The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Anna Wahlin - One of the best experts on this subject based on the ideXlab platform.
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influence of the coriolis force on the velocity structure of gravity currents in straight submarine channel systems
Journal of Geophysical Research, 2010Co-Authors: Remo Cossu, Mathew G Wells, Anna WahlinAbstract:[1] Large-scale turbidity currents in submarine channels often show a significant asymmetry in the heights of their levee banks. In the Northern Hemisphere, there are many observations of the right-hand channel levee being noticeably higher than the left-hand levee, a phenomenon that is usually attributed to the effect of Coriolis forces upon turbidity currents. This article presents results from an Analog Model that documents the influence of Coriolis forces on the dynamics of gravity currents flowing in straight submarine channels. The observations of the transverse velocity structure, downstream velocity, and interface slope show good agreement with a theory that incorporates Ekman boundary layer dynamics. Coriolis forces will be important for most large-scale turbidity currents and need to be explicitly Modeled when the Rossby number of these flows (defined as Ro = ∣U/Wf∣, where U is the mean downstream velocity, W is the channel width, and f is the Coriolis parameter defined as f = 2Ω sin(θ), with Ω being the Earth's rotation rate and θ being the latitude) is less than order 1. When Ro ≪ 1, the flow is substantially slower than a nonrotating flow with the same density contrast. The secondary flow field consists of frictionally induced Ekman transports across the channel in the benthic and interfacial boundary layers and a return flow in the interior. The cross-channel velocities are of the order of 10% of the along-channel velocities. The sediment transport associated with such transverse flow patterns should influence the evolution of submarine channel levee systems.
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influence of the coriolis force on the velocity structure of gravity currents in straight submarine channel systems
Journal of Geophysical Research, 2010Co-Authors: Remo Cossu, Mathew G Wells, Anna WahlinAbstract:[1] Large-scale turbidity currents in submarine channels often show a significant asymmetry in the heights of their levee banks. In the Northern Hemisphere, there are many observations of the right-hand channel levee being noticeably higher than the left-hand levee, a phenomenon that is usually attributed to the effect of Coriolis forces upon turbidity currents. This article presents results from an Analog Model that documents the influence of Coriolis forces on the dynamics of gravity currents flowing in straight submarine channels. The observations of the transverse velocity structure, downstream velocity, and interface slope show good agreement with a theory that incorporates Ekman boundary layer dynamics. Coriolis forces will be important for most large-scale turbidity currents and need to be explicitly Modeled when the Rossby number of these flows (defined as Ro = ∣U/Wf∣, where U is the mean downstream velocity, W is the channel width, and f is the Coriolis parameter defined as f = 2Ω sin(θ), with Ω being the Earth's rotation rate and θ being the latitude) is less than order 1. When Ro ≪ 1, the flow is substantially slower than a nonrotating flow with the same density contrast. The secondary flow field consists of frictionally induced Ekman transports across the channel in the benthic and interfacial boundary layers and a return flow in the interior. The cross-channel velocities are of the order of 10% of the along-channel velocities. The sediment transport associated with such transverse flow patterns should influence the evolution of submarine channel levee systems.
Armando Azuabustos - One of the best experts on this subject based on the ideXlab platform.
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aeolian transport of viable microbial life across the atacama desert chile implications for mars
Scientific Reports, 2019Co-Authors: Armando Azuabustos, Carlos Gonzalezsilva, Miguel Angel Fernandezmartinez, Cristian Arenasfajardo, Ricardo Fonseca, Javier F Martintorres, Maite Fernandezsampedro, Alberto G FairenAbstract:Here we inspect whether microbial life may disperse using dust transported by wind in the Atacama Desert in northern Chile, a well-known Mars Analog Model. By setting a simple experiment across the hyperarid core of the Atacama we found that a number of viable bacteria and fungi are in fact able to traverse the driest and most UV irradiated desert on Earth unscathed using wind-transported dust, particularly in the later afternoon hours. This finding suggests that microbial life on Mars, extant or past, may have similarly benefited from aeolian transport to move across the planet and find suitable habitats to thrive and evolve.
Patrick Segers - One of the best experts on this subject based on the ideXlab platform.
