Search

Your search keyword '"Knapp, Yannick"' showing total 19 results
Start Over Author "Knapp, Yannick"
19 results on '"Knapp, Yannick"'

8. Measurement of Cyclic Flows in Trachea Using PIV and Numerical simulation

Author

Bělka Miloslav, Elcner Jakub, Jedelský Jan, Boiron Olivier, Knapp Yannick, and Bailly Lucie

Subjects
Physics, QC1-999
Abstract

Inhalation of pharmaceutical aerosols is a convenient way to treat lung or even systemic diseases. For effective treatment it is very important to understand air flow characteristics within respiratory airways and determine deposition hot spots. In this paper the air flow in trachea was investigated by numerical simulations. To validate these results we carried out particle image velocimetry experiments and compared resulting velocity fields. Simplified geometry of respiratory airways from oral cavity to 4th generation of branching was employed. Air flow characteristics were analysed during sinusoidal breathing pattern for light activity conditions (period 4 s and tidal volume 1 l). The observed flow fields indicated that the flow in trachea is turbulent during the sinusoidal flow except phases of flow turnarounds. The flow was skewed to front side of the trachea during inspiration and had twin-peak profile during expiration because of the mixing from daughter branches. The methods were compared and good agreement was found. This validation of CFD simulation can result into its further usage in respiratory airflow studies.

Published
2015
Full Text
View/download PDF

10. RED BLOOD CELL GHOSTS FLOW IN MICRO CHANNEL

Author

Knapp, Yannick, Deplano, Valérie, EA4278 Laboratoire de Pharm-Ecologie Cardiovasculaire (LaPEC), Avignon Université (AU), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), D. Mitton, Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), and Deplano, Valerie

Subjects
[PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Abstract

International audience; Optical characterization of high hematocrit whole blood flows in small to medium size vessels are of particular interest in many patho-physiological conditions. However, such characterizations remain challenging because of the optical properties of blood. Blood is a complex multiphasic fluid and its optical and rheological properties are governed by interactions between red blood cells (RBC) and plasma. In particular the transmission characteristics of such a suspension is ruled by the combined effect of absorption from some molecules and scattering from the cells. These combined effects make it globally difficult to image RBC at high hematocrit in depth larger than a few 10th of micrometers limiting therefore the studies to small size vessels or to wall regions . Major rheological and fluid mechanical behaviors are therefore not accessible with traditional laboratory instrumentation. As an example, the blunting of the velocity profile is a known effect in physiological high hematocrit flow conditions. Such a deviation from the traditionally accepted Poiseuille theory has a major consequence on the local flow conditions (shear rate/stress) and can hardly be observed because of the aforementioned limitations. To overcome such problems, transparent suspensions can be prepared by using RBC ghosts (i.e. hemoglobin free RBC) [1]. By such a technique one can obtain a transparent high hematocrit mixture that can be imaged over large depth of flow (Figure 1, right) in which high precision microscopic particle image velocimetry flow field measurements (microPIV) can be performed. To demonstrate this capacity and to have a close insight in the flow of a blood mimicking fluid in vessels larger than previously reported in the literature are the goals of this work.

Published
2016

11. Measurement of Cyclic Flows in Trachea Using PIV and Numerical simulation

Author

Bělka, Miloslav, Elcner, Jakub, Jedelský, Jan, Boiron, Olivier, Knapp, Yannick, Bailly, Lucie, Bělka, Miloslav, Elcner, Jakub, Jedelský, Jan, Boiron, Olivier, Knapp, Yannick, and Bailly, Lucie

Abstract

Inhalation of pharmaceutical aerosols is a convenient way to treat lung or even systemic diseases. For effective treatment it is very important to understand air flow characteristics within respiratory airways and determine deposition hot spots. In this paper the air flow in trachea was investigated by numerical simulations. To validate these results we carried out particle image velocimetry experiments and compared resulting velocity fields. Simplified geometry of respiratory airways from oral cavity to 4th generation of branching was employed. Air flow characteristics were analysed during sinusoidal breathing pattern for light activity conditions (period 4 s and tidal volume 1 l). The observed flow fields indicated that the flow in trachea is turbulent during the sinusoidal flow except phases of flow turnarounds. The flow was skewed to front side of the trachea during inspiration and had twin-peak profile during expiration because of the mixing from daughter branches. The methods were compared and good agreement was found. This validation of CFD simulation can result into its further usage in respiratory airflow studies., Inhalace farmaceutických aerosolů je pohodlný způsob, kterým se lečí dýchací obtíže. Pro efektivní léčbu je potřeba přivést aerosol na předem určené místo a k tomu je nutné dobře porozumět proudění v dýchacích cestách. V tomto článku byl studováno proudění v průdušnici za pomoci PIV a CFD. Byla snaha validovat výsledky simulací pomocí experimentu. Proudění se měřilo v zjednodušeném modelu plic během sinusoidového dechového režimu. Byla nalezena dobrá shoda, což povedeno k dalšímu použití CFD při studiu proudění v plicích.

