1,080 research outputs found
Analytical study of catalytic reactors for hydrazine decomposition. One and two dimensional steady-state programs, computer programs manual
Programs manual for one-dimensional and two- dimensional steady state models of catalyzed hydrazine decomposition reaction chamber
Study of hydrazine reactor vacuum start characteristics Quarterly progress report, 1 May - 31 Jul. 1969
Liquid hydrazine penetration into catalyst particles upon immersion and decomposition of hydrazine ga
Bond percolation on isoradial graphs: criticality and universality
In an investigation of percolation on isoradial graphs, we prove the
criticality of canonical bond percolation on isoradial embeddings of planar
graphs, thus extending celebrated earlier results for homogeneous and
inhomogeneous square, triangular, and other lattices. This is achieved via the
star-triangle transformation, by transporting the box-crossing property across
the family of isoradial graphs. As a consequence, we obtain the universality of
these models at the critical point, in the sense that the one-arm and
2j-alternating-arm critical exponents (and therefore also the connectivity and
volume exponents) are constant across the family of such percolation processes.
The isoradial graphs in question are those that satisfy certain weak conditions
on their embedding and on their track system. This class of graphs includes,
for example, isoradial embeddings of periodic graphs, and graphs derived from
rhombic Penrose tilings.Comment: In v2: extended title, and small changes in the tex
Restoring site percolation on a damaged square lattice
We study how to restore site percolation on a damaged square lattice with
nearest neighbor (N) interactions. Two strategies are suggested for a
density of destroyed sites by a random attack at . In the first one, a
density of new sites are created with longer range interactions, either
next nearest neighbor (N) or next next nearest neighbor (N). In the
second one, new longer range interactions N or N are created for a
fraction of the remaining sites in addition to their N
interactions. In both cases, the values of and are tuned in order to
restore site percolation which then occurs at new percolation thresholds,
respectively , , and . Using Monte Carlo
simulations the values of the pairs , and , are calculated for the whole range . Our schemes are applicable to all regular lattices.Comment: 5 pages, revtex
Bridge Decomposition of Restriction Measures
Motivated by Kesten's bridge decomposition for two-dimensional self-avoiding
walks in the upper half plane, we show that the conjectured scaling limit of
the half-plane SAW, the SLE(8/3) process, also has an appropriately defined
bridge decomposition. This continuum decomposition turns out to entirely be a
consequence of the restriction property of SLE(8/3), and as a result can be
generalized to the wider class of restriction measures. Specifically we show
that the restriction hulls with index less than one can be decomposed into a
Poisson Point Process of irreducible bridges in a way that is similar to Ito's
excursion decomposition of a Brownian motion according to its zeros.Comment: 24 pages, 2 figures. Final version incorporates minor revisions
suggested by the referee, to appear in Jour. Stat. Phy
Hopping Conduction and Bacteria: Transport in Disordered Reaction-Diffusion Systems
We report some basic results regarding transport in disordered
reaction-diffusion systems with birth (A->2A), death (A->0), and binary
competition (2A->A) processes. We consider a model in which the growth process
is only allowed to take place in certain areas--"oases"--while the rest of
space--the "desert"--is hostile to growth. In the limit of low oasis density,
transport is mediated through rare "hopping" events, necessitating the
inclusion of discreteness effects in the model. By first considering transport
between two oases, we are able to derive an approximate expression for the
average time taken for a population to traverse a disordered medium.Comment: 4 pages, 2 figure
Pretransitional phenomena in dilute crystals with first-order phase transition
Pretransitional phenomena at first-order phase transition in crystals diluted
by 'neutral' impurities (analogue of nonmagnetic atoms in dilute magnets) are
considered. It is shown that field dependence of order parameter becomes
nonanalytical in the stability region of the ordered phase, while smeared jumps
of thermodynamic parameters and anomalous (non-exponential) relaxation appear
near transition temperature of pure crystal.Comment: 4 page
Equality of bond percolation critical exponents for pairs of dual lattices
For a certain class of two-dimensional lattices, lattice-dual pairs are shown
to have the same bond percolation critical exponents. A computational proof is
given for the martini lattice and its dual to illustrate the method. The result
is generalized to a class of lattices that allows the equality of bond
percolation critical exponents for lattice-dual pairs to be concluded without
performing the computations. The proof uses the substitution method, which
involves stochastic ordering of probability measures on partially ordered sets.
As a consequence, there is an infinite collection of infinite sets of
two-dimensional lattices, such that all lattices in a set have the same
critical exponents.Comment: 10 pages, 7 figure
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