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1. Proietti, Arnaud. Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure.

Degree: Docteur es, Sciences de l'Univers, de l'Environnement et de l'Espace, 2016, Université Toulouse III – Paul Sabatier

Cette thèse s'intéresse à la rhéologie de deux des principaux minéraux du manteau supérieur terrestre : l'olivine et l'orthopyroxène. Dans un premier temps, des agrégats polycristallins à grains fins (entre 100 nm et 5 &m) d'olivine et de pyroxène ont été synthétisés par frittage flash (Spark Plasma Sintering) ainsi que par frittage sous vide. Ces échantillons ont ensuite été déformés à des pressions comprises entre 2 et 6 GPa dans des presses de typeD-DIA, installées sur des lignes de lumière des synchrotrons NSLS et ESRF afin d'avoir une mesure in situ de la contrainte différentielle et de la déformation. L'effet de la pression sur la plasticité basse température de l'olivine a été étudié à température ambiante (ligne ID06 du synchrotron ESRF, Grenoble). Les mécanismes de déformation à haute température de l'olivine et de l'orthopyroxène ont également été étudiés, pour des températures comprises entre 900 et 1200°C (ligne X17B2 du synchrotron NSLS, New York). Les données mécaniques ainsi que l'analyse des microstructures par EBSD, suggèrent une déformation par fluage diffusion. Des lois rhéologiques incluant l'effet de la pression, de la température, de la contrainte et de la taille de grain ont été déterminées pour les deux minéraux. A ces conditions, le pyroxène est moins visqueux que l'olivine. Enfin, des échantillons biphasés, avec un rapport volumique Ol/Px de 70/30 et 80/20, ont été déformés. La contrainte différentielle calculée dans chacune des deux phases suggère la contribution d'un second mécanisme de déformation en plus du fluage diffusion, en accord avec les observations microstructurales.

This thesis presents our work on the rheology of two of the main minerals of the upper mantle: olivine and orthopyroxene. First, fined-grained polycrystalline aggregates (with grain sizes between 100 nm and 5 &m) of olivine and pyroxene were synthesized by Spark Plasma Sintering (SPS) and vacuumsintering. The samples were then deformed at pressures between 2 and 6 GPa in D-DIA presses installed on synchrotrons X-ray beamlines at NSLS and ESRF so thatmeasurements of the differential stress and strain could be obtained in situ. The influence of pressure on low-temperature plasticity of olivine was studied at room temperature (ID06 beamline, ESRF synchrotron, Grenoble). High-temperature deformation mechanisms of olivine and orthopyroxene were also studied between 900 and 1200°C (X17B2 beamline, NSLS synchrotron, New York). Mechanical results and microstructural analysis by EBSD suggest a deformation by diffusion creep. Rheological laws including the effect of pressure, temperature, differential stress and grain size were determined for each mineral. Under these conditions, orthopyroxene appears less viscous than olivine. Finally, two-phase aggregates (Ol/Px volume ration of 80/20 and 70/30) were also deformed. Differential stress, estimated in each phase, indicates the contribution of a second deformation mechanism, in agreement with microstructural observations.

Advisors/Committee Members: Bystricky, Misha (thesis director), Béjina, Frédéric (thesis director).

Subjects/Keywords: Olivine; Orthopyroxène; Déformation; Haute pression; D-DIA; Fluage diffusion; Systèmes polyphasés; Frittage; EBSD; Olivine; Orthopyroxene; Deformation; High pressure; D-DIA; Diffusion creep; Polyphase aggregates; Sintering; EBSD

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Proietti, A. (2016). Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure. (Doctoral Dissertation). Université Toulouse III – Paul Sabatier. Retrieved from http://www.theses.fr/2016TOU30171

Chicago Manual of Style (16th Edition):

Proietti, Arnaud. “Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure.” 2016. Doctoral Dissertation, Université Toulouse III – Paul Sabatier. Accessed April 25, 2019. http://www.theses.fr/2016TOU30171.

MLA Handbook (7th Edition):

Proietti, Arnaud. “Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure.” 2016. Web. 25 Apr 2019.

