In this article, the authors propose two models for BLDC motor winding temperature estimation using machine learning methods. For the purposes of the research, measurements were made for over 160 h of motor operation, and then, they were preprocessed. The algorithms of linear regression, ElasticNet, stochastic gradient descent regressor, support vector machines, decision trees, and AdaBoost were used for predictive modeling. The ability of the models to generalize was achieved by hyperparameter tuning with the use of cross-validation. The conducted research led to promising results of the winding temperature estimation accuracy. In the case of sensorless temperature prediction (model 1), the mean absolute percentage error MAPE was below 4.5% and the coefficient of determination R² was above 0.909. In addition, the extension of the model with the temperature measurement on the casing (model 2) allowed reducing the error value to about 1% and increasing R² to 0.990. The results obtained for the first proposed model show that the overheating protection of the motor can be ensured without direct temperature measurement. In addition, the introduction of a simple casing temperature measurement system allows for an estimation with accuracy suitable for compensating the motor output torque changes related to temperature.

The scope of this article was to find the transient response of the 2G high-temperature superconducting (HTS) tape under alternating overcurrent. The authors performed a series of measurements for the SF12050 HTS tape produced by SuperPower Inc. The tape was fed by a 50-Hz ac voltage source with adjustable amplitude. The temporal dependences of the tape current and voltage drops in each test segment were recorded simultaneously. The measurements were performed for the current amplitudes exceeding the critical value specified by the manufacturer ( I_c = 270 A @77 K, self-field). The instantaneous values of the tape temperature during overcurrent transient period were also determined. Additionally, the numerical analysis of the SF12050 tape was performed. A numerical model was built using PSPICE environment. The model assumes the nonlinear dependence of tape parameters in the function of temperature, as well as the variable cooling conditions during transient state. The constructed model was verified with measurement results.

The COVID-19 pandemic demanded changes in healthcare systems worldwide. The lockdown brought about difficulties in healthcare access. However, trauma still required further attention considering its modifications. The presented study aims to investigate the variances in epidemiological patterns of trauma during the lockdown and the previous year, with a view to better understand the modifications in healthcare provision. The authors analyzed data from the first lockdown in 2020 (12 March–30 May) and the same period in 2019 from 35 hospitals in Lublin Province. A total of 10,806 patients in 2019 and 5212 patients in 2020 were included in the research. The uncovered changes adhered to the total admissions and mortality rate, the frequency of injuries in particular body regions, and injury mechanisms. The lockdown period resulted in a reduction in trauma, requiring an altered approach to healthcare provision. Our research indicates that the altered approach facilitated during such periods is essential for delivering tailored help to trauma patients.

This paper presents the synthesis and physicochemical characterization of a new hybrid composite. Its main goals are evaluating the structure and studying the thermal and mechanical properties of the crosslinked polymeric materials based on varying chemical properties of the compounds. As an organic crosslinking monomer, bisphenol A glycerolate diacrylate (BPA.GDA) was used. Trimethoxyvinylsilane (TMVS) and N-vinyl-2-pyrrolidone (NVP) were used as comonomers and active diluents. The inorganic fraction was the silica in the form of nanoparticles (_NANOSiO₂). The hybrid composites were obtained by the bulk polymerization method using the UV initiator Irqacure 651 with a constant weight ratio of the tetrafunctional monomer BPA.GDA to TMVS or NVP (7:3 wt.%) and different wt.% of silica nanoparticles (0, 1, 3%). The proper course of polymerization was confirmed by the ATR/FTIR spectroscopy and SEM EDAX analysis. In the composites spectra the signals correspond to the C=O groups from NVP at 1672–1675 cm⁻¹, and the vibrations of Si–O–C and Si–O–Si groups at 1053–1100 cm⁻¹ from TMVS and _NANOSiO₂ are visible. Thermal stabilities of the obtained composites were studied by a differential scanning calorimetry DSC. Compared to NVP the samples with TMVS degraded in one stage (422.6–425.3 °C). The NVP-derived materials decomposed in three stages (three endothermic effects on the DSC curves). The addition of _NANOSiO₂ increases the temperature of composites maximum degradation insignificantly. Additionally, the Shore D hardness test was carried out with original metrological measurements of changes in diameter after indentation in relation to the type of material. The accuracy analysis of the obtained test results was based on a comparative analysis of graphical curves obtained from experimental tests. The values of the changes course of similarity in the examined factors, represented by those of characteristic coefficients were determined based on the Fréchet’s theory.

In this paper, the comparison of transient responses of second-generation (2G) high-temperature superconducting (HTS) tapes under alternating overcurrent was presented. The authors performed the series of measurements of the SF4050 and SCS4050 HTS tapes produced by Superpower Co. The measurements were carried out for various amplitudes of current exceeding a critical value given by the manufacturer (I_c = 100 A, dc, @77 K, self-field). Seven measuring probes were soldered to each tape, which allow for simultaneous recording of the supplying current and voltage in each test segment. Tapes were immersed in liquid nitrogen bath under atmospheric pressure and supplied from the 50-Hz voltage source with adjustable amplitude. Numerical models of SF4050 and SCS4050 tapes were build using PSPICE environment. The models assume the nonlinear dependence of tape parameters in the function of temperature and the variable cooling conditions during transient state. The numerical results were compared with the measurements, and good correlation was achieved. Elaborated models allow for the calculation of the overcurrent responses of 2G HTS tapes with and without copper shunts.

Classification of objects in empirical data, especially in biological sciences, is a very complex process and has been a big challenge for researchers who do not specialize in data analysis. Therefore, in this study, we present a comprehensive summary of selected classifiers operating on both exact and fuzzy numbers. The results of performance of specific classifiers are compared on the example of a unique set of empirical data on changes in the behavior of animals in response to environmental factors. This is one of the key challenges in ecological research and it is strictly related to ecosystem changes caused by climate change. Nowadays, changes in behavior are a very popular topic of research because as a result of the COVID-19 pandemic and lower activity of people (lockdown effect). Therefore, various unusual reactions of wild animals were found around the world. A detailed compilation of research results, shortcomings, and strengths of various classification methods may be a compendium of knowledge for biologists and other practitioners as well as researchers working with empirical data.