1,514 research outputs found

    Computer program performs aerothermodynamic flight test data correlation

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    Computer program plots flight test data /stored on magnetic tape during the flight/ with comparative data from other tapes /design and post-flight predictions/. Information as to which measurements are on each tape, the order in which they appear, and the exact time span is supplied by the source of the data

    Quiet Clean Short-haul Experimental Engine (QCSEE). Core engine noise measurements

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    Noise measurements were taken on a turbofan engine which uses the same core, with minor modifications, employed on the quiet clean short-haul experimental engine (QCSEE) propulsion systems. Both nearfield and farfield noise measurements were taken in order to determine the core internally generated noise levels. The resulting noise measurements were compared to predicted combustor and turbine noise levels, to verify or improve the predicted QCSEE combustor and turbine noise levels

    Quiet, Clean, Short-Haul Experimental Engine (QCSEE) Over-The-Wing (OTW) engine acoustic design

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    The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the over-the-wing (OTW) nacelle acoustic treatment design are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the OTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment

    Thrust reverser design studies for an over-the-wing STOL transport

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    Aerodynamic and acoustics analytical studies were conducted to evaluate three thrust reverser designs for potential use on commercial over-the-wing STOL transports. The concepts were: (1) integral D nozzle/target reverser, (2) integral D nozzle/top arc cascade reverser, and (3) post exit target reverser integral with wing. Aerodynamic flowpaths and kinematic arrangements for each concept were established to provide a 50% thrust reversal capability. Analytical aircraft stopping distance/noise trade studies conducted concurrently with flow path design showed that these high efficiency reverser concepts are employed at substantially reduced power settings to meet noise goals of 100 PNdB on a 152.4 m sideline and still meet 609.6 m landing runway length requirements. From an overall installation standpoint, only the integral D nozzle/target reverser concept was found to penalize nacelle cruise performance; for this concept a larger nacelle diameter was required to match engine cycle effective area demand in reverse thrust

    TF34 Quiet Nacelle nearfield acoustic test results

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    The results of the nearfield acoustic tests conducted on the TF34 Quiet Nacelle are presented. The high fan noise suppression levels being sought (26 PNdB reduction in aft noise) necessitated the use of an extensive system of special nearfield acoustic instrumentation to properly evaluate the suppression achieved. The design, operation, and test results from each of these nearfield acoustic instrumentation systems are presented

    Acoustic design of the QCSEE propulsion systems

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    Acoustic design features and techniques employed in the Quiet Clean Short-Haul Experimental Engine (QCSEE) Program are described. The role of jet/flap noise in selecting the engine fan pressure ratio for powered lift propulsion systems is discussed. The QCSEE acoustic design features include a hybrid inlet (near-sonic throat velocity with acoustic treatment); low fan and core pressure ratios; low fan tip speeds; gear-driven fans; high and low frequency stacked core noise treatment; multiple-thickness treatment; bulk absorber treatment; and treatment on the stator vanes. The QCSEE designs represent and anticipated acoustic technology improvement of 12 to 16 PNdb relative to the noise levels of the low-noise engines used on current wide-body commercial jet transport aircraft

    The Oyster River Culvert Analysis Project

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    Studies have already detected intensification of precipitation events consistent with climate change projections. Communities may have a window of opportunity to prepare, but information sufficiently quantified and localized to support adaptation programs is sparse: published literature is typically characterized by general resilience building or regional vulnerability studies. The Fourth Assessment Report of the IPCC observed that adaptation can no longer be postponed pending the effective elimination of uncertainty. Methods must be developed that manage residual uncertainty, providing community leaders with decision-support information sufficient for implementing infrastructure adaptation programs. This study developed a local-scale and actionable protocol for maintaining historical risk levels for communities facing significant impacts from climate change and population growth. For a coastal watershed, the study assessed the capacity of the present stormwater infrastructure capacity for conveying expected peak flow resulting from climate change and population growth. The project transferred coupled-climate model projections to the culvert system, in a form understandable to planners, resource managers and decision-makers; applied standard civil engineering methods to reverse-engineer culverts to determine existing and required capacities; modeled the potential for LID methods to manage peak flow in lieu of, or combination with, drainage system upsizing; and estimated replacement costs using local and national construction cost data. The mid-21st century, most likely 25-year, 24-hour precipitation is estimated to be 35% greater than the TP-40 precipitation for the SRES A1b trajectory, and 64% greater than the TP-40 value for the SRES A1fi trajectory. 5% of culverts are already undersized for the TP-40 event to which they should have been designed. Under the most likely A1b trajectory, an additional 12% of culverts likely will be undersized, while under the most likely A1fi scenario, an additional 19% likely will be undersized. These conditions place people and property at greater risk than that historically acceptable from the TP-4025-year design storm. This risk level may be maintained by a long-term upgrade program, utilizing existing strategies to manage uncertainty and costs. At the upper-95% confidence limit for the A1fi 25-year event, 65% of culverts are adequately sized, and building the remaining 35%, and planned, culverts to thrice the cross-sectional area specified from TP-40 should provide adequate capacity through this event. Realizable LID methods can mitigate significant impacts from climate change and population growth, however effectiveness is limited for the more pessimistic climate change projections. Results indicate that uncertainty in coupled-climate model projections is not an impediment to adaptation. This study makes a significant contribution toward the generation of reliable and specific estimates of impacts from climate change, in support of programs to adapt civil infrastructures. This study promotes a solution to today\u27s arguably most significant challenge in civil infrastructure adaptation: translating the extensive corpus of adaptation theory and regional-scale impacts analyses into localscale action

    The Effects of Triclosan on the Dvelopment of Rana Palustris

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    2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

    Retinal redox stress and ultrastructural remodeling in metabolic syndrome and diabetic retinopathy [abstract]

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    Diabetic retinopathy is the major cause of blindness in the United States in the age group from 20-74. There are four traditional metabolic pathways involved in the development of diabetic retinopathy: increased polyol pathway flux, increased advanced glycation end-product formation, activation of protein kinase C (PKC) isoforms, and increased hexosamine pathway flux. These pathways individually and synergistically contribute to redox stress resulting in retinal tissue injury culminating in microvascular retinal remodeling and diabetic retinopathy. We investigated the ultrastructural remodeling of the blood retinal barrier (BRB) in the choroid coat layer and plexiform layers in retinas of the young 9 week old Zucker rat model of obesity and insulin resistance and the 20 week old alloxan diabetic porcine model with JEM -1400 transmission electron microscopy. Previous studies indicated that pericyte loss and dysfunction are the earliest hallmarks of diabetic retinopathy

    Quiet, Clean, Short-Haul, Experimental Engine (QCSEE) Under-The-Wing (UTW) engine acoustic design

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    The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the under-the-wing (UTW) engine boilerplate and composite nacelle acoustic treatment designs are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the UTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment
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