Scenario Views for Visual Behavior Models in GenGED

Visualizing and simulating the behavior of formal models in an adequate and flexible way becomes increasingly important in the design of complex systems. With GenGED, a tool is available which automatically generates a visual environment to process (create, edit, check, simulate) visual models in a specified formalism (a visual language). Both the specification of the formalism and the model manipulation are based on graph grammars. In this paper we present the means to transform a formal model into different application domain oriented views (scenario views). We show how the behavior of the model is transferred to the views and animated there (i.e. simulated in the layout of the application domain). Possible extensions towards animation modules (animated scenario views defined by GenGED that are accessible from other tools) are discussed.     

Zur Oxidationsstabilität von Lipiden in den n-Alkanhefen

Oxidation Stability of Lipids in n-Alkane Yeasts Two n-alkane yeasts containing 3.9% and 8.9% lipids are subjected to a storage test over 52 days with 70°C (darkness). At intervals of 7 days the lipids are extracted and their autoxidation state determined by means of the numbers of peroxides and carbonyls. These data suggest certain correlations with the extinction values of the water vapour distillate at 225 nm and 273 nm. The investigations on hand show that the lipid component in the n-alkane yeasts is relatively stable.     

Italian ryegrass silage in winter feeding of organic dairy cows: forage intake, milk yield and composition

BACKGROUND: Organic milk production aims at efficient use of home‐grown feeds, especially forages, to minimise the quantity of purchased feeds. In conventional agriculture, Italian ryegrass (Lolium multiflorum Lam.) is known for its high energy content and palatability, and the aim of the present study was to examine its suitability as feed for organic dairy cows. Therefore a feeding trial was conducted comparing a diet including 50% (of silage dry matter (DM)) of Italian ryegrass silage with a control diet based on grass/clover silage (a mixture of the second cut from permanent grassland and the second cut from a perennial clovergrass ley) alone. RESULTS: Inclusion of Italian ryegrass silage in the diet increased forage intake significantly (14.5 vs 13.4 kg DM in the control group) and concentrate intake did not differ, but milk yield was slightly lower (20.3 vs 21.0 kg) owing to the low energy and protein concentration of Italian ryegrass silage. CONCLUSION: Italian ryegrass was indeed found to be highly palatable, confirming in principle its suitability as feed for organic dairy cows. However, higher energy and protein concentrations in this forage would be necessary to translate the high intakes of Italian ryegrass silage into improved milk production as well. Copyright © 2010 Society of Chemical Industry     

Platinum-plated nanoporous gold: An efficient,low Pt loading electrocatalyst for PEM fuel cells

Platinum-plated nanoporous gold leaf (Pt-NPGL) is made by coating a conformal, atomically thin skin of platinum over the high surface area pores of a thin membrane of nanoporous gold. Because Pt loading in Pt-NPGL can be controlled down to 0.01 mg cm⁻² using only simple benchtop chemistry, the material holds promise as a low Pt loading, carbon-free electrocatalyst. Here, we report successful use of Pt-NPGL as a catalyst in proton exchange membrane (PEM) fuel cells. Stable and high performance Pt-NPGL/Nafion membrane electrode assemblies (MEAs) were made using a stamping technique. The performance of Pt-NPGL MEAs is comparable to conventional carbon-supported nanoparticles-based MEAs with much higher loading, generating an output power density of up to 4.5 kW g⁻¹ Pt in our non-optimized test configuration. Correlations between the performance of Pt-NPGL MEAs, the electrochemically accessible surface area, and material microstructure are discussed. Our success in using Pt-NPGL as a fuel cell catalyst suggests that creating precious metals skins over nanoporous metal supports is a viable strategy for designing new catalysts for PEM fuel cells. This promising approach allows tailoring catalytic activity by engineering precious metal/substrate interactions, employs materials with dual functionality acting both as current collector and catalyst, and may avoid the sintering problems plaguing conventional nanoparticle-based catalysts.     

The magnetic compass mechanisms of birds and rodents are based on different physical principles.

Recently, oscillating magnetic fields in the MHz-range were introduced as a useful diagnostic tool to identify the mechanism underlying magnetoreception. The effect of very weak high-frequency fields on the orientation of migratory birds indicates that the avian magnetic compass is based on a radical pair mechanism. To analyse the nature of the magnetic compass of mammals, we tested rodents, Ansell's mole-rats, using their tendency to build their nests in the southern part of the arena as a criterion whether or not they could orient. In contrast to birds, their orientation was not disrupted when a broad-band field of 0.1-10MHz of 85nT or a 1.315MHz field of 480nT was added to the static geomagnetic field of 46000nT. Even increasing the intensity of the 1.315MHz field (Zeeman frequency in the local geomagnetic field) to 4800nT, more than a tenth of the static field, the mole-rats remained unaffected and continued to build their nests in the south. These results indicate that in contrast to that of birds, their magnetic compass does not involve radical pair processes; it seems to be based on a fundamentally different principle, which probably involves magnetite.     

