1,676 research outputs found

    Geostatistical analysis of an experimental stratigraphy

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    [1] A high-resolution stratigraphic image of a flume-generated deposit was scaled up to sedimentary basin dimensions where a natural log hydraulic conductivity (ln( K)) was assigned to each pixel on the basis of gray scale and conductivity end-members. The synthetic ln( K) map has mean, variance, and frequency distributions that are comparable to a natural alluvial fan deposit. A geostatistical analysis was conducted on selected regions of this map containing fluvial, fluvial/ floodplain, shoreline, turbidite, and deepwater sedimentary facies. Experimental ln(K) variograms were computed along the major and minor statistical axes and horizontal and vertical coordinate axes. Exponential and power law variogram models were fit to obtain an integral scale and Hausdorff measure, respectively. We conclude that the shape of the experimental variogram depends on the problem size in relation to the size of the local-scale heterogeneity. At a given problem scale, multilevel correlation structure is a result of constructing variogram with data pairs of mixed facies types. In multiscale sedimentary systems, stationary correlation structure may occur at separate scales, each corresponding to a particular hierarchy; the integral scale fitted thus becomes dependent on the problem size. The Hausdorff measure obtained has a range comparable to natural geological deposits. It increases from nonstratified to stratified deposits with an approximate cutoff of 0.15. It also increases as the number of facies incorporated in a problem increases. This implies that fractal characteristic of sedimentary rocks is both depositional process - dependent and problem-scale-dependent

    HTC Scientific Computing in a Distributed Cloud Environment

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    This paper describes the use of a distributed cloud computing system for high-throughput computing (HTC) scientific applications. The distributed cloud computing system is composed of a number of separate Infrastructure-as-a-Service (IaaS) clouds that are utilized in a unified infrastructure. The distributed cloud has been in production-quality operation for two years with approximately 500,000 completed jobs where a typical workload has 500 simultaneous embarrassingly-parallel jobs that run for approximately 12 hours. We review the design and implementation of the system which is based on pre-existing components and a number of custom components. We discuss the operation of the system, and describe our plans for the expansion to more sites and increased computing capacity

    Ensayo de una metodología innovadora para la detección de masas polimetálicas profundas: modelo geológico y exploración geotérmica preliminares de la Masa Valverde (Huelva).

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    Se presentan los resultados provisionales de los trabajos iniciales realizados para el Proyecto Innovative Geothermal Methodology to detect deep blind Polymetallic Ore Bodies, financiado por la CE Y co-financiado por DGICYT y organizaciones participantes. Los principales objetivos de este Proyecto son la cuantificación de los efectos térmicos "in situ" de masas polimetálicas profundas a fin de desarrollar nuevos métodos geotérmicos específicos que puedan detectar depósitos no aflorantes. Dichos métodos deberían proporcionar, previsiblemente, un procedimiento rápido y barato para la detección superficial de cuerpos profundos, midiendo perfiles térmicos en sondeos cortos. La exploración geotérmica permite, a diferencia de otros métodos (por ejemplo gravimetría), discriminar anomalías significativas. Para detectar pequeñas anomalías de temperatura (teniendo en cuenta que el efecto térmico decrece rápidamente hacia la superficie), la resolución térmica medida debe ser del orden de O,001ºC. Se han calibrado nuevos termistores muy sensibles en el Laboratoire National d'Essais (LNE) de París para obtener la máxima sensibilidad en el intervalo de temperaturas considerado (lO a 60ºC). Se miden conductividades térmicas sobre testigos con una precisión del 5% y una reproductibilidad del 2%, que permiten determinar las anomalías del gradiente de temperatura relacionadas con las litologías. Para poner a punto el método, se modelizarán las medidas y se compararán con la realidad de cuerpos conocidos, a fin de establecer un modelo fiable y de aplicación general. Esta metodología se ensaya en primer lugar en la MV (Masa Valverde, Huelva), descubierta y reconocida mediante sondeos por la E.N. Adaro, a fin de partir de un modelo suficientemente preciso para la modelización geotérmica. Los trabajos geológicos realizados integran observaciones de campo, examen y desmuestres de testigos de sondeos, geoquímica, geología estructural y estudio de testigos por diversas técnicas como petrografía, microscopía de menas, DRX, MEB, Microsonda Electrónica, etc. A pesar de la profundidad (en torno a los 600 m.l y de la complejidad de la estructura de MV puesta de manifiesto por el presente estudio, los resultados del primer año de investigación geológica -objeto de esta comunicación-, conducen a un modelo provisional que sirve de base a la interpretación de los datos térmicos. Dicho modelo difiere de los anteriormente conocidos en aspectos como: la posición, definición e interpretación de ciertos tramos litológicos; la demostración de muy frecuentes contactos tectónicos acompañados de procesos de deformación dúctil a veces muy intensa; la identificación de fallas o cabalgamientos que definen unidades independientes, entre las cuales los tramos litológicos, incluidos los cuerpos mineralizados, no son correlaciona bies; la estructura del cuerpo mineralizado, caracterizada por una superposición de escamas imbricadas con geometría antiformal, resultado de procesos tectónicos relacionados con la Tectónica de cabalgamientos de la región y recientemente demostrados -ITGE- en la parte española de la FPI (Faja Pirítica Ibérica). Los resultados provisionales arrojan, pues, un resultado coherente desde las diversas perspectivas de trabajo, particularmente por lo que respecta a los modelos geotérmico y geológico - geométrico, y permiten albergar fundadas esperanzas en una rápida puesta a punto del método, para su aplicación en exploración

