Swiss contribution to the IEA HPT Annex 58 HTHP Most industrial process heat is still produced from fossil fuels, but achieving Switzerland’s Energy Strategy 2050 (ES2050) climate goals requires a transition to renewable energy sources. Hightemperature heat pumps (HTHPs), which operate at temperatures above 100 °C, offer an efficient pathway for electrification, particularly for low- and medium-temperature process heat demands. However, adoption has been slow due to economic, technological, integration, and knowledge barriers. The HTHP-CH project addressed these challenges by developing practical guidelines, evaluation tools, and a web-based integration platform to support optimal HTHP implementation in Swiss industry. These solutions were validated through case studies (ELSA Estavayer Lait SA, Cremo SA, Gustav Spiess AG) in processes such as drying, evaporation, and cleaning-in-place (CIP), effectively bridging the gap between theory and practice. The project also contributed to the international IEA HPT Annex 58 project. Through these case studies, the project developed an evaluation tool and produced guidelines to facilitate the practical adoption of synergies relevant to the Swiss industry. Results were disseminated widely via webinars, publications, workshops, and international collaboration with 13 partner countries in the IEA HPT Annex 58. The Swiss project team, comprising OST-IES, EPFL-IPESE, HEIG-VD/IGT, and CSD Engineers, focused on optimizing HTHP integration through industrial case studies, modelling, and practical guidelines. The project evaluated energy efficiency gains, CO₂ reduction potential, and economic feasibility. Close collaboration with Swiss industrial partners ensured the practical applicability of the approach, while national projects provided additional insights into local HTHP integration strategies. A Swiss Market Report was produced, outlining the status of HTHPs in Switzerland, including ongoing research and development, market potential, realized examples, and available funding programs. The report also summarized available HTHP technologies and demonstration cases, highlighting end-user applications in various sectors, including food and beverage, wastewater treatment, electronics, chemicals, pulp and paper, ceramics, biorefinery, and pharmaceuticals. Each case study was presented with visualizations of HTHP integration concepts and technical data. This final Summary Report summarizes the main outcomes of the HTHP-CH project and references several Appendix documents that provide comprehensive insights and additional resources to enhance understanding and application of the guidelines. A compilation of dissemination materials like webinar presentations, workshop results, journal and conference papers, as well as lessons learned from case studies, offers valuable perspectives and facilitates knowledge transfer. Finally, an outlook on possible next steps is provided, outlining potential future areas for further development of HTHP technology and products.

Fault damage zones consists of intricate networks of microcracks and subsidiary faults surrounding a primary fault core, which are highly sensitive to changes in stress conditions [1]. These zones are particularly susceptible to activation due to fluid injection into the main fault, a common practice in geothermal energy extraction and other sub-surface engineering applications. Once fluid is injected, elevated pore pressure reduces the effective normal stress, lowering frictional resistance and promoting the nucleation and propagation of microcracks. These microcracks weaken the rock matrix and can coa- lesce into larger fractures, reducing fault stability. The slip of individual microcracks can induce a chain reaction, triggering further slips in adjacent fractures—a process known as cascading rupture. This phenomenon can propagate through the fault damage zone, potentially leading to significant dynamic or seismic events [2]. Therefore, understanding these processes is crucial for assessing and mitigating the seismic risks associated with hydraulic stimulation and optimizing its effectiveness in enhancing reservoir permeability.

In this study, we simulate these aseismic cascade slip events within fault damage zones induced by fluid injection by constructing a 2D discrete fracture network (DFN) model across a primary fault. We leverage a fully coupled hydro-mechanical solver (PyFracX) developed at the Geo-energy Lab of EPFL, based on the boundary element method (BEM) for our simulations. By injecting fluid at a constant pressure into the main fault, we aim to elucidate how fluid pressure diffusion and stress perturbations can initiate a sequence of aseismic slip events in the damage zone. The DFN model allows us to capture the complex interactions between microcracks and to analyze how pressure changes propagate through the network. By simulating various injection scenarios, we can identify critical parameters that govern activation. The orientation relative to the initial stress state and percolation number of the DFN, along with the initial distance to failure (residual shear strength) and fluid overpressure, play crucial roles in the propagation of these cascade aseismic slip events. This study will contribute to the broader understanding of induced seismicity and provide valuable insights for mitigating the risks associated with fluid injection in geothermal and other subsurface projects. Ultimately, our findings will help develop more effective strategies for managing induced seismicity and improving the safety and efficiency of geothermal energy extraction.

