This paper presents an analysis of use of ultrasonic standing wave in cell separation from bodily fluids based on the example of erythrocyte separation from plasma. It describes movement of red blood cells in plasma under the influence of the acoustic field (whose forces result from interaction of red blood cells with plasma as the vibrating medium) and under the influence of resistance forces in Stokes’ and Oseen’s approximation. The general properties of solutions of the motion equation are given. The solutions for the parameters of the ultrasonic wave and blood cells which are interesting in terms of practical applications in medical diagnostics are discussed. Time constants of the cell transportation to the regions of stable equilibrium in the field of ultrasonic standing wave are estimated. The formulas which determine the time needed to obtain the assumed concentration increase in plasma in nodes and/or anti-nodes of the standing wave are derived.

The article presents the results of research on selected thermal, mechanical properties, as well as the microscopic structure of filaments and details made on a 3D printer in FDM technology. The materials used in the study were PETG (polyethylene terephthalate doped with glycol) and PLA (polylactide) doped with copper. As part of the study, Differential Scanning Calorimetry (DSC) was performed in order to determine the temperatures of phase transformations and changes in melting enthalpy values of filaments before the printing process and also elements made of them. The second part of the research was electrocorrosive ageing process of printouts, carried out in the Simulated Body Fluid solution in a device generating 0.3 A direct current, voltage with value 4.3 V for the entire duration of the test, which was 720 h. After this process DSC test was conducted again. The next stage of the research was Dynamic Mechanical Analysis (DMA) of printouts before and after electrocorrosive ageing process. This test was carried out to characterize the dynamic-mechanical properties as a function of frequency, temperature and time. Additionally, microscopic analyses of the surfaces of the tested printouts were performed in order to assess the changes after electrolysis.