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The ERC-funded FRAGSUS Project (Fragility and sustainability in small island environments: adaptation, cultural change and collapse in prehistory, 2013–18), led by Caroline Malone (Queens University Belfast) has explored issues of environmental fragility and Neolithic social resilience and sustainability during the Holocene period in the Maltese Islands. This, the first volume of three, presents the palaeo-environmental story of early Maltese landscapes. The project employed a programme of high-resolution chronological and stratigraphic investigations of the valley systems on Malta and Gozo. Buried deposits extracted through coring and geoarchaeological study yielded rich and chronologically controlled data that allow an important new understanding of environmental change in the islands. The study combined AMS radiocarbon and OSL chronologies with detailed palynological, molluscan and geoarchaeological analyses. These enable environmental reconstruction of prehistoric landscapes and the changing resources exploited by the islanders between the seventh and second millennia bc. The interdisciplinary studies combined with excavated economic and environmental materials from archaeological sites allows Temple landscapes to examine the dramatic and damaging impacts made by the first farming communities on the islands’ soil and resources. The project reveals the remarkable resilience of the soil-vegetational system of the island landscapes, as well as the adaptations made by Neolithic communities to harness their productivity, in the face of climatic change and inexorable soil erosion. Neolithic people evidently understood how to maintain soil fertility and cope with the inherently unstable changing landscapes of Malta. In contrast, second millennium bc Bronze Age societies failed to adapt effectively to the long-term aridifying trend so clearly highlighted in the soil and vegetation record. This failure led to severe and irreversible erosion and very different and short-lived socio-economic systems across the Maltese islands.

This repository contains the data related to the Data in Brief article titled: Bulk and critical material demand for selected ‘Starter Kit’ energy system models. The data include the modeled mass of materials and their embodied emissions. A metadata file is also included to clarify the units, materials and scenario names.

Currently, fossil fuels make up a significant proportion of global energy demand and cause many concerns, such as increasing greenhouse gas emission. Therefore, there is a considerable need for cost-effective, facile and efficient processing of environmental-friendly energy harvesting and storage systems. Solar energy is one of the most promising energy sources that meet the energy demand. The silicon-based solar cells exhibit competitive power conversion efficiency and dominate the solar cell market in recent years. In contrast, organic solar cells (OSCs) have emerged as promising third-generation photovoltaic devices owing to their outstanding properties such as the potential of low-cost mass manufacturing, lightweight, mechanical flexibility and easy processability. Therefore, OSCs have received growing attention from the research community. For solar cell technologies, a smectic liquid crystal C8-BTBT was selected in Chapter 3 due to its unique thermal dynamic and crystal properties. A range of ternary OSCs with and without C8-BTBT loading at gradient weight fractions were thermally treated and fabricated. In addition, the assessment of fabricated OSCs on the photovoltaic characteristics reveals the evolution of various cell parameters with annealing temperature and C8-BTBT weight fractions. The cell with 5 wt% C8-BTBT loading exhibited the best performance after thermal annealing treatment at 120 oC. Furthermore, flexible hydrogel substrates were fabricated for flexible OSCs in Chapter 4. The PHEMA hydrogel films were optimised via adjusting photopolymerisation duration under UV light. Based on the fabricated PHEMA substrates, flexible OSCs were subsequently made, whose extracted device parameters showed comparable characteristics with those in Chapter 3. Moreover, PHEMA-based OSCs can be dissolved in different types of polar solvents, which is promising for realising sustainable and recyclable solar cells. For the development of energy storage devices, asymmetric carbon nanohorns were proposed as an active material to fabricate flexible solid‐state carbon wire (CW)‐based electrochemical supercapacitors (ss‐CWECs) which exhibited high power density and ultra‐low cutoff frequency. Based on microscopy and electrochemical characterisation, the fundamental reaction mechanism in polyvinyl‐based electrolyte system was elucidated in Chapter 5, as being associated with deprotonation reaction under the acid, base, and elevated temperature conditions. In Chapter 6, by using activated carbon, multi‐walled carbon nanotubes, and single‐wall carbon nanohorns as hybrid electrode materials (5:1:1), remarkable specific length capacitance of 48.76 mF cm−1 and charge-discharge stability (over 2000 times cycles) of ss‐CWECs were demonstrated, which are the highest reported to date. Furthermore, a high‐pass filter for eliminating ultra‐low electronic noise was demonstrated, enabling an optical Morse Code communication system to be operated. vThe collective works in this thesis demonstrate novel energy conversion and storage applications with the liquid crystal in OSCs and carbon nanoparticles in supercapacitors. These results provide a step forwards in the development of energy conversion and storage devices for a more efficient energy system.

