The article presents an analysis of known developments on creation of sieve-less pneumatic vibration centrifuges separating devices and processes of separating seed mixtures into fractions according to the complex of physical and mechanical properties of components. Mechanistic and mathematical models for studying the movement of particles over the sieve-free surface of pneumatic vibration separators were developed, theoretical studies of movement of seed mixture components were conducted and the most acceptable pneumatic vibration centrifugation process was determined by likeness to the process occurring on the separating surface of pneumatic sorting tables. To achieve the greatest separation of particles on the complex of their physical and mechanical properties (density, geometric dimensions, aerodynamic properties of seeds) is possible with the same direction of oscillatory motion and rotation of the separating surface performing the rotation in the direction from a larger radius to a smaller radius of the surface, in the “fluidization” mode, i. e. i.e. with periodic separation of the lower particles of the layer from the separating surface at simultaneous blowing of the layer by an air stream.

It is well known that wood tends to shrink and swell as the relative humidity of the air changes. There have been, and still are, attempts to make dimensionally stable wood panels such as Dendrolight®. The physical-mechanical, operational, including acoustic, properties of this material have been significantly improved compared to traditional wood-based panels. However, the production of this material requires very specific processing equipment and a large energy investment. The developers of this material in Latvia invented and patented wood, Lightweight Stabilised Blockboard (LSB). In order for this material to be used in the production of various products, it is necessary to clarify its characteristic, technological, as well as operational properties. The study gathers information about the sound absorption properties of various natural and wood materials, characteristics, and the sound absorption of the studied material at different sound frequencies. The reviewed sources of information indicate that nowadays there are still problems in sound conduction and absorption and isolation issues are being addressed in building acoustics. The production of samples and the determination of sound absorption were carried out using a developed methodology developed in accordance with regulatory requirements. The data obtained in the practical study were compared with the relevant indicators of the Dendrolight® and wood-based panels used for building structures and to determine their compliance with the requirements set forth in the standards ISO 10534-2 and ISO 11654. Research data show that LSB corresponds to E sound absorption class in some of the investigated frequencies.