544 research outputs found

    Performance of some miniature pressure transducers subjected to high rotational speeds and centripetal accelerations

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    The performance characteristics of several miniature pressure transducers were determined at centripetal accelerations up to 11,200 g's at a rotational speed of 23,000 rpm. The variation in centripetal acceleration was produced by changing radial position of the transducer relative to the center of rotation. Residual zero outputs and transducer sensitivities were determined at 23,000 rpm and compared with those determined at 0 rpm. The actual pressures at the various transducer locations differ from the center line impressed pressures due to a rotational effect. Corrections for this effect were made. A brief description of the test apparatus is included

    Use of small turbine-type flowmeters to measure flow in large pipes

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    Measurement of mass flow in large pipes using small turbine-type flowmeters is discussed. Experiments for determining accuracy of flowmeter and applicability to various types of flow measurement are reported. Illustration of turbine flowmeter and calibration curve are included

    Liquid flow sight assembly Patent

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    High pressure liquid flow sight assembly for wide temperature range applications including cryogenic fluid

    Small turbing-type flowmeters for liquid hydrogen

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    Characteristics of turbine-type flowmeters in two sizes and with various types of bearings are presented. Calibration procedures of instruments are described. Accuracies obtainable under various conditions are analyzed

    Life tests of small turbine-type flowmeters in liquid hydrogen

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    A total of 14 turbine-type flowmeters of 2.5- and 4-cm nominal size were operated for 100 or more hours at an average fluid speed in the unobstructed, upstream pipe of 20 m/s for the smaller meters and 9 m/s for the larger meters. Calibration shifts over a 6.1 range of calibration flow rates varied from 0.5 percent to 1 percent after 50 hr of operation. It is concluded that use of ball bearings with glass-filled Teflon retainers is most likely to produce minimal calibration shift with protracted use. Bearing replacement after 50 to 100 hr is recommended, depending on accuracy requirements, for meters used at the fluid speeds of the tests

    An optical quality meter suitable for cryogenic liquids

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    Construction of instrument to measure ratio of liquid to gas of flowing transparent cryogenic fluid is described. Instrument consists of collimated light source and photoconductive cell. Operation of instrument is described and illustration of equipment is provided

    High pressure cryogenic liquid flow sight assembly provides streamlined flow for easy observation

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    Window assembly facilitates observation of cryogenic liquids flowing through a smooth pipe at pressures up to several hundred pounds per square inch. This high-pressure cryogenic observation assembly which houses a thin wall glass pipe held within a steel retainer can accommodate fluids under a wide range of pressures and temperatures

    Normal Pressure Hydrocephalus as an Unusual Presentation of Supratentorial Extraventricular Space-Occupying Processes: Report on Two Cases

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    Normal pressure hydrocephalus (NPH) is a clinical and radiographic syndrome characterized by ventriculomegaly, abnormal gait, urinary incontinence, and dementia. The condition may occur due to a variety of secondary causes but may be idiopathic in approximately 50% of patients. Secondary causes may include head injury, subarachnoid hemorrhage, meningitis, and central nervous system tumor. Here, we describe two extremely rare cases of supratentorial extraventricular space-occupying processes: meningioma and glioblastoma multiforme, which initially presented with NPH

    Divided Differences & Restriction Operator on Paley-Wiener Spaces PWtaupPW_{tau}^{p} for N−N-Carleson Sequences

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    For a sequence of complex numbers Λ\Lambda we consider the restriction operator RΛR_{\Lambda} defined on Paley-Wiener spaces PWτpPW_{\tau}^{p} (1<p<∞1<p<\infty). Lyubarskii and Seip gave necessary and sufficient conditions on Λ\Lambda for RΛR_{\Lambda} to be an isomorphism between PWτpPW_{\tau}^{p} and a certain weighted lpl^{p} space. The Carleson condition appears to be necessary. We extend their result to N−N-Carleson sequences (finite unions of NN disjoint Carleson sequences). More precisely, we give necessary and sufficient conditions for RΛR_{\Lambda} to be an isomorphism between PWτpPW_{\tau}^{p} and an appropriate sequence space involving divided differences
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