Transitional Flow Modeling and Application to High-Lift Multi-Element Airfoil Configurations

To enhance its capabilities to handle flows with transition, a Reynolds averaged Navier-Stokes solver has been extended with regard to the modeling of transitional flow regions based on transition length models and the intermittency function. Because the full coupling of the solver to an e*-method that predicts the locations of transition onset has not yet been completed, the points of laminar separation are supposed to represent the transition locations in a first step. A method and an algorithm for detecting the laminar separation points are derived, and the intermittency function and two transition length models are implemented and validated for a selected high-lift multi-element test case. The background of the implementation work and the testing of the functionalities of the algorithms are focused on. Details of the implementation, which are consequences of an underlying transition prediction strategy, are outlined. the testing is described and then documented

Minimum weight shield synthesis for space vehicles

Minimum weight proton shield synthesis for space vehicle

A surface-fitting program for areally- distributed data from the earth sciences and remote sensing

Fortran II program for analysis of data from earth sciences and remote sensin

Effects of environmental factors on carotenoid content in tomato (Lycopersicon esculentum (L.) Mill.) grown in a greenhouse

Tomatoes are an important source of lycopene in the human diet. The effect of temperature (15°C - 24°C), CO2 supply (380 - 1000 ppm) and nutrient concentration measured as electrical conductivity of the nutrient solution (EC, 2 - 9 dS m-1) on the content of carotenoids (lycopene, ß-carotene) were investigated in two tomato cultivars grown in a greenhouse. The cherry tomato cultivar Supersweet was characterised by higher lycopene contents than the conventional round tomato ‘Counter’. The results indicated that temperature has a significant influence on the biosynthesis of lycopene and ß-carotene during ripening. A temperature above 20°C seems to be optimal for lycopene production in the investigated cultivars, whereas a decrease to 15°C diminished the lycopene content. Neither CO2 supply nor EC increase affected the carotenoid content under the conditions investigated

Changes in quercetin and kaempferol concentrations during broccoli head ontogeny in three broccoli cultivars

Three broccoli cultivars – spear broccoli ‘Emperor’, crown broccoli ‘Marathon’ and violet broccoli ‘Viola’ – were harvested during head ontogeny from start of head development until over maturity stage (five stages) in three different years. The aglycones quercetin and kaempferol were analysed at optimised conditions of acid hydrolysis by HPLC. Heads of over maturity stage had the highest contents of quercetin and kaempferol. However, the genotype fundamentally determined the quantity and course of the increase in flavonols. Mini broccoli, as a new trend to market vegetables, has lower content of flavonols than the commercial stage, which indicates a reduction in health potentials. Harvesting broccoli heads of over maturity stage should be used as raw material, e.g. for the design of new functional foods

Food supplementation among HIV-infected adults in Sub-Saharan Africa: Impact on treatment adherence and weight gain

This is the author's manuscript of an article published in the Proceedings of the Nutrition Society.Sub-Saharan Africa has the highest proportion of undernourished people in the world, along with the highest number of people living with HIV and AIDS. Thus, as a result of high levels of food insecurity many HIV patients are also undernourished. The synergism between HIV and undernutrition leads to poor treatment adherence and high mortality rates. Undernutrition has a debilitating effect on the immune system due to key nutrient deficiencies and the overproduction of reactive species (oxidative stress), which causes rapid HIV progression and the onset of AIDS. Therapeutic food supplementation used in the treatment of severe acute malnutrition is being applied to HIV palliative care; however, little biochemical data exist to highlight its impact on oxidative stress and immune recovery

New methods for unmixing sediment grain size data

Grain size distribution (GSD) data are widely used in Earth sciences and although large data sets are regularly generated, detailed numerical analyses are not routine. Unmixing GSDs into components can help understand sediment provenance and depositional regimes/processes. End-member analysis (EMA), which fits one set of end-members to a given data set, is a powerful way to unmix GSDs into geologically meaningful parts. EMA estimates end-members based on covariability within a data set and can be considered as a nonparametric approach. Available EMA algorithms, however, either produce suboptimal solutions or are time consuming. We introduce unmixing algorithms inspired by hyperspectral image analysis that can be applied to GSD data and which provide an improvement over current techniques. Nonparametric EMA is often unable to identify unimodal grain size subpopulations that correspond to single sediment sources. An alternative approach is single-specimen unmixing (SSU), which unmixes individual GSDs into unimodal parametric distributions (e.g., lognormal). We demonstrate that the inherent nonuniqueness of SSU solutions renders this approach unviable for estimating underlying mixing processes. To overcome this, we develop a new algorithm to perform parametric EMA, whereby an entire data set can be unmixed into unimodal parametric end-members (e.g., Weibull distributions). This makes it easier to identify individual grain size subpopulations in highly mixed data sets. To aid investigators in applying these methods, all of the new algorithms are available in AnalySize, which is GUI software for processing and unmixing grain size data

The shape and erosion of pebbles

The shapes of flat pebbles may be characterized in terms of the statistical distribution of curvatures measured along their contours. We illustrate this new method for clay pebbles eroded in a controlled laboratory apparatus, and also for naturally-occurring rip-up clasts formed and eroded in the Mont St.-Michel bay. We find that the curvature distribution allows finer discrimination than traditional measures of aspect ratios. Furthermore, it connects to the microscopic action of erosion processes that are typically faster at protruding regions of high curvature. We discuss in detail how the curvature may be reliable deduced from digital photographs.Comment: 10 pages, 11 figure

The impact of biological bedforms on near-bed and subsurface flow: a laboratory evaluated numerical study of flow in the vicinity of pits and mounds

The complex surface topography of river substrates controls near-bed hydraulics and drives the exchange of subsurface and surface flow. In rivers, the topographic structures that are studied are usually formed by the flow but, it is known that many animals also create biogenic bedforms, such as pits and mounds. Here, a Large-Eddy Simulation (LES) model of flow over a pit and a mound is evaluated with flume experiments. The model includes actual bedform topography, and the topographic complexity of the surrounding bed surface. Subsurface grains are organized in a body-centered cubic packing arrangement. Model evaluation showed strong agreement between experimental and modelling results for velocity (R2 > 0.8) and good agreement for Reynolds stresses (R2 > 0.7), which is comparable to other similar studies. Simulation of the pit shows that the length of the downwelling region is smaller than the upwelling region and that the velocity magnitude is higher in the downwelling region. Simulation of the mound reveals that the flow is forced into the bed upstream of the mound and re-emerges near the top of the mound. The recirculation zone is limited at the leeside of the mound. With increasing Reynolds number, the depth of the upwelling region at the leeside of the mound increases. The analysis of shear stress indicates that sediments on the upstream edge of the pit and on the downstream face of the mound are relatively unstable. These results demonstrate the effect of biogenic structures on the near-bed flow field, hyporheic exchange, and sediment stability

What is in a pebble shape?

We propose to characterize the shapes of flat pebbles in terms of the statistical distribution of curvatures measured along the pebble contour. This is demonstrated for the erosion of clay pebbles in a controlled laboratory apparatus. Photographs at various stages of erosion are analyzed, and compared with two models. We find that the curvature distribution complements the usual measurement of aspect ratio, and connects naturally to erosion processes that are typically faster at protruding regions of high curvature.Comment: Phys. Rev. Lett. (to appear