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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1970

Rugged, low-conductance, heat-flow probe

Lightweight, compact probe structure has low thermal conductance to enable accurate measurement of slight temperature gradients. Probe combines ruggedness, high precision, accuracy, and stability. Device can withstand vibration, shock, acceleration, temperature extremes, and high vacuums, and should interest industrial engineers and geologists.

Boudreau, E. J.↗
NASA NTRS1981

A pumped, two-phase flow heat transport system for orbiting instrument payloads

A pumped two-phase (heat absorption/heat rejection) thermal transport system for orbiting instrument payloads is investigated. The thermofluid characteristics necessary for the system design are discussed. A preliminary design with a series arrangement of four instrument heat stations and six radiators in a single loop is described in detail, and the total mass is estimated to be 134 kg, with the radiators, instrument heat stations, and fluid reservoir accounting for approximately 86, 24, and 12 kg, respectively. The evaluation of preliminary test results shows that the system has potential advantages; however, further research is necessary in the areas of one-g and zero-g heat transfer coefficients/fluid regimes, fluid by-pass temperature control, and reliability of small pumps.

Fowle, A. A.↗
NASA NTRS1988

Tidal dissipation, surface heat flow, and figure of viscoelastic models of Io

The deformation of Io, the tidal dissipation rate, and its interior spatial distribution are investigated by means of numerical simulations based on (1) a three-layer model (with dissipation in the mantle) or (2) a four-layer model (with dissipation in the asthenosphere). The mathematical derivation of the models is outlined; the selection of the input-parameter values is explained; the results are presented in extensive graphs and contour maps; and the constraints imposed on the models by observational data on the hot-spot distribution, tidal deformation, and gravity field are discussed in detail. It is found that both dissipation mechanisms may play a role on Io: model (2) is better able to explain the concentration of hot spots near the equator, while the presence of a large hot spot near the south pole (if confirmed by observations) would favor model (1).

Segatz, M.↗
NASA NTRS1986

Heat flow control and segregation in directional solidification: Development of an experimental and theoretical basis for Bridgman-type growth experiments in a microgravity environment

Within the framework of the proposed research, emphasis was placed on application of magnetic fields to semiconductor growth systems. It was found that magnetic fields up to 3 kGauss do not affect the growth behavior nor the macro-segregation behavior in the system Ge(Ga). Applied fields are found to significantlty alter the radial dopant distribution, which is attributed to alterations in the spatial orientation of convective cells. Increasing the magnetic field to 30 kGauss is found to have a fundamental effect on dopant segregation. Emphasis is also placed on the potential of KC-135 flights for preliminary studies on the effects of reduced gravity environments on the wetting behavior of semiconductor systems in growth configuration. The limited number of experiments conducted does not allow any conclusions on the merits of KC-135 flights for semiconductor processing research.

Witt, A. F.↗
NASA NTRS1988

Heat Flow and Magnetization in the Oceanic Lithosphere

Two aspects of the processing and interpretation of satellite measurements of the geomagnetic field are described. One deals with the extraction of the part of the geomagnetic field that originates from sources in the earth's atmosphere. The other investigates the possibility of using the thermal state of the oceanic lithosphere to further constrain modelling and interpretation of magnetic anomalies. It is shown that some of the magnetic signal in crustal anomaly maps can be an artifact of the mathematical algorithms that have been used to separate the crustal field from the observed data. Strong magnetic anomalies can be distorted but are probably real, but weak magnetic anomalies can arise from leakage of power from short wavelengths, and will also appear in anomaly maps as repetitions of the strong crustal anomaly. The distortion and the ghost anomalies follow the magnetic dip lines in a way that is similar to actual MAGSAT anomaly fields. This phenomenon will also affect the lower degree spherical harmonic terms in the power spectrum of the crustal field. A model of the magnetic properties of the oceanic crust that has been derived from direct measurements of the rock magnetic properties of oceanic rocks is presented. The average intensity of magnetization in the oceanic crust is not strong enough to explain magnetic anomalies observed over oceanic areas. This is the case for both near surface observations (ship and aeromagnetic data) and satellite altitude observations. It is shown that magnetic sources in the part of the upper mantle that is situated above the Curie isotherm, if sufficiently strong, can produce satellite magnetic anomalies that are comparable to MAGSAT data. The method developed for the study of depth to the Curie isotherm and magnetic anomalies can also be used in inverse modelling of satellite magnetic anomalies when the model is to be adjusted with an annihilator.

Hayling, Kjell Lennart↗
NASA NTRS1990

Lithospheric flexure beneath the Freyja Montes foredeep, Venus - Constraints on lithospheric thermal gradient and heat flow

Analysis of Venera 15 and 16 radar images and topographic data from the Freyja Montes region on Venus suggests that this mountain belt formed as a result of a sequence of underthrusts of the lithosphere of the North Polar Plains beneath the highlands of Ishtar Terra. The lithospheric flexure hypothesis is tested, and the effective thickness Te of the elastic lithosphere of the underthrusting portion of the North Polar Plains is estimated by fitting individual topographic profiles to deflection curves for a broken elastic plate. The theoretical curves fit the observed topographic profiles to within measurement error for values of flexural rigidity D in the range (0.8-3) x 10 to the 22nd N m, equivalent to Te in the range 11-18 km.

Solomon, Sean C.↗
NASA NTRS1992

Visoelastic relaxation of Venusian coronae and mountain belts: Constraints on global heat flow and tectonism

Venus differs from Earth in that water is essentially absent and its surface temperatures are about 470 K higher. The competing effects of high surface temperature and dry lithologies on the long-term history of surface topography have been studied using the finite-element method. The relaxation history of surface topographic features, such as coronae and mountain belts, is a function of thermal gradient, crustal thickness and lithology, regional stresses, and basal tractions applied to the lithosphere. In this study, we have examined the relative effects of these factors over a period of 500 Ma (presumed to be the mean age of the venusian surface).

Duncan, I.↗
NASA NTRS2001

Io: Heat Flow and Surface Age

Assuming Io is completely resurfaced with volcanics, ages to surface units on Io can be assigned as a function of temperature. Additional information is contained in the original extended abstract.

Matson, D. L.↗