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parent f11e82a2ac51edab880561842c4118f33172b5d7
Author: Anders Damsgaard <anders@adamsgaard.dk>
Date: Thu, 16 Dec 2021 11:56:24 +0100
fix post
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| M | pages/013-neel.html | | | 80 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| M | pages/013-neel.txt | | | 83 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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+<p>Today, <a href="mailto:ineel@alumni.stanford.edu">Indraneel
+Kasmalkar</a> had his paper published in <a
+href="https://agupubs.onlinelibrary.wiley.com/journal/19422466">Journal of
+Geophysical Research: Earth Surface</a>. Congratulations Neel! He used
+my software <a href="https://src.adamsgaard.dk/sphere">sphere</a>, and
+sheared a granular assembledge with a non-trivial forcing in order to
+learn more about subglacial sediment behavior.</p>
+
+
+
+<h2>Abstract</h2>
+<blockquote>
+<b>Shear Variation at the Ice-Till Interface Changes the Spatial
+Distribution of Till Porosity and Meltwater Drainage</b>
+<br><br>
+Indraneel Kasmalkar(1), Anders Damsgaard(2), Liran Goren(3), Jenny Suckale(1,4,5)
+<br><br>
+1: Department of Computational and Mathematical Engineering, Stanford University, CA, USA
+<br>
+2: Department of Geoscience, Aarhus University, Denmark
+<br>
+3: Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
+<br>
+4: Department of Geophysics, Stanford University, CA, USA
+<br>
+5: Department of Civil and Environmental Engineering, Stanford University, CA, USA
+<br><br>
+Plain-language summary:<br>
+The ice at the base of certain glaciers moves over soft sediments
+that route meltwater through the pore spaces in between the sediment
+grains. The ice shears the sediment, but it is not clear if this slow
+shearing is capable of changing the structure or volume of the pore space,
+or the path of the meltwater that flows through the sediment. To study
+the relations between the shearing of the sediment and the changes in its
+pore space, we use computer simulations that portray the sediment as a
+collection of closely packed spherical grains, where the pores are filled
+with meltwater. To shear the simulated sediment, the grains at the top
+are pushed with fixed speeds in the horizontal direction. Despite the
+slow shear, which is generally thought of as having no effect on pore
+space, our results show that shearing changes the sizes of the pores
+in between the grains, where large pores are formed near the top of the
+sediment layer. If the grains at the top are pushed with uneven speeds,
+then the largest pores are formed in the areas where grain speeds vary
+the most. We show that the exchange of meltwater between neighboring
+pores is faster than the movement of the grains, indicating that the
+meltwater can adjust quickly to changing pore space.
+<br><br>
+Abstract:<br>
+Many subglacial environments consist of a fine-grained, deformable
+sediment bed, known as till, hosting an active hydrological system that
+routes meltwater. Observations show that the till undergoes substantial
+shear deformation as a result of the motion of the overlying ice. The
+deformation of the till, coupled with the dynamics of the hydrological
+system, is further affected by the substantial strain rate variability
+in subglacial conditions resulting from spatial heterogeneity at the
+bed. However, it is not clear if the relatively low magnitudes of strain
+rates affect the bed structure or its hydrology. We study how laterally
+varying shear along the ice-bed interface alters sediment porosity and
+affects the flux of meltwater through the pore spaces. We use a discrete
+element model consisting of a collection of spherical, elasto-frictional
+grains with water-saturated pore spaces to simulate the deformation
+of the granular bed. Our results show that a deforming granular layer
+exhibits substantial spatial variability in porosity in the pseudo-static
+shear regime, where shear strain rates are relatively low. In particular,
+laterally varying shear at the shearing interface creates a narrow zone
+of elevated porosity which has increased susceptibility to plastic
+failure. Despite the changes in porosity, our analysis suggests that
+the pore pressure equilibrates near-instantaneously relative to the
+deformation at critical state, inhibiting potential strain rate dependence
+of the deformation caused by bed hardening or weakening resulting from
+pore pressure changes. We relate shear variation to porosity evolution
+and drainage element formation in actively deforming subglacial tills.
+</blockquote>
+
+<h2>Links and references:</h2>
+<ul>
+ <li><a href="https://doi.org/10.1029/2021JF006460">Publication on journal webpage</a> (closed access)</li>
+ <li><a href="papers/Kasmalkar et al 2021 Shear variation at the ice-till interface changes the spatial distribution of till porosity and meltwater drainage.pdf">Preprint PDF</a>
+ <li><a href="https://src.adamsgaard.dk/sphere">Simulation software</a></li>
+</ul>
diff --git a/pages/013-neel.txt b/pages/013-neel.txt
@@ -0,0 +1,83 @@
+Today, [1]Indraneel Kasmalkar had his paper published in [2]Journal of
+Geophysical Research: Earth Surface. Congratulations Neel! He used my software
+[3]sphere, and sheared a granular assembledge with a non-trivial forcing in
+order to learn more about subglacial sediment behavior.
