Search results for "Spar"
showing 10 items of 1739 documents
SPS-assisted preparation of the Magnéli phase WO2.90 for thermoelectric applications
2013
We describe the preparation and simultaneous consolidation of WO2.90 by spark plasma sintering (SPS). SPS allows for the direct manufacturing of large amounts of consolidated material. Synchrotron powder X-ray diffraction indicates that the material is single phase. Microstructure analysis indicates that the pellet is fully dense, allowing high-temperature thermoelectric properties to be reliably measured. The as-prepared samples of WO2.90 reach a ZT of 0.1 at 1100 K.
Sparse Image Representation by Directionlets
2010
Despite the success of the standard wavelet transform (WT) in image processing in recent years, the efficiency and sparsity of its representation are limited by the spatial symmetry and separability of its basis functions built in the horizontal and vertical directions. One-dimensional discontinuities in images (edges or contours), which are important elements in visual perception, intersect too many wavelet basis functions and lead to a non-sparse representation. To capture efficiently these elongated structures characterized by geometrical regularity along different directions (not only the horizontal and vertical), a more complex multidirectional (M-DIR) and asymmetric transform is requi…
Nonlinear diffusion in transparent media: the resolvent equation
2017
Abstract We consider the partial differential equation u - f = div ( u m ∇ u | ∇ u | ) u-f=\operatornamewithlimits{div}\biggl{(}u^{m}\frac{\nabla u}{|\nabla u|}% \biggr{)} with f nonnegative and bounded and m ∈ ℝ {m\in\mathbb{R}} . We prove existence and uniqueness of solutions for both the Dirichlet problem (with bounded and nonnegative boundary datum) and the homogeneous Neumann problem. Solutions, which a priori belong to a space of truncated bounded variation functions, are shown to have zero jump part with respect to the ℋ N - 1 {{\mathcal{H}}^{N-1}} -Hausdorff measure. Results and proofs extend to more general nonlinearities.
Unary Languages Recognized by Two-Way One-Counter Automata
2014
A two-way deterministic finite state automaton with one counter (2D1CA) is a fundamental computational model that has been examined in many different aspects since sixties, but we know little about its power in the case of unary languages. Up to our knowledge, the only known unary nonregular languages recognized by 2D1CAs are those formed by strings having exponential length, where the exponents form some trivial unary regular language. In this paper, we present some non-trivial subsets of these languages. By using the input head as a second counter, we present simulations of two-way deterministic finite automata with linearly bounded counters and linear–space Turing machines. We also show …
L'équité : un fil rouge des politiques éducatives nationales
2014
This paper aims to cover some at least of the most significant dimensions that can help document, based on a sampling of countries, the issues surrounding equity and children's right to attend school, to stay in school long enough and to receive appropriate education services to ensure access to adult life with the basic knowledge and skills that will give them a chance at a decent economic and social life. Above and beyond its quantitative observations, this analysis identifies connections with various active or passive education policies found in national education systems. Additionally,to the extent that they provide a better understanding of the situation and point out stumbling blocks …
Social disparities in students’ trajectories to French « grandes écoles »
2021
International audience
Mobilités géographiques étudiantes et qualifications des territoires : quelques disparités régionales
2003
Depuis les lois de décentralisation, depuis le dernier plan de redéploiement « Université 2 000 », le niveau régional a acquis une nouvelle légitimité non seulement en tant que niveau d'observation des structurations de l'offre de formation supérieure et des marchés de l'emploi mais aussi et surtout comme territoire de revendications et d'actions.Or, les situations régionales liées aux popul; Depuis les lois de décentralisation, depuis le dernier plan de redéploiement « Université 2 000 », le niveau régional a acquis une nouvelle légitimité non seulement en tant que niveau d'observation des structurations de l'offre de formation supérieure et des marchés de l'emploi mais aussi et surtout co…
Querying Dynamic and Context-Sensitive Metadata in Semantic Web
2005
RDF (core Semantic Web standard) is not originally appropriate for context representation, because of its initial focus on the ordinary Web resources, such as web pages, files, databases, services, etc., which structure and content are more or less stable. However, on the other hand, emerging industrial applications consider e.g. machines, processes, personnel, services for condition monitoring, remote diagnostics and maintenance, etc. to be specific classes of Web resources and thus a subject for semantic annotation. Such resources are naturally dynamic, not only from the point of view of changing values for some attributes (state of resource), but also from the point of view of changing “…
NMDA receptor antagonist treatment increases the production of new neurons in the aged rat hippocampus
2002
The production of new neurons declines during adulthood and persists, although at very low levels, in the aged hippocampus. Since neurogenesis in young adults has been related to learning and memory, its reduction may contribute to the age-related impairments in these abilities. Adrenalectomy (ADX) enhances neurogenesis in the aged hippocampus, although it also induces neuronal cell death. Since the administration of an NMDA receptor antagonist enhances neurogenesis in young adult rats without deleterious morphological effects, we have tested whether neurogenesis could be reactivated in aged rats. Our study shows that cell proliferation, cell death, neurogenesis and the number of radial gli…
Determination of Pareto frontier in multi-objective maintenance optimization
2011
Abstract The objective of a maintenance policy generally is the global maintenance cost minimization that involves not only the direct costs for both the maintenance actions and the spare parts, but also those ones due to the system stop for preventive maintenance and the downtime for failure. For some operating systems, the failure event can be dangerous so that they are asked to operate assuring a very high reliability level between two consecutive fixed stops. The present paper attempts to individuate the set of elements on which performing maintenance actions so that the system can assure the required reliability level until the next fixed stop for maintenance, minimizing both the globa…