Дисертації з теми "Distributions de temps de résidence"
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Poumaere, Nelson. "Transport et Temps de résidence dans les écoulements ouverts, chaotiques ou perturbés." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2023. http://www.theses.fr/2023ECDL0057.
This work is concerned with the transport properties of open flows perturbed as a result of a hydrodynamic instability. Direct numerical simulation of stationary and pulsatile channel flows allows us to compute residence time distributions (RTD) corresponding to their perturbed states and thus to finely characterize their transport properties.In the first part of the study, and following the results of Raynal & Carrière (2015), in-line chaotic mixers are considered and statistical tools used throughout the whole thesis to measure RTDs’ widths are introduced. In particular, the use of the mean absolute deviation instead of the standard deviation is justified in the case of the heavy-tailed distributions at hand.The second part of this work deals with the plane Poiseuille flow in which finite-amplitude Tollmien–Schlichting waves are propagating. Comparison of RTDs for base and perturbed flows leads to the following two observations : first, a probability peak located at the “wave residence time” appears due to the advection of particles by the propagating vortices ; second, the mean flow correction leads to a decreased minimum residence time and thus to an increased width of the RTD.In the final part, the pulsatile channel flow in nonlinear instability regimes is considered. Depending on the frequency and the amplitude of the pulsation, the two resulting nonlinear regimes — cruising and ballistic (Pier & Schmid, 2017) — lead to drastically different chaotic behaviours. It is shown that the ballistic regime displays the best mixing capabilities, even though it is less energetic. By computing the RTDs corresponding to these two regimes and those of the basic Womersley profile, the ballistic regime is also identified as the one which leads to the least increased width of the RTD. In the framework of the present study, this regime is thus the closest to an ideal mixer : it combines efficient mixing and low RTD width at moderate energy cost
Courbebaisse, Guy. "Distributions temps-fréquence et temps-échelle : contributions au domaine des machines thermiques." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0050.
Ayraud, Virginie. "Détermination du temps de résidence des eaux souterraines : application au transfert d'azote dans les aquifères fracturés hétérogènes." Phd thesis, Université Rennes 1, 2005. http://tel.archives-ouvertes.fr/tel-00088100.
L'hydrochimie de ces aquifères est fortement liée à l'hétérogénéité physique des roches avec une variabilité spatiale beaucoup plus grande que la variabilité temporelle dans ces bassins-versants. Dans ces milieux, le cycle de l'azote et du soufre sont intimement liés au travers de la dénitrification par oxydation des sulfures. La potentialité d'une dénitrification par oxydation du fer dans les roches cristallines a été mise en évidence au travers d'expérimentations en batch. L'interprétation des données concernant les isotopes du soufre et de l'oxygène des sulfates montrent une cohérence entre la localisation spatiale et le processus mis en jeu quel que soit le site étudié. L'ensemble de ces résultats met en avant l'existence dans la zone profonde de ces aquifères, de solutés d'origine ancienne conservés dans la microporosité et qui contribuent à la chimie des eaux circulant dans les fractures connectées à cette microporosité.
Ces aquifères peuvent être décomposés en trois compartiments principaux que sont les zones de recharge, la zone altérée et la zone profonde. Dans chacun de ces compartiments les temps de résidence sont homogènes à l'échelle de la Bretagne : eaux récentes dans les zones de recharge, eaux anciennes (>50 ans) dans la zone profonde et un temps de résidence moyen de 18 ± 2 ans dans la zone altérée. Ces données indiquent que la gestion de ces aquifères doit prendre en compte l'échelle du temps de résidence de l'eau dans la zone altérée, réservoir de soutien des cours d'eau (supérieur à la dizaine d'années).
Hachet, Benoît. "La résidence alternée : une sociologie de l'expérience temporelle des parents." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEH113.
Shared residence, legalized in France in 2002, is a minority practice that affects all categories of the population of separated parents. It is strictly understood as an arrangement in which the residence times of children is equally shared between their two parents. According to the principle of coparental symmetry, the parents’ experience of time is bichronic, marked by the repeated succession of periods of time of equal length, some with children and others without. We explore the temporal experience of this alternate parenthood using a mixed method that combines the analysis of 55 interviews and 5,103 questionnaires sent to French Family Allowance Fund who have children in shared residence. The first part contextualizes the question of shared residence in contemporary France. The thesis maps the controversies it raises, specifies the legal developments and judicial modalities of its implementation, before noting that existing studies on this subject are few and often partial. While the social and economic determinants of the choice of shared residence are fairly well known, the concrete functioning of alternating residence is not well studied. Our research adopts a temporalistic perspective that consists in questioning the differentiated times of human experience. In the second part we characterize the general economy of the temporal framework of alternate residence, showing that the equal sharing of residence times cannot escape the dominant calendar time. The two spaces created in these conditions are constituted into temporal territories over which each parent exercises relative sovereignty according to rules that are built incrementally. We propose a topology of the territories of alternation, attentive to their structure and plasticity. In the third part, we consider the parental experience of time sequences with and without children by first specifying the differences in temporal texture, before describing the modalities of time harmonization. We conclude by looking at the issue from a long term perspective to question the evolution of the parental experience of alternation over time, when it is confronted with events such as family reconstitution or professional mobility. Throughout the thesis, we are attentive to variations in the organization and temporal experience of shared residence according to major sociological variables, gender, age, social background or parents' place of residence
Hory, Cyril. "Mélanges de distributions du X2 pour l'interprétation d'une représentation temps-fréquence." Grenoble INPG, 2002. http://www.theses.fr/2002INPG0145.
