CO2 laser with simultaneous active and passive Q-switching
Carbon dioxide laser with simultaneous active rotating mirror Q switch and passive absorbing gas cell
Ersoy, O.↗
SEARCH · Engineering Papers
Results for “PASSIVATION”
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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First slip times versus static phase error offset for the first- and passive second-order phase-locked loop
Slip vs static error offset for first and passive second order phase locked loop as function of signal to noise ratio via computer simulation
Holmes, J. K.↗
Stark effect modulation of a passively Q- switched CO2 laser
Stark effect saturable absorber modulation of passively Q switched carbon dioxide laser, using difluoroethane, difluoroethylene, methyl fluoroform, trichloroethylene and vinyl chloride
Claspy, P. C.↗
Spaceborne passive radiators for detector cooling
Specular reflecting passive radiators for synchronous satellite radiation detectors cooling
Gabron, F.↗
The problem of docking with a passive orbiting object which possesses angular momentum
Docking with passive orbiting spinning or tumbling objects for space debris elimination and space rescue operations, describing remotely controlled despinning and retrieval methods
Kaplan, M. H.↗
Optimum radars and filters for the passive sphere system
Studies have been conducted to determine the influence of the tracking radar and data reduction technique on the accuracy of the meteorological measurements made in the 30 to 100 kilometer altitude region by the ROBIN passive falling sphere. A survey of accuracy requirements was made of agencies interested in data from this region of the atmosphere. In light of these requirements, various types of radars were evaluated to determine the tracking system most applicable to the ROBIN, and methods were developed to compute the errors in wind and density that arise from noise errors in the radar supplied data. The effects of launch conditions on the measurements were also examined. Conclusions and recommendations have been made concerning the optimum tracking and data reduction techniques for the ROBIN falling sphere system.
Luers, J. K.↗
A study of passive microwave techniques applied to geologic problems
Passive microwave techniques were applied to geologic problems, in order to establish the microwave properties of representative rocks and minerals, and to examine the feasibility of using microwave radiometry for geologic mapping problems. A review of microwave pertaining to geology was conducted, coupled with laboratory and field investigations of the microwave emission characteristics of various geologic features. The laboratory studies consisted of dielectric constant measurements of rocks and minerals. A majority of field investigations conducted in the western United States, involved the microwave emission charateristics of rock types, and a portion of the study was concerned with microwave properties of mineralized areas. Experiments were also conducted in the vicinity of a coal seam fire in Colorado and across the San Andreas Fault Zone near the Salton Sea, in Southern California.
Edgerton, A. T.↗
Passive microwave studies
The application of passive microwave techniques from airborne and surface platforms for oceanography measurements is discussed. The program is designed to determine: (1) the optimum system parameters, (2) measurement techniques, and (3) the physical phenomena to enable unambiguous all-weather determination of the sea surface properties of sea roughness, surface wind fields, temperature, salinity, sea ice, and pollution. The advantages and disadvantages of the airborne and fixed station operations are examined.
Hollinger, J. P.↗
Passive stability of a spinning Skylab
The results of an analytical investigation of the rotational dynamics of a spinning Skylab space station are presented. The passive stability of motion of a simplified model consisting of a rigid core body with two attached flexible appendages is investigated. The parameter plane stability technique is applied to the specific Skylab case to determine its transient response to external disturbances.
Seltzer, S. M.↗
some new techniques in passive contaminant analysis of space environment simulation chambers
A passive contamination analysis technique in surface sampling for space simulation was developed and evaluated. The KBr pelletizing technique was extended to include heavy oils for infrared analysis. Transmittance and specular reflectance measurements at 2000 A wavelength were found very sensitive to contamination.
Wolff, C. M.↗
Remote sensing of winds and atmospheric turbulence by cross correlation of passive optical signals
A new method is described for the remote measurement of winds and atmospheric turbulence by the cross-correlation of passive optical signals. If small local variations in atmospheric density, temperature or other parameters cause fluctuations in scattered or thermal radiation detected by a radiometer on the ground, then the cross-correlation of fluctuations detected by two radiometers with crossed fields of view can yield turbulence information pertaining to the region about this intersection point. When the fields of view are not quite crossed turbulent eddies will be convected through the fields of view sequentially, and the transit times of the eddies identified by the correlation procedure will yield wind information. The successful application of this technique, detecting fluctuations in scattered sunlight, has demonstrated both the potential, and the present limitations of the method, which are discussed. Results for the power spectrum of the fluctuations and for winds at an altitude of 61 meters are shown.
