95 research outputs found

    Performance Indicators in Club Level Gaelic Football

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    Over 2000 Gaelic Football clubs compete annually for the honour of playing in the All-Ireland club finals in Croke Park in front of up to 30,000 people. There are no published performance data for club level Gaelic football, despite evidence of considerable performance analysis activity. This study aims to establish benchmark profiles for Senior, Intermediate and Junior grade club Gaelic football and investigate which variables are most closely associated with winning. Data from all tiers of the Ulster club football championship of 2015 and 2016 (n = 48) were analysed using a range of validated operational definitions measuring 17 variables. Differences between winning and losing performance were tested using a Mann-Whitney U test. Across all grades, six variables proved significant (p \u3c 0.05), three were directly related to scoring (points, number of scores and total score), the others related to the effective use of possession (possession: scores ratio; turnover rate and productivity (scores per possession)). Several others are specific to certain grades, and are directly linked to successful performance at that level

    A Novel TiO2 / PVC Layer for Use in a Photoelectrochemical Cell

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    A novel method of coating titanium dioxide on a glassy carbon electrode as a polyvinylchloride composite , is described. On illumination , there is an enhanced voltammetric current at this TiO2/PVC composite in aqueous formic acid solution. This electrode is used as the basis of a formic acid fuel cell where oxygen is reduced at a platinum cathode. The system yields 100 cm-2 for 0.01 mol dm-3 HCOOH in 0.1 mol dm-3 NaOH under illumination from a 150 W xenon lamp. The current without illumination is 0.5 cm-2

    Solar disinfection of drinking water in the developing world, photoluminescence analysis of point defects in crystalline silicon and acoustic analysis of the human voice: A physicist’s journey in foreign lands.

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    The following publications are a chronological account of my research career spanning the past three decades. The body of work is divided into three broad categories corresponding to: (i) Solid State Physics, (ii) Point-of-Use Water Treatment and (iii) Other Fields of Research. Each category has brought its own reward

    Luminescence studies of transition metal related defects in crystalline silicon

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    Infra-red photoluminescence (PL) spectra of zinc and copper related defects in silicon are presented in this thesis. Seven new PL systems with principal zero phonon lines at 919.8, 943.67, 945.8, 1033.5, 1059.9, 1090.7 and 1129.8 meV are discussed. All of the spectra can be classified as being due to isoelectronic bound exciton ( IBE ) recombination. Although the identities of the binding centres have not been conclusively established clear evidence has been obtained in most cases for the involvement of at least one specific transition metal ( TM ) impurity element. The PL systems at 945.8, 919.8 and 1059.9 meV are all observed in silicon diffused with zinc and another TM. The 945.8 meV system is observed in silicon diffused with zinc at 1100° C for 16 hours. The system is not created by interstitial Mn and substitutional Zn as previously suggested. The 919 meV system is observed in silicon co-diffused with zinc and copper at 1100° C for 16 hours, while the 1059.9 meV system is most clearly observed in SisFeZn quenched from 1000° C. For silicon implanted with zinc the 1129.8 and 1090.7 meV systems are observed. Both of these systems have ground state and excited state splittings placing them in a minority group of IBE centres in silicon associated with deep acceptors and including the indium and thallium systems. The quenching rate is found to be crucial for samples diffused with copper only. Slow quenches produce the 1034 meV SK system. Zeeman studies on the zero phonon lines of this centre reveal a singlet - triplet nature indicative of a strong central cell potential about the defect as well as a strong crystal field reaction. Rapid quenches combined with * low copper concentrations produces the 943.7 Cu PL system. Uniaxial stress and magnetic field measurements on this centre suggest that the two lowest energy transitions arise from bound exciton recombination at a defect with tetrahedral or near tetrahedral symmetry. Diffusion rate calculations show that a single interstitial copper atom is not the most likely configuration . A larger defect involving one or more atoms in a Td arrangement is more likely, perhaps similar to to those already reported for the Mn4 and Li^ defects in PL and for the NL22 Fe related centre in EPR. It is concluded that diffusion is not a suitable method of introducing transition metal impurities into silicon since the process is extremely susceptible to contamination. Implantation of the desired element followed by rapid thermal annealing is suggested as a much more promising avenue of investigation since this method affords much more control over the concentration, implantation depth and most importantly of all, the identity of the chemical element introduced into the host crystal

    Can solar water-treatment really help in the fight against water shortages?