Time-Frequency Representations (TFR) of a non-stationary signal display its energy content along both time and frequency dimensions. One can show that the statistical behaviour of the time-frequency coefficients is lead by central and non-central chi2 distributions. The aim of this work is to include such tools in a general process of automatic interpretation of the analyzed signal. It consists in localizing and characterizing the energetic content of TFR structures called spectral patterns. The interpretation problem is thus reduced to a classification problem from a mixture of chi2 modeling. Two approaches are proposed. The first method consideres* a global mixture model of the TFR. Characteristic parameters are estimated by means of an Expectation-Maximization algorithm especially designed for a chi2 mixture. The classification step is then realized by a likelihood ratio testing. In the second method, the mixture modeling provides a local description of the TFR. Statistical features are extracted from a gliding cell. The projection of the TFR to the so-called Features Space (FS) allows to discriminate the time-frequency structures by means of a region growing algorithm. The characteriz tion step is then realized by applying the moment method to a polynomial regression of clusters associated to spectral patterns in the FS. The nature of information provided by both of the methods is discussed. Pertinency for a non-stationary signal interpretation is compared with synthetic and natural data
Leray, Sarah. "Caractérisation des aquifères de socle cristallin et de leur ressource en eau - Apport des données d' " âge " de l'eau." Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00829278.
Ben, Maamar Sarah. "Biodiversité des eaux souterraines dans un gradient de temps de résidence et d'influence anthropique : approches métagénomique et géochimique couplées." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S108/document.
Hard-rock aquifers are heterogeneous geological structure very widespread in Britany that have the property to store groundwater. These aquifers are often made of a weathered zone and a fractured zone. The weathered zone is a rather thin layer close to the surface and is constituted of weathered rocks submerged in groundwater. In this zone, groundwater circulates rapidly from the upper parts of the watershed to the aquifer outlet, thus shows short groundwater residence time (< 20y) and is often polluted by nitrates. The fractured zone is located deeper and is thicker. It is composed of fresh rocks crossed by fractures in which groundwater exclusively flows with a very slow velocity, thus groundwater residence time in this zone is rather long (>40 y). In the fractured zone, groundwater is much more mineralized and often rich in iron, in Britany. The differences of flow velocities in the weathered and the fractured zones are responsible for contrasted chemical conditions in these two zones, but the influence of groundwater flow velocity on the microbial ecosystem in groundwater remains largely unexplored. This work shows hydrologic circulations influence the microbial community structuration in hard-rock aquifer groundwater at regional and local scales. Position of a groundwater along a hydrologic flowpath or a “hydrological loop” directly controls microbial community structure through the control of the successively available electron donors and acceptors. The analyzed microbial communities show a predominance of Betaproteobacteria. In recent groundwater (< 20y) thus particularly in the weathered zone, Betaproteobacteria are mainly Comamonadaceae and Oxalobacteraceae, which are generalists able to do denitrification. In old and isolated groundwater (> 40y) thus particularly in the fractured zone, Betaproteobacteria are mainly Gallionellaceae, which are microaerophilic iron-oxidizer. The predominance of Gallionellaceae in the fractured zone suggests a deep ecosystem based on iron oxidation. However, this process implies a minimal input of oxygen in the deeper part, for instance via mixing with recent oxygenated groundwater. Proportion of Gallionellaceae in the different analyzed groundwater shows a positive correlation with the degree of mixing between old and recent groundwater, up to a limit of 20% of recent groundwater. The temporal microbial community dynamics in a single aquifer, before and during the beginning of recharge, demonstrated in the weathered part very fluctuant chemical conditions and a shifting microbial community that remains always composed of numerous potential denitrifiers. In the fractured part, microbial community is dominated by Gallionellaceae and remains rather stable, despite the punctual but substantial changing of the chemical conditions and degree of mixing (up to 60% of recent groundwater) at the beginning of the recharge. Gallionellaceae seem thus able to resist to important and punctual chemical conditions changings. Groundwater in the deeper part of aquifers, even isolated, remains relatively connected to surface, likely allowing the deep microbial ecosystem to maintain
Kalla, Hamoudi. "Génération automatique de distributions/ordonnancements temps réel, fiables et tolérants aux fautes." Phd thesis, Grenoble INPG, 2004. http://tel.archives-ouvertes.fr/tel-00008413.
Personeni, Emmanuelle. "Dynamique du carbone et de l'azote lors de la décomposition in situ de litières racinaires de graminées prairiales." Paris 6, 2004. http://www.theses.fr/2004PA066263.
Devedeux, Dominique. "Évaluation quantitative de certaines caractéristiques de distributions temps/fréquence : application à l'EMG utérin." Compiègne, 1995. http://www.theses.fr/1995COMPD789.
Guri, Shipé. "Les hôtels aristocratiques à Bruxelles (1600-1730): Etude sociale, spatiale, économique et symbolique d'un enracinement nobiliaire en ville." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/294233/3/these.pdf.
Doctorat en Histoire, art et archéologie
info:eu-repo/semantics/nonPublished
Péron-Cane, Caroline. "Suivi en temps réel des protéines bactériennes sécrétées." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS314.
Upon infection, bacterial pathogens deploy an arsenal of virulence factors promoting the invasion of their host organisms. Although these bacterial effectors have been well characterized, the dynamics of their secretion and of their intracellular localization in the host remain poorly described due to the lack of appropriate tools allowing their visualization in real time. Indeed, common fluorescent tags like GFP (Green Fluorescent Protein) are thought inactive after transport through bacterial secretion systems. To overcome these limitations, we took advantage of FAST (Fluorescence-Activating and absorption Shifting Tag), a tunable fluorescent probe where the fluorescence results from the rapid association with a membrane-permeant fluorogenic ligand. In this work, we showed that FAST can be used to visualize effectors secreted by several bacterial secretion systems (T3SS, T5SS and Sec). By measuring FAST secretion, we quantified the dynamics of formation and rupture of internalization vacuoles occupied by Listeria monocytogenes. Monitoring the location of LLO, a major virulence factor secreted by L. monocytogenes during invasion of epithelial cells, we identified a compartment in which bacteria can replicate, before colonizing the host cytoplasm. In addition to validating a fluorescent tool to monitor the real-time localization of bacterial proteins exported by various secretion systems, this study updates the model of the intracellular cycle of L. monocytogenes during epithelial cell infection
Boër, Marie. "Etude des Distributions de Parton Généralisées avec la Diffusion Compton Profondément Virtuelle "genre espace" et "genre temps"." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112372/document.
