4,574 research outputs found

    Study of advanced bladder technology, OF2 diborane Final report, 2 Sep. 1969 - 1 Jul. 1970

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    Development and characteristics of elastomeric materials for positive expulsion bladder

    Satellite microwave observations of soil moisture variations

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    The electrically scanning microwave radiometer (ESMR) on the Nimbus 5 satellite was used to observe microwave emissions from vegetated and soil surfaces over an Illinois-Indiana study area, the Mississippi Valley, and the Great Salt Lake Desert in Utah. Analysis of microwave brightness temperatures (T sub B) and antecedent rainfall over these areas provided a way to monitor variations of near-surface soil moisture. Because vegetation absorbs microwave emission from the soil at the 1.55 cm wavelength of ESMR, relative soil moisture measurements can only be obtained over bare or sparsely vegetated soil. In general T sub B increased during rainfree periods as evaporation of water and drying of the surface soil occurs, and drops in T sub B are experienced after significant rainfall events wet the soil. Microwave observations from space are limited to coarse resolutions (10-25 km), but it may be possible in regions with sparse vegetation cover to estimate soil moisture conditions on a watershed or agricultural district basis, particularly since daily observations can be obtained

    Treatment of metal surfaces for use with space storable propellants - A critical survey

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    Treatment of metallic surfaces for use with space storable propellant

    Scientific Objectives for UV/Visible Astrophysics Investigations: A Summary of Responses by the Community (2012)

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    Following several recommendations presented by the Astrophysics Decadal Survey 2010 centered around the need to define "a future ultraviolet-optical space capability," on 2012 May 25, NASA issued a Request for Information (RFI) seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science investigations. The goal was to develop a cohesive and compelling set of science objectives that motivate and support the development of the next generation of ultraviolet/visible space astrophysics missions. Responses were due on 10 August 2012 when 34 submissions were received addressing a number of potential science drivers. A UV/visible Mission RFI Workshop was held on 2012 September 20 where each of these submissions was summarized and discussed in the context of each other. We present a scientific analysis of these submissions and presentations and the pursuant measurement capability needs, which could influence ultraviolet/visible technology development plans for the rest of this decade. We also describe the process and requirements leading to the inception of this community RFI, subsequent workshop and the expected evolution of these ideas and concepts for the remainder of this decade.Comment: 22 pages, 1 figure, 3 table

    Existence theorems in the geometrically non-linear 6-parametric theory of elastic plates

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    In this paper we show the existence of global minimizers for the geometrically exact, non-linear equations of elastic plates, in the framework of the general 6-parametric shell theory. A characteristic feature of this model for shells is the appearance of two independent kinematic fields: the translation vector field and the rotation tensor field (representing in total 6 independent scalar kinematic variables). For isotropic plates, we prove the existence theorem by applying the direct methods of the calculus of variations. Then, we generalize our existence result to the case of anisotropic plates. We also present a detailed comparison with a previously established Cosserat plate model.Comment: 19 pages, 1 figur

    On Chromospheric Variations Modeling for Main-Sequence Stars of G and K Spectral Classes

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    We present a method of chromospheric flux simulation for 13 late-type main-sequence stars. These Sun-like stars have well-determined cyclic flux variations similar to 11 yr solar activity cycle. Our flux prediction is based on chromospheric HK emission time series measurements from Mount Wilson Observatory and comparable solar data. We show that solar three - component modeling explains well the stellar observations. We find that the 10 - 20% of K - stars disc surfaces are occupied by bright active regions.Comment: 8 pages, 2 figure

    Simulation and Analysis Chain for Acoustic Ultra-high Energy Neutrino Detectors in Water

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    Acousticneutrinodetectionisapromisingapproachforlarge-scaleultra-highenergyneutrinodetectorsinwater.In this article, a Monte Carlo simulation chain for acoustic neutrino detection devices in water will be presented. The simulation chain covers the generation of the acoustic pulse produced by a neutrino interaction and its propagation to the sensors within the detector. Currently, ambient and transient noise models for the Mediterranean Sea and simulations of the data acquisition hardware, equivalent to the one used in ANTARES/AMADEUS, are implemented. A pre-selection scheme for neutrino-like signals based on matched filtering is employed, as it is used for on-line filtering. To simulate the whole processing chain for experimental data, signal classification and acoustic source reconstruction algorithms are integrated in an analysis chain. An overview of design and capabilities of the simulation and analysis chain will be presented and preliminary studies will be discussed.Comment: 6 pages, 5 figures, ARENA 2012. arXiv admin note: substantial text overlap with arXiv:1304.057

    GRAND MAL SEIZURE AFTER EXTRADURAL MORPHINE ANALGESIA

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    SUMMARY Following an elective Caesarean section under extradural anaesthesia, a 30-yr-old known epileptic woman (gravida 4, para 3) developed a tonic-clonic seizure, 6 h after the administration of morphine 3 mg into the extradural space. Possible aetiological factors are discusse
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