Вісники та науково-технічні збірники, журнали
Permanent URI for this communityhttps://ena.lpnu.ua/handle/ntb/12
Browse
2 results
Search Results
Item Investigation of rheological properties of a nanocomposite of superparamagnetic iron oxide nanoparticles with polyethylene glycol(Видавництво Львівської політехніки, 2023-02-28) Javanbakht, Taraneh; Concordia UniversityThis paper presents the results of a new investigation of the rheological properties of a nanocomposite of superparamagnetic iron oxide nanoparticles (SPIONs) with polyethylene glycol (PEG). The surface of the nanocomposite had no electrical charge and the SPIONs were coated with the polymer. The investigations were performed at different temperatures and the results were compared on different rheological parameters. The steady-state behavior of samples was observed at 20 °C and 40 °C and a small increase of viscosity versus shear strain, shear rate or time was revealed at 60 °C. Moreover, the shear stress increase was observed with the increase of shear rate and shear strain. The slopes of the corresponding changes were higher at 20 °C and decreased with the increase in temperature. The torque values increased with shear strain and time. The same phenomenon concerning the different slopes at different temperatures was observed for the torque-shear strain and torque-time variations. These results showed that the rheological properties of the nanocomposite depended on the temperature and could change with the temperature increase. An advantage of this study was that the comparative investigation of the rheological properties of nanocomposite at different temperatures was carried out. The other advantage was that the effect of the coating of the SPIONs with the polymer was observed in the obtained results. This new investigation of the nanaocomposite of SPIONs-PEG coated with PEG can provide comparative data for more investigations of the surface charged SPIONs coated with this polymer. These studies can provide information for a further investigation of the effect of the surface charge of SPIONs in the polymeric matrix on their rheological properties.Item Optimization of physical instruments’ characteristics with topsis(Видавництво Львівської політехніки, 2022-02-22) Javanbakht, Taraneh; Concordia University; University of Quebec in MontrealThe present study focuses on the characteristics optimization of the physical instruments with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The hypothesis in this research work was that the characteristics of spectrometers and rheometers could affect their rankings, which in turn could be influenced by the underestimation of their cost criterion. In this paper, the characteristics optimization of the FTIR spectrometers and rheometers was carried out with TOPSIS. Moreover, its modified algorithm was also used in order to analyze the inappropriate consideration of these instruments due to category confusion. The modification of TOPSIS helped obtain an automated decision-making method for the treatment of data. The results showed that the rankings of the FTIR spectrometers and rheometers were different as expected. Moreover, the rankings of the FTIR spectrometers were different with using the unmodified and modified TOPSIS; however, that of the rheometers did not change. The change in the ranking of the FTIR spectrometers was due to the application of the fuzzy disjunction in the TOPSIS code. In this case, the first and second candidates were placed in the first and second positions, respectively, whereas the second candidate had a better rank than the first one in the analysis with the unmodified TOPSIS code. The rank improvement of the first candidate in the category of FTIR spectrometers after the modification of the TOPSIS code was also observed. The results of this work can be used in mechanical engineering and materials science as the appropriate use of instruments in these fields depends on the consideration of their characteristics for which their optimization in comparison with those of other instruments could provide interesting results. Such investigations would provide complementary data for the experimental approaches in further applications.