More than forty years after the discovery of pointlike constituents inside the nucleon, its quarks and gluons structure is still intensively studied. Some exclusive processes (where all the final state products are known) of leptoproduction or of photoproduction of photon or meson off the nucleon provide access to the Generalized Parton Distributions (GPDs). These functions parameterize the complex structure of the nucleon and contain informations about the longitudinal momentum and the spatial transverse distribution of partons inside the nucleon. Such exclusive processes are the "Spacelike" and the "Timelike" Deeply Virtual Compton Scattering processes (DVCS and TCS respectively) which correspond to the scattering of a high-energy photon off a quark in the nucleon and are respectively measured in the reactions lN⇾l'N'γ (N = proton or neutron, l' = lepton) and γN⇾N'l+l- The first part of this thesis is devoted to the experimental study of DVCS, using the 2009 data from the COMPASS experiment at CERN. In a first step, the Deep Inelastic Scattering cross section is measured in order to check the muon flux measurement and to evaluate some systematic effects. Then, the cross section for the exclusive production of a photon is measured. It is made up of the DVCS process (the photon is emitted by a quark) and of the Bethe-Heitler process (the photon is emitted by the scattered lepton) which has the same final state. The study of the background has allowed to estimate in parallel an upper limit for the cross section of the exclusive production of a π° meson. The second part of the thesis is devoted to a phenomenological study of TCS at typical energies for the JLab 12 GeV upgrade. Firstly, the amplitudes for the TCS and for the associated Bethe-Heitler process are derived. Then, all single and double polarization (beam and/or target) observables are calculated as a function of different GPD contributions. Finally, a method is presented to extract the Compton Form Factors (functions of GPDs) from fits on DVCS and/or TCS data and/or simulations
Aleiyouka, Mohalilou. "Sur la dépendance des queues de distributions." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMLH28/document.
The modeling of the dependence between several variables can focus either on the positive or negative correlation between the variables, or on other more effective ways, which determine the tails dependence of distributions.In this thesis, we are interested in the tail dependence of distributions, by presenting some properties and results. Firstly, we obtain the limit tail dependence coefficient for the generalized hyperbolic law according to different parameter values of this law. Then, we exhibit some properties and results of die extremal dependence coefficient in the case where the random variables follow a unitary Fréchet law.Finally, we present a Real Time Database ManagementSystems (RDBMS). The goal is to propose probabilistic models to study thebehavior of real-time transactions, in order to optimize its performance
Marçais, Jean. "Variabilités des temps de résidence de l’eau et du débit dans les rivières et les nappes phréatiques : implications sur la qualité de l’eau : inférence, modélisation et prédiction des temps de transit de l’eau dans les bassins versants." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B025/document.
Groundwater travel time controls contaminant transport, weathering processes and biogeochemical cycles. Groundwater travel time is a fundamental descriptor characterizing the transit time of water inside the catchment, from precipitation events to the streams. Quantifying these transit times is pivotal to predict the impact of anthropogenic pressure and assess freshwater ecosystems resilience. However, streamwater and groundwater are a mixture of water of different ages (the transit time and the residence time distribution), which vary according to climatic forcings. This makes difficult its characterization and prediction. Here we infer residence times with geochemical tracers and data-driven models. We show how this can be constrained by silicate weathering at the catchment scale. We then develop a novel process-based framework, which can model discharge and transit time seasonal and interannual variabilities. We identify water table fluctuations, its interaction with permeable soil layers and the resulting subsurface stormflow generation as a key process for seasonal water quality variations described by dissolved silica measurements. Finally, we draw a reactivity framework to represent biogeochemical processes. Indeed, evaluating reactive solute degradation is needed to assess the efficiency of reducing fertilizer loads, to predict the long term evolution of in stream solute concentrations and the eutrophication potential of freshwater bodies. Modeling the reactivity at the catchment scale is the missing link to understand, quantify and predict the effect of anthropogenic pressure on the critical zone
Sassine, Lara. "Occurrence des pesticides et des contaminants émergents dans une nappe alluviale. Contraintes apportées par l’origine et le temps de résidence de l’eau. Cas de la nappe de la Vistrenque." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4355.
The aim of this work is to test a multi-tracer approach allowing the characterization of groundwater origin and residence time in a shallow alluvial aquifer, the Vistrenque aquifer, in order to identify the origin and the fate of contaminants therein. The selected compounds for the study are triazines, metolachlor, diuron, carbamazepine, sulfamethoxazole, diclofenac, and ibuprofen. The studied aquifer is mainly fed by 1) a direct recharge inducing pesticides leaching from soil layers and unsaturated zone and 2) by a lateral recharge from the karst adjacent aquifer, which induces triazines dilution in the alluvial aquifer. A local contribution of surface water (local streams and imported Rhône River water) was evidenced in the alluvial groundwater inducing also triazines dilution but EOCs contamination nevertheless at low concentrations. The apparent age of the alluvial groundwater samples varies between 1.4 and 22 years. Linking groundwater age to triazines contents allowed to highlight, first, the persistence of these compounds in the alluvial groundwater and, second, the decreasing of their input signal in relatively recent groundwater samples in accordance with their forbidding in 2003. Finally, the Vistrenque alluvial groundwater showed triazines degradation ratios varying from 0.3 for groundwater influenced by surface water infiltration to 4.8 for groundwater characterized by relatively older apparent residence time on the order of 22 years. This suggests an increasing ratio with the transfer time of these compounds in the alluvial aquifer system
Fabbro, Gareth Nicholas. "The timescales of magmatic processes prior to a caldera-forming eruption." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22452/document.
