This paper describes a method for correcting the dynamically induced bias errors in wind tunnel model att i tude measurements using measured modal properties of the model system. At NASA Langley Research Center, the predominant instrumentation used to measure model attitude is a servo-accelerometer device that senses the model attitude with respect to the local vertical. Under smooth wind tunne...

Electric traction system uses voltage source inverter technology for three phase electric locomotives. This paper proposes Z source inverters to control the speed of locomotive drives. The acceleration region and free running region of operation of locomotive is considered for analysis. The control strategy for Z source inverter used is simple boost control. The speed control method for tractio...

A multi-laboratory collaboration is studying the feasibility of building a muon collider, the first phase of which maybe a neutrino factory. The phase space occupied by the muons is very large and needs to be cooled several orders of magnitude for either machine, 100,000 to 1 million for the collider and ten to 100 for the factory. Ionization cooling is the baseline method for muon cooling. Thi...

An important benefit in adopting multi-mode hybrid powertrains is the possibility of downsizing the electric motor/generator (M/G) units. This paper discusses design optimization of M/G full-load operation envelopes. A three-dimensional operation space analysis is introduced and the full-load speed-torque envelopes of M/G units appear as constraints in the powertrain operation space. The analys...

A minimal residual smoothing (MRS) technique is employed to accelerate the convergence of the multi-level iterative method by smoothing the residuals of the original iterative sequence. The sequence with smoothed residuals is reintroduced into the multi-level iterative process. The new sequence generated by this acceleration procedure converges much faster than both the sequence generated by th...

During major magnetic storms enhanced fluxes of relativistic electrons in the inner magnetosphere have been observed to correlate with ULF waves. The enhancements can take place over a period of several hours. In order to account for such a rapid generation of relativistic electrons, we examine the mechanism of transit-time acceleration of electrons by low-frequency fast-mode MHD waves, here th...

Magnetohydrodynamic (MHD) turbulence is an important agent of energetic particle acceleration. Focusing on the compressible properties magnetic turbulence, we adopt test method to study acceleration from Alfv\'en, slow and fast modes in four regimes that may appear a realistic astrophysical environment. Our studies show (1) second-order Fermi mechanism drives particles cascade processes three b...