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Faults, fractures and fluids in mudstones during Cenozoic extension in the Cleveland Basin
Get PDFFractures and faults may act as important fluid-flow pathways through low permeability mudstone sequences; understanding their occurrence and properties is thus important when considering the risks of leakage of petroleum from underlying reservoirs, or CO2 from storage sites. Fluid-flow is also an important in radioactive waste storage sites during construction or operation of the sites. This project studies calcite-filled fractures and faults developed within the exhumed, early-mature, Jurassic mudstone succession of the Cleveland Basin, NE England, combining structural geology with isotope geochemistry and geochronology. The abundance of well-exposed, natural fractures with different orientations and failure modes provides an opportunity to investigate the properties of these fractures and provides a basin-wide temporal and spatial framework of evolving deformation.
Calcite veins and fault fills are present in N-S to NNW-SSE trending normal faults and associated fractures in the north of the Cleveland Basin. U-Pb calcite geochronology has yielded ages in the range 45-20Ma for sampled calcite. This describes a previously unrecognised phase of Cenozoic faulting. I propose that this deformation relates salt-related deformation following regional tilting, uplift and eastwards gravity sliding related to Atlantic opening and the development of the proto-Icelandic plume to the NW of Britain.
Structural and petrographic observations suggest that N-S trending faults have complex kinematic and fluid-flow histories. Faults are characterised by damage zones with widespread calcite mineralisation, extensional jog structures and fracture reactivation. Stable isotope and clumped isotope analyses suggest that the regional fracture-controlled fluid-flow during the Cenozoic deformation involved post-exhumation mixing of cool meteoric waters (20°C) with warmer (80°C) basinal fluids. I hypothesise that fluid is driven by gravity-driven regional extension. Whilst fault-related displacements are modest, meaning that the structures are unlikely to be widely resolved in offshore seismic reflection profiles, they are widespread and therefore are inferred to represent highly effective fluid-flow pathways. Our findings place new important constraints on the poorly constrained Cenozoic tectonic history of the Cleveland Basin and northeast Britain
Renewable hydrogen production by aqueous phase reforming of oxygenated biomass over hydrotalcite derived Ni/Mg/Al catalysts
Get PDFThe conversion, selectivity for hydrogen, and stability of different Ni based hydrotalcite derived catalysts were studied in aqueous phase reforming of ethylene glycol and phenol and were benchmarked against Ni/γ-Al2O3 and commercial 5 wt.% Pt/C and 5 wt.% Pd/C. Hydrotalcite catalysts were given a nomenclature as aNib, were ‘a’ is M2+/M3+ ratio and ‘b’ is Ni loading. The highest conversion obtained was for 3Ni20 catalyst giving a mass activity of 24.4 mmol of substrate per g of catalyst (38% conversion), which was similar to the mass activity of commercial 5 wt.% Pt/C and 5 wt.% Pd/C catalyst. However, selectivity for hydrogen of commercial catalysts was at least 1.5 times more than 3Ni20. The highest selectivity for hydrogen for hydrotalcite derived catalyst was obtained with 8Ni15 catalyst, which was similar to the selectivity obtained by Pt/C, however, mass activity of 8Ni15 was only 11.5 mmol of substrate per g of catalyst. With an increase in Ni loading in Ni-hydrotalcite derived catalysts (keeping the M2+/M3+ ratio constant) conversion of ethylene glycol increased (3Ni5 3Ni10 > 3Ni15 > 3Ni20). With an increase in M2+/3+ ratio (keeping Ni loading constant) conversion of ethylene glycol decreased (2Ni15 > 3Ni15 > 6Ni15 > 8Ni15) but the selectivity to hydrogen increased (2Ni15 < 3Ni15 < 6Ni15 < 8Ni15). Monometallic Ni/γ-Al2O3 demonstrated poorer selectivity compared to all hydrotalcite derived catalysts. Post reaction pXrd patterns showed that the hydrotalcite structure was changed to a spinel structure (in case of hydrotalcite derived catalysts) and boehmite in case of Ni/γ-Al2O3. Ni leaching was lower in hydrotalcite derived catalysts as compared to monometallic Ni/γ-Al2O3, except