17,285 research outputs found
Photoproduction of Quarkonium in Proton-Proton and Nucleus-Nucleus Collisions
We discuss the photoproduction of and at high energy
, and heavy ion colliders. We predict large rates in
interactions at the Fermilab Tevatron %and in heavy-ion interactions at the
CERN LHC. These reactions can be and in and heavy-ion interactions at the
CERN LHC. The is also produced copiously at RHIC. These reactions can
be used to study the gluon distribution in protons and heavy nuclei. We also
show that the different CP symmetries of the initial states lead to large
differences in the transverse momentum spectra of mesonsComment: 4 pgs. with 3 figure
Model of surface instabilities induced by stress
We propose a model based on a Ginzburg-Landau approach to study a strain
relief mechanism at a free interface of a non-hydrostatically stressed solid,
commonly observed in thin-film growth. The evolving instability, known as the
Grinfeld instability, is studied numerically in two and three dimensions.
Inherent in the description is the proper treatment of nonlinearities. We find
these nonlinearities can lead to competitive coarsening of interfacial
structures, corresponding to different wavenumbers, as strain is relieved. We
suggest ways to experimentally measure this coarsening.Comment: 4 pages (3 figures included
Navigation input to level C OFT navigation functional subsystem software requirements (rendezvous onorbit-2)
Navigation software design requirements are presented for the orbital flight test phase of space shuttle. Computer loads for the entire onorbit-2 operation are documented
Integrated orbital servicing study for low-cost payload programs. Volume 2: Technical and cost analysis
Orbital maintenance concepts were examined in an effort to determine a cost effective orbital maintenance system compatible with the space transportation system. An on-orbit servicer maintenance system is recommended as the most cost effective system. A pivoting arm on-orbit servicer was selected and a preliminary design was prepared. It is indicated that orbital maintenance does not have any significant impact on the space transportation system
Empirical model for quasi direct current interruption with a convoluted arc
This contribution considers various aspects of a quasi direct current, convoluted arc produced by a magnetic field (B-field) connected in parallel with an RLC circuit that have not been considered in combination. These aspects are the arc current limitation due to the arc convolution, changes in arc resistance due to the B-field and material ablation, and the relative significance of the RLC circuit in producing an artificial current zero. As a result, it has been possible to produce an empirical equation for predicting the current interruption capability in terms of the B-field magnitude and RLC components
Photometric stability analysis of the Exoplanet Characterisation Observatory
Photometric stability is a key requirement for time-resolved spectroscopic
observations of transiting extrasolar planets. In the context of the Exoplanet
Characterisation Observatory (EChO) mission design, we here present and
investigate means of translating spacecraft pointing instabilities as well as
temperature fluctuation of its optical chain into an overall error budget of
the exoplanetary spectrum to be retrieved. Given the instrument specifications
as of date, we investigate the magnitudes of these photometric instabilities in
the context of simulated observations of the exoplanet HD189733b secondary
eclipse.Comment: submitted to MNRA
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