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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Liquid rocket actuators and operators

All the types of actuators and associated operators used in booster, upper stage, and spacecraft propulsion and reaction-control systems except for chemical-explosive actuators and turbine actuators are discussed. Discussion of static and dynamic seals, mechanical transmission of motion, and instrumentation is included to the extent that actuator or operator design is affected. Selection of the optimum actuator configuration is discussed for specific application which require a tradeoff study that considers all the relevant factors: available energy sources, load capacity, stroke, speed of response, leakage limitations, environmental conditions, chemical compatibility, storage life and conditions, size, weight, and cost. These factors are interrelated with overall control-system design evaluations that are beyond the scope of this monograph; however, literature references are cited for a detailed review of the general considerations. Perinent advanced-state-of-the-art design concepts are surveyed briefly.

Source record↗
NASA NTRS1974

Data on incident solar energy

Instrumentation for solar irradiance monitoring, and radiation scales are discussed in a survey of incident solar energy data. The absolute accuracy and intrinsic reliability of the values of the solar constant and zero air mass solar spectrum proposed by the Institute of Environmental Sciences as an ASTM standard are evaluated. Extraterrestrial observations are used for deriving solar irradiance data at ground level for widely varying atmospheric parameters, with special reference to air pollution. The effects of diffuse sky radiance and those of varying slopes of the solar energy collecting surface are examined. Average values of solar energy available at different locations in the United States are included.

Thekaekara, M. P.↗
NASA NTRS1974

Centrifugal instability of the Jovian magnetosphere and its interaction with the solar wind

The outer regions (r greater than 2.3 Jupiter radii) of the magnetosphere of Jupiter will systematically accumulate plasma. If sufficient plasma accumulates, the field lines must open to allow the plasma to escape. Available energy sources appear able to supply plasma at a high enough rate to keep the field lines constantly open beyond about 60 Jupiter radii. It is suggested that the solar wind interaction with Jupiter may be essentially different from that with the earth, with the Jovian magnetosphere opening up to form a planetary wind.

Michel, F. C.↗
NASA NTRS1975

Analytical Applications of Bioluminescence and Chemiluminescence

Bioluminescence and chemiluminescence studies were used to measure the amount of adenosine triphosphate and therefore the amount of energy available. Firefly luciferase - luciferin enzyme system was emphasized. Photometer designs are also considered.

Chappelle, E. W.↗
NASA NTRS1975

On the oxygen and nitrogen enhancements observed in low energy cosmic rays

Fisk et al. (1974) have suggested that neutral particles are ionized in the solar cavity, are subsequently picked up by the solar wind, obtaining energies of about 1 keV/nucleon, and may be further accelerated to about 10 MeV/nucleon in the interplanetary medium. The requirements for this acceleration are examined, and a possible acceleration model is outlined. The acceleration must be performed in a time less than the dwell time of the interstellar ions in the solar cavity and must compete successfully against adiabatic cooling. The energy required for the acceleration must be less than the energy available in variations in the solar wind flow. The accelerator must act inefficiently on solar wind electrons and protons, and perhaps upon the majority of interstellar ions. It is shown that these requirements can be satisfied by a model in which acceleration results from transit-time damping of long-wavelength magnetosonic turbulence.

Fisk, L. A.↗
NASA NTRS1978

Inexpensive, portable, integrating solar energy meter

Silicon-cell insolometer automatically measures and totals amount of energy available in sunlight falling on the earth at specific location over selected period of time. Device incorporates single silicon solar cell as sensing element and relies on principle that short-circuit current from solar cell is directly proportional to amount of light that shines on cell.

Masters, R. M.↗
NASA NTRS1977

Solar energy meter

An instrument was developed to continually integrate the energy available in incident light on a specifically oriented surface. The unit was designed for outdoor use in remote locations and is capable of operation over a temperature range of -20 to +60 C with good accuracy. The unit is weather resistant, requires low power, has a high input impedance, is inexpensive, and has a visual readout and an analog output for recording.

