4,552 research outputs found

    CF6-6D engine short-term performance deterioration

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    Studies conducted as part of the NASA-Lewis CF6 jet engine diagnostics program are summarized. An 82-engine sample of DC-10-10 aircraft engine checkout data that were gathered to define the extent and magnitude of CF6-6D short term performance deterioration were analyzed. These data are substantiated by the performance testing and analytical teardown of CF6-6D short term deterioration engine serial number (ESN) 451507

    Same Old Song: An Analysis of Adaptation and the Orpheus Myth in Musical Theatre

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    This bibliography is a brief examination of various adaptations of the myth of Orpheus and Euridice throughout the history of musical theatre and opera, specifically through comparative textual analysis of the scripts and libretti. In this examination, additions to or retractions from the original story, whether common to several adaptations or unique to a single source, will be analyzed. From these findings it will be possible to speculate on historical and contextual reasons for the unique shape taken by each adaptation, and to add to the conversation about the nature and purpose of adaptation in general as well as the general cultural prevalence of the Orpheus myth itself

    CF6-6D engine performance deterioration

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    Cruise cockpit recordings and test cell performance data in conjunction with hardware inspection data from airline overhaul shops were analyzed to define the extent and magnitude of performance deterioration of the General Electric CF6-6D model engine. These studies successfully isolated short-term deterioration from the longer term, and defined areas where a significant reduction in aircraft energy requirements for the 1980's can be realized. Unrestored losses which remain after engine refurbishment represent over 70% of the loss at engine shop visit. Sixty-three percent of the unrestored losses are cost-effective to restore which could reduce fuel consumed by CF6-6D engines in 1980 by 10.9 million gallons

    Analysis of interface conversion processes of ballistic and diffusive motion in driven superlattices

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    We explore the non-equilibrium dynamics of non-interacting classical particles in a one-dimensional driven superlattice which is composed of domains exposed to different time-dependent forces. It is shown how the combination of directed transport and conversion processes from diffusive to ballistic motion causes strong correlations between velocity and phase for particles passing through a superlattice. A detailed understanding of the underlying mechanism allows us to tune the resulting velocity distributions at distinguished points in the superlattice by means of local variations of the applied driving force. As an intriguing application we present a scheme how initially diffusive particles can be transformed into a monoenergetic pulsed particle beam whose parameters such as its energy can be varied

    How do numerical methods perform for delay differential equations undergoing a Hopf bifurcation?

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    This paper discusses the numerical solution of delay differential equations undergoing a Hopf birufication. Three distinct and complementary approaches to the analysis are presented.Manchester Centre for Computational Mathematic

    Taxonomic status of the Liberian Greenbul Phyllastrephus leucolepis and the conservation importance of the Cavalla Forest, Liberia

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    We thank Jochen Martens for his long-lasting patience in dealing with the specimen of leucolepis, and Brian Hillcoat for comments and advice. It is hardly possible to thank by name all those who have supported WG over the past 30 years and more since 1981 in the fields of forest ecology and ornithology in eastern Liberia. In particular, we express gratitude to Alex Peal and Theo Freeman, both Heads of Wildlife and National Parks, for their many years of cooperation, and the Silviculture Officers Wynn Bryant, Momo Kromah and Steve Miapeh. The knowledge of the tree experts Joe Keper and Daniel Dorbor helped us to gain insights into the ecological complexities of the relationship between man, birds and trees. William Toe worked for three years as bird trapper and assistant in bird banding. WG’s attachment to the University of Liberia and to the students who so often accompanied him was made possible by Ben Karmorh from the Environmental Protection Agency (EPA) and University of Liberia. NABU, the German Conservation Society, has supported the Liberian projects for almost 30 years now. We also thank Nigel Collar, Françoise Dowsett-Lemaire and Hannah Rowland for comments and advice. We thank the African Bird Club and the Royal Society for the Protection of Birds for helping to fund the 2013 expedition to the Cavalla Forest, in particular Alice Ward-Francis, Robert Sheldon, Alan Williams and Keith Betton. We also are extremely grateful to Michael Garbo and staff of the Society for the Conservation of Nature in Liberia for all manner of help with the expedition, to Harrison Karnwea and colleagues at the Forest Development Authority of Liberia for permissions and other support, as well as to Emmanuel Loqueh, Trokon Grimes, Flomo Molubah and Amos ‘Dweh’ Dorbor for being such excellent companions in the field. YL performed the genetic work as part of her M.Sc. (Genetics) at the University of Aberdeen, whose support is acknowledged.Peer reviewedPublisher PD

    Mechanical On-Chip Microwave Circulator

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    Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. Here, we demonstrate an on-chip magnetic-free circulator based on reservoir engineered optomechanical interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electro-mechanical signal conversion paths. The presented circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. With a high dynamic range, a tunable bandwidth of up to 30 MHz and an in-situ reconfigurability as beam splitter or wavelength converter, it could pave the way for superconducting qubit processors with integrated and multiplexed on-chip signal processing and readout.Comment: References have been update
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