References [1] D.R. Faulkner et al. “A review of recent developments concerning the structure, mechanics and fluid flow properties of fault zones”. In: Journal of Structural Geology 32.11 (2010). Fault Zones, pp. 1557–1575. issn: 0191-8141. doi: https://doi.org/10.1016/j.jsg.2010.06.009. url: https://www.sciencedirect.com/science/ article/pii/S019181411000101X. [2] Kadek Hendrawan Palgunadi et al. “Rupture dynamics of cascading earthquakes in a multiscale fracture network”. In: Journal of Geophysical Research: Solid Earth 129.3 (2024), e2023JB027578.

Re-activation of pre-existing discontinuities in the form of fractures and faults can occur due to fluid pressurization at depth. The increase of fluid pressure can facilitate the propagation of slow frictional ruptures over considerable distances and can also trigger frictional instabilities. These can occur in response to either anthropogenic fluid injection (e.g. hydraulic stimulation) or via natural occurences (e.g. serpentine dehydration). Hydraulic stimulation, a commonly employed technique in various geo-energy applications, aims to enhance the permeability of rock formations by creating new fractures or reactivating the pre-existing ones with pressurised fluid injection. This process induces slip along existing fractures, resulting in a range of behaviors from stable, slow-slip events to more rapid, dynamic ruptures.

Recent studies have made significant strides in quantifying the mechanics of fluid-induced frictional slip in single-plane systems. For instance, S´aez and Lecampion (2024) [2] identified four distinct slip regimes for a fluid-induced slip-weakening fault in 3D, progressing from quasi-static slip to nucleation, arrest, and ultimately a runaway dynamic rupture based on three dimensionless numbers that consist information on the in-situ stress state, injection strength and peak and residual friction coefficients. These findings provide a clear understanding of how single-plane fractures respond to fluid pressure. However, the response of interconnected fracture networks, which is more representative of real-world subsurface conditions, to fluid injection remains poorly understood. The intricate stress interactions that arise between multiple fractures under fluid pressure introduce an additional level of complexity that existing theoretical and numerical models have yet to fully capture. Although some numerical studies have qualitatively explored the behavior of fracture networks subjected to fluid injection, detailed quantification of energy distribution and slip mechanics within these interconnected systems have not been investigated in detail [1].

In this study, we derive an energy balance of the hydro-mechanical system consisting of the fractured rock mass and the injected fluid. Our primary goal is to understand the overall energy budget, and notably quantify the partitioning of the energy dissipated in plastic slip along major and the surrounding minor fractures. Specifically, we evaluate whether the presence of additional smaller fractures leads to a shielding effect on major fractures—where stress interactions inhibit rupture propagation—or a promoting effect, where interactions facilitate rupture growth and energy transfer, as a function of in-situ stress, statistical and material properties of the discrete fracture networks, as well as injection conditions.

References [1] Federico Ciardo and Brice Lecampion. “Injection-induced aseismic slip in tight fractured rocks”. In: Rock Mechanics and Rock Engineering 56.10 (2023), pp. 7027–7048. [2] Alexis S´aez and Brice Lecampion. “Fluid-driven slow slip and earthquake nucleation on a slip-weakening circular fault”. In: Journal of the Mechanics and Physics of Solids 183 (2024), p. 105506.

BACKGROUND Despite multiple clinical trials in young patients with newly diagnosed high grade gliomas (HGG), survival remains poor. PNOC008 is a single-arm, multi-center pilot trial, investigating the feasibility, toxicity, and efficacy of a molecularly guided individualized treatment approach following radiotherapy. METHODS Patients aged ≤21 years with newly diagnosed, localized, hemispheric HGG (Stratum A) or non DIPG, diffuse midline glioma (DMG) (Stratum B) were eligible. Comprehensive molecular profiling (targeted gene panel, whole exome, and whole transcriptome sequencing) was performed on primary tumor tissue. The molecular data was reviewed by a dedicated tumor board that recommended an individualized treatment plan combining up to four FDA approved drugs. Patients were followed for toxicity and efficacy. Circulating tumor DNA (ctDNA), imaging, and quality of life (QOL) measures were collected at multiple timepoints. RESULTS Fifty-five HGG patients enrolled between 2018 and 2023 (median age 11 years [range 2-20], n=31 female, n=29 Stratum A), including H3K27-altered (n=17), H3/IDH-wildtype diffuse pediatric-type (n=16), and H3G34-mutant diffuse hemispheric glioma (n=12). In 44 patients that followed the recommended treatment, median overall survival (OS) from time of study enrollment was 26.5 months in Stratum A (lower 95% CI: 18.5) and 23.6 months in Stratum B (lower 95% CI: 16.8), and 30 months in H3G34-mutant patients (n=10, lower 95% CI:24.6) with median follow-up of 34.5 months for all patients (lower 95% CI: 32.2). The treatment recommendations most commonly included alkylator with targeted therapy combinations. The often novel drug combinations were generally well tolerated with grade 3 or 4 treatment-related adverse events being mostly hematologic. Central imaging, ctDNA, and QOL analyses are underway. CONCLUSIONS A personalized treatment approach using comprehensive transcriptomic and genomic analysis is feasible and well tolerated with encouraging survival data in children and young adults with HGG. Further analyses of molecular subgroups and correlatives are ongoing.

