132 research outputs found
Piecewise Linear and Nonlinear Window Functions for Modelling of Nanostructured Memristor Device
The present paper reports two new window functions viz. piecewise linear window function and nonlinear window function for modelling of the nanostructured memristor device. The piecewise linear window function can be used for modelling of symmetric pinched hysteresis loop in I-V plane (for digital memory applications) and the nonlinear window function can be used for modelling of nonlinear pinched hysteresis loop in I-V plane (for analog memory applications). Flexibility in the parameter selection is the main attractive feature of these window functions
Piecewise Linear and Nonlinear Window Functions for Modelling of Nanostructured Memristor Device
The present paper reports two new window functions viz. piecewise linear window function and nonlinear window function for modelling of the nanostructured memristor device. The piecewise linear window function can be used for modelling of symmetric pinched hysteresis loop in I-V plane (for digital memory applications) and the nonlinear window function can be used for modelling of nonlinear pinched hysteresis loop in I-V plane (for analog memory applications). Flexibility in the parameter selection is the main attractive feature of these window functions
GRACE storage-runoff hystereses reveal the dynamics of regional watersheds
We characterize how regional watersheds function as simple, dynamic systems
through a series of hysteresis loops using measurements from NASA's Gravity
Recovery and Climate Experiment (GRACE) satellites. These loops illustrate
the temporal relationship between runoff and terrestrial water storage in
three regional-scale watersheds (> 150 000 km2) of the
Columbia River Basin, USA and Canada. The shape and size of the hysteresis
loops are controlled by the climate, topography, and geology of the
watershed. The direction of the hystereses for the GRACE signals moves in
opposite directions from the isolated groundwater hystereses. The subsurface
water (soil moisture and groundwater) hystereses more closely resemble the
storage-runoff relationship of a soil matrix. While the physical processes
underlying these hystereses are inherently complex, the vertical integration
of terrestrial water in the GRACE signal encapsulates the processes that
govern the non-linear function of regional-scale watersheds. We use
this process-based understanding to test how GRACE data can be applied
prognostically to predict seasonal runoff (mean Nash-Sutcliffe Efficiency of
0.91) and monthly runoff during the low flow/high demand month of August
(mean Nash-Sutcliffe Efficiency of 0.77) in all three watersheds. The global
nature of GRACE data allows this same methodology to be applied in other
regional-scale studies, and could be particularly useful in regions with
minimal data and in trans-boundary watersheds
High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers
Van der Waals coefficients for the heteronuclear alkali-metal dimers of Li,
Na, K, Rb, Cs, and Fr are calculated using relativistic ab initio methods
augmented by high-precision experimental data. We argue that the uncertainties
in the coefficients are unlikely to exceed about 1%.Comment: 11 pages, 2 figs, graphicx.st
Dynamics of liquid He-4 in confined geometries from Time-Dependent Density Functional calculations
We present numerical results obtained from Time-Dependent Density Functional
calculations of the dynamics of liquid He-4 in different environments
characterized by geometrical confinement. The time-dependent density profile
and velocity field of He-4 are obtained by means of direct numerical
integration of the non-linear Schrodinger equation associated with a
phenomenological energy functional which describes accurately both the static
and dynamic properties of bulk liquid He-4. Our implementation allows for a
general solution in 3-D (i.e. no symmetries are assumed in order to simplify
the calculations). We apply our method to study the real-time dynamics of pure
and alkali-doped clusters, of a monolayer film on a weakly attractive surface
and a nano-droplet spreading on a solid surface.Comment: q 1 tex file + 9 Ps figure
Unconventional Cosmology
I review two cosmological paradigms which are alternative to the current
inflationary scenario. The first alternative is the "matter bounce", a
non-singular bouncing cosmology with a matter-dominated phase of contraction.
The second is an "emergent" scenario, which can be implemented in the context
of "string gas cosmology". I will compare these scenarios with the inflationary
one and demonstrate that all three lead to an approximately scale-invariant
spectrum of cosmological perturbations.Comment: 45 pages, 10 figures; invited lectures at the 6th Aegean Summer
School "Quantum Gravity and Quantum Cosmology", Chora, Naxos, Greece, Sept.
12 - 17 2012, to be publ. in the proceedings; these lecture notes form an
updated version of arXiv:1003.1745 and arXiv:1103.227
Ozone inactivation of acid stressed Listeria monocytogenes and Listeria innocua in orange juice using a bubble column
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