Recommendations and comments concerning documentation on the microwave active spectrometer systems

There are no author-identified significant results in this report

Scatterometer receiver dynamic range/linearity

Results of an investigation aimed at determining the dynamic range and linearity of the S-193 scatterometer receiver from data acquired during Skylab missions 2 and 3 are summarized

Accomplishments of the NASA Johnson Space Center portion of the soil moisture project in fiscal year 1981

The NASA/JSC ground scatterometer system was used in a row structure and row direction effects experiment to understand these effects on radar remote sensing of soil moisture. Also, a modification of the scatterometer system was begun and is continuing, to allow cross-polarization experiments to be conducted in fiscal years 1982 and 1983. Preprocessing of the 1978 agricultural soil moisture experiment (ASME) data was completed. Preparations for analysis of the ASME data is fiscal year 1982 were completed. A radar image simulation procedure developed by the University of Kansas is being improved. Profile soil moisture model outputs were compared quantitatively for the same soil and climate conditions. A new model was developed and tested to predict the soil moisture characteristic (water tension versus volumetric soil moisture content) from particle-size distribution and bulk density data. Relationships between surface-zone soil moisture, surface flux, and subsurface moisture conditions are being studied as well as the ways in which measured soil moisture (as obtained from remote sensing) can be used for agricultural applications

Analysis of Jovian decametric data: Study of radio emission mechanisms

The Voyager 1 and Voyager 2 Planetary Radio Astronomy Experiments (PRA) have produced the finest set of Jovian decametric radio emission data ever obtained. Jovian decametric L-burst and S-burst arcs were characterized and the data reconciled with models for the radio emission geometry and mechanisms. The first major results involve comparisons of the distribution of arc separations with longitudes. The identification and analyses of systematic variations in the PRA data have yielded interesting results, but only the most obvious features of the data were examined. Analyses of the PRA data were extended with the use of new 6-Sec formats that are more sensitive to the S-bursts

Analysis of Jovian decamteric data: Study of radio emission mechanisms

This research effort involved careful examination of Jovian radio emission data below 40 MHz, with emphasis on the informative observations of the Planetary Radio Astronomy experiment (PRA) on the Voyager 1 and 2 spacecraft. The work is divided into three sections, decametric arcs, decametric V bursts, and hectometric modulated spectral activity (MSA)

High spatial resolution passive microwave sounding systems

Two extensive series of flights aboard the ER-2 aircraft were conducted with the MIT 118 GHz imaging spectrometer together with a 53.6 GHz nadir channel and a TV camera record of the mission. Other microwave sensors, including a 183 GHz imaging spectrometer were flown simultaneously by other research groups. Work also continued on evaluating the impact of high-resolution passive microwave soundings upon numerical weather prediction models

Experimental investigation of self coherent optical OFDM systems using fabry-perot filters for carrier extraction

We experimentally demonstrate self coherent optical OFDM transmission with IQ demultiplexing employing a Fabry-Perot-tunable filter for the extraction of the optical carrier. The performance is investigated and compared to a conventional CO-OFDM

Electron-phonon coupling in the conventional superconductor YNi2_2B2_2C at high phonon energies studied by time-of-flight neutron spectroscopy

We report an inelastic neutron scattering investigation of phonons with energies up to 159 meV in the conventional superconductor YNi$_2$B$_2$C. Using the SWEEP mode, a newly developed time-of-flight technique involving the continuous rotation of a single crystal specimen, allowed us to measure a four dimensional volume in (Q,E) space and, thus, determine the dispersion surface and linewidths of the $A_{1g}$ (~ 102 meV) and $A_u$ (~ 159 meV) type phonon modes for the whole Brillouin zone. Despite of having linewidths of $\Gamma = 10 meV$, $A_{1g}$ modes do not strongly contribute to the total electron-phonon coupling constant $\lambda$. However, experimental linewidths show a remarkable agreement with ab-initio calculations over the complete phonon energy range demonstrating the accuracy of such calculations in a rare comparison to a comprehensive experimental data set.Comment: accepted for publication in PR

Constructions of free commutative integro-differential algebras

In this survey, we outline two recent constructions of free commutative integro-differential algebras. They are based on the construction of free commutative Rota-Baxter algebras by mixable shuffles. The first is by evaluations. The second is by the method of Gr\"obner-Shirshov bases.Comment: arXiv admin note: substantial text overlap with arXiv:1302.004

Radio Astronomy

Contains reports on six research projects.National Aeronautics and Space Administration (Grant NsG-419)National Aeronautics and Space Administration (Contract NSR-22-009-120