Disclination-mediated thermo-optical response in nematic glass sheets

Nematic solids respond strongly to changes in ambient heat or light, significantly differently parallel and perpendicular to the director. This phenomenon is well characterized for uniform director fields, but not for defect textures. We analyze the elastic ground states of a nematic glass in the membrane approximation as a function of temperature for some disclination defects with an eye towards reversibly inducing three-dimensional shapes from flat sheets of material, at the nano-scale all the way to macroscopic objects, including non-developable surfaces. The latter offers a new paradigm to actuation via switchable stretch in thin systems.Comment: Specific results for spiral defects now added. References to Witten, Mahadevan and Ben Amar now added

The Second Language Classroom Modes by Senior English Teacher at XYZ English Course in Surabaya

This study is intended to find out the pedagogic goals, interactional features, and L2 classroom modes appeared in the fourth graders' English classroom taught by senior English teacher. Conducting this study, I apply Walsh's (2006, 2011) SETT (Self-Evaluation of Teacher Talk) framework. The data was collected for two meetings. The findings of this study show that among 18 pedagogic goals, 16 of them appeared. Moreover, all of 14 interactional features and all of four modes appeared in this study.Among the four modes, managerial mode was the most frequent mode (54.54%). In conclusion, the teacher could make the class interactive because she allowed learners to formulate responses for seconds so that learners could contribute more. Moreover, the teacher rarely completed learners' contribution and corrected learners' mistakes directly so that the learners might feel confident to contribute in the activities

Spontaneous Lorentz Violation, Nambu-Goldstone Modes, and Massive Modes

In any theory with spontaneous symmetry breaking, it is important to account for the massless Nambu-Goldstone and massive Higgs modes. In this short review, the fate of these modes is examined for the case of a bumblebee model, in which Lorentz symmetry is spontaneously broken.Comment: 5 pages. Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 201

Frame, metric and geodesic evolution in shape-changing nematic shells.

Non-uniform director fields in flat, responsive, glassy nematic sheets lead to the induction of shells with non-trivial topography on the application of light or heat. Contraction along the director causes metric change, with, in general, the induction of Gaussian curvature, that drives the topography change. We describe the metric change, the evolution of the director field, and the transformation of reference state material curves, e.g. spirals into radii, as curvature develops. The non-isometric deformations associated with heat or light change the geodesics of the surface, intriguingly even in regions where no Gaussian curvature results

Negative Gaussian curvature from induced metric changes.

We revisit the light or heat-induced changes in topography of initially flat sheets of a solid that elongate or contract along patterned in-plane director fields. For radial or azimuthal directors, negative Gaussian curvature is generated-so-called "anticones." We show that azimuthal material displacements are required for the distorted state to be stretch free and bend minimizing. The resultant shapes are smooth and asterlike and can become reentrant in the azimuthal coordinate for large deformations. We show that care is needed when considering elastomers rather than glasses, although the former offer huge deformations.This is the author accepted manuscript. The final version is available from American Physical Society via http://dx.doi.org/10.1103/PhysRevE.92.01040

Quasinormal modes prefer supersymmetry ?

One ambiguity in loop quantum gravity is the appearance of a free parameter which is called Immirzi parameter. Recently Dreyer has argued that this parameter may be fixed by considering the quasinormal mode spectrum of black holes, while at the price of changing the gauge group to SO(3) rather than the original one SU(2). Physically such a replacement is not quite natural or desirable. In this paper we study the relationship between the black hole entropy and the quasi normal mode spectrum in the loop quantization of N=1 supergravity. We find that a single value of the Immirzi parameter agrees with the semiclassical expectations as well. But in this case the lowest supersymmetric representation dominates, fitting well with the result based on statistical consideration. This suggests that, so long as fermions are included in the theory, supersymemtry may be favored for the consistency of the low energy limit of loop quantum gravity.Comment: 3 page