An investigation into the properties of a two dimensional (2D+1) system of self propelled particles (known as boids) in free space is conducted using a Lagrangian Individual-Based Model. A potential, associated with each boid is specified and a Lagrangian is subsequently derived in order to obtain the equations of motion for each particle in the flock. The Morse potential and the Lennard-Jones ...

Z. Naturforsch. 54 a, 559-569 (1999); received June 1, 1999 The pressure in the gaseous, the isotropic liquid and nematic liquid crystalline states, as well as the isotropic-nematic transition temperature are calculated for a model system composed of non-spherical particles. The potential is a generalization of the Lennard-Jones interaction where the attractive part depends on the relative orie...

A new molecular simulation method for the calculation of vapour-liquid equilibria of mixtures is presented. In this method, the independent thermodynamic variables are temperature and liquid composition. In the first step, one isobaric isothermal simulation for the liquid phase is performed, in which the chemical potentials of all components and their derivatives with respect to the pressure, i...

We describe a Continuous Hugoniot Method for the efficient simulation of shock wave fronts. This approach achieves a significantly improved efficiency in the generation of individual steady-state shock front states, and allows for the study of shocks as a function of a continuous shock strength parameter, vp. This is, to our knowledge, the first attempt to map the Hugoniot continuously. We appl...

This paper presents a new method for smoothing haptic interaction with molecular force calculations that uses Lennard-Jones forcefield. The gradient of the forcefield is used unaltered when the distance between two atoms is greater than the sum of their van der Waals radii. However, when they are smaller, a hard-surface wall implemented using a spring model is used to repel two atoms. This elim...

A density functional study of the structure of a layer formed by chain molecules pinned to a solid surface is presented. The chains are modeled as freely joined spheres. Segments and all components interact via LennardJones (12–6) potential. The interactions of fluid molecules with the wall are described by the Lennard-Jones (9–3) potential. We analyze how different parameters of the model affe...

Molecular dynamics studies of Go models of proteins with the 10-12 contact potential and the bond and dihedral angle terms indicate statistical similarities to other Go models, e.g. with the Lennard-Jones contact potentials. The folding times depend on the protein size as power laws with the exponents depending on the native structural classes. There is no dependence of the folding times on the...

For investment decisions the development of market trends is very important. In this contribution we present our results concerning the influence of news on market trends. We processed the stock news delivered by the Wall Street Journal with two methods of text mining – Bayes classification and grammar-driven classification. We found some potentialities of Dow Jones trend prediction and present...

We present a study of the expected properties of the low redshift damped Ly-α absorber population determined from a sample of HI-selected galaxies in the local universe. We use measurements of the number density and HI cross-section of galaxies to show that the total HI cross-section at column densities sufficient to produce damped Ly-α absorption is consistent with no evolution of the absorber...

We consider general nanotubes of atoms in R3 where each atom interacts with all others through a two-body potential. When there are no exterior forces, a particular family of nanotubes is the set of perfect nanotubes at the equilibrium. When exterior forces are applied on the nanotube, we compare the nanotube to nanotubes of the previous family. This quantitative comparison is formulated in our...