Teses / dissertações sobre o tema "Quantification de phases minérales"
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Gontier, Adrien. "Quantification de l'altération dans les sols par les déséquilibres radioactifs : approche sur sol total et phases minérales séparées". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAH011/document.
Texto completo da fonteThe aim of the present study was to evaluate weathering and soil formation rates using U-Th disequilibria in bulk soil or separated minerals. The specific objectives of this work were to evaluate the use of U-Th chronometric tools 1) regarding the impact of a land cover change and the bedrock characteristics 2) in selected secondary mineral phases and 3) in primary minerals. On the Breuil-Chenue (Morvan) site, no vegetation effect neither a grain size effect was observed on the U-Th series in the deepest soil layers (< 40cm). The low soil production rate (1-2 mm/ka) is therefore more affected by regional geomorphology than by the underlying bedrock texture. In the second part of this work, based on a thorough evaluation of different technics, a procedure was retained to extract Fe-oxides without chemical fractionation. Finally, the analysis of biotites hand-picked from one of the studied soil profile showed that U- series disequilibria allow to independently determinate the field-weathering-rate of minerals
Simonnet, Titouan. "Apprentissage et réseaux de neurones en tomographie par diffraction de rayons X. Application à l'identification minéralogique". Electronic Thesis or Diss., Orléans, 2024. http://www.theses.fr/2024ORLE1033.
Texto completo da fonteUnderstanding the chemical and mechanical behavior of compacted materials (e.g. soil, subsoil, engineered materials) requires a quantitative description of the material's structure, and in particular the nature of the various mineralogical phases and their spatial relationships. Natural materials, however, are composed of numerous small-sized minerals, frequently mixed on a small scale. Recent advances in synchrotron-based X-ray diffraction tomography (to be distinguished from phase contrast tomography) now make it possible to obtain tomographic volumes with nanometer-sized voxels, with a XRD pattern for each of these voxels (where phase contrast only gives a gray level). On the other hand, the sheer volume of data (typically on the order of 100~000 XRD patterns per sample slice), combined with the large number of phases present, makes quantitative processing virtually impossible without appropriate numerical codes. This thesis aims to fill this gap, using neural network approaches to identify and quantify minerals in a material. Training such models requires the construction of large-scale learning bases, which cannot be made up of experimental data alone.Algorithms capable of synthesizing XRD patterns to generate these bases have therefore been developed.The originality of this work also concerned the inference of proportions using neural networks. To meet this new and complex task, adapted loss functions were designed.The potential of neural networks was tested on data of increasing complexity: (i) from XRD patterns calculated from crystallographic information, (ii) using experimental powder XRD patterns measured in the laboratory, (iii) on data obtained by X-ray tomography. Different neural network architectures were also tested. While a convolutional neural network seemed to provide interesting results, the particular structure of the diffraction signal (which is not translation invariant) led to the use of models such as Transformers. The approach adopted in this thesis has demonstrated its ability to quantify mineral phases in a solid. For more complex data, such as tomography, improvements have been proposed
Mędala, Marta. "Etudes des interactions entre les phases minérales constituant le ciment Portland et des solutions salines concentrées". Dijon, 2005. http://www.theses.fr/2005DIJOS061.
Texto completo da fonteNicoleau, Luc. "Interactions physico-chimiques entre le latex et les phases minérales constituant le ciment au cours de l'hydratation". Dijon, 2004. http://www.theses.fr/2004DIJOS047.
Texto completo da fonteHazarabedian, Maria Sofia. "Deleterious Intergranular Phases in Nickel Alloy 725: Detection, Identification and Quantification". Thesis, Curtin University, 2021. http://hdl.handle.net/20.500.11937/88096.
Texto completo da fontePéru, Laurence. "Caractérisations physico-chimiques des phases minérales de calcifications ectopiques : application à la transformation biologique de phosphates de calcium". Châtenay-Malabry, Ecole centrale de Paris, 1993. http://www.theses.fr/1993ECAP0325.
Texto completo da fontePierron, Olivier. "Interactions eau-fer-argilite : rôle des paramètres liquide/roche, fer/argilite, température sur la nature des phases minérales". Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10146/document.