    Sparrows can't sing : East End kith and kinship in the 1960s

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    Sparrows Can’t Sing (1963) was the only feature film directed by the late and much lamented Joan Littlewood. Set and filmed in the East End, where she worked for many years, the film deserves more attention than it has hitherto received. Littlewood’s career spanned documentary (radio recordings made with Ewan MacColl in the North of England in the 1930s) to directing for the stage and the running of the Theatre Royal in London’s Stratford East, often selecting material which aroused memories in local audiences (Leach 2006: 142). Many of the actors trained in her Theatre Workshop subsequently became better known for their appearances on film and television. Littlewood herself directed hardly any material for the screen: Sparrows Can’t Sing and a 1964 series of television commercials for the British Egg Marketing Board, starring Theatre Workshop’s Avis Bunnage, were rare excursions into an area of practice which she found constraining and unamenable (Gable 1980: 32). The hybridity and singularity of Littlewood’s feature may answer, in some degree, for its subsequent neglect. However, Sparrows Can’t Sing makes a significant contribution to a group of films made in Britain in the 1960s which comment generally on changes in the urban and social fabric. It is especially worthy of consideration, I shall argue, for the use which Littlewood made of a particular community’s attitudes – sentimental and critical – to such changes and for its amalgamation of an attachment to documentary techniques (recording an aural landscape on location) with a preference for nonnaturalistic delivery in performance

    Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Data Handling Overview

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    The GLAST Balloon Flight Engineering Model (BFEM) represents one of 16 towers that constitute the Large Area Telescope (LAT), a high-energy (>20 MeV) gamma-ray pair-production telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006. The prototype tower consists of a Pb/Si pair-conversion tracker (TKR), a CsI hodoscopic calorimeter (CAL), an anti-coincidence detector (ACD) and an autonomous data acquisition system (DAQ). The self-triggering capabilities and performance of the detector elements have been previously characterized using positron, photon and hadron beams. External target scintillators were placed above the instrument to act as sources of hadronic showers. This paper provides a comprehensive description of the BFEM data-reduction process, from receipt of the flight data from telemetry through event reconstruction and background rejection cuts. The goals of the ground analysis presented here are to verify the functioning of the instrument and to validate the reconstruction software and the background-rejection scheme.Comment: 5 pages, 4 figures, to be published in IEEE Transacations on Nuclear Science, August 200
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