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Toward quantitative low-energy ion scattering on CaSiO₃ from comparison to multiple-scattering-resolved dynamical binary collision approximation simulations
No full textWe perform Low-energy Ion Scattering with He ions ranging in energy from 1 keV to 3 keV on CaSiO₃ using a commercial electrostatic detector system and determine the charge fraction of scattered ions from comparison with binary collision approximation simulations. The simulations take composition changes due to surface cleaning Xe sputtering into account. Scattered He particles are separated in the simulation into single, dual, and multiple scattering trajectories. We find that the charge fraction of single and dual scattered He is about ten times higher than the one for multiple collisions. Our results show that the charge fraction of scattered He can be reliably extracted for different scattering regimes and that for a given He incidence energy, the entire scattered He spectrum can be modeled with only few constant parameters
Club-based mobility solutions. An analysis of car-sharing clubs in rural contexts, taking gender-related aspects into account
No full textDiese Diplomarbeit widmet sich der Analyse von Carsharing-Vereinen im ländlichen Raum Österreichs und untersucht dabei insbesondere die Rolle geschlechterspezifischer Aspekte in deren Gründung und Organisation. Ausgangspunkt ist die Frage, welche sozialen, ökologischen und ökonomischen Motive zur Entstehung solcher Initiativen führen und wie sich Genderdynamiken in der internen Struktur und im operativen Betrieb widerspiegeln.Die Untersuchung basiert auf einer qualitativen Fallstudie mit sieben Carsharing-Vereinen in Niederösterreich, Oberösterreich und Salzburg. Als zentrale Methode wurden leitfadengestützte Interviews mit Gründer:innen und Vorstandsmitgliedern durchgeführt, ergänzt durch Kontextinformationen aus öffentlich zugänglichen Quellen. Die Auswertung erfolgte mittels qualitativer Inhaltsanalyse und konzentriert sich auf drei Dimensionen: Gründungsmotive, interne Organisationsstrukturen und Rollenverteilung. Die Ergebnisse zeigen, dass Carsharing-Vereine überwiegend aus bürgerschaftlichem Engagement entstehen und ökologische Zielsetzungen mit sozialer Verantwortung verbinden. Frauen übernehmen in mehreren Fällen zentrale Leitungsfunktionen, sind jedoch in technischen Rollen weiterhin unterrepräsentiert. Traditionelle Geschlechterrollen wirken in der Aufgabenverteilung fort, während einzelne Vereine Ansätze zur Durchbrechung dieser Muster erkennen lassen. Genderspezifische Mobilitätsbedürfnisse wie flexible Buchungsoptionen, Kindersitze oder Sicherheitsaspekte werden bislang nur punktuell berücksichtigt.Aus raumplanerischer Perspektive verdeutlicht die Arbeit, dass vereinsbasierte Carsharing-Modelle nicht nur zur Reduktion des motorisierten Individualverkehrs beitragen, sondern auch soziale Teilhabe und regionale Entwicklung fördern können. Auf Basis der Analyse werden praxisorientierte Handlungsempfehlungen für Vereine, Gemeinden und die Landespolitik abgeleitet, die Maßnahmen zur Professionalisierung, zur Stärkung des Ehrenamts und zur Integration gendersensibler Kriterien in Förderprogramme umfassen. Damit liefert die Arbeit Impulse für die Weiterentwicklung gemeinschaftsbasierter Mobilitätsangebote und deren Einbettung in nachhaltige Mobilitätsstrategien im ländlichen Raum.This thesis analyzes carsharing associations in rural regions of Austria, with a particular focus on the role of gender-specific aspects in their establishment and organizational structures. The study addresses the question of which social, ecological, and economic motives drive the creation of such initiatives and how gender dynamics are reflected in internal structures and operational processes.The research is based on a qualitative case study of seven carsharing associations located in Lower Austria, Upper Austria, and Salzburg. Guided interviews with founders and board members were conducted as the primary method, complemented by contextual information from publicly available sources. The analysis, carried out using qualitative content analysis, focuses on three dimensions: founding motives, internal organizational structures, and role distribution.Findings reveal that carsharing associations predominantly emerge from civic engagement and combine ecological objectives with social responsibility. Women frequently assume key leadership roles, yet remain underrepresented in technical functions. Traditional gender roles continue to influence task allocation, although some associations show tendencies toward breaking these patterns. Gender-specific mobility needs such as flexible booking options, child seats, or safety considerations are addressed only selectively.From a spatial planning perspective, the study demonstrates that community-based carsharing models not only contribute to reducing private car ownership but also foster social inclusion and regional development. Based on these insights, the thesis derives practical recommendations for associations, municipalities, and regional policymakers, including measures to enhance professionalization, strengthen voluntary engagement, and integrate gender-sensitive criteria into funding programs. In doing so, the research provides valuable impulses for advancing community-based mobility solutions and embedding them within sustainable mobility strategies for rural areas
Characterization of TiVZrNb based High Entropy Alloys for Hydrogen Storage Applications
Get PDFThe aim of this work is to synthesise different high entropy alloys (HEAs) and to characterise them with respect to their hydrogen storage capacity and structural properties. The alloys are all based on TiVZrNb in different ratios and additionally with a fifth element added. The focus here was on a series of experiments involving aluminium. Five TiVZrNb HEAs were synthesised with 0, 5, 10, 15 and 20 at % Al. In addition, experiments were carried out with 5 at % chromium,manganese and germanium each. The technique of arc melting was used to synthesise the alloys. X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF) were used to characterise the purity and structure. To characterise the hydrogen storage properties, the samples were hydrogenated using high pressure hydrogen gas and subsequently analysed via thermogravimetric analysis (TGA). XRD was performed directly after synthesis, after hydrogenation and after de-hydrogenation. All XRD data were analysed using the Rietveld refinements method where possible. Furthermore, it is planned that the pressure composition isotherms will