High voltage divider system Patent
High voltage divider system for attenuating high voltages to convenient levels suitable for introduction to measuring circuits
Mealy, G. E.↗
SEARCH · Engineering Papers
Results for “attenuator”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The accuracy of the Landau-Whitham shock strength rule in some near field situations
Accuracy of shock pressure attenuation in near field sonic boom profiles
George, A. R.↗
Development of four-dimensional atmospheric models (worldwide)
Development of four dimensional atmospheric models from global data for predicting atmospheric attenuation encountered by earth resources observation sensors
Spiegler, D. B.↗
Measurement of the effect of air bubbles on the speed of sound in water
Acoustic velocity in water, examining air bubble effects on pressure pulse attenuation
Gibson, F. W.↗
Some results on coherent radiative phenomena with 0-pi pulses
Coherent radiative phenomena with nontrivial zero-pi pulses propagation behavior in attenuating media
Hopf, F. A.↗
Ground and flight test results for a decelerator towline energy absorber
Parachute decelerator towline energy absorber shock attenuation characteristics, discussing drop test results
Councill, E. L., Jr.↗
Photolysis of formaldehyde at 1470 and 1236 A
Formaldehyde vapor photodecomposition modes by end product analysis, utilizing mixed isotope, radical scavenger, inert gas pressurization and lamp intensity attenuation
Glicker, S.↗
Theoretical and experimental analysis of acoustic linings for ducts with flow
Acoustic linings for attenuation of fan generated noise in turbofan engines, considering interaction between analytical lining performance prediction and flow duct testing
Armstrong, D.↗
The design of exhaust mufflers using linearized theoretical models
Optimal design for noise attenuation by diesel engine exhaust mufflers using linearized acoustic models
Alfredson, R. J.↗
Simulation of 10.6 micron laser space- communications system
Breadboard simulation model of laser space communications system consisting of carbon dioxide laser, transmitter telescope, GaAs phase modulator and attenuator
Peruso, C. J.↗
Temperature dependence of self-induced transparency in ruby
Self induced transparency in ruby attenuator, detailing phase relaxation effects at various temperatures
Asher, I. M.↗
Injection and distribution of liquids in the flow fields of blunt shapes at hypersonic speeds
A possible method for reducing the attenuation of radio transmission from hypersonic vehicles is by injection of a liquid into the flow field. The hot plasma layer surrounding the vehicle could presumably be quenched if the latent heat of the liquid and the heat capacity of the vapor could be utilized efficiently. In the case of stagnation-point injection, the momentum of the liquid could be utilized to modify the bow shock and possibly reduce the initial ionization. To attain these objectives of efficient coolant utilization or modification of the bow shock a knowledge of the liquid injection, atomization, spray penetration, and evaporation processes is required. This report presents the results of a study of liquid injection into hypersonic flow fields. A simplified theory for evaporation distances is derived and is shown to be in qualitative agreement with experimental data. Correlation of experimental data for maximum cross-current penetration of the liquid spray for injection near the shoulder pf a hemisphere cylinder, a sphere 9° cone, and a Mercury model are given. These data were obtained in the Langley Mach 8 variable density tunnel with both liquid nitrogen and water injection to provide a large range of liquid parameters. Flow-field disturbances, as indicated by schlieren photographs and surface pressures, increased with the ratio of coolant mass flux to airstream mass flux. For stagnation-point injection, the maximum shock standoff distance was correlated by the ratio of the liquid jet momentum flux to the airstream momentum flux.
Ivan E. Beckwith↗
Nematic liquid crystals for optical shutters: A concept
Nonmechanical shutter utilizes nematic crystals to attenuate illumination, thus protecting light-sensitive devices such as vidicon or image orthicon tubes and phototubes. Opacity of liquid crystals is controlled by photosensor.
Imus, R. E.↗
Particle detection by a light-scattering technique
Instrument measures concentration of small particles in aqueous medium in terms of amount of light scattered and degree to which light transmission is attenuated. Sensitivity to small particles is optimized because both scattered and transmitted illumination levels are detected by photodiodes.
Kormanyos, S.↗
Design of microstrip components by computer
Development of computer programs for component analysis and design aids used in production of microstrip components is discussed. System includes designs for couplers, filters, circulators, transformers, power splitters, diode switches, and attenuators.
Cisco, T. C.↗
Study and development of acoustic treatment for jet engine tailpipes
A study and development program was accomplished to attenuate turbine noise generated in the JT3D turbofan engine. Analytical studies were used to design an acoustic liner for the tailpipe. Engine ground tests defined the tailpipe environmental factors and laboratory tests were used to support the analytical studies. Furnace-brazed, stainless steel, perforated sheet acoustic liners were designed, fabricated, installed, and ground tested in the tailpipe of a JT3D engine. Test results showed the turbine tones were suppressed below the level of the jet exhaust for most far field polar angles.
Nelson, M. D.↗
Experiment D005: Star occultation navigation
The usefulness of star occultation measurements for space navigation and the determination of a horizon density profile which could be used to update atmospheric models for horizon-based measurement systems were studied. The time of occultation of a known star by a celestial body, as seen by an orbiting observer, determines a cylinder of position, the axis of which is the line through the star and the body center, and the radius of which is equal to the occulting-body radius. The dimming percentage, with respect to the altitude of this grazing ray from the star to the observer, is a percentage altitude for occultation. That is, the star can be assumed to be occulted when it reaches a predetermined percentage of its unattenuated value. The procedure used was to measure this attenuation with respect to time to determine the usefulness of the measurements for autonomous space navigation. In this experiment, the crewmembers had to accomplish star acquisition, identification, calibration, and tracking. Instrumentation was required only for measurement of the relative intensity of the star as it set into the atmosphere.
Silva, R. M.↗
Experiment T001: Entry communication on the Gemini 3 mission
Water addition to the Gemini 3 exhaust plasma was studied to determine its effectiveness in the establishment of communication links during the entry portion of the flight. Attenuation levels were measured with and without water injection at uhf frequencies of 230.4 and 296.8 megahertz and at the C-band frequency of 5690 megahertz. Ultrahigh frequency signals that had been blacked out were restored to significant levels, during early portions of the water-injection sequence, by the high flow rate injection. The C-band signal was enhanced by medium and high flow rate injections during the latter portion of the injection period. The uhf signal recovered during water injection resulted in an antenna pattern that was beamed in the radial direction of injection from the spacecraft. Postflight analysis showed that the uhf recovery data were consistent with injection-penetration theory.
Schroeder, L. C.↗