Science.gov

Sample records for aerodynamic objective function

  1. Derivation of aerodynamic kernel functions

    NASA Technical Reports Server (NTRS)

    Dowell, E. H.; Ventres, C. S.

    1973-01-01

    The method of Fourier transforms is used to determine the kernel function which relates the pressure on a lifting surface to the prescribed downwash within the framework of Dowell's (1971) shear flow model. This model is intended to improve upon the potential flow aerodynamic model by allowing for the aerodynamic boundary layer effects neglected in the potential flow model. For simplicity, incompressible, steady flow is considered. The proposed method is illustrated by deriving known results from potential flow theory.

  2. Multi-objective aerodynamic shape optimization of small livestock trailers

    NASA Astrophysics Data System (ADS)

    Gilkeson, C. A.; Toropov, V. V.; Thompson, H. M.; Wilson, M. C. T.; Foxley, N. A.; Gaskell, P. H.

    2013-11-01

    This article presents a formal optimization study of the design of small livestock trailers, within which the majority of animals are transported to market in the UK. The benefits of employing a headboard fairing to reduce aerodynamic drag without compromising the ventilation of the animals' microclimate are investigated using a multi-stage process involving computational fluid dynamics (CFD), optimal Latin hypercube (OLH) design of experiments (DoE) and moving least squares (MLS) metamodels. Fairings are parameterized in terms of three design variables and CFD solutions are obtained at 50 permutations of design variables. Both global and local search methods are employed to locate the global minimum from metamodels of the objective functions and a Pareto front is generated. The importance of carefully selecting an objective function is demonstrated and optimal fairing designs, offering drag reductions in excess of 5% without compromising animal ventilation, are presented.

  3. Genetic Algorithms Applied to Multi-Objective Aerodynamic Shape Optimization

    NASA Technical Reports Server (NTRS)

    Holst, Terry L.

    2005-01-01

    A genetic algorithm approach suitable for solving multi-objective problems is described and evaluated using a series of aerodynamic shape optimization problems. Several new features including two variations of a binning selection algorithm and a gene-space transformation procedure are included. The genetic algorithm is suitable for finding Pareto optimal solutions in search spaces that are defined by any number of genes and that contain any number of local extrema. A new masking array capability is included allowing any gene or gene subset to be eliminated as decision variables from the design space. This allows determination of the effect of a single gene or gene subset on the Pareto optimal solution. Results indicate that the genetic algorithm optimization approach is flexible in application and reliable. The binning selection algorithms generally provide Pareto front quality enhancements and moderate convergence efficiency improvements for most of the problems solved.

  4. Genetic Algorithms Applied to Multi-Objective Aerodynamic Shape Optimization

    NASA Technical Reports Server (NTRS)

    Holst, Terry L.

    2004-01-01

    A genetic algorithm approach suitable for solving multi-objective optimization problems is described and evaluated using a series of aerodynamic shape optimization problems. Several new features including two variations of a binning selection algorithm and a gene-space transformation procedure are included. The genetic algorithm is suitable for finding pareto optimal solutions in search spaces that are defined by any number of genes and that contain any number of local extrema. A new masking array capability is included allowing any gene or gene subset to be eliminated as decision variables from the design space. This allows determination of the effect of a single gene or gene subset on the pareto optimal solution. Results indicate that the genetic algorithm optimization approach is flexible in application and reliable. The binning selection algorithms generally provide pareto front quality enhancements and moderate convergence efficiency improvements for most of the problems solved.

  5. Reasoning about Function Objects

    NASA Astrophysics Data System (ADS)

    Nordio, Martin; Calcagno, Cristiano; Meyer, Bertrand; Müller, Peter; Tschannen, Julian

    Modern object-oriented languages support higher-order implementations through function objects such as delegates in C#, agents in Eiffel, or closures in Scala. Function objects bring a new level of abstraction to the object-oriented programming model, and require a comparable extension to specification and verification techniques. We introduce a verification methodology that extends function objects with auxiliary side-effect free (pure) methods to model logical artifacts: preconditions, postconditions and modifies clauses. These pure methods can be used to specify client code abstractly, that is, independently from specific instantiations of the function objects. To demonstrate the feasibility of our approach, we have implemented an automatic prover, which verifies several non-trivial examples.

  6. Fourier functional analysis for unsteady aerodynamic modeling

    NASA Technical Reports Server (NTRS)

    Lan, C. Edward; Chin, Suei

    1991-01-01

    A method based on Fourier analysis is developed to analyze the force and moment data obtained in large amplitude forced oscillation tests at high angles of attack. The aerodynamic models for normal force, lift, drag, and pitching moment coefficients are built up from a set of aerodynamic responses to harmonic motions at different frequencies. Based on the aerodynamic models of harmonic data, the indicial responses are formed. The final expressions for the models involve time integrals of the indicial type advocated by Tobak and Schiff. Results from linear two- and three-dimensional unsteady aerodynamic theories as well as test data for a 70-degree delta wing are used to verify the models. It is shown that the present modeling method is accurate in producing the aerodynamic responses to harmonic motions and the ramp type motions. The model also produces correct trend for a 70-degree delta wing in harmonic motion with different mean angles-of-attack. However, the current model cannot be used to extrapolate data to higher angles-of-attack than that of the harmonic motions which form the aerodynamic model. For linear ramp motions, a special method is used to calculate the corresponding frequency and phase angle at a given time. The calculated results from modeling show a higher lift peak for linear ramp motion than for harmonic ramp motion. The current model also shows reasonably good results for the lift responses at different angles of attack.

  7. A universal functional object

    NASA Technical Reports Server (NTRS)

    Roth, J. P.

    1972-01-01

    A scheme is presented for realizing any function, combinational or sequential, in a single universal function scheme, termed the universal function object UF. This scheme is addressed to the problem of the proliferation of the number of parts (cards, chips) necessary for conventional implementation in an LSI technology of a computer system. The UF implementation will use about ten times more circuits than a conventional implementation regardless of the size of the design. The UF approach also includes general-purpose spares for failing circuits. The procedure could be used both at manufacture to increase yields, as well as to achieve automatic repair.

  8. Basis Function Approximation of Transonic Aerodynamic Influence Coefficient Matrix

    NASA Technical Reports Server (NTRS)

    Li, Wesley W.; Pak, Chan-gi

    2011-01-01

    A technique for approximating the modal aerodynamic influence coefficients matrices by using basis functions has been developed and validated. An application of the resulting approximated modal aerodynamic influence coefficients matrix for a flutter analysis in transonic speed regime has been demonstrated. This methodology can be applied to the unsteady subsonic, transonic, and supersonic aerodynamics. The method requires the unsteady aerodynamics in frequency-domain. The flutter solution can be found by the classic methods, such as rational function approximation, k, p-k, p, root-locus et cetera. The unsteady aeroelastic analysis for design optimization using unsteady transonic aerodynamic approximation is being demonstrated using the ZAERO flutter solver (ZONA Technology Incorporated, Scottsdale, Arizona). The technique presented has been shown to offer consistent flutter speed prediction on an aerostructures test wing 2 configuration with negligible loss in precision in transonic speed regime. These results may have practical significance in the analysis of aircraft aeroelastic calculation and could lead to a more efficient design optimization cycle.

  9. Plasma Flowfields Around Low Earth Orbit Objects: Aerodynamics to Underpin Orbit Predictions

    NASA Astrophysics Data System (ADS)

    Capon, Christopher; Boyce, Russell; Brown, Melrose

    2016-07-01

    Interactions between orbiting bodies and the charged space environment are complex. The large variation in passive body parameters e.g. size, geometry and materials, makes the plasma-body interaction in Low Earth Orbit (LEO) a region rich in fundamental physical phenomena. The aerodynamic interaction of LEO orbiting bodies with the neutral environment constitutes the largest non-conservative force on the body. However in general, study of the LEO plasma-body interaction has not been concerned with external flow physics, but rather with the effects on surface charging. The impact of ionospheric flow physics on the forces on space debris (and active objects) is not well understood. The work presented here investigates the contribution that plasma-body interactions have on the flow structure and hence on the total atmospheric force vector experienced by a polar orbiting LEO body. This work applies a hybrid Particle-in-Cell (PIC) - Direct Simulation Monte Carlo (DSMC) code, pdFoam, to self-consistently model the electrostatic flowfield about a cylinder with a uniform, fixed surface potential. Flow conditions are representative of the mean conditions experienced by the Earth Observing Satellite (EOS) based on the International Reference Ionosphere model (IRI-86). The electron distribution function is represented by a non-linear Boltzmann electron fluid and ion gas-surface interactions are assumed to be that of a neutralising, conducting, thermally accommodating solid wall with diffuse reflections. The variation in flowfield and aerodynamic properties with surface potential at a fixed flow condition is investigated, and insight into the relative contributions of charged and neutral species to the flow physics experienced by a LEO orbiting body is provided. This in turn is intended to help improve the fidelity of physics-based orbit predictions for space debris and other near-Earth space objects.

  10. Basis Function Approximation of Transonic Aerodynamic Influence Coefficient Matrix

    NASA Technical Reports Server (NTRS)

    Li, Wesley Waisang; Pak, Chan-Gi

    2010-01-01

    A technique for approximating the modal aerodynamic influence coefficients [AIC] matrices by using basis functions has been developed and validated. An application of the resulting approximated modal AIC matrix for a flutter analysis in transonic speed regime has been demonstrated. This methodology can be applied to the unsteady subsonic, transonic and supersonic aerodynamics. The method requires the unsteady aerodynamics in frequency-domain. The flutter solution can be found by the classic methods, such as rational function approximation, k, p-k, p, root-locus et cetera. The unsteady aeroelastic analysis for design optimization using unsteady transonic aerodynamic approximation is being demonstrated using the ZAERO(TradeMark) flutter solver (ZONA Technology Incorporated, Scottsdale, Arizona). The technique presented has been shown to offer consistent flutter speed prediction on an aerostructures test wing [ATW] 2 configuration with negligible loss in precision in transonic speed regime. These results may have practical significance in the analysis of aircraft aeroelastic calculation and could lead to a more efficient design optimization cycle

  11. Introduction to Generalized Functions with Applications in Aerodynamics and Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Farassat, F.

    1994-01-01

    Generalized functions have many applications in science and engineering. One useful aspect is that discontinuous functions can be handled as easily as continuous or differentiable functions and provide a powerful tool in formulating and solving many problems of aerodynamics and acoustics. Furthermore, generalized function theory elucidates and unifies many ad hoc mathematical approaches used by engineers and scientists. We define generalized functions as continuous linear functionals on the space of infinitely differentiable functions with compact support, then introduce the concept of generalized differentiation. Generalized differentiation is the most important concept in generalized function theory and the applications we present utilize mainly this concept. First, some results of classical analysis, are derived with the generalized function theory. Other applications of the generalized function theory in aerodynamics discussed here are the derivations of general transport theorems for deriving governing equations of fluid mechanics, the interpretation of the finite part of divergent integrals, the derivation of the Oswatitsch integral equation of transonic flow, and the analysis of velocity field discontinuities as sources of vorticity. Applications in aeroacoustics include the derivation of the Kirchhoff formula for moving surfaces, the noise from moving surfaces, and shock noise source strength based on the Ffowcs Williams-Hawkings equation.

  12. Experimental characterization of high speed centrifugal compressor aerodynamic forcing functions

    NASA Astrophysics Data System (ADS)

    Gallier, Kirk

    The most common and costly unexpected post-development gas turbine engine reliability issue is blade failure due to High Cycle Fatigue (HCF). HCF in centrifugal compressors is a coupled nonlinear fluid-structure problem for which understanding of the phenomenological root causes is incomplete. The complex physics of this problem provides significant challenges for Computational Fluid Dynamics (CFD) techniques. Furthermore, the available literature fails to address the flow field associated with the diffuser potential field, a primary cause of forced impeller vibration. Because of the serious nature of HCF, the inadequacy of current design approaches to predict HCF, and the fundamental lack of benchmark experiments to advance the design practices, there exists a need to build a database of information specific to the nature of the diffuser generated forcing function as a foundation for understanding flow induced blade vibratory failure. The specific aim of this research is to address the fundamental nature of the unsteady aerodynamic interaction phenomena inherent in high-speed centrifugal compressors wherein the impeller exit flow field is dynamically modulated by the vaned diffuser potential field or shock structure. The understanding of this unsteady aerodynamic interaction is fundamental to characterizing the impeller forcing function. Unsteady static pressure measurement at several radial and circumferential locations in the vaneless space offer a depiction of pressure field radial decay, circumferential variation and temporal fluctuation. These pressure measurements are coupled with high density, full field measurement of the velocity field within the diffuser vaneless space at multiple spanwise positions. The velocity field and unsteady pressure field are shown to be intimately linked. A strong momentum gradient exiting the impeller is shown to extend well across the vaneless space and interact with the diffuser vane leading edge. The deterministic unsteady

  13. Aerodynamic Indicial Functions and Their Use in Aeroelastic Formulation of Lifting Surfaces

    NASA Technical Reports Server (NTRS)

    Marzocca, Piergiovanni; Librescu, Liviu; Silva, Walter A.

    2000-01-01

    An investigation related to the use of linear indicial functions in the time and frequency domains, enabling one to derive the proper aerodynamic loads as to study the subcritical response and flutter of swept lifting surfaces, respectively, of the open/closed loop aeroelastic system is presented. The expressions of the lift and aerodynamic moment in the frequency domain are given in terms of the Theodorsen's function, while, in the time domain, these are obtained directly with the help of the Wagner's function. Closed form solutions of aerodynamic derivatives are obtained, graphical representations are supplied and conclusions and prospects for further developments are outlined.

  14. NREL Unsteady Aerodynamics Experiment phase 3 test objectives and preliminary results

    SciTech Connect

    Simms, D.A.; Fingersh, L.J.; Butterfield, C.P.

    1995-09-01

    The United States Department of Energy and the National Renewable Energy Laboratory (NREL) are conducting research to improve a wind turbine technology. One program, the Combined Experiment, has focused on making measurements needed to understand aerodynamic and structural responses of horizontal-axis wind turbines (HAWT). A new phase of this program, the Unsteady Aerodynamics Experiment, will focus on quantifying unsteady aerodynamic phenomena prevalent install controlled HAWTs. Optimally twisted blades and innovative data acquisition systems will be used in these tests. data can now be acquired and viewed interactively during turbine operations. This paper describes the Unsteady Aerodynamics Experiment and highlights planned future research activities.

  15. Cross-spectral recognition method of bridge deck aerodynamic admittance function

    NASA Astrophysics Data System (ADS)

    Zhao, Lin; Ge, Yaojun

    2015-12-01

    This study proposes a new identification algorithm about the admittance function, which can estimate the full set of six aerodynamic admittance functions considering cross power spectral density functions about the forces and the turbulence components. The method was first numerically validated through Monte Carlo simulations, and then adopted to estimate the aerodynamic admittance of a streamlined bridge deck. The identification method was further validated through a comparison between the numerical calculation and wind tunnel tests on a moving bridge section.

  16. Modeling the High Speed Research Cycle 2B Longitudinal Aerodynamic Database Using Multivariate Orthogonal Functions

    NASA Technical Reports Server (NTRS)

    Morelli, E. A.; Proffitt, M. S.

    1999-01-01

    The data for longitudinal non-dimensional, aerodynamic coefficients in the High Speed Research Cycle 2B aerodynamic database were modeled using polynomial expressions identified with an orthogonal function modeling technique. The discrepancy between the tabular aerodynamic data and the polynomial models was tested and shown to be less than 15 percent for drag, lift, and pitching moment coefficients over the entire flight envelope. Most of this discrepancy was traced to smoothing local measurement noise and to the omission of mass case 5 data in the modeling process. A simulation check case showed that the polynomial models provided a compact and accurate representation of the nonlinear aerodynamic dependencies contained in the HSR Cycle 2B tabular aerodynamic database.

  17. Nonlinear programming extensions to rational function approximation methods for unsteady aerodynamic forces

    NASA Technical Reports Server (NTRS)

    Tiffany, Sherwood H.; Adams, William M., Jr.

    1988-01-01

    The approximation of unsteady generalized aerodynamic forces in the equations of motion of a flexible aircraft are discussed. Two methods of formulating these approximations are extended to include the same flexibility in constraining the approximations and the same methodology in optimizing nonlinear parameters as another currently used extended least-squares method. Optimal selection of nonlinear parameters is made in each of the three methods by use of the same nonlinear, nongradient optimizer. The objective of the nonlinear optimization is to obtain rational approximations to the unsteady aerodynamics whose state-space realization is lower order than that required when no optimization of the nonlinear terms is performed. The free linear parameters are determined using the least-squares matrix techniques of a Lagrange multiplier formulation of an objective function which incorporates selected linear equality constraints. State-space mathematical models resulting from different approaches are described and results are presented that show comparative evaluations from application of each of the extended methods to a numerical example.

  18. Influence of Reynolds Number on Multi-Objective Aerodynamic Design of a Wind Turbine Blade.

    PubMed

    Ge, Mingwei; Fang, Le; Tian, De

    2015-01-01

    At present, the radius of wind turbine rotors ranges from several meters to one hundred meters, or even more, which extends Reynolds number of the airfoil profile from the order of 105 to 107. Taking the blade for 3MW wind turbines as an example, the influence of Reynolds number on the aerodynamic design of a wind turbine blade is studied. To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP). It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number. At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP. If a wind turbine blade is designed by using an airfoil database with a mismatched Reynolds number from the actual one, both the load and Cpopt//AEP will be incorrectly estimated to some extent. In some cases, the assessment error attributed to Reynolds number is quite significant, which may bring unexpected risks to the earnings and safety of a wind power project. PMID:26528815

  19. Influence of Reynolds Number on Multi-Objective Aerodynamic Design of a Wind Turbine Blade

    PubMed Central

    Ge, Mingwei; Fang, Le; Tian, De

    2015-01-01

    At present, the radius of wind turbine rotors ranges from several meters to one hundred meters, or even more, which extends Reynolds number of the airfoil profile from the order of 105 to 107. Taking the blade for 3MW wind turbines as an example, the influence of Reynolds number on the aerodynamic design of a wind turbine blade is studied. To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP). It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number. At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP. If a wind turbine blade is designed by using an airfoil database with a mismatched Reynolds number from the actual one, both the load and Cpopt//AEP will be incorrectly estimated to some extent. In some cases, the assessment error attributed to Reynolds number is quite significant, which may bring unexpected risks to the earnings and safety of a wind power project. PMID:26528815

  20. Parallel computing of overset grids for aerodynamic problems with moving objects

    NASA Astrophysics Data System (ADS)

    Prewitt, Nathan Coleman

    When a store is dropped from a military aircraft at high subsonic, transonic, or supersonic speeds, the aerodynamic forces and moments acting on the store can be sufficient to send the store back into contact with the aircraft. Therefore, store separation analysis is used to certify the safety of any proposed drop. Time accurate computational fluid dynamics (CFD) offers the option of calculating store separation trajectories from first principles. In the Chimera grid scheme, a set of independent, overlapping, structured grids are used to decompose the domain of interest. This allows the use of efficient structured grid flow solvers and associated boundary conditions, and allows for grid motion without stretching or regridding. However, these advantages are gained in exchange for the requirement to establish communication links between the overlapping grids via a process referred to as "grid assembly." Relatively little work has been done to use parallel computing for time accurate, moving body problems. Thus, new techniques are presented for the parallel implementation of the assembly of overset, Chimera grids. This work is based on the grid assembly function defined in the Beggar code, currently under development at Eglin Air Force Base, FL. The parallel performance of each implementation is analyzed and equations are presented for estimating the parallel speedup. Each successive implementation attacks the weaknesses of the previous implementation in an effort to improve the parallel performance. The first implementation achieves the solution of moving body problems on multiple processors with minimum code changes. The second implementation improves the parallel performance by hiding the execution time of the grid assembly function behind the execution time of the flow solver. The third implementation uses coarse grain data decomposition to reduce the execution time of the grid assembly function. The final implementation demonstrates the fine grain decomposition

  1. Algorithm for determining the aerodynamic characteristics of a freely flying object from discrete data of ballistic experiment. Part 2

    NASA Astrophysics Data System (ADS)

    Bobashev, S. V.; Mende, N. P.; Popov, P. A.; Sakharov, V. A.; Berdnikov, V. A.; Viktorov, V. A.; Oseeva, S. I.; Sadchikov, G. D.

    2009-04-01

    In part 1 of this paper, an algorithm for numerically solving the inverse problem of motion of a solid through the atmosphere is described that constitutes the basis for identifying the aerodynamic characteristics of an object from trajectory data and the respective identification procedure is presented. In part 2, methods evaluating the significance of desired parameters and adequacy of a mathematical model of motion, approaches to metrological certification of experimental equipment, and results of testing the algorithm are discussed.

  2. Multi Objective Aerodynamic Optimization Using Parallel Nash Evolutionary/deterministic Hybrid Algorithms

    NASA Astrophysics Data System (ADS)

    Tang, Zhili

    2016-06-01

    This paper solved aerodynamic drag reduction of transport wing fuselage configuration in transonic regime by using a parallel Nash evolutionary/deterministic hybrid optimization algorithm. Two sets of parameters are used, namely globally and locally. It is shown that optimizing separately local and global parameters by using Nash algorithms is far more efficient than considering these variables as a whole.

  3. Forcing function effects on unsteady aerodynamic gust response. I - Forcing functions

    NASA Technical Reports Server (NTRS)

    Henderson, Gregory H.; Fleeter, Sanford

    1992-01-01

    The paper investigates the fundamental gust modeling assumption on the basis of a series of experiments performed in the Purdue Annular Cascade Research Facility. The measured unsteady flow fields are compared to linear-theory gust requirements. The perforated plate forcing functions closely resemble linear-theory forcing functions, with the static pressure fluctuations small and the periodic velocity vectors parallel to the downstream mean-relative flow angle over the entire periodic cycle. The airfoil forcing functions exhibit characteristics far from linear-theory gusts, with the alignment of the velocity vectors and the static pressure fluctuation amplitudes dependent on the rotor-loading condition, rotor solidity, and the inlet mean-relative flow angle. It is shown that airfoil wakes, both compressor and turbine, cannot be modeled with the boundary conditions of current state-of-the-art linear unsteady aerodynamic theory.

  4. Aerodynamic parameter estimation via Fourier modulating function techniques

    NASA Technical Reports Server (NTRS)

    Pearson, A. E.

    1995-01-01

    Parameter estimation algorithms are developed in the frequency domain for systems modeled by input/output ordinary differential equations. The approach is based on Shinbrot's method of moment functionals utilizing Fourier based modulating functions. Assuming white measurement noises for linear multivariable system models, an adaptive weighted least squares algorithm is developed which approximates a maximum likelihood estimate and cannot be biased by unknown initial or boundary conditions in the data owing to a special property attending Shinbrot-type modulating functions. Application is made to perturbation equation modeling of the longitudinal and lateral dynamics of a high performance aircraft using flight-test data. Comparative studies are included which demonstrate potential advantages of the algorithm relative to some well established techniques for parameter identification. Deterministic least squares extensions of the approach are made to the frequency transfer function identification problem for linear systems and to the parameter identification problem for a class of nonlinear-time-varying differential system models.

  5. Adult Roles & Functions. Objective Based Evaluation System.

    ERIC Educational Resources Information Center

    West Virginia State Vocational Curriculum Lab., Cedar Lakes.

    This book of objective-based test items is designed to be used with the Adult Roles and Functions curriculum for a non-laboratory home economic course for grades eleven and twelve. It contains item banks for each cognitive objective in the curriculum. In addition, there is a form for the table of specifications to be developed for each unit. This…

  6. Admitting the Inadmissible: Adjoint Formulation for Incomplete Cost Functionals in Aerodynamic Optimization

    NASA Technical Reports Server (NTRS)

    Arian, Eyal; Salas, Manuel D.

    1997-01-01

    We derive the adjoint equations for problems in aerodynamic optimization which are improperly considered as "inadmissible." For example, a cost functional which depends on the density, rather than on the pressure, is considered "inadmissible" for an optimization problem governed by the Euler equations. We show that for such problems additional terms should be included in the Lagrangian functional when deriving the adjoint equations. These terms are obtained from the restriction of the interior PDE to the control surface. Demonstrations of the explicit derivation of the adjoint equations for "inadmissible" cost functionals are given for the potential, Euler, and Navier-Stokes equations.

  7. Aerodynamic interference effects on tilting proprotor aircraft. [using the Green function method

    NASA Technical Reports Server (NTRS)

    Soohoo, P.; Morino, L.; Noll, R. B.; Ham, N. D.

    1977-01-01

    The Green's function method was used to study tilting proprotor aircraft aerodynamics with particular application to the problem of the mutual interference of the wing-fuselage-tail-rotor wake configuration. While the formulation is valid for fully unsteady rotor aerodynamics, attention was directed to steady state aerodynamics, which was achieved by replacing the rotor with the actuator disk approximation. The use of an actuator disk analysis introduced a mathematical singularity into the formulation; this problem was studied and resolved. The pressure distribution, lift, and pitching moment were obtained for an XV-15 wing-fuselage-tail rotor configuration at various flight conditions. For the flight configurations explored, the effects of the rotor wake interference on the XV-15 tilt rotor aircraft yielded a reduction in the total lift and an increase in the nose-down pitching moment. This method provides an analytical capability that is simple to apply and can be used to investigate fuselage-tail rotor wake interference as well as to explore other rotor design problem areas.

  8. Forcing function effects on unsteady aerodynamic gust response. II - Low solidity airfoil row response

    NASA Technical Reports Server (NTRS)

    Henderson, Gregory H.; Fleeter, Sanford

    1992-01-01

    The paper investigates the fundamental gust modeling assumption on the basis of a series of experiments performed in the Purdue Annular Cascade Research Facility. The unsteady period flow field is generated by rotating flows of perforated plates and airfoil cascades, with the resulting unsteady periodic chordwise pressure response of a downstream low solidity stator row determined by miniature pressure transducers embedded within selected airfoils. When the forcing function exhibited the characteristics of a linear-theory gust, the resulting response on the downstream stator airfoils was in excellent agreement with the linear-theory models. When the forcing function did not exhibit linear-theory gust characteristics, the resulting unsteady aerodynamic response of the downstream stators was much more complex and correlated poorly with the linear-theory gust predictions. It is shown that the forcing function generator significantly affects the resulting gust response, with the complexity of the response characteristics increasing from the perforated-plate to the airfoil-cascade forcing functions.

  9. An introduction to generalized functions with some applications in aerodynamics and aeroacoustics

    NASA Technical Reports Server (NTRS)

    Farassat, F.

    1994-01-01

    In this paper, we start with the definition of generalized functions as continuous linear functionals on the space of infinitely differentiable functions with compact support. The concept of generalization differentiation is introduced next. This is the most important concept in generalized function theory and the applications we present utilize mainly this concept. First, some of the results of classical analysis, such as Leibniz rule of differentiation under the integral sign and the divergence theorem, are derived using the generalized function theory. It is shown that the divergence theorem remains valid for discontinuous vector fields provided that the derivatives are all viewed as generalized derivatives. This implies that all conservation laws of fluid mechanics are valid as they stand for discontinuous fields with all derivatives treated as generalized deriatives. Once these derivatives are written as ordinary derivatives and jumps in the field parameters across discontinuities, the jump conditions can be easily found. For example, the unsteady shock jump conditions can be derived from mass and momentum conservation laws. By using a generalized function theory, this derivative becomes trivial. Other applications of the generalized function theory in aerodynamics discussed in this paper are derivation of general transport theorems for deriving governing equations of fluid mechanics, the interpretation of finite part of divergent integrals, derivation of Oswatiitsch integral equation of transonic flow, and analysis of velocity field discontinuities as sources of vorticity. Applications in aeroacoustics presented here include the derivation of the Kirchoff formula for moving surfaces,the noise from moving surfaces, and shock noise source strength based on the Ffowcs Williams-Hawkings equation.

  10. The Cranked Arrow Wing Aerodynamics Project (CAWAP) and its Extension to the International Community as CAWAPI: Objectives and Overview

    NASA Technical Reports Server (NTRS)

    Lamar, John E.; Obara, Clifford J.

    2009-01-01

    This paper provides a brief history of the F-16XL-1 aircraft, its role in the High Speed Research (HSR) program and how it was morphed into the Cranked Arrow Wing Aerodynamics Project (CAWAP). Various flight, wind-tunnel and Computational Fluid Dynamics (CFD) data sets were generated during the CAWAP. These unique and open flight datasets for surface pressures, boundary-layer profiles and skin-friction distributions, along with surface flow data, are described and sample data comparisons given. This is followed by a description of how the project became internationalized to be known as Cranked Arrow Wing Aerodynamics Project International (CAWAPI) and is concluded by an introduction to the results of a 5-year CFD predictive study of data.

  11. THE OBJECT-PRESERVING FUNCTION OF SADOMASOCHISM.

    PubMed

    Grossman, Lee

    2015-07-01

    The terms sadism, masochism, and sadomasochism seem to have become increasingly, if loosely, associated with aggression in psychoanalytic discourse. This is due in part to the fact that Freud's changing ideas generated confusion about the relative contributions of libido and aggression. The author reviews Freud's variable usage and offers a clinical vignette to illustrate the importance of noticing how sadomasochism may maintain a tie to the object by controlling it. The author offers a developmental speculation for the role reversibility typical of sadomasochistic manifestations. He closes with a comment on the role of sadomasochistic aims in adult sexual perversion. PMID:26198604

  12. Object Function Facilitates Infants' Object Individuation in a Manual Search Task

    ERIC Educational Resources Information Center

    Kingo, Osman S.; Krojgaard, Peter

    2012-01-01

    This study investigates the importance of object function (action-object-outcome relations) on object individuation in infancy. Five experiments examined the ability of 9.5- and 12-month-old infants to individuate simple geometric objects in a manual search design. Experiments 1 through 4 (12-month-olds, N = 128) provided several combinations of…

  13. Outcome of resonant voice therapy for female teachers with voice disorders: perceptual, physiological, acoustic, aerodynamic, and functional measurements.

    PubMed

    Chen, Sheng Hwa; Hsiao, Tzu-Yu; Hsiao, Li-Chun; Chung, Yu-Mei; Chiang, Shu-Chiung

    2007-07-01

    Teachers have a high percentage of voice problems. For voice disordered teachers, resonant voice therapy is hypothesized to reduce voice problems. No research has been done on the physiological, acoustic, and aerodynamic effects of resonant voice therapy for school teachers. The purpose of this study is to investigate resonant voice therapy outcome from perceptual, physiological, acoustic, aerodynamic, and functional aspects for female teachers with voice disorders. A prospective study was designed for this research. The research subjects were 24 female teachers in Taipei. All subjects received resonant voice therapy in groups of 4 subjects, 90 minutes per session, and 1 session per week for 8 weeks. The outcome of resonant voice therapy was assessed from auditory perceptual judgment, videostroboscopic examination, acoustic measurements, aerodynamic measurements, and functional measurements before and after therapy. After therapy the severity of roughness, strain, monotone, resonance, hard attack, and glottal fry in auditory perceptual judgments, the severity of vocal fold pathology, mucosal wave, amplitude, and vocal fold closure in videostroboscopic examinations, phonation threshold pressure, and the score of physical scale in the Voice Handicap Index were significantly reduced. The speaking Fo, maximum range of speaking Fo, and maximum range of speaking intensity were significantly increased after therapy. No significant change was found in perturbation and breathiness measurements after therapy. Resonant voice therapy is effective for school teachers and is suggested as one of the therapy approaches in clinics for this population. PMID:16581227

  14. Conflict between object structural and functional affordances in peripersonal space.

    PubMed

    Kalénine, Solène; Wamain, Yannick; Decroix, Jérémy; Coello, Yann

    2016-10-01

    Recent studies indicate that competition between conflicting action representations slows down planning of object-directed actions. The present study aims to assess whether similar conflict effects exist during manipulable object perception. Twenty-six young adults performed reach-to-grasp and semantic judgements on conflictual objects (with competing structural and functional gestures) and non-conflictual objects (with similar structural and functional gestures) presented at difference distances in a 3D virtual environment. Results highlight a space-dependent conflict between structural and functional affordances. Perceptual judgments on conflictual objects were slower that perceptual judgments on non-conflictual objects, but only when objects were presented within reach. Findings demonstrate that competition between structural and functional affordances during object perception induces a processing cost, and further show that object position in space can bias affordance competition. PMID:27327864

  15. Strain measurement of objects subjected to aerodynamic heating using digital image correlation: experimental design and preliminary results.

    PubMed

    Pan, Bing; Jiang, Tianyun; Wu, Dafang

    2014-11-01

    In thermomechanical testing of hypersonic materials and structures, direct observation and quantitative strain measurement of the front surface of a test specimen directly exposed to severe aerodynamic heating has been considered as a very challenging task. In this work, a novel quartz infrared heating device with an observation window is designed to reproduce the transient thermal environment experienced by hypersonic vehicles. The specially designed experimental system allows the capture of test article's surface images at various temperatures using an optical system outfitted with a bandpass filter. The captured images are post-processed by digital image correlation to extract full-field thermal deformation. To verify the viability and accuracy of the established system, thermal strains of a chromiumnickel austenite stainless steel sample heated from room temperature up to 600 °C were determined. The preliminary results indicate that the air disturbance between the camera and the specimen due to heat haze induces apparent distortions in the recorded images and large errors in the measured strains, but the average values of the measured strains are accurate enough. Limitations and further improvements of the proposed technique are discussed. PMID:25430144

  16. Preschoolers' and Adults' Reliance on Object Shape and Object Function for Lexical Extension.

    ERIC Educational Resources Information Center

    Graham, Susan A.; Williams, Lisa D.; Huber, Joelene F.

    1999-01-01

    Three experiments investigated the developmental progression of reliance on object function versus object shape to extend novel words among 3- and 5-year olds and adults. Findings indicated that children focused on shape, whereas adults focused on function when extending novel words, suggesting a developmental change in the consideration of these…

  17. Details of insect wing design and deformation enhance aerodynamic function and flight efficiency.

    PubMed

    Young, John; Walker, Simon M; Bomphrey, Richard J; Taylor, Graham K; Thomas, Adrian L R

    2009-09-18

    Insect wings are complex structures that deform dramatically in flight. We analyzed the aerodynamic consequences of wing deformation in locusts using a three-dimensional computational fluid dynamics simulation based on detailed wing kinematics. We validated the simulation against smoke visualizations and digital particle image velocimetry on real locusts. We then used the validated model to explore the effects of wing topography and deformation, first by removing camber while keeping the same time-varying twist distribution, and second by removing camber and spanwise twist. The full-fidelity model achieved greater power economy than the uncambered model, which performed better than the untwisted model, showing that the details of insect wing topography and deformation are important aerodynamically. Such details are likely to be important in engineering applications of flapping flight. PMID:19762645

  18. Missile aerodynamics

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.

    1988-01-01

    The fundamental aerodynamics of slender bodies is examined in the reprint edition of an introductory textbook originally published in 1960. Chapters are devoted to the formulas commonly used in missile aerodynamics; slender-body theory at supersonic and subsonic speeds; vortices in viscid and inviscid flow; wing-body interference; downwash, sidewash, and the wake; wing-tail interference; aerodynamic controls; pressure foredrag, base drag, and skin friction; and stability derivatives. Diagrams, graphs, tables of terms and formulas are provided.

  19. Aerodynamic simulation

    SciTech Connect

    Not Available

    1993-01-01

    In this article two integral computational fluid dynamics methods for steady-state and transient vehicle aerodynamic simulations are described using a Chevrolet Corvette ZR-1 surface panel model. In the last decade, road-vehicle aerodynamics have become an important design consideration. Originally, the design of low-drag shapes was given high priority due to worldwide fuel shortages that occurred in the mid-seventies. More recently, there has been increased interest in the role aerodynamics play in vehicle stability and passenger safety. Consequently, transient aerodynamics and the aerodynamics of vehicle in yaw have become important issues at the design stage. While there has been tremendous progress in Navier-Stokes methodology in the last few years, the physics of bluff-body aerodynamics are still very difficult to model correctly. Moreover, the computational effort to perform Navier-Stokes simulations from the geometric stage to complete flow solutions requires much computer time and impacts the design cycle time. In the short run, therefore, simpler methods must be used for such complicated problems. Here, two methods are described for the simulation of steady-state and transient vehicle aerodynamics.

  20. Aerodynamic Synthesis of Biocompatible Matrices and their Functionalization by Nanoparticles Obtained by the Method of Laser Ablation

    NASA Astrophysics Data System (ADS)

    Bol'basov, E. N.; Lapin, I. N.; Tverdokhlebov, S. I.; Svetlichnyi, V. A.

    2014-07-01

    For applications in tissue engineering, three-dimensional biodegradable polymeric matrices, whose surface is functionalized by nanoparticles obtained in the liquid phase by the method of laser ablation from bulk metal (Ag or Zn) targets, are synthesized by the method of aerodynamic synthesis from a solution of poly-l-lactide acid. Their properties are investigated. It is demonstrated that the matrices represent a very porous spatial fibrous structure consisting of polymorphic fibers with diameters from 0.25 to 2.5 μm. It is established that functional coatings consisting of agglomerates of semiconductor (ZnO) or metal (Ag) nanoparticles can be produced on the surface of structural matrix elements by repeated matrix impregnation.

