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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Energy in the environment and the second law of thermodynamics

The relationship between the consumption of energy by technological cultures and the second law of thermodynamics is discussed. The analysis is based on a description of the operation of a mechanical device which consumes energy. It is concluded that the flow of energy in manifold spontaneous conditions, which play a vital role in the operation of any technological process, remove most of the energy flow path from the control of the operator. It is stated that the increased efficiency of a process can benefit the environment only as much as this efficiency enables the total energy input to be reduced for a given level of production and increasing efficiency cannot meet the problems of an increased rate of energy utilization.

Mueller, R. F.↗
NASA NTRS1972

Latitude and local time dependence of precipitated low energy electrons at high latitudes

Data from particle detectors on board the satellite OGO-4 were used to study the precipitation of electrons in the energy range 0.7 to 24 keV. The latitude dependence of these particles in the local time region from midnight to dawn was investigated in detail. The analysis shows that the precipitation of particles of energies 2.3 to 24 keV is centered at an invariant latitude of about 68 deg at midnight with a clear shift in latitude with increasing local time and this shift is more pronounced for lower energies. The highest fluxes of particles in this energy interval are measured at midnight and they decrease rapidly with local time. The data in the energy range 2.3 to 24 keV support a theory where particles are injected in the midnight region from the tail gaining energy due to a betatron process and then drift eastwards in a combined electric and magnetic field. The main part of the electrons at 0.7 keV show a different behavior. They seem to undergo an acceleration process which is rather local, sometimes giving field aligned fluxes which may be super-imposed on the background precipitation.

Gustafsson, G.↗
NASA NTRS1971

The fracture energy and some mechanical properties of a polyurethane elastomer.

The energy required to form a unit of new surface in the fracture of a polyurethane elastomer is determined. The rate sensitivity of the material has been reduced by swelling it in toluene. This paper primarily describes the experimental work of measuring the lower limit of the fracture energy. With this value and the creep compliance as a basis, the rate dependence of fracture energy for the unswollen material has been determined. It is thus shown that the dependence of the fracture energy on the rate of crack propagation can be explained by energy dissipation around the tip of the crack. Good agreement between the theoretically and experimentally determined relationships for the rate-sensitive fracture energy is demonstrated.

Mueller, H. K.↗
NASA NTRS1972

Measurements of electron-bremsstrahlung coincidence rates at intermediate electron energies

Coincidence rates have been measured for inelastically scattered electrons and their associated bremsstrahlung for bombarding energies of 0.20 and 0.15 MeV. Measurements were made for an electron angle of 45 deg and a photon angle of 20 deg. Inelastic electron energies of 0.15 and 0.16 MeV were considered for an incident energy of 0.2 MeV and an inelastic electron energy of 0.12 MeV was considered for an incident energy of 0.15 MeV. To observe the trend with atomic number, Al and Au targets were used. The experimental cross section differentials in photon and electron angles and energy were found to be smaller than the predictions of the Bethe-Heitler theory.

Rester, D. H.↗
NASA NTRS1973

Low-energy electron experiment for Atmosphere Explorer-C and -D.

The low-energy electron experiment will provide differential measurements of the energy influx and angular distributions of electrons and protons on the Atmosphere Explorer-C and -D missions. The detectors consist of cylindrical electrostatic analyzers for species and energy selection and Spiraltron electron multipliers as particle sensors. The C version will contain three detectors, two measuring electrons and protons from 0.2 to 25 keV in 16 logarithmically spaced steps and one measuring 5 keV electrons continuously. Angular distributions will be acquired utilizing the spin of the spacecraft. The D version will contain 19 detectors, one proton-stepped energy analyzer, and two electron-stepped energy analyzers at two different angles, again over the energy range 0.2 to 25 keV.

Hoffman, R. A.↗
NASA NTRS1973

The activation energy for creep of columbium /niobium/.

The activation energy for creep of nominally pure columbium (niobium) was determined in the temperature range from 0.4 to 0.75 T sub M by measuring strain rate changes induced by temperature shifts at constant stress. A peak in the activation energy vs temperature curve was found with a maximum value of 160 kcal/mole. A pretest heat treatment of 3000 F for 30 min resulted in even higher values of activation energy (greater than 600 kcal/mole) in this temperature range. The activation energy for the heat-treated columbium (Nb) could not be determined near 0.5 T sub M because of unusual creep curves involving negligible steady-state creep rates and failure at less than 5% creep strain. It is suggested that the anomalous activation energy values and the unusual creep behavior in this temperature range are caused by dynamic strain aging involving substitutional atom impurities and that this type of strain aging may be in part responsible for the scatter in previously reported values of activation energy for creep of columbium (Nb) near 0.5 T sub M.

