22,779 research outputs found
Application of remote sensing technology to land evaluation, planning utilization of land resources, and assessment of westland habitat in eastern South Dakota, parts 1 and 2
The author has identified the following significant results. LANDSAT fulfilled the requirements for general soils and land use information. RB-57 imagery was required to provide the information and detail needed for mapping soils for land evaluation. Soils maps for land evaluation were provided on clear mylar at the scale of the county highway map to aid users in locating mapping units. Resulting mapped data were computer processed to provided a series of interpretive maps (land value, limitations to development, etc.) and area summaries for the users
Consistency of the Shannon entropy in quantum experiments
The consistency of the Shannon entropy, when applied to outcomes of quantum
experiments, is analysed. It is shown that the Shannon entropy is fully
consistent and its properties are never violated in quantum settings, but
attention must be paid to logical and experimental contexts. This last remark
is shown to apply regardless of the quantum or classical nature of the
experiments.Comment: 12 pages, LaTeX2e/REVTeX4. V5: slightly different than the published
versio
Reconstruction of tomographic images of dry aqueous foams
WOS:000328011500007International audienceX-ray tomography offers the possibility to examine the local changes in the structure of a three-dimensional aqueous foam as it flows, allowing a better fundamental understanding of foam rheology and the validation of models. We present an automated algorithm that reconstructs a dry aqueous foam from such images. Our algorithm uses ImageJ to extract from an image the topology of the network of Plateau borders in the foam, and then analyses this network to re-create the films and then the bubbles, and equilibrates the structure in Surface Evolver. We validate our algorithm and demonstrate its precision by applying it to simulated foam structures and analysing the topology and geometry obtained. We then apply our algorithm to a sequence of images from an experiment in which a spherical bead falls under its own weight through a polydisperse dry foam. This allows us to describe the evolution of the foam's bubble volumes with time as well as the distribution of bubble pressure and the forces exerted on a falling sphere. (C) 2013 Elsevier B.V. All rights reserved
Model-based aberration corrected microscopy inside a glass tube
Microscope objectives achieve near diffraction-limited performance only when
used under the conditions they are designed for. In non-standard geometries,
such as thick cover slips or curved surfaces, severe aberrations arise,
inevitably impairing high-resolution imaging. Correcting such large aberrations
using standard adaptive optics can be challenging: existing solutions are
either not suited for strong aberrations, or require extensive feedback
measurements, consequently taking a significant portion of the photon budget.
We demonstrate that it is possible to pre-compute the corrections needed for
high-resolution imaging inside a glass tube based on a priori information only.
Our ray-tracing based method achieved over an order of magnitude increase in
image contrast without the need for a feedback signal.Comment: 9 pages, 3 figures, 1 table. Submitted to Optics Expres
Self-similar stable processes arising from high-density limits of occupation times of particle systems
We extend results on time-rescaled occupation time fluctuation limits of the
-branching particle system with Poisson initial condition. The earlier results in the homogeneous case
(i.e., with Lebesgue initial intensity measure) were obtained for dimensions
only, since the particle system becomes locally extinct if
. In this paper we show that by introducing high density
of the initial Poisson configuration, limits are obtained for all dimensions,
and they coincide with the previous ones if . We also give
high-density limits for the systems with finite intensity measures (without
high density no limits exist in this case due to extinction); the results are
different and harder to obtain due to the non-invariance of the measure for the
particle motion. In both cases, i.e., Lebesgue and finite intensity measures,
for low dimensions ( and
, respectively) the limits are determined by
non-L\'evy self-similar stable processes. For the corresponding high dimensions
the limits are qualitatively different: -valued L\'evy
processes in the Lebesgue case, stable processes constant in time on
in the finite measure case. For high dimensions, the laws of all
limit processes are expressed in terms of Riesz potentials. If , the
limits are Gaussian. Limits are also given for particle systems without
branching, which yields in particular weighted fractional Brownian motions in
low dimensions. The results are obtained in the setup of weak convergence of
S'(R^d)$-valued processes.Comment: 28 page
Kondo Effects and Multipolar Order in the cubic PrTr2Al20 (Tr=Ti, V)
Our single crystal study reveals that PrTr2Al20 (Tr = Ti and V) provides the
first examples of a cubic {\Gamma}3 nonmagnetic ground doublet system that
shows the Kondo effect including a -ln T dependent resistivity. The {\Gamma}3
quadrupolar moments in PrV2Al20 induce anomalous metallic behavior through
hybridization with conduction electrons, such as T^{1/2} dependent resistivity
and susceptibility below ~ 20 K down to its ordering temperature T_O = 0.6 K.
