29,101 research outputs found

    The Short-period Drag Perturbations of the Orbits of Artificial Satellites

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    Short-period perturbation computation of artificial satellite orbits caused by atmospheric dra

    Analytical development of the planetary disturbing function on a digital computer

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    Fortran II IBM 7094 computer program for analytical development of planetary disturbing functio

    Computer modeling of rocket engine ignition transients Final report

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    Computer modeling of rocket engine ignition transient

    ARE CATTLE ON FEED REPORT REVISIONS RANDOM AND DOES INDUSTRY ANTICIPATE THEM?

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    Cattle on Feed (COF) reports are an important source of beef supply information. This study investigates whether COF report revisions are unbiased, random, and anticipated. Initial COF reports are biased, but the bias is economically small. Revisions to COF estimates are not random. Market analysts do not correctly anticipate revisions.Livestock Production/Industries,

    The impact of college student immersion service learning trips on coping with stress and vocational identity

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    This study examined the impact of service learning immersion trips on vocational identity and coping with stress among college students. Fifty-one students (15 males, 36 females) who participated in immersion trips and 76 students (25 males, 51 females) in a non-immersion control group completed a series of questionnaires directly before and immediately after both fall and spring break immersion trips, and during a four-month follow up. Results suggest that, after returning from an immersion trip, students report a greater ability to cope with stress and a somewhat stronger sense of vocational identity relative to students who do not participate in immersion trips

    Effect of Tidal Cycling Rate on the Distribution and Abundance of Nitrogen-Oxidizing Bacteria in a Bench-Scale Fill-and-Drain Bioreactor

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    Most domestic wastewater can be effectively treated for secondary uses by engineered biological systems. These systems rely on microbial activity to reduce nitrogen (N) content of the reclaimed water. Such systems often employ a tidal-flow process to minimize space requirements for the coupling of aerobic and anaerobic metabolic processes. In this study, laboratory-scale tidal-flow treatment systems were studied to determine how the frequency and duration of tidal cycling may impact reactor performance. Fluorescent in situ hybridization and epifluorescence microscopy were used to enumerate the key functional groups of bacteria responsible for nitrification and anaerobic ammonium oxidation (anammox), and N-removal efficiency was calculated via a mass-balance approach. When water was cycled (i.e., reactors were filled and drained) at high frequencies (16–24 cycles day−1), nitrate accumulated in the columns—presumably due to inadequate periods of anoxia that limited denitrification. At lower frequencies, such as 4 cycles day−1, nearly complete N removal was achieved (80–90%). These fill-and-drain systems enriched heavily for nitrifiers, with relatively few anammox-capable organisms. The microbial community produced was robust, surviving well through short (up to 3 h) anaerobic periods and frequent system-wide perturbation
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