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The interest in applying Additive Manufacturing (AM) technology has grown due to its ability to produce complex parts with high flexibility, serving as an alternative to conventional manufacturing processes. However, the poor surface quality and limited dimensional accuracy of AM parts often necessitate post-processing such as machining, grinding, and polishing. Titanium, specifically Ti6Al4V alloy, is frequently used in AM technology. This study compares the machinability of AM Ti6Al4V parts...
This thesis presents statistical methods and analysis regarding the surface properties and processes of the lunar surface using reflectance spectroscopy. The first process of interest is the diurnal variations of OH/H2O on the Moon. Closely linked to this are lunar swirls, which are the second major science topic in this work. Thirdly, we investigate the mineral composition and space weathering to understand the first two processes. The solar wind contains hydrogen that forms hydroxyl and is...
Large area manufacturing processes of thin films such as large-area vacuum roll-to-roll coating of dielectric and gas permeation barrier layers in industry require a precise control of e.g. film thickness, homogeneity, chemical compositions, crystallinity and surface roughness. In order to determine these properties in real time, hyperspectral imaging is a novel, cost-efficient, and fast tool as in-line technology for large-area quality control. We demonstrate the application of hyperspectral...
Precise modification of a chemical site in a molecule at the single-atom level is one of the most elegant yet difficult transformations in chemistry. A reagent specifically designed for chemoselective introduction of monoatomic carbon is a particularly formidable challenge. Here we report a straightforward, azide-free synthesis of a crystalline and isolable diazophosphorus ylide Ph3PCN2, a stable compound with a carbon atom bonded to two chemically labile groups, triphenylphosphine (PPh3) and...
Beam quality Q = Z2/E (Z = ion charge, E = energy), an alternative to the conventionally used linear energy transfer (LET), enables ion-independent modeling of the relative biological effectiveness (RBE) of ions. Therefore, the Q concept, i.e. different ions with similar Q have similar RBE values, could help to transfer clinical RBE knowledge from better-studied ion types (e.g. carbon) to other ions. However, the validity of the Q concept has so far only been demonstrated for low LET values. ...
Actin subunits in filaments exhibit accelerated ATP hydrolysis compared to monomers. The subsequent slow phosphate (Pi) release results in an age-dependent distribution of ADP-Pi and ADP subunits within the filament. This stochastic process prevents newer regions from severing, as turnover occurs primarily in older sections rich in ADP subunits. However, the mechanism underlying Pi release from actin filament cores remains elusive. In the initial portion of this study, we present the mechanis...
Chlorine-35 is among the few nuclides that provide an experimental handle on the anion dynamics in choline based deep eutectic solvents. By combining several nuclear magnetic resonance (NMR) techniques, the present work examines the Cl− motions within glyceline, a glycerol : choline chloride 2 : 1 solution, in a large temperature range down to the glass transition temperature Tg. The applied methods include spin relaxometry, second-order line shape analysis, as well as two-dimensional central...
The fabrication and characterization of steep slope transistor devices based on low-dimensional materials requires precise electrostatic doping profiles with steep spatial gradients in order to maintain maximum control over the channel. In this proof-of-concept study we present a versatile graphene heterostructure platform with three buried individually addressable gate electrodes. The platform is based on a vertical stack of embedded titanium and graphene separated by an intermediate oxide t...
Biomembranes are a key component of all living systems. Most research on membranes is restricted to ambient physiological conditions. However, the influence of extreme conditions, such as the deep subsurface on Earth or extraterrestrial environments, is less well understood. The deep subsurface of Mars is thought to harbour high concentrations of chaotropic salts in brines, yet we know little about how these conditions would influence the habitability of such environments. Here, we investigat...
This research investigates the relationship between mobility and justice in the context of Nairobi. Deriving from Amartya Sen's notion that justice addresses remediable injustices, the study explores justice as a dynamic concept influenced by diverse cultures, political ideologies, and philosophical paradigms. Spatial planning is taken as a canvas for these philosophical debates, manifesting in the spatial distribution of resources. Justice in relation to mobility is invoked and performed in...
