581 research outputs found

    Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

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    A method is described that estimates the error in the static pressure measurement on an aircraft from differential pressure measurements on the hemispherical surface of a Rosemount model 858AJ air velocity probe mounted on a boom ahead of the aircraft. The theoretical predictions for how the pressure should vary over the surface of the hemisphere, involving an unknown sensitivity parameter, leads to a set of equations that can be solved for the unknowns – angle of attack, angle of sideslip, dynamic pressure and the error in static pressure – if the sensitivity factor can be determined. The sensitivity factor was determined on the University of Wyoming King Air research aircraft by comparisons with the error measured with a carefully designed sonde towed on connecting tubing behind the aircraft – a trailing cone – and the result was shown to have a precision of about ±10 Pa over a wide range of conditions, including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system are used to estimate acceleration effects on the error, and the algorithm is shown to predict corrections to a precision of better than ±20 Pa under those conditions. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are discussed

    Analisis Perencanaan Budget Kas Dalam Upaya Menjaga Tingkat Likuiditas USAha (Studi Kasus Pada Koperasi “Sae” Pujon Periode 2013-2017)

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    This research aims to determine application and budget planning of cash in order to maintain the level of liquidity cooperative "SAE" Pujon. The type of research is a case study with descriptive method. The data used in this research is secondary data such as financial data including balance sheet, income statement Koperasi "SAE" Pujon during the period 2013-2015. Based on the research results obtained after performing cash budget projections show that the level of liquidity of cooperatives has increased due to cash and accounts receivable increased. Activity ratio showed a significant increase companies effectively manage assets. The leverage ratio decreased due to the cooperative managed to cut debt. Profitability ratios showed improvement as the percentage increase in net income of cooperatives is relatively smaller than the percentage increase in sales

    Grain‐energy release governs mobility of debris flow due to solid–liquid mass release

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    Debris flows often exhibit high mobility, leading to extensive hazards far from their sources. Although it is known that debris flow mobility increases with initial volume, the underlying mechanism remains uncertain. Here, we reconstruct the mobility–volume relation for debris flows using a recent depth‐averaged two‐phase flow model without evoking a reduced friction coefficient, challenging currently prevailing friction‐reduction hypotheses. Physical experimental debris flows driven by solid–liquid mass release and extended numerical cases at both laboratory and field scales are resolved by the model. For the first time, we probe into the energetics of the debris flows and find that, whilst the energy balance holds and fine and coarse grains play distinct roles in debris flow energetics, the grains as a whole release energy to the liquid due to inter‐phase and inter‐grain size interactions, and this grain‐energy release correlates closely with mobility. Despite uncertainty arising from the model closures, our results provide insight into the fundamental mechanisms operating in debris flows. We propose that debris flow mobility is governed by grain‐energy release, thereby facilitating a bridge between mobility and internal energy transfer. The initial volume of debris flow is inadequate for characterizing debris flow mobility, and a friction‐reduction mechanism is not a prerequisite for the high mobility of debris flows. By contrast, inter‐phase and inter‐grain size interactions play primary roles and should be incorporated explicitly in debris flow models. Our findings are qualitatively encouraging and physically meaningful, providing implications not only for assessing future debris flow hazards and informing mitigation and adaptation strategies, but also for unravelling a spectrum of earth surface processes including heavily sediment‐laden floods, subaqueous debris flows and turbidity currents in rivers, reservoirs, estuaries, and ocean

    Optimal learning paths in information networks

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    Each sphere of knowledge and information could be depicted as a complex mesh of correlated items. By properly exploiting these connections, innovative and more efficient navigation strategies could be defined, possibly leading to a faster learning process and an enduring retention of information. In this work we investigate how the topological structure embedding the items to be learned can affect the efficiency of the learning dynamics. To this end we introduce a general class of algorithms that simulate the exploration of knowledge/information networks standing on well-established findings on educational scheduling, namely the spacing and lag effects. While constructing their learning schedules, individuals move along connections, periodically revisiting some concepts, and sometimes jumping on very distant ones. In order to investigate the effect of networked information structures on the proposed learning dynamics we focused both on synthetic and real-world graphs such as subsections of Wikipedia and word-association graphs. We highlight the existence of optimal topological structures for the simulated learning dynamics whose efficiency is affected by the balance between hubs and the least connected items. Interestingly, the real-world graphs we considered lead naturally to almost optimal learning performances

    Karlstadter Positionspapier zum Schutz der AckerwildkrÀuter. Erarbeitet von den Teilnehmerinnen und Teilnehmern der "Tagung zum Schutz der Ackerwildflora" am 25./26.6.2004 in Karlstadt am Main

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    Der Erhalt von AckerwildkrĂ€utern, die historisch erst mit der Landbewirtschaftung in Mitteleuropa heimisch geworden sind, ist eine Kulturaufgabe, damit auch kĂŒnftige Generationen die Arten- und Farbenvielfalt in der Kulturlandschaft erleben können

    The effectiveness and safety of conservative interventions for positional plagiocephaly and congenital muscular torticollis: A synthesis of systematic reviews and guidance

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    Aim: To investigate for congenital muscular torticollis (CMT) and positional plagiocephaly (PP) the effectiveness and safety of manual therapy, repositioning and helmet therapy (PP only) using a systematic review of systematic reviews and national guidelines. Methods: We searched four major relevant databases: PubMed, Embase, Cochrane and MANTIS for research studies published between the period 1999-2019. Inclusion criteria were systematic reviews that analysed results from multiple studies and guidelines that used evidence and expert opinion to recommend treatment and care approaches. Three reviewers independently selected articles by title, abstract and full paper review, and extracted data. Selected studies were described by two authors and assessed for quality. Where possible meta-analysed data for change in outcomes (range of movement and head shape) were extracted and qualitative conclusions were assessed. Results: We found 10 systematic reviews for PP and 4 for CMT. One national guideline was found for each PP and CMT. For PP, manual therapy was found to be more effective than repositioning including tummy time (moderate to high evidence) but not better than helmet therapy (low evidence). Helmet therapy was better than usual care or repositioning (low evidence); and repositioning better than usual care (moderate to high evidence). The results for CMT showed that manual therapy in the form of practitioner-led stretching had moderate favourable evidence for increased range of movement. Advice, guidance and parental support was recommended in all the guidance to reassure parents of the favourable trajectory and nature of these conditions over time. Conclusions: Distinguishing between superiority of treatments was difficult due to the lack of standardised measurement systems, the variety of outcomes and limited high quality studies. More well powered effectiveness and efficacy studies are needed. However overall, advice and guidance on repositioning (including tummy-time) and practitioner-led stretching were low risk, potentially helpful and inexpensive interventions for parents to consider. Systematic review registration number: PROSPERO 2019 CRD42019139074. © 2020 The Author(s)

    JPL IGS Analysis Center Report, 2001-2003

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    Three GPS orbit and clock products are currently provided by JPL for consideration by the IGS. Each differs in its latency and quality, with later results being more accurate. Results are typically available in both IGS and GIPSY formats via anonymous ftp. Current performance based on comparisons with the IGS final products is summarized. Orbit performance was determined by computing the 3D RMS difference between each JPL product and the IGS final orbits based on 15 minute estimates from the sp3 files. Clock performance was computed as the RMS difference after subtracting a linear trend based on 15 minute estimates from the sp3 files
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