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Events
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Apr16
EVENT DETAILS
lessTitle: Frustrated Assemblies: Describing Matter from Within
Speaker: Efi Efrati, Weizmann Institute of Science
Abstract: Frustrated assemblies are comprised of ill-fitting building blocks whose favored local relative arrangement cannot be globally realized. In fact, most self assembled structures contain some degree of frustration. In some cases, the frustration is locally resolved and leads to little or no structural consequence, while in other cases it dominates the assembly's size, shape, and response properties. In this talk, I will present different manifestations of geometric frustration as they naturally arise in molecular crystals, liquid crystals, spin systems, and nanoparticle assemblies. To theoretically study these assemblies we resort to an intrinsic approach in which matter is described only through local properties available to an observer residing within the material. The frustration is then quantified by the geometric compatibility conditions whose structure allows us to classify the frustration and predict the assembly's behavior without explicitly solving for the ground state of the system.
Zoom: https://northwestern.zoom.us/j/96136137709
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TIME Tuesday, April 16, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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Apr23
EVENT DETAILS
lessTitle: Contrail Climate Impacts: Modeling and Mitigation Strategies
Speaker: Tom Dean, Breakthrough Energy
Abstract: Aviation accounts for approximately 3.5% of global anthropogenic climate forcing. Of this, less than half is attributed to the CO2 output from fuel combustion. Nearly half of the total climate impact of aviation can be attributed to contrail cirrus – cirrus clouds that have been seeded by the exhaust plumes of the aircraft – though with considerable uncertainty. Given that only around 2-3% of all flights were are likely responsible for 80% of the global annual contrail climate forcing, a potential contrail mitigation strategy could involve re-routing this subset of flights to minimize the formation of strongly warming contrails. Studies have shown that such strategies would require as little as 0.2% additional fuel burn. Implementing such a strategy requires an accurate ability to forecast contrail impacts, which in turn requires accurate modeling of microphysical atmospheric processes at flight levels. In this talk we will give an overview of contrail modeling and describe the grid-based Contrail Cirrus Prediction model (CoCiP), whose output is designed to be input as a layer in flight planning tools.
Zoom: https://northwestern.zoom.us/j/95168994177
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TIME Tuesday, April 23, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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Apr30
EVENT DETAILS
lessTitle: Shocks and Caps in Drop Electrohydrodynamics
Speaker: Ehud Yariv, Technion - Israel Institute of Technology
Abstract: The problem of electrohydrodynamic drop deformation is well understood in the case where the external electric field is weak. In one of his many celebrated papers (Proc. R. Soc. A, 291 1425 159-166, 1966), G. I. Taylor worked out a complete theory in this limit, including analytical expressions for the electrohydrodynamic flow engendered within and outside of the drop by the electric field acting on its own induced interfacial charge, and a simple function of the permittivity, conductivity and viscosity drop-to-background ratios discriminating between prolate or oblate deformation. In this talk, we will employ numerical and asymptotic tools to explore the effects of interfacial-charge convection, which were neglected by Taylor but become important at strong electric fields. In particular, we will analyze (in 2D, for simplicity) how Taylor’s fore-aft symmetric solution evolves as the electrical Reynolds number is increased from zero to arbitrarily large values. What we shall find is hinted by the title of the talk. This is joint work with Gunnar G. Peng, Rodolfo Brandão and Ory Schnitzer.
Zoom: https://northwestern.zoom.us/j/95134300986
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TIME Tuesday, April 30, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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May7
EVENT DETAILS
lessTitle: TBA
Speaker: Pankaj Mehta, Boston University
Abstract: TBA
Zoom: https://northwestern.zoom.us/j/93050077443
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TIME Tuesday, May 7, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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May14
EVENT DETAILS
lessTitle: Active Fractal Networks with Stochastic Force Monopoles and Force Dipoles Unravel Subdiffusion of Chromosomal Loci
Speaker: Rony Granek, Ben Gurion University of the Negev
Abstract: Motivated by the well-known fractal packing of chromatin, we study the Rouse-type dynamics of elastic fractal networks with embedded, stochastically driven, active force monopoles and force dipoles that are temporally correlated. We compute, analytically – using a general theoretical framework – and via Langevin dynamics simulations, the mean square displacement (MSD) of a network bead. Following a short time superdiffusive behavior, force monopoles yield anomalous subdiffusion with an exponent identical to that of the thermal system. In contrast, force dipoles do not induce subdiffusion, and the early superdiffusive MSD crosses over to a relatively small, system-size-independent saturation value. In addition, we find that force dipoles may lead to ``crawling" rotational motion of the whole network, reminiscent of that found for triangular micro-swimmers and consistent with general theories of the rotation of deformable bodies. Moreover, force dipoles lead to network collapse beyond a critical force strength, which persists with increasing system size, signifying a true first-order dynamical phase transition. We apply our results to the motion of chromosomal loci in bacteria and yeast cells' chromatin, where anomalous sub-diffusion, MSD∼ t^ν with ν≃ 0.4, were found in both normal and ATP-depleted cells, albeit with different apparent diffusion coefficients. We show that the combination of thermal, monopolar, and dipolar forces in chromatin is typically dominated by the active monopolar and thermal forces, explaining the observed normal cells vs the ATP-depleted cells behavior.
Zoom: https://northwestern.zoom.us/j/96919517661
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TIME Tuesday, May 14, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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May21
EVENT DETAILS
lessTitle: TBA
Speaker: Andrew Stuart, California Institute of Technology
Abstract: TBA
Zoom: TBA
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TIME Tuesday, May 21, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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May28
EVENT DETAILS
lessTitle: TBA
Speaker: Pascale Garaud
Abstract: TBA
Zoom: TBA
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TIME Tuesday, May 28, 2024 at 11:15 AM - 12:15 PM
LOCATION M416, Technological Institute map it
CONTACT Ted Shaeffer ted.shaeffer@northwestern.edu EMAIL
CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)
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Jun10
EVENT DETAILSmore info
lessMcCormick School of Engineering PhD Hooding and Master’s Degree Recognition Ceremony
TIME Monday, June 10, 2024 at 9:00 AM - 11:00 AM
LOCATION Welsh-Ryan Arena
CONTACT Amy Pokrass amy.pokrass@northwestern.edu EMAIL
CALENDAR McCormick School of Engineering and Applied Science
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Jun10
TIME Monday, June 10, 2024 at 2:00 PM - 4:00 PM
LOCATION Welsh-Ryan Arena
CONTACT Amy Pokrass amy.pokrass@northwestern.edu EMAIL
CALENDAR McCormick School of Engineering and Applied Science