45,165 research outputs found
Irreversible energy flow in forced Vlasov dynamics
A recent paper [Phys. Plasmas 20, 032304 (2013)] considered the forced linear
Vlasov equation as a model for the quasi-steady state of a single stable plasma
wavenumber interacting with a bath of turbulent fluctuations. This approach
gives some insight into possible energy flows without solving for nonlinear
dynamics. The central result of the present work is that the forced linear
Vlasov equation exhibits asymptotically zero (irreversible) dissipation to all
orders under a detuning of the forcing frequency and the characteristic
frequency associated with particle streaming. We first prove this by direct
calculation, tracking energy flow in terms of certain exact conservation laws
of the linear (collisionless) Vlasov equation. Then we analyze the steady-state
solutions in detail using a weakly collisional Hermite-moment formulation, and
compare with numerical solution. This leads to a detailed description of the
Hermite energy spectrum, and a proof of no dissipation at all orders,
complementing the collisionless Vlasov result.Comment: Small changes for clarit
A flight investigation of simulated data link communications during single-pilot IFR flight
A Flight Data Console (FDC) was developed to allow simulation of a digital communications link to replace the current voice communication system used in air traffic control (ATC). The voice system requires manipulation of radio equipment, read-back of clearances, and mental storage of critical information items, all contributing to high workload, particularly during single-pilot operations. This was an inflight study to determine how a digital communications system might reduce cockpit workload, improve flight proficiency, and be accepted by general aviation pilots. Results show that instrument flight, including approach and landing, can be accomplished quite effectively using a digital data link system for ATC communications. All pilots expressed a need for a back-up voice channel. When included, this channel was used sparingly and principally to confirm any item of information about which there might be uncertainty
Advanced flight design systems subsystem performance models. User guide: Environmental analysis routine library
A user guide for a library of interactive computer routines used to develop performance analysis models of specific environmental control and life support subsystems is presented
Advanced flight design systems subsystem performance models. Sample model: Environmental analysis routine library
A sample environmental control and life support model performance analysis using the environmental analysis routines library is presented. An example of a complete model set up and execution is provided. The particular model was synthesized to utilize all of the component performance routines and most of the program options
Direct evidence for the interaction of the mechanisms of thermally initiated and atom transfer radical polymerization
Maleimido substituted aromatic cyclotriphosphazenes
4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g., hexakis amino or trisaminophenoxy-trisphenoxy-cyclo-triphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics
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