for sample 8Ni15, indicating that higher Mg content can negatively affect catalyst stability. Spent 2Ni15, 3Ni20 and Pd/C were re-tested in APR of ethylene glycol. For hydrotalcite derived catalysts, conversion dropped by 50% as compared to fresh catalyst while conversion remained almost same in Pd/C. Selectivity for hydrogen of spent and fresh catalysts were almost same. The major reason for deactivation was leaching of Ni. With the increase in reduction temperature, conversion increased but the selectivity dropped. In case of aqueous phase reforming of phenol, no conversion of phenol was observed with any catalyst and consequently, no hydrogen was produced, in contrast to literature reports
The Controls on Vanadium, Iron and Zinc Stable Isotope Fractionation in Upper Crustal Plutons
Get PDFChemically diverse plutonic rocks make up most of the upper continental crust, but the exact crystal-liquid segregation processes and physical conditions in solidifying mush bodies are debated. Transition metal stable isotopes are increasingly used to investigate magmatic processes, but knowledge of their specific behaviour in plutonic settings is lacking. Better understanding of the cause(s), magnitudes and directions of isotope fractionation in relatively simple, closed system plutons is required to assess the efficacy of transition metal stable isotopes at investigating mush processes.
This thesis investigated the calc-alkaline Boggy Plain Zoned Pluton, SE Australia, and the tholeiitic Red Hill Intrusion, Tasmania. This was the first time that the Fe-V-Zn isotopic composition of whole rock powders and mineral separates from closed system suites have been interpreted in combination with detailed textural observations, which provided a more comprehensive understanding of the controls of isotope fractionation in plutonic settings.
Fractional crystallisation was the major control on Fe and V isotopic trends, whereas Zn isotopic fractionation was mostly driven by fluids. It was observed that the isotopic composition of powders from coarse-grained, cumulative rocks does not necessarily represent a true melt composition, questioning the assumptions and modelling approaches of many previous studies of intrusive rocks. Instead, a focus on mineral separates was more informative, and enabled derivation of the first temperature-dependent mineral-melt fractionation factors for calc-alkaline magmas, and development of a new method for calculating melt composition from mineral separate data, which will be useful for future studies. The magnitudes of fractionation factors were overwhelmingly influenced by temperature, whereas changing fO2 had no resolvable effect. Hence, accurate temperature estimates and temperature-dependent fractionation factors are vital for future work on plutonic settings. The isotopic variability observed on the pluton-scale highlights the significant isotopic heterogeneity of the upper crust in general. This has implications for how accurately clastic sediments record changes in ‘average’ crustal isotopic composition over geological timescales, and thus understanding temporal changes in the isotopic compositions of the crust and oceans
Non-linear galaxy clustering in modified gravity cosmologies
Get PDFWe present \textsc{MG-GLAM}, a code developed for the very fast production of full -body cosmological simulations in modified gravity (MG) models. We describe the implementation, numerical tests, and first results of a large suite of cosmological simulations for a wide range of viable MG models. The code is highly optimised, with a tremendous speedup of a factor of more than a hundred compared with earlier -body codes, while still giving accurate predictions of the matter power spectrum and dark matter halo abundance. \textsc{MG-GLAM} is ideal for the generation of large numbers of MG simulations that can be used in the construction of mock galaxy catalogues and the production of accurate emulators for ongoing and future galaxy surveys.
The coming generation of galaxy surveys will provide measurements of galaxy clustering with unprecedented accuracy and data size, which will allow us to test cosmological models at a much higher precision than previously achievable.
This means that we must have more accurate theoretical predictions to compare with future observational data.
