Technische Universität Berlin

8236 Items

Recent Submissions
CFD-basierte evolutions­strategische Black-Box-Optimierung zur Abschätzung des Potentials des Bionikpropellers im realen Einsatz am Schiff

Schmid, Michael (2019)

Die Evolution hat in der Natur viele Lösungen unter dem besonderen Gesichtspunkt der Energieeffizienz hervorgebracht. Dabei sind insbesondere bei Vögeln interessante Lösungen entstanden, die sich im Sinne der Bionik als effizienzsteigernde Maßnamen verstehen und technisch umsetzen lassen. Der bei der Auftriebserzeugung am Vogel- bzw. Tragflügel entstehende Spitzenwirbel ist unvermeidlich, der E...

Features and machine learning systems for structured and sequential data

Schwenk, Guido (2019)

Modern web and communication technology relies heavily on sequential and structured data for its process execution and communication protocols. Due to its complex properties, a manual analysis and detection of problems on this data is too time-consuming and expensive, and hence not feasible. As a consequence, features and automatic learning systems on this type of data are highly sought after. ...

State Representation Learning with Robotic Priors for Partially Observable Environments Data

Morik, Marco ; Rastogi, Divyam ; Brock, Oliver (2019)

We introduce Recurrent State Representation Learning (RSRL) to tackle the problem of state representation learning in robotics for partially observable environments. To learn low dimensional state representations, we combine a Long Short Term Memory network with robotic priors. RSRL introduces new priors with landmarks and combines them with existing robotics priors in literature to train the r...

Fully coupled robust shallow water flow and sediment transport model on unstructured grids

Zhao, Jiaheng (2019)

This Ph.D. thesis advances the fully coupling of robust shallow water flow and sediment transport modeling. The first part mainly focuses on the multislope MUSCL reconstruction for shallow water flow on unstructured grids. A limitation method for reconstruction of velocities avoids extremely high values for wet/dry fronts. The reconstruction methods are tested via analytical benchmarks and lab...

Methodische Entwicklung einer modularen Lasersintermaschine zur Herstellung von bioresorbierbaren Implantatmatrizen

Kautz, Clemens Kolja (2019)

Eine aus dem Bereich der regenerativen Medizin stammende visionäre Anwendung der AM-Technologie ist die Fertigung von individuell angepassten Implantaten und Organen. Werden zur Herstellung von Implantatmatrizen, dem Gerüst zum Gewebeaufbau, bioresorbierbare Werkstoffe mittels Lasersintern verarbeitet, verbleibt das erzeugte Implantat nach der Transplantation im Körper des Patienten und wird do...

Verbesserung des CVB3-Maus-Myokarditismodells durch die Entwicklung pankreasattenuierter Coxsackieviren

Pryshliak, Markian (2019)

Das Coxsackievirus B3 (CVB3)-Maus-Myokarditismodell wird standardmäßig zur Untersuchung der Virus-induzierten Myokarditis verwendet. Entgegen der CVB3-Infektion im Menschen stellt im murinen Organismus nicht das Herz, sondern das Pankreas das für die CVB3-Infektion suszeptibelste Organ dar. Verschiedene klinische Symptome, wie der starke Gewichtsverlust, das schmerzhafte Hochziehen des Bauches ...

Adhesive Strength of Contacts of Rough Spheres

Li, Qiang ; Pohrt, Roman ; Popov, Valentin L. (2019-03-26)

The adhesive contact between a parabolic indenter with superimposed roughness and an elastic half space is studied in the JKR-limit (infinitely small range of action of adhesive forces) using the boundary element method with mesh-dependent detachment criterion suggested in 2015. Three types of superimposed roughness are considered: one- and two-dimensional waviness and randomly rough roughness....

Untersuchungen zur Biosynthese von Omphalotin

Ramm, Sascha (2019)

Originally discovered in 1987, Omphalotin is an undodecapeptide (which is) synthesized by the basidiomycete Omphalotus olearius. The fungal secondary metabolite shows a strong nematicide and selective activity against the plant parasite Meloidogyne incognita. Structurally, it bears various remarkable characteristics, as for example nine methylations of the α-nitrogen atoms in the peptide backbo...

Comparative Study of the Use of Insect Meal from Spodoptera littoralis and Bactrocera zonata for Feeding Japanese Quail Chicks

Sayed, Waheed A.A. ; Ibrahim, Nashaat S. ; Hatab, Mahmoud H. ; Zhu, Fen ; Rumpold, Birgit A. (2019-03-31)

A transformation of current livestock production towards a more sustainable operation is crucial to face nutritional and environmental challenges. There is an urgent demand for more sustainable high-quality feed sources to reduce environmental costs. Insects pose a potential alternative since they can be reared sustainably on food and feed residues. Know-how in mass rearing already exists for i...

A Response to the United Nations CITES Blockchain Challenge: Incremental and Integrative PoA-based Permit Exchange

Busse, Anselm ; Eberhardt, Jacob ; Frost, Sebastian ; Kim, Dong-Ha ; Weilbier, Thore ; Renner, Lukas ; Roth, Matthias ; Tai, Stefan (2019)

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) negotiated and administered by the United Nations Environment Programme (UNEP) regulates the international trade of endangered species and derived products through a permit-based system. Currently, the permit process is paper-based and hence highly prone to manipulations and errors. Being aware of blockc...