  1. Career Exploration Program: A Composite Systematic Functional Objective Model.

    ERIC Educational Resources Information Center

    Mohamed, Othman

    The composite systematic functional objective career exploration program model integrates various career development theoretical approaches. These approaches emphasize self-concept, life values, personality, the environment, and academic achievement and training as separate functions in explaining career development. Current social development in…

  2. In vivo recording of aerodynamic force with an aerodynamic force platform: from drones to birds.

    PubMed

    Lentink, David; Haselsteiner, Andreas F; Ingersoll, Rivers

    2015-03-01

    Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these forces directly during free flight. Such in vivo recordings in freely behaving animals are essential to better understand the precise aerodynamic function of their flapping wings, in particular during the downstroke versus upstroke. Here, we demonstrate a new aerodynamic force platform (AFP) for non-intrusive aerodynamic force measurement in freely flying animals and robots. The platform encloses the animal or object that generates fluid force with a physical control surface, which mechanically integrates the net aerodynamic force that is transferred to the earth. Using a straightforward analytical solution of the Navier-Stokes equation, we verified that the method is accurate. We subsequently validated the method with a quadcopter that is suspended in the AFP and generates unsteady thrust profiles. These independent measurements confirm that the AFP is indeed accurate. We demonstrate the effectiveness of the AFP by studying aerodynamic weight support of a freely flying bird in vivo. These measurements confirm earlier findings based on kinematics and flow measurements, which suggest that the avian downstroke, not the upstroke, is primarily responsible for body weight support during take-off and landing. PMID:25589565

  3. In vivo recording of aerodynamic force with an aerodynamic force platform: from drones to birds

    PubMed Central

    Lentink, David; Haselsteiner, Andreas F.; Ingersoll, Rivers

    2015-01-01

    Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these forces directly during free flight. Such in vivo recordings in freely behaving animals are essential to better understand the precise aerodynamic function of their flapping wings, in particular during the downstroke versus upstroke. Here, we demonstrate a new aerodynamic force platform (AFP) for non-intrusive aerodynamic force measurement in freely flying animals and robots. The platform encloses the animal or object that generates fluid force with a physical control surface, which mechanically integrates the net aerodynamic force that is transferred to the earth. Using a straightforward analytical solution of the Navier–Stokes equation, we verified that the method is accurate. We subsequently validated the method with a quadcopter that is suspended in the AFP and generates unsteady thrust profiles. These independent measurements confirm that the AFP is indeed accurate. We demonstrate the effectiveness of the AFP by studying aerodynamic weight support of a freely flying bird in vivo. These measurements confirm earlier findings based on kinematics and flow measurements, which suggest that the avian downstroke, not the upstroke, is primarily responsible for body weight support during take-off and landing. PMID:25589565

  4. Aerodynamic Design Using Neural Networks

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan; Madavan, Nateri K.

    2003-01-01

    The design of aerodynamic components of aircraft, such as wings or engines, involves a process of obtaining the most optimal component shape that can deliver the desired level of component performance, subject to various constraints, e.g., total weight or cost, that the component must satisfy. Aerodynamic design can thus be formulated as an optimization problem that involves the minimization of an objective function subject to constraints. A new aerodynamic design optimization procedure based on neural networks and response surface methodology (RSM) incorporates the advantages of both traditional RSM and neural networks. The procedure uses a strategy, denoted parameter-based partitioning of the design space, to construct a sequence of response surfaces based on both neural networks and polynomial fits to traverse the design space in search of the optimal solution. Some desirable characteristics of the new design optimization procedure include the ability to handle a variety of design objectives, easily impose constraints, and incorporate design guidelines and rules of thumb. It provides an infrastructure for variable fidelity analysis and reduces the cost of computation by using less-expensive, lower fidelity simulations in the early stages of the design evolution. The initial or starting design can be far from optimal. The procedure is easy and economical to use in large-dimensional design space and can be used to perform design tradeoff studies rapidly. Designs involving multiple disciplines can also be optimized. Some practical applications of the design procedure that have demonstrated some of its capabilities include the inverse design of an optimal turbine airfoil starting from a generic shape and the redesign of transonic turbines to improve their unsteady aerodynamic characteristics.

  5. Classical methods for interpreting objective function minimization as intelligent inference

    SciTech Connect

    Golden, R.M.

    1996-12-31

    Most recognition algorithms and neural networks can be formally viewed as seeking a minimum value of an appropriate objective function during either classification or learning phases. The goal of this paper is to argue that in order to show a recognition algorithm is making intelligent inferences, it is not sufficient to show that the recognition algorithm is computing (or trying to compute) the global minimum of some objective function. One must explicitly define a {open_quotes}relational system{close_quotes} for the recognition algorithm or neural network which identifies the: (i) sample space, (ii) the relevant sigmafield of events generated by the sample space, and (iii) the {open_quotes}relation{close_quotes} for that relational system. Only when such a {open_quotes}relational system{close_quotes} is properly defined, is it possible to formally establish the sense in which computing the global minimum of an objective function is an intelligent, inference.

  6. Neurocognitive insight and objective cognitive functioning in schizophrenia.

    PubMed

    Burton, Cynthia Z; Harvey, Philip D; Patterson, Thomas L; Twamley, Elizabeth W

    2016-03-01

    Neurocognitive impairment is a core component of schizophrenia affecting everyday functioning; the extent to which individuals with schizophrenia show awareness of neurocognitive impairment (neurocognitive insight) is unclear. This study investigated neurocognitive insight and examined the cross-sectional relationships between neurocognitive insight and objective neurocognition and functional capacity performance in a large outpatient sample. 214 participants with schizophrenia-spectrum disorders completed measures of neurocognition, functional capacity, and self-reported neurocognitive problems. Latent profile analysis classified participants with regard to neuropsychological performance and self-report of neurocognitive problems. The resulting classes were then compared on executive functioning performance, functional capacity performance, and psychiatric symptom severity. More than three quarters of the sample demonstrated objective neurocognitive impairment (global deficit score≥0.50). Among the participants with neurocognitive impairment, 54% were classified as having "impaired" neurocognitive insight (i.e., reporting few neurocognitive problems despite having objective neurocognitive impairment). Participants with impaired vs. intact neurocognitive insight did not differ on executive functioning measures or measures of functional capacity or negative symptom severity, but those with intact neurocognitive insight reported higher levels of positive and depressive symptoms. A substantial portion of individuals with schizophrenia and objectively measured neurocognitive dysfunction appear unaware of their deficits. Patient self-report of neurocognitive problems, therefore, is not likely to reliably assess neurocognition. Difficulty self-identifying neurocognitive impairment appears to be unrelated to executive functioning, negative symptoms, and functional capacity. For those with intact neurocognitive insight, improving depressive and psychotic symptoms may be

  7. Objective and automated measurement of dynamic vision functions

    NASA Technical Reports Server (NTRS)

    Flom, M. C.; Adams, A. J.

    1976-01-01

    A phoria stimulus array and electro-oculographic (EOG) arrangements for measuring motor and sensory responses of subjects subjected to stress or drug conditions are described, along with experimental procedures. Heterophoria (as oculomotor function) and glare recovery time (time required for photochemical and neural recovery after exposure to a flash stimulus) are measured, in research aimed at developing automated objective measurement of dynamic vision functions. Onset of involuntary optokinetic nystagmus in subjects attempting to track moving stripes (while viewing through head-mounted binocular eyepieces) after exposure to glare serves as an objective measure of glare recovery time.

  8. Evolution of the luminosity function of extragalactic objects

    NASA Technical Reports Server (NTRS)

    Petrosian, V.

    1985-01-01

    A nonparametric procedure for determination of the evolution of the luminosity function of extragalactic objects and use of this for prediction of expected redshift and luminosity distribution of objects is described. The relation between this statistical evolution of the population and their physical evolution, such as the variation with cosmological epoch of their luminosity and formation rate is presented. This procedure when applied to a sample of optically selected quasars with redshifts less than two shows that the luminosity function evolves more strongly for higher luminosities, indicating a larger quasar activity at earlier epochs and a more rapid evolution of the objects during their higher luminosity phases. It is also shown that absence of many quasars at redshifts greater than three implies slowing down of this evolution in the conventional cosmological models, perhaps indicating that this is near the epoch of the birth of the quasar (and galaxies).

  9. Entrainment of radio frequency chaff by wind as a function of surface aerodynamic roughness.

    PubMed

    Gillies, John A; Nickling, William G

    2003-02-01

    Radio frequency (RF) chaff (approximately 2-cm x 25-microm diameter aluminum-coated glass silicate cylinders) released by military aircraft during testing and training activities has the potential to become entrained by wind upon settling to the Earth's surface. Once entrained from the surface there is the potential for RF chaff to be abraded and produce PM10 and PM2.5, which are regulated pollutants and pose health concerns. A series of portable wind tunnel tests were carried out to examine the propensity of RF chaff to become entrained by wind by defining the relationship between the threshold friction velocity of RF chaff (u(*t RF chaff)) and aerodynamic roughness (z(o)) of surfaces onto which it may deposit. The test surfaces were of varying roughness including types near the Naval Air Station (NAS), Fallon, NV, where RF chaff is released. The u(*t) of this fibrous material ranged from 0.14 m/sec for a smooth playa to 0.82 m/sec for a rough crusted playa surface with larger cobble-sized (approximately 6-26-cm diameter) rocks rising above the surface. The u(*t RF chaff) is dependent on the z(o) of the surface onto which it falls as well as the physical characteristics of the roughness. The wind regime of Fallon would allow for chaff suspension events to occur should it settle on typical surfaces in the area. However, the wind climatology of this area makes the probability of such events relatively low. PMID:12617294

  10. The functional neuroanatomy of object agnosia: A case study

    PubMed Central

    Konen, Christina S.; Behrmann, Marlene; Nishimura, Mayu; Kastner, Sabine

    2016-01-01

    Summary Cortical re-organization of visual and object representations following neural injury was examined using fMRI and behavioral investigations. We probed the visual responsivity of the ventral visual cortex of an agnosic patient who was impaired at object recognition following a lesion to the right lateral fusiform gyrus. In both hemispheres, retinotopic mapping revealed typical topographic organization and visual activation of early visual cortex. However, visual responses, object-related and -selective responses were reduced in regions immediately surrounding the lesion in the right hemisphere, and also, surprisingly, in corresponding locations in the structurally intact left hemisphere. In contrast, hV4 of the right hemisphere showed expanded response properties. These findings indicate that the right lateral fusiform gyrus is critically involved in object recognition and that an impairment to this region has widespread consequences for remote parts of cortex. Finally, functional neural plasticity is possible even when a cortical lesion is sustained in adulthood. PMID:21745637

  11. Aerodynamic shape optimization using control theory

    NASA Technical Reports Server (NTRS)

    Reuther, James

    1996-01-01

    Aerodynamic shape design has long persisted as a difficult scientific challenge due its highly nonlinear flow physics and daunting geometric complexity. However, with the emergence of Computational Fluid Dynamics (CFD) it has become possible to make accurate predictions of flows which are not dominated by viscous effects. It is thus worthwhile to explore the extension of CFD methods for flow analysis to the treatment of aerodynamic shape design. Two new aerodynamic shape design methods are developed which combine existing CFD technology, optimal control theory, and numerical optimization techniques. Flow analysis methods for the potential flow equation and the Euler equations form the basis of the two respective design methods. In each case, optimal control theory is used to derive the adjoint differential equations, the solution of which provides the necessary gradient information to a numerical optimization method much more efficiently then by conventional finite differencing. Each technique uses a quasi-Newton numerical optimization algorithm to drive an aerodynamic objective function toward a minimum. An analytic grid perturbation method is developed to modify body fitted meshes to accommodate shape changes during the design process. Both Hicks-Henne perturbation functions and B-spline control points are explored as suitable design variables. The new methods prove to be computationally efficient and robust, and can be used for practical airfoil design including geometric and aerodynamic constraints. Objective functions are chosen to allow both inverse design to a target pressure distribution and wave drag minimization. Several design cases are presented for each method illustrating its practicality and efficiency. These include non-lifting and lifting airfoils operating at both subsonic and transonic conditions.

  12. Nozzle Aerodynamic Stability During a Throat Shift

    NASA Technical Reports Server (NTRS)

    Kawecki, Edwin J.; Ribeiro, Gregg L.

    2005-01-01

    An experimental investigation was conducted on the internal aerodynamic stability of a family of two-dimensional (2-D) High Speed Civil Transport (HSCT) nozzle concepts. These nozzles function during takeoff as mixer-ejectors to meet acoustic requirements, and then convert to conventional high-performance convergent-divergent (CD) nozzles at cruise. The transition between takeoff mode and cruise mode results in the aerodynamic throat and the minimum cross-sectional area that controls the engine backpressure shifting location within the nozzle. The stability and steadiness of the nozzle aerodynamics during this so called throat shift process can directly affect the engine aerodynamic stability, and the mechanical design of the nozzle. The objective of the study was to determine if pressure spikes or other perturbations occurred during the throat shift process and, if so, identify the caused mechanisms for the perturbations. The two nozzle concepts modeled in the test program were the fixed chute (FC) and downstream mixer (DSM). These 2-D nozzles differ principally in that the FC has a large over-area between the forward throat and aft throat locations, while the DSM has an over-area of only about 10 percent. The conclusions were that engine mass flow and backpressure can be held constant simultaneously during nozzle throat shifts on this class of nozzles, and mode shifts can be accomplished at a constant mass flow and engine backpressure without upstream pressure perturbations.

  13. Steady, Oscillatory, and Unsteady Subsonic and Supersonic Aerodynamics, production version (SOUSSA-P 1.1). Volume 1: Theoretical manual. [Green function

    NASA Technical Reports Server (NTRS)

    Morino, L.

    1980-01-01

    Recent developments of the Green's function method and the computer program SOUSSA (Steady, Oscillatory, and Unsteady Subsonic and Supersonic Aerodynamics) are reviewed and summarized. Applying the Green's function method to the fully unsteady (transient) potential equation yields an integro-differential-delay equation. With spatial discretization by the finite-element method, this equation is approximated by a set of differential-delay equations in time. Time solution by Laplace transform yields a matrix relating the velocity potential to the normal wash. Premultiplying and postmultiplying by the matrices relating generalized forces to the potential and the normal wash to the generalized coordinates one obtains the matrix of the generalized aerodynamic forces. The frequency and mode-shape dependence of this matrix makes the program SOUSSA useful for multiple frequency and repeated mode-shape evaluations.

  14. A novel objective evaluation method for trunk function

    PubMed Central

    Kinoshita, Kazuaki; Hashimoto, Masashi; Ishida, Kazunari; Yoneda, Yuki; Naka, Yuta; Kitanishi, Hideyuki; Oyagi, Hirotaka; Hoshino, Yuichi; Shibanuma, Nao

    2015-01-01

    [Purpose] To investigate whether an objective evaluation method for trunk function, namely the “trunk righting test”, is reproducible and reliable by testing on different observers (from experienced to beginners) and by confirming the test-retest reliability. [Subjects] Five healthy subjects were evaluated in this correlation study. [Methods] A handheld dynamometer was used in the assessments. The motor task was a trunk righting motion by moving the part with the sensor pad 10 cm outward from the original position. During measurement, the posture was held at maximum effort for 5 s. Measurement was repeated three times. Interexaminer reproducibility was examined in two physical therapists with 1 year experience and one physical therapist with 7 years of experience. The measured values were evaluated for reliability by using intraclass correlation coefficients (ICC 1.1) and interclass correlation coefficients (ICC 2.1). [Results] The test-retest reliability ICC 1.1 and ICC 2.1 were all high. The ICC 1.1 was >0.90. The ICC 2.1 was 0.93. [Conclusion] We developed the trunk righting test as a novel objective evaluation method for trunk function. As the study included inexperienced therapists, the results suggest that the trunk righting test could be used in the clinic, independent of the experience of the therapists. PMID:26157279

  15. Unsteady aerodynamics modeling for flight dynamics application

    NASA Astrophysics Data System (ADS)

    Wang, Qing; He, Kai-Feng; Qian, Wei-Qi; Zhang, Tian-Jiao; Cheng, Yan-Qing; Wu, Kai-Yuan

    2012-02-01

    In view of engineering application, it is practicable to decompose the aerodynamics into three components: the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due to unsteady separated and vortical flow. The first and the second components can be presented in conventional forms, while the third is described using a one-order differential equation and a radial-basis-function (RBF) network. For an aircraft configuration, the mathematical models of 6-component aerodynamic coefficients are set up from the wind tunnel test data of pitch, yaw, roll, and coupled yawroll large-amplitude oscillations. The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynamics, respectively. The results show that: (1) unsteady aerodynamics has no effect upon the existence of trim points, but affects their stability; (2) unsteady aerodynamics has great effects upon the existence, stability, and amplitudes of periodic solutions; and (3) unsteady aerodynamics changes the stable regions of trim points obviously. Furthermore, the dynamic responses of the aircraft to elevator deflections are inspected. It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft. Finally, the effects of unsteady aerodynamics on the post-stall maneuverability are analyzed by numerical simulation.

  16. Aerodynamics of bird flight

    NASA Astrophysics Data System (ADS)

    Dvořák, Rudolf

    2016-03-01

    Unlike airplanes birds must have either flapping or oscillating wings (the hummingbird). Only such wings can produce both lift and thrust - two sine qua non attributes of flying.The bird wings have several possibilities how to obtain the same functions as airplane wings. All are realized by the system of flight feathers. Birds have also the capabilities of adjusting the shape of the wing according to what the immediate flight situation demands, as well as of responding almost immediately to conditions the flow environment dictates, such as wind gusts, object avoidance, target tracking, etc. In bird aerodynamics also the tail plays an important role. To fly, wings impart downward momentum to the surrounding air and obtain lift by reaction. How this is achieved under various flight situations (cruise flight, hovering, landing, etc.), and what the role is of the wing-generated vortices in producing lift and thrust is discussed.The issue of studying bird flight experimentally from in vivo or in vitro experiments is also briefly discussed.

  17. Models for predicting objective function weights in prostate cancer IMRT

    SciTech Connect

    Boutilier, Justin J. Lee, Taewoo; Craig, Tim; Sharpe, Michael B.; Chan, Timothy C. Y.

    2015-04-15

    Purpose: To develop and evaluate the clinical applicability of advanced machine learning models that simultaneously predict multiple optimization objective function weights from patient geometry for intensity-modulated radiation therapy of prostate cancer. Methods: A previously developed inverse optimization method was applied retrospectively to determine optimal objective function weights for 315 treated patients. The authors used an overlap volume ratio (OV) of bladder and rectum for different PTV expansions and overlap volume histogram slopes (OVSR and OVSB for the rectum and bladder, respectively) as explanatory variables that quantify patient geometry. Using the optimal weights as ground truth, the authors trained and applied three prediction models: logistic regression (LR), multinomial logistic regression (MLR), and weighted K-nearest neighbor (KNN). The population average of the optimal objective function weights was also calculated. Results: The OV at 0.4 cm and OVSR at 0.1 cm features were found to be the most predictive of the weights. The authors observed comparable performance (i.e., no statistically significant difference) between LR, MLR, and KNN methodologies, with LR appearing to perform the best. All three machine learning models outperformed the population average by a statistically significant amount over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and dose to the bladder, rectum, CTV, and PTV. When comparing the weights directly, the LR model predicted bladder and rectum weights that had, on average, a 73% and 74% relative improvement over the population average weights, respectively. The treatment plans resulting from the LR weights had, on average, a rectum V70Gy that was 35% closer to the clinical plan and a bladder V70Gy that was 29% closer, compared to the population average weights. Similar results were observed for all other clinical metrics. Conclusions: The authors demonstrated that the KNN and MLR

  18. Probabilistic objective functions for margin-less IMRT planning

    NASA Astrophysics Data System (ADS)

    Bohoslavsky, Román; Witte, Marnix G.; Janssen, Tomas M.; van Herk, Marcel

    2013-06-01

    We present a method to implement probabilistic treatment planning of intensity-modulated radiation therapy using custom software plugins in a commercial treatment planning system. Our method avoids the definition of safety-margins by directly including the effect of geometrical uncertainties during optimization when objective functions are evaluated. Because the shape of the resulting dose distribution implicitly defines the robustness of the plan, the optimizer has much more flexibility than with a margin-based approach. We expect that this added flexibility helps to automatically strike a better balance between target coverage and dose reduction for surrounding healthy tissue, especially for cases where the planning target volume overlaps organs at risk. Prostate cancer treatment planning was chosen to develop our method, including a novel technique to include rotational uncertainties. Based on population statistics, translations and rotations are simulated independently following a marker-based IGRT correction strategy. The effects of random and systematic errors are incorporated by first blurring and then shifting the dose distribution with respect to the clinical target volume. For simplicity and efficiency, dose-shift invariance and a rigid-body approximation are assumed. Three prostate cases were replanned using our probabilistic objective functions. To compare clinical and probabilistic plans, an evaluation tool was used that explicitly incorporates geometric uncertainties using Monte-Carlo methods. The new plans achieved similar or better dose distributions than the original clinical plans in terms of expected target coverage and rectum wall sparing. Plan optimization times were only about a factor of two higher than in the original clinical system. In conclusion, we have developed a practical planning tool that enables margin-less probability-based treatment planning with acceptable planning times, achieving the first system that is feasible for clinical

  19. Gamma-ray luminosity function of BL Lac objects

    NASA Astrophysics Data System (ADS)

    Zeng, Houdun; Yan, Dahai; Zhang, Li

    2014-06-01

    The gamma-ray luminosity function (GLF) of BL Lac objects is constructed by using a sample of BL Lac objects with redshifts selected from the Second LAT AGN catalog. The GLFs of BL Lacs in the frame of the pure density evolution (PDE), the pure luminosity evolution (PLE), and the luminosity-dependent density (LDDE) models are determined by using the Markov Chain Monte Carlo (MCMC) technique, respectively. Our results suggest that the PDE model can give best description for BL Lac GLF based on the combination of constraints of model parameters and good fits to the observed data of Fermi-Large Area Telescope (LAT) BL Lacs, but other two models (PLE and LDDE) cannot be excluded. Based on our constructed GLFs, the contribution to the extragalactic diffuse gamma-ray background (EGRB) from BL Lacs is estimated, and ˜1-5 per cent of the EGRB in the 0.1-100 GeV band is found to come from unresolved BL Lacs (including the cascade emission). In addition, it is found that the BL Lac GLF is very different from flat spectrum radio quasar GLF and then the contribution of blazars to the EGRB should be estimated separately.

  20. PREFACE: Aerodynamic sound Aerodynamic sound

    NASA Astrophysics Data System (ADS)

    Akishita, Sadao

    2010-02-01

    The modern theory of aerodynamic sound originates from Lighthill's two papers in 1952 and 1954, as is well known. I have heard that Lighthill was motivated in writing the papers by the jet-noise emitted by the newly commercialized jet-engined airplanes at that time. The technology of aerodynamic sound is destined for environmental problems. Therefore the theory should always be applied to newly emerged public nuisances. This issue of Fluid Dynamics Research (FDR) reflects problems of environmental sound in present Japanese technology. The Japanese community studying aerodynamic sound has held an annual symposium since 29 years ago when the late Professor S Kotake and Professor S Kaji of Teikyo University organized the symposium. Most of the Japanese authors in this issue are members of the annual symposium. I should note the contribution of the two professors cited above in establishing the Japanese community of aerodynamic sound research. It is my pleasure to present the publication in this issue of ten papers discussed at the annual symposium. I would like to express many thanks to the Editorial Board of FDR for giving us the chance to contribute these papers. We have a review paper by T Suzuki on the study of jet noise, which continues to be important nowadays, and is expected to reform the theoretical model of generating mechanisms. Professor M S Howe and R S McGowan contribute an analytical paper, a valuable study in today's fluid dynamics research. They apply hydrodynamics to solve the compressible flow generated in the vocal cords of the human body. Experimental study continues to be the main methodology in aerodynamic sound, and it is expected to explore new horizons. H Fujita's study on the Aeolian tone provides a new viewpoint on major, longstanding sound problems. The paper by M Nishimura and T Goto on textile fabrics describes new technology for the effective reduction of bluff-body noise. The paper by T Sueki et al also reports new technology for the

  1. FUNCTION FOLLOWS FORM: ACTIVATION OF SHAPE & FUNCTION FEATURES DURING OBJECT IDENTIFICATION

    PubMed Central

    Yee, Eiling; Huffstetler, Stacy; Thompson-Schill, Sharon L.

    2011-01-01

    Most theories of semantic memory characterize knowledge of a given object as comprising a set of semantic features. But how does conceptual activation of these features proceed during object identification? We present the results of a pair of experiments that demonstrate that object recognition is a dynamically unfolding process in which function follows form. We used eye movements to explore whether activating one object’s concept leads to the activation of others that share perceptual (shape) or abstract (function) features. Participants viewed four-picture displays and clicked on the picture corresponding to a heard word. In critical trials, the conceptual representation of one of the objects in the display was similar in shape or function (i.e., its purpose) to the heard word. Importantly, this similarity was not apparent in the visual depictions (e.g., for the target “frisbee,” the shape-related object was a triangular slice of pizza – a shape that a frisbee cannot take); preferential fixations on the related object were therefore attributable to overlap of the conceptual representations on the relevant features. We observed relatedness effects for both shape and function, but shape effects occurred earlier than function effects. We discuss the implications of these findings for current accounts of the representation of semantic memory. PMID:21417543

  2. Objective Measures in Aesthetic and Functional Nasal Surgery – Perspectives on Nasal Form and Function

    PubMed Central

    Pawar, Sachin S.; Garcia, Guilherme J.M.; Kimbell, Julia S.; Rhee, John S.

    2011-01-01

    The outcomes of aesthetic and functional nasal surgery are difficult to assess objectively due to the intricate balance between nasal form and function. Despite historical emphasis on patient-reported subjective measures, objective measures are gaining importance in both research and the current outcomes-driven healthcare environment. Objective measures presently available have several shortcomings which limit their routine clinical use. In particular, the low correlation between objective and subjective measures poses a major challenge. However, advances in computer, imaging, and bioengineering technology are now setting the stage for the development of innovative objective assessment tools for nasal surgery that can potentially address some of the current limitations. Assessment of nasal form following aesthetic surgery is evolving from two-dimensional analysis to more sophisticated three-dimensional analysis. Similarly, assessment of nasal function is evolving with the introduction of computational fluid dynamics techniques, which allow for a detailed description of the biophysics of nasal airflow. In this paper, we present an overview of objective measures in both aesthetic and functional nasal surgery and discuss future trends and applications that have the potential to change the way we assess nasal form and function. PMID:20665410

  3. Nash equilibrium and multi criterion aerodynamic optimization

    NASA Astrophysics Data System (ADS)

    Tang, Zhili; Zhang, Lianhe

    2016-06-01

    Game theory and its particular Nash Equilibrium (NE) are gaining importance in solving Multi Criterion Optimization (MCO) in engineering problems over the past decade. The solution of a MCO problem can be viewed as a NE under the concept of competitive games. This paper surveyed/proposed four efficient algorithms for calculating a NE of a MCO problem. Existence and equivalence of the solution are analyzed and proved in the paper based on fixed point theorem. Specific virtual symmetric Nash game is also presented to set up an optimization strategy for single objective optimization problems. Two numerical examples are presented to verify proposed algorithms. One is mathematical functions' optimization to illustrate detailed numerical procedures of algorithms, the other is aerodynamic drag reduction of civil transport wing fuselage configuration by using virtual game. The successful application validates efficiency of algorithms in solving complex aerodynamic optimization problem.

  4. HYSHOT-2 Aerodynamics

    NASA Astrophysics Data System (ADS)

    Cain, T.; Owen, R.; Walton, C.

    2005-02-01

    The scramjet flight test Hyshot-2, flew on the 30 July 2002. The programme, led by the University of Queensland, had the primary objective of obtaining supersonic combustion data in flight for comparison with measurements made in shock tunnels. QinetiQ was one of the sponsors, and also provided aerodynamic data and trajectory predictions for the ballistic re-entry of the spinning sounding rocket. The unconventional missile geometry created by the nose-mounted asymmetric-scramjet in conjunction with the high angle of attack during re-entry makes the problem interesting. This paper presents the wind tunnel measurements and aerodynamic calculations used as input for the trajectory prediction. Indirect comparison is made with data obtained in the Hyshot-2 flight using a 6 degree-of-freedom trajectory simulation.

  5. Probe and object function reconstruction in incoherent stem imaging

    SciTech Connect

    Nellist, P.D.; Pennycook, S.J.

    1996-09-01

    Using the phase-object approximation it is shown how an annular dark- field (ADF) detector in a scanning transmission electron microscope (STEM) leads to an image which can be described by an incoherent model. The point spread function is found to be simply the illuminating probe intensity. An important consequence of this is that there is no phase problem in the imaging process, which allows various image processing methods to be applied directly to the image intensity data. Using an image of a GaAs<110>, the probe intensity profile is reconstructed, confirming the existence of a 1.3 {Angstrom} probe in a 300kV STEM. It is shown that simply deconvolving this reconstructed probe from the image data does not improve its interpretability because the dominant effects of the imaging process arise simply from the restricted resolution of the microscope. However, use of the reconstructed probe in a maximum entropy reconstruction is demonstrated, which allows information beyond the resolution limit to be restored and does allow improved image interpretation.

  6. Expertise Increases the Functional Overlap between Face and Object Perception

    ERIC Educational Resources Information Center

    McKeeff, Thomas J.; McGugin, Rankin W.; Tong, Frank; Gauthier, Isabel

    2010-01-01

    Recent studies indicate that expertise with objects can interfere with face processing. Although competition occurs between faces and objects of expertise, it remains unclear whether this reflects an expertise-specific bottleneck or the fact that objects of expertise grab attention and thereby consume more central resources. We investigated the…

  7. Reducing uncertainty about objective functions in adaptive management

    USGS Publications Warehouse

    Williams, B.K.

    2012-01-01

    This paper extends the uncertainty framework of adaptive management to include uncertainty about the objectives to be used in guiding decisions. Adaptive decision making typically assumes explicit and agreed-upon objectives for management, but allows for uncertainty as to the structure of the decision process that generates change through time. Yet it is not unusual for there to be uncertainty (or disagreement) about objectives, with different stakeholders expressing different views not only about resource responses to management but also about the appropriate management objectives. In this paper I extend the treatment of uncertainty in adaptive management, and describe a stochastic structure for the joint occurrence of uncertainty about objectives as well as models, and show how adaptive decision making and the assessment of post-decision monitoring data can be used to reduce uncertainties of both kinds. Different degrees of association between model and objective uncertainty lead to different patterns of learning about objectives. ?? 2011.

  8. Embedding objects during 3D printing to add new functionalities.

    PubMed

    Yuen, Po Ki

    2016-07-01

    A novel method for integrating and embedding objects to add new functionalities during 3D printing based on fused deposition modeling (FDM) (also known as fused filament fabrication or molten polymer deposition) is presented. Unlike typical 3D printing, FDM-based 3D printing could allow objects to be integrated and embedded during 3D printing and the FDM-based 3D printed devices do not typically require any post-processing and finishing. Thus, various fluidic devices with integrated glass cover slips or polystyrene films with and without an embedded porous membrane, and optical devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber were 3D printed to demonstrate the versatility of the FDM-based 3D printing and embedding method. Fluid perfusion flow experiments with a blue colored food dye solution were used to visually confirm fluid flow and/or fluid perfusion through the embedded porous membrane in the 3D printed fluidic devices. Similar to typical 3D printed devices, FDM-based 3D printed devices are translucent at best unless post-polishing is performed and optical transparency is highly desirable in any fluidic devices; integrated glass cover slips or polystyrene films would provide a perfect optical transparent window for observation and visualization. In addition, they also provide a compatible flat smooth surface for biological or biomolecular applications. The 3D printed fluidic devices with an embedded porous membrane are applicable to biological or chemical applications such as continuous perfusion cell culture or biocatalytic synthesis but without the need for any post-device assembly and finishing. The 3D printed devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber would have applications in display, illumination, or optical applications. Furthermore, the FDM-based 3D printing and embedding method could also be utilized to print casting molds with an integrated glass bottom for polydimethylsiloxane (PDMS) device replication

  9. An Eavesdropping Game with SINR as an Objective Function

    NASA Astrophysics Data System (ADS)

    Garnaev, Andrey; Trappe, Wade

    We examine eavesdropping over wireless channels, where secret communication in the presence of an eavesdropper is formulated as a zero-sum game. In our problem, the legitimate receiver does not have complete knowledge about the environment, i.e. does not know the exact values of the channels gains, but instead knows just their distribution. To communicate secretly, the user must decide how to transmit its information across subchannels under a worst-case condition and thus, the legal user faces a max-min optimization problem. To formulate the optimization problem, we pose the environment as a secondary player in a zero-sum game whose objective is to hamper communication by the user. Thus, nature faces a min-max optimization problem. In our formulation, we consider signal-to-interference ratio (SINR) as a payoff function. We then study two specific scenarios: (i) the user does not know the channels gains; and (ii) the user does not know how the noise is distributed among the main channels. We show that in model (i) in his optimal behavior the user transmits signal energy uniformly across a subset of selected channels. In model (ii), if the user does not know the eavesdropper’s channel gains he/she also employs a strategy involving uniformly distributing energy across a subset of channels. However, if the user acquires extra knowledge about environment, e.g. the eavesdropper’s channel gains, the user may better tune his/her power allocation among the channels. We provide criteria for selecting which channels the user should transmit on by deriving closed-form expressions for optimal strategies for both players.

  10. How You Use It Matters: Object Function Guides Attention During Visual Search in Scenes.

    PubMed

    Castelhano, Monica S; Witherspoon, Richelle L

    2016-05-01

    How does one know where to look for objects in scenes? Objects are seen in context daily, but also used for specific purposes. Here, we examined whether an object's function can guide attention during visual search in scenes. In Experiment 1, participants studied either the function (function group) or features (feature group) of a set of invented objects. In a subsequent search, the function group located studied objects faster than novel (unstudied) objects, whereas the feature group did not. In Experiment 2, invented objects were positioned in locations that were either congruent or incongruent with the objects' functions. Search for studied objects was faster for function-congruent locations and hampered for function-incongruent locations, relative to search for novel objects. These findings demonstrate that knowledge of object function can guide attention in scenes, and they have important implications for theories of visual cognition, cognitive neuroscience, and developmental and ecological psychology. PMID:27022016

  11. Functional dissociation between action and perception of object shape in developmental visual object agnosia.

    PubMed

    Freud, Erez; Ganel, Tzvi; Avidan, Galia; Gilaie-Dotan, Sharon

    2016-03-01

    According to the two visual systems model, the cortical visual system is segregated into a ventral pathway mediating object recognition, and a dorsal pathway mediating visuomotor control. In the present study we examined whether the visual control of action could develop normally even when visual perceptual abilities are compromised from early childhood onward. Using his fingers, LG, an individual with a rare developmental visual object agnosia, manually estimated (perceptual condition) the width of blocks that varied in width and length (but not in overall size), or simply picked them up across their width (grasping condition). LG's perceptual sensitivity to target width was profoundly impaired in the manual estimation task compared to matched controls. In contrast, the sensitivity to object shape during grasping, as measured by maximum grip aperture (MGA), the time to reach the MGA, the reaction time and the total movement time were all normal in LG. Further analysis, however, revealed that LG's sensitivity to object shape during grasping emerged at a later time stage during the movement compared to controls. Taken together, these results demonstrate a dissociation between action and perception of object shape, and also point to a distinction between different stages of the grasping movement, namely planning versus online control. Moreover, the present study implies that visuomotor abilities can develop normally even when perceptual abilities developed in a profoundly impaired fashion. PMID:26827163

  12. Obtaining Functional Results: Relating Needs Assessment, Needs Analysis, and Objectives.

    ERIC Educational Resources Information Center

    Kaufman, Roger

    1986-01-01

    An algorithm or decision chart is presented which provides basic decision steps to help management decide what data should be collected to derive valid and correct objectives, and to determine what levels of objectives will be selected relative to products, outputs, or outcomes of an organization. (MBR)

  13. Distinctions between manipulation and function knowledge of objects: evidence from functional magnetic resonance imaging.

    PubMed

    Boronat, Consuelo B; Buxbaum, Laurel J; Coslett, H Branch; Tang, Kathy; Saffran, Eleanor M; Kimberg, Daniel Y; Detre, John A

    2005-05-01

    A prominent account of conceptual knowledge proposes that information is distributed over visual, tactile, auditory, motor and verbal-declarative attribute domains to the degree to which these features were activated when the knowledge was acquired [D.A. Allport, Distributed memory, modular subsystems and dysphagia, In: S.K. Newman, R. Epstein (Eds.), Current perspectives in dysphagia, Churchill Livingstone, Edinburgh, 1985, pp. 32-60]. A corollary is that when drawing upon this knowledge (e.g., to answer questions), particular aspects of this distributed information is re-activated as a function of the requirements of the task at hand [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects. Brain and Language, 82 (2002) 179-199; L.J. Buxbaum, T. Veramonti, M.F. Schwartz, Function and manipulation tool knowledge in apraxia: knowing 'what for' but not 'how', Neurocase, 6 (2000) 83-97; W. Simmons, L. Barsalou, The similarity-in-topography principle: Reconciling theories of conceptual deficits, Cognitive Neuropsychology, 20 (2003) 451-486]. This account predicts that answering questions about object manipulation should activate brain regions previously identified as components of the distributed sensory-motor system involved in object use, whereas answering questions about object function (that is, the purpose that it serves) should activate regions identified as components of the systems supporting verbal-declarative features. These predictions were tested in a functional magnetic resonance imaging (fMRI) study in which 15 participants viewed picture or word pairs denoting manipulable objects and determined whether the objects are manipulated similarly (M condition) or serve the same function (F condition). Significantly greater and more extensive activations in the left inferior parietal lobe bordering the intraparietal sulcus were seen in the M condition with pictures and, to a lesser

  14. Configuration Aerodynamics: Past - Present - Future

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Agrawal, Shreekant; Bencze, Daniel P.; Kulfan, Robert M.; Wilson, Douglas L.

    1999-01-01

    The Configuration Aerodynamics (CA) element of the High Speed Research (HSR) program is managed by a joint NASA and Industry team, referred to as the Technology Integration Development (ITD) team. This team is responsible for the development of a broad range of technologies for improved aerodynamic performance and stability and control characteristics at subsonic to supersonic flight conditions. These objectives are pursued through the aggressive use of advanced experimental test techniques and state of the art computational methods. As the HSR program matures and transitions into the next phase the objectives of the Configuration Aerodynamics ITD are being refined to address the drag reduction needs and stability and control requirements of High Speed Civil Transport (HSCT) aircraft. In addition, the experimental and computational tools are being refined and improved to meet these challenges. The presentation will review the work performed within the Configuration Aerodynamics element in 1994 and 1995 and then discuss the plans for the 1996-1998 time period. The final portion of the presentation will review several observations of the HSR program and the design activity within Configuration Aerodynamics.