Large, explosive, caldera-forming eruptions are amongst the most destructive phenomena on the planet, but the processes that allow the large bodies of crystal-poor silicic magma that feed them to assemble in the shallow crust are still poorly understood. Of particular interest is the timescales over which these reservoirs exist prior to eruption. Long storage times—up to 105 y—have previously been estimated using the repose times between eruptions and radiometric dating of crystals found within the eruptive products. However, more recent work modelling diffusion within single crystals has been used to argue that the reservoirs that feed even the largest eruptions are assembled over much shorter periods—101–102 y. In order to address this question, I studied the >10km3, 22-ka, dacitic Cape Riva eruption of Santorini, Greece. Over the 18 ky preceding the Cape Riva eruption a series of dacitic lava dome and coulées were erupted, and these lavas are interspersed with occasional dacitic pumice fall deposits (the Therasia dome complex). These dacites have similar major element contents to the dacite that was erupted during the Cape Riva eruption, and have previously been described as “precursory leaks” from the growing Cape Riva magma reservoir. However, the Cape Riva magma is depleted in incompatible elements (such as K, Zr, La, Ce) relative to the Therasia magma, as are the plagioclase crystals in the respective magmas. This difference cannot be explained using shallow processes such as fractional crystallisation or crustal assimilation, which suggests that the Cape Riva and Therasia magmas are separate batches. Furthermore, there is evidence that the Therasia dacites were not fed from a long-lived, melt-dominated reservoir. There are non-systematic variations in melt composition, plagioclase rim compositions, and plagioclase textures throughout the sequence. In addition, high-temperature residence times of plagioclase and orthopyroxene crystals from the Therasia dacites estimated using diffusion chronometry are 101–102 y. This is short compared to the average time between eruptions (1,500 y), which suggests the crystals in each lava grew only shortly before eruption. The different incompatible element contents of the Cape Riva and Therasia magmas and plagioclase crystals suggest that a new batch of incompatible-depleted silicic magma arrived in the shallow volcanic plumbing system shortly before the Cape Riva eruption. This influx must have taken place after the last Therasia eruption, which 40Ar/39Ar dates show occurred less than 2,800±1,400 years before the Cape Riva eruption. The rims of the plagioclase crystals found in the Cape Riva dacite are in equilibrium with a rhyodacite, with a similar composition to the Cape Riva glass. However, the major and trace element zoning patterns of the crystals record variations in the melt composition during their growth. The compositions at the centre of most crystals are the same as the rims; however, these crystals are often partially resorbed and overgrown by more calcic plagioclase. The plagioclase then grades normally back to rim compositions. This cycle is repeated up to three times. The tight relationships between the anorthite, Sr and Ti contents of the different zones suggests that the composition of the plagioclase crystals correlates with the composition of the melt from which theygrew. The different plagioclase compositions correspond to dacitic and rhyodacitic melt compositions. The orthopyroxene crystals reveal a similar sequence, although they only record one cycle. These zoning patterns are interpreted to document the assembly of the Cape Riva reservoir in the shallow crust through the amalgamation of multiple batches of compositionally diverse magma. Models of magnesium diffusion in plagioclase and Fe–Mg interdiffusion in orthopyroxene suggest that this amalgamation took place within 101–102 y of the Cape Riva eruption
Landès, Matthieu. "Utilisation des corrélations du bruit en sismologie : tomographie passive et étude de distributions de sources de bruit." Paris, Institut de physique du globe, 2009. http://www.theses.fr/2009GLOB0012.
Recent studies show the possibility to extract the Green’s function between two locations by correlating a random wavefield recorded by receivers located at these points. Applied to seismology, the feasibility of this approach is illustrated by the study of ambient seismic noise correlations during long periods that results in reconstructing the “surface wave” part of Green’s functions. This provides us with a new way of passive imaging of the Earth structure by measuring and inverting velocities of seismic waves propagating between pairs of stations of a seismic network. However, applicability of this approach result is closely related to the properties of seismic noise that may be different in different regions. The research that I present consists of four separate studies. The first study aims to apply the technique of passive tomography in an oceanic environment to infer the structure of the lower crust and upper mantle below Iceland. The second study is based on observations of noise correlations containing signals that are not parts of the Green’s function but results from ballistic teleseismic body waves generated by distant oceanic storms. By applying a network analysis to these signals, we can locate their sources distribution and to determine unambiguously that they are preferentially generated in deep oceans. The third study examines the feasibility of using the seismic noise correlation at the seafloor to infer to the shear velocity distribution of the top 30 m. Finally, in addition to this seismic noise problem, I will present a final original study that shows the use of dispersion curves and Time-Frequency diagram to estimate the speed of earthquake rupture Koxokili of November 2001
Huneau, Frederic. "FONCTIONNEMENT HYDROGEOLOGIQUE ET ARCHIVES PALEOCLIMATIQUES D'UN AQUIFERE PROFOND MEDITERRANEEN Etude géochimique et isotopique du bassin miocène de Valréas (Sud-Est de la France)." Phd thesis, Université d'Avignon, 2000. http://tel.archives-ouvertes.fr/tel-00323650.
Drouzy, Marion. "Etude de l'impact terrigène naturel et anthropique sur un système lagonaire tropical grâce à une approche de modélisation 3D hydro-sédimentaire liée à un réseau de mesures." Electronic Thesis or Diss., Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0455.
This thesis presents the adaptation of a hydrodynamic model to the lagoon of New Caledonia, potentially impacted by nickel activity. Hydrodynamic modeling is a tool for estimating and managing spatiotemporal risks for downstream areas. The MARS3D model has been implemented to study the dispersion of a dissolved material (tracer) from rivers. The tracking of this tracer, under the influence of different physical forcings, made it possible to apprehend the fate of dissolved pollutants potential from the mining industry. A residence time characteristic of hydrodynamics, calculated using the model and called the local e-Flushing time (eFTs), has been proposed to determine the zones with the longest residence times, and therefore the prediction of stagnant areas of possible pollutants in the water column, depending on wind and tidal conditions. This indicator is a predictive information tool, easily and quickly exploitable in an approach to estimate pollution risks. The last phase of the thesis work was the implementation of the coupling between the existing hydrodynamic module and the sedimentary module. An important test phase of the various parameterization options was necessary to reproduce the sedimentary characteristics measured in situ. Several pieces of information remain missing, which makes it difficult to use the module for forecasting purposes. However, the influence of terrigenous inputs on the entire modeled domain has been highlighted, raising the potential pollution risks via fixation of contaminants on deposited particles
Wang, Xiaodong. "Modélisation et simulation numérique de la combustion en présence d’interactions flammes/auto-inflammation Interactions between mixing, flame propagation, and ignition in non-premixed turbulent flames normalised residence time transportequation for the numerical simulation of combustion with high-temperature air." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0002.