As a first step toward more accurate modelling of the redshift space distortions (RSD) of small-scale galaxy clustering in modified gravity cosmologies, we investigate the validity of the so-called Skew-T (ST) probability distribution function (PDF) of halo pairwise peculiar velocities in these models. We show that combined with the streaming model, the ST PDF substantially improves the small-scale predictions by incorporating skewness and kurtosis, for both cold dark matter (CDM) and two leading MG models: gravity and the DGP braneworld model. The ST model reproduces the velocity PDF and redshift-space halo clustering measured from MG -body simulations down to highly non-linear scales. By performing a simple Fisher analysis, we find a significant increase in constraining power to detect modifications of General Relativity by introducing small-scale information in the RSD analyses.
We introduce an emulator-based halo model approach for non-linear clustering of galaxies in modified gravity cosmologies. We construct accurate emulators, i.e. simulation-based theoretical templates, using neural networks for basic halo properties than can be calculated robustly from -body simulations. The dark matter halo emulators can be combined with a halo-galaxy connection model to predict the galaxy clustering statistics down to non-linear scales through the halo model
Planetary Giant Impacts: Simulating Moon-Forming Collisions
Get PDFGiant impacts between proto-planets were a common event in our solar system 4.5 billion years ago. However, understanding their details and consequences is still an open problem. In this thesis I use smoothed particle hydrodynamics to study how pre-impact spin of the proto planets could affect the hypothesised giant impact that formed the Earth--Moon system, as well as developing tools to improve the numerical methods applied to these studies
Roma-ness in Music, Music in Roma-ness: The Musical Craft of Slovak Roma in Klenovec and Kokava
Get PDFThis PhD thesis is an ethnographic case study exploring practices of professional music-making among Roma in two municipalities in south-central Slovakia: Klenovec and Kokava nad Rimavicou. It is based on long-term ethnographic research carried out from 2013; most of the ethnographic data presented in this thesis were collected between 2018 and 2019 during a dedicated period of PhD fieldwork. The introductory chapter outlines the main research questions by describing the development of the research focus for the thesis, and it introduces the principal research methods – ethnographic and visual. The first findings chapter is an ethnographic description of the location in question, with a special focus on socio-cultural, socio-political and socio-economic conditions and the lives of local Roma under these conditions. The second chapter deals with Romani ethnic identity in the locality; it employs theories of (Romani) ethnicity, describes how this is typically manifest and discusses its significance for professional music-making. The third chapter is based on theories from economic anthropology and looks at Romani professional music-making from the perspective of economic exchange, considering it as an income-generating activity and a distinctive cultural practice. The fourth and last findings chapter looks at Roma-ness in music – a form of enactment of Romani ethnic specificity in the context of professional music-making – framed by impression management theories. The concluding chapter revisits the research questions, indicates paths for further research, critically evaluates the research methodology and reflects upon the positionality of the research. The thesis is complemented with audio-visual material resulting from various visual methods – work with photographs, video and film. These are accessible online through links and QR codes
Towards Smarter Electric Vehicle Charging with Low Carbon Smart Grids: Pricing and Control.
Get PDFEnvironmental and political directions indicate transition to a decarbonized transportation system is necessary as it is one of the most pollutant sectors regarding greenhouse gas emissions. Research in Demand Side Management suggests that its tools are the most cost-effective option for improving the performance of the grid without incurring into high infrastructure investments, hence reducing the payback for start-ups in the sector. This Thesis proposes solutions to tackle 5 objectives around this area of research: 1-2 are related to developing a demand response pricing and EV smart charging strategies, 3-4 are related to developing a multi-objective charging scheme in order to ensure fairness and reduction of CO2eq emissions, and 5 is related to testing parameters of EV charging to understand future improvements and limitations in the proposed models. Chapter 3, that tackles objectives 1-2, proposes a data-driven optimisation algorithm with pricing and control modules that communicate with each other to achieve a successful integration with the grid by charging at the right price and expected time. The results show customers can be positively engaged with pricing signals while providing support to the grid. Chapter 4, which tackles objectives 3-4, proposes a multi-objective EV charging formulation that include perspectives of EV users, a carbon regulator and a charging station operator. The multi-objective formulation is solved with a genetic algorithm in order to find the fairest and the greenest solution. Results which are evaluated using different scenarios show different weights to each objective function can differ based on the charging location and EV charging availability. Finally, Chapter 5 which tackles objective 5, shows a sensitivity analysis where improvements in revenues, reduction of carbon emissions and bidding capacity depend on the evaluation of EV users’ parameters, and the charging station control and sizing
Complexity and physical activity policy: considerations for theory and practice.
