2,605 research outputs found

    South Wales

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    Carboniferous rocks in this region occur in a broadly east-west trending syncline, the core of which includes the South Wales and Pembrokeshire coalfields (Fig. 5.1). Tournaisian and Visean strata (Avon and Pembroke Limestone groups) represent deposition on a southward prograding carbonate ramp evolving into a carbonate shelf (Wright 1987), in a succession which shows similarities to that of the Bristol and Mendips areas (Chapter 6). The main outcrops, in south Pembrokeshire, Gower and the Vale of Glamorgan, occur along the southern periphery of the coalfields and are commonly affected by Variscan thrusting and folding. Thinner successions occur along what is termed the East Crop and North Crop of the South Wales Coalfield, where much of the Visean succession is absent due to sub-Namurian and intra-Visean unconformities. Namurian fluvio-deltaic deposits (Marros Group) flank the South Wales and Pembrokeshire coalfields. Much of the lower and middle Namurian succession is absent across the region, except in the west of the South Wales Coalfield where only small parts are absent beneath an intra-Namurian unconformity. Westphalian fluvio-lacustrine deposits (South Wales Coal Measures Group) form the South Wales and Pembrokeshire coalfields, located to the east and west of Carmarthen Bay, respectively. Westphalian to Stephanian Pennant alluvial facies (Warwickshire Group) occur in the core of the South Wales Coalfield syncline. Deposition of the South Wales Coal Measures and Warwickshire groups was probably laterally contiguous with those in the Bristol and Somerset coalfields (Chapter 6), but the Usk-Cowbridge High controlled and restricted sedimentation for much of the Carboniferous, with pre-Namurian uplift and erosion removing the Tournaisian and Visean succession. Later uplift is also believed to have caused attenuation of the Warwickshire Group in the east of the South Wales Coalfield. The lithostratigraphical nomenclature for the region is that of Waters et al. (2007; 2009)

    Computational studies on gas phase polyborate anions

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    The borate anions [B(OH)4]�, [B2O(OH)5]�, [B3O3(OH)4]�, [B3O3(OH)5]2�, [B3O3(OH)6]3�, [B4O5(OH)4]2�, [B5O6(OH)4]�, and [B7O9(OH)5]2� (2 isomers) and the neutral orthoboric and metaboric acids, B(OH)3 and B3O3(OH)3, have been structurally optimised in the gas phase at the B3LYP/6-311++G(d,p) level. Energetic data, combined with analogous data for �building blocks� H2O and [OH]�, has enabled their relative gas phase stabilities (all exothermic) to be determined using an isodesmic approach as: [B5O6(OH)4]� > [B3O3(OH)4]� > [B(OH)4]� > [B7O9(OH)5]2� > [B4O5(OH)4]2� > [B3O3(OH)5]2�. The two isomers of [B7O9(OH)5]2� have similar total energies although the �ribbon� isomer is calculated to be more stable by only 10.0 kJ mol�1. QTAIM analyses have been undertaken on all computed structures, and QTAIM charges for H, O and B atoms have been calculated. It is concluded that H-bond interactions dominate the solid-state energetics of non-metal cation polyborate salts

