High-Frequency Method of Removal of Paraffin Plugs in the Equipment of Oil Wells and Oil Pipelines

The processes of heating and melting of paraffin plugs in the shafts of oil wells and in oil pipelines by high-frequency electromagnetic radiation have been investigated. The evolution of the temperature fields in the volume of the plugs has been investigated for various physical conditions and various geometries of the plugs. The times of melting of a through channel in a plug and the times of its complete liquidation have been determined. Unlike the works carried out earlier, elimination of paraffin plugs was investigated with regard for the nonuniformity of the distribution of high-frequency power over the cross section of a plug and the absorption of a high-frequency wave in the metallic walls of a well or a pipeline.     

Low-Temperature Crystal Growth in Aqueous Systems

The conditions for the crystal growth of various substances (salts, amino acids, and others) in aqueous systems between the eutectic (0°C) and room temperatures were studied. The ingots prepared by freezing solutions of required compositions were used as source material for crystal growth (recrystallization). The growth and properties of the crystals were shown to be controlled by the supersaturation which is maintained at the desired level by means of fractional ingot melting.     

Effect of oxide nanofillers on fabrication,structure, and properties of zirconia-based composites

We have studied the effect of NiO on the sintering of yttria-stabilized zirconia at temperatures ranging from 1300 °C to 1500 °C in air and argon environments. It was found that the addition of NiO stabilized the cubic phase of ZrO₂ independently from the sintering atmosphere. The monoclinic phase of ZrO₂ formed only during sintering within the air environment at temperatures higher than 1450 °C. The transformation of NiO to Ni by reversible decomposition depends on the sintering atmosphere, and this can lead to variations in the nature of inclusions and in changes of the structure and properties of nanocomposite materials in the system ZrO₂–NiO(Ni). NiO and Ni inclusions can increase the indentation fracture toughness of zirconia–nickel oxide composite material more than 50%, which can be compared with zirconia ceramics during sintering in a neutral atmosphere alone.     

Heterogeneous catalysis in ionic liquids: The heck reaction of bromobenzene with styrene over palladium supported on mesoporous carbon

Tributylhexylammonium bistriflamide [(C₄H₉)(C₆H₁₃)N][(CF₃SO₂)₂N], an ionic liquid, was used as a solvent for the Heck reaction of bromobenzene with styrene in the presence of Pd deposited onto a mesoporous carbon support. It was found that dibutylamine used as a basic reagent to scavenge hydrogen bromide results in higher conversions of the reactants and higher yields of stilbene than sodium acetate. It was shown that the IL is fully recoverable after use in the catalytic reaction.