Absorption in the ν3 Band of UF6 Dissolved in Solid Xenon

The ν₃ band of UF₆ isolated in solid xenon is shown to consist of a single sharp spectral feature.     

Zur Bestimmung der Salpeters?ure

Ohne Zusammenfassung     

Acoustic scattering from mud volcanoes and carbonate mounds

Submarine mud volcanoes occur in many parts of the world's oceans and form an aperture for gas and fluidized mud emission from within the earth's crust. Their characteristics are of considerable interest to the geology, geophysics, geochemistry, and underwater acoustics communities. For the latter, mud volcanoes are of interest in part because they pose a potential source of clutter for active sonar. Close-range (single-interaction) scattering measurements from a mud volcano in the Straits of Sicily show scattering 10-15 dB above the background. Three hypotheses were examined concerning the scattering mechanism: (1) gas entrained in sediment at/near mud volcano, (2) gas bubbles and/or particulates (emitted) in the water column, (3) the carbonate bio-construction covering the mud volcano edifice. The experimental evidence, including visual, acoustic, and nonacoustic sensors, rules out the second hypothesis (at least during the observation time) and suggests that, for this particular mud volcano the dominant mechanism is associated with carbonate chimneys on the mud volcano. In terms of scattering levels, target strengths of 4-14 dB were observed from 800 to 3600 Hz for a monostatic geometry with grazing angles of 3-5 degrees. Similar target strengths were measured for vertically bistatic paths with incident and scattered grazing angles of 3-5 degrees and 33-50 degrees, respectively.     

Phase Development in Sol Derived Microporous Membranes for Gas Permselectivity

A sol-gel route has been used to produce a nanoporous membrane for the separation of greenhouse gases from power plants at elevated temperatures (700–900 K). The membrane has a controlled pore size distribution and is multiphasic, in order to prevent grain growth and pore coarsening. The alumina/titania diphasic ceramic was obtained from alkoxide precursors with additional magnesium or lanthanum doping to stabilize low temperature phases and to provide possible chemisorption of CO2. It was found that both Mg and La stabilized the -alumina phase to higher temperature by as much as 200 K, although Mg is less effective.