162 research outputs found
Method for Particle Size Control During the Drying and Granulation in Fluidized Bed
The fluidized bed process presented in this paper is suitable for recovery of solids from
solutions in the form of granules. The solution is sprayed into the bed and as solvent
evaporates, solid material is deposited on the surface of fluidizing particles. During this
process, particle growth takes place by surface layering and/or agglomeration. A special
grinder is used in the fluidized bed to control particle growth by causing selective
disintegration of large particles. For steady state operation, the most important task is to
determine the existing particle size distribution in the fluidized bed. A special method
was developed to measure torque and stress fluctuations* in the bed of particles. Using a
correlation between torque and stress fluctuations and particle size, this method and
device can be used for direct control of the rotation speed of the grinder to produce
granules of given size in the fluidized bed. Results of torque and stress measurements
and their correlation to particle size are presented
Particle Size Control by Torque Measurements in Fluidized Beds during Drying and Granulation from Solutions
The fluidized bed process presented in this paper is suitable to recover solids from solution in
form of granules. Solution is sprayed into the bed and, as the solvent evaporates, solid
material is deposited on the surface of fluidizing particles. During this process, particle
growth takes place by surface layering and/or agglomeration. A special grinder is used in the
fluidized bed to control particle growth by causing selective disintegration of large particles.
For steady state operation, the most important task is to determine the existing particle size
distribution in the fluidized bed. A special method was developed to measure torque and
stress fluctuations in the bed of particles. Using a correlation between torque and particle size,
this method and device can be used for direct control of the rotation speed of the grinder to
produce granules of given size in the fluidized bed. In this paper, the results of torque
measurements and their correlation with particle size are presented
Torque Measurements and DEM Simulations in a Couette-type Device with Application to Particle Size Measurements
A continuously operating modified Cuette-type shearing device has been developed for
in-situ measurements to estimate the average particle size during size enlargement
processes in fluidized bed granulator. It was proven by experiments that well-defined
correlation exists between the mean torque and the average particle size being in the
device. DEM simulations revealed interesting aspects of this method
Polychromatic Coloring for Half-Planes
We prove that for every integer , every finite set of points in the plane
can be -colored so that every half-plane that contains at least
points, also contains at least one point from every color class. We also show
that the bound is best possible. This improves the best previously known
lower and upper bounds of and respectively. We also show
that every finite set of half-planes can be colored so that if a point
belongs to a subset of at least of the half-planes then
contains a half-plane from every color class. This improves the best previously
known upper bound of . Another corollary of our first result is a new
proof of the existence of small size \eps-nets for points in the plane with
respect to half-planes.Comment: 11 pages, 5 figure
Deterministic Random Walks on the Integers
Jim Propp's P-machine, also known as the "rotor router model" is a simple deterministic process that simulates a random walk on a graph. Instead of distributing chips to randomly chosen neighbors, it serves the neighbors in a fixed order. We investigate how well this process simulates a random walk. For the graph being the infinite path, we show that, independent of the starting configuration, at each time and on each vertex, the number of chips on this vertex deviates from the expected number of chips in the random walk model by at most a constant c_1, which is approximately 2.29. For intervals of length L, this improves to a difference of O(log L), for the L_2 average of a contiguous set of intervals even to O(sqrt{log L}). All these bounds are tight
Concentrated Differential Privacy: Simplifications, Extensions, and Lower Bounds
"Concentrated differential privacy" was recently introduced by Dwork and
Rothblum as a relaxation of differential privacy, which permits sharper
analyses of many privacy-preserving computations. We present an alternative
formulation of the concept of concentrated differential privacy in terms of the
Renyi divergence between the distributions obtained by running an algorithm on
neighboring inputs. With this reformulation in hand, we prove sharper
quantitative results, establish lower bounds, and raise a few new questions. We
also unify this approach with approximate differential privacy by giving an
appropriate definition of "approximate concentrated differential privacy.
Particle Size Control by Torque and Stress Measurement in Fluidized Bed Drying and Granulation from Solutions
The fluidized bed process presented in this paper is suitable for recovery of solids from
solutions in the form of granules. The solution is sprayed into the bed and as solvent
evaporates, solid material is deposited on the surface of fluidizing particles. During this
process, particle growth takes place by surface layering and/or agglomeration. A special
grinder is used in the fluidized bed to control particle growth by causing selective
disintegration of large particles. For steady state operation, the most important task is to
determine the existing particle size distribution in the fluidized bed. A special method was
developed to measure torque and stress fluctuations* in the bed of particles. Using a
correlation between torque and stress fluctuations and particle size, this method and device
can be used for direct control of the rotation speed of the grinder to produce granules of
given size in the fluidized bed. Results of torque and stress measurements and their
correlation to particle size are presented
Conflict-free colorings of graphs and hypergraphs Probability and Computing
A colouring of the vertices of a hypergraph H is called conflict-free if each hyperedge E of H contains a vertex of 'unique' colour that does not get repeated in E. The smallest number of colours required for such a colouring is called the conflict-free chromatic number of H, and is denoted by chi(CF)(H). This parameter wits first introduced by Even, Lotker, Ron and Smorodinsky (FOCS 2002) in a geometric setting, in connection with frequency assignment problems for cellular networks. Here we analyse this notion for general hypergraphs. It is shown that chi(CF)(H) = 3. Using Lovasz's Local Lemma, the same result holds for hypergraphs in which the size of every edge is at least 2t - 1 and every edge intersects at most tit others. We give efficient polynomial-time algorithms to obtain such colourings
Partitioning multi-dimensional sets in a small number of ``uniform'' parts
In this paper we prove that every finite subset of ZxZ
can be partitioned into a small number of subsets so that,
in each part all vertical sections have aproximately the same size and
all horyzontal sections have aproximately the same size. The generalization
of this statement is used to give a combinatorial interpretation to
every information inequality
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