SEARCH · Engineering Papers
Results for “backgrounds”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Effects of lubricants - General background
Oil viscosity and chemical composition effects on roller bearing lubricant efficiency
Advanced turbine engine mainshaft lubrication system investigation, phase 2. Part 1 - Background, test elements and results, and conclusions for system performance Final report
Lubricant, thrust bearing, and ring seal tests for supersonic turbine engine mainshaft lubrication system
Recognition of settlement patterns against a complex background
Photointerpretation of aerial color infrared photography for analysis of urban land use
A revision of: Cosmic matter-antimatter annihilation and the gamma-ray background spectrum
Cosmological gamma ray spectrum calculations from matter-antimatter annihilation in universe
Program on application of communications satellites to educational development. Computer-based instruction: A background paper on its status, cost/effectiveness and telecommunications requirements
Status, cost/effectiveness, and telecommunication/satellite requirements of computer-based instruction
Infrared studies of the lunar terrain. I - The background moon
Unlit lunar limb observations at IR wavelengths, presenting temperature charts and thermal abnormalities
Short time-scale optical pulsations in the night sky background
A network of monitoring stations designed to detect large scale fluorescence emission in the atmosphere has been in operation for over two years. The motivation for the search arises from the prediction that an energetic photon burst would be produced in a supernova and this burst, when absorbed in the atmosphere, would produce fluorescence. This paper reports on observations up to February 1971. No supernova-like events have been found, although 4.4 were expected. One class of non-fluorescence events is described that evidence suggests is related to electrical discharge in the atmosphere. Another type of non-fluorescence pulse appears to be related to particle precipitation in the atmosphere.
Rocket study of the X-ray background
The X-ray optical detection system flown on Aerobee 17.08 is described in detail, and the preliminary results of the 24 June 1971 flight are discussed. The optical design, fabrication and parabolic nature of the mirrors, effective aperture of mirror array, and X-ray detectors are considered. Preliminary analysis of data from the flight confirms the extended nature and complex structure of the X-ray source in Virgo. A core of X-ray emission is indicated which is approximately 0.5 deg in diameter and surrounded by an emitting region at least 2 deg across. The Virgo source spectrum is observed to have few low energy photons.
The stratospheric aerosol background.
The current state of observations of the stratosphere aerosol layer is reviewed. Monitoring programs used are briefly reviewed, and the long-term trend of aerosols in the mid-latitude stratosphere is shown. The effects of volcanism on stratospheric aerosol profiles are discussed.
Observational evidence against supernovae being the source of the universal X-ray background.
Explore the source record for details and available documents.
Evaluation of transonic and supersonic wind-tunnel background noise and effects of surface pressure fluctuation measurements.
Explore the source record for details and available documents.
Limit on the energy density in the submillimetre background radiation.
An analysis is made which indicates that the energy density in the submillimeter quanta cannot exceed about 0.4 eV/cu cm averaged over the galactic dimensions, independent of the exact spectral distribution of this radiation. This corresponds to an upper limit of 3.4 K on the radiation temperature in the galactic neighborhood.
Properties of nearby interstellar hydrogen deduced from Lyman-alpha sky background measurements
For a sufficiently rapid relative motion of the solar system and the nearby interstellar gas, neutral atoms may be expected to penetrate the heliosphere before becoming ionized. Recent satellite measurements of the Lyman alpha emission above the geocorona indicate such an interstellar wind of neutral hydrogen emerging from the direction of Sagittarius and reaching to within a few astronomical units of the sun. A detailed model of the scattering of solar Lyman alpha from the spatial distribution of neutral hydrogen in interplanetary space is presented. This asymmetric distribution is established by solar wind and solar ultraviolet ionization processes along the trajectories of the incoming hydrogen atoms. The values of the interstellar density, the relative velocity, and the gas temperature are adjusted to agree with the Lyman alpha measurements. The results may be interpreted in terms of two models, the cold model and the hot model of the interstellar gas, depending on whether galactic Lyman alpha emission is present at its maximum allowable value or negligibly small.
The interstellar line spectra of zeta Ophiuchi and zeta Persei and their relation to the short wavelength microwave background radiation
Thirty-one high dispersion Coude spectrograms of zeta Ophiuchi and seven of zeta Persei were numerically synthesized to produce high resolution, low noise spectra in the interval 3650 A to 4350 that yield data on atomic and molecular absorption in well-defined regions of the interstellar medium. The detection threshold is improved by as much as a factor 5 over single plates. Several interstellar lines were discovered in the zeta Oph - 15km/sec cloud and the zeta Per + 13 km/sec cloud.
Background and general design of the microbial response to space environment experiment (M191) system
Nine different species of organisms were exposed to space flight conditions during the Apollo 16 mission. Each test system was selected because it provided a quantitative method of evaluating some medically important phenomenon. The experiment design and each of the test systems are discussed.
Background of the completed research; relevances to solar physics
Research activities reported consider the atomic structures of highly stripped heavy ions and their modes of formation and destruction in collisions. The lifetime of the metastable 2 3p1 state of the two electron ion F-7(+) was determined by measuring the radiative decay of an excited helium-like fluorine beam, Metastable state quenching measurements were performed on a helium-like ion to obtain the 1 1S0 to 2 3p2 transition probability. Exponential exchange state dependence of X-ray production cross sections was studied in heavy target atoms during collisions with light charged particles.
The short-wavelength spectrum of the microwave background.
Explore the source record for details and available documents.