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The ability of Horizontal & Vertical Axis Wind Turbine (HAWT & VAWT) to harness the incoming wind is limited due to several factors such as structural constrains, fatigue problems, geographical and ecological issues, noise pollution, vibrational & acoustic losses. Diffuser Augmented Wind Turbine (DAWT) exploits the concepts of velocity augmentation to maximize power production efficiently when compared to conventional approach. The optimization of the geometric parameters can help the augmentation capability of the diffuser. This study investigates the aerodynamic effect of slits on diffuser casings and the performance of slotted and non-slotted diffuser casings is compared using 3D CFD analysis and validated experimentally. The performance of the studied diffusers is analysed in terms of velocity at the rotor plane, augmentation ratio, and swallowed mass flow rate. At tip speed corresponding to 62 m/s, the performance parameters of slotted DAWTs showed an increase by 27.4% and 46.8% compared to non-slotted DAWTs and open turbines, respectively. It is also observed that the inclusion of slotted and non-slotted diffusers enclosing the rotor resulted in an average augmentation of 2.01 and 1.36 in both power and torque produced, respectively. Submitted/Accepted version This work was supported & funded by MAHE-SPSB and the Department of Aeronautical & Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Karnataka, India.

Background and objective The hip joint is the vital joint that is responsible for the bodyweight transfer from the upper body to the lower body. Due to age these joints are worn out and need to be replaced by artificial hip implants. Wear is the predominant factor that is responsible for the loosening of hip implants. The wear occurs between the joints due to various reasons. The wear estimation at the design stage gives a clear idea about the life of the implants and also minor changes in the design may also significantly increase the life expectancy of the implant which can further reduce the rate of revision surgery. The linear wear rate is estimated in the taper trunnion surface. Methods In this study, the circular and trapezoidal-shaped stem implant is designed, and wear studies are performed at the trunnion junction. The femoral head of size 28 mm, acetabular cup thickness of 4 mm, and a backing cup of thickness 2 mm are considered for the study. The neck taper radiuses at the top surface are altered. Ansys is used to perform the simulations. Results At the time of assembly of the femoral head into the stem, the stresses were found to be increasing with an increase in the top surface radius of the neck taper junctions. However, when the walking conditions are considered for wear estimation of implants the circular implants with the 12/14 mm taper exhibited the lesser linear wear rate of 0.003 mm/year. The trapezoidal implants with the 10/14 mm taper exhibited a lesser linear wear rate of 0.032 mm/year. Conclusions Wear is an important parameter that leads to the revision of implants due to loosening. It is found that with the decrease in the taper radius at the top surface against the standard 12/14 mm taper there is no significant decrease in the wear rate at the taper junction. Overall the circular implants exhibited less wear rate results over the trapezoidal-shaped stem implants. Due to the less linear wear rate, the circular implant has a higher life over the trapezoidal-shaped implant. Further, these implants can be manufactured to test using a hip simulator with the same conditions to validate the obtained results.