Subsurface reactive processes play a key role in dictating the evolution of subsurface environments, their interaction with surface water bodies and the migration and remediation of transported contaminants. In particular reactive hot spots tend to concentrate in mixing fronts between fluids of different compositions, such as recently infiltrated/injected fluids and resident groundwater, which develop in a range of situations, including CO2 sequestration operations and geothermal systems, contaminant remediation operations, and reactive hyporheic zones beneath rivers. Our understanding of the development and temporal dynamics of these hotspots is currently hampered by the limited sampling offered by boreholes. Recent breakthroughs in geoelectrics may however profoundly change our vision of these phenomena by providing non-invasive techniques with high sensitivity to many geological processes. GeoElectricMixing will hence develop a novel approach to investigate the temporal dynamics of reactive mixing processes from Complex Impedance and Self Potential signals. The coupling of reactive mixing and geoelectrics will be quantified and upscaled by integrating charge transport and polarization phenomena in a new modeling framework, recently developed by the host to predict the spatial distribution of chemical species and reaction rates across mixing fronts (WP1). Dedicated experiments will then be designed by integrating electrodes in a novel millifluidic setup to monitor jointly the temporal evolution of geoelectrical parameters and the spatial distribution of concentrations and reactions rate in a reactive mixing front progressing through the cell (WP2). GeoElectricMixing is thus expected to open a new window on subsurface reactive mixing phenomena, expanding our capacities to detect and quantify these processes in situ, and thus providing critical data to unlock current open questions on the dynamics of mixing processes and their role in reaction enhancement.

How can single-molecules be best utilized in electronics? Feature sizes of integrated circuits will reach this scale in 10-20 years (Moore’s Law). Typical molecular studies involve surface self-assembled components first synthesised elsewhere (ex situ). Yet surface-based (in situ) preparations offer several distinct synthetic advantages – also simplifying the construction of otherwise difficult to prepare asymmetrical surface-bound motifs. In this project I will (i) explore unconventional in situ syntheses of single-molecule electronic components, and (ii) develop scanning tunnelling microscopy (STM) techniques to assess the success of chemical reactions at the single-molecule scale. High yielding and versatile (e.g. ‘Click’ ) reactions will prove invaluable in this context. My largely unexplored approach will be used to rapidly screen novel single-molecule diodes and wires, improving rectification ratios and conductance. It will also be applied to produce complex molecular ‘test-beds’, allowing electron transport to be probed through single-molecules orientated parallel to the surface (enabling studies of mechanically weak analytes). This research has broad application and far-reaching impact in data storage and computation (‘wiring-up’ molecules in circuits), and will open up exciting possibilities in sensing and catalysis. Project results, and nano-science in general, will be actively promoted through a series of Outreach workshops, lectures (implemented in Europe) and a new internet blog, ‘Nanotechnology, Translated’ (contributing to the growing international science blogosphere). A planned secondment to the microelectronics industry will provide commercial and technical insights useful for securing funding and developing future technologies over the next two decades. The new collaborations and enhanced international profile, networks and training provided by this Fellowship will ultimately prove pivotal in helping me establish my independent academic career.

Geothermal represents a promising energy source to satisfy the growing energy needs with only minimal environmental impacts. To develop and test new technologies for energy production and storage in geothermal reservoirs, deep understanding of heat transport in fractured media is critically needed. The THERM project focuses on the investigation of heat transport and associated thermo-hydro-mechanical (THM) processes occurring during the lifetime of a geothermal reservoir. Fractured reservoirs, such as those found in enhanced geothermal systems, are characterized by a strong hydraulic and transport complexity coming from the fractures’ surface roughness, from their arrangement in networks, and from the interaction of the fractures with the surrounding rocks. As a result, the characteristics of the hydro-thermal flow which occurs when a cold fluid is injected into a hot fractured rock mass are controlled by fracture network discontinuities and properties of fracture surfaces themselves. While progresses have been made in characterizing and modeling subsurface heterogeneity in flow and solute transport processes, the effects of multi-scale subsurface heterogeneities on heat transport remains an open question. I propose new 3D fully coupled physical-based numerical models at different scales associated to state-of-the-art field experiments to develop a quantitative understanding of complex coupled processes occurring along fluid-rock interfaces during fluid circulation in geothermal systems. The main objectives are (i) to characterize the combined effect of fracture-scale and network-scale heterogeneity on flow and heat transport phenomena, and (ii) to design new field experiment to jointly measure the integrated THM behavior of fractures. Thanks to THERM, the ER will receive a unique multidisciplinary scientific training by Rennes 1 University that will reinforce significantly her expertise for future research activities and open new perspectives for career.

Low temperature thermochronometry (LTT) dating is a powerful tool in geoscience, used worldwide, to provide unique information on the thermal history of rocks. Using these insights geologists can achieve a better understanding of geological processes that have occurred over million year timescales even in settings where erosion has removed much of the geological record. Despite the success of these techniques in tackling geological problems, there still exists a major gap in our knowledge over the fundamental principles that underlie these dating systems. Much of this uncertainty stems from an incomplete understanding of inter and intra-crystal compositional variation and the influence this has on the kinetics of the dating system. Reaching a complete understanding of crustal thermal histories also remains a major challenge as the lowest temperature thermochronometers, apatite fission track (AFT) and apatite (U-Th)/He (AHe), are only sensitive over a temperature range of c. 120 – 40°C. The lower temperature limit of this range is also dependant on apatites having low degrees of radiation damage that can enhance retention of He within apatite. This project will advance AFT and AHe methodology by focusing on apatites enriched in U and Th from geological settings considered stable. The first goal is to obtain detailed REE compositional analysis using LA-ICP-MS to refine fission track annealing models and obtain high precision measurements of parent elements to improve AFT age data. The second goal is to ensure that the maximum amount of thermal history information is extract from the 4He concentration profile in the apatite crystal. This will be achieved by a combination of 4He/3He analysis and multi-single-grain AHe analysis of broken apatite crystals. By achieving these two goals the project will advance methodology, establish analytical capabilities at the host organisation and provide new insights into the thermal history of the crust at stable geological settings.

The recent discovery of benzonitrile in a nearby cold molecular cloud (Taurus) marks the first detection of an aromatic species in the interstellar medium by radio astronomy. Benzonitrile provides a key link to benzene, which may be a low-temperature precursor to more complex polycyclic aromatic hydrocarbons (PAHs). Understanding the origin of PAHs will help answer fundamental questions about their role in forming interstellar dust as well as potentially prebiotic molecules—material that may be incorporated into new planetary systems. Computational models are used to pinpoint individual chemical pathways by inputting kinetic rates of various formation and destruction reactions and aiming to reproduce the molecular abundances determined by radio astronomy. Many of these rates have not been measured in the laboratory, especially at low temperature. The MIRAGE project aims to measure reaction kinetics of functionalized benzenes at temperatures relevant to the cold interstellar medium and use these measurements to understand radio observations of aromatics in Taurus molecular cloud. To do this, we will use a new technique in development at the Université de Rennes 1 that combines chirped-pulse (sub)mm-wave (CPMW) rotational spectroscopy with uniform supersonic flows generated by the CRESU technique. This apparatus (one of only a few in development worldwide) will be used to measure kinetics for reactions of benzene. These data are critical to accurately explain the observed abundance of benzonitrile, as well as predicting the abundances of other aromatic species currently targeted for detection.