Technische Universität Berlin

14018 Items

Recent Submissions
In situ X-ray diffraction during laser powder bed fusion

Schmeiser, Felix (2022)

The Laser Powder Bed Fusion (LPBF) process is a generative manufacturing process, where a focused laser beam selectively melts a thin layer of powder. The three-dimensional component is created layer by layer by repeating the application of a new powder layer followed by laser exposure. LPBF is becoming increasingly widespread and is the subject of much research, as the resulting material prope...

Nonequilibrium Bose condensation in a pumped dye-filled photonic cavity

Vlaho, Martina (2022)

An effectively two-dimensional photon gas trapped in a dye-filled microcavity can undergo thermalization and equilibrium-like Bose-Einstein condensation. However, given the inherently driven-dissipative nature of this system, it can exhibit a complex interplay between the thermalizing influence of the environment given by the dye solution and the pump and loss processes driving the system out o...

Adjoint-based monopole synthesis of sound sources with complex directivities

Hölter, Arne Birk (2022)

Numerical time domain methods are continuously improving and gain in importance in virtual acoustics. The accurate modeling of directive sound sources is a prerequisite for acoustical simulations. In contrast to frequency domain methods, the directivity pattern of sound sources cannot be analytically implemented in the time domain directly. The sound sources are rather approximated by the super...

Serial and parallel processing in multitasking: Concepts and the impact of interindividual differences on task and stage levels.

Brüning, Jovita ; Koob, Valentin ; Manzey, Dietrich ; Janczyk, Markus (2022)

In multitasking research, a central question revolves around whether humans can process tasks in parallel. What “in parallel” refers to, however, differs between research perspectives and experimental approaches. From a task-level perspective, parallel processing can be conceived as to whether complete tasks are processed in an overlapping manner and how this impacts task performance. In contra...

Thermoresponsive self-assembly of twofold fluorescently labeled block copolymers in aqueous solution and microemulsions

Hechenbichler, Michelle ; Prause, Albert ; Gradzielski, Michael ; Laschewsky, André (2021-11-04)

A nonionic double hydrophilic block copolymer with a long permanently hydrophilic and a small thermoresponsive block is synthesized by reversible addition–fragmentation chain-transfer polymerization (RAFT). By employing a specifically designed chain-transfer agent, the polymer is functionalized with complementary end groups which are suited for Förster resonance energy transfer (FRET). The end ...

How well does the Tang-Toennies potential represent the thermodynamic properties of argon?

Nitzke, Isabel ; Pohl, Sven ; Thol, Monika ; Span, Roland ; Vrabec, Jadran (2022-05-23)

The potential function suggested by Tang and Toennies is parametrised to represent the thermodynamic properties of argon. The fit of its parameters is carried out on the basis of different data obtained by molecular dynamics simulation and integration of Mayer's f function. Apart from usual optimisation procedures, an efficient strategy based on reduced units is employed. The Tang-Toennies mode...

Impact of aging on the energy efficiency of household refrigerating appliances

Paul, Andreas ; Baumhögger, Elmar ; Elsner, Andreas ; Reineke, Michael ; Hueppe, Christian ; Stamminger, Rainer ; Hoelscher, Heike ; Wagner, Hendrik ; Gries, Ulrich ; Becker, Wolfgang ; Vrabec, Jadran (2021-12-30)

The parameters required to calculate the energy efficiency of household refrigerating appliances (i.e. refrigerators, freezers and their combinations) are determined by standard measurements. According to regulations, these measurements are carried out when the appliances are new. It is known from previous studies that various technical aging mechanisms can increase electrical energy consumptio...

Alterungsverhalten wasserbasierter intumeszierender Beschichtungen infolge künstlicher Bewitterung

Daus, Lars-Hendrik (2022)

Intumeszierende Beschichtungen (I.B.) werden im Brandschutz eingesetzt um die Feuerwiderstandsdauer von Bauteilen zu erhöhen. Im Falle eines Brandes entfallten I.B. ihre schützende Funktion indem sie aufschäumen wenn sie erhitzt werden und zu einer Isolationsschicht anschwellen. Zu diesem Zweck sind in den Anstrichen zu hohen Massenanteilen verschiedene Substanzen enthalten, welche miteinander ...

Visualization and auralization of features learned by neural networks for musical instrument recognition

Krusche, Anton (2022)

In computer vision a number of feature visualization techniques were developed to make convolutional networks more interpretable. For audio classification those methods are used as well but are not as extensively investigated. This thesis picks up on that and investigates to which extent a selection of feature visualization methods originally developed with image recognition in mind can help to...

Life cycle assessment of fusion welding processes—A case study of resistance spot welding versus laser beam welding

Pittner, Andreas ; Rethmeier, Michael (2022-05-17)

The high amount of resource consumption of fusion welding processes offers the potential to reduce their environmental impact. While the driving forces are known from a qualitative perspective, the quantitative assessment of the crucial parameters is not a trivial task. Therefore, herein, a welding-specific methodology to utilize life cycle assessment as a tool for evaluating the environmental ...

