scholarly journals Soil Particle Transport and Mixing Near a Hillslope Crest: 2. Cosmogenic Nuclide and Optically Stimulated Luminescence Tracers

2018 ◽  
Vol 123 (5) ◽  
pp. 1078-1093 ◽  
Author(s):  
David Jon Furbish ◽  
Joshua J. Roering ◽  
Amanda Keen‐Zebert ◽  
Peter Almond ◽  
Tyler H. Doane ◽  
...  
Keyword(s):  
Particle Transport ◽  
Optically Stimulated Luminescence ◽  
Soil Particle ◽  
Cosmogenic Nuclide ◽  
Transport And Mixing

scholarly journals Soil Particle Transport and Mixing Near a Hillslope Crest: 1. Particle Ages and Residence Times

2018 ◽  
Vol 123 (5) ◽  
pp. 1052-1077 ◽  
Author(s):  
David Jon Furbish ◽  
Joshua J. Roering ◽  
Peter Almond ◽  
Tyler H. Doane
Keyword(s):  
Particle Transport ◽  
Soil Particle ◽  
Residence Times ◽  
Transport And Mixing

scholarly journals Evidence from the Rio Bayo valley on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene Transition

2006 ◽  
Vol 65 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Neil F. Glasser ◽  
Stephan Harrison ◽  
Susan Ivy-Ochs ◽  
Geoffrey A.T. Duller ◽  
Peter W. Kubik
Keyword(s):  
Late Pleistocene ◽  
Climatic Conditions ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Age Dating ◽  
Outlet Glacier ◽  
Geomorphological Mapping ◽  
Cosmogenic Nuclide ◽  
The North ◽  
Exposure Age

AbstractThis paper presents data on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene transition using cosmogenic nuclide exposure age and optically stimulated luminescence dating. We describe geomorphological and geochronological evidence for glacier extent in one of the major valleys surrounding the North Patagonian Icefield, the Rio Bayo valley. Geomorphological mapping provides evidence for the existence of two types of former ice masses in this area: (i) a large outlet glacier of the North Patagonian Icefield, which occupied the main Rio Bayo valley, and (ii) a number of small glaciers that developed in cirques on the slopes of the mountains surrounding the valley. Cosmogenic nuclide exposure-age dating of two erratic boulders on the floor of the Rio Bayo valley indicate that the outlet glacier of the icefield withdrew from the Rio Bayo valley after 10,900 ± 1000 yr (the mean of two boulders dated to 11,400 ± 900 yr and 10,500 ± 800 yr). Single-grain optically stimulated luminescence (OSL) dating of an ice-contact landform constructed against this glacier indicates that this ice mass remained in the valley until at least 9700 ± 700 yr. The agreement between the two independent dating techniques (OSL and cosmogenic nuclide exposure age dating) increases our confidence in these age estimates. A date obtained from a boulder on a cirque moraine above the main valley indicates that glaciers advanced in cirques surrounding the icefield some time around 12,500 ± 900 yr. This evidence for an expanded North Patagonian Icefield between 10,900 ± 1000 yr and 9700 ± 700 yr implies cold climatic conditions dominated at this time.

Particle Interaction Forces Induce Soil Particle Transport during Rainfall

2013 ◽  
Vol 77 (5) ◽  
pp. 1563-1571 ◽  
Author(s):  
Song Li ◽  
Hang Li ◽  
Chen-Yang Xu ◽  
Xue-Ru Huang ◽  
De-Ti Xie ◽  
...  
Keyword(s):  
Particle Transport ◽  
Particle Interaction ◽  
Soil Particle ◽  
Interaction Forces

Raindrop-induced and wind-driven soil particle transport

CATENA ◽  
2002 ◽  
Vol 47 (3) ◽  
pp. 227-243 ◽  
Author(s):  
G Erpul ◽  
L.D Norton ◽  
D Gabriels
Keyword(s):  
Particle Transport ◽  
Soil Particle

Effects of strong ionic polarization in the soil electric field on soil particle transport during rainfall

2015 ◽  
Vol 66 (5) ◽  
pp. 921-929 ◽  
Author(s):  
S. Li ◽  
H. Li ◽  
F. N. Hu ◽  
X. R. Huang ◽  
D. T. Xie ◽  
...  
Keyword(s):  
Electric Field ◽  
Particle Transport ◽  
Soil Particle ◽  
Soil Electric Field ◽  
Ionic Polarization

scholarly journals The rarefied (non-continuum) conditions of tracer particle transport in soils, with implications for assessing the intensity and depth dependence of mixing from geochronology

2018 ◽  
Author(s):  
David Jon Furbish ◽  
Rina Schumer ◽  
Amanda Keen-Zebert
Keyword(s):  
Particle Transport ◽  
Tracer Particle ◽  
Planck Equation ◽  
Strong Mixing ◽  
Surface Erosion ◽  
Soil Thickness ◽  
Particle Mixing ◽  
Mixing Intensity ◽  
Mixing Behavior ◽  
Transport And Mixing

