7,180 research outputs found
Uncertainty estimation via preflight test procedures for a space stabilized inertial navigation system
Preflight operation and alignment of space stabilized inertial navigation system for vertical takeoff aircraf
Anisotropic thermal expansion and magnetostriction of YNiBC single crystals
We present results of anisotropic thermal expansion and low temperature
magnetostriction measurements on YNiBC single crystals grown by high
temperature flux and floating zone techniques. Quantum oscillations of
magnetostriction were observed at low temperatures for starting at
fields significantly below (). Large irreversible,
longitudinal magnetostriction was seen in both, in-plane and along the c-axis,
directions of the applied magnetic field in the intermediate superconducting
state. Anisotropic uniaxial pressure dependencies of were evaluated using
results of zero field, thermal expansion measurements
Addressing \mu-b_\mu and proton lifetime problems and active neutrino masses in a U(1)^\prime-extended supergravity model
We present a locally supersymmetric extension of the minimal supersymmetric
Standard Model (MSSM) based on the gauge group where, except for the supersymmetry breaking scale
which is fixed to be GeV, we require that all non-Standard-Model
parameters allowed by the {\it local} spacetime and gauge symmetries assume
their natural values. The symmetry, which is spontaneously broken
at the intermediate scale, serves to ({\it i}) explain the weak scale
magnitudes of and terms, ({\it ii}) ensure that dimension-3 and
dimension-4 baryon-number-violating superpotential operators are forbidden,
solving the proton-lifetime problem, ({\it iii}) predict {\it bilinear lepton
number violation} in the superpotential at just the right level to accommodate
the observed mass and mixing pattern of active neutrinos (leading to a novel
connection between the SUSY breaking scale and neutrino masses), while
corresponding trilinear operators are strongly supppressed. The phenomenology
is like that of the MSSM with bilinear R-parity violation, were the would-be
lightest supersymmetric particle decays leptonically with a lifetime of s. Theoretical consistency of our model requires the
existence of multi-TeV, stable, colour-triplet, weak-isosinglet scalars or
fermions, with either conventional or exotic electric charge which should be
readily detectable if they are within the kinematic reach of a hadron collider.
Null results of searches for heavy exotic isotopes implies that the re-heating
temperature of our Universe must have been below their mass scale which, in
turn, suggests that sphalerons play a key role for baryogensis. Finally, the
dark matter cannot be the weakly interacting neutralino.Comment: 33 pages, 2 figures, Discussion on proton decay and radiative
neutrino masses augmented, and references adde
Vortex avalanches and self organized criticality in superconducting niobium
In 1993 Tang proposed [1] that vortex avalanches should produce a self
organized critical state in superconductors, but conclusive evidence for this
has heretofore been lacking. In the present paper, we report extensive
micro-Hall probe data from the vortex dynamics in superconducting niobium,
where a broad distribution of avalanche sizes scaling as a power-law for more
than two decades is found. The measurements are combined with magneto-optical
imaging, and show that over a widely varying magnetic landscape the scaling
behaviour does not change, hence establishing that the dynamics of
superconducting vortices is a SOC phenomenon.Comment: 3 pages + 4 figures, a reference added, citation typos fixe
Effects of applying anaerobically digested slurry on soil available organic C and microbiota
Anaerobic digestion of animal slurries and plant residues is a valuable technology to produce bioenergy and fertilizers in organic farming systems, while at the same time reducing propagules of weeds and parasites in the input material. However, the digestion changes the quality of the slurry by reducing its content of organic matter and increasing mineral nitrogen (N) levels. This may have profound impact on soil fauna and microorganisms as well as the biogeochemical processes they drive. Organic farmers fear that application of digested materials may have negative implications for soil fertility by reducing the input of organic matter to the soil, compared to fertilizing with traditional animal slurries or green manures. Hence, it is important to gain knowledge about the short- and long-term effects on microflora and carbon (C) balance in soils fertilized with digested slurry
Real time magneto-optical imaging of vortices in superconductors
We demonstrate here real-time imaging of individual vortices in a NbSe2
single crystal using polarized light microscopy. A new high-sensitivity
magneto-optical (MO) imaging system enables observation of the static vortex
lattice as well as single vortex motion at low flux densities.Comment: 3 pages, 1 figur
Superconductor strip with transport current: Magneto-optical study of current distribution and its relaxation
The dynamics of magnetic flux distributions across a YBaCuO strip carrying
transport current is measured using magneto-optical imaging at 20 K. The
current is applied in pulses of 40-5000 ms duration and magnitude close to the
critical one, 5.5 A. During the pulse some extra flux usually penetrates the
strip, so the local field increases in magnitude. When the strip is initially
penetrated by flux, the local field either increases or decreases depending
both on the spatial coordinate and the current magnitude. Meanwhile, the
current density always tends to redistribute more uniformly. Despite the
relaxation, all distributions remain qualitatively similar to the Bean model
predictions.Comment: RevTeX, 9 pages, 9 figures, submitted to Supercond. Sci. Technol.
Revision: MO image and more refs are adde
Fiber Orientation Estimation Guided by a Deep Network
Diffusion magnetic resonance imaging (dMRI) is currently the only tool for
noninvasively imaging the brain's white matter tracts. The fiber orientation
(FO) is a key feature computed from dMRI for fiber tract reconstruction.
Because the number of FOs in a voxel is usually small, dictionary-based sparse
reconstruction has been used to estimate FOs with a relatively small number of
diffusion gradients. However, accurate FO estimation in regions with complex FO
configurations in the presence of noise can still be challenging. In this work
we explore the use of a deep network for FO estimation in a dictionary-based
framework and propose an algorithm named Fiber Orientation Reconstruction
guided by a Deep Network (FORDN). FORDN consists of two steps. First, we use a
smaller dictionary encoding coarse basis FOs to represent the diffusion
signals. To estimate the mixture fractions of the dictionary atoms (and thus
coarse FOs), a deep network is designed specifically for solving the sparse
reconstruction problem. Here, the smaller dictionary is used to reduce the
computational cost of training. Second, the coarse FOs inform the final FO
estimation, where a larger dictionary encoding dense basis FOs is used and a
weighted l1-norm regularized least squares problem is solved to encourage FOs
that are consistent with the network output. FORDN was evaluated and compared
with state-of-the-art algorithms that estimate FOs using sparse reconstruction
on simulated and real dMRI data, and the results demonstrate the benefit of
using a deep network for FO estimation.Comment: A shorter version is accepted by MICCAI 201
[Report of] Specialist Committee V.4: ocean, wind and wave energy utilization
The committee's mandate was :Concern for structural design of ocean energy utilization devices, such as offshore wind turbines, support structures and fixed or floating wave and tidal energy converters. Attention shall be given to the interaction between the load and the structural response and shall include due consideration of the stochastic nature of the waves, current and wind
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