167 research outputs found
Compensation of distributed delays in integrated communication and control systems
The concept, analysis, implementation, and verification of a method for compensating delays that are distributed between the sensors, controller, and actuators within a control loop are discussed. With the objective of mitigating the detrimental effects of these network induced delays, a predictor-controller algorithm was formulated and analyzed. Robustness of the delay compensation algorithm was investigated relative to parametric uncertainties in plant modeling. The delay compensator was experimentally verified on an IEEE 802.4 network testbed for velocity control of a DC servomotor
Does hybrid density functional theory predict a non-magnetic ground state for delta-Plutonium?
Hybrid density functionals, which replaces a fraction of density functional
theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to
study the structural, magnetic, and electronic properties of delta-Plutonium.
The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%.
Compared to the pure PBE functional, the lattice constants expanded with
respect to the experimental value when the PBE-HF hybrid functionals were
applied. A non-magnetic ground state was realized for 55% HF contribution;
otherwise the ground state was anti-ferromagnetic. The 5f electrons tend to
exhibit slight delocalization or itinerancy for the pure PBE functional and
well-defined localization for the hybrid functionals, with the degree of 5f
electron localization increasing with the amount of HF exchange. Overall, the
performance of the hybrid density functionals do not seem superior to pure
density functionals for delta-Plutonium.Comment: 24 pages (double spaced), 5 figures, 1 tabl
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