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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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This paper describes the performance of planar back-to-back Barrier-N-N(sup +)(bbBNN) devices for millimeter and submillimeter wave multiplier applications.
A frequency tripler has been developed using an integrated planar back-to-back -n-n(sup +) varactor device in a waveguide mount at 220 GHz.
It has been predicted that the heat capacity of superfluid (sup 4)He will diverge strongly at a depressed transition temperature in the presence of a constarant heat current, Q.
Measurements of line positions and absolute strengths of D(sub 2)O from 700 to 3100 cm(sup )-1 were obtained with a Fourier transform spectrometer.
The Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator (MAS) and MODIS/Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Airborne Simulator (MASTER) were used to obtain measurements of the bidirectional reflectance and brightness temperature of clouds at 50 discrete wavelengths between 0.47 and 14.2 microns (12.9 microns for MASTER). These observations were obtained from the NASA ER-2 aircraft as part of the Tropical Composition, Cloud and Climate Coupling (TC4) experiment conducted over Central America and surrounding Pacific and Atlantic Oceans between 17 July and 8 August 2007. Multispectral images in eleven distinct bands were used to derive a confidence in clear sky (or alternatively the probability Of cloud) over land and ocean ecosystems. Based on the results of individual tests run as part of the cloud mask, an algorithm was developed to estimate the phase of the clouds (liquid water, ice, or undetermined phase). The cloud optical thickness and effective radius were derived for both liquid water and ice clouds that were detected during each flight, using a nearly identical algorithm to that implemented operationally to process MODIS Cloud data from the Aqua and Terra satellites (Collection 5). This analysis shows that the cloud mask developed for operational use on MODIS, and tested using MAS and MASTER data in TC(sup 4), is quite capable of distinguishing both liquid water and ice clouds during daytime conditions over both land and ocean. The cloud optical thickness and effective radius retrievals use five distinct bands of the MAS (or MASTER), and these results were compared with nearly simultaneous retrievals of marine liquid water clouds from MODIS on the Terra spacecraft. Finally, this MODIS-based algorithm was adapted to Multiangle Imaging SpectroRadiometer (MISR) data to infer the cloud optical thickness Of liquid water clouds from MISR. Results of this analysis are compared and contrasted.
One of the main goals of the Tropical Composition, Cloud and Climate Coupling Experiment (TC(sup 4)) during July and August 2007 was to gain a better understanding of the formation and life cycle of cirrus clouds in the upper troposphere and lower stratosphere and how their presence affects the exchange of water vapor between these layers. Additionally, it is important to compare in situ measurements taken by aircraft instruments with products derived from satellite observations and find a meaningful way to interpret the results. In this study, cloud properties derived using radiance measurements from the Geostationary Operational Environmental Satellite (GOES) imagers are compared to similar quantities from aircraft in situ observations and are examined for meaningful relationships. A new method using dual \angle satellite measurements is used to derive the ice water content (IWC) for the top portion of deep convective clouds and anvils. The results show the in situ and remotely sensed mean microphysical properties agree to within approx.10 microns in the top few kilometers of thick anvils despite the vastly different temporal and spatial resolutions of the aircraft and satellite instruments. Mean particle size and IWC are shown to increase with decreasing altitude in the top few kilometers of the cloud. Given these relationships, it may be possible to derive parameterizations for effective particle size and IWC as a function of altitude from satellite observations
Human immune response is compromised and bacteria can become more antibiotic resistant in space microgravity (MG). We report that under low-shear modeled microgravity (LSMMG) stationary-phase uropathogenic Escherichia coli (UPEC) become more resistant to gentamicin (Gm). UPEC causes urinary tract infections (UTIs), reported to afflict astronauts; Gm is a standard treatment, so these findings could impact astronaut health. Because LSMMG has been shown to differ from MG, we report here preparations to examine UPEC's Gm sensitivity during spaceflight using the E. coli Anti-Microbial Satellite (EcAMSat) on a free flying nanosatellite in low Earth orbit. Within EcAMSats payload, a 48-microwell fluidic card contains and supports study of bacterial cultures at constant temperature; optical absorbance changes in cell suspensions are made at three wavelengths for each microwell and a fluid-delivery system provides growth medium and predefined Gm concentrations. Performance characterization is reported for spaceflight prototypes of this payload system. Using conventional microtiter plates, we show that Alamar Blue (AB) absorbance changes due to cellular metabolism accurately reflect E. coli viability changes: measuring AB absorbance onboard EcAMSat will enable telemetry of spaceflight data to Earth. Laboratory results using payload prototypes are consistent with wellplate and flask findings of differential sensitivity of UPEC and its delta rpoS strain to Gm. Space MG studies using EcAMSat should clarify inconsistencies from previous space experiments on bacterial antibiotic sensitivity. Further, if sigma (sup s) plays the same role in space MG as in LSMMG and Earth gravity, EcAMSat results would facilitate utilizing our previously developed terrestrial UTI countermeasures in astronauts.