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    In the face of increasing global population, rising industrialization and the inescapable reality of climate change, the demand for access to clean, safe water has never been greater. Solar wastewater remediation technologies and solar water-treatment have the potential to contribute significantly towards affordable and sustainable solutions to this seemingly intractable problem. They do this by using solar energy to treat water from sources that previously would have been considered unsuitable for further use. In this article we reveal the basic principles surrounding the design and application of solar remediation reactors for urban wastewater treatment and reuse and then show how even simpler technologies are being used in low-income communities to provide affordable and safe potable water

    Agility demands of Gaelic football match-play: a time-motion analysis

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    Research into the physical demands of Gaelic football is limited with no research into the agility or change of direction (CoD) demands of the sport. This study examined the CoD demands of Gaelic football via a time-motion analysis of senior inter-county match play. The Bloomfield movement classification (BMC) was adapted for application to Gaelic football. A new “descriptor” was used in an effort to account for the decision-making component of agility by isolating actions that occurred during active engagement with play. Of 1,899 changes of direction (CoDs) identified, 1,035 occurred during active engagement in play. The left/right split for CoDs during active engagement in play was 47.1/49.9%, indicating no preference for completing actions to one side over the other. Whilst the most common CoDs were ≀90° (74.9%), 80% of CoDs greater than 270° took place during active engagement in play. CoD actions are very common in Gaelic football and may be more common than in other field and court sports. It is important that athletes are physically prepared to cope with the demands of very acute CoDs during meaningful periods of match play

    Remote Predictive Mapping 7. The Use of Topographic–Bathymetric Lidar to Enhance Geological Structural Mapping in Maritime Canada

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    An airborne topo-bathymetric lidar survey was conducted at Cape John, on the north shore of Nova Scotia, Canada, using the shallow water Leica AHAB Chiroptera II sensor. The survey revealed new bedrock features that were not discovered using previous mapping methods. A thick blanket of glacial till covers the bedrock on land, and outcrops are exposed only along the coastal cliffs and offshore reefs. The seamless landseabed digital elevation model produced from the lidar survey revealed significant bedrock outcrop offshore where ocean currents have removed the glacial till, a significant finding that was hitherto hidden under the sea surface. Several reefs were identified offshore as well as a major fold structure where block faulting occurs along the limbs of the fold. The extension of the Malagash Mine Fault located ~10 km west of Cape John is proposed to explain the local folding and faulting visible in the submerged outcrops. The extension of this fault is partially visible on land, where it is obscured by glacial till, and its presence is supported by the orientation of submerged bedding and lineaments on both the south and north sides of Cape John. This paper demonstrates how near-shore high-resolution topography from bathymetric lidar can be used to enhance and refine geological mapping.RÉSUMÉUn levĂ© lidar topo-bathymĂ©trique Ă©tĂ© rĂ©alisĂ© Ă  Cape John, sur la rive nord de la Nouvelle-Écosse, Canada, en utilisant un capteur Leci AHAB Chiroptera II. Ce levĂ© a permis de repĂ©rer des affleurements que les mĂ©thodes de cartographie plus anciennes n’avaient pu dĂ©tecter. Une Ă©paisse couche de till glaciaire recouvre la roche en place sur le continent, et la roche affleure seulement le long des falaises cĂŽtiĂšres et des rĂ©cifs cĂŽtiers. Le modĂšle numĂ©rique de dĂ©nivelĂ© en continu terres et fonds marins obtenu par le levĂ© lidar a rĂ©vĂ©lĂ© l’existence d’affleurement rocheux considĂ©rables au large des cĂŽtes, lĂ  oĂč les courants ocĂ©aniques ont emportĂ© le till glaciaire, une dĂ©couverte importante demeurĂ©e cachĂ©e sous la surface de la mer jusqu’alors. Plusieurs rĂ©cifs ont Ă©tĂ© identifiĂ©s au large des cĂŽtes, ainsi qu’une structure de pli majeure, Ă  l’endroit oĂč se produit un morcellement en blocs le long des flancs du pli. Une extension de la faille de la mine Malagash situĂ© ~ 10 km Ă  l’ouest de Cape John est proposĂ© pour expliquer les plis et les failles locaux visibles dans les affleurements submergĂ©s. L’extension de cette faille est partiellement visible sur la terre, voilĂ©e par le till, et sa prĂ©sence est Ă©tayĂ©e par l’orientation de la stratification et des linĂ©aments submergĂ©s tant du cĂŽtĂ© sud que nord de Cape John. Cet article montre comment la topographie haute rĂ©solution du lidar bathymĂ©trique peut ĂȘtre utilisĂ©e pour amĂ©liorer et affiner la cartographie gĂ©ologique

