A mathematical model of ammonia oxidation on a platinoid catalyst, taking into account the N 2 O formation, was developed. The possibilities of lowering the amount of N 2 O, which is formed as by-product in high-temperature oxidation of ammonia in nitric acid production, are examined. The developed model allows calculation of the reactor for ammonia oxidation using platinoid catalysts of different geometric profi les.

The substructure evolution was observed in the range of scales from dozens nanometers to millimeters on the surface of the aluminum single crystalline plates under restricted cyclic tension. The self-similar systems of crossing bands that create the grid-like ordered structures on different scales are assumed to be clear manifestation of their self-organization. The selforganization of these grid-like structures is assumed to be inevitably related to the crystal structure defects (dislocations, point-like defects and their ensembles). The model is proposed for explanation of 2-dimensional rectangular "tweed" and 3-dimensional rhombic "pullover" pattern formations which are related to cooperative arrangement of crystal structure defects.

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