1,561 research outputs found

    Cruise Report: CD149 – RRS Charles Darwin 18th July to 6th August, 2003. Spreading-ridge geometry, hydrothermal activity, and the influence of modern and ancient hotspots on the Carlsberg Ridge - northwestern Indian Ocean

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    Cruise CD149 on board the RRS Charles Darwin aimed to explore the Carlsberg Ridge, Northern Indian Ocean. The cruise recovered multibeam swath bathymetry (EM12), dredge samples from 20 stations, water column profiles from 16 stations and water samples from one station, between 57 and 61.5°E. The initial results were: a discovery of a hydrothermal super plume – a plume signal rising 1200m above the seafloor and extending 30km along the ridge crest (named by the ship’s company as the iGass Plume); recovery of an extinct hydrothermal site with oxidised sulphide chimney fragments; imagery of a megamullion site with recovery of dolerite, flazer gabbro and moderately fresh peridotite from a core complex of lower crust and upper mantle; and fresh basaltic glass samples from 95% of the sites sampled.Until this cruise, the western Carlsberg Ridge was almost unknown, with only two or three poorly located rock samples, no continuous bathymetry, only a few single-track geophysics lines and no exploration for hydrothermal activity. However, the ridge is important since it probably includes the unradiogenic end-member of the Indian Ocean mantle source (at its eastern end), is likely to have a distal influence from the Afar hotspot (at its western end), and has a history of recent changes in spreading geometry reflected in an unusual segmentation pattern. It also represents a distal portion of the midocean ridge system that is connected through its eastern end only, thus having significant implications for the dispersal and colonisation of hydrothermal ecosystems

    Cruise Report: CD149 – RRS Charles Darwin 18th July to 6th August, 2003. Spreading-ridge geometry, hydrothermal activity, and the influence of modern and ancient hotspots on the Carlsberg Ridge - northwestern Indian Ocean

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    Cruise CD149 on board the RRS Charles Darwin aimed to explore the Carlsberg Ridge, Northern Indian Ocean. The cruise recovered multibeam swath bathymetry (EM12), dredge samples from 20 stations, water column profiles from 16 stations and water samples from one station, between 57 and 61.5°E. The initial results were: a discovery of a hydrothermal super plume – a plume signal rising 1200m above the seafloor and extending 30km along the ridge crest (named by the ship’s company as the iGass Plume); recovery of an extinct hydrothermal site with oxidised sulphide chimney fragments; imagery of a megamullion site with recovery of dolerite, flazer gabbro and moderately fresh peridotite from a core complex of lower crust and upper mantle; and fresh basaltic glass samples from 95% of the sites sampled.Until this cruise, the western Carlsberg Ridge was almost unknown, with only two or three poorly located rock samples, no continuous bathymetry, only a few single-track geophysics lines and no exploration for hydrothermal activity. However, the ridge is important since it probably includes the unradiogenic end-member of the Indian Ocean mantle source (at its eastern end), is likely to have a distal influence from the Afar hotspot (at its western end), and has a history of recent changes in spreading geometry reflected in an unusual segmentation pattern. It also represents a distal portion of the midocean ridge system that is connected through its eastern end only, thus having significant implications for the dispersal and colonisation of hydrothermal ecosystems

    On the Moduli Space of SU(3) Seiberg-Witten Theory with Matter

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    We present a qualitative model of the Coulomb branch of the moduli space of low-energy effective N=2 SQCD with gauge group SU(3) and up to five flavours of massive matter. Overall, away from double cores, we find a situation broadly similar to the case with no matter, but with additional complexity due to the proliferation of extra BPS states. We also include a revised version of the pure SU(3) model which can accommodate just the orthodox weak coupling spectrum.Comment: 32 pages, 25 figures, uses JHEP.cls, added references, deleted joke

    Dynamic insulation in multistorey buildings.

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    Dynamic insulation permits the movement of air and moisture through the external walls of a building to reduce heat loss and achieve high indoor air quality. The present paper details a pilot study carried out to examine the influence of fire safety requirements and external wind on the performance of naturally ventilated multistorey buildings in which the external envelope is dynamically insulated. The theoretical foundation is outlined for a spreadsheet model used to simulate prototype 3-, 4-, 5- and 10-storey buildings all sharing the same rectangular floor plan, with fresh air drawn into the building through the envelope by depressurisation using a fan-driven, ducted extract system. From the analysis, the effects of wall porosity, depressurisation level, extract system deployment, occupant density and distribution, and building orientation have been quantified, confirming the practical feasibility of such a system

