9,760 research outputs found

    Observation of Spin Wave Soliton Fractals in Magnetic Film Active Feedback Rings

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    The manifestation of fractals in soliton dynamics has been observed for the first time. The experiment utilized self-generated spin wave envelope solitons in a magnetic film based active feedback ring. At high ring gain, the soliton that circulates in the ring breathes in a fractal pattern. The corresponding power frequency spectrum shows a comb structure, with each peak in the comb having its own comb, and so on, to finer and finer scales.Comment: 4 pages, 4 figure

    Motion-base simulator study of control of an externally blown flap STOL transport aircraft after failure of an outboard engine during landing approach

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    A moving-base simulator investigation of the problems of recovery and landing of a STOL aircraft after failure of an outboard engine during final approach was made. The approaches were made at 75 knots along a 6 deg glide slope. The engine was failed at low altitude and the option to go around was not allowed. The aircraft was simulated with each of three control systems, and it had four high-bypass-ratio fan-jet engines exhausting against large triple-slotted wing flaps to produce additional lift. A virtual-image out-the-window television display of a simulated STOL airport was operating during part of the investigation. Also, a simple heads-up flight director display superimposed on the airport landing scene was used by the pilots to make some of the recoveries following an engine failure. The results of the study indicated that the variation in visual cues and/or motion cues had little effect on the outcome of a recovery, but they did have some effect on the pilot's response and control patterns

    The other side of the story - maternal perceptions of safety advice and information: a qualitative approach

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    Background: A qualitative study of maternal perceptions of home safety advice. The aim was to gain an understanding of maternal perceptions of and possible barriers to the implementation of home safety advice. Methods: Semi-structured interviews with 37 mothers with a child aged less than 5 years of age; 16 were mothers living in an area of socio-economic disadvantage (with a high rate of childhood unintentional injury), 21 were mothers living in an area of relative affluence (with a low rate of childhood unintentional injury). Thematic analysis was used to analyse the data. Results: Although some mothers living in both areas found talking to a health professional about child home safety was helpful, mothers in both areas tended to find talking to other mothers as being more helpful and they preferred this to talking to a professional. Barriers to obtaining safety advice from professionals exist for mothers living in both areas. Mothers living in the advantaged area describe ‘feeling silly’ and that they should ‘know it already’ when talking to professionals. Mothers living in the disadvantaged area are less likely to access home safety advice due to fear of being perceived as an incompetent mother and the fear of social service involvement. Conclusions: Mothers find home safety advice from other parents more useful and prefer this to advice from professionals. This suggests greater use could be made of appropriately trained parents to deliver safety advice and education. Fear and mistrust can limit access to child safety advice in parents living in disadvantaged areas and this may be a potential explanation for differential unintentional injury rates as those who need the advice and support most may be least likely to access it. Further research should explore how professionals can build trust, gain parents’ confidence and provide child safety advice and education that is targeted appropriately to parents living circumstances and their child safety needs

    Lunar hand tools

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    Tools useful for operations and maintenance tasks on the lunar surface were determined and designed. Primary constraints are the lunar environment, the astronaut's space suit and the strength limits of the astronaut on the moon. A multipurpose rotary motion tool and a collapsible tool carrier were designed. For the rotary tool, a brushless motor and controls were specified, a material for the housing was chosen, bearings and lubrication were recommended and a planetary reduction gear attachment was designed. The tool carrier was designed primarily for ease of access to the tools and fasteners. A material was selected and structural analysis was performed on the carrier. Recommendations were made about the limitations of human performance and about possible attachments to the torque driver

    Flight investigation of stall, spin and recovery characteristics of a low-wing, single-engine, T-tail light airplane

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    Flight tests were performed to investigate the stall, spin, and recovery characteristics of a four-place, low-wing, single-engine, T-tail, general aviation research airplane at an aft center-of-gravity position. Most stalls resulted in roll-offs. Spins were oscillatory in roll and pitch at 43 deg angle of attack; the magnitude of the oscillations was determined by aileron position. Power, flap deflection, and landing gear position did not affect the angle of attack to the spin. Antispin rudder followed by forward wheel with ailerons neutral produced the fastest and most consistent recoveries but the initial application of recovery controls did not always stop a spin

    Exploring a developing tourism industry: A resource-based view approach.

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    This exploratory study examines dimensions related to tourism development in the case of Uruguay. Internal and external analyses were conducted to identify key resources to maximise opportunities and minimise threats to the country’s tourism development. The study, which adopts the resource-based view of the firm, is based on the perspectives of key tourism stakeholders. Unstructured, face-to-face interviews were conducted with eight key informants, three representing government institutions, three private, and two public-private. The interviews revealed opportunities in various fronts, primarily consolidating and expanding international markets, and developing additional offerings, including convention/event and heritage tourism to minimise the effects of seasonality. Strong dependence on neighbouring markets, marginal airline connectivity and knowledge of Uruguay internationally were main perceived barriers to further development. The value of employing the resource-based framework in guiding understanding of the themes under investigation was confirmed. Implications emerging from the findings are discussed, and future research directions suggested
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