11,652 research outputs found
Composite load spectra for select space propulsion structural components
This report summarizes the development for: (1) correlation fields; (2) applications to liquid oxygen post; (3) models for pressure fluctuatios and vibration loads fluctuations; (4) additions to expert systems; and (5) scaling criteria. Implementation to computer code is also described. Demonstration sample cases are included with additional applications to engine duct and pipe bend
Quasilocal Center-of-Mass for Teleparallel Gravity
Asymptotically flat gravitating systems have 10 conserved quantities, which
lack proper local densities. It has been hoped that the teleparallel equivalent
of Einstein's GR (TEGR, aka GR) could solve this gravitational
energy-momentum localization problem. Meanwhile a new idea: quasilocal
quantities, has come into favor. The earlier quasilocal investigations focused
on energy-momentum. Recently we considered quasilocal angular momentum for the
teleparallel theory and found that the popular expression (unlike our
``covariant-symplectic'' one) gives the correct result only in a certain frame.
We now report that the center-of-mass moment, which has largely been neglected,
gives an even stronger requirement. We found (independent of the frame gauge)
that our ``covariant symplectic'' Hamiltonian-boundary-term quasilocal
expression succeeds for all the quasilocal quantities, while the usual
expression cannot give the desired center-of-mass moment. We also conclude,
contrary to hopes, that the teleparallel formulation appears to have no
advantage over GR with regard to localization.Comment: 12 pages, to appear in the proceedings of the 10th Marcel Grossman
meeting (Rio de Janeiro, 2003
Global Diffusion of the Internet VIII: Maximum Resolution Dichotomy for Global Diffusion of the Internet
The Global Diffusion of the Internet (GDI) framework was used to study the progress in the adoption of the Internet in close to 30 countries since 1997. A new methodology in data mining is presented to extend the use of Kiviat diagrams to visualize the framework cast in a supply-demand dichotomy. A maximum resolution topology is derived as an additional tool for exploratory data analysis of such GDI dichotomies
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