Masters, R. M.↗
NASA NTRS1978

Frequency analysis of 4- to 6-keV electrons associated with an auroral arc

The high time resolution (HTR) experiment considered consists of four sections, including electrostatic deflection plates, electron multiplier, preamplifier-integrator, and frequency analyzer. Electrons in the energy range from 4 to 6 keV electrons are selected by the deflection system, after which they are detected, multiplied, and passed to the charge sensitive preamplifier. The charge pulses are amplified and integrated, and the resulting voltage pulse series is fed to the frequency analyzer. The experiment is essentially a flux detector, so that estimates of the input flux can be made from the mean value of the output spectrum. The results obtained with the HTR in a rocket flight on March 14, 1974, are discussed. The lack of modulation noticed in the high-frequency range indicates that there is insufficient wave energy available in the vicinity of the rocket to produce a wave-particle interaction which the HTR is able to observe. This finding is consistent with the stabilization of the plasma by the low flux of energetic electrons.

Murphree, J. S.↗
NASA NTRS1979

The design and testing of a memory metal actuated boom release mechanism

A boom latch and release mechanism was designed, manufactured and tested, based on a specification for the ISEE-B satellite mechanism. From experimental results obtained, it is possible to calculate the energy available and the operating torques which can be achieved from a torsional shape memory element in terms of the reversible strain induced by prior working. Some guidelines to be followed when designing mechanisms actuated by shape memory elements are included.

Powley, D. G.↗
NASA NTRS1978

Efficiency degradation due to tracking errors for point focusing solar collectors

An important parameter in the design of point focusing solar collectors is the intercept factor which is a measure of efficiency and of energy available for use in the receiver. Using statistical methods, an expression of the expected value of the intercept factor is derived for various configurations and control law implementations. The analysis assumes that a radially symmetric flux distribution (not necessarily Gaussian) is generated at the focal plane due to the sun's finite image and various reflector errors. The time-varying tracking errors are assumed to be uniformly distributed within the threshold limits and allows the expected value calculation.

Hughes, R. O.↗
NASA NTRS1980

An electric vehicle propulsion system's impact on battery performance: An overview

The performance of two types of batteries, lead-acid and nickel-zinc, was measured as a function of the charging and discharging demands anticipated from electric vehicle propulsion systems. The benefits of rapid high current charging were mixed: although it allowed quick charges, the energy efficiency was reduced. For low power (overnight) charging the current wave shapes delivered by the charger to the battery tended to have no effect on the battery cycle life. The use of chopper speed controllers with series traction motors resulted in a significant reduction in the energy available from a battery whenever the motor operates at part load. The demand placed on a battery by an electric vehicle propulsion system containing electrical regenerative braking confirmed significant improvment in short term performance of the battery.

Bozek, J. M.↗
NASA NTRS1979

Explicit large time-step schemes for the shallow water equations

Modifications to explicit finite difference schemes for solving the shallow water equations for meteorological applications by increasing the time step for the fast gravity waves are analyzed. Terms associated with the gravity waves in the shallow water equations are treated on a coarser grid than those associated with the slow Rossby waves, which contain much more of the available energy and must be treated with higher accuracy, enabling a several-fold increase in time step without degrading the accuracy of the solution. The method is presented in Cartesian and spherical coordinates for a rotating earth, using generalized leapfrog, frozen coefficient, and Fourier filtering finite difference schemes. Computational results verify the numerical stability of the approach.

Turkel, E.↗
NASA NTRS1980

Effect of blackbody radiation on the threshold for two-electron photodetachment of H/-/

The threshold law of the titled process, which is of the same form as that for electron-impact ionization of H, can experimentally be contaminated by simultaneous single photodetachment and Rydberg excitation of the residual atom, followed by ionization of the Rydberg atom by (room-temperature) blackbody photons. This gives a signal indistinguishable from direct double photodetachment. The correction is here calculated and shown to be finite at the double photodetachment threshold, and to have, possibly, an implication about the form of the threshold law itself. However, at room temperature its contribution is found to be small as it pertains to a recently initiated experiment at the Los Alamos Meson Physics Facility for available energies greater than a millivolt above threshold. The temperature dependence of the correction is shown to be large (k/B/T) to the 7/2; thus at higher temperatures the effect may be observable.

