Low-pressure microwave plasma sterilization of polyethylene terephthalate bottles

A low-pressure microwave plasma reactor was developed for sterilization of polyethylene terephthalate (PET) bottles. In contrast to the established method using aseptic filling machines based on toxic sterilants, here a microwave plasma is ignited inside a bottle by using a gas mixture of nitrogen, oxygen, and hydrogen. To that effect, a reactor setup was developed based on a Plasmaline antenna allowing for plasma ignition inside three-dimensional packages. A treatment time below 5 s is provided for a reduction of 10(5) and 10(4) CFU of Bacillus atrophaeus and Aspergillus niger, respectively, verified by means of a count reduction test. The sterilization results obtained by means of this challenge test are in accordance with requirements for aseptic packaging machines as defined by the U.S. Food and Drug Administration and the German Engineering Federation. The plasma sterilization process developed here for aseptic filling of beverages is a dry process that avoids residues and the use of maximum allowable concentrations of established sterilants, e.g., hydrogen peroxide.     

New aspects for high-intensity neutron beam production

Neutron scattering is an important tool for the investigation of static and dynamic structures of matter. As it is an intensity limited technique, many attempts have been made to increase the effective beam intensity. High neutron intensities or, more precisely, high phase space densities of neutrons can be obtained at low energies only. Such ultra-cold neutrons can be trapped inside material and magnetic bottles. When neutrons of such densities become up-scattered, highly intense, monochromatic and pulsed beams can be produced, whose intensities can overcome limitations imposed by the classical neutron source strength. We report a recent experiment that demonstrated this alternative, to our knowledge, for the first time ever. Perspectives resulting from this development of highly intense neutron beam production will be discussed. A stationary ultra-cold neutron gas produced becomes transformed into a pulsed and monochromatic cold neutron beam.     

Innovative Raumakustik im Spannungsfeld zwischen Forschung und Markt

Innovative room acoustic between research and market. Adequate room acoustic treatment has become an absolute necessity for the performance and health of users in musicians workspaces and rooms with high communication demands. It is, by no means, a superfluous luxury. Innovative acoustic construction elements as well as research and development concepts must offer additional value besides their acoustic function. Their successful marketing is made possible only by a close cooperation with competent industrial partners. A straightforward cost estimate proves that these investments often cause only little extra expenses, even if the performance and motivation promoting aspects were ignored. During the construction of anechoic rooms, slim anechoic linings e.g. save costs for the building shell in the magnitude of their own price.     

Influence of energetic materials on the energy-output of gun propellants

For the formulation and preparation of gun propellants containing high energetic compounds, methods have been described how to improve the performance. In addition thermodynamic data such as flame temperature, mole number, mean molecular weight, heat of explosion and specific energy were discussed, which are of main influence for the energy-output of energetic materials. In connection with the improvement of performance, a list of components was established, which could be used to increase the energy without increasing the sensitivity of the propellants. At first, the aim was to replace conventional plasticizers by several energetic plasticizers. Taking into account different propellant formulations, the thermodynamic parameters have been calculated which are of interest for improvement of the specific energy. On the other hand, nitramine propellants manufactured at our Institute using different binder systems such as polybutadiene (PB), glycidylazide polymer (GAP) and cellulose acetate butyrate (CAB) have been investigated in a closed bomb in order to evaluate the energy-output and in addition the reaction products by gas analysis. The performance of these LOVA-propellants was discussed in connection with heat of formation, oxygen balance and the kind of polymeric binder system. Finally, energetic compounds such as NTO, CL-20, TNAZ, ANTA and ammonium dinitramide (ADN) have been calculated using the ICT-Thermodynamic Code, in order to assess the energy-output and to be able to discuss a possible improvement of the performance.     

Verarbeitung von Kartoffelstärke auf Kunststoff-Verarbeitungsmaschinen

Processing of Potato Starch on Plastics Processing Machines. Starch as an organic material with macromolecular structure has many properties comparable to usual plastic materials. Therefore, it is possible to manufacture starch products with polymer processing machines by the same methods as synthetic polymers. In addition of special plasticizer native potato starch has been processed to granules and films with different extruders. The granules were taken as feed material for experiments of the production of samples with an injection moulding machine. The mechanical properties of the produced specimens proved to be on a satisfactory level. By the suitability of the widely distributed screw machines for starch processing it is possible to substitute synthetic polymers by starch for special applications without high inital costs. Detailed knowledge about the suitable processing methods is an important condition for that.