83,489 research outputs found
Soil analyses and evaluations at the impact dynamics research facility for two full-scale aircraft crash tests
The aircraft structural crash behavior and occupant survivability for aircraft crashes on a soil surface was studied. The results of placement, compaction, and maintenance of two soil test beds are presented. The crators formed by the aircraft after each test are described
Laboratory requirements for in-situ and remote sensing of suspended material
Recommendations for laboratory and in-situ measurements required for remote sensing of suspended material are presented. This study investigates the properties of the suspended materials, factors influencing the upwelling radiance, and the various types of remote sensing techniques. Calibration and correlation procedures are given to obtain the accuracy necessary to quantify the suspended materials by remote sensing. In addition, the report presents a survey of the national need for sediment data, the agencies that deal with and require the data of suspended sediment, and a summary of some recent findings of sediment measurements
Lattice QCD and Hydro/Cascade Model of Heavy Ion Collisions
We report here on a recent lattice study of the QCD transition region at
finite temperature and zero chemical potential using domain wall fermions
(DWF). We also present a parameterization of the QCD equation of state obtained
from lattice QCD that is suitable for use in hydrodynamics studies of heavy ion
collisions. Finally, we show preliminary results from a multi-stage
hydrodynamics/hadron cascade model of a heavy ion collision, in an attempt to
understand how well the experimental data (e.g. particle spectra, elliptic
flow, and HBT radii) can constrain the inputs (e.g. initial temperature,
freezeout temperature, shear viscosity, equation of state) of the theoretical
model.Comment: 10 pages, 12 figures. Proceedings for the 26th Winter Workshop on
Nuclear Dynamics, Ocho Rios, Jamaica, Jan 2-9, 201
Laboratory requirements for in-situ and remote sensing of suspended material
Recommendations for laboratory and in-situ measurements required for remote sensing of suspended material are presented. This study investigates the properties of the suspended materials, factors influencing the upwelling radiance, and the various types of remote sensing techniques. Calibration and correlation procedures are given to obtain the accuracy necessary to quantify the suspended materials by remote sensing. In addition, the report presents a survey of the national need for sediment data, the agencies that deal with and require the data of suspended sediment, and a summary of some recent findings of sediment measurements
A design study for an optimal non-linear receiver/demodulator Final report
Design study for optimal nonlinear receiver demodulato
Analysis of B-> \phi K Decays in QCD Factorization
We analyze the decay within the framework of QCD-improved
factorization. We found that although the twist-3 kaon distribution amplitude
dominates the spectator interactions, it will suppress the decay rates
slightly. The weak annihilation diagrams induced by penguin
operators, which are formally power-suppressed by order , are
chirally and logarithmically enhanced. Therefore, these annihilation
contributions are not subject to helicity suppression and can be sizable. The
predicted branching ratio of is in
the absence of annihilation contributions and it becomes
when annihilation effects are taken into
account. The prediction is consistent with CLEO and BaBar data but smaller than
the BELLE result.Comment: 13 pages, 3 figures. A major change for the presentation of
branching-ratio predictions. Experimental data are update
Non-linear vortex dynamics and transient effects in ferromagnetic disks
We report a time resolved imaging and micromagnetic simulation study of the
relaxation dynamics of a magnetic vortex in the non-linear regime. We use
time-resolved photoemission electron microscopy and micromagnetic calculations
to examine the emergence of non-linear vortex dynamics in patterned Ni80Fe20
disks in the limit of long field pulses. We show for core shifts beyond ~20-25%
of the disk radius, the initial motion is characterized by distortions of the
vortex, a transient cross-tie wall state, and instabilities in the core
polarization that influence the core trajectories.Comment: 11 pages, 3 figures, submitted to Phys. Rev. Let
Phase soliton and pairing symmetry of a two-band superconductor: Role of the proximity effect
We suggest a mechanism which promotes the existence of a phase soliton --
topological defect formed in the relative phase of superconducting gaps of a
two-band superconductor with s+- type of pairing. This mechanism exploits the
proximity effect with a conventional s-wave superconductor which favors the
alignment of the phases of the two-band superconductor which, in the case of
s+- pairing, are pi-shifted in the absence of proximity. In the case of a
strong proximity such effect can be used to reduce soliton's energy below the
energy of a soliton-free state thus making the soliton thermodynamically
stable. Based on this observation we consider an experimental setup, applicable
both for stable and metastable solitons, which can be used to distinguish
between s+- and s++ types of pairing in the iron-based multiband
superconductors.Comment: New references, added discussion about self-consistency of the GL
description of a phase soliton in the presence of a proximity patc
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