We show theoretically that flexoelectricity stabilizes blue phases in chiral liquid crystals. Induced internal polarization reduces the elastic energy cost of splay and bend deformations surrounding singular lines in the director field. The energy of regions of double twist is unchanged. This in turn reduces the free energy of the blue phase with respect to that of the chiral nematic phase, lea...

We show that patterned surfaces can promote bistable configurations of nematics for reasons other than the symmetry of the surface. Numerical and analytical calculations reveal that a nematic liquid crystal in contact with a striped surface is subject to the competing aligning influences of elastic anisotropy, differing energy cost of various types of deformation, and flexoelectricity, curvatur...

Availability is one of the most frequently specified quality attributes for computerized systems and the computation of availability requires knowledge about the reliability of the system. Although much research has been devoted to software system reliability, much work remains to be done in identifying ways to predict reliability of assemblies of components. We are designing an experiment for ...

We demonstrate that the frozen-ion contribution to the flexoelectric coefficient is given solely in terms of the sum of third moments of the charge-density distortions induced by atomic displacements, even for ferroelectric or piezoelectric materials. We introduce several practical supercell-based methods for calculating these coefficients from first principles, and demonstrate them by computin...

2014 Using the direct flexoelectric effect in an hybrid (homeotropic-planar) nematic cell, we have measured the bulk flexoelectric coefficient e* for two cyanobiphenyl compounds, 8CB and 8OCB. For 8CB, the flexo coefficient is comparable in sign and magnitude with that of MBBA, i.e. e* ~ + 10-4 cgs. 8OCB presents an anomalously large and negative e* ~ 5 x 10-4 cgs. The small influence of the cy...

This article presents a simplified model for studying the main parameters for magnetically plucking piezoelectric beams in energy harvesting devices. The advantage of magnetic plucking is that there is no impact on the brittle piezo material. However, achieving a good release of the piezo beam is more difficult than with fingers or plectra. The influence of different magnet arrangements, the ga...

Typical holding force of piezo motors is defined by friction force, required to make motor move. However, increase of friction force is not inconsequent for motor performances in terms of speed, max motion force and lifetime (tribology). In this paper, a new motor, offering high resolution positioning and holding position when unpowered, is presented. Based on a Stepping Piezo Actuator [1] at i...