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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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Smith correlation of turbine stage efficiency for relating achievable efficiency to stage loading and flow factors used for total pressure loss coefficient data
Heat transfer coefficient, friction factor, and pressure drop analyzed in flow of gas - solid dilute suspension
Relation between angle of attack envelopes and correlation parameter for spinning bodies entering atmosphere at large inclinations
Liquid and gas viscosity correlation at 1 atm with reduced density for parahydrogen
Quantile system of data compression for space telemetry, discussing operation, efficiency and advantages
Algorithm for generating normally distributed variables set with given correlation matrix in digital computer simulation of electronic circuit performance
Rohsenow nucleate pool-boiling data correlation, stressing coefficients dependence on surface preparation and liquid-surface combination
Use of Doppler tracking data from the Lunar Orbiter series of spacecraft in an analysis of the spherical harmonic coefficients of the lunar gravitational field through thirteenth degree and order. The value obtained for the mass of the moon, GM = 4902.84 cu km/sec/sec, is in good agreement with previous results and with results obtained by alternate procedures. Acceleration contour plots, derived from the gravitational coefficients, show correlations with surface features on the near side of the moon, but are of questionable validity for the far side because of the lack of direct tracking data on the far side. Based on the most recent gravitational field data, the current estimate for the polar moment of inertia of the moon is C/Ma squared = 0.4019 super + 0.004 sub - 0.002. This value indicates that the interior of the moon can be homogeneous, but some results presented strongly suggest that the moon is differentiated, with an excess of mass in the direction toward the earth.
Metals are described by physical appearance followed by atomic weight, atomic number, and valence. Data includes laboratory handling and safety procedures, heat transfer correlations, diffusion coefficients in liquid gallium/indium solution, melting and boiling points, thermal conductivity, heat capacity, and electrical resistivity.
Measurement by systolic time intervals (STI) of cardiac responses requires extremely careful recording during actual stress test performance. Previous work indicated no significant changes in the pulse transmission time (PTT) during exercise and other challenges. Since external STI depend on the carotid pulse offset by the PTT as an aortic curve equivalent, stable PTT implies that timing of the carotid upstroke and the carotid incisura would respectively track the pre-ejection period and the aortic incisura. In ten subjects, STIs were recorded at supine rest, sitting, standing, during prompt and sustained squatting and during isometric and dynamic exercise. The results demonstrated the tracking of both points. Coefficients of correlation and of determination were uniformly high for all challenges except isometric handgrip (IHG). Since left ventricular ejection time is obtained directly from the pulse curve, with the exception of IHG, STI responses during stress testing can be measured without a phonocardiogram.
A land use map of a five county area in North Alabama was generated from LANDSAT data using a supervised classification algorithm. There was good overall agreement between the land use designated and known conditions, but there were also obvious discrepancies. In ground checking the map, two types of errors were encountered - shift and misclassification - and a method was developed to eliminate or greatly reduce the errors. Randomly selected study areas containing 2,525 pixels were analyzed. Overall, 76.3 percent of the pixels were correctly classified. A contingency coefficient of correlation was calculated to be 0.7 which is significant at the alpha = 0.01 level. The land use maps generated by computers from LANDSAT data are useful for overall land use by regional agencies. However, care must be used when making detailed analysis of small areas. The procedure used for conducting the ground truth study together with data from representative study areas is presented.
New evidence is presented that for aqueous glycerol solutions, the Soret coefficient of glycerol, sigma sub 1 = D sub 1 T/D sub 1 (where D sub 1 T and D sub 1 are the thermal and self-diffusion coefficients, respectively, of glycerol in aqueous solutions), is an integral part of the heat of mixing parameter. Expressions are presented indicating the importance of the Soret coefficients to correlations for diffusion processes in glycerol water solvents.