The present study is devoted to the modelling of turbulent reactive flows in cases where the temperature levels can lead to the self-ignition of the mixture. The proposed modelling strategy consists of treating separately the most important physical mechanisms : scalar mixing, flame propagation and self-ignition. Thus, simple methods derived from known models in non-premixed and premixed turbulent combustion(tabulation methods, presumed PDF) are used to represent the mixing mechanism of species and flame propagation. The most important development of this work concerns the method based on the use of a residence time to model the self-ignitionof the mixture. Since the direct comparison of the residence time with the self-ignition delay has no physical meaning as long as the composition and the temperature change before the self-ignition, a normalised residence time is introduced. This quantity can also be presented as the relative age of particles that age differently depending on the characteristics of the local mixture. The use of this normalised time also makes it possible to deal with the difficulty related to the boundary conditions of residence time. The proposed model is first used to simulate a non-premixed JHC(Jet-in-Hot-Coflow) turbulent flame in RANS with numerical computation softwareCode-Saturne(low Mach). This model is then validated by DNS calculations of 1D mixing layer subjected to self-ignition. Finally, preliminary numerical simulations of a recent experimental configuration available in the laboratory(Constant Volume Vessel) are carried out to evaluate the feasibility of extending the compressible LES model by using OpenFOAM
Muqbel, Mohammed Saleh. "Étude hydrochimique et isotopique de trois aquifères alluviaux (Oueds Tuban, Bana, Hadramoute) de la République démocratique populaire du Yémen (R. D. P. Y)." Paris 11, 1986. http://www.theses.fr/1986PA112072.
Chermaneanu, Raducu. "Représentation de la variabilité des propriétés mécaniques d’un CMO à l’échelle microscopique : Méthodes de construction des distributions statistiques." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14485/document.
Nowadays, composite materials are very widely used, notably in the domain of aeronautical structures, thanks to their numerous functional benefits. Their specific mechanical properties (properties/density) far superior to those of conventional materials, such as steel or aluminum and the realization of complex shapes, make these materials perfect candidates in many areas beyond aviation. However, these materials present at different observation scales sources of variability peculiar to each one. The manufacturing process and the properties of the elementary constituents are in fact the principal cause of these sources of variability. Three levels (or scales) of observation are usually considered regarding composite materials: the microscopic scale (fibers and matrix), the mesoscopic scale (ply) and finally the macroscopic scale (laminate material). The sources of variability propagate trough the scales and finally generate dispersed mechanical behaviors at the structure scale. Taking into consideration these sources is proved to be a relevant work by the designer, which in turn will allow him to calculate an indicator of the composite structure reliability that he is conceiving. To be able to do the latter work, it is necessary to transfer this variability at a lower computational cost from the microscopic level up to the structure scale. The construction of equivalent mechanical properties distributions according to the variability present at each scale is then essential. The objective of this research work was to build statistical distributions of the homogenized behavior of the material at the scale of fibers and matrix, according to the existing variability at this scale. Minimizing the computation time required for obtaining these distributions was another important objective. From a microscopic observation made on a section of a CMO, the morphological variability of the heterogeneous medium has been characterized and six different types of arrangements patterns of fibers grouped into cells have then been identified. Physically reasonable virtual cells have been developed and suggested, in order to build the equivalent behavior distribution by cell type, according to the relevant variables selected at this scale. Now, in order to minimize the computing time required for the creation of these distributions, an approach based on neural networks was proposed. This approach was used for a type 6 cell and for a number of 1000 FE calculations, in order to evaluate the quality of the approximation as well as the reduction of computation time. Hence, the reduction of the computation time was significant, at an approximate rate of 95 %
Paul, Maxence. "Étude des isotopes de l'osmium dans les eaux souterraines du Bangladesh et les sédiments himalayens : implications et rôle de l'érosion himalayenne sur le budget océanique de l'osmium." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL031N/document.
Using the Himalayan example, this study documents the systematics controlling the osmium composition of sediments during weathering processes, sedimentary transport and sediment deposition in tidal areas. The relationships observed between osmium concentrations and organic carbon contents in sediments of the Himalayan Kali Gandaki catchment underscore the role of black shales from the TSS (mostly unradiogenic) and LH (highly radiogenic) Himalayan units, despite their limited geographic distribution. However, the highly radiogenic composition displayed by Ganges sediments is not coupled to an enrichment in 187Os in these sediments, which on average are comparable to that of typical continental crust. Instead, the Ganges radiogenic signature results from an impoverishment in non-radiogenic osmium, reflecting a strong dilution by erosion products of crystalline rocks of the HHC unit. Moreover, based on the study of rivers in the tidal zone, we document the complex behavior of osmium at the salt/fresh water transition, potentially involving exchange between sediments and dissolved osmium. Analytical development performed concurrently with the sediment studies allowed the first measurements of groundwater osmium compositions. Groundwaters of Bengal plain aquifers have osmium contents significantly higher than those previously documented for river water or seawater. If this result can be generalized to other aquifers a global osmium groundwater flux to the ocean of about 170 kg per year could be expected. This contribution is significant and would require a reevaluation of both the osmium marine budget and the residence time of osmium in the ocean. This result could partially reconcile the diverging marine Os residence times estimated from mass balance and from glacial-interglacial variations in the 187Os/188Os marine record
Viet, Dang Nguyen. "Renormalisation de la théorie quantique des champs en espace-temps courbes: une approche causale." Phd thesis, Université Paris-Diderot - Paris VII, 2013. http://tel.archives-ouvertes.fr/tel-00918759.
Flecher, Cédric. "Conception d’un générateur de temps : développements méthodologiques pour des distributions asymétriques multivariées, application à l’étude de la sensibilité des cultures à la variabilité du climat et à ses modifications." Montpellier SupAgro, 2009. http://www.theses.fr/2009NSAM0039.
