Algorithm for numerical integration of the rigid-body equations of motion

A new algorithm for numerical integration of the rigid-body equations of motion is proposed. The algorithm uses the leapfrog scheme and the quantities involved are angular velocities and orientational variables which can be expressed in terms of either principal axes or quaternions. Due to specific features of the algorithm, orthonormality and unit norms of the orientational variables are integrals of motion, despite an approximate character of the produced trajectories. It is shown that the method presented appears to be the most efficient among all known algorithms of such a kind.Comment: 4 pages, 1 figur

A motif-based approach to network epidemics

Networks have become an indispensable tool in modelling infectious diseases, with the structure of epidemiologically relevant contacts known to affect both the dynamics of the infection process and the efficacy of intervention strategies. One of the key reasons for this is the presence of clustering in contact networks, which is typically analysed in terms of prevalence of triangles in the network. We present a more general approach, based on the prevalence of different four-motifs, in the context of ODE approximations to network dynamics. This is shown to outperform existing models for a range of small world networks

Studies of the adsorption of N2 on the graphite basal plane by computer simulation

A molecular model for the physical adsorption of nitrogen on graphitized carbon black (gcb) has been utilized extensively in computer simulations of this system. After a brief review of the details of the model and of the simulation technique, a number of results produced in the course of these studies are summarized. These include the thermodynamic and structural properties of N2 adsorbed on gcb at 73.6 K and at coverages ranging up to ~2 1 2 monolayers. Changes in molecular orientation relative to the surface are found to have a significant effect on the lateral interaction in a layer; variations in packing density in the first layer are discussed; and the rate of molecular interchange between first and second layers is characterized. Likely directions for future simulation studies of physisorbed films are proposed. © 1987

Studies of the adsorption of N2 on the graphite basal plane by computer simulation

A molecular model for the physical adsorption of nitrogen on graphitized carbon black (gcb) has been utilized extensively in computer simulations of this system. After a brief review of the details of the model and of the simulation technique, a number of results produced in the course of these studies are summarized. These include the thermodynamic and structural properties of N2 adsorbed on gcb at 73.6 K and at coverages ranging up to ~2 1 2 monolayers. Changes in molecular orientation relative to the surface are found to have a significant effect on the lateral interaction in a layer; variations in packing density in the first layer are discussed; and the rate of molecular interchange between first and second layers is characterized. Likely directions for future simulation studies of physisorbed films are proposed. © 1987