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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 451 records · Page 25

Preliminary Analysis of STS-3 Entry Heat-Transfer Data for the Orbiter Windward Centerline

A preliminary analysis of heat transfer data on the space shuttle orbiter windward centerline for the STS-3 mission entry is presented. Temperature-time history plots for each measurement location and tabulated wall temperature and convective heating rate data at 21 selected trajectory points are included. The STS-3 flight data are also compared with predictions by two approximation methods for computing convective heat transfer rates in equilibrium air.

Throckmorton, D. A.↗

Study of activation of metal samples from LDEF-1 and Spacelab-2

The activation of metal samples and other material orbited onboard the Long Duration Exposure Facility (LDEF) and Spacelab-2 were studied. Measurements of the radioactivities of spacecraft materials were made, and corrections for self-absorption and efficiency were calculated. Activation cross sections for specific metal samples were updated while cross sections for other materials were tabulated from the scientific literature. Activation cross sections for 200 MeV neutrons were experimentally determined. Linear absorption coefficients, half lives, branching ratios and other pertinent technical data needed for LDEF sample analyses were tabulated. The status of the sample counting at low background facilities at national laboratories is reported.

Laird, C. E.↗

Space shuttle: Aerodynamic characteristics of a composite booster/040A orbiter launch configuration with fin and booster body configuration effect contribution

An investigation was made of the fin configuration and booster body configuration effects on a composite booster/040A orbiter launch configuration. Aerodynamic performance and stability characteristics in pitch and yaw were obtained. Configurations tested included two stepped cylindrical bodies of different lengths with a conical nose, four fin shapes of various sizes and aspect ratios mounted in different positions around the base of the bodies, two base flare angles and three 040A orbiter configurations. The orbiter variations included a tailless configuration and two tail sizes. A tailless booster launch configuration with deflected petals (expanded flare sectors) was also tested. The model scale was 0.003366. Data were converted to coefficient form in near real time, punched on cards, and tabulated. The cards used in conjunction with a Benson-Lehner plotter were used to provide plotted data. At the end of the test, tabulated input forms were completed for the SADSAC computer program to aid in publishing the final test data report.

Ainsworth, R. W.↗

Correlation Calculations for the Russian Pu Metal Fast Experiments

Nuclear criticality experiments are often conducted in campaigns with multiple variations. These experiments reuse the same basic components, like the fuel, moderator, or positioning machines. The components have uncertainties in their geometry and composition that propagate to models of the experiments. Shared components create shared uncertainty between the $k_{eff}$ of benchmarks. The shared uncertainty is commonly quantified with a covariance, or correlation coefficient. These covariances can impact criticality safety and nuclear data validation applications. While benchmark evaluations tabulate an experiment’s uncertainty, they often lack a detailed calculation of correlations between experiments. Even some very commonly used benchmarks, like the Russian Pu Metal Fast (PMF) experiments, have missing correlations. This paper presents our approach to calculate the correlations for five of the Russian PMF experiments. The experiments share hemispherical Pu shells that induce a correlation between modeled $k_{eff}$ values. We estimated the correlations with simplified and detailed models of the experiments through linear-perturbation theory. The correlations between the experiments vary significantly between the detailed vs. simplified models. We also investigate how the correlations affect validation metrics of the experiments.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Westcott g factors extended to arbitrary neutron energy spectra

