This study demonstrates the feasibility of acoustic backscatter com- munication in complex metal structures, extending previous work that focused on simple, isolated metal specimens. Real-world mea- surements examine one-way channel gains and backscatter signal strengths across various structural elements, including weld and screw connections. Results demonstrate successful communication over a 3-element, 13-meter channel with significant attenuation.

The complete thermo-chemical conversion of solid biogenic fuels (e.g., wood chips, wood pellets) is associated with unavoidable release of (inorganic) particulate matter (PM) emissions; this is especially a challenge in small-scale combustion appliances. In this context, the utilization of so-called additives is a promising, fuel-oriented PM mitigation measure. During combustion, suitable additives lead to a temperature-stable integration of the main PM-forming elements (e.g., potassium) from the biomass in the bottom ash.

Magnetic Resonance Imaging (MRI) is a powerful tool that provides deep insights into the human body by determining the distribution of various components and visualizing dynamic processes such as cardiac blood flow. Similarly, in the field of process engineering, understanding flow parameters and component distribution is critical, particularly in the study of stirred tank reactors (STRs). Traditional medical MRI scanners, which are typically designed for horizontal orientation, present certain limitations for investigating STRs. The non-intrusive nature of MRI, combined with its ability to analyse opaque and complex mixtures offers detailed, three-dimensional insights into STRs. These insights help tackling the significant challenge of understanding the complex hydrodynamics of STRs, thus fasten optimization and ease scale-up efforts [1]. In this study we use MRI to investigate liquid flow in an STR model of an inner diameter of 188 mm and a height of 1000 mm. All measurements were performed on a vertical 3T MRI system, optimized for process imaging. The open radiofrequency shielding design and the vertical orientation of the MRI system, allow to accurately control the stirrer speed with an electric motor. Different impeller types and rotational speeds and their effects on the fluid hydrodynamics are studied. In the future we are planning to investigate realistic industrial conditions and complex multi-phase material systems. We anticipate these measurements to enhance our understanding of the complex hydrodynamics within STRs. Moreover, the measurements can be used to test and improve the accuracy of computational fluid dynamics (CFD) models for process design and optimization. References: [1] Stitt, H., Chemical Engineering Journal (2002), 47-60

Effective mixing is fundamental to optimizing process performance in the chemical and biochemical industries. The mixing efficiency is predominantly governed by the fluid flow within these systems [1]. Understanding such mixing processes significantly benefits from precise velocity measurements and high-resolution imaging techniques. Nonetheless, obtaining detailed three-dimensional insights into their mixing states continues to present a substantial challenge. Magnetic Resonance Imaging (MRI) is one of the most versatile among the various tomographic techniques suitable for process engineering applications. It leverages the nuclear magnetic resonance (NMR) phenomenon [2,3] to measure flow, diffusion, chemical composition, and temperature with high spatial and temporal resolution. Recent advancements have expanded its use in process engineering [4,5], enabling investigations into phase distributions, microreactor flows, and packed bed dynamics. To improve the signal-to-noise ratio (SNR) and temporal resolution of MRI systems, multiple receiver coils can be placed around the object to acquire the signal in parallel. Since MRI has been primarily applied in medical domain, the existing coil arrays are developed for human anatomies. In this work, we build custom coil arrays tailored to chemical reactors and investigate the impact of receiver coil density on MRI-based velocity measurements using the world’s largest vertical 3 Tesla MRI scanner. We compare 5-channel and 15-channel receive arrays to evaluate their performance in capturing flow behavior within structured packings with Schwarz-Diamond-Triply Periodic Surface (TPSf) designs, relevant to chemical engineering. Initial velocity measurements in water phantoms reveal that the 15-channel array significantly improves spatial resolution and SNR over the 5-channel configuration. These enhancements enable detailed mapping of velocity fields, finer resolution of flow dynamics, and improved visualization of mixing and bubble interactions within complex geometries. References [1] Weiland, C., Steuwe, E., Fitschen, J., Hoffmann, M., Schlüter, M., Padberg-Gehle, K., & von Kameke, A. Computational study of three-dimensional Lagrangian transport and mixing in a stirred tank reactor. Chemical engineering journal advances. 2023, 14. Jg., S. 100448 https://doi.org/10.1016/j.ceja.2023.100448 [2] Rabi, I. I.; Zacharias, J. R.; Millman, S.; Kusch, P. A New Method of Measuring Nuclear Magnetic Moment. Phys. Rev. 1938, 53 (4), 318–318. https://doi.org/10.1103/PhysRev.53.318. [3] Bloch, F. Nuclear Induction. Phys. Rev. 1946, 70 (7–8), 460–474. https://doi.org/10.1103/PhysRev.70.460. [4] Benders, S.; Blümich, B. Applications of Magnetic Resonance Imaging in Chemical Engineering. Phys. Sci. Rev. 2019, 4 (10). https://doi.org/10.1515/psr-2018-0177. [5] Gladden, L. F.; Sederman, A. J. Recent Advances in Flow MRI. J. Magn. Reson. 2013, 229, 2–11. https://doi.org/10.1016/j.jmr.2012.11.022.

