The relationship between current and channel diameter of 30 cm long laboratory sparks

In this study the dependence of channel diameter of 30 cm long sparks on discharge current is analyzed using a photographic technique. The results show the radial channel intensity variation follows a Gaussian distribution. The channel diameter (D), defined as the width of the intensity profile at 10% level, increases with the increasing peak current (I_p) up to 3 kA. The relationship between the two parameters can be represented by the equation, D = 8.36 ln(I_p) + 1.598, where D is in mm and I_p is in kA. The experimental results agree reasonably well with the available theory.     

From Iron to Copper: The Effect of Transition Metal Catalysts on the Hydrogen Storage Properties of Nanoconfined LiBH4 in a Graphene-Rich N-Doped Matrix

Incipient wetness impregnation was employed to decorate two N-doped graphene-rich matrixes with iron, nickel, cobalt, and copper nanoparticles. The N-doped matrix was wetted with methanol solutions of the corresponding nitrates. After agitation and solvent evaporation, reduction at 800 °C over the carbon matrix promoted the formation of nanoparticles. The mass of the metal fraction was limited to 5 wt. % to determine if limited quantities of metallic nanoparticles catalyze the hydrogen capture/release of nanoconfined LiBH₄. Isotherms of nitrogen adsorption afforded the textural characterization of the matrixes. Electronic microscopy displayed particles of definite size, evenly distributed on the matrixes, as confirmed by X-ray diffraction. The same techniques assessed the impact of LiBH₄ 50 vol. % impregnation on nanoparticle distribution and size. The hydrogen storage properties of these materials were evaluated by differential scanning calorimetry and two cycles of volumetric studies. X-ray diffraction allowed us to follow the evolution of the material after two cycles of hydrogen capture-release. We discuss if limited quantities of coordination metals can improve the hydrogen storage properties of nanoconfined LiBH₄, and which critical parameters might restrain the synergies between nanoconfinement and the presence of metal catalysts.     

ChemInform Abstract: Stabilization of the Pseudo-Benzene N6 Ring with Oxygen.

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