AbstractThe production of clean fuels and chemicals from waste feedstocks is an appealing approach towards creating a circular economy. However, waste photoreforming commonly employs particulate photocatalysts, which display low product yields, selectivity, and reusability. Here, a perovskite‐based photoelectrochemical (PEC) device is reported, which produces H2 fuel and simultaneously reforms waste substrates. A novel Cu30Pd70 oxidation catalyst is integrated in the PEC device to generate value‐added products using simulated solar light, achieving 60–90% product selectivity and ≈70–130 µmol cm−2 h−1 product formation rates, which corresponds to 102–104 times higher activity than conventional photoreforming systems. The single‐light absorber device offers versatility in terms of substrate scope, sustaining unassisted photocurrents of 4–9 mA cm−2 for plastic, biomass, and glycerol conversion, in either a two‐compartment or integrated “artificial leaf” configuration. These configurations enable an effective reforming of non‐transparent waste streams and facile device retrieval from the reaction mixture. Accordingly, the presented PEC platform provides a proof‐of‐concept alternative towards photoreforming, approaching more closely the performance and versatility required for commercially viable waste utilization.

Achieving reductions in global anthropogenic emissions necessary to mitigate the worst effects of climate change will require significant reductions in energy demand. However, there are concerns that energy demand reductions involving lifestyle and behavioural changes might negatively impact peoples’ wellbeing. The work in this thesis studies the impacts of how people spend their time – commonly known as time-use – to try to understand whether this is the true, or whether energy demand could be reduced while improving wellbeing. Using the UK as a case study, this issue is examined by determining the energy use and wellbeing attributes of different activities and lifestyles, by modelling the impacts of shifts in time-use between activities, and by comparing the importance of three specific changes that might impact future energy use and wellbeing. Firstly, based upon existing literature it is identified that there is a need to better understand the combined energy and wellbeing impacts of different activities and lifestyles. Combining UK time-use and energy consumption data, the energy intensity, enjoyment and sociability of time is studied. Comparing these metrics for different activities suggests that since the most enjoyable (and in some cases sociable) activities are generally the least energy-intensive, acceptable (or popular) lifestyle changes might exist that reduce national energy use and improve wellbeing. However, studying changes between 2000 and 2015 shows that while the population’s time became less energy-intensive, there was little change in average enjoyment and a reduction in sociability. Segmenting the population by age reveals that an ageing population could present a challenge since energy use broadly increases with age-group while social contact reduces. However, comparing occupations highlights opportunities for specific actions that could improve wellbeing and reduce energy use, while regional differences suggest that wellbeing might be improved without increasing energy use. Having determined the energy intensity and wellbeing associated with different uses of time, the impacts of possible time-use changes are then studied. Acknowledging the difficulty in trying to predict how people might choose to re-allocate time in different situations, a sensitivity-based approach is used to study the impacts of a wide range of possible shifts in time between activities. The approach is then applied to explore the impacts of extreme lifestyle changes associated with COVID-19 lockdown measures in the UK and validated against real-world observations during the pandemic. While activity changes associated with lockdown measures reduce energy use, there are varying implications for peoples’ wellbeing, with the youngest appearing to be most negatively impacted but those able to work from home potentially benefiting. Although lockdown measures prevented some of the most enjoyable and sociable activities from happening, alternative activity changes could be supported in future that reduce energy use while improving wellbeing. Finally, time is used as a basis to compare the importance of different types of changes and help to prioritise actions. This is demonstrated by studying the combined impacts of three example changes – greater home working, changes in commuting transport modes and car intensity – on office workers’ energy use and wellbeing. The results show that working from home could have a greater impact upon office workers’ average energy use and enjoyment than changes to commuting modes, but that the social contact provided by the office could be difficult to replace. The study also demonstrates different ways that energy savings might be achieved through home working, shifts in commuting modes and changes to vehicle intensity. This approach could be used more widely to compare a broader range of changes, understand their interactions and different ways to achieve outcomes, and help to identify those changes that are most important to reduce energy use and improve wellbeing. The work presented in this thesis shows that time-use can be used as a basis to examine energy demand and wellbeing together. Using time-use to link these issues enables trade-offs or co-benefits due to different uses of time to be determined and allows rebound effects to be considered. The results suggest that reducing energy use can be achieved at the same time as improving wellbeing. The hope is that the approaches and findings presented in this thesis can provide a basis for wider discussion and a platform for future work to support climate change mitigation strategies that are positive for both the environment and society.

