1,025 research outputs found
GASLESS COMBUSTION FRONTS WITH HEAT LOSS
For a model of gasless combustion with heat loss, we use geometric s
ingular
perturbation theory to show existence of traveling combustion fr
onts. We show that the
fronts are nonlinearly stable in an appropriate sense if an Evans fun
ction criterion, which
can be verified numerically, is satisfied. For a solid reactant and exot
hermicity parameter
that is not too large, we verify numerically that the criterion is satisfi
ed
Critical velocity of a mobile impurity in one-dimensional quantum liquids
We study the notion of superfluid critical velocity in one spatial dimension.
It is shown that for heavy impurities with mass exceeding a critical mass
, the dispersion develops periodic metastable branches resulting
in dramatic changes of dynamics in the presence of an external driving force.
In contrast to smooth Bloch Oscillations for , a heavy impurity
climbs metastable branches until it reaches a branch termination point or
undergoes a random tunneling event, both leading to an abrupt change in
velocity and an energy loss. This is predicted to lead to a non-analytic
dependence of the impurity drift velocity on small forces.Comment: 5 pages, 2 figures; New version with Supplemental Material (3 pages,
6 figures); Accepted to PR
Dietary Intake Is Associated with Phthalate Body Burden in a Nationally Representative Sample
Inviscid dynamical structures near Couette flow
Consider inviscid fluids in a channel {-1<y<1}. For the Couette flow
v_0=(y,0), the vertical velocity of solutions to the linearized Euler equation
at v_0 decays in time. At the nonlinear level, such inviscid damping has not
been proved. First, we show that in any (vorticity) H^{s}(s<(3/2)) neighborhood
of Couette flow, there exist non-parallel steady flows with arbitrary minimal
horizontal period. This implies that nonlinear inviscid damping is not true in
any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow and for any
horizontal period. Indeed, the long time behavior in such neighborhoods are
very rich, including nontrivial steady flows, stable and unstable manifolds of
nearby unstable shears. Second, in the (vorticity) H^{s}(s>(3/2)) neighborhood
of Couette, we show that there exist no non-parallel steadily travelling flows
v(x-ct,y), and no unstable shears. This suggests that the long time dynamics in
H^{s}(s>(3/2)) neighborhoods of Couette might be much simpler. Such contrasting
dynamics in H^{s} spaces with the critical power s=(3/2) is a truly nonlinear
phenomena, since the linear inviscid damping near Couette is true for any
initial vorticity in L^2
Meeting unmet need for family planning in rural Uganda through village health worker distribution of emergency contraception: Assessing attitudes and use
On the Vortex-Point Charge Composite: Classical Orbits and Quantum Bound States
The possibility of composite systems arising out of a point charge
interacting with a Nielsen-Olesen vortex in 2+1-dimensions is investigated. It
is shown that classical bounded orbits are possible for certain ranges of
parameters. Long lived metastable states are shown to exist, in a
semi-classical approach, from the study of the effective potential. Loss of
self-adjointness of the Hamiltonian and its subsequent self-adjoint extension
in some cases leads to bound states.Comment: 13 pages, Latex file, For figures e-mail to
"[email protected]
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