2,036 research outputs found

    Interpretation of dispersion relations for bounded systems

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    Constructing normal modes for bounded systems from infinite dispersion relation roots for interpretation of plasma wave and instability studies on finite cylinder

    Analysis of Pt/SnO(sub x) during catalysis of CO oxidation

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    Temperature-programmed reduction using 6kPaH2 suggests that a sample consisting of 3 percent Pt supported directly on SnO2 is, under conditions of catalysis of CO oxidation used here, best represented as 3 percent Pt/SnO sub x, since the support is likely to partially reduced, probably in the vicinity of the metal/oxide interface. Catalytic measurements at 421 to 424 K show that this 3 percent Pt/SnO sub x is significantly more active per unit area of Pt than 6 percent Pt/SiO2 in catalyzing the oxidation of CO. In situ micro-FTIR reveals that while the latter has predominantly linearly bound CO on the surface under reaction conditions, the Pt/SnO sub x also has a species absorbing at 2168 cm(exp -1) which may be CO upon Pt in a positive oxidation state or weakly chemisorbed CO on zero-valent Pt. This may be directly involved in the low temperature oxidation of CO on the Pt/SnO sub x, since being weakly held the activation energy for its surface diffusion to the metal/oxide interface will be low; such mobile species could allow the high rates of surface transport and an increase in the fraction of the surface over which the CO oxidation occurs. FTIR also reveals carbonate-type species on the P/SnO sub c surface

    Calorimetry, activity, and micro-FTIR analysis of CO chemisorption, titration, and oxidation on supported Pt

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    The value of in situ analysis on CO chemisorption, titration and oxidation over supported Pt catalysts using calorimetry, catalytic and micro-FTIR methods is illustrated using silica- and titania-supported samples. Isothermal CO-O and O2-CO titrations have not been widely used on metal surfaces and may be complicated if some oxide supports are reduced by CO titrant. However, they can illuminate the kinetics of CO oxidation on metal/oxide catalysts since during such titrations all O and CO coverages are scanned as a function of time. There are clear advantages in following the rates of the catalyzed CO oxidation via calorimetry and gc-ms simultaneously. At lower temperatures the evidence they provide is complementary. CO oxidation and its catalysis of CO oxidation have been extensively studied with hysteresis and oscillations apparent, and the present results suggest the benefits of a combined approach. Silica support porosity may be important in defining activity-temperature hysteresis. FTIR microspectroscopy reveals the chemical heterogeneity of the catalytic surfaces used; it is interesting that the evidence with regard to the dominant CO surface species and their reactivities with regard to surface oxygen for present oxide-supported Pt are different from those seen on graphite-supported Pt

    2014/15 Skills2Play/Sport programme evaluation

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    The Primary School Physical Literacy Framework reflects the importance of the development of children’s physical literacy; “the motivation, confidence, knowledge and understanding that provides children with the movement foundation for lifelong participation in physical activity.” It also provides clear guidance as to how schools can maximise opportunities to develop the physical literacy of their pupils. Skills2Play and Skills2PlaySport are two complementary primary school physical literacy initiatives designed to support the objectives of the new Framework. Together they comprise the Skills2Play/Sport programme. Throughout this report the term Skills2Play/Sport refers to the programme, comprising both initiatives (Skills2Play and Skills2PlaySport). The programme consists of training and a resource and equipment package, which includes activity cards for both Skills2Play (blue cards) and Skills2PlaySport (purple cards) supplied to primary school deliverers by the Youth Sport Trust. Skills2Play is targeted at Key Stage 1 (KS1) and focuses on generic skill development through a range of play activities that focus on stability, object control and locomotion. Skills2PlaySport is targeted at lower Key Stage 2 (KS2) and includes multiskill activities that build from the generic skills but also introduce the connectivity with the sports through the development of skills specific to sporting ‘themes’, namely ‘Invasion’, ‘Striking and Fielding’ and ‘Net/Wall’. Further themes are currently at varying stages of development and include ‘Aquatics’, ‘Gymnastics’, ‘Athletics’ and ‘Wheels’. ABOUT THE EVALUATION The Centre for Sport, Physical Education & Activity Research (SPEAR) was commissioned by the Youth Sport Trust to conduct an independent evaluation of the Skills2Play/Sport programme between January 2014 and July 2015. The initial stages of the evaluation focused on the pilot programme undertaken in fifty primary schools. In May 2014 SPEAR produced the Pilot Evaluation Report, which captured teachers’ experiences of the training, resources and delivery of the Skills2Play/Sport pilot programme. The programme was then rolled out to 1,000 schools nationally and the objectives of the Evaluation of the national Skills2Play/Sport programme were as follows: 1. To assess how Skills2PlaySport and Skills2Play are being delivered and sustained in primary schools to support children’s physical literacy development. 2. To investigate the impact of Skills2PlaySport on the development of lower Key Stage 2 children’s physical literacy over 12 weeks of the programme. 3. To investigate the impact of Skills2Play on the development of Key Stage 1 children’s physical literacy over 12 weeks of the programme

