This paper investigates the application of a three-level T-type inverter for driving a dual star induction machine (DSIM). This study investigates the performance of a DSIM driven by a three-level T-type inverter, comparing different Pulse Width Modulation (PWM) strategies. A comparative analysis is conducted against a conventional two-level inverter with standard PWM to assess performance differences. Key evaluation criteria, such as efficiency, control precision, and harmonic distortion, are analyzed to determine the benefits of the threelevel T-type inverter. The results demonstrate the superior performance of the three-level T-type inverter, highlighting its potential to enhance DSIM efficiency and operational effectiveness in practical applications.
Fiber-based sorbents play a critical role in oil sorption applications, thus minimizing ecological harm. Polylactic acid fibers were produced by electrospinning, centrifugal spinning, and porous fiber-based sorbents were produced by Material Extrusion Fused Deposition Modeling 3D printing. The fiber-producing processes were optimized based on the electrical conductivity, solution viscosity and surface tension measurements of the solutions. Beadfree fibers (d=0.82±0.15 μm) were produced with electrospinning, however beaded fibers (d=6.45±3.71 μm) formed during centrifugal spinning. Oil sorption results show 94.05±22.64 g/g for electrospun and 30.53±0.73 g/g for centrifugally spun fiber mats, whereas 3D printed sorbents indicate 2.05 g/g.
This paper focuses on a new investigation of the rheological properties of a blend of polyacrylic acid (PAA) and polyvinyl alcohol (PVA). The hypothesis in this work was that the rheological properties of PVA in the blend containing PAA could be comparable with those of the pure PVA. The viscosity of the blend, both moduli, normal force and torque were investigated. The complex viscosity showed a linear increase, whereas the shear stress represented a nonlinear and much bigger increase. The results of this investigation on the blend of PAA and PVA can be used in holographic recording and material coating.
This paper deals with a generalized model of the cosine generating rack and the generated reciprocate meshing tooth flanks. The generating rack was generalized by setting the pitch of the rack constant, while other parameters like pitch line pressure angle and cosine amplitude can change. Here we consider the pressure angle the main parameter which will determine the amplitude of the cosine function. The equations of meshing were determined for a compensated gear pair. The contact line shape was determined using the Mathcad environment. The model of the relative sliding of the profiles is based on the contact line. The numerical case study serves as the basis for the conclusions drawn.
This study numerically investigates the effects of steady blowing on a NACA 0015 airfoil to control flow separation and enhance aerodynamic performance across a range of angles of attack. CFD simulations were performed at Re = 6×105 using the standard k − ε turbulence model, showing good agreement with previous experimental and numerical studies. The influence of injection location was assessed at x/c = 0.00 and x/c = 0.17. Leading-edge injection (x/c = 0.00) was found most effective in increasing lift and delaying separation at moderate AoA (3°–11°), yielding the highest lift-to-drag ratios. Injection at x/c = 0.17 slightly reduces drag at zero incidence. At higher AoA (≥12°), both injection positions increase drag and reduce CL /CD, indicating that excessive injection can intensify separation. The results demonstrate that properly positioned injection can significantly improve aerodynamic efficiency, with leading-edge injection being optimal for practical operation.