Texto completo da fonteThe interactions between the iron metal and the argillite from the Callovo-Oxfordian formation chosen as host for the disposal of the radioactive wastes, was experimentally studied. The role of the key parameters of the transformations (iron / clay, and liquid / rock ratios) was studied at 90°C, and, to accelerate reaction kinetics, at 150°C and 300°C. Mixed layered illite-smectite and illites are dissolved and replaced by new clay phases. TEM analyses show that Fe-serpentines (7 Å phases, group of the berthierine) predominates in run products at 90°C, tri-octaedral Fe-rich smectites at 150°C, and chlorites and probably smectite chlorite mixed layered at 300°C. Whatever the temperature, the illite and I/S replacement is not complete and trun products are always accompanied by sodi-calcic residual and/ or newly formed smectites. In comparison with the iron-smectite (bentonite) system, the differences concern the reaction kinetics which are much faster in the case of the argillite, and the instability of the quartz which, as the illite, contributes to release the silicium necessary for the formation of iron silicates. The observed process find analogies with the hydrothermal changes described in natural hydrothermal alterations and Fe-Mg metasomatism
Bohic, Sylvain. "Apport de la spectroscopie et de la microspectroscopie infrarouge à transformée de Fourier à l'étude des phases minérales des tissus calcifiés et des biomatériaux". Nantes, 1998. http://www.theses.fr/1998NANT030D.
Texto completo da fonteBrazier, Jean-Michel. "Rôle des phases minérales des sols en tant que réservoirs de nutriments : approche expérimentale (abiotique), en milieu naturel et multi-isotopique (isotopes stables Ca-Sr)". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAH005/document.
Texto completo da fonteThis PhD thesis examined the mechanisms of storage and release, from and elementary and isotopically point of view, of calcium (Ca) and strontium (Sr) onto or into mineral phases commonly encountered within soils (primary minerals, clay minerals, oxy-hydroxides, pedogenic carbonate). A robust δ88Sr measurements method had to be developed in the laboratory and validated by the measurement of international reference materials, mostly never measured in the literature. The results of this work show that Ca adsorption onto phyllosilicate minerals generates a quantifiable isotopic fractionation by preferential uptake of the light isotope (40Ca) under our experimental conditions when the minerals have a significant structural charge and specific surface area and/or an interlayer space open to hydrated cations adsorption. A study on rhizoliths in natural environment has also highlighted that the combination of Ca and Sr isotopes allows an effective tracing of sources and mechanisms in the problematic related to the storage of these two elements within soils
Birman, Jessie. "Quantification et propagation d'incertitude dans les phases amont de projets de conception d'avions : de l'optimisation déterministe à l'optimisation sous contraintes probabilistes". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2269/.
Texto completo da fonteConceptual aircraft sizing is the first step in the development project of a passenger transport aircraft. Classically, in this phase, a lot of aircraft configurations are compared after having been globally sized thanks to a deterministic, multidisciplinary and constrained optimisation problem. The purpose is to determine the main characteristics of the airplane according to a set of Top Level Requirements. At preliminary stage, designers have to deal with limited knowledge and high uncertainty when solving this problem. Managing that uncertainty is a major issue: assessing its impact on the design in the early stage allows to save time and cost. This PhD thesis introduces a new methodology to solve the aircraft design optimisation affected by uncertainty. First of all, the main source of uncertainty involved at this stage is identified as predictive model uncertainty, which is part of epistemic uncertainty. This uncertainty is quantified within a probabilistic framework. For that purpose, based on the Beta distribution, we create a new generic distribution function able to assume a wide range of distribution shapes: it is called Beta-Mystique distribution. Second of all, we realise uncertainty propagation studies with Monte Carlo and moment propagation methods, in order to analyse the robustness of aircraft configuration according to a set of uncertainties. Finally, a chance constrained optimisation is solved to produce a robust aircraft configuration. Two strategies are considered: the use of Surrogate models to approximate the probabilities and the resolution of the optimisation problem thanks to the moment propagation method
Anwander, Alfred. "Segmentation d'images couleur par un opérateur gradient vectoriel multiéchelle et contour actif : application à la quantification des phases minéralogiques du clinker de cimen". Lyon, INSA, 2001. http://theses.insa-lyon.fr/publication/2001ISAL0062/these.pdf.