Bucaille, Philippe. "Etude expérimentale et modelisation B. E. M. Des phénomènes de couplage galvanique dans les cas d'une évolution des distributions du potentiel et du courant avec le temps et avec la freéuence." Dijon, 1997. http://www.theses.fr/1997DIJOS078.
Bourgin, Dominique. "Réactions de fusion entre ions lourds par effet tunnel quantique : le cas des collisions entre calcium et nickel." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE023/document.
Heavy-ion fusion-evaporation and nucleon transfer reactions at energies close to the Coulomb barrier play an essential role in the study of nuclear structure and reaction dynamics. In the framework of this PhD thesis, two fusion-evaporation and nucleon transfer experiments have been performed at the Laboratori Nazionali di Legnaro in Italy : 40Ca+58Ni and 40Ca+64Ni. In a first experiment, fusion cross sections for 40Ca+58,64Ni have been measured from above to below the Coulomb barrier and have been interpreted by means of coupled-channels and Time-Dependent Hartree-Fock (TDHF) calculations. The results show the importance of the one-phonon octupole excitation in the 40Ca nucleus and the one-phonon quadrupole excitations in the 58Ni and 64Ni nuclei, as well as the importance of the nucleon transfer channels in the neutron-rich system 40Ca+64Ni. In a complementary experiment, nucleon transfer probabilities for 40Ca+58,64Ni have been measured in the same energy region as the previous experiment and have been interpreted by performing TDHF+BCS calculations. The results confirm the importance of nucleon transfer channels in 40Ca+64Ni. A simultaneous description of the nucleon transfer probabilities and the fusion cross sections has been performed for both reactions, using a coupled-channels approach
Omer, Harold. "Modèles de déformation de processus stochastiques généralisés : application à l'estimation des non-stationnarités dans les signaux audio." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4723/document.
This manuscript deals with the modeling and estimation of certain non-stationarities in audio signals. We are particularly interested in a sound class models which we call dynamic*timbre in which a stationary signal, associated with the physical phenomenon causing the sound, is deformed over time by a linear unitary operator, called deformation operator, associated with the temporal evolution of the characteristics of this physical phenomenon.Audio signals are modeled as generalized Gaussian processes. We give first a set of mathematical tools that extend some classical notions used in signal processing in case of generalized stochastic processes.We then introduce the two deformations operators studied in this manuscript. The frequency modulation operator is the multiplication operator by a complex-valued function of unit module and the time-warping operator is the unit version of the composition operator by a bijective function.When these operators act on generalized stationary processes, deformed process are non-stationary generalized process which locally have stationarity properties and deformation operators can be approximated by translation operators in the time-frequency plans and time-scale.We give accurate versions of these approximations, as well as bounds for the corresponding approximation errors.Based on these approximations, we develop an approximated maximum likelihood estimator of the warping and modulation functions. The proposed algorithm is tested and validated on synthetic signals. Its application to natural sounds confirm the validity of the timbre*dynamic model in this context
Saari, Hanna-Kaisa. "Dynamique saisonnière des transferts particulaires dans les systèmes fluviaux-estuariens : application des radioisotopes à courtes périodes : 234 Th, 7 Be et 210 Pb." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13701/document.
The main objective of this study was to develop short-lived radioisotopes (234Th, 7Be and 210Pb) as tracers of particle transport in the Garonne-Dordogne-Gironde watershed. Firstly, the possibility to use 234Th/238U pair to study particle residence time in the Gironde fluvial-estuarine system was tested. The results show that dissolved 238U should be greater than 5 mBq l-1 to permit this application in fluvial systems. Secondly, the two years monitoring of natural radioisotopes, 234Th, 7Be and 210Pb, and artificial radioisotopes, 137Cs and 131I, in the Garonne and Lot rivers and in the Gironde Estuary, had allowed to observe the dynamic of particle transport, linked to the river flow. Based on this database, preliminary particle residence times and percentages of the new and old sediments were estimated. In the Lot and Garonne rivers, the particle retention ranges between 2-89 days during low and mean river discharges. The percentage of the new sediments is average 25 %, which indicates that the old resuspended sediments are dominated the suspended particulate matters (SPM). In the Gironde estuary, the particle residence time is mainly controlled by river discharge. The particle residence time during low river discharge is about 400 days. When the river discharge is increasing, the freshwaters are predominant in the estuary, the maximum turbidity zone (TMZ) is dispersed and the old sediments transported toward the ocean. During this period the particle residence time is only few months
Ghennioui, Hicham. "Séparation aveugle de mélanges linéaires convolutifs de sources corrélées." Phd thesis, Toulon, 2008. https://theses.hal.science/tel-00325910/fr/.
In this thesis, we study the problem of the blind separation of over-determined linear convolutive real or complex mixtures of deterministic or random, statistically independent or correlated, stationary, cyclo-stationary or non-stationary and real or complex sources. We have developed approaches that combine the new (non-unitary) joint (block) diagonalization to two novel detectors of particular points to build the matrices set to be joint (block) diagonalized. The main avantages of the proposed approaches are that they are more direct since they do not require a pre-whitening stage any more and that they can be used with correlated signals. Concerning the joint lock-diagonalization algorithms, we have proposed four joint block-diagonalization algoritms. The first algorithm is iterative and based on an algebraic optimization scheme. The three other ones are based on gradient approaches. The first one relies upon a gradient approach, but the matrix gradient is approximated, whereas the two other ones are based on an exact calculus (one is based on the gradient approach, the other is based on the relative gradient approach). The optimal step size versions of these three algorithms is provided to accelerate their convergence. It means that the step size is computed algebraically at each iteration as the rooting of a 3rd-degree polynomial. The main advantage of the proposed algorithms is that they are more general (the real, positive definite or hermitian assumptions about the matrices belonging to the considered set are no more necessary and the found joint block diagonalizer can be either a unitary or a non-unitary matrix). They can also be applied to solve the joint diagonalization problem
Ghennioui, Hicham. "Séparation aveugle de mélanges linéaires convolutifs de sources corrélées." Phd thesis, Université du Sud Toulon Var, 2008. http://tel.archives-ouvertes.fr/tel-00325910.
