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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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At least 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Modelling and Analysis of the Corrosion Characteristics of Ferritic-Martensitic Steels in Supercritical Water

The dependencies of weight gain of 9-12 Cr ferritic-martensitic steels in supercritical water on each of seven principal independent variables (temperature, oxygen concentration, flow rate, exposure time, and key chemical composition and surface condition of steels) have been predicted using a supervised artificial neural network (ANN). The relative significance of each independent variable was uncovered by fuzzy curve analysis, which ranks temperature and exposure time as the most important. The optimized ANN, not only satisfactorily represents the experimentally-known non-linear relationships between the corrosion characteristics of F-M steels and the key independent variables (demonstrating the effectiveness of this technique), but also predicts and reveals that the effects of oxygen concentration on the weight gains, to a certain degree, is influenced by the flow rate and temperature. Finally, according to the ANN predicted-results, departure of oxidation kinetics from the parabolic law, and basic cause of chromium content in steel substrate influencing the corrosion rate, and the synergetic effects of dissolved oxygen concentration, flow rate, and temperature, are discussed and analyzed.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Investigating the contribution of grown new particles to cloud condensation nuclei with largely varying preexisting particles – Part 1: Observational data analysis

This study employed multiple techniques to investigate the contribution of grown new particles to the number concentration of cloud condensation nuclei (CCN) at various supersaturation (SS) levels at a rural mountain site in the North China Plain from 29 June to 14 July 2019. On 8 new particle formation (NPF) days, the total particle number concentrations (N cn ) were 8.4 ± 6.1×10 3 cm -3 , which was substantially higher compared to 4.7 ± 2.6×10 3 cm -3 on non-NPF days. However, the CCN concentration (Nccn) at 0.2 % SS and 0.4 % SS on the NPF days was significantly lower than those observed on non-NPF days (p<0.05). This was due to the lower cloud activation efficiency of preexisting particles resulting from organic vapor condensation and smaller number concentrations of preexisting particles on NPF days. A case-by-case examination showed that the grown new particles only yielded a detectable contribution to N ccn at 0.4 % SS and 1.0 % SS during the NPF event on 1 July 2019, accounting for 12 % ± 11 % and 23 % ± 12 % of N ccn , respectively. The increased N ccn during two other NPF events and at 0.2 % SS on 1 July 2019 were detectable but determined mainly by varying preexisting particles rather than grown new particles. In addition, the hygroscopicity parameter values, concentrations of inorganic and organic particulate components, and surface chemical composition of different sized particles were analyzed in terms of chemical drivers to grow new particles. The results showed that the grown new particles via organic vapor condensation generally had no detectable contribution to N ccn but incidentally did. However, this conclusion was drawn from a small size of observational data, leaving more observations, particularly long-term observations and the growth of preexisting particles to the CCN required size, needed for further investigation.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1966

The atmosphere of Mercury.

Mercury atmospheric temperature, composition and surface pressure and effect of nonsynchronous rotation

PLANETARY ATMOSPHERE↗
NASA NTRS1968

Surveyor 5 science results.

Surveyor 5 alpha particle backscattering instrument measurement, TV pictures of lunar surface elemental composition and magnetic and mechanical measurements

Jaffe, L. D.↗
NASA NTRS1972

Mechanics of load transfer at the fiber/matrix interface

Methods for measuring and predicting interface bond stresses and interface bond strength are described. Geometric and material variables which influence interface stress and interface bond strength are identified. The dependence of composite fracture surface characteristics on bond strength is illustrated. Parameters for selecting constituents to yield specified interface bond strength are recommended.

Chamis, C. C.↗
NASA NTRS1972

Spectrophotometric studies of the photometric function, composition, and distribution of the surface materials of Mars.

Results of a program of mapping the surface of Mars carried out at a spatial resolution of 300 to 500 km during the 1969 opposition at IR (0.60 to 2.27 microns). Spectral albedo curves were obtained for 150 mare and desert areas. These curves fall into two well-defined and fairly uniform color-albedo groups corresponding to mare and desert units. The lack of areas with color and albedo that are distinctively different from those of these groups is interpreted as an indication that the surface of Mars consists of basically only two types of materials. Laboratory comparison data support a model of the Martian regolith that suggests that the general color of these surface units is due to a limonite stain coating the particles of lithic soils. Features in the spectral albedo curves at 1.6 and 2.1 microns are interpreted as being due to the H2O ice on the surface or in the Martian atmosphere.

Binder, A. B.↗
NASA NTRS1974

Infrared remote sounding

Atmospheric radiation was measured as a function of wavelength, position, angle, and time. Radiation was determined by temperature, cloud (aerosol), composition, and surface emissivity measurements. The theory of radiative transfer is reviewed, along with retrieval methods. Instruments onboard space probes for infrared remote sounding of planetary atmospheres are also described.

