This project will develop new HPC software that may be applied across a wide range of computational resources from local Beowulf clusters, through to institutional level HPC (such as offered by the White Rose Grid) and up to national HPC resources where necessary. The primary purpose of the software will be to provide accurate three-dimensional models of chemical diffusion through realistic models of mammalian skin. The software developed will enable scientists who seek to understand diffusion processes through such membranes using computational modelling to be able to undertake simulations with more complexity, and hence more realism, that is currently feasible. Our plan is to further develop existing three-dimensional finite element research code, resulting from highly successful, previously funded, EPSRC projects, into robust parallel software that is applicable to a wide range of HPC resources. The reliable modelling, and prediction, of the diffusion of chemicals through skin membranes is a problem that is of great importance to society as a whole. For example, understanding the mechanisms of how penetration into the body occurs is essential in order to predict the consequences of accidental exposure and also when seeking to apply drugs therapeutically to a patient. The main outcome from this project will be a software tool that will enable much more physically realistic cases to be considered than in any previous work. This tool will be usable by non-experts (in computational science) and will be able to fully explore the heterogeneous structure of skin, and how this effects the rate of penetration of a wide range of substances.

Sir Humphrey Davy discovered clathrate hydrates in 1811. Hydrates are solid structures formed by water and gases, e.g., methane. The abundance of natural gas hydrate deposits across the world could provide abundant energy resources for the future, as well as long-term CO2 storage. Natural gas hydrates can be exploited in high-tech applications including innovative water-desalination and gas-storage processes. Prof. Carolyn Koh overviewed hydrates in the book she co-authored with Prof. Dandy Sloan: Clathrate Hydrates of Natural Gases, 3rd Ed., CRC Press, 2007. This proposal is concerned with hydrate plugs in oil & gas pipelines. Such plugs can lead to pipelines ruptures, causing spills and environmental disasters, production interruptions, and even loss of life. The traditional approach to manage hydrates is adding thermodynamic inhibitors (THIs), e.g., methanol. THIs shift the conditions at which hydrates are stable to lower Ts and higher Ps. However, large amounts of THIs are necessary, which negatively affects both the economics of the operations and their environmental impact. Among emerging promising technologies to prevent hydrates formation in pipelines is the use of 'low dosage hydrate inhibitors' (LDHIs), effective at low concentrations. Among other limitations, the wide applicability of LDHIs is impeded by a current lack of understanding of how LDHIs function. In fact, LDHIs performance depends on oil composition, water salinity, temperature, etc. LDHIs include kinetic hydrate inhibitors (KHIs) and anti-agglomerants (AAs). This timely project will develop a fundamental understanding regarding how AAs function. The project builds on significant prior results. For example, Prof. Koh and her group produced extensive experimental data regarding the performance of LDHIs, and developed extensive experimental characterisation capabilities to probe AAs at different length scales (from the microscopic, using micromechanical force measurements, to the macroscopic, using flow loops). Prof. Striolo employed molecular simulations to discover possible molecular mechanisms that are responsible for the performance of LDHIs (in particular, AAs). The simulation results led to new LDHIs formulations, environmentally benign, recently disclosed in a patent application. To widely adopt LDHIs, it is required to develop reliable models that accurately describe the likelihood of hydrate plugs formation as a function of process conditions. This project will transform the pioneering software CSMHyK, which is already coupled with the industry-standard multiphase flow simulator OLGA. CSMHyK (1) describes accurately multi-phase transport in pipelines; (2) uses reliable equations of state to predict the hydrates thermodynamic stability; and (3) employs working assumptions to predict hydrates formation. To enable the latter feature, an important parameter is the nucleation sub-cooling, which is treated as an input parameter currently estimated from experimental flow-loop results, thus lacking predictability. To render CSMHyK predictive, it is proposed to develop a model, based on kinetic Monte Carlo (KMC), to describe quantitatively the hydrate population dynamics as a function of system conditions. The new model will allow practitioners to quantify LDHIs' effects, which is currently not possible, as well as to include molecular-level information from microscopic experiments and molecular simulations into the formulation of risk assessment. This NSF-EPSRC Lead Agency Agreement proposal builds on an Expression of Interest submitted to EPSRC on 04/08/2018, which was approved on 19/09/2018. The project benefits from strong industrial interest, and from established collaborations. The collaboration between Striolo and Koh was enabled by their industrial partner Halliburton and by a Royal Society International Collaboration grant. Striolo and Stamatakis collaborate in a project in which KMC was implemented to study fluid transport.

