Search results for "init"

Iterative pairs and multitape automata

1996

In this paper we prove that if every iterative k-tuple of a language L recognized by a k-tape automaton is very degenerate, then L is recognizable. Moreover, we prove that if L is an aperiodic langnage recognized by a deterministic k-tape automaton, then L is recognizable.

Personality, occupational sorting and routine work

2020

Purpose – A prominent labour market feature in recent decades has been the increase in abstract and service jobs, while the demand for routine work has declined. This article examines whether the components of Type A behaviour predict workers’ selection into nonroutine abstract, non-routine service and routine jobs. Design/methodology/approach – Building on the work by Barrick et al. (2013), this article first presents how the theory of purposeful work behaviour can be used to explain how individuals with different levels of Type A components sort into abstract, service and routine jobs. Then, using longitudinal data, it examines whether the components of Type A behaviour predict occupation…

Transformations axiologiques au collège : tournant de siècle

2012

National audience; A la naissance du collège unique semble tout d'abord correspondre la disparition d'un enseignement disciplinaire des valeurs en France. Mais tandis que la nécessité d'enseigner une culture commune conduit à la rédaction d'un socle commun, ce dernier se voit doter en 2006 de deux piliers consacrés aux valeurs. D'une part, les compétences sociales et civiques ravivent et enrichissent des injonctions curriculaires connues depuis plus d'un siècle en rappelant aux collégiens des valeurs collectives, sociales et démocratiques. D'autre part, l'autonomie et l'initiative, qui semblent provenir d'orientations extérieures à la communauté éducative ou scientifique et promeuvent des v…

A PH-functionalized polyphosphazene: a macromolecule with a highly flexible backbone.

2006

Structure and transport properties of amorphous aluminium silicates: computer simulation studies

2005

The structure and transport properties of SiO2-Al2O3 melts containing 13 mol% and 47 mol% Al2O3 are investigated by means of large scale molecular dynamics computer simulations. The interactions between the atoms are modelled by a pair potential which is a modified version of the one proposed by Kramer et al. [J. Am. Chem. Soc. 64, 6435 (1991)]. Fully equilibrated melts in the temperature range 6000 K >= T > 2000 K are considered as well as glass configurations, that were obtained by a rapid quench from the lowest melt temperatures. Each system is simulated at two different densities in order to study the effect of pressure on structural and dynamic properties. We find that the Al ato…

Thermal Expansion in Small Metal Clusters and its Impact on the Electric Polarizability

2000

The thermal expansion coefficients of $\mathrm{Na}_{N}$ clusters with $8 \le N \le 40$ and $\mathrm{Al}_{7}$, $\mathrm{Al}_{13}^-$ and $\mathrm{Al}_{14}^-$ are obtained from {\it ab initio} Born-Oppenheimer LDA molecular dynamics. Thermal expansion of small metal clusters is considerably larger than that in the bulk and size-dependent. We demonstrate that the average static electric dipole polarizability of Na clusters depends linearly on the mean interatomic distance and only to a minor extent on the detailed ionic configuration when the overall shape of the electron density is enforced by electronic shell effects. The polarizability is thus a sensitive indicator for thermal expansion. We …

Lattice-Boltzmann and finite difference simulations for the permeability of three-dimensional porous media

2002

Numerical micropermeametry is performed on three dimensional porous samples having a linear size of approximately 3 mm and a resolution of 7.5 $\mu$m. One of the samples is a microtomographic image of Fontainebleau sandstone. Two of the samples are stochastic reconstructions with the same porosity, specific surface area, and two-point correlation function as the Fontainebleau sample. The fourth sample is a physical model which mimics the processes of sedimentation, compaction and diagenesis of Fontainebleau sandstone. The permeabilities of these samples are determined by numerically solving at low Reynolds numbers the appropriate Stokes equations in the pore spaces of the samples. The physi…

Comparative classical and ab initio Molecular Dynamics study of molten and glassy germanium dioxide

2008

A Molecular Dynamics (MD) study of static and dynamic properties of molten and glassy germanium dioxide is presented. The interactions between the atoms are modelled by the classical pair potential proposed by Oeffner and Elliott (OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compare our results to experiments and previous simulations. In addition, an ab initio method, the so-called Car-Parrinello Molecular Dynamics (CPMD), is applied to check the accuracy of the structural properties, as obtained by the classical MD simulations with the OE potential. As in a similar study for SiO2, the structure predicted by CPMD is only slightly softer than that resulting from the cl…

libvdwxc: A library for exchange-correlation functionals in the vdW-DF family

2017

We present libvdwxc, a general library for evaluating the energy and potential for the family of vdW-DF exchange--correlation functionals. libvdwxc provides an efficient implementation of the vdW-DF method and can be interfaced with various general-purpose DFT codes. Currently, the GPAW and Octopus codes implement interfaces to libvdwxc. The present implementation emphasizes scalability and parallel performance, and thereby enables \textit{ab initio} calculations of nanometer-scale complexes. The numerical accuracy is benchmarked on the S22 test set whereas parallel performance is benchmarked on ligand-protected gold nanoparticles ($\text{Au}_{144}(\text{SC}_{11}\text{NH}_{25})_{60}$) up to…

Ab initio modelling of UN grain boundary interfaces

2012

The uranium mononitride (UN) is a material considered as a promising candidate for Generation-IV nuclear reactor fuels. Unfortunately, oxygen in air affects UN fuel performance and stability. Therefore, it is necessary to understand the mechanism of oxygen adsorption and further UN oxidation in the bulk and at surface. Recently, we performed a detailed study on oxygen interaction with UN surface using density functional theory (DFT) calculations. We were able to identify an atomistic mechanism of UN surface oxidation consisting of several important steps, starting with the oxygen molecule dissociation and finishing with oxygen atom incorporation into vacancies on the surface. However, in re…