Prostate cancer is one of the most heritable cancers. Hundreds of germline polymorphisms have been linked to prostate cancer diagnosis and prognosis. Polygenic risk scores can predict genetic risk of a prostate cancer diagnosis. Although these scores inform the probability of developing a tumor, it remains unknown how germline risk influences the tumor molecular evolution. We cultivated a cohort of 1250 localized European-descent patients with germline and somatic DNA profiling. Men of European descent with higher genetic risk were diagnosed earlier and had less genomic instability and fewer driver genes mutated. Higher genetic risk was associated with better outcome. These data imply a polygenic “two-hit” model where germline risk reduces the number of somatic alterations required for tumorigenesis. These findings support further clinical studies of polygenic risk scores as inexpensive and minimally invasive adjuncts to standard risk stratification. Further studies are required to interrogate generalizability to more ancestrally and clinically diverse populations.

The continuous rise in atmospheric carbon dioxide (CO2) level poses a major environmental and technological challenge, driving the urgent need for scalable CO2 utilization strategies. This thesis explores functional molecules based on main group elements as a versatile platform for sustainable CO2 conversion and energy device stabilization. In chapter 1, the scientific motivation and current limitations of CO2 capture and utilization are discussed, with emphasis on catalytic valorization approaches such as the cycloaddition of CO2 to epoxides and hydrogenation to value-added products. The role of main-group element chemistry and Frustrated Lewis Pairs (FLPs) in overcoming the challenges associated with transition metal catalysts is introduced, alongside the potential of functional molecular additives in stabilizing next-generation photovoltaic devices such as perovskite solar cells (PSCs). In Chapter 2, a metal-free catalytic system comprising thermally activated silica gel and tetrabutylammonium iodide (TBAI) is developed for the cycloaddition of CO2 to epoxides. This catalyst enables the production of cyclic carbonates with high yields. A continuous-flow reactor was designed and optimized for industrial integration, operating efficiently under mild conditions and compatible with modeled industrial flue gas, with life cycle and economic assessments supporting its practical viability and sustainability. Chapter 3 introduces a Hammett parameter-guided strategy for designing triarylborane Lewis acids to enhance FLPs catalysis. By tuning electronic properties, a family of boranes with improved Lewis acidity was synthesized, achieving much higher turnover numbers for catalytic CO2 hydrogenation under metal-free conditions. Building on this, Chapter 4 reports the synthesis of a covalent triazine framework (B_CTF) embedding both triarylborane (Lewis acid) and triazine (Lewis base) units within a porous network. While the intrinsic FLPs activity of this B_CTF was limited by weak basicity, post-functionalization with an iridium complex restored catalytic activity, providing a proof-of-concept for heterogeneous FLP platforms. Chapter 5 expands the application of boron-based molecules beyond catalysis into energy materials. Functional triarylboranes and boronic acids were applied as additives in perovskite PSCs, either as passivating interfacial layers or precursor additives. These boron compounds stabilized the formamidinium cation and led to improvements in both device efficiency and long-term thermal stability. In summary, this work advances functional molecule design for CO2 valorization and energy technologies, offering scalable, metal-free approaches for tackling key challenges in the transition to a low-carbon future.

This thesis explores the application of artificial intelligence methods in digital health, clearly demonstrating the pathway from technological breakthroughs to practical health solutions in four critical areas: plant disease detection, food recognition, personalized glycemic response forecasting, and musculoskeletal modeling. Leveraging deep learning and reinforcement learning techniques, this work highlights the feasibility of practical, scalable AI-driven solutions to longstanding healthcare challenges.

