Submillimetre/TeraHertz Astronomy at Dome C with CEA filled bolometer array

Submillimetre/TeraHertz (e.g. 200, 350, 450 microns) astronomy is the prime technique to unveil the birth and early evolution of a broad range of astrophysical objects. A major obstacle to carry out submm observations from ground is the atmosphere. Preliminary site testing and atmospheric transmission models tend to demonstrate that Dome C could offer the best conditions on Earth for submm/THz astronomy. The CAMISTIC project aims to install a filled bolometer-array camera with 16x16 pixels on IRAIT at Dome C and explore the 200-$\mu$m windows for potential ground-based observations.Comment: 6 page

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Bioinspired bactericidal surfaces with polymer nanocone arrays

Infections resulting from bacterial biofilm formation on the surface of medical devices are challenging to treat and can cause significant patient morbidity. Recently, it has become apparent that regulation of surface nanotopography can render surfaces bactericidal. In this study, poly(ethylene terephthalate) nanocone arrays are generated through a polystyrene nanosphere-mask colloidal lithographic process. It is shown that modification of the mask diameter leads to a direct modification of centre-to-centre spacing between nanocones. By altering the oxygen plasma etching time it is possible to modify the height, tip width and base diameter of the individual nanocone features. The bactericidal activity of the nanocone arrays was investigated against Escherichia coli and Klebsiella pneumoniae. It is shown that surfaces with the most densely populated nanocone arrays (center-to-center spacing of 200 nm), higher aspect ratios (>3) and tip widths <20 nm kill the highest percentage of bacteria (∼30%)

UTILISATION D'ESTERASES ET DE LIPASES DANS L'OBTENTION DE COMPOSES PRESENTANT UN INTERET EN CHIMIE FINE

DANS CE TRAVAIL, DES ENZYMES HYDROLYTIQUES COMME DES ESTERASES ET DES LIPASES ONT ETE UTILISEES AUSSI BIEN POUR FAIRE DES REACTIONS D'HYDROLYSE ENANTIOSELECTIVES DE COMPOSES PRO-CHIRAUX QUE POUR FAIRE DES REACTIONS D'ESTERIFICATION REGIOSELECTIVES DU GLYCEROL, EN MILIEU ORGANIQUE. L'HEMIHYDROLYSE DES DIESTERS, HYDROXY-3-GLUTARATE DE DIETHYLE ET HYDROXY-3-GLUTARATE D'ETHYLE ET T-BUTYLE, PAR UNE ENZYME INDUSTRIELLE, L'ESTERASE 30.000, EN SYSTEME BIPHASIQUE, CONDUIT A LA SYNTHESE ENANTIOSELECTIVE DES RESPECTFS ACIDES, LE (S)(+)-HYDROXY-3-GLUTARATE D'ETHYLE ET LE (R)()-HYDROXY-3-GLUTARATE DE T-BUTYLE, EN GRANDE QUANTITE ET AVEC UN BON RENDEMENT. DANS LES MEMES CONDITIONS, L'HYDROLYSE SELECTIVE DU METHYL-2-CYCLOPROPANE DICARBOXYLATE DE DIETHYLE, CATALYSEE PAR DEUX ENZYMES, ESTERASE 30.000 ET PLE, DONNE LES ACIDES MONOCARBOXYLIQUES OPTIQUEMENT ACTIFS, (1R, 2S)(+) ET (1S, 2R)() AVEC UN BON RENDEMENT. CES ISOMERES SONT DE PRECURSEURS CHIRAUX DES ACIDES AMINES (1S, 2S)(+) AND (1R, 2R)()-1-AMINO-2-METHYLCYCLOPROPANECARBOXYLIQUE, ME-ACC (NORCORONAMIC ACID), RESPECTIVEMENT. CES AMINO ACIDES PRESENTENT ACTIVITE BIOLOGIQUE ET SONT INTRODUITS DANS DES SEQUENCES PEPTIDIQUES AFIN D'IMPOSER DES CONTRAINTES CONFORMATIONNELLES. UNE METHODE ENZYMATIQUE D'OBTENTION DU 1(3) MONOLAURATE-RAC-GLYCEROL, UN IMPORTANTE AGENT EMULSIONNANT D'INTERET ALIMENTAIRE, EN UTILISANT UNE LIPASE REGIOSELECTIVE COMMERCIALE IMMOBILISEE, LIPOZYME IM, A ETE AUSSI PROPOSEE DANS CE TRAVAIL. EN VUE DE RESOUDRE LE PROBLEME DE SOLUBILITE DU GLYCEROL DANS LE MILIEUX HYDROPHOBE, UN MELANGE DE N-HEXANE / T-BUTANOL (1:1, VOL/VOL) A ETE UTILISE. LES DEUX SUBSTRATS, GLYCEROL ET ACIDE LAURIQUE SONT SOLUBLE DANS CE MILIEUX, EN CONDUISANT A UN SYSTEME MONOPHASIQUE. CE SYSTEME REACTIONNEL PERMET DE TRAVAILLER EN CONTINU. DE FACON A MENER L'ESTERIFICATION DU GLYCEROL DE MANIERE SELECTIVE, UN RAPPORT ELEVE DE GLYCEROL SUR L'ACIDE GRAS A ETE UTILISE.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Exploring science and technology through the Herschel space observatory

