Experimental Study of Methane-Oxygen Flames Doped with Nitrogen Oxide or Ammonia. Comparison with Modeling

International audienceNH3 and NO have been added to low pressure, premixed laminar CH4-O2 flames of different equivalence ratios. The profiles of concentrations of major radicals and stable species have been obtained, using a molecular beam sampling technique coupled with a mass spectrometer. Laser-induced fluorescence has been used to measure CH radicals. Absorption spectroscopy has been applied to OH radical and temperature measurements. The behaviours of NO and HCN are mainly discussed, and the whole experimental result compared to complete flame structure computations. Using a recent reaction mechanism described by Miller, we notice that pollutants NO and HCN are generally underestimated by computations. Another mechanism, proposed by Bian et al., for nitrogen oxidation has been tested. Sensitivity and reaction path analysis made it possible to identify the reactions which would require modifications, according to a review of recently published kinetic values, in order to get a better fit between the experimental profiles and the computed ones

The DNA sequence and comparative analysis of human chromosome 5

Chromosome 5 is one of the largest human chromosomes yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-encoding genes including the protocadherin and interleukin gene families and the first complete versions of each of the large chromosome 5 specific internal duplications. These duplications are very recent evolutionary events and play a likely mechanistic role, since deletions of these regions are the cause of debilitating disorders including spinal muscular atrophy (SMA)