Dilute gases of alkali atoms are now routinely cooled to within a millionth of a degree of absolute zero using laser light, permitting them to be confined in traps formed due to the interaction of the atom with either an applied magnetic field or a far-detuned off-resonant laser beam. Further cooling by evaporation in such traps leads, in the case of bosonic atoms, to the creation of a new state of matter, known as a Bose-Einstein condensate, in which the quantum mechanical nature of the particles dominates over their classical behaviour. Such condensates are often viewed as the atomic or matter-wave equivalent of coherent laser light. Since their first observation in 1995, Bose-Einstein condensates have been used with great success to investigate a vast range of physical phenomena from fundamental studies of superfluidity to strongly correlated many-body states in optical lattices, providing insight into more complicated condensed matter systems. This success stems from two important features of ultracold quantum gases. Firstly, from an experimental stand-point, ultracold atomic gases are readily manipulated and controlled with external electromagnetic fields (dc, radio-frequency, microwave and optical) permitting a very high degree of real-time flexibility in the experimental configuration and highly sensitive detection. Secondly, Bose-Einstein condensates have proved theoretically tractable, due largely to their dilute, weakly interacting nature, leading to a deeper understanding of experimental observations. This makes ultracold quantum gases an ideal testing ground for the cutting-edge developments in our theoretical understanding of the behaviour of many-body quantum systems. Here, we propose a program of fundamental research intended to yield a better general understanding of the dynamics of non-equilibrium interacting quantum many-body systems, using atomic Bose-Einstein condensates of 85Rb. Specifically, we will exploit a collision resonance (known as a Feshbach resonance) between two 85Rb atoms to tune the atomic interactions in the condensate to be attractive, thereby generating bright matter-wave solitons; robust, non-dispersive atomic wave-packets confined to propagate in one dimension, in which the attractive atomic interactions exactly compensate the usual dispersion. Solitons arise as solutions to nonlinear partial differential equations describing a diverse range of physical systems. First observed in the shallow water of the Union Canal in Scotland in 1834, solitons have since been studied in many other contexts, including nonlinear optics, biophysics, astrophysics and particle physics. In the atomic context, the underlying quantum nature of the system provokes sophisticated many-body quantum treatments to accurately capture the essential physics. This proposal describes a systematic, closely interlinked experimental-theoretical study of such "quantum" bright matter-wave solitons with a view to exposing the coherence and entanglement properties of bright solitons, whilst developing new advanced theoretical treatments applicable to other quantum many-body systems. Working together with the leading international experts in the field, we aim ultimately to assess the feasibility of using quantum bright solitons to generate Schrödinger cat states for quantum-enhanced interferometry. The proposed research falls within the remit of two of the identified current Grand Challenges in Physics, "Emergence and Physics Far From Equilibrium" and "Quantum Physics for New Quantum Technologies", and thereby contributes to UK science in areas where there is recognised potential for significant societal and economic impact.

The goal of the proposed research is to develop two in-situ sensor systems that measure in-ground gas concentrations and strain/moisture/temperature/suction at different scales in order to provide data on the dynamics of gas flux and soil structure. One is based on distributed fiber optic sensor (DFOS) system that can provide measurements at meters to kilometers-scale, whereas the other is based on low-power sensor coupled with in-ground mesh-network wireless sensor network (WSN) system that provides data at selected local points in distributed manner. Both technologies are currently being prototyped at UC Berkeley (UCB). The developed sensor systems will be trialed first in the unique wind tunnel-soil experimental facility available at the Colorado School of Mines (CSM). We propose an experimental plan designed to manipulate soil moisture fluctuations by balancing subsurface water introduction through precipitation events and losses to evaporation and evapotranspiration as controlled by atmospheric perturbations (temperature, wind speed, and relative humidity) so as to make more informed biogeochemical predictions and soil structure changes under changing climate conditions. Under the controlled environment, we will quantify the precision errors of the developed sensor systems. The developed systems will also be implemented in the fields of Rothamsted Research (RR) to examine its feasibility in the actual field conditions. The ultimate goal is to improve the predictive understanding of how atmospheric carbon loading is affected by soil structure changes. The proposed sensor development and experimental research will lead to a substantial improvement of soil carbon models such as the RothC model developed at RR]. Each compartment in the model decomposes by a first-order process with its own characteristic rate. The IOM compartment is resistant to decomposition. The model adjusts for soil texture and its changes by altering the