Navegando por Autor "Stauffer, Dietrich"
Agora exibindo 1 - 4 de 4
Resultados por página
Opções de Ordenação
Item Anomalous phase separation dynamics in the presence of surfactants(1996) Bernardes, Américo Tristão; Liverpool, T. B.; Stauffer, DietrichWe study the phase separation of water and oil in a water-oil-surfactant microemulsion, from a totally disordered phase in both two and three dimensions using extensive Monte Carlo simulations of a spin model of microemulsions. The evolution of the characteristic length scale and the structure factor are measured and compared with recent experiments and theoretical work. At relatively high surfactant concentrations and off-critical quenches, we obtain results in agreement with earlier theoretical approaches. For critical quenches at very low surfactant concentrations, we observe the surprising result that it is easier to get to the scaling regime than in the pure binary caseItem Dynamics of interacting polymer chains and solvents.(1996) Pandey, R. B.; Bernardes, Américo Tristão; Foo, G. M.; Stauffer, DietrichConformation and dynamics of charged polymer chains in counter-ion solvent is studied by a Monte Carlo simulation in two and three dimensions. The nodes of the chains are positively charged while the solvent particles possess negative charge. The concentration of the polymer ( p ), and the empty sites ( pe ) is varied along with the temperature. Reptation, kink-jump, and a buckling governed by the interaction energy are considered in moving the chain segments. The variation of the root mean square (rms) displacement of the center of mass, and the relaxation of the radius of gyration of the chains with time are studied as a function of polymer concentration and temperature. The rms displacement of the polymer chains exhibits various power laws in different time regimes which depend on the concentration of the chains. Relaxation of the radius of gyration is enhanced on increasing the temperature; the relaxation time seems to decrease on reducing the chain length and increase on increasing the concentration. The motion of solvent particles show subdiffusive behavior which is sensitive to polymer concentration.Item Monte Carlo simulation of inherited longevity.(1999) Oliveira, Paulo Murilo Castro de; Oliveira, Suzana Maria Moss de; Bernardes, Américo Tristão; Stauffer, DietrichWithin the Penna model of biological ageing, we show that longevity is heritable, for both sexual and asexual reproduction.Item Siblings of centenarians live longer : a computer simulation.(1998) Oliveira, Paulo Murilo Castro de; Oliveira, Suzana Maria Moss de; Bernardes, Américo Tristão; Stauffer, Dietrich