Determination of Residual Stresses in Products in Additive Production by the Layer-by-Layer Photopolymerization Method

A computational-experimental model for identifying the residual (shrinkage) stresses arising in parts after their additive manufacturing by the layer-by-layer photopolymerizationmethod is given. The model is based on an analysis of flexible shrinkage strains of a series of specimens shaped as plate-strips with the same parameters but with different polymerization time which is prescribed in their manufacturing on the 3d-printer.     

Effect of the Electrode Radii on the Pump Discharge width and KrF Laser Radiation

Russian Physics Journal - The effect of the electrode shapes on the pump discharge width and the energy of radiation of the KrF laser with pulse duration of 30 ns is investigated by the method of...     

Acoustic field generated by a beam of protons stopping in a water medium

In an experiment with a beam of protons accelerated up to an energy of 200 MeV, the space-time structure of the hydroacoustic field generated by protons stopping in the water medium was observed. The contributions of three components were separated: a cylindrical wave diverging from the middle part of the acoustic antenna and the signals from the ends of the antenna, namely, from the region of the maximal energy density release by protons (the Bragg peak) and from the other end corresponding to the beam entrance into water.     

Stability estimates for linear stochastic systems with deviating argument of neutral type

We study linear stochastic differential equations with deviating argument of neutral type and establish sufficient conditions of stability. The functions determining the initial perturbations of solutions are found.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45, No. 6, pp. 834–842, June, 1993.     

Asymptotics of the solution of an initial-boundary value problem for a singularly perturbed parabolic equation in the case of double root of the degenerate equation

For a singularly perturbed parabolic equation, we construct and justify the asymptotics of the classical solution of an initial-boundary value problem in the case of a double root of the degenerate equation. This case substantially differs from the case of a simple root in that the scales of the boundary layer variables are different.     

Development of the Strategy of Active Control of Instability Waves in Unexcited Turbulent Jets

The possibility of controlling instability waves in the mixing layer of a subsonic unexcited jet is studied. These waves can be noise sources in both free jets and jets as parts of configurations. In the study the method of experimental diagnostics of the instability waves in the near field of a jet using an azimuthal multimicrophone array is realized. The data on the near field fluctuations are used for testing the control strategy proposed by the authors. The strategy consists in narrowband sliding filtration of the original signal and the formation of a narrowband controlling action on the basis of the linear principle of signal superposition. The results of the study represent the next step toward the realization of an active control system suppressing natural instability waves in turbulent jets.