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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 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRS1970

Relationship between vegetation reflectance spectra and soil geochemistry: New data from Catheart Mountain, Maine

Spectral reflectance curves for red spruce and balsam fir in the 350- to 1100-nanometer region showed differences between specimens growing over and away from a concealed copper deposit at Catheart Mountain, Maine. A sample group of 15 anomalous spruce, 9 background spruce, 10 anomalous fir, and 10 background fir was studied. Measurements of copper and molybdenum contents in the supporting soil were used to categorize the trees as anomalous or background. Analyses using parametric and nonparametric statistical tests were performed to establish whether significant differences existed between the anomalous and background groups. At the 95% confidence level, significant differences were found to exist for both species, generally in the chlorophyll band centered at about 550 nanometers and in the region from 700 to 900 nanometers.

Canney, F. C.↗
NASA NTRS1972

Mare Imbrium lava flows and their relationship to color boundaries, part M

The Apollo 15 metric camera photography provided a number of spectacular views of most of the southern and central portions of the unique systems of major lava flows that stretch diagonally across Mare Imbrium from the general area of Euler Crater to a point east of Le Verrier Crater. A preliminary examination of the photographs indicates that the source of the material comprising the major flows is situated to the west of Euler Crater and south of the limits of the photographic coverage. The photographs also show clearly that most, if not all, the mare ridges included were formed after the solidification of the flows. Few color boundaries exist in the area of metric photography where the illumination angle is low enough to show the fronts of some of the very thin flows. However, patches of redder material lying northeast of Mt. Lahire are found to be enclosed by low flow fronts, confirming the theory that the redder material represents an earlier filling of the Imbrium basin.

Whitaker, E. A.↗
NASA NTRS1972

Relationship of dislocation density of silicon to solar cell current loss at low temperature

Large decreases in short circuit current of silicon solar cells have been reported to occur as temperature is decreased below -60 C. Experimental results are presented which relate high dislocation density of the silicon bulk material of cells to the large current loss effect. Solar cells were made by the same processes from a variety of silicon materials, namely low-dislocation-density, high-dislocation-density float-zone, and Czochralski silicon. All cells were etched in a manner which revealed the dislocation density of the cell bulk silicon. It was found that every cell made from any of the various low-dislocation starting materials obtained from three suppliers still had a low-dislocation bulk after cell processing, and that all such cells belonged to category good. Cells made from float-zone materials showed high dislocation densities in their bulk and either fell into category poor, or had intermediate losses of short-circuit current at low temperature.

Mandelkorn, J.↗
NASA NTRS1972

An investigation of relationships between meso- and synoptic-scale phenomena

Methods based on the vorticity equation, the adiabatic method, the curvature of the vertical wind profile, and the structure of synoptic waves are used to determine areas of positive vertical motion in the mid-troposphere for a period in each season. Parameters indicative of low-level moisture and conditional instability are areas in which mesoscale systems may be present. The best association between mesoscale and synoptic-scale phenomena was found for a period during December when synoptic-scale systems were well developed. A good association between meso- and synoptic-scale events also was found for a period during March, while the poorest association was found for a June period. Daytime surface heating apparently is an important factor in the formation of mesoscale systems during the summer. It is concluded that the formation of mesoscale phenomena may be determined essentially from synoptic-scale conditions during winter, late fall, and early spring.

Scoggins, J. R.↗
NASA NTRS1972

Observed relationships between electric fields and auroral particle precipitation

Simultaneous electric field and plasma observations with the low altitude, polar orbiting satellite Injun (Hawkeye) 5 provided a comprehensive survey of convection electric fields and their association with magnetospheric plasma phenomena. The most prominent features of the convection electric fields are reversals located at high magnetic latitudes, with generally anti sunward convection poleward convection equatorward of the electric field reversal location. The electric field reversal is interpreted as the boundary between open and closed magnetic field lines. To investigate the electric field and plasma interrelationships during a polar magnetic substorm, a series of passes obtained prior to and during a substrom is presented. Large, anti sunward convection velocities were detected over the polar cap several tens of minutes before the onset of the expansive phase of the substrom. These convection velocities gradually decreased during the decay phase of the substrom. Measurements of enhanced anti sunward flow over the polar cap region are generally consistent with concepts of the origin of substroms.

Gurnett, D. A.↗
NASA NTRS1971

Relationship between siderophilic-element content and oxidation state of ordinary chondrites.

