49,449 research outputs found
Spontaneous Formation of Stable Capillary Bridges for Firming Compact Colloidal Microstructures in Phase Separating Liquids: A Computational Study
Computer modeling and simulations are performed to investigate capillary
bridges spontaneously formed between closely packed colloidal particles in
phase separating liquids. The simulations reveal a self-stabilization mechanism
that operates through diffusive equilibrium of two-phase liquid morphologies.
Such mechanism renders desired microstructural stability and uniformity to the
capillary bridges that are spontaneously formed during liquid solution phase
separation. This self-stabilization behavior is in contrast to conventional
coarsening processes during phase separation. The volume fraction limit of the
separated liquid phases as well as the adhesion strength and thermodynamic
stability of the capillary bridges are discussed. Capillary bridge formations
in various compact colloid assemblies are considered. The study sheds light on
a promising route to in-situ (in-liquid) firming of fragile colloidal crystals
and other compact colloidal microstructures via capillary bridges
Two Decades of Maude
This paper is a tribute to José Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Computational Performance Evaluation of Two Integer Linear Programming Models for the Minimum Common String Partition Problem
In the minimum common string partition (MCSP) problem two related input
strings are given. "Related" refers to the property that both strings consist
of the same set of letters appearing the same number of times in each of the
two strings. The MCSP seeks a minimum cardinality partitioning of one string
into non-overlapping substrings that is also a valid partitioning for the
second string. This problem has applications in bioinformatics e.g. in
analyzing related DNA or protein sequences. For strings with lengths less than
about 1000 letters, a previously published integer linear programming (ILP)
formulation yields, when solved with a state-of-the-art solver such as CPLEX,
satisfactory results. In this work, we propose a new, alternative ILP model
that is compared to the former one. While a polyhedral study shows the linear
programming relaxations of the two models to be equally strong, a comprehensive
experimental comparison using real-world as well as artificially created
benchmark instances indicates substantial computational advantages of the new
formulation.Comment: arXiv admin note: text overlap with arXiv:1405.5646 This paper
version replaces the one submitted on January 10, 2015, due to detected error
in the calculation of the variables involved in the ILP model
Large Scale Earth's Bow Shock with Northern IMF as simulated by PIC code in parallel with MHD model
In this paper, we propose a 3D kinetic model (Particle-in-Cell PIC ) for the
description of the large scale Earth's bow shock. The proposed version is
stable and does not require huge or extensive computer resources. Because PIC
simulations work with scaled plasma and field parameters, we also propose to
validate our code by comparing its results with the available MHD simulations
under same scaled Solar wind ( SW ) and ( IMF ) conditions. We report new
results from the two models. In both codes the Earth's bow shock position is
found to be ~14.8 RE along the Sun-Earth line, and ~ 29 RE on the dusk side.
Those findings are consistent with past in situ observations. Both simulations
reproduce the theoretical jump conditions at the shock. However, the PIC code
density and temperature distributions are inflated and slightly shifted sunward
when compared to the MHD results. Kinetic electron motions and reflected ions
upstream may cause this sunward shift. Species distributions in the foreshock
region are depicted within the transition of the shock (measured ~2
c/{\omega}pi for {\Theta}Bn =90o and MMS =4.7 ) and in the downstream. The size
of the foot jump in the magnetic field at the shock is measured to be (1.7
c/{\omega}pi ). In the foreshocked region, the thermal velocity is found equal
to 213 km.sec-1 at 15 RE and is equal to 63 km.sec-1at 12 RE (Magnetosheath
region). Despite the large cell size of the current version of the PIC code, it
is powerful to retain macrostructure of planets magnetospheres in very short
time, thus it can be used for a pedagogical test purposes. It is also likely
complementary with MHD to deepen our understanding of the large scale
magnetosphereComment: 26 pages, 8 figures, 1 table , 66 references, JOAA-D-16-00005/201
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