  15. Sound symbolic naming of novel objects is a graded function.

    PubMed

    Thompson, Patrick D; Estes, Zachary

    2011-12-01

    Although linguistic traditions of the last century assumed that there is no link between sound and meaning (i.e., arbitrariness), recent research has established a nonarbitrary relation between sound and meaning (i.e., sound symbolism). For example, some sounds (e.g., /u/ as in took) suggest bigness whereas others (e.g., /i/ as in tiny) suggest smallness. We tested whether sound symbolism only marks contrasts (e.g., small versus big things) or whether it marks object properties in a graded manner (e.g., small, medium, and large things). In two experiments, participants viewed novel objects (i.e., greebles) of varying size and chose the most appropriate name for each object from a list of visually or auditorily presented nonwords that varied incrementally in the number of "large" and "small" phonemes. For instance, "wodolo" contains all large-sounding phonemes, whereas "kitete" contains all small-sounding phonemes. Participants' choices revealed a graded relationship between sound and size: The size of the object linearly predicted the number of large-sounding phonemes in its preferred name. That is, small, medium, and large objects elicited names with increasing numbers of large-sounding phonemes. The results are discussed in relation to cross-modal processing, gesture, and vocal pitch. PMID:21895561

  16. Aerodynamics via acoustics - Application of acoustic formulas for aerodynamic calculations

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.

    1986-01-01

    Prediction of aerodynamic loads on bodies in arbitrary motion is considered from an acoustic point of view, i.e., in a frame of reference fixed in the undisturbed medium. An inhomogeneous wave equation which governs the disturbance pressure is constructed and solved formally using generalized function theory. When the observer is located on the moving body surface there results a singular linear integral equation for surface pressure. Two different methods for obtaining such equations are discussed. Both steady and unsteady aerodynamic calculations are considered. Two examples are presented, the more important being an application to propeller aerodynamics. Of particular interest for numerical applications is the analytical behavior of the kernel functions in the various integral equations.

  17. Aerodynamics Via Acoustics: Application of Acoustic Formulas for Aerodynamic Calculations

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.

    1986-01-01

    Prediction of aerodynamic loads on bodies in arbitrary motion is considered from an acoustic point of view, i.e., in a frame of reference fixed in the undisturbed medium. An inhomogeneous wave equation which governs the disturbance pressure is constructed and solved formally using generalized function theory. When the observer is located on the moving body surface there results a singular linear integral equation for surface pressure. Two different methods for obtaining such equations are discussed. Both steady and unsteady aerodynamic calculations are considered. Two examples are presented, the more important being an application to propeller aerodynamics. Of particular interest for numerical applications is the analytical behavior of the kernel functions in the various integral equations.

  18. Numerical Aerodynamic Simulation (NAS)

    NASA Technical Reports Server (NTRS)

    Peterson, V. L.; Ballhaus, W. F., Jr.; Bailey, F. R.

    1983-01-01

    The history of the Numerical Aerodynamic Simulation Program, which is designed to provide a leading-edge capability to computational aerodynamicists, is traced back to its origin in 1975. Factors motivating its development and examples of solutions to successively refined forms of the governing equations are presented. The NAS Processing System Network and each of its eight subsystems are described in terms of function and initial performance goals. A proposed usage allocation policy is discussed and some initial problems being readied for solution on the NAS system are identified.

  19. s2: Object oriented wrapper for functions on the sphere

    NASA Astrophysics Data System (ADS)

    McEwen, Jason C.

    2016-06-01

    The s2 package can represent any arbitrary function defined on the sphere. Both real space map and harmonic space spherical harmonic representations are supported. Basic sky representations have been extended to simulate full sky noise distributions and Gaussian cosmic microwave background realisations. Support for the representation and convolution of beams is also provided. The code requires HEALPix (ascl:1107.018) and CFITSIO (ascl:1010.001).

  20. Classical Aerodynamic Theory

    NASA Technical Reports Server (NTRS)

    Jones, R. T. (Compiler)

    1979-01-01

    A collection of papers on modern theoretical aerodynamics is presented. Included are theories of incompressible potential flow and research on the aerodynamic forces on wing and wing sections of aircraft and on airship hulls.

  1. Monotone Approximations of Minimum and Maximum Functions and Multi-objective Problems

    SciTech Connect

    Stipanovic, Dusan M.; Tomlin, Claire J.; Leitmann, George

    2012-12-15

    In this paper the problem of accomplishing multiple objectives by a number of agents represented as dynamic systems is considered. Each agent is assumed to have a goal which is to accomplish one or more objectives where each objective is mathematically formulated using an appropriate objective function. Sufficient conditions for accomplishing objectives are derived using particular convergent approximations of minimum and maximum functions depending on the formulation of the goals and objectives. These approximations are differentiable functions and they monotonically converge to the corresponding minimum or maximum function. Finally, an illustrative pursuit-evasion game example with two evaders and two pursuers is provided.

  2. Quantitative objective assessment of peripheral nociceptive C fibre function.

    PubMed Central

    Parkhouse, N; Le Quesne, P M

    1988-01-01

    A technique is described for the quantitative assessment of peripheral nociceptive C fibre function by measurement of the axon reflex flare. Acetylcholine, introduced by electrophoresis, is used to stimulate a ring of nociceptive C fibre endings at the centre of which the increase in blood flow is measured with a laser Doppler flowmeter. This flare (neurogenic vasodilatation) has been compared with mechanically or chemically stimulated non-neurogenic cutaneous vasodilation. The flare is abolished by local anaesthetic and is absent in denervated skin. The flare has been measured on the sole of the foot of 96 healthy subjects; its size decreases with age in males, but not in females. Images PMID:3351528

  3. NASA aerodynamics program

    NASA Technical Reports Server (NTRS)

    Williams, Louis J.; Hessenius, Kristin A.; Corsiglia, Victor R.; Hicks, Gary; Richardson, Pamela F.; Unger, George; Neumann, Benjamin; Moss, Jim

    1992-01-01

    The annual accomplishments is reviewed for the Aerodynamics Division during FY 1991. The program includes both fundamental and applied research directed at the full spectrum of aerospace vehicles, from rotorcraft to planetary entry probes. A comprehensive review is presented of the following aerodynamics elements: computational methods and applications; CFD validation; transition and turbulence physics; numerical aerodynamic simulation; test techniques and instrumentation; configuration aerodynamics; aeroacoustics; aerothermodynamics; hypersonics; subsonics; fighter/attack aircraft and rotorcraft.

  4. NASA aerodynamics program

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.; Schairer, Edward; Hicks, Gary; Wander, Stephen; Blankson, Isiaiah; Rose, Raymond; Olson, Lawrence; Unger, George

    1990-01-01

    Presented here is a comprehensive review of the following aerodynamics elements: computational methods and applications, computational fluid dynamics (CFD) validation, transition and turbulence physics, numerical aerodynamic simulation, drag reduction, test techniques and instrumentation, configuration aerodynamics, aeroacoustics, aerothermodynamics, hypersonics, subsonic transport/commuter aviation, fighter/attack aircraft and rotorcraft.

  5. 1997 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1999-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Aerodynamic Performance Workshop on February 25-28, 1997. The workshop was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, Flight Controls, Supersonic Laminar Flow Control, and Sonic Boom Prediction. The workshop objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientist and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT Motion Simulator results were presented along with executive summaries for all the Aerodynamic Performance technology areas.

  6. 1999 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    Hahne, David E. (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1999 Aerodynamic Performance Technical Review on February 8-12, 1999 in Anaheim, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in the areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High Lift, and Flight Controls. The review objectives were to: (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working on HSCT aerodynamics. In particular, single and midpoint optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented, along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program. This Volume 1/Part 1 publication covers configuration aerodynamics.

  7. Conceptual Tools: Functional System, List of Functions, Operational Definitions of Functions. Method for Determining Language Objectives and Criteria, Volume III.

    ERIC Educational Resources Information Center

    Setzler, Hubert H., Jr.; And Others

    The conceptual tools used in the communication/language objectives-based system (C/LOBS), which supports the front-end analysis efforts of the Defense Language Institute Foreign Language Center, are examined. The C/LOBS project, which is described in 13 volumes and an executive summary, functions as a subsystem of the instructional systems…

  8. Aerodynamic design on high-speed trains

    NASA Astrophysics Data System (ADS)

    Ding, San-San; Li, Qiang; Tian, Ai-Qin; Du, Jian; Liu, Jia-Li

    2016-01-01

    Compared with the traditional train, the operational speed of the high-speed train has largely improved, and the dynamic environment of the train has changed from one of mechanical domination to one of aerodynamic domination. The aerodynamic problem has become the key technological challenge of high-speed trains and significantly affects the economy, environment, safety, and comfort. In this paper, the relationships among the aerodynamic design principle, aerodynamic performance indexes, and design variables are first studied, and the research methods of train aerodynamics are proposed, including numerical simulation, a reduced-scale test, and a full-scale test. Technological schemes of train aerodynamics involve the optimization design of the streamlined head and the smooth design of the body surface. Optimization design of the streamlined head includes conception design, project design, numerical simulation, and a reduced-scale test. Smooth design of the body surface is mainly used for the key parts, such as electric-current collecting system, wheel truck compartment, and windshield. The aerodynamic design method established in this paper has been successfully applied to various high-speed trains (CRH380A, CRH380AM, CRH6, CRH2G, and the Standard electric multiple unit (EMU)) that have met expected design objectives. The research results can provide an effective guideline for the aerodynamic design of high-speed trains.

  9. Aerodynamic design on high-speed trains

    NASA Astrophysics Data System (ADS)

    Ding, San-San; Li, Qiang; Tian, Ai-Qin; Du, Jian; Liu, Jia-Li

    2016-04-01

    Compared with the traditional train, the operational speed of the high-speed train has largely improved, and the dynamic environment of the train has changed from one of mechanical domination to one of aerodynamic domination. The aerodynamic problem has become the key technological challenge of high-speed trains and significantly affects the economy, environment, safety, and comfort. In this paper, the relationships among the aerodynamic design principle, aerodynamic performance indexes, and design variables are first studied, and the research methods of train aerodynamics are proposed, including numerical simulation, a reduced-scale test, and a full-scale test. Technological schemes of train aerodynamics involve the optimization design of the streamlined head and the smooth design of the body surface. Optimization design of the streamlined head includes conception design, project design, numerical simulation, and a reduced-scale test. Smooth design of the body surface is mainly used for the key parts, such as electric-current collecting system, wheel truck compartment, and windshield. The aerodynamic design method established in this paper has been successfully applied to various high-speed trains (CRH380A, CRH380AM, CRH6, CRH2G, and the Standard electric multiple unit (EMU)) that have met expected design objectives. The research results can provide an effective guideline for the aerodynamic design of high-speed trains.

  10. An Adaptive Objective Function for Evaporation Duct Estimations from Radar Sea Echo

    NASA Astrophysics Data System (ADS)

    Zhang, Jin-Peng; Wu, Zhen-Sen; Wang, Bo

    2011-03-01

    In the process of atmospheric refractivity estimation from radar sea echo, the objective function that calculates the match between the predicted and observed field plays an important role. To reduce the effect of noises from long ranges on the objective function, we present a selection method of final ranges for inversion. An adaptive objective function is introduced with a linear distance weight added to the least squares error function (LSEF). Through an evaporation duct height (EDH) retrieving process, the performance of the adaptive objective function is evaluated. The result illustrates that the present method performs better than the LSEF in EDH inversions from clutters with different clutter-to-noise ratios.

  11. User's manual for an aerodynamic optimization scheeme that updates flow variables and design parameters simultaneously

    NASA Technical Reports Server (NTRS)

    Rizk, Magdi H.

    1988-01-01

    This user's manual is presented for an aerodynamic optimization program that updates flow variables and design parameters simultaneously. The program was developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The program was tested by applying it to the problem of optimizing propeller designs. Some reference to this particular application is therefore made in the manual. However, the optimization scheme is suitable for application to general aerodynamic design problems. A description of the approach used in the optimization scheme is first presented, followed by a description of the use of the program.

  12. Aerodynamic Loads Induced by a Rotor on a Body of Revolution

    NASA Technical Reports Server (NTRS)

    Smith, Charles A.; Betzina, Mark D.

    1986-01-01

    A wind-tunnel investigation was conducted in which aerodynamic loads were measured on a small-scale helicopter rotor and a body of revolution located close to it as an idealized model of a fuselage. The objective was to study the aerodynamic interactions as a function of forward speed, rotor thrust, and rotor/body position. Results show that body loads, normalized by rotor thrust, are functions of the ratio between free-stream velocity and the hover-induced velocity predicted by momentum theory.

  13. Evaluation and modeling of aerodynamic properties of mung bean seeds

    NASA Astrophysics Data System (ADS)

    Shahbazi, Feizollah

    2015-01-01

    Aerodynamic properties of solid materials have long been used to convey and separate seeds and grains during post harvest operations. The objective of this study was the evaluation of the aerodynamic properties of mung bean seeds as a function of moisture content and two grades referred to above and below a cut point of 4.8 mm in length. The results showed that as the moisture content increased from 7.8 to 25% (w.b.), the terminal velocity of seeds increased following a polynomial relationship, from 7.28 to 8.79 and 6.02 to 7.12 m s-1, for grades A and B, respectively. Seeds at grade A had terminal velocities with a mean value of 8.05 m s-1, while at grade B had a mean value of 6.46 m s-1. The Reynolds number of both grades increased linearly with the increase of seeds moisture content, while the drag coefficient decreased with the increase of moisture content. Mathematical relationships were developed to relate the change in seeds moisture content with the obtained values of aerodynamic properties. The analysis of variance showed that moisture content had a significant effect, at 1% probability level, on all the aerodynamics properties of mung beans.

  14. Active Control of Aerodynamic Noise Sources

    NASA Technical Reports Server (NTRS)

    Reynolds, Gregory A.

    2001-01-01

    Aerodynamic noise sources become important when propulsion noise is relatively low, as during aircraft landing. Under these conditions, aerodynamic noise from high-lift systems can be significant. The research program and accomplishments described here are directed toward reduction of this aerodynamic noise. Progress toward this objective include correction of flow quality in the Low Turbulence Water Channel flow facility, development of a test model and traversing mechanism, and improvement of the data acquisition and flow visualization capabilities in the Aero. & Fluid Dynamics Laboratory. These developments are described in this report.

  15. Design Exploration of Aerodynamic Wing Shape for RLV Flyback Booster

    NASA Astrophysics Data System (ADS)

    Chiba, Kazuhisa; Obayashi, Shigeru; Nakahashi, Kazuhiro

    The wing shape of flyback booster for a Two-Stage-To-Orbit reusable launch vehicle has been optimized considering four objectives. The objectives are to minimize the shift of aerodynamic center between supersonic and transonic conditions, transonic pitching moment and transonic drag coefficient, as well as to maximize subsonic lift coefficient. The three-dimensional Reynolds-averaged Navier-Stokes computation using the modified Spalart-Allmaras one-equation model is used in aerodynamic evaluation accounting for possible flow separations. Adaptive range multi-objective genetic algorithm is used for the present study because tradeoff can be obtained using a smaller number of individuals than conventional multi-objective genetic algorithms. Consequently, four-objective optimization has produced 102 non-dominated solutions, which represent tradeoff information among four objective functions. Moreover, Self-Organizing Maps have been used to analyze the present non-dominated solutions and to visualize tradeoffs and influence of design variables to the four objectives. Self-Organizing Maps contoured by the four objective functions and design variables are found to visualize tradeoffs and effects of each design variable.

  16. 1998 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    McMillin, S. Naomi (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1998 Aerodynamic Performance Technical Review on February 9-13, in Los Angeles, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working HSCT aerodynamics. In particular, single and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program.

  17. 1999 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    Hahne, David E. (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1999 Aerodynamic Performance Technical Review on February 8-12, 1999 in Anaheim, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in the areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working on HSCT aerodynamics. In particular, single and midpoint optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented, along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program. This Volume 1/Part 2 publication covers the design optimization and testing sessions.

  18. 1998 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    McMillin, S. Naomi (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1998 Aerodynamic Performance Technical Review on February 9-13, in Los Angeles, California. The review was designed to bring together NASA and industry HighSpeed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of. Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, and Flight Controls. The review objectives were to: (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working HSCT aerodynamics. In particular, single and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program.

  19. Aerodynamic effects of flexibility in flapping wings

    PubMed Central

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P.

    2010-01-01

    Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re ≈ 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small robotic

  20. An Analysis of the Relationship Between the Form and Function of Educational Objectives.

    ERIC Educational Resources Information Center

    Langley, Lorita

    The purposes of the study were to determine what relationships between form and function of educational objectives can be identified in curriculum literature, and what philosophical beliefs in terms of the axiology of curriculum design are compatible with various combinations of form and function of objectives. A search of the literature yielded…

  1. The Slippery Road from Actions on Objects to Functions and Variables

    ERIC Educational Resources Information Center

    Paz, Tamar; Leron, Uri

    2009-01-01

    Functions are all around us, disguised as actions on concrete objects. Composition of functions, too, is all around us, because these actions can be performed in succession, the output of one serving as the input for the next. In terms of Gray and Tall's (2001) "embodied objects" or Lakoff and Nunez's (2000) "mathematical idea analysis," this…

  2. Function Follows Form: Activation of Shape and Function Features during Object Identification

    ERIC Educational Resources Information Center

    Yee, Eiling; Huffstetler, Stacy; Thompson-Schill, Sharon L.

    2011-01-01

    Most theories of semantic memory characterize knowledge of a given object as comprising a set of semantic features. But how does conceptual activation of these features proceed during object identification? We present the results of a pair of experiments that demonstrate that object recognition is a dynamically unfolding process in which function…

  3. 1997 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 1; Configuration Aerodynamics

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1999-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Aerodynamic Performance Workshop on February 25-28, 1997. The workshop was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in area of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, Flight Controls, Supersonic Laminar Flow Control, and Sonic Boom Prediction. The workshop objectives were to (1) report the progress and status of HSCT aerodyamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientist and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT Motion Simulator results were presented along with executive summaries for all the Aerodynamic Performance technology areas.

  4. (Aerodynamic focusing of particles and heavy molecules)

    SciTech Connect

    de la Mora, J.F.

    1990-01-08

    By accelerating a gas containing suspended particles or large molecules through a converging nozzle, the suspended species may be focused and therefore used to write fine lines on a surface. Our objective was to study the limits on how narrow this focal region could be as a function of particle size. We find that, for monodisperse particles with masses m{sub p} some 3.6 {times} 10{sup 5} times larger than the molecular mass m of the carrier gas (diameters above some 100{angstrom}), there is no fundamental obstacle to directly write submicron features. However, this conclusion has been verified experimentally only with particles larger than 0.1 {mu}m. Experimental, theoretical and numerical studies on the defocusing role of Brownian motion for very small particles or heavy molecules have shown that high resolution (purely aerodynamic) focusing is impossible with volatile molecules whose masses are typically smaller than 1000 Dalton. For these, the minimal focal diameter after optimization appears to be 5{radical}(m/m{sub p}) times the nozzle diameter d{sub n}. But combinations of focused lasers and aerodynamic focusing appear as promising for direct writing with molecular precursors. Theoretical and numerical schemes capable of predicting the evolution of the focusing beam, including Brownian motion effects, have been developed, although further numerical work would be desirable. 11 refs.

  5. Numerical Aerodynamic Simulation

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An overview of historical and current numerical aerodynamic simulation (NAS) is given. The capabilities and goals of the Numerical Aerodynamic Simulation Facility are outlined. Emphasis is given to numerical flow visualization and its applications to structural analysis of aircraft and spacecraft bodies. The uses of NAS in computational chemistry, engine design, and galactic evolution are mentioned.

  6. Uncertainty in Computational Aerodynamics

    NASA Technical Reports Server (NTRS)

    Luckring, J. M.; Hemsch, M. J.; Morrison, J. H.

    2003-01-01

    An approach is presented to treat computational aerodynamics as a process, subject to the fundamental quality assurance principles of process control and process improvement. We consider several aspects affecting uncertainty for the computational aerodynamic process and present a set of stages to determine the level of management required to meet risk assumptions desired by the customer of the predictions.

  7. Computation of dragonfly aerodynamics

    NASA Astrophysics Data System (ADS)

    Gustafson, Karl; Leben, Robert

    1991-04-01

    Dragonflies are seen to hover and dart, seemingly at will and in remarkably nimble fashion, with great bursts of speed and effectively discontinuous changes of direction. In their short lives, their gossamer flight provides us with glimpses of an aerodynamics of almost extraterrestrial quality. Here we present the first computer simulations of such aerodynamics.

  8. The Development of Object Function and Manipulation Knowledge: Evidence from a Semantic Priming Study.

    PubMed

    Collette, Cynthia; Bonnotte, Isabelle; Jacquemont, Charlotte; Kalénine, Solène; Bartolo, Angela

    2016-01-01

    Object semantics include object function and manipulation knowledge. Function knowledge refers to the goal attainable by using an object (e.g., the function of a key is to open or close a door) while manipulation knowledge refers to gestures one has to execute to use an object appropriately (e.g., a key is held between the thumb and the index, inserted into the door lock and then turned). To date, several studies have assessed function and manipulation knowledge in brain lesion patients as well as in healthy adult populations. In patients with left brain damage, a double dissociation between these two types of knowledge has been reported; on the other hand, behavioral studies in healthy adults show that function knowledge is processed faster than manipulation knowledge. Empirical evidence has shown that object interaction in children differs from that in adults, suggesting that the access to function and manipulation knowledge in children might also differ. To investigate the development of object function and manipulation knowledge, 51 typically developing 8-9-10 year-old children and 17 healthy young adults were tested on a naming task associated with a semantic priming paradigm (190-ms SOA; prime duration: 90 ms) in which a series of line drawings of manipulable objects were used. Target objects could be preceded by three priming contexts: related (e.g., knife-scissors for function; key-screwdriver for manipulation), unrelated but visually similar (e.g., glasses-scissors; baseball bat-screwdriver), and purely unrelated (e.g., die-scissors; tissue-screwdriver). Results showed a different developmental pattern of function and manipulation priming effects. Function priming effects were not present in children and emerged only in adults, with faster naming responses for targets preceded by objects sharing the same function. In contrast, manipulation priming effects were already present in 8-year-olds with faster naming responses for targets preceded by objects

  9. The Development of Object Function and Manipulation Knowledge: Evidence from a Semantic Priming Study

    PubMed Central

    Collette, Cynthia; Bonnotte, Isabelle; Jacquemont, Charlotte; Kalénine, Solène; Bartolo, Angela

    2016-01-01

    Object semantics include object function and manipulation knowledge. Function knowledge refers to the goal attainable by using an object (e.g., the function of a key is to open or close a door) while manipulation knowledge refers to gestures one has to execute to use an object appropriately (e.g., a key is held between the thumb and the index, inserted into the door lock and then turned). To date, several studies have assessed function and manipulation knowledge in brain lesion patients as well as in healthy adult populations. In patients with left brain damage, a double dissociation between these two types of knowledge has been reported; on the other hand, behavioral studies in healthy adults show that function knowledge is processed faster than manipulation knowledge. Empirical evidence has shown that object interaction in children differs from that in adults, suggesting that the access to function and manipulation knowledge in children might also differ. To investigate the development of object function and manipulation knowledge, 51 typically developing 8-9-10 year-old children and 17 healthy young adults were tested on a naming task associated with a semantic priming paradigm (190-ms SOA; prime duration: 90 ms) in which a series of line drawings of manipulable objects were used. Target objects could be preceded by three priming contexts: related (e.g., knife-scissors for function; key-screwdriver for manipulation), unrelated but visually similar (e.g., glasses-scissors; baseball bat-screwdriver), and purely unrelated (e.g., die-scissors; tissue-screwdriver). Results showed a different developmental pattern of function and manipulation priming effects. Function priming effects were not present in children and emerged only in adults, with faster naming responses for targets preceded by objects sharing the same function. In contrast, manipulation priming effects were already present in 8-year-olds with faster naming responses for targets preceded by objects

  10. The impact of objective function selection on the influence of individual data points

    NASA Astrophysics Data System (ADS)

    Wright, David; Thyer, Mark; Westra, Seth; McInerney, David

    2016-04-01

    Across the field of hydrology practitioners apply a range of objective functions which are selected based upon the intended model application and suitability of the objective function assumptions to the data in question. Despite most objective functions providing fundamentally different calibration results there are currently limited methods for comparison of alternatives. Influence diagnostics quantify the impact of individual data points on model performance, parameters and predictions. The goal of this study is to use compare four commonly applied objective functions in hydrology using influence diagnostics to provide insights on how objective function selection changes the influence of individual data points on model calibration. The specific aims are to: 1) explore the impact on magnitude of influence of objective functions, 2) investigate similarities between influential points identified by objective functions and, 3) categorise flows that are influential under objective functions. We use case-deletion influence diagnostics to examine four objective functions: Standard Least Squares (SLS), Weighted Least Squares (WLS), Log transformed flows (LOG) and the Kling-Gupta Efficiency (KGE). We apply these objective functions to six scenarios: two conceptual hydrological models (GR4J and IHACRES) across three catchment case studies with varying runoff coefficients (0.14 to 0.57). We quantify influence using the case-deletion relative change in flow metrics: mean flow prediction, maximum flow prediction, and the 10th percentile low flow prediction. The results show that when using objective functions SLS and KGE influential data points have larger magnitude influence (maximum of 10% change in the flow metrics across all data points for both objective functions) than heteroscedastic WLS and LOG (WLS maximum of 8% and LOG maximum of 6% change in the flow metrics). SLS and KGE identify similar influential points (75% of the most influential points are common to both

  11. The Krigifier: A Procedure for Generating Pseudorandom Nonlinear Objective Functions for Computational Experimentation

    NASA Technical Reports Server (NTRS)

    Trosset, Michael W.

    1999-01-01

    Comprehensive computational experiments to assess the performance of algorithms for numerical optimization require (among other things) a practical procedure for generating pseudorandom nonlinear objective functions. We propose a procedure that is based on the convenient fiction that objective functions are realizations of stochastic processes. This report details the calculations necessary to implement our procedure for the case of certain stationary Gaussian processes and presents a specific implementation in the statistical programming language S-PLUS.

  12. Matching and Naming Objects by Shape or Function: Age and Context Effects in Preschool Children.

    ERIC Educational Resources Information Center

    Deak, Gedeon O.; Ray, Shanna D.; Pick, Anne D.

    2002-01-01

    Three experiments tested 3- and 4-year-olds' use of abstract principles to classify and label objects by shape or function. Findings indicated that 4-year-olds readily adopted either rule when instructed to match objects by shape or function, but 3-year-olds followed only the shape rule. Without a rule, 4-year-olds tended to match by shape unless…

  13. Functionality of Objectives in the Program and Education Plans of Persons with Mental Retardation.

    ERIC Educational Resources Information Center

    Keyes, Joseph B.; Karst, Ralph R.

    This study examined the relationship between the functionality of training objectives established in Individual Program Plans (IPPs) and Individual Education Plans (IEPs) of persons with severe and profound mental retardation and different service delivery environments. Each training objective in the IPPs and IEPs of 78 individuals was classified…

  14. Action Semantic Knowledge about Objects Is Supported by Functional Motor Activation

    ERIC Educational Resources Information Center

    van Elk, Michiel; van Schie, Hein T.; Bekkering, Harold

    2009-01-01

    The present study assessed the functional organization of action semantics by asking subjects to categorize pictures of an actor holding objects with a correct or incorrect grip at either a correct or incorrect goal location. Overall, reaction times were slower if the object was presented with an inappropriate posture, and this effect was stronger…

  15. Functional Dissociations within the Ventral Object Processing Pathway: Cognitive Modules or a Hierarchical Continuum?

    ERIC Educational Resources Information Center

    Cowell, Rosemary A.; Bussey, Timothy J.; Saksida, Lisa M.

    2010-01-01

    We examined the organization and function of the ventral object processing pathway. The prevailing theoretical approach in this field holds that the ventral object processing stream has a modular organization, in which visual perception is carried out in posterior regions and visual memory is carried out, independently, in the anterior temporal…

  16. ERPs Differentially Reflect Automatic and Deliberate Processing of the Functional Manipulability of Objects.

    PubMed

    Madan, Christopher R; Chen, Yvonne Y; Singhal, Anthony

    2016-01-01

    It is known that the functional properties of an object can interact with perceptual, cognitive, and motor processes. Previously we have found that a between-subjects manipulation of judgment instructions resulted in different manipulability-related memory biases in an incidental memory test. To better understand this effect we recorded electroencephalography (EEG) while participants made judgments about images of objects that were either high or low in functional manipulability (e.g., hammer vs. ladder). Using a between-subjects design, participants judged whether they had seen the object recently (Personal Experience), or could manipulate the object using their hand (Functionality). We focused on the P300 and slow-wave event-related potentials (ERPs) as reflections of attentional allocation. In both groups, we observed higher P300 and slow wave amplitudes for high-manipulability objects at electrodes Pz and C3. As P300 is thought to reflect bottom-up attentional processes, this may suggest that the processing of high-manipulability objects recruited more attentional resources. Additionally, the P300 effect was greater in the Functionality group. A more complex pattern was observed at electrode C3 during slow wave: processing the high-manipulability objects in the Functionality instruction evoked a more positive slow wave than in the other three conditions, likely related to motor simulation processes. These data provide neural evidence that effects of manipulability on stimulus processing are further mediated by automatic vs. deliberate motor-related processing. PMID:27536224

  17. ERPs Differentially Reflect Automatic and Deliberate Processing of the Functional Manipulability of Objects

    PubMed Central

    Madan, Christopher R.; Chen, Yvonne Y.; Singhal, Anthony

    2016-01-01

    It is known that the functional properties of an object can interact with perceptual, cognitive, and motor processes. Previously we have found that a between-subjects manipulation of judgment instructions resulted in different manipulability-related memory biases in an incidental memory test. To better understand this effect we recorded electroencephalography (EEG) while participants made judgments about images of objects that were either high or low in functional manipulability (e.g., hammer vs. ladder). Using a between-subjects design, participants judged whether they had seen the object recently (Personal Experience), or could manipulate the object using their hand (Functionality). We focused on the P300 and slow-wave event-related potentials (ERPs) as reflections of attentional allocation. In both groups, we observed higher P300 and slow wave amplitudes for high-manipulability objects at electrodes Pz and C3. As P300 is thought to reflect bottom-up attentional processes, this may suggest that the processing of high-manipulability objects recruited more attentional resources. Additionally, the P300 effect was greater in the Functionality group. A more complex pattern was observed at electrode C3 during slow wave: processing the high-manipulability objects in the Functionality instruction evoked a more positive slow wave than in the other three conditions, likely related to motor simulation processes. These data provide neural evidence that effects of manipulability on stimulus processing are further mediated by automatic vs. deliberate motor-related processing. PMID:27536224

  18. A two-level parallel direct search implementation for arbitrarily sized objective functions

    SciTech Connect

    Hutchinson, S.A.; Shadid, N.; Moffat, H.K.

    1994-12-31

    In the past, many optimization schemes for massively parallel computers have attempted to achieve parallel efficiency using one of two methods. In the case of large and expensive objective function calculations, the optimization itself may be run in serial and the objective function calculations parallelized. In contrast, if the objective function calculations are relatively inexpensive and can be performed on a single processor, then the actual optimization routine itself may be parallelized. In this paper, a scheme based upon the Parallel Direct Search (PDS) technique is presented which allows the objective function calculations to be done on an arbitrarily large number (p{sub 2}) of processors. If, p, the number of processors available, is greater than or equal to 2p{sub 2} then the optimization may be parallelized as well. This allows for efficient use of computational resources since the objective function calculations can be performed on the number of processors that allow for peak parallel efficiency and then further speedup may be achieved by parallelizing the optimization. Results are presented for an optimization problem which involves the solution of a PDE using a finite-element algorithm as part of the objective function calculation. The optimum number of processors for the finite-element calculations is less than p/2. Thus, the PDS method is also parallelized. Performance comparisons are given for a nCUBE 2 implementation.

  19. The aerodynamics of propellers

    NASA Astrophysics Data System (ADS)

    Wald, Quentin R.

    2006-02-01

    The theory and the design of propellers of minimum induced loss is treated. The pioneer analysis of this problem was presented more than half a century ago by Theodorsen, but obscurities in his treatment and inaccuracies and limited coverage in his tables of the Goldstein circulation function for helicoidal vortex sheets have not been remedied until the present work which clarifies and extends his work. The inverse problem, the prediction of the performance of a given propeller of arbitrary form, is also treated. The theory of propellers of minimum energy loss is dependent on considerations of a regular helicoidal trailing vortex sheet; consequently, a more detailed discussion of the dynamics of vortex sheets and the consequences of their instability and roll up is presented than is usually found in treatments of propeller aerodynamics. Complete and accurate tables of the circulation function are presented. Interference effects between a fuselage or a nacelle and the propeller are considered. The regimes of propeller, vortex ring, and windmill operation are characterized.

  20. Mathematical modeling of the aerodynamic characteristics in flight dynamics

    NASA Technical Reports Server (NTRS)

    Tobak, M.; Chapman, G. T.; Schiff, L. B.

    1984-01-01

    Basic concepts involved in the mathematical modeling of the aerodynamic response of an aircraft to arbitrary maneuvers are reviewed. The original formulation of an aerodynamic response in terms of nonlinear functionals is shown to be compatible with a derivation based on the use of nonlinear functional expansions. Extensions of the analysis through its natural connection with ideas from bifurcation theory are indicated.

  1. English Function Catalog and Rolebooks. Method for Determining Language Objectives and Criteria, Volume IV.

    ERIC Educational Resources Information Center

    Setzler, Hubert H., Jr.; And Others

    An English function catalog and rolebooks are presented as part of the communication/language objectives-based system (C/LOBS) that supports the front-end analysis efforts of the Defense Language Institute Foreign Language Center. The C/LOBS project, which is described in 13 volumes and an executive summary, functions as a subsystem of the…

  2. Aerodynamic Lifting Force.

    ERIC Educational Resources Information Center

    Weltner, Klaus

    1990-01-01

    Describes some experiments showing both qualitatively and quantitatively that aerodynamic lift is a reaction force. Demonstrates reaction forces caused by the acceleration of an airstream and the deflection of an airstream. Provides pictures of demonstration apparatus and mathematical expressions. (YP)

  3. Launch vehicle aerodynamic data base development comparison with flight data

    NASA Technical Reports Server (NTRS)

    Hamilton, J. T.; Wallace, R. O.; Dill, C. C.

    1983-01-01

    The aerodynamic development plan for the Space Shuttle integrated vehicle had three major objectives. The first objective was to support the evolution of the basic configuration by establishing aerodynamic impacts to various candidate configurations. The second objective was to provide continuing evaluation of the basic aerodynamic characteristics in order to bring about a mature data base. The third task was development of the element and component aerodynamic characteristics and distributed air loads data to support structural loads analyses. The complexity of the configurations rendered conventional analytic methods of little use and therefore required extensive wind tunnel testing of detailed complex models. However, the ground testing and analyses did not predict the aerodynamic characteristics that were extracted from the Space Shuttle flight test program. Future programs that involve the use of vehicles similar to the Space Shuttle should be concerned with the complex flow fields characteristics of these types of complex configurations.

  4. Aerodynamic Shutoff Valve

    NASA Technical Reports Server (NTRS)

    Horstman, Raymond H.

    1992-01-01

    Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

  5. Aerodynamics of Heavy Vehicles

    NASA Astrophysics Data System (ADS)

    Choi, Haecheon; Lee, Jungil; Park, Hyungmin

    2014-01-01

    We present an overview of the aerodynamics of heavy vehicles, such as tractor-trailers, high-speed trains, and buses. We introduce three-dimensional flow structures around simplified model vehicles and heavy vehicles and discuss the flow-control devices used for drag reduction. Finally, we suggest important unsteady flow structures to investigate for the enhancement of aerodynamic performance and future directions for experimental and numerical approaches.

  6. Aerodynamic Decelerators for Planetary Exploration: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Cruz, Juna R.; Lingard, J. Stephen

    2006-01-01

    In this paper, aerodynamic decelerators are defined as textile devices intended to be deployed at Mach numbers below five. Such aerodynamic decelerators include parachutes and inflatable aerodynamic decelerators (often known as ballutes). Aerodynamic decelerators play a key role in the Entry, Descent, and Landing (EDL) of planetary exploration vehicles. Among the functions performed by aerodynamic decelerators for such vehicles are deceleration (often from supersonic to subsonic speeds), minimization of descent rate, providing specific descent rates (so that scientific measurements can be obtained), providing stability (drogue function - either to prevent aeroshell tumbling or to meet instrumentation requirements), effecting further aerodynamic decelerator system deployment (pilot function), providing differences in ballistic coefficients of components to enable separation events, and providing height and timeline to allow for completion of the EDL sequence. Challenging aspects in the development of aerodynamic decelerators for planetary exploration missions include: deployment in the unusual combination of high Mach numbers and low dynamic pressures, deployment in the wake behind a blunt-body entry vehicle, stringent mass and volume constraints, and the requirement for high drag and stability. Furthermore, these aerodynamic decelerators must be qualified for flight without access to the exotic operating environment where they are expected to operate. This paper is an introduction to the development and application of aerodynamic decelerators for robotic planetary exploration missions (including Earth sample return missions) from the earliest work in the 1960s to new ideas and technologies with possible application to future missions. An extensive list of references is provided for additional study.