MODUS-COVID Bericht vom 28.06.2022

Müller, Sebastian Alexander ; Charlton, William ; Ewert, Ricardo ; Paltra, Sydney ; Rakow, Christian ; Rehmann, Jakob ; Conrad, Tim ; Schütte, Christof ; Nagel, Kai (2022-06-28)

In diesem Bericht widmen wir uns zuerst der neuen Omikron BA.5-Variante und der damit einhergehenden Sommerwelle. Basierend auf dem aktuellen Stand der Forschung bezüglich Übertragbarkeit und Krankheitsschwere von BA.5 berechnet unser Modell zwar steigende Infektionszahlen, die daraus resultierende “Welle von Infektionen” wird das Gesundheitssystem allerdings voraussichtlich nicht überlasten. ...

Long-distance air pressure differences correlate with European rain

Müller-Plath, Gisela ; Lüdecke, Horst-Joachim ; Lüning, Sebastian (2022-06-17)

Precipitation in Europe shows natural fluctuations that differ considerably between seasons and geographical regions. A number of studies have linked local or seasonal rainfall variability to various long-distance air pressure differences in north–south or west–east direction. This paper presents the first continent-wide analysis of European rainfall variability on a month-by-month and country-...

Towards robust data-driven reduced-order modelling for turbulent flows: application to vortex-induced vibrations

Schubert, Yannick ; Sieber, Moritz ; Oberleithner, Kilian ; Martinuzzi, Robert (2022-05-23)

This work presents a robust method that minimises the impact of user-selected parameter on the identification of generic models to study the coherent dynamics in turbulent flows. The objective is to gain insight into the flow dynamics from a data-driven reduced order model (ROM) that is developed from measurement data of the respective flow. For an efficient separation of the coherent dynamics,...

The effect of alterations of schizophrenia-associated genes on gamma band oscillations

Metzner, Christoph ; Mäki-Marttunen, Tuomo ; Karni, Gili ; McMahon-Cole, Hana ; Steuber, Volker (2022-04-28)

Abnormalities in the synchronized oscillatory activity of neurons in general and, specifically in the gamma band, might play a crucial role in the pathophysiology of schizophrenia. While these changes in oscillatory activity have traditionally been linked to alterations at the synaptic level, we demonstrate here, using computational modeling, that common genetic variants of ion channels can con...

Molecular basis of antibiotic self-resistance in a bee larvae pathogen

Dang, Tam ; Loll, Bernhard ; Müller, Sebastian ; Skobalj, Ranko ; Ebeling, Julia ; Bulatov, Timur ; Gensel, Sebastian ; Göbel, Josefine ; Wahl, Markus C. ; Genersch, Elke ; Mainz, Andi ; Süssmuth, Roderich D. (2022-04-29)

Paenibacillus larvae, the causative agent of the devastating honey-bee disease American Foulbrood, produces the cationic polyketide-peptide hybrid paenilamicin that displays antibacterial and antifungal activity. Its biosynthetic gene cluster contains a gene coding for the N-acetyltransferase PamZ. We show that PamZ acts as self-resistance factor in Paenibacillus larvae by deactivation of paeni...

Lichen cell factories: methods for the isolation of photobiont and mycobiont partners for defined pure and co-cultivation

Zakeri, Zakieh ; Junne, Stefan ; Jäger, Fabia ; Dostert, Marcel ; Otte, Volker ; Neubauer, Peter (2022-05-09)

Background: Due to their huge biodiversity and the capability to produce a wide range of secondary metabolites, lichens have a great potential in biotechnological applications. They have, however, hardly been used as cell factories to date, as it is considered to be difficult and laborious to cultivate lichen partners in pure or co-culture in the laboratory. The various methods used to isolate ...

Inertial stochastic PALM and applications in machine learning

Hertrich, Johannes ; Steidl, Gabriele (2022-04-22)

Inertial algorithms for minimizing nonsmooth and nonconvex functions as the inertial proximal alternating linearized minimization algorithm (iPALM) have demonstrated their superiority with respect to computation time over their non inertial variants. In many problems in imaging and machine learning, the objective functions have a special form involving huge data which encourage the application ...

Springback effect and structural features during the drying of silica aerogels tracked by in-situ synchrotron X-ray scattering

Zemke, Fabian ; Scoppola, Ernesto ; Simon, Ulla ; Bekheet, Maged F. ; Wagermaier, Wolfgang ; Gurlo, Aleksander (2022-05-09)

The springback effect during ambient pressure drying of aerogels is an interesting structural phenomenon, consisting of a severe shrinkage followed by almost complete re-expansion. The drying of gels causes shrinkage, whereas re-expansion is believed to be linked to repelling forces on the nanoscale. A multi-scale structural characterization of this significant volume change is key in controlli...

Existence of solutions for singular double phase problems via the Nehari manifold method

Liu, Wulong ; Dai, Guowei ; Papageorgiou, Nikolaos S. ; Winkert, Patrick (2022-04-18)

In this paper we study quasilinear elliptic equations driven by the double phase operator and a right-hand side which has the combined effect of a singular and of a parametric term. Based on the fibering method by using the Nehari manifold we are going to prove the existence of at least two weak solutions for such problems when the parameter is sufficiently small.

Radical artifactualism

Oliveira, Guilherme Sanches de (2022-06-02)

A powerful idea put forward in the recent philosophy of science literature is that scientific models are best understood as instruments, tools or, more generally, artifacts. This idea has thus far been developed in combination with the more traditional representational approach: accordingly, current artifactualist accounts treat models as representational tools. But artifactualism and represent...