Grenzen des „digitalen Radiergummis“

Der Beitrag zeigt die prinzipiellen und technischen Untauglichkeiten der Durchsetzung des Konzepts eines „digitalen Radiergummis“ auf, mit dem Inhalte im Internet mit einem Verfallsdatum versehen und somit zeitlich begrenzt zug?nglich gemacht werden sollen.     

Diffractive incremental and absolute coding principle for optical rotary sensors

Rotary sensors are an essential component in numerous applications where a rotation movement has to be detected. With optical encoders, a high angular resolution can be achieved. As a disadvantage, the resolution enhancement is associated with increasing cost. To overcome this issue, a coding principle is presented that uses a diffractive solid measure on a microstructured plastic disc. Like a DVD, this encoder disc can be manufactured in a cost effective injection molding process. For this approach, a differential incremental code, as well as an absolute code, has been developed.     

Towards mass production of microstructured fuel processors for application in future distributed energy generation systems: A review of recent progress at IMM

Fuel cell technology has a crucial role to play in future sustainable and distributed energy generation. With the issue of a reliable hydrogen supply in mind, fuel processing of fossil and renewable fuels is a viable option. Mobile and portable power generation systems require a compact hydrogen source when fuel cell technology is applied especially in applications focused on the small scale stationary level. Fuel processing is a feasible option to meet the limited space demands of auxiliary power units (APUs) due to the high energy density of liquid fuels. Many critical issues need to be addressed when microstructured reactors are applied. The most crucial of these are scale-up with respect to system integration, careful control of heat management and an increase in the durability of the catalyst.     

Development and evaluation of a microreactor for the reforming of diesel fuel in the kW range

The development and evaluation of a reactor based on microchannel technology for the reforming of diesel fuel is reported. The reactor itself was based on an integrated reformer/burner heat exchange reactor concept. 38 h of diesel reforming was performed at temperatures above 750 °C and at various S/C ratios, down to a minimum of 3.17, up to an electrical power equivalent of 5 kW. Over 98% total diesel conversion was observed at all times over the testing period. Variation of experimental parameters such as O/C and S/C ratios are critical for optimum operation of the reformer.     

The development and evaluation of microstructured reactors for the water gas shift and preferential oxidation reactions in the 5 kW range

5 kW_el One-Stage Water Gas Shift (WGS) and Preferential Oxidation (PROx) reactors were designed and evaluated for the clean-up of surrogate diesel reformate. For the WGS reactor, CO conversions of up to 95% were attained using typical surrogate synthetic diesel reformate. The PROx reactor was capable of converting a feed concentration of 1.0 mol% CO to 20 ppm. Load changes for both reactors could be carried out without significant overshoots of carbon monoxide.     

Ausscheidungsverhalten eines warmfesten niobstabilisierten austenitischen Chrom-Nickel-Molybdän-Stahles

Röntgenfeinstrukturuntersuchungen sowie licht- und elektronenmikroskopische Untersuchungen zum Ausscheidungsverhalten eines Stahles ähnlich X 8 CrNiMoNb 16 16. Zeit-Temperatur-Ausscheidung-Schaubild. Überlegungen zur Umwandlungskinetik.     

The Bouma-Janssen method as a tool for the evaluation of macro and micro nutrient status of cotton soils from Nepal

The double pot technique called Bouma-Janssen method, was used to evaluate the nutrient status of three soils of the UNDP Cotton Project, Nepal. In all three soils, N deficiency could be assessed both by soil analysis and pot experiments using a double pot technique. P- and K-deficiency, which were expected from soil analysis, could be confirmed in two of the three soils. The double pot experimental technique proved to be suitable for the rapid evaluation of the macro nutrient status of cotton soils under circumstances where no laboratory facilities are available. More studies are needed in relation to micro nutrients.