First, a deep convolutional neural network trained on an extensive dataset successfully identifies plant diseases from leaf images, presenting an effective approach to smartphone-assisted agricultural diagnostics. Next, advanced instance segmentation models enable accurate food segmentation and recognition from real-world images, facilitating improved dietary assessments essential for nutritional epidemiology. Subsequently, Temporal-Fusion-Transformers accurately forecast individualized postprandial glycemic responses using continuous glucose monitoring data and nutritional information, highlighting personalized nutrition possibilities. Finally, deep reinforcement learning methods are utilized to synthesize physiologically accurate human movements within musculoskeletal simulations, demonstrating potential applications in biomechanics and rehabilitation.

The thesis further emphasizes the transformative potential of crowdsourced participatory research to accelerate AI innovations, reducing barriers to practical implementation and promoting rapid, tangible public health impacts.

We study the behaviour of electromagnetic waves in terms of their propagation through time and space.

First, while time typically flows in only one direction for complex systems, the reciprocal nature of most wave systems allows for a form of time reversal. Indeed, for a wave f(t, r), its time-reversed counterpart f(-t, r) can also physically exist. Moreover, methods have been developed to create this time-reversed wave, enabling the application of time reversal to wave focusing and imaging. In this context, we record the direct-time wavefront f(t, r) emitted by an unknown source on a (ideally closed) surface, known as a time-reversal mirror. This recording is then time reversed and played back from the mirror, causing the resulting wave to converge back to the original source location. If the original source is absent, the wave continues propagating, slightly blurring the focus and exhibiting the diffraction patterns observed in classical optics.

A wide range of methods has been developed to enable wave imaging and focusing beyond the diffraction limit, achieving "super-resolution." We begin with a review of the theory, methods, and applications of super-resolution imaging and focusing in the radio-frequency range. We then contribute to the theoretical framework of time-reversal by, first, proposing a new convergence metric based on a combination of probability theory and electromagnetic energy density, and second, generalising the theory of the time-reversal cavity for nonreciprocal media, high-order multipole sources, and proposing a link between the dispersion relation of homogeneous media and the attainable resolution. We subsequently present three applications of time-reversal imaging for electromagnetic compatibility pre-compliance testing aimed at imaging the current from an electrostatic discharge: i) using a resonant metalens, ii) leveraging cable radiation, and iii) with a low-cost setup.

In the second part of the thesis, we study the spatial behaviour of complex electromagnetic sources. This behaviour can be described analytically by the multipole expansion, a widely used method in wave systems. Traditionally, this method projects complex field distributions onto a basis of spherical harmonics. The strong connection between this method and Green's function warrants, first, an analysis of the singular behaviour of this function in uniaxial media. We then present the novel Cartesian time-domain multipole expansion, along with a practical recursive implementation. We illustrate the method on time-reversal imaging of intricate sources. Additionally, we apply this expansion to model the time-domain fields radiated by, first, impulse-radiating antennas, and second, lightning. Finally, we discover that the Cartesian approach is essential in anisotropic media to describe novel degrees of freedom in wave propagation.

Nickel-Titanium (NiTi) shape memory alloys (SMAs) have been broadly employed in medicine, watch, and automotive industries thanks to their remarkable mechanical properties mainly realized by reversible martensitic transformation. The theory named Phenomenological Theory of Martensite Crystallography (PTMC) is frequently applied to explain the experimental observations obtained by Transmission Electron Microscopy (TEM). Our current understanding of NiTi alloys is however still limited by: a) the characterization of martensite on mesoscale (1 nm - 100 um) which is the dimensional range where the crystallographic interplays with the mechanics by the formation of complex martensitic microstructures is missing, and b) PTMC is phenomenological and does not permit to understand the transformation mechanisms. Therefore, it is significant to revisit the NiTi and other shape memory alloys with new characterization methods such as electron backscatter diffraction (EBSD) and Transmission Kikuchi Diffraction (TKD) techniques and compare the results with the PTMC and another alternative theory called Correspondence Theory. Two types of NiTi alloys will be studied: a martensitic NiTi (with shape memory properties) and an austenitic NiTi (with superelastic properties). The microstructure evolution of the NiTi alloys under deformation will be investigated by EBSD and TKD. The aim of this PhD thesis is to understand the reorientation of the martensitic variants, the twinning modes in martensite, and the texture evolutions in martensitic NiTi, and the martensitic transformation, variant selection and deformation twinning in superelastic NiTi. The interaction work (IW) associated with habit plane variants (from PTMC) or with individual variants (from Correspondence Theory) will be used to predict the variant reorientation or variant selection. A systematic comparison between the two theories will be made. A clear understanding of these events will help us to further explore the nature of the martensitic transformation of NiTi alloys, and promotes their applications by improving the predictions of the microstructure evolution and mechanical properties.