This thesis describes development of a new actuator technology for integrated machines of the future: piezoelectric ultrasonic micromotors. Ultrasonic motors o er the advantages of low speed, high torque operation without the need for gears. They can be made compact and lightweight and provide a holding torque in the absence of applied power due to the traveling wave frictional coupling mechani...

All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the dynamics of human RPA (hRPA) activity on topologically constrained dsDNA with single-molecule magnetic t...

This paper develops a high dynamic and robust speed-torque control system for servo drives based on adaptive observer and self-tuning techniques with on-line inertia identification. Only the rotor position is measured even for a low precision shaft encoder. The instantaneous speed and the disturbance torque are accurately estimated by an extended Luenberger observer inertia adaptive. A current ...

We discuss non-ideal torque control in wind turbine systems (WTS). Most high-level controllers generate a reference torque which is then send to the underlying electrical drive system (generator+inverter) of the WTS to steer the turbine/generator to its optimal operation point (depending on the wind speed). The energy production heavily depends on the mechanical power (i.e. the product of rotat...

This study investigated the influence of cross-section profile on the mechanical behaviors of six commercial nickel-titanium (NiTi) root canal instruments using the finite element method. The nonlinear mechanical characteristics of the NiTi alloy were taken into account. The six root canal instruments studied were ProTaper, Hero642, Mtwo, ProFile, Quantec, and NiTiflex. Mathematical models for ...

Since the conventional electro-mechanical converter of 2D valve had problems of step lose due to its small tooth-pitch angle, a novel rotary electromagnet with large tooth-pitch angle and coreless rotor structure was proposed. Combined with the approaches of magnetic circuit analysis, finite element simulation and experimental study, the static and dynamic characteristics of electromagnet inclu...

OBJECTIVE To evaluate the influence of pilot hole tapping on pullout resistance and insertion torque of pedicle screws with a conical core. METHODS Mechanical tests using a universal testing machine were performed on pedicle screws with a conical core that were inserted into pedicles in the fifth lumbar vertebra of calves. The insertion torque was measured using a torque meter with a capacity...