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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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130 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1942

Supplementary Spin Tests of a 1/20-Scale Model of the Bell XP-39E Airplane

As a result of the loss of the first XP-39E airplane due to an uncontrolled spin, and at the request of the War Department received in their letter to the NACA, March 31, 1942, additional tests have been made of the corresponding 1/20-scale spin-tunnel model. Tests were made for the normal full load condition and also for the loading condition corresponding to that of the airplane at the time of the crash, that Is, with guns, ammunition, and half of the fuel removed from the wings. The model tests were made with the tail arrangement corresponding to that of the airplane at the time of the crash, as well as with numerous modified tail and contour arrangements In an attempt to evolve satisfactory recovery characteristics. The tests were started on April 2, 1942, and completed in approximately two weeks, with the development of several alternate tail arrangements giving reasonably satisfactory recoveries for normal spinning control configuration. The tests were witnessed by Mr. Melvin Shorr, of the Materiel Center at Wright Field, and Mr. Paul C. Emmons, of the Bell Aircraft Corporation, to whom records of the test data were furnished. Colonel H. P. Swofford, of the Materiel Center, Wright Field, also witnessed part of the tests. A preliminary report of the results of the tests has been forwarded to the Materiel Command at Wright Field. A brief check of the parachute installation for the airplane was also made.

A I Neihouse↗
NASA NTRS2023

Territory and Population Attributes Affect Florida Scrub-Jay Fecundity in Fire Adapted Ecosystems

Fecundity, the number of young produced by a breeding pair during a breeding season, is a primary component in evolutionary and ecological theory and applications. Fecundity can be influenced by many environmental factors and requires long-term study due to the range of variation in ecosystem dynamics. Fecundity data often include a large proportion of zeros when many pairs fail to produce any young during a breeding season due to nest failure or when all young die independently after fledging. We conducted color banding and monthly censuses of Florida scrub-jays (Aphelocoma coerulescens) across 31 years, 15 populations, and 761 territories along central Florida’s Atlantic coast. We quantified how fecundity (juveniles/pair-year) was influenced by habitat quality, presence/absence of nonbreeders, population density, breeder experience, and rainfall, with a zero-inflated Bayesian hierarchical model including both a Bernoulli (e.g., brood success) and a Poisson (counts of young) submodel, and random effects for year, population, and territory. The results identified the importance of increasing “strong” quality habitat, which was a mid-successional state related to fire frequency and extent, because strong territories, and the proportion of strong territories in the overall population, influenced fecundity of breeding pairs. Populations subject to supplementary feeding also had greater fecundity. Territory size, population density, breeder experience, and rainfall surprisingly had no or small effects. Different mechanisms appeared to cause annual variation in fecundity, as estimates of random effects were not correlated between the success and count submodels. The increased fecundity for pairs with nonbreeders, compared to pairs without, identified empirical research needed to understand how the proportion of low-quality habitats influences population recovery and sustainability, because dispersal into low-quality habitats can drain nonbreeders from strong territories and decrease overall fecundity. We also describe how long term study resulted in reversals in our understanding because of complications involving habitat quality, sociobiology, and population density.

Long-term studies↗
NASA NTRS2019

Isotopologue Consistency of Semi-Empirically Computed InfraRed Line Lists and Further Improvement for Rare Isotopologues: CO2 and SO2 Case Studies.

The semi-empirical molecular rovibrational IR line lists, such as ExoMol, TheoReTs, and Ames, combine the experimental accuracy and theoretical power to reach better than 0.1 cm-1 accuracy for line positions and better than 80-90% agreement for line intensities. The quality of these existing semi-empirical IR lists allows further improvements of intensity and line positions for those unobserved minor isotopologues. This paper presents our new BTRHE (Best Theory + Reliable High-resolution Experiment) strategy implementation. For line intensity, the isotopologue consistency and the patterns of mass dependence in the Ames-296K SO2 and CO2 IR lists are quantitatively presented along the mass-inverse coordinates. The consistency and patterns are better than those in existing experimental data. The methodology proposed here can be used to identify inconsistencies, outliers, and mistakes in intensities, and help improve Effective Dipole Model (EDM) and molecular IR databases. We call for an experimental study on the 50006 and 60007 bands of CO2 628. For line position predictions, a simple approach combining the variational IR line lists with Effective Hamiltonian (EH) model may refine the effective rotational constants A0/B0/C0 and quartic centrifugal distortion constants of minor isotopologues. The prediction accuracy may be improved by two orders of magnitude, i.e. reaching 0-5 MHz prediction accuracy in the range of J<20-30, Ka<10-20, and 0.01-0.02 MHz accuracy for A0/B0/C0. Several important factors have been systematically investigated and discussed, e.g. convergence, uncertainties, higher order terms, fixing EH parameters, mass coordinates, etc. Amicrowave (MW) line set consisting of 644,636 strong transitions for all 30 isotopologues and corresponding refined EH(Ames) parameters are reported in the supplementary material. This approach may be easily extended to rovibrational bands, hot bands, and other molecular systems.

Xinchuan Huang↗
NASA NTRS2011

VEGGIE Pillow Testing: Microbial Analysis of Cut-and-Come-Again Species Testing

With NASA focused on researching and developing technology for deep space missions, the need for a reliable supplementary food source must also be considered. For the ISS, resupplying the food source is more practical and cost effect since the facility is in low Earth orbit. However, as NASA attempts to push the frontier in space, the costs and distance for resupply will surely increase. Plants would contribute to the proportion of food and reduce the dependency on food from Earth. In addition, plants would provide oxygen production, carbon dioxide removal, and psychological benefits. As a result, a vegetable production system, VEGGIE, was developed for NASA to produce salad crops with minimal resources and study the beneficial effects. The VEGGIE pillow is a single use bag for growing crops that is used with the VEGGIE hardware. The VEGGIE pillow was tested with four different species of plants with the cut-and-come-again harvest method to determine the greatest yield. Instead of harvesting the entire plant, the harvest consisted of cutting leaves to allow the plant to regrow leaves. The harvest methods included cutting the plants weekly, bi-weekly, and monthly. A fifth plant species, radishes, was also harvested and replanted. Microbial load analysis and an ANOVA significance test were utilized. The data suggest that the two Brassica plants have the greatest yields; however, the microbial load is also greatest for the two plants per gram of fresh weight. Furthermore, the results support the reuse of pillows for multiple harvests as shown by the replanted radishes.

Nguyen, Bao-Thang↗