Averaging of Nonlinear Oscillation Systems of Higher Approximation with Delay

For oscillation resonance systems with delay on a finite segment or a semiaxis, we justify the averaging method with respect to fast variables. We also obtain error estimates for this method, which explicitly depend on a small parameter.     

Structure and Magnetoresistance of Co–Gd and Al–Co–Gd Alloy Films

Technical Physics - Structural data and dependences of the film resistance on magnetic field strength R(H) are presented for Co–Gd and Al–Co–Gd alloy films obtained by vacuum...     

Method of delivery of methane from seafloor deposits of solid hydrates to the surface

A model of the process of methane delivery from seafloor deposits of solid hydrates to the surface has been developed and approved. The model considers methane delivery through a vertical pipe lowered from the sea surface to the seafloor deposit. The model allows to determine important characteristics of the flow through the pipe—the possibility of stationary self-sustained flow of the medium to the surface; the gushing character of the flow; medium velocity, pressure, and composition distribution along the pipe—and thus to optimize the process of gas production.     

Thermal ignition of a heterogeneous system in a stirring semibatch reactor

The thermal ignition of a heterogeneous two-phase system of two immiscible liquids in a stirring semibatch reactor was modeled. The model took into account the dispersion of one phase in the other, the mass transfer of a reagent from the disperse phase into the dispersion medium, and the bimolecular exothermal reaction that occurred in the latter. The kinetic dependences of reagent concentrations, the dynamics of reactor heating, and the critical conditions of thermal ignition were studied. It was found that the initial temperature of the reactor had a considerable effect on its dynamic behavior.     

Allobetulin Ring A Contraction Effected by Sulfur Diethylaminotrifluoride

Russian Journal of General Chemistry - The action of sulfur diethylaminotrifluoride on 19β,28-epoxyoleanan-3-ol (allobetulin) causes dehydration of the terpenoid and isomerization of the ring...