Dib, Rihab. "Compétition intra- et interspécifique chez deux parasitoïdes sympatriques : résolution des conflits et conséquences sur les stratégies d'exploitation des hôtes." Thesis, Tours, 2012. http://www.theses.fr/2012TOUR4025/document.
When two species exploit the same ecological niche, interspecific competition may lead to the exclusion of one of them. For the two species to co-exist, resource exploitation strategies developed by both species must somehow counter-balance each other. Eupelmus vuilleti and Dinarmus basalis are two solitary parasitoid species exploiting the same hosts, larvae and pupae of Callosobruchus maculatus. When confronted to already parasitized hosts (i.e. exploitative competition), Eupelmus vuilleti seems to be dominant and potentially able to exclude D. basalis. Here, we aim at understanding how E. vuilleti and D. basalis can coexist when in sympatry. More particularly, we investigate the behavioral strategies adopted by females of both species when exploiting the resource (i.e. host) in presence of a competitor female (conspecific or interspecific) (i.e. interference competition). Our study reveals that in presence of a competitor female, E. vuilleti and D. basalis females display agonistic behaviors and the contest resolution is mainly influenced by the value that contestants place on the resource. Finally, under interspecific direct competition, D. basalis females tend to outcompete E. vuilleti females: they are more aggressive. In contrast, E. vuilleti females adopt a waiting strategy, waiting for the opponent female’s departure to multiparasitize hosts after committing an ovicide. Thus, both species seem to show counterbalancing strategies which could promote their coexistence in nature and granaries
Tian, Yang. "Une contribution à l'observation et à l'estimation des systèmes linéaires." Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00590376.
Robert, Marianne. "Le comportement des thons tropicaux autour des objets flottants: de l'étude des comportements individuels et collectifs à l'étude du piège écologique." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209681.
Pour mener à bien ce travail, nous avons dans le premier chapitre caractérisé le comportement individuel de thons dans un réseau de DCP ancrés. L’analyse de données de marquage acoustique de 96 thons albacores (Thunnus albacares) (30-96 cm) à Hawaii montre que les thons présentent une plasticité comportementale forte face aux DCP qu’ils rencontrent mais également que le temps de résidence sous les DCP diminue avec la taille des individus. Afin de quantifier l’impact de l’augmentation de la densité de DCP il est essentiel de comprendre les mécanismes et les facteurs qui influencent les temps de résidences sous les DCP. Dans le second chapitre, des expériences de choix binaires suggèrent un rôle de la biomasse agrégée dans la formation, la maintenance et la dispersion des agrégations que forment les thons sous les objets flottants. La quantification de la dynamique des arrivées et des départs des poissons aux DCP permettra de valider les hypothèses que nous proposons concernant les mécanismes sociaux sous-jacents d’une part et d’autre part de tester l’influence de la qualité de l’environnement et de la densité de DCP sur les temps de résidences individuels et la distribution spatiale des populations. Dans le troisième chapitre, la comparaison de facteurs de condition de listaos (Katsuwonus pelamis) matures capturés en bancs libres et sous objets flottants dans une zone naturellement riche en objets flottants, et relativement peu impactée par le déploiement de DCP (Le Canal du Mozambique), nous a permis d’établir un point de référence essentiel pour estimer les effets des perturbations actuelles. Plus généralement, les résultats obtenus dans les différents chapitres tendent à conforter l’hypothèse d’un rôle social et non trophique des objets flottants dans l’écologie de thonidés. Les résultats obtenus durant cette thèse amènent à poser un regard nouveau sur l’hypothèse du piège écologique.
Notre travail s’est principalement intéressé à un modèle biologique de choix, les thons tropicaux. Cependant le cadre théorique des questions abordées, les outils d’observations et les méthodes d’analyses développées sont assez génériques pour être appliqués aux autres espèces rencontrées sous les objets flottants. Cette recherche s’intègre plus généralement dans les problématiques visant à mieux comprendre les stratégies comportementales et la distribution des populations dans des environnements multi-sites.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
Alban, Conto Maria-Carolina. "Private Income Transfers and Development : three Applied Essays on Latin America." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEH006/document.
For decades, economists have been interested in studying why and how agents support eachothers, giving a special place to the analysis of private income transfers. Recent applicationsinclude very diverse topics such as: the analysis of capital accumulation, social cohesion andsolidarity, market insurance and interest rates, risk-coping strategies against negative shocksand government policies.The present dissertation analyzes how inter-household transfer decisions, international remittancesand intra-household transfers contribute to shape five fundamental aspects of development:(i) social interactions, (ii) market and household work, (iii) spending patterns, (iv)nutrition and (v) health.Three research questions are addressed using applied data from Colombia, Ecuador and Peru,and multiple econometric techniques. First, is there a relationship between inter-householdtransfer dynamics and distance between donors and receivers? Second, do remittances asymmetricallyshape labor supply responses depending on people’s characteristics? Third, dointra-household transfers influence spending patterns, nutrition and health outcomes?Results suggest that private income transfers play a key re-distributive role, shaping agents’living standards and improving individual and social well-being. In contexts of economic deprivation,where social safety nets are scarce, informality is at stake, institutions are highlyfragmented and the public sector is weak, money and in-kind help from other households orindividuals constitute crucial livelihood strategies to get through the economic world. Thus,enhancing our understanding of this dimension of social behaviors is a must
Gonçalves, Paulo. "Représentations Temps-Fréquence et Temps-Echelle Bilinéaires: Synthèse et Contributions." Phd thesis, 1993. http://tel.archives-ouvertes.fr/tel-00572335.
Felx, Amélie. "Soutiens et contraintes de la relation d'aide reliés aux occupations : perceptions de résidants et du responsable d'une résidence d'accueil en santé mentale." Thèse, 2005. http://hdl.handle.net/1866/17635.
Pelletier, David. "Prévalence, déterminants et dynamique des arrangements de temps parental postséparation chez les enfants québécois nés à la fin des années 1990." Thèse, 2016. http://hdl.handle.net/1866/19529.