  7. Objective functions of online weight noise injection training algorithms for MLPs.

    PubMed

    Ho, Kevin; Leung, Chi-Sing; Sum, John

    2011-02-01

    Injecting weight noise during training has been a simple strategy to improve the fault tolerance of multilayer perceptrons (MLPs) for almost two decades, and several online training algorithms have been proposed in this regard. However, there are some misconceptions about the objective functions being minimized by these algorithms. Some existing results misinterpret that the prediction error of a trained MLP affected by weight noise is equivalent to the objective function of a weight noise injection algorithm. In this brief, we would like to clarify these misconceptions. Two weight noise injection scenarios will be considered: one is based on additive weight noise injection and the other is based on multiplicative weight noise injection. To avoid the misconceptions, we use their mean updating equations to analyze the objective functions. For injecting additive weight noise during training, we show that the true objective function is identical to the prediction error of a faulty MLP whose weights are affected by additive weight noise. It consists of the conventional mean square error and a smoothing regularizer. For injecting multiplicative weight noise during training, we show that the objective function is different from the prediction error of a faulty MLP whose weights are affected by multiplicative weight noise. With our results, some existing misconceptions regarding MLP training with weight noise injection can now be resolved. PMID:21189237

  8. On Improving Efficiency of Differential Evolution for Aerodynamic Shape Optimization Applications

    NASA Technical Reports Server (NTRS)

    Madavan, Nateri K.

    2004-01-01

    Differential Evolution (DE) is a simple and robust evolutionary strategy that has been provEn effective in determining the global optimum for several difficult optimization problems. Although DE offers several advantages over traditional optimization approaches, its use in applications such as aerodynamic shape optimization where the objective function evaluations are computationally expensive is limited by the large number of function evaluations often required. In this paper various approaches for improving the efficiency of DE are reviewed and discussed. Several approaches that have proven effective for other evolutionary algorithms are modified and implemented in a DE-based aerodynamic shape optimization method that uses a Navier-Stokes solver for the objective function evaluations. Parallelization techniques on distributed computers are used to reduce turnaround times. Results are presented for standard test optimization problems and for the inverse design of a turbine airfoil. The efficiency improvements achieved by the different approaches are evaluated and compared.

  9. On Improving Efficiency of Differential Evolution for Aerodynamic Shape Optimization Applications

    NASA Technical Reports Server (NTRS)

    Madavan, Nateri K.

    2004-01-01

    Differential Evolution (DE) is a simple and robust evolutionary strategy that has been proven effective in determining the global optimum for several difficult optimization problems. Although DE offers several advantages over traditional optimization approaches, its use in applications such as aerodynamic shape optimization where the objective function evaluations are computationally expensive is limited by the large number of function evaluations often required. In this paper various approaches for improving the efficiency of DE are reviewed and discussed. These approaches are implemented in a DE-based aerodynamic shape optimization method that uses a Navier-Stokes solver for the objective function evaluations. Parallelization techniques on distributed computers are used to reduce turnaround times. Results are presented for the inverse design of a turbine airfoil. The efficiency improvements achieved by the different approaches are evaluated and compared.

  10. Aerodynamic optimum design of transonic turbine cascades using Genetic Algorithms

    NASA Astrophysics Data System (ADS)

    Li, Jun; Feng, Zhenping; Chang, Jianzhong; Shen, Zuda

    1997-06-01

    This paper presents an aerodynamic optimum design method for transonic turbine cascades based on the Genetic Algorithms coupled to the inviscid flow Euler solver and the boundary-layer calculation. The Genetic Algorithms control the evolution of a population of cascades towards an optimum design. The fitness value of each string is evaluated using the flow solver. The design procedure has been developed and the behavior of the genetic algorithms has been tested. The objective functions of the design examples are the minimum mean-square deviation between the aimed pressure and computed pressure and the minimum amount of user expertise.

  11. Comparative Study of Popular Objective Functions for Damping Power System Oscillations in Multimachine System

    PubMed Central

    Niamul Islam, Naz; Hannan, M. A.; Shareef, Hussain; Mohamed, Azah; Salam, M. A.

    2014-01-01

    Power oscillation damping controller is designed in linearized model with heuristic optimization techniques. Selection of the objective function is very crucial for damping controller design by optimization algorithms. In this research, comparative analysis has been carried out to evaluate the effectiveness of popular objective functions used in power system oscillation damping. Two-stage lead-lag damping controller by means of power system stabilizers is optimized using differential search algorithm for different objective functions. Linearized model simulations are performed to compare the dominant mode's performance and then the nonlinear model is continued to evaluate the damping performance over power system oscillations. All the simulations are conducted in two-area four-machine power system to bring a detailed analysis. Investigated results proved that multiobjective D-shaped function is an effective objective function in terms of moving unstable and lightly damped electromechanical modes into stable region. Thus, D-shape function ultimately improves overall system damping and concurrently enhances power system reliability. PMID:24977210

  12. An objective function for Hebbian self-limiting synaptic plasticity rules

    NASA Astrophysics Data System (ADS)

    Gros, Claudius; Eckmann, Samuel; Echeveste, Rodrigo

    Objective functions, formulated in terms of information theoretical measures with respect to the input and output probability distributions, provide a useful framework for the formulation of guiding principles for information processing systems, such as neural networks. In the present work, a guiding principle for neural plasticity is formulated in terms of an objective function expressed as the Fisher information with respect to an operator that we denote as the synaptic flux. By minimization of this objective function, we obtain Hebbian self-limiting synaptic plasticity rules, avoiding unbounded weight growth. Furthermore, we show how the rules are selective to directions of maximal negative excess kurtosis, making them suitable for independent component analysis. As an application, the non-linear bars problem is studied, in which each neuron is presented with a non-linear superposition of horizontal and vertical bars. We show that, under the here presented rules, the neurons are able to find the independent components of the input.

  13. Comparative study of objective functions to overcome noise and bandwidth limitations in full waveform inversion

    NASA Astrophysics Data System (ADS)

    Jiménez Tejero, C. E.; Dagnino, D.; Sallarès, V.; Ranero, C. R.

    2015-10-01

    Ongoing works on full waveform inversion (FWI) are yielding an increasing number of objective functions as alternative to the traditional L2-waveform. These studies aim at designing more robust functions and inversion strategies to reduce the intrinsic dependence of the FWI results on (1) the initial model and (2) the lowest frequency present in field data. In this work, we perform a comparative study of five objective functions in time domain under a common 2-D-acoustic FWI scheme using the Marmousi model as benchmark. In particular, we compare results obtained with L2-based functions that consider the minimization of different wave attributes; the waveform-based, non-integration-method; instantaneous envelope; a modified version of the wrapped instantaneous phase and an improved version of the cross-correlation travel time (CCTT) method; and hybrid strategies combining some of them. We evaluate the robustness of these functionals as a function of their performance with and without low frequencies in the data and the presence of random white Gaussian noise. Our results reveal promising strategies to invert noisy data with limited low-frequency content (≥4 Hz), which is the single strategy using the instantaneous phase objective function followed by the hybrid strategies using the instantaneous phase or CCTT as initial models, in particular the combinations [I. Phase + Waveform], [CCTT + Waveform] and [CCTT + I. Phase].

  14. Calculation of the twilight visibility function of near-sun objects

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.

    1976-01-01

    The visibility function, defined here as the magnitude difference between the excess brightness of a given object and that of the background sky, of near-sun objects during twilight is obtained from a general calculation which considers the twilight sky background, atmospheric extinction, and night glow. Visibility curves are computed for a number of cases in which observations have been recorded, particularly that of comet Kohoutek. For this object, the computed visibility maxima agree well in time with the reported times of observation.

  15. Determination of the object surface function by structured light: application to the study of spinal deformities

    NASA Astrophysics Data System (ADS)

    Buendía, M.; Salvador, R.; Cibrián, R.; Laguia, M.; Sotoca, J. M.

    1999-01-01

    The projection of structured light is a technique frequently used to determine the surface shape of an object. In this paper, a new procedure is described that efficiently resolves the correspondence between the knots of the projected grid and those obtained on the object when the projection is made. The method is based on the use of three images of the projected grid. In two of them the grid is projected over a flat surface placed, respectively, before and behind the object; both images are used for calibration. In the third image the grid is projected over the object. It is not reliant on accurate determination of the camera and projector pair relative to the grid and object. Once the method is calibrated, we can obtain the surface function by just analysing the projected grid on the object. The procedure is especially suitable for the study of objects without discontinuities or large depth gradients. It can be employed for determining, in a non-invasive way, the patient's back surface function. Symmetry differences permit a quantitative diagnosis of spinal deformities such as scoliosis.

  16. Tactical missile aerodynamics

    NASA Technical Reports Server (NTRS)

    Hemsch, Michael J. (Editor); Nielsen, Jack N. (Editor)

    1986-01-01

    The present conference on tactical missile aerodynamics discusses autopilot-related aerodynamic design considerations, flow visualization methods' role in the study of high angle-of-attack aerodynamics, low aspect ratio wing behavior at high angle-of-attack, supersonic airbreathing propulsion system inlet design, missile bodies with noncircular cross section and bank-to-turn maneuvering capabilities, 'waverider' supersonic cruise missile concepts and design methods, asymmetric vortex sheding phenomena from bodies-of-revolution, and swept shock wave/boundary layer interaction phenomena. Also discussed are the assessment of aerodynamic drag in tactical missiles, the analysis of supersonic missile aerodynamic heating, the 'equivalent angle-of-attack' concept for engineering analysis, the vortex cloud model for body vortex shedding and tracking, paneling methods with vorticity effects and corrections for nonlinear compressibility, the application of supersonic full potential method to missile bodies, Euler space marching methods for missiles, three-dimensional missile boundary layers, and an analysis of exhaust plumes and their interaction with missile airframes.

  17. fMRI-adaptation evidence of overlapping neural representations for objects related in function or manipulation.

    PubMed

    Yee, Eiling; Drucker, Daniel M; Thompson-Schill, Sharon L

    2010-04-01

    Sensorimotor-based theories of semantic memory contend that semantic information about an object is represented in the neural substrate invoked when we perceive or interact with it. We used fMRI adaptation to test this prediction, measuring brain activation as participants read pairs of words. Pairs shared function (flashlight-lantern), shape (marble-grape), both (pencil-pen), were unrelated (saucer-needle), or were identical (drill-drill). We observed adaptation for pairs with both function and shape similarity in left premotor cortex. Further, degree of function similarity was correlated with adaptation in three regions: two in the left temporal lobe (left medial temporal lobe, left middle temporal gyrus), which has been hypothesized to play a role in mutimodal integration, and one in left superior frontal gyrus. We also found that degree of manipulation (i.e., action) and function similarity were both correlated with adaptation in two regions: left premotor cortex and left intraparietal sulcus (involved in guiding actions). Additional considerations suggest that the adaptation in these two regions was driven by manipulation similarity alone; thus, these results imply that manipulation information about objects is encoded in brain regions involved in performing or guiding actions. Unexpectedly, these same two regions showed increased activation (rather than adaptation) for objects similar in shape. Overall, we found evidence (in the form of adaptation) that objects that share semantic features have overlapping representations. Further, the particular regions of overlap provide support for the existence of both sensorimotor and amodal/multimodal representations. PMID:20034582

  18. A parallel approach of COFFEE objective function to multiple sequence alignment

    NASA Astrophysics Data System (ADS)

    Zafalon, G. F. D.; Visotaky, J. M. V.; Amorim, A. R.; Valêncio, C. R.; Neves, L. A.; de Souza, R. C. G.; Machado, J. M.

    2015-09-01

    The computational tools to assist genomic analyzes show even more necessary due to fast increasing of data amount available. With high computational costs of deterministic algorithms for sequence alignments, many works concentrate their efforts in the development of heuristic approaches to multiple sequence alignments. However, the selection of an approach, which offers solutions with good biological significance and feasible execution time, is a great challenge. Thus, this work aims to show the parallelization of the processing steps of MSA-GA tool using multithread paradigm in the execution of COFFEE objective function. The standard objective function implemented in the tool is the Weighted Sum of Pairs (WSP), which produces some distortions in the final alignments when sequences sets with low similarity are aligned. Then, in studies previously performed we implemented the COFFEE objective function in the tool to smooth these distortions. Although the nature of COFFEE objective function implies in the increasing of execution time, this approach presents points, which can be executed in parallel. With the improvements implemented in this work, we can verify the execution time of new approach is 24% faster than the sequential approach with COFFEE. Moreover, the COFFEE multithreaded approach is more efficient than WSP, because besides it is slightly fast, its biological results are better.

  19. Using Form and Function Analogy Object Boxes to Teach Human Body Systems

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Furletti, Charles

    2004-01-01

    This study compares the use of form and function analogy object boxes to more traditional lecture and worksheet instruction during a 10th-grade unit on human body systems. The study was conducted with two classes (N = 32) of mixed ability students at a high-needs rural high school in central New York State. The study used a pretest/posttest…

  20. fMRI-Adaptation Evidence of Overlapping Neural Representations for Objects Related in Function or Manipulation

    PubMed Central

    Yee, Eiling; Drucker, Daniel M.; Thompson-Schill, Sharon L.

    2010-01-01

    Sensorimotor-based theories of semantic memory contend that semantic information about an object is represented in the neural substrate invoked when we perceive or interact with it. We used fMRI adaptation to test this prediction, measuring brain activation as participants read pairs of words. Pairs shared function (flashlight–lantern), shape (marble–grape), both (pencil–pen), were unrelated (saucer–needle), or were identical (drill–drill). We observed adaptation for pairs with both function and shape similarity in left premotor cortex. Further, degree of function similarity was correlated with adaptation in three regions: two in the left temporal lobe (left medial temporal lobe, left middle temporal gyrus), which has been hypothesized to play a role in mutimodal integration, and one in left superior frontal gyrus. We also found that degree of manipulation (i.e., action) and function similarity were both correlated with adaptation in two regions: left premotor cortex and left intraparietal sulcus (involved in guiding actions). Additional considerations suggest that the adaptation in these two regions was driven by manipulation similarity alone; thus, these results imply that manipulation information about objects is encoded in brain regions involved in performing or guiding actions. Unexpectedly, these same two regions showed increased activation (rather than adaptation) for objects similar in shape. Overall, we found evidence (in the form of adaptation) that objects that share semantic features have overlapping representations. Further, the particular regions of overlap provide support for the existence of both sensorimotor and amodal/multimodal representations. PMID:20034582

  1. Second Graders Learn Animal Adaptations through Form and Function Analogy Object Boxes

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Baldwin, Samantha; Schell, Robert

    2008-01-01

    This study examined the use of form and function analogy object boxes to teach second graders (n = 21) animal adaptations. The study used a pretest-posttest design to examine animal adaptation content learned through focused analogy activities as compared with reading and Internet searches for information about adaptations of animals followed by…

  2. Fuzzy Multi-Objective Transportation Planning with Modified S-Curve Membership Function

    NASA Astrophysics Data System (ADS)

    Peidro, D.; Vasant, P.

    2009-08-01

    In this paper, the S-Curve membership function methodology is used in a transportation planning decision (TPD) problem. An interactive method for solving multi-objective TPD problems with fuzzy goals, available supply and forecast demand is developed. The proposed method attempts simultaneously to minimize the total production and transportation costs and the total delivery time with reference to budget constraints and available supply, machine capacities at each source, as well as forecast demand and warehouse space constraints at each destination. We compare in an industrial case the performance of S-curve membership functions, representing uncertainty goals and constraints in TPD problems, with linear membership functions.

  3. Applied computational aerodynamics

    SciTech Connect

    Henne, P.A.

    1990-01-01

    The present volume discusses the original development of the panel method, the mapping solutions and singularity distributions of linear potential schemes, the capabilities of full-potential, Euler, and Navier-Stokes schemes, the use of the grid-generation methodology in applied aerodynamics, subsonic airfoil design, inverse airfoil design for transonic applications, the divergent trailing-edge airfoil innovation in CFD, Euler and potential computational results for selected aerodynamic configurations, and the application of CFD to wing high-lift systems. Also discussed are high-lift wing modifications for an advanced-capability EA-6B aircraft, Navier-Stokes methods for internal and integrated propulsion system flow predictions, the use of zonal techniques for analysis of rotor-stator interaction, CFD applications to complex configurations, CFD applications in component aerodynamic design of the V-22, Navier-Stokes computations of a complete F-16, CFD at supersonic/hypersonic speeds, and future CFD developments.

  4. Photogrammetry of a Hypersonic Inflatable Aerodynamic Decelerator

    NASA Technical Reports Server (NTRS)

    Kushner, Laura Kathryn; Littell, Justin D.; Cassell, Alan M.

    2013-01-01

    In 2012, two large-scale models of a Hypersonic Inflatable Aerodynamic decelerator were tested in the National Full-Scale Aerodynamic Complex at NASA Ames Research Center. One of the objectives of this test was to measure model deflections under aerodynamic loading that approximated expected flight conditions. The measurements were acquired using stereo photogrammetry. Four pairs of stereo cameras were mounted inside the NFAC test section, each imaging a particular section of the HIAD. The views were then stitched together post-test to create a surface deformation profile. The data from the photogram- metry system will largely be used for comparisons to and refinement of Fluid Structure Interaction models. This paper describes how a commercial photogrammetry system was adapted to make the measurements and presents some preliminary results.

  5. Color-Function Categories that Prime Infants to Use Color Information in an Object Individuation Task

    PubMed Central

    Wilcox, Teresa; Woods, Rebecca; Chapa, Catherine

    2008-01-01

    There is evidence for developmental hierarchies in the type of information to which infants attend when reasoning about objects. Investigators have questioned the origin of these hierarchies and how infants come to identify new sources of information when reasoning about objects. The goal of the present experiments was to shed light on this debate by identifying conditions under which infants’ sensitivity to color information, which is slow to emerge, could be enhanced in an object individuation task. The outcome of Experiment 1 confirmed and extended previous reports that 9.5-month-olds can be primed, through exposure to events in which the color of an object predicts its function, to attend to color differences in a subsequent individuation task. The outcomes of Experiments 2 to 4 revealed age-related changes in the nature of the representations that support color priming. This is exemplified by three main findings. First, the representations that are formed during the color-function events are relatively specific. That is, infants are primed to use the color difference seen in the color-function events to individuate objects in the test events, but not other color differences. Second, 9.5-month-olds can be led to form more abstract event representations, and then generalize to other colors in the test events if they are shown multiple pairs of colors in the color-function events. Third, slightly younger 9-month-olds also can be led to form more inclusive categories with multiple color pairs, but only when they are allowed to directly compare the exemplars in each color pair during the present events. These results shed light on the development of categorization abilities, cognitive mechanisms that support color-function priming, and the kinds of experiences that can increase infants’ sensitivity to color information. PMID:18378222

  6. Object detection and classification using image moment functions in the applied to video and imagery analysis

    NASA Astrophysics Data System (ADS)

    Mise, Olegs; Bento, Stephen

    2013-05-01

    This paper proposes an object detection algorithm and a framework based on a combination of Normalized Central Moment Invariant (NCMI) and Normalized Geometric Radial Moment (NGRM). The developed framework allows detecting objects with offline pre-loaded signatures and/or using the tracker data in order to create an online object signature representation. The framework has been successfully applied to the target detection and has demonstrated its performance on real video and imagery scenes. In order to overcome the implementation constraints of the low-powered hardware, the developed framework uses a combination of image moment functions and utilizes a multi-layer neural network. The developed framework has been shown to be robust to false alarms on non-target objects. In addition, optimization for fast calculation of the image moments descriptors is discussed. This paper presents an overview of the developed framework and demonstrates its performance on real video and imagery scenes.

  7. Powered-Lift Aerodynamics and Acoustics. [conferences

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Powered lift technology is reviewed. Topics covered include: (1) high lift aerodynamics; (2) high speed and cruise aerodynamics; (3) acoustics; (4) propulsion aerodynamics and acoustics; (5) aerodynamic and acoustic loads; and (6) full-scale and flight research.

  8. Supersonic airplane design optimization method for aerodynamic performance and low sonic boom

    NASA Technical Reports Server (NTRS)

    Cheung, Samson H.; Edwards, Thomas A.

    1992-01-01

    This paper presents a new methodology for the optimization of supersonic airplane designs to meet the dual design objectives of low sonic boom and high aerodynamic performance. Two sets of design parameters are used on an existing High Speed Civil Transport (HSCT) configuration to maximize the aerodynamic performance and minimize the sonic boom under the flight track. One set of the parameters perturbs the camber line of the wing sections to maximize the lift-over-drag ratio (L/D). A preliminary optimization run yielded a 3.75 percent improvement in L/D over a baseline low-boom configuration. The other set of parameters modifies the fuselage area to achieve a target F-function. Starting from an initial configuration with strong bow, wing, and tail shocks, a modified design with a flat-top signature is obtained. The methods presented can easily incorporate other design variables and objective functions. Extensions to the present capability in progress are described.

  9. Hubble Space Telescope Faint Object Camera calculated point-spread functions.

    PubMed

    Lyon, R G; Dorband, J E; Hollis, J M

    1997-03-10

    A set of observed noisy Hubble Space Telescope Faint Object Camera point-spread functions is used to recover the combined Hubble and Faint Object Camera wave-front error. The low-spatial-frequency wave-front error is parameterized in terms of a set of 32 annular Zernike polynomials. The midlevel and higher spatial frequencies are parameterized in terms of set of 891 polar-Fourier polynomials. The parameterized wave-front error is used to generate accurate calculated point-spread functions, both pre- and post-COSTAR (corrective optics space telescope axial replacement), suitable for image restoration at arbitrary wavelengths. We describe the phase-retrieval-based recovery process and the phase parameterization. Resultant calculated precorrection and postcorrection point-spread functions are shown along with an estimate of both pre- and post-COSTAR spherical aberration. PMID:18250862

  10. Aerodynamics of thrust vectoring

    NASA Technical Reports Server (NTRS)

    Tseng, J. B.; Lan, C. Edward

    1989-01-01

    Thrust vectoring as a means to enhance maneuverability and aerodynamic performane of a tactical aircraft is discussed. This concept usually involves the installation of a multifunction nozzle. With the nozzle, the engine thrust can be changed in direction without changing the attitude of the aircraft. Change in the direction of thrust induces a significant change in the aerodynamic forces on the aircraft. Therefore, this device can be used for lift-augmenting as well as stability and control purposes. When the thrust is deflected in the longitudinal direction, the lift force and the pitching stability can be manipulated, while the yawing stability can be controlled by directing the thrust in the lateral direction.

  11. Learning Activities: Students and Recycling. [and] Automobile Aerodynamics.

    ERIC Educational Resources Information Center

    McLaughlin, Charles H., Jr.; Schieber, Rich

    1994-01-01

    The first learning activity is intended to heighten students' awareness of the need for recycling, reuse, and reduction of materials; the second explores the aerodynamics of automobiles. Both include context, concept, objectives, procedure, and materials needed. (SK)

  12. Functional Activation in the Ventral Object Processing Pathway during the First Year

    PubMed Central

    Wilcox, Teresa; Biondi, Marisa

    2016-01-01

    Infants' capacity to represent objects in visual working memory changes substantially during the first year of life. There is a growing body of research focused on identifying neural mechanisms that support this emerging capacity, and the extent to which visual object processing elicits different patterns of cortical activation in the infant as compared to the adult. Recent studies have identified areas in temporal and occipital cortex that mediate infants' developing capacity to track objects on the basis of their featural properties. The current research (Experiments 1 and 2) assessed patterns of activation in posterior temporal cortex and occipital cortex using fNIRS in infants 3–13 months of age as they viewed occlusion events. In the occlusion events, either the same object or featurally distinct objects emerged to each side of a screen. The outcome of these studies, combined, revealed that in infants 3–6 months, posterior temporal cortex was activated to all events, regardless of the featural properties of the objects and whether the event involved one object or two (featurally distinct) objects. Infants 7–8 infants months showed a waning posterior temporal response and by 10–13 months this response was negligible. Additional analysis showed that the age groups did not differ in their visual attention to the events and that changes in HbO were better explained by age in days than head circumference. In contrast to posterior temporal cortex, robust activation was obtained in occipital cortex across all ages tested. One interpretation of these results is that they reflect pruning of the visual object-processing network during the first year. The functional contribution of occipital and posterior temporal cortex, along with higher-level temporal areas, to infants' capacity to keep track of distinct entities in visual working memory is discussed. PMID:26778979

  13. Modeling of aircraft unsteady aerodynamic characteristics. Part 1: Postulated models

    NASA Technical Reports Server (NTRS)

    Klein, Vladislav; Noderer, Keith D.

    1994-01-01

    A short theoretical study of aircraft aerodynamic model equations with unsteady effects is presented. The aerodynamic forces and moments are expressed in terms of indicial functions or internal state variables. The first representation leads to aircraft integro-differential equations of motion; the second preserves the state-space form of the model equations. The formulations of unsteady aerodynamics is applied in two examples. The first example deals with a one-degree-of-freedom harmonic motion about one of the aircraft body axes. In the second example, the equations for longitudinal short-period motion are developed. In these examples, only linear aerodynamic terms are considered. The indicial functions are postulated as simple exponentials and the internal state variables are governed by linear, time-invariant, first-order differential equations. It is shown that both approaches to the modeling of unsteady aerodynamics lead to identical models.

  14. Method for Determining the Weight of Functional Objectives on Manufacturing System

    PubMed Central

    Zhang, Qingshan; Xu, Wei; Zhang, Jiekun

    2014-01-01

    We propose a three-dimensional integrated weight determination to solve manufacturing system functional objectives, where consumers are weighted by triangular fuzzy numbers to determine the enterprises. The weights, subjective parts are determined by the expert scoring method, the objective parts are determined by the entropy method with the competitive advantage of determining. Based on the integration of three methods and comprehensive weight, we provide some suggestions for the manufacturing system. This paper provides the numerical example analysis to illustrate the feasibility of this method. PMID:25243203

  15. Time Domain Identification of an Optimal Control Pilot Model with Emphasis on the Objective Function

    NASA Technical Reports Server (NTRS)

    Schmidt, D. K.

    1982-01-01

    A method for the identification of the pilot's control compensation using time domain techniques is proposed. From this information we hope to infer a quadratic cost function, supported by the data, that represents a reasonable expression for the pilot's control objective in the task being performed, or an inferred piloting strategy. The objectives for this method are: (1) obtain a better understanding of the fundamental piloting techniques in complex tasks, such as landing approach; (2) the development of a metric measurable in simulations and flight test that correlate with subjective pilot opinion; and (3) to further validate pilot models and pilot vehicle analysis methods.

  16. Predicting objective function weights from patient anatomy in prostate IMRT treatment planning

    SciTech Connect

    Lee, Taewoo Hammad, Muhannad; Chan, Timothy C. Y.; Craig, Tim; Sharpe, Michael B.

    2013-12-15

    Purpose: Intensity-modulated radiation therapy (IMRT) treatment planning typically combines multiple criteria into a single objective function by taking a weighted sum. The authors propose a statistical model that predicts objective function weights from patient anatomy for prostate IMRT treatment planning. This study provides a proof of concept for geometry-driven weight determination. Methods: A previously developed inverse optimization method (IOM) was used to generate optimal objective function weights for 24 patients using their historical treatment plans (i.e., dose distributions). These IOM weights were around 1% for each of the femoral heads, while bladder and rectum weights varied greatly between patients. A regression model was developed to predict a patient's rectum weight using the ratio of the overlap volume of the rectum and bladder with the planning target volume at a 1 cm expansion as the independent variable. The femoral head weights were fixed to 1% each and the bladder weight was calculated as one minus the rectum and femoral head weights. The model was validated using leave-one-out cross validation. Objective values and dose distributions generated through inverse planning using the predicted weights were compared to those generated using the original IOM weights, as well as an average of the IOM weights across all patients. Results: The IOM weight vectors were on average six times closer to the predicted weight vectors than to the average weight vector, usingl{sub 2} distance. Likewise, the bladder and rectum objective values achieved by the predicted weights were more similar to the objective values achieved by the IOM weights. The difference in objective value performance between the predicted and average weights was statistically significant according to a one-sided sign test. For all patients, the difference in rectum V54.3 Gy, rectum V70.0 Gy, bladder V54.3 Gy, and bladder V70.0 Gy values between the dose distributions generated by the

  17. Computer graphics in aerodynamic analysis

    NASA Technical Reports Server (NTRS)

    Cozzolongo, J. V.

    1984-01-01

    The use of computer graphics and its application to aerodynamic analyses on a routine basis is outlined. The mathematical modelling of the aircraft geometries and the shading technique implemented are discussed. Examples of computer graphics used to display aerodynamic flow field data and aircraft geometries are shown. A future need in computer graphics for aerodynamic analyses is addressed.

  18. Bat flight: aerodynamics, kinematics and flight morphology.

    PubMed

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. PMID:25740899

  19. Influence of objective function selection on modeling high and low flows in a changing climate

    NASA Astrophysics Data System (ADS)

    Vaze, J.; Petheram, C.; Chiew, F. H.; Teng, J.; Wang, B.; Post, D. A.

    2012-12-01

    This study evaluates the ability of commonly used hydrological models at simulating streamflow under variable climate conditions for different streamflow characteristics. The models are calibrated using three objective functions that weight high and low flow characteristics differently. The models are calibrated using data from ten unregulated catchments in southeast Australia. The results show that when the GR4J model is calibrated against low flows, it performs better in simulating low flows over an independent period compared to the simulation when using a high-flow objective function but this improvement in simulating low flows comes at the cost of poor simulations of high flows. The simulation results for the Sacramento model are different to GR4J and show that the Sacramento model calibrated specifically against low flows does not necessarily perform better in simulating low flows for an independent period not used in model calibration. The results for the two models also show that a model calibrated specifically against low flows does not necessarily perform better in simulating the bias of the lower 30% of fdc for an independent period not used in model calibration. The simulation results for both of the models indicate that model parameters calibrated using an objective function which gives more weight to high and medium flows are suitable for simulating streamflow for an independent period with reasonably high daily NSE values. The results also show that objective functions which puts more weight on low flows or similar weight to all flows is not suitable for simulating streamflow for an independent period if the metric of interest is daily NSE. The simulation-bias results indicate that there is no clear under or overestimation of flows when model parameters calibrated against wet or dry periods are used to simulate streamflow for an independent dry or wet period. The overall results from this study indicate that there is no single objective function that

  20. Unsteady Aerodynamics - Subsonic Compressible Inviscid Case

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1999-01-01

    This paper presents a new analytical treatment of Unsteady Aerodynamics - the linear theory covering the subsonic compressible (inviscid) case - drawing on some recent work in Operator Theory and Functional Analysis. The specific new results are: (a) An existence and uniqueness proof for the Laplace transform version of the Possio integral equation as well as a new closed form solution approximation thereof. (b) A new representation for the time-domain solution of the subsonic compressible aerodynamic equations emphasizing in particular the role of the initial conditions.

  1. A functional investigation of RAN letters, digits, and objects: how similar are they?

    PubMed

    Cummine, Jacqueline; Szepesvari, Eszter; Chouinard, Brea; Hanif, Wahab; Georgiou, George K

    2014-12-15

    Although rapid automatized naming (RAN) of letters, digits, and objects are popular tasks and have been used interchangeably to predict academic performance, it remains unknown if they tap into the same neural regions. Thus, the purpose of this study was to examine the neural overlap across different RAN tasks. Fifteen university students were assessed on RAN digits, letters, and objects using functional magnetic resonance imaging (fMRI). Results showed a common neural pattern that included regions related to motor planning (e.g., cerebellum), semantic access (middle temporal gyrus), articulation (supplementary motor association, motor/pre-motor, anterior cingulate cortex), and grapheme-phoneme mapping (ventral supramarginal gyrus). However, RAN digits and letters showed many unique regions of activation over and above RAN objects particularly in semantic and articulatory regions, including precuneus, bilateral supramarginal gyrus, nucleus accumbens and thalamus. The only region unique to RAN objects included bilateral fusiform, a region commonly implicated in object processing. Overall, our results provide the first neural evidence for a stronger relationship between RAN letters and digits than when either task is compared to RAN objects. PMID:25172183

  2. Prediction of Aerodynamic Coefficients using Neural Networks for Sparse Data

    NASA Technical Reports Server (NTRS)

    Rajkumar, T.; Bardina, Jorge; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Basic aerodynamic coefficients are modeled as functions of angles of attack and sideslip with vehicle lateral symmetry and compressibility effects. Most of the aerodynamic parameters can be well-fitted using polynomial functions. In this paper a fast, reliable way of predicting aerodynamic coefficients is produced using a neural network. The training data for the neural network is derived from wind tunnel test and numerical simulations. The coefficients of lift, drag, pitching moment are expressed as a function of alpha (angle of attack) and Mach number. The results produced from preliminary neural network analysis are very good.

  3. Summary analysis of the Gemini entry aerodynamics

    NASA Technical Reports Server (NTRS)

    Whitnah, A. M.; Howes, D. B.

    1972-01-01

    The aerodynamic data that were derived in 1967 from the analysis of flight-generated data for the Gemini entry module are presented. These data represent the aerodynamic characteristics exhibited by the vehicle during the entry portion of Gemini 2, 3, 5, 8, 10, 11, and 12 missions. For the Gemini, 5, 8, 10, 11, and 12 missions, the flight-generated lift-to-drag ratios and corresponding angles of attack are compared with the wind tunnel data. These comparisons show that the flight generated lift-to-drag ratios are consistently lower than were anticipated from the tunnel data. Numerous data uncertainties are cited that provide an insight into the problems that are related to an analysis of flight data developed from instrumentation systems, the primary functions of which are other than the evaluation of flight aerodynamic performance.

  4. Identification of aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Lan, C. Edward; Hu, C. C.

    1992-01-01

    A Fourier analysis method was developed to analyze harmonic forced-oscillation data at high angles of attack as functions of the angle of attack and its time rate of change. The resulting aerodynamic responses at different frequencies are used to build up the aerodynamic models involving time integrals of the indicial type. An efficient numerical method was also developed to evaluate these time integrals for arbitrary motions based on a concept of equivalent harmonic motion. The method was verified by first using results from two-dimensional and three-dimensional linear theories. The developed models for C sub L, C sub D, and C sub M based on high-alpha data for a 70 deg delta wing in harmonic motions showed accurate results in reproducing hysteresis. The aerodynamic models are further verified by comparing with test data using ramp-type motions.

  5. Aerodynamics of Race Cars

    NASA Astrophysics Data System (ADS)

    Katz, Joseph

    2006-01-01

    Race car performance depends on elements such as the engine, tires, suspension, road, aerodynamics, and of course the driver. In recent years, however, vehicle aerodynamics gained increased attention, mainly due to the utilization of the negative lift (downforce) principle, yielding several important performance improvements. This review briefly explains the significance of the aerodynamic downforce and how it improves race car performance. After this short introduction various methods to generate downforce such as inverted wings, diffusers, and vortex generators are discussed. Due to the complex geometry of these vehicles, the aerodynamic interaction between the various body components is significant, resulting in vortex flows and lifting surface shapes unlike traditional airplane wings. Typical design tools such as wind tunnel testing, computational fluid dynamics, and track testing, and their relevance to race car development, are discussed as well. In spite of the tremendous progress of these design tools (due to better instrumentation, communication, and computational power), the fluid dynamic phenomenon is still highly nonlinear, and predicting the effect of a particular modification is not always trouble free. Several examples covering a wide range of vehicle shapes (e.g., from stock cars to open-wheel race cars) are presented to demonstrate this nonlinear nature of the flow field.

  6. Aerodynamics Improve Wind Wheel

    NASA Technical Reports Server (NTRS)

    Ramsey, V. W.

    1982-01-01

    Modifications based on aerodynamic concepts would raise efficiency of wind-wheel electric-power generator. Changes smooth airflow, to increase power output, without increasing size of wheel. Significant improvements in efficiency anticipated without any increase in size or number of moving parts and without departing from simplicity of original design.

  7. Recent Experiments at the Gottingen Aerodynamic Institute

    NASA Technical Reports Server (NTRS)

    Ackeret, J

    1925-01-01

    This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).

  8. Joint influences of aerodynamic flow field and aerodynamic heating of the dome on imaging quality degradation of airborne optical systems.

    PubMed

    Xiao, Haosu; Zuo, Baojun; Tian, Yi; Zhang, Wang; Hao, Chenglong; Liu, Chaofeng; Li, Qi; Li, Fan; Zhang, Li; Fan, Zhigang

    2012-12-20

    We investigated the joint influences exerted by the nonuniform aerodynamic flow field surrounding the optical dome and the aerodynamic heating of the dome on imaging quality degradation of an airborne optical system. The Spalart-Allmaras model provided by FLUENT was used for flow computations. The fourth-order Runge-Kutta algorithm based ray tracing program was used to simulate optical transmission through the aerodynamic flow field and the dome. Four kinds of imaging quality evaluation parameters were presented: wave aberration of the exit pupil, point spread function, encircled energy, and modulation transfer function. The results show that the aero-optical disturbance of the aerodynamic flow field and the aerodynamic heating of the dome significantly affect the imaging quality of an airborne optical system. PMID:23262604

  9. On the use of the OCM's quadratic objective function as a pilot rating metric

    NASA Technical Reports Server (NTRS)

    Schmidt, D. K.

    1981-01-01

    A correlation between the magnitude of the quadratic objective function from an optimal control pilot model and the subjective rating of the vehicle and task provides a valuable tool for handling qualities research and flight control synthesis. An analysis of simulation results for fourteen aircraft configurations flight tested earlier was conducted. A fixed set of pilot model parameters, are found for all cases in modeling the simulated regulation task. The agreement obtained between performance statistics is shown and a strong correlation was obtained between the cost function and rating.

  10. Simulation and fitting of complex reaction network TPR: The key is the objective function

    DOE PAGESBeta

    Savara, Aditya Ashi

    2016-07-07

    In this research, a method has been developed for finding improved fits during simulation and fitting of data from complex reaction network temperature programmed reactions (CRN-TPR). It was found that simulation and fitting of CRN-TPR presents additional challenges relative to simulation and fitting of simpler TPR systems. The method used here can enable checking the plausibility of proposed chemical mechanisms and kinetic models. The most important finding was that when choosing an objective function, use of an objective function that is based on integrated production provides more utility in finding improved fits when compared to an objective function based onmore » the rate of production. The response surface produced by using the integrated production is monotonic, suppresses effects from experimental noise, requires fewer points to capture the response behavior, and can be simulated numerically with smaller errors. For CRN-TPR, there is increased importance (relative to simple reaction network TPR) in resolving of peaks prior to fitting, as well as from weighting of experimental data points. Using an implicit ordinary differential equation solver was found to be inadequate for simulating CRN-TPR. Lastly, the method employed here was capable of attaining improved fits in simulation and fitting of CRN-TPR when starting with a postulated mechanism and physically realistic initial guesses for the kinetic parameters.« less

  11. Aerodynamic heated steam generating apparatus

    SciTech Connect

    Kim, K.

