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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1967

Mercury capillary interrupter Patent

Interrupter switching device utilizing electrodes and mercury filled capillary tubes in which current flow vaporizes mercury as circuit breaker

Heckler, C. H.↗
NASA NTRS1972

Effects of diffusion impairment on O2 and CO2 time courses in pulmonary capillaries.

Simultaneous time courses for O2 and CO2 exchange along the capillary have been calculated for homogeneous lungs, allowing for O2-CO2 interactions, dissolved O2, and chemical reaction rates. As diffusing capacity (Dl) was reduced, the transfer of CO2 and O2 was impaired by similar amounts, in spite of the 20-fold greater diffusing capacity for CO2. The reason why CO2 is affected so much is that the slope of the content against partial pressure is so much greater in blood than tissue for this gas. Because of the shapes of their respective dissociation curves, O2 transfer was most affected at normal ventilation-perfusion ratios, whereas CO2 was most affected at high ratios. Exercise exaggerated the impairment of transfer of both gases.

Wagner, P. D.↗
NASA NTRS1972

High pressure pulsed capillary viscometry

An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

Smith, R. L.↗
NASA NTRS1972

An analytical and experimental investigation of rotating, non-capillary heat pipes

An approximate theoretical model is derived for laminar film condensation on the inside of a rotating, truncated cone, and is used to predict the heat transfer performance of rotating, non-capillary heat pipes for a wide variety of parametric conditions. Experimental results are presented for water, ethyl alcohol, and freon-113 in a stainless steel heat pipe rotating to speeds of 2800 rpm. Results show that these devices can be used effectively to transfer large quantities of heat in rotating systems. Predicted results agree to within + or - 20 percent of the experimental data. Dropwise condensation, instead of film condensation, improves heat pipe performance while the presence of non-condensible gases impairs performance.

Marto, P. J.↗
NASA NTRS1975

Nondestructive measurement of capillary tube internal diameter

Technique provides nondestructive method of making quick, accurate determination by measuring electrical resistance of capillary tube when it is filled with electrolyte of known conductivity. Apparatus consists of conductivity cell and equipment for measuring resistance and for monitoring and controlling temperature.

Ho, W. W.↗
NASA NTRS1975

Buoyant and capillary natural convection in infinite horizontal liquid layers heated laterally

Solutions are presented for the equations describing natural convection in a planar, horizontal layer of liquid with a constant, linear temperature gradient along the unbounded top and bottom surfaces. Both buoyancy and capillary forces are considered to drive thermal convection. The results are compared to earlier analyses for bounded liquid layers and then applied to containerless metal melts undergoing solidification in the microgravity environment of near-earth orbit.

Bourgeois, S. V.↗
NASA NTRS1976

Silicon ribbon growth by a capillary action shaping technique

The technique of silicon ribbon growth by the capillary action shaping is assessed for applicability to photovoltaic power device material. Ribbons 25 mm in width and up to 0.5 m in length have been grown from SiC dies, and some new characteristics of growth from such dies have been identified. Thermal modifiers have been studied, and systems were developed which reduce the frozen-in stress un silicon ribbons and improve the thickness uniformity of the ribbons. Preliminary spreading resistance measurements indicate that neither surface striations nor twin boundaries give rise to appreciable resistivity variations, but that large-angle grain boundaries cause local resistivity increases of up to 200%.

Schwuttke, G. H.↗
NASA NTRS1976

On the variation and growth of wave-slope spectra in the capillary-gravity range with increasing wind

A new laser device has been used to make direct wave-slope measurements in the capillary-gravity range. Owing to the design principles, the digital nature of the system and the use of a laser beam as a probe, the earlier problems of intensity variations and meniscus effects were avoided. Using this new technique, wave-slope spectra both down and across the channel were obtained for different wind conditions, along with corresponding mean-square slope values. Comparisons are made with existing data. The results indicate that a quasi-equilibrium state may exist for each wind speed and that it increases in intensity with increasing wind, which may imply an asymptotic nature for the equilibrium-range coefficient. From the data, two significant frictional velocities, 17.5 and 31 cm/s respectively, are identified as critical values for different ranges of wave development.

Long, S. R.↗