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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Small Interactive Image Processing System (SMIPS) users manual

The Small Interactive Image Processing System (SMIP) is designed to facilitate the acquisition, digital processing and recording of image data as well as pattern recognition in an interactive mode. Objectives of the system are ease of communication with the computer by personnel who are not expert programmers, fast response to requests for information on pictures, complete error recovery as well as simplification of future programming efforts for extension of the system. The SMIP system is intended for operation under OS/MVT on an IBM 360/75 or 91 computer equipped with the IBM-2250 Model 1 display unit. This terminal is used as an interface between user and main computer. It has an alphanumeric keyboard, a programmed function keyboard and a light pen which are used for specification of input to the system. Output from the system is displayed on the screen as messages and pictures.

Moik, J. G.↗
NASA NTRS1973

An economical method of analyzing transient motion of gas-lubricated rotor-bearing systems.

A method of economically evaluating the hydrodynamic forces generated in a gas-lubricated tilting-pad bearing is presented. The numerical method consists of solving the case of the infinite width bearing and then converting this solution to the case of the finite bearing by accounting for end leakage. The approximate method is compared to the finite-difference solution of Reynolds equation and yields acceptable accuracy while running about one-hundred times faster. A mathematical model of a gas-lubricated tilting-pad vertical rotor systems is developed. The model is capable of analyzing a two-bearing-rotor system in which the rotor center of mass is not at midspan by accounting for gyroscopic moments. The numerical results from the model are compared to actual test data as well as analytical results of other investigators.

Falkenhagen, G. L.↗
NASA NTRS1973

Equatorial thermospheric composition and its variations.

The neutral atmospheric composition experiment on the San Marco 3 satellite has measured the composition of the equatorial atmosphere from Apr. 29 to Nov. 29, 1971. Preliminary results on the diurnal variation of atmospheric composition from May 19 to June 30 at 225 km altitude are presented. The diurnal variation of helium is seen to reach its maximum near 0800 hours and its minimum in the late afternoon, in contrast to the behavior of molecular nitrogen and argon. The atomic oxygen densities show smaller variations than those of the other gases. The mass densities calculated from the composition data agree well with those determined from the in situ drag force measurements and from orbital decay measurements.

Newton, G. P.↗
NASA NTRS1973

The role of antimatter in big-bang cosmology

Big bang cosmology is discussed with reference to both its strong points and gaps. Characteristics of a spectral component of red shifted gamma-radiation from cosmological matter-antimatter annihilation show a flattening of the gamma-ray spectrum in the vicinity of 1 MeV, an increased gamma-ray flux between 1 and 100 MeV, and a very steep spectrum between 50 and 135 MeV. This data fits well with the theoretical predictions in energy and intensity.

Stecker, F. W.↗
NASA NTRS1973

Heat transfer phase change paint test (OH-42) of a Rockwell International SSV orbiter in the NASA/LRC Mach 8 variable density wind tunnel

Phase change paint tests of a Rockwell International .00593-scale space shuttle orbiter were conducted in the Langley Research Center's Variable Density Wind Tunnel. The test objectives were to determine the effects of various wing/underbody configurations on the aerodynamic heating rates and boundary layer transition during simulated entry conditions. Several models were constructed. Each varied from the other in either wing cuff radius, airfoil thickness, or wing-fuselage underbody blending. Two ventral fins were glued to the fuselage underside of one model to test the interference heating effects. Simulated Mach 8 entry data were obtained for each configuration at angles of attack ranging from 25 to 40 deg, and a Reynolds number variation of one million to eight million. Elevon, bodyflap, and rudder flare deflections were tested. Oil flow visualization and Schlieren photographs were obtained to aid in reducing the phase change paint data as well as to observe the flow patterns peculiar to each configuration.

Jones, R.↗
NASA NTRS1974

Semiconductor measurement technology: Microelectronic ultrasonic bonding

Information for making high quality ultrasonic wire bonds is presented as well as data to provide a basic understanding of the ultrasonic systems used. The work emphasizes problems and methods of solving them. The required measurement equipment is first introduced. This is followed by procedures and techniques used in setting up a bonding machine, and then various machine- or operator-induced reliability problems are discussed. The characterization of the ultrasonic system and its problems are followed by in-process bonding studies and work on the ultrasonic bonding (welding) mechanism. The report concludes with a discussion of various effects of bond geometry and wire metallurgical characteristics. Where appropriate, the latest, most accurate value of a particular measurement has been substituted for an earlier reported one.

Harman, G. G.↗
NASA NTRS1974

Investigation of arterial gas occlusions

The effect of noncondensable gases on high-performance arterial heat pipes was investigated both analytically and experimentally. Models have been generated which characterize the dissolution of gases in condensate, and the diffusional loss of dissolved gases from condensate in arterial flow. These processes, and others, were used to postulate stability criteria for arterial heat pipes under isothermal and non-isothermal condensate flow conditions. A rigorous second-order gas-loaded heat pipe model, incorporating axial conduction and one-dimensional vapor transport, was produced and used for thermal and gas studies. A Freon-22 (CHCIF2) heat pipe was used with helium and xenon to validate modeling. With helium, experimental data compared well with theory. Unusual gas-control effects with xenon were attributed to high solubility.