Biocompatibility of ultra-high molecular weight polyethylene (UHMW-PE) stabilized with α-tocopherol used for joint endoprostheses assessed in vitro

Adding the natural antioxidant α-tocopherol to ultra-high molecular weight polyethylene (UHMW-PE) can remarkably delay the oxidation of hip cups made thereof. However, α-tocopherol is likely to undergo different chemical transformations during manufacturing and sterilization of hip cups than in human metabolism. Therefore, the biocompatibility of the putative transformation products has to be investigated. In-vitro tests with L929 mice fibroblast-cells gave no evidence for cytotoxicity. To further ensure the biocompatibility, in-vitro tests with human cells were carried out in this study. Two different human cell lines, one adherent cell line, HF-SAR, and one suspension culture, GSJO, were tested on UHMW-PE-tablets (diameter: 15 mm; thickness: 2 mm; processed according to standard procedures for artificial hip-cups) with and without α-tocopherol with respect to cell viability, proliferation and morphology by means of cell counting, WSt-1 proliferation assay and scanning electron microscopy. Similar proliferation rates were found with both polyethylene samples. Further, we found intact morphology in light and electron microscopy on each substrate. The morphologic characteristics of skin fibroblasts were not changed by any material. Normal adherence and spreading of the fibroblasts was found on controls of glass, as well as on polystyrene and on stabilized and unstabilized polyethylene. The characteristic behaviour as suspension of the GSJO cells remained unchanged. The mitochondrial activity, as studied by WST-1 cell proliferation reagent, was identical on each substrate during the whole observation period of 7 days. Christian Wolf—in partial fulfillment of a Ph.D. (Dr.mont.) thesis at the University of Leoben     

Index Criteria for Differential Algebraic Equations Arising from Linear-Quadratic Optimal Control Problems

The index of DAE systems arising from linear quadratic optimal control problems is considered. Necessary and sufficient conditions ensuring regularity with tractability index one are proved. Then, it is shown that if the control problem DAE is regular with index one and if the leading term of the DAE to be controlled is given by one full-column-rank and one full-row-rank matrix, then it has a Hamiltonian inherent explicit ODE. For problems with regular index zero or index one DAEs to be controlled, the DAE of the control problem is shown to be regular with tractability index one or three, depending on whether the control coefficient R is singular. 2000 Mathematics Subject Classification. 49N10, 49J15, 34A09. Supported by the DFG research center MATHEON in Berlin. This work was partially supported by the Russian Fundamental Research Foundation Project Nos. 02-01-00351 and 06-01-00296.     

Effects of compression on water distribution in gas diffusion layer materials of PEMFC in a point injection device by means of synchrotron X-ray imaging

In this study, ex-situ experiments performed with a point injection device are conducted to evaluate water distributions in gas diffusion layer (GDL) materials which serve as porous transport media in polymer electrolyte membrane fuel cells (PEMFCs). In this regard, GDL samples manufactured by SGL Group are placed into the point injection device and visualized by means of synchrotron X-ray radiographic and tomographic imaging. The resulting image data undergoes a coordinate transformation that ascertains water agglomerations in GDL pores with regard to their radial displacements from the injection point. In this way, water transport in two different GDL samples possessing the same structural characteristics, but with unique compression rates, are investigated in terms of in-plane water distribution. The radial displacement analysis indicated that the pore saturation of the compressed GDL is higher in both the micro porous layer (MPL) region and the carbon fiber substrate region than that of the uncompressed GDL. The water agglomerations in the uncompressed GDL are predominantly observed in the vicinity of the injection point, indicating a limited in-plane transport. Conversely, in the compressed case water accumulations are detected far from the injection point, even at the edge of the GDL, pointing out that compression promotes the in-plane transport. Prior to the ex-situ experiments, both GDL samples have undergone an ageing procedure to mimic realistic cell operating conditions.     

Phytochemical composition and antioxidant capacity of various botanical parts of the fruits of Prunus × domestica L. from the Lorraine region of Europe

Mirabelle plums represent a famous fruit from the Lorraine region, however little is known about their phytochemical composition. The oil of the fruit contained predominantly oleic acid (59%) and linoleic acid (29%). The total content of phenolic antioxidants in the whole fruits was 5.338 g/kg with 456 mg/kg (9%), 701 mg/kg (13%) and 4159 mg/kg (78%) detected in the peels, flesh and pits respectively. The peels contained solely 3,4-dihydroxybenzoic acid (270 mg/kg) and rutin (186 mg/kg), the flesh exclusively echinoids (723 mg/kg), whereas the pits contained a rich variety of phenolic compounds (4.2 g/kg) dominated by amygdalin (3.8 g/kg), but with significant contributions from vanillin (102 mg/kg), guajacyl-glycerin-coniferyl aldehyde isomers (87 mg/kg), dehydro-diconiferyl aldehyde (52 mg/kg), and vanillin diglucoside (48 mg/kg). Of the major phenolic compounds tested across a range of in vitro assays, rutin was the superior antioxidant.