Selective Alignment of Molecular Glass Wrinkles by Engineered Magnetic Field Landscapes

A new approach for aligning wrinkles in thin viscoelastic polymethylmethacrylate films is established by sandwiching them between ferromagnetic layers. Experiments prove that a contribution from an engineered anisotropic 1D periodic magnetic stray field pattern can be decisive for the alignment of otherwise randomly oriented wrinkles at commensurate periods of the magnetic template pattern and the wrinkles. Alternatively, random wrinkling is observed under similar conditions, but when periodic magnetic stray fields are missing or not commensurate with the wrinkle wavelength. The possibility to stabilize two distinct types of wrinkling patterns in the same material system paves the way toward mechanically reconfigurable functional elements, enabling exciting possibilities for stretchable electronics, magnetic field sensors, and tuneable gratings for optoelectronics and photonics.     

Kombinierte Herkunftsbestimmung der Wässer im Jökulsáá Fjöllum-Canyon (NE-Island)

The northeastern region of Iceland is characterized by dreary stony deserts and marshland with the exception of the areas Hólmatungur and Forvö in the Jökulsáá Fjöllum-canyon. The rich vegetation and the high density of springs are exceptional in this region. Since many fissure swarms run through the catchment of the Jökulsáá Fjöllum and inside the canyon there are springs with discharges over 300 l/s, it was necessary to investigate the origin of the water in both spring areas. In a field campaign the physicochemical parameters from over hundred springs were measured, samples were taken and analyzed for their water contents and isotopical parameters. Through the combination of interpolated species distibutions with measured fissures and joints and the usage of the index-species sulphate and total-boron to detect geothermal influences and chloride and δ ¹⁸ O, which shows a dependence on the continental effect, it was possible to separate springs with geothermal influences from water of uninfluenced catchments.     

Performance of TES X-ray Microcalorimeters with AC Bias Read-Out at MHz Frequencies

At SRON we are developing Frequency Domain Multiplexing for the read-out of superconducting transition edge sensor microcalorimeters for future X-ray astrophysical missions. We will report on the performance of Goddard Space Flight Center pixels under AC bias in the MHz frequency range. Superconducting flux transformers are used to improve the impedance matching between the low ohmic TESs and the SQUID. We connected 5 pixels to the LC filters with resonant frequencies ranging between 1 and 5 MHz. For X-ray photons of 6 keV we measured a best X-ray energy resolution of 3.6 eV at 1.4 MHz, consistent with the integrated Noise Equivalent Power. In addition, we improved the electrical circuit by optimizing the coupling ratio of the impedance matching transformer. In addition, we improved electrical circuit for impedance matching; modified transformer coupling ratio. As a result, we got the integrated noise equivalent power resolution of 2.7 eV at 2.5 MHz. A characterization of the detector response as a function of the AC bias voltage, bias frequency and the applied magnetic field is presented.     

Effect of dietary vitamin E supplementation on the shelf life of cured pork sausage

This study examined the shelf life of cured sausage under different packaging conditions from vitamin E supplemented pigs. One group (n=6) of crossbred pigs received a normal fattening diet containing 20 ppm α-tocopherol for 39 days before slaughter. Another group was fed a diet containing 410 ppm α-tocopherol during the same period. After slaughter, cured sausages were produced, packaged under three different atmospheric conditions, ripened for 4 weeks and then stored for 8 weeks (9?°C; 200 lux). The α-tocopherol content was recorded in the fat, liver, muscles and the sausage. TBARS, L*, a*, b* values and antioxidative capacity were evaluated in the sausage during storage. The results showed a transfer of vitamin E into tissues and sausage but no detectable effect on TBARS and colour stability. However, antioxidative effects of vitamin E were seen by provocation. Probably the effect of vitamin E in the sausage was masked by nitrite in the curing salt. The oxygen content of the packs had an influence on TBARS and colour stability.     

Combining convergence and diversity in evolutionary multiobjective optimization

Over the past few years, the research on evolutionary algorithms has demonstrated their niche in solving multiobjective optimization problems, where the goal is to find a number of Pareto-optimal solutions in a single simulation run. Many studies have depicted different ways evolutionary algorithms can progress towards the Pareto-optimal set with a widely spread distribution of solutions. However, none of the multiobjective evolutionary algorithms (MOEAs) has a proof of convergence to the true Pareto-optimal solutions with a wide diversity among the solutions. In this paper, we discuss why a number of earlier MOEAs do not have such properties. Based on the concept of epsilon-dominance, new archiving strategies are proposed that overcome this fundamental problem and provably lead to MOEAs that have both the desired convergence and distribution properties. A number of modifications to the baseline algorithm are also suggested. The concept of epsilon-dominance introduced in this paper is practical and should make the proposed algorithms useful to researchers and practitioners alike.     

Performance comparisons of synthetic and mineral oil crankcase lubricant base stocks

The physical and performance characteristics of representative synthetic base stocks are compared with those of mineral oils. Comparisons of the base stocks alone and as fully formulated crankcase lubricants are presented. Bench test results and physical properties of unformulated synthetic and mineral oil base stocks are compared. The volatility characteristics of synthetic base stocks are superior to typical mineral oil base stocks. All the synthetic base stocks displayed greater viscosity indices than did mineral oils. Bench tests designed to measure thermal and oxidative stabilities are used to compare synthetic with mineral oil base stocks. Although synthetics appeared no more resistant to oxidation than did mineral oils, fewer sediments, deposits and fluid viscosity increases were observed with synthetic base stocks. No one type of synthetic base oil showed a distinct advantage in these evaluations. Fully formulated mineral oil-based lubricants are compared with commonly used synthetic-based lubricants containing identical additive treatments. The synthetic lubricants showed superior engine cleanliness, and resistance to viscosity increased in these tests, but were directionally less effective in wear prevention than mineral oil-based lubricants. Proper formulation or addition of an antiwear supplement overcame this deficiency. These comparisons demonstrated that synthetic base stocks are available with a wide range of physical properties. Available synthetic base stocks offer performance advantages at an increased cost over mineral oils, but proper formulation of the synthetic lubricant is necessary to ensure totally acceptable lubricant performance.