117 research outputs found

    Characteristics of hingeless rotors with hub moment feedback controls including experimental rotor frequency response, Volume 1

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    Wind tunnel tests to determine the dynamic characteristics of hingeless rotors with hub moment feedback controls and to acquire experimental hingeless rotor transfer functions are discussed. Rotor transfer functions were calculated from data acquired during open loop frequency response tests. The transfer functions are linear and present the rotor longitudinal and lateral frequency responses to collective pitch, longitudinal cyclic pitch, and lateral cyclic pitch. The theoretical analysis was based on the rigid blade flapping model coupled with appropriate control system and cyclic pitch actuator equations of motion

    Research program to determine rotor response characteristics at high advance ratios Final report

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    Stability and response characteristics of directly controlled rigid rotors at high advance ratios and correlation of mathematical model with wind tunnel test dat

    Development of pancreatic diseases during long-term follow-up after acute pancreatitis:a post-hoc analysis of a prospective multicenter cohort

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    Background and Aim: More insight into the incidence of and factors associated with progression following a first episode of acute pancreatitis (AP) would offer opportunities for improvements in disease management and patient counseling. Methods: A long-term post hoc analysis of a prospective cohort of patients with AP (2008–2015) was performed. Primary endpoints were recurrent acute pancreatitis (RAP), chronic pancreatitis (CP), and pancreatic cancer. Cumulative incidence calculations and risk analyses were performed. Results: Overall, 1184 patients with a median follow-up of 9 years (IQR: 7–11) were included. RAP and CP occurred in 301 patients (25%) and 72 patients (6%), with the highest incidences observed for alcoholic pancreatitis (40% and 22%). Pancreatic cancer was diagnosed in 14 patients (1%). Predictive factors for RAP were alcoholic and idiopathic pancreatitis (OR 2.70, 95% CI 1.51–4.82 and OR 2.06, 95% CI 1.40–3.02), and no pancreatic interventions (OR 1.82, 95% CI 1.10–3.01). Non-biliary etiology (alcohol: OR 5.24, 95% CI 1.94–14.16, idiopathic: OR 4.57, 95% CI 2.05–10.16, and other: OR 2.97, 95% CI 1.11–7.94), RAP (OR 4.93, 95% CI 2.84–8.58), prior pancreatic interventions (OR 3.10, 95% CI 1.20–8.02), smoking (OR 2.33, 95% CI 1.14–4.78), and male sex (OR 2.06, 95% CI 1.05–4.05) were independently associated with CP. Conclusion: Disease progression was observed in a quarter of pancreatitis patients. We identified several risk factors that may be helpful to devise personalized strategies with the intention to reduce the impact of disease progression in patients with AP.</p

    Development of pancreatic diseases during long-term follow-up after acute pancreatitis:a post-hoc analysis of a prospective multicenter cohort

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    Background and Aim: More insight into the incidence of and factors associated with progression following a first episode of acute pancreatitis (AP) would offer opportunities for improvements in disease management and patient counseling. Methods: A long-term post hoc analysis of a prospective cohort of patients with AP (2008–2015) was performed. Primary endpoints were recurrent acute pancreatitis (RAP), chronic pancreatitis (CP), and pancreatic cancer. Cumulative incidence calculations and risk analyses were performed. Results: Overall, 1184 patients with a median follow-up of 9 years (IQR: 7–11) were included. RAP and CP occurred in 301 patients (25%) and 72 patients (6%), with the highest incidences observed for alcoholic pancreatitis (40% and 22%). Pancreatic cancer was diagnosed in 14 patients (1%). Predictive factors for RAP were alcoholic and idiopathic pancreatitis (OR 2.70, 95% CI 1.51–4.82 and OR 2.06, 95% CI 1.40–3.02), and no pancreatic interventions (OR 1.82, 95% CI 1.10–3.01). Non-biliary etiology (alcohol: OR 5.24, 95% CI 1.94–14.16, idiopathic: OR 4.57, 95% CI 2.05–10.16, and other: OR 2.97, 95% CI 1.11–7.94), RAP (OR 4.93, 95% CI 2.84–8.58), prior pancreatic interventions (OR 3.10, 95% CI 1.20–8.02), smoking (OR 2.33, 95% CI 1.14–4.78), and male sex (OR 2.06, 95% CI 1.05–4.05) were independently associated with CP. Conclusion: Disease progression was observed in a quarter of pancreatitis patients. We identified several risk factors that may be helpful to devise personalized strategies with the intention to reduce the impact of disease progression in patients with AP.</p

    Review of deuterium–tritium results from the Tokamak Fusion Test Reactor

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    Biostratigraphy of Cretaceous calcareous nannoplankton

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    The stratigraphical distribution of selected species of calcareous nannoplankton from sections of Cretaceous deposits in Tunisia, France, The Netherlands, West Germany, Great Britain, Denmark, Turkey, Oman and New Jersey was studied. A number of Late Cretaceous lineages was recognised, on which a proposal for a revised zonation is based. Twenty-six zones are distinguished for the Cretaceous interval. First-order correlations between zones and Cretaceous stage-s(ratotypes are discussed, briefly. The Upper Cretaceous part of the proposed zonation has also been correlated with planktonic foraminiferal zones. One new genus and two new species' are described

    Fossil Questions : Early History of Palaentology 600 BC - 1800 AD

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    Print on Demand version available via http://www.linguaterraebooks.nl - Modern palaeontology is the earth-scientific specialism that investigates the nature and significance of fossils, that is, the study of the remains of once living organisms which have been preserved in earth’s crust. Palaeontology thus investigates the history of life on earth. It does so by applying biological and geological scientific concepts and knowledge. Before its establishment and rise to a fully-fledged scientific state, this special branch of geology passed through a long period of pre-modern development. This book deals with those generally slow and intermittently stagnant developments in the study of those strange ‘medals of Creation’, that is, the period of gestation of palaeontology as the prime study of ancient life

    Stepping Stones towards Firenze : Geological Thought between Belief and Science 1475-1665

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    Deposits of Earth Science : Printing History of Early Modern Geology 1455-1800

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    Deposits of Earth Science: Printing History of Early Modern Geology 1455-1800

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