be measured through existing collaboration which will form the basis of futurework.All samples that were hydrogenated show good hydrogen absorption characteristics with H/Mratios up to 2,1 and wt % H values between 2,1 and 2,9, whereby the trend in the set with aluminium is towards better values with less Al. Desorption temperatures lie between 248,1and 304,8 °C. With regard to the purity of the samples, a clear trend can be observed: the higher the amount of Al, the lower the purity and the more phases occur.The second set of experiments shows similar results. The H/M ratios lie between 1,8 and 1,9with wt % H values of 2,5 to 2,7. The on set temperatures here are between 229,9 and 275,5 °C.For good purity, the samples containing Cr and Mn can be favoured here, the Ge containing sample shows formation of further phases and lower purity.The fundamentally good potential of these samples for use as hydrogen storage materials must be investigated by further analysis in order to be able to make precise statements about their usability.It should also be mentioned that a third set of experiments was carried out. This involved two samples based on the base alloy TiVZrNb with different element ratios with the aim of producing amorphous samples
Temporary Event Architecture - The Example of the Olympic Archery Venue in Brisbane 2032
No full textDie vorliegende Diplomarbeit untersucht Architekturkonzepte für temporäre Sportbauten im Kontext internationaler Großveranstaltungen mit dem Ziel, über die unmittelbare Nutzung hinausgehende städtebauliche, kulturelle und gesellschaftliche Mehrwerte zu generieren. Am Beispiel einer geplanten Bogenschießanlage für die Olympischen Spiele 2032 in Brisbane werden theoretische Analysen, Fallstudien, städtebauliche Untersuchungen sowie vor Ort gewonnene Erkenntnisse systematisch miteinander verknüpft. Der entworfene Ansatz berücksichtigt unterschiedliche Nutzungsphasen und verdeutlicht, wie temporäre Architektur funktionale Anforderungen erfüllen und zugleich nachhaltig in den urbanen Kontext integriert werden kann.This diploma thesis explores architectural concepts for temporary sports facilities in the context of major international events, with the aim of generating urban, cultural and social benefits that extend beyond their immediate use. A proposed archery venue for the 2032 Olympic Games in Brisbane is used as a case study to systematically combine theoretical analyses, case studies, urban investigations and insights gained on site. The resulting design approach considers the venue‘s different usage phases and demonstrates how temporary architecture can fulfil functional requirements while also making a sustainable contribution to the urban context
Quaternary terrace formation in response to climate, regional uplift and local normal faulting: The Danube terrace staircase of Vienna
No full textQuaternary terrace sequences can be observed along many mid to high latitudinal rivers, often reflecting a distinct, climate-related cyclicity of the fluvial system in uplifting regions. They are also essential landforms in many continental basins even though local basin subsidence may counteract an existing regional uplift trend. Glacial and periglacial processes may amplify events of river aggradation, with associated terraces providing clear stratigraphic markers. In this study, we explore the opposing lithospheric forces, regional uplift vs. local normal faulting, along a perialpine section of the Danube River, which is strongly affected by a 100-ka depositional cyclicity during the Quaternary. Within the city of Vienna, the Danube formed an extensive terrace staircase across a continental-scale normal fault. This fault demarcates the transition of the Eastern Alps and the Miocene Vienna Basin. Its Quaternary activity remained ambiguous and its impact on terrace configuration largely unexplored. Solifluction processes over several glacial-interglacial cycles typically led to thick colluvial deposits along terrace slopes, resulting, together with the anthropogenic overprint, in obliteration of the terrace morphology. To constrain terrace geometry, elevation and decipher fault kinematics we used electrical resistivity tomography, drill log and historical outcrop data. We applied morphostratigraphic age modelling supported by terrestrial cosmogenic radionuclide burial and luminescence dating to derive rates of uplift and subsidence. Results show how long-wavelength uplift and concomitant normal faulting have controlled terrace development and Quaternary landscape evolution. This study provides clear evidence for fault activity within the city of Vienna
Microstructural tailoring of Cr–Mn–Mo Nitrides through Si and Y alloying
No full textThis study investigates Si and Y alloying effects on microstructure and mechanical properties of Cr–Mn–Mo-based high- and medium-entropy nitride thin films fabricated by reactive DC magnetron sputtering, employing ab initio calculations and experimental analysis. Ab initio results show the unalloyed Cr–Mn–Mo–N system forms a stable fcc structure with negative formation energy, minimally affected by N vacancies. Alloying with Si, Y, or both further reduces formation energy, enhancing thermodynamic stability, especially at high Y concentrations. However, alloying comes with increased unit cell distortion, destabilising the crystal structure. Experiments reveal that Si and Y promote N incorporation, but complete stoichiometric metal-to-nitrogen ratios are not achieved, yielding N-vacant films. Structural analyses confirm the formation of a single-phase fcc solid solution, with lattice expansion and crystallite size refinement induced by increasing alloying concentrations. Atomic size mismatch is identified as the principal factor governing phase formation. Alloying enhances hardness without compromising elasticity, peaking at 20.5 GPa in Si-alloyed film due to nanocrystallinity, N incorporation, and strong nitride covalent bonding
Singularity, weighted uniform approximation, intersections and rates
No full textA classical argument was introduced by Khintchine in 1926 in order to exhibit the existence of totally irrational singular linear forms in two variables. This argument was
subsequently revisited and extended by many authors. In the present paper we adapt Khintchine's argument to show that the sets of very singular matrices and their weighted analogues intersect many manifolds and fractals, and
have strong intersection properties. We also obtain new bounds on the rate of singularity which can be attained by column vectors in analytic submanifolds of dimension at least 2 in n-dimensional space