# mathematical model

## Mathematical Model of Magnetic State of Permanent Magnet Direct Current Motor

There is a tendency of replacement of small direct current motors with electromagnetic excitation on permanent magnet direct current (PMDC) motors nowadays. PMDC motors are widely used and that is why a task of creation of mathematical models of this type of motor is actual. The aim of the article is creation of mathematical model of magnetic state of PMDC motors on the basis of theory of electric and magnetic circuit.

## ANALYSIS OF THE ENVIRONMENTAL IMPACT OF UNSORTED CULLET

Prediction of cullet accumulation at municipal solid waste landfills was carried out by linear and multiple re-gression methods. Over time, the amount of waste at the landfills will increase and the soil condition will dete-riorate due to Na+ leaching This is confirmed by the experimental study of leaching of sodium ions from the cullet surface of different fractions with pure water and solutions with pH = 4.8 and pH = 9.2.

## INVESTIGATION OF THE IMPACT OF PHOSPHORUS OXIDE ON THE CARBON DIOXIDE UPTAKE RATE BY CHLOROPHYLL-PRODUCING MICROALGAE

One of the most important ecological problems of the XXI century is the change in the global climate. Over the past decade, as a result of human activity, the concentration of gases forming the greenhouse effect in the atmosphere is increasing. This leads to devastating consequences for the planet Earth and makes the problem of climate change one of the most important in the field of environmental protection.

## Development of mathematical model of ball mill on the basis of the obtained experimental data

Aim. Experimental study of main technological parameters of a ball mill during coal milling at a thermal power plant and development of a mathematical model for the mill on the basis of the obtained data. Method. Based on the analysis of the energy flows in the ball mill the relation between the vibration energy of the mill body and the amount of the material in the mill is defined. Experimental study, i.e.

## Simulation of Switching Processes in Lines Extra-high Voltage 750 Kv

Mathematical and digital models to study the long line switching processes with regard to their basic parameters are developed, providing the required adequate modeling.

## Modeling Synchronous Machines Overexitation Limiters to Analyze Power System Stability

This article surveys the modeling aspects of modern excitation systems for synchronous machines that is used to analyze power system stability. We presented peculiarities of over excitation limiter mathematical model and tested their performance for real power stations.

## Computer-Aided System for Monitoring and Planning of Actions to Increase Machine-Building Enterprises Energy Efficiency

The article describes mathematical model of analyses the energy use costs efficiency (depending on the type and volume of products produced by the machine-building enterprise, the consumption of certain types of energy resources and their use in specific production processes, etc.). Methodology and mathematical model of the plan for modernization of industrial production energy-consuming processes has been developed.

## Application of Liquid Extraction for Treatment of Wastewater from Edible Oils Production

The structure of an emulsion formed in wastewater from edible oils production has been investigated. The type of emulsifier has been determined and the method of emulsion destruction has been proposed, providing further quality treatment of wastewater via liquid-extraction method. The resulting equilibrium and operating lines of the process were received. The number of transfer stages has been determined. The mathematical model of liquid-extraction wastewater treatment was built.

## MATHEMATICAL MODEL OF PROCESSES FOR THE PROVISION OF MEDICAL SERVICES

Quality  and  efficiency  of medical  services  are  the major priorities  in  the development of health  care  system within the world countries. With the civilization development the quality of the medical services acquires a key value.