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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 973 records · Page 54

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NASA NTRS1977

Formation of fatty acids in photochemical conversions of saturated hydrocarbons

Abiogenic synthesis of fatty acids was studied in photochemical conversions of saturated hydrocarbons. It was shown that, in a hydrocarbon water CaCO3 suspension, the action of 254 nm UV rays caused the formation of fatty acids with a maximum number of carbon atoms in the chain not exceeding that in the initial hydrocarbon. Synthesis of acetic, propionic, butyric, valeric, caproic, enanthic and caprylic (in the case of octane) acids occurs in heptane water CaCO3 and octane water CaCO3 systems.

Telegina, T. A.↗

NASA NTRS1977

Studies of orbital Eoetvoes experiments

A direct force-balance technique was analyzed for carrying out the Eoetvoes experiment in space, which is intended to give sufficient sensitivity to allow investigation of the gravitational interactions of energy stored in the weak interaction. The heart of experiment is an exceedingly sensitive dual accelerometer, containing two proof masses constructed of the materials whose Eoetvoes ratio is to be compared. For use in development of the accelerometer, a magnetic microbalance is proposed in which the weight of the proof mass is supported by magnetic forces which vary very slowly with the proof mass position. It is shown that at least two different mechanizations of the magnetic suspension may be feasible.

Chapman, P. K.↗

NASA NTRS1977

Design definition of a mechanical capacitor

A design study and analyses of a 10 kW-hr, 15 kW mechanical capacitor system was studied. It was determined that magnetically supported wheels constructed of advanced composites have the potential for high energy density and high power density. Structural concepts are analyzed that yield the highest energy density of any structural design yet reported. Particular attention was paid to the problem of 'friction' caused by magnetic and I to the second power R losses in the suspension and motor-generator subsystems, and low design friction levels have been achieved. The potentially long shelf life of this system, and the absence of wearing parts, provide superior performance over conventional flywheels supported with mechanical bearings. Costs and economies of energy storage wheels were reviewed briefly.

Michaelis, T. D.↗

NASA NTRS1976

The surface of Mars - The view from the Viking 2 lander

Viking 2 lander began imaging the surface of Mars at Utopia Planitia on September 3, 1976. The surface is a boulder-strewn reddish desert cut by troughs that probably form a polygonal network. A plateau can be seen to the east of the spacecraft, which for the most probable lander location is approximately the dirction of a tongue of ejecta from the crater Mie. Boulders at the lander 2 site are generally more vesicular than those near lander 1. Fines at both lander sites appear to be very fine-grained and to be bound in a duricrust. The pinkish color of the sky, similar to that observed at the lander 1 site, indicates suspension of surface material. However, the atmospheric optical depth is less than that at the lander 1 site. After dissipation of a cloud of dust stirred during landing, no changes other than those stemming from sampling activities have been detected in the landscape. No signs of large organisms are apparent at either landing site.

Mutch, T. A.↗

NASA NTRS1976

Clays as possible catalysts for peptide formation in the prebiotic era

From the point of view of prebiotic synthesis, clays might have performed functions of concentration, catalysis, and protection of molecules. The degrees of polymerization obtained, when amino acid adenylates are added to montmorillonite suspensions in water, are much higher than those obtained by polymerization in the absence of such a clay. In addition, they are of a discrete spectrum, usually multiples of 6 or 7, and reach values of up to 40 mers. In the absence of clay a continuous spectrum of degrees of polymerization is obtained, and usually up to 4-6 mers only. Copolymerization in the absence of clays yields mostly random copolymers, in their presence mostly block copolymers are obtained. Optical density measurements show that after adsorption has taken place on the clay, stacking of its layers occurs. Polymerization starts only after these stacked layers have been formed

Paecht-Horowitz, M.↗

NASA NTRS1976

Photometric studies of light scattering above the lunar terminator from Apollo solar corona photography

Excess brightness is found in 70-mm photographs of the solar corona above the lunar terminator during Apollo 15 and 17. Maximum brightness of this scattered light is determined from calibration of image density. The observed excess brightness displays circular symmetry above the lunar-horizon subsolar point, characteristic of forward diffraction scattering from micron or submicron size (solid) grains, and decays rapidly in intensity with altitude and distance from the lunar terminator. The observed brightness cannot be accounted for by a co-orbiting cloud of spacecraft contaminants, but requires a variable lunar dust 'atmosphere' over the terminator regions extending to altitudes in excess of 100 km. To maintain such large masses of lunar fines above the terminator requires either local mass-churning rates in excess of 2 by 10 to the -11th power g/sq cm sec or the assumption of some degree of high-altitude electrostatic suspension to increase the dwell time of individual grains at the altitudes observed. Such a model would reduce mass-churning rates while causing selective erosion/deposition and potential for escape of significant mass from the moon

Mccoy, J. E.↗

NASA NTRS1977

Light energy conservation processes in Halobacterium halobium cells

Proton pumping driven by light or by respiration generates an electrochemical potential difference across the membrane in Halobacterium halobium. The pH changes induced by light or by respiration in cell suspensions are complicated by proton flows associated with the functioning of the cellular energy transducers. A proton-per-ATP ratio of about 3 is calculated from simultaneous measurements of phosphorylation and the proton inflow. This value is compatible with the chemiosmotic coupling hypothesis. The time course of the light-induced changes in membrane potential indicates that light-driven pumping increases a dark pre-existing potential of about 130 mV only by a small amount (20 to 30 mV). The complex kinetic features of the membrane potential changes do not closely follow those of the pH changes, which suggests that flows of ions other than protons are involved. A qualitative model consistent with the available data is presented.

