8,030 research outputs found

    Study of LANDSAT-D thematic mapper performance as applied to hydrocarbon exploration

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    Improved delineation of known oil and gas fields in southern Ontario and a spectacularly high amount of structural information on the Owl Creek, Wyoming scene were obtained from analysis of TM data. The use of hue, saturation, and value image processing techniques on a Death Valley, California scene permitted direct comparison of TM processed imagery with existing 1:250,000 scale geological maps of the area and revealed small outcrops of Tertiary volcanic material overlying Paleozoic sections. Analysis of TM data over Lawton, Oklahoma suggests that the reducing chemical environment associated with hydrocarbon seepage change ferric iron to soluble ferrous iron, allowing it to be leached. Results of the band selection algorithm show a suprising consistency, with the 1,4,5 combination selected as optimal in most cases

    A comparison of fatigue life prediction methodologies for rotorcraft

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    Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra

    Occurrences of \u3ci\u3eEumorpha Fasciata, Hyles Gallii, Sphinx Franckii\u3c/i\u3e and \u3ci\u3eS. Vashti\u3c/i\u3e (Lepidoptera: Sphingidae) in Illinois

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    A recent survey of private and institutional collections in Illinois and surrounding states has provided specific information on the occurrences of four species of sphingids within Illinois: Eumorpha fasciata, Hyles gallii, Sphinx franckii, and S. vashti. Geographical and phenological data for these species are provided

    Evaluation of the suitability of Skylab data for the purpose of petroleum exploration

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    There are no author-identified significant results in this report
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