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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Variable resistance constant tension and lubrication device

A variable resistance device is described which includes a cylindrical housing having elongated resistance wires. A movable arm having a supporting block carried on the outer end is rotatably carried by the cylindrical housing. An arcuate steel spring member is pivotally supported by the movable arm. A leather wiper member is carried adjacent to one end of the spring steel member, and an electrically conductive surface is carried adjacent to the other end. The supporting block maintains the spring steel member in compression so that a constant pressure is applied to the conductive end of the spring steel member and the leather wiper. The leather wiper is saturated with a lubricating oil for maintaining the resistance wire clean as the movable arm is manipulated.

Smith, H. J.↗
NASA NTRS1975

Space vehicle

A space vehicle having an improved ascent configuration for use in traveling in space is presented. Components of the vehicle are: (1) a winged orbiter having an elongater fuselage and rearwardly directed main engines fixed to the fuselage; (2) an elongated tank assembly of an improved configuration disposed forwardly of the fuselage and connected with the main engines of the vehicle for supplying liquid propellants; and (3) a booster stage comprising a pair of integrated solid rocket boosters connected with the orbiter immediately beneath the fuselage and extended in substantial parallelism.

Vonpragenau, G. L.↗
NASA NTRS1975

Meter for use in detecting tension in straps having predetermined elastic characteristics

A meter for detecting tension in elastic bodies, especially in fabric straps employed as tie down straps for stowed objects is presented. The meter is characterized by a pair of elongated arms coupled together for pivotal motion about a common axis in a common plane and a strap receiver located at adjacent ends of the arms for receiving and securing adjacent portions of the strap. The receivers are supported by the arms for motion along intersecting arcs, and motion detection means is located at the opposite ends of the arms for detecting the magnitude of the motion imparted to the receivers as the strap is placed in tension.

Buhler, G. V.↗
NASA NTRS1975

Internally supported flexible duct joint

An internally supported, flexible duct joint for use in conducting fluids under relatively high pressures in systems where relatively large deflection angles must be accommodated is presented. The joint includes a flexible tubular bellows and an elongated base disposed within the bellows. The base is connected through radiating struts to the bellows near mid-portion and to each of the opposite end portions of the bellows through a pivotal connecting body. A motion-controlling linkage is provided for linking the connecting bodies, whereby angular displacement of the joint is controlled and uniformity in the instantaneous bend radius of the duct is achieved as deflection is imposed.

Kuhn, R. F., Jr.↗
NASA NTRS1975

The solar elogation distribution of low frequency radio bursts

Over 500 days of low frequency (less than 5 MHz) radio observations from the IMP-6 spacecraft were accumulated to produce a two dimensional map (frequency versus elongation) of solar type III burst occurrences. This map indicates that most solar bursts are emitted at the second harmonic of the plasma frequency rather than the fundamental. The map also shows that the solar wind electron density varies.

Kaiser, M. L.↗
NASA NTRS1974

Examination of the influence of coatings on thin superalloy sections. Volume 2: Detailed procedures and data

The effects of an aluminide coating, Codep B-1, and of section thickness were investigated on two cast nickel base superalloys, Rene 80 and Rene 120. Cast section thicknesses ranged from 0.038 cm to 0.15 cm. Simulated engine exposures for 1000 hours at 899C or 982C in a jet fuel burner rig with cyclic air cooling were studied, as were the effects of surface machining before coating and re-machining and re-coating after exposures. The properties evaluated included tensile at room temperature., 871C and 982C, stress rupture at 760C, 871C, 982C and 1093C, high cycle mechanical fatigue at room temperature., and thermal fatigue with a 1093C peak temperature. Thin sections had tensile strengths similar to standard size bars up to 871C and lower strengths at 982C and above, with equivalent elongation, and stress rupture life was lower for thin sections at all test conditions. The aluminide coating lowered tensile and rupture strengths up to 871C, with greater effects on thinner specimens. Elevated temperature exposure lowered tensile and rupture strengths of thinner specimens at the lower test temperatures. Surface machining had little effect on properties, but re-machining after exposure reduced thickness and increased metallurgical changes enough to lower properties at most test conditions.

