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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 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Structure and function of an inorganic-organic separator for electrochemical cells: Preliminary study

The structure of a new separator material for electrochemical cells has been investigated. Investigation into details of the separator structure showed it to be multilayered and to consist mainly of a quasi-impervious organic skin, a porous region of mixed organic and inorganic material, and an area of nonuniformly treated substrate. The essential feature of the coating (slurry) is believed to be interconnected pores which allow ionic conductivity. The interconnected pores are believed to be formed by the interaction of the plasticizer and inorganic fibers. The major failure mode of silver zinc cells using such a separator (zinc nodules shorting adjacent plates) was investigated.

Bozek, J. M.↗
NASA NTRS1972

Biomedical engineering tasks

Electrocardiographic and vectorcardiographic bioinstrumentation work centered on the development of a new electrode system harness for Project Skylab. Evaluation of several silver electrode configurations proved superior impedance voltage performance for silver/silver chloride electrodes mounted flush by using a paste adhesive. A portable ECG processor has been designed and a breadboard unit has been built to sample ECG input data at a rate of 500 samples per second for arrhythmia detection. A small real time display driver program has been developed for statistical analysis on selected QPS features. Engineering work on a sleep monitoring cap assembly continued.

Source record↗
NASA NTRS1974

Calibration of a cylindrical RF capacitance probe

The calibration is considered of an RF antenna capacitance probe carried aboard the RAE-1 spacecraft and the correction of the probe for external effects, believed to be primarily due to local positive ion sheaths and/or photoelectron sheaths surrounding the antenna. The RAE-1 spacecraft was launched in July 1968 into a 5850-km. Circular orbit of 121-degree inclination and carried several antenna and radiometer systems covering a frequency range of 0.2 to 9.2 MHz for radio astronomical studies. The RF capacitance probe measurements discussed utilized a 37-meter electric dipole antenna formed by two monopoles made of silver-coated beryllium-copper alloy tapes formed into hollow cylindrical tubes 1.3 cm in diameter.

Mosier, S. R.↗
NASA NTRS1974

The transit of Mercury of 10 November 1973

The transit of Mercury of November 10, 1973 was observed from Silver Spring, Maryland (76 deg 58' W, 39 deg 01' N) for the period 6:48:00 EST, near sunrise, to 8:17:18 (contact 4). A total of 24 frames of 35mm Pan X film were taken through a Questar telescope equipped with a sun filter of 40mm aperture. The diameter of the solar image is 13mm on the film. Transit photographs from the observation are included.

Feibelman, W. A.↗
NASA NTRS1974

Skylab Experiment M552: Exothermic Brazing

The M552 Skylab experiment reveals that brazing in space is feasible. It successfully demonstrated the ability to retain molten metal within a braze tube joint system. Surface energy was the dominant operative force system controlling liquid metal for this experiment. The zero gravity environment for brazing resulted in several differences; increased solubility, increased liquid spreading, more uniform menisci (liquid/vapor interface) and a reduction of braze alloy shrinkage defects. The residual radioactive intensity and location of the redistributed isotope was interpreted to provide a sequential history of braze alloy movement during the melt-flow-solidification stages of the process. Convection theory applied to M552 was validated but some results were not explainable by it, i.e., increased nickel transport and the radial mixing of the silver isotope on samples SLN-2 and SLN-4. All characteristics of thermal analysis appeared to react as expected but heat conduction rates increased because of increased extent, rate and uniformity of braze alloy spreading.

J R Williams↗
NASA NTRS1974

Surface topographical effects on the structural growth of thick sputtered metal and alloy coatings

Thick sputtered S-Monel, silver, and 304 stainless steel coatings were deposited on mica and metal substrates with various surface finishes to investigate the structural growth of the coating by scanning electron microscopy. The geometry and the surface structure of the nodules are characterized. Compositional changes within the coating were analyzed by X-ray dispersion miscroscopy. Defects in the surface finish act as preferential nucleation sites and form isolated and complex nodules and various surface overgrowths in the coating. The nodule boundaries are very vulnerable to chemical etching, and these nodules do not disappear after full annealing. Further, they have undesirable effects on mechanical properties; cracks are initiated at the nodules when the coating is stressed by mechanical forces.

Spalvins, T.↗
NASA NTRS1973

Detection of weldment lack of fusion using opaque additives

Problems in the production of aluminum weldments are caused by moisture absorbed by the aluminum oxide which forms on the surface before welding. Another problem is incomplete penetration of the weldment. The problems can be solved by coating the aluminum surfaces with an X-ray-opaque metal such as silver or copper. This will prevent the formation of moisture-absorbing aluminum oxide. Any protective coating remaining in an area of incomplete weld penetration can be seen in an inspection of the weldment conducted with the aid of an X-ray method. Details of copper deposition procedures are discussed along with a copper coating analysis and the testing of the weldments.

