Packed beds may be considered as microscopically disordered porous materials for which network models can be employed to represent the topology and morphology of the pore space. In this study, a network model is developed to describe the transport of mass of a neutral tracer when it is injected...

The progressive deactivation of catalytic surfaces, either by parallel or serial fouling, is a key problem in heterogeneous catalysis. A mathematical model of the deactivation of a catalytic reactor is presented. It is shown that this dynamical model can be turned into the study of the...

We propose a growth mechanism for branched polymers where self-organization leads the system to criticality. By incorporating a dynamical rule which simply regulates the flux of monomers available for aggregation, the system is spontaneously driven to the critical branching probability which...

The proportional elections held in Brazil in 1998 and 2002 display identical statistical signatures. In particular, the distribution of votes among candidates includes a power-law regime. We suggest that the rationale behind this robust scaling invariance is a multiplicative process in which the...

We investigate the conductivity variation with density of compacted vapour-grown carbon fibre (VGCF). The results indicate a typical transition between a non-linear domain at low compaction conditions and a regime where the conductivity increases roughly linearly with density when the sample is...

The concept of wavelet cross-correlation is used to provide a new approach to identify similar patterns in related data sets, which largely improves the confidence of the results. The method amounts to decompose the data sets in the wavelet space so that correlations between wavelet coefficients...

The Fourier analysis has been applied to observational sea surface temperature (SST) data from the Southern Pacific. The spectral response of the daily temperature fluctuations indicates that the so-called El Niño Southern Oscillation (ENSO) belongs to the class of dynamical phenomena which are...

We study the oil displacement and production behavior in an isothermal thin layered reservoir model subjected to water flooding. We use the CMG’s (Computer Modelling Group) numerical simulators to solve mass balance equations. The influences of the viscosity ratio (m≡μoil/μwater) and the...

We study a decomposition process where all nodes with a targeted degree are removed from the network. Each removal step results in changes in the degrees of the remaining nodes, and other nodes may attain the targeted degree. The processes continue iteratively until no more nodes with the...

This paper presents seven results on irregular systems that are both new and can be described simply. The first three results are related to dynamical and static properties of gradient percolation. Firstly, it is shown that the transient regimes which lead to self-organized gradient percolation...