26,313 research outputs found

    The development of the Kent coalfield 1896-1946

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    One of the unique features of the Kent Coalfield is that it is entirely concealed by newer rocks. The existence of a coalfield under southern England, being a direct link between those of South Wales, Somerset and Bristol in the west and the Ruhr, Belgium. and northern France in the east, was predicted by the geologist R. A. C. Godwin-Austen as early as 1856. It was, however, only the rapid increase in demand for Britain's coal in the last quarter of the nineteenth century that made it worth considering testing this hypothesis. The first boring was made in the years 1886-90, and although it discovered coal, this did not in itself prove the existence of a viable coalfield. This could be done only by incurring the heavy cost of boring systematically over a wide area. As the financial returns from such an undertaking were uncertain, it was not surprising that in the early years, around the turn of the century, a dominant role was played by speculators, who were able to induce numerous small investors to risk some of their savings in the expectation of high profits. As minerals in Britain were privately owned, the early pioneer companies not only had to meet the cost of the exploratory borines, but also, if they were not to see the benefit of their work accrue to others, lease beforehand the right to mine coal from local landowners in as much of the surrounding area as possible. This policy was pursued most vigorously by Arthur Burr, a Surrey land specula tor, who raised capital by creating the Kent Coal Conoessions Ltd. and then floating a series of companies allied to it. Burr's enterprise would probably have been. successful had it not been for the water problems encountered at depth in -v- the coalfield. As a result, the Concessions group found itself in control of most of the coalfield, but without the necessary capital to sink and adequately equip its 01ffi collieries. By 1910, however, the discovery of iron ore deposits in east Kent, coupled with the fact that Kent coal was excellent for coking purposes, began to attract the large steel firms of Bolckow, Vaughan Ltd. and Dorman, Long & Co. Ltd. in to the area. The First World War intervened, however, to delay their plans, and to provide an extended lease of life to the Concessions group, which, by the summer of 1914, was facing financial collapse. By the time Dorman, Lone & Co, in alliance with Weetman Pearson (Lord Cowdray), had acquired control over the greater part of the coalfield from the Concessions group, not only was the country's coal industry declining, but so was its steel industry, which suffered an even more severe rate of contraction during the inter-war years. As a result, Pearson and Dorman Long Ltd. was forced to concentrate just on coal production, and this in turn was hampered not only by the water problems, but also by labour shortages and the schemes introduced by the government in 1930 to restrict the country's coal output, in an attempt to maintain prices and revenue in the industry. Nevertheless, production did show a substantial increase between 1927 and 1935, after which it declined as miners left the coalfield to return to their former districts, where employment opportunities were improving in the late thirties. Supporting roles were played in the inter-war years by Richard Tilden Smith, a share underwriter turned industrialist with long standing interests in the coalfield, who acquired one of the Concessions group's two collieries, and by the Powell Duffryn Steam Coal Co. Ltd., which through subsidiary companies, took over the only colliery to be developed by a pioneer company outside the Concessions group. The impossibility of Kent coal, because of its nature, ever gaining more than token access to the more lucrative household market, and then the failure of the local steel industry to materialise meant that the -vi- companies had to develop alternative outlets for their growing outputs. Although nearness to industrial markets in the south-east of England did confer certain advantages were poor consolation for the hoped for developments of either the early pioneers or the later industrialists. Instead of the expected profits, the companies mostly incurred losses, and only the company acquired by Powell Duffryn ever paid a dividend to its shareholders in the years before nationalisation. From the point of view of the Kent miners, the shortage of labour in the coalfield, particularly in the years 1914-20 and 1927-35, was to an important extent responsible for their being amongst the highest paid in the industry. At the same time the more favourable employment opportunities prevailing in Kent compared with other mining districts enabled the Kent Nine Workers Association to develop into a well organised union, which on the whole was able to look after the interests of its members fairly successfully. Throughout the period 1896 to 1946 the Kent Coalfield existed very much at the margin of the British coal industry. Its failure to develop substantially along the lines envisaged by either the early pioneers or by the later industrialists meant that its importance in national terms always remained small

    Modelling uncertainties for measurements of the H → γγ Channel with the ATLAS Detector at the LHC

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    The Higgs boson to diphoton (H → γγ) branching ratio is only 0.227 %, but this final state has yielded some of the most precise measurements of the particle. As measurements of the Higgs boson become increasingly precise, greater import is placed on the factors that constitute the uncertainty. Reducing the effects of these uncertainties requires an understanding of their causes. The research presented in this thesis aims to illuminate how uncertainties on simulation modelling are determined and proffers novel techniques in deriving them. The upgrade of the FastCaloSim tool is described, used for simulating events in the ATLAS calorimeter at a rate far exceeding the nominal detector simulation, Geant4. The integration of a method that allows the toolbox to emulate the accordion geometry of the liquid argon calorimeters is detailed. This tool allows for the production of larger samples while using significantly fewer computing resources. A measurement of the total Higgs boson production cross-section multiplied by the diphoton branching ratio (σ × Bγγ) is presented, where this value was determined to be (σ × Bγγ)obs = 127 ± 7 (stat.) ± 7 (syst.) fb, within agreement with the Standard Model prediction. The signal and background shape modelling is described, and the contribution of the background modelling uncertainty to the total uncertainty ranges from 18–2.4 %, depending on the Higgs boson production mechanism. A method for estimating the number of events in a Monte Carlo background sample required to model the shape is detailed. It was found that the size of the nominal γγ background events sample required a multiplicative increase by a factor of 3.60 to adequately model the background with a confidence level of 68 %, or a factor of 7.20 for a confidence level of 95 %. Based on this estimate, 0.5 billion additional simulated events were produced, substantially reducing the background modelling uncertainty. A technique is detailed for emulating the effects of Monte Carlo event generator differences using multivariate reweighting. The technique is used to estimate the event generator uncertainty on the signal modelling of tHqb events, improving the reliability of estimating the tHqb production cross-section. Then this multivariate reweighting technique is used to estimate the generator modelling uncertainties on background V γγ samples for the first time. The estimated uncertainties were found to be covered by the currently assumed background modelling uncertainty

    How to Be a God

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    When it comes to questions concerning the nature of Reality, Philosophers and Theologians have the answers. Philosophers have the answers that can’t be proven right. Theologians have the answers that can’t be proven wrong. Today’s designers of Massively-Multiplayer Online Role-Playing Games create realities for a living. They can’t spend centuries mulling over the issues: they have to face them head-on. Their practical experiences can indicate which theoretical proposals actually work in practice. That’s today’s designers. Tomorrow’s will have a whole new set of questions to answer. The designers of virtual worlds are the literal gods of those realities. Suppose Artificial Intelligence comes through and allows us to create non-player characters as smart as us. What are our responsibilities as gods? How should we, as gods, conduct ourselves? How should we be gods

    In search of 'The people of La Manche': A comparative study of funerary practices in the Transmanche region during the late Neolithic and Early Bronze Age (250BC-1500BC)

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    This research project sets out to discover whether archaeological evidence dating between 2500 BC - 1500 BC from supposed funerary contexts in Kent, flanders and north-eastern Transmanche France is sufficient to make valid comparisons between social and cultural structures on either side of the short-sea Channel region. Evidence from the beginning of the period primarily comes in the form of the widespread Beaker phenomenon. Chapter 5 shows that this class of data is abundant in Kent but quite sparse in the Continental zones - most probably because it has not survived well. This problem also affects the human depositional evidence catalogued in Chapter 6, particularly in Fanders but also in north-eastern Transmanche France. This constricts comparative analysis, however, the abundant data from Kent means that general trends are still discernible. The quality and volume of data relating to the distribution, location, morphology and use of circular monuments in all three zones is far better - as demonstrated in Chapter 7 -mostly due to extensive aerial surveying over several decades. When the datasets are taken as a whole, it becomes possible to successfully apply various forms of comparative analyses. Most remarkably, this has revealed that some monuments apparently have encoded within them a sophisticated and potentially symbolically charged geometric shape. This, along with other less contentious evidence, demonstrates a level of conformity that strongly suggests a stratum of cultural homogeneity existed throughout the Transmanche region during the period 2500 BC - 1500 BC. The fact that such changes as are apparent seem to have developed simultaneously in each of the zones adds additional weight to the theory that contact throughout the Transmanche region was endemic. Even so, it may not have been continuous; there may actually have been times of relative isolation - the data is simply too course to eliminate such a possibility

    Anytime algorithms for ROBDD symmetry detection and approximation

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    Reduced Ordered Binary Decision Diagrams (ROBDDs) provide a dense and memory efficient representation of Boolean functions. When ROBDDs are applied in logic synthesis, the problem arises of detecting both classical and generalised symmetries. State-of-the-art in symmetry detection is represented by Mishchenko's algorithm. Mishchenko showed how to detect symmetries in ROBDDs without the need for checking equivalence of all co-factor pairs. This work resulted in a practical algorithm for detecting all classical symmetries in an ROBDD in O(|G|³) set operations where |G| is the number of nodes in the ROBDD. Mishchenko and his colleagues subsequently extended the algorithm to find generalised symmetries. The extended algorithm retains the same asymptotic complexity for each type of generalised symmetry. Both the classical and generalised symmetry detection algorithms are monolithic in the sense that they only return a meaningful answer when they are left to run to completion. In this thesis we present efficient anytime algorithms for detecting both classical and generalised symmetries, that output pairs of symmetric variables until a prescribed time bound is exceeded. These anytime algorithms are complete in that given sufficient time they are guaranteed to find all symmetric pairs. Theoretically these algorithms reside in O(n³+n|G|+|G|³) and O(n³+n²|G|+|G|³) respectively, where n is the number of variables, so that in practice the advantage of anytime generality is not gained at the expense of efficiency. In fact, the anytime approach requires only very modest data structure support and offers unique opportunities for optimisation so the resulting algorithms are very efficient. The thesis continues by considering another class of anytime algorithms for ROBDDs that is motivated by the dearth of work on approximating ROBDDs. The need for approximation arises because many ROBDD operations result in an ROBDD whose size is quadratic in the size of the inputs. Furthermore, if ROBDDs are used in abstract interpretation, the running time of the analysis is related not only to the complexity of the individual ROBDD operations but also the number of operations applied. The number of operations is, in turn, constrained by the number of times a Boolean function can be weakened before stability is achieved. This thesis proposes a widening that can be used to both constrain the size of an ROBDD and also ensure that the number of times that it is weakened is bounded by some given constant. The widening can be used to either systematically approximate an ROBDD from above (i.e. derive a weaker function) or below (i.e. infer a stronger function). The thesis also considers how randomised techniques may be deployed to improve the speed of computing an approximation by avoiding potentially expensive ROBDD manipulation

    Quantitative analysis of phase transitions in two-dimensional XY models using persistent homology

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    We use persistent homology and persistence images as an observable of three different variants of the two-dimensional XY model in order to identify and study their phase transitions. We examine models with the classical XY action, a topological lattice action, and an action with an additional nematic term. In particular, we introduce a new way of computing the persistent homology of lattice spin model configurations and, by considering the fluctuations in the output of logistic regression and k-nearest neighbours models trained on persistence images, we develop a methodology to extract estimates of the critical temperature and the critical exponent of the correlation length. We put particular emphasis on finite-size scaling behaviour and producing estimates with quantifiable error. For each model we successfully identify its phase transition(s) and are able to get an accurate determination of the critical temperatures and critical exponents of the correlation length

    ‘We the People: Supporting Food SMEs towards a Circular Food Economy’

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    This single Case Study locates SME (small and medium-size enterprise) hospitality and food services (HaFS) within a complex food waste system. It examines collaborative support for business change from linear resource wastage (‘take, use, dump), towards a circular food economy (CfE)- where ‘designing out’ food waste may reap savings. The objective is to support SME uptake of waste aversion practices so that they may thrive. The qualitative research centers on a London-based project promoting food waste valorization and healthy nutrition, in 15 boroughs. That project’s outreach for broad-based, collective impact included HaFS that are SMEs. Cross-sector liaison was the research focus for this Case Study which utilizes a hybrid philosophy and meta-framework, based on Critical Realism and Systemic Thinking. Some reference to Interpretivism highlights stewardship values for transforming individual behaviour. The Study also uses a multi-method design, borrowing soft systems from Management Science and Operational Research. Its blended approach includes: participant observation, mapping and rich picture techniques, semi-structured interviews and focus groups. The main research questions align concepts such as: circular economy, cross-sector collaboration and food waste management- with HaFS that are SMEs. A framework method and Leximancer software supported coding and qualitative thematic analysis. Primary findings include interesting categories of analytical, NGO and policy literature. Although conversations flagged up pivotal roles for our health and education sectors, the food SME element still seems peripheral in this transition to regenerative business. A ‘people vibe’ is enabling some HaFS’ kitchen waste action and food redistribution and, academia is a potential contributor to this information resource flow among stakeholders. The Study’s unique onto-epistemological framework enhances philosophical and theoretical knowledge about promoting SME resource stewardship. It spans Systemic Thinking (overt connections and acute complexities) and Critical Realism (deep mechanisms and institutional power differentials, impacting change). As an interpretive lens, the framework’s contribution to praxis was tested by shadowing the London TRiFOCAL project. This research could inform a business policy shift from traditional supply chain thinking, towards active UK food citizenship
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