation of which may have began at the end of stage 1.Les minéralisations épithermales à Au-Ag de la Cordillera Shila sont datées à environ 10,7 Ma (K/Ar sur adulaire). Le système de veines est caractérisé par l'association entre une veine principale sensiblement est-ouest et des fractures satellites N120 à N135°E. Les décrochements contrôlant les veines indiquent une direction de raccourcissement initiale NE-SW à ENE-WSW, compatible avec celle généralement admise pour cette période. Dans un deuxième stade, ces structures sont ré-ouvertes pour servir de réceptacle aux fluides minéralisateurs, dont la circulation débute probablement dès la fin du stade 1

Comparing Free Hand Menu Techniques for Distant Displays using Linear, Marking and Finger-Count Menus

Part 1: Long and Short PapersInternational audienceDistant displays such as interactive Public Displays (IPD) or Interactive Television (ITV) require new interaction techniques as traditional input devices may be limited or missing in these contexts. Free hand interaction, as sensed with computer vision techniques, presents a promising interaction technique. This paper presents the adaptation of three menu techniques for free hand interaction: Linear menu, Marking menu and Finger-Count menu. The first study based on a Wizard-of-OZ protocol focuses on Finger-Counting postures in front of interactive television and public displays. It reveals that participants do choose the most efficient gestures neither before nor after the experiment. Results are used to develop a Finger-Count recognizer. The second experiment shows that all techniques achieve satisfactory accuracy. It also shows that Finger-Count requires more mental demand than other techniques.</p

Caractérisation numérique et expérimentale en phase transitoire d'une sonde de température dans une enceinte close sous vide et à la pression atmosphérique

Ce travail présente les résultats numériques et expérimentaux concernant une sonde de température pour les mesures en écoulements gazeux instationnaires. La sonde de température, développée au laboratoire, est constituée d'un microthermocouple en couche mince intégré dans une gaine céramique introduite dans une vis. Les applications concernent les transferts de chaleur pariétaux rencontrés dans les écoulements oscillants de gaz chauds tels que ceux rencontrés dans les moteurs à combustion interne

Subcutaneous phaeohyphomycosis due to Phialemoniopsis ocularis successfully treated by voriconazole

International audienceWe report a case of subcutaneous infection in a 67 year-old Cambodian man who presented with a 5-month history of swelling of the right foot. Histopathology was compatible with phaeohyphomycosis and the hyphomycete Phialemoniopsis ocularis was identified by the means of morphological and molecular techniques. The patient responded well to a 6-month oral treatment with voriconazole alone

Effect of compressive strain rate on auxetic foam

Auxetic foams have previously been shown to have benefits including higher indentation resistance than their conventional counterparts, due to their negative Poisson’s ratio, making them better at resisting penetration by concentrated loads. The Poisson’s ratio and Young’s modulus of auxetic open cell foams have rarely been measured at the high compressive strain rates typical during impacts of energy absorbing material in sporting protective equipment. Auxetic closed cell foams are less common than their open cell counterparts, and only their quasi-static characteristics have been previously reported. It is, therefore, unclear how the Poisson’s ratio of auxetic foam, and associated benefits such as increased indentation resistance shown at low strain rates, would transfer to the high strain rates expected under impact. The aim of this study was to measure the effect of strain rate on the stiffness and Poisson’s ratio of auxetic and conventional foam. Auxetic open cell and closed cell polymer foams were fabricated, then compression tested to ~80% strain at applied rates up to 200 s−1, with Poisson’s ratios obtained from optical full-field strain mapping. Open cell foam quasi-static Poisson’s ratios ranged from −2.0 to 0.4, with a narrower range of −0.1 to 0.3 for closed cell foam. Poisson’s ratios of auxetic foams approximately halved in magnitude between the minimum and maximum strain rates. Open cell foam quasi-static Young’s moduli were between 0.02 and 0.09 MPa, whereas closed cell foams Young’s moduli were ~1 MPa, which is like foam in protective equipment. The Young’s moduli of the auxetic foams approximately doubled at the highest applied strain rate of 200 s−1

Une modélisation géométrique itérative basée sur les automates

Nous présentons un modèle itératif inspiré du modèle CIFS (Controlled Iterative Function System) de PRUSINKIEWICZ [PH94] - encore appelé RIFS (Recurrent Iterative Function System) par BARNSLEY ou MRIFS (Mutually Recursive Iterative Function System) par CULIK [CD93] -. Le principe de ces modèles est de définir des familles de figures géométriques avec des règles de production et des systèmes d’équations. Dans cet article, nous en présentons deux généralisations, qui permettent de contrôler la géométrie et la topologie des formes produites