    Calcareous nannofossil assemblage changes across the Paleocene–Eocene Thermal Maximum: Evidence from a shelf setting

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    Biotic response of calcareous nannoplankton to abrupt warming across the Paleocene/Eocene boundary reflects a primary response to climatically induced parameters including increased continental runoff of freshwater, global acidification of seawater, high sedimentation rates, and calcareous nannoplankton assemblage turnover. We identify ecophenotypic nannofossil species adapted to low pH conditions (Discoaster anartios, D. araneus, Rhomboaster spp.), excursion taxa adapted to the extremely warm climatic conditions (Bomolithus supremus and Coccolithus bownii), three species of the genus Toweius (T. serotinus, T. callosus, T. occultatus) adapted to warm, rather than cool, water conditions, opportunists adapted to high productivity conditions (Coronocyclus bramlettei, Neochiastozygus junctus), and species adapted to oligotropic and/or cool‐water conditions that went into refugium during the PETM (Zygrablithus bijugatus, Calcidiscus? parvicrucis and Chiasmolithus bidens). Discoaster anartios was adapted to meso- to eutrophic, rather than oligotrophic, conditions. Comparison of these data to previous work on sediments deposited on shelf settings suggests that local conditions such as high precipitation rates and possible increase in major storms such as hurricanes resulted in increased continental runoff and high sedimentation rates that affected assemblage response to the PETM

    Emplacement characteristics, time scales, and volcanic gas release rates of continental flood basalt eruptions on Earth

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    Continental flood basalt provinces are the subaerial expression of large igneous province volcanism. The emplacement of a continental flood basalt is an exceptional volcanic event in the geological history of our planet with the potential to directly impact Earth's atmosphere and environment. Large igneous province volcanism appears to have occurred episodically every 10–30 m.y. through most of Earth history. Most continental flood basalt provinces appear to have formed within 1–3 m.y., and within this period, one or more pulses of great magma production and lava eruption took place. These pulses may have lasted from 1 m.y. to as little as a few hundred thousand years. Within these pulses, tens to hundreds of volumetrically large eruptions took place, each producing 103-104 km3 of predominantly pahoehoe lava and releasing unprecedented amounts of volcanic gases and ash into the atmosphere. The majority of magmatic gas species released had the potential to alter climate and/or atmospheric composition, in particular during violent explosive phases at the eruptive vents when volcanic gases were lofted into the stratosphere. Aside from the direct release of magmatic gases, magma-sediment interactions featured in some continental flood basalt provinces could have released additional carbon, sulfur, and halogen-bearing species into the atmosphere. Despite their potential importance, given the different nature of the country rock associated with each continental flood basalt province, it is difficult to make generalizations about these emissions from one province to another. The coincidence of continental flood basalt volcanism with periods of major biotic change is well substantiated, but the actual mechanisms by which the volcanic gases might have perturbed the environment to this extent are currently not well understood, and have been little studied by means of atmospheric modeling. We summarize current, albeit rudimentary, knowledge of continental flood basalt eruption source and emplacement characteristics to define a set of eruption source parameters in terms of magmatic gases that could be used as inputs for Earth system modeling studies. We identify our limited knowledge of the number and length of non-eruptive phases (hiatuses) during continental flood basalt volcanism as a key unknown parameter critical for better constraining the severity and duration of any potential environmental effects caused by continental flood basalt eruptions

    Quantum Delocalized Interactions

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    Classical mechanics obeys the intuitive logic that a physical event happens at a definite spatial point. Entanglement, however, breaks this logic by enabling interactions without a specific location. In this work we study these delocalized interactions. These are quantum interactions that create less locational information than would be possible classically, as captured by the disturbance induced on some spatial superposition state. We introduce quantum games to capture the effect and demonstrate a direct operational use for quantum concurrence in that it bounds the nonclassical performance gain. We also find a connection with quantum teleportation, and demonstrate the games using an IBM quantum processor

    Popular music, psychogeography, place identity and tourism: The case of Sheffield

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    Tourism and cultural agencies in some English provincial cities are promoting their popular music ‘heritage’ and, in some cases, contemporary musicians through the packaging of trails, sites, ‘iconic’ venues and festivals. This article focuses on Sheffield, a ‘post-industrial’ northern English city which is drawing on its associations with musicians past and present in seeking to attract tourists. This article is based on interviews with, among others, recording artists, promoters, producers and venue managers, along with reflective observational and documentary data. Theoretical remarks are made on the representations of popular musicians through cultural tourism strategies, programmes and products and also on the ways in which musicians convey a ‘psychogeographical’ sense of place in the ‘soundscape’ of the city
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