4,965 research outputs found

    Development of a 60 kW alternator for SNAP-8

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    Design and development testing of 60 kW alternator for SNAP

    Highly loaded multi-stage fan drive turbine: Performance of final three configurations

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    Results for a three-stage highly loaded fan drive turbine follow-on test program are presented. The effects of combinations of tandem and leaned bladerows on three-stage turbine performance were tested. The three-stage turbine with a tandem stator in stage two exhibited a total-to-total efficiency of approximately 0.887 as compared to 0.886 for the plain blade turbine base case

    Lethal Temperatures of Diapausing \u3ci\u3eBathyplectes Curculionis\u3c/i\u3e (Hymenoptera: Ichneumonidae) a Parasite of the Alfalfa Weevil (Coleoptera: Curculionidae)

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    Seasonally acclimatized diapausing larvae of Bathyplectes curculionis (Thomson) were exposed to extreme hxgh and low temperatu~es to determine lethal temperatures for this stage of the parasite. The possible effects of relative humidity on high temperature mortality, mortality induced by repetitive exposures to sublethal temperatures, and differential survival between sexes, were also measured. The upper lethal temperature for summer larvae was 60°C (LDSo from 2 to 4 h), and the lower lethal temperature for winter larvae was -25°C (LDSo from 0 to % h). Summer larvae showed significantly increased mortality with repetitive exposures to sublethal temperatures (55OC) whereas winter larval mortality did not increase significantly with repetitive exposures to sublethal temperatures (-20°C). In winter experiments in which the sex of the emerging adult could be measured, no significant difference in survival was found between the sexes. Our results, in conjunction with published field data, strongly suggest that heat kill in the summer may be a significant mortality factor in warmer areas of the parasite\u27s range

    NASA/GE Energy Efficient Engine low pressure turbine scaled test vehicle performance report

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    The low pressure turbine for the NASA/General Electric Energy Efficient Engine is a highly loaded five-stage design featuring high outer wall slope, controlled vortex aerodynamics, low stage flow coefficient, and reduced clearances. An assessment of the performance of the LPT has been made based on a series of scaled air-turbine tests divided into two phases: Block 1 and Block 2. The transition duct and the first two stages of the turbine were evaluated during the Block 1 phase from March through August 1979. The full five-stage scale model, representing the final integrated core/low spool (ICLS) design and incorporating redesigns of stages 1 and 2 based on Block 1 data analysis, was tested as Block 2 in June through September 1981. Results from the scaled air-turbine tests, reviewed herein, indicate that the five-stage turbine designed for the ICLS application will attain an efficiency level of 91.5 percent at the Mach 0.8/10.67-km (35,000-ft), max-climb design point. This is relative to program goals of 91.1 percent for the ICLS and 91.7 percent for the flight propulsion system (FPS)

    Energy efficient engine. Low pressure turbine test hardware detailed design report

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    The low pressure turbine for the energy efficient engine is a five-stage configuration with moderate aerodynamic loading incorporating advanced features of decambered airfoils and extended blade overlaps at platforms and shrouds. Mechanical integrity of 18,000 hours on flowpath components and 36,000 hours on all other components is achieved along with no aeromechanical instabilities within the steady-state operating range. Selection of a large number (156) of stage 4 blades, together with an increased stage 4 vane-to-blade gap, assists in achieving FAR 36 acoustic goals. Active clearance control (ACC) of gaps at blade tips and interstage seals is achieved by fan air cooling judiciously applied at responsive locations on the casing. This ACC system is a major improvement in preventing deterioration of the 0.0381 cm (0.015 in.) clearances required to meet the integrated-core/low-spool turbine efficiency goal of 91.1% and the light propulsion system efficiency goal of 91.7%

    Comparison of Three Different Image Forces for Active Contours on Abdominal Image Boundary Detection

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    Active contour, or snake, is an energy minimizing spline that is useful in image boundary detection. Active contours are stimulated by internal forces, image forces and external forces which maintain the shape of the contours while attract the contours to some desired features, usually edges. Problems in implementing active contours such as convergence and initialization have motivated researchers to modify image forces of the active contours. This paper presents a comparative study among three different image forces: traditional snakes, balloon and gradient vector flow (GVF). The study is validated by experiments on abdominal image boundaries detection. These lead to the conclusion that GVF gives the most appropriate results among the other approaches

    The female horror film audience : viewing pleasures and fan practices

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    What is at stake for female fans and followers of horror cinema? This study explores the pleasures in horror film viewing for female members of the audience. The findings presented here confirm that female viewers of horror do not refuse to look but actively enjoy horror films and read such films in feminine ways. Part 1 of this thesis suggests that questions about the female viewer and her consumption of the horror film cannot be answered solely by a consideration of the text-reader relationship or by theoretical models of spectatorship and identification. A profile of female horror film fans and followers can therefore be developed only through an audience study. Part 2 presents a profile of female horror fans and followers. The participants in the study were largely drawn from the memberships of horror fan groups and from the readerships of a cross-section of professional and fan horror magazines. Qualitative data were collected through focus groups, interviews, open-ended questions included in the questionnaire and through the communication of opinions and experiences in letters and other written material. Part 3 sheds light on the modes of interpretation and attempts to position the female viewers as active consumers of horror films. This study concludes with a model of the female horror film viewer which points towards areas of female horror film spectatorship which require further analysis. The value of investigating the invisible experiences of women with popular culture is demonstrated by the very large proportion of respondents who expressed their delight and thanks in having an opportunity to speak about their experiences. This study of female horror film viewers allows the voice of an otherwise marginalised and invisible audience to be heard, their experiences recorded, the possibilities for resistance explored, and the potentially feminine pleasures of the horror film identified
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