    1986-08-12

    An aerodynamic heated steam generating apparatus is described which consists of: an aerodynamic heat immersion coil steam generator adapted to be located on the leading edge of an airframe of a hypersonic aircraft and being responsive to aerodynamic heating of water by a compression shock airstream to produce steam pressure; an expansion shock air-cooled condensor adapted to be located in the airframe rearward of and operatively coupled to the aerodynamic heat immersion coil steam generator to receive and condense the steam pressure; and an aerodynamic heated steam injector manifold adapted to distribute heated steam into the airstream flowing through an exterior generating channel of an air-breathing, ducted power plant.

  12. Objectively Measured Physical Activity is Related to Cognitive Function in Older Adults

    PubMed Central

    Kerr, Jacqueline; Marshall, Simon J.; Patterson, Ruth E.; Marinac, Catherine R.; Natarajan, Loki; Rosenberg, Dori; Wasilenko, Kari; Crist, Katie

    2013-01-01

    Background/Objectives To explore the relationship between cognitive functioning and the time spent at different intensities of physical activity (PA) in free-living older adults. Design, Setting Cross sectional analyses of participants enrolled in a randomized controlled trial set in continuing care retirement communities. Participants 215 older adults residing in 7 continuing care retirement communities in San Diego County: average age 83 years, 70% female and 35% with graduate level education. Measurements PA was measured objectively by hip worn accelerometers with data aggregated to the minute level. Three cut points were used to assess low-light, high-light, and moderate-to-vigorous intensity PA (MVPA). Trail Making Tests A and B were completed and time for each test (sec) and test B-minus- A time (sec) were used as measures of cognitive functioning. Variables were log transformed and entered into linear regression models adjusting for demographic factors (age, education, gender) and other PA intensity variables. Results Low-light PA was not related to any Trails test score. High-light PA was significantly related to Trails A, B and B-minus-A; but only in unadjusted models. MVPA was related to Trails B and B-minus-A after adjusting for demographic variables. Conclusion These data suggest there may be a dose response between PA intensity and cognitive functioning in older adults. The stronger findings supporting a relationship between MVPA and cognitive functioning are consistent with previous observational and intervention studies. PMID:24219194

  13. How Tactile and Function Information Affect Young Children's Ability to Understand the Nature of Food-Appearing, Deceptive Objects

    ERIC Educational Resources Information Center

    Krause, Christina Miles

    2008-01-01

    Preschool children's (N = 64) ability to use tactile information and function cues on less-realistic and more-realistic food-appearing, deceptive objects was examined before and after training on the function of deceptive objects. They also responded to appearance and reality questions about deceptive objects. Half of the children (F-S:…

  14. Multilevel Green's function interpolation method for scattering from composite metallic and dielectric objects.

    PubMed

    Shi, Yan; Wang, Hao Gang; Li, Long; Chan, Chi Hou

    2008-10-01

    A multilevel Green's function interpolation method based on two kinds of multilevel partitioning schemes--the quasi-2D and the hybrid partitioning scheme--is proposed for analyzing electromagnetic scattering from objects comprising both conducting and dielectric parts. The problem is formulated using the surface integral equation for homogeneous dielectric and conducting bodies. A quasi-2D multilevel partitioning scheme is devised to improve the efficiency of the Green's function interpolation. In contrast to previous multilevel partitioning schemes, noncubic groups are introduced to discretize the whole EM structure in this quasi-2D multilevel partitioning scheme. Based on the detailed analysis of the dimension of the group in this partitioning scheme, a hybrid quasi-2D/3D multilevel partitioning scheme is proposed to effectively handle objects with fine local structures. Selection criteria for some key parameters relating to the interpolation technique are given. The proposed algorithm is ideal for the solution of problems involving objects such as missiles, microstrip antenna arrays, photonic bandgap structures, etc. Numerical examples are presented to show that CPU time is between O(N) and O(N log N) while the computer memory requirement is O(N). PMID:18830332

  15. Are Children with Autism Spectrum Disorder Initially Attuned to Object Function Rather than Shape for Word Learning?

    ERIC Educational Resources Information Center

    Field, Charlotte; Allen, Melissa L.; Lewis, Charlie

    2016-01-01

    We investigate the function bias--generalising words to objects with the same function--in typically developing (TD) children, children with autism spectrum disorder (ASD) and children with other developmental disorders. Across four trials, a novel object was named and its function was described and demonstrated. Children then selected the other…

  16. Advanced Aerodynamic Control Effectors

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Bauer, Steven X. S.

    1999-01-01

    A 1990 research program that focused on the development of advanced aerodynamic control effectors (AACE) for military aircraft has been reviewed and summarized. Data are presented for advanced planform, flow control, and surface contouring technologies. The data show significant increases in lift, reductions in drag, and increased control power, compared to typical aerodynamic designs. The results presented also highlighted the importance of planform selection in the design of a control effector suite. Planform data showed that dramatic increases in lift (greater than 25%) can be achieved with multiple wings and a sawtooth forebody. Passive porosity and micro drag generator control effector data showed control power levels exceeding that available from typical effectors (moving surfaces). Application of an advanced planform to a tailless concept showed benefits of similar magnitude as those observed in the generic studies.

  17. Steady-State Contrast Response Functions Provide a Sensitive and Objective Index of Amblyopic Deficits

    PubMed Central

    Baker, Daniel H.; Simard, Mathieu; Saint-Amour, Dave; Hess, Robert F.

    2015-01-01

    Purpose. Visual deficits in amblyopia are neural in origin, yet are difficult to characterize with functional magnetic resonance imagery (fMRI). Our aim was to develop an objective electroencephalography (EEG) paradigm that can be used to provide a clinically useful index of amblyopic deficits. Methods. We used steady-state visual evoked potentials (SSVEPs) to measure full contrast response functions in both amblyopic (n = 10, strabismic or mixed amblyopia, mean age: 44 years) and control (n = 5, mean age: 31 years) observers, both with and without a dichoptic mask. Results. At the highest target contrast, the ratio of amplitudes across the weaker and stronger eyes was highly correlated (r = 0.76) with the acuity ratio between the eyes. We also found that the contrast response function in the amblyopic eye had both a greatly reduced amplitude and a shallower slope, but that surprisingly dichoptic masking was weaker than in controls. The results were compared with the predictions of a computational model of amblyopia and suggest a modification to the model whereby excitatory (but not suppressive) signals are attenuated in the amblyopic eye. Conclusions. We suggest that SSVEPs offer a sensitive and objective measure of the ocular imbalance in amblyopia and could be used to assess the efficacy of amblyopia therapies currently under development. PMID:25634977

  18. Objective Function and Learning Algorithm for the General Node Fault Situation.

    PubMed

    Xiao, Yi; Feng, Rui-Bin; Leung, Chi-Sing; Sum, John

    2016-04-01

    Fault tolerance is one interesting property of artificial neural networks. However, the existing fault models are able to describe limited node fault situations only, such as stuck-at-zero and stuck-at-one. There is no general model that is able to describe a large class of node fault situations. This paper studies the performance of faulty radial basis function (RBF) networks for the general node fault situation. We first propose a general node fault model that is able to describe a large class of node fault situations, such as stuck-at-zero, stuck-at-one, and the stuck-at level being with arbitrary distribution. Afterward, we derive an expression to describe the performance of faulty RBF networks. An objective function is then identified from the formula. With the objective function, a training algorithm for the general node situation is developed. Finally, a mean prediction error (MPE) formula that is able to estimate the test set error of faulty networks is derived. The application of the MPE formula in the selection of basis width is elucidated. Simulation experiments are then performed to demonstrate the effectiveness of the proposed method. PMID:26990391

  19. An objective measure of physical function of elderly outpatients. The Physical Performance Test.

    PubMed

    Reuben, D B; Siu, A L

    1990-10-01

    Direct observation of physical function has the advantage of providing an objective, quantifiable measure of functional capabilities. We have developed the Physical Performance Test (PPT), which assesses multiple domains of physical function using observed performance of tasks that simulate activities of daily living of various degrees of difficulty. Two versions are presented: a nine-item scale that includes writing a sentence, simulated eating, turning 360 degrees, putting on and removing a jacket, lifting a book and putting it on a shelf, picking up a penny from the floor, a 50-foot walk test, and climbing stairs (scored as two items); and a seven-item scale that does not include stairs. The PPT can be completed in less than 10 minutes and requires only a few simple props. We then tested the validity of PPT using 183 subjects (mean age, 79 years) in six settings including four clinical practices (one of Parkinson's disease patients), a board-and-care home, and a senior citizens' apartment. The PPT was reliable (Cronbach's alpha = 0.87 and 0.79, interrater reliability = 0.99 and 0.93 for the nine-item and seven-item tests, respectively) and demonstrated concurrent validity with self-reported measures of physical function. Scores on the PPT for both scales were highly correlated (.50 to .80) with modified Rosow-Breslau, Instrumental and Basic Activities of Daily Living scales, and Tinetti gait score. Scores on the PPT were more moderately correlated with self-reported health status, cognitive status, and mental health (.24 to .47), and negatively with age (-.24 and -.18). Thus, the PPT also demonstrated construct validity. The PPT is a promising objective measurement of physical function, but its clinical and research value for screening, monitoring, and prediction will have to be determined. PMID:2229864

  20. Sedentary behavior and physical function: Objective Evidence from the Osteoarthritis Initiative

    PubMed Central

    Lee, Jungwha; Chang, Rowland W.; Ehrlich-Jones, Linda; Kwoh, C. Kent; Nevitt, Michael; Semanik, Pamela A.; Sharma, Leena; Sohn, Min-Woong; Song, Jing; Dunlop, Dorothy D.

    2014-01-01

    Objective Investigate the relationship between sedentary behavior and physical function in adults with knee osteoarthritis (OA), controlling for moderate-vigorous physical activity () levels. Methods Sedentary behavior was objectively measured by accelerometer on 1,168 participants in the Osteoarthritis Initiative aged 49–83 years with radiographic knee OA at the 48 month clinic visit. Physical function was assessed using 20-meter walk and chair stand testing. Sedentary behavior was identified by accelerometer activity counts/minute <100. The cross-sectional association between sedentary quartiles and physical function was examined by multiple linear regression adjusting for demographic factors (age, sex, race/ethnicity, education level), health factors (comorbidity, body mass index, knee pain, knee OA severity, presence of knee symptoms) and average daily MVPA minutes. Results Adults with knee OA spent 2/3 their daily time in sedentary behavior. The average gait speed among the most sedentary quartile was 3.88 feet/second, which was significantly slower than the speed of the less sedentary groups (4.23, 4.33, 4.33 feet/second, respectively). The average chair stand rate among the most sedentary group was significantly lower (25.9 stands/minute) than the rates of the less sedentary behavior groups (28.9, 29.1, 31.1 stands/minute, respectively). These trends remained significant in multivariable analyses adjusted for demographic factors, health factors and average daily MVPA minutes. Conclusion Being less sedentary was related to better physical function in adults with knee OA independent of MVPA time. These findings support guidelines to encourage adults with knee OA to decrease time spent in sedentary behavior in order to improve physical function. PMID:25155652

  1. Aerodynamic characteristics of aerofoils I

    NASA Technical Reports Server (NTRS)

    1921-01-01

    The object of this report is to bring together the investigations of the various aerodynamic laboratories in this country and Europe upon the subject of aerofoils suitable for use as lifting or control surfaces on aircraft. The data have been so arranged as to be of most use to designing engineers and for the purposes of general reference. The absolute system of coefficients has been used, since it is thought by the National Advisory Committee for Aeronautics that this system is the one most suited for international use, and yet is one for which a desired transformation can be easily made. For this purpose a set of transformation constants is included in this report.

  2. Aerodynamics: The Wright Way

    NASA Technical Reports Server (NTRS)

    Cole, Jennifer Hansen

    2010-01-01

    This slide presentation reviews some of the basic principles of aerodynamics. Included in the presentation are: a few demonstrations of the principles, an explanation of the concepts of lift, drag, thrust and weight, a description of Bernoulli's principle, the concept of the airfoil (i.e., the shape of the wing) and how that effects lift, and the method of controlling an aircraft by manipulating the four forces using control surfaces.

  3. The Importance of Behavioral Thresholds and Objective Functions in Contaminant Transport Uncertainty Analysis

    NASA Astrophysics Data System (ADS)

    Sykes, J. F.; Kang, M.; Thomson, N. R.

    2007-12-01

    The TCE release from The Lockformer Company in Lisle Illinois resulted in a plume in a confined aquifer that is more than 4 km long and impacted more than 300 residential wells. Many of the wells are on the fringe of the plume and have concentrations that did not exceed 5 ppb. The settlement for the Chapter 11 bankruptcy protection of Lockformer involved the establishment of a trust fund that compensates individuals with cancers with payments being based on cancer type, estimated TCE concentration in the well and the duration of exposure to TCE. The estimation of early arrival times and hence low likelihood events is critical in the determination of the eligibility of an individual for compensation. Thus, an emphasis must be placed on the accuracy of the leading tail region in the likelihood distribution of possible arrival times at a well. The estimation of TCE arrival time, using a three-dimensional analytical solution, involved parameter estimation and uncertainty analysis. Parameters in the model included TCE source parameters, groundwater velocities, dispersivities and the TCE decay coefficient for both the confining layer and the bedrock aquifer. Numerous objective functions, which include the well-known L2-estimator, robust estimators (L1-estimators and M-estimators), penalty functions, and dead zones, were incorporated in the parameter estimation process to treat insufficiencies in both the model and observational data due to errors, biases, and limitations. The concept of equifinality was adopted and multiple maximum likelihood parameter sets were accepted if pre-defined physical criteria were met. The criteria ensured that a valid solution predicted TCE concentrations for all TCE impacted areas. Monte Carlo samples are found to be inadequate for uncertainty analysis of this case study due to its inability to find parameter sets that meet the predefined physical criteria. Successful results are achieved using a Dynamically-Dimensioned Search sampling

  4. Identification of aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Chin, Suei; Lan, C. Edward

    1990-01-01

    Due to the requirement of increased performance and maneuverability, the flight envelope of a modern fighter is frequently extended to the high angle-of-attack regime. Vehicles maneuvering in this regime are subjected to nonlinear aerodynamic loads. The nonlinearities are due mainly to three-dimensional separated flow and concentrated vortex flow that occur at large angles of attack. Accurate prediction of these nonlinear airloads is of great importance in the analysis of a vehicle's flight motion and in the design of its flight control system. A satisfactory evaluation of the performance envelope of the aircraft may require a large number of coupled computations, one for each change in initial conditions. To avoid the disadvantage of solving the coupled flow-field equations and aircraft's motion equations, an alternate approach is to use a mathematical modeling to describe the steady and unsteady aerodynamics for the aircraft equations of motion. Aerodynamic forces and moments acting on a rapidly maneuvering aircraft are, in general, nonlinear functions of motion variables, their time rate of change, and the history of maneuvering. A numerical method was developed to analyze the nonlinear and time-dependent aerodynamic response to establish the generalized indicial function in terms of motion variables and their time rates of change.

  5. Rarefield-Flow Shuttle Aerodynamics Flight Model

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Larman, Kevin T.; Moats, Christina D.

    1994-01-01

    A model of the Shuttle Orbiter rarefied-flow aerodynamic force coefficients has been derived from the ratio of flight acceleration measurements. The in-situ, low-frequency (less than 1Hz), low-level (approximately 1 x 10(exp -6) g) acceleration measurements are made during atmospheric re-entry. The experiment equipment designed and used for this task is the High Resolution Accelerometer Package (HiRAP), one of the sensor packages in the Orbiter Experiments Program. To date, 12 HiRAP re-entry mission data sets spanning a period of about 10 years have been processed. The HiRAP-derived aerodynamics model is described in detail. The model includes normal and axial hypersonic continuum coefficient equations as function of angle of attack, body-flap deflection, and elevon deflection. Normal and axial free molecule flow coefficient equations as a function of angle of attack are also presented, along with flight-derived rarefied-flow transition bridging formulae. Comparisons are made between the aerodynamics model, data from the latest Orbiter Operational Aerodynamic Design Data Book, applicable computer simulations, and wind-tunnel data.

  6. A Generic Nonlinear Aerodynamic Model for Aircraft

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2014-01-01

    A generic model of the aerodynamic coefficients was developed using wind tunnel databases for eight different aircraft and multivariate orthogonal functions. For each database and each coefficient, models were determined using polynomials expanded about the state and control variables, and an othgonalization procedure. A predicted squared-error criterion was used to automatically select the model terms. Modeling terms picked in at least half of the analyses, which totalled 45 terms, were retained to form the generic nonlinear aerodynamic (GNA) model. Least squares was then used to estimate the model parameters and associated uncertainty that best fit the GNA model to each database. Nonlinear flight simulations were used to demonstrate that the GNA model produces accurate trim solutions, local behavior (modal frequencies and damping ratios), and global dynamic behavior (91% accurate state histories and 80% accurate aerodynamic coefficient histories) under large-amplitude excitation. This compact aerodynamics model can be used to decrease on-board memory storage requirements, quickly change conceptual aircraft models, provide smooth analytical functions for control and optimization applications, and facilitate real-time parametric system identification.

  7. Improvements in the sensibility of MSA-GA tool using COFFEE objective function

    NASA Astrophysics Data System (ADS)

    Amorim, A. R.; Zafalon, G. F. D.; Neves, L. A.; Pinto, A. R.; Valêncio, C. R.; Machado, J. M.

    2015-01-01

    The sequence alignment is one of the most important tasks in Bioinformatics, playing an important role in the sequences analysis. There are many strategies to perform sequence alignment, since those use deterministic algorithms, as dynamic programming, until those ones, which use heuristic algorithms, as Progressive, Ant Colony (ACO), Genetic Algorithms (GA), Simulated Annealing (SA), among others. In this work, we have implemented the objective function COFFEE in the MSA-GA tool, in substitution of Weighted Sum-of-Pairs (WSP), to improve the final results. In the tests, we were able to verify the approach using COFFEE function achieved better results in 81% of the lower similarity alignments when compared with WSP approach. Moreover, even in the tests with more similar sets, the approach using COFFEE was better in 43% of the times.

  8. GENASIS   Basics: Object-oriented utilitarian functionality for large-scale physics simulations

    NASA Astrophysics Data System (ADS)

    Cardall, Christian Y.; Budiardja, Reuben D.

    2015-11-01

    Aside from numerical algorithms and problem setup, large-scale physics simulations on distributed-memory supercomputers require more basic utilitarian functionality, such as physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. Here we describe and make available Fortran 2003 classes furnishing extensible object-oriented implementations of this sort of rudimentary functionality, along with individual 'unit test' programs and larger example problems demonstrating their use. These classes compose the Basics division of our developing astrophysics simulation code GENASIS  (General Astrophysical Simulation System), but their fundamental nature makes them useful for physics simulations in many fields.

  9. GenASiS Basics: Object-oriented utilitarian functionality for large-scale physics simulations

    SciTech Connect

    Cardall, Christian Y.; Budiardja, Reuben D.

    2015-06-11

    Aside from numerical algorithms and problem setup, large-scale physics simulations on distributed-memory supercomputers require more basic utilitarian functionality, such as physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. Here we describe and make available Fortran 2003 classes furnishing extensible object-oriented implementations of this sort of rudimentary functionality, along with individual `unit test' programs and larger example problems demonstrating their use. Lastly, these classes compose the Basics division of our developing astrophysics simulation code GenASiS (General Astrophysical Simulation System), but their fundamental nature makes them useful for physics simulations in many fields.

  10. GenASiS Basics: Object-oriented utilitarian functionality for large-scale physics simulations

    DOE PAGESBeta

    Cardall, Christian Y.; Budiardja, Reuben D.

    2015-06-11

    Aside from numerical algorithms and problem setup, large-scale physics simulations on distributed-memory supercomputers require more basic utilitarian functionality, such as physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. Here we describe and make available Fortran 2003 classes furnishing extensible object-oriented implementations of this sort of rudimentary functionality, along with individual `unit test' programs and larger example problems demonstrating their use. Lastly, these classes compose the Basics division of our developing astrophysics simulation code GenASiS (General Astrophysical Simulation System), but their fundamental nature makes themmore » useful for physics simulations in many fields.« less

  11. Executive Functions in Older Adults With Autism Spectrum Disorder: Objective Performance and Subjective Complaints.

    PubMed

    Davids, Roeliena C D; Groen, Yvonne; Berg, Ina J; Tucha, Oliver M; van Balkom, Ingrid D C

    2016-09-01

    Although deficits in Executive Functioning (EF) are reported frequently in young individuals with Autism Spectrum Disorders (ASD), they remain relatively unexplored later in life (>50 years). We studied objective performance on EF measures (Tower of London, Zoo map, phonetic/semantic fluency) as well as subjective complaints (self- and proxy reported BRIEF) in 36 ASD and 36 typically developed individuals (n = 72). High functioning older adults with ASD reported EF-impairments in metacognition, but did not deviate in EF task performance, except for a longer execution time of the Tower of London. The need for additional time to complete daily tasks may contribute to impairments in daily life and may be correlated to a higher level of experienced EF-difficulties in ASD. PMID:27278313

  12. An objective approach to marginal benefit functions for environmental flows: an example for fluvial systems

    NASA Astrophysics Data System (ADS)

    Perona, P.; Burlando, P.

    2009-12-01

    Environmental flows can result from the economical competition for water allocation between traditional and non-traditional water uses. This requires the definition of convenient benefit functions (bf) associated with the use of the resource. Since the use of water by the riparian ecosystem is an intangible good, common ways based for instance on the “willingness to pay” have the dramatic weakness of not being objective with regard to the environmental rights. That is, water withdrawal from a given stream environment would depend on the importance and, in turn, on the economical value that people assign to this environment. In this work we discuss a possible objective criterion to establish benefit functions for the environmental uses of the water resource. Our approach is based on studying the optimal water allocation between the users as resulting from marginal economic analysis. That is, we show that the parameters of the marginal demand curve for the riparian ecosystem are intrinsically defined by knowing: (a) the ecological status of the riverine system in pristine conditions, and (b) the marginal benefit function of the potential competitor (e.g., exploitation activity). We solve analytically the water allocation problem for the simple case of water withdrawal from a fluvial system. We show the link between the parameters of the marginal benefit functions and the minimal environmental flow arising from classic engineering analysis, as well as their ecological meaning. This approach allows to restore a more natural variability of the streamflow regime in impounded reaches, to the cost of a profit reduction for the resource exploitation. However, on the long term, the overall idea is that the benefit for having preserved more natural environmental flow conditions since exploitation began would balance the future cost for potential restoration of the riverine corridor and the missing revenues.

  13. Classification of functional bowel disorders by objective physiological criteria based on endoluminal image analysis.

    PubMed

    Malagelada, Carolina; Drozdzal, Michal; Seguí, Santi; Mendez, Sara; Vitrià, Jordi; Radeva, Petia; Santos, Javier; Accarino, Anna; Malagelada, Juan-R; Azpiroz, Fernando

    2015-09-15

    We have previously developed an original method to evaluate small bowel motor function based on computer vision analysis of endoluminal images obtained by capsule endoscopy. Our aim was to demonstrate intestinal motor abnormalities in patients with functional bowel disorders by endoluminal vision analysis. Patients with functional bowel disorders (n = 205) and healthy subjects (n = 136) ingested the endoscopic capsule (Pillcam-SB2, Given-Imaging) after overnight fast and 45 min after gastric exit of the capsule a liquid meal (300 ml, 1 kcal/ml) was administered. Endoluminal image analysis was performed by computer vision and machine learning techniques to define the normal range and to identify clusters of abnormal function. After training the algorithm, we used 196 patients and 48 healthy subjects, completely naive, as test set. In the test set, 51 patients (26%) were detected outside the normal range (P < 0.001 vs. 3 healthy subjects) and clustered into hypo- and hyperdynamic subgroups compared with healthy subjects. Patients with hypodynamic behavior (n = 38) exhibited less luminal closure sequences (41 ± 2% of the recording time vs. 61 ± 2%; P < 0.001) and more static sequences (38 ± 3 vs. 20 ± 2%; P < 0.001); in contrast, patients with hyperdynamic behavior (n = 13) had an increased proportion of luminal closure sequences (73 ± 4 vs. 61 ± 2%; P = 0.029) and more high-motion sequences (3 ± 1 vs. 0.5 ± 0.1%; P < 0.001). Applying an original methodology, we have developed a novel classification of functional gut disorders based on objective, physiological criteria of small bowel function. PMID:26251472

  14. Genetic Algorithm Based Objective Functions Comparative Study for Damage Detection and Localization in Beam Structures

    NASA Astrophysics Data System (ADS)

    Khatir, S.; Belaidi, I.; Serra, R.; Benaissa, B.; Ait Saada, A.

    2015-07-01

    The detection techniques based on non-destructive testing (NDT) defects are preferable because of their low cost and operational aspects related to the use of the analyzed structure. In this study, we used the genetic algorithm (GA) for detecting and locating damage. The finite element was used for diagnostic beams. Different structures considered may incur damage to be modelled by a loss of rigidity supposed to represent a defect in the structure element. Identification of damage is formulated as an optimization problem using three objective functions (change of natural frequencies, Modal Assurance Criterion MAC and MAC natural frequency). The results show that the best objective function is based on the natural frequency and MAC while the method of the genetic algorithm present its efficiencies in indicating and quantifying multiple damage with great accuracy. Three defects have been created to enhance damage depending on the elements 2, 5 and 8 with a percentage allocation of 50% in the beam structure which has been discretized into 10 elements. Finally the defect with noise was introduced to test the stability of the method against uncertainty.

  15. Preverbal Functional Communication and the Role of Object Play in Children with Cerebral Palsy.

    ERIC Educational Resources Information Center

    Olswang, Lesley B.; Pinder, Gay Lloyd

    1995-01-01

    Object play and communication development were studied with four infants with cerebral palsy, involving time spent with objects, types of object play, and object selection. As coordinated looking between object and adult emerged, children demonstrated increased interest in objects and sophistication in their play behaviors. (SW)

  16. A Rapid Aerodynamic Design Procedure Based on Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan

    2001-01-01

    An aerodynamic design procedure that uses neural networks to model the functional behavior of the objective function in design space has been developed. This method incorporates several improvements to an earlier method that employed a strategy called parameter-based partitioning of the design space in order to reduce the computational costs associated with design optimization. As with the earlier method, the current method uses a sequence of response surfaces to traverse the design space in search of the optimal solution. The new method yields significant reductions in computational costs by using composite response surfaces with better generalization capabilities and by exploiting synergies between the optimization method and the simulation codes used to generate the training data. These reductions in design optimization costs are demonstrated for a turbine airfoil design study where a generic shape is evolved into an optimal airfoil.

  17. Aerodynamics of a Cryogenic Semi-Tanker

    NASA Astrophysics Data System (ADS)

    Ortega, Jason; Salari, Kambiz

    2009-11-01

    The design of a modern cryogenic semi-tanker is based primarily upon functionality with little consideration given to aerodynamic drag. As a result, these tankers have maintained the appearance of a wheeled cylinder for several decades. To reduce the fuel usage of these vehicles, this study investigates their aerodynamics. A detailed understanding of the flow field about the vehicle and its influence on aerodynamic drag is obtained by performing Reynolds-Averaged Navier-Stokes simulations of a full-scale tractor and cryogenic tanker-trailer operating at highway speed within a crosswind. The tanker-trailer has a length to diameter ratio of 6.3. The Reynolds number, based upon the tanker diameter, is 4.0x10^6, while the effective vehicle yaw angle is 6.1 . The flow field about the vehicle is characterized by large flow separation regions at the tanker underbody and base. In addition, the relatively large gap between the tractor and the tanker-trailer allows the free-stream flow to be entrained into the tractor-tanker gap. By mitigating these drag-producing phenomena through the use of simple geometry modifications, it may be possible to reduce the aerodynamic drag of cryogenic semi-tankers and, thereby, improve their fuel economy. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. SUBSTELLAR OBJECTS IN NEARBY YOUNG CLUSTERS. VII. THE SUBSTELLAR MASS FUNCTION REVISITED

    SciTech Connect

    Scholz, Alexander; Geers, Vincent; Clark, Paul; Jayawardhana, Ray; Muzic, Koraljka

    2013-10-01

    The abundance of brown dwarfs (BDs) in young clusters is a diagnostic of star formation theory. Here we revisit the issue of determining the substellar initial mass function (IMF) based on a comparison between NGC 1333 and IC348, two clusters in the Perseus star-forming region. We derive their mass distributions for a range of model isochrones, varying distances, extinction laws, and ages with comprehensive assessments of the uncertainties. We find that the choice of isochrone and other parameters have significant effects on the results, thus we caution against comparing IMFs obtained using different approaches. For NGC 1333, we find that the star/BD ratio R is between 1.9 and 2.4 for all plausible scenarios, consistent with our previous work. For IC348, R is found to be between 2.9 and 4.0, suggesting that previous studies have overestimated this value. Thus the star-forming process generates about 2.5-5 substellar objects per 10 stars. The derived star/BD ratios correspond to a slope of the power-law mass function of α = 0.7-1.0 for the 0.03-1.0 M{sub ☉} mass range. The median mass in these clusters—the typical stellar mass—is between 0.13 and 0.30 M{sub ☉}. Assuming that NGC 1333 is at a shorter distance than IC348, we find a significant difference in the cumulative distribution of masses between the two clusters, resulting from an overabundance of very low mass objects in NGC 1333. Gaia astrometry will constrain the cluster distances better and will lead to a more definitive conclusion. Furthermore, the star/BD ratio is somewhat larger in IC348 compared with NGC 1333, although this difference is still within the margins of error. Our results indicate that environments with higher object density may produce a larger fraction of very low mass objects, in line with predictions for BD formation through gravitational fragmentation of filaments falling into a cluster potential.

  19. Using Object Boxes to Teach the Form, Function, and Vocabulary of the Parts of the Human Eye

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Welch, Genne

    2008-01-01

    These science activities for elementary students focus on the external structures and functions of the human eye with hands-on object box activities based on the Montessori theory (1966) of concrete learning through manipulation of objects and focus of attention through touch. Object boxes are sets of items and corresponding cards housed in a box.…

  20. Freight Wing Trailer Aerodynamics

    SciTech Connect

    Graham, Sean; Bigatel, Patrick

    2004-10-17

    Freight Wing Incorporated utilized the opportunity presented by this DOE category one Inventions and Innovations grant to successfully research, develop, test, patent, market, and sell innovative fuel and emissions saving aerodynamic attachments for the trucking industry. A great deal of past scientific research has demonstrated that streamlining box shaped semi-trailers can significantly reduce a truck's fuel consumption. However, significant design challenges have prevented past concepts from meeting industry needs. Market research early in this project revealed the demands of truck fleet operators regarding aerodynamic attachments. Products must not only save fuel, but cannot interfere with the operation of the truck, require significant maintenance, add significant weight, and must be extremely durable. Furthermore, SAE/TMC J1321 tests performed by a respected independent laboratory are necessary for large fleets to even consider purchase. Freight Wing used this information to create a system of three practical aerodynamic attachments for the front, rear and undercarriage of standard semi trailers. SAE/TMC J1321 Type II tests preformed by the Transportation Research Center (TRC) demonstrated a 7% improvement to fuel economy with all three products. If Freight Wing is successful in its continued efforts to gain market penetration, the energy and environmental savings would be considerable. Each truck outfitted saves approximately 1,100 gallons of fuel every 100,000 miles, which prevents over 12 tons of CO2 from entering the atmosphere. If all applicable trailers used the technology, the country could save approximately 1.8 billion gallons of diesel fuel, 18 million tons of emissions and 3.6 billion dollars annually.

  1. Using a multi-agent evidential reasoning network as the objective function for an evolutionary algorithm

    NASA Astrophysics Data System (ADS)

    Woodley, Robert; Lindahl, Eric; Barker, Joseph

    2007-04-01

    A culturally diverse group of people are now participating in military multinational coalition operations (e.g., combined air operations center, training exercises such as Red Flag at Nellis AFB, NATO AWACS), as well as in extreme environments. Human biases and routines, capabilities, and limitations strongly influence overall system performance; whether during operations or simulations using models of humans. Many missions and environments challenge human capabilities (e.g., combat stress, waiting, fatigue from long duty hours or tour of duty). This paper presents a team selection algorithm based on an evolutionary algorithm. The main difference between this and the standard EA is that a new form of objective function is used that incorporates the beliefs and uncertainties of the data. Preliminary results show that this selection algorithm will be very beneficial for very large data sets with multiple constraints and uncertainties. This algorithm will be utilized in a military unit selection tool.

  2. Proposal of Functional-Specialization Multi-Objective Real-Coded Genetic Algorithm: FS-MOGA

    NASA Astrophysics Data System (ADS)

    Hamada, Naoki; Tanaka, Masaharu; Sakuma, Jun; Kobayashi, Shigenobu; Ono, Isao

    This paper presents a Genetic Algorithm (GA) for multi-objective function optimization. To find a precise and widely-distributed set of solutions in difficult multi-objective function optimization problems which have multimodality and curved Pareto-optimal set, a GA would be required conflicting behaviors in the early stage and the last stage of search. That is, in the early stage of search, GA should perform local-Pareto-optima-overcoming search which aims to overcome local Pareto-optima and converge the population to promising areas in the decision variable space. On the other hand, in the last stage of search, GA should perform Pareto-frontier-covering search which aims to spread the population along the Pareto-optimal set. NSGA-II and SPEA2, the most widely used conventional methods, have problems in local-Pareto-optima-overcoming and Pareto-frontier-covering search. In local-Pareto-optima-overcoming search, their selection pressure is too high to maintain the diversity for overcoming local Pareto-optima. In Pareto-frontier-covering search, their abilities of extrapolation-directed sampling are not enough to spread the population and they cannot sample along the Pareto-optimal set properly. To resolve above problems, the proposed method adaptively switches two search strategies, each of which is specialized for local-Pareto-optima-overcoming and Pareto-frontier-covering search, respectively. We examine the effectiveness of the proposed method using two benchmark problems. The experimental results show that our approach outperforms the conventional methods in terms of both local-Pareto-optima-overcoming and Pareto-frontier-covering search.

  3. Objective Measures of Swallowing Function Applied to the Dysphagia Population: A One Year Experience.

    PubMed

    Kendall, Katherine A; Ellerston, Julia; Heller, Amanda; Houtz, Daniel R; Zhang, Chong; Presson, Angela P

    2016-08-01

    Quantitative, reliable measures of swallowing physiology can be made from an modified barium swallowing study. These quantitative measures have not been previously employed to study large dysphagic patient populations. The present retrospective study of 139 consecutive patients with dysphagia seen in a university tertiary voice and swallowing clinic sought to use objective measures of swallowing physiology to (1) quantify the most prevalent deficits seen in the patient population, (2) identify commonly associated diagnoses and describe the most prevalent swallowing deficits, and (3) determine any correlation between objective deficits and Eating Assessment Tool (EAT-10) scores and body mass index. Poor pharyngeal constriction (34.5 %) and airway protection deficits (65.5 %) were the most common swallowing abnormalities. Reflux-related dysphagia (36 %), nonspecific pharyngeal dysphagia (24 %), Parkinson disease (16 %), esophageal abnormality (13 %), and brain insult (10 %) were the most common diagnoses. Poor pharyngeal constriction was significantly associated with an esophageal motility abnormality (p < 0.001) and central neurologic insult. In general, dysphagia symptoms as determined by the EAT-10 did not correlate with swallowing function abnormalities. This preliminary study indicates that reflux disease is common in patients with dysphagia and that associated esophageal abnormalities are common in dysphagic populations and may be associated with specific pharyngeal swallowing abnormalities. However, symptom scores from the EAT-10 did not correspond to swallowing pathophysiology. PMID:27106909

  4. Analysis of grasping strategies and function in hemiparetic patients using an instrumented object.

    PubMed

    Jarrassé, Nathanaël; Kühne, Markus; Roach, Nick; Hussain, Asif; Balasubramanian, Sivakumar; Burdet, Etienne; Roby-Brami, Agnès

    2013-06-01

    This paper validates a novel instrumented object, the iBox, dedicated to the analysis of grasping and manipulation. This instrumented box can be grasped and manipulated, is fitted with an Inertial Measurement Unit (IMU) and can sense the force applied on each side and transmits measured force, acceleration and orientation data wirelessly in real time. The iBox also provides simple access to data for analysing human motor control features such as the coordination between grasping and lifting forces and complex manipulation patterns. A set of grasping and manipulation experiments was conducted with 6 hemiparetic patients and 5 healthy control subjects. Measures made of the forces, kinematics and dynamics are developed, which can be used to analyse grasping and contribute to assessment in patients. Quantitative measurements provided by the iBox reveal numerous characteristics of the grasping strategies and function in patients: variations in the completion time, changes in the force distribution on the object and grasping force levels, difficulties to adjust the level of applied forces to the task and to maintain it, along with movement smoothness decrease and pathological tremor. PMID:24187198

  5. An analytical approach to the problem of inverse optimization with additive objective functions: an application to human prehension

    PubMed Central

    Pesin, Yakov B.; Niu, Xun; Latash, Mark L.

