56,474 research outputs found
Modelling of dimensional stability of fiber reinforced composite materials
Various methods of predicting the expansion and diffusion properties of composite laminates are reviewed. The prediction equations for continuous fiber composites can be applied to SMC composites as the effective fiber aspect ratio in the latter is large enough. The effect of hygrothermal expansion on the dimensional stability of composite laminates was demonstrated through the warping of unsymmetric graphite/epoxy laminates. The warping is very sensitive to the size of the panel, and to the moisture content which is in turn sensitive to the relative humidity in the environment. Thus, any long term creep test must be carried out in a humidity-controlled environment. Environmental effects in SMC composites and bulk polyester were studied under seven different environments. The SMC composites chosen are SMC-R25, SMC-R40, and SMC-R65
Field dependence of gaseous ion mobility: Test of approximate formulas
The accuracies of three approximate formulas were tested by comparison with special cases for which accurate results could be found. The Wannier free flight theory was found to be superior, and can be extended to yield a formula without further adjustable constants that gives an exact result at low electric fields and good results at medium and high fields. It is applicable for any ion neutral force law and mass ratio
Launch Operations: Prelaunch Activities
Prelaunch activities, countdown and launch for Nimbus 3 satellite
CP violating asymmetry in decays
The CP violating asymmetry from the decay rates of
charged Higgs bosons into the lightest neutral Higgs boson and a boson
is calculated and discussed in the complex MSSM. The contributions from all
complex phases are considered, especially from the top-squark trilinear
coupling, which induces a large contribution to the CP asymmetry.Comment: 19 pages, 10 figures, version published in JHE
Automated calculations for massive fermion production with aITALC
The package aITALC has been developed for the automated calculation of
radiative corrections to two-fermion production at colliders. The
package uses Diana, Qgraf, Form, Fortran, FF, LoopTools, and further unix/linux
tools. Numerical results are presented for .Comment: Contribution to the proceedings of "Loops and Legs in Quantum Field
Theory 2004", Zinnowitz, Usedom Island, Germany, April 2004. 5 pages, latex,
espcrc2, 5 figures, 1 tabl
This before That: Causal Precedence in the Biomedical Domain
Causal precedence between biochemical interactions is crucial in the
biomedical domain, because it transforms collections of individual
interactions, e.g., bindings and phosphorylations, into the causal mechanisms
needed to inform meaningful search and inference. Here, we analyze causal
precedence in the biomedical domain as distinct from open-domain, temporal
precedence. First, we describe a novel, hand-annotated text corpus of causal
precedence in the biomedical domain. Second, we use this corpus to investigate
a battery of models of precedence, covering rule-based, feature-based, and
latent representation models. The highest-performing individual model achieved
a micro F1 of 43 points, approaching the best performers on the simpler
temporal-only precedence tasks. Feature-based and latent representation models
each outperform the rule-based models, but their performance is complementary
to one another. We apply a sieve-based architecture to capitalize on this lack
of overlap, achieving a micro F1 score of 46 points.Comment: To appear in the proceedings of the 2016 Workshop on Biomedical
Natural Language Processing (BioNLP 2016
Wash-Out in N_2-dominated leptogenesis
We study the wash-out of a cosmological baryon asymmetry produced via
leptogenesis by subsequent interactions. Therefore we focus on a scenario in
which a lepton asymmetry is established in the out-of-equilibrium decays of the
next-to-lightest right-handed neutrino. We apply the full classical Boltzmann
equations without the assumption of kinetic equilibrium and including all
quantum statistical factors to calculate the wash-out of the lepton asymmetry
by interactions of the lightest right-handed state. We include scattering
processes with top quarks in our analysis. This is of particular interest since
the wash-out is enhanced by scatterings and the use of mode equations with
quantum statistical distribution functions. In this way we provide a
restriction on the parameter space for this scenarios.Comment: 26 pages, 4 figures, profound revision, exposition is now in flavor
notation, one plot and discussion added, numerical error corrected, three
plots changed, text polished, main results remain unchanged, reference
added,matches published versio
Automated use of DIANA for two-fermion production at colliders
We describe packages for the calculation of radiative corrections to
two-fermion production at colliders. The packages use DIANA, and also QGRAF,
FORM, Fortran, and further unix/linux tools. The one-loop calculations in the
Standard Model are highly automatized with the package aITALC. Further, the
automatic determination of all the matrix elements for two-loop corrections to
massive Bhabha scattering in QED and the classification of their topologies and
prototypes is done with DIANA. A generalization to the Standard Model is
straightforward.Comment: To appear in the proceedings of ACAT03, Dec 2003, KEK, Japa
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