    Evaluation of Solar Disinfection of E. coli Under Sub-Saharan Field Conditions Using a 25 Litre Borosilicate Glass Batch Reactor Fitted with a Compound Parabolic Collector.

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    The bacterial inactivation efficacy of a solar water disinfection (SODIS) reactor consisting of a 25L borosilicate glass tube fitted with a compound parabolic collector (BGTR-CPC) was assessed under equatorial weather conditions in Uganda. The SODIS BGTR-CPC was tested over a 17-month period in Sub-Saharan conditions in Kampala, Uganda. The BGTR-CPC was filled with natural water from a nearby protected well. A wild strain of Escherichia coli isolated from local natural water was added to the reactor to give a starting population of between 105 and 107 CFU/100ml. This spiked water was exposed to natural sunlight. Satisfactory bacterial inactivation (log10 reduction values \u3e6 units or inactivation to below the limit of detection (/100ml.)) was observed for 11 of 13 experiments. Rainfall and overcast/cloudy conditions were factors on both of the occasions when incomplete inactivation was observed. In conclusion, the use of CPC SODIS technology is suitable for treating drinking water both at household level and institutional level in Sub-Saharan and other similar tropical climates if careful consideration of the cloud cover and rainfall is taken into account

    Nitrogen and Copper doped solar light active TiO2 photocatalyst for water decontamination

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    A novel class of photocatalytic coating capable of degrading bacterial and chemical contaminants in the presence of visible sunlight wavelengths was produced by depositing a stable photocatalytic TiO2 film on the internal lumen of glass bottles via a sol gel method. This coating was prepared in either undoped form or doped with nitrogen and/or copper to produce visible light-active TiO2 films which were annealed at 600 °C and were characterized by Raman, UV-Vis, and X-ray photoelectron spectroscopy. The presence of doped and undoped TiO2 films was found to accelerate the degradation of methylene blue in the presence of natural sunlight, while copper-doped TiO2 films were found to accelerate bacterial inactivation (of E. coli and E. faecalis) in the presence of natural sunlight

    Solar photocatalysis for water disinfection: Materials and reactor design

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    As of 2010, access to clean drinking water is a human right according to UN regulations. Nevertheless, the number of people living in areas without safe drinking water is predicted to increase by three billion by the end of this decade. Several recent cases of E. coli and Cryptosporidium contamination in drinking water are also reported in a number of advanced countries. Therefore ensuring the potability of drinking water is urgent, but highly challenging to both the developing and developed world in the future. A combination of solar disinfection and photocatalysis technology offers real possibilities for removing lethal pathogenic microroganisms from drinking water. The time taken for the conventional SODIS process can be greatly reduced by semiconductor (e.g. TiO2, ZnO, nano-heterojunctions) based photocatalysis. This review addresses the fundamental reaction mechanism, advances in materials synthesis and selection and recent developments in the reactor design for solar energy driven photocatalysis using titanium dioxide. The major advantage of using photo-reactors is that they enhance disinfection by increasing photon flux into the photocatalyst. Other major factors affecting such efficiency of solar-based photocatalysis such as the illuminated volume/total volume ratio, catalyst load and flow rate, are discussed in detail. The significance of using immobilised catalysts over the catalyst powder in slurries is also highlighted. It is noted that, despite encouraging early field studies, the commercialisation and mass production of solar photocatalysis systems remains highly challenging. Recommendations for future directions for addressing issues such as mass transfer, requirement of a standard test method, photo-reactors design and visible light absorption by TiO2 coatings are also discussed
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