Despite being far from having reached 'artificial general intelligence' - the broad and deep capability for a machine to comprehend our surroundings - progress has been made in the last few years towards a more specialised AI: the ability to effectively address well-defined, specific goals in a given environment, which is the kind of task-oriented intelligence that is part of many human jobs. Much of this progress has been enabled by deep reinforcement learning (DRL), one of the most promising and fast-growing areas within machine learning. In DRL, an autonomous decision maker - the "agent" - learns how to make optimal decisions that will eventually lead to reaching a final goal. DRL holds the promise of enabling autonomous systems to learn large repertoires of collaborative and adaptive behavioural skills without human intervention, with application in a range of settings from simple games to industrial process automation to modelling human learning and cognition. Many real-world applications are characterised by the interplay of multiple decision-makers that operate in the same shared-resources environment and need to accomplish goals cooperatively. For instance, some of the most advanced industrial multi-agent systems in the world today are assembly lines and warehouse management systems. Whether the agents are robots, autonomous vehicles or clinical decision-makers, there is a strong desire for and increasing commercial interest in these systems: they are attractive because they can operate on their own in the world, alongside humans, under realistic constraints (e.g. guided by only partial information and with limited communication bandwidth). This research programme will extend the DRL methodology to systems comprising of many interacting agents that must cooperatively achieve a common goal: multi-agent DRL, or MADRL.

Historically, the discovery, development and application of metals have set the pace for the evolution of human civilisation, driven the way that people live, and shaped our modern societies. Today, metals are the backbone of the global manufacturing industry and the fuel for economic growth. In the UK, the metals industry comprises 11,100 companies, employs 230,000 people, directly contributes £10.7bn to the UK GDP, and indirectly supports a further 750,000 employees and underpins some £200bn of UK GDP. As a foundation industry, it underpins the competitive position of every industrial sector, including aerospace, automotive, construction, electronics, defence and general engineering. However, extraction and processing of metals are very energy intensive and cause severe environmental damage: the extraction of seven major metals (Fe, Al, Cu, Pb, Mn, Ni and Zn) accounts for 15% of the global primary energy demand and 12% of the global GHG emission. In addition, metals can in theory be recycled infinitely without degradation, saving enormous amounts of energy and CO2 emission. For instance, compared with the extraction route, recycling of steel saves 85% of energy, 86% GHG emission, 40% water consumption and 76% water pollution. Moreover, metals are closely associated with resource scarcity and supply security, and this is particularly true for the UK, which relies almost 100% on the import of metals. The grand challenge facing the entire world is decoupling economic growth from environmental damage, in which metals have a critical role to play. Our vision is full metal circulation, in which the global demand for metallic materials will be met by the circulation of secondary metals through reduce, reuse, remanufacture (including repair and cascade), recycling and recovery. Full metal circulation represents a paradigm shift for metallurgical science, manufacturing technology and the industrial landscape, and more importantly will change completely the way we use natural resources. Full metal circulation means no more mining, no more metal extraction, and no more primary metals. We will make the best use of the metals that we already have. We propose to establish an Interdisciplinary Circular Economy Centre, CircularMetal, to accelerate the transition from the current largely take-make-waste linear economy to full metal circulation. Our ambition is to make the UK the first country to realise full metal circulation (at least for the high-volume metals) by 2050. This will form an integral part of the government's efforts to double resource productivity and realise Net Zero by 2050. We have assembled a truly interdisciplinary academic team with a wide range of academic expertise, and a strong industrial consortium involving the full metals supply chain with a high level of financial support. We will conduct macro-economic analysis of metal flow to identify circularity gaps in the metals industry and to develop pathways, policies and regulations to bridge them; we will develop circular product design principles, circular business models and circular supply chain strategies to facilitate the transition to full metal circulation; we will develop circular alloys and circular manufacturing technologies to enable the transition to full metal circulation; and we will engage actively with the wider academic and industrial communities, policy makers and the general public to deliver the widest possible impact of full metal circulation. The CircularMetal centre will provide the capability and pathways to eliminate the need for metal extraction, and the estimated accumulative economic contribution to the UK could be over £100bn in the next 10 years.