A decision support tool has been developed, which uses global multi-objective optimisation based on: (i) the environmental impacts, evaluated within the framework of full life cycle assessment, and (ii) process costs, evaluated using rigorous process models. This approach is particularly useful in developing the bio renewable-based energy solutions and chemicals manufacturing, where multiple criteria must be evaluated and where the optimisation-based decision making process is particularly attractive. The framework is demonstrated using a case study of conversion of terpenes derived from bio-waste feedstocks into reactive intermediates. A two-step chemical conversion/separation sequence was implemented as a rigorous process model and combined with a life cycle model. A life cycle inventory for crude sulfate turpentine was developed, as well as a conceptual process of its separation into pure terpene feedstocks. The performed single- and multi-objective optimisations demonstrate the functionality of the optimisation-based process development and illustrate the approach. Most significant advance is the ability to perform multi-objective global optimisation, resulting in identification of a region of Pareto-optimal solutions.

Demonstrating the generation of electricity with Accelerator-Driven Subcritical Reactor (ADSR) technology will incur substantial financial risk both from traditional reactor construction uncertainties and new technology uncertainties such as the reliability of the accelerator system. The sensitivity of the economic value of ADSRs to the reliability of the accelerator system is assessed. The economic assessment considers an ADSR with either one or two linear accelerators driving it. The extent to which a second accelerator improves reliability is determined, as are the costs for that improvement. Two Real Options derived flexible designs for the accelerator system are also considered. In one a single accelerator ADSR can be expanded to having two accelerators, in the other an accelerator is constructed and tested before the reactor is designs for the accelerator system are also considered. In one a single accelerator ADSR can be expanded to having two accelerators, in the other an accelerator is constructed and tested before the reactor is constructed. Finally, a phased multiple-reactor park with a single system of multiple integrated accelerators is suggested and discussed.

The main research question in this paper is whether the installation rate of solar pv technology is affected by social spillovers from spatially close households. The installed base, defined as the cumulative number of solar v installations within a neighbourhood by the end of a particular month, serves as a measure for the social effects of interest. Motivated by the technology-specific time lag between the decision to adopt a solar Pv panel and the completion of the installation, the third lag of the installed base serves as main regressor of interest in the panel data model employed. The results suggest small, but positive and significant social effects that can be exploited to promote adoption: at the average installation rate of 0.7 installations per 1,000 owner-occupied households, one more solar PV panel in the postcode district increases the installation rate three months later by one percent. At the average number of 6,629 owner–occupied households within a postcode district, this implies an increase in the number of new installations in the neighbourhood by 0.005. Projects involving a high number of installations could hence promote diffusion. A major limitation of the model is that social spillovers are assumed to spread within defined neighbourhoods, only. spatial econometric methods could allow for social effects across these borders.

This research investigates ways to reduce the carbon dioxide emissions from the cement industry. Cement is one of the largest sources of man-made greenhouse gases, contributing ~5% of the global total. 40% of emissions from cement come from the fuel used in the process, while the electricity used contributes a further 5%. The focus of the research is to find operational changes that can reduce emissions without the need for large capital investment. Three cement plants in the UK were investigated using four different mathematical models based on real data from the plants. A new metric for assessing the environmental impact of the fuel mix of a plant was proposed, and evidence indicates that it may be a better predictor of environmental performance than the metrics currently used in industry. The research found that consistently improving this fuel metric to best-observed levels, as well as reducing the excess air ratio to industry-standard levels had the potential to reduce fuel consumption by up to 7%, and fuel derived CO2 emissions by up to 12%. Increasing use of biomass to best-observed levels had the potential to reduce the net fuel derived CO2 emissions by up to 20%. Comparing the proposed improvements to the historic range of plant performance showed that this level of performance is within the normal operating range of the plants. A reduction of 2-4% in electricity costs and electricity derived emissions was also possible from operational changes. These savings would reduce operating costs as well as emissions, and require little to no capital investment, meaning they could be implemented directly. If successfully implemented in the near future the total savings by 2050 would be on a similar scale to those expected from much more expensive technology changes, such as upgrading to new cement plants, or installing carbon capture and storage technology. EPSRC funded