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A method is described for measuring low-energy ignition of combustable mixtures using nanosecond and picosecond laser-induced breakdown. Ignition studies are reported for homogeneous H2/air mixtures. The extent of flame inhibition in H2/air was investigated as a function of CO2 concentration. Our electrodeless spark ignition results are compared with earlier work using electric discharge ignition. A simple model for flame ignition is advanced, based on the temporal and energy density characteristics of the source energy. Implications of laser-induced spark ignition in homogeneous fuel mixtures to the molecular dynamics of flame propagation are discussed.

The switchover from analogue to digital terrestrial television (DTT), expected to be completed in Europe by the end of 2012, will free up a large amount of radio spectrum. This socalled Digital Dividend will provide a unique opportunity to meet the demand for new wireless communications services. In October 2009, the Conference of European Post & Telecommunications Administrations (CEPT) approved a number of band plans and technical conditions for the use of the 790-862 MHz Digital Dividend spectrum by mobile and fixed communications networks. These specifications are sufficiently flexible to allow FDD-only, TDD-only, or mixed frequency arrangements in this band. However, a preferred frequency arrangement based on FDD has been recommended, with the understanding that member states may implement different frequency arrangements with the aim of achieving general interest objectives, ensuring greater efficiency through market-based spectrum management, ensuring greater efficiency when sharing with existing use, or avoiding interference. In this paper we present an overview of the specified band plans and regulatory technical conditions. We also describe the methodologies behind their derivations, and discuss their implications for both DTT services and the new communication networks which will operate in the 790-862 MHz Digital Dividend band.Index Terms-Co-existence analysis, Adjacent-channel interference, Digital Dividend, Spectrum management, Block edge mask, Interference mitigation, WAPECS.978-1-4244-5188-3/10/$26.00 ©2010 IEEE This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the IEEE DySPAN 2010 proceedings

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Techniques based on picosecond resonance-enhanced multiphoton ionization and mass-selective ion photodissociation are described as a means for studying complex reaction mechanisms in molecular clusters. A set of experiments is described that can identify the cluster-size specific reactions that occur by the overlapping processes of neutral dissociation/fragment ionization, parent ionization/dissociation, and parent ion photoexcitation/dissociation. These molecular beam techniques are demonstrated for the case of neutral and ionic photon transfer and evaporation in clusters of phenol in (NH(3))(n), as well for radical chemistry and van der Waals dissociation in (CH(3)I) (n) clusters.