Vol. 21, No 1, 2017 < Volumes
(ISSN 1428-6394)



hKatarzyna Kaczorowska and Krzysztof Tesch A Short Review of Blood Flow Modelling Methods: from Macro- to Microscales

The aim of this paper it to review various scale approaches to the blood flow modelling. Blood motion may be described by three types of mathematical models according to the observed scales or resolutions, namely microscopic, mesoscopic and macroscopic descriptions. The above approaches are discussed together with their advantages and disadvantages. Several results of mesoscopic simulations are presented with particular attention paid to mesoscale semi-continuum models suitable for real-time blood flow visualisation.


hPaweł Syty and Józef E. Sienkiewicz JMATRIX — Package for Relativistic J-Matrix Calculations in Elastic Scattering of Electrons from Model Potentials

We present a software package JMATRIX1, consisting of two computer codes written in FORTRAN 95 and parallelized with OpenMP, implementing the so-called J-matrix method, applied to elastic scattering of electrons on the radial potential, vanishing faster than the Coulomb potential. In the J-matrix method, the physical scattering problem is replaced by using a well-defined model which is solved analytically. The presented software implements both non-relativistic and relativistic versions of the method, and allows calculations of scattering phase shifts as well as cross sections, in cases when the scattering potential is given through an analytical formula. We performed test calculations for the scattering potential modeled as a truncated Coulomb potential. We show that the numerical phase shifts to converge as we increase the size of the basis used to truncate the scattering potential, and that the method is suitable for calculating the total differential momentum transfer and spin polarization cross sections, using the partial-wave analysis.


hSlawomir Gulkowski Comparison of Single-Diode Models Applied to Thin Film PV Module Operating under Different Environmental Conditions

The electrical current-voltage (I-V) characteristic a of photovoltaic (PV) module depends on the environmental conditions under which it operates. The shape of the I-V curve depends on the solar cell technology and changes dynamically in time with irradiance and temperature. A simulation model of the PV module can be used to examine the dynamic behavior of the I-V curve as well as to extract the module parameters from the curves. This paper presents the results of comparison of two different models based on a single-diode equivalent circuit applied to a thin film module. The MatlabŚimulink simulation studies of I-V characteristic curves in the function of irradiance and temperature were carried out. The results were compared with the experimental data of the I-V curves obtained from outdoor measurements. Relative errors of the simulation and experimental results were analyzed.


hAnna Perelomova Curves of Thermodynamic States in Some Fluids with Dispersion

Variations in the thermodynamic state of a dispersive medium, caused by sound, are studied. A bubbly liquid and a Maxwell fluid are considered as examples. Curves in the plane of thermodynamic states are plotted. They are in fact pictorial images of linear relations of excess pressure and excess density in the acoustic wave which reflect irreversible attenuation of the sound energy. The curves account for the nonlinear generation of the entropy mode in the field of sound. In the case of Maxwell fluids, loops may form under some conditions. Curves and loops for some kinds of stationary waveforms and impulse sound are discussed and compared.


hMykhailo Lytvyn Software for determination of surface tension with sessile drop method

The sessile drop method was implemented to calculate the values of the surface tension coefficient of liquid metals. Appropriate software was developed to increase the data processing efficiency and the accuracy of the obtained results. This paper provides information on the structure and applications of the designed programs as well as the underlying mathematical models used during computations. Since the determination of the surface tension coefficient in this study is based on the recognition of drop outlines from a digital image, the problems of calibration and appropriate photography mode adjustments are mentioned in this paper. In addition, the methods of controlling the research equipment using Arduino shields are described. Finally, the research results are presented in the form of graphs which show the temperature dependence of the studied parameters of metallic samples and compared with the literature data.


The Current Issue