In order to make centrifugal blowers environmentally friendly, machines with a lighter weight and a more compact size are required. Thus, the axial length of the machine needs to be minimized within the diameter limit. However, in the design methodology, losses and thermal study become very significant; thus, losses increase significantly to achieve the desired output power when the volume is excessively reduced. Moreover, due to the machine’s compact size, heat is concentrated rapidly without adequate cooling. It might lead to a temperature rise of the critical part of the machine above the safe limit, such as winding, thereby affecting its lifespan. This study considers the 225 kW high-speed permanent magnet synchronous machine (HSPMSM) with the forced air cooling axial ventilation system (FACAVS) used in centrifugal blower applications. Firstly, four different analytical models (A2–A5) in the electromagnetic analysis are derived by minimizing the initial machine’s (A1) axial length to achieve a lighter weight and more compact size with better electromagnetic performance. The best among analytical models is chosen as the A4 model with a lighter weight and a more compact structure in addition to higher torque density than A1, A2, and A3 models, and higher efficiency than A1, A2, A3, and A5 models by HSPMSM’s, optimal geometric design, and optimal material choice, respectively. Secondly, LPTN is designed to predict the entire analytical model’s thermal behavior in the thermal analysis. Investigation shows that winding temperature rises from the A4 model is maintained below winding insulation by the determined optimal axial ventilation parameters from the sensitivity analysis. Finally, different analytical models are prototyped and tested. The comparisons between predicted electromagnetic performance, winding temperature rise, and test results were carried out, and the results were found to agree with each other consistently.

The elimination of position sensors allows sensorless control to minimizing the size, cost, and additional layers of the permanent magnet synchronous motor (PMSM). In this work, a new flux estimator with an active disturbance rejection controller (ADRC) drift-elimination capability is developed in order to accomplish precise flux estimation. The ESO integrated into the ADRC is capable of detecting and compensating each of the inner model’s fluctuation along with external loads disturbances, enabling a control system with a more effective dynamic response and robust regulations. As a result, the drift issue is greatly mitigated, and the stator flux is accurately predicted throughout a broad range of speeds. The proposed flux observer is validated via sensorless speed vector control of a 15 kW IPMSM motor.

The study evaluates the potential immunocytotoxic effect of aqueous leaf extract of Cassia occidentalis on human peripheral blood mononuclear cells (PBMCs) and Neutrophils. Different concentrations (25 µg/ml, 50 µg/ml, 100 µg/ml) of the extract were prepared. Six millilitres (6ml) of peripheral blood from consented healthy volunteers was collected and PBMCs and neutrophils were isolated on Histopaque media. The viability of PBMCs and neutrophils was determined using trypan blue dye exclusion methods. One-way analysis of variance was used in analysing the results. Total viable cell count (TVCC) for PBMCs and neutrophils yielded 298.9 x 10^4 cells/ml and 327.9 x 10^4 cells/ml respectively. The TVCC of the highest concentration (100 µg/ml) of the extract used for the treatment of PBMCs was 192.7 x 10^4 cells/ml and that of neutrophil was 50.47 x 10^4 cells/ml equivalent to 82.51% and 61.71% mean viability percentages respectively. The PBMCs and neutrophils treated with 25 µg/ml of the extract have the highest mean percentage viability scores of 94.88% and 74.61% respectively. There was a significant difference in the mean percentage viability when control PBMCs was compared with those treated with 100 µg/ml (p<0.0001) and also when control neutrophils was compared with those treated with 25 µg/ml (p=0.02), 50 µg/ml and 100 µg/ml (p<0.0001) respectively. The cell viability tends to decrease in a dose-dependent manner. The aqueous leaf extract of C. occidentalis has a potent cytotoxic effect on both cells, especially at a higher dose. The study recommends an in-depth study to improve the credence of the present study findings.