1,487 research outputs found
Characterization of Fractal Structures by Spray Flame Synthesis Using X-ray Scattering
In this work, we take on an in-depth characterization of the complex particle structures made by spray flame synthesis. Because of the resulting hierarchical aggregates, very few measurement techniques are available to analyze their primary particle and fractal properties. Therefore, we use small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) to investigate the influence of the precursor concentration on the fractal structures of zirconia nanoparticles. The combination of information gained from these measurement results leads to a detailed description of the particle system, including the polydispersity and size distribution of the primary particles. Based on our findings, unstable process conditions could be identified at low precursor concentrations resulting in the broadest size distribution of primary particles with rough surfaces. Higher precursor concentrations lead to reproducible primary particle sizes almost independent of the initial precursor concentration. Regarding the fractal properties, the typical shape of aggregates for aerosols is present for the investigated range of precursor concentrations. In conclusion, the consistent results for SAXS and TEM show a conclusive characterization of a complex particle system, allowing for the identification of the underlying particle formation mechanism
Adopting different wind-assisted ship propulsion technologies as fleet retrofit : An agent-based modeling approach
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Maximal coherence and the resource theory of purity
The resource theory of quantum coherence studies the off-diagonal elements of a density matrix in a distinguished basis, whereas the resource theory of purity studies all deviations from the maximally mixed state. We establish a direct connection between the two resource theories, by identifying purity as the maximal coherence which is achievable by unitary operations. The states that saturate this maximum identify a universal family of maximally coherent mixed states. These states are optimal resources under maximally incoherent operations, and thus independent of the way coherence is quantified. For all distance-based coherence quantifiers the maximal coherence can be evaluated exactly, and is shown to coincide with the corresponding distance-based purity quantifier. We further show that purity bounds the maximal amount of entanglement and discord that can be generated by unitary operations, thus demonstrating that purity is the most elementary resource for quantum information processing
Water-in-Fluorocarbon Nanoemulsions Stabilized by Phospholipids and Characterized for Pharmaceutical Applications
Fluorocarbons are one of the most promising hydrophobic phases for future pharmaceutical production processes and various biomedical applications. Yet, because of their specific characteristics such as high density and refractive index similar to water, analysis of water‐in‐fluorocarbon (w/fc) nanoemulsions remains a challenge. The present work examines w/fc nanoemulsions stabilized with phospholipids as natural emulsifiers and tackles the measuring problems of photon correlation spectroscopy (PCS) when used for investigation of fluorocarbon nanoemulsions. These emulsions are suitable to form liposomes via centrifugation and thus, are required to meet certain criteria such as stability and size. The results imply a stability of up to 4 weeks with an average size of 180 nm. The intensity mean diameter gained from PCS measurements shows large scattering directly after sonication which is due to gas bubbles from sonication. The number mean is not influenced by gas bubbles and gives a more accurate depiction of the produced nanoemulsions. These findings are supported by small‐angle X‐ray scattering data, which are additionally applied for liposome analysis measuring a size of approximately 60 nm
Thermodynamics of phantom black holes in Einstein-Maxwell-Dilaton theory
A thermodynamic analysis of the black hole solutions coming from the
Einstein-Maxwell-Dilaton theory (EMD) in 4D is done. By consider the canonical
and grand-canonical ensemble, we apply standard method as well as a recent
method known as Geometrothermodynamics (GTD). We are particularly interested in
the characteristics of the so called phantom black hole solutions. We will
analyze the thermodynamics of these solutions, the points of phase transition
and their extremal limit. Also the thermodynamic stability is analyzed. We
obtain a mismatch of the between the results of the GTD method when compared
with the ones obtained by the specific heat, revealing a weakness of the
method, as well as possible limitations of its applicability to very
pathological thermodynamic systems. We also found that normal and phantom
solutions are locally and globally unstable, unless for certain values of the
coupled constant of the EMD action. We also shown that the
anti-Reissner-Nordstrom solution does not posses extremal limit nor phase
transition points, contrary to the Reissner-Nordstrom case.Comment: 23 pages, version accepted for publication in Physical Review
Comparison of analogue and digital audio technology based on a production
Die nachfolgende Arbeit soll einen intensiven Einblick in die heutigen Audiotechniken der Tonstudios geben. Dabei sollen die Unterschiede von analoger und digitaler Audiotechnik erörtert und dargestellt werden. Dies erfolgt mit Hilfe einer Audioproduktion, die im Tonstudio Atlantis 3.0 durchgeführt wird. Es werden nicht nur die klanglichen Differenzen, sondern auch die Unterschiede in Verfahren, Kosten und Aufwand beleuchtet. Abschließend werden die resultierenden Vor- und Nachteile beider Systeme benannt und ein Fazit erstellt
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