4,640 research outputs found

    A general purpose wideband optical spatial frequency spectrum analyzer

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    The light scattered at various angles by a transparent media is studied. An example of these applications is the optical Fourier spectrum measurement resulting from various spatial frequencies which were recorded on a photographic emulsion. A method for obtaining these measurements consists of illuminating the test object with parallel monochromatic light. A stationary lens, placed in the resulting wavefield at a distance of one focal length from the object, will focus parallel waves emanating from the test object at a point lying in the focal plane of the lens. A light detector with a small filtering aperture is then used to measure the intensity variation of the light in the focal or transform plane of the lens. Such measurements require the use of a lens which is highly corrected for all of the common aberrations except chromatic aberration

    Telecommunications media for the delivery of educational programming

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    The technical characteristics of various telecommunications media are examined for incorporation into educational networks. FM radio, AM radio, and VHF and UHF television are considered along with computer-aided instruction. The application of iteration networks to library systems, and microform technology are discussed. The basic principles of the communications theory are outlined, and the operation of the PLATO 4 random access system is described

    When Hell was in Session

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    Correlation of electrical conductivity and radiation-induced free radical concentration in poly/ethylene terephthalate/ and related compounds

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    Gamma and ultraviolet radiation effects on electronic properties of polyethylene terephthalate and related compound

    Travelling Companions

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    Catalogue to accompany exhibition 'Travelling Companions' at Art at the Alison Richard Building, University of Cambridge. Curator Ro Spankie, Artists Fay Ballard + Judy Goldhil

    Rose of Washington Square

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    https://digitalcommons.library.umaine.edu/mmb-vp/6140/thumbnail.jp

    Dreaming Of Home Sweet Home

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    https://digitalcommons.library.umaine.edu/mmb-vp/3086/thumbnail.jp

    At The End Of The Road

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    Contains advertisements and/or short musical examples of pieces being sold by publisher.https://digitalcommons.library.umaine.edu/mmb-vp/6784/thumbnail.jp

    Analysis of Site Stand Impacts from Thinning with a Harvester-Forwarder System

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    The use of a harvester-forwarder system for commercial thinning operations in a Douglas-fir plantation had little detrimental impact on the residual stand. Less than five percent of the sample trees in the residual stand exhibited damage from the thinning operation. Trails occupied less than 20 percent of the harvested area with significant portions of the developed trail, over 13 percent of the harvested area, in lightly disturbed harvester trails. Trail spacing was consistent and averaged 26 metres between trails for the area studied. Changes in bulk density were greater for harvester trails, increasing an average of 25 percent in the first 10 centimetres of soil depth. Bulk densities on forwarder trails averaged 20 percent greater than measurements on adjacent control sites for the first 10 centimetres of soil depth. These bulk density values, when compared against magnitudes from the literature, suggest that little site damage was caused by thinning operations with this system
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