Experiments on the Behavior of the Filter Stability of Aggregates in Unbound Block Pavement Superstructures

In der vorliegenden Diplomarbeit wurde die Filterstabilität zwischen Gesteinskörnungen innerhalb des Schichtenaufbaus von ungebundenen Pflasterbefestigungen untersucht. Ziel war es, zu überprüfen, ob die in der österreichischen Richtlinie RVS 08.18.01 empfohlenen Sieblinienkombinationen zwischen Fugen- und Bettungsmaterial in der Praxis ausreichend filterstabil sind, um Materialverlagerungen und daraus resultierende Schäden zu vermeiden.Der Fokus lag auf labortechnischen Untersuchungen, bei denen verschiedene Kombinationen von Fugen- und Bettungsmaterialien mechanisch-hydraulischer Belastung ausgesetzt wurden. Der dafür eingesetzte Versuchsaufbau wurde speziell entwickelt, um realitätsnahe Beanspruchungen zu simulieren, und hat sich in seiner Anwendung als zuverlässig und praxisnah erwiesen. Es wurden Veränderungen der Sieblinien analysiert und deren Auswirkungen auf die Filterstabilität bewertet. Ergänzend dazu erfolgte eine theoretische Bewertung anhand der in der RVS definierten geometrischen Filterkriterien – einerseits für mögliche Kombinationen von Fugen- und Bettungsmaterial für die Laborversuche, andererseits zusätzlich für die Untersuchung des Verhaltens zwischen Bettung und Tragschicht sowie zwischen oberer und unterer Tragschicht.Die Ergebnisse zeigen, dass die in der RVS empfohlenen Sieblinienkombinationen unter realitätsnahen Bedingungen als ausreichend filterstabil einzustufen sind. In Einzelfällen kam es jedoch zu Veränderungen der Sieblinien und Anzeichen von Kornverlagerungen, was auf ein potenzielles Risiko für Materialwanderung schließen lässt. Solche Beobachtungen unterstreichen die Bedeutung einer passenden Materialauswahl und können bei abweichenden Kombinationen eine ergänzende labortechnische Überprüfung erforderlich machen.Die Arbeit leistet damit einen wichtigen Beitrag zum Verständnis der Filterstabilität bei Pflasterbefestigungen und betont die Relevanz einer sorgfältig abgestimmten Materialwahl im ungebundenen Schichtenaufbau. Die in der österreichischen Richtlinie RVS 08.18.01 empfohlenen Sieblinien zeigten ein stabiles Verhalten unter dynamischer und hydraulischer Belastung, was ihre praktische Anwendbarkeit bestätigt. Um die langfristige Eignung dieser Materialkombinationen noch besser beurteilen zu können, wäre es sinnvoll, deren Einsatz im Baualltag systematisch zu erfassen und auszuwerten. Erkenntnisse aus der Praxis können dazu beitragen, bestehende Regelwerke gezielt weiterzuentwickeln und an unterschiedliche Anwendungsbedingungen anzupassen.This diploma thesis investigates the filter stability between unbound granular materials within the layer structure of paving constructions. The aim was to assess whether the grain size distributions recommended in the Austrian guideline RVS 08.18.01 for joint and bedding materials are sufficiently filter-stable under practical conditions to prevent material migration and resulting damage.The primary focus was on laboratory investigations in which various combinations of joint and bedding materials were subjected to combined mechanical and hydraulic loading. A purpose-built test setup was used to realistically simulate these loads and proved to be both reliable and practice oriented. Particular attention was given to changes in the grain size distributions and their impact on filter stability. In addition, a theoretical evaluation was carried out based on the geometric filter criteria defined in the RVS - both for the joint-bedding interface and for the transitions between bedding and base layers, as well as between the upper and lower base layers.The results indicate that the grain size combinations recommended in the RVS generally exhibit sufficient filter stability under realistic conditions. However, in some cases, changes in the grain size distribution and signs of particle migration were observed, indicating a potential risk of material displacement. These findings highlight the importance of well-matched material selection and suggest that deviations from standard combinations should be supported by additional laboratory testing.This study provides a valuable contribution to the understanding of filter stability in block pavement superstructures and emphasizes the importance of carefully coordinated material selection in unbound layer systems. The grain size distributions recommended by the Austrian guideline RVS 08.18.01 demonstrated stable behavior under dynamic and hydraulic loading, supporting their applicability in practice. To further assess the long-term suitability of these material combinations, it would be beneficial to systematically document and evaluate their use in real-world construction projects. Practical feedback could help refine existing standards and better adapt them to varying field conditions

