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Wade, T. L.

Publications and source records attributed to Wade, T. L..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

An uranyl sorption study inside functionalised nanopores

Sorption mechanism of uranyl by poly(bis[2-(methacryloyloxy)ethyl] phosphate) (PB2MP) functionalised polyvinylidene fluoride (PVDF) track-etched membranes, PB2MP-g-PVDF, was investigated. It was found that uranyl sorption obeyed Langmuir isotherm model giving a maximum U(VI) membrane uptake of 6.73 μmol g -1 and an affinity constant of 9.85 10 6 L mol -1 . XPS and TRPL measurements were performed to identify sorbed uranyl oxidation state and its environment. Uranyl was found to be mainly in its hexavalent state, i.e. U(VI), showing that the trapping inside the PB2MPg-PVDF nanoporous membranes did not change the ion speciation. Two sorbed uranyl life-times ($τ_1$ = 8.8 μs and $τ_2$ = 102.8 μs) were measured by TRPL which pointed out different complexations taking place inside the nanopores. Uranyl sorption by PB2MP-g-PVDF membranes was also found to be pH dependent demonstrating the highest performance at circumneutral pH. In addition, TRPL was demonstrated to be not only a remarkable technique for U(VI) characterization, but also an alternative to voltammetry detection for trace on-site uranyl monitoring using PB2MP-g-PVDF nanoporous membranes

36 MATERIALS SCIENCE↗
NASA NTRS1981

The relationship among sea surface roughness variations, oceanographic analyses, and airborne remote sensing analyses

The synthetic aperture radar (SAR) was studied to determine whether it could image large scale estuaries and oceanic features such as fronts and to explain the electromagnetic interaction between SAR and the individual surface front features. Fronts were observed to occur at the entrance to the Chesapeake Bay. The airborne measurements consisted of data collection by SAR onboard an F-4 aircraft and real aperture side looking radar (SLAR) in Mohawk aircraft. A total of 89 transects were flown. Surface roughness and color as well as temperature and salinity were evaluated. Cross-frontal surveys were made. Frontal shear and convergence flow were obtained. Surface active organic materials, it was indicated, are present at the air-sea interface. In all, 2000 analyses were conducted to characterize the spatial and temporal variabilities associated with water mass boundaries.

Oertel, G. F.↗
NASA NTRS1981

Concentration of hydrocarbons associated with particles in the shelf waters adjacent to the entrance of Chesapeake Bay

Particulate hydrocarbon concentrations were measured in 94 water samples. The concentrations ranged from below the detection limit ( 0.7 micro-G/L) to 32 micro-g/l. The mean for all samples was 5.6 micro-g/l. Particulate hydrocarbon concentrations are higher in the Bay mouth and lower in the shelf waters adjacent to the entrance of Chesapeake Bay. No coherent particulate hydrocarbon distribution is seen with depth in the water column. The Bay is postulated as one of the possible chronic sources of particulate hydrocarbons for the adjacent shelf waters.

Wade, T. L.↗
NASA NTRS1981

Coprostanol as a potential tracer of particulate sewage effluent to shelf waters adjacent to the Chesapeake Bay

Samples were collected in the Chesapeake Bay entrance and contiguous shelf waters and were subsequently analyzed for particulate coprostanol and cholesterol concentrations. Surface coprostanol concentrations were fairly uniform, with a slight increase with depth. This increase with depth may be due to sewage-associated particulates settling as they leave the Bay, or the resuspension of contaminated sediment. Preliminary findings indicate sewage-associated materials are being transported from the Chesapeake Bay to shelf waters, where they may have a detrimental affect on living marine resources.

Brown, R. C.↗