197,396 research outputs found
Validation and verification of hull resistance components using a commercial CFD code
No full textA mathematically defined Wigley hull form is used to investigate the application of a commercial CFD code in prediction of the total resistance and its components from tangential and normal forces on the hull wetted surface. The computed resistance and wave profiles alongside the hull were compared with experimental observations for six different Froude numbers to validate the simulations. The effects of grids, domain size and turbulence models were studied. A statistical hypothesis test was carried on these resistance data in order to determine the most suitable turbulence model for the lowest and highest Froude numbers
Mechanisms for accumulation and migration of technetium-99 in saltmarsh sediments
No full textThis thesis describes the development of analytical methods for both the bulk determination of 99Tc, and determination of 99Tc in sequential extracts from sediments. These methods have been used to collect data, which, along with trace and major element data have been used to interpret the mechanisms for 99Tc input, migration and accumulation in saltmarshes. The inventory of 99Tc stored in the Thornflatt Saltmarsh, Esk Estuary has also been determined. The routine determination of 99Tc in bulk samples uses 99mTc as a yield monitor. Samples are ignited stepwise to 550°C and the 99Tc is extracted using 8M nitric acid. Many contaminants are precipitated with Fe(OH)3 and the Tc in the supernant is pre-concentrated and further purified using anion-exchange chromatography. Final separation of Tc from Ru is achieved by extraction of Tc into 5% TnOA in xylene from 2M sulphuric acid. The yield is determined by γ-spectrometric analysis of 99mTc. Determination of 99Tc is made by liquid scintillation counting. Typical recoveries are in the order of 70-95% and the method has a detection limit of 1.7 Bq/kg for a sample size of 10g. Determination of Tc in sequential extracts uses operationally defined procedures to extract: exchangeable Tc, reducible Tc and oxidisable Tc. An initial water wash is used to extract any occluded Tc and a final leach in 8 M nitric acid is used to dissolve any residual Tc. The isolation of 99Tc uses TEVA resin for Extracts 1-4 and the decontamination procedure developed for bulk analysis for Extract 5. 99mTc was used as a yield monitor, and determination of 99Tc is by liquid scintillation counting. Limits of detection were dependent on the amount of 99mTc tracer used but were found to be as low as 2.4 Bq/kg for a sample size of 2g. A study was made of the mechanisms responsible for the accumulation and migration of Tc in estuarine sediments using sediments collected from saltmarshes at Thornflatt, Carlaverock and the Ribble Estuary. 99Tc was present at determinable activities in all the sediment cores taken from these sites. Good correlations between Tc and CaO as well as CO3 concentrations and poor correlation between Tc and radionuclides adsorbed to inorganic detritus infer a direct input of 99Tc to marsh sediments. Determination of 99Tc in biota living on the marsh also showed that this was not a significant pathway for input of Tc to the sediments. Sequential extraction data imply sorption to an organic fraction of the sediment. Stable element and sequential extraction data indicates that Tc is readily oxidised and remobilised before reprecipitation where redox conditions are favourable. Data indicate a reduction potential between those of the MnIV to MnII reaction and the FeIII to FeII reaction is necessary for re-accumulation to occur, as suggested by published thermodynamic data. Data collected from reducing sediments imply that similar mechanisms are responsible for the accumulation of Mn (e.g. reduction by sulphate reducing bacteria) and the accumulation of Tc. The inventory of 99Tc held within the Thornflatt saltmarsh is proportionally less than that of 137Cs or 241Am when compared to discharges from Sellafield. However a higher proportion of 99Tc is transferred from Seliafield and incorporated into saltmarsh sediments than is suggested by previously published standard distribution coefficient data. Saltmarsh sediments are therefore a more important sink of 99Tc than extrapolations made from inventories of other radionuclides would suggest
Molly Asthore valse [music] /
No full textFor piano.; Cover title.; "Founded on M. Lavenu's favourite ballads. Composed expressly for Her Majesty's birthday ball held at Governemnt House, Sydney, May 25th 1858, and most respectfully inscribed to Lady Denison".; Cover illustration of young woman.; Lithographer: Allan & Wigley.; Publication date from G. Skinner (2011), 'Toward a general history of Australian musical composition: first national music, 1788-c.1860', Sydney Conservatorium of Music, p. 538 http://trove.nla.gov.au/work/81022028; Published in: Australian music.; Also available online http://nla.gov.au/nla.mus-an5397123