    Educational Procedures In This Development Of Agricultural Cooperatives At The Sabine Farms, Harrison County, Texas

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    Purposes of the Study The purposes of this study are, first, to determine the educational procedures involved in the organization of the Sabine Farms Agricultural Cooperatives, and second, to present certain facts that may be applied to similar situations in other communities where there is a possibility of the organization of agricultural cooperatives through educational procedures in such channels as creating desires on the part of farmers to work cooperatively for increased economic, social, and educational advantages. It Is hoped that professional agricultural leaders, as well as laymen, will find this information practical and helpful. Statement of the Problem Under the present economic conditions in America, it is a fundamental principle that successful business organization among farmers must be founded for those enterprises engaged in by the farmers. Up to the present time, it has not been a general, but rather, it has been a rare practice for the average or small farmers to organize themselves for business purposes. One cannot say why this laxity exists the rarity of the organization of farmers for economic purposes. Whether the farmers are lazy, lack information as to the importance of such organizations, or whether the farmers do not have the necessary guiding forces in the form of information or individuals cannot be determined. At any rate, the problem exists. A solution for this problem is gravely needed. Scope. Sources, and Methods of Obtaining Data In this paper, the writer is concerned with the Sabine Farms Cooperatives only. The materials used in compiling this work were obtained from the W. R, Banks Library, Consumers Cooperative Association, Cooperative League of the United States of America, Cooperative Publishers Association, the Organization and Cooperative Marketing Specialist of the Texas Agricultural and Mechanical College Extension Service, National Cooperative Incorporated, and numerous inquiry forms carried to the Supervisor of the Sabine Farms and to the Manager of the Sabine Farms Agricultural Cooperatives

    Environmental design using dynamic insulation.

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    In conventional airtight buildings, the architect has considerable freedom to decide how much the external environment will influence the internal heating, cooling, and ventilation loads. The services engineer provides the plant and equipment required to deal with these loads. This division of labor could lead to undesirable consequences in the case of dynamic insulation, a form of air permeable construction where bulk air flow through the building envelope may be used to either enhance or restrict the conductive heat and mass diffusion fluxes. Small changes in temperature (indoor and out) and wind speed and direction will influence the behavior of a dynamically insulated envelope since the internal and external environments are much more intimately coupled. Buildings employing dynamic insulation thus require good environmental design principles to be applied. The objective of this paper is to lay down rigorous principles that will form the basis of guidelines to architects and building services engineers on how to take account of the ever changing external environment when designing durable and comfortable buildings employing dynamic insulation

    Study of the Local Interstellar Medium using Pulsar Scintillation

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    We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the local interstellar medium (LISM). Our analysis reveals several anomalies in the scattering strength, which suggest that the distribution of scattering material in the Solar neighborhood is not uniform. Our model suggests the presence of a low density bubble surrounded by a shell of much higher density fluctuations. We are able to put some constraints on geometrical and scattering properties of such a structure, and find it to be morphologically similar to the Local Bubble known from other studies.Comment: 5 pages, 3 figure

    The use of dynamic and diffusive insulation for combined heat recovery and ventilation in buildings.

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    Modern buildings, domestic and commercial, have attempted to reduce their energy requirements by improving the airtightness of the envelope and increasing the thickness of insulation. However, this trend has developed simultaneously with increased use of synthetic materials in construction, furnishings and decorations, which give off volatile organic compounds, and increasing living standards which result in higher indoor temperature and moisture generation rates within homes. The result has been a reduction in indoor air quality which directly affects occupant health and increasing problems of dampness in homes, particularly for the poor

    Origami lesion-targeting device for CT-guided interventions

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    The objective of this study is to preliminarily evaluate a lesion-targeting device for CT-guided interventions. The device is created by laser cutting the structure from a sheet of medical grade paperboard, 3D printing two radiocontrast agent grids onto the surface and folding the structure into a rectangular prism with a viewing window. An abdominal imaging phantom was used to evaluate the device through CT imaging and the targeting of lesions for needle insertion. The lesion-targeting trials resulted in a mean targeting error of 2.53 mm (SD 0.59 mm, n = 30). The device is rigid enough to adequately support standard biopsy needles, and it attaches to the patient, reducing the risk of tissue laceration by needles held rigidly in place by an external manipulator. Additional advantages include adequate support for the insertion of multiple surgical tools at once for procedures such as composite ablation and the potential to guide off-axial needle insertion. The low-cost and disposability of the device make it well-suited for the minimally invasive image-guided therapy environment
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