6,593 research outputs found
Assisting Community Foundations with Branding, Standards, and Marketing: Lessons Learned
Michigan has been intentional about growing community foundations since the late 1980s. Local efforts have been supported by the Council of Michigan Foundations with funding from the W.K. Kellogg Foundation. FERA (Formative Evaluation Research Associates), an independent evaluation group, and Williams Group, a strategic communications firm, have documented growth, identified supports and obstacles, and developed lessons learned. This document is part of a larger set of lessons learned across multiple state-wide initiatives about community foundation growth
Lorentz Space Estimates for the Ginzburg-Landau Energy
In this paper we prove novel lower bounds for the Ginzburg-Landau energy with
or without magnetic field. These bounds rely on an improvement of the "vortex
balls construction" estimates by extracting a new positive term in the energy
lower bounds. This extra term can be conveniently estimated through a Lorentz
space norm, on which it thus provides an upper bound. The Lorentz space
we use is critical with respect to the expected vortex profiles
and can serve to estimate the total number of vortices and get improved
convergence results.Comment: 52 pages, 1 figur
Compressible, inviscid Rayleigh-Taylor instability
We consider the Rayleigh-Taylor problem for two compressible, immiscible,
inviscid, barotropic fluids evolving with a free interface in the presence of a
uniform gravitational field. After constructing Rayleigh-Taylor steady-state
solutions with a denser fluid lying above the free interface with the second
fluid, we turn to an analysis of the equations obtained from linearizing around
such a steady state. By a natural variational approach, we construct normal
mode solutions that grow exponentially in time with rate like e^{t
\sqrt{\abs{\xi}}}, where is the spatial frequency of the normal mode. A
Fourier synthesis of these normal mode solutions allows us to construct
solutions that grow arbitrarily quickly in the Sobolev space , which leads
to an ill-posedness result for the linearized problem. Using these pathological
solutions, we then demonstrate ill-posedness for the original non-linear
problem in an appropriate sense. More precisely, we use a contradiction
argument to show that the non-linear problem does not admit reasonable
estimates of solutions for small time in terms of the initial data.Comment: 31 pages; v2: updated grant informatio
Passive scalars, moving boundaries, and Newton's law of cooling
We study the evolution of passive scalars in both rigid and moving slab-like
domains, in both horizontally periodic and infinite contexts. The scalar is
required to satisfy Robin-type boundary conditions corresponding to Newton's
law of cooling, which lead to nontrivial equilibrium configurations. We study
the equilibration rate of the passive scalar in terms of the parameters in the
boundary condition and the equilibration rates of the background velocity field
and moving domain.Comment: 27 page
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