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Nanocrystalline silicon nanoparticles with a median crystallite size of 3–4 nm and several crystalline phases and defects (e.g. twin boundary) were produced by femtosecond laser processing of a SiO2/Si target in various organic fluids. Furthermore, a nanoscaled amorphous oxide layer and a few atomic layers of a graphite shell were detected in ethanol and 2-butanol correspondingly. The ultrafast laser pulses may manipulate nanostructures at the atomic level and generate a high density of defects; this may be correlated with significant thermal stresses on nanoparticles and rapid condensation of primary nanoparticles with high cooling rates. Size distribution width and a polydispersity index slightly increased with increasing laser fluence in ethanol. In 2-butanol, the maximum ablation volume was observed. The specific ablation rates in 2-butanol and ethanol were approximately five times higher than n-hexane. The lowest ablation efficiency in n-hexane can be associated with femtosecond laser-induced photolysis and pyrolysis of solvent molecules, as total energy deposition on the material may be reduced due to the formation of carbonaceous products. The roughened zones (average roughness of ∼400 nm) in circumferences of the ablated craters in 2-butanol may be related to a correlation between the erosive power of the vapour bubble collapse and higher pressure at the bubble wall in relatively high dynamic viscosity fluids. Furthermore, sputtering of a pristine surface by releasing nanoparticles from the collective collapse of up-flow vapour bubbles can also contribute to the generation of roughened regions.

Scanning electron microscopy (SEM) and profilometry of the crater morphology and ablation efficiency upon femtosecond laser ablation of Au-coated Ni targets in various fluids revealed a pronounced dependence on the ablation medium. For ethanol, a sufficient ablation efficiency was obtained, whereas for 2-butanol a higher efficiency indicated stronger laser-target interaction. Hierarchical features in the crater periphery pointed to asymmetrical energy deposition or a residual effect of the Coulomb-explosion-initiating ablation. Significant beam deviation in 2-butanol caused maximum multiple scattering at the crater bottom. The highest values of microstrain and increased grain size, obtained from Williamson-Hall plots, indicated the superposition of mechanical stress, defect formation and propagation of fatigue cracks in the crater circumference. For n-hexane, deposition of frozen droplets in the outer crater region suggested a femtosecond-laser-induced phase explosion. A maximum ablation depth occurred in water, likely due to its high cooling efficiency. Grazing incidence micro X-ray diffraction (GIXRD) of the used target showed residual carbon and partial surface oxidation. The produced nanoparticle colloids were examined by multiangle dynamic light scattering (DLS), employing larger scattering angles for higher sensitivity toward smaller nanoparticles. The smallest nanoparticles were obtained in 2-butanol and ethanol. In n-hexane, floating carbon flakes originated from femtosecond-laser-induced solvent decomposition.

