577 research outputs found

    User guide for 'BGS Civils' : a suite of engineering properties datasets

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    This report is the user’s guide for the national assessment of a suite of seven Engineering Properties datasets. These complimentary datasets provide information and advice on Excavatability, Strength, Discontinuities, Bulking of soils and rocks, Sulfate and sulfide potential, Corrosivity (ferrous) and Use for fill. The purpose of this user guide is to provide the background, overview of the methodology developed by the British Geological Survey, and the potential applications and limitations of this GIS information

    The relationships between effective porosity, uniaxial compressive strength and sonic velocity of intact Borrowdale Volcanic Group Core samples from Sellafield

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    The effective porosity, saturated sonic velocity and saturated uniaxial compressive strength were determined on a large number of Borrowdale Volcanic Group volcaniclastic core samples from three boreholes at Sellafield, Cumbria. The work formed part of the UK Nirex Limited site investigation into whether the Sellafield area could be suitable as a repository for intermediate and low level radioactive waste. Most of the intact samples were of low to very low effective porosity, had a high sonic velocity and were very strong to extremely strong. However, a proportion of values deviated significantly from this. Bivariate analysis showed a negative relationship exists between sonic velocity and effective porosity. The cross plots of these two parameters with uniaxial compressive strength showed a wide range of strength values for samples of low effective porosity and high sonic velocity. Six failure types were identified during the uniaxial compressive strength tests. The strongest samples tended to fail through the matrix and the weakest rock samples tended to fail through haematized material or along haematized veins. Effective porosity and sonic velocity measurements could not distinguish between those samples that failed through the matrix and those that failed along discrete narrow veins. The presence of narrow haematized veins has a major effect on the intact rock strength

    Environmental factors influencing pipe failures

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    This report details work carried out under NERC grants NE/M008339/1 and NE/NO13026/1 which were collaborations between the British Geological Survey and Yorkshire Water, with an additional knowledge transfer component involving Scottish Water and Dŵr Cymru Welsh Water. The work examines whether models developed using environmental, topographical and geohazard information could complement existing management tools, and increase the understanding as to how pipe networks of different materials interact with their broader environment. This can be seen as a first step in identifying ways in which greater resilience could be built into pipe networks

    Emergence of good conduct, scaling and Zipf laws in human behavioral sequences in an online world

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    We study behavioral action sequences of players in a massive multiplayer online game. In their virtual life players use eight basic actions which allow them to interact with each other. These actions are communication, trade, establishing or breaking friendships and enmities, attack, and punishment. We measure the probabilities for these actions conditional on previous taken and received actions and find a dramatic increase of negative behavior immediately after receiving negative actions. Similarly, positive behavior is intensified by receiving positive actions. We observe a tendency towards anti-persistence in communication sequences. Classifying actions as positive (good) and negative (bad) allows us to define binary 'world lines' of lives of individuals. Positive and negative actions are persistent and occur in clusters, indicated by large scaling exponents alpha~0.87 of the mean square displacement of the world lines. For all eight action types we find strong signs for high levels of repetitiveness, especially for negative actions. We partition behavioral sequences into segments of length n (behavioral `words' and 'motifs') and study their statistical properties. We find two approximate power laws in the word ranking distribution, one with an exponent of kappa-1 for the ranks up to 100, and another with a lower exponent for higher ranks. The Shannon n-tuple redundancy yields large values and increases in terms of word length, further underscoring the non-trivial statistical properties of behavioral sequences. On the collective, societal level the timeseries of particular actions per day can be understood by a simple mean-reverting log-normal model.Comment: 6 pages, 5 figure

    UKGEOS: Glasgow Geothermal Energy Research Field Site (GGERFS): initial summary of the geological platform

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    The preferred second UKGEOS site is at Clyde Gateway, in the east end of Glasgow, Scotland. The focus of this, the Glasgow Geothermal Energy Research Field Site (GGERFS), is on characterising and monitoring the subsurface for minewater and hot sedimentary aquifer geothermal energy, and for cooling and heat storage. This report details BGS data and knowledge at late 2016, to define initial characterisation of the ‘geological platform’ relevant for the planning of a geothermal research facility and associated environmental baseline monitoring. The report covers knowledge of the bedrock and superficial deposits geology, abandoned coal mines, hydrogeology, geothermal datasets, geochemistry, remote sensed data, seismicity, stress fields, engineering geology and rock property datasets. BGS holds a great deal of legacy borehole, mining and geochemistry data and has updated existing bedrock and superficial deposits models of the area. However, deep borehole and seismic data are lacking to define the geology and structure of the area below a few hundred metres. Hydrogeological and temperature data are also lacking for the bedrock strata. Regional datasets and knowledge have (and can be further) used to reduce uncertainty and risk in these aspects of the geological characterisation