As more children are exposed to the separation of their parents, many of them have to share their time between the homes and the supervision of their mother and father. Whether this reality is referred to as “custody”, “residence” or “parenting time”, it greatly complicates the description and measurement of the family structures in which children evolve. In this context, the thesis has two main objectives. The first is to clarify the historical evolution of the various legal and sociological concepts involved and to show how the terminological confusion surrounding child custody raises problems when trying to measure children’s living arrangements. In particular, I try to determine the prevalence of egalitarian dual residence by critically assessing the various data sources available in Quebec and Canada. In the end, because of the shortcomings of these various sources and their sometimes divergent results, it is virtually impossible to answer the question: “How many children live in shared physical custody (or dual residence) ?” The second objective, which comprises most of the thesis, aims to illustrate the dynamic nature of parenting-time arrangements, an element often overlooked in the scientific literature. With data from the first thirteen waves of the Quebec Longitudinal Study of Child Development (QLSCD) (n = 2120), I distinguish four postseparation parenting-time arrangements: 1) mother residence (with little or no father-child contact); 2) mother residence (with regular father-child contact); 3) dual residence; 4) father residence. By ordering the information available at different time points for each child, I was able to reconstruct complete parenting-time trajectories. The analyzes carried out on these trajectories are reported in two articles. In the first article, I look at family characteristics related to the establishment of specific arrangements at separation and at the duration of this arrangement. For instance, I show that the share of parenting time assumed by fathers following separation is positively associated with parents’ education level, mothers’ full-time employment and father’s feeling of parental enjoyment. The article also shows that initial arrangements are not all as durable as each other. Although the factors associated with this duration are difficult to identify, the parents’ level of education appears to be play an important role. In the last article, I build multistate life tables in order to summarize parenting-time trajectories from the perspective of an average child. I try to determine, inter alia, how much time children spend in each of the four arrangements defined earlier and what sociodemographic factors are associated with this distribution of time. I show that time spent in dual residence by an average child is low, but that it increases with the education level of both parents. Dual residence is, however, a central component of postseparation fatherhood. Despite great fluidity in parenting-time trajectories, arrangements established at separation remain good predictors of the subsequent parenting experience. Children initially in dual residence, for instance, seldom lose contact with their father during the first five years following separation even if many of them eventually end up living mainly with their mother.
Ioana, Cornel. "Caratérisation des signaux non-stationnaires à composantes temps-fréquence non-linéaires." Habilitation à diriger des recherches, 2012. http://tel.archives-ouvertes.fr/tel-00985501.
Engmann, Sonja. "Redundancy gain : manifestations, causes and predictions." Thèse, 2009. http://hdl.handle.net/1866/3449.
Response times in a visual object recognition task decrease significantly if targets can be distinguished by two redundant attributes. Redundancy gain for two attributes is a common finding, but redundancy gain from three attributes has been found only for stimuli from three different modalities (tactile, auditory, and visual). This study extends those results by showing that redundancy gain from three attributes within the visual modality is possible. It also provides a more detailed investigation of the characteristics of redundancy gain. Apart from a decrease in response times for redundant targets, these include a decrease in minimal response times and an increase in symmetry of the response time distribution. This study further presents evidence that neither race models nor coactivation models can account for all characteristics of redundancy gain. In this context, we discuss the problem of calculating an upper limit for the performance of race models for triple redundant targets, and introduce a new method of evaluating triple redundancy gain based on performance for double redundant targets. In order to explain the results from this study, the cascade race model is introduced. The cascade race model consists of several input channels, which are triggered by a cascade of activations before satisfying a single decision criterion, and is able to provide a unifying approach to previous research on the causes of redundancy gain. The analysis of the characteristics of response time distributions, including their mean, symmetry, onset, and scale, is an essential tool in this study. It was therefore important to find an adequate statistical test capable of reflecting differences in all these characteristics. We discuss the problem and importance of analysing response times without data loss, as well as the inadequacy of common methods of analysis such as the pooling of response times across participants (e.g. Vincentizing) in the present context. We present tests of distributions as an alternative method for comparing distributions, response time distributions in particular, the most common of these being the Kolmogorov-Smirnoff test. We also introduce a test yet unknown in psychology: the two-sample Anderson-Darling test of goodness of fit. We compare both tests, presenting conclusive evidence that the Anderson-Darling test is more accurate and powerful: when comparing two distributions that vary (1) in onset only, (2) in scale only, (3) in symmetry only, or (4) that have the same mean and standard deviation but differ on the tail ends only, the Anderson-Darling test proves to detect differences better than the Kolmogorov-Smirnoff test. Finally, the Anderson-Darling test has a type I error rate corresponding to alpha whereas the Kolmogorov-Smirnoff test is overly conservative. Consequently, the Anderson- Darling test requires less data than the Kolmogorov-Smirnoff test to reach sufficient statistical power.
Khouider, Boualem. "Modélisation asymptotique pour la simulation aux grandes échelles de la combustion turbulente prémélangée." Thèse, 2002. http://hdl.handle.net/1866/6740.
Robert, Félix-Antoine. "La compétition et l’exploitation optimale des ressources chez les parasitoïdes." Thèse, 2015. http://hdl.handle.net/1866/13484.
Female parasitoids must adjust their behavior in response to different environmental factors when foraging for hosts. One of the most important factors they must cope with is the presence of competitors in their environment. The objective of this study is to measure the effects competition has on the foraging strategies of non-aggressive parasitoids. We used the species Trichogramma pintoi and T. minutum (Hymenoptera: Trichogrammatidae), two egg parasitoids of lepidoteran species. We measured patch residence times, patch-leaving mechanisms and progeny sex allocation of females foraging alone, and of females foraging under direct or indirect, intra- or interspecific competition. Trichogramma pintoi females favoured a general strategy entirely based on the perceived quality of the patch, whereas T. minutum females favoured a strategy that was adapted to the type of competition (direct or indirect) and to the nature of the competitors (intra- or interspecific) they were subjected to, with no regards for the quality of the patch. The distinction between these two strategies brings forth interesting research opportunities regarding the effects of competition at the landscape level, and should be of interest for biological control practitioners wishing to increase the efficacy of biological control programs and of commercial mass rearings.