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Steinau an der Strasse, Germany

Maass S.,TU Berlin | Wollny S.,Anhalt University of Applied Sciences | Voigt A.,Otto Von Guericke University of Magdeburg | Kraume M.,TU Berlin
Experiments in Fluids | Year: 2011

An online measurement technique for drop size distribution in stirred tank reactors is needed but has not yet been developed. Different approaches and different techniques have been published as the new standard during the last decade. Three of them (focus beam reflectance measurement, two-dimensional optical reflectance measurement techniques and a fiber optical FBR sensor) are tested, and their results are compared with trustful image analysis results from an in situ microscope. The measurement of drop sizes in liquid/liquid distribution is a major challenge for all tested measurement probes, and none provides exact results for the tested system of pure toluene/water compared to an endoscope. Not only the size analysis but also the change of the size over time gives unreasonable results. The influence of the power input on the drop size distribution was the only reasonable observation in this study. The FBR sensor was not applicable at all to the used system. While all three probes are based on laser back scattering, the general question of the usability of this principle for measuring evolving drop size distributions in liquid/liquid system is asked. The exterior smooth surface of droplets in such systems is leading to strong errors in the measurement of the size of the drops. That leads to widely divergent results. A different measurement principle should be used for online measurements of drop size distributions than laser back scattering. © 2010 Springer-Verlag. Source

Michelis D.,Anhalt University of Applied Sciences | Muller J.,Deutsche Telekom AG
International Journal of Human-Computer Interaction | Year: 2011

Data are presented from observations of Magical Mirrors, a set of four large public displays with gesture-based interaction installed in downtown Berlin, Germany. The displays show a mirror image of the environment in front of them and react with optical effects to the gestures of the audience. Observations of audience behavior revealed recurring behavioral patterns, like glancing at a first display while passing it, moving the arms to cause some effects, then directly approaching one of the following displays and positioning oneself in the center of the display. This was often followed by positioning oneself in the center of the other displays to explore the possibilities of the different effects, and sometimes by taking photographs or videos. From these observations a framework of interaction with gesture-based public display systems was deduced. It describes the phases of passing by a display, viewing & reacting, subtle interaction, direct interaction, multiple interactions, and follow-up actions. Quantitative data of these behavioral phases was collected by observing 660 passers-by on 2 weekend evenings. This article shows how many passers-by pass the thresholds between these phases. This "Audience Funnel" should provide a framework to encourage systematic investigation of public display systems and enable comparability between different studies. © Taylor & Francis Group, LLC. Source

Sander M.,Fraunhofer Center for Silicon Photovoltaics | Dietrich S.,Fraunhofer Center for Silicon Photovoltaics | Pander M.,Fraunhofer Center for Silicon Photovoltaics | Ebert M.,Fraunhofer Center for Silicon Photovoltaics | And 2 more authors.
Solar Energy Materials and Solar Cells | Year: 2013

Mechanical and thermal loads on photovoltaic modules (PV modules) lead to mechanical stresses in the module parts and especially in the encapsulated solar cells which can break under a certain load. To investigate the development of cracks in encapsulated solar cells, a novel approach was developed that systematically analyzes the influence of the load direction on the crack directions. For this purpose an experiment is established that tests specimens on smaller scales under well-known boundary conditions. The cell cracks are statistically evaluated and the fracture stress can be compared directly for different crack orientations or different cell types. The test setup is expected to be suitable to systematically investigate the behavior of new cell or module designs or to act as a quality assurance test. For the investigated cells a loading parallel to the busbars causes cracks at lower load magnitudes than a loading perpendicular to the busbars and different cell types show different fracture strength values. The findings can be transferred to full scale modules by calculating a probability of failure for each solar cell. This allows an interpretation of many effects that were observed in full scale PV modules and allows design optimization for reduced cell breakage rates. © 2012 Elsevier B.V. Source

Hildebrandt C.,Anhalt University of Applied Sciences
Journal of integrative bioinformatics | Year: 2011

Mass spectrometry is an important analytical technology for the identification of metabolites and small compounds by their exact mass. But dozens or hundreds of different compounds may have a similar mass or even the same molecule formula. Further elucidation requires tandem mass spectrometry, which provides the masses of compound fragments, but in silico fragmentation programs require substantial computational resources if applied to large numbers of candidate structures. We present and evaluate an approach to obtain candidates from a relational database which contains 28 million compounds from PubChem. A training phase associates tandem-MS peaks with corresponding fragment structures. For the candidate search, the peaks in a query spectrum are translated to fragment structures, and the candidates are retrieved and sorted by the number of matching fragment structures. In the cross validation the evaluation of the relative ranking positions (RRP) using different sizes of training sets confirms that a larger coverage of training data improves the average RRP from 0.65 to 0.72. Our approach allows downstream algorithms to process candidates in order of importance. Source

Hohl M.,Anhalt University of Applied Sciences
Kybernetes | Year: 2015

Purpose – The purpose of this paper is to learn from successful educational frameworks how to inform a possible framework for design education that includes ecological literacy, systems thinking leading to more sustainable and ecological designs. Design/methodology/approach – The author comparing two models for education, the first being that of the Polynesian Voyaging Society which re-emerged as a cultural and educational framework in Hawaii. Second that of the Center for Ecological Literacy in connection with the edible schoolyard. Both frameworks involve systems thinking. Findings – Certain elements that may inform design education. Among these are attention and vision, values, care for nature, culture, community and learning based on systems thinking, exploration and perception of the environment. Language, traditions and a strong local grounding also play a role in the Hawaiian framework. Research limitations/implications – The sources are from personal observations in design education and documentation material provided by educators. The groups with which these principles were enacted are children, whereas my goal is to inform a framework for higher education. Practical implications – The shared characteristics used in the two frameworks might be used to inform curricula for design education from both theoretical perspectives and practical applications. Originality/value – Polynesian voyaging and ecological literacy have both been very successful as educational frameworks since their implementation. Designing is necessary and design education can possibly learn much from these two examples to adapt to future changes. Ecological literacy, an educational perspective, incorporates ideas around sustainability, networks, nested systems, circularity and flows, and using this knowledge to create “sustainable human communities.” Traditionally this is not part of design education. © 2015, Emerald Group Publishing Limited. Source

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