The purpose of this study was to analyze the type and frequency of defects in nickel-titanium rotary endodontic files after routine clinical use, and to draw conclusions regarding the reasons for failure. All of the files (total: 378, Quantec Series 2000) discarded after normal use from a specialist endodontic practice over 6 months were analyzed. Almost 50% of the files showed some visible def...

This paper is concerned with the development of a piezoelectric d15 shear-induced torsion actuator made of a lead-free piezoceramic material exhibiting giant piezoelectric shear stress coefficient (e15) and piezoelectric transverse shear actuation force comparable to that of lead-based shear-mode piezoceramics. The Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO3 (NBT-BT-Mn) composition exhibited ex...

A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor's vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density....

A novel method that uses a small mechanical lever has been developed to directly calibrate the lateral sensitivity of the optical lever in the atomic force microscope (AFM). The mechanical lever can convert the translation into a nanoscale rotation angle with a flexible hinge that provides an accurate conversion between the photodiode voltage output and torsional angle of a cantilever. During t...

It is proposed that the randomly diluted elastic network of Hooke's-law central-force springs in two dimensions may have a hitherto unrecognized splay-rigid phase in which the bulk and shear moduli vanish but the Frank elastic constant, K, is nonzero. Exponents for the associated splay-rigidity percolation and torsional resistance are estimated by series-expansion techniques. These exponents ar...

prior to the design and construction of any fruit harvesting machine it is essential to know the physical and mechanical properties of the trees and of its fruits. an example could be cited as the force needed to overcome. the strength with which the fruit is attached to the stem, in trunk shaker harvesting. in this research the acting forces on the fruit during harvest, including tensile stren...

The combination of ultrasound with atomic force microscopy (AFM) opens the high lateral resolution of scanning probe techniques to ultrasonics. Atomic force acoustic microscopy (AFAM) and lateral atomic force acoustic microscopy are techniques which use the vibration modes of AFM cantilevers. In the AFAM-mode the cantilever is vibrating in one of its flexural resonances while the sensor tip is ...

Carbon nanotubes can be distinctly metallic or semiconducting depending on their diameter and chirality. Here we show that continuously varying the chirality by mechanical torsion can induce conductance oscillations, which can be attributed to metal –semiconductor periodic transitions. The phenomenon is observed in multiwalled carbon nanotubes, where both the torque and the current are shown to...

Although the Sun's torsional oscillation is believed to be driven by the Lorentz force associated with the sunspot cycle, this oscillation begins 2-3 yr before the sunspot cycle. We provide a theoretical explanation of this with the help of a solar dynamo model having a meridional circulation penetrating slightly below the bottom of the convection zone, because only in such dynamo models does t...

for a Brownian oscillator, where x(t) specifies the position of the particle or oscillator at time t, m is the mass, ( x is the viscous drag experienced by the particle, lVo is the oscillator frequency, and F(t) is the white-noise driving force. We also consider the rotational analogs of these two models, namely, a free single-axis rotator and a torsional oscillator. The corresponding Langevin ...