Texto completo da fonteThe objective of this thesis is the quantification of cement clinker phases by analysis of color images acquired with an optical microscope. The segmentation of the crystals is approached in a double way adapted to industrial constraints. The first introduces an orignal computation of the color gradient for images acquired with a standard mono-CCD color camera. These multispectral images have the particularity of a reduced resolution of color components compared to that of luminance. The adaptation of a multiscale approach and weighting of the components are integrated in a new multiscale color gradient (MCG) operator. Comparative studies with classical techniques in the domain of edge detection, show the contribution of the MCG. The second original model concerns image segmentation by deformable contours of “balloon” type. Our model stabilizes the deformation by normalizing the contour length at each iteration. This allows big deformations of the contour without re-sampling of the contour, which is necessary in the classical approach. The algorithm is faster, more robust and allows an initial contour which is far from the final contour. The software developed in partnership with the company “Lafarge Ciments” integrates the different color image processing techniques. Pre-processing of the images, segmentation by edge detection using the MCG of the microscopic color images and edge closing. The homogeneous regions segmentation in this way are classified using color and texture parameters. The system computes a quantification of the three clinker phases and a statistical analysis of the crystal dimensions. It replaces long and tiring manual measurements and allows a high quality production by more frequent measurements at the exit of the cement kiln
Anwander, Alfred Neyran Bruno Baskurt Atilla. "Segmentation d'images couleur par un opérateur gradient vectoriel multiéchelle et contour actif application à la quantification des phases minéralogiques du clinker de ciment /". Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=anwander.
Texto completo da fonteMorais, David. "Les déterminants des phases épidémiques précoces de la septoriose du blé (Zymoseptoria tritici) : quantité, efficacité et origine de l'inoculum primaire". Electronic Thesis or Diss., Paris, AgroParisTech, 2015. http://www.theses.fr/2015AGPT0021.
Texto completo da fonteFungal foliar diseases are a major constraint to cereal production systems. They constitute relevant models to elucidate how an epidemic begins, which is a recurrent question in plant disease epidemiology. In this thesis three of the main components of the early stages of the epidemics of septoria tritici blotch, a wheat disease caused by Zymoseptoria tritici, were studied: the quantity, the efficiency and the origin of primary inoculum. The study focused on epidemics occurring over the 2011-2013 cultural seasons in two wheat plots located close to each other in Grignon (France). The first plot, characterized by the absence of debris, was exposed to distant sources of primary inoculum, while the second plot, grown in wheat for several years, had a large amount of contaminated debris acting as a local source of primary inoculum. In the first part of the thesis, ascospore trapping using a volumetric spore trap combined with DNA quantification by qPCR allowed to quantify the inoculums present in the air above the wheat plots during the early stages of the epidemics. The limits of detection and quantification were determined, discussed and used to estimate small amounts of ascospores. Neither the local presence of contaminated debris nor the quantity of inoculum above the plots was correlated with the earliness of the epidemics. In the second part, the pathogenicity of Z. tritici ascospores and pycnidiospores was estimated on adult plants. The latent period following infections by ascospores was 60 degree-days longer than following infection by pycnidiospores. In the third part of the thesis, which aimed to identify the source of primary inoculum, two strategies were developed. The first strategy investigated changes in the genetic structure of different subpopulations collected from both wheat plots over a period of three years using neutral markers (SSR). No structure was identified, but slight differentiations in some subpopulations, consistent with the epidemiological context (nature of the reproduction cycle from which they derived, epidemic period, disease intensity) were highlighted. These results, however, did not allow to determine the origin of the primary inoculum because no difference between resident (local) and immigrant (distant) subpopulations, or a genetic discontinuity between subpopulations from the end (season n) and the beginning of epidemics (season n + 1), were identified. The second strategy compared the aggressiveness profile (sporulation capacity and latent period) of a Z. tritici population collected at the beginning of an epidemic in the monoculture wheat plot and of a resident population (ascospores ejected from debris present in the plot) and to an immigrant population (leaf lesions caused by ascospores of distant origin). The profile of the tested population, closer to that of the resident population, suggested that the epidemic was mainly initiated by primary inoculum of local origin. This case study showed that a quantitative management (reduction) of the primary inoculum would be probably inefficient, while its qualitative management, taking into account the differential adaptation of pathogen populations to their hosts, deserves to be taken into account in crop protection strategies (alternating wheat cultivars in time). Finally, the definition of the beginning and the end of an epidemic was discussed, depending if we consider an annual scale (absence of the host as a beginning or end criterion) or a multiannual scale (pathogen pressure discontinuity as the beginning or end criterion, regardless of the absence of the host)
Petus, Caroline. "Qualité des eaux côtières du Sud du Golfe de Gascogne par télédétection spatiale : méthodologie de détermination et de quantification de substances particulaires et dissoutes". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13943/document.
