976 research outputs found

    Notes on Neotropical Veliidae (Hemiptera). IX: additional new species of Paravelia from South America

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    Four new species of Paravelia are described: P. dilatata from Surinam and Brazil; P. foveata, P. cupariana and P. juruana from Brazil

    Study made to establish parameters and limitations of explosive welding

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    It is theorized that metal jetting must be present for welding to occur, therefore an explosive weld interface may indicate the relation between the metal jet velocity and shock wave velocity in welding. Parameters for effecting explosive welding in patches of 3 or 4 inches in diameter were established, and found applicable to explosive welding of patches of various sizes

    Prototype microfilm storage and display Final report

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    Prototype microfilm storage and display unit with 6000 frame capacity on 16 mm film, 12 lb weight, and designed for spacecraft us

    Studies on Neotropical Veliidae (Hemiptera). VII. Descriptions of four new species of Paravelia BREDDIN

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    Four new species of Paravelia are described: P. stenoptera and P. spinifera from Surinam; P. manausana from Brazil; P. bullialata from Surinam, Brazil and British Guiana (now Guyana). P. stenoptera n. sp. is the first Paruvelia species known to possess a stridulatory mechanism, consisting of a plectrum on the trochanter and a strigil on the abdomen. Paravelia virtutis DRAKE & HARRIS 1935 is added to the checklist of Paravelia species previously published

    Spin-Spin Interaction In Matrix Theory

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    We calculate the spin dependent static force between two D0-branes in Matrix theory. Supersymmetry relates velocity dependent potentials to spin dependent potentials. The well known v^4/r^7 term is related to a theta^8/r^11 term, where theta is the relative spin of the D0-branes. We calculate this term, confirming that it is the lowest order contribution to the static potential, and find its structure consistent with supergravity.Comment: 15 pages, LaTeX, uses feynmf.sty for diagrams. Reference added and some labels on the diagrams restore

    Pulse transducer with artifact signal attenuator

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    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages

    Results of the Austrian-Ceylonese hydrobiological mission 1970 of the Institute of Zoology of the University of Vienna (Austria) and the Department of Zoology of the University of Sri Lanka, Vidyalankara Campus, Kelaniya. Pt. 19. Aquatic and semiaquatic Hemiptera of Sri Lanka from the Austrian Indo-Pacific expedition, 1970-71

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    This report concerns the aquatic and semiaquatic Hemiptera collected in Sri Lanka by Prof. Starmühlner and Prof. Costa during November and December 1970. A surprising number of new species have been found in the Starmühlner-Costa material, even in groups for which comprehensive revisions exist. Seven new species are described here

    Condition sensor system and method

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    The condition sensor system comprises a condition detector which produces a pulse when a parameter of the monitored condition exceeds a desired threshold. A resettable condition counter counts each pulse. A resettable timer is preset to produce a particular time frame. The counter produces a condition signal when the accumulated number of pulses within the time frame is equal to or greater than a preset count. Control means responsive to the incoming pulses and to the condition signal produce control signals that control utilization devices. After a suitable delay, the last detected pulse simultaneously resets the pulse counter and the timer, and prepares them for sensing another condition occurrence within the time frame. The invention has particular utility in the process of detecting rocking motions of blind people. A controlled, audible, bio-feedback signal is provided which constitutes a warning to the blind person that he is rocking
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