On the Exceptional Gauged WZW Theories

We consider two different versions of gauged WZW theories with the exceptional groups and gauged with any of theirs null subgroups. By constructing suitable automorphism, we establish the equivalence of these two theories. On the other hand our automorphism, relates the two dual irreducible Riemannian globally symmetric spaces with different characters based on the corresponding exceptional Lie groups.Comment: 5 pages, LaTeX fil

Wetting and superhydrophobic properties of PECVD grown hydrocarbon and fluorinated-hydrocarbon coatings

Wetting characteristics of micro-nanorough substrates of aluminum and smooth silicon substrates have been studied and compared by depositing hydrocarbon and fluorinated-hydrocarbon coatings via plasma enhanced chemical vapor deposition (PECVD) technique using a mixture of Ar, CH4 and C2F6 gases. The water contact angles on the hydrocarbon and fluorinated-hydrocarbon coatings deposited on silicon substrates were found to be 72° and 105°, respectively. However, the micro-nanorough aluminum substrates demonstrated superhydrophobic properties upon coatings with fluorinated-hydrocarbon providing a water contact angle of ∼165° and contact angle hysteresis below 2° with water drops rolling off from those surfaces while the same substrates showed contact angle of 135° with water drops sticking on those surfaces. The superhydrophobic properties is due to the high fluorine content in the fluorinatedhydrocarbon coatings of ∼36 at.%, as investigated by X-ray photoelectron spectroscopy (XPS), by lowering the surface energy of the micro-nanorough aluminum substrates

Superhydrophobic properties of ultrathin rf-sputtered Teflon films coated etched aluminum surfaces

Superhydrophobicity has been demonstrated on ultrathin rf-sputtered Teflon coated etched aluminum surfaces. The etching of aluminum surfaces has been performed using dilute hydrochloric acid. An optimized etching time of 2.5 min is found to be essential, before Teflon coating, to obtain a highest water contact angle of 164 ± 3° with a lowest contact angle hysteresis of 2.5 ± 1.5°, with the water drops simply rolling off these surfaces with even the slightest inclination of the sample. The presence of − CF3 radicals along with − CF2 radicals in the ultrathin rf-sputtered Teflon films, as investigated by X-ray photoelectron spectroscopy (XPS), contributes to the lowering of the surface energy on the aluminum surfaces. The presence of patterned microstructure as revealed by field emission scanning electron microscope (FESEM) together with the low surface energy ultrathin rf-sputtered Teflon films renders the aluminum surfaces highly superhydrophobic

Polymer masks fabrication by micropatterning surfaces of composite polymer coatings

Micropatterning of surfaces has been demonstrated using composite polymer coatings of PS and PMMA of equal molecular weights in different volume proportions with varying surface topographies on silicon surfaces. The creation of PMMA masks with various surface morphological features has also been demonstrated by removal of PS from the composite coatings using cyclohexane. Atomic force microscopy (AFM) investigations revealed that the surface pattern and the dimensions of these masks significantly changed with the change in the volume proportions of each homopolymer. The composite coatings of 20/80 vol% PS/PMMA, 50/50 vol% PS/PMMA, and 80/20 vol% PS/PMMA resulted in PMMA masks with holes (depth ∼300 nm), wrinkles (height ∼350nm) and pillars (height ∼600 nm), respectively. Surface compositional analysis carried out using FTIR and XPS investigations confirmed the presence of polymer coatings of PS, PMMA and PS/PMMA. XPS investigations also confirmed the successful removal of PS from the PMMA mask by showing the presence of the silicon substrate on those masks where PS was previously present. The water contact angle of the composite polymer masks ranged from 70 to 90° which increased with the increase of PS vol% in the composite. The wetting behavior of certain PMMA masks showed hydrophobicity with water contact angle values above 90°

Optical realization of optimal unambiguous discrimination for pure and mixed quantum states

Quantum mechanics forbids deterministic discrimination among non-orthogonal states. Nonetheless, the capability to distinguish nonorthogonal states unambiguously is an important primitive in quantum information processing. In this work, we experimentally implement generalized measurements in an optical system and demonstrate the first optimal unambiguous discrimination between three nonorthogonal states, with a success rate of 55%, to be compared with the 25% maximum achievable using projective measurements. Furthermore we present the first realization of unambiguous discrimination between a pure state and a nonorthogonal mixed state.Comment: Some minor revision

Impact of foreign aid and foreign direct investment on economic growth: evidence from Sub-Saharan African countries

The purpose of this study is to examine the impact of foreign aid and FDI on economic growth of Sub-Saharan African countries. The generalized method of moments is applied on 41 countries covering the period of 1998 to 2010. The results suggest that while foreign aid has negative effect on growth, the impact of FDI is positive but statistically insignificant. Furthermore, we found evidence that foreign aid from different bilateral donors may have different effects on economic growth

Distributed System Contract Monitoring

The use of behavioural contracts, to specify, regulate and verify systems, is particularly relevant to runtime monitoring of distributed systems. System distribution poses major challenges to contract monitoring, from monitoring-induced information leaks to computation load balancing, communication overheads and fault-tolerance. We present mDPi, a location-aware process calculus, for reasoning about monitoring of distributed systems. We define a family of Labelled Transition Systems for this calculus, which allow formal reasoning about different monitoring strategies at different levels of abstractions. We also illustrate the expressivity of the calculus by showing how contracts in a simple contract language can be synthesised into different mDPi monitors.Comment: In Proceedings FLACOS 2011, arXiv:1109.239

Curvature in Noncommutative Geometry

Our understanding of the notion of curvature in a noncommutative setting has progressed substantially in the past ten years. This new episode in noncommutative geometry started when a Gauss-Bonnet theorem was proved by Connes and Tretkoff for a curved noncommutative two torus. Ideas from spectral geometry and heat kernel asymptotic expansions suggest a general way of defining local curvature invariants for noncommutative Riemannian type spaces where the metric structure is encoded by a Dirac type operator. To carry explicit computations however one needs quite intriguing new ideas. We give an account of the most recent developments on the notion of curvature in noncommutative geometry in this paper.Comment: 76 pages, 8 figures, final version, one section on open problems added, and references expanded. Appears in "Advances in Noncommutative Geometry - on the occasion of Alain Connes' 70th birthday