Cook, J. L.↗
NASA NTRS1974

Thermal design of the IMP-I and H spacecraft

A description of the thermal subsystem of the IMP-I and H spacecraft is presented. These two spacecraft were of a larger and more advanced type in the Explorer series and were successfully launched in March 1971 and September 1972. The thermal requirements, analysis, and design of each spacecraft are described including several specific designs for individual experiments. Techniques for obtaining varying degrees of thermal isolation and contact are presented. The thermal control coatings including the spaceflight performance of silver-coated FEP Teflon are discussed. Predicted performance is compared to measured flight data. The good agreement between them verifies the validity of the thermal model and the selection of coatings.

Hoffman, R. H.↗
NASA NTRS1975

Dual-band ridged waveguide

Waveguide-in-waveguide technique involves routing two waveguides through same passageway. Smaller waveguide can be soft or silver soldered inside X-band waveguide to form single ridge guide and to propagate frequencies at C-band.

Franke, J. M.↗
NASA NTRS1975

Single crystals of metal solid solutions: A study

Report describes growth of silver-alloy crystals under widely varying conditions of growth rate, temperature gradient, and magnetic field. Role of gravitation and convection on crystal substructure is analyzed, as well as influence of magnetic fields applied during crystallization.

Miller, J. F.↗
NASA NTRS1974

Single crystals of metal solid solutions

The following definitions were sought in the research on single crystals of metal solid solutions: (1) the influence of convection and/or gravity present during crystallization on the substructure of a metal solid solution; (2) the influence of a magnetic field applied during crystallization on the substructure of a metal solid solution; and (3) requirements for a space flight experiment to verify the results. Growth conditions for the selected silver-zinc alloy system are described, along with pertinent technical and experimental details of the project.

Miller, J. F.↗
NASA NTRS1974

Synthesis and evaluation of C-ether formulations for use as high temperature lubricants and hydraulic fluids

The formulation and evaluation of C-ether fluids for use in the hydraulic and lubrication systems of the space shuttle and advanced air breathing engines were studied to lower the pour point of a reference C-ether from -29 C to -40 C without changing its evaporation loss. Use of disiloxanes mixed with C-ethers gave a -40 C pour point fluid with little change in the desired evaporation loss or in oxidative stability. A second -40 C pour point fluid containing only C-ethers was also developed. A screening program tested lubrication additives for C-ethers and the new fluids. Six additive packages were chosen for evaluation in 316 C bearing tests, two for evaluation in 260 C pump tests. The goal of the bearing test was a 100 hour run. The rig was a specially designed 80-mm axially loaded ball bearing. The C-ether base fluid ran only one hour at 316 C before cage wear failure occurred. The best additive blends ran 47, 94 and 100 hours. The 96 hour test gave excessive deposits. The 100 hour test had no wear failures; an unexplained loss of cage silver occurred from areas of direct fluid impingement on the cage.

Clark, F. S.↗
NASA NTRS1972

Wash efficiency tests

Processed film products were tested for residual thiosulfate by precipitation as colored silver sulfide. The quantity of thiosulfate was determined and correlated with the expected storage life of the film.

Maas, K. A.↗
NASA NTRS1974

Identification and interpretation of tectonic features from Skylab imagery

The author has identified the following significant results. A remarkable system of northwest and west-northwest trending faults was found to continue from eastern California into southwestern Arizona. The most significant is a fault belt which extends from west of Marble Mountains (southeastern California) across the Colorado River at Parker Valley towards Silver Bell Mountains, southern Arizona.

Abdel-Gawad, M.↗
NASA NTRS1975

A simple method for estimation of coagulation efficiency in mixed aerosols

Aerosols of KBr and AgNO3 were mixed, exposed to light in a glass tube and collected in the dark. About 15% of the collected material was reduced to silver upon development. Thus, two aerosols of particles that react to form a photo-reducible compound can be used to measure coagulation efficiency.

Dimmick, R. L.↗
NASA NTRS1975

Evaluation of wet tantalum capacitors after exposure to extended periods of ripple current, volume 2

The application of tantalum capacitors in the Viking Lander includes dc voltage and ripple current electrical stress, high temperature during nonoperating times (sterilization), and high vibration and shock loads. The capacitors must survive these severe environments without any degradation if reliable performance is to be achieved. A test program was established to evaluate both wet-slug tantalum and wet-foil capacitors under conditions accurately duplicating actual Viking applications. Test results of the electrical performance characteristics during extended periods of ripple current, the characteristics of the internal silver migration as a function of extended periods of ripple current, and the existence of any memory characteristics are presented.

Ward, C. M.↗
NASA NTRS1975

Factors influence flexibility resistivity and zinc dendrite penetration rate of inorganic separators for alkaline batteries

Developmental work resulted in a formulation which can improve the flexibility of the inorganic-organic-type separator for silver-zinc and nickel-zinc alkaline batteries. The effects of various fillers and reactive organic additives on separator volume resistivity are described. The effects of various inert fillers on the zinc dendrite penetration rate of the separator are shown. Conclusions regarding the operating mechanism of the separator are presented.

Sheibley, D. W.↗