Westcott 𝑔 factors are used in Neutron Activation Analysis (NAA) and Prompt Gamma-ray Activation Analysis (PGAA) to evaluate the impact of non-1∕𝑣 behavior in the neutron-capture cross sections of certain nuclei on activation product yields. This non-1∕𝑣 behavior arises from the presence of neutron resonances in the neutron- capture cross sections that overlap with the source neutron spectrum at low (< 5 eV) energies. Historically, Westcott 𝑔 factors that have been cataloged for NAA and PGAA applications are the result of calculations that assume a Maxwellian neutron flux distribution with a given temperature. In this work, we use this approach with updated neutron-capture cross sections from the Evaluated Nuclear Data File, version VIII.1 (ENDF/B-VIII.1) to tabulate Westcott 𝑔 factor values for a broad range of Maxwellian distribution temperatures, comparing the results against currently-available 𝑔 factors from International Atomic Energy Agency tables and other sources. Here, it was discovered during this analysis that the use of guided thermal and cold-neutron beams at certain facilities necessitates an approach for evaluating Westcott 𝑔 factors based on arbitrary non-Maxwellian spectra. In this paper, we present an approach for calculating 𝑔 factors with user-specified neutron spectra, and we demonstrate these methods to obtain Westcott 𝑔-factors for guided- and cold-neutron beams at the Budapest Research Reactor and the Forschungsreaktor München II reactor. As part of this work, open-source software has been developed that can be used to perform these calculations for applications in PGAA and NAA experiments.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Nuclear β − -decay with statistical de-excitation

he accurate description of nuclear β − -decay has far-reaching consequences for applications spanning nuclear reactors to the creation of heavy elements in astrophysical environments. We present the nuclear particle spectra associated with the β -decay of neutron-rich nuclei calculated with the well benchmarked coupled Quasi-particle Random Phase Approximation and Hauser–Feshbach (QRPA+HF) model. This approach begins with the population of the daughter nucleus via semi-microscopic Gamow-Teller or First-Forbidden strength distributions (QRPA) and follows the statistical de-excitation (HF) until the initial available excitation energy is exhausted. At each stage of de-excitation the emission by neutrons and $γ$-rays is considered obeying quantum mechanical selection rules. For completeness we also provide parsed Auger and Internal Conversion (IC) electron spectra from Evaluated Nuclear Data Files (ENDF). Our results are tabulated and provided in parsable ASCII formatted tables that are suitable for inclusion in various applications.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Verification Problems for Smooth Step Amplitude Load Curves in DYNA3D/Paradyn

This report documents the addition of three new verification tests in the LOADCURVE directory of the DYNA3D/Paradyn Software Quality Assurance test suite. Each test consists of a single element, where the velocities of each node are specified by either the newly added smooth step tabular load curve or another load curve option. The first test assesses the initialization and interpolation of the newly inputted load curve option through tabulated abscissa-ordinate pairs of data. The second test uses the same set of abscissa-ordinate data points and applies offset and scaling parameters available within the load curve definition. The third test defines the smooth step load curve in an original input deck, and assesses its correct redefinition using a restart file. The simulation velocities are compared to their true values at discrete points in time, and each test is verified up to numerical precision. These results confirm that the smooth step load curve option is functioning correctly and as intended.

97 MATHEMATICS AND COMPUTING↗

Pressure Distribution Induced on a Flat Plate at a Free-Stream Mach Number of 1.39 by Rockets Exhausting Upstream and Downstream

An experimental investigation was made of the pressures induced on a flat plate at a free-stream Mach number of 1.39 by a supersonic rocket jet exhausting upstream and downstream. Measurements of the pressure distribution on a flat plate were made at zero angle of attack for 11 different locations of the jet exhaust nozzle beneath the wing. Measurements were made at ratios of rocket-exit total pressure to freestream static pressure from 6 to 60 and at a Reynolds number per foot of approximately 10 x 10 6 . The rocket when exhausted upstream produced a strong shock that moved further upstream with increasing rocket-exit total-pressure ratio. Positive incremental normal-force coefficients were obtained at all test positions. Data at 11 test positions are tabulated for rocket-on and rocket-off pressure coefficients as well as for incremental pressure coefficients for the 48 orifices of the flat plate for the range of ratio of rocket-exit total pressure to free-stream static pressure of the investigation. Changing the location of the model with respect to the plate had a negligible effect when the rocket was varied in the chordwise direction, but the pressure coefficients were reduced as the rocket was lowered away from the flat-plate wing.

Supersonic jet↗

Assuring reliability program effectiveness.