Vancouver:

Proietti A. Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure. [Internet] [Doctoral dissertation]. Université Toulouse III – Paul Sabatier; 2016. [cited 2019 Apr 25]. Available from: http://www.theses.fr/2016TOU30171.

Council of Science Editors:

Proietti A. Rhéologie d'agrégats olivine-orthopyroxène sous haute pression : Rheology of olivine-orthopyroxene aggregates at high pressure. [Doctoral Dissertation]. Université Toulouse III – Paul Sabatier; 2016. Available from: http://www.theses.fr/2016TOU30171


EPFL

2. Reymond, Philippe. Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree.

Degree: 2011, EPFL

Blood flow in the arterial circulation induces hemodynamic forces that play an important role in various forms of vascular diseases. Temporal variation of the wall shear stress seems to play a significant role in atherogenesis and plaque stability. Flow induced wall shear stress has been linked to growth and possibly rupture of the aneurysm wall. Hemodynamic forces are patient-specific and difficult to assess in the clinic. At present, there is no in vivo measurement technique that enables measurement of hemodynamic forces to the degree of precision needed. However, when imaging modalities used frequently in clinical routine re-create high-definition, patient geometric quantification of the blood vessel, they can be employed as a base for creating predictive hemodynamic models. Which in the case of understanding healthy vs. pathologic blood flow within the cerebral or systemic circulation, renders this an interesting approach. First, we developed a "generic 1D" distributed model of the human arterial tree including the primary systemic arteries and coupled this to a heart model. The fluid mechanics equations were solved numerically to obtain pressure and flow throughout the arterial tree. A nonlinear viscoelastic constitutive law for the arterial wall was considered while distal vessels were terminated with a three-element Windkessel model. The coronary arteries were modeled assuming a systolic flow impediment proportional to ventricular varying elastance. The model predictions were validated with noninvasive measurements of pressure and flow performed in young volunteers. Flow in the large arteries was visualized with magnetic resonance imaging, cerebral flow detected with ultrasound Doppler and blood pressure measured with applanation tonometry. Model predictions at different arterial locations compared well to measured flow and pressure waves at the same anatomical points. Thus, the generic 1D model reflected the flow and pressure measurements of the "average subject" of our volunteer population. Following the same approach as the generic 1D model, we built and validated a patient-specific model. In this case, geometric data, flow and pressure measurements were obtained for one person. The model predicted pressure and flow waveforms in good agreement with the in-vivo measurements with regards to wave shape and features. Comparison with a generic 1-D model has shown that the patient-specific model better predicted pressure and flow at specific arterial sites. Overall, the patient-specific 1-D model was able to predict pressure and flow waveforms in the main systemic circulation, whereas this was not always the case for a generic 1-D model. The inherent underestimation of energy losses of the 1-D wave propagation model, due to bifurcations,… Advisors/Committee Members: Stergiopulos, Nikolaos.

Subjects/Keywords: wave propagation; hemodynamic; cerebral circulation; 1-D model; noninvasive measurements techniques; PC-MRI; MRI; MRA; Doppler; heart model; ventricular-vascular coupling; viscoelasticity; vascular imaging; CFD; FSI; Non-Newtonian blood; blood flow simulation; medical images reconstruction; propagation d'ondes de pression; hémodynamique; circulation cérébrale; modèle 1-D; techniques de mesure non invasives; IRM à contraste de phase; Doppler; modèle cardiaque; couplage ventriculaire artériel; viscoélasticité; CFD; FSI; sang Non-Newtonien; reconstruction images médicale

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Reymond, P. (2011). Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/164023

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Reymond, Philippe. “Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree.” 2011. Thesis, EPFL. Accessed April 25, 2019. http://infoscience.epfl.ch/record/164023.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Reymond, Philippe. “Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree.” 2011. Web. 25 Apr 2019.

Vancouver:

Reymond P. Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree. [Internet] [Thesis]. EPFL; 2011. [cited 2019 Apr 25]. Available from: http://infoscience.epfl.ch/record/164023.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Reymond P. Pressure and Flow Wave Propagation in Patient-Specific Models of the Arterial Tree. [Thesis]. EPFL; 2011. Available from: http://infoscience.epfl.ch/record/164023

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.