No abstract

No abstract

No abstract

Centrifugal pumps are being used widely for many applications throughout the world. Lot of work is been carried out on performance improvements, hydraulic vane and volute profiles due to which considerable increase in the efficiency is been observed. It is very difficult to carry out the experimental tests to study the boundary layer behavior and its effect on the performance of the pump. Boundary layer separation plays a very important role in causing the secondary flows in the vane passage which affect the fluid flow path resulting in loss of effective energy transfer to the fluid by vane. Due to the centripetal force acting on the flow due to the curved path of the vane passage, separation of the boundary layer on pressure surface happens well before as compared to the flow separation occurring on the stationary vane surface. At the suction surface the flow is more concentrated hence the flow separation is difficult to occur. In this paper theoretical study of boundary layer behavior on the vane pressure surface is done and separation point is computed to find the occurrence of secondary flows from the separation point. The effect of centripetal force using Dean's equation for velocity distribution over the boundary layer, boundary layer thickness, momentum thickness, displacement thickness and Schlichting's form factor is studied and results are plotted to see the variation of these parameters.

Introduction: Interbracket distance (IBD) plays a key role in load deflection and frictional resistance in the biomechanics of tooth movement. Aim: The aim of this study was to assess the influence of load deflection and friction between the bracket and archwire for a specific load on different bracket designs. Materials and Methods: IBD brackets ( n = 60), Sondhi Mini Uni-Twin brackets ( n = 60), low profile brackets ( n = 60), and Victory conventional brackets ( n = 60) were selected for the study. Load deflection was measured using a universal testing machine on 0.016″ nickel-titanium (NiTi) wire. A universal testing machine was used to measure the frictional resistance on 0.019″ × 0.025″ stainless steel wire. Results: The load deflection of 0.016″ NiTi wire was the highest in IBD followed by Sondhi Mini Uni-Twin, Sondhi conventional, and Victory conventional. Static friction and kinetic friction were the highest in Victory conventional brackets followed by low profile brackets, Sondhi Mini Uni-Twin, and IBD brackets. Conclusions: Load-deflection property will increase with increase in IBD, and frictional resistance will decrease with increase in IBD.