The concentrations of Ni and Ir have been determined by neutron activation in a suite of ordinary chondrites for which accurate ferromagnesian-mineral compositional data were available. Although hiatus between the individual groups exist, the trends within the groups are in keeping with the hypothesis that the ordinary chondrites form a continuous fractionation sequence. A significant negative correlation is observed between the abundance of Ni or Ir and the Fe content of the ferromagnesian minerals in the H and L groups, and for Ir in the LL group, as expected if the metal-silicate fractionation and the variation in oxidation states were produced by the same or related processes. The Ir/Ni ratio decreases by a factor of 1.2 between the H and LL groups. This fractionation must have occurred at an early stage in the condensation phase of the solar nebula.

Mueller, O.↗
NASA NTRS1971

The relationship between certain characteristics of industrial research proposals and their subsequent disposition.

The ideas produced by three idea generation groups operating within a large industrial R & D laboratory were studied over a period of two years. Data were collected in order to relate idea dispositions by management to subjective evaluations provided by respondents representing the technical staff and to study the roles of urgency, predictability, and expected time horizon in the disposition decision. The findings are (1) a significant positive correlation was found between idea dispositions and associated subjective evaluations despite the fact that management did not know the subjective evaluations at the time the disposition decisions were made; (2) urgency was the dominant consideration in the disposition decisions, but predictability and expected time horizon were dominant in the subjective evaluations; (3) predictability and time horizon are covariants; and (4) management hedges by shelving marginal ideas. Implications for R & D management are drawn.

Baker, N. R.↗
NASA NTRS1972

Micrometeorite craters on lunar glass particles - The relationship between radial fracture zones and spall zones.

Discussion of the microimpact-crater morphology observed by scanning electron microscopy on a glass bead (nearly 580 microns in maximum diameter) recovered from zone A of the Luna 16 sample. The microcrater has a diameter of approximately 200 microns and a centrally located melted region or pit that is slightly elevated above the surrounding area. Around the pit is a radial fracture zone half of which has spalled off. The spall zone is more than half again as large as the radial fracture zone.

Glass, B. P.↗
NASA NTRS1972

The relationship of theory and experiment in the D-region.

To monitor the descriptive parameters of the lower ionosphere and construct a model which predicts their temporal and spatial variations is a particularly difficult task. In a given situation simultaneous measurements should be conducted of ionization sources, the altitude distribution of all neutral atmospheric constituents, the identification, number density, and altitude distribution of different species of positive and negative ions and electrons. These results are compared with theoretical predictions to serve as boundary conditions and guides to modification of the theory. It has not been possible to realize this goal in lower ionosphere research because of the large number of parameters and since certain parameters, such as positive ion species distribution and nitric oxide, can only be measured with the aid of sounding rockets. To illustrate the difficulty, recent positive ion composition measurements are compared with predictions utilizing clustering of ions and neutrals to form hydrated ions.

Aikin, A. C.↗
NASA NTRS1972

Further observations on the relationship of EMG and muscle force

Human skeletal muscle may be regarded as an electro-mechanical transducer. Its physiological input is a neural signal originating at the alpha motoneurons in the spinal cord and its output is force and muscle contraction, these both being dependent on the external load. Some experimental data taken during voluntary efforts around the ankle joint and by direct electrical stimulation of the nerve are described. Some of these experiments are simulated by an analog model, the input of which is recorded physiological soleus muscle EMG. The output is simulated foot torque. Limitations of a linear model and effect of some nonlinearities are discussed.

Agarwal, G. C.↗
NASA NTRS1972

A dynamic response and eye scanning data base useful in the development of theories and methods for the description of control/display relationships

A set of specially prepared digital tapes is reported which contain synchronized measurements of pilot scanning behavior, control response, and vehicle response obtained during instrument landing system approaches made in a fixed-base DC-8 transport simulator. The objective of the master tape is to provide a common data base which can be used by the research community to test theories, models, and methods for describing and analyzing control/display relations and interactions. The experimental conditions and tasks used to obtain the data and the detailed format of the tapes are described. Conventional instrument panel and controls were used, with simulated vertical gust and glide slope beam bend forcing functions. Continuous pilot eye fixations and scan traffic on the panel were measured. Both flight director and standard localizer/glide slope types of approaches were made, with both fixed and variable instrument range sensitivities.

Klein, R.↗
NASA NTRS1969

The relationship of NASA occupational medicine and environmental health with the Advisory Center on Toxicology

Preventive measures of occupational medicine and industrial hygiene are coordinated to identify toxicities of industrial products and safety standards in manned space flight applications. Emphasized is the off-gassing of construction materials in spacecraft with the resulting contamination of the cabin atmosphere and the establishment of criteria for the quality of drinking water for astronauts during Gemini and Apollo programs.

Wands, R. C.↗