Because modern astronomy associates the quest of our origins and high-tech instruments, communicating and teaching astronomy explore both science and technology. We report here on our work in communicating astronomy to the public throughWeb sites (www.herschel.fr), movies on Dailymotion (www.dailymotion.com/AstrophysiqueTV) and new ITC tools that describe interactively the technological dimension of a space mission for astrophysics

Metal recovery from printed circuit boards (PCBs) by acidophilic bioleaching

International audienceDuring bioleaching, the use of bacteria allows the dissolution of metals with markedly reduced amount of reagents and mild pressure and temperature conditions, compared to usual operating conditions. In our study, acidophilic bioleaching was applied to comminuted spent printed circuit boards (PCBs). These wastes contain various metals, including precious and base metals, with concentrations that are generally higher than those found in primary resources. Some studies already demonstrated the efficiency of PCBs bioleaching but significant variations are observed between reported bioleaching rates. In the present study, a double-stage bioreactor has been designed and used in order to bioleach comminuted PCBs in continuous mode. The first stage of the continuous bioreactor was a bubble column in which the acidophilic consortium BRGM-KCC mainly composed of Leptospirillum ferriphilum and Sulfobacillus benefaciens was used to oxidize Fe(II) into Fe(III). The resulting leaching solution was employed to leach the metals contained in PCBs under mechanical stirring in the second stage of the bioreactor. Such a configuration was particularly relevant to reduce the impact of PCBs toxicity on bacterial growth and to maximize bioleaching rates. The culture was able to slowly adapt to PCBs (1% w/v). Consequently , with 48 hours residence time, main metals were dissolved with high yields : 96% Cu, 85% Zn, 73% Ni and 93% Co. When the solid concentration was increased up to 1.8%(w/v), it resulted in higher dissolution rates

Recovery of metals in a double-stage continuous bioreactor for acidic bioleaching of printed circuit boards (PCBs)

International audienceMany studies are now focusing on bioleaching methods to recover metals from WEEE. The efficiency of this process is highly dependent on microorganisms but also on the solid-liquid-gas mass transfer, which is controlled by the reactor design. In this study, bioleaching of comminuted spent printed circuit boards (PCBs) was performed in a stirred tank reactor operated in batch mode and in a double-stage continuous bioreactor. The metal dissolution kinetics were compared. The first stage of the continuous bioreactor was a bubble column in which a BRGM-KCC acidophilic consortium comprising Leptospirillum ferriphilum and Sulfobacillus benefaciens was used to oxidise Fe(II) into Fe(III). The resulting liquor was used to leach out metals contained in PCBs in the second stage of the bioreactor with mechanical stirring. The use of two distinct stages allowed the bacteria to adapt gradually to the PCBs and reach high dissolution yields, i.e. 96% Cu, 73% Ni, 85% Zn and 93% Co when 1% (w/v) PCB scraps were added into the bioleaching reactor, with a hydraulic residence time of 48 hours. By using the double-stage bioreactor, the concentration of PCB scraps could be increased up to 1.8% (w/v) without reducing bioleaching performance. Biomass concentration in the second stage and adaptation of the microorganisms to the toxicity of the metals were sufficient for only the second stage to be used. Under these conditions, the dissolution kinetics were stable, even when iron was provided only by the comminuted PCBs

Recycling-oriented methodology to sample and characterize the metal composition of waste Printed Circuit Boards

International audienceAs spent printed circuit boards (PCBs) are among the most valuable components in waste electrical and electronic equipment (WEEE), their recovery makes economic and strategic sense. However, their composition varies considerably depending on the location, year and type of appliance in which they were used. Developing new treatment processes requires representative sampling of spent PCBs from large samples and accurate determination of their raw material composition. This study aimed to characterize spent PCBs by milling, sampling and leaching with an appropriate reagent. Sampling was performed on 526 kg of spent PCBs, to obtain different samples milled at 750 µm in order to access the metals. The samples were leached with aqua regia and the metal contents of the leachates were determined. For most metals, the analyses of 40 g-samples of spent PCBs showed limited variation in the composition of the different samples. These results concurred well with other studies reported in the literature