Results for “ELEMENT 114” | Engineering Papers

NASA NTRS1988

Superconductivity up to 114 K in the Bi-Al-Ca-Sr-Cu-O compound system without rare-earth elements

Stable superconductivity up to 114 K has been reproducibly detected in Bi-Al-Ca-Sr-Cu-O multiphase systems without any rare-earth elements. Pressure has only a slight positive effect on T(c). These observations provide an extra material base for the study of the mechanism of high-temperature superconductivity and also the prospect of reduced material cost for future applications of superconductivity.

Chu, C. W.↗

NASA NTRS1985

A very important process of nucleosynthesis in stars

When some nuclei are free from strong gravitational field, they are unstable and will become stable nuclei by competitions of following processes: (1) neutron-evaporation; (2) spontaneous fission; and (3) beta prime 3-decay. At the initial stage, (1) and (2) are important and (3) can be ignored. The qualitative results are as follows: (1) it seems that nuclei with A 100 come from the spontaneous fission and beta prime decay of neutron-evaporated nuclei with A similiar to 140-440, which can replace the r-process; (2) the super-heavy elements with Z=114--126 (A similiar to 330--360) can be formed. They can be observed in cosmic rage if they have the halftime T 10 to the 7th poweer years; (3) the peak in the rare-earth elements comes from the symmetric fission of super-heavy elements; (4) there are more neutron-rich nuclei in the fragments; and (5) the abundances of a 83 elements in cosmic rays are one order of magnitude higher than that in the solar system.

Yu, C.↗

NASA NTRS1975

Extinct superheavy element in the Allende meteorite

Radiochemical neutron activation analysis of seven Allende samples for 26 trace elements were conducted. In addition, Cr and Fe were studied with the aid of instrumental neutron activation analysis. The investigation had the objective to identify the extinct superheavy element which was present in meteorites and decayed to Xe isotopes by spontaneous fission. The superheavy element was found to reside mainly in a rare mineral (probably a Fe, Ni, Cr, Al-sulfide), comprising only 0.04% of the meteorite. It is pointed out that of the nine volatile superheavy elements 111 to 119, only 115, 114, and 113 are expected to condense as sulfides in the temperature interval between 400 and 500 K corresponding to mineral formation conditions in the solar nebula.

Anders, E.↗

NASA NTRS1992

Panchromatic spectrograph with supporting monochromatic imagers

The Arizona Imager/Spectrograph is a set of imaging spectrographs and 2D imagers for space flight. Nine nearly identical spectrographs record wavelengths from 114 to 1090 nm with a resolution of 0.5-1.3 nm. The spatial resolution along the slit is electronically selectable and can reach 192 elements. Twelve passband imagers cover wavelengths in the 160-900-nm range and have fields of view from 2 to 21 deg. The spectrographs and imagers rely on intensified CCD detectors to achieve substantial capability in an instrument of minimum mass and size. By use of innovative coupling techniques only two CCDs are required to record images from 12 imagers, and single CCDs record spectra from pairs of spectrographs. The fields of view of the spectrographs and imagers are coaligned, and all spectra and images can be exposed simultaneously. A scan platform can rotate the sensor head about two orthogonal axes. The Arizona imager/spectrograph is designed for investigations of the interaction between the Space Shuttle and its environment. It is scheduled for flight on a Shuttle subsatellite.

Broadfoot, A. L.↗

NASA NTRS1979

EUV observations of the equatorial aurora

Using the Apollo-Soyuz mission's extreme ultraviolet telescope, it proved possible to observe the equatorial aurora on four different occasions. The observations were made from 220 km in quiet geomagnetic conditions. In all cases, signals were well above ambient background in the 50 to 150 A, 114 to 150 A, 170 to 600 A, and 500 to 780 A bands. The existence of a strong feature in the 50 to 150 A region may be an indication that other elements besides helium - possibly oxygen and nitrogen - contribute to the enhancement.

Paresce, F.↗

NASA NTRS1989

A comparison of reflector antenna designs for wide-angle scanning

Conventional reflector antennas are typically designed for up to + or - 20 beamwidths scan. An attempt was made to stretch this scan range to some + or - 300 beamwidths. Six single and dual reflector antennas were compared. It is found that a symmetrical parabolic reflector with f/D = 2 and a single circular waveguide feed has the minimum scan loss (only 0.6 dB at Theta sub 0 = 8 deg, or a 114 beamwidths scan). The scan is achieved by tilting the parabolic reflector by an angle equal to the half-scan angle. The f/D may be shortened if a cluster 7 to 19 elements instead of one element is used for the feed. The cluster excitation is adjusted for each new beam scan direction to compensate for the imperfect field distribution over the reflector aperture. The antenna can be folded into a Cassegrain configuration except that, due to spillover and blockage considerations, the amount of folding achievable is small.

