Joel Pacheco

L-edge inner shell spectroscopy of nanostructured Fe3O4

Abstract We have measured magnetic circular dichroism at the Fe L edge in samples of colloidal Fe 3 O 4 and in Fe 3 O 4 powder. The results for the colloid can be interpreted in terms of the model presented by Sette et al. for the dichroism of bulk Fe 3 O 4 . We notice a shift in the position of the Fe L 3 line in the colloid with regard to the powder, which is however in the opposite direction as expected for a cluster. We observe a new structure in the dichroism of the colloid spectrum that could be cluster-specific, in spite of the fact that, for the cluster size of our colloids, the fraction of atoms at the surface of the cluster is not large.

Hydrogen production from methane conversion in a gliding arc

Until now, the major problem of methane conversion is to break the very strong C-H bond. It is possible by employing some catalytic methods. However, the formation of carbon powder diminishes the catalytic performance. The use of a gliding arc, described in this work, has two objectives: the hydrogen production and other syngas such as acetylene, and the treatment of the green house gas methane. A good approximation model describing the chemical processes concerning the methane decomposition is described, first by the interaction of key radicals such as CH3 and H, followed by chemical reactions involving other hydrocarbons. Furthermore, the experimental results demonstrated the ability of the gliding arc to accelerate chemical reactions at low temperatures while decreasing energetic cost.

Warm Plasma Reactor With Vortex Effect Enhanced Used for CH 4 –CO 2 Reforming

This paper provides a simple manner to demonstrate the vortex effect, occurring inside a plasma reactor operating at atmospheric pressure, used for CH4 and CO2 reforming and their conversion to high added value products. The reactor has a specific design to preheat the incoming gas and, at the same time, to cool the reactor bulk. The trace printed on the conical electrode and in the reactor bottom represents a clearly manifestation of the vortex effect. The reactor is also provided with a postchamber to prevent environment reaction and get an expansion in plasma volume sustaining a stable discharge operation.

Synthesis of Carbon Nanofibers by a Glow-Arc Discharge

The carbon nanofibers (CNF) consist of graphite platelets arranged in diverse orientations with respect to the fiber axis and present distinctive and special functional properties; these structures have a large number of edges and remarked chemical interaction that favor the absorption capacity [1], they also have a high-catalytic activity which can be used as solid carbon supports for other catalytic reactions [2], [3]. Because all these remarkable features, CNF are quite appropriate for health [4,5] and atmospheric pollutants treatment [6-8], on-chip interconnect integration [9,10] and they can also be used like chemical or biochemical sensing on molecular scale [11] . To appreciate, a little bit more, the vast world of carbon nanostructures, M.Monthioux and V. Kuznetsov describe, from a carefully point of view [12], some amazing data about the history of carbon nanostructures; in particular they mention a patent of