mathematical model

An universal mathematical model of an induction machine (IM) has been constructed, taking into account the saturation of the main magnetic circuit of its magnetic core and the active power losses.  The proposed approach to IM modeling expands the abilities of MATLAB / Simulink environment for analysis of the electric power supply systems (microgrid in the smart grid) with the nonlinear elements and dynamic load in abnormal, asymmetric and fault regimes.

With an increase of equipment parameters, such as the pressure of the sealing medium and the speed of shaft rotation, the problems  ensuring its hermetization efficiency are rising up.  In addition to hermetization itself, the sealing system affect the overall operational safety of the equipment, especially vibratory.  Groove seals are considered as hydrostatodynamic supports capable of effectively damping rotor oscillations.  To determine the dynamic characteristics, models of grooved seals and single-disc rotors with grooved seals are examined.  The obtained analytical dependences for com

The dissolution process of potassium chloride particles in the apparatus with two-blade mechanical stirrer was investigated and the mass transfer coefficient was determined. The experimental results were generalized by criterion dependence. The independence of the mass transfer coefficient from the solid particles diameter was confirmed. A countercurrent process of potassium salt dissolution in two apparatuses with a mechanical stirring was considered. A mathematical model for countercurrent dissolution was developed and the efficiency of this process was determined.

The process of paraffin formation has been considered, including the peculiarities of the paraffin structure as a result of phase transitions with a decreasing temperature. Mathematical models for thermodynamic and kinetic calculations of the "solid-liquid" system phase equilibrium have been developed. To shift the "fuel oil-paraffin" balance towards the liquid, it is necessary to reduce the activity ratio of solid and liquid phases by introducing into the system a substance with a lower solubility parameter.

The problems of development of united territorial communities, in particular unemployment and economic problems, are considered. Communities, in most cases, lack the resources to address economic and other issues. Therefore, it is necessary to create self-sufficient communities in which there are enough financial instruments for their own development. The mathematical model of the decision support system for the development of territorial communities using the agro-industrial sector was considered.

In the paper, the mathematical model for determination of the region boundary of biaxial elastic states of orthotropic materials is synthesized and the system of nonlinear algebraic equations for identification of its parameters is obtained. Using the continuous method of solution continuation concerning the best parameter and the Runge-Kutta method, the demarcation curves of absolutely elastic and non-elastic deformation regions for pine trees are depicted.

The effect of nitrogen oxides in the presence of sulfur oxide on the absorption of carbon dioxide by chlorophyll – producing microalgae  Chlorella was investigated. Experimental dependences of the dynamics of CO2 uptake by microalgae in the presence of NxOy alone and at the critical concentration of the SO2 photosynthesis inhibitor in the presence of NxOy are presented.