Poster Session and Reception
Tuesday, February 27, 2018 - 5:20pm - 6:30pm
- Adaptive Moving Mesh Method for Phase Field Models of Two-Phase Fluid Flows
Mohamed Sulman (Wright State University)
An efficient adaptive mesh method is developed for solving phase field model of two-phase incompressible fluid flows. The adaptive mesh is computed based on solving a parabolic Monge-Ampe`re equation (PMA). Several numerical experiments are given to demonstrate the performance of the adaptive mesh method in capturing the moving interface between the two fluids.
- Upconversion photoemission studies on Yb3+/Er3+ codoped Sb2O3-WO3-Li2O (SWL) ceramic phosphor for multifunctional applications
Prasenjit Sukul (Indian School of Mines)
Herein, the work reports the synthesis & characterization of a novel luminescent material for multifunctional applications based on upconversion photoemission. The upconversion (UC) emission studies on Yb3+/Er3+ co-doped Sb2O3-WO3-Li2O (SWL) ceramics has been studied upon 980 nm laser excitation. UC emission intensity ratio of green to red bands is found too high to neglect the contribution of the red emission band, which is not observed normally in Yb3+/ Er3+ doped phosphor materials. The variation in upconversion emission intensity is studied with the increase in excitation power as well as temperature of the sample. It has been established that the emission bands centred at 525 and 545 nm are thermally coupled and can act as a temperature sensor in the 300–480 K temperature range. The upconversion emission of the 2H11/2→4I15/2 (525 nm) and 4S3/2→4I15/2 (545 nm) transitions can be employed to the solar cell as it converts a larger amount of NIR radiation into the 525 & 545 nm i.e. visible green emission.
- Transformation optics with applications to invisibility cloaks and other optic devices
Jichun Li (University of Nevada)
In this poster, we will present the basic principle of transformation optics and some applications in optic devices. More specifically, we first present an invisible carpet cloak model and the time-domain finite element method for solving it. We then show how to use transformation optics to obtain modeling equations for electromagnetic concentrator, rotator and splitter. Numerical results are presented to justify their performance.
- Probing Nanoscale Orientation Ordering with Polarized Resonant Soft X-ray Scattering
Chenhui Zhu (Lawrence Berkeley National Laboratory)
An interesting phenomenon in soft matter is that achiral molecules can form chiral structures due to spontaneous symmetry breaking. We have demonstrated the power of polarized resonant soft x-ray scattering (R-SoXS) in deciphering novel liquid crystal helical structures, e.g. the helical nanofilament liquid crystal phase (HNF), and the recently discovered twist bend nematic phase (N(sub)TB). The basic working principle is based on the bond orientation sensitivity, enabled by linearly polarized soft x-rays and the tensorial structure factor near the absorption edge of carbon K-edge. We investigate the role of chirality in the formation of HNF, N(sub)TB, and blue phase liquid crystals. Our approach provides key information on the structure and dynamics of novel liquid crystal phases, which are inaccessible by other techniques.
- Field patterns: A new type of wave
Ornella Mattei (The University of Utah)
Field patterns are a new type of wave propagating in one-dimensional linear media with moduli that vary both in space and time. Specifically, the geometry of these space-time materials is commensurate with the slope of the characteristic lines so that a disturbance does not generate a complicate cascade of subsequent disturbances, but rather concentrates on a periodic space-time pattern, that we call field pattern. Field patterns present spectacularly novel features. One of the most interesting ones is the appearance of a wave generated from an instantaneous source, whose amplitude, unlike a conventional wake, does not tend to zero away from the wave front. Furthermore, very interestingly, the band structure associated with these special space-time geometries is infinitely degenerate: associated with each point on the dispersion diagram is an infinite space of Bloch functions, a basis for which are generalized functions each concentrated on a field pattern.
- The QTZ-QZD Surface: A Family of Chiral Triply Periodic Minimal Surfaces
Elisabetta Matsumoto (Georgia Institute of Technology)
Cubic phases, which often feature triply periodic minimal surfaces and their constant mean curvature variants, frequently self-assemble in diblock copolymers, lyotropic liquid crystals, micellar solutions and lipid membranes. These striking, intricate structures are responsible for much of the vivid structural coloration seen in butterfly wing scales and in the shells of beetles. Although some beetles use chiral cholesteric liquid crystals to create circular dichroism, most cubic phases area achiral and do not yield such optical responses. Here, we describe the QTZ-QZD family of surfaces with tunable chiral pitch. We devise an algorithm to generate the QTZ-QZD surface as a function of the chiral pitch, within a suitable range.