+
+Abstract
+
+ Shear Variation at the Ice-Till Interface Changes the Spatial Distribution
+ of Till Porosity and Meltwater Drainage
+
+ Indraneel Kasmalkar(1), Anders Damsgaard(2), Liran Goren(3), Jenny Suckale
+ (1,4,5)
+
+ 1: Department of Computational and Mathematical Engineering, Stanford
+ University, CA, USA
+ 2: Department of Geoscience, Aarhus University, Denmark
+ 3: Department of Earth and Environmental Sciences, Ben-Gurion University of
+ the Negev, Beer-Sheva, Israel
+ 4: Department of Geophysics, Stanford University, CA, USA
+ 5: Department of Civil and Environmental Engineering, Stanford University,
+ CA, USA
+
+ Plain-language summary:
+ The ice at the base of certain glaciers moves over soft sediments that
+ route meltwater through the pore spaces in between the sediment grains. The
+ ice shears the sediment, but it is not clear if this slow shearing is
+ capable of changing the structure or volume of the pore space, or the path
+ of the meltwater that flows through the sediment. To study the relations
+ between the shearing of the sediment and the changes in its pore space, we
+ use computer simulations that portray the sediment as a collection of
+ closely packed spherical grains, where the pores are filled with meltwater.
+ To shear the simulated sediment, the grains at the top are pushed with
+ fixed speeds in the horizontal direction. Despite the slow shear, which is
+ generally thought of as having no effect on pore space, our results show
+ that shearing changes the sizes of the pores in between the grains, where
+ large pores are formed near the top of the sediment layer. If the grains at
+ the top are pushed with uneven speeds, then the largest pores are formed in
+ the areas where grain speeds vary the most. We show that the exchange of
+ meltwater between neighboring pores is faster than the movement of the
+ grains, indicating that the meltwater can adjust quickly to changing pore
+ space.
+
+ Abstract:
+ Many subglacial environments consist of a fine-grained, deformable sediment
+ bed, known as till, hosting an active hydrological system that routes
+ meltwater. Observations show that the till undergoes substantial shear
+ deformation as a result of the motion of the overlying ice. The deformation
+ of the till, coupled with the dynamics of the hydrological system, is
+ further affected by the substantial strain rate variability in subglacial
+ conditions resulting from spatial heterogeneity at the bed. However, it is
+ not clear if the relatively low magnitudes of strain rates affect the bed
+ structure or its hydrology. We study how laterally varying shear along the
+ ice-bed interface alters sediment porosity and affects the flux of
+ meltwater through the pore spaces. We use a discrete element model
+ consisting of a collection of spherical, elasto-frictional grains with
+ water-saturated pore spaces to simulate the deformation of the granular
+ bed. Our results show that a deforming granular layer exhibits substantial
+ spatial variability in porosity in the pseudo-static shear regime, where
+ shear strain rates are relatively low. In particular, laterally varying
+ shear at the shearing interface creates a narrow zone of elevated porosity
+ which has increased susceptibility to plastic failure. Despite the changes
+ in porosity, our analysis suggests that the pore pressure equilibrates
+ near-instantaneously relative to the deformation at critical state,
+ inhibiting potential strain rate dependence of the deformation caused by
+ bed hardening or weakening resulting from pore pressure changes. We relate
+ shear variation to porosity evolution and drainage element formation in
+ actively deforming subglacial tills.
+
+Links and references:
+
+ • [4]Publication on journal webpage (closed access)
+ • [5]Preprint PDF
+ • [6]Simulation software
+
+
+References:
+
+[1] mailto:ineel@alumni.stanford.edu
+[2] https://agupubs.onlinelibrary.wiley.com/journal/19422466
+[3] https://src.adamsgaard.dk/sphere
+[4] https://doi.org/10.1029/2021JF006460
+[5] https://adamsgaard.dk/papers/Kasmalkar%20et%20al%202021%20Shear%20variation%20at%20the%20ice-till%20interface%20changes%20the%20spatial%20distribution%20of%20till%20porosity%20and%20meltwater%20drainage.pdf
+[6] https://src.adamsgaard.dk/sphere
