1-kHz table-top ultrashort hard x-ray source for time-resolved x-ray protein

International audienceWe describe a compact, reliable, and high-average-power femtosecond x-ray source and its first application to diffraction on protein crystal. The setup relies on a homemade Ti: sapphire system delivering 12 mJ at a 1 kHz repetition rate, associated with a small vacuum chamber especially designed for laser-plasma interaction and x-ray applications. This device allows the generation of 5×109 photons/s/sr at 8 keV and optimized x-ray irradiation of the studied sample, which can be placed close to the source. We present the diffraction pattern of a protein crystal in a divergent beam geometry, which is a first step to a subpicosecond x-ray diffraction experiment

Characterization of a low current-high voltage air arc discharge at high pressure

http://icpig2007.ipp.cas.cz/files/download/cd-cko/ICPIG2007/pdf/3P10-97.pdfInternational audienc

Plasma assisted fuel reforming for on-board hydrogen rich gas production

Texte disponible en suivant le lien ci-dessous : http://www.cder.dz/A2H2/Medias/Download/Proc%20PDF/PARALLEL%20SESSIONS/%5BS06%5D%20Production%20-%20Hydrocarbons/14-06-06/162.pdfInternational audiencePlasma assisted fuel reforming technology appears particularly attractive for automotive applications, especially regarding compactness, response time and absence of catalyst element. In 2003, Renault and CEP have initiated a research programme on this subject. A test bench allowing reformer feeding with different fuel / air / steam mixtures and coupled with a gas composition analysis system has been especially developed for this application. Preliminary results obtained under partial oxidation condition (H2O/C: 0) have been carried out with unleaded gasoline at atmospheric pressure and around 1500 °C reactor temperature. Under these conditions, a 45 % fuel reforming efficiency was obtained (taking into account the electric power needed to generate the plasma and corresponding to H2 and CO production). Besides, numerical models have allowed a better understanding of the reaction phenomena in the plasma reactor

Optimisation de la géométrie d'une torche plasma pour le réformage de l'essence

International audienceL'hydrogène est potentiellement considéré comme un vecteur énergétique du futur, se substituant aux hydrocarbures liquides actuels. La production d'hydrogène embarquée par exemple pour l'alimentation d'une pile à combustible reste néanmoins un enjeu technologique de taille

Device for generating hydrogen by fuel reforming using electric discharge generating plasma, comprises first cylindrical element within which reactive mixture flows, second element forming electrode tip, and continuous current generator

The hydrogen generating device comprises a first cylindrical element (1) within which a reactive mixture flows, a second element (2) forming an electrode tip (6) arranged along the axis of the first element, and a continuous current generator to establish a potential difference between the elements. The first cylindrical element comprises a conductive area to define with the second element, an area to establish an electrical discharge, a cylindrical electrode (4), and a first cylindrical insulating sleeve (3) closed at the side of the second element. The hydrogen generating device comprises a first cylindrical element (1) within which a reactive mixture flows, a second element (2) forming an electrode tip (6) arranged along the axis of the first element, and a continuous current generator to establish a potential difference between the elements. The first cylindrical element comprises a conductive area to define with the second element, an area to establish an electrical discharge, a cylindrical electrode (4), and a first cylindrical insulating sleeve (3) closed at the side of the second element. A unit for continuously vary the distance between the first conductive area of the first cylindrical element and the second element to vary the length of electric discharge along a flow of the reaction mixture and/or the fuel nature. The cylindrical electrode is mounted within the first insulating sleeve. The cylindrical electrode of the first cylindrical element is rotating along the axis of the first cylindrical element. A second insulating cylindrical sleeve is applied on the inner surface of the cylindrical electrode. The cylindrical electrode is motionless, and the second insulating sleeve is rotating along the axis of the first cylindrical element. A conductive area is delimited by an electrical insulation element. The electrode is stationary, and the second element forming an electrode tip is rotating along its axis. The cylindrical electrode comprises an alternating conductive element and electrically insulating elements along its axis defining a succession of coaxial conducting rings separated from one another. A switching device is able to select the active conducting part, and the other conductive parts are electrically insulated. The movable cylindrical electrode of the first cylindrical element comprises a slit provided for injection of reactive mixture. The slit cut in the cylindrical electrode of the first cylindrical element having a size equal to the flow of cylindrical electrode. The first insulating sleeve comprises a hole provided for the injection of reactive mixture and arranged opposite to the slit. The slits are each cut into the cylindrical electrode against each holes provided in the sleeve. The length of the slits has a size less than the flow of the cylindrical electrode. The holes of the first sleeve are diametrically opposite with respect to the other with respect to the axis of the first cylindrical element. The second element comprises a helical groove, dug in the element such as in insulation. Earth is coupled to the conductive area of the first cylindrical element, or to the pointed electrode of the second element. An independent claim is included for a process for generating hydrogen by fuel reforming

Ethanol and E85 reforming assisted by a non-thermal arc discharge

Conference Information: 10th International Conference on Petroleum Phase Behavior and Fouling, Rio de Janeiro, Brazil, June 2009International audienceEthanol reforming could provide an interesting path for on-board hydrogen production from renewable resources for fuel cell powering. This paper presents a study on hydrogen production from both pure ethanol and E85 with a plasma reactor. Reforming of ethanol was systemically tested with a non-thermal arc discharge system based on a high voltage/low current power source. A short review on ethanol reforming is first presented as a reference point for this study. Effects of supplied power for plasma generation, air/fuel ratio, and addition of water were then experimentally investigated. Those results were at last compared with a 1D multistage model, exhibiting good correlation. In spite of the early stage of research, a fair conversion rate and fair H2 yields have been achieved (90% and 65%, respectively). The optimal conditions for ethanol reforming are found to be at an oxygen ratio higher than the reaction's stoichiometry, with a slight addition of steam. Discussion is provided concerning the non-thermal plasma effect on the ethanol reforming