39,973 research outputs found

    Exploratory electromagnetic thruster research, phase 3, 23 June - 23 December 1969

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    Performance evaluation of MPD arc jets operating in quasi-steady mode

    Investigation of pulsed quasi-steady MPD arc jets

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    Evaluation of magnetohydrodynamic arc thrusters operating in quasi-steady mode with electrode vapor as propellan

    Addressing potential sources of variation in several non-destructive techniques for measuring firmness in apples

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    Measurements of firmness have traditionally been carried out according to the Magness Taylor (MT) procedure; using a texture analyser or penetrometer in reference texture tests. Non-destructive tests like the acoustic impulse response of acoustic firmness sensors (AFSs), a low-mass impact firmness sensor Sinclair International (SIQ-FT) and impact test (Lateral Impact – UPM) have also been used to measure texture and firmness. The objectives of this study were to evaluate the influence of different sources of variation in these three non-destructive tests and to evaluate their respective capabilities of discriminating between fruit maturity at two different harvest dates, turgidity before and after dehydration treatment and ripening after different storage periods. According to our results, fruit studied an unexpected AFS trend with turgidity. Contact measurements (Lateral Impact – UPM and SIQ-FT) appeared highly sensitive to changes in turgidity, but were less able to follow changes in ripening caused by storage period. Contact measurements were suitable for detecting differences between fruits from different harvest dates and showed higher correlation coefficients with reference texture tests than acoustic measurements. The Lateral Impact – UPM test proved better at separating fruits according to turgidity than the SIQ-FT instrumen

    Handbook of recommended practices for the determination of liquid monopropellant rocket engine performance

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    The design, installation, and operation of systems to be used for directly measuring quantities of fundamental importance to the determination of monopropellant thruster performance is described. Areas covered include: (1) force and impulse measurement; (2) propellant mass usage and flow measurement; (3) pressure measurement; (4) temperature measurement; (5) exhaust gas composition measurement; and (6) data reduction and performance determination

    On the resistance of the instrument

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    I examine the role that the musical instrument plays in shaping a performer's expressive activity and emotional state. I argue that the historical development of the musical instrument has fluctuated between two key values: that of sharing with other musicians, and that of creatively exploring new possibilities. I introduce 'the mood organ'- a sensor-based computer instrument that automatically turns signals of the wearer's emotional state into expressive music

    Preliminary Solar Sail Design and Fabrication Assessment: Spinning Sail Blade, Square Sail Sheet

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    Blade design aspects most affecting producibility and means of measurement and control of length, scallop, fullness and straightness requirements and tolerances were extensively considered. Alternate designs of the panel seams and edge reinforcing members are believed to offer advantages of seam integrity, producibility, reliability, cost and weight. Approaches to and requirements for highly specialized metalizing methods, processes and equipment were studied and identified. Alternate methods of sail blade fabrication and related special machinery, tooling, fixtures and trade offs were examined. A preferred and recommended approach is also described. Quality control plans, inspection procedures, flow charts and special test equipment associated with the preferred manufacturing method were analyzed and are discussed

    Performance of a UTC FW-4S solid propellant rocket motor under the command effects of simulated altitude and rotational spin

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    One United Technology Center FW-4S solid-propellant rocket motor was fired at an average simulated altitude of 103,000 ft while spinning about its axial centerline at 180 rpm. The objectives of the test program were to determine motor altitude ballistic performance including the measurement of the nonaxial thrust vector and to demonstrate structural integrity of the motor case and nozzle. These objectives are presented and discussed
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