partitioning between CO2 evolved and (BIO+HUM) formed during decomposition, rather than by using a rate modifying factor, such as that used for temperature. Moreover, total CO2 effluxes are largely controlled by root respiration, and microbial respiration of soil organic matter including rhizospheric organic carbon and all of these processes are highly sensitive to soil structure. In this proposed research, we therefore hypothesize that soil structure change is strongly linked to soil gas generation. We will develop and implement sensor systems that measure both, which in turn will allow us to quantify the link. These new models will in the future allow the effects of soil management on carbon dynamics to be predicted and hence give an understanding of the impact of different soil management strategies (e.g. tillage) on soil sustainability. The research will complement ongoing field research at RR supported by the BBSRC in the National Capability scheme and in ISP funding streams; especially on the delivery of nutrients to plants. The processes to be studied in the project are expected to lead to improved formulations to include multi-scale, multi-physics under development at RR by: (1) more rationally representing the coupled surface-subsurface processes, (2) including vegetation hydrodynamics and carbon and nutrient allocation, and (3) incorporating soil and genome-enabled subsurface reactive transport models that have explicit and dynamic microbial representation. The project will lead to the development of spatially-distributed sensing systems in the field that can (1) sense changes in soil stricture and (2) link these changes to fluxes of N2O, CH4, CO2 and O2 into and from soils.

Meeting the Paris climate change commitments will be extraordinarily challenging, and even if they are met, may require extensive global deployment of greenhouse gas removal (GGR) technologies resulting in net negative emissions. If certain major emitters do not meet their Paris commitments and/or wider international cooperation is reduced then the trajectory needed to reduce emissions to Paris levels after a delay will be even more severe, potentially leading to the need for even greater reliance on such net negative emissions technologies. At present, the technical feasibility, economics, implementation mechanisms and wider social and environmental implications of GGR technologies remain relatively poorly understood. It is highly uncertain that GGR technologies can be implemented at the scales likely to be required to avoid dangerous climate change and without causing significant co-disbenefits or unintended consequences. Our GGR proposal presents a unique combination of a multi-scale assessment of the technical performance of GGR technologies with an analysis of their political economy and social license to operate, with a particular focus on how these elements vary around the world and how such considerations impact region-specific GGR technology portfolios. Currently, some portray GGR technologies as a panacea and virtually the only way of meeting aggressive climate targets - an essential backstop technology or a 'bridge' to a low-carbon future. One part of our project is to work with the models of the global economy (integrated assessment models) and better reflect these technologies within those models but also to use models at different scales (global, regional, national, laboratory scales) to understand the technologies better. We also seek to better understand how deployment of these technologies interact with the climate system and the carbon cycle and what the implications are for the timings of wide-scale rollout. By contrast, sceptics have expressed concerns over moral hazard, the idea that pursuing these options may divert public and political attention from options. Some critics have even invoked terms such 'unicorns', or 'magical thinking' to describe the view that many GGR technologies may be illusory. We will seek to understand these divergent framings and explicitly capture what could emerge as important social and political constraints on wide-scale deployment. As with nuclear power, will many environmentalists come to view GGR technologies as an unacceptable option? Understanding the potential scaling up of GGR technologies requires an understanding of social and political concerns as well as technical and resource constraints and incorporating them in engineering, economic and climate models. This aspect of our proposal necessarily brings together social science, engineering and environmental sciences. What is the biggest challenge to scaling up BECCS for example? Is it the creation of the sustainable biomass supply chain, the deployment of CO2 capture technology or the transport and storage infrastructure that is rate limiting? Or is it more likely the social acceptability of this technology? Further, we will provide insight into the value of international and inter-regional cooperation in coordinating GGR efforts. For e.g., would it make more sense for the UK to import biomass, convert it to electricity and sequester the CO2, or would it be preferable pay for this to happen elsewhere? Conversely, how might the UK benefit from utilising our relatively well characterised and extensive CO2 storage infrastructure in the North Sea to store CO2 on behalf of both the UK and others? More generally, we will explore how stakeholders in key regions view the suite of GGR technologies. Finally, we will quantify the option value of GGR - what is the value in early deployment of GGR technologies? How does it provide flexibility in meeting our near term carbon targets?