    Lithostratigraphy of the Old Red Sandstone successions of the Anglo-Welsh Basin

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    This report presents a revised lithostratigraphy of the Old Red Sandstone of the Anglo-Welsh Basin, prepared under the auspices of the British Geological Survey (BGS) Stratigraphical Framework Committee (SFC). The report provides a correlation of the successions in different parts of the basin and rationalises group and formation nomenclature for the outcrops of Old Red Sandstone in England and Wales. It is based on a previous discussion document (Barclay, unpublished MS, 2007) which presented options in a three-step approach towards rationalisation to a proposed single, standard scheme that can be applied to most of the Pridoli–Lochkovian succession (lower part of the Lower Old Red Sandstone) of the Anglo-Welsh Basin. The earlier discussion document was circulated among geologists with expertise in the Old Red Sandstone of the Anglo-Welsh Basin in and outside the British Geological Survey. This version takes account of the suggestions for improvement and comments made during the consultation process. One significant change from previous classifications concerns the base of the Old Red Sandstone. There is a consensus that this should be placed at the base of the first major incoming of red- or green-bed (‘Old Red Sandstone’) terrestrial facies, thereby excluding the shallow marine Downton Castle Sandstone and Tilestones formations that have traditionally been included in the Old Red Sandstone. The report proposes the introduction of two new names and group status for the successions traditionally referred to as the Lower Old Red Sandstone and Upper Old Red Sandstone. The two successions are separated by the major, regional, cleavage-forming Acadian unconformity, and because of this, the authors have made a case for giving them supergroup status. However, they are here accorded group status in accordance with practice in the other Old Red Sandstone basins of the United Kingdom, both onshore and offshore. In nationwide standardisation, all the groups are informally referred to the as-yet undefined parent ‘Old Red Sandstone Supergroup’, although the authors propose that the term ‘Old Red Sandstone’ is best retained as a facies (or magnafacies) term. The Lower Old Red Sandstone is termed the Daugleddau Group and the Upper Old Red Sandstone is termed the Brecon Beacons Group

    Pentaborate(1-) salts templated by substituted pyrrolidinium cations: synthesis, structural characterization, and modelling of solid-state H-bond interactions by DFT calculations

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    The synthesis and characterization of a series of pentaborate(1�) salts of substituted pyrrolidinium cations [C4H8NH2][B5O6(OH)4] (1), [C4H8NMe2][B5O6(OH)4] (2) [C4H8NMeH][B5O6(OH)4] (3), [(2-CH2OH)C4H7NH2][B5O6(OH)4] (4) is reported. All compounds were characterized by single-crystal XRD studies with 3 (1/2CH3COCH3) and 4 (1/2H2O) solvated. TGA/DSC analysis of the pentaborates 1�4 showed that they thermally decomposed in air at 800 °C to 2.5 B2O3, in a 2 step process involving dehydration (<250 °C) and oxidative decomposition (250�600 °C). BET analysis of materials derived thermally from the pentaborates 1 and 2 had internal porosities of <1 m2 g�1, indicating they were non-porous. All compounds show extensive supramolecular H-bonded anionic lattices. H-bond interactions are described in detail and motifs found in these and in other pentaborate structures have been examined and modelled by DFT calculations. These calculations confirm that H-bonds interactions in pentaborates are moderately strong (ca. �10 to �21 kJ mol�1) and are likely to dominate the energetics of their templated syntheses

    Current Drive by Electron Bernstein Waves in Spherical Tori

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    Acceleration and Classical Electromagnetic Radiation

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    Classical radiation from an accelerated charge is reviewed along with the reciprocal topic of accelerated observers detecting radiation from a static charge. This review commemerates Bahram Mashhoon's 60th birthday.Comment: To appear in Gen. Rel. Gra

    Merger Control and The Rule of Law

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    This article asks whether competition law, in particular the law on mergers, should always be called law. It concentrates on merger control in the European Union but draws on US experience and history to provide ideas and to contribute to the framework for the analysis. The starting point is that competition law is increasingly located not in courts but in agencies: in the EU, the European Commission. These agency regulators take decisions based allegedly on economic theory, but which are non-predictable and non-replicable; they do not provide a tight enough reasoning process to serve as a guide to action in future cases. Yet they are only marginally reviewable by courts. Finally, even insofar as identifiable and coherent rules exist for agency behaviour, their rule-like character is undermined by a culture of negotiation and compromise, which means that the link between rule and decision becomes even more tenuous and even less apparent to the non-party. Over-reliance on questionable economics, as well as inadequately constrained agency behaviour, suggests that merger control is now the domain of ad-hoc decision making as much as it is of law

    Chemisorption theory of ammonia on copper

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    We present local-density-approximation calculations of ammonia adsorption on copper clusters of different sizes (6 to 18 atoms) modelling the (100) and (111) surface. Including for some of the copper atoms only one instead of eleven electrons explicitly in the calculation, did not always work satisfactorily. Comparison of adsorption energies for clusters of related geometry indicates a preference for onefold adsorption. This is due to the Pauli repulsion of the lone-pair orbital of ammonia with the copper 3d electrons. which is minimal for onefold adsorption. as well as an interaction with 4s electrons, which is most attractive in the onefold geometr
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