Get PDFBackground:
Complex systems perspectives have been increasingly adopted to address physical inactivity. Within this, myriad policy actions are deemed important for supporting population physical activity and creating so-called ‘active systems.’ I argue that complexity and systems-thinking have, prior to this thesis, predominantly been applied uncritically and with insufficient consideration of the agents who influence, and are influenced by, the complexity of the physical activity policy environment. There is the need to connect different strands of research, specifically in relation to physical activity policy, evidence-informed Public Health, and complexity.
Aim:
My research aimed to critically assess the understanding and application of complexity theories as a basis for evidence-informed physical activity policy efforts. Specifically, I sought to interrogate the suitability of complexity theories for influencing, developing and implementing physical activity policies; identify conditions that enable more effective complex systems approaches to physical activity policy and programmes; and in doing so, extend understanding concerning complexity theories and their application.
Theory and methods:
Central to my theoretical position has been a reflexive process in which I have located myself within the wider physical activity and Public Health research landscape, and crucially the system I seek to change. This thesis is underpinned by a complex realist ontology, and epistemologically I draw on the notion of different lenses of evidence about policy issues. Methodologically, I employed qualitative and action-orientated methods to explore individuals’ agency and experiences of the physical activity policy system. My own observations and experiences are discussed through a theoretical pluralism.
Study 1:
I explored the processes, values and experiences of physical activity policy-makers in UK national government, in relation to complexity, and how they sought to foster system change. I conducted 10 semi-structured interviews. Three overarching themes were constructed and emphasised that while the idea of complex systems permeated the physical activity sector, uncertainty as to the meaning of complexity and its implications may preclude its application in ways that enhance physical activity policies and programmes. I highlight problematic practices and identify potentially important mechanisms to support system change.
Study 2:
This study was originally a preliminary component of an action research project that was curtailed by the SARS-Cov-2 pandemic. Through five in-depth semi-structured interviews, I examined how local partnerships can be used more effectively to improve the implementation of national physical activity policies. Specifically, I extended knowledge by providing a critical reflection on system leadership, demonstrating how it is enabled and strengthened, how it links to implementation, and how changes in systemic practices and cultures can be stimulated in the physical activity policy domain.
Study 3:
This study responded to outstanding gaps in the evidence, in particular the ongoing uncertainty around the practical applications of complexity theories and systems perspectives. In-keeping with my intended action-orientated approach, I convened a workshop with 19 international experts (from research, policy and practice) to critically reflect on my previous research, drawing attention to issues of conceptual purity and discord between the theory and practice of complexity in the physical activity policy domain. Thereafter, the workshop explored how to optimise the application of complex systems approaches to physical activity policy, by focusing on the action of knowledge mobilisers. Analysis led to the creation of four propositions for advancing complexity theories and systems-based approaches, which set out important considerations concerning the how, when, and why of applying these perspectives.
