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

Mathematical models of crystallization of binary metal alloys crystallizing in the temperature range are proposed. These models are intended for use in the composition of quality control systems for cast alloys based on computer thermal analysis. The proposed models make it possible to calculate the time dependences of the relative amounts of the solid and liquid phases using the data of the cooling curve, as well as to determine the intensity of the increase of the amount of the solid phase. The method of determining the temperature dependences of the specific heat and latent crystallization heat using the data on the temperature-concentration dependences of the free energies of the phases forming the system under study was used.

A method is proposed for determining the temperature dependences of thermal effects (the amount of heat released when the temperature changes) based on data on the temperature-concentration dependences of the free energies of the phases of metallic systems. These dependences are necessary for modeling of the processes of crystallization of alloys. They make it possible to obtain temperature dependences of the dimensions of the thermal effects without introducing the results of measurements of direct calorimetry. The peculiarity of calculating of the temperature dependences of thermal effects upon cooling of binary metal systems from the liquid state to room temperature (including crystallization) is shown using the example of the alloy of the system Pb-Sn.

In the paper, the current situation in the production of crop growing by-products in Ukraine is examined. The potential output of crop growing by-products in various regions of Ukraine, part of which could be allocated for energy production, is determined. The fuel properties of the main types of biomass are presented. The state-of-the-art approaches to the use of straw and plant residues in agriculture are analysed. The possible ways of utilising straw and plant residues in crop growing for maintaining and regenerating the fertility of soils, in livestock husbandry as bedding and a supplement to coarse fodders and in heat power industry as an energy source for the production of thermal power are established. The state-of-the-art technologies and machinery for the rational use of straw and plant residues are described. The need for additional research into what plant residues and what quantities of them can be reasonably used for the fertilisation of soils, taking into account the saturation of the crop rotation systems with cereal crops, the limitation of the phytopathogenic load on grain varieties, the development of weeds, the management of the soil’s nitrogen status under different soil and climate conditions.