Texto completo da fonteThe southern Bay of Biscay coastal waters are under the direct influence of the freshwater plume from the Adour estuary. The river outflow leads to a strong variability in the concentration of mineral suspended matters (MSM in mg l-1), chlorophyll-a (Chla, mg, m-3) and colored dissolved organic matters (CDOM in mg l-1) contained in coastal waters. By changing the transparency of the water and carrying nutrients and bacteria, they may affect biological productivity and have a significant impact on human health. Our study aims to develop empirical algorithms and test the efficiency of MODIS-Aqua imagery to map particulate and dissolved substances contained in coastal waters under the influence of the Adour plume. In this aim, two oceanographic missions were carried out to measure simultaneously the MSM, turbidity, Chla and CDOM and the remote sensing reflectance of water. Two empirical operational algorithms for quantification of suspended mineral matters and turbidity have been developed. An automated processing of atmospherically-corrected MODIS-Aqua-250m product (MYD09GQ product) was performed. This operating system has been used to map the concentrations of suspended sediment content in the plume at 246 days between 2006 and 2009. Thus, the first study at large spatial and temporal scale of the Adour plume dynamics has been achieved. Finally, several algorithms have been proposed in order to quantify the concentrations of chlorophyll-a in the southern Bay of Biscay. These empirical relations must be tested on new in-situ measurements to clarify their validity limits. Our study shows the contribution of the MODIS satellite imagery to monitor the Adour plume. In future, an effective monitoring system of Aquitaine coastal water quality could be considered
Hétier, Mickaël. "Analyse et quantification des comportements des conducteurs automobiles lors des phases de pré-crash : Contribution au développement d'un modèle de détection des postures de conduite en temps réel". Valenciennes, 2009. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/06d45dbc-30f5-4321-8a44-db264fe3d947.
Texto completo da fonteStandardisation of crash-tests implies that the occupants are protected and seated with a predetermined position. In addition, standardisation does not take into account individual characteristics, real position and anticipatory reactions during a crash. Thus, it is essential to study the incidences of human beings' morphologies before a crash. It is indeed very important to study the effects of real, standardised and atypical postures in relation with the active protection systems. In fact, during the phase called pre-crash, the driver anticipates and tries to avoid the crash with a swerving movement. During the crash, these kinematics and dynamical modifications increase the injuries severity of the car occupant. Thus, a new concept of automobile safety was developed by the C2S, a LAMIH's research team, and the INRETS-LBMC laboratory. This concept consists of deducing, in real time, the anthropometry, and the driver's reactions and postures, with basic sensors, in order to adapt driver's protection systems at the crash time. For example, this system will modify, in function of driver's characteristics, the volume of airbags, the seat adjustments, or the pretentionners' performances. This doctoral thesis contributed to create this new concept and to develop the methodology. This methodology will allow to detect, in real time, the driver's behaviour and position, from results obtained with driving simulator tests
OUGUERRAM, LAHCEN. "Nouvelle approche pour l'exploitation du signal f. I. D. Obtenu en r. M. N. Du domaine du temps : application a la mise en evidence et a la quantification de phases intermediaires dans la matiere grasse laitiere". Nantes, 1997. http://www.theses.fr/1997NANT2071.