Zimmerman, M.↗

NASA NTRS1989

A comparison of reflector antenna designs for wide-angle scanning

Conventional reflector antennas are typically designed for up to + or - 20 beamwidths scan. An attempt was made to stretch this scan range to some + or - 300 beamwidths. Six single and dual reflector antennas were compared. It is found that a symmetrical parabolic reflector with f/D = 2 and a single circular waveguide feed has the minimum scan loss (only 0.6 dB at Theta sub 0 = 8 deg, or a 114 beamwidths scan). The scan is achieved by tilting the parabolic reflector by an angle equal to the half-scan angle. The f/D may be shortened if a cluster 7 to 19 elements instead of one element is used for the feed. The cluster excitation is adjusted for each new beam scan direction to compensate for the imperfect field distribution over the reflector aperture. The antenna can be folded into a Cassegrain configuration except that, due to spillover and blockage considerations, the amount of folding achievable is small.

Zimmerman, M.↗

NASA NTRS2023

Distributions of Mesoscale Periodic Structures in the Elemental and Ionic Composition of the Solar Wind

Multiple statistical and event studies based on in situ observations have shown that the solar wind contains mesoscale (∼ 100 – 10,000 Mm) periodic structures in the proton number density. Remote observations of such structures and event studies of concurrent variations in composition have demonstrated that they can form in the solar atmosphere and be preserved while advecting outwards through the heliosphere. Viall, Kepko, and Spence (J. Geophys. Res. (Space Phys.) 113, A07101, 2008; J. Geophys. Res. (Space Phys.) 114, A01201, 2009) and Kepko, Viall, and Wolfinger (J. Geophys. Res. (Space Phys.) 125(8), e28037, 2020) have reported that periodic proton density structures preferentially occur at specific radial length scales and have published their distributions from Wind measurements near L1. Here, we conduct a statistical study of 14 years (1998 – 2011) of 12-minute composition data measured by the Solar Wind Ion Composition Spectrometer instrument aboard the Advanced Composition Explorer spacecraft. We found that the elemental and ionic composition also contain statistically significant mesoscale periodic structures and, for the first time, present occurrence distributions for elemental abundance ratios with low, intermediate, and high first ionization potentials as well as for key solar wind charge states. These distributions set important constraints on solar wind formation in general and the formation of periodic mesoscale solar wind structures specifically, as the elemental and ionic composition are known to be determined at the Sun and to not evolve during advection.

Solar wind↗

NASA NTRS2022

Determining Latitudinal Extent of Energetic Electron Precipitation Using MEPED On-Board NOAA/POES

Energetic Electron Precipitation (EEP) from the plasma sheet and the radiation belts ionizes the polar lower thermosphere and mesosphere. EEP increases the production of NO x and HO x , which will catalytically destroy ozone, an important element of atmospheric dynamics. Therefore, measurement of the latitudinal extent of the precipitation boundaries is important in quantifying the atmospheric effects of the Sun-Earth interaction. This study uses measurements by the Medium Energy Proton Electron Detector (MEPED) of six NOAA/POES and EUMETSAT/METOP satellites from 2004 to 2014 to determine the latitudinal boundaries of EEP and their variability with geomagnetic activity and solar wind drivers. Variation of the boundaries for different electron energies and Magnetic Local Time (MLT) is studied. Regression analyses are applied to determine the best predictor variable based on solar wind parameters and geomagnetic indices. The highest correlation was found for the pressure-corrected Dst index when applying a linear regression model. A model of the equatorward EEP boundary is developed separately for three different energy channels, >43, >114, and >292 keV, and for 3 hour MLT sectors. For >43 keV EEP, 80% of the equatorward boundaries predicted by the model are within ±2.2° cgmlat. The model exhibits a solar cycle bias where it systematically exaggerates the equatorward movement of the EEP region during solar minimum. The highest accuracy of the model is found in periods dominated by corotating interaction regions/high speed solar wind streams. The result will be a key element for constructing a model of EEP variability to be applied in atmosphere climate models.

E. M. Babu↗

NASA NTRS1995

Technical Reports: Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants.

Schwan, Rafaela↗

NASA NTRS1995

Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants.

Schwan, Rafaela↗

NASA NTRS1994

NASA's Microgravity Science Program

Since the late 1980s, the NASA Microgravity Science Program has implemented a systematic effort to expand microgravity research. In 1992, 114 new investigators were selected to enter the program and more US microgravity experiments were conducted in space than in all the years combined since Skylab (1973-74). The use of NASA Research Announcements (NRA's) to solicit research proposals has proven to be highly successful in building a strong base of high-quality peer-reviewed science in both the ground-based and flight experiment elements of the program. The ground-based part of the program provides facilities for low gravity experiments including drop towers and aircraft for making parabolic flights. Program policy is that investigations should not proceed to the flight phase until all ground-based investigative capabilities have been exhausted. In the space experiments program, the greatest increase in flight opportunities has been achieved through dedicated or primary payload Shuttle missions. These missions will continue to be augmented by both mid-deck and GAS-Can accommodated experiments. A US-Russian cooperative flight program envisioned for 1995-97 will provide opportunities for more microgravity research as well as technology demonstration and systems validation efforts important for preparing for experiment operations on the Space Station.

Salzman, Jack A.↗