    2010-01-01

    We consider the problem of what is being optimized in human actions with respect to various aspects of human movements and different motor tasks. From the mathematical point of view this problem consists of finding an unknown objective function given the values at which it reaches its minimum. This problem is called the inverse optimization problem. Until now the main approach to this problems has been the cut-and-try method, which consists of introducing an objective function and checking how it reflects the experimental data. Using this approach, different objective functions have been proposed for the same motor action. In the current paper we focus on inverse optimization problems with additive objective functions and linear constraints. Such problems are typical in human movement science. The problem of muscle (or finger) force sharing is an example. For such problems we obtain sufficient conditions for uniqueness and propose a method for determining the objective functions. To illustrate our method we analyze the problem of force sharing among the fingers in a grasping task. We estimate the objective function from the experimental data and show that it can predict the force-sharing pattern for a vast range of external forces and torques applied to the grasped object. The resulting objective function is quadratic with essentially non-zero linear terms. PMID:19902213

  6. Incremental Aerodynamic Coefficient Database for the USA2

    NASA Technical Reports Server (NTRS)

    Richardson, Annie Catherine

    2016-01-01

    In March through May of 2016, a wind tunnel test was conducted by the Aerosciences Branch (EV33) to visually study the unsteady aerodynamic behavior over multiple transition geometries for the Universal Stage Adapter 2 (USA2) in the MSFC Aerodynamic Research Facility's Trisonic Wind Tunnel (TWT). The purpose of the test was to make a qualitative comparison of the transonic flow field in order to provide a recommended minimum transition radius for manufacturing. Additionally, 6 Degree of Freedom force and moment data for each configuration tested was acquired in order to determine the geometric effects on the longitudinal aerodynamic coefficients (Normal Force, Axial Force, and Pitching Moment). In order to make a quantitative comparison of the aerodynamic effects of the USA2 transition geometry, the aerodynamic coefficient data collected during the test was parsed and incorporated into a database for each USA2 configuration tested. An incremental aerodynamic coefficient database was then developed using the generated databases for each USA2 geometry as a function of Mach number and angle of attack. The final USA2 coefficient increments will be applied to the aerodynamic coefficients of the baseline geometry to adjust the Space Launch System (SLS) integrated launch vehicle force and moment database based on the transition geometry of the USA2.

  7. Analysis of RapidArc optimization strategies using objective function values and dose-volume histograms.

    PubMed

    Oliver, Michael; Gagne, Isabelle; Popescu, Carmen; Ansbacher, Will; Beckham, Wayne A

    2010-01-01

    RapidArc is a novel treatment planning and delivery system that has recently been made available for clinical use. Included within the Eclipse treatment planning system are a number of different optimization strategies that can be employed to improve the quality of the final treatment plan. The purpose of this study is to systematically assess three categories of strategies for four phantoms, and then apply proven strategies to clinical head and neck cases. Four phantoms were created within Eclipse with varying shapes and locations for the planning target volumes and organs at risk. A baseline optimization consisting of a single 359.8 degrees arc with collimator at 45 degrees was applied to all phantoms. Three categories of strategies were assessed and compared to the baseline strategy. They include changing the initialization parameters, increasing the total number of control points, and increasing the total optimization time. Optimization log files were extracted from the treatment planning system along with final dose-volume histograms for plan assessment. Treatment plans were also generated for four head and neck patients to determine whether the results for phantom plans can be extended to clinical plans. The strategies that resulted in a significant difference from baseline were: changing the maximum leaf speed prior to optimization ( p < 0.05), increasing the total number of segments by adding an arc ( p < 0.05), and increasing the total optimization time by either continuing the optimization ( p < 0.01) or adding time to the optimization by pausing the optimization ( p < 0.01). The reductions in objective function values correlated with improvements in the dose-volume histogram (DVH). The addition of arcs and pausing strategies were applied to head and neck cancer cases, which demonstrated similar benefits with respect to the final objective function value and DVH. Analysis of the optimization log files is a useful way to intercompare treatment plans that

  8. Aerodynamics of sports balls

    NASA Astrophysics Data System (ADS)

    Mehta, R. D.

    Research data on the aerodynamic behavior of baseballs and cricket and golf balls are summarized. Cricket balls and baseballs are roughly the same size and mass but have different stitch patterns. Both are thrown to follow paths that avoid a batter's swing, paths that can curve if aerodynamic forces on the balls' surfaces are asymmetric. Smoke tracer wind tunnel tests and pressure taps have revealed that the unbalanced side forces are induced by tripping the boundary layer on the seam side and producing turbulence. More particularly, the greater pressures are perpendicular to the seam plane and only appear when the balls travel at velocities high enough so that the roughness length matches the seam heigh. The side forces, once tripped, will increase with spin velocity up to a cut-off point. The enhanced lift coefficient is produced by the Magnus effect. The more complex stitching on a baseball permits greater variations in the flight path curve and, in the case of a knuckleball, the unsteady flow effects. For golf balls, the dimples trip the boundary layer and the high spin rate produces a lift coefficient maximum of 0.5, compared to a baseball's maximum of 0.3. Thus, a golf ball travels far enough for gravitational forces to become important.

  9. Aerodynamics of sports balls

    NASA Technical Reports Server (NTRS)

    Mehta, R. D.

    1985-01-01

    Research data on the aerodynamic behavior of baseballs and cricket and golf balls are summarized. Cricket balls and baseballs are roughly the same size and mass but have different stitch patterns. Both are thrown to follow paths that avoid a batter's swing, paths that can curve if aerodynamic forces on the balls' surfaces are asymmetric. Smoke tracer wind tunnel tests and pressure taps have revealed that the unbalanced side forces are induced by tripping the boundary layer on the seam side and producing turbulence. More particularly, the greater pressures are perpendicular to the seam plane and only appear when the balls travel at velocities high enough so that the roughness length matches the seam heigh. The side forces, once tripped, will increase with spin velocity up to a cut-off point. The enhanced lift coefficient is produced by the Magnus effect. The more complex stitching on a baseball permits greater variations in the flight path curve and, in the case of a knuckleball, the unsteady flow effects. For golf balls, the dimples trip the boundary layer and the high spin rate produces a lift coefficient maximum of 0.5, compared to a baseball's maximum of 0.3. Thus, a golf ball travels far enough for gravitational forces to become important.

  10. Aerodynamic challenges of ALT

    NASA Technical Reports Server (NTRS)

    Hooks, I.; Homan, D.; Romere, P. O.

    1985-01-01

    The approach and landing test (ALT) of the Space Shuttle Orbiter presented a number of unique challenges in the area of aerodynamics. The purpose of the ALT program was both to confirm the use of the Boeing 747 as a transport vehicle for ferrying the Orbiter across the country and to demonstrate the flight characteristics of the Orbiter in its approach and landing phase. Concerns for structural fatigue and performance dictated a tailcone be attached to the Orbiter for ferry and for the initial landing tests. The Orbiter with a tailcone attached presented additional challenges to the normal aft sting concept of wind tunnel testing. The landing tests required that the Orbiter be separated from the 747 at approximately 20,000 feet using aerodynamic forces to fly the vehicles apart. The concept required a complex test program to determine the relative effects of the two vehicles on each other. Also of concern, and tested, was the vortex wake created by the 747 and the means for the Orbiter to avoid it following separation.

  11. Fully integrated aerodynamic/dynamic optimization of helicopter rotor blades

    NASA Technical Reports Server (NTRS)

    Walsh, Joanne L.; Lamarsh, William J., II; Adelman, Howard M.

    1992-01-01

    A fully integrated aerodynamic/dynamic optimization procedure is described for helicopter rotor blades. The procedure combines performance and dynamic analyses with a general purpose optimizer. The procedure minimizes a linear combination of power required (in hover, forward flight, and maneuver) and vibratory hub shear. The design variables include pretwist, taper initiation, taper ratio, root chord, blade stiffnesses, tuning masses, and tuning mass locations. Aerodynamic constraints consist of limits on power required in hover, forward flight and maneuvers; airfoil section stall; drag divergence Mach number; minimum tip chord; and trim. Dynamic constraints are on frequencies, minimum autorotational inertia, and maximum blade weight. The procedure is demonstrated for two cases. In the first case, the objective function involves power required (in hover, forward flight and maneuver) and dynamics. The second case involves only hover power and dynamics. The designs from the integrated procedure are compared with designs from a sequential optimization approach in which the blade is first optimized for performance and then for dynamics. In both cases, the integrated approach is superior.

  12. Aerodynamic design using numerical optimization

    NASA Technical Reports Server (NTRS)

    Murman, E. M.; Chapman, G. T.

    1983-01-01

    The procedure of using numerical optimization methods coupled with computational fluid dynamic (CFD) codes for the development of an aerodynamic design is examined. Several approaches that replace wind tunnel tests, develop pressure distributions and derive designs, or fulfill preset design criteria are presented. The method of Aerodynamic Design by Numerical Optimization (ADNO) is described and illustrated with examples.

  13. On Wings: Aerodynamics of Eagles.

    ERIC Educational Resources Information Center

    Millson, David

    2000-01-01

    The Aerodynamics Wing Curriculum is a high school program that combines basic physics, aerodynamics, pre-engineering, 3D visualization, computer-assisted drafting, computer-assisted manufacturing, production, reengineering, and success in a 15-hour, 3-week classroom module. (JOW)

  14. Aerodynamics of a Party Balloon

    ERIC Educational Resources Information Center

    Cross, Rod

    2007-01-01

    It is well-known that a party balloon can be made to fly erratically across a room, but it can also be used for quantitative measurements of other aspects of aerodynamics. Since a balloon is light and has a large surface area, even relatively weak aerodynamic forces can be readily demonstrated or measured in the classroom. Accurate measurements…

  15. Unsteady aerodynamic modeling for arbitrary motions. [for active control techniques

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Results indicating that unsteady aerodynamic loads derived under the assumption of simple harmonic motions executed by airfoil or wing can be extended to arbitrary motions are summarized. The generalized Theodorsen (1953) function referable to loads due to simple harmonic oscillations of a wing section in incompressible flow, the Laplace inversion integral for unsteady aerodynamic loads, calculations of root loci of aeroelastic loads, and analysis of generalized compressible transient airloads are discussed.

  16. The design of missile's dome that fits both optical and aerodynamic needs

    NASA Astrophysics Data System (ADS)

    Wei, Qun; Zhang, Xin; Jia, Hongguang

    2010-10-01

    Optical guidance missiles requires a dome which fits both optical and aerodynamic needs when they attack at 3 Ma. In this study, ellipse is the figure chosen to be the dome's shape. The ellipticity ɛ is the main variable should to be decided. The optimized function was built by optical and aerodynamic performance function multiply by their weights. The optical and aerodynamic functions were all obtained by computational fluid dynamic (CFD) simulation's results after normalization. In this study, the optical and aerodynamic performances have equal weights, after optimzing the ellipticity ɛis 2 for the missile.

  17. CFD research, parallel computation and aerodynamic optimization

    NASA Technical Reports Server (NTRS)

    Ryan, James S.

    1995-01-01

    Over five years of research in Computational Fluid Dynamics and its applications are covered in this report. Using CFD as an established tool, aerodynamic optimization on parallel architectures is explored. The objective of this work is to provide better tools to vehicle designers. Submarine design requires accurate force and moment calculations in flow with thick boundary layers and large separated vortices. Low noise production is critical, so flow into the propulsor region must be predicted accurately. The High Speed Civil Transport (HSCT) has been the subject of recent work. This vehicle is to be a passenger vehicle with the capability of cutting overseas flight times by more than half. A successful design must surpass the performance of comparable planes. Fuel economy, other operational costs, environmental impact, and range must all be improved substantially. For all these reasons, improved design tools are required, and these tools must eventually integrate optimization, external aerodynamics, propulsion, structures, heat transfer and other disciplines.

  18. The aerodynamic challenges of SRB recovery

    NASA Technical Reports Server (NTRS)

    Bacchus, D. L.; Kross, D. A.; Moog, R. D.

    1985-01-01

    Recovery and reuse of the Space Shuttle solid rocket boosters was baselined to support the primary goal to develop a low cost space transportation system. The recovery system required for the 170,000-lb boosters was for the largest and heaviest object yet to be retrieved from exoatmospheric conditions. State-of-the-art design procedures were ground-ruled and development testing minimized to produce both a reliable and cost effective system. The ability to utilize the inherent drag of the boosters during the initial phase of reentry was a key factor in minimizing the parachute loads, size and weight. A wind tunnel test program was devised to enable the accurate prediction of booster aerodynamic characteristics. Concurrently, wind tunnel, rocket sled and air drop tests were performed to develop and verify the performance of the parachute decelerator subsystem. Aerodynamic problems encountered during the overall recovery system development and the respective solutions are emphasized.

  19. Sharp Hypervelocity Aerodynamic Research Probe

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Kolodziej, Paul; Rasky, Daniel J. (Technical Monitor)

    1996-01-01

    The objective of this flight demonstration is to deploy a slender-body hypervelocity aerodynamic research probe (SHARP) from an orbiting platform using a tether, deorbit and fly it along its aerothermal performance constraint, and recover it intact in mid-air. To accomplish this objective, two flight demonstrations are proposed. The first flight uses a blunt-body, tethered reentry experiment vehicle (TREV) to prove out tethered deployment technology for accurate entries, a complete SHARP electronics suite, and a new soft mid-air helicopter recovery technique. The second flight takes advantage of this launch and recovery capability to demonstrate revolutionary sharp body concepts for hypervelocity vehicles, enabled by new Ultra-High Temperature Ceramics (UHTCs) recently developed by Ames Research Center. Successful demonstration of sharp body hypersonic vehicle technologies could have radical impact on space flight capabilities, including: enabling global reentry cross range capability from Station, eliminating reentry communications blackout, and allowing new highly efficient launch systems incorporating air breathing propulsion and zeroth staging.

  20. Domain decomposition for aerodynamic and aeroacoustic analyses, and optimization

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay

    1995-01-01

    The overarching theme was the domain decomposition, which intended to improve the numerical solution technique for the partial differential equations at hand; in the present study, those that governed either the fluid flow, or the aeroacoustic wave propagation, or the sensitivity analysis for a gradient-based optimization. The role of the domain decomposition extended beyond the original impetus of discretizing geometrical complex regions or writing modular software for distributed-hardware computers. It induced function-space decompositions and operator decompositions that offered the valuable property of near independence of operator evaluation tasks. The objectives have gravitated about the extensions and implementations of either the previously developed or concurrently being developed methodologies: (1) aerodynamic sensitivity analysis with domain decomposition (SADD); (2) computational aeroacoustics of cavities; and (3) dynamic, multibody computational fluid dynamics using unstructured meshes.

  1. Reciprocity relations in aerodynamics

    NASA Technical Reports Server (NTRS)

    Heaslet, Max A; Spreiter, John R

    1953-01-01

    Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis. A number of examples are listed, including general integral theorems for lifting, rolling, and pitching wings and for wings in nonuniform downwash fields. Correspondence is also established between the buildup of circulation with time of a wing starting impulsively from rest and the buildup of lift of the same wing moving in the reverse direction into a sharp-edged gust.

  2. Risk functions for human and porcine eye rupture based on projectile characteristics of blunt objects.

    PubMed

    Kennedy, Eric A; Ng, Tracy P; McNally, Craig; Stitzel, Joel D; Duma, Stephan M

    2006-11-01

    Eye ruptures are among the most devastating eye injuries and can occur in automobile crashes, sporting impacts, and military events, where blunt projectile impacts to the eye can be encountered. The purpose of this study was to develop injury risk functions for globe rupture of both human and porcine eyes from blunt projectile impacts. This study was completed in two parts by combining published eye experiments with new test data. In the first part, data from 57 eye impact tests that were reported in the literature were analyzed. Projectile characteristics such as mass, cross-sectional area, and velocity, as well as injury outcome were noted for all tests. Data were sorted by species type and areas were identified where a paucity of data existed, based on the kinetic and normalized energy of assaulting objects. For the second part, a total of 126 projectile tests were performed on human and porcine eyes. Projectiles used for these tests included blunt aluminum projectiles, BBs, foam pellets, Airsoft pellets, and paintballs. Data for each projectile were recorded prior to testing and high-speed video was used to determine projectile velocity prior to striking the eye. In part three the data were pooled for a total of 183 eye impact tests, 83 human and 100 porcine, and were analyzed to develop the injury risk criteria. Binary logistic regression was used to develop injury risk functions based on kinetic and normalized energy. Probit analysis was used to estimate confidence intervals for the injury risk functions. Porcine eyes were found to be significantly stronger than human eyes in resisting globe rupture (p=0.01). For porcine eyes a 50% risk of globe rupture was found to be 71,145 J/m2, with a confidence interval of 63,245 J/m2 to 80,390 J/m2. Human eyes were found to have a 50% risk of globe rupture at a lower, 35,519 J/m2, with confidence intervals of 32,018 J/m2 to 40,641 J/m2. The results presented in this paper are useful in estimating the risk of globe

  3. Unsteady aerodynamic modeling for arbitrary motions

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.; Ashley, H.; Breakwell, J. V.

    1977-01-01

    A study is presented on the unsteady aerodynamic loads due to arbitrary motions of a thin wing and their adaptation for the calculation of response and true stability of aeroelastic modes. In an Appendix, the use of Laplace transform techniques and the generalized Theodorsen function for two-dimensional incompressible flow is reviewed. New applications of the same approach are shown also to yield airloads valid for quite general small motions. Numerical results are given for the two-dimensional supersonic case. Previously proposed approximate methods, starting from simple harmonic unsteady theory, are evaluated by comparison with exact results obtained by the present approach. The Laplace inversion integral is employed to separate the loads into 'rational' and 'nonrational' parts, of which only the former are involved in aeroelastic stability of the wing. Among other suggestions for further work, it is explained how existing aerodynamic computer programs may be adapted in a fairly straightforward fashion to deal with arbitrary transients.

  4. Rarefied-flow Shuttle aerodynamics model

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Larman, Kevin T.; Moats, Christina D.

    1993-01-01

    A rarefied-flow shuttle aerodynamic model spanning the hypersonic continuum to the free molecule-flow regime was formulated. The model development has evolved from the High Resolution Accelerometer Package (HiRAP) experiment conducted on the Orbiter since 1983. The complete model is described in detail. The model includes normal and axial hypersonic continuum coefficient equations as functions of angle-of-attack, body flap deflection, and elevon deflection. Normal and axial free molecule flow coefficient equations as a function of angle-of-attack are presented, along with flight derived rarefied-flow transition bridging formulae. Comparisons are made with data from the Operational Aerodynamic Design Data Book (OADDB), applicable wind-tunnel data, and recent flight data from STS-35 and STS-40. The flight-derived model aerodynamic force coefficient ratio is in good agreement with the wind-tunnel data and predicts the flight measured force coefficient ratios on STS-35 and STS-40. The model is not, however, in good agreement with the OADDB. But, the current OADDB does not predict the flight data force coefficient ratios of either STS-35 or STS-40 as accurately as the flight-derived model. Also, the OADDB differs with the wind-tunnel force coefficient ratio data.

  5. Face Memory and Object Recognition in Children with High-Functioning Autism or Asperger Syndrome and in Their Parents

    ERIC Educational Resources Information Center

    Kuusikko-Gauffin, Sanna; Jansson-Verkasalo, Eira; Carter, Alice; Pollock-Wurman, Rachel; Jussila, Katja; Mattila, Marja-Leena; Rahko, Jukka; Ebeling, Hanna; Pauls, David; Moilanen, Irma

    2011-01-01

    Children with Autism Spectrum Disorders (ASDs) have reported to have impairments in face, recognition and face memory, but intact object recognition and object memory. Potential abnormalities, in these fields at the family level of high-functioning children with ASD remains understudied despite, the ever-mounting evidence that ASDs are genetic and…

  6. Incidental and Context-Responsive Activation of Structure- and Function-Based Action Features during Object Identification

    ERIC Educational Resources Information Center

    Lee, Chia-lin; Middleton, Erica; Mirman, Daniel; Kalenine, Solene; Buxbaum, Laurel J.

    2013-01-01

    Previous studies suggest that action representations are activated during object processing, even when task-irrelevant. In addition, there is evidence that lexical-semantic context may affect such activation during object processing. Finally, prior work from our laboratory and others indicates that function-based ("use") and structure-based…

  7. Freight Wing Trailer Aerodynamics Final Technical Report

    SciTech Connect

    Sean Graham

    2007-10-31

    Freight Wing Incorporated utilized the opportunity presented by a DOE category two Inventions and Innovations grant to commercialize and improve upon aerodynamic technology for semi-tuck trailers, capable of decreasing heavy vehicle fuel consumption, related environmental damage, and U.S. consumption of foreign oil. Major project goals included the demonstration of aerodynamic trailer technology in trucking fleet operations, and the development and testing of second generation products. A great deal of past scientific research has demonstrated that streamlining box shaped semi-trailers can significantly reduce a truck’s fuel consumption. However, significant design challenges have prevented past concepts from meeting industry needs. Freight Wing utilized a 2003 category one Inventions and Innovations grant to develop practical solutions to trailer aerodynamics. Fairings developed for the front, rear, and bottom of standard semi-trailers together demonstrated a 7% improvement to fuel economy in scientific tests conducted by the Transportation Research Center (TRC). Operational tests with major trucking fleets proved the functionality of the products, which were subsequently brought to market. This category two grant enabled Freight Wing to further develop, test and commercialize its products, resulting in greatly increased understanding and acceptance of aerodynamic trailer technology. Commercialization was stimulated by offering trucking fleets 50% cost sharing on trial implementations of Freight Wing products for testing and evaluation purposes. Over 230 fairings were implemented through the program with 35 trucking fleets including industry leaders such as Wal-Mart, Frito Lay and Whole Foods. The feedback from these testing partnerships was quite positive with product performance exceeding fleet expectations in many cases. Fleet feedback also was also valuable from a product development standpoint and assisted the design of several second generation products

  8. Skylon Aerodynamics and SABRE Plumes

    NASA Technical Reports Server (NTRS)

    Mehta, Unmeel; Afosmis, Michael; Bowles, Jeffrey; Pandya, Shishir

    2015-01-01

    An independent partial assessment is provided of the technical viability of the Skylon aerospace plane concept, developed by Reaction Engines Limited (REL). The objectives are to verify REL's engineering estimates of airframe aerodynamics during powered flight and to assess the impact of Synergetic Air-Breathing Rocket Engine (SABRE) plumes on the aft fuselage. Pressure lift and drag coefficients derived from simulations conducted with Euler equations for unpowered flight compare very well with those REL computed with engineering methods. The REL coefficients for powered flight are increasingly less acceptable as the freestream Mach number is increased beyond 8.5, because the engineering estimates did not account for the increasing favorable (in terms of drag and lift coefficients) effect of underexpanded rocket engine plumes on the aft fuselage. At Mach numbers greater than 8.5, the thermal environment around the aft fuselage is a known unknown-a potential design and/or performance risk issue. The adverse effects of shock waves on the aft fuselage and plumeinduced flow separation are other potential risks. The development of an operational reusable launcher from the Skylon concept necessitates the judicious use of a combination of engineering methods, advanced methods based on required physics or analytical fidelity, test data, and independent assessments.

  9. Aerodynamics of a hybrid airship

    NASA Astrophysics Data System (ADS)

    Andan, Amelda Dianne; Asrar, Waqar; Omar, Ashraf A.

    2012-06-01

    The objective of this paper is to present the results of a numerical study of the aerodynamic parameters of a wingless and a winged-hull airship. The total forces and moment coefficients of the airships have been computed over a range of angles. The results obtained show that addition of a wing to a conventional airship increases the lift has three times the lifting force at positive angle of attack as compared to a wingless airship whereas the drag increases in the range of 19% to 58%. The longitudinal and directional stabilities were found to be statically stable, however, both the conventional airship and the hybrid or winged airships were found to have poor rolling stability. Wingless airship has slightly higher longitudinal stability than a winged airship. The winged airship has better directional stability than the wingless airship. The wingless airship only possesses static rolling stability in the range of yaw angles of -5° to 5°. On the contrary, the winged airship initially tested does not possess rolling stability at all. Computational fluid dynamics (CFD) simulations show that modifications to the wing placement and its dihedral have strong positive effect on the rolling stability. Raising the wings to the center of gravity and introducing a dihedral angle of 5° stabilizes the rolling motion of the winged airship.

  10. Aerodynamic flight control to increase payload capability of future launch vehicles

    NASA Technical Reports Server (NTRS)

    Cochran, John E., Jr.

    1995-01-01

    The development of new launch vehicles will require that designers use innovative approaches to achieve greater performance in terms of pay load capability. The objective of the work performed under this delivery order was to provide technical assistance to the Contract Officer's Technical Representative (COTR) in the development of ideas and concepts for increasing the payload capability of launch vehicles by incorporating aerodynamic controls. Although aerodynamic controls, such as moveable fins, are currently used on relatively small missiles, the evolution of large launch vehicles has been moving away from aerodynamic control. The COTR reasoned that a closer investigation of the use of aerodynamic controls on large vehicles was warranted.

  11. Aerodynamic flight control to increase payload capability of future launch vehicles

    NASA Astrophysics Data System (ADS)

    Cochran, John E., Jr.

    1995-02-01

    The development of new launch vehicles will require that designers use innovative approaches to achieve greater performance in terms of pay load capability. The objective of the work performed under this delivery order was to provide technical assistance to the Contract Officer's Technical Representative (COTR) in the development of ideas and concepts for increasing the payload capability of launch vehicles by incorporating aerodynamic controls. Although aerodynamic controls, such as moveable fins, are currently used on relatively small missiles, the evolution of large launch vehicles has been moving away from aerodynamic control. The COTR reasoned that a closer investigation of the use of aerodynamic controls on large vehicles was warranted.

  12. Constraints on the exploitation of the functional properties of objects in expert tool-using chimpanzees (Pan troglodytes).

    PubMed

    Povinelli, Daniel J; Frey, Scott H

    2016-09-01

    Many species exploit immediately apparent dimensions of objects during tool use and manufacture and operate over internal perceptual representations of objects (they move and reorient objects in space, have rules of operation to deform or modify objects, etc). Humans, however, actively test for functionally relevant object properties before such operations begin, even when no previous percepts of a particular object's qualities in the domain have been established. We hypothesize that such prospective diagnostic interventions are a human specialization of cognitive function that has been entirely overlooked in the neuropsychological literature. We presented chimpanzees with visually identical rakes: one was functional for retrieving a food reward; the other was non-functional (its base was spring-loaded). Initially, they learned that only the functional tool could retrieve a distant reward. In test 1, we explored if they would manually test for the rakes' rigidity during tool selection, but before using it. We found no evidence of such behavior. In test 2, we obliged the apes to deform the non-functional tool's base before using it, in order to evaluate whether this would cause them to switch rakes. It did not. Tests 3-6 attempted to focus the apes' attention on the functionally relevant property (rigidity). Although one ape eventually learned to abandon the non-functional rake before using it, she still did not attempt to test the rakes for rigidity prior to use. While these results underscore the ability of chimpanzees to use novel tools, at the same time they point toward a fundamental (and heretofore unexplored) difference in causal reasoning between humans and apes. We propose that this behavioral difference reflects a human specialization in how object properties are represented, which could have contributed significantly to the evolution of our technological culture. We discuss developing a new line of evolutionarily motivated neuropsychological research on

  13. 1997 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    Baize, Daniel G. (Editor)

    1999-01-01

    The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Aerodynamic Performance Workshop on February 25-28, 1997. The workshop was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag, prediction and minimization), High-Lift, Flight Controls, Supersonic Laminar Flow Control, and Sonic Boom Prediction. The workshop objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientist and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT Motion Simulator results were presented along with executives summaries for all the Aerodynamic Performance technology areas.

  14. Color changes in objects in natural scenes as a function of observation distance and weather conditions.

    PubMed

    Romero, Javier; Luzón-González, Raúl; Nieves, Juan L; Hernández-Andrés, Javier

    2011-10-01

    We have analyzed the changes in the color of objects in natural scenes due to atmospheric scattering according to changes in the distance of observation. Hook-shaped curves were found in the chromaticity diagram when the object moved from zero distance to long distances, where the object chromaticity coordinates approached the color coordinates of the horizon. This trend is the result of the combined effect of attenuation in the direct light arriving to the observer from the object and the airlight added during its trajectory. Atmospheric scattering leads to a fall in the object's visibility, which is measurable as a difference in color between the object and the background (taken here to be the horizon). Focusing on color difference instead of luminance difference could produce different visibility values depending on the color tolerance used. We assessed the cone-excitation ratio constancy for several objects at different distances. Affine relationships were obtained when an object's cone excitations were represented both at zero distance and increasing distances. These results could help to explain color constancy in natural scenes for objects at different distances, a phenomenon that has been pointed out by different authors. PMID:22016233

  15. A class of stochastic optimization problems with one quadratic & several linear objective functions and extended portfolio selection model

    NASA Astrophysics Data System (ADS)

    Xu, Jiuping; Li, Jun

    2002-09-01

    In this paper a class of stochastic multiple-objective programming problems with one quadratic, several linear objective functions and linear constraints has been introduced. The former model is transformed into a deterministic multiple-objective nonlinear programming model by means of the introduction of random variables' expectation. The reference direction approach is used to deal with linear objectives and results in a linear parametric optimization formula with a single linear objective function. This objective function is combined with the quadratic function using the weighted sums. The quadratic problem is transformed into a linear (parametric) complementary problem, the basic formula for the proposed approach. The sufficient and necessary conditions for (properly, weakly) efficient solutions and some construction characteristics of (weakly) efficient solution sets are obtained. An interactive algorithm is proposed based on reference direction and weighted sums. Varying the parameter vector on the right-hand side of the model, the DM can freely search the efficient frontier with the model. An extended portfolio selection model is formed when liquidity is considered as another objective to be optimized besides expectation and risk. The interactive approach is illustrated with a practical example.

  16. Computational aerodynamics and artificial intelligence

    NASA Technical Reports Server (NTRS)

    Kutler, P.; Mehta, U. B.

    1984-01-01

    Some aspects of artificial intelligence are considered and questions are speculated on, including how knowledge-based systems can accelerate the process of acquiring new knowledge in aerodynamics, how computational fluid dynamics may use 'expert' systems and how expert systems may speed the design and development process. The anatomy of an idealized expert system called AERODYNAMICIST is discussed. Resource requirements are examined for using artificial intelligence in computational fluid dynamics and aerodynamics. Considering two of the essentials of computational aerodynamics - reasoniing and calculating - it is believed that a substantial part of the reasoning can be achieved with artificial intelligence, with computers being used as reasoning machines to set the stage for calculating. Expert systems will probably be new assets of institutions involved in aeronautics for various tasks of computational aerodynamics.

  17. Computational aerodynamics and artificial intelligence

    NASA Technical Reports Server (NTRS)

    Mehta, U. B.; Kutler, P.

    1984-01-01

    The general principles of artificial intelligence are reviewed and speculations are made concerning how knowledge based systems can accelerate the process of acquiring new knowledge in aerodynamics, how computational fluid dynamics may use expert systems, and how expert systems may speed the design and development process. In addition, the anatomy of an idealized expert system called AERODYNAMICIST is discussed. Resource requirements for using artificial intelligence in computational fluid dynamics and aerodynamics are examined. Three main conclusions are presented. First, there are two related aspects of computational aerodynamics: reasoning and calculating. Second, a substantial portion of reasoning can be achieved with artificial intelligence. It offers the opportunity of using computers as reasoning machines to set the stage for efficient calculating. Third, expert systems are likely to be new assets of institutions involved in aeronautics for various tasks of computational aerodynamics.

  18. Predictive Potential of Flux Balance Analysis of Saccharomyces cerevisiae Using as Optimization Function Combinations of Cell Compartmental Objectives

    PubMed Central

    García Sánchez, Carlos Eduardo; Vargas García, César Augusto; Torres Sáez, Rodrigo Gonzalo

    2012-01-01

    Background The main objective of flux balance analysis (FBA) is to obtain quantitative predictions of metabolic fluxes of an organism, and it is necessary to use an appropriate objective function to guarantee a good estimation of those fluxes. Methodology In this study, the predictive performance of FBA was evaluated, using objective functions arising from the linear combination of different cellular objectives. This approach is most suitable for eukaryotic cells, owing to their multiplicity of cellular compartments. For this reason, Saccharomyces cerevisiae was used as model organism, and its metabolic network was represented using the genome-scale metabolic model iMM904. As the objective was to evaluate the predictive performance from the FBA using the kind of objective function previously described, substrate uptake and oxygen consumption were the only input data used for the FBA. Experimental information about microbial growth and exchange of metabolites with the environment was used to assess the quality of the predictions. Conclusions The quality of the predictions obtained with the FBA depends greatly on the knowledge of the oxygen uptake rate. For the most of studied classifications, the best predictions were obtained with “maximization of growth”, and with some combinations that include this objective. However, in the case of exponential growth with unknown oxygen exchange flux, the objective function “maximization of growth, plus minimization of NADH production in cytosol, plus minimization of NAD(P)H consumption in mitochondrion” gave much more accurate estimations of fluxes than the obtained with any other objective function explored in this study. PMID:22912775

  19. Dynamic soaring: aerodynamics for albatrosses

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2009-01-01

    Albatrosses have evolved to soar and glide efficiently. By maximizing their lift-to-drag ratio L/D, albatrosses can gain energy from the wind and can travel long distances with little effort. We simplify the difficult aerodynamic equations of motion by assuming that albatrosses maintain a constant L/D. Analytic solutions to the simplified equations provide an instructive and appealing example of fixed-wing aerodynamics suitable for undergraduate demonstration.

  20. Supersonic aerodynamics of delta wings

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.

    1988-01-01

    Through the empirical correlation of experimental data and theoretical analysis, a set of graphs has been developed which summarize the inviscid aerodynamics of delta wings at supersonic speeds. The various graphs which detail the aerodynamic performance of delta wings at both zero-lift and lifting conditions were then employed to define a preliminary wing design approach in which both the low-lift and high-lift design criteria were combined to define a feasible design space.

  1. An adaptive strategy on the error of the objective functions for uncertainty-based derivative-free optimization

    NASA Astrophysics Data System (ADS)

    Fusi, F.; Congedo, P. M.

    2016-03-01

    In this work, a strategy is developed to deal with the error affecting the objective functions in uncertainty-based optimization. We refer to the problems where the objective functions are the statistics of a quantity of interest computed by an uncertainty quantification technique that propagates some uncertainties of the input variables through the system under consideration. In real problems, the statistics are computed by a numerical method and therefore they are affected by a certain level of error, depending on the chosen accuracy. The errors on the objective function can be interpreted with the abstraction of a bounding box around the nominal estimation in the objective functions space. In addition, in some cases the uncertainty quantification methods providing the objective functions also supply the possibility of adaptive refinement to reduce the error bounding box. The novel method relies on the exchange of information between the outer loop based on the optimization algorithm and the inner uncertainty quantification loop. In particular, in the inner uncertainty quantification loop, a control is performed to decide whether a refinement of the bounding box for the current design is appropriate or not. In single-objective problems, the current bounding box is compared to the current optimal design. In multi-objective problems, the decision is based on the comparison of the error bounding box of the current design and the current Pareto front. With this strategy, fewer computations are made for clearly dominated solutions and an accurate estimate of the objective function is provided for the interesting, non-dominated solutions. The results presented in this work prove that the proposed method improves the efficiency of the global loop, while preserving the accuracy of the final Pareto front.

  2. Unsteady Aerodynamics Experiment Phase VI: Wind Tunnel Test Configurations and Available Data Campaigns

    SciTech Connect

    Hand, M. M.; Simms, D. A.; Fingersh, L. J.; Jager, D. W.; Cotrell, J. R.; Schreck, S.; Larwood, S. M.

    2001-12-01

    The primary objective of the insteady aerodynamics experiment was to provide information needed to quantify the full-scale, three-dimensional aerodynamic behavior of horizontal-axis wind turbines. This report is intended to familiarize the user with the entire scope of the wind tunnel test and to support the use of the resulting data.

  3. Naming as a Function of Linguistic Form-Class and Object Categories.

    ERIC Educational Resources Information Center

    Akiyama, M. Michael; Wilcox, Sharon A.

    1993-01-01

    Experiments with groups of 30 children (aged 3 through 6) and 32 children (aged 5 through 8) showed that (1) children use linguistic form-class information with familiar discrete objects, (2) children do not use linguistic form-class information with familiar food, and (3) children use only object category information with unfamiliar items.…

  4. Growing Mathematical Objects in the Classroom--The Case of Function

    ERIC Educational Resources Information Center

    Nachlieli, Talli; Tabach, Michal

    2012-01-01

    This article is devoted to some of the educational quandaries stemming from the fact that mathematics is a discourse that creates its own objects. More specifically, we ask how the participants of classroom learning-teaching processes cope with the seemingly paradoxical situation in which they are supposed to talk about objects, of the existence…

  5. Color-Function Categories that Prime Infants to Use Color Information in an Object Individuation Task

    ERIC Educational Resources Information Center

    Wilcox, Teresa; Woods, Rebecca; Chapa, Catherine

    2008-01-01

    There is evidence for developmental hierarchies in the type of information to which infants attend when reasoning about objects. Investigators have questioned the origin of these hierarchies and how infants come to identify new sources of information when reasoning about objects. The goal of the present experiments was to shed light on this debate…

  6. Objects, Numbers, Fingers, Space: Clustering of Ventral and Dorsal Functions in Young Children and Adults

    ERIC Educational Resources Information Center

    Chinello, Alessandro; Cattani, Veronica; Bonfiglioli, Claudia; Dehaene, Stanislas; Piazza, Manuela

    2013-01-01

    In the primate brain, sensory information is processed along two partially segregated cortical streams: the ventral stream, mainly coding for objects' shape and identity, and the dorsal stream, mainly coding for objects' quantitative information (including size, number, and spatial position). Neurophysiological measures indicate that…

  7. The Development of Symbolic Coordination: Representation of Imagined Objects, Executive Function, and Theory of Mind

    ERIC Educational Resources Information Center

    Dick, Anthony Steven; Overton, Willis F.; Kovacs, Stacie L.

