The standard frequency spectrum according to regulatory documents is divided into three frequency bands. The third frequency range is currently not well studied and is represented on the standard sound insulation graph by a straight line. When sound is applied to the plate, at a certain frequency, bending waves in the plate are replaced by shear and longitudinal vibrations. Having considered the processes of propagation of shear and longitudinal waves in a soundproof barrier, it is possible to obtain an adequate physical model of wave propagation in the third frequency range, as well as to form an effective method for calculating the sound insulation of air noise. The physical model of sound insulation in the third frequency range is based on the use of objects in wave propagation media with concentrated parameters: coordinates, weight and velocity. The concepts of "concentrated" and "reduced" masses are introduced. Using the law of conservation of the amount of motion and the law of conservation of kinetic energy, formulas are derived for finding sound insulation in the third section of the standard frequency spectrum. The influence of shear waves on the third frequency range of the standard spectrum is considered. Formulas are given for calculating the initial frequency of occurrence of these waves and for finding sound insulation. The regularities of the appearance of the third section of the standard frequency spectrum are determined. The influence of longitudinal waves on the third frequency range is considered. Formulas for finding the limiting frequency, after which longitudinal waves appear in the partition, and formulas for finding sound insulation due to the action of longitudinal waves are obtained. The refinement of the sound insulation formulas using the modulus of elasticity, taking into account the creep of concrete, is shown. A computational experiment is being carried out to calculate sound insulation for building partitions made of heavy concrete of different thicknesses. Examples of graphs for calculating the sound insulation of air noise according to the method under consideration and according to the methodology of regulatory documents are presented.

Keywords: sound insulation of air noise, reduced mass, concentrated mass, method of discrete (concentrated) parameters, longitudinal waves, shear waves

Ensuring road safety a vital issue for many countries, and Russia no exception. To reduce the number of road accidents, you need high-quality and comprehensive investigation to identify the causes and guilty. The article discusses the evaluation of the expert services as a queuing system. The empirical distribution of time intervals between applications for conducting autotechnical expertise.

Keywords: queueing system, distribution, accidents, expert, service applications

Studied mobility planar four-link mechanism of the manipulator in a predetermined area of the workspace. A method for determining the maximum rates for selected destinations for the mechanisms of manipulators with motor redundancy.

Keywords: own properties mechanisms manipulators, mobility manipulators, robots for the synthesis of movement velocity vector

The simulation of the process of the electrically active impurities relocation in the electric field of Schottky diode space charge region has been made. The analysis of the simulation results shows the possibility of controlled alloying impurities relocation on the depth about tens of nanometers caused by electrically active atoms diffusion in the electric field of Schottky diode space charge region.

Keywords: diffusion, space charge region, Schottky diode