Abstract. We formulate tracer particle transport and mixing in soils due to disturbance driven particle motions in terms of the Fokker-Planck equation. The probabilistic basis of the formulation is suitable for rarefied particle conditions, and for parsing the mixing behavior of extensive and intensive properties belonging to the particles rather than to the bulk soil. The significance of the formulation is illustrated with the examples of vertical profiles of expected 10Be concentrations and particle OSL ages for the benchmark situation involving a one-dimensional mean upward soil motion with nominally steady surface erosion in the presence of either uniform or depth dependent particle mixing, and varying mixing intensity. The analysis, together with Eulerian-Lagrangian numerical simulations of tracer particle motions, highlight the significance of calculating ensemble expected values of extensive and intensive particle properties, including higher moments of particle OSL ages, rather than assuming de facto a continuum-like mixing behavior, with implications for field sampling and for describing the mixing behavior of other particle and soil properties. Profiles of expected 10Be concentrations and OSL ages systematically vary with mixing intensity as measured by a Peclet number involving the speed at which particles enter the soil, the soil thickness, and the particle diffusivity. Profiles associated with uniform mixing versus a linear decrease in mixing with depth are distinct for moderate mixing, but become similar with either weak mixing or strong mixing; uniform profiles do not necessarily imply uniform mixing.

scholarly journals The rarefied (non-continuum) conditions of tracer particle transport in soils, with implications for assessing the intensity and depth dependence of mixing from geochronology

2018 ◽  
Vol 6 (4) ◽  
pp. 1169-1202 ◽  
Author(s):  
David Jon Furbish ◽  
Rina Schumer ◽  
Amanda Keen-Zebert
Keyword(s):  
Particle Transport ◽  
Tracer Particle ◽  
Planck Equation ◽  
Strong Mixing ◽  
Surface Erosion ◽  
Soil Thickness ◽  
Particle Mixing ◽  
Mixing Intensity ◽  
Mixing Behavior ◽  
Transport And Mixing

Abstract. We formulate tracer particle transport and mixing in soils due to disturbance-driven particle motions in terms of the Fokker–Planck equation. The probabilistic basis of the formulation is suitable for rarefied particle conditions, and for parsing the mixing behavior of extensive and intensive properties belonging to the particles rather than to the bulk soil. The significance of the formulation is illustrated with the examples of vertical profiles of expected beryllium-10 (10Be) concentrations and optically stimulated luminescence (OSL) particle ages for the benchmark situation involving a one-dimensional mean upward soil motion with nominally steady surface erosion in the presence of either uniform or depth-dependent particle mixing, and varying mixing intensity. The analysis, together with Eulerian–Lagrangian numerical simulations of tracer particle motions, highlights the significance of calculating ensemble-expected values of extensive and intensive particle properties, including higher moments of particle OSL ages, rather than assuming de facto a continuum-like mixing behavior. The analysis and results offer guidance for field sampling and for describing the mixing behavior of other particle and soil properties. Profiles of expected 10Be concentrations and OSL ages systematically vary with mixing intensity as measured by a Péclet number involving the speed at which particles enter the soil, the soil thickness, and the particle diffusivity. Profiles associated with uniform mixing versus a linear decrease in mixing with depth are distinct for moderate mixing, but they become similar with either weak mixing or strong mixing; uniform profiles do not necessarily imply uniform mixing.

Flow and Particle Dispersion in a Pulmonary Alveolus—Part I: Velocity Measurements and Convective Particle Transport

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Sudhaker Chhabra ◽  
Ajay K. Prasad
Keyword(s):  
Particle Transport ◽  
Vector Fields ◽  
Wall Motion ◽  
Flow Patterns ◽  
Particle Dispersion ◽  
Alveolar Wall ◽  
Spherical Cap ◽  
Image Velocimetry ◽  
Transport And Mixing

The alveoli are the smallest units of the lung that participate in gas exchange. Although gas transport is governed primarily by diffusion due to the small length scales associated with the acinar region (∼500 μm), the transport and deposition of inhaled aerosol particles are influenced by convective airflow patterns. Therefore, understanding alveolar fluid flow and mixing is a necessary first step toward predicting aerosol transport and deposition in the human acinar region. In this study, flow patterns and particle transport have been measured using a simplified in-vitro alveolar model consisting of a single alveolus located on a bronchiole. The model comprises a transparent elastic 5/6 spherical cap (representing the alveolus) mounted over a circular hole on the side of a rigid circular tube (representing the bronchiole). The alveolus is capable of expanding and contracting in phase with the oscillatory flow through the tube. Realistic breathing conditions were achieved by exercising the model at physiologically relevant Reynolds and Womersley numbers. Particle image velocimetry was used to measure the resulting flow patterns in the alveolus. Data were acquired for five cases obtained as combinations of the alveolar-wall motion (nondeforming/oscillating) and the bronchiole flow (none/steady/oscillating). Detailed vector maps at discrete points within a given cycle revealed flow patterns, and transport and mixing of bronchiole fluid into the alveolar cavity. The time-dependent velocity vector fields were integrated over multiple cycles to estimate particle transport into the alveolar cavity and deposition on the alveolar wall. The key outcome of the study is that alveolar-wall motion enhances mixing between the bronchiole and the alveolar fluid. Particle transport and deposition into the alveolar cavity are maximized when the alveolar wall oscillates in tandem with the bronchiole fluid, which is the operating case in the human lung.

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