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Institute
Strukturierte Feinbleche werden seit etwa 2 Jahrzehnten vor allem in der Automobilindustrie als Wärmeabschirmbleche und Abgasanlagenverkleidungen
eingesetzt. Weitere Anwendungen sind gestaltete Oberflächen, C – Profile für Trockenbauwände, Kuchenformen usw. Eine Strukturierung wird oft dort eingesetzt, wo ein sich anschließender Umformvorgang zu Faltenbildung führen
würde. Durch die Strukturierung treten diese Falten optisch nicht übermäßig in Erscheinung. Dabei wird das besondere Leichtbaupotential dieser strukturierten
Bleche meist nicht ausgenutzt. Sie weisen nämlich eine deutlich größere Biegesteifigkeit als glatte Feinbleche gleicher Blechstärke auf. Untersuchungen mit verschiedenen strukturierten Blechen zeigten, dass bei einigen Strukturen für die gleiche Durchbiegung im Biegeversuch annähernd die doppelte Kraft gegenüber glatten Blechen gleicher Ausgangsblechstärke aufgewendet werden muss. Darin liegt nun das Leichtbaupotential, sofern es
keine geometrischen Einschränkungen bezüglich des Bauraumes gibt, da natürlich das strukturierte Blech zwar nicht Volumenmäßig sondern eher Einbauraummäßig mehr Bauraum beansprucht. Das strukturierte Blech kann etwa in der halben Ausgangsblechstärke gegenüber dem Glattblech ausgeführt werden.
The publishers are receiving more and more inquiries about the topic “Floating Architecture”, particularly about technical details, water chemistry, as well as ice and wave problems. Since there is a lack of technical literature on this topic, most students working on projects or theses related to this topic send their inquiries. A time of general and quick changes results in a large number of daily publications. Therefore it is difficult to understand why there is a lack of lit-erature about floating structures. One has to consider that sea levels will continue to rise and consequently a larger number of people will have to live on the surface of the sea. Obviously, some expert knowledge is required which needs a longer period of time to be gained through scientific advancements and experience. The publishers, who have been dealing with the topic of floating houses for some years, are grateful to the authors for their agreement to allow the publication of their papers on floating architecture. These papers were mainly prepared for two conferences on floating architecture held in the study centre of the IBA building, Großräschen. Therefore, the reader should know that, along with the usual papers, only a selection of self-explaining transparencies is shown in order to meet the printing requirements. The included list of both the authors and their addresses makes it easy for interested people to send any inquiries to them. A short introduction as well as an outlook at the end of each paper is meant to draw attention to current events in order to be able to promptly identify opportunities and risks connected with living on the water.
Integrating enzymes into thermoplastic polymers is challenging due to their lack of robustness with respect to temperature and shear fields during conventional melt processing. In the present study, blown films from low-density polyethylene (LDPE) were prepared containing a technical protease from Bacillus sp. First, LDPE/protease compounds were produced followed by blown film extrusion, both processes at melt mass temperatures of 130 °C or higher. Enzyme activity was proven, both for the LDPE/protease compound and the blown film. The highest enzyme activity in the compound was determined for processing at 132 °C and a screw speed of 75 rpm. The influence of melt temperature and shear fields was studied in detail. Enzyme activities were determined for melt temperatures up to 160 °C and for screw speeds ranging from 75 to 300 rpm during compounding by twin-screw extrusion. The process was also applied for biobased and biodegradable polyesters, where similar protease activity after compounding was verified. Electron microscopy, X-ray diffraction, nuclear magnetic resonance spectroscopy and differential scanning calorimetry served to analyze components and morphology of the enzyme formulation used here. It is proposed that the porous morphology of the protease particles is beneficial for the enzyme to remain active after processing. Additionally, the polymer matrix surrounding the particles protects the protease at elevated temperatures, which can be attributed to thermal insulation. Thus, the right combination of a suited technical enzyme formulation with appropriate mild melt compounding conditions allows enzymes to be incorporated into thermoplastics and retain their activity. This opens the way to use the abundant biological functions of enzymes in thermoplastic applications.