Concluding remarks:
The general discussion is presented not as a line in the sand, but as both an advancement on previous thinking, and reflection on these and empirical contributions that remain a work in progress. Specifically, I set out current conceptualisations of complexity theories as they pertain to physical activity policy, and discuss considerations for future practice. I conclude by arguing that a reorientation of efforts across research, policy and practice toward agency, mobilisation and application of complex systems perspectives in physical activity policy settings will strengthen collective impact
Modelling farmer and consumer preferences for cleaner food production
Get PDFAgriculture in Pakistan is currently unsustainable due to intensive farming practices – the concentrated use of agricultural inputs, including water and agrochemicals. The widespread use of intensive farming has dire effects on both human health and the natural environment. As such the antidote to these problems would be the adoption of sustainable agriculture. The present research proposes to reduce the use of agrochemicals such as pesticides and fertilisers, and adopt efficient irrigation technology in tomato cultivation in district Khushab Pakistan. Discrete choice experiment (DCE) approach is deployed to study farmer and consumer preferences and their valuation of the proposed changes to facilitate the adoption of sustainable agriculture in tomato cultivation. Questionnaire data is used to investigate farmer and consumer perceptions and understanding of existing farming practices and proposed changes.
Findings reveal that majority farmers and consumers are aware of the unfavourable health and environmental impacts of existing farming practices used in tomato cultivation. Empirical analysis of questionnaire data show that farmers who own their farmland and those who have received the training to apply agrochemicals are more likely to have a positive perception of the proposed changes. Likewise, consumers who have more awareness and information about different farming practices and a greater health consciousness are more keen to see the changes in existing farming practices. DCE analysis shows that farmers prefer the reduction in the use of pesticide and fertiliser use, but place a negative value on the adoption of drip irrigation. On the other hand, consumers not only prefer the proposed changes, but their willingness to pay (WTP) to implement the proposed changes is higher than the farmers’ willingness to accept (WTA). This implies that the proposed changes in current farming practices used for tomato cultivation are economically viable, and hence that market-based approaches to control agricultural pollution may be more effective than regulations in Pakistan
The effects of future climate change on physiological traits and competitive abilities of invasive riparian plants Impatiens glandulifera and Heracleum mantegazzianum
Get PDFOver the last few centuries, human activity has greatly contributed to different forms of global change, such as climate change and biological invasions, with great consequences for biodiversity and ecosystem services. The interactions between these factors need to be taken into consideration more carefully in order to better predict and mitigate negative impacts. Many recent studies have speculated about the possible effects of climate change on plant invasions. Riparian habitats have been repeatedly described in the literature as being highly susceptible to invasions by non-indigenous plant species. Due to the dynamic nature of rivers, it is likely that river systems will be very responsive to changing conditions, such as water temperature and altered hydrology. This thesis focuses on two of the most well-known and widespread riparian invasive species in Europe, Impatiens glandulifera Royle and Heracleum mantegazzianum Sommier & Levier.
I investigated the ways in which the performance and competitive abilities of these species might be affected by increased temperatures and climate-induced changes in soil moisture, respectively, as well as the future distributions of these species in Europe. Firstly, increased temperatures directly impacted the physiological and life-history traits of both invasive and native plants and, thus, competition outcomes for the invaded plant communities. Results suggested that warming might hinder invasion success in I. glandulifera, by quickening its life cycle and increasing growth of stems at the expense of biomass accumulation in roots and leaves, as well as by promoting the suppression of invader root growth by native species. Secondly, soil moisture seemed to have clear effects on the competition between H. mantegazzianum and co-occurring native species. Changes in soil moisture affected native species to a greater extent than the invader, increasing the community’s susceptibility to invasion. Notably, excessive soil moisture experienced at the beginning of the growth season favoured invasion by H. mantegazzianum through reducing the native community’s biomass, while simultaneously having little effect on the invader’s biomass. However, drought conditions inhibited the growth and competitive abilities of H. mantegazzianum as well, even when biotic resistance from the native community was also low. Finally, species distribution models revealed that future warming could reduce the ranges of these species in Europe, as they shift northwards to Scandinavia and to higher altitudes. Nevertheless, as observations about competitive outcomes between invasive and co-occurring native species are highly context-dependent and can vary depending on the scale of the study and the species involved, it is crucial to examine multiple facets of these complex relationships. Riparian invasions could interact with other forms of global change in the near future in complex, species-specific and scale-dependent ways which need to be targeted by future researchers
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