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Abstract: Two discrete-time deterministic epidemic models are analysed numerically in order to determine their properties and evolutions. One of the models is formulated as discrete-time approximation of a corresponding continuous-time model. Restrictive assumptions are made on the parameters of the models, in order to guarantee that the transitions are determined by true probabilities, so that comparisons with stochastic discrete-time previsions can be also provided. The conditions that lead to periodicity in the infectious disease are investigated. It is found that the epidemic oscillates when a small fraction of individuals became not permanently immunised. Smaller the probability that a recovered becomes susceptible, generally larger the period of the oscillations in the infected population. [Copyright &y& Elsevier]

Dripping from steel nozzles with tip of different forms is analysed. It is found that patterns of bifurcation diagrams strongly depend upon the geometrical parameters at the exit. An asymmetrical shape of the outlet induces transversal oscillations on the pending drop. Dynamics widely simplifies for thin walls of the tube and for asymmetrical dripping. [Copyright &y& Elsevier]