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multiscale Modeling of the blood circulation in the human liver using vascular corrosion casting and micro ct imaging techniques
Proceedings of the ASME 2011 Summer Bioengineering Conference, 2011Co-Authors: Charlotte Debbaut, Diethard Monbaliu, Christophe Casteleyn, Pieter Cornillie, Jacques Pirenne, Paul Simoens, Luc Van Hoorebeke, Patrick SegersAbstract:Numerical Models to analyze blood flow may be important for a better understanding of organ hemodynamics and (dys)function (e.g. in organ transplant research), and diagnostic techniques (e.g. contrast-enhanced MRI to characterize tumors). Existing Models of (liver) vascular trees are predominantly based on idealized Models using fractional calculus to describe bifurcating branching patterns. In contrast, we previously developed an electrical Analog Model of the human hepatic circulation, based on measured data of the macrocirculation and extrapolated data of the microcirculation [1]. Furthermore, the microcirculation is usually Modeled as a porous medium [2].Copyright © 2011 by ASME
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from vascular corrosion cast to electrical Analog Model for the study of human liver hemodynamics and perfusion
IEEE Transactions on Biomedical Engineering, 2011Co-Authors: Charlotte Debbaut, Diethard Monbaliu, Christophe Casteleyn, Pieter Cornillie, Denis Van Loo, Bert Masschaele, Jacques Pirenne, Paul Simoens, Luc Van Hoorebeke, Patrick SegersAbstract:Hypothermic machine perfusion (HMP) is experiencing a revival in organ preservation due to the limitations of static cold storage and the need for better preservation of expanded criteria donor organs. For livers, perfusion protocols are still poorly defined, and damage of sinusoidal endothelial cells and heterogeneous perfusion are concerns. In this study, an electrical Model of the human liver blood circulation is developed to enlighten internal pressure and flow distributions during HMP. Detailed vascular data on two human livers, obtained by combining vascular corrosion casting, micro-CT-imaging and image processing, were used to set up the electrical Model. Anatomical data could be measured up to 5-6 vessel generations in each tree and showed exponential trend lines, used to predict data for higher generations. Simulated flow and pressure were in accordance with literature data. The Model was able to simulate effects of pressure-driven HMP on liver hemodynamics and reproduced observations such as flow competition between the hepatic artery and portal vein. Our simulations further indicate that, from a pure biomechanical (shear stress) standpoint, HMP with low pressures should not result in organ damage, and that fluid viscosity has no effect on the shear stress experienced by the liver microcirculation in pressure-driven HMP.
Remo Cossu - One of the best experts on this subject based on the ideXlab platform.
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influence of the coriolis force on the velocity structure of gravity currents in straight submarine channel systems
Journal of Geophysical Research, 2010Co-Authors: Remo Cossu, Mathew G Wells, Anna WahlinAbstract:[1] Large-scale turbidity currents in submarine channels often show a significant asymmetry in the heights of their levee banks. In the Northern Hemisphere, there are many observations of the right-hand channel levee being noticeably higher than the left-hand levee, a phenomenon that is usually attributed to the effect of Coriolis forces upon turbidity currents. This article presents results from an Analog Model that documents the influence of Coriolis forces on the dynamics of gravity currents flowing in straight submarine channels. The observations of the transverse velocity structure, downstream velocity, and interface slope show good agreement with a theory that incorporates Ekman boundary layer dynamics. Coriolis forces will be important for most large-scale turbidity currents and need to be explicitly Modeled when the Rossby number of these flows (defined as Ro = ∣U/Wf∣, where U is the mean downstream velocity, W is the channel width, and f is the Coriolis parameter defined as f = 2Ω sin(θ), with Ω being the Earth's rotation rate and θ being the latitude) is less than order 1. When Ro ≪ 1, the flow is substantially slower than a nonrotating flow with the same density contrast. The secondary flow field consists of frictionally induced Ekman transports across the channel in the benthic and interfacial boundary layers and a return flow in the interior. The cross-channel velocities are of the order of 10% of the along-channel velocities. The sediment transport associated with such transverse flow patterns should influence the evolution of submarine channel levee systems.
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influence of the coriolis force on the velocity structure of gravity currents in straight submarine channel systems
Journal of Geophysical Research, 2010Co-Authors: Remo Cossu, Mathew G Wells, Anna WahlinAbstract:[1] Large-scale turbidity currents in submarine channels often show a significant asymmetry in the heights of their levee banks. In the Northern Hemisphere, there are many observations of the right-hand channel levee being noticeably higher than the left-hand levee, a phenomenon that is usually attributed to the effect of Coriolis forces upon turbidity currents. This article presents results from an Analog Model that documents the influence of Coriolis forces on the dynamics of gravity currents flowing in straight submarine channels. The observations of the transverse velocity structure, downstream velocity, and interface slope show good agreement with a theory that incorporates Ekman boundary layer dynamics. Coriolis forces will be important for most large-scale turbidity currents and need to be explicitly Modeled when the Rossby number of these flows (defined as Ro = ∣U/Wf∣, where U is the mean downstream velocity, W is the channel width, and f is the Coriolis parameter defined as f = 2Ω sin(θ), with Ω being the Earth's rotation rate and θ being the latitude) is less than order 1. When Ro ≪ 1, the flow is substantially slower than a nonrotating flow with the same density contrast. The secondary flow field consists of frictionally induced Ekman transports across the channel in the benthic and interfacial boundary layers and a return flow in the interior. The cross-channel velocities are of the order of 10% of the along-channel velocities. The sediment transport associated with such transverse flow patterns should influence the evolution of submarine channel levee systems.
Alberto G Fairen - One of the best experts on this subject based on the ideXlab platform.
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aeolian transport of viable microbial life across the atacama desert chile implications for mars
Scientific Reports, 2019Co-Authors: Armando Azuabustos, Carlos Gonzalezsilva, Miguel Angel Fernandezmartinez, Cristian Arenasfajardo, Ricardo Fonseca, Javier F Martintorres, Maite Fernandezsampedro, Alberto G FairenAbstract:Here we inspect whether microbial life may disperse using dust transported by wind in the Atacama Desert in northern Chile, a well-known Mars Analog Model. By setting a simple experiment across the hyperarid core of the Atacama we found that a number of viable bacteria and fungi are in fact able to traverse the driest and most UV irradiated desert on Earth unscathed using wind-transported dust, particularly in the later afternoon hours. This finding suggests that microbial life on Mars, extant or past, may have similarly benefited from aeolian transport to move across the planet and find suitable habitats to thrive and evolve.