Bogomolni, R. A.↗

NASA NTRS1977

Flywheel energy storage. II - Magnetically suspended superflywheel

This article, the second of a two part paper, describes the general design requirements for a flywheel energy storage system. A new superflywheel energy storage system, using a spokeless, magnetically suspended, composite material pierced disk rotor is proposed. The new system is configured around a permanent magnet ('flux biased') magnetic suspension system with active control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of stationary armature coils is proposed. There is no mechanical contact with the rotating ring and long life and low run down losses are projected. A discussion of major components for a 10 kwh system is presented.

Kirk, J. A.↗

NASA NTRS1976

Surface crystalline carbon temperature sensor

The described sensor has been used to measure small temperature changes in investigations related to the study of the properties of superfluid helium under zero-gravity conditions. The sensor requirements included high sensitivity, rapid response, small size, reproducibility, and ease of application to a test surface. In the preparation of the sensor a thin film of a commercially available carbon colloidal suspension is deposited on a substrate which must be electrically insulated or be covered with an insulating layer.

Petrac, D.↗

NASA NTRS1977

A practical magnetic bearing

A small compact magnetic bearing design developed and tested features a bearing capable of supporting over ten times its own weight, dimensioned 8 cm diam by 3.75 cm, with rare-earth cobalt magnets. Only 1% of the device payload figures as part of the magnetic suspension. The design is servoed in two axes and exhibits inherent stability in three more degrees of freedom, with full rotational freedom in the desired axis. Capacitive radial gap sensing allows stiff servoing of the rotation axis. Differential sensing and EM control linearize control functions. Low power drain, simple fabrication and assembly, and larger clearances than in air bearings or ball bearings are reported

Studer, P. A.↗

NASA NTRS1979

Improved nucleonic coal-thickness monitor

Design for coal-thickness-sensing instrument features independent hydropneumatic suspension of radiation source and detector. Monitor uses source and detector which are independently mounted, to follow contour of coal surface more closely and to eliminate errors caused by variations in airgap along radiation path. Device may help to bring fully-automated coal mining closer to reality.

Crouch, C. E.↗

NASA NTRS1977

Spin-tunnel investigation of the spinning characteristics of typical single-engine general aviation airplane designs. 2: Low-wing model A; tail parachute diameter and canopy distance for emergency spin recovery

A spin tunnel study is reported on a scale model of a research airplane typical of low-wing, single-engine, light general aviation airplanes to determine the tail parachute diameter and canopy distance (riser length plus suspension-line length) required for energency spin recovery. Nine tail configurations were tested, resulting in a wide range of developed spin conditions, including steep spins and flat spins. The results indicate that the full-scale parachute diameter required for satisfactory recovery from the most critical conditions investigated is about 3.2 m and that the canopy distance, which was found to be critical for flat spins, should be between 4.6 and 6.1 m.

Burk, S. M., Jr.↗

NASA NTRS1978

A Multi-Band Far-Infrared Survey with a Balloon-Borne Telescope

Nine additional radiation sources, above a 3-sigma confidence level of 1300 Jy, were identified at 100 microns by far infrared photometry of the galactic plane using a 0.4 meter aperture, liquid helium cooled, multichannel far infrared balloon-borne telescope. The instrument is described, including its electronics, pointing and suspension systems, and ground support equipment. Testing procedures and flight staging are discussed along with the reduction and analysis of the data acquired. The history of infrared astronomy is reviewed. General infrared techniques and the concerns of balloon astronomers are explored.

Jacobson, M. R.↗

NASA NTRS1978

Shuttle being tested at Marshall Center

Ground vibration tests of the space shuttle vehicle performed to evaluate the structural dynamics and their effect on the control system of the shuttle are described. Test results are used to verify the system design and mathematical models that predict how the shuttle's control system will react to the much more severe vibrations expected during launch and flight into orbit. The test configurations, the test facility, and the dynamic test suspension system are among the topics discussed.

Source record↗

NASA NTRS1978

Water system microbial check valve development

Development work on a device for the Space Shuttle that will prevent the transfer of viable microorganisms within water systems is described. The device serves as a check valve in that it prevents the transfer or cross-contamination of microorganisms from a nonpotable system into a potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the air gap found in conventional one gravity systems. The device is essentially a bed of resin material impregnated with iodine. Basic design data for a variety of flow and temperature conditions are presented, together with results of challenging the beds with suspensions of seven microorganisms including aerobes, anaerobes, and spore formers.

Colombo, G. V.↗

NASA NTRS1977

Mars Rover system loopwheel definition support

The feasibility of the loopwheel suspension system for use on a Mars roving vehicle was analyzed. Various steering concepts were evaluated and an optimum concept was identified on the basis of maximum probability of mission success. In the structural analysis of the loopwheel core and tread as the major fatigue critical components, important technology areas were identified.

Trautwein, W.↗

NASA NTRS1978

Preliminary measurements of quality factors of monocrystals

High Q's were obtained with silicon and sapphire crystals on four points mechanical suspensions. Instrumentation was developed to observe the approach to thermal equilibrium at cryogenic temperatures and to study thermal noise level and fluctuations. High Q crystals with low thermal noise level are promising candidates as high stability time references.

Richard, J. P.↗

NASA NTRS1978

Lateral forces induced by a misaligned roller

The magnitude of the lateral force induced by a roller, misaligned in its direction of travel is considered. Consequences of the induced lateral forces and examples of wheel suspension designs are given.

Mcginness, H.↗