Nanocrystals of stable, tetragonal tin dioxide have been synthesized using microwave processing, and the effect of microwave heating on the structural phase transformations of the tin compounds...

The efficiency of annular-nozzle ejectors serving as components of complex technical systems interacting with high-temperature media in engines and in the field of energy technologies is not linearly related to the gas-dynamic characteristics of the flows formed in the device. In this paper, we have analyzed the results of numerical and experimental studies of gas jets in an annular-nozzle air ejector. The regression equations built according to the circumscribed central composite design described the relationship between a pressure drop and the structural parameters of the nozzle with the speed and mass flow rates of the airflows, including error rates of no more than 15 percent. A two-factor optimization based on Harington’s generalized desirability function was performed to obtain a relatively accurate estimate of the ejector efficiency under the influence of the structural and operating parameters. An optimization method based on the combination of response surface methodology and the desirability function approach, allowing simultaneous consideration of all responses, made it possible to simultaneously optimize multiple conflicting objectives.

Catalytic activity of oxide nanostructure catalysts fixed on the surface of polymeric carrying agents was studied in relation to the removal of organic substances difficultly decomposed by the...

Using electronic spectroscopy and fluorescence techniques, the degradation of 2-methyl-4-chlorophenoxyacetic acid has been researched in water under the excitation with UV radiation produced by a KrCl excimer lamp in the presence of “TiO₂, SnO₂, SnO₂/TiO₂ Nanoparticles – Polypropylene Fibrous Carrier” Systems. It has been determined that MCPA phototransformation is most efficient when using the “TiO₂/SnO₂ heteronanoparticles – carrier” system with the concentration of 25/6 mg/g. The results indicate that systems with applied semiconductor particles do not exhibit sorption properties towards МСРА molecules. Therefore, the change in the spectral characteristics of a МСРА water solution after time-exposure and exposure to radiation is only associated with the phototransformations of non-adsorbed МСРА molecules and with the emergence of their photodegradation products.