A complete miniaturized microstructured methanol fuel processor/fuel cell system for low power applications

A complete miniaturized methanol fuel processor/fuel cell system was developed and put into operation as compact hydrogen supplier for low power application. The whole system consisting of a micro-structured evaporator, a micro-structured reformer and two stages of preferential oxidation of CO (PROX) reactor, micro-structured catalytic burner, and fuel cell was operated to evaluate the performance of the whole production line from methanol to electricity. The performance of micro methanol steam reformer and PROX reactor was systematically investigated. The effect of reaction temperature, steam to carbon ratio, and contact time on the methanol steam reformer performance is presented in terms of catalytic activity, selectivity, and reformate yield. The performance of PROX reactor fed with the reformate produced by the reformer reactor was evaluated by the variation of reaction temperature and oxygen to CO ratio. The results demonstrate that micro-structured device may be an attractive power source candidate for low power application.     

Anti-Inflammatory Characteristics of Local Anesthetics: Inhibition of TNF-α Secretion of Lipopolysaccharide-Stimulated Leucocytes in Human Blood Samples

Background. Local anesthetics (LAs) have potent anti-inflammatory properties. Inflammatory down-regulation is crucial in diseases with overactive immune reactions, such as acute respiratory distress syndrome (ARDS) and chronic inflammation. We investigated the influence of four LAs, procaine, lidocaine, mepivacaine, and bupivacaine, on the reduction of tumor necrosis factor-alpha (TNF-α) secretion in lipopolysaccharide (LPS)-activated human leucocytes. Methods. Blood samples of 28 individuals were stimulated with LPS. The reduction of TNF-α production by each of the four LAs added (0.5 mg/mL) was measured and correlated with biometric variables. A response was defined as reduction to <85% of initial levels. Results. All four LAs down-regulated the TNF-α secretion in 44–61%: Bupivacaine (44.4%), lidocaine (61.5%), mepivacaine (44.4%), and procaine (50% of the individuals, “responders”). The TNF-α secretion was reduced to 67.4, 68.0, 63.6, and 67.1% of the initial values in responders. The effects in both patients and healthy persons were the same. Interindividual responses to LAs were not correlated with the duration or type of complaints, basal TNF-α serum level, sex, BMI, or age of responders. Conclusions. Four clinically relevant LAs (amid-LA and ester-LA) attenuate the inflammatory response provoked by LPS. They are potential candidates for drug repositioning in treating overactive immune reactions and chronic inflammation.     

Influence of pressure-assisted polymerization on the microstructure and strength of polymer-infiltrated ceramics

A method of manufacturing polymer-infiltrated ceramics (PICs) is to pre-infiltrate a porous ceramic with a liquid monomer and subsequently polymerize the organic component inside the ceramic structure. The volume reduction during polymerization leads to the formation of pores (defects), which has a detrimental effect on the mechanical properties of PICs. To avoid the generation of defects, a new polymerization method that uses pressure during polymerization was developed. To investigate the influences of pressure and heating rate on strength and microstructure, both parameters were varied. The influences of both parameters on the strength of PICs were studied using a biaxial test. The influence on the microstructure was investigated through microscopy. Fracture toughness and R-curve behavior of the manufactured PICs were determined with the SEVNB method. The process parameters have a strong influence on strength and microstructure of PICs. Defect-free PICs with improved strength could be manufactured using elevated pressure during polymerization. As expected, a distinct R-curve behavior and enhanced fracture toughness relative to composites manufactured using conventional methods was found. The developed manufacturing method leads to defectless PICs with increased mechanic behaviors.     

Energieeffizienz in der Vakuumtechnik

Energy efficiency in vacuum technology Vacuum is used to produce a huge variety of products of our everyday life. To provide the vacuum environment, a lot of energy is usually used and therefore the vacuum pumps should run as efficient as possible. Actually, many various improvements can be made to gain energy savings on vacuum pumps. With those considered in this paper it's possible to save 928 GWh/a of energy in the EU and thereof 629 GWh/a or 64 % are economically realizable. Only specific improvements concerning the vacuum system are taken into account, basic technology options, like motors, controls, etc., are excluded. To show and discuss the results a conserved energy supply curve is used.     

The acceptance of Tablet-PCs in classroom instruction: The teachers’ perspectives

Limited research has been conducted on the integration of Tablet-PCs in classroom instruction. This paper reports a qualitative study which investigates the acceptance of Tablet-PCs, seen as technological innovation, amongst teachers. The research approach intends to complement research on the acceptance of technology through a more detailed qualitative examination. Semi-structured interviews were conducted with 18 teachers during a pilot project introducing Tablet-PCs to classroom instruction at three different schools. The findings indicate diversity in the attitude of teachers towards the technology, but also with regards to the performance expectancy and the facilitating conditions.     

Assessment of space division strategies for generation of adequate computational models for solid foams

The present study is concerned with a competitive assessment of different strategies for the division of space in the generation of computational models for the microstructure of solid foams for a numerical analysis of their properties. The study includes the standard (Γ‐) Voronoi procedure, the δ-Voronoi procedure, a Voronoi procedure in Laguerre geometry as well as a simple foam evolution strategy. In addition to the basic versions of the individual strategies, smoothing and optimization approaches are used for a further improvement of the generated computational models. The quality of the models is assessed in terms of two quantitative criteria where the first criterion is the Kelvin parameter whereas the second criterion is based on the error in the statistical cell size distribution compared to experimental observations reported in the literature. All strategies are applied to the simplified case of two-dimensional model foams. Nevertheless, the results can be generalized to the three-dimensional case in a straight forward manner.     

Novel polyamide nanocomposites based on silicate nanotubes of the mineral halloysite

In this study, the silicate nanotubes of the mineral halloysite will be used as reinforcement in polyamide-6 (PA 6). The nanocomposites based on PA-6 and as-received halloysite were prepared by melt extrusion and an adjacent injection moulding process. Mechanical and thermomechanical properties have been investigated by tensile testing and dynamic mechanical analysis. The results show an increased strength and stiffness as well as an enhanced elongation at break at low halloysite content. To evaluate the potential of halloysite as a new candidate in the class of nanofillers, the properties of the halloysite nanocomposites has been compared to those of conventional nanocomposites based on organically modified montmorillonite. From this comparison it can be seen, that both types of nanocomposites show enhanced tensile properties as well as an increased storage modulus, but the increase in tensile strength is more pronounced in the organoclay nanocomposites, whereas the raise of the storage modulus is more prominent in the halloysite nanocomposites.     

The impact of the EU ETS on the sectoral innovation system for power generation technologies – Findings for Germany

This paper provides an overview of early changes in the sectoral innovation system for power generation technologies which have been triggered by the European Emission Trading System (EU ETS). Based on a broad definition of the sector, our research analyses the impact of the EU ETS on the four building blocks ‘knowledge and technologies’, ‘actors and networks’, ‘institutions’, and ‘demand’ by combining two streams of literature, namely systems of innovation and environmental economics. Our analysis for Germany is based on 42 exploratory interviews with experts in the field of the EU ETS, the power sector, and technological innovation. We find that the EU ETS mainly affects the rate and direction of technological change of power generation technologies within the large-scale, coal-based power generation technological regime, to which carbon capture technologies are added as a new technological trajectory. While this impact can be interpreted as the defensive behaviour of incumbents, the observed changes should not be underestimated. We argue that the EU ETS’ impact on corporate CO₂ culture and routines may prepare the ground for the transition to a low-carbon sectoral innovation system for power generation technologies.