Determination of Relaxation Moduli and Poisson‘s Ratio in Uniaxially Loaded Solid Polyethylene Foam Specimens as Part of Full Material Characterization

The mechanical behavior of a solid polyethylene foam is characterizedby a constitutive equation which is of second order in the linearstrain tensor. It turns out that for the determination of the sixtime dependent material functions relaxation tests intension/compression, torsion and, for instance, in isotropic tension andcompression are necessary. For tension/compression tests theexperimental procedure is described in detail. Main emphasis is givento the methods of optical deformation measurement techniques. Resultsfor the relaxation moduli in tension/compression and for the Poissonsratio are presented.     

Carbon nanotubes and mesenchymal stem cells: biocompatibility, proliferation and differentiation

The synergy of the unique properties of carbon nanotubes (CNT) with the remarkable potential of human mesenchymal stem cells (hMSC) provides an exciting opportunity for novel therapeutic modalities. However, little is known about the impact of CNT on hMSC behavior. We report the effect of CNT on hMSC renewal, metabolic activity, and differentiation. Furthermore, we tracked the intracellular movement of CNT through the cytoplasm to a nuclear location and assessed effects on cellular ultra structure.     

Application of infrared ATR spectroscopy to in situ reaction monitoring

The infrared horizontal ATR technique was adapted to be applied for in situ reaction monitoring even at high pressure and high temperature. Different types of reactors and flow cells were built which can be used for recording IR ATR spectra at pressures up to 200 bar and temperatures up to 300°C.

The use of the horizontal ATR technique is shown by the following application examples:

• addition reaction of n-butyl isocyanate with butyric alcohol;

• investigation of the equilibrium of isocyanate, HCl and carbamic acid chloride at elevated pressure and temperature;

• monitoring the polycondensation of bifunctional alcohols and carbonic acids;

• recording spectra of polymer melts at 280°C.

Aus Luftschiffhalle wird Tropischer Regenwald ndash; Brandschutzkonzepte für die größte Halle der Welt

From an airship dockyard to a tropical rainforest ndash; fire protection concept for the the largest hall construction of the world. Tropical Islands is a project with enormous dimensions and very specific utilizations. It is used as a dockyard for large cargo airships as well as for recreational and event presentation purposes with a tropical rainforest in it. This article does not show the complete fire protection concept but has represented certain aspects and focal points that transcend the project and could be of general interest. The results of smoke tests and their specific implementation concerning the particular conditions of the dockyard were shown to point out the very special question of smoke exhaust venting. For the intended new usage of the building the effectiveness of the measures was tested systematically under various conditions and trough successive mathematical approximation. In this case it was pointed out that it was more important to see the superior context than to simulate single scenarios. This cognition may also be useful for projects which are less spectacular. This project is an ideal example to show how largely fire protection measures must and can be adapted to the specific usage of the building. This aspect becomes more important especially in times where buildings were used in other ways as they were intended originally because of economical decisions or simply to conserve resources.     

Das Scaling‐Down‐Problem bei der Zweistoff‐Gaszerstäubung von Metallschmelzen

The production capacities of plants for metal pulverisation are frequently rated according to the minimum throughput of melt flowing from the distributor crucible to pulverisation. Especially in the case of high‐melting point metals and their alloys deficiencies occur in the thermal balance of the crucible in the exit section as a result of gas expansion at the pulverisation gas jets, which act as heat sinks. Minimum throughputs and associated limiting values of the convective heat transfer of the melt are stipulated in order to prevent "freezing" (solidification of the melt) in the crucible. The pertinent situation is illustrated for copper and steel melts and technical possibilities for compensating for heat deficiencies by inductive heating of the distributor exit are presented. In addition, the demand for minimum throughputs can be abandoned, and there result possibilities of scaling‐down and energy conservation as well as improvement of powder discharge.     

Integrierter Umweltschutz und Biotechnologie: Ökobilanz und Wirtschaftlichkeitsrechnung im Innovationsprozess

The main objectives of integrated approaches to environmental protection in industrial processes are cost reduction and a reduction of environmental impact. Environmental protection measures should be integrated into the innovation processes since it is during the development stage that some 80% of the overall costs arise. Substantial potential for such innovation exists in the chemical industry, especially in the field of fine chemicals. The substitution of traditional chemical industrial procedures by biotechnological methods appears particularly promising. For example, the use of enzymes (extremozymes) or fermentative methods has much to offer. Estimation of the benefits of such procedures critically depends on information instruments such as eco‐balances in combination with analysis of economic efficiency. Since such instruments are not consistent in their approach and application, further considerations concerning the amalgamation are required.     

Benzeneselenenyl Reagents in Organic Synthesis

An account of the most commonly used reagents for the introduction of the benzeneselenyl (phenyl seleno) group is given. The review focuses on the various methods of its introduction as auxiliary, modifying or protective entity, and its subsequent removal, thereby often promoting other reactions as cyclizations or double bond formation. Less emphasis is laid on reactions of the phenylselenenylated intermediates with the PhSe-group left intact utilizing its stabilizing properties on charged intermediates, on reagents with a modified phenyl group, e.g. chiral derivatives, or on reactions not involving intermediate C Se-bond formation.     

A new planar chiral bipyridine-ligand: pyrid-2-yl[2](1,4)benzeno[2](5,8)quinolino-phane

The synthesis of the new planar chiral heterocyclic nitrogen ligand pyrid-2-yl[2](1,4)benzeno[2](5,8)quinolino-phane ( 1 with [2.2]paracyclophane-skeleton is described. The enantiomeric resolution is achieved by HPLC. The CD-spectra of 1 and of its chiral quinoline precursor are recorded. The enantiomerically pure title compound 1 is used in copper-catalyzed asymmetric cyclopropanation of styrene and in asymmetric iridium-catalyzed transfer-hydrogenation of acetophenone.