112,510 research outputs found
Instrumentation for nondestructive testing of composite honeycomb materials
Program develops instrumentation for nondestructive testing of adhesive-bond strength in honeycomb materials and air coupled inspection methods suitable for large tankage
On the Margulis constant for Kleinian groups, I curvature
The Margulis constant for Kleinian groups is the smallest constant such
that for each discrete group and each point in the upper half space
, the group generated by the elements in which move less
than distance c is elementary. We take a first step towards determining this
constant by proving that if is nonelementary and discrete
with parabolic or elliptic of order , then every point in
is moved at least distance by or where
. This bound is sharp
Development of nondestructive testing techniques for honeycomb heat shields, volume I Final report, 1 Jul. 1964 - 29 Sep. 1966
Development of nondestructive testing system, using ultrasonic techniques, for detecting disbonds in composite honeycomb heat shields of Saturn launch vehicl
Targeted deep surveys of high Galactic latitude HI with the GBT
Over 800 sq. deg. of high Galactic latitude sky have been mapped at 21 cm
with the Robert C. Byrd Green Bank Telescope (GBT). An improved knowledge of
the telescope's beam characteristics has allowed us to reliably map not only
regions of high column density, but also such regions as ELAIS N1, a targeted
Spitzer field, which have very low HI column density. The additional fields we
have observed cover a cross-section of dynamically and chemically interesting
regions as indicated by the presence of intermediate/high velocity gas and/or
anomalous far-IR (dust) colour.Comment: 7 pages, 5 figures. To appear in "The Dynamic ISM: A celebration of
the Canadian Galactic Plane Survey" ASP Conference Serie
Regularization and Renormalization of Chern-Simons Theory
We analyze some features of the perturbative quantization of Chern-Simons
theory (CST) in the Landau gauge. In this gauge the theory is known to be
perturbatively finite. We consider the renormalization scheme in which the
renormalized parameter equals the bare or classical one and show that it
constitutes a natural parametrization for the quantum theory. The reason is
that, although in this renormalization scheme the value of the Green functions
depends on the regularization used, comparison among different regularization
methods shows that the observables (Wilson loops) are the same function of the
shifted monodromy parameter for all BRS invariant regulators used so
far for CST. We also discuss a particular BRS invariant regularization
prescription in which CST is perturbatively defined as the large mass limit of
dimensionally regularized topologically massive Yang-Mills theory. With this
regularization prescription the radiative corrections induced by two-loop
contributions do not entail observable consequences since they can be
reabsorbed by a finite rescaling of the fields only. This very mechanism is
conjectured to take place at higher perturbative orders. Talk presented by G.G.
at the NATO AWR on ``Low dimensional Topology and Quantum Field Theory'', 6-13
September 1992, Cambridge (UK).Comment: 10 pages, Phyzzx, LPTHE 92-4
Accurate near-field calculation in the rigorous coupled-wave analysis method
The rigorous coupled-wave analysis (RCWA) is one of the most successful and
widely used methods for modeling periodic optical structures. It yields fast
convergence of the electromagnetic far-field and has been adapted to model
various optical devices and wave configurations. In this article, we
investigate the accuracy with which the electromagnetic near-field can be
calculated by using RCWA and explain the observed slow convergence and
numerical artifacts from which it suffers, namely unphysical oscillations at
material boundaries due to the Gibb's phenomenon. In order to alleviate these
shortcomings, we also introduce a mathematical formulation for accurate
near-field calculation in RCWA, for one- and two-dimensional straight and
slanted diffraction gratings. This accurate near-field computational approach
is tested and evaluated for several representative test-structures and
configurations in order to illustrate the advantages provided by the proposed
modified formulation of the RCWA.Comment: 13 pages, 12 figure
Change in the North Atlantic circulation associated with the mid-Pleistocene transition
The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20-MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37 degrees 34.285' N, 10 degrees 7.562' W; 2585m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55 degrees N, basin-wide paleoceano-graphic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south-north, and east-west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles.info:eu-repo/semantics/publishedVersio
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Towards a Multimodal Time-Based Empathy Prediction System
We describe our system for empathic emotion recognition. It is based on deep learning on multiple modalities in a late fusion architecture. We describe the modules of our system and discuss the evaluation results. Our code is also available for the research community
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