    2005-01-01

    Children's developing competence with symbolic representations was assessed in 3 studies. Study 1 examined the hypothesis that the production of imaginary symbolic objects in pantomime requires the simultaneous coordination of the dual representations of a dynamic action and a symbolic object. We explored this coordination of symbolic…

  8. Classroom Engagement towards Using Definitions for Developing Mathematical Objects: The Case of Function

    ERIC Educational Resources Information Center

    Tabach, Michal; Nachlieli, Talli

    2015-01-01

    For mathematicians, definitions are the ultimate tool for reaching agreement about the nature and properties of mathematical objects. As research in school mathematics has revealed, however, mathematics learners are often reluctant, perhaps even unable, to help themselves with definitions while categorizing mathematical objects. In the research…

  9. The Function of Words: Distinct Neural Correlates for Words Denoting Differently Manipulable Objects

    ERIC Educational Resources Information Center

    Rueschemeyer, Shirley-Ann; van Rooij, Daan; Lindemann, Oliver; Willems, Roel M.; Bekkering, Harold

    2010-01-01

    Recent research indicates that language processing relies on brain areas dedicated to perception and action. For example, processing words denoting manipulable objects has been shown to activate a fronto-parietal network involved in actual tool use. This is suggested to reflect the knowledge the subject has about how objects are moved and used.…

  10. Aerodynamics for the Mars Phoenix Entry Capsule

    NASA Technical Reports Server (NTRS)

    Edquist, Karl T.; Desai, Prasun N.; Schoenenberger, Mark

    2008-01-01

    Pre-flight aerodynamics data for the Mars Phoenix entry capsule are presented. The aerodynamic coefficients were generated as a function of total angle-of-attack and either Knudsen number, velocity, or Mach number, depending on the flight regime. The database was constructed using continuum flowfield computations and data from the Mars Exploration Rover and Viking programs. Hypersonic and supersonic static coefficients were derived from Navier-Stokes solutions on a pre-flight design trajectory. High-altitude data (free-molecular and transitional regimes) and dynamic pitch damping characteristics were taken from Mars Exploration Rover analysis and testing. Transonic static coefficients from Viking wind tunnel tests were used for capsule aerodynamics under the parachute. Static instabilities were predicted at two points along the reference trajectory and were verified by reconstructed flight data. During the hypersonic instability, the capsule was predicted to trim at angles as high as 2.5 deg with an on-axis center-of-gravity. Trim angles were predicted for off-nominal pitching moment (4.2 deg peak) and a 5 mm off-axis center-ofgravity (4.8 deg peak). Finally, hypersonic static coefficient sensitivities to atmospheric density were predicted to be within uncertainty bounds.

  11. Aerodynamic sampling for landmine trace detection

    NASA Astrophysics Data System (ADS)

    Settles, Gary S.; Kester, Douglas A.

    2001-10-01

    Electronic noses and similar sensors show promise for detecting buried landmines through the explosive trace signals they emit. A key step in this detection is the sampler or sniffer, which acquires the airborne trace signal and presents it to the detector. Practicality demands no physical contact with the ground. Further, both airborne particulates and molecular traces must be sampled. Given a complicated minefield terrain and microclimate, this becomes a daunting chore. Our prior research on canine olfactory aerodynamics revealed several ways that evolution has dealt with such problems: 1) proximity of the sniffer to the scent source is important, 2) avoid exhaling back into the scent source, 3) use an aerodynamic collar on the sniffer inlet, 4) use auxiliary airjets to stir up surface particles, and 5) manage the 'impedance mismatch' between sniffer and sensor airflows carefully. Unfortunately, even basic data on aerodynamic sniffer performance as a function of inlet-tube and scent-source diameters, standoff distance, etc., have not been previously obtained. A laboratory-prototype sniffer was thus developed to provide guidance for landmine trace detectors. Initial experiments with this device are the subject of this paper. For example, a spike in the trace signal is observed upon starting the sniffer airflow, apparently due to rapid depletion of the available signal-laden air. Further, shielding the sniffer from disruptive ambient airflows arises as a key issue in sampling efficiency.

  12. Self-rated and informant-rated everyday function in comparison to objective markers of Alzheimer's disease.

    PubMed

    Rueda, Alicia D; Lau, Karen M; Saito, Naomi; Harvey, Danielle; Risacher, Shannon L; Aisen, Paul S; Petersen, Ronald C; Saykin, Andrew J; Farias, Sarah Tomaszewski

    2015-09-01

    It is recognized that individuals with mild cognitive impairment (MCI) already demonstrate difficulty in aspects of daily functioning, which predicts disease progression. This study examined the relationship between self- versus informant-report of functional ability, and how those reports relate to objective disease measures across the disease spectrum (i.e. cognitively normal, MCI, Alzheimer's disease). A total of 1080 subjects with self- and/or informant-rated Everyday Cognition questionnaires were included. Objective measures included cognitive functioning, structural brain atrophy, cerebrospinal fluid abnormalities, and a marker of amyloid deposition using positron emission tomography with [18F]AV45 (florbetapir). Overall, informant-report was consistently more associated with objective markers of disease than self-report although self-reported functional status may still have some utility in early disease. PMID:25449531

  13. Aerodynamics of Wiffle Balls

    NASA Astrophysics Data System (ADS)

    Utvich, Alexis; Jemmott, Colin; Logan, Sheldon; Rossmann, Jenn

    2003-11-01

    A team of undergraduate students has performed experiments on Wiffle balls in the Harvey Mudd College wind tunnel facility. Wiffle balls are of particular interest because they can attain a curved trajectory with little or no pitcher-imparted spin. The reasons behind this have not previously been quantified formally. A strain gauge device was designed and constructed to measure the lift and drag forces on the Wiffle ball; a second device to measure lift and drag on a spinning ball was also developed. Experiments were conducted over a range of Reynolds numbers corresponding to speeds of roughly 0-40 mph. Lift forces of up to 0.2 N were measured for a Wiffle ball at 40 mph. This is believed to be due to air flowing into the holes on the Wiffle ball in addition to the effect of the holes on external boundary layer separation. A fog-based flow visualization system was developed in order to provide a deeper qualitative understanding of what occurred in the flowfield surrounding the ball. The data and observations obtained in this study support existing assumptions about Wiffle ball aerodynamics and begin to elucidate the mechanisms involved in Wiffle ball flight.

  14. Aerodynamics of badminton shuttlecocks

    NASA Astrophysics Data System (ADS)

    Verma, Aekaansh; Desai, Ajinkya; Mittal, Sanjay

    2013-08-01

    A computational study is carried out to understand the aerodynamics of shuttlecocks used in the sport of badminton. The speed of the shuttlecock considered is in the range of 25-50 m/s. The relative contribution of various parts of the shuttlecock to the overall drag is studied. It is found that the feathers, and the net in the case of a synthetic shuttlecock, contribute the maximum. The gaps, in the lower section of the skirt, play a major role in entraining the surrounding fluid and causing a difference between the pressure inside and outside the skirt. This pressure difference leads to drag. This is confirmed via computations for a shuttlecock with no gaps. The synthetic shuttle experiences more drag than the feather model. Unlike the synthetic model, the feather shuttlecock is associated with a swirling flow towards the end of the skirt. The effect of the twist angle of the feathers on the drag as well as the flow has also been studied.

  15. Functional Evaluation of Hidden Figures Object Analysis in Children with Autistic Disorder

    ERIC Educational Resources Information Center

    Malisza, Krisztina L.; Clancy, Christine; Shiloff, Deborah; Foreman, Derek; Holden, Jeanette; Jones, Cheryl; Paulson, K.; Summers, Randy; Yu, C. T.; Chudley, Albert E.

    2011-01-01

    Functional magnetic resonance imaging (fMRI) during performance of a hidden figures task (HFT) was used to compare differences in brain function in children diagnosed with autism disorder (AD) compared to children with attention-deficit/hyperactivity disorder (ADHD) and typical controls (TC). Overall greater functional MRI activity was observed in…

  16. The aerodynamics of supersonic parachutes

    SciTech Connect

    Peterson, C.W.

    1987-06-01

    A discussion of the aerodynamics and performance of parachutes flying at supersonic speeds is the focus of this paper. Typical performance requirements for supersonic parachute systems are presented, followed by a review of the literature on supersonic parachute configurations and their drag characteristics. Data from a recent supersonic wind tunnel test series is summarized. The value and limitations of supersonic wind tunnel data on hemisflo and 20-degree conical ribbon parachutes behind several forebody shapes and diameters are discussed. Test techniques were derived which avoided many of the opportunities to obtain erroneous supersonic parachute drag data in wind tunnels. Preliminary correlations of supersonic parachute drag with Mach number, forebody shape and diameter, canopy porosity, inflated canopy diameter and stability are presented. Supersonic parachute design considerations are discussed and applied to a M = 2 parachute system designed and tested at Sandia. It is shown that the performance of parachutes in supersonic flows is a strong function of parachute design parameters and their interactions with the payload wake.

  17. Genetic Association of Objective Sleep Phenotypes with a Functional Polymorphism in the Neuropeptide S Receptor Gene

    PubMed Central

    Spada, Janek; Sander, Christian; Burkhardt, Ralph; Häntzsch, Madlen; Mergl, Roland; Scholz, Markus; Hegerl, Ulrich; Hensch, Tilman

    2014-01-01

    Background The neuropeptide S receptor (NPSR1) and its ligand neuropeptide S (NPS) have received increased attention in the last few years, as both establish a previously unknown system of neuromodulation. Animal research studies have suggested that NPS may be involved in arousal/wakefulness and may also have a crucial role in sleep regulation. The single nucleotide polymorphism (SNP) rs324981 in NPSR1 has begun to shed light on a function of the NPS-system in human sleep regulation. Due to an amino acid exchange, the T-allele leads to an increased sensitivity of the NPSR1. In the only genome-wide association study to date on circadian sleep parameters in humans, an association was found between rs324981 and regular bedtime. However, the sleep parameters in this study were only measured by self-rating. Therefore, our study aimed to replicate these findings using an objective measure of sleep. Methods The study included n = 393 white subjects (62–79 years) who participated in an actigraphic assessment for determining sleep duration, rest duration, sleep onset, rest onset and sleep onset latency. Genotyping of the SNP rs324981 was performed using the TaqMan OpenArray System. Results The genotype at rs324981 was not significantly associated with rest onset (bedtime) or sleep onset (p = .146 and p = .199, respectively). However, the SNP showed a significant effect on sleep- and rest duration (p = .007 and p = .003, respectively). Subjects that were homozygous for the minor T-allele had a significantly decreased sleep- and rest duration compared to A-allele carriers. Conclusion The results of this study indicate that the sleep pattern in humans is influenced by the NPS-system. However, the previously reported association between bedtime and rs324981 could not be confirmed. The current finding of decreased sleep duration in T/T allele carriers is in accordance with studies in rodents reporting similar results after NPS application. PMID:24896296

  18. Calibration method of laser plane equation for vision measurement adopting objective function of uniform horizontal height of feature points

    NASA Astrophysics Data System (ADS)

    Xu, Guan; Hao, Zhaobing; Li, Xiaotao; Su, Jian; Liu, Huanping; Zhang, Xinyuan

    2016-02-01

    A calibration method with an objective function generated from a uniform horizontal height is presented in this work for the laser plane in active vision measurement. A height target is developed with a center mark as the initial point of the uniform height. The height target is located on the horizontal plane of the 3D calibration board so that the horizontal plane is considered as the terminal of the uniform horizontal height. Based on the pinhole model of the camera and the laser plane equation, we model the objective function to find the optimal coefficients of the laser plane equation. The goal of the objective function is the smallest difference of the uniform height and the reconstructed height according to the feature points of the target. The objective function is optimized by the local particle swarm optimization. The calibrated global equation of a laser plane is obtained from the optimal value 1.153 × 103 of the objective function in the experiments. Two projective laser lines of the calibration laser plane cover the original laser lines in the image. The reconstruction errors of the calibration plane are also analyzed in discussions.

  19. Global Nonlinear Parametric Modeling with Application to F-16 Aerodynamics

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    1997-01-01

    A global nonlinear parametric modeling technique is described and demonstrated. The technique uses multivariate orthogonal modeling functions generated from the data to determine nonlinear model structure, then expands each retained modeling function into an ordinary multivariate polynomial. The final model form is a finite multivariate power series expansion for the dependent variable in terms of the independent variables. Partial derivatives of the identified models can be used to assemble globally valid linear parameter varying models. The technique is demonstrated by identifying global nonlinear parametric models for nondimensional aerodynamic force and moment coefficients from a subsonic wind tunnel database for the F-16 fighter aircraft. Results show less than 10% difference between wind tunnel aerodynamic data and the nonlinear parameterized model for a simulated doublet maneuver at moderate angle of attack. Analysis indicated that the global nonlinear parametric models adequately captured the multivariate nonlinear aerodynamic functional dependence.

  20. Global Nonlinear Parametric Modeling with Application to F-16 Aerodynamics

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    1998-01-01

    A global nonlinear parametric modeling technique is described and demonstrated. The technique uses multivariate orthogonal modeling functions generated from the data to determine nonlinear model structure, then expands each retained modeling function into an ordinary multivariate polynomial. The final model form is a finite multivariate power series expansion for the dependent variable in terms of the independent variables. Partial derivatives of the identified models can be used to assemble globally valid linear parameter varying models. The technique is demonstrated by identifying global nonlinear parametric models for nondimensional aerodynamic force and moment coefficients from a subsonic wind tunnel database for the F-16 fighter aircraft. Results show less than 10% difference between wind tunnel aerodynamic data and the nonlinear parameterized model for a simulated doublet maneuver at moderate angle of attack. Analysis indicated that the global nonlinear parametric models adequately captured the multivariate nonlinear aerodynamic functional dependence.

  1. The associations of objectively measured physical activity and sedentary time with cognitive functions in school-aged children.

    PubMed

    Syväoja, Heidi J; Tammelin, Tuija H; Ahonen, Timo; Kankaanpää, Anna; Kantomaa, Marko T

    2014-01-01

    Low levels of physical activity among children have raised concerns over the effects of a physically inactive lifestyle, not only on physical health but also on cognitive prerequisites of learning. This study examined how objectively measured and self-reported physical activity and sedentary behavior are associated with cognitive functions in school-aged children. The study population consisted of 224 children from five schools in the Jyväskylä school district in Finland (mean age 12.2 years; 56% girls), who participated in the study in the spring of 2011. Physical activity and sedentary time were measured objectively for seven consecutive days using the ActiGraph GT1M/GT3X accelerometer. Self-reported moderate to vigorous physical activity (MVPA) and screen time were evaluated with the questions used in the "WHO Health Behavior in School-aged Children" study. Cognitive functions including visual memory, executive functions and attention were evaluated with a computerized Cambridge Neuropsychological Test Automated Battery by using five different tests. Structural equation modeling was applied to examine how objectively measured and self-reported MVPA and sedentary behavior were associated with cognitive functions. High levels of objectively measured MVPA were associated with good performance in the reaction time test. High levels of objectively measured sedentary time were associated with good performance in the sustained attention test. Objectively measured MVPA and sedentary time were not associated with other measures of cognitive functions. High amount of self-reported computer/video game play was associated with weaker performance in working memory test, whereas high amount of computer use was associated with weaker performance in test measuring shifting and flexibility of attention. Self-reported physical activity and total screen time were not associated with any measures of cognitive functions. The results of the present study propose that physical

  2. The Associations of Objectively Measured Physical Activity and Sedentary Time with Cognitive Functions in School-Aged Children

    PubMed Central

    Syväoja, Heidi J.; Tammelin, Tuija H.; Ahonen, Timo; Kankaanpää, Anna; Kantomaa, Marko T.

    2014-01-01

    Low levels of physical activity among children have raised concerns over the effects of a physically inactive lifestyle, not only on physical health but also on cognitive prerequisites of learning. This study examined how objectively measured and self-reported physical activity and sedentary behavior are associated with cognitive functions in school-aged children. The study population consisted of 224 children from five schools in the Jyväskylä school district in Finland (mean age 12.2 years; 56% girls), who participated in the study in the spring of 2011. Physical activity and sedentary time were measured objectively for seven consecutive days using the ActiGraph GT1M/GT3X accelerometer. Self-reported moderate to vigorous physical activity (MVPA) and screen time were evaluated with the questions used in the “WHO Health Behavior in School-aged Children” study. Cognitive functions including visual memory, executive functions and attention were evaluated with a computerized Cambridge Neuropsychological Test Automated Battery by using five different tests. Structural equation modeling was applied to examine how objectively measured and self-reported MVPA and sedentary behavior were associated with cognitive functions. High levels of objectively measured MVPA were associated with good performance in the reaction time test. High levels of objectively measured sedentary time were associated with good performance in the sustained attention test. Objectively measured MVPA and sedentary time were not associated with other measures of cognitive functions. High amount of self-reported computer/video game play was associated with weaker performance in working memory test, whereas high amount of computer use was associated with weaker performance in test measuring shifting and flexibility of attention. Self-reported physical activity and total screen time were not associated with any measures of cognitive functions. The results of the present study propose that physical

  3. Recent advances in aerodynamic energy concept for flutter suppression and gust alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Nissim, E.

    1977-01-01

    Control laws are derived, by using realizable transfer functions, which permit relaxation of the stability requirements of the aerodynamic energy concept. The resulting aerodynamic eigenvalues indicate that both the trailing edge and the leading edge-trailing edge control systems can be made more effective. These control laws permit the introduction of aerodynamic damping and stiffness terms in accordance with the requirements of any specific system. Flutter suppression and gust alleviation problems can now be treated by either a trailing edge control system or by a leading edge-trailing edge control system by using the aerodynamic energy concept. Results are applicable to a wide class of aircraft operating at subsonic Mach numbers.

  4. Computational investigation on the application of using microjets as active aerodynamic load control for wind turbines

    NASA Astrophysics Data System (ADS)

    Blaylock, Myra Louise

    A fast, efficient way to control loads on industrial scale turbines is important for the growth of the wind industry. Active Aerodynamic Load Control (AALC) is one area which addresses this need. In particular, microjets, which are pneumatic jets located at the trailing edge of a wind turbine blade and blow perpendicular to the blade surface, are a possible AALC candidate. First, the Computational Fluid Dynamics (CFD) solver OVERFLOW is used to explore the effects of a microjet on lift, drag, and pitching moment. Then the interaction between an aerodynamic disturbance and an airfoil equipped with a microjet is modeled. The object of this dissertation is to investigate microtabs as viable AALC devices by presenting their aerodynamic properties and testing whether a proportional-integral (PI) controlled jets can alleviate loads caused by wind gusts. The use of CFD to simulate a microjet is validated by comparing the results to both previous experiments found in the literature as well as wind tunnel tests completed at UC Davis. The aerodynamic effectiveness of the jet is investigated as a function of various parameters such as Reynolds number, angle of attack, and the momentum coefficient of the jet. The effects of the microjet are found to be very similar to another AALC device, the microtab. An aerodynamic disturbance is simulated, and a control algorithm which is incorporated into the OVERFLOW code is used to activate the microjet, thus reducing the change of the blade load due to the gust. Finally, a more realistic model is made by adding both a linear and a torsional spring and damper to represent the blade movement. This two-degree of freedom system shows that during a gust the vertical blade movement is reduced when the microjets are activated. Microjets are found to work well to alleviate the changes in aerodynamic loads felt by the airfoil, and are therefore a good candidate for a practical AALC device. However, further investigation is needed in the areas of

  5. Age-based hiring discrimination as a function of equity norms and self-perceived objectivity.

    PubMed

    Lindner, Nicole M; Graser, Alexander; Nosek, Brian A

    2014-01-01

    Participants completed a questionnaire priming them to perceive themselves as either objective or biased, either before or after evaluating a young or old job applicant for a position linked to youthful stereotypes. Participants agreed that they were objective and tended to disagree that they were biased. Extending past research, both the objective and bias priming conditions led to an increase in age discrimination compared to the control condition. We also investigated whether equity norms reduced age discrimination, by manipulating the presence or absence of an equity statement reminding decision-makers of the legal prohibitions against discrimination "on the basis of age, disability, national or ethnic origin, race, religion, or sex." The presence of equity norms increased enthusiasm for both young and old applicants when participants were not already primed to think of themselves as objective, but did not reduce age-based hiring discrimination. Equity norms had no effect when individuals thought of themselves as objective - they preferred the younger more than the older job applicant. However, the presence of equity norms did affect individuals' perceptions of which factors were important to their hiring decisions, increasing the perceived importance of applicants' expertise and decreasing the perceived importance of the applicants' age. The results suggest that interventions that rely exclusively on decision-makers' intentions to behave equitably may be ineffective. PMID:24465429

  6. Time-varying effective connectivity during visual object naming as a function of semantic demands.

    PubMed

    Poch, Claudia; Garrido, Marta I; Igoa, José Manuel; Belinchón, Mercedes; García-Morales, Irene; Campo, Pablo

    2015-06-10

    Accumulating evidence suggests that visual object understanding involves a rapid feedforward sweep, after which subsequent recurrent interactions are necessary. The extent to which recurrence plays a critical role in object processing remains to be determined. Recent studies have demonstrated that recurrent processing is modulated by increasing semantic demands. Differentially from previous studies, we used dynamic causal modeling to model neural activity recorded with magnetoencephalography while 14 healthy humans named two sets of visual objects that differed in the degree of semantic accessing demands, operationalized in terms of the values of basic psycholinguistic variables associated with the presented objects (age of acquisition, frequency, and familiarity). This approach allowed us to estimate the directionality of the causal interactions among brain regions and their associated connectivity strengths. Furthermore, to understand the dynamic nature of connectivity (i.e., the chronnectome; Calhoun et al., 2014) we explored the time-dependent changes of effective connectivity during a period (200-400 ms) where adding semantic-feature information improves modeling and classifying visual objects, at 50 ms increments. First, we observed a graded involvement of backward connections, that became active beyond 200 ms. Second, we found that semantic demands caused a suppressive effect in the backward connection from inferior frontal cortex (IFC) to occipitotemporal cortex over time. These results complement those from previous studies underscoring the role of IFC as a common source of top-down modulation, which drives recurrent interactions with more posterior regions during visual object recognition. Crucially, our study revealed the inhibitory modulation of this interaction in situations that place greater demands on the conceptual system. PMID:26063911

  7. Application of CAD/CAE class systems to aerodynamic analysis of electric race cars

    NASA Astrophysics Data System (ADS)

    Grabowski, L.; Baier, A.; Buchacz, A.; Majzner, M.; Sobek, M.

    2015-11-01

    Aerodynamics is one of the most important factors which influence on every aspect of a design of a car and car driving parameters. The biggest influence aerodynamics has on design of a shape of a race car body, especially when the main objective of the race is the longest distance driven in period of time, which can not be achieved without low energy consumption and low drag of a car. Designing shape of the vehicle body that must generate the lowest possible drag force, without compromising the other parameters of the drive. In the article entitled „Application of CAD/CAE class systems to aerodynamic analysis of electric race cars” are being presented problems solved by computer analysis of cars aerodynamics and free form modelling. Analysis have been subjected to existing race car of a Silesian Greenpower Race Team. On a basis of results of analysis of existence of Kammback aerodynamic effect innovative car body were modeled. Afterwards aerodynamic analysis were performed to verify existence of aerodynamic effect for innovative shape and to recognize aerodynamics parameters of the shape. Analysis results in the values of coefficients and aerodynamic drag forces. The resulting drag forces Fx, drag coefficients Cx(Cd) and aerodynamic factors Cx*A allowed to compare all of the shapes to each other. Pressure distribution, air velocities and streams courses were useful in determining aerodynamic features of analyzed shape. For aerodynamic tests was used Ansys Fluent CFD software. In a paper the ways of surface modeling with usage of Realize Shape module and classic surface modeling were presented. For shapes modeling Siemens NX 9.0 software was used. Obtained results were used to estimation of existing shapes and to make appropriate conclusions.

  8. Functional cross-hemispheric shift between object-place paired associate memory and spatial memory in the human hippocampus.

    PubMed

    Lee, Choong-Hee; Ryu, Jungwon; Lee, Sang-Hun; Kim, Hakjin; Lee, Inah

    2016-08-01

    The hippocampus plays critical roles in both object-based event memory and spatial navigation, but it is largely unknown whether the left and right hippocampi play functionally equivalent roles in these cognitive domains. To examine the hemispheric symmetry of human hippocampal functions, we used an fMRI scanner to measure BOLD activity while subjects performed tasks requiring both object-based event memory and spatial navigation in a virtual environment. Specifically, the subjects were required to form object-place paired associate memory after visiting four buildings containing discrete objects in a virtual plus maze. The four buildings were visually identical, and the subjects used distal visual cues (i.e., scenes) to differentiate the buildings. During testing, the subjects were required to identify one of the buildings when cued with a previously associated object, and when shifted to a random place, the subject was expected to navigate to the previously chosen building. We observed that the BOLD activity foci changed from the left hippocampus to the right hippocampus as task demand changed from identifying a previously seen object (object-cueing period) to searching for its paired-associate place (object-cued place recognition period). Furthermore, the efficient retrieval of object-place paired associate memory (object-cued place recognition period) was correlated with the BOLD response of the left hippocampus, whereas the efficient retrieval of relatively pure spatial memory (spatial memory period) was correlated with the right hippocampal BOLD response. These findings suggest that the left and right hippocampi in humans might process qualitatively different information for remembering episodic events in space. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:27009679

  9. Parameter identification for nonlinear aerodynamic systems

    NASA Technical Reports Server (NTRS)

    Pearson, Allan E.

    1990-01-01

    Parameter identification for nonlinear aerodynamic systems is examined. It is presumed that the underlying model can be arranged into an input/output (I/O) differential operator equation of a generic form. The algorithm estimation is especially efficient since the equation error can be integrated exactly given any I/O pair to obtain an algebraic function of the parameters. The algorithm for parameter identification was extended to the order determination problem for linear differential system. The degeneracy in a least squares estimate caused by feedback was addressed. A method of frequency analysis for determining the transfer function G(j omega) from transient I/O data was formulated using complex valued Fourier based modulating functions in contrast with the trigonometric modulating functions for the parameter estimation problem. A simulation result of applying the algorithm is given under noise-free conditions for a system with a low pass transfer function.

  10. Functional Requirements: 2014 No Child Left Behind--Annual Measurable Achievement Objectives

    ERIC Educational Resources Information Center

    Minnesota Department of Education, 2014

    2014-01-01

    This document describes the Minnesota No Child Left Behind (NCLB) calculation as it relates to measuring Title III districts for Annual Measurable Achievement Objectives (AMAO). In 2012, a new assessment was used to measure language proficiency skills for English Learners. New AMAO targets were created, and new values for determining individual…

  11. [Influence of mental rotation of objects on psychophysiological functions of women].

    PubMed

    Chikina, L V; Fedorchuk, S V; Trushina, V A; Ianchuk, P I; Makarchuk, M Iu

    2012-01-01

    An integral part of activity of modern human beings is an involvement to work with the computer systems which, in turn, produces a nervous - emotional tension. Hence, a problem of control of the psychophysiological state of workmen with the purpose of health preservation and success of their activity and the problem of application of rehabilitational actions are actual. At present it is known that the efficiency of rehabilitational procedures rises following application of the complex of regenerative programs. Previously performed by us investigation showed that mental rotation is capable to compensate the consequences of a nervous - emotional tension. Therefore, in the present work we investigated how the complex of spatial tasks developed by us influences psychophysiological performances of tested women for which the psycho-emotional tension with the usage of computer technologies is more essential, and the procedure of mental rotation is more complex task for them, than for men. The complex of spatial tasks applied in the given work included: mental rotation of simple objects (letters and digits), mental rotation of complex objects (geometrical figures) and mental rotation of complex objects with the usage of a short-term memory. Execution of the complex of spatial tasks reduces the time of simple and complex sensomotor response, raises parameters of a short-term memory, brain work capacity and improves nervous processes. Collectively, mental rotation of objects can be recommended as a rehabilitational resource for compensation of consequences of any psycho-emotional strain, both for men, and for women. PMID:23233945

  12. Multi-objective optimization to predict muscle tensions in a pinch function using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Bensghaier, Amani; Romdhane, Lotfi; Benouezdou, Fethi

    2012-03-01

    This work is focused on the determination of the thumb and the index finger muscle tensions in a tip pinch task. A biomechanical model of the musculoskeletal system of the thumb and the index finger is developed. Due to the assumptions made in carrying out the biomechanical model, the formulated force analysis problem is indeterminate leading to an infinite number of solutions. Thus, constrained single and multi-objective optimization methodologies are used in order to explore the muscular redundancy and to predict optimal muscle tension distributions. Various models are investigated using the optimization process. The basic criteria to minimize are the sum of the muscle stresses, the sum of individual muscle tensions and the maximum muscle stress. The multi-objective optimization is solved using a Pareto genetic algorithm to obtain non-dominated solutions, defined as the set of optimal distributions of muscle tensions. The results show the advantage of the multi-objective formulation over the single objective one. The obtained solutions are compared to those available in the literature demonstrating the effectiveness of our approach in the analysis of the fingers musculoskeletal systems when predicting muscle tensions.

  13. Aerodynamic drag on intermodal railcars

    NASA Astrophysics Data System (ADS)

    Kinghorn, Philip; Maynes, Daniel

    2014-11-01

    The aerodynamic drag associated with transport of commodities by rail is becoming increasingly important as the cost of diesel fuel increases. This study aims to increase the efficiency of intermodal cargo trains by reducing the aerodynamic drag on the load carrying cars. For intermodal railcars a significant amount of aerodynamic drag is a result of the large distance between loads that often occurs and the resulting pressure drag resulting from the separated flow. In the present study aerodynamic drag data have been obtained through wind tunnel testing on 1/29 scale models to understand the savings that may be realized by judicious modification to the size of the intermodal containers. The experiments were performed in the BYU low speed wind tunnel and the test track utilizes two leading locomotives followed by a set of five articulated well cars with double stacked containers. The drag on a representative mid-train car is measured using an isolated load cell balance and the wind tunnel speed is varied from 20 to 100 mph. We characterize the effect that the gap distance between the containers and the container size has on the aerodynamic drag of this representative rail car and investigate methods to reduce the gap distance.

  14. Computations of Aerodynamic Performance Databases Using Output-Based Refinement

    NASA Technical Reports Server (NTRS)

    Nemec, Marian; Aftosmis, Michael J.

    2009-01-01

    Objectives: Handle complex geometry problems; Control discretization errors via solution-adaptive mesh refinement; Focus on aerodynamic databases of parametric and optimization studies: 1. Accuracy: satisfy prescribed error bounds 2. Robustness and speed: may require over 105 mesh generations 3. Automation: avoid user supervision Obtain "expert meshes" independent of user skill; and Run every case adaptively in production settings.

  15. Characterization of physical and aerodynamic properties of walnuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to study the physical and aerodynamic properties of freshly harvested walnuts. Measurements were carried out for three walnut varieties, Tulare, Howard and Chandler cultivated in California, USA. The nuts treated with and without Ethephon were collected from mechan...

  16. Feasibility study of a novel method for real-time aerodynamic coefficient estimation

    NASA Astrophysics Data System (ADS)

    Gurbacki, Phillip M.

    In this work, a feasibility study of a novel technique for the real-time identification of uncertain nonlinear aircraft aerodynamic coefficients has been conducted. The major objective of this paper is to investigate the feasibility of a system for parameter identification in a real-time flight environment. This system should be able to calculate aerodynamic coefficients and derivative information using typical pilot inputs while ensuring robust, stable, and rapid convergence. The parameter estimator investigated is based upon the nonlinear sliding mode control schema; one of the main advantages of the sliding mode estimator is the ability to guarantee a stable and robust convergence. Stable convergence is ensured by choosing a sliding surface and function that satisfies the Lyapunov stability criteria. After a proper sliding surface has been chosen, the nonlinear equations of motion for an F-16 aircraft are substituted into the sliding surface yielding an estimator capable of identifying a single aircraft parameter. Multiple sliding surfaces are then developed for each of the different flight parameters that will be identified. Sliding surfaces and parameter estimators have been developed and simulated for the pitching moment, lift force, and drag force coefficients of the F-16 aircraft. Comparing the estimated coefficients with the reference coefficients shows rapid and stable convergence for a variety of pilot inputs. Starting with simple doublet and sin wave commands, and followed by more complicated continuous pilot inputs, estimated aerodynamic coefficients have been shown to match the actual coefficients with a high degree of accuracy. This estimator is also shown to be superior to model reference or adaptive estimators, it is able to handle positive and negative estimated parameters and control inputs along with guaranteeing Lyapunov stability during convergence. Accurately estimating these aerodynamic parameters in real-time during a flight is essential

  17. Aerodynamic heating in hypersonic flows

    NASA Technical Reports Server (NTRS)

    Reddy, C. Subba

    1993-01-01

    Aerodynamic heating in hypersonic space vehicles is an important factor to be considered in their design. Therefore the designers of such vehicles need reliable heat transfer data in this respect for a successful design. Such data is usually produced by testing the models of hypersonic surfaces in wind tunnels. Most of the hypersonic test facilities at present are conventional blow-down tunnels whose run times are of the order of several seconds. The surface temperatures on such models are obtained using standard techniques such as thin-film resistance gages, thin-skin transient calorimeter gages and coaxial thermocouple or video acquisition systems such as phosphor thermography and infrared thermography. The data are usually reduced assuming that the model behaves like a semi-infinite solid (SIS) with constant properties and that heat transfer is by one-dimensional conduction only. This simplifying assumption may be valid in cases where models are thick, run-times short, and thermal diffusivities small. In many instances, however, when these conditions are not met, the assumption may lead to significant errors in the heat transfer results. The purpose of the present paper is to investigate this aspect. Specifically, the objectives are as follows: (1) to determine the limiting conditions under which a model can be considered a semi-infinite body; (2) to estimate the extent of errors involved in the reduction of the data if the models violate the assumption; and (3) to come up with correlation factors which when multiplied by the results obtained under the SIS assumption will provide the results under the actual conditions.

  18. Incidental and context-responsive activation of structure- and function-based action features during object identification.

    PubMed

    Lee, Chia-lin; Middleton, Erica; Mirman, Daniel; Kalénine, Solène; Buxbaum, Laurel J

    2013-02-01

    Previous studies suggest that action representations are activated during object processing, even when task-irrelevant. In addition, there is evidence that lexical-semantic context may affect such activation during object processing. Finally, prior work from our laboratory and others indicates that function-based ("use") and structure-based ("move") action subtypes may differ in their activation characteristics. Most studies assessing such effects, however, have required manual object-relevant motor responses, thereby plausibly influencing the activation of action representations. The present work uses eyetracking and a Visual World Paradigm task without object-relevant actions to assess the time course of activation of action representations, as well as their responsiveness to lexical-semantic context. In two experiments, participants heard a target word and selected its referent from an array of four objects. Gaze fixations on nontarget objects signal activation of features shared between targets and nontargets. The experiments assessed activation of structure-based (Experiment 1) or function-based (Experiment 2) distractors, using neutral sentences ("S/he saw the....") or sentences with a relevant action verb (Experiment 1: "S/he picked up the...."; Experiment 2: "S/he used the...."). We observed task-irrelevant activations of action information in both experiments. In neutral contexts, structure-based activation was relatively faster-rising but more transient than function-based activation. Additionally, action verb contexts reliably modified patterns of activation in both Experiments. These data provide fine-grained information about the dynamics of activation of function-based and structure-based actions in neutral and action-relevant contexts, in support of the "Two Action System" model of object and action processing (e.g., Buxbaum & Kalénine, 2010). PMID:22390294

  19. New technology in turbine aerodynamics.

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.; Moffitt, T. P.

    1972-01-01

    Cursory review of some recent work that has been done in turbine aerodynamic research. Topics discussed include the aerodynamic effect of turbine coolant, high work-factor (ratio of stage work to square of blade speed) turbines, and computer methods for turbine design and performance prediction. Experimental cooled-turbine aerodynamics programs using two-dimensional cascades, full annular cascades, and cold rotating turbine stage tests are discussed with some typical results presented. Analytically predicted results for cooled blade performance are compared to experimental results. The problems and some of the current programs associated with the use of very high work factors for fan-drive turbines of high-bypass-ratio engines are discussed. Computer programs have been developed for turbine design-point performance, off-design performance, supersonic blade profile design, and the calculation of channel velocities for subsonic and transonic flowfields. The use of these programs for the design and analysis of axial and radial turbines is discussed.

  20. Recent advances in computational aerodynamics

    NASA Astrophysics Data System (ADS)

    Agarwal, Ramesh K.; Desse, Jerry E.

    1991-04-01

    The current state of the art in computational aerodynamics is described. Recent advances in the discretization of surface geometry, grid generation, and flow simulation algorithms have led to flowfield predictions for increasingly complex and realistic configurations. As a result, computational aerodynamics is emerging as a crucial enabling technology for the development and design of flight vehicles. Examples illustrating the current capability for the prediction of aircraft, launch vehicle and helicopter flowfields are presented. Unfortunately, accurate modeling of turbulence remains a major difficulty in the analysis of viscosity-dominated flows. In the future inverse design methods, multidisciplinary design optimization methods, artificial intelligence technology and massively parallel computer technology will be incorporated into computational aerodynamics, opening up greater opportunities for improved product design at substantially reduced costs.

  1. Functional connectivity in the prefrontal cortex measured by near-infrared spectroscopy during ultrarapid object recognition

    NASA Astrophysics Data System (ADS)

    Medvedev, Andrei V.; Kainerstorfer, Jana M.; Borisov, Sergey V.; Vanmeter, John

    2011-01-01

    Near-infrared spectroscopy (NIRS) is a developing technology for low-cost noninvasive functional brain imaging. With multichannel optical instruments, it becomes possible to measure not only local changes in hemoglobin concentrations but also temporal correlations of those changes in different brain regions which gives an optical analog of functional connectivity traditionally measured by fMRI. We recorded hemodynamic activity during the Go-NoGo task from 11 right-handed subjects with probes placed bilaterally over prefrontal areas. Subjects were detecting animals as targets in natural scenes pressing a mouse button. Data were low-pass filtered <1 Hz and cardiac/respiration/superficial layers artifacts were removed using Independent Component Analysis. Fisher's transformed correlations of poststimulus responses (30 s) were averaged over groups of channels unilaterally in each hemisphere (intrahemispheric connectivity) and the corresponding channels between hemispheres (interhemispheric connectivity). The hemodynamic response showed task-related activation (an increase/decrease in oxygenated/deoxygenated hemoglobin, respectively) greater in the right versus left hemisphere. Intra- and interhemispheric functional connectivity was also significantly stronger during the task compared to baseline. Functional connectivity between the inferior and the middle frontal regions was significantly stronger in the right hemisphere. Our results demonstrate that optical methods can be used to detect transient changes in functional connectivity during rapid cognitive processes.

