5,591 research outputs found

    The development of selected data base applications for the crustal dynamics data information system

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    The development of a data base and its accompanying software for the data information system of crustal dynamics project is described. Background information concerning this project, and a definition of the techniques used in the implementation of an operational data base, are presented. Examples of key applications are included and interpreted

    Aeroservoelasticity

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    Accomplishments and current research projects along four main thrusts in aeroservoelasticity at the NASA Langley Research Center are described. One activity focuses on enhancing the modelling and the analysis procedures to accurately predict aeroservoelastic interactions. In the area of modelling, improvements to the minimum-state method of approximating unsteady aerodynamics are shown to provide precise, low-order models for design and simulation tasks. Recent extensions in aerodynamic correction factor methodology are also described. With respect to analysis procedures, the paper reviews novel enhancements to Matched Filter Theory and Random Process Theory for predicting the critical gust profile and the associated time-correlated gust loads for structural design considerations. In another activity, two research projects leading towards improved design capability are summarized. The first program involves the development of an integrated structure/control design capability; the second provides procedures for obtaining low-order, robust digital control laws for aeroelastic applications. Experimental validation of new theoretical developments is the third activity. As such, a short description of the Active Flexible Wing Project is presented, and recent wind-tunnel test accomplishments are summarized. Finally within the area of application, a study performed to assess the state-of-the-art of aeroelastic and aeroservoelastic analysis and design technology with respect to hot, hypersonic flight vehicles is reviewed

    Candidate Members and Age Estimate of the Family of Kuiper Belt Object 2003 EL61

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    The collisional family of Kuiper belt object (KBO) 2003 EL61 opens the possibility for many interesting new studies of processes important in the formation and evolution of the outer solar system. As the first family in the Kuiper belt, it can be studied using techniques developed for studying asteroid families, although some modifications are necessary. Applying these modified techniques allows for a dynamical study of the 2003 EL61 family. The velocity required to change orbits is used to quantitatively identify objects near the collision. A method for identifying family members that have potentially diffused in resonances (like 2003 EL61) is also developed. Known family members are among the very closest KBOs to the collision and two new likely family members are identified: 2003 UZ117 and 1999 OY3. We also give tables of candidate family members which require future observations to confirm membership. We estimate that a minimum of ~1 GYr is needed for resonance diffusion to produce the current position of 2003 EL61, implying that the family is likely primordial. Future refinement of the age estimate is possible once (many) more resonant objects are identified. The ancient nature of the collision contrasts with the seemingly fresh surfaces of known family members, suggesting that our understanding of outer solar system surfaces is incomplete.Comment: 22 pages, 5 figures, accepted to AJ, author's cv available at http://www.gps.caltech.edu/~dari

    Wind tunnel investigation of supersonic wing-tail flutter

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    A flutter model, consisting of a wing, horizontal tail, and splitter plate/fuselage mechanism, was tested in a 4-foot transonic tunnel in the Mach number range 1.1 to 1.3. Two types of flutter were encountered during the testing: a wing-tail flutter bending-torsion flutter mode. The wing-tail flutter speed was found to be a minimum at M = 1.2 for the configuration tested. Recorded model test data were digitized for a power spectral density (PSD) analysis and Random Decrement (Randomdec) analysis. Comparisons between the frequency and damping obtained from the PSD plots and the Randomdec signatures agreed very well. A limited flutter analysis was conducted using a Mach box unsteady aerodynamics method which accounted for interference and airfoil thickness. Analytical comparisons with experimental flutter speeds agreed well. The analyses assuming zero thickness predicted flutter speeds higher than those measured, ranging from 1 percent at M = 1.12 to 8 percent at M = 1.28. With the airfoil thickness included, the correlation was improved such that predicted flutter speeds for all cases investigated were within 2 percent of experimental speeds

    Flutter suppression control law synthesis for the Active Flexible Wing model

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    The Active Flexible Wing Project is a collaborative effort between the NASA Langley Research Center and Rockwell International. The objectives are the validation of methodologies associated with mathematical modeling, flutter suppression control law development and digital implementation of the control system for application to flexible aircraft. A flutter suppression control law synthesis for this project is described. The state-space mathematical model used for the synthesis included ten flexible modes, four control surface modes and rational function approximation of the doublet-lattice unsteady aerodynamics. The design steps involved developing the full-order optimal control laws, reducing the order of the control law, and optimizing the reduced-order control law in both the continuous and the discrete domains to minimize stochastic response. System robustness was improved using singular value constraints. An 8th order robust control law was designed to increase the symmetric flutter dynamic pressure by 100 percent. Preliminary results are provided and experiences gained are discussed

    California\u27s New General Corporation Law: Quasi-Foreign Corporations

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    Cultural Diabetes

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    Diabetes has become a cultural problem across America, but particularly in the Midwest and Southern regions. For my film, I explored these two areas and compared the food and exercise culture to one of the healthier regions, the West. Having moved from Indiana to Colorado, I used my own personal experiences to analyze why people in the Midwest struggle with diabetes and obesity at such a higher rate than those nearer to the Pacific Ocean. Through a series of interviews with close friends and observational analysis of each state, I came to learn something very important about health: our food culture is embedded and encouraged by the people that surround us, and changing the way we behave is more than just being taught healthy activities. People can change, but unfortunately I believe the problem is going to have to get worse before America takes it seriously enough to fix it

    Comment on the Revised Proposed Final Judgement

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    In these comments, we argue that the Revised Proposed Final Judgement (RPFJ) is not in the "public interest," as that test is applied under the Tunney Act. Accordingly, the RPFJ should either be rejected outright now, or the court should refrain from ruling on the RPFJ until it has completed its further factual inquiry regarding the remedy proposed by the nine states not party to the RPFJ. If, however, the court accepts the RPFJ in the meantime, we strongly urge it to treat the RPFJ as an interim remedy and expressly leave open the possibility of supplementing the RPFJ with the additional remedies discussed in detail in this comment. We also recommend that in conducting its further factual inquiry in the remedy phase of this litigation that the court actively consider a structural remedy that would create some competition in the PC operating system market that, but for Microsoft's unlawful acts, reasonably could have been expected to have emerged by this time.

    Recent activities within the Aeroservoelasticity Branch at the NASA Langley Research Center

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    The objective of research in aeroservoelasticity at the NASA Langley Research Center is to enhance the modeling, analysis, and multidisciplinary design methodologies for obtaining multifunction digital control systems for application to flexible flight vehicles. Recent accomplishments are discussed, and a status report on current activities within the Aeroservoelasticity Branch is presented. In the area of modeling, improvements to the Minimum-State Method of approximating unsteady aerodynamics are shown to provide precise, low-order aeroservoelastic models for design and simulation activities. Analytical methods based on Matched Filter Theory and Random Process Theory to provide efficient and direct predictions of the critical gust profile and the time-correlated gust loads for linear structural design considerations are also discussed. Two research projects leading towards improved design methodology are summarized. The first program is developing an integrated structure/control design capability based on hierarchical problem decomposition, multilevel optimization and analytical sensitivities. The second program provides procedures for obtaining low-order, robust digital control laws for aeroelastic applications. In terms of methodology validation and application the current activities associated with the Active Flexible Wing project are reviewed
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