Detecting symmetry in scalar fields using augmented extremum graphs

Visualizing symmetric patterns in the data often helps the domain scientists make important observations and gain insights about the underlying experiment. Detecting symmetry in scalar fields is a nascent area of research and existing methods that detect symmetry are either not robust in the presence of noise or computationally costly. We propose a data structure called the augmented extremum graph and use it to design a novel symmetry detection method based on robust estimation of distances. The augmented extremum graph captures both topological and geometric information of the scalar field and enables robust and computationally efficient detection of symmetry. We apply the proposed method to detect symmetries in cryo-electron microscopy datasets and the experiments demonstrate that the algorithm is capable of detecting symmetry even in the presence of significant noise. We describe novel applications that use the detected symmetry to enhance visualization of scalar field data and facilitate their exploration.

Capturability of augmented proportional navigation (APN) guidance with nonlinear engagement dynamics

Proportional Navigation (PN) and its variants are widely used guidance philosophies. However, in the presence of target maneuver, PN guidance law is effective only for a restrictive set of initial geometries. To account for target maneuvers, the concept of Augmented Proportional Navigation (APN) guidance law was introduced and analyzed in a linearized interceptor-target engagement framework presented in literature. However, there is no work in the literature, that addresses the capturability performance of the APN guidance law in a nonlinear engagement framework. This paper presents such an analysis and obtains the conditions for capturability. It also shows that a shorter time of interception is obtained when APN is formulated in the nonlinear framework as proposed in this paper. Simulation results are given to support the theoretical findings.

Solar thermal power system augmented with LHP

The present work reports the study of the bubble formation dynamics in the compensation chamber (CC) of the evaporator in Loop Heat Pipes. A series of experiments were conducted at different heat loads and bubbles in the CC were visualized. Bubbles diameter, frequency and velocity were measured and correlated against heat loads. Temperatures were measured at various locations and heat transfer coefficient was calculated. Performance of the LHP evaporator was evaluated at different heat loads. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

Capturability of Augmented Pure Proportional Navigation Guidance Against Time-Varying Target Maneuvers

This paper proposes a variation of the pure proportional navigation guidance law, called augmented pure proportional navigation, to account for target maneuvers, in a realistic nonlinear engagement geometry, and presents its capturability analysis. These results are in contrast to most work in the literature on augmented proportional navigation laws that consider a linearized geometry imposed upon the true proportional navigation guidance law. Because pure proportional navigation guidance law is closer to a realistic implementation of proportional navigation than true proportional navigation law, and any engagement process is predominantly nonlinear, the results obtained in this paper are more realistic than any available in the literature. Sufficient conditions on speed ratio, navigation gain, and augmentation parameter for capturability, and boundedness of lateral acceleration, against targets executing piecewise continuous maneuvers with time, are obtained. Further, based on a priori knowledge of the maximum maneuver capability of the target, a significant simplification of the guidance law is proposed in this paper. The proposed guidance law is also shown to require a shorter time of interception than standard pure proportional navigation and augmented proportional navigation. To remove chattering in the interceptor maneuver at the end phase of the engagement, a hybrid guidance law using augmented pure proportional navigation and pure proportional navigation is also proposed. Finally, the guaranteed capture zones of standard and augmented pure proportional navigation guidance laws against maneuvering targets are analyzed and compared in the normalized relative velocity space. It is shown that the guaranteed capture zone expands significantly when augmented pure proportional navigation is used instead of pure proportional navigation. Simulation results are given to support the theoretical findings.

Self-assembly of a redox active water soluble Pd6L8 `molecular dice'

A water soluble `molecular dice' was synthesised via coordination driven self-assembly of a Pd(II) ion with a flexible cationic tritopic donor and was fully characterised using NMR, ESI-MS and single crystal X-ray diffraction analysis. The donor-inherited redox active nature of the `molecular dice' was studied using cyclic voltammetry.

Green Nanosilver as Reinforcing Eco-Friendly Additive to Epoxy Coating for Augmented Anticorrosive and Antimicrobial Behavior

Epoxy resin GY250 representing diglycidyl ethers of bisphenol-A (DGEBA) was reinforced with 1, 3 and 5 wt % of surface functionalized silver nanoparticles (F-AgNPs) which were synthesized using Couroupita guianensis leaves extract with a view of augmenting the corrosion control property of the epoxy resin and also imparting antimicrobial activity to epoxy coatings on mild steel. Corrosion resistance of the coatings was evaluated by EIS, potentiodynamic polarization studies and cross scratch tests. AFM, SEM, HRTEM and EDX were utilized to investigate the surface topography, morphology and elemental composition of the coatings on MS specimens. Results showed that the corrosion resistance, hardness and T-g of the DGEBA/F-AgNPs coatings increased at 1 wt % of F-AgNPs. The DGEBA/F-AgNPs coatings also offered manifold antimicrobial protection to the MS surfaces by inhibiting the growth of biofilm forming bacteria like P. aeruginosa, B. subtilis, the most common human pathogen E. coli and the most virulent human pathogenic yeast C. albicans.

The role of the term spread in an augmented Taylor rule: An empirical investigation

Using US data for the period 1967:5-2002:4, this paper empirically investigates the performance of an augmented version of the Taylor rule (ATR) that (i) allows for the presence of switching regimes, (ii) considers the long-short term spread in addition to the typical variables, (iii) uses an alternative monthly indicator of general economic activity suggested by Stock and Watson (1999), and (iv) considers interest rate smoothing. The estimation results show the existence of switching regimes, one characterized by low volatility and the other by high volatility. Moreover, the scale of the responses of the Federal funds rate to movements in the term spread, inflation and the economic activity index depend on the regime. The estimation results also show robust empirical evidence that the ATR has been more stable during the term of office of Chairman Greenspan than in the pre-Greenspan period. However, a closer look at the Greenspan period shows the existence of two alternative regimes and that the response of the Fed funds rate to inflation has not been significant during this period once the term spread is considered.

Augmented Peter Pan: un cuento multilingüe con Realidad Aumentada

[SPA] El objetivo de este Trabajo de Fin de Grado ha sido diseñar un cuento multilingüe que incorpora una innovación tecnológica, la Realidad Aumentada, para favorecer el proceso de enseñanza-aprendizaje lingüístico en la escuela. Para ello, hemos analizado algunos cuentos con Realidad Aumentada que se pueden encontrar en el mercado. Al no encontrar ningún cuento que cumpliese nuestras expectativas, hemos creado un cuento multilingüe con Realidad Aumentada adaptando el cuento clásico “Peter Pan”, que cumple los objetivos de fomentar el aprendizaje de diferentes idiomas y el gusto por la lectura, valorar las lenguas inmigrantes en las aulas y promover el uso de las TIC.