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The hygienic risk associated with evaporative cooling systems in Germany is currently only assessed by determining concentrations of Legionella spp. in the corresponding cooling waters. Relevant for the health risk is however the load of Legionella in emitted aerosols. In this work aerosol emissions from four industrial cooling systems (A - D) were analyzed. A microbiological air bioburden factor (MABF) is suggested to be useful to assess the overall microbiological load of emitted air and to judge the efficiency of droplet separation and overall microbiological retention. Whereas the MABF by itself only serves as a technical quality assurance (QA) parameter, the hygienic relevance has to be seen in combination with the assessment of Legionella either contained in the aerosol or in the cooling water. Plate counting of colonies was an appropriate method to quantify Legionella spp. in aerosols given the short time of flight at the chosen sampling locations and resulting low risk of desiccation. qPCR data on the other hand proved more reproducible than the culture approach to quantify Legionella spp. concentrations in cooling water-. The application of qPCR also allowed to assess the relative proportion of Legionella pneumophila within the total pool of Legionella which adds epidemiological relevance to risk assessment. A traffic light system was proposed to guide interpretation of qPCR data. The four industrial systems greatly differed in all measured parameters leading to different associated risks.

Pentalene bridged zirconocene/methylaluminoxane catalysts are described as useful for the polymerization of ethene, propene, and co-polymerizations with norbornene. They show a high thermostability up to polymerization temperatures of 105 °C. Polyethylenes with molecular masses of 4 million g/mol are obtained at 30 °C and 500,000 g/mol at more than 90 °C. The molecular mass distribution varies between 2 and 15 because of the steric isomers of the pentalene ligand. Some of the complexes are active for the polymerization of propene. Similar to ansa cyclopentadienyl–fluorenyl complexes, the tacticity of the produced polypropylenes can be changed from syndiotactic to isotactic by substitution of the cyclopentadienyl ring.

Solution and gas phase processes of the polymerization of ethene are compared using new types of pentalenyl bridged ansa-metallocenes such as [Me 3 Pen(Flu)]ZrCl 2 . As of the bridge, the catalyst system is remarkable thermostable up to 105 °C and a deactivation of the metallocene on the silica support can be suppressed. Compared to the non-supported catalyst in a solution process, the application of the heterogenized system in a gas phase process leads to a decrease in activities while molar masses of the polyethenes are similar. Due to a higher degree of short chain branches of 20-30 per 1 000 carbon atoms instead of 10-17, the melting temperatures are 10 °C lower than those for polymers obtained in the solution process.