Full-envelope aerodynamic modeling of the Harrier aircraft

A project to identify a full-envelope model of the YAV-8B Harrier using flight-test and parameter identification techniques is described. As part of the research in advanced control and display concepts for V/STOL aircraft, a full-envelope aerodynamic model of the Harrier is identified, using mathematical model structures and parameter identification methods. A global-polynomial model structure is also used as a basis for the identification of the YAV-8B aerodynamic model. State estimation methods are used to ensure flight data consistency prior to parameter identification.Equation-error methods are used to identify model parameters. A fixed-base simulator is used extensively to develop flight test procedures and to validate parameter identification software. Using simple flight maneuvers, a simulated data set was created covering the YAV-8B flight envelope from about 0.3 to 0.7 Mach and about -5 to 15 deg angle of attack. A singular value decomposition implementation of the equation-error approach produced good parameter estimates based on this simulated data set

Flight testing a V/STOL aircraft to identify a full-envelope aerodynamic model

Flight-test techniques are being used to generate a data base for identification of a full-envelope aerodynamic model of a V/STOL fighter aircraft, the YAV-8B Harrier. The flight envelope to be modeled includes hover, transition to conventional flight and back to hover, STOL operation, and normal cruise. Standard V/STOL procedures such as vertical takeoff and landings, and short takeoff and landings are used to gather data in the powered-lift flight regime. Long (3 to 5 min) maneuvers which include a variety of input types are used to obtain large-amplitude control and response excitations. The aircraft is under continuous radar tracking; a laser tracker is used for V/STOL operations near the ground. Tracking data are used with state-estimation techniques to check data consistency and to derive unmeasured variables, for example, angular accelerations. A propulsion model of the YAV-8B's engine and reaction control system is used to isolate aerodynamic forces and moments for model identification. Representative V/STOL flight data are presented. The processing of a typical short takeoff and slow landing maneuver is illustrated

Method and system for an automated tool for en route traffic controllers

A method and system for a new automation tool for en route air traffic controllers first finds all aircraft flying on inefficient routes, then determines whether it is possible to save time by bypassing some route segments, and finally whether the improved route is free of conflicts with other aircraft. The method displays all direct-to eligible aircraft to an air traffic controller in a list sorted by highest time savings. By allowing the air traffic controller to easily identify and work with the highest pay-off aircraft, the method of the present invention contributes to a significant increase in both air traffic controller and aircraft productivity. A graphical computer interface (GUI) is used to enable the air traffic controller to send the aircraft direct to a waypoint or fix closer to the destination airport by a simple point and click action

In silico identification of functional divergence between the multiple groEL gene paralogs in Chlamydiae

<p>Abstract</p> <p>Background</p> <p>Heat-shock proteins are specialized molecules performing different and essential roles in the cell including protein degradation, folding and trafficking. GroEL is a 60 Kda heat-shock protein ubiquitous in bacteria and has been regarded as an important molecule implicated in chronic inflammatory processes caused by <it>Chlamydiae </it>infections. GroEL in <it>Chlamydiae </it>became duplicated at the origin of the <it>Chlamydiae </it>lineage presenting three distinct molecular chaperones, namely the original protein GroEL1 (Ct110), and its paralogous proteins GroEL2 (Ct604) and GroEL3 (Ct755). These chaperones present differential and independent expressions during the different stages of <it>Chlamydiae </it>infections and have been suggested to present differential physiological and regulatory roles.</p> <p>Results</p> <p>In this comprehensive <it>in silico </it>study we show that GroEL protein paralogs have diverged functionally after the different gene duplication events and that this divergence has occurred mainly between GroEL3 and GroEL1. GroEL2 presents an intermediate functional divergence pattern from GroEL1. Our results point to the different protein-protein interaction patterns between GroEL paralogs and known GroEL protein clients supporting their functional divergence after <it>groEL </it>gene duplication. Analysis of selective constraints identifies periods of adaptive evolution after gene duplication that led to the fixation of amino acid replacements in GroEL protein domains involved in the interaction with GroEL protein clients.</p> <p>Conclusion</p> <p>We demonstrate that GroEL protein copies in <it>Chlamydiae </it>species have diverged functionally after the gene duplication events. We also show that functional divergence has occurred in important functional regions of these GroEL proteins and that very probably have affected the ancestral GroEL regulatory role and protein-protein interaction patterns with GroEL client proteins. Most of the amino acid replacements that have affected interaction with protein clients and that were responsible for the functional divergence between GroEL paralogs were fixed by adaptive evolution after the <it>groEL </it>gene duplication events.</p

Flight test evaluation of the E-systems Differential GPS category 3 automatic landing system

Test flights were conducted to evaluate the capability of Differential Global Positioning System (DGPS) to provide the accuracy and integrity required for International Civil Aviation Organization (ICAO) Category (CAT) III precision approach and landings. These test flights were part of a Federal Aviation Administration (FAA) program to evaluate the technical feasibility of using DGPS based technology for CAT III precision approach and landing applications. An IAI Westwind 1124 aircraft (N24RH) was equipped with DGPS receiving equipment and additional computing capability provided by E-Systems. The test flights were conducted at NASA Ames Research Center's Crows Landing Flight Facility, Crows Landing, California. The flight test evaluation was based on completing 100 approaches and landings. The navigation sensor error accuracy requirements were based on ICAO requirements for the Microwave Landing System (MLS). All of the approaches and landings were evaluated against ground truth reference data provided by a laser tracker. Analysis of these approaches and landings shows that the E-Systems DGPS system met the navigation sensor error requirements for a successful approach and landing 98 out of 100 approaches and landings, based on the requirements specified in the FAA CAT III Level 2 Flight Test Plan. In addition, the E-Systems DGPS system met the integrity requirements for a successful approach and landing or stationary trial for all 100 approaches and landings and all ten stationary trials, based on the requirements specified in the FAA CAT III Level 2 Flight Test Plan

Americas Hidden Common Ground on Renewing Democracy

This Public Agenda/USA TODAY Hidden Common Ground survey, which is also part of Public Agenda's ongoing series of Yankelovich Democracy Monitor surveys, was fielded in May 2021. The research updates and expands on findings from Public Agenda's two previous Yankelovich Democracy Monitor surveys, published in 2019 and 2020. The report concludes with reflections on the findings and implications for moving towards a less divisive, more collaborative, and healthier democracy

Americas Hidden Common Ground: Putting Partisan Animosity in Perspective

This Public Agenda/USA TODAY Hidden Common Ground report focuses on affective polarization, meaning negative feelings towards people whose political views differ from one's own. Findings from this nationally representative survey of American adults, fielded in September 2021, include:Americans are united in thinking that partisan hostility and divisiveness harm the country and want a less contentious nation.Most Americans actually do not have strongly unfavorable feelings towards either Democratic or Republican voters.Most Americans believe in the value of differences of opinion and dialogue, and many are trying to connect across partisan lines.A strong cross-partisan majority of Americans believe that the federal government should ensure voting rights for all, and a more modest majority believe that doing so would actually bring the country together. By contrast, partisan differences of opinion emerge starkly when people are asked about federal policies directly aimed at combating racism.To bring the country together, Americans agree on the need for better news and information; and, most want social media to stop amplifying divisiveness.Across partisan lines, most Americans agree that reducing the influence of money in politics would help bring the country together. Many people also believe that educational approaches would help unify the country.The report concludes with reflections on the findings and implications for addressing affective polarization