250 research outputs found

    The NASA Lewis integrated propulsion and flight control simulator

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    A new flight simulation facility was developed at NASA-Lewis. The purpose of this flight simulator is to allow integrated propulsion control and flight control algorithm development and evaluation in real time. As a preliminary check of the simulator facility capabilities and correct integration of its components, the control design and physics models for a short take-off and vertical landing fighter aircraft model were shown, with their associated system integration and architecture, pilot vehicle interfaces, and display symbology. The initial testing and evaluation results show that this fixed based flight simulator can provide real time feedback and display of both airframe and propulsion variables for validation of integrated flight and propulsion control systems. Additionally, through the use of this flight simulator, various control design methodologies and cockpit mechanizations can be tested and evaluated in a real time environment

    Examining the Role of Liaison Librarians as Research Collaboration Partners: A Mixed-Methods Multiple-Case Study

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    This sequential, mixed-methods study explored the professional relationship-building experiences of academic liaison librarians and university professors with a focus on research collaborations. A survey was administered and Chi-square and Spearman\u27s rho analyses conducted on 2,650 responses to identify associations between organizational and individual factors and liaisons\u27 work, perceptions of relationship-building experiences, and confidence in supporting faculty research. Following the survey, seven liaison-faculty pairs were identified and interviewed, and case study analysis utilized to explore specific liaison-faculty research collaboration relationships. The study explored factors associated with liaisons\u27 work, perceptions of faculty relationship-building, and confidence in supporting faculty research. The most salient factors were discipline focus of liaisons\u27 supported areas, percentage of liaisons\u27 position devoted to liaison responsibilities, and holding an additional post-graduate degree. Respondents who supported STEM areas expressed more negative faculty relationship-building experiences and less confidence in their ability to support faculty research. Liaisons with a smaller percentage of their position devoted to liaison work were less likely to provide research support or engage in outreach, were more likely to agree with negative relationship-building statements and more likely to disagree with positive relationship-building statements, and expressed less confidence in their ability to support faculty research activities. Finally, those who held an additional post-graduate degree more often than expected agreed with positive-relationship building statements and expressed more confidence in their ability to support faculty research. While the seven case studies detailed the diverse nature of liaison-faculty research collaboration relationships, within the cases 21 sub-themes were identified and classified into four categories: collaborator traits, collaborator descriptors, feelings/emotions, and potential barriers/facilitators. Common collaborator traits included different areas of expertise and different perspectives. Collaborators were often described as equals, partners, or friends. Emotions/feelings expressed about their relationships included fun, comfort, and trust and respect. Potential barriers to collaborative relationship development included differences in institutional status and liaisons\u27 workload, while institutional support and liaison proactivity were identified as facilitators. This study indicates that liaisons\u27 workload, institutional status, and visibility impact liaisons\u27 ability to develop collaborative research relationships with faculty. To address these areas, it is suggested that liaisons make faculty aware of their availability to collaborate, create faculty advocates to support liaison and library efforts, and be proactive and visible in their efforts to interact with faculty. Based on these findings, suggestions of areas for future research are provided

    Development of Advanced High Lift Leading Edge Technology for Laminar Flow Wings

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    This paper describes the Advanced High Lift Leading Edge (AHLLE) task performed by Northrop Grumman Systems Corporation, Aerospace Systems (NGAS) for the NASA Subsonic Fixed Wing project in an effort to develop enabling high-lift technology for laminar flow wings. Based on a known laminar cruise airfoil that incorporated an NGAS-developed integrated slot design, this effort involved using Computational Fluid Dynamics (CFD) analysis and quality function deployment (QFD) analysis on several leading edge concepts, and subsequently down-selected to two blown leading-edge concepts for testing. A 7-foot-span AHLLE airfoil model was designed and fabricated at NGAS and then tested at the NGAS 7 x 10 Low Speed Wind Tunnel in Hawthorne, CA. The model configurations tested included: baseline, deflected trailing edge, blown deflected trailing edge, blown leading edge, morphed leading edge, and blown/morphed leading edge. A successful demonstration of high lift leading edge technology was achieved, and the target goals for improved lift were exceeded by 30% with a maximum section lift coefficient (Cl) of 5.2. Maximum incremental section lift coefficients ( Cl) of 3.5 and 3.1 were achieved for a blown drooped (morphed) leading edge concept and a non-drooped leading edge blowing concept, respectively. The most effective AHLLE design yielded an estimated 94% lift improvement over the conventional high lift Krueger flap configurations while providing laminar flow capability on the cruise configuration