La policía de la moda
No full textSe presenta en castellano el texto del profesor Wigley que originalmente constituye el segundo capítulo de su conocido White
Walls, Designer Dresses. The Fashioning of Modern Architecture. El texto profundiza con brillantez en la compleja relación entre
moda y arquitectura moderna. Parte de la convicción de que "el discurso contemporáneo sobre la arquitectura continúa organizado
alrededor de los continuos ataques a la moda". Para mostrar esta realidad repasa la actitud defensiva y en ocasiones de
"perro guardian" de algunos de sus principales representantes teóricos: desde Le Corbusier y sus escritos sobre las paredes
blancas, hasta Giedion, cuya posición es rastreada con minuciosidad a lo largo de sus principales escritos, hasta Tafuri, que en
su influyente Teoría e Historia de la Arquitectura presenta una similar actitud hacia la moda. Wigley concluye mostrando cómo
estos rechazos de la moda son en definitiva una prueba de su vigencia como disciplina y explica que, en consecuencia, "ningún
discurso puede aislarse de la moda sin más"
Book review. Helping Children to Build Self-Esteem, Deborah M. Plummer, Jessica Kingsley 2007, ISBN: 978-1-84310-488-9, £19.99
No full textLa nueva pintura del emperador
No full textEl texto repasa la conocida "Ley de Ripolin" que Le Corbusier expone en su famoso texto L'art décoratif d'aujourd'hui, en el que
el arquitecto suizo aspira a encontrar respuesta a la pregunta fundamental: ¿dónde está la arquitectura? A partir de una brillante
reflexión sobre el papel de las paredes blancas en la arquitectura moderna, Wigley rescata el carácter textil y en consecuencia
"superficial" de la condición moderna de la arquitectura. De este modo se muestra cómo la arquitectura de Le Corbusier enlaza
con los argumentos de Loos y Semper, y más aun se ve con claridad la auténtica condición de la arquitectura como fenómeno
visual que a su vez se localiza en el espacio de la comunicación. Como Wigley apunta, es necesario explorar con mucho detalle
la fina capa blanca y para eso es preciso ahondar con mucha más profundidad en la superficie
Plan of highly valuable allotments, railway station Liverpool [cartographic material] /
No full textCadastral map of Liverpool, showing groundplan of Drummond House.; Maps 338 and 637 from Ferguson Collection.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-f338
Morphological and physiological interactions of NG2-glia with astrocytes and neurons
No full textModels of central nervous system (CNS) function have historically been based on neurons and their synaptic contacts - the neuronal doctrine. This doctrine envisages glia as passive supportive cells. However, electrophysiological and imaging studies in brain slices show us that astrocytes, the most numerous cells in the brain, express a wide range of neurotransmitter receptors that are activated in response to synaptic activity. Furthermore, astrocytes communicate via calcium signals that are propagated over long distances by the release of 'gliotransmitters', the most abundant being adenosine triphosphate (ATP). This has led to the concept of the neuron-astroglial functional unit as the substrate of integration in the CNS. Recently, a novel glial cell type has been characterized by expression of the proteoglycan NG2. These NG2-glia receive presynaptic input from neurons and responds to neurotransmitters released at synapses. Now, studies on transgenic mice in which fluorescent proteins are specifically expressed by subclasses of glia are helping to address the question of where NG2-glia fit in the neuron-astroglial model of integrated brain function. NG2-glia, as well as astrocytes, have been shown to respond to neuronal and astroglial signals by raised intracellular calcium, which is a potential communications mechanism by which NG2-glia may be active partners in neuron-glial circuits. Moreover, a current concept of NG2-glia considers them to be 'neural stem cells' and an exciting prospect is that neuron-glial signalling may regulate the differentiation capacity of NG2-glia and their response to injury.</p
Molly Asthore valse [music] /
No full textFor piano.; Cover title.; Engraved.; "Founded on M. Lavenu's favorite ballad. Composed expressly for Her Majesty's birthday ball held at Government House, Sydney, May 25th 1858 and most respectfully inscribed to Lady Denison".; Lithographer: Allan & Wigley.; Publication date from G. Skinner (2011), 'Toward a general history of Australian musical composition: first national music, 1788-c.1860', Sydney Conservatorium of Music, p. 538 http://trove.nla.gov.au/work/81022028; Also available online http://nla.gov.au/nla.mus-an6397834
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