Saaski, E. W.↗
NASA NTRS1974

Measurement and correlation of aerodynamic heating to surface corrugation stiffened structures in thick turbulent boundary layers

The flow conditions for which heating distributions were measured on corrugated surfaces and wavy walls in turbulent boundary layers are shown, along with the ratio of the displacement thickness to the roughness height versus the local edge Mach number for an equivalent smooth surface. The present data are seen to greatly extend the range of data available on corrugated surfaces in turbulent boundary layers. These data were obtained by testing fullscale corrugation roughened panels in the wall boundary layer of a supersonic and hypersonic wind tunnel. The experimental program used to obtain the data is described. The data are analyzed and correlated in terms of the pertinent flow and geometric parameters. The developed correlations are compared with the available thin boundary layer data, as well as with previously published correlation techniques.

Brandon, H. J.↗
NASA NTRS1973

Average correlation functions in on-line testing of linear systems

This paper is a report on new methods for on-line testing of single-input/single-output linear and time-invariant systems. No interruption of system operation is necessary, since the signals used in this test procedure are the normal operating signals. Test results indicate that detectable system errors using finite amounts of data are well within tolerance for normal operation in all but the most stringent applications.

Mix, D. F.↗
NASA NTRS1973

Atmospheric effects on RF propagation due to turbulence in the Venus atmosphere

Although there have been several theoretical studies and predictions of the Venus atmospheric effects on the radio-frequency wave propagation, the limited experimental data of Venera 4, 5, 6 and 7 do not provide a consistent answer on how severe the turbulence effects could be especially near the Venus surface. In this paper the status of this problem is examined. Important theoretical results are presented. Some meaningful conclusions are drawn from the available experimental data as well as the theoretical analysis.

Chen, C. H.↗
NASA NTRS1975

Experimental evaluation of the tensor polynomial failure criterion for the design of composite structures

The experimental measures and techniques are described which are used to obtain the strength tensor components, including cubic terms. Based on a considerable number of biaxial pressure tests together with specimens subjected to a constant torque and internal pressure, a modified form of the plane stress tensor polynomial failure equation was obtained that was capable of predicting ultimate strength results well. Preliminary data were obtained to determine the effect of varying post cure times and ambient temperatures (-80 F to 250 F) on the change in two tensor strength terms, F sub 2 and F sub 22. Other laminate configurations yield corresponding variations for the remaining strength parameters.

Tennyson, R. C.↗
NASA NTRS1975

Forearm blood flow during body temperature transients produced by leg exercise

Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 C and vapor pressures of less than 18 torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow was measured by electrocapacitance plethysmography. Data are well accounted for by a linear equation independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise.

Wenger, C. B.↗
NASA NTRS1975

Sequential filtering applied to the determination of tracking station locations

The extended sequential filter has been applied to the problem of dynamically determining the geocentric coordinates of two laser satellite tracking stations. This filter provides significant advantages over the classical batch methods through (1) fewer iterations required for convergence, (2) wider radius of convergence, and (3) availability of the parameter estimate evolution. Processing the data sequentially readily identifies the data arcs required to minimize the effects of geopotential model errors. By means of the Smithsonian standard earth 2 and the Goddard earth model 1 geopotentials to reduce laser range observations of the Beacon Explorer-C satellite, it is demonstrated that a two-pass arc is optimal for estimating the height of one station and all coordinates of the second station while minimizing the effect of geopotential model error. These two-pass estimates are in good agreement with other determinations that utilize considerably more data as well as different satellites.

Schutz, B. E.↗
NASA NTRS1975

Computer simulation of transonic flow past airfoils with boundary layer correction

A computer program has been developed to solve the compressible flow equation for the velocity potential. The exterior of the airfoil is mapped onto the unit circle and the flow is computed on a grid in the circle plane. A relaxation method using backward differencing in the flow direction at supersonic points permits solutions for large supersonic areas. The pressure distribution resulting from the flow becomes the input to the von Karman momentum equation which when integrated gives the displacement thickness. This displacement thickness is smoothed and added to the airfoil to account for the turbulent boundary layer. The boundary layer correction is computed iteratively with the flow. Results from this program and test data agree well.

Bauer, F.↗
NASA NTRS1975

A wall-wake velocity profile for turbulent compressible boundary layers with heat transfer

A modified form of the wall-wake profile which is applicable to flows with heat transfer is presented. The modified profile takes into account the effect of a turbulent Prandtl number; it was found to provide a good representation of the experimental data from several sources. The C sub f values which are determined by a least squares fit of the profile to the data agree well with values which were measured by the floating element technique.

Sun, C. C.↗
NASA NTRS1975

Wall-wake velocity profile for compressible non-adiabatic flows

A form of the wall-wake profile, which is applicable to flows with heat transfer, and for which a variation in y = O at y = delta, was suggested. The modified profile, which takes into account the effect of turbulent Prandtl number, was found to provide a good representation of experimental data for a wide range numbers and heat transfer. The Cf values which are determined by a least squares fit of the profile to the data agree well with values which were measured by the floating element technique. In addition, the values of delta determined by the fit correspond more closely to the outer edge of the viscous flow region than those obtained with earlier versions of the wall-wake profile.

Sun, C. C.↗
NASA NTRS1975

Louisiana comprehensive planning information system

A statewide computerized land use mapping system is reported that uses polygons to identify inventories from aerial photography by employing the USGS classification system. In addition, the system provides soil, population, and housing census data as well as economic indicators that can be useful in relating to the overall system.

Ryan, P. W.↗