89,154 research outputs found
Marshall information retrieval and display system (MIRADS)
Program for data management system allows sophisticated inquiries while utilizing simplified language. Online system is composed of several programs. System is written primarily in COBOL with routines in ASSEMBLER and FORTRAN V
Experimental verification of the design of a high efficiency linear injected beam crossed-field amplifier Final report
Design and performance of injected beam crossed field amplifie
State-of-the-art of turbofan engine noise control
The technology of turbofan engine noise reduction is surveyed. Specific topics discussed include: (1) new fans for low noise; (2) fan and core noise suppression; (3) turbomachinery noise sources; and (4) a new program for improving static noise testing of fans and engines
Rendezvous radar requirements analysis for mission 3B
Data are presented verifying the compatibility of currently proposed rendezvous radar measurement accuracies with Mission 3B rendezvous requirements. In addition, data presented indicate a potential for increasing the acceptable time lag between termination of thrusting and availability of accurate measurement data. Additional investigation is recommended to define any acceptable time lag above the current proposed value. Finally, Mission 3B rendezvous performance is shown to be sensitive to variations in the relative downrange position dispersions at insertion. It is therefore recommended that insertion relative state dispersions used in studies of 3B rendezvous be reviewed when results of 3B ascent dispersion studies are available
Simulating Electron Transport and Synchrotron Emission in Radio Galaxies: Shock Acceleration and Synchrotron Aging in Three-Dimensional Flows
We present the first three-dimensional MHD radio galaxy simulations that
explicitly model transport of relativistic electrons, including diffusive
acceleration at shocks as well as radiative and adiabatic cooling in smooth
flows. We discuss three simulations of light Mach 8 jets, designed to explore
the effects of shock acceleration and radiative aging on the nonthermal
particle populations that give rise to synchrotron and inverse-Compton
radiations. We also conduct detailed synthetic radio observations of our
simulated objects. We have gained several key insights from this approach: 1.
The jet head in these multidimensional simulations is extremely complex. The
classical jet termination shock is often absent, but motions of the jet
terminus spin a ``shock-web complex'' within the backflowing jet material of
the head. 2. Understanding the spectral distribution of energetic electrons in
these simulations relies partly upon understanding the shock-web complex, for
it can give rise to distributions that confound interpretation in terms of the
standard model for radiative aging of radio galaxies. 3. The magnetic field
outside of the jet itself becomes very intermittent and filamentary in these
simulations, yet adiabatic expansion causes most of the cocoon volume to be
occupied by field strengths considerably diminished below the nominal jet
value. Thus population aging rates vary considerably from point to point.Comment: 44 pages, 6 figures; to be published in the Astrophysical Journal
(August 2001); higher-quality figures can be found at
http://www.msi.umn.edu/Projects/twj/radjet/radjet.htm
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