Kaufman, M.↗
NASA NTRS1975

Device for use in loading tension members

The indicator is characterized by an elongated elastic body having extended from the opposite ends of threaded shanks adapted to selected tension members. A pair of external shoulders, one of which is axially displaceable relative to the other, and a rigid tubular sleeve interposed between said shoulders are included. Tension is applied to the elastic body for imparting strain. The movable shoulder can be advanced into abutting engagement with the sleeve, whereby the sleeve is placed in compression once the tensile forces are removed from the shanks. A reapplication of tensile forces equal to the initially applied tensile forces removes the sleeve from compression, whereby the sleeve is freed for rotation for thus indicating the magnitude of the applied tensile forces.

Appleberry, W. T.↗
NASA NTRS1975

Fractography of the high temperature hydrogen attack of a medium carbon steel

Microscopic fracture processes were studied which are associated with hydrogen attack of a medium carbon steel in a well-controlled, high-temperature, high-purity hydrogen environment. Exposure to a hydrogen pressure and temperature of 3.5 MN/m2 and 575 C was found to degrade room temperature tensile properties with increasing exposure time. After 408 hr, yield and ultimate strengths were reduced by more than 40 percent and elongation was reduced to less than 2 percent. Initial fissure formation was found to be associated with manganese rich particles, most probably manganese oxide, aligned in the microstructure during the rolling operation. Fissure growth was found to be associated with a reduction in carbide content of the microstructure and was inhibited by the depletion of carbon. The interior surfaces of sectioned fissures or bubbles exhibit both primary and secondary cracking by intergranular separation. The grain surfaces were rough and rounded, suggesting a diffusion-associated separation process. Specimens that failed at room temperature after exposure to hydrogen were found to exhibit mixed mode fracture having varying amounts of intergranular separation, dimple formation, and cleavage, depending on exposure time.

Melson, H. G.↗
NASA NTRS1975

Hole cutter

An adjustable hole cutter is described for use in forming circular openings in workpieces. The hole cutter is characterized by a mount of a substantially planar configuration, positionable into a plane paralleling the working plane of a selected workpiece. It also contains a shaft for imparting rotary motion to the mount about an axis of rotation normally related to the working plane, a plurality of stabilizing struts for resiliently supporting the mount in parallelism with the working plane as rotary motion is imparted thereto, a drill bit for drilling a pilot hole concentric with the axis of rotation, and an elongated cutting tool adjustably seated within a radially extended slot.

Thornton, G. E.↗
NASA NTRS1975

The source of the electric field in the nightside magnetosphere

In the open magnetosphere model magnetic field lines from the polar caps connect to the interplanetary magnetic field and conduct an electric field from interplanetary space to the polar ionosphere. By examining the magnetic flux involved it is concluded that only slightly more than half of the magnetic flux in the polar caps belongs to open field lines and that such field lines enter or leave the magnetosphere through narrow elongated windows stretching the tail. These window regions are identified with the tail's boundary region and shift their position with changes in the interplanetary magnetic field, in particular when a change of interplanetary magnetic sector occurs. The circuit providing electric current in the magnetopause and the plasma sheet is extended across those windows; thus energy is drained from the interplanetary electric field and an electric potential drop is produced across the plasma sheet. The polar cap receives its electric field from interplanetary space on the day side from open magnetic field lines and on the night side from closed field lines leading to the plasma sheet. The theory described provides improved understanding of magnetic flux bookkeeping, of the origin of Birkeland currents, and of the boundary layer of the geomagnetic tail.

Stern, D. P.↗
NASA NTRS1975

Thrust chamber life prediction. Volume 1: Mechanical and physical properties of high performance rocket nozzle materials

Pertinent mechanical and physical properties of six high conductivity metals were determined. The metals included Amzirc, NARloy Z, oxygen free pure copper, electroformed copper, fine silver, and electroformed nickel. Selection of these materials was based on their possible use in high performance reusable rocket nozzles. The typical room temperature properties determined for each material included tensile ultimate strength, tensile yield strength, elongation, reduction of area, modulus of elasticity, Poisson's ratio, density, specific heat, thermal conductivity, and coefficient of thermal expansion. Typical static tensile stress-strain curves, cyclic stress-strain curves, and low-cycle fatigue life curves are shown. Properties versus temperature are presented in graphical form for temperatures from 27.6K (-410 F) to 810.9K (1000 F).

Esposito, J. J.↗
NASA NTRS1975

Tensile properties of palladium-silver alloys with absorbed hydrogen

The alloys 90Pd-10Ag, 80Pd-20Ag, 70Pd-30Ag, 60Pd-40Ag, and 50Pd-50Ag containing absorbed hydrogen were tested in tension. The results show the tensile properties to be independent of the phase transition. Also, hydrogen in the lattice does not necessarily cause embrittlement or poor elongation. The changes in the tensile properties appear dependent on the electron to atom site ratio.