Evaluation of ULS Bathymetry for Hydrodynamic Modelling

The importance of accurate and reliable DTMs are paramount for hydrodynamic modelling. Currently, bathymetry is either not considered or a simpler mathematical representation of the river is created from observed cross sections for hydrodynamic models. Topographic and Bathymetric LiDAR creates centimetre resolution bathymetry and topography. However, it has not been applied into large scale hydrodynamic modelling. Following a major flood event in September 2024, a large fieldwork campaign on the Pielach River, Lower Austria, was conducted to capture the environmental changes using Topographic-Bathymetric LiDAR. Metre resolution DTMs of the bathymetric and topographic environment were created to produce flood inundation maps from crewed and uncrewed aerial mapping systems. Using the observed flow data of the September 2024 storm, resulting flood models prove the inclusion of bathymetry can produce reliable flood models with depths of greater than 6 m modelled. Due to the lower flying altitude and tactical flight paths of ULSs, it is possible to identify regions occluded by vegetation that would otherwise be overlooked by crewed Airborne Laser Scanning methods to produce more reliable flood models

Predicting Matrix Phase Composition and Properties Using CALPHAD-Guided Thermokinetic Simulations with MatCalc

Steel represents the predominant construction material due to its versatile properties, which can be extensively modified through variations in composition and production processes. High-strength, low-alloy (HSLA) boron steels are particularly notable for their superior mechanical properties, achieved through precise microstructure control. Microalloying involves minute additions of elements such as Al, Ti, Nb, or V, forming nitrides, carbonitrides, and carbides. These elements exhibit a complex interplay, competing for nitrogen, with titanium showing the highest affinity, followed by boron and aluminum. This competition affects the formation and distribution of nitrides, which in turn impacts the steel microstructure and mechanical properties. Aluminum nitride (AlN) plays a crucial role in grain size control due to its strong pinning effect [1]. Titanium protects boron from forming BN and can facilitate the nucleation of acicular ferrite, thus enhancing toughness [2], but is also keen to result in a bimodal grain growth distribution and an abnormal grain growth phenomenon [3]. Boron, in small quantities of only several wt.-ppm., serves as an economical hardenability promoter [4]. The beneficial "boron effect" needs a comprehensive understanding of the interaction of boron atoms with aluminum and titanium, particularly regarding the competition over nitrogen [5]. Accurate thermodynamic descriptions of these subsystems are crucial for effective thermokinetic precipitation simulations, which predict trends validated through experimental characterization. This leads to a deeper understanding of the interplay of BN with other nitrides such as TiN or AlN, the quantification of dissolved boron in austenite, and the steel microstructure. We present a CALPHAD-based [6] thermokinetic simulation approach using the MatCalc [7] toolbox to investigate the matrix phase composition and properties across a wide range of alloy chemistries. By simulating large variations in chemical composition, we systematically explore the effects of alloying on phase stability, transformation kinetics, and mechanical properties. The accuracy of this method relies on well-calibrated thermodynamic databases and robust kinetic modeling, enabling reliable predictions of phase evolution under realistic processing conditions. This approach significantly reduces development time and minimizes the need for extensive experimental trials in alloy design. Furthermore, it offers the potential for real-time adaptation of process parameters during production, paving the way for more efficient and responsive manufacturing workflows. References 1. Wilson FG, Gladman T (1988) Aluminium Nitride in Steel. International Materials Reviews 33(1): 221–286. doi: 10.1179/imr.1988.33.1.221 2. Baker TN (2019) Titanium Microalloyed Steels. Ironmaking & Steelmaking 46(1): 1–55. doi: 10.1080/03019233.2018.1446496 3. Najafkhani F, Kheiri S, Pourbahari B et al. Recent Advances in the Kinetics of Normal/Abnormal Grain Growth: A Review. 1644-9665 21(1): 1–20. doi: 10.1007/s43452-021-00185-8 4. Sharma M, Ortlepp I, Bleck W (2019) Boron in Heat‐Treatable Steels: A Review. steel research international 90(11): 1900133. doi: 10.1002/srin.201900133 5. Führer M, Zamberger S, Seubert C et al. (2025) Experimental Investigation of the Interplay Between Al-, B-, and Ti-Nitrides in Microalloyed Steel and Thermodynamic Analysis. Metals 15(7): 705. doi: 10.3390/met15070705 6. Kaufman L, Bernstein H (1970) Computer calculation of phase diagrams. With special reference to refractory metals. Academic Press Inc, New York 7. (2024) Matcalc - Solid State and Kinetics Precipitation. https://www.matcalc.at/index.php/databases/open-databases. Accessed 29 Jul 202

Usage of advanced analytical techniques assessing the influence of Si on the stabilization of amorphous Al2O3-based thin films

