1,317 research outputs found

    Marshall system for aerospace system simulation (MARSYAS), user's manual

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    The capabilities of the Marshall system for aerospace system simulation (MARSYAS) and how to use it are described. MARSYAS is a software system that allows easy setup and control of the simulation of the dynamics of large physical systems on a digital computer. The physical systems are modeled in the form of block diagrams or equations. The blocks can have multiple inputs and multiple outputs, and they can be nested to form hierarchies. The block diagrams can contain transfer functions, nonlinear and logical functions, equations, analog computer elements and FORTRAN programs. The input format of the equations can be combinations of nonlinear, time-varying differential equations and algebraic equations in their original format. MARSYAS could also serve as a storage and retrieval system for models as a basis for a model configuration control system on a central time-shared computer. The outputs of the simulation system can be not only time-responses but also other analysis data such as frequency response, power spectrum and stability parameters. The MARSYAS translator is written in FORTRAN running on the Univac 1108 computer under the EXEC 8 operating system

    Marshall system for aerospace simulation (MARSYAS)

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    System is simple flexible language which can be coded by users unfamiliar with computer programming. It is designed for engineers with little experience in simulation, who desire to simulate large physical systems. User has ability to mix differential equations with diagrams in his model. With few exceptions, there is no rigid statement-operator structure within given module

    Leveling coatings for reducing the atomic oxygen defect density in protected graphite fiber epoxy composites

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    Pinholes or other defect sites in a protective oxide coating provide pathways for atomic oxygen in low Earth orbit to reach underlying material. One concept of enhancing the lifetime of materials in low Earth orbit is to apply a leveling coating to the material prior to applying any reflective and protective coatings. Using a surface tension leveling coating concept, a low viscosity epoxy was applied to the surface of several composite coupons. A protective layer of 1000 A of SiO2 was deposited on top of the leveling coating, and the coupons were exposed to an atomic oxygen environment in a plasma asher. Pinhole populations per unit area were estimated by counting the number of undercut sites observed by scanning electron microscopy. Defect density values of 180,000 defects/sq cm were reduced to about 1000 defects/sq cm as a result of the applied leveling coating. These improvements occur at a mass penalty of about 2.5 mg/sq cm

    Nuclear Signaling Pathways for 1,25-Dihydroxyvitamin D 3 Are Controlled by the Vitamin A Metabolite, 9-cis-Retinoic Acid

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75392/1/j.1753-4887.1993.tb03060.x.pd

    Using Photovoice in PETE Programs to Initiate Positive Change

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    The purpose of this presentation will be to provide teacher educators with an overview of the Photovoice methodology and its potential utility in curricular change. The National Association for Sport and Physical Education’s ([NASPE], 2008) PETE standards state educators should allow diversity to drive instructional related decision-making. Photovoice, a participatory action research methodology, is a tool teacher educators can use to be responsive to the continuously changing contexts of public schools

    Implication of the 2014 World Health Organization Integrated Management of Childhood Illness Pneumonia Guidelines with and without pulse oximetry use in Malawi: A retrospective cohort study [version 2; peer review: 2 approved]

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    Background: Under-5 pneumonia mortality remains high in low-income countries. In 2014 the World Health Organization (WHO) advised that children with chest indrawing pneumonia, but without danger signs or peripheral oxygen saturation (SpO 2) < 90% be treated in the community, rather than hospitalized. In Malawi there is limited pulse oximetry availability. Methods: Secondary analysis of 13,413 under-5 pneumonia cases in Malawi. Pneumonia associated case fatality ratios (CFR) were calculated by disease severity under the assumptions of the 2005 and 2014 WHO Integrated Management of Childhood Illness (IMCI) guidelines, with and without pulse oximetry. We investigated if pulse oximetry readings were missing not at random (MNAR). Results: The CFR of patients classified as having non-severe pneumonia per the 2014 IMCI guidelines doubled under the assumption that pulse oximetry was not available (1.5% without pulse oximetry vs 0.7% with pulse oximetry, P<0.001). When 2014 IMCI guidelines were applied with pulse oximetry and a SpO 2 < 90% as the threshold for referral and/or admission, the number of cases meeting hospitalization criteria decreased by 70.3%. Unrecorded pulse oximetry readings were MNAR with an adjusted odds for mortality of 4.9 (3.8, 6.3), similar to that of a SpO 2 < 90%. Although fewer girls were hospitalized, female sex was an independent mortality risk factor. Conclusions: In Malawi, implementation of the 2014 WHO IMCI pneumonia guidelines, without pulse oximetry, will miss high risk cases. Alternatively, implementation of pulse oximetry may result in a large reduction in hospitalization rates without significantly increasing non-severe pneumonia associated CFR if the inability to obtain a pulse oximetry reading is considered a WHO danger sign

    Performance and Carcass Characteristics of Feedlot Steers: Effects of Delayed Implanting and Programmed Feeding During the Growing Period

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    This experiment was conducted to determine the effect of programming the rate of gain and delaying the first implant in feedlot steers on feedlot performance and carcass characteristics. Ninety-six growing steers (269 ± 16.2 kg) were assigned to 12 pens in a completely randomized design. Treatments were implant (Synovex-S®; 20 mg estradiol benzoate and 200 mg progesterone; Fort Dodge Animal Health, Overland Park, KS) on d 1 or no implant and programmed feeding to gain at a slow (0.68 kg/d) or fast (1.14 kg/d) rate during the growing period; these treatments were randomly assigned (n = 8) to pens of steers in a 2 × 2 factorial arrangement. Steers were fed a growing diet and after 88 and 60 d (for steers fed to gain at a slow or fast rate, respectively), steers were transitioned to ad libitum consumption of a high concentrate finishing diet. Growing period implant treatments did not affect ADG but did affect (P\u3c0.01) gain efficiency during the finishing period. Feeding steers for a slow rate of BW gain during the growing period improved (P=0.062) gain efficiency in the finishing period (169 vs 145 g gain/kg feed). Correlation coefficients between fat thickness and marbling score obtained via ultrasound and fat thickness and marbling score measured at harvest were greater the closer the ultrasound measurements were made to the final harvest date. These data indicate that feeding level prior to the start of the finishing period may affect BW gain efficiency during the finishing period

    Process of Producing Equine Viral Arteritis Vaccine and Product Thereof

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    A process is disclosed for producing an avirulent attenuated live virus vaccine for use in immunizing horses against equine viral arteritis and for simultaneously obviating the transmission of the disease from a vaccinated horse to a non-vaccinated horse. The invention also includes the product derived from practice of the process and typical examples of the efficacy of the product are disclosed

    Marshall Space Flight Center Electromagnetic Compatibility Design and Interference Control (MEDIC) handbook

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    The purpose of the MEDIC Handbook is to provide practical and helpful information in the design of electrical equipment for electromagnetic compatibility (EMS). Included is the definition of electromagnetic interference (EMI) terms and units as well as an explanation of the basic EMI interactions. An overview of typical NASA EMI test requirements and associated test setups is given. General design techniques to minimize the risk of EMI and EMI suppression techniques at the board and equipment interface levels are presented. The Handbook contains specific EMI test compliance design techniques and retrofit fixes for noncompliant equipment. Also presented are special tests that are useful in the design process or in instances of specification noncompliance
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