Smith, R. J.↗
NASA NTRS1974

Properties criteria for components and materials used in lightweight solar arrays

The present work describes the characteristics and design criteria for components and materials used in lightweight substrate solar arrays. This includes descriptions of wraparound-electrode solar cells, cell covers, and cell interconnects. Cell cover systems briefly discussed are fused silica, cerium stabilized glass, microsheet, FEP (tape, heat laminated, and spray on), and ESB 7070 glass integral covers. The majority of solar arrays orbited have used either silver, Kovar, copper, or molybdenum as interconnect metals. Data are presented comparing the Young's modulus E, ultimate tensile strength, coefficient of expansion, thermal conductivity, and percent elongation of these and other interconnect candidate materials. Guidelines for the use of end tab wraparound cells are listed.

Lott, D. R.↗
NASA NTRS1974

Metallurgical processing in space

Research in metallurgical processing to study the effects of reduced gravity started with Apollo 14 and advanced with Skylab. Experiments provided specimens for analysis which solidified while constrained and while freely floating, which contained a mixture of normally immiscible materials, demonstrated enhanced capillary flow, solubility and ordered growth of a directionally solidified eutectic. The smaller, equiaxed grain structure obtained in reduced gravity compared to the larger, elongated grains obtained in one gravity indicate a difference in convection due to gravity in constrained solidification. Freely floating nickel alloy specimens showing metallic gas evolution at low pressure and reduced gravity suggest reduced pressure reactions which cannot occur on earth even in high vacuum chambers due to the hydrostatic head in the molten metal. Directionally solidified eutectics showed fewer termination defects when grown in reduced gravity. These are a few of the differences observed due to reduced gravity which could have important consequences on the future of metallurgy. In this paper we attempt to correlate the results of several Skylab solidification experiments.

Mckannan, E. C.↗
NASA NTRS1975

Heat conduction in metal-filled polymers - The role of particle size, shape, and orientation

This paper presents a new type of analysis for predicting the thermal conductivity of disperse composites from the properties of the component phases and elementary characterizations of particle shapes and orientation. This analysis successfully predicted the sensitivity to particle shape which was confirmed by experiments also reported in this paper. These results suggest that highly elongated particles may be used to achieve dramatic modifications of thermal conductivity and the analysis presented here may be a useful tool in the design or development of disperse composites of specific thermal conductivity. The analysis may also apply to other properties such as electrical conductivity or magnetic permeability.

Hansen, D.↗
NASA NTRS1975

Solar radiation induced rotational bursting of interplanetary particles

It is suggested that the magnitudes of the two radiation-induced rotational bursting mechanisms (Radzieskii effect and windmill effect) have been overestimated and that they do not work significantly faster than the Poynting-Robertson effect in removing interplanetary particles. These two mechanisms are described, and serious doubts are raised regarding the derivation of their radiation pressure-torque proportionality constants, which are required for calculating their magnitudes. It is shown that both mechanisms will cause the alignment of elongated particles and, consequently, the polarization of zodiacal light. Since no positive polarization has been measured at the antisolar point, it is concluded that the magnitudes of the rotational bursting mechanisms are smaller than that of the Poynting-Robertson effect.

Sparrow, J. G.↗
NASA NTRS1975

Effects of convection electric field on the distribution of ring current type protons

The topology of the boundaries of penetration (or, inversely, the boundaries of the forbidden regions) of 90-deg pitch-angle equatorial protons with energies less than 100 keV are explored for an equatorial convection E-field which is directed in general from dawn to dusk. Due to the dependence of drift path on energy (or magnetic moment), complex structural features are expected in the proton energy spectra detected by satellites since the penetration distance of a proton is not a monotonically increasing or decreasing function of energy. During a storm when the convection E is enhanced, model calculations predict elongations of the forbidden regions analogous to tail extensions of the plasmasphere. Following a reduction in the convection field, spiral-structured forbidden regions can occur. Structural features inherent to large-scale convection field changes may be seen in the nose-like proton spectrograms observed near dusk by instrumentation on Explorer 45. These nose events are modelled by using an electric field model developed originally by Volland (1973). The strength of the field is related to the Kp index through night-time equatorial plasmapause measurements.

Grebowsky, J. M.↗