The lack of fundamental knowledge of the interaction between an acoustic wave and a turbulent boundary layer grazing an acoustically treated surface, such as an acoustic liner, is the cause of unexpected and unphysical results found when performing the acoustic characterization of the sound absorbing surface with inverse eduction methods. This is because, in this field, acoustic and aerodynamic have never been fully coupled. To fill this knowledge gap, the acoustic and hydrodynamic velocities near an acoustically treated surface must be measured. Since it cannot be done only with state-of-the-art experiments, because of hardware and field-of-view limitations, I propose to complement experiments with scale-resolved high-fidelity numerical simulations based on the lattice-Boltzmann very-large-eddy simulation method. Numerical results will be used to explain the physics of the acoustic-flow interaction. Advanced data analysis methodologies will be developed and applied to separate the acoustic-induced velocity near the wall from the hydrodynamic one. At the same time, the numerical database will be used to compare inverse methods, employed to acoustically characterize the sound absorbing surfaces, in order to explain the physical reasons behind the unexpected results, and propose physics-based corrections. Furthermore, by describing the flow-acoustic interaction, it will be possible to model and predict the drag increase caused by the coupling between the acoustic-induced velocity and the free-stream one. My description of the flow-acoustic interaction will solve the scientific debate about the unexpected results and pave the way towards future broadband low-noise low-drag acoustic meta-surfaces to increase propulsion efficiency and reduce noise of future, more sustainable, aircraft engines.

We intend to set up a new globalized perspective to tackle water and food security in the 21st century. This issue is intrinsically global as the international trade of massive amounts of food makes societies less reliant on locally available water, and entails large-scale transfers of virtual water (defined as the water needed to produce a given amount of a food commodity). The network of virtual water trade connects a large portion of the global population, with 2800 km3 of virtual water moved around the globe in a year. We provide here definitive indications on the effects of the globalization of (virtual) water on the vulnerability to a water crisis of the global water system. More specifically, we formulate the following research hypotheses: 1) The globalization of (virtual) water resources is a short-term solution to malnourishment, famine, and conflicts, but it also has relevant negative implications for human societies. 2) The virtual water dynamics provide the suitable framework in order to quantitatively relate water-crises occurrence to environmental and socio-economic factors. 3) The risk of catastrophic, global-scale, water crises will increase in the next decades. To test these hypotheses, we will capitalize on the tremendous amount of information embedded in nearly 50 years of available food and virtual water trade data. We will adopt an innovative research approach based on the use of: advanced statistical tools for data verification and uncertainty modeling; methods borrowed from the complex network theory, aimed at analyzing the propagation of failures through the network; multivariate nonlinear analyses, to reproduce the dependence of virtual water on time and on external drivers; multi-state stochastic modeling, to study the effect on the global water system of random fluctuations of the external drivers; and scenario analysis, to predict the future probability of occurrence of water crises.

Pressuriz3D aims to advance in the field of pressurized protonic ceramic electrolysis cells (PCEC) with the utilization of advanced fabrication techniques such as masked-stereolithography (MSLA) and robocasting. Aiming to reduce the utilization of fossil fuels on a global scale, the design of systems for hydrogen production via steam electrolysis is fundamental to increase the reliability of renewable energy sources. PCECs are high-temperature electrolysers which use ceramic electrolytes characterized by high protonic conductivity. Compared with other HTEs (e.g., solid oxide electrolysis cells, SOEC), this type of conduction mechanism can significantly reduce the operating temperature of the device (e.g., from 700-900 °C to 300-650 °C respectively for SOEC and PCEC). Additionally, PCECs can produce directly pure hydrogen eliminating the purification process to remove steam necessary for SOECs. Fabrication of a PCEC via additive manufacturing (AM) techniques can significantly reduce production costs and the waste of material during processing, thus boosting sustainability and circularity aspects. complex-shaped electrolyte can be produced increasing the mechanical resistance with the joining materials to maintain the gas tightness of the system (i.e., glass-ceramic sealants). Patterned surfaces coupled with glass ceramic sealants will allow the utilization of pressurized gases, which are expected to significantly increase PCEC performances. Furthermore, geometry modification of the electrolyte membranes, thanks to the fabrication via MSLA printing, can further improve the performance and the hydrogen production rate. A high impact on the future career of the candidate is expected by complementing his current background with new skills in the field of hydrogen conversion, in particular, the design and processing of PCEC and the integration of glass-ceramic sealants for the fabrication of pressurized systems.