Performance: territórios conquistados e negociações de fronteiras

A performance oscila por sua natureza mesma entre diferentes campos artísticos, tornando difícil toda tentativa de estruturação e de classificação. Essa ausência de limites precisos pode ser recolocada em paralelo à noção de fronteiras estabelecidas entre territórios. A Terra, como material de base, fonte mesma de territórios geográficos e políticos foi utilizada plasticamente em algumas performances artísticas. Baseando-se a partir da análise de várias performances, entre estas as do Festival Internacional da Terra (Venezuela 2007), este artigo propõe interrogar as noções de demarcação entre territórios, tanto terrestres quanto artísticos fundamentados sobre a metáfora da terra

Atomistic Study of Water Confined in Silica.

In this work, we have used a combined of atomistic simulation methods to explore the effects of confinement of water molecules between silica surfaces. Firstly, the mechanical properties of water severe confined (~3A) between two silica alpha-quartz was determined based on first principles calculations within the density functional theory (DFT). Simulated annealing methods were employed due to the complex potential energry surface, and the difficulties to avoid local minima. Our results suggest that much of the stiffness of the material (46%) remains, even after the insertion of a water monolayer in the silica. Secondly, in order to access typical time scales for confined systems, classical molecular dynamics was used to determine the dynamical properties of water confined in silica cylindrical pores, with diameters varying from 10 to 40A. in this case we have varied the passivation of the silica surface, from 13% to 100% of SiOH, and the other terminations being SiOH2 and SiOH3, the distribution of the different terminations was obtained with a Monte Carlo simulation. The simulations indicates a lowering of the diffusion coefficientes as the diameter decreases, due to the structuration of hydrogen bonds of water molecules; we have also obtained the density profiles of the confined water and the interfacial tension.