In PrTi2Al20, however, quadrupoles are well-localized and exhibit an order at
T_O = 2.0 K. Stronger Kondo coupling in PrV2Al20 than in PrTi2Al20 suppresses
quadrupolar ordering, and instead promotes hybridization between the {\Gamma}3
doublet and conduction electrons, leading to most likely the quadrupolar Kondo
effect.Comment: 12 pages, 4 figure
3D Simulations of MHD Jet Propagation Through Uniform and Stratified External Environments
We present a set of high-resolution 3D MHD simulations of steady light,
supersonic jets, exploring the influence of jet Mach number and the ambient
medium on jet propagation and energy deposition over long distances. The
results are compared to simple self-similar scaling relations for the
morphological evolution of jet-driven structures and to previously published 2D
simulations. For this study we simulated the propagation of light jets with
internal Mach numbers 3 and 12 to lengths exceeding 100 initial jet radii in
both uniform and stratified atmospheres.
The propagating jets asymptotically deposit approximately half of their
energy flux as thermal energy in the ambient atmosphere, almost independent of
jet Mach number or the external density gradient. Nearly one-quarter of the jet
total energy flux goes directly into dissipative heating of the ICM, supporting
arguments for effective feedback from AGNs to cluster media. The remaining
energy resides primarily in the jet and cocoon structures. Despite having
different shock distributions and magnetic field features, global trends in
energy flow are similar among the different models.
As expected the jets advance more rapidly through stratified atmospheres than
uniform environments. The asymptotic head velocity in King-type atmospheres
shows little or no deceleration. This contrasts with jets in uniform media with
heads that are slowed as they propagate. This suggests that the energy
deposited by jets of a given length and power depends strongly on the structure
of the ambient medium. While our low-Mach jets are more easily disrupted, their
cocoons obey evolutionary scaling relations similar to the high-Mach jets.Comment: Accepted in ApJ, 32 pages, 18 figures, animations available from:
http://www.msi.umn.edu/Projects/twj/newsite/projects/radiojets/movies
Scaling analysis of the magnetic monopole mass and condensate in the pure U(1) lattice gauge theory
We observe the power law scaling behavior of the monopole mass and condensate
in the pure compact U(1) gauge theory with the Villain action. In the Coulomb
phase the monopole mass scales with the exponent \nu_m=0.49(4). In the
confinement phase the behavior of the monopole condensate is described with
remarkable accuracy by the exponent \beta_{exp}=0.197(3). Possible implications
of these phenomena for a construction of a strongly coupled continuum U(1)
gauge theory are discussed.Comment: Added references [1
Transition from overscreening to underscreening in the multichannel Kondo model: exact solution at large N
A novel large-N limit of the multichannel Kondo model is introduced, for
representations of the impurity spin described by Schwinger bosons. Three cases
are found, associated with underscreening, overscreening and exact Kondo
screening of the impurity. The saddle-point equations derived in this limit are
reminiscent of the ``non-crossing approximation'', but preserve the
Fermi-liquid nature of the model in the exactly screened case. Several physical
quantities are computed, both numerically, and analytically in the low-\omega,T
limit, and compared to other approaches.Comment: 4 pages, RevTeX3.0, 2 EPS figures. Published versio
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