Microorganism sample device
Device, based on gel-impingement technique, collects microorganism specimens from circulating air streams. Device is useful to air pollution studies involving the collection of airborne microbial specimens.
Reed, L. L.↗
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Results for “IMPINGEMENT”
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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A method for analyzing the interaction of an oblique shock wave with a boundary layer
Method for predicting interaction produced by externally generated, oblique shock wave impinging on laminar or turbulent boundary layers
Rose, W. C.↗
A critical evaluation of analytic methods for predicting laminar boundary-layer shock-wave interaction
Critical evaluation of analytic methods of predicting interaction between laminar boundary layer and impinging shock waves
Murphy, J. D.↗
Efficiencies of honeycomb absorbers of solar radiation
Determination of efficiency of solar absorption of honeycomb structure attached to collecting base surface on which incoming solar energy impinges directly on base surface
Bifano, W. J.↗
Three stage potassium vapor turbine test
Three-stage potassium vapor turbine test to determine effects of vapor wetness on impingement damage of different rotor blade materials
Moor, B. L.↗
Reactive stream separation photography Final report
High speed photographic techniques to study impinging streams of propellants in experimental investigation of reactive stream separation
Cordill, J. D.↗
The moon - Global electromagnetic sounding using the solar wind
Solar wind lunar impingement induction of magnetic fields used for global sounding of moon structure
Dyal, P.↗
Propellant condensation on surfaces near an electric rocket exhaust
Spacecraft propellant condensation on low temperature surfaces near cesium ion thruster exhaust, considering neutral atoms impingement and charge exchange
Lyon, W. C.↗
Heat and gas release measurements on liquid hypergolic propellants
Liquid hypergolic propellants heat and gas release determination by calorimetric and PVT measurements, using impinging free jets for propellant mixing
Rodriguez, S. E.↗
Laboratory simulation of impact cratering with high explosives
Impact and explosive craters production in same target material under controlled laboratory conditions, determining depth of burst simulating impingement
Oberbeck, V. R.↗
Experimental investigation of the performance of vortex generators mounted in the supersonic portion of a mixed-compression inlet
Vortex generators were investigated as a means of controlling the throat boundary layer in a Mach 2.5 mixed-compression inlet. With or without throat bleed, the generators were unable to produce the inlet peak recoveries available with good performance bleed. Generators placed on the unbled inlet centerbody ahead of the cowl shock impingement point degraded inlet performance. Generators placed further aft on the unbled centerbody, but ahead of the throat, improved inlet performance at conditions where the terminal shock could cause boundary layer separation. Adding generators to the inlet with throat bleed reduced performance. Bleed aft of the generators degraded the vortex flow field.
Michell, G. A.↗
Formation of giant H II regions following supernova explosions
The principal optical properties of type I supernovae are summarized. These include the light curve and the spectrum. The spectra consist of broad bands with very little continuum. According to the theory presented, the observed light is principally fluorescence, excited in the medium surrounding the supernova by ultraviolet radiation originating from the explosion. It is proposed that the spectrum that impinges on the fluorescent medium while emission is taking place must fall abruptly across the Lyman edge of He II. Such a filtering action is plausibly provided by a much denser internal region, rich in helium, immediately surrounding the exploding object. This will form a Stromgren sphere during the time the intense UV pulse is passing through it. The dense region also slows down the photons below the edge by Thomson scattering, thereby spreading out the UV pulse in time. Various proposed mechanisms for the production of ionization in the Gum nebula are discussed.
Sartori, L.↗
A study of the round jet/plane wall flow field
Impingement angles, between the axisymmetric jet axis and the plane wall, from zero to 15 degrees have been examined for nozzle heights of 0.75, 1.0, 1.5 and 2.0 diameters and for: (1) a fully developed pipe flow, and (2) a relatively uniform exit velocity condition. Velocity measurements have been used to define isotach contours and to determine mass, momentum and energy flux values for the near field (within five diameters) of the jet. Surface pressure measurements have been used to define surface pressure forces and jet centerline trajectories. The geometric and flow conditions examined and the interpretation of the results have been motivated by the externally blown flap STOL aircraft application.
