253 research outputs found
Reply to: Comment on `Long-range electrostatic interactions between like-charged colloids: steric and confinement effects'
In his Comment (cond-mat/0104060) to [Phys. Rev. E 60, 6530 (1999)], Mateescu
shows that while the effective interactions remain repulsive when the specific
size of the micro-ions is taken into account via a Modified Poisson-Boltzmann
equation, a similar conclusion cannot be reached for the situation of complete
lateral confinement. This point is correct but has already been considered in a
more general study [Phys. Rev. E 62, R1465 (2000), where repulsion is
generically obtained]; moreover, we argue that it illustrates the irrelevancy
of the notion of pair potential in completely confined configurations, as shown
on a simple example
USE OF AN INNOVATIVE METHOD FOR STRUCTURAL ANALYSIS OF THE DISTRIBUTION DEVICE USED IN PNEUMATIC MACHINES FOR WEEDING PLANT SOWING
The topic addressed is a computer-aided design (CAD) method combined with computer-aided engineering (CAE) used in the analysis of choosing the optimal constructive variant of the distribution device used in pneumatic machines for weeding plant sowing. The CAD configurations, realized by the 3D parametric modeling using the SolidWorks program, were subjected to structural analysis (von Mises equivalent stress distribution, relative displacement field distribution and safety factor). Based on the resulting data, the mass/resistance coefficient for the 3 analyzed configurations were determined. The comparison of these indicators led to the choice of the optimal constructive variant, namely the most efficient one
Organized condensation of worm-like chains
We present results relevant to the equilibrium organization of DNA strands of
arbitrary length interacting with a spherical organizing center, suggestive of
DNA-histone complexation in nucleosomes. We obtain a rich phase diagram in
which a wrapping state is transformed into a complex multi-leafed, rosette
structure as the adhesion energy is reduced. The statistical mechanics of the
"melting" of a rosette can be mapped into an exactly soluble one-dimensional
many-body problem.Comment: 15 pages, 2 figures in a pdf fil
CAD-CAE METHOD FOR STRUCTURAL ANALYSIS OF THE WELDED FRAME WITHIN THE COMPONENT OF A SEED DRILL USED FORDIRECTLY SOWING STRAW CEREALS
This paper presents a Computer Assisted Design (CAD) method combined with computer-aided engineering (CAE) used in the analysis of choosing the constructive variant of the welded frame from within the component of a seed drill used fordirectly sowing straw cereals, so that the ratio between the consumption of material for the construction structure per unit of safety coefficient to be minimal and the carrying capacity to be maximal. For this purpose 3D modeling with SolidWorks software has effectively managed three dimensional configurations of the welded frame using Design Table. The three configurations were subjected to structural analysis (the von Mises equivalent of the tension field distribution, the relative displacement of field distribution and the safety coefficient). Based on the resulting data, the mass / resistance ratios for the three configurations analyzed were determined. The comparison of these indicators led to the choice of the optimal constructive variant in the most efficient way. The presented method contributes to reducing the design validation time by eliminating physical performance and testing
Comment on "Long-range electrostatic interactions between like-charged colloids: Steric and confinement effects"
In a recent study [Phys. Rev. E 60, 6530 (1999)], Trizac and Raimbault showed
that the effective pair interaction between like charged colloids immersed in a
cylindrically confined electrolyte remains repulsive even when the size of the
micro-ions or the finite longitudinal extension of the confining cylinder are
taken into account. Contrary to their claim, we argue that the case of finite
longitudinal confinement doesn't always generate repulsive interactions and to
illustrate this point we also provide a simple example.Comment: 3 pages, 1 figure. Accepted for publication in Phys. Rev. E 200
ECO-INNOVATIVE SYSTEM PROVIDED WITH "DEFLECTOR" TO REDUCE POWDER EMISSIONS AT HOEING PLANTS SOWING
This paper presents experimental research carried out by INMA Bucharest for the implementation of measures to reduce particulate matter emissions from seeds treated with plant protection chemicals during sowing crops. The work is justified by stringent national and European requirements to increase the capacity and capability of the R & D system in the agricultural field by promoting and supporting the development of eco-innovative systems to mitigate the risks associated with the use of plant protection products
Conformation of a Polyelectrolyte Complexed to a Like-Charged Colloid
We report results from a molecular dynamics (MD) simulation on the
conformations of a long flexible polyelectrolyte complexed to a charged sphere,
\textit{both negatively charged}, in the presence of neutralizing counterions
in the strong Coulomb coupling regime. The structure of this complex is very
sensitive to the charge density of the polyelectrolyte. For a fully charged
polyelectrolyte the polymer forms a dense two-dimensional "disk", whereas for a
partially charged polyelectrolyte the monomers are spread over the colloidal
surface. A mechanism involving the \textit{overcharging} of the polyelectrolyte
by counterions is proposed to explain the observed conformations.Comment: 4 pages, 4 figures (6 EPS files
Analysis and Verification of Service Interaction Protocols - A Brief Survey
Modeling and analysis of interactions among services is a crucial issue in
Service-Oriented Computing. Composing Web services is a complicated task which
requires techniques and tools to verify that the new system will behave
correctly. In this paper, we first overview some formal models proposed in the
literature to describe services. Second, we give a brief survey of verification
techniques that can be used to analyse services and their interaction. Last, we
focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330
A model of inversion of DNA charge by a positive polymer: fractionization of the polymer charge
Charge inversion of a DNA double helix by an oppositely charged flexible
polyelectrolyte (PE) is considered. We assume that, in the neutral state of the
DNA-PE complex, each of the DNA charges is locally compensated by a PE charge.
When an additional PE molecule is adsorbed by DNA, its charge gets fractionized
into monomer charges of defects (tails and arches) on the background of the
perfectly neutralized DNA. These charges spread all over the DNA eliminating
the self-energy of PE. This fractionization mechanism leads to a substantial
inversion of the DNA charge, a phenomenon which is widely used for gene
delivery.Comment: 4 pages, 2 figures. Improved figures and various corrections to tex
Site-Directed Insertion: Decision Problems, Maximality and Minimality
Site-directed insertion is an overlapping insertion operation that can be
viewed as analogous to the overlap assembly or chop operations that concatenate
strings by overlapping a suffix and a prefix of the argument strings. We
consider decision problems and language equations involving site-directed
insertion. By relying on the tools provided by semantic shuffle on trajectories
we show that one variable equations involving site-directed insertion and
regular constants can be solved. We consider also maximal and minimal variants
of the site-directed insertion operation
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