    Impulsive Injection for Compressor Stator Separation Control

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    Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce separation relative to steady injection for vanes that were induced to separate by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. Variations in injected mass, frequency, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow

    Active Closed-Loop Stator Vane Flow Control Demonstrated in a Low-Speed Multistage Compressor

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    Closed-loop flow control was successfully demonstrated on the surface of stator vanes in NASA Glenn Research Center's Low-Speed Axial Compressor (LSAC) facility. This facility provides a flow field that accurately duplicates the aerodynamics of modern highly loaded compressors. Closed-loop active flow control uses sensors and actuators embedded within engine components to dynamically alter the internal flow path during off-nominal operation in order to optimize engine performance and maintain stable operation

    Closed Loop Active Flow Separation Detection and Control in a Multistage Compressor

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    Active closed loop flow control was successfully demonstrated on a full annulus of stator vanes in a low speed axial compressor. Two independent methods of detecting separated flow conditions on the vane suction surface were developed. The first technique detects changes in static pressure along the vane suction surface, while the second method monitors variation in the potential field of the downstream rotor. Both methods may feasibly be used in future engines employing embedded flow control technology. In response to the detection of separated conditions, injection along the suction surface of each vane was used. Injected mass flow on the suction surface of stator vanes is known to reduce separation and the resulting limitation on static pressure rise due to lowered diffusion in the vane passage. A control algorithm was developed which provided a proportional response of the injected mass flow to the degree of separation, thereby minimizing the performance penalty on the compressor system

    GIS Use in Oral Rabies Vaccine Programs

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    Frequent human and domestic animal exposures to rabid wildlife have raised the public\u27s awareness, leading to an increase in the number of wildlife submissions for rabies testing as well as an increase in the number of people requiring post exposure prophylaxis treatment. During 1998 and 1999, the Health and Human Services Department of a densely populated urban/suburban county in Virginia received a total of 955 animal submissions for rabies testing. Wildlife accounted for 714 of the submissions. Seventy-nine of the submitted wildlife were found dead, 445 were killed or euthanized for testing (190 unknown). Of the wildlife submissions,152 (21%) were positive, including 100 of 178 raccoons submitted. Human exposure, potentially requiring post-exposure prophylaxis, was recorded in 22 positive and 334 negative rabies submissions. Information was not available for 9 positive and 135 negative submissions; human exposure did not occur with the remaining submissions. To reduce the public\u27s risk of exposure to rabid animals, the County is developing a program to distribute oral rabies vaccine to raccoons. To increase the precision of vaccine delivery to raccoons, we propose the use of geographical information systems (GIS) as a method for selecting vaccination sites. Results from trapping and tracking studies, along with hydrographic and vegetation data, were utilized in the development of GIS generated vaccine distribution maps. Also factored in was human activity, commerce, residential housing density, competition by companion animals for vaccine bait, the location of refuse facilities, and property ownership. It is expected that this GIS supported approach will improve the efficiency of the program by lessening the cost while increasing the number of raccoons immunized. The resulting decrease in the incidence of rabies will lead to fewer human exposures to rabid wildlife, a decrease in the number of healthy wildlife euthanized for testing, and a decrease in the number of people requiring post-exposure prophylaxis treatment

    Development and Initial Findings of an Implementation Process Measure for Child Welfare System Change

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    This article describes a new measure designed to examine the process of implementation of child welfare systems change. The measure was developed to document the status of the interventions and strategies that are being implemented and the drivers that are being installed to achieve sustainable changes in systems. The measure was used in a Children’s Bureau-supported national effort to assess the ongoing implementation of 24 systems-change projects in child welfare jurisdictions across the country. The article describes the process for measure development, method of administration and data collection, and quantitative and qualitative findings
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