<Superscript>210</Superscript>Pb and <Superscript>210</Superscript>Po in fossil fuel combustion at the Šoštanj thermal power plant (Slovenia)

The main aim of the present study was to evaluate ²¹⁰Pb and ²¹⁰Po emissions from the ?o?tanj TPP and to evaluate their mass balance in unit 4. Samples of coal, fly ash, slag and flue gases were analysed for ²¹⁰Pb and ²¹⁰Po content. The results showed that these radionuclides are mostly concentrated in ash (71% and 81% for ²¹⁰Pb and ²¹⁰Po, respectively). Only a small part of the input activity was detected in flue gases. The activities of ²¹⁰Pb and ²¹⁰Po in unit 4 were from 1.1 to 2.7 Bq m^?3 and from 0.37 to 0.56 Bq m^?3, respectively. The mass balance of the two radionuclides in unit 4 show only 6 and 10% differences between the annual activities of the input and output samples.     

234U and 238U in mineral water: reference value and uncertainty evaluation in the frame of an interlaboratory comparison

In 2007/2008 the Institute for Reference Materials and Measurements (IRMM) organised an interlaboratory comparison (ILC) on the determination of ²²⁶Ra, ²²⁸Ra, ²³⁴U and ²³⁸U activity concentrations in mineral water. This paper describes the determination of the reference values for the activity concentrations of ²³⁴U and ²³⁸U by radiochemical separation and α-particle spectrometry performed at two independent laboratories. The experimental uncertainty of the reference values is discussed in detail.     

Über die Infrarotspektren einiger Metallkomplexe des Mono- und Dimethylolharnstoffes

Coordination products of mono- and dimethyl-urea were synthesised with salts of copper, manganese, cobalt, nickel, and zink and their infrared spectra were obtained. By comparison with the pure ligands spectra it was established that the coordination with metals is accomplished through the carbonyl group oxygen.     

Models of Self-Financing Hedging Strategies in Illiquid Markets: Symmetry Reductions and Exact Solutions

We study the general model of self-financing trading strategies in illiquid markets introduced by Schönbucher and Wilmott (SIAM J Appl Math 61(1):232?C272, 2000). A hedging strategy in the framework of this model satisfies a nonlinear partial differential equation (PDE) which contains some function g(??). This function is deeply connected to a marginal utility function. We describe the Lie symmetry algebra of this PDE and provide a complete set of reductions of the PDE to ordinary differential equations (ODEs). In addition, we show the way how to describe all types of functions g(??) for which the PDE admits an extended Lie group. Two of these special type functions correspond to the models introduced before by different authors, whereas one is new. We clarify the connection between these three special models and the general model for trading strategies in the illiquid markets. We also apply the Lie group analysis to the new special case of the PDE describing the self-financing strategies. For the general model, as well as for the new special model, we provide the optimal systems of subalgebras and study the complete set of reductions of the PDEs to ODEs. We provide explicit solutions to the new special model in all reduced cases. Moreover, in one of the cases the solutions describe power derivative products.     

Experimental investigation of integral and local flow field properties on rotating porous disc

Flow field through rotating porous disc was investigated with experimental fluid dynamics and compared with computational fluid dynamics. Open cell aluminum metal foam with 88% porosity was used. On rotating porous disc, integral measurements of static pressure difference in dependence of air volume flow rate were performed. Local measurements of velocity profiles close to disc circumference were performed with hot-wire anemometry. The airflow visualization method using smoke generator and digital camera was performed. Flow structures through porous disc were visualized at three different air volume flow rates. Numerical simulation of homogenous rotating porous disc was performed. Experimental and numerical results were compared. The results showed appropriate comparison of integral and local properties. The presented experimental approach can be used for the investigation and understanding of flow field phenomena on rotating porous materials. The proposed conclusions can be applied for variable applications on rotating porous materials.     

Reactions of triethylgermylpentafluorobenzene with some electrophilic agents

Triethylgermylpentafluorobenzene C₆F₅GeEt₃ reacts with CF₃SO₃H, HSO₃Cl, Me₃SiOSO₂Cl, chlorine, bromine, Cl₂/AlCl₃, or Br₂/AlBr₃ with cleavage of the C_aryl Ge bond. Cesium fluoride promotes electrophilic degermylation of C₆F₅GeEt₃, possibly via the intermediate formation of a tetraorganylfluorogermanate.