моделювання

The comparative analysis of the most common systems of computer mathematics is made and their structure is described. The main functions of the systems of computer mathematics are determined and benefits and disadvantages of using the systems Derive, Mathematika, Matlab, Mathcad, Maple, MuPad, Gran, GeoGebra are directed. The Ukrainian software tool Gran is described which is used for graphical analysis of functions (Gran1), the systems of geometrical objects on the plane (Gran-2D) and objects in space (Gran-3D).

The article describes the methodological bases of calculation of multiphase transmission lines with distributed parameters of the type of cable lines of high voltage for the analysis of electromagnetic and transient processes in three-phase cable lines. Methods of constructing mathematical model, choice of their structure and calculation of model parameters are shown. An example of the use and research of mathematical model data in the Matlab system.

The results of theoretical studies on the correspondence of the numerical value of the critical density of internal energy to the value of the enthalpy of melting and the structural-energy analogy between the processes of mechanical destruction and melting  are  analyzed. The  physical  picture  of  the  distribution  of  temperature  field  formed  at  the  time  of  the  birth  defect, assuming considered previously investigated defect-free matter and assuming that the temperature redistribution in volume and at the surface  is uniform.

Extraction of glucomannan from crude porang flour by acid hydrolysis and ethanol precipitation was studied. Effects of acid concentration, temperatures and time were investigated, kinetics model of the process was developed and the parameters were evaluated based on experimental data. New data on yield and purity of glucomannan under various conditions were obtained.

For the current financial and economic systems characterized by unstable processes both in behavior and in structure. Causes of global financial instability rooted in imbalances and contradictions of international monetary and financial relations, which creates random perturbation of a different nature and give rise to unstable processes. Instability accompanied usually nonlinearities, which requires the development and application of innovative approaches to modeling processes analyzed.

The article is devoted to modeling and optimization of the rectification unit for the separation of the propylene-propane mixture.

Propene (often known as propylene) is a very important building block for a large number of chemicals, including the addition polymer, poly(propene).

The work presents an algorithm of synthesis of SPICE equivalent circuits for galvanomagnetic sensors based on Hall devices. By means of typical library elements circuits were composed in order to take into account magnetic values and sensor’s orthogonal coordinates that are not supported by SPICE. The obtained modeling results fit the results of experimental investigations and form the basis of the sensor’s calibration procedure.

Accurate evaluation of possible safe operation of thermowells essentially depends on the accuracy of the maximum stresses in them during operation. These stresses are generally determined from simple engineering formulas for bulk of canonical shape, mostly cylindrical shells or beams for the relevant boundary conditions. Thus the general solution is obtained step by step. First the tangential stresses are obtained from relations for cylinder subjected to external pressure.