Hydraulic actuators have high power-to-weight ratios, making them suitable for high-power robotic applications such as in walking robots and construction machines. However, large frictional forces in hydraulic actuators, rotary hydraulic actuators in particular, degrade the control performance. To suppress frictional forces and increase robustness against modeling errors, this study considered ...

OBJECTIVES To investigate the static frictional resistance at the bracket/archwire interface in two recently introduced bracket systems and compare them to conventional ceramic and conventional metal bracket systems. Three variables were considered including the bracket system, archwire type and archwire angulation. MATERIAL AND METHODS Four bracket systems were tested in vitro: Self ligating...

The interplay between local mechanical strain energy and lateral frictional forces determines the shape of carbon nanotubes on substrates. In turn, because of its nanometer-size diameter, the shape of a carbon nanotube strongly influences its local electronic, chemical, and mechanical properties. Few, if any, methods exist for resolving the strain energy and static frictional forces along the l...

A simple model is developed that predicts the coefficient of rolling friction for an undriven laboratory cart on a track that is approximately independent of the mass loaded onto the cart and of the angle of inclination of the track. The model includes both deformation of the wheels/track and frictional torque at the axles/bearings. The concept of rolling friction is contrasted with the static ...

one of the main factors that cause to quality loss for fresh fruit market apples is bruise damage. amongst the factors that affect apple sensitivity to bruising, major one is drop height and area profile during the impact. in the present study, four iranian apple varieties consisted of atirli, kapak, kowse and paiez that were selected and 100 fruits of each variety were picked up, then apples w...

Theoretical study of non-Newtonian effects of second-order fluids on the performance characteristics of inclined slider bearings is presented. An approximate method is used for the solution of the highly nonlinear momentum equations for the second-order fluids. The closed form expressions for the fluid film pressure, load carrying capacity, frictional force, coefficient of friction, and centre ...

OBJECTIVE The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. METHODS 0.016-inch nickel titanium (NiTi) wires and 0.017 × 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0°, 5°, and 10°. Upp...

Abst-ract constraint. A static grasp occurs, for example, if a cube is grasped in a frictional parallel-jaw gripper, since the frictional forces must be included to verify stability. A quasi-static grasp might correspond to pushing a sofa across the floor-the sofa retains contact with the effector to balance the forces of sliding This paper' describes some preliminary work on dynamic manipulati...

With the advancement of the field of biotribology, considerable interest has arisen in the study of cell and tissue frictional properties. From the perspective of medical device development, the frictional properties between a rigid surface and underlying cells and tissues are of a particular clinical interest. As with many bearing surfaces, it is likely that contact asperities exist at the siz...