Montgomery, A. J.↗
A passive pendulum wobble damper for a low spin rate Jupiter flyby spacecraft
When the spacecraft has a low spin rate and precise pointing requirements, the wobble angle must be damped in a time period equivalent to a very few wobble cycles. The design, analysis, and test of a passive pendulum wobble damper are described.
Fowler, R. C.↗
Temperature adaptation of active sodium-potassium transport and of passive permeability in erythrocytes of ground squirrels.
Unidirectional active and passive fluxes of K-42 and Na-24 were measured in red blood cells of ground squirrels (hibernators) and guinea pigs (nonhibernators). As the temperature was lowered, ?active' (ouabain-sensitive) K influx and Na efflux were more considerably diminished in guinea pig cells than in those of ground squirrels. The fraction of total K influx which is ouabain-sensitive in red blood cells of ground squirrels was virtually constant at all temperatures, whereas it decreased abruptly in guinea pig cells as temperature was lowered.
Kimzey, S. L.↗
Minimum weight passive insulation requirements for hypersonic cruise vehicles.
Analytical solutions are derived for two representative cases of the transient heat conduction equation to determine the minimum weight requirements for passive insulation systems of hypersonic cruise vehicles. The cases discussed are the wet wall case with the interior wall temperature held to that of the boiling point of the fuel throughout the flight, and the dry wall case where the heat transferred through the insulation is absorbed by the interior structure whose temperature is allowed to rise.
Ardema, M. D.↗
Passive stability of a spinning Skylab.
The results of an analytical investigation of the rotational dynamics of a spinning Skylab space station are presented. The passive stability of motion of a simplified model consisting of a rigid core body with two attached flexible appendages is investigated. The parameter plane stability technique is applied to the specific Skylab case to determine its transient response to external disturbances.
Seltzer, S. M.↗
Passive seismic experiment
The design, deployment, and operation of the Apollo 16 passive seismic experiment (PSE) are discussed. Since activation, all elements of the PSE have operated as planned, with the exception of the sensor thermal control system. Significant progress in the measurement of meteoroid flux in near-earth space has been made, along with dilineation of active moonquake source regions. The data obtained indicate that moonquakes are concentrated at great depth (800 to 1000 km) and that the apparent disparity between meteoroid flux estimtes based on lunar crater counts and those from earth-based observations can be resolved by seismic measurements in favor of the lower flux indicated by the crater count method. The results obtained from the PSE are summarized and their significance is discussed in detail.
Latham, G. V.↗
Design and testing of a passive, feedback-controlled, variable conductance heat pipe
A passive feedback system, which stabilizes the heat source temperature (T sub s) of a gas loaded heat pipe, was designed and tested. The control of T sub s is accomplished by an auxiliary liquid that senses the heat source and actuates a metal bellows system due to the liquid's thermal expansion. The movement of the bellows varies the gas reservoir volume and leads to a corresponding change of the condensation area of the heat pipe. With methanol as the heat pipe working fluid and perfluoro-n-pentane as the auxiliary liquid, the control capability was found to be T sub s = 31.5 + or - 1.5 C in a power range from 3 to 30 W, compared to T sub s = 33 + or - 3 C with methanol as auxiliary liquid. The change in T sub s was 35 + or - 5.5 C with the bellows held in the closed position.
Schlitt, K. R.↗
Ellipsometric measurements on the passive film prior to the initiation of breakdown in aluminum
The presence of chlorides in aqueous solutions causes pitting attack or stress corrosion cracking in many metals if the oxidation potential is high enough. Results are presented of a series of experiments carried out on 99.99% pure aluminum to determine changes that occur in the ellipsometric parameter of the passive film during incubation period.
Yahalom, J.↗