36 research outputs found
Long wavelength structural anomalies in jammed systems
The structural properties of static, jammed packings of monodisperse spheres
in the vicinity of the jamming transition are investigated using large-scale
computer simulations. At small wavenumber , we argue that the anomalous
behavior in the static structure factor, , is consequential of an
excess of low-frequency, collective excitations seen in the vibrational
spectrum. This anomalous feature becomes more pronounced closest to the jamming
transition, such that at the transition point. We introduce an
appropriate dispersion relation that accounts for these phenomena that leads us
to relate these structural features to characteristic length scales associated
with the low-frequency vibrational modes of these systems. When the particles
are frictional, this anomalous behavior is suppressed providing yet more
evidence that jamming transitions of frictional spheres lie at lower packing
fractions that that for frictionless spheres. These results suggest that the
mechanical properties of jammed and glassy media may therefore be inferred from
measurements of both the static and dynamical structure factors.Comment: 8 pages, 6 figure captions. Completely revised version to appear in
Phys. Rev.
A polarizable ion model for the structure of molten AgI
The results are reported of the molecular dynamics simulations of the
coherent static structure factor of molten AgI at 923 K using a polarizable ion
model. This model is based on a rigid ion potential, to which the many body
interactions due to the anions induced polarization are added. The calculated
structure factor is in better agreement with recent neutron diffraction data
than that obtained by using simple rigid ion pair potentials. The
Voronoi-Delaunay method has been applied to study the relationship between
voids in the spatial distribution of cations and the prepeak of the structure
factor.Comment: 12 pages, 4 figure
INDISIM-YEAST, an individual-based model to study yeast
INDISIM-YEAST, an individual-based simulator, models the evolution of a yeast population by setting
up rules of behaviour for each individual cell according to their own biological rules and characteristics. It
takes into account the uptake, metabolism, budding reproduction and viability of the yeast cells, over a
period of time in the bulk of a liquid medium, occupying a three dimensional closed spatial grid with two
kinds of particles (glucose and ethanol). Each microorganism is characterized by its biomass, genealogical
age, states in the budding cellular reproduction cycle and position in the space among others. Simulations
are carried out for population properties (global properties), as well as for those properties that pertain to
individual yeast cells (microscopic properties). The results of the simulations are in good qualitative
agreement with established experimental trends.Peer Reviewe
Exploring lag phase and growth initiation of a yeast culture by means of an Individual-based Model
Postprint (published version
Effect of the inoculum characteristics on the first stages of a growing yeast population in beer fermentations by means of an individual-based Model
Postprint (published version
The structure of molten AgCl revisited
We have studied the total structure of molten AgCl at 1073 K by means of two polarizable ion models via molecular dynamics simulations. The model potentials consisted of either the Vashishta–Rahman (VR) or the Born–Mayer rigidion potentials to which the anion-induced polarization contribution is added. Both model potentials reproduce well the main features of the structure of molten AgCl with that using the VR model potential giving marginally better results
The structure of molten AgCl revisited
We have studied the total structure of molten AgCl at 1073 K by means of two polarizable ion models via molecular dynamics simulations. The model potentials consisted of either the Vashishta–Rahman (VR) or the Born–Mayer rigidion potentials to which the anion-induced polarization contribution is added. Both model potentials reproduce well the main features of the structure of molten AgCl with that using the VR model potential giving marginally better results.Postprint (published version