Radiometrische lsotopenhäufigkeitsanalyse von 233^{233}U_235^{235}U-Gemischen

Es wird ein radiometrisches Abbrand-Analysenverfahren beschrieben, das eine zuverlässige Isotopenhäufigkeitsbestimmung von $^{233}$U_$^{235}$U-Gemischen gestattet. Man mißt dazu das in der zu analysierenden Uranprobe durch thermische Kernspaltung induzierte Radioaktivitätsverhältnis zweier Spaltnuklide, deren Spaltausbeuten wesentlich verschieden für die beiden Uranisotope sind. Durch Vergleich mit reinen $^{233}$U- und $^{235}$U-Standards, die unter identischen Bedingungen mitbestrahlt werden, läßt sich der unbekannte Gehalt an $^{233}$U bzw. $^{235}$U in der Analysenprobe ermitteln. Zwei Spaltausbeute-Verhältnisse,nämlich das von $^{103}$Ru/$^{89}$Sr und $^{103}$Ru/$^{131}$J eignen sich besonders gut für diesen Zweck. Außerdem läßt sich in den Uranproben gleichzeitig der Gehalt an $^{238}$U über die Messung der (n, $\gamma$)-induzierten $^{239}$Np-Aktivität ermitteln

Papierelektrophoretische Trennung von Thorium, Protaktinium und Uran

A simple electrophoretic procedure for the separation and determination of thorium, protactinium and uranium is described, based on the different migration velocities of the oxalate complexes of the three elements in an electric field. Their quantitative separation is achieved using a 0.12 M ammonium oxalate electrolyteapplying a potential gradient of 16 V/cm for two hours. The anionic migration of the metal oxalate complexes increases in the order Th, Pa, U

The pricing of water in a university town: An economic analysis of draining a cash cow

This paper analyzes some economic issues involved with the common practice of using metered water rate revenue to fund debt retirement associated with the provision of municipal water and wastewater services. We conclude that rather than simply raising the metered rate, city officials should seriously consider increasing the tax rate levied under the local property tax. There is an important trade-off in the choice of a price policy. An increased property tax rate can result in tax savings to some home owners, which lowers their net expenditure for water. However, a corresponding decrease in the metered rate may increase water consumption, which in turn raises operating cost. In order to do what is best for home owners, it might make sense to give other customers (e.g., a university) an easy ride, even if the latter, because of its low (inelastic) price elasticity of demand for water, is viewed by the municipality as a cash cow

Modelling the runoff response in the Mulde catchment (Germany)

International audienceThe paper presents two different levels of regionalization used to represent the spatial distribution of landscape parameters for the hydrological modelling of the Mulde. The aim of this investigation was to find out how the discretisation level affects quality of modelling with the hydrological modelling system J2000. Furthermore we improved our understanding of the applicability and reliability of the distributed model J2000 on the macro-scale. Spatial information was aggregated in two different discretisation levels: subbasins (SB) and hydrological response polygons (HRP). A J2000 simulation was carried out for both discretisation levels based on a 1 year calibration and a 3 year validation period. Simulations performed well for both levels of spatial discretisation. The results seemed to be better in the more complex discretisation approach, where the Nash-Sutcliffe coefficient was higher. We can conclude that our first results show more accurate simulations produced by the HRP discretisation approach, the visual inspection shows a better application of the SB approach to the reproduction of the base flow

Leonore Polka

https://digitalcommons.library.umaine.edu/mmb-ps/3392/thumbnail.jp