Klein, M. J.↗
NASA NTRS1973

Energy and resource consumption

The present and projected energy requirements for the United States are discussed. The energy consumption and demand sectors are divided into the categories: residential and commercial, transportation, and industrial and electrical generation (utilities). All sectors except electrical generation use varying amounts of fossile fuel resources for non-energy purposes. The highest percentage of non-energy use by sector is industrial with 71.3 percent. The household and commercial sector uses 28.4 percent, and transportation about 0.3 percent. Graphs are developed to project fossil fuel demands for non-energy purposes and the perdentage of the total fossil fuel used for non-energy needs.

Source record↗
NASA NTRS1973

OGO-6 gas-surface energy transfer experiment

The kinetic energy flux of the upper atmosphere was analyzed using OGO-6 data. Energy transfer between 10 microwatts/sq cm and 0.1 W/sq cm was measured by short-term frequency changes of temperature-sensitive quartz crystals used in the energy transfer probe. The condition of the surfaces was continuously monitored by a quartz crystal microbalance to determine the effect surface contamination had on energy accommodation. Results are given on the computer analysis and laboratory tests performed to optimize the operation of the energy transfer probe. Data are also given on the bombardment of OGO-6 surfaces by high energy particles. The thermoelectrically-cooled quartz crystal microbalance is described in terms of its development and applications.

Mckeown, D.↗
NASA NTRS1974

Air transportation - Energy cost-effective or not

Current technology aircraft have energy intensities comparable to ground transport modes. Operational changes can further improve their relative energy performance. Wide-body aircraft have already significantly improved fleet energy intensity and will continue to do so as they become more predominant. This is reflected in the 1972 fleet-wide energy intensity data which show both the domestic and international carriers at the lowest jet aircraft intensity levels ever attained. Technological improvements decreased the energy requirements of wide-body aircraft while also significantly reducing aircraft noise and pollution emission levels. Load factor is the most significant parameter affecting existing aircraft energy intensity and therefore should be raised. Fuel scarcity is now forcing such a change.

Maddalon, D. V.↗
NASA NTRS1974

Transportation vehicle energy intensities. A joint DOT/NASA reference paper

A compilation of data on the energy consumption of air and ground vehicles is presented. The ratio BTU/ASM, British Thermal Units/Available Seat Mile, is used to express vehicle energy intensiveness, and related to the energy consumed directly in producing seat-mile or ton-mile productivity. Data is presented on passenger and freight vehicles which are in current use or which are about to enter service, and advanced vehicles which may be operational in the 1980's and beyond. For the advanced vehicles, an estimate is given of the date of initial operational service, and the performance characteristics. Other key considerations in interpreting energy intensiveness for a given mode are discussed, such as: load factors, operations, overhead energy consumption, and energy investments in new structure and equipment.

Mascy, A. C.↗
NASA NTRS1975

Significance of medium energy gamma ray astronomy in the study of cosmic rays

Medium energy (about 10 to 30 MeV) gamma ray astronomy provides information on the product of the galactic electron cosmic ray intensity and the galactic matter to which the electrons are dynamically coupled by the magnetic field. Because high energy (greater than 100 MeV) gamma ray astronomy provides analogous information for the nucleonic cosmic rays and the relevant matter, a comparison between high energy and medium energy gamma ray intensities provides a direct ratio of the cosmic ray electrons and nucleons throughout the galaxy. A calculation of gamma ray production by electron bremsstrahlung shows that: bremsstrahlung energy loss is probably not negligible over the lifetime of the electrons in the galaxy; and the approximate bremsstrahlung calculation often used previously overestimates the gamma ray intensity by about a factor of two. As a specific example, expected medium energy gamma ray intensities are calculated for the speral arm model.

Fichtel, C. E.↗
NASA NTRS1974

Wind energy developments in the 20th century

Wind turbine systems for generating electrical power have been tested in many countries. Representative examples of turbines which have produced from 100 to 1250 kW are described. The advantages of wind energy consist of its being a nondepleting, nonpolluting, and free fuel source. Its disadvantages relate to the variability of wind and the high installation cost per kilowatt of capacity of wind turbines when compared to other methods of electric-power generation. High fuel costs and potential resource scarcity have led to a five-year joint NASA-NSF program to study wind energy. The program will study wind energy conversion and storage systems with respect to cost effectiveness, and will attempt to estimate national wind-energy potential and develop techniques for generator site selection. The studies concern a small-systems (50-250 kW) project, a megawatt-systems (500-3000 kW) project, supporting research and technology, and energy storage. Preliminary economic analyses indicate that wind-energy conversion can be competitive in high-average-wind areas.