  2. Supersonic Aerodynamic Characteristics of Proposed Mars '07 Smart Lander Configurations

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Horvath, Thomas J.; Erickson, Gary E.; Green, Joseph M.

    2002-01-01

    Supersonic aerodynamic data were obtained for proposed Mars '07 Smart Lander configurations in NASA Langley Research Center's Unitary Plan Wind Tunnel. The primary objective of this test program was to assess the supersonic aerodynamic characteristics of the baseline Smart Lander configuration with and without fixed shelf/tab control surfaces. Data were obtained over a Mach number range of 2.3 to 4.5, at a free stream Reynolds Number of 1 x 10(exp 6) based on body diameter. All configurations were run at angles of attack from -5 to 20 degrees and angles of sideslip of -5 to 5 degrees. These results were complemented with computational fluid dynamic (CFD) predictions to enhance the understanding of experimentally observed aerodynamic trends. Inviscid and viscous full model CFD solutions compared well with experimental results for the baseline and 3 shelf/tab configurations. Over the range tested, Mach number effects were shown to be small on vehicle aerodynamic characteristics. Based on the results from 3 different shelf/tab configurations, a fixed control surface appears to be a feasible concept for meeting aerodynamic performance metrics necessary to satisfy mission requirements.

  3. Obtaining the Transfer Function of optical instruments using large calibrated reference objects.

    PubMed

    Henning, A J; Huntley, J M; Giusca, C L

    2015-06-29

    It has been suggested recently that the Transfer Function of instruments such as Coherence Scanning Interferometers could be measured via a single measurement of a large spherical artefact [Appl. Opt.53(8), 1554-1563 (2014)]. In the current paper we present analytical solutions for the Fourier transform of the 'foil' model used in this technique, which thus avoids the artefacts resulting from the numerical approach used earlier. The Fourier transform of a partial spherical shell is found to contain points of zero amplitude for spatial frequencies that lie within the Transfer Function. This implies that the Transfer Function is unmeasurable at these points when a single spherical artefact is used, in situations where the foil model is a valid representation of the physical system. We propose extensions to the method to address this issue. PMID:26191674

  4. 1999 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    Hahne, David E. (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1999 Aerodynamic Performance Technical Review on February 8-12, 1999 in Anaheim, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in the areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among die scientists and engineers working on HSCT aerodynamics. In particular, single and midpoint optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented, along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program. This Volume 2/Part 2 publication covers the tools and methods development session.

  5. 1998 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    McMillin, S. Naomi (Editor)

    1999-01-01

    NASA's High-Speed Research Program sponsored the 1998 Aerodynamic Performance Technical Review on February 9-13, in Los Angeles, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization), High-Lift, and Flight Controls. The review objectives were to (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientists and engineers working HSCT aerodynamics. In particular, single- and multi-point optimized HSCT configurations, HSCT high-lift system performance predictions, and HSCT simulation results were presented along with executive summaries for all the Aerodynamic Performance technology areas. The HSR Aerodynamic Performance Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration. Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas of the HSR Program.

  6. Aerodynamics Research Revolutionizes Truck Design

    NASA Technical Reports Server (NTRS)

    2008-01-01

    During the 1970s and 1980s, researchers at Dryden Flight Research Center conducted numerous tests to refine the shape of trucks to reduce aerodynamic drag and improved efficiency. During the 1980s and 1990s, a team based at Langley Research Center explored controlling drag and the flow of air around a moving body. Aeroserve Technologies Ltd., of Ottawa, Canada, with its subsidiary, Airtab LLC, in Loveland, Colorado, applied the research from Dryden and Langley to the development of the Airtab vortex generator. Airtabs create two counter-rotating vortices to reduce wind resistance and aerodynamic drag of trucks, trailers, recreational vehicles, and many other vehicles.

  7. Unsteady aerodynamic modeling and active aeroelastic control

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Unsteady aerodynamic modeling techniques are developed and applied to the study of active control of elastic vehicles. The problem of active control of a supercritical flutter mode poses a definite design goal stability, and is treated in detail. The transfer functions relating the arbitrary airfoil motions to the airloads are derived from the Laplace transforms of the linearized airload expressions for incompressible two dimensional flow. The transfer function relating the motions to the circulatory part of these loads is recognized as the Theodorsen function extended to complex values of reduced frequency, and is termed the generalized Theodorsen function. Inversion of the Laplace transforms yields exact transient airloads and airfoil motions. Exact root loci of aeroelastic modes are calculated, providing quantitative information regarding subcritical and supercritical flutter conditions.

  8. Self Instructional Manual for Tumor Registrars: Book 1, Objectives and Functions of a Tumor Registry.

    ERIC Educational Resources Information Center

    National Cancer Inst. (NIH), Bethesda, MD.

    The programed text is designed to provide tumor registrars with a means of learning the procedures for abstracting charts of cancer patients and for carrying out the other functions of a tumor registry. It was developed as an adjunct to on-the-job training for use without direct instructor supervision. Directions and suggestions for using the…

  9. Luminosity enhancement in relativistic jets and altered luminosity functions for beamed objects

    NASA Technical Reports Server (NTRS)

    Urry, C. M.; Shafer, R. A.

    1983-01-01

    Due to relativistic effects, the observed emission from relativistic jets is quite different from the rest frame emission. Systematic differences between the observed and intrinsic intensities of sources in which jet phenomena are occurring are discussed. Assuming that jets have a power law luminosity function of a slope B, the observed luminosity distribution as a function of the velocity of the jet, the spectral index of the rest frame emission, and the range of angles of the jets relative to our line of sight are calculated. The results is well-approximated by two power laws, the higher luminosity end having the original power law index X and the lower luminosity end having a flattened exponent independent of B and only slightly greater than 1. A model consisting of beamed emission from a jet and unbeamed emission from a stationary central component is investigated. The luminosity functions for these two-component sources are calculated for two ranges of angles. For sources in which beaming is important, the luminosity function is much flatter. Because of this, the relative numbers of ""beamed'' and ""unbeamed'' sources detected on the sky depend strongly on the luminosity at which the comparison is made.

  10. Understanding the Function of Visual Short-Term Memory: Transsaccadic Memory, Object Correspondence, and Gaze Correction

    ERIC Educational Resources Information Center

    Hollingworth, Andrew; Richard, Ashleigh M.; Luck, Steven J.

    2008-01-01

    Visual short-term memory (VSTM) has received intensive study over the past decade, with research focused on VSTM capacity and representational format. Yet, the function of VSTM in human cognition is not well understood. Here, the authors demonstrate that VSTM plays an important role in the control of saccadic eye movements. Intelligent human…

  11. Aerodynamics Of Missiles: Present And Future

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.

    1991-01-01

    Paper reviews variety of topics in aerodynamics of missiles. Describes recent developments and suggests areas in which future research fruitful. Emphasis on stability and control of tactical missiles. Aerodynamic problems discussed in general terms without reference to particular missiles.

  12. Application Program Interface for the Orion Aerodynamics Database

    NASA Technical Reports Server (NTRS)

    Robinson, Philip E.; Thompson, James

    2013-01-01

    The Application Programming Interface (API) for the Crew Exploration Vehicle (CEV) Aerodynamic Database has been developed to provide the developers of software an easily implemented, fully self-contained method of accessing the CEV Aerodynamic Database for use in their analysis and simulation tools. The API is programmed in C and provides a series of functions to interact with the database, such as initialization, selecting various options, and calculating the aerodynamic data. No special functions (file read/write, table lookup) are required on the host system other than those included with a standard ANSI C installation. It reads one or more files of aero data tables. Previous releases of aerodynamic databases for space vehicles have only included data tables and a document of the algorithm and equations to combine them for the total aerodynamic forces and moments. This process required each software tool to have a unique implementation of the database code. Errors or omissions in the documentation, or errors in the implementation, led to a lengthy and burdensome process of having to debug each instance of the code. Additionally, input file formats differ for each space vehicle simulation tool, requiring the aero database tables to be reformatted to meet the tool s input file structure requirements. Finally, the capabilities for built-in table lookup routines vary for each simulation tool. Implementation of a new database may require an update to and verification of the table lookup routines. This may be required if the number of dimensions of a data table exceeds the capability of the simulation tools built-in lookup routines. A single software solution was created to provide an aerodynamics software model that could be integrated into other simulation and analysis tools. The highly complex Orion aerodynamics model can then be quickly included in a wide variety of tools. The API code is written in ANSI C for ease of portability to a wide variety of systems. The

  13. Theoretical and Experimental Investigation of Random Gust Loads Part I : Aerodynamic Transfer Function of a Simple Wing Configuration in Incompressible Flow

    NASA Technical Reports Server (NTRS)

    Hakkinen, Raimo J; Richardson, A S , Jr

    1957-01-01

    Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

  14. FY2003 Annual Report: DOE Project on Heavy Vehicle Aerodynamic Drag

    SciTech Connect

    McCallen, R C; Salari, K; Ortega, J; DeChant, L J; Roy, C J; Payne, J J; Hassan, B; Pointer, W D; Browand, F; Hammache, M; Hsu, T; Ross, J; Satran, D; Heineck, J; Walker, S; Yaste, D; Englar, R; Leonard, A; Rubel, M; Chatelain, P

    2003-10-24

    Objective: {sm_bullet} Provide guidance to industry in the reduction of aerodynamic drag of heavy truck vehicles. {sm_bullet} Establish a database of experimental, computational, and conceptual design information, and demonstrate potential of new drag-reduction devices.

  15. Objective measures for predicting speech intelligibility in noisy conditions based on new band-importance functions

    PubMed Central

    Ma, Jianfen; Hu, Yi; Loizou, Philipos C.

    2009-01-01

    The articulation index (AI), speech-transmission index (STI), and coherence-based intelligibility metrics have been evaluated primarily in steady-state noisy conditions and have not been tested extensively in fluctuating noise conditions. The aim of the present work is to evaluate the performance of new speech-based STI measures, modified coherence-based measures, and AI-based measures operating on short-term (30 ms) intervals in realistic noisy conditions. Much emphasis is placed on the design of new band-importance weighting functions which can be used in situations wherein speech is corrupted by fluctuating maskers. The proposed measures were evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech (consonants and sentences) corrupted by four different maskers (car, babble, train, and street interferences). Of all the measures considered, the modified coherence-based measures and speech-based STI measures incorporating signal-specific band-importance functions yielded the highest correlations (r=0.89–0.94). The modified coherence measure, in particular, that only included vowel∕consonant transitions and weak consonant information yielded the highest correlation (r=0.94) with sentence recognition scores. The results from this study clearly suggest that the traditional AI and STI indices could benefit from the use of the proposed signal- and segment-dependent band-importance functions. PMID:19425678

  16. Objective evaluation of the relative modulation transfer function of densitometers for digitisation of electron micrographs.

    PubMed

    Roseman, A M; Neumann, K

    2003-08-01

    Digitisation of images recorded on film is a crucial part of data acquisition in electron microscopy, particularly for electron cryo-microscopy of biological specimens where the contrast and signal-to-noise ratio are low. A quantitative method to evaluate and compare the quality of densitometers, as measured by the modulation transfer function (MTF), is described here. The densitometer is modelled as a linear system, the output being the convolution of the input image and a point spread function. The MTF is the magnitude of the Fourier transform of the point spread function. The relative MTF describes the quality of signal transfer with spatial frequency. It is important that fine structural details in the micrograph are digitised with a high value for the MTF which does not vary with direction. A test pattern has been generated by projecting an electron image of a grid pattern onto film. The film is scanned and a computer program measures the intensities of the diffraction orders of the repeating pattern. Three different scanners are compared, one is a point scanner and the other two are line scanners. The test can be used to check if a scanner is set up optimally, and how it compares with another scanner. PMID:12672572

  17. Actin-based propulsion of functionalized hard versus fluid spherical objects

    NASA Astrophysics Data System (ADS)

    Delatour, Vincent; Shekhar, Shashank; Reymann, Anne-Cécile; Didry, Dominique; Diêp Lê, Kim Hô; Romet-Lemonne, Guillaume; Helfer, Emmanuèle; Carlier, Marie-France

    2008-02-01

    The directed polymerization of a branched actin network against a functionalized surface drives cell protrusions and organelle propulsion in living cells. Solid microspheres or giant unilamellar vesicles, functionalized with neural Wiskott Aldrich syndrome protein (N-WASP), initiate the formation of a branched actin array using actin-related protein 2/3 (Arp2/3) complex, when placed in a motility assay reconstituted with pure proteins. These systems are useful biomimetic models of actin-based propulsion that allow to address how the interplay between the physical properties of the functionalized surface and the dynamics of the actin cytoskeleton determines motile behavior. Both solid beads and deformable vesicles display either continuous or saltatory propulsive motions, which are analyzed comparatively; we show that the deformability of liposomes and the mobility of N-WASP at the lipid surface affect the dynamic and structural parameters of the actin meshwork. Our results indicate that beads and vesicles use different mechanisms to translate insertional polymerization of actin at their surface into directed movement: stress relaxation within the actin gel prevents the accumulation of filaments at the front of moving beads, while segregation of nucleators reduces actin polymerization at the front of moving vesicles.

  18. Langley Symposium on Aerodynamics, volume 1

    NASA Technical Reports Server (NTRS)

    Stack, Sharon H. (Compiler)

    1986-01-01

    The purpose of this work was to present current work and results of the Langley Aeronautics Directorate covering the areas of computational fluid dynamics, viscous flows, airfoil aerodynamics, propulsion integration, test techniques, and low-speed, high-speed, and transonic aerodynamics. The following sessions are included in this volume: theoretical aerodynamics, test techniques, fluid physics, and viscous drag reduction.

  19. Construction Solutions For Historical Object Foundations In The Context Of Changing Their Functional Use

    NASA Astrophysics Data System (ADS)

    Gwizdała, Kazimierz; Florkowska, Sylwia

    2015-12-01

    Properly executed renovation and adaptation of a grade listed property not only ensures its constructional safety, but may also highlight the object's historical value. Taking into consideration various factors, such as divergence of interests, or technical and legal determinants, it is safe to say that the renovation and adaptation of grade listed properties for new purposes is a complex process. The authors of the paper wish to discuss the problem of renovation based on selected properties, with special regard to constructional solutions for foundations. The presented examples will illustrate the issue of foundation enhancements resulting from the adaptation of buildings for new purposes. Through individual constructional solutions, such as jet grouting, it was possible to ensure the stability of degraded properties and safe transfer of increased values of usage load.

  20. Practical Study on HVAC Control Technology Based on the Learning Function and Optimum Multiple Objective Processes

    NASA Astrophysics Data System (ADS)

    Ueda, Haruka; Dazai, Ryota; Kaseda, Chosei; Ikaga, Toshiharu; Kato, Akihiro

    Demand among large office buildings for the energy-saving benefits of the HVAC (Heating, Ventilating and Air-Conditioning) System are increasing as more and more people become concerned with global environmental issues. However, immoderate measures taken in the interest of energy conservation may encroach on the thermal comfort and productivity level of office workers. Building management should satisfy both indoor thermal comfort and energy conservation while adapting to the many regulatory, social, climate, and other changes that occur during the lifespan of the building. This paper demonstrates how optimal control of the HVAC system, based on data modeling and the multi-objective optimal method, achieves an efficient equilibrium between thermal comfort and energy conservation.

  1. Objective sleep, a novel risk factor for alterations in kidney function: the CARDIA Study

    PubMed Central

    Petrov, Megan E.; Kim, Yongin; Lauderdale, Diane S.; Lewis, Cora E.; Reis, Jared P.; Carnethon, Mercedes R.; Knutson, Kristen L.; Glasser, Stephen P.

    2014-01-01

    Objective To determine the association between objectively measured sleep and 10-year changes in estimated glomerular filtration rate (eGFR). Methods From 2003 to 2005, an ancillary sleep study was conducted at the Chicago site of the Coronary Artery Disease in Young Adults (CARDIA) study. Community-based black and white adults (aged 32–51 years) wore a wrist actigraph up to six nights to record sleep duration and fragmentation. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI). Participants without history of cardiovascular or chronic kidney diseases, proteinuria, or hypertension at the 2000–2001 CARDIA examination were followed over 10 years (n = 463). eGFR was estimated from serum creatinine (eGFRCr) at the 2000–2001, 2005–2006, and 2010–2011 CARDIA examinations, whereas cystatin-C-estimated eGFR (eGFRCys) was measured at the 2000–2001 and 2005–2006 examinations. Generalized estimating equation regression and linear models estimated the associations of each sleep parameter with changes in eGFRCr and eGFRCys, controlling for cardiovascular and renal risk. Results Sleep parameters were not related to 5-year change in eGFRCys. However, each 1 h decrease in sleep duration was significantly associated with a 1.5 mL/min/1.73 m2 higher eGFRCr [95% confidence interval (CI), 0.2–2.7], and each one-point increase in PSQI was significantly associated with a 0.5 mL/min/1.73 m2 higher eGFRCr (95% CI, 0.04–0.9) over 10 years. Conclusion In this community-based sample, shorter sleep and poorer sleep quality were related to higher kidney filtration rates over 10 years. PMID:25037841

  2. Advanced Aerodynamic Design of Passive Porosity Control Effectors

    NASA Technical Reports Server (NTRS)

    Hunter, Craig A.; Viken, Sally A.; Wood, Richard M.; Bauer, Steven X. S.

    2001-01-01

    This paper describes aerodynamic design work aimed at developing a passive porosity control effector system for a generic tailless fighter aircraft. As part of this work, a computational design tool was developed and used to layout passive porosity effector systems for longitudinal and lateral-directional control at a low-speed, high angle of attack condition. Aerodynamic analysis was conducted using the NASA Langley computational fluid dynamics code USM3D, in conjunction with a newly formulated surface boundary condition for passive porosity. Results indicate that passive porosity effectors can provide maneuver control increments that equal and exceed those of conventional aerodynamic effectors for low-speed, high-alpha flight, with control levels that are a linear function of porous area. This work demonstrates the tremendous potential of passive porosity to yield simple control effector systems that have no external moving parts and will preserve an aircraft's fixed outer mold line.

  3. Atmospheric testing of wind turbine trailing edge aerodynamic brakes

    SciTech Connect

    Miller, L.S.; Migliore, P.G.; Quandt, G.A.

    1997-12-31

    An experimental investigation was conducted using an instrumented horizontal-axis wind turbine that incorporated variable span trailing-edge aerodynamic brakes. A primary goal was to directly compare study results with (infinite-span) wind tunnel data and to provide information on how to account for device span effects during turbine design or analysis. Comprehensive measurements were utilized to define effective changes in the aerodynamic coefficients, as a function of angle of attack and control deflection, for three device spans and configurations. Differences in the lift and drag behavior are most pronounced near stall and for device spans of less than 15%. Drag performance is affected only minimally (<70%) for 15% or larger span devices. Interestingly, aerodynamic controls with characteristic vents or openings appear most affected by span reductions and three-dimensional flow.

  4. Sensitivity analysis in computational aerodynamics

    NASA Technical Reports Server (NTRS)

    Bristow, D. R.

    1984-01-01

    Information on sensitivity analysis in computational aerodynamics is given in outline, graphical, and chart form. The prediction accuracy if the MCAERO program, a perturbation analysis method, is discussed. A procedure for calculating perturbation matrix, baseline wing paneling for perturbation analysis test cases and applications of an inviscid sensitivity matrix are among the topics covered.

  5. Semianalytic modeling of aerodynamic shapes

    NASA Technical Reports Server (NTRS)

    Barger, R. L.; Adams, M. S.

    1985-01-01

    Equations for the semianalytic representation of a class of surfaces that vary smoothly in cross-sectional shape are presented. Some methods of fitting together and superimposing such surfaces are described. A brief discussion is also included of the application of the theory in various contexts such as computerized lofting of aerodynamic surfaces and grid generation.

  6. Aerodynamic laboratory at Cuatro Vientos

    NASA Technical Reports Server (NTRS)

    JUBERA

    1922-01-01

    This report presents a listing of the many experiments in aerodynamics taking place at Cuatro Vientos. Some of the studies include: testing spheres, in order to determine coefficients; mechanical and chemical tests of materials; and various tests of propeller strength and flexibility.

  7. New technology in turbine aerodynamics

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.; Moffitt, T. P.

    1972-01-01

    A cursory review is presented of some of the recent work that has been done in turbine aerodynamic research at NASA-Lewis Research Center. Topics discussed include the aerodynamic effect of turbine coolant, high work-factor (ratio of stage work to square of blade speed) turbines, and computer methods for turbine design and performance prediction. An extensive bibliography is included. Experimental cooled-turbine aerodynamics programs using two-dimensional cascades, full annular cascades, and cold rotating turbine stage tests are discussed with some typical results presented. Analytically predicted results for cooled blade performance are compared to experimental results. The problems and some of the current programs associated with the use of very high work factors for fan-drive turbines of high-bypass-ratio engines are discussed. Turbines currently being investigated make use of advanced blading concepts designed to maintain high efficiency under conditions of high aerodynamic loading. Computer programs have been developed for turbine design-point performance, off-design performance, supersonic blade profile design, and the calculation of channel velocities for subsonic and transonic flow fields. The use of these programs for the design and analysis of axial and radial turbines is discussed.

  8. Dynamic Soaring: Aerodynamics for Albatrosses

    ERIC Educational Resources Information Center

    Denny, Mark

    2009-01-01

    Albatrosses have evolved to soar and glide efficiently. By maximizing their lift-to-drag ratio "L/D", albatrosses can gain energy from the wind and can travel long distances with little effort. We simplify the difficult aerodynamic equations of motion by assuming that albatrosses maintain a constant "L/D". Analytic solutions to the simplified…

  9. POEMS in Newton's Aerodynamic Frustum

    ERIC Educational Resources Information Center

    Sampedro, Jaime Cruz; Tetlalmatzi-Montiel, Margarita

    2010-01-01

    The golden mean is often naively seen as a sign of optimal beauty but rarely does it arise as the solution of a true optimization problem. In this article we present such a problem, demonstrating a close relationship between the golden mean and a special case of Newton's aerodynamical problem for the frustum of a cone. Then, we exhibit a parallel…

  10. Aerodynamic design via control theory

    NASA Technical Reports Server (NTRS)

    Jameson, Antony

    1988-01-01

    The question of how to modify aerodynamic design in order to improve performance is addressed. Representative examples are given to demonstrate the computational feasibility of using control theory for such a purpose. An introduction and historical survey of the subject is included.

  11. Shuttle reentry aerodynamic heating test

    NASA Technical Reports Server (NTRS)

    Pond, J. E.; Mccormick, P. O.; Smith, S. D.

    1971-01-01

    The research for determining the space shuttle aerothermal environment is reported. Brief summaries of the low Reynolds number windward side heating test, and the base and leeward heating and high Reynolds number heating test are included. Also discussed are streamline divergence and the resulting effect on aerodynamic heating, and a thermal analyzer program that is used in the Thermal Environment Optimization Program.

  12. Rotary wing aerodynamically generated noise

    NASA Technical Reports Server (NTRS)

    Schmitz, F. J.; Morse, H. A.

    1982-01-01

    The history and methodology of aerodynamic noise reduction in rotary wing aircraft are presented. Thickness noise during hover tests and blade vortex interaction noise are determined and predicted through the use of a variety of computer codes. The use of test facilities and scale models for data acquisition are discussed.

  13. Nostril Aerodynamics of Scenting Animals

    NASA Astrophysics Data System (ADS)

    Settles, G. S.

    1997-11-01

    Dogs and other scenting animals detect airborne odors with extraordinary sensitivity. Aerodynamic sampling plays a key role, but the literature on olfaction contains little on the external aerodynamics thereof. To shed some light on this, the airflows generated by a scenting dog were visualized using the schlieren technique. It was seen that the dog stops panting in order to scent, since panting produces a turbulent jet which disturbs scent-bearing air currents. Inspiratory airflow enters the nostrils from straight ahead, while expiration is directed to the sides of the nose and downward, as was found elsewhere in the case of rats and rabbits. The musculature and geometry of the dog's nose thus modulates the airflow during scenting. The aerodynamics of a nostril which must act reversibly as both inlet and outlet is briefly discussed. The eventual practical goal of this preliminary work is to achieve a level of understanding of the aerodynamics of canine olfaction sufficient for the design of a mimicking device. (Research supported by the DARPA Unexploded Ordnance Detection and Neutralization Program.)

  14. Objective improvement in renal function post-Dietl's crisis: Documented on renal dynamic scintigraphy.

    PubMed

    Parida, Girish Kumar; Tripathi, Madhavi; Kumar, Kunal; Damle, Nishikant

    2016-01-01

    Dietl's crisis is one of the treatable causes of intermittent abdominal pain. The pain is due to acute hydronephrosis that leads to stretching of the pelvis. The most common cause of this intermittent hydronephrosis is aberrant renal vessel at lower pole that causes pelvi-ureteric junction obstruction.(PUJO). High insertion of the ureter is one of the other rare causes. We present a case of 5-year-old boy with intermittent abdominal pain and distension with ultrasonography features of gross left hydronephrosis. Renal dynamic scan.(RDS) with ethylene dicysteine showed negligible functioning left kidney. On third follow-up day, the patient passed a lot of urine with decrease in abdominal pain and distension. Then, again the patient was sent to us 8.days after the first study for repeat RDS, which showed significant improvement in function and decreased in the size of left kidney though with persistent PUJO. On exploration high insertion of the ureter at pelvis was found to be the cause and was treated. PMID:27385903

  15. Objective improvement in renal function post-Dietl's crisis: Documented on renal dynamic scintigraphy

    PubMed Central

    Parida, Girish Kumar; Tripathi, Madhavi; Kumar, Kunal; Damle, Nishikant

    2016-01-01

    Dietl's crisis is one of the treatable causes of intermittent abdominal pain. The pain is due to acute hydronephrosis that leads to stretching of the pelvis. The most common cause of this intermittent hydronephrosis is aberrant renal vessel at lower pole that causes pelvi-ureteric junction obstruction.(PUJO). High insertion of the ureter is one of the other rare causes. We present a case of 5-year-old boy with intermittent abdominal pain and distension with ultrasonography features of gross left hydronephrosis. Renal dynamic scan.(RDS) with ethylene dicysteine showed negligible functioning left kidney. On third follow-up day, the patient passed a lot of urine with decrease in abdominal pain and distension. Then, again the patient was sent to us 8.days after the first study for repeat RDS, which showed significant improvement in function and decreased in the size of left kidney though with persistent PUJO. On exploration high insertion of the ureter at pelvis was found to be the cause and was treated. PMID:27385903

  16. Concentric versus eccentric isokinetic strengthening of the rotator cuff. Objective data versus functional test.

    PubMed

    Ellenbecker, T S; Davies, G J; Rowinski, M J

    1988-01-01

    Twenty-two male and female college varsity tennis players trained for 6 weeks, one group using eccentric isokinetic internal and external shoulder rotation, and the second group using concentric isokinetic internal and external shoulder rotation. Subjects pretested and posttested both concentrically and eccentrically, so that training overflow and specificity could be examined. Three maximally hit tennis serves made before and after training, which were analyzed by high speed cinematography to obtain ball velocity, served as a functional performance measurement. Statistical analysis of peak torque (newton meters) and peak torque to body weight ratio have revealed significant concentric strength gains (P less than 0.005) in the concentric as well as the eccentric training groups. Eccentric strength gains were demonstrated by the concentric training group at selected speeds (P less than 0.05 and P less than 0.005) but were not generated in the eccentric group at the P less than 0.05 significance level. Functional test analysis shows an increase in maximal serve velocity at a significance level of P less than 0.005 in the concentric training group, with no significant (P greater than 0.01) increases in the eccentric group. PMID:3344883

  17. Modeling the Launch Abort Vehicle's Subsonic Aerodynamics from Free Flight Testing

    NASA Technical Reports Server (NTRS)

    Hartman, Christopher L.

    2010-01-01

    An investigation into the aerodynamics of the Launch Abort Vehicle for NASA's Constellation Crew Launch Vehicle in the subsonic, incompressible flow regime was conducted in the NASA Langley 20-ft Vertical Spin Tunnel. Time histories of center of mass position and Euler Angles are captured using photogrammetry. Time histories of the wind tunnel's airspeed and dynamic pressure are recorded as well. The primary objective of the investigation is to determine models for the aerodynamic yaw and pitch moments that provide insight into the static and dynamic stability of the vehicle. System IDentification Programs for AirCraft (SIDPAC) is used to determine the aerodynamic model structure and estimate model parameters. Aerodynamic models for the aerodynamic body Y and Z force coefficients, and the pitching and yawing moment coefficients were identified.

  18. The DELTA MONSTER: An RPV designed to investigate the aerodynamics of a delta wing platform

    NASA Technical Reports Server (NTRS)

    Connolly, Kristen; Flynn, Mike; Gallagher, Randy; Greek, Chris; Kozlowski, Marc; Mcdonald, Brian; Mckenna, Matt; Sellar, Rich; Shearon, Andy

    1989-01-01

    The mission requirements for the performance of aerodynamic tests on a delta wind planform posed some problems, these include aerodynamic interference; structural support; data acquisition and transmission instrumentation; aircraft stability and control; and propulsion implementation. To eliminate the problems of wall interference, free stream turbulence, and the difficulty of achieving dynamic similarity between the test and actual flight aircraft that are associated with aerodynamic testing in wind tunnels, the concept of the remotely piloted vehicle which can perform a basic aerodynamic study on a delta wing was the main objective for the Green Mission - the Delta Monster. The basic aerodynamic studies were performed on a delta wing with a sweep angle greater than 45 degrees. These tests were performed at various angles of attack and Reynolds numbers. The delta wing was instrumented to determine the primary leading edge vortex formation and location, using pressure measurements and/or flow visualization. A data acquisition system was provided to collect all necessary data.

  19. Study of aerodynamic technology for VSTOL fighter/attack aircraft, phase 1

    NASA Technical Reports Server (NTRS)

    Driggers, H. H.

    1978-01-01

    A conceptual design study was performed of a vertical attitude takeoff and landing (VATOL) fighter/attack aircraft. The configuration has a close-coupled canard-delta wing, side two-dimensional ramp inlets, and two augmented turbofan engines with thrust vectoring capability. Performance and sensitivities to objective requirements were calculated. Aerodynamic characteristics were estimated based on contractor and NASA wind tunnel data. Computer simulations of VATOL transitions were performed. Successful transitions can be made, even with series post-stall instabilities, if reaction controls are properly phased. Principal aerodynamic uncertainties identified were post-stall aerodynamics, transonic aerodynamics with thrust vectoring and inlet performance in VATOL transition. A wind tunnel research program was recommended to resolve the aerodynamic uncertainties.

  20. Thioxanthone functionalized silver nanorods as smart photoinitiating assemblies to generate photopolymer/metal nano-objects.

    PubMed

    Niu, Songlin; Schneider, Raphaël; Vidal, Loïc; Balan, Lavinia

    2013-07-21

    Silver nanorods (AgNRs) with lengths in the 50-60 nm range were synthesized and functionalized with 2-(2-mercaptoethyl)thioxanthone (C2TX) to generate AgNR@C2TX nanoassemblies. When irradiated at 377 nm in the presence of a diacrylate monomer, these dispersed nanoassemblies initiate radical photopolymerization, indicating that the excited singlet to triplet intersystem crossing process of C2TX in the vicinity of AgNRs was favored while the fluorescence of C2TX was completely quenched at the surface of NRs. SEM and TEM images confirmed the formation of a AgNR-polymer nanocomposite and the homogeneous dispersion of AgNRs in the polymer film. Moreover, under specific experimental conditions allowing the spatial extent of the polymerization to be limited, polymer-capped AgNRs were obtained (polymer diameter of ca. 1 nm). PMID:23760523

  1. Objective Functional Assessment After a Head Injury Using Movement and Activity in Physical Space Scores: A Case Report

    PubMed Central

    Farnsworth, James L.; McElhiney, Danielle; David, Shannon; Sinha, Gaurav; Ragan, Brian G.

    2014-01-01

    Objective: To describe the potential benefit of using a global positioning system (GPS) and accelerometry as an objective functional-activity measure after concussion by creating Movement and Activity in Physical Space (MAPS) scores. Background: A 21-year-old female soccer player suffered a blow to the back of the head from an opponent's shoulder during an away match. No athletic trainer was present. She played the remainder of the match and reported to the athletic training facility the next day for evaluation. Differential Diagnosis: Concussion. Treatment: The athlete was removed from all athletic activities. Her symptoms were monitored based on the Zurich guidelines. She was also instructed to wear an accelerometer on her hip and to carry an on-person GPS receiver at all times for 10 days. Her total symptom scores for the 4 symptomatic days were 82, 39, 49, and 36. Her mean MAPS functional score for symptomatic days 3 through 5 was 900.9 and for asymptomatic days 6 through 11 was 2734.9. Uniqueness: We monitored the patient's function during the concussion-recovery process using an on-person GPS receiver and accelerometer to calculate personalized MAPS scores. This novel approach to measuring function after injury may provide a useful complementary tool to help with return-to-play decisions. Conclusions: An on-person GPS receiver and accelerometer were used to observe the patient's physical activity in a free-living environment, allowing for an objective measure of function during recovery. Her MAPS scores were low while she was symptomatic and increased as she became asymptomatic. We saw the expected inverse relationship between symptoms and function. In situations where accuracy of reported symptoms may be a concern, this measure may provide a way to verify the validity of, or raise doubts about, self-reported symptoms. PMID:24840582

  2. Aeroassist flight experiment aerodynamics and aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Brewer, Edwin B.

    1989-01-01

    The problem is to determine the transitional flow aerodynamics and aerothermodynamics, including the base flow characteristics, of the Aeroassist Flight Experiment (AFE). The justification for the computational fluid dynamic (CFD) Application stems from MSFC's system integration responsibility for the AFE. To insure that the AFE objectives are met, MSFC must understand the limitations and uncertainties of the design data. Perhaps the only method capable of handling the complex physics of the rarefied high energy AFE trajectory is Bird's Direct Simulation Monte Carlo (DSMC) technique. The 3-D code used in this analysis is applicable only to the AFE geometry. It uses the Variable Hard Sphere (VHS) collision model and five specie chemistry model available from Langley Research Center. The code is benchmarked against the AFE flight data and used as an Aeroassisted Space Transfer Vehicle (ASTV) design tool. The code is being used to understand the AFE flow field and verify or modify existing design data. Continued application to lower altitudes is testing the capability of the Numerical Aerodynamic Simulation Facility (NASF) to handle 3-D DSMC and its practicality as an ASTV/AFE design tool.

  3. Aerodynamics of Stardust Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Mitcheltree, R. A.; Wilmoth, R. G.; Cheatwood, F. M.; Brauckmann, G. J.; Greene, F. A.

    1997-01-01

    Successful return of interstellar dust and cometary material by the Stardust Sample Return Capsule requires an accurate description of the Earth entry vehicle's aerodynamics. This description must span the hypersonic-rarefied, hypersonic-continuum, supersonic, transonic, and subsonic flow regimes. Data from numerous sources are compiled to accomplish this objective. These include Direct Simulation Monte Carlo analyses, thermochemical nonequilibrium computational fluid dynamics, transonic computational fluid dynamics, existing wind tunnel data, and new wind tunnel data. Four observations are highlighted: 1) a static instability is revealed in the free-molecular and early transitional-flow regime due to aft location of the vehicle s center-of-gravity, 2) the aerodynamics across the hypersonic regime are compared with the Newtonian flow approximation and a correlation between the accuracy of the Newtonian flow assumption and the sonic line position is noted, 3) the primary effect of shape change due to ablation is shown to be a reduction in drag, and 4) a subsonic dynamic instability is revealed which will necessitate either a change in the vehicle s center-of-gravity location or the use of a stabilizing drogue parachute.

  4. Aerodynamic characteristics of popcorn ash particles

    SciTech Connect

    Cherkaduvasala, V.; Murphy, D.W.; Ban, H.; Harrison, K.E.; Monroe, L.S.

    2007-07-01

    Popcorn ash particles are fragments of sintered coal fly ash masses that resemble popcorn in low apparent density. They can travel with the flow in the furnace and settle on key places such as catalyst surfaces. Computational fluid dynamics (CFD) models are often used in the design process to prevent the carryover and settling of these particles on catalysts. Particle size, density, and drag coefficient are the most important aerodynamic parameters needed in CFD modeling of particle flow. The objective of this study was to experimentally determine particle size, shape, apparent density, and drag characteristics for popcorn ash particles from a coal-fired power plant. Particle size and shape were characterized by digital photography in three orthogonal directions and by computer image analysis. Particle apparent density was determined by volume and mass measurements. Particle terminal velocities in three directions were measured in water and each particle was also weighed in air and in water. The experimental data were analyzed and models were developed for equivalent sphere and equivalent ellipsoid with apparent density and drag coefficient distributions. The method developed in this study can be used to characterize the aerodynamic properties of popcorn-like particles.

  5. Atypical Functional Brain Activation During a Multiple Object Tracking Task in Girls With Turner Syndrome: Neurocorrelates of Reduced Spatiotemporal Resolution

    PubMed Central

    Beaton, Elliott A.; Stoddard, Joel; Lai, Song; Lackey, John; Shi, Jianrong; Ross, Judith L.; Simon, Tony J.

    2010-01-01

    Turner syndrome is associated with spatial and numerical cognitive impairments. We hypothesized that these nonverbal cognitive impairments result from limits in spatial and temporal processing, particularly as it affects attention. To examine spatiotemporal attention in girls with Turner syndrome versus typically developing controls, we used a multiple object tracking task during functional magnetic resonance (fMRI) imaging. Participants actively tracked a target among six distracters