The energy transfer catalytic recombination coefficient for nitrogen and oxygen recombination on the surface coating of high-temperature reusable surface insulation (HRSI) is inferred from stagnation point heat flux measurements in a high-temperature dissociated arc jet flow. The resulting catalytic recombination coefficients are correlated with an Arrhenius model for convenience, and these expressions may be used to account for catalytic recombination effects in predictions of the heat flux on the HRSI thermal protection system of the Space Shuttle Orbiter during reentry flight. Analysis of stagnation point pressure and total heat balance enthalpy measurements indicates that the arc heater reservoir conditions are not in chemical equilibrium. This is contrary to what is usually assumed for arc jet analysis and indicates the need for suitable diagnostics and analyses, especially when dealing with chemical reaction phenomena such as catalytic recombination heat transfer effects.
The energy-transfer catalytic recombination coefficient for nitrogen and oxygen recombination on iron-cobalt-chromia spinel is inferred from stagnation-point heat flux measurements in dissociated arc-jet flow. This material was coated on several Space Shuttle Orbiter thermal protection tiles. The resulting coefficients are correlated with an Arrhenius model for convenience, and these expressions may be used to account for catalytic recombination in predictions of the heat flux on the spinel-coated tiles flown on several Space Shuttle Orbiter flights. The results are compared with those inferred by Rakich, Stewart, and Lanfranco from an Orbiter flight and arc-jet experiments. Good agreement is obtained for oxygen recombination, but agreement for nitrogen is poor.
The dynamic characteristics of the Solar Array Flight Experiment (SAFE) structure during deployment and retraction are investigated. The SAFE structure consists of a deployable mast with an attached solar blanket designed with accordion type folds to permit packaging in a small volume. The planar form of the blanket geometry during deployment is maintained by a blanket tension/guidewire system. Structurally, the mast is modeled as an Euler beam column with inplane and out of plane bending and finite torsional stiffness. For out of plane motion, the blanket is modeled as a distributed mass uniformly supported by the three guidewires. For inplane motion the blanket displacements are assumed to vary linearly from the mast base to the mast tip. The mathematical model uses a virtual work formulation, required because the axial loading on the mast is nonconservative, combined with assumed beam modes to derive the differential equations of motion. Consideration of the time dependent boundary conditions results in an infinite set of ODE with time dependent coefficients. Finally, correlation of mast tip accelerations to mast base bending moments for specified modal motions are indicated.
The thickness distribution of plains-forming materials in Hesperia Planum is determined by the diameter of partially buried craters. As with all Martian thickness studies, the distribution of measured thicknesses is sparse due to a low number of suitable partially buried craters. The resulting isopach of plains materials has a low level of confidence but is sufficient for generalized thickness trends. The mean of the thickness estimates is 360 + or - 120 m. The isopach of plains-forming materials exhibits an uneven thickness distribution. Average thickness, determined by grid sampling over the region, is 216 + or - 153 m. Local lenses exceed 500 m. A fifth order trend surface provides a partial match (coefficient of correlation = 0.657) to the isopach.
A numerical analysis has been conducted with the three-dimensional panel code VSAERO for two interacting lifting surfaces that are separated in the spanwise direction by a narrow gap, with the angle of attack of the outboard section being set independently of the inboard section, as in the 'free tip' rotor blade system proposed for helicopters. Computed values of tip surface lift and pitching moment coefficients are correlated with experimental data to determine the most suitable method for modeling the gap region between the surfaces. It is shown that the induced drag of the tip surface is reduced for negative incidence angles relative to the inboard section.
Based on 'annual' averages, a bivariate analysis of the maximum amplitude of the sunspot cycle against its minimum amplitude and the minimum value of the aa geomagnetic index (in the vicinity of sunspot cycle minimum) results in a fit that closely matches the observable record. The bilinear fit has a high coefficient of correlation (r = 0.982) and a small standard deviation (s = 9.5), suggesting that it may be useful for predicting the size of a sunspot cycle 3 to 4 years before maximum amplitude occurrence. Applying the fit to cycle 22, the annual average of maximum amplitude is found to be 92 + or - 19 (equivalent to 96 + or - 20 in terms of the 13-month running mean or smoothed sunspot number).