An attempt is made to provide simple identification and description of techniques that have proved to be most useful either in developing a new product or in improving reliability of an established product. The first reliability task is obtaining and organizing parts failure rate data. Other tasks are parts screening, tabulation of general failure rates, preventive maintenance, prediction of new product reliability, and statistical demonstration of achieved reliability. Five principal tasks for improving reliability involve the physics of failure research, derating of internal stresses, control of external stresses, functional redundancy, and failure effects control. A final task is the training and motivation of reliability specialist engineers.

Ball, L. W.↗

Relative stiffness of flat-conductor cable

Bending moment data were taken on ten different cable samples and normalized to express all stiffness factors in terms of cable 5.1 cm in width. Relative stiffness data and nominal physical characteristics are tabulated and presented in graphical form for designers who may be interested in finding torques exerted on critical components by short lengths of cable.

Hankins, J. D.↗

An investigation to determine the static pressure distribution of the 0.00548 scale shuttle solid rocket booster (MSFC model number 468) during reentry in the NASA/MSFC 14 inch trisonic wind tunnel (SA28F)

The results of a pressure test of a .00548 scale 146 inch Space Shuttle Solid Rocket Booster (SRB) with and without protuberances, conducted in a 14 x 14 inch trisonic wind tunnel are presented. Static pressure distributions for the SRB at reentry attitudes and flight conditions were obtained. Local longitudinal and ring pressure distributions are presented in tabulated form. Integration of the pressure data was performed. The test was conducted at Mach numbers of 0.40 to 4.45 over an angle of attack range from 60 to 185 degrees. Roll angles of 0, 45, 90 and 315 degrees were investigated. Reynolds numbers per foot varied for selected Mach numbers.

Braddock, W. F.↗

Satellite to satellite tracking error analysis studies and data processing

An error analysis was conducted to examine the effects of placing the target satellite in an orbit nearly coplanar with the relay satellite and of data span length on the accuracy with which the satellite states can be recovered. An analysis of error models using actual satellite to satellite tracking data spans is included. Results are tabulated.

Ayres, C. L.↗

Data Quality: 1979 Southeastern Virginia Urban Plume Study (SEV-UPS): Surface and Airborne studies

The SEV-UPS field study conducted during August 1979 involved the coordinated air quality data collection efforts of three different organizations operating a total of four aircraft and 12 ground stations. Incorporated into plans for that program were numerous quality assurance activities designed to identify potential hazards for data quality in time for their correction and to take data to allow assessment of the consistency of the data from different stations. The purpose of this study was to document QA procedures that were performed by participating agencies and revise data from all platforms for mutual compatibility. For the latter effort, cases were identified on 21 occasions on seven different days where two or more monitoring systems were operating in the same location at nearly the same time. Data from the systems involved were tabulated in 200 m altitude segments, averaged and compared to detect any bias between measurements made from different systems. The results of these comparisons along with the results of independent performance audits are presented.

White, J. H.↗

The use of large-scale aerial photography for interpreting Landsat digital data in an elk habitat-analysis project

Large-scale aerial photography was used to interpret Landsat multispectral scanner data processed through an unsupervised classifier. After scale adjustment and interpretation by application of an elk-habitat photointerpretation legend, the photographs were registered with the spectral classification, and the co-occurrence of spectral picture elements with photointerpreted habitat classes was tabulated. Analysis of the resulting table of data permitted the description of spectral classes in terms meaningful and useful to elk research and management unit in the Blue Mountains of northeastern Oregon.

Isaacson, D. L.↗

Spectral reflectances of natural targets for use in remote sensing studies

A collection of spectral reflectances of 156 natural targets is presented in a uniform format. For each target both a graphical plot and a digital tabulation of reflectance is given. The data were taken from the literature and include laboratory, field, and aircraft measurements. A discussion of the different measurements of reflectance is given, along with the changes in apparent reflectance when targets are viewed through the atmosphere. The salient features of the reflectance curves of common target types are presented and discussed.

Bowker, D. E.↗