Stimuli-responsive lyogels are known for their capability to undergo substantial macroscopic changes upon exposure to external stimuli such as temperature, pH variations, or changes in solvent composition. These smart materials offer unique properties, showing potential applications in various fields, including actuation processes and flow control in the form of valves or catalyst carriers. This versatility makes them well-suited for integration into the design of advanced SMART reactors. However, achieving an effective integration requires a detailed understanding of lyogels' pore structure and diffusion behavior under various stimuli, as these factors fundamentally influence their functional properties. While several techniques can provide information about the macroscopic effects of lyogels during swelling/shrinking in response to different stimuli, only a few techniques can provide microstructural information about the swelling state. Nuclear Magnetic Resonance (NMR) is a suitable tool for the study of solvent dynamics inside macro, meso, and nanopores, through changes in their relaxation times and self-diffusion coefficient. Although 1H NMR relaxometry has been widely used to investigate the insitu swelling behavior of hydrogels, microgels, and different polymer matrices, there is still limited research on the dynamic swelling/shrinking behavior of lyogels in pure and/or mixtures of solvents of varying polarity. In our study, we use 1H NMR relaxometry and diffusion measurement to investigate the microstructural changes of lyogels in different solvent polarity at equilibrium state and during the solvent exchange process.

The climate change and the shortage of petroleum resources are two critical global issues that have led to an increased focus on sustainability, circular economy, and the use of renewable resources. Bioplastics, such as poly(lactic acid/lactide) (PLA), which are derived from agricultural resources, have emerged as a potential carbon neutral solution to these challenges. Moreover, one promising approach is the chemical recycling of PLA, closing the loop of its circular economy by using PLA-wastes as a feedstock for new and high-quality plastic products. Within the framework of this Call-for-Transfer project the potential of chemical recycling of PLA and its scale-up were investigated.

In climate and oceanographic research, precise temperature measurements within the very limited temperature range of the ocean are essential. This paper covers the design and analysis of a temperature sensor that measures with millikelvin accuracy. The first prototype has an energy consumption of 84.64 mWs with a sampling time of 10 seconds per measurement and a component cost of less than 100 EUR. The proposed design is able to measure within 6 mK accuracy on a subset measurement range despite a simple three-point calibration. The core circuit is enhanced with two temperature sensing elements to allow for an increase in sensor sensitivity. A further approach on sensor readout is proposed and analyzed, showing good potential in combination with linearized temperature compensation for the major part of this sensors range.

