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The complex interactions between internal motor generated pressure oscillations and motor structural vibration modes associated with the static test configuration of a Reusable Solid Rocket Motor have potential to generate signifi...
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The complex interactions between internal motor generated pressure oscillations and motor structural vibration modes associated with the static test configuration of a Reusable Solid Rocket Motor have potential to generate significant dynamic thrust loads in the 5-segment configuration (Engineering Test Motor 3). Finite element model load predictions for worst-case conditions were generated based on extrapolation of a previously correlated 4-segment motor model. A modal survey was performed on the largest rocket motor to date, Engineering Test Motor no. 3 (ETM-3), to provide data for finite element model correlation and validation of model generated design loads. The modal survey preparation included pretest analyses to determine an efficient analysis set selection using the Effective Independence Method and test simulations to assure critical test stand component loads did not exceed design limits. Historical Reusable Solid Rocket Motor modal testing, ETM-3 test analysis model development and pre-test loads analyses, as well as test execution, and a comparison of results to pre-test predictions are discussed.
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This document reports the results of a study mandated by the United States Congress in December 2003 as part of the Vision 100-Century of Aviation Reauthorization Act (H.R. 2115, Public Law 108-176). Section 321 of the legislation...
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This document reports the results of a study mandated by the United States Congress in December 2003 as part of the Vision 100-Century of Aviation Reauthorization Act (H.R. 2115, Public Law 108-176). Section 321 of the legislation mandates that the Secretary of Transportation, in consultation with the Administrator of the National Aeronautics and Space Administration, shall conduct a study of ways to reduce aircraft noise and emissions and to increase aircraft fuel efficiency. Fifty-nine stakeholders from 38 organizations spanning the aerospace industry, the National Aeronautics and Space Administration (NASA), Federal Aviation Administration (FAA), the Environmental Protection Agency (EPA), the Department of Commerce (DOC), the Department of Defense (DoD), academia, local government and community activists, participated in formulating the recommendations in this study.
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Human event-related potentials (ERPs) were recorded from 10 subjects presented with visual target and nontarget stimuli at five screen locations and responding to targets presented at one of the locations. The late positive respon...
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Human event-related potentials (ERPs) were recorded from 10 subjects presented with visual target and nontarget stimuli at five screen locations and responding to targets presented at one of the locations. The late positive response complexes of 25-75 ERP average waveforms from the two task conditions were simultaneously analyzed with independent Component Analysis, a new computational method for blindly separating linearly mixed signals. Three spatially fixed, temporarily independent, behaviorally relevant, and physiologically plausible components were identified without reference to peeks in single-channel waveforms.
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Probabilistic structural analyses and design methods are steadily gaining acceptance within the aerospace industry. The safety factor approach to design has long been the industry standard, and it is believed by many to be overly ...
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Probabilistic structural analyses and design methods are steadily gaining acceptance within the aerospace industry. The safety factor approach to design has long been the industry standard, and it is believed by many to be overly conservative and thus, costly. A probabilistic approach to design may offer substantial cost savings. This report summarizes several probabilistic approaches: the probabilistic failure analysis (PFA) methodology developed by Jet Propulsion Laboratory, fast probability integration (FPI) methods, the NESSUS finite element code, and response surface methods. Example problems are provided to help identify the advantages and disadvantages of each method.
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摘要 :
Probabilistic structural analyses and design methods are steadily gainingacceptance within the aerospace industry. The safety factor approach to design has long been the industry standard, and it is believed by many to be overly c...
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Probabilistic structural analyses and design methods are steadily gainingacceptance within the aerospace industry. The safety factor approach to design has long been the industry standard, and it is believed by many to be overly conservative and thus, costly. A probabilistic approach to design may offer substantial cost savings. This report summarizes several probabilistic approaches: the probabilistic failure analysis (PFA) methodology developed by Jet Propulsion Laboratory, fast probability integration (FPI) methods, the NESSUS finite element code, and response surface methods. Example problems are provided to help identify the advantages and disadvantages of each method.
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The study addresses a concern, expressed inside and outside the discipline ofobstetrics and gynecology (OB/GYN), that women's health is suffering because of weakness in the research capabilities of academic departments of OB/GYN. ...
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The study addresses a concern, expressed inside and outside the discipline ofobstetrics and gynecology (OB/GYN), that women's health is suffering because of weakness in the research capabilities of academic departments of OB/GYN. The Committee on Research Capabilities of Academic Departments of OB/GYN was charged with studying the perceived weakness in research and the related shortage of investigators who can build on the successes of the past and contribute to the reproductive sciences in the future. It found that it is particularly difficult to generate interest in a career in OB/GYN research and that individuals who desire such a career confront special problems. Few role models are available. The prolonged, clinically focused residency and subspecialty training periods are thought to deter the would-be investigator. Finally, the lack of federal funding for fetal research is thought to both curtail OB/GYN research activities and act as a deterrent to the pursuit of investigative careers in this area. This report will assess the reality of some of these perceptions, which are listed here to indicate the prevailing thoughts and perceptions that lie behind this study.
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This monograph examines the employment of a European based U.S. heavy division ina contingency in the Middle East. Applicable theory is described and developed against the historical lens of armored campaigns in desert regions and...
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This monograph examines the employment of a European based U.S. heavy division ina contingency in the Middle East. Applicable theory is described and developed against the historical lens of armored campaigns in desert regions and then is used to develop the research paper's product: employment considerations. The strategic setting of the Middle East demands sustained attention from the United States. We can expect continued trouble and violence resulting from the diverse religious, cultural, economic, and military pressures within the area. We will most likely see United States interests in protecting sovereign nations and encouraging peace in the region. Since the diminished Soviet threat in Europe no longer fixes divisions in position, a heavy division could be available for employment in the adjacent theater, the Middle East. The criteria introduced to develop the analysis are the dynamics of combat power: maneuver, firepower, protection and leadership. These are examined from theoretical and historical frames of reference that include the German World War II North African campaign, Arab-Israeli wars, and the recent Iran-Iraq War.
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A series of tests were performed by the Federal Aviation Administration (FAA) Technical Center at the Miami/Tamiami, Florida Airport to verify the guidance material contained in the proposed amendments to Attachment G to Part I of...
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A series of tests were performed by the Federal Aviation Administration (FAA) Technical Center at the Miami/Tamiami, Florida Airport to verify the guidance material contained in the proposed amendments to Attachment G to Part I of the International Civil Aviation Organization (ICAO) Annex 10 A mock-up of the category Instrument Landing System (ILS) on runway 9R. Several engineering flight tests were flown with ILS data collected and analyzed. These results were later verified by actually installing the Microwave Landing Systems (MLS) test bed at one of the locations used for the mockup tests. The results indicate that the proposed guidelines are adequate as published, but several items should be considered when implementing these guidelines. These items are presented as recommendations. (kr)
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A series of flight tests were performed by the Federal Aviation Administration (FAA) Technical Center at the Miami/Tamiami, Florida Airport, to compare the course quality of an instrumented landing system (ILS) with a collected Mi...
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A series of flight tests were performed by the Federal Aviation Administration (FAA) Technical Center at the Miami/Tamiami, Florida Airport, to compare the course quality of an instrumented landing system (ILS) with a collected Microwave Landing System (MLS). The Technical Center's test bed MLS was transported to and collected with the commissioned category I ILS on runway 9R at Tamiami. The flight data that was collected indicate that the MLS has less scalloping than the ILS and the MLS azimuth is unaffected by overflight interference. Keywords: Flight control systems; Air navigation; Landing aids; Instrument landing; Instrument flight. (kt)
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