AIM To evaluate the effect of rotational speed and the angle and radius of curvature of root canals on the fracture of two types of nickel-titanium rotary instruments: K3 and ProTaper. METHODOLOGY A total of 240 root canals of extracted human maxillary and mandibular molars were divided into two groups of 120, according to the angle of the canal curvature (group A: <30 degrees, group B: >30 d...

Internal convective cooling is a method by which components, such as gas turbine blades, are protected from damage caused by elevated temperatures. Heat pipes are structures that transport and dissipate large quantities of pressurized thermal energy. The thermal energy is transported from a heat source to a thermal sink via evaporative cooling. A radially rotating high temperature heat pipe . e...

Micromilling process is used for fabrication and manufacturing of miniaturized components. Very high spindle rotational speeds are required in micromilling to reduce the chip load and to counter the low flexural rigidity of the micro-tool while machining hard materials. Apart from the high rotational speed (>100,000 rpm) which can excite dynamic instability, the dynamic force variation in micro...

A 1arge-scale tumble rather than swirl would exist in cylinders in the case of two valves’ opening in a fourvalve engine. A strong swirl is generated when one valve is closed, yet the flow capacity is less than that of two valves being opened. In order to change it, different lifts of valves (DLV) present are achieved. In the case of using different lifts of two intake valves, both tumble and s...

A new route consisting of simultaneous centrifugal spinning and solution blowing to form polymer nanofibers is reported. The fiber diameter (60-1000 nm) is shown to be a function of polymer concentration, rotational speed, and working pressure of the processing system. The fiber length is dependent on the rotational speed. The process can deliver 6 kg of fiber per hour and therefore offers mass...

This paper proposes a new non‐magnetic motor with a rotor rotated by using the resonance en‐ ergy of a bimorph cantilever beam excited by electrostatic force. The use of flexible material en‐ ables conversion of translational vibration to rotary movement in one direction. Basic character‐ istics of a prototype motor with two bimorph cantilever beams, such as rotational speed, output torque, and...

Abstract: In recent decades, micro air vehicles driven by electric propellers have become a hot topic, and developed quickly. The performance of the vehicles depends on the rotational speed of propellers, thus, improving the accuracy of rotational speed measurement is beneficial to the vehicle’s performance. This paper presents the development of a soft sensor for the rotational speed measureme...