Werden technische Normen in beruflichen Lehr- und Lernprozessen thematisiert, so wird in der Regel nur formal auf sie verwiesen, oftmals in der Funktion von Autoritätsbeweisen. Tatsächlich lässt sich so eine lernhaltige Auseinandersetzung kaum angestoßen. Didaktisch und methodisch sind sie für berufliches Lernen bis heute kaum erschlossen. Bei genauerem Hinsehen bieten technische Normen und Richtlinien jedoch nicht nur inhaltlichen, sondern auch methodische Lernpotentiale. Daher wird in diesem Beitrag dargestellt, inwieweit technische Normen nicht nur als Inhalt, sondern auch als Struktur- und Entscheidungshilfe für Verfahren beruflichen Lernens und Lehrens genutzt werden können. Durch die Verbindung des „Prinzips der didaktischen Entsprechung“ (Ott, Reip & Isberner 1995, S. 204) mit bewährten Vorgehensweisen zur Ableitung einschlägiger Ausbildungs- und Unterrichtsverfahren soll so ein innovativer Beitrag zur berufsdidaktischen Forschung geleistet werden.

The understanding of streets strongly depends on what is considered a "typical street". Street concepts can contain different ideas and have the potential to expand our understanding of streets, but also to integrate new functions into street spaces. These can help to deal with the challenges posed by climate change, pandemics or simply the lack of open spaces for recreation or physical activity in residential areas. An important prerequisite is to change the current division of street space for different uses, which is a frequent cause of conflict. Most of these are related to the car and its increased need for space in the form of lanes and parking spaces, which blocks the integration of other forms of mobility and street uses. There are frequent calls for a fair distribution of road space (Nello-Deakin 2019), which cannot be defined absolutely and unambiguously due to the very different functions, characteristics and space requirements of the individual uses and the different possible approaches to this issue (Creutzig et al. 2020). Nevertheless, reducing the amount of space required by private vehicle traffic is a basic prerequisite for opening up development areas and redesigning streetscapes. With regard to existing roads that have the characteristics of liveable and climate-adapted roads, however, the question also arises as to how much these differ from roads with traffic prioritization in terms of space requirements, uses and climate-relevant design features and whether different redesign strategies are available for different types of roads in order to ensure their functionality in the future. On the basis of a literature review (Meyer 2024) on road concepts, their objectives and measures are highlighted and, with the help of public geodata, a pre-selection of road sections in the Hamburg context is made that can be characterized as climate-adapted and liveable in terms of their quantitatively measurable features. The selected road sections will be further examined for specific features and their character in terms of their affiliation to the corresponding road concepts by means of inspections, photo documentation and local design features. They are then contrasted with the street spaces focused on motorized private transport in order to work out the differences in terms of area and measures, which, based on different street types, enable explicit possibilities for improvement under different spatial-functional conditions. A proposal is made for the classification of the concept of fair road space distribution as a parameter for road space design in climate, mobility and social change, taking into account the respective space requirements for the case study of Hamburg. Finally, it is discussed whether and to what extent a modular system with individual building blocks to be fulfilled for each application ("street DNA") could be a practicable alternative concept.

The increase in plastic production is expected to exacerbate plastic waste disposal in terrestrial ecosystems. Soil represents a large reservoir for plastic wastes. Once disposed into the soil, plastic wastes interact with soil particles and biota and affect chemical, physical, and biological processes in soil (Jannesarahmadi et al., 2023). Microplastics (MPs) with distinct thermal and radiative properties and filling characteristics can alter energy partitioning over the surface of drying porous media and thus subsurface thermal regimes. The present study aims to quantify impacts of MPs on latent heat loss and temperature dynamics in drying sandy media. We conducted a series of evaporation experiments on sand columns (height: 20 cm – diameter: 8 cm) with grain size ranging from 0.4 to 0.8 mm and density of 2.65 g/cm³. Two types of microplastics with different characteristics and concentrations were used: Polyethylene (PE) with 34 to 50 μm particles and density of 0.94 g/cm³ and Polyvinylchloride (PVC) with particles ranging from 80 to 200 μm and density of 1.4 g/cm³. Mass loss rates from sand samples with different concentrations of MPs (i.e., 0.5, 2, and 5%) were compared with drying rates of the sand column without MPs serving as a reference. An array of thermocouples continuously measured vertical temperature profile in drying sand columns subjected to different wind and radiative boundary conditions. Airflow was generated by an adjustable fan and shortwave radiation flux was mimicked using halogen lamps with different intensities. Our preliminary results show that the presence of MPs with different characteristics alter evaporative loss and vertical temperature profiles in drying sand samples with the surface accumulation of PE particles (with lower density relative to water) influencing the thermal and radiative properties at the surface of drying porous media. The study provides new insights into the impact of MPs on energy partitioning dynamics over drying terrestrial surfaces and subsurface thermal regimes that could potentially affect various hydrological and biological processes in soil.

