Definition of a system to extract hot gas from an entrained flow gasifier

This project work covers the design and construction of a new probe system for hot gas analysis in an entrained flow gasifier. The aim is a probe that can be used more flexibly than the present system. As a further aim, the condensation of trace materials has to be prevented. First, a short overview over current techniques to analyse the product gas in a gasification process is given. Continuing, the report describes the finding and assessing of several possible principles of hot gas extraction from a gasification process using simulations in ANSYS Fluent. The best performing design based on defined trace component condensation is built for a verification experiment and tested under controlled conditions in a tube furnace. Verification experiments comprise temperature measurements and analysis of retrieved samples via x-ray induced fluorescence. Temperature measurements show that the planned effect of mixture cooling is exceeded by far by convective cooling of the probe. Although simulations were promising, the approach is not applicable under current operating conditions due to problems with the measurement system. Furthermore, the amount of condensed trace material in the retrieved samples proves not to be sufficient for quantitative analysis via x-ray fluorescence. An alternative system to retrieve hot gas while maintaining it at high temperatures out of the gasifier is then modeled

Thermophoresis and its effect on particle impaction on a cylinder for low and moderate Reynolds numbers

The effect of thermophoresis on the impaction of particles on a cylinder is investigated for different particle sizes, particle conductivities, temperature gradients and for Reynolds numbers between 100 and 1600. Simulations are performed using the Pencil Code, a high-order finite difference code. An overset-grid method is used to precisely simulate the flow around the cylinder. The ratio of particles impacting the cylinder and the number of particles inserted upstream of the cylinder is used to calculate an impaction efficiency. It is found that both the particle conductivity and the temperature gradient have a close to linear influence on the particle impaction efficiency for small particles. Higher Reynolds numbers result in higher impaction efficiency for middle-sized particles, while the impaction efficiency is smaller for smaller particles. In general, it is found that thermophoresis only has an effect on the small particles, while for larger particles the impaction efficiency is controlled by inertial impaction. Finally, an algebraic model, developed based on fundamental principles, which describes the effect of thermophoresis is presented. The model is found to accurately predict the DNS results. As such, this model can be used to understand the mechanisms behind particle deposition due to the thermophoretic force, and, more importantly, to identify means by which the deposition rate can be reduced

Molecular detection of Setaria tundra (Nematoda: Filarioidea) and an unidentified filarial species in mosquitoes in Germany

<p>Abstract</p> <p>Background</p> <p>Knowledge of the potential vector role of Culicidae mosquitoes in Germany is very scanty, and until recently it was generally assumed that they are not involved in the transmission of anthroponotic or zoonotic pathogens in this country. However, anticipated changes in the course of global warming and globalization may alter their status.</p> <p>Methods</p> <p>We conducted a molecular mass screening of mosquitoes for filarial parasites using mitochondrial 12S rRNA-based real-time PCR.</p> <p>Results</p> <p>No parasites causing disease in humans such as <it>Dirofilaria </it>spp. were detected in about 83,000 mosquitoes tested, which had been collected in 2009 and 2010 in 16 locations throughout Germany. However, minimum infection rates of up to 24 per 1000 mosquitoes were revealed, which could be attributed to mosquito infection with <it>Setaria tundra </it>and a yet unidentified second parasite. <it>Setaria tundra </it>was found to be widespread in southern Germany in various mosquito species, except <it>Culex </it>spp. In contrast, the unidentified filarial species was exclusively found in <it>Culex </it>spp. in northern Baden-Württemberg, and is likely to be a bird parasite.</p> <p>Conclusions</p> <p>Although dirofilariasis appears to be emerging and spreading in Europe, the absence of <it>Dirofilaria </it>spp. or other zoonotic filariae in our sample allows the conclusion that the risk of autochthonous infection in Germany is still very low. Potential vectors of <it>S. tundra </it>in Germany are <it>Ochlerotatus sticticus</it>, <it>Oc. cantans</it>, <it>Aedes vexans </it>and <it>Anopheles claviger</it>. Technically, the synergism between entomologists, virologists and parasitologists, combined with state-of-the-art methods allows a very efficient near-real-time monitoring of a wide spectrum of both human and veterinary pathogens, including new distribution records of parasite species and the incrimination of their potential vectors.</p

ATHLETIC: Pseudo Anthropometric Exoskeleton with a Semi Passive Actuation System for Countermeasure

This paper presents the ongoing ESA project ATHLETIC (AstronauT HeaLtH EnhancemenT Integrated Countermeasure) which aims to develop a new approach of integrated countermeasure device in the shape of an exoskeleton. It focuses primarily on the training of the lower limbs, which are the most heavily affected body parts while astronauts are exposed to microgravity. The ATHLETIC system enables High Intense Resistive Training exercises (HIRT), as well as plyometric exercises such as hopping and jumping. Development and validation shall give an answer to the question if exoskeleton technology is suitable for countermeasure in zero gravity and how such a system performs compared to existing countermeasure devices for zero gravity applications

Modeling flexibility in energy systems : comparison of power sector models based on simplified test cases

Model-based scenario analyses of future energy systems often come to deviating results and conclusions when different models are used. This may be caused by heterogeneous input data and by inherent differences in model formulations. The representation of technologies for the conversion, storage, use, and transport of energy is usually stylized in comprehensive system models in order to limit the size of the mathematical problem, and may substantially differ between models. This paper presents a systematic comparison of nine power sector models with sector coupling. We analyze the impact of differences in the representation of technologies, optimization approaches, and further model features on model outcomes. The comparison uses fully harmonized input data and highly simplified system configurations to isolate and quantify model-specific effects. We identify structural differences in terms of the optimization approach between the models. Furthermore, we find substantial differences in technology modeling primarily for battery electric vehicles, reservoir hydro power, power transmission, and demand response. These depend largely on the specific focus of the models. In model analyses where these technologies are a relevant factor, it is therefore important to be aware of potential effects of the chosen modeling approach. For the detailed analysis of the effect of individual differences in technology modeling and model features, the chosen approach of highly simplified test cases is suitable, as it allows to isolate the effects of model-specific differences on results. However, it strongly limits the model's degrees of freedom, which reduces its suitability for the evaluation of fundamentally different modeling approaches