Texto completo da fontePhuphachong, Thanyanan. "Magneto-spectroscopy of Dirac matter : graphene and topological insulators". Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066170.
Texto completo da fonteThis thesis reports on the study under magnetic field of the electronic properties of relativistic-like Dirac fermions in two Dirac systems: graphene and topological insulators. Their analogies with high-energy physics and their potential applications have attracted great attention for fundamental research in condensed matter physics. The carriers in these two materials obey a Dirac Hamiltonian and the energy dispersion is analogous to that of the relativistic particles. The particle rest mass is related to the band gap of the Dirac material, with the Fermi velocity replacing the speed of light. Graphene has been considered as a “role model”, among quantum solids, that allows us to study the relativistic behavior of massless Dirac fermions satisfying a linear dispersion. When a Dirac system possesses a nonzero gap, we have massive Dirac fermions. Massless and massive Dirac fermions were studied in high-mobility multilayer epitaxial graphene and in topological crystalline insulators Pb1-xSnxSe and Pb1-xSnxTe. The latter system is a new class of topological materials where the bulk states are insulating but the surface states are conducting. This particular aspect results from the inversion of the lowest conduction and highest valence bulk bands having different parities, leading to a topological phase transition. Infrared magneto-spectroscopy is an ideal technique to probe these zero-gap or narrow gap materials since it provides quantitative information about the bulk parameters via the Landau quantization of the electron states. In particular, the topological phase transition can be characterized by a direct measurement of the topological index
Phuphachong, Thanyanan. "Magneto-spectroscopy of Dirac matter : graphene and topological insulators". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066170/document.
Texto completo da fonteThis thesis reports on the study under magnetic field of the electronic properties of relativistic-like Dirac fermions in two Dirac systems: graphene and topological insulators. Their analogies with high-energy physics and their potential applications have attracted great attention for fundamental research in condensed matter physics. The carriers in these two materials obey a Dirac Hamiltonian and the energy dispersion is analogous to that of the relativistic particles. The particle rest mass is related to the band gap of the Dirac material, with the Fermi velocity replacing the speed of light. Graphene has been considered as a “role model”, among quantum solids, that allows us to study the relativistic behavior of massless Dirac fermions satisfying a linear dispersion. When a Dirac system possesses a nonzero gap, we have massive Dirac fermions. Massless and massive Dirac fermions were studied in high-mobility multilayer epitaxial graphene and in topological crystalline insulators Pb1-xSnxSe and Pb1-xSnxTe. The latter system is a new class of topological materials where the bulk states are insulating but the surface states are conducting. This particular aspect results from the inversion of the lowest conduction and highest valence bulk bands having different parities, leading to a topological phase transition. Infrared magneto-spectroscopy is an ideal technique to probe these zero-gap or narrow gap materials since it provides quantitative information about the bulk parameters via the Landau quantization of the electron states. In particular, the topological phase transition can be characterized by a direct measurement of the topological index
Varet, Guillaume. "Caractérisation des bruts lourds en présence de solvant". Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3007/document.
Texto completo da fonteDue to increasing demand for fuel, in particular for developed countries, and the limited nature of reserves, petroleum industry is, and will, growing concerned by the heavy and and extra-heavy oil processing. The non-conventional properties of these oils (due to a high asphaltene composition) require specific engineering solutions during the different steps of their processing. These crudes, mainly localized in Canada and Venezuela, are characterized by their strong viscosity, from 1 up to 55 Pa.s, which makes their transport to earth surface impossible. The development of new technological solutions is based on a better knowledge of the thermophysical properties and the colloidal behavior of these products. The methods of experimental characterization and modelling used for the conventional crudes are unsuited for both heavy and extra heavy crudes. To date, characterization PVT of heavy crudes is the subject of numerous studies. The properties to be determined are balances of phase and thermophysical properties of the equilibrium cycles. In this context, the main objectives of this thesis are not only the development of experimental methods and models suitable for heavy crudes, but also the recovery processes envisaged for these crudes (cold production, VAPEX process, SAGD process, etc…)