Vargo, D. J.↗
NASA NTRS1975

Analysis of liquid metal embrittlement from a bond energy viewpoint

Absorption induced embrittlement of solid metals by certain liquid metals is analyzed through an Engel-Brewer calculation of the solid-liquid interaction energy, and of the effect of the latter in reducing fracture surface energy. The reduction in fracture surface energy is estimated by comparison of the electronic contribution to the solid-liquid interaction energy with solid-solid bond energy for some 40 liquid-solid couples. Regular solution theory is used to estimate mutual solubility as the relative difference in parameter values. Embrittlement can be predicted by using reduction in fracture surface energy and solubility parameter difference as critical variables. The effect of solute additions to the liquid on the degree of embrittlement is interpreted via the same two variables; the principal effect of solutes is to modify solubility relationships at the solid-liquid interface.

Kelley, M. J.↗
NASA NTRS1975

A new wind energy conversion system

It is presupposed that vertical axis wind energy machines will be superior to horizontal axis machines on a power output/cost basis and the design of a new wind energy machine is presented. The design employs conical cones with sharp lips and smooth surfaces to promote maximum drag and minimize skin friction. The cones are mounted on a vertical axis in such a way as to assist torque development. Storing wind energy as compressed air is thought to be optimal and reasons are: (1) the efficiency of compression is fairly high compared to the conversion of mechanical energy to electrical energy in storage batteries; (2) the release of stored energy through an air motor has high efficiency; and (3) design, construction, and maintenance of an all-mechanical system is usually simpler than for a mechanical to electrical conversion system.

Smetana, F. O.↗
NASA NTRS1976

Investigation of storage system designs and techniques for optimizing energy conservation in integrated utility systems. Volume 1: (Executive summary)

Integrated Utility Systems (IUS) have been suggested as a means of reducing the cost and conserving the nonrenewable energy resources required to supply utility services (energy, water, and waste disposal) to developments of limited size. The potential for further improving the performance and reducing the cost of IUS installations through the use of energy storage devices is examined and the results are summarized. Candidate energy storage concepts in the general areas of thermal, inertial, superconducting magnetic, electrochemical, chemical, and compressed air energy storage are assessed and the storage of thermal energy as the sensible heat of water is selected as the primary candidate for near term application to IUS.

Source record↗
NASA NTRS1976

On the question of the energy of the precessional dynamo

The various estimates for the coupling mechanism by which precession transfers rotational, kinetic energy of earth into the energy of its magnetic field are generally considering hydromagnetic stresses that originate between mantle and core. Estimates of the energy of the geomagnetic field calculated from the data of spherical harmonic analysis derive precession energy values in reasonable agreement with the observed external energy of the geomagnetic field and with the rate of ohmic dissipation of energy in the core.

Dolginov, S. S.↗
NASA NTRS1976

Significance of medium-energy gamma-ray astronomy in the study of cosmic rays

The paper examines the medium-energy (about 10-30 MeV) galactic gamma-ray radiation from primary and secondary electrons and calculates the expected gamma-ray distribution for the specific model of Bignami et al. (1975) on the assumption that the cosmic rays are correlated with the matter on the scale of galactic arms. The energy spectrum typical of regions near the galactic center indicates a dramatic shift from a predominantly cosmic-ray nucleonic mechanism at higher energies to a cosmic-ray electron mechanism at the lower energies. This provides a most important and direct means of probing the cosmic-ray electrons as a function of galactic position by making gamma-ray observations in the few to 40 MeV energy range. Medium-energy gamma-ray astronomy is shown to be a valuable tool in galactic research.

Fichtel, C. E.↗
NASA NTRS1976

Vibration-translation energy transfer in vibrationally excited diatomic molecules

A semiclassical collision model is applied to the study of energy transfer rates between a vibrationally excited diatomic molecule and a structureless atom. The molecule is modeled as an anharmonic oscillator with a multitude of dynamically coupled vibrational states. Three main aspects in the prediction of vibrational energy transfer rates are considered. The applicability of the semiclassical model to an anharmonic oscillator is first evaluated for collinear encounters. Second, the collinear semiclassical model is applied to obtain numerical predictions of the vibrational energy transfer rate dependence on the initial vibrational state quantum number. Thermally averaged vibration-translation rate coefficients are predicted and compared with CO-He experimental values for both ground and excited initial states. The numerical model is also used as a basis for evaluating several less complete but analytic models. Third, the role of rational motion in the dynamics of vibrational energy transfer is examined. A three-dimensional semiclassical collision model is constructed with coupled rotational motion included. Energy transfer within the molecule is shown to be dominated by vibration-rotation transitions with small changes in angular momentum. The rates of vibrational energy transfer in molecules with rational frequencies that are very small in comparison to their vibrational frequency are shown to be adequately treated by the preceding collinear models.

Mckenzie, R. L.↗