16,515 research outputs found
A weakly universal cellular automaton in the pentagrid with five states
In this paper, we construct a cellular automaton on the pentagrid which is
planar, weakly universal and which have five states only. This result much
improves the best result which was with nine statesComment: 23 pages, 21 figure
Coil planet centrifugation as a means for small particle separation
The coil planet centrifuge uses a centrifugal force field to provide separation of particles based on differences in sedimentation rates by flow through a rotating coiled tube. Three main separations are considered: (1) single phase fresh sheep and human erythrocytes, (2) single phase fixed heep and human erythrocytes, and (3) electrophoretically enhanced single phase fresh sheep and human erythrocytes
A simple beam model for the shear failure of interfaces
We propose a novel model for the shear failure of a glued interface between
two solid blocks. We model the interface as an array of elastic beams which
experience stretching and bending under shear load and break if the two
deformation modes exceed randomly distributed breaking thresholds. The two
breaking modes can be independent or combined in the form of a von Mises type
breaking criterion. Assuming global load sharing following the beam breaking,
we obtain analytically the macroscopic constitutive behavior of the system and
describe the microscopic process of the progressive failure of the interface.
We work out an efficient simulation technique which allows for the study of
large systems. The limiting case of very localized interaction of surface
elements is explored by computer simulations.Comment: 11 pages, 13 figure
Sedimentation of Oblate Ellipsoids at low and Moderate Reynolds numbers
In many applications to biophysics and environmental engineering,
sedimentation of non-spherical particles for example: ellipsoids, is an
important problem. In our work, we simulate the dynamics of oblate ellipsoids
under gravity. We study the settling velocity and the average orientation of
the ellipsoids as a function of volume fraction. We see that the settling
velocity shows a local maximum at the intermmediate densities unlike the
spheres. The average orientation of the ellipsoids also shows a similar local
maximum and we observe that this local maximum disappears as the Reynolds
number is increased. Also, at small volume fractions, we observe that the
oblate ellipsoids exhibit an orientational clustering effect in alignment with
gravity accompanied by strong density fluctuations. The vertical and horizontal
fluctuations of the oblate ellipsoids are small compared to that of the
spheres
Generalized Methodology for Array Processor Design of Real-time Systems
Many techniques and design tools have been developed for mapping algorithms to array processors. Linear mapping is usually used for regular algorithms. Large and complex problems are not regular by nature and regularization may cause a computational overhead which prevents the ability to meet real-time deadlines. In this paper, a systematic design methodology for mapping partially-regular as well as regular Dependence Graphs is presented. In this approach the set of all optimal solutions is generated under the given constraints. Due to nature of the problem and the tight timing constraints of real-time systems the set of alternative solutions is limited. An image processing example is discusse
Calculation of the incremental stress-strain relation of a polygonal packing
The constitutive relation of the quasi-static deformation on two dimensional
packed samples of polygons is calculated using molecular dynamic simulations.
The stress values at which the system remains stable are bounded by a failure
surface, that shows a power law dependence on the pressure. Below the failure
surface, non linear elasticity and plastic deformation are obtained, which are
evaluated in the framework of the incremental linear theory. The results shows
that the stiffness tensor can be directly related to the micro-contact
rearrangements. The plasticity obeys a non-associated flow rule, with a plastic
limit surface that does not agree with the failure surface.Comment: 11 pages, 20 figur
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