6,368 research outputs found

    LANDSAT Study of Alteration Aureoles in Surface Rocks Overlying Petroleum Deposits

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    The author has identified the following significant results. A series of low altitude underflight remote sensing experiments were flown at Cement and Davenport oil fields, Oklahoma. An experimental algorithm which employs a sinusoidal stretch of brightness values was developed and applied to a January 1973 scene (bands 4, 5, and 6) of Cement. The results, although not spectacular, are extremely encouraging and for the first time demonstrate that the alteration anomaly at Cement may be defined through enhanced LANDSAT images

    Redesign and cascade tests of a supercritical controlled diffusion stator blade-section

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    A supercritical stator blade section, previously tested in cascade, and characterized by a flat-roof-top suction surface Mach number distribution, has been redesigned and retested. At near design conditions, the losses and air turning were improved over the original blade by 50 percent and 7 percent respectively. The key element in the improved performance was a small blade reshaping. This produced a continuous flow acceleration over the first one-third chord of the suction surface which successfully prevented a premature laminar separation bubble. Several recently available inviscid analysis and one fully viscous (Navier-Stokes) analysis code were used in the redesign process. The validity of these codes was enhanced by the test results

    Late diagenetic indicators of buried oil and gas. 2: Direct detection experiment at Cement and Garza fields, Oklahoma and Texas, using enhanced LANDSAT 1 and 2 images

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    The author has identified the following significant results. The Cement oil field, Oklahoma, was a test site for an experiment designed to evaluate LANDSAT's capability to detect an alteration zone in surface rocks caused by hydrocarbon microseepage. Loss of iron and impregnation of sandstone by carbonate cements and replacement of gypsum by calcite were the major alteration phenomena at Cement. The bedrock alterations were partially masked by unaltered overlying beds, thick soils, and dense natural and cultivated vegetation. Interpreters, biased by detailed ground truth, were able to map the alteration zone subjectively using a magnified, filtered, and sinusoidally stretched LANDSAT composite image; other interpreters, unbiased by ground truth data, could not duplicate that interpretation

    A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)

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    We present the results of a Nobeyama 45-m water maser and ammonia survey of all 94 northern GLIMPSE Extended Green Objects (EGOs), a sample of massive young stellar objects (MYSOs) identified based on their extended 4.5 micron emission. We observed the ammonia (1,1), (2,2), and (3,3) inversion lines, and detect emission towards 97%, 63%, and 46% of our sample, respectively (median rms ~50 mK). The water maser detection rate is 68% (median rms ~0.11 Jy). The derived water maser and clump-scale gas properties are consistent with the identification of EGOs as young MYSOs. To explore the degree of variation among EGOs, we analyze subsamples defined based on MIR properties or maser associations. Water masers and warm dense gas, as indicated by emission in the higher-excitation ammonia transitions, are most frequently detected towards EGOs also associated with both Class I and II methanol masers. 95% (81%) of such EGOs are detected in water (ammonia(3,3)), compared to only 33% (7%) of EGOs without either methanol maser type. As populations, EGOs associated with Class I and/or II methanol masers have significantly higher ammonia linewidths, column densities, and kinetic temperatures than EGOs undetected in methanol maser surveys. However, we find no evidence for statistically significant differences in water maser properties (such as maser luminosity) among any EGO subsamples. Combining our data with the 1.1 mm continuum Bolocam Galactic Plane Survey, we find no correlation between isotropic water maser luminosity and clump number density. Water maser luminosity is weakly correlated with clump (gas) temperature and clump mass.Comment: Astrophysical Journal, accepted. Emulateapj, 24 pages including 24 figures, plus 9 tables (including full content of online-only tables

    Service provision by agri-cooperatives engaged in high value markets

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    Markets for agricultural products with special quality, environmental, and social attributes can provide a profitable outlet for poor farmers in developing countries. However, participation in high value markets requires that farmers commit to deliver pre-identified volumes on time and in the required form and quality – a tall order in many cases. Agri-cooperatives play an important role in linking farmers to these markets; they forge business relations with distant buyers, realise economies of scale in processing and marketing, and provide advisory and other services to help their members respond to buyer demands. Examples of these services include technical assistance, training, and input and credit provision. This note presents a practical approach by which cooperatives strengthen their ability to deliver impactful and financially sustainable services. In doing so, it recognises the challenges faced by cooperatives to design services that both meet the different needs of members and are financially sustainable. Too often cooperative services are supported by external actors with no clear vision of how to continue once project support terminates, leading to disrupted service offerings for members, and fragmented learning processes for cooperatives and their partners. Innovation is urgently needed in how services are designed, how they are implemented, and cost recovery mechanisms. At the heart of the approach lies a focus on joint learning among stakeholders – cooperatives, their business partners, government agencies, and non-government organisations (NGOs) – to better tackle the complexity inherent in the provision of effective services to poor farmers
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