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Quantum Irreversibility and Chaos [Phys. Rev. Lett. 67, 2593 (1991)] (open access)

Quantum Irreversibility and Chaos [Phys. Rev. Lett. 67, 2593 (1991)]

Corrections to an equation printed with a typographical error in Quantum Irreversibility and Chaos, Physical Review Letters 67, 2593 (1991).
Date: December 23, 1991
Creator: Bonci, Luca; Roncaglia, Roberto; West, Bruce J. & Grigolini, Paolo
System: The UNT Digital Library
Partitioning between sediment and porewater of radiocesium from Chernobyl fallout (open access)

Partitioning between sediment and porewater of radiocesium from Chernobyl fallout

As part of a joint USA/USSR Environmental Agreement to determine the distribution and concentration of Chernobyl radioactivity in the northwest Black Sea area, the sediment from eight stations was collected and analyzed to assess the ability of sediment from the northwest Black Sea to adsorb radiocesium. Two methods were used to determine partitioning between liquid and solid phases; batch tests and porewater separation. In the batch test, Cs-137 tracer was added to mixtures of sediment and bottom water, with contact solutions ranging from 85 Bq/ml to 1760 Bq/ml. The distribution ratios (R{sub D}) for individual batch tests ranged from 390 to 1770 ml/g. Isotherms were linear for all cores and R{sub D} values calculated from the slopes of the isotherms ranged from 660 to 1660 ml/g. A second approach was used to determine the partitioning of Cs-137 between the porewater and the sediment under more natural conditions. The top 2 cm of two cores were sectioned and the sediment and the porewater were separated. In both samples the sediment contained significant amounts of Cs-137 and Cs-134 indicating the presence of fallout from the Chernobyl reactor accident. There was no cesium activity observed in the porewater at a minimum detectable level …
Date: April 23, 1991
Creator: Fuhrmann, M.; Pietrzak, R. (Brookhaven National Lab., Upton, NY (USA)); Neiheisel, J. & Dyer, R. (Environmental Protection Agency, Washington, DC (USA))
System: The UNT Digital Library
The AGS Booster high frequency rf system (open access)

The AGS Booster high frequency rf system

A high level rf system, including a power amplifier and cavity, has been designed and built for the AGS Booster. It covers a frequency range of 2.4 to 4.2 MHz and will be used to accelerate high intensity protons. Low intensity polarized protons and heavy ions, to the 1.5 GeV level. A total accelerating voltage of up to 90 kV will be provided by two cavities, each having two gaps. The internally cross coupled, pushpull cavities are driven by an adjacently located power amplifier. In order to accommodate beam intensities up to 0.75 {times} 10{sup 13} protons per bunch, a low plate resistance power tetrode is used. The tube anode is magnetically coupled to one of the cavity's two parallel cells. The amplifier is a grounded cathode configuration driven by a remotely located solid-state amplifier. It has been tested in the laboratory at full gap voltage with satisfactory results. 5 refs., 2 figs., 1 tab.
Date: April 23, 1991
Creator: Sanders, R.T.; Cameron, P.; Eng, W.; Goldman, M.A.; Jablonski, E.; Kasha, D. et al.
System: The UNT Digital Library