Temkin, A.↗
NASA NTRS1981

A Fresnel collector process heat experiment at Capitol Concrete Products

An experiment is planned, conducted and evaluated to determine the feasibility of using a Power Kinetics' Fresnel concentrator to provide process heat in an industrial environment. The plant provides process steam at 50 to 60 psig to two autoclaves for curing masonry blocks. When steam is not required, the plant preheats hot water for later use. A second system is installed at the Jet Propulsion Laboratory parabolic dish test site for hardware validation and experiment control. Experiment design allows for the extrapolation of results to varying demands for steam and hot water, and includes a consideration of some socio-technical factors such as the impact on production scheduling of diurnal variations in energy availability.

Hauger, J. S.↗
NASA NTRS1981

Simultaneous X-ray and optical observations of an Ursae Majoris during a low state

In November 1975, AN UMa was detected as a soft X-ray source with a 0.1-0.4 keV flux which was modulated with the orbital cycle. In order to investigate further this orbital dependence and to correlate it with existing photometric and spectroscopic observations to aid in determining the geometry of the system, simultaneous X-ray and optical observations were made throughout several cycles of AN UMa. The system was in a low optical state during the observations. The X-ray observations were made with the Imaging Proportional Counter on the Einstein Observatory, yielding measurements over an available energy range of 0.1-4 keV. Attention is given to total X-ray flux, the X-ray light curve, optical and infrared data, and model implications.

Szkody, P.↗
NASA NTRS1981

The Conference on High Temperature Electronics

The status of and directions for high temperature electronics research and development were evaluated. Major objectives were to (1) identify common user needs; (2) put into perspective the directions for future work; and (3) address the problem of bringing to practical fruition the results of these efforts. More than half of the presentations dealt with materials and devices, rather than circuits and systems. Conference session titles and an example of a paper presented in each session are (1) User requirements: High temperature electronics applications in space explorations; (2) Devices: Passive components for high temperature operation; (3) Circuits and systems: Process characteristics and design methods for a 300 degree QUAD or AMP; and (4) Packaging: Presently available energy supply for high temperature environment.

Hamilton, D. J.↗
NASA NTRS1982

The nature of large-scale turbulence in the Jovian atmosphere

The energetics and spectral characteristis of quasi-geostrophic turbulence in Jupiter's atmosphere are examined using sequences of Voyager images and infrared temperature soundings. Using global wind measurements momentum transports associated with zonally symmetric stresses and turbulent stresses are quantified. Though a strong up-gradient flux of momentum by eddies was observed, measurements do not preclude the possibility that symmetric stresses play a critical role in maintaining the mean zonal circulation. Strong correlation between the observed meridional distribution of eddy-scale kinetic energy and available potential energy suggests coupling between the observed cloudtop turbulent motions and the upper tropospheric thermodynamics. An Oort energy budget for Jupiter's upper troposphere is formulated.

Mitchell, J. L.↗
NASA NTRS1982

A further study of spectral energetics in the winter atmosphere

The contributions of standing (time-mean) and transient (time-departure) waves to the atmospheric spectral energetics are analyzed using the NMC (National Meteorological Center) data of winter 1976-1977. It is found that the standing long waves are responsible for the major horizontal sensible heat transport and also for the significant horizontal momentum transport. Furthermore, the major contents of eddy available energy and eddy kinetic energy of standing waves are in the long-wave regime. However, the spectral energetics analysis indicates that the standing long waves are energetically less efficient than the transient long and short waves. It is suggested that the lower efficiency of the standing long waves in the atmospheric energetics may be one of the physical factors causing the underforecast of the standing long waves in the numerical weather prediction models.

Chen, T.-C.↗