Chemical-looping combustion (CLC) is an innovative process for the combustion of fuels with in situ CO2 separation. In contrast to other carbon capture technologies, the large energy or cost penalties caused by gas separation are avoided since CO2 separation is intrinsic to the process. The development of a scalable production method for cost-effective, durable oxygen carriers is essential for the future ommercialisation of the CLC technology. The oxygen carrier particles will be tested in novel reactors. The rate of oxygen release and uptake will be performed using two different reactors and the kinetics of reactions involved will be characterisation.

Carbon dioxide produced by burning fossil fuels such as oil and gas is building up in the atmosphere and causing the planet to warm. The oceans have absorbed more than 90% of the heat trapped on the planet to date. However, this heating also causes the ocean to expand, leading to rising sea level and consequently to an increased risk to and vulnerability of people and industries located near the coast. Understanding how much sea level will change into the future allows us to plan accordingly the defences we need to install in order to safeguard the infrastructure and livelihoods of our coastal communities. Warming of the ocean is not geographically uniform however, as ocean currents move heat around the globe. This leads to contrasting changes in ocean temperature and sea level (affecting coastal communities and assets). By the end of the century, some regions may experience very large sea level rises of up to a metre while others will see far less (or even a lowering). This science program will use observations made from research ships and computer models of the ocean to understand where the ocean takes up heat from the atmosphere and how ocean currents transport and redistribute that heat. To study ocean currents we need a 'tracer' - something that is placed in and moves with the flow, like a chemical dye. Although not intentionally for this purpose, three varieties of tracers have been added to the atmosphere since the 1950s and have since gradually been absorbed into the ocean, and redistributed by ocean currents. These are radioactive carbon (produced by mid 20th century nuclear bomb tests), chlorofluorocarbons (historically used in refrigerators and aerosol cans, and which caused an expansion of the Ozone Hole) and more recently sulphur-hexafluoride (formerly found in tennis balls but now predominantly used in electrical industries as an insulator). These tracers have entered the ocean as distinct pulses at different times, forming a fortuitous experiment we can now observe. We will use high-precision equipment to measure these tracers in the Atlantic and Southern Oceans and collaborate with international partners to track their global fate. We will use these observations to estimate the rate at which heat is being absorbed and re-distributed throughout the ocean and to assess and improve climate model predictions of regional sea level rise.

Palaeomagnetic recordings in ancient rocks and meteorites hold the key to answering some of the most fundamental questions in Earth Sciences. Theories regarding the evolution of the geodynamo, the thermal evolution of the Earth's core, plate tectonics and palaeogeography, and the formation of the solar system, are all constrained by observations of the ancient fields trapped in rocks that are hundreds or even thousands of millions of years old. However, not all palaeomagnetic observations are reliable, because the magnetic signal carried by most rocks and meteorites is dominated by a poorly understood thermoremanent magnetisation (TRM) in grains with non-uniform magnetic structures. Most palaeomagnetic interpretations are based on the assumption that such TRMs are carried by magnetically uniform, single domain (SD) particles, whose behaviour is well described by Néel's SD TRM theories. However, slightly larger grains with non-uniform magnetic structures are ubiquitous in nature. These are termed pseudo-SD (PSD) as they display some characteristics to SD grains (such as a large magnetic remanence), but can have a significantly different recording fidelity. Presently there is no physical model for PSD TRM acquisition therefore we have no means of assessing the stability and reliability of many palaeomagnetic signals. This proposal will address the urgent need to quantify the fundamental behaviour of PSD TRM. In particular we aim to address two key issues that can affect palaeomagnetic fidelity: (a) PSD stability as a function of time and temperature, and (b) their TRM dependence on cooling rates. This will be achieved by developing a three-dimensional numerical model that incorporates the effects of thermal-fluctuations. It will then be possible to model PSD TRM acquisition and assess the accuracy with which PSD domain states can record a geomagnetic field. A key aspect of the numerical modelling is validation of the predicted domain structures, as a function of grain size and temperature, against direct nano-metric-scale experimental observations. This will be achieved using a remarkable set of highly characterised artificial samples (produced by an electron lithography process in a previous NERC-funded study) and using the advanced transmission electron microscope (TEM) technique of off-axis electron holography, which is able to image the magnetisation on a nano-metric scale. Experiments will also be conducted on bulk samples, including a suite of already collected lavas. Once validated, the numerical model will be used to explore the fidelity of TRM recordings and palaeointensity (ancient geomagnetic field intensity) determinations in a range of grain geometries applicable to natural samples containing PSD domain states. The research will result in a comprehensive understanding of TRM acquisition for PSD grains of magnetite, which are thought to the dominant carrier of palaeomagnetic recordings, and identify how accurately PSD grains can record the ancient field. The predictive micromagnetic model we develop will be able to directly address a number of key issues, for example: (1) Palaeointensity estimates from PSD magnetites are used to constrain models of the Earth's core dynamics and the Solar System's formation. We will be able to determine whether these palaeointensities are likely to under or over estimate the true value of the ancient field. (2) Archaen palaeointensity estimates are often determined from PSD magnetite crystals, embedded with in single-silicate crystals extracted from gabrros. The model will allow us to quantify the effect of long-term cooling-rates on TRM intensity, something which cannot be done experimentally. With increased accuracy of palaeomagnetic observations, a much clearer picture will emerge of the past behaviour of the geomagnetic field, and hence a far better hope of unravelling the true nature of the early universe and the evolution and behaviour of the Earths deep interior.