Search results for "LCA"

Selective reflection spectroscopy of alkali vapors confined in nanocells and emerging sensing applications

2019

This thesis is aimed at studying the resonant interaction of a laser radiation with an atomic alkali vapor layer of wavelength-scale thickness confined in an optical nanocell; and emerging sensing applications.We focus our attention on the selective reflection arising at the interface between a dielectric window and a resonant alkali vapor, and show that the derivative of selective reflection spectra exhibit narrow resonances whose maxima are located exactly at atomic resonance frequencies. These resonances are observed with a spectral linewidth up to fifteen times smaller than the Doppler linewidth of the medium and their amplitudes scale linearly with respect to the transitions ones. Owin…

Le désherbage d’automne contre l’ergot du seigle les traitements herbicides d’automne, un levier chimique efficace de lutte contre l’ergot du seigle

2013

Context and study: Trials in field allowed to show a link between a good grass weeding (blackgrass and rye grass) and extent of ergot contaminations. Makhteshim Agan France and Arvalis tested on 15 trials in 2011-2012, 2 ureas, as isoproturon against blackgrass, alone or in pro-gram with a sulfonylurea, to evaluate their indirect effect against ergot. Field trials were set up on sensitive crops to ergot (rye, wheat and triticale) infested with artificial ergot contaminations and weed seeds sensible to ALS. Contaminations were evaluated first in field on weeds and on crop, and then on harvest, by assessing sclerotia and alkaloids content in harvested samples. results: For all evaluation mean…

Magma-derived gas influx and water-rock interactions in the volcanic aquifer of Mt. Vesuvius, Italy

2002

We report in this paper a systematic investigation of the chemical and isotopic composition of groundwaters flowing in the volcanic aquifer of Mt. Vesuvius during its current phase of dormancy, including the first data on dissolved helium isotope composition and tritium content. The relevant results on dissolved He and C presented in this paper reveal that an extensive interaction between rising magmatic volatiles and groundwaters currently takes place at Vesuvius.Vesuvius groundwaters are dilute (mean TDS ∼ 2800 mg/L) hypothermal fluids ( mean T = 17.7°C) with a prevalent alkaline-bicarbonate composition. Calcium-bicarbonate groundwaters normally occur on the surrounding Campanian Plain, l…

Isotope geochemistry of Pantelleria volcanic fluids, Sicily Channel rift: a mantle volatile end-member for volcanism in southern Europe

2000

Chemical and isotopic ratio (He, C, H and O) analysis of hydrothermal manifestations on Pantelleria island, the southernmost active volcano in Italy, provides us with the first data upon mantle degassing through the Sicily Channel rift zone, south of the African–European collision plate boundary. We find that Pantelleria fluids contain a CO2–He-rich gas component of mantle magmatic derivation which, at shallow depth, variably interacts with a main thermal (∼100°C) aquifer of mixed marine–meteoric water. The measured 3He/4He ratios and δ13C of both the free gases (4.5–7.3 Ra and −5.8 to −4.2‰, respectively) and dissolved helium and carbon in waters (1.0–6.3 Ra and −7.1 to −0.9‰), together wi…

Apports des données Aladin dans le cadre d'une prévision de l'ozone troposphérique en Bourgogne

2003

Le CRC et les réseaux de surveillance de la qualité de l'air ATMOSF'air Bourgogne Centre-Nord et Sud élaborent un outil de prévision au lendemain de la pollution à l'ozone troposphérique. L'objectif est de prévoir les concentrations maximales quotidiennes à l'aide de modèles statistiques exploitables par les réseaux. Ces modèles considèrent des précurseurs de l'ozone, mesurés le jour où est effectuée la prévision, et les conditions météorologiques du jour pour lequel est effectuée la prévision. Une première étape fut d'étudier la prévisibilité de l'ozone à partir d'observations météorologiques ou « prévisions météorologiques parfaites ». Une seconde fut de réaliser de véritables prévisions.…

Les précipitations au Proche-Orient : variabilité spatio-temporelle et relations avec la dynamique de l'atmosphère (1960-1961 - 1989-1990)

2004

Thèse de Doctorat, Université de Bourgogne

Simulation des sorties d'eau et de nitrates de parcelles agricoles drainées. Cas du site expérimental de Virey-le-Grand (71)

2003

Signatures terrigène et volcanique des bassins sédimentaires : implications stratigraphiques et paléoclimatiques

2018

Volcanisme explosif aérien au passageCarbonifère-Permien dans les bassinsstéphano-autuniens d’Europe de l’Ouest

2016

National audience; Les bassins stéphano-autuniens d’Europe de l’Ouest, associésà un régime d’extension post-orogénique, ont enregistrésde fréquentes manifestations volcaniques. Ces évènements sonttoutefois encore relativement peu étudiés et datés en particulierdans les bassins sédimentaires bordant le Massif Central. Uninventaire des épisodes volcaniques associés aux retombées decendres est établi, dans l’optique de préciser la nature du volcanisme,la localisation des sources et fournir des âges radiométriquesU-Pb. Ces âges numériques sont fondamentaux pour calibrer lesséries sédimentaires continentales européennes et les corréler auxéquivalents temporels des séries marines d’Asie ou des Et…

Phase equilibrium constraints on the production and storage of peralkaline silicic magmas: insights from Kenya and Pantelleria.

2005

The origin of peralkaline silicic rocks is still obscure and stands perhaps as one of the last major unsettled issues in classic igneous petrology. The debate goes back to the end of the 18th century and despite intensive petrological, geochemical and laboratory efforts the consensus has yet to emerge as to which mechanisms produce peralkaline derivatives. Bowen (1937) first proposed that the shift from metaluminous to peralkaline field was due to extensive fractionation of calcic plagioclase. Perhaps the best illustration of such an hypothesis is provided by the Boina rock series in the Ethiopian rift studied by Barberi et al. (1975). However, such an hypothesis still awaits experimental c…