9,282 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

    Development of a prototype plastic space erectable satellite Quarterly report, Sep. - Nov. 1965

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    Test program for cap section mesh fabrication in prototype space erectable satellite developmen

    Satellite lifetime routine user's manual

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    A FORTRAN coded computer program which determines secular variations in mean orbital elements of earth satellites and the lifetime of the orbit is described. The dynamical model treats a point mass satellite subject to solar and lunar disturbing gravitational fields, second, third and fourth harmonics of the earth's oblate potential, earth's atmospheric drag, and solar radiation pressure. Each of these disturbing functions may be selectively simulated. Data preparation instructions, a sample problem, and definitions of output quantities are included

    Implications of information from LANDSAT-4 for private industry

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    The broader spectral coverage and higher resolution of LANDSAT-4 Thematic Mapper (TM) data open the door for identification from space of spectral phenomena associated with mineralization and microseepage of hydrocarbon. Digitally enhanced image products generated from TM data allow the mapping of many major and minor structural features that mark or influence emplacement of mineralization and accumulation of hydrocarbons. These improvements in capabilities over multispectral scanner data should accelerate the acceptance and integration of satellite data as a routinely used exploration tool that allows rapid examination of large areas in considerable detail. Imagery of Southern Ontario, Canada as well as of Cement, Oklahoma and Death Valley, California is discussed

    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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