Published
2015

12. Flow dynamics characterisation of a novel perfusiontype bioreactor for bone tissue engineering

Author

Knapp, Yannick, Deplano, Valérie, Bertrand, Eric, Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Taylor & Francis, Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), and Deplano, Valerie

Subjects
[SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

13. Local mass transport and mechanical stimuli generated with perfused porous scaffold

Author

Oddou, Christian, Dantan, Philippe, Knapp, Yannick, Deplano, Valérie, Laboratoire de Modélisation et Simulation Multi Echelle (MSME), Université Paris-Est Marne-la-Vallée (UPEM)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Matière et Systèmes Complexes (MSC (UMR_7057)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Matière et Systèmes Complexes (MSC), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Deplano, Valerie, and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Paris-Est Marne-la-Vallée (UPEM)

Subjects
[SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Abstract

proceeding p 29

Published
2010

14. Écoulement dans un micro modèle de milieu poreux

Author

Knapp, Yannick, Oddou, Christian, Deplano, Valérie, Unité mixte de recherche Climat Sol et Environnement (UMR CSE 1114), Institut National de la Recherche Agronomique (INRA)-Avignon Université (AU), LMP, Faculté des Sciences & Technologie, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), GDR2760, Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), and Deplano, Valerie

Subjects
[SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Published
2009

15. Emballage-Environnement : bilan et perspectives

Author

Tissandié, Charles, Knapp, Yannick, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), and Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, éco-conception, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2008

16. Mesures µPIV dans un modèle de milieu poreux

Author

Knapp, Yannick, Bertrand, Éric, Stefanini, Jean, Association Française de Mécanique, and Service irevues, irevues

Subjects
PIV, milieu poreux, [PHYS.MECA]Physics [physics]/Mechanics [physics], [PHYS.MECA] Physics [physics]/Mechanics [physics], microfluidique
Abstract

Colloque avec actes et comité de lecture. Internationale.; International audience; L'étude présentée porte sur la mesure des champs de vitesses dans un milieu poreux et en particulier dans les pores de tels milieux. Le milieu poreux utilisé possède des caractéristiques géométriques et dimensionnelles proches de celles observées dans le cas d'un sol. Les champs de vitesses sont déterminés à l'aide d'une méthode de micro vélocimétrie par image de particules (µPIV ) adaptée aux spécificités du modèle utilisé. Les résultats obtenus sont comparés à des observations réalisées sur un modèle similaire dans le cadre d'une étude portant sur la détermination des capacités de filtrage de ce type de milieu au regard de la taille des particules (phénomène de ségrégation). Les deux types de résultats sont en bon accord et les hypothèses formulées pour expliquer le filtrage partiel sont confirmées par la présente étude.

Published
2007

17. Anévrisme de l'Aorte Abdominale et compliance

Author

Deplano, Valérie, Knapp, Yannick, Bertrand, Eric, Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de recherche Climat Sol et Environnement (UMR CSE 1114), Institut National de la Recherche Agronomique (INRA)-Avignon Université (AU), Deplano, Valerie, and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)

Subjects
[SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Published
2007

19. Shear rate gradients promote a bi-phasic thrombus formation on weak adhesive proteins, such as fibrinogen in a VWF-dependent manner.

Author

Receveur N, Nechipurenko D, Knapp Y, Yakusheva A, Maurer E, Denis CV, Lanza F, Panteleev M, Gachet C, and Mangin PH

Subjects
Adhesives, Blood Platelets, Fibrinogen, Humans, Platelet Adhesiveness, Platelet Aggregation, Thrombosis, von Willebrand Factor
Abstract

Blood flow profoundly varies throughout the vascular tree due to its pulsatile nature and to the complex vessel geometry. While thrombus formation has been extensively studied in vitro under steady flow, and in vivo under normal blood flow conditions, the impact of complex hemodynamics such as flow acceleration found in stenosed arteries has gained increased appreciation. We investigated the effect of flow acceleration, characterized by shear rate gradients, on the function of platelets adhering to fibrinogen, a plasma protein which plays a key role in hemostais and thrombosis. While we confirmed that under steady flow, fibrinogen only supports single platelet adhesion, we observed that under shear rate gradients, this surface becomes highly thrombogenic, supporting efficient platelet aggregation leading to occlusive thrombus formation. This shear rate gradient-driven thrombosis is biphasic with an initial step of slow platelet recruitment supported by direct plasma VWF adsorption to immobilized fibrinogen and followed by a second phase of explosive thrombosis initiated by VWF fiber formation on platelet monolayers. In vivo experiments confirmed that shear rate gradients accelerate thrombosis in a VWF-dependent manner. Together, this study characterizes a process of plasma VWF-dependent accelerated thrombosis on immobilized fibrinogen in the presence of shear rate gradients.

Published
2020
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results