The conditions of nanopores formation in metallic materials during the pulse-periodic laser action were determined. Laser action on two-component Cu-Zn alloy brass L62 was performed with using a CO 2 laser ROFIN DC 010. Laser processing using pulseperiodic radiation with a pulse frequency in the range of 100Hz to 5000 Hz enables the formation of a stable stress state on the sample surface at a temperature that does not exceed the melting point. The structure, containing open pores that fairly evenly distributed over the area, is formed during laser action to the surface of the metallic material. Branched pores with dendrite structure are also formed. The channel type nanopores with a width of ~100 nm were formed under the chosen temperature-rate conditions, creating a nanoporous network. The formation of such structure is realized due to the creation of vacancies and their coagulation as a result of zinc sublimation from the surface of the material. This creates a concentration gradient and promotes diffusion to the surface of the component with relatively high vapour pressure. Measurement of vibration rate of the samples was performed. It was established that regardless of the external laser exposure frequency, the maximum values of the vibration rates of the forced oscillations of samples occur at almost the same frequencies corresponding to their natural oscillation frequencies, under these conditions, nanoporous structures are formed. Damping device application significantly reduces the vibration rate values. In this case the formation of the nanopores in the metallic material does not occur. It is determined that the intensity of formation nanopores in the studied metallic material depends on its vibration characteristics by laser action. The condition of nanopores formation is the presence of significant vibration of the sample.

Technical focus of the research is a discrete throttle valve (DTV) and gas pipeline. An extensive research of vibration and acoustic characteristics of the main pipeline of a gas distribution station was carried out. The acoustic noise power level radiated by the main gas pipeline and it's comparison with the strength criterion were made. The levels of vibration acceleration in different parts of the main gas pipeline were measured. On the basis of experimental data the possible causes of the acousticinduced vibration are described, and measures for reducing vibration loading of a gas pipeline were proposed.

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The noise in natural gas distribution systems is mainly caused by pressure reduction in shut-off and control valves. The aim of present research is to analyze dynamics of an air pressure reducing valve with a muffler installed at its output. An increase of output impedance can lead to a loss in stability and control accuracy. Therefore, the valve simulation model in software package MATLAB/Simulink is developed in order to study the muffler’s impact on static and dynamic performances of the pressure reducing valve. As a result of performed modeling and simulation the influence of the output throttle resistance on the system main operating parameters is obtained. The output data can be used to optimize sizing of the muffler for the air pressure reducing valve.