Aluminium oxide (Al2O3) is a well-known thermally stable and insulating material employed in various applications as structural components and in thin film form. Al2O3 can be stabilized in several polymorphs in addition to an amorphous modification. The amorphous state of Al2O3 mainly exhibits interesting features, considering the absence of crystalline defects for the diffusion of charge carriers, which is paired with the difficulties in stabilizing crystalline Al2O3 during Physical Vapor Deposition (PVD). Therefore, in this study the influence of Si on the structural and chemical evolution of amorphous alumina-based thin films was systematically investigated using complementary advanced analytical techniques. The thin films (~ 350 nm) were produced via reactive High Power Impulse Magnetron Sputtering (HiPIMS) using Al-Si alloy targets in Ar/O₂ atmosphere, enabling the formation of amorphous alumina coatings with varying Si contents (see Fig. 1). To assess the phase evolution of these coatings, in-situ X-ray diffraction (XRD) was employed during vacuum annealing up to 1200 °C. To gain further insight into the role of Si in the phase stability and phase transformations of alumina at high temperatures, additional analytical techniques - including X-ray Photoelectron Spectroscopy (XPS), Scanning Auger-Meitner Electron Spectroscopy (AMES), and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) - were employed to study the films prior to and after annealing at 1200 °C. In this contribution the results are summarized, and a detailed analysis of the structural and chemical characteristics of the thin films is presented

The Lₚ-Brunn–Minkowski inequalities for variational functionals with 0 ≤ p < 1

The infinitesimal forms of the Lₚ-Brunn–Minkowski inequalities for variational functionals, such as the q-capacity, the torsional rigidity, and the first eigenvalue of the Laplace operator, are investigated for p≥0. These formulations yield Poincaré-type inequalities related to these functionals. As an application, the Lₚ-Brunn–Minkowski inequalities for torsional rigidity with 0≤p<1 are confirmed for small smooth perturbations of the unit ball

Symbolic execution for refuting ∀∃ hyperproperties

Many important hyperliveness properties, such as refinement and generalized non-interference, fall into the class of ∀∃ hyperproperties, and require, for each execution trace of a system, the existence of another execution trace relating to the first one in a certain way. The alternation of quantifiers in the specification renders these hyperproperties extremely difficult to verify, or even just to test. Indeed, contrary to trace properties, where it suffices to find a single counterexample trace, refuting a ∀∃ hyperproperty requires not only to find a trace, but also a proof that no second trace exists that satisfies the specified relation with the first trace. As a consequence, automated testing of ∀∃ hyperproperties falls out of the scope of existing automated testing tools. In this paper, we present a fully automated approach to detect violations of ∀∃ hyperproperties in synchronous and asynchronous infinite-state systems. Our approach extends bug-finding techniques based on symbolic execution with support for trace quantification. We provide a prototype implementation of our approach, and demonstrate its effectiveness on a set of challenging examples

Finite element modal analysis of moving bandsaw blades using incremental rod theory with consideration of the pre-stress distribution in the cross section

Machining operations are susceptible to different kinds of adverse dynamic phenomena. This is especially true for the band sawing process with its slender endless-moving blade that may exhibit forced oscillations, self-excited vibrations, or even torsional flexural buckling under high load magnitudes. Current research primarily focuses on the cutting of metal slabs and is motivated by the need to improve the surface quality of the cut, to increase productiv- ity, to minimize scrap, and to reduce tool wear. In the present study, a mechanical model that accurately captures the dynamics of the moving blade under different working conditions is developed and verified by comparison against physical experiments. The bandsaw blade is modelled as an unshearable Kirchhoff rod with a thin rectangular cross-section. Linear modal and buckling analyses are performed with the incremental rod theory of second order that accounts for axial pre-tension and pre-twisting of the blade. This pre-twist is imposed by the tilting angle between the linear blade guides and the wheels of the drive system. A large pre-twist occurs when the wheel axes are deliberately not in parallel to the plane of the cut surface as is typical for horizontal bandsawing. Due to the Wagner effect, pre-tensioning and pre-twisting alter the effective torsional behaviour owing to the non-trivial uniaxial stress distribution over the width of the rectangular blade cross-section. The torsional rigidity of the rod must be modified accordingly. Forces in the cut are approximated by prescribed distributed loadings allowing for an estimation of how the load affects the modal spectrum of the blade; both follower and dead loadings are considered. The model may be extended in the future with respect to the tool-workpiece interaction in order to capture self-excited vibrations due to regenerative chatter. A non-material finite element model is implemented to compute actual numerical solutions and perform parameter studies. Numerical results are further compared with experimental measurement data for certain parameter configurations to empirically justify the simulation model

Programmable few-atom Bragg scattering and ground-state cooling in a cavity

By integrating tweezer arrays with a high-cooperativity ring cavity with chiral atom-cavity cou- pling, we demonstrate highly directional Bragg scattering from a programmable number of atoms. Through accurate control of the interatomic distance, we observe a narrowing-down of the Bragg peak as we increase the atom number one by one. The observed high-contrast Bragg interference is enabled by cavity sideband cooling of both the radial and axial motions to near the ground state with phonon occupation numbers below 0.17 and 3.4, respectively. This new platform that integrates strong and controlled atom-light coupling into atomic arrays enables applications from programmable quantum optics to quantum metrology and computation