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Saint Ives, United Kingdom

This research work describes the modelling of two novel 3-D chaotic systems, the first with a hyperbolic sinusoidal nonlinearity and two quadratic nonlinearities (denoted as system (A)) and the second with a hyperbolic cosinusoidal nonlinearity and two quadratic nonlinearities (denoted as system (B)). In this work, a detailed qualitative analysis of the novel chaotic systems (A) and (B) has been presented, and the Lyapunov exponents and Kaplan-Yorke dimension of these chaotic systems have been obtained. It is found that the maximal Lyapunov exponent (MLE) for the novel chaotic systems (A) and (B) has a large value, viz. for the system (A) and for the system (B). Thus, both the novel chaotic systems (A) and (B) display strong chaotic behaviour. This research work also discusses the problem of finding adaptive controllers for the global chaos synchronization of identical chaotic systems (A), identical chaotic systems (B) and nonidentical chaotic systems (A) and (B) with unknown system parameters. The adaptive controllers for achieving global chaos synchronization of the novel chaotic systems (A) and (B) have been derived using adaptive control theory and Lyapunov stability theory. MATLAB simulations have been shown to illustrate the novel chaotic systems (A) and (B), and also the adaptive synchronization results derived for the novel chaotic systems (A) and (B). ©2013 Kavala Institute of Technology. Source

In this work, a model of computation of temperature field in a half-infinite body caused by heat source with changeable direction of motion was presented. Analytical temperature field was approximated by straight segments for volumetric heat source with a trajectory considering temperature changes caused by next transitions (increase in temperature connected to action of the heat source and self-cooling of areas heated-up earlier). In that instance computations were carried out for cuboidal elements made of S235 steel for various heat trajectories. The results were presented as temporary and maximum temperature distribution in elements' surface and in longitudinal sections. © 2010 Elsevier Ltd. All rights reserved. Source

Selvam S.,42 Technology
Journal of Photochemistry and Photobiology B: Biology

Carvedilol (CVL), a β-adrenergic receptor, is insoluble under physiological conditions and hence its oral administration is difficult. Bile salts are widely used as drug delivery media for many hydrophobic drugs. CVL has a strong intrinsic fluorescence with a carbazole moiety. When excited at 320 nm, it exhibits dual emission at 347 and 357 nm. As the concentration of bile salt is increased there is an overall increase in the fluorescence intensity and also the ratio of the intensities at 347 and 357 nm (I1/I 2) increases. This indicates that the CVL molecule can sense the non-polar nature of bile salts with increasing concentrations. It is showed that the new parameter (I1/I2) can be used as an indicative tool in determining the polarity of the medium. The increase in fluorescence anisotropy and fluorescence lifetimes is observed, indicating the micro-heterogeneity of the bile salt solutions as experienced by CVL molecules. The possibility of electrostatic interactions between CVL and bile salt micelles is ruled out in view of the results obtained here and their interaction is purely hydrophobic in nature. The results suggest that the CVL molecule associates with the steroidal moiety of bile salts through its carbazole moiety. © 2012 Elsevier B.V. All rights reserved. Source

Spatial confinement in nanoporous media affects the structure, thermodynamics and mobility of molecular soft matter often markedly. This article reviews thermodynamic equilibrium phenomena, such as physisorption, capillary condensation, crystallisation, self-diffusion, and structural phase transitions as well as selected aspects of the emerging field of spatially confined, non-equilibrium physics, i.e. the rheology of liquids, capillarity-driven flow phenomena, and imbibition front broadening in nanoporous materials. The observations in the nanoscale systems are related to the corresponding bulk phenomenologies. The complexity of the confined molecular species is varied from simple building blocks, like noble gas atoms, normal alkanes and alcohols to liquid crystals, polymers, ionic liquids, proteins and water. Mostly, experiments with mesoporous solids of alumina, gold, carbon, silica, and silicon with pore diameters ranging from a few up to 50nm are presented. The observed peculiarities of nanopore-confined condensed matter are also discussed with regard to applications. A particular emphasis is put on texture formation upon crystallisation in nanoporous media, a topic both of high fundamental interest and of increasing nanotechnological importance, e.g. for the synthesis of organic/inorganic hybrid materials by melt infiltration, the usage of nanoporous solids in crystal nucleation or in template-assisted electrochemical deposition of nano structures. © 2015 IOP Publishing Ltd. Source

Winczek J.,42 Technology
International Journal of Heat and Mass Transfer

In this work, a model of temperature field in a half-infinite body during surfacing was presented. Analytical solution was obtained by aggregating temperature increments caused by applying liquid metal and heat radiation of moving electrode. The assumptions were heat source of applied metal in parabolic shape in the cross-section of weld and Gaussian distribution of electric arc heat source. Computations of temperature field were carried out during surfacing of cuboidal steel element. The results were presented as temporary and maximum temperature distribution in element's cross section. The accuracy of solution was verified comparing calculated fusion line to that obtained experimentally. © 2011 Elsevier Ltd. All rights reserved. Source

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