Diverse microbial communities are fundamental to healthy and productive soils, accommodating essential ecosystem services including nutrient cycling, organic matter decomposition, land-atmosphere carbon exchange, water and climate regulation, and contaminant control. The immense taxonomic and functional diversity of soil microorganisms makes deciphering the intricate interactions between soil, its inhabitants, and the far-extending effects for life on earth a complex challenge. Advances in the analysis of eDNA, like metabarcoding to determine community composition from soil samples, enable large-scale assessments across manifold habitat conditions. Based on the LUCAS 2018 soil biodiversity datasets, we aim to (i) identify key drivers shaping soil microbial community composition, and (ii) quantify marginal changes in soil microbial abundance, richness, and diversity forced by soil properties, climatic, and anthropogenic pressures. To improve the understanding of interactions between external drivers and soil microbial communities, we employ machine learning algorithms, in particular generalized additive models for increased interpretability (Hassani et al., 2024), to investigate and identify the parameters influencing the observed soil microbial diversity and richness in the LUCAS datasets. Our modeling efforts will enable us to predict changes in soil biodiversity under the influence of anthropogenic pressures and projected climate scenarios. Such an analysis can further support decision-making in land management with potential policy implications on a pan-European scale.

Between 2013 and 2018, striking hydrological and morphological changes were observed in the Tidal Elbe, in particular an unusually strong increase in tidal range, turbidity and sedimentation rates. The latter led to increased maintenance dredging, which, however, represents a major economic and ecological burden. Reasons for the described changes are seen in morphological changes in the mouth of the estuary, persistently low headwater discharges and insufficiently adapted sediment management (Weilbeer et al. 2021). The numerical models currently used cannot adequately represent these developments. In particular, the complex behaviour of cohesive sediments in the heavily anthropogenically influenced river sections such as the port of Hamburg poses a major challenge. The joint project ELMOD is conducted to improve the predictive capability of numerical models and to improve the understanding of estuarine sediment transport in general. For this purpose, the changes observed in the Tidal Elbe in the period 2013-2018 are analysed by means of hindcast studies and the model approaches used are extended on the basis of natural measurements and laboratory investigations. The partners involved are the Federal Waterways Engineering and Research Institute (BAW, model application), the University of the Bundeswehr Munich (UniBW, development of model approaches) and the Hamburg University of Technology (TUHH, field measurements and laboratory investigations).

Machine-to-machine communication over wireless networks is increasingly adopted to improve service and maintenance processes at airports, ports, and manufacturing plants. This brings with it the challenge of how to bootstrap a secure communication channel between the machines involved. Building on the idea of secure device pairing we research novel schemes for key establishment that exploit the proximity of the machines, the physical presence of a human or robotic operator, and/or the physical characteristics of the process. This approach allows us to engineer for post-quantum resistance as well as resilience against multi-instance attacks. To meet current safety and security norms we also provide the methodology to formally capture and verify the corresponding requirements.

