Controllability of Differential-Algebraic Equations in the Class of Impulse Effects

Considering a control linear system of differential-algebraic equations with infinitely differentiable coefficients we establish the existence of solutions in the class of Sobolev–Schwartz distributions. The solution is expressed as the sum of a regular generalized function and a singular generalized function. We study controllability with a jump of a regular component and a singular component of the solution.     

Hydrodynamic forces acting on a cylinder set in motion abruptly

An attempt has been made to measure directly the forces (drag and lift) that act on a cylinder under the conditions of a fairly complicated unsteady motion in which the velocity is acquired almost instantaneously from the state of rest.     

Effect of molecular structure on dehydrogenation kinetics in the case of C4 and C8 alcohols

Summary The relative adsorption coefficients of ketones are independent of chain length and increase greatly with increased branching of the chain.We express our thanks to A. P. Meshcheryakov for the presentation of 2-ethylhexanol.     

Inertia and drag of cylinders oscillating in a fluid

The results of an experimental investigation of the hydrodynamic forces acting on a circular cylinder oscillating horizontally in water at rest parallel to the free surface are presented. The coefficients of the hydrodynamic forces — the inertia force proportional to the acceleration and the viscous drag proportional to the square of the velocity -are determined. The force coefficients are shown to depend significantly on the dimensionless (divided by the cylinder diameter) amplitude of the oscillations on the interval of variation from 0.5 to 10. In the experiments the maximum values of the Reynolds numbers, calculated from the maximum velocity and the cylinder diameter, were 2.10³–8.10⁴.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 111–115, July–August, 1989.     

The continuous dependence of solutions to algebraic differential systems on the initial data

We consider a nonlinear system of ordinary differential equations which is unsolved with respect to the derivative of the desired vector function and identically degenerate in the definition domain. We study the consistency manifold under assumptions that guarantee the existence of a solution. We prove an analog of the theorem on the continuous dependence of solutions on the initial data, assuming that the latter belong to the consistency manifold.