Governments have developed, agreed, and often embraced ambitious targets to meet sustainability and climate change demands. The use of land is foundational for long-term success and one of the most crucial resources where absolute limits of development become tangible. In Europe, success in stopping the expansion of settlement uses through building on natural or agricultural land remains limited in scope and speed. While planning instruments could be open for versatile uses, a pro-growth path...
This thesis addresses emerging ICT-based stability risks for cyber-physical energy systems (CPESs) in light of the increasingly complex task of coordinating modern generation and consumption assets in power grids. It does so by identifying cyber-physical services as the main drivers of interdependence first. It then provides a general approach on how to assess such a service's dependence on data in general and its sensitivity towards the high-level ICT error categories "latency", "data loss" ...
In this study, the opportunities and challenges for retailers in the course of the digital transformation were examined from three perspectives: the retailer perspective, the customer perspective, and the platform perspective. The first chapter provides a historical overview of the development of retail, followed by a definition of key terms and a characterisation of the study's subject. Furthermore, the first chapter also derives the guiding research questions for the subsequent chapters. C...
Core-crosslinked micelles have become an important class of materials for biomedical applications. However, there has been little work attempting to quantify the efficiency of the core crosslinking reaction, instead residual polymers are usually removed by dialysis. In this work we have prepared core crosslinked micelles based on poly(2-ethyl-2-oxazoline)-block-poly(n-butyl acrylate-co-D,L-homocysteine thiolactone acrylamide). Core crosslinking was examined by the addition of six different di...
Solvated in propylene carbonate, viscous phenol is studied using dielectric spectroscopy and shear rheology. In addition, several oxygen-17 and deuteron nuclear magnetic resonance (NMR) techniques are applied to specifically isotope labeled equimolar mixtures. Quantum chemical calculations are used to check the electrical field gradient at phenol's oxygen site. The chosen combination of NMR methods facilitates the selective examination of potentially hydrogen-bond related contributions as wel...
We developed an aqueous multiphase system for the synthesis of biobased alkyl amines via palladium-catalysed telomerisation based on the terpene β-myrcene. Ethanol was employed as a harmless co-solvent. With this “green” switchable multiphase solvent system, the recycling of the expensive homogeneous catalyst was successfully enabled by self-separating products at room temperature. The total turnover number (TON) was increased to almost 12 000 over 9 runs, with high selectivities towards the ...
Das umfangreiche Werk der Architekten Otto von Estorff und Gerhard Winkler ist nach der politischen Wende im Jahr 1989 eher zufällig entdeckt worden. Sie zählten in der Zeit von 1926-1948 zu den bekanntesten Architekten in Potsdam und Umgebung. Bedingt durch die Umwälzungen nach dem Ende des 2.Weltkriegs und die damit verbundenen politischen Veränderungen verlegte Otto von Estorff seinen Wohnsitz von Potsdam nach Menden, der Heimatstadt seiner Ehefrau. Gerhard Winkler befand sich zu diesem Ze...
Dieser Leitfaden entstand aus der Zusammenarbeit zwischen dem Kompetenzzentrum digitale barrierefreiheit.nrw und dem Projekt degree 5.0, beide angesiedelt an der Technischen Universität Dortmund. Die Kooperation dieser beiden Einrichtungen ermöglichte es, eine umfassende Anleitung zur Gestaltung von Audiodeskription für Videos zu entwickeln.
Im Rahmen der gesetzlichen Neuregelung der Kinder- und Jugendhilfe im Sinne einer Gesamtzuständigkeit für junge Menschen mit und ohne Behinderungen soll die Ausgestaltung der zukünftigen Regelungen hinsichtlich der Bestimmung der Leistungsberechtigten, Art und Umfang der Leistungen, der Ausgestaltung der Verfahren und der Kostenbeteiligung erfolgen. Fachdebatten dazu werden seit Jahren intensiv geführt. Von hoher Relevanz und öffentlichem Interesse ist es daher, die vielfältig diskutierten Re...
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