Effective and needed, but not used: Why do mobile phone-based health interventions in Africa not move beyond the project status?

Stephani, Victor (2019)

Reviews have shown that mobile phone-based health interventions (mHealth interventions) are capable of improving health outcomes of patients in Africa, particularly for patients with chronic diseases such as non-communicable diseases (NCDs). But currently, most mHealth interventions are stopped after the pilot and the funding of the donors has ceased. The aim is to identify the reasons for the ...

Effect of Different Drying Methods on Nutrient Quality of the Yellow Mealworm (Tenebrio molitor L.)

Kröncke, Nina ; Grebenteuch, Sandra ; Keil, Claudia ; Demtröder, Sebastian ; Kroh, Lothar ; Thünemann, Andreas F. ; Benning, Rainer ; Haase, Hajo (2019-03-27)

Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven dry...

Composition dependent transport diffusion in non-ideal mixtures from spatially resolved nuclear magnetic resonance spectroscopy

Pantoja, Christian F. ; Muñoz-Muñoz, Y. Mauricio ; Guastar, Lorraine ; Vrabec, Jadran ; Wist, Julien (2018-10-16)

Nuclear magnetic resonance (NMR) spectroscopy is a well-established technique for the measurement of intra-diffusion coefficients. Recently, such information has been used as a basis of predictive models to extrapolate to the Fick diffusion coefficient of liquid mixtures. The present work presents a new approach to directly access the Fick diffusion coefficient by spatially resolved NMR experim...

Diffusion Coefficients of a Highly Nonideal Ternary Liquid Mixture: Cyclohexane–Toluene–Methanol

Janzen, Tatjana ; Vrabec, Jadran (2018-10-26)

To better understand diffusion phenomena in highly nonideal ternary liquid mixtures, cyclohexane–toluene–methanol is studied by equilibrium molecular dynamics (EMD) simulation. Intradiffusion and Maxwell–Stefan (MS) diffusion coefficients, being strictly kinetic properties, are predicted by EMD over the entire composition range at ambient conditions. The thermodynamic contribution to the Fick d...

Kirkwood-Buff integration: A promising route to entropic properties?

Fingerhut, Robin ; Vrabec, Jadran (2018-12-13)

Kirkwood-Buff integration (KBI) is implemented into the massively-parallel molecular simulation tool ms2 and assessed by molecular dynamics simulations of binary liquid mixtures. The formalism of Krüger et al. (P. Krüger et al., J. Phys. Chem. Lett. 4: 235–238, 2013) that adopts NVT ensemble data to the μVT ensemble is employed throughout. Taking advantage of its linear scaling with inverse sys...

Diffusion limited evaporation of a binary liquid film

Chatwell, René Spencer ; Heinen, Matthias ; Vrabec, Jadran (2018-12-21)

An analytical solution of a model fluid’s time behavior, known as the Stefan problem, is presented. A scenario is investigated in which a planar two-component liquid film is continuously evaporating into a thermodynamically non-ideal vapor phase. Evaporation is initiated and maintained by a spatial chemical potential gradient, while its rate is limited by the components’ diffusion fluxes across...

Do ternary liquid mixtures exhibit negative main Fick diffusion coefficients?

Kozlova, S. ; Mialdun, Aliaksandr ; Ryzhkov, I. ; Janzen, Tatjana ; Vrabec, Jadran ; Shevtsova, Valentina (2019-01-07)

Experimental data on Fick diffusion coefficients of ternary and higher mixtures depend on the reference frame; those which are in common use are associated with the average velocity either with respect to volume, mass or mole number. In this study, the dependence of diffusion coefficients on the reference frame is thoroughly analyzed for three ternary mixtures of different types. The first one,...

Digitalization in Thermodynamics

Forte, Esther ; Jirasek, Fabian ; Bortz, Michael ; Burger, Jakob ; Vrabec, Jadran ; Hasse, Hans (2019-01-08)

Digitalization is about data and how they are used. This has always been a key topic in applied thermodynamics. In the present work, the influence of the current wave of digitalization on thermodynamics is analyzed. Thermodynamic modeling and simulation is changing as large amounts of data of different nature and quality become easily available. The power and complexity of thermodynamic models ...

Thermodynamic Speed of Sound Data for Liquid and Supercritical Alcohols

Javed, Muhammad Ali ; Baumhögger, Elmar ; Vrabec, Jadran (2019-02-28)

Because of their caloric and thermal nature, speed of sound data are vital for the development of fundamental Helmholtz energy equations of state for fluids. The present work reports such data for methanol, 1-propanol, 2-propanol, and 1-butanol along seven isotherms in the temperature range from 220 to 500 K and a pressure of up to 125 MPa. The overall expanded uncertainty varies between 0.07% ...

Nutrient recycling from sanitation and energy systems to the agroecosystem - Ecological research on case studies in Karagwe, Tanzania

Krause, Ariane ; Kaupenjohann, Martin ; George, Eckhard ; Köppel, Johann (2015)

Open cycles of organic carbon and nutrients cause soil degradation. Procedures such as ecological sanitation (EcoSan), bioenergy and Terra Preta practice (TPP) can contribute to closing nutrient cycles and may, in addition, sequester carbon. This paper introduces three projects in Karagwe, Tanzania, and their applied approach of integrated resource management to capture carbon and nutrients fro...