46 research outputs found
Random packing of regular polygons and star polygons on a flat two-dimensional surface
Random packing of unoriented regular polygons and star polygons on a
two-dimensional flat, continuous surface is studied numerically using random
sequential adsorption algorithm. Obtained results are analyzed to determine
saturated random packing ratio as well as its density autocorrelation function.
Additionally, the kinetics of packing growth and available surface function are
measured. In general, stars give lower packing ratios than polygons, but, when
the number of vertexes is large enough, both shapes approach disks and,
therefore, properties of their packing reproduce already known results for
disks.Comment: 5 pages, 8 figure
RSA Study of Dimers
The first theoretical study of a dimer's adsorption process at homogenous
surface is presented. By using the RSA algorithm, we show example monolayers,
discuss estimations of random jamming coverage and measure the surface blocking
function, which could be used for calculating real systems kinetics. We also
found the correlation function for generated coverages and analyzed
orientational ordering inside the adsorbed monolayer. Results were compared
with theoretical and experimental data.
Keywords: adsorption, RSA, monolayer, colloid particlesComment: 13 pages, 13 figure
Domain structure created by irreversible adsorption of dimers
Structure of monolayers built during adsorption process is strongly related
to the properties of adsorbed particles. The most important factor is their
shape. For example, adsorption of elongated molecules on patterned surfaces may
produce certain orientational order inside a covering layer. This study,
however, focuses on random adsorption of dimers on flat, homogeneous surfaces.
It has been observed that despite the lack of global orientational ordering,
adsorbed dimers may form local, orientationally ordered structures [1, 2]. Our
investigations focus on the dependence between domain size distribution and
environmental parameters such as ionic strength, which affects the range of
electrostatic interaction between molecules.Comment: 8 pages, 5 figures, Presented at the XXV Marian Smoluchowski
Symposium on Statistical Physics, Krak\'ow, Poland, September, 201
Random sequential adsorption of trimers and hexamers
Adsorption of trimers and hexamers built of identical spheres was studied
numerically using the Random Sequential Adsorption (RSA) algorithm. Particles
were adsorbed on a two dimensional, flat and homogeneous surface. Numerical
simulations allow to establish the maximal random coverage ratio, RSA kinetics
as well as the Available Surface Function (ASF), which is crucial for
determining kinetics of the adsorption process obtained experimentally.
Additionally, the density autocorrelation function was measured. All the
results were compared with previous results obtained for spheres, dimers and
tetramers.Comment: 11 pages, 6 figure
Competitive adsorption of bimodal latex suspension
Competitive deposition of binary mixture of small and large latex particles is studied using Random Sequential Adsorption (RSA) algorithm. We designated the saturated random coverage ratio dependence on small-to-large particle concentration ratio and on particles size ratio. Moreover, the deposition kinetics of the process was calculated numerically. To check validity of the numerical model, the saturated random coverage ratio for 1:1 binary latex particle mixture was measured experimentally using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM)
Physics of free climbing
Theory of stochastic processes provides theoretical tools which can be
efficiently used to explore properties of noise induced escape kinetics. Since
noise facilitated escape over the potential barrier resembles free climbing,
one can use the first passage time theory in analysis of rock climbing. We
perform the analysis of the mean first passage time in order to answer the
question regarding the optimal, i.e., resulting in the fastest climbing, rope
length. It is demonstrated that there is a discrete set of favorable rope
lengths assuring shortest climbing times, as they correspond to local minima of
mean first passage time. Within the set of favorable rope lengths there is the
optimal rope giving rise to the shortest climbing time. In particular, more
experienced climbers can decrease their climbing time by using longer ropes.Comment: 7 pages, 6 figure
Random Sequential Adsorption on Fractals
Irreversible adsorption of spheres on flat collectors having dimension
is studied. Molecules are adsorbed on Sierpinski's Triangle and Carpet like
fractals (), and on General Cantor Set (). Adsorption process is
modeled numerically using Random Sequential Adsorption (RSA) algorithm. The
paper concentrates on measurement of fundamental properties of coverages, i.e.
maximal random coverage ratio and density autocorrelation function, as well as
RSA kinetics. Obtained results allow to improve phenomenological relation
between maximal random coverage ratio and collector dimension. Moreover,
simulations show that, in general, most of known dimensional properties of
adsorbed monolayers are valid for non-integer dimensions.Comment: 12 pages, 8 figure