The economy of Latvia lags behind economically developed nations approximately fourfold in terms of labour productivity in the tradable sector, which is the key constituent of a modern economy, thereby affecting future sustainable development in the entire country, including the rural areas. The economic backwardness is characteristic of the entire Central and Eastern Europe. This is the heritage of a communist regime that lasted for about half a century and the economic system termed a (centrally) planned economy or a command economy. However, such a term for the communist-period economy is not correct, as it does not represent the purpose it was created for. Accordingly, the paper aims to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU. A planned economy that existed in all communist countries, with the exception of Yugoslavia, was not introduced to contribute to prosperity. It was intended for confrontation or even warfare by the communist countries under the guidance of the USSR against other countries where no communism regime existed, mostly Western world nations with their market economies. For this reason, it is not correct to term it a (centrally) planned economy or a command economy; the right term is a mobilised (war) economy. An extrapolation of a geometric progression for GDP revealed that during the half a century, Latvia as part of the USSR was forced to spend on confrontation with the West not less than EUR 17 bln. (2011 prices) or approximately one gross domestic product of 2011. The research aim of the paper is to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU.

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.