Search results for "CIM"
showing 10 items of 1625 documents
γ-ray induced GeODC(II) centers in germanium doped α-quartz crystal
2011
International audience; Main luminescence of α-quartz crystal doped with germanium results from the luminescence of a self-trapped exciton (STE) near germanium. In as grown Ge-doped α-quartz crystal, the luminescence associated with the twofold coordinated Ge center (GeODC) in amorphous silica glass doped with germanium, was never observed. In this work, we performed experiments to investigate if a GeODC like luminescence could appear after a γ-irradiation of a Ge-doped α-quartz crystal. The answer is positive: under excitation with pulsed light of an ArF laser (193 nm): a new luminescence with two bands -- a blue one associated to a time constant of about 100 μs appears and another one wit…
Introduction et dispersion d'une espèce envahissante : le cas de l'ambroisie à feuilles d'armoise (Ambrosia artemisiifolia L.) en France
2011
National audience; Ambrosia artemisiifolia L. (common ragweed) was accidentally introduced into France in the 1860s. Its single vector of introduction in Europe was red clover seeds (Trifolium pratense L.), probably coming from Pennsylvania, United States at the time. A. artemisiifolia was later introduced into France in many places and at different times. This species has no natural or effective seed dispersal mechanisms and the spread of this weed in the territory is ensured by human activities that carry the seeds and create disturbed environments favourable to its development. It is now established in the Rhone Valley and a number of different factors (cropping system evolution, climate…
Eight microsatellite markers isolated from common ragweed (Ambrosia artemisiifolia L.) and cross-amplification with herbarium specimens
2009
; Eight microsatellite markers were developed for population genetic analyses of the common ragweed, Ambrosia artemisiifolia. Markers were tested for amplification with three populations (two recent populations from France and North America, and one historical population from herbarium specimens). These loci revealed a high level of genetic variability (5-19 alleles per locus; expected heterozygosity, 0.48-0.92). No significant deviation from Hardy-Weinberg equilibrium and no linkage disequilibrium were observed. The data thus demonstrate their utility as efficient genetic markers for determining the genetic diversity, population differentiation, and gene flow among invasive, native, and h…
Modéliser les couverts cultures : adventices pour étudier le rôle de la diversification des cultures dans les systèmes de culture agro écologiques
2019
National audience; La diversification des cultures est un levier majeur de gestion agroécologique des bioagresseurs. Ce papier illustre avec l'exemple de FLORSYS le rôle des modèles mécanistes de dynamique des adventices pour synthétiser les connaissances, les appliquer à la conception de systèmes de culture, et les transférer vers les acteurs. Des cas d'étude illustrent comment ce modèle sert à évaluer et promouvoir les bénéfices de la diversification des cultures en (1) identifiant les caractéristiques de cultures qui seraient idéales ("idéotypes") pour la gestion agroécologique des adventices, (2) traquant des stratégies de gestion basées sur la diversification des cultures dans des rése…
Le cimetière du second Âge du fer de la Tournière à Lailly (Yonne) : nouvelle analyse des fouilles anciennes
2021
International audience; Cette étude présente de manière critique les découvertes qui ont été faites à la fin du xix e siècle et au début du xx e siècle à Lailly La Tournerie (Yonne). Elle propose un classement typologique et chronologique de tous les objets mis au jour par catégorie fonctionnelle, ainsi que la reconstitution, pour la première fois, de plusieurs ensembles clos. Elle a ainsi permis de proposer une évolution de ce cimetière entre le second quart du v e siècle (La Tène A ancienne) et la première décennie du ii e siècle avant J.-C. (La Tène C1). L'analyse des pratiques funéraires a également été abordée à l'aide d'un dépouillement systématique des rares données existantes. Leur …
Study of parameters endogeneous and exogeneous to ordinary Portland ciment influencing hydration of its main phase : tricalcium silicate
2012
This work devoted to study various parameters influencing hydration of silicate phase main Ordinary Portland Cement (OPC) was performed at the Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB). This study is part of the project "Crystal Growth Control" initiated by BASF in order to monitor and provide the best as possible the hydration of Ordinary Portland Cement. The dissolution of alite, like the pure C3S one, is fast in pure water. Speed decreases with deviation from equilibrium and the concentration of aluminates ions in solution. There is also an adsorption on the surface of the aluminum which is into the alite and released by dissolution. Germination and growth of C-S-H has bee…
Characterisation of mechanical behavior of a sub surface drilled polymer, under hertzian contact load
2013
This research concerns the understanding of the sub-surface behaviour of a component presenting controlled heterogeneities and subjected to a Hertzian type load. The purpose is to qualify the stress field in the subsurface. Practically, defects of cylindrical shape are located where the stress field is maximal in sub surface. The contact is sized to be able to observe, by photoelasticity, the stress field and to develop a numerical model to simulate the behaviour (static and dynamic) of the friction area. It is highlighted that the presence of a hole on the z axis of symmetry (x = 0) is the dominating factor. The characteristics which allow decreasing the shearing stress on the symmetry axi…
Etude expérimentale et modélisation thermodynamique du système CaO-SiO2-(Al2O3)-H2O
2012
The aim of this work is to build a thermodynamic model at 25°C to describe the main hydrates of ordinary Portland cement with or without supplementary cementitious materials (SCM) : calcium hydrosilicates. With high aluminium content, SCM in blended cements modify the nature and the composition of the hydrates of cement paste.The simplified model system CaO-SiO2-H2O was studied by synthesising of C-S-H with identical protocol and analysis. We distinguished, hydration solutions undersaturated and supersaturated from Portlandite.This last system has been extended to CaO-Al2O3-SiO2-H2O system. Then, we determined the most suitable protocol to synthesize pure C-A-S-H.The nanoparticular nature a…
Rapid Compression Machine. 2013.
2013
A rapid compression machine is a type of ideal internal combustion reactor which is well suited for gas phase kinetics studies and physical processes of combustion. These studies consist in recording the evolution of the reactivity and of the composition of the reacting mixtures as a function of temperature, pressure, residence time and the composition of the compressed mixture. Pressure measurement is used to analyse the evolution of the combustion process, but more recent studies couple pressure measurement with optical diagnostics in order to assess the homogeneity of the combustion process. Speciation based on rapid sampling of the intermediates formed, during the oxidation of the fuel,…
Resiliencia en el consumo de agua por parte de abastecimientos y regadíos ante las sequías en el Sureste de España
2020
El objeto de estudio es analizar y comparar cómo responden regantes y abastecimientos a situaciones de sequía en el Sureste de España en el siglo XXI, con el ejemplo de las de 2005-2008 y 2017-2018. Metodológicamente es un estudio de geografía regional con análisis cualitativo y cuantitativo, diacrónico y comparado, y trabajo de campo. Entre las fuentes utilizadas sobresalen la consulta de archivos históricos, los datos de AEMET, los consumos de agua en abastecimientos y regadíos, y las entrevistas a gestores y usuarios. La respuesta ante las sequías del siglo XXI ha sido dispar. En la de 2005-2008, en el regadío hubo que reducir la superficie de arbolado; en abastecimientos, se recurrió a …