Delayed γ-ray spectroscopy of 185Au was studied at the Argonne Gas-Filled Analyzer. A new isomer at an excitation energy of 1504.2(4) keV with a half-life of 630(80) ns was identified via γ-γ coincidence analysis, decaying via a 294.8(3) keV transition. Based on Weisskopf estimates, the multipolarity of the 295 keV transition is assigned to be E1, M1, E2, or M2. Possible configurations for this new isomer are discussed based on configuration-constrained potential energy surface calculations.
The intruder bands in Sn isotopes, built on the 2p-2h excitation across the Z = 50 proton shell gap, are well-known examples of shape coexistence near the neutron mid-shell region. Spectroscopic signatures for shape coexistence include enhanced E0 transitions between the 0+ band heads. However, the underlying shape coexistence and mixing has been unclear because lifetime information for the excited 0+ states was incomplete in 118Sn. We thus present here the first measurement of the 0+ 3 lifetime in 118Sn using the fast-timing technique following thermal-neutron capture. The observed enhancement in ρ2(E0;0+ 3 → 0+ 2 ) of 150(30) milliunits provides compelling indications for multiple shape coexistence in 118Sn. Additionally, three distinct shapes in 116,118,120Sn naturally emerged in theoretical calculations based on the quantum-number-projected generator coordinate method employing a relativistic energy density functional.
Excited levels in 111−121 Ag , odd-𝐴 isotopes populated following spontaneous fission of 252 Cf have been studied using high-fold 𝛾 coincidences measured with Gammasphere array of Compton-suppressed Ge spectrometers at Argonne National Laboratory. The experimental information on these nuclei reported before has been corrected and extended. In the work we discuss the evolution of triaxiality in odd-Ag nuclei. Relative positions of the 𝜋𝑝1/2 and 𝜋𝑔9/2 shells defining the 𝑍=40 gap when approaching the 𝑁=82 closure, the 𝜋1/2+[431] intruder bands, the three-quasiparticle configurations, and the so called 𝑗−1 anomaly in odd-Ag nuclei are also discussed.
Photolysis of mixtures of oxygen with nitrous oxide, nitrogen, and carbon dioxide, and relative reaction rates of 1 D oxygen atoms with admixed gases
Neutron irradiation effects on embrittlement of polycrystalline tungsten
Scanning celestial attitude determination system for small scientific satellites
Eigenvalves of dynamic spin Hamiltonian for trivalent iron ion in titanium dioxide host crystals - tables
Small Scientific Satellite program and first payload considerations
FORTRAN 4 subroutines for calculating critical flow factor to determine mass flow rate of gaseous helium and nitrogen through critical flow nozzles
Plastic deformation of corrosion resistant steel, CER-VIT 101, and fused silica as function of applied torsional stress
Tabulation of matrix elements of atomic interaction operators for various configurations