Droplets and bubbles are omnipresent in many environmental and industrial applications that involve atomization and emulsification processes, and the ability to control the size of these dispersed elements in turbulent multiphase flows is essential for design and optimization purposes. Despite the importance of the fragmentation of one fluid in another one by turbulent eddies, a universal theory applicable to a majority of the scenarios is still missing. Following the seminal work of Hinze on characterizing the size of the largest stable droplets in turbulence known as Kolmogorov-Hinze theory, I aim to revisit this concept with a novel deterministic approach through theoretical investigation, experimental characterization, and numerical simulation. In my recent contribution, I have presented a novel description for the Hinze scale based on the concept of enstrophy transport across the scales in turbulence, which could serve as the basis for my deterministic approach to studying turbulent emulsification. By providing the theoretical basis for sustained homogenous isotropic turbulent flows, I will measure the spectral rate of enstrophy transport rates by the vortex stretching, surface tension, and other relevant mechanisms in a drop-laden turbulent flow in the lab using tomographic PIV and shape reconstruction. Furthermore, by performing direct numerical simulation (DNS), I will explore the situations where experimentation may be limited such as highly-dense emulsifications and surfactant-laden environments. The simulations will provide a large dataset based on which we could generate a universal theory for emulsification in turbulent drop-laden and bubbly flows. The FragTuRe project revisits the fundamental understanding of turbulent fragmentation by a concept that has not been employed before and aims at generating a novel case-independent universal correlation for the Hinze scale that is essential in many engineering applications.

Printed circuit boards are an indispensable technology present in all classes of modern electronics. Their flexible embodiments (flexPCBs) enable current and emerging form factors and drive the transition to human-centered applications. At the same time, PCBs are notoriously difficult to recycle and contribute majorly to the growth of electronic waste and an unsustainable use of resources. A paradigm change towards bioderived and biodegradable materials promises a remedy, however so far, no viable solution for sustainable (flex)PCBs exists. MycoSub takes on an entirely new approach of growing and refining fungal mycelium skins as environmentally friendly and entirely biodegradable, yet high performance substrate material for the manufacturing of flexPCBs. Building upon MycelioTronics, the first mycelium-based electronic circuits, we here aim at developing an industry-compatible process flow that seamlessly merges into established commercial procedures for rapid adoption of the technology. With facile post-processing steps that do not impede biodegradability, we will achieve a competitive flexible circuit board substrate with high thermal stability, high flexibility and low surface roughness. We aim to develop both conventional subtractive (etching) as well as fully sustainable additive manufacturing techniques for low-conductivity, soldering-compatible conducting traces. Such MycoSub-flexPCBs will ultimately provide unprecedented levels of sustainability through the combination of a biodegradable yet resilient substrate with efficient waste-minimizing, energy-saving workflows and re-use strategies for precious metals and electronic components. These endeavors will be accompanied by thorough material characterization, ensuring that MycoSub materials live up to the high requirements of the industry. Ultimately, MycoSub-flexPCB demoboards will showcase the potential of sustainable solutions for the broad ecosystem of flexible electronics.

Large-scale quantum experiments do not work in isolation. Substantial classical computing power is required to control the experiment and process the results. This necessarily creates information-transmission bottlenecks at the interface between quantum and classical realms. These bottlenecks create scalability issues that prevent us from using existing architectures to the best of their capabilities and may even impair our ability to further scale up system sizes. In this project, we adopt a unifying framework that takes into account all computing resources (quantum and classical). We develop quantum-to-classical converters to overcome information-transmission bottlenecks. Dubbed shadows, they leverage randomization, as well as quantum-enhanced readout strategies to obtain a succinct classical description of an underlying quantum system that can then be used to efficiently predict many features at once. The shadow paradigm is compatible with near-term quantum hardware and utilizes genuine quantum effects that do not have a classical counterpart. Building on these ideas, we also establish rigorous synergies between quantum experiments and classical machine learning. Shadow learning protocols use shadows to succinctly represent training data obtained from actual quantum experiments. A classical training stage then enables data-driven learning of genuine quantum phenomena. Finally, we develop new tools to ensure reliable execution on current quantum hardware, thus bridging the gap between theory and experiment. My interdisciplinary skill set combines methods from modern computer science with quantum information and has already led to numerous high-impact contributions (e.g. 1 Nature Physics with more than 350 citations and 2 Science publications). These insights form the basis for this larger project, where we lay the foundation for scalable and practical quantum data processing and learning that can keep up and grow with future improvements in quantum technology.

Half of the total electric energy consumed within the European Union is used for operating electric machines. Those might feature high efficiency for rated load, but partial load and overload performance often is very poor. Additionally, given some voltage and current limits for driving machines, designers need to trade good performance at high torque versus high-speed capabilities. Machines with speed-dependent characteristics would facilitate overcoming the current limitations and thus are the subject of this ERC project. The main approach for realizing operation dependent machine characteristics is to acquit oneself of thinking that the electric machine structure must be static. Allowing solid parts of the rotor to change in position or powder-based compounds to vary in local density while rotating enables a new class of designs. The realization requires all-new methods for designing the speed-dependent properties. This embraces techniques for co-simulating mechanical and electromagnetic aspects including components’ or particles’ movement, the experiment-driven characterization of powder-based soft magnetic materials with variable local density, micro- versus macroscopic modelling of magnetic properties, and the development of promising concepts for future electric machine design and their experimental proof of concept. The basic idea is simple, but its effective implementation is challenging and requires pioneering cross-disciplinary research. The PI has successfully demonstrated the ability to advance the state-of-the-art in electric machine design. The gained results will allow for simultaneously achieving higher net efficiency levels and reducing the consumption of resources due to an improved utilization of the applied components. The project will thus help to reduce the overall energy consumption and to minimize the need for critical raw materials. The reward of this project is tremendous and the expected outcome will beneficially affect our future lives.

This project focuses on the development of a new type of electrostatic actuators with high potential for the critical European sector of Space Technologies and the field of Smart Materials. Electrostatic actuators, in particular dielectric elastomers, have long been proposed for space applications. However, due to limited materials choice, reliability and intrinsic technological limitations, this method has not yet met expectations. The EMVAC project is proposing a new concept of electrostatic actuation. It exploits electrically induced deformations of multilayered dielectric structures consisting of polymer films separated by vacuum gaps. Such multilayer systems can enable actuation of space mechanisms or operate in vacuum research/industrial applications on Earth. Due to employing high vacuum as a critical dielectric layer, as opposed to bulk insulating materials, this technology can provide unmatched performance in power density, strain and actuation speeds at low materials and manufacturing costs. However, the vacuum-gap introduces complex electrical phenomena within the dielectric structure. This relates to the accumulation of electrical charges at the film interfaces, resulting in an alteration of the force output of the entire system. This work will study the complex charge dynamics that dictates the force response of such systems by integrating experimental investigations and physics-oriented theoretical approaches. A framework for materials selection will be proposed. Various polymer films will be investigated. Different actuators employing the polymer film/vacuum gap topology will be created and demonstrated in a high vacuum environment. The research fellow will deepen his expertise in the fundamentals of dielectric materials and electroactive polymers, while also acquiring critical soft skills in managing a multidisciplinary research project that integrates fundamental and applied methods.