In contrast to the wealth of information on evaporation dynamics from placid water surfaces such as lakes and reservoirs, estimating water evaporation from turbulent surfaces of streams remains a challenge. Evidence suggests a considerable change in evaporation from flowing surfaces relative to placid surfaces with local modifiers such as chemical, physical and biological processes that alter the energy budget and water temperature. While the studies on evaporation from wavy surfaces of oceans offer valuable insights, significant differences in hydrodynamics and heat exchange processes distinguish evaporation in oceans from that in rivers. Here we experimentally investigate how water flow characteristics (velocity and turbulence) and atmospheric boundary conditions (wind and radiation) affect evaporation rates and temperature dynamics in a flume. A closed flume (7.6 m length, 0.31 m width, and 0.5 m depth) is used to impose different boundary conditions over a test section of the flume (length of 1.5 m) while other parts of the flume are covered to reduce evaporative losses. Our preliminary findings show significant enhancement in evaporation rates, reaching 2-5 times that of placid water surfaces, driven by increases in surface velocity and turbulence characteristics. Furthermore, we observe that radiative and aerodynamic factors contribute nonlinearly to evaporation enhancement and affect temperature distribution in the water body. The study offers novel insights into evaporation from wavy and turbulent flowing water surfaces for better prediction of evaporation from riverine networks across flow regimes and climatic conditions.

Conference poster summarising a comparison of fare accessibility in the metropolitan regions of Hamburg (hvv) and Helsinki (HSL)

Programmieren ist eine Fähigkeit, die in allen MINT-Bereichen immer wichtiger wird. Schleifen sind ein Grundbaustein des Programmierens und stellen Studierende immer wieder vor große Hürden. Mit verschiedenen Aufgaben haben wir die Vorstellungen der Studierenden von Schleifen abgefragt. In diesen Aufgaben mussten die Studierenden kleine Programme lesen, deren Ausgabe aufschreiben und in Worten beschreiben, was passiert, während die Programme ausgeführt werden. Die Programme enthielten einfache, unabhängig verschachtelte und abhängig verschachtelte Schleifen. Unsere Untersuchung wurde in zwei verschiedenen Vorlesungen mit unterschiedlichen Dozierenden und Programmiersprachen durchgeführt. Dabei wurde deutlich, dass viele Studierende die Reihenfolge der Ausführung einzelner Programmschritte nicht richtig erkannten, das Konzept der Verschachtelung nicht verstanden hatten oder Schwierigkeiten hatten, Programmstatements als innerhalb oder außerhalb einer Schleife stehend zu erkennen. Die gefundenen Schwierigkeiten und potentiell zugrundeliegende Fehlvorstellungen sollen in unserem eingereichten Poster präsentiert werden.

Sedimentation of fine grained sediments is a natural physical phenomenon influenced by bio-geochemical processes which occurs in rivers, channels and estuaries. The deepening of waterways in estuaries to enhance the navigability intensifies this effect. Even in the centre of the channel, where high flow velocities favour sediment transport and erosion, net sedimentation and accumulation occurs. Maintenance dredging is the main method to maintain the navigational channel which requires large financial investments and has potential negative impacts on the environment as well. The research project FAUST (For an improved understanding of estuarine sediment transport) addresses the challenge of net sedimentation and accumulation by investigating the transport properties of sediments in field (primarily in the Weser estuary) and in laboratory studies to advance the development of large scale 3D morphodynamic-numerical models. The conceptual design of the project FAUST has been presented in Patzke et al. (2019). Here we focus on erodibility experiments using a gust erosion microcosm system.

Small on-farm reservoirs play a vital role in sustaining irrigation and livestock water demands, particularly in regions facing acute water scarcity (Aminzadeh et al., 2024). However, comprehensive understanding of their global distribution and contribution to local water budgeting and management remains limited. This research leverages high-resolution satellite data from Sentinel 1 and Sentinel 2 to develop a global database of small agricultural reservoirs (<0.1 km2) across geographic and climatic zones. Machine learning algorithms are employed to improve the accuracy of reservoir detection from satellite imagery. In addition to mapping the spatial and temporal distribution of these reservoirs, we estimate their storage capacity by correlating surface area and depth metrics. The study enables monitoring of surface water storages across scales thus offering critical insights into the role of small reservoirs in water budgeting and accounting, particularly in water-stressed regions of the world.