Rodgers, C. D.↗
NASA NTRS1976

The meteorology of Jupiter

From the point of view of meteorology the most important differences between Jupiter and the earth are related to the fact that Jupiter has an appreciable internal energy source and probably lacks a solid surface. The composition and vertical structure of the Jovian atmosphere is considered along with the composition of Jovian cloud particles, turbulence in Jupiter's atmosphere, data on the horizontal structure and motions of the atmosphere, and questions related to the longevity of Jupiter's clouds. Attention is given to the barotropic characteristics of Jupiter's atmosphere, the radiation balance in the atmosphere of the earth and of Jupiter, and studies of the Great Red Spot.

Ingersoll, A. P.↗
NASA NTRS1978

The evolution of the atmosphere of the earth

Computer simulations of the evolution of the earth's atmospheric composition and surface temperature have been carried out. The program took into account changes in the solar luminosity, variations in the earth's albedo, the greenhouse effect, variation in the biomass, and a variety of geochemical processes. Results indicate that prior to two billion years ago the earth had a partially reduced atmosphere, which included N2, CO2, reduced carbon compounds, some NH3, but no free H2. Surface temperatures were higher than now, due to a large greenhouse effect. When free O2 appeared the temperature fell sharply. Had earth been only slightly further from the sun, runaway glaciation would have occurred at that time. Simulations also indicate that a runaway greenhouse would have occurred early in earth's history had earth been only a few percent closer to the sun. It therefore appears that, taking into account the possibilities of either runaway glaciation or a runaway greenhouse effect, the continuously habitable zone about a solar-type star is rather narrow, extending only from roughly 0.95 to 1.01 AU.

Hart, M. H.↗
NASA NTRS1978

The Galilean satellites of Jupiter - Four worlds

A broad survey is presented of our current knowledge of the Galilean satellites. Attention is given to the physical properties (size, masses, densities, and rotation) and to the surface properties (albedo, surface markings, composition, and physical state) of the satellites. In particular, Io's atmosphere is considered with emphasis on the sodium, hydrogen and sulfur clouds and the ionosphere. The atmospheres of the other satellites are examined briefly and consideration is given to models of planetary origin, evolution and interior structure.

Johnson, T. V.↗
NASA NTRS1978

Research on lunar materials

Abstracts of 14 research reports relating to investigations of lunar samples are presented. The principal topics covered include: (1) optical properties of surface and core samples; (2) chemical composition of the surface layers of lunar grains: Auger electron spectroscopy of lunar soil and ground rock samples; (3) high frequency electrical properties of lunar soil and rock samples and their relevance for the interpretation of lunar radar observations; (4) the electrostatic dust transport process; (5) secondary electron emission characteristics of lunar soil samples and their relevance to the dust transportation process; (6) grain size distribution in surface soil and core samples; and (7) the optical and chemical effects of simulated solar wind (2keV proton and a particle radiation) on lunar material.

Gold, T.↗
NASA NTRS1976

What's new on the moon?

As a result of the Apollo program and other lunar probes, questions that remained unsolved during centuries of speculation and scientific study can now be answered concerning the composition, core, surface, age, and history of the moon. Data obtained from lunar samples and instruments on the lunar surface are being used to gain insight into the history of the earth and the other planets, planetary evolution, the development of planetary magnetic fields, the nature of the solar wind, and how the Sun operates. Projects suggested for using the moon to increase understanding of geophysics are described.

Source record↗
NASA NTRS1982

Charge-coupled device (CCD) television camera for NASA's Galileo mission to Jupiter

The CCD detector under construction for use in the slow-scan television camera for the NASA Galileo Jupiter orbiter to be launched in 1985 is presented. The science objectives and the design constraints imposed by the earth telemetry link, platform residual motion, and the Jovian radiation environment are discussed. Camera optics are inherited from Voyager; filter wavelengths are chosen to enable discrimination of Galilean-satellite surface chemical composition. The CCO design, an 800 by 800-element 'virtual-phase' solid-state silicon image-sensor array with supporting electronics, is described with detailed discussion of the thermally generated dark current, quantum efficiency, signal-to-noise ratio, and resolution. Tests of the effect of ionizing radiation were performed and are analyzed statistically. An imaging mode using a 2-1/3-sec frame time and on-chip summation of the signal in 2 x 2 blocks of adjacent pixels is designed to limit the effects of the most extreme Jovian radiation. Smearing due to spacecraft/target relative velocity and platform instability will be corrected for via an algorithm maximizing spacial resolution at a given signal-to-noise level. The camera is expected to produce 40,000 images of Jupiter and its satellites during the 20-month mission.

Klaasen, K. P.↗