Ein gezielter Einsatz von passender Leistungsdiagnostik im Spitzensport bringt viele Vorteile mit sich. Die regelmäßige Durchführung von Testbatterien, kann bei der Gestaltung des Trainings hilfreich sein, bietet einen Überblick über den Trainingszustand der Athleten und trägt in weiterer Folge zur Vermeidung von Verletzungen bei. Doch viele bereits bestehende sportmotorische Testbatterien im Alpinen Skirennlauf erfordern teures oder speziell entwickeltes Equipment, welches für kleinere Verbände in vielen Fällen nicht leistbar ist bzw. nicht zur Verfügung steht.Das Ziel dieser Arbeit ist die Erstellung einer Testbatterie, für die Nachwuchs- und Anschlusssportler des liechtensteinischen Skiverbandes (LSV), welche unter Verwendung von einfachen Materialen durchgeführt werden kann und trotzdem eine hohe Aussagekraft, bezüglich der möglichen skifahrerischen Leistung, liefert. In den Trainingsalltag integriert, sollen die Testungen dazu genutzt werden, um die Wirkung des durchgeführten Trainings überprüfen, die Athleten des LSV besser untereinander vergleichen, eventuell vorhandene Defizite erkennen und einen Zusammenhang zur möglichen skifahrerischen Leistung herstellen zu können.Die erstellte Testbatterie konnte in Kooperation mit dem LSV und deren Nachwuchssportlern (N=21) durchgeführt werden. Die erhobenen Testergebnisse wurden in weiterer Folge im Programm Microsoft Excel verarbeitet. Zur besseren Übersicht und Darstellung der Ergebnisse dienen teilweise Standarddiagramme des Programmes, es wurden aber auch, in Absprache mit den Trainern, individuelle Auswertungsvarianten entwickelt.Es zeigt sich, dass die Auswertungsmöglichkeiten individuell und zielgruppenspezifisch gestaltet werden können. Für die Erfordernisse der Sportpraxis, insbesondere für den Alpinen Skirennlauf, sind sicherlich noch weiterführende, auch variable Tests zu konzipieren, um eine möglichst gute Übertragung der erhobenen Werte in die Trainingsplanung und Steuerung gewährleisten zu können. A focused use of accurate performance diagnostics in elite sports can bring many significant advantages. A regular and consistent implementation of test batteries can be helpful when designing training programs, gives an overview of the physical condition of the athlete and can subsequently serve as an injury prevention tool. However, many of the existing test batteries which are used in the area of alpine ski racing require expensive and specifically developed equipment, which many of the smaller associations cannot afford or are not available to them.The goal of this thesis is to design a test battery for youth- and prospective athletes of the Liechtenstein skiing association (LSV), which can be implemented with the use of simple tools and yet shows high validity in relation to skiing performance. When integrated into the everyday training schedule, the tests should be used to monitor the effects of the training, to better compare the athletes of the LSV internally, to recognize possible deficits of individual athletes and to make connections to potential skiing performances.The fully developed test battery was implemented in cooperation with the LSV and their youth-athletes (N=21). The accumulated test results were further processed in Microsoft Excel. For a better overview and display of results default diagrams of the program were used, however, in consultation with trainers, individual evaluation variants were also developed.The implementation of the test battery has shown that the evaluation options can be designed according to individual athletes but also for target specific groups. However, the practical requirements of everyday sports, especially in alpine ski racing, definitely call for the design of further tests, in order to ensure that the collected results can be transferred onto the planning and control of training programs with the utmost precision. Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüft Abweichender Titel laut Übersetzung des Verfassers/der Verfasserin Karl-Franzens-Universität Graz, Masterarbeit, 2021

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This study aims to investigate the physical and chemical characterization of six fly ash samples obtained from different municipal solid waste incinerators (MSWIs), namely grate furnaces, rotary kiln, and fluidized bed reactor, to determine their potential for CO2 and thermochemical energy storage (TCES). Representative samples were characterized via simultaneous thermal analysis (STA) in different atmospheres, i.e., N2, air, H2O, CO2, and H2O/CO2, to identify fly ash samples that can meet the minimum requirements, i.e., charging, discharging, and cycling stability, for its consideration as TCES and CO2-storage materials and to determine their energy contents. Furthermore, other techniques, such as inductively coupled plasma optical emission spectroscopy, X-ray fluorescence (XRF) spectrometry, X-ray diffraction (XRD), scanning electron microscopy, leachability tests, specific surface area measurement based on the Brunauer&ndash, Emmett&ndash, Teller method, and particle-size distribution measurement, were performed. XRF analysis showed that calcium oxide is one of the main components in fly ash, which is a potentially suitable component for TCES systems. XRD results revealed information regarding the crystal structure and phases of various elements, including that of Ca. The STA measurements showed that the samples can store thermal heat with energy contents of 50&ndash, 394 kJ/kg (charging step). For one fly ash sample obtained from a grate furnace, the release of the stored thermal heat under the selected experimental conditions (discharging step) was demonstrated. The cycling stability tests were conducted thrice, and they were successful for the selected sample. One fly ash sample could store CO2 with a storage capacity of 27 kg CO2/ton based on results obtained under the selected experimental conditions in STA. Samples from rotary kiln and fluidized bed were heated up to 1150 &deg, C in an N2 atmosphere, resulting in complete melting of samples in crucibles, however, other samples obtained from grate furnaces formed compacted powders after undergoing the same thermal treatment in STA. Samples from different grate furnaces showed similarities in their chemical and physical characterization. The leachability test according to the standard (EN 12457-4 (2002)) using water in a ratio of 10 L/S and showed that the leachate of heavy metals is below the maximum permissible values for nonhazardous materials (except for Pb), excluding the fly ash sample obtained using fluidized bed technology. The leachate contents of Cd and Mn in the fly ash samples obtained from the rotary kiln were higher than those in other samples. Characterization performed herein helped in determining the suitable fly ash samples that can be considered as potential CO2-storage and TCES materials.

