International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The use of renewable sources for energy purposes is very important from the global environmental perspective. Biomass is part of this group of fuels. This article focuses on the characteristics of wet biomass, a typical fuel source in the Albanian rural areas and not only. Thus, the most significant factor of biomass combustion is its moisture content in natural conditions. This property significantly influences the burning quality of biomass. Drying of this fuel using conventional methods or energy intensity processes aims to decrease the moisture content in biomass and meantime increase of its calorific value. The techniques of drying wet biomass vary significantly. Energy utilization of wet biomass is the main goal of this paper, considering it an important fuel source especially during winter season in Albanian rural areas. The variation of heating value to moisture content and other significant parameters have been investigated.

This article describes a method for producing composite materials based on polytetrafluoroethylene with high performance properties. One of the obstacles to achieve this result had been the accumulation of moisture in the semi-finished product, which subsequently led to the appearance of defects in products made of fluorine composites. It is proposed to produce semi-finished preforms under reduced specific pressure, in which the moisture content is easier, cheaper and more efficient to control than with the current technological regulations. It is shown that the use of these semi-finished preforms allows getting almost defect-free products with high performance characteristics.

Soil water retention and soil compaction are very important factors in the plant production and environment protection. The field investigations of the variation of soil moisture and soil density of Luvisol loamy sand in arable layer and in hard pen during sugar beet growing season in conventional tillage with implementation of mineral and organic fertilization were realised. In the growing season the soil moisture extremely fluctuates in the range from 4 to 18%. At the same time, it causes fluctuations of soil density, which totally decreases in time. Starting from June one can observe that the natural changes of the soil moisture cause contrary changes of soil density. Mostly, the soil moisture and soil density variation during growing season are similar in ruts and at the field besides the ruts. Generally, the organic fertilization increases the soil retention to about 4 % in arable layer and profitable enhance the loosened action of water.

Methods for calculating the nonequilibrium phase transformations during the condensation of supercooled steam in the turbine flow path are developed. In the process of realization, the development of the classical Zel’dovich-Frenckel’s theory for the case of nonstationary nucleation of a new phase with fast extensions of supercooled steam is considered. A numerical-analytical method for calculating condensation was designed and implemented in the form of a software package, which consistently takes into account the nonstationarity of the process. Numerical studies have shown high efficiency and accuracy of the method.