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This work aims to characterize the effects of pulse repetition rate and flow speed on dielectric barrier discharge (DBD) plasma pulse-to-pulse coupling and its ability to ignite methane-air flows. Experiments are performed on a homemade DBD flow reactor with 5 mm discharge gap. Pressure and equivalence ratio are kept constant at 700 mbar and 0.6. First, we perform high-speed intensified imaging to visualize pulse-to-pulse plasma behavior and ignition kernel development. In air flows, plasma morphology changes from multiple weak filaments to a few stronger filaments indicating plasma pulse-to-pulse coupling. This leads to plasma energy addition in nearly the
same gas volume as the previous discharge. The study performed in methane-air flows highlights the importance of plasma pulse-to-pulse coupling for ignition. We find a critical pulse repetition rate and a minimum number of pulses required to achieve a strong enough coupling to develop a successful ignition kernel. Ignition probability and kernel growth are also evaluated for various conditions. Finally, plasma pulse-to-pulse coupling is quantified by measuring the plasma parameters such as gas temperature and reduced electric field from an optical emission spectroscopy.

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A modified Kagan's amide, N-((S)-1-(3,5-bis(trifluoromethyl)phenyl)ethyl)-3,5dinitrobenzamide [(S)-2] has been designed, synthesized and screened as Chiral Solvating Agent (CSA) for discrimination of optically active substrates. The proposed mode of the action of recognition of chiral isomers of analytes by CSA is based on hydrogen-bonding. The 1 H NMR signals of the two isomers of chiral amides, sulfoxides, α-substituted acids, αhydroxy ketone, epoxy ketone and N-protected amino acids with (S)-2 were well resolved for practical applications of determination of optical purity. The CSA was also screened for detection of separation of signals in 19 F NMR.