Aerosols can act as cloud condensation nuclei and/or ice-nucleating particles (INPs), influencing cloud properties. In particular, INPs show a variety of different and complex mechanisms when interacting with water during the freezing process. To gain a fundamental understanding of the heterogeneous freezing mechanisms, studies with proxies for atmospheric INPs must be performed. Graphene and its derivatives offer suitable model systems for soot particles, which are ubiquitous aerosols in the atmosphere. In this work, we present an investigation of the ice nucleation activity (INA) of different types of graphene and graphene oxides. Immersion droplet freezing experiments as well as additional analytical analyses, such as X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy, were performed. We show within a group of samples that a highly ordered graphene lattice (Raman G band intensity >50%) can support ice nucleation more effectively than a lowly ordered graphene lattice (Raman G band intensity

In this work, we employed a step-by-step sol-gel process to controllably deposit ultra-thin layers of SiO2 on anatase nanoparticles in the range between 0 and 1 nm. The deposition was confirmed by TEM, EDX, and ATR-FTIR (e.g., Ti-O-Si band at 960 cm-1). Zeta potential measurements unravelled a continuous change in surface charge density with increasing silica shell thickness. The photocatalysts were evaluated towards adsorption and degradation of positively-charged and negatively-charged dyes (methylene blue, methyl orange) under UV illumination. The growth mechanism follows the Stranski&ndash, Krastanov model with three thickness regimes: (a) Flat islands (first step), (b) mono/bilayers (second/third step), and (c) regular thick films (fourth/fifth step). The results suggest different rate limiting processes for these regimes: (a) For the thinnest scenario, acidic triple-phase boundaries (TPBs) increase the activity for both dyes with their accessibility being the rate limiting step, (b) for continuous mono/bilayers, dye adsorption on the negatively-charged SiO2 shells becomes the rate liming step, which leads to a stark increase in activity for the positively-charged MB and a decrease for MO, (c) for thicker shells, the activity decreases for both dyes and is limited by the charge transport through the isolating shells.

The abstract is available here: https://uscholar.univie.ac.at/o:930864

This chapter reviews the current status of the research on the electronic properties of single-walled carbon nanotubes (SWCNTs) filled with metal halogenides and metallocenes and growth kinetics of inner SWCNTs inside metallocene-filled nanotubes. The chapter starts with the description of the peculiarities of the synthesis of metal halogenide-filled SWCNTs, comparison of different filling methods, their advantages, disadvantages, and restrictions. Then, we comprehensively summarize, compare, and critically discuss the recent studies on the electronic properties of metal halogenide-filled SWCNTs. After that, the synthesis methods of metallocene-filled SWCNTs are described and the results of the investigation of the growth kinetics of inner SWCNTs inside the filled nanotubes are summarized. Then, the reports dedicated to the investigation of the electronic properties of metallocene-filled SWCNTs are reviewed. Finally, potentials for future research, development, and application of filled SWCNTs are highlighted.

We demonstrate a unique route towards hierarchical assemblies of mesoporous TiO2 and CNT/TiO2 photocatalysts by a combination of electrospinning and sol–gel methods. The resulting materials exhibit a mesoporous network of highly crystalline, well-connected inorganic nanocrystals with an order of magnitude higher photocatalytic activity than individualised TiO2 nanoparticles. The in-situ combination of small amounts of MWCNTs with TiO2 to form an electrospun CNT/TiO2 hybrid further enhanced the oxide photoactivity considerably, reaching hydrogen evolution rates of 1218 μmol/h in water splitting in the presence of sacrificial reagents under UV irradiation. We also discuss the effect of oxygen vacancies on the oxide crystallisation and phase transformation. These vacancies lead to inter-bandgap states and a lower flat band potential that facilitates the photocatalytic process.