Foss, J. F.↗
Ethiopian Tertiary dike swarms
Mapping of the Ethiopian rift and Afar margins revealed the existence of Tertiary dike swarms. The structural relations of these swarms and the fed lava pile to monoclinal warping of the margins partly reflect a style of continental margin tectonics found in other parts of the world. In Ethiopia, however, conjugate dike trends appear to be unusually strongly developed. Relation of dikes to subsequent margin faulting is ambiguous, and there are instances where the two phenomena are spatially separate and of differing trends. There is no evidence for lateral migration with time of dike injection toward the rift zone. No separate impingement of Red Sea, Gulf of Aden, and African rift system stress fields on the Ethiopian region can be demonstrated from the Tertiary dike swarms. Rather, a single, regional paleostress field existed, suggestive of a focus beneath the central Ethiopian plateau. This stress field was dominated by tension: there is no cogent evidence for shearing along the rift margins. A gentle compression along the rift floor is indicated. A peculiar sympathy of dike hade directions at given localities is evident.
Mohr, P. A.↗
Performance of a neutralizer for electron bombardment thruster
Results of the SERT II flight indicate that the hollow cathode neutralizer not only represents a power and propellant weight penalty but can be a contributing cause to accelerator grid erosion. Tests with a 30-cm diameter thruster show that a neutralizer position of approximately 9 cm axially downstream of the accelerator grid and approximately 9 cm radially away from the outer edge of the accelerator grid and pointing parallel to the thruster axis provides the best overall performance. The estimated grid wear rate was less than 0.08 mm in 10,000 hours. The coupling voltage was approximately 17 volts at a neutralizer flow rate of 22 equivalent milliamperes of mercury and a beam current of 1.5 amperes. Neutralizer power was 31 watts and the effect of neutralizer flow on overall propellant utilization efficiency is a 1.2 percentage point reduction at a thruster utilization efficiency of 90 percent. The neutralizer position defined in tests with a 30 cm thruster was tested with a 15 cm SERT II thruster. When the neutralizer was relocated further downstream with this different orientation, accelerator impingement current due to neutralizer operation was reduced by approximately a factor of seven and was nearly independent of neutralizer operation.
Bechtel, R. T.↗
An investigation of the normal momentum transfer for gases on tungsten
The near monoenergetic beam of neutral helium and argon atoms impinged on a single crystal tungsten target, with the (100) face exposed to the beam. The target was mounted on a torsion balance. The rotation of this torsion balance was monitored by an optical lever, and this reading was converted to a measurement of the momentum exchange between the beam and the target. The tungsten target was flashed to a temperature in excess of 2000 C before every clean run, and the vacuum levels in the final chamber were typically between 0.5 and 1 ntorr. The momentum exchange for the helium-tungsten surface and the argon-tungsten surface combination was obtained over approximately a decade of incoming energy (for the argon gas) at angles of incidence of 0, 30, and 41 deg on both clean and dirty (gas covered) surfaces. The results exhibited a significant variation in momentum transfer between the data obtained for the clean and dirty surfaces. The values of normal momentum accommodation coefficient for the clean surface were found to be lower than the values previously reported.
Moskal, E. J.↗
Peak axial-velocity decay with single- and multi-element nozzles
Jet peak-velocity decay data were obtained for a variety of circular and noncircular single-element and multi-element nozzles for application to externally-blown-flap (EBF) STOL aircraft. These data permit a rational approach, in terms of element type and element spacing, to nozzles designed to promote mixing of the jet exhaust with the surrounding air. Rapid mixing and the resulting lower axial jet velocity decreases the noise caused by the interaction of jet impingement on the flap assembly of EBF STOL aircraft. Empirical relationships are presented that permit the prediction of peak axial-velocity decay curves for a wide spectrum of mixer-type nozzles. The data are useful also in the design of ejector-type noise suppressors and for the suppression of VTOL downwash velocities caused by vertically oriented exhaust nozzles.
Vonglahn, U. H.↗
Exploratory screening tests of several alloys and coatings for automobile thermal reactors
A total of 23 materials (including uncoated ferritic and austenitic iron-base alloys, uncoated nickel and cobalt-base superalloys, and several different coatings on AISI 304 stainless steel) were screened as test coupons on a rack in an automobile thermal reactor. Test exposures were generally 51 hours including 142 thermal cycles of 10 minutes at 1010 + or - 30 C test coupon temperature and 7-minutes cool-down to about 510 C. Materials that exhibited corrosion resistance better than that of Hastelloy X include: a ferritic iron alloy with 6 weight percent aluminum; three nickel-base superalloys; two diffused-aluminum coatings on AISI 304; and a Ni-Cr slurry-sprayed coating on AISI 304. Preliminary comparison is made on the performance of the directly impinged coupons and a reactor core of the same material.
Oldrieve, R. E.↗