    The merger of vertically offset quasi-geostrophic vortices

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    We examine the critical merging distance between two equal-volume, equal-potential-vorticity quasi-geostrophic vortices. We focus on how this distance depends on the vertical offset between the two vortices, each having a unit mean height-to-width aspect ratio. The vertical direction is special in the quasi-geostrophic model (used to capture the leading-order dynamical features of stably stratified and rapidly rotating geophysical flows) since vertical advection is absent. Nevertheless vortex merger may still occur by horizontal advection. In this paper, we first investigate the equilibrium states for the two vortices as a function of their vertical and horizontal separation. We examine their basic properties together with their linear stability. These findings are next compared to numerical simulations of the nonlinear evolution of two spheres of potential vorticity. Three different regimes of interaction are identified, depending on the vertical offset. For a small offset, the interaction differs little from the case when the two vortices are horizontally aligned. On the other hand, when the vertical offset is comparable to the mean vortex radius, strong interaction occurs for greater horizontal gaps than in the horizontally aligned case, and therefore at significantly greater full separation distances. This perhaps surprising result is consistent with the linear stability analysis and appears to be a consequence of the anisotropy of the quasi-geostrophic equations. Finally, for large vertical offsets, vortex merger results in the formation of a metastable tilted dumbbell vortex.Publisher PDFPeer reviewe

    Change of nuclear configurations in the neutrinoless double-β\beta decay of 130^{130}Te \rightarrow 130^{130}Xe and 136^{136}Xe \rightarrow 136^{136}Ba

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    The change in the configuration of valence protons between the initial and final states in the neutrinoless double-β\beta decay of 130^{130}Te \rightarrow 130^{130}Xe and of 136^{136}Xe \rightarrow 136^{136}Ba has been determined by measuring the cross sections of the (dd,3^3He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-β\beta decay in these systems.Comment: 10 pages, 4 figures, 9 table

    Understanding the influence of race/Ethnicity, gender, and class on inequalities in academic and non-academic outcomes among eighth-grade students: findings from an intersectionality approach

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    Socioeconomic, racial/ethnic, and gender inequalities in academic achievement have been widely reported in the US, but how these three axes of inequality intersect to determine academic and non-academic outcomes among school-aged children is not well understood. Using data from the US Early Childhood Longitudinal Study—Kindergarten (ECLS-K; N = 10,115), we apply an intersectionality approach to examine inequalities across eighth-grade outcomes at the intersection of six racial/ethnic and gender groups (Latino girls and boys, Black girls and boys, and White girls and boys) and four classes of socioeconomic advantage/disadvantage. Results of mixture models show large inequalities in socioemotional outcomes (internalizing behavior, locus of control, and self-concept) across classes of advantage/disadvantage. Within classes of advantage/disadvantage, racial/ethnic and gender inequalities are predominantly found in the most advantaged class, where Black boys and girls, and Latina girls, underperform White boys in academic assessments, but not in socioemotional outcomes. In these latter outcomes, Black boys and girls perform better than White boys. Latino boys show small differences as compared to White boys, mainly in science assessments. The contrasting outcomes between racial/ethnic and gender minorities in self-assessment and socioemotional outcomes, as compared to standardized assessments, highlight the detrimental effect that intersecting racial/ethnic and gender discrimination have in patterning academic outcomes that predict success in adult life. Interventions to eliminate achievement gaps cannot fully succeed as long as social stratification caused by gender and racial discrimination is not addressed

    Assessing L2 vocabulary depth with word associates format tests: issues, findings, and suggestions

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    Word Associates Format (WAF) tests are often used to measure second language learners’ vocabulary depth with a focus on their network knowledge. Yet, there were often many variations in the specific forms of the tests and the ways they were used, which tended to have an impact on learners’ response behaviors and, more importantly, the psychometric properties of the tests. This paper reviews the general practices, key issues, and research findings that pertain to WAF tests in four major areas, including the design features of WAF tests, conditions for test administration, scoring methods, and test-taker characteristics. In each area, a set of variables is identified and described with relevant research findings also presented and discussed. Around eight topics, the General Discussion section provides some suggestions and directions for the development of WAF tests and the use of them as research tools in the future. This paper is hoped to help researchers become better aware that the results generated by a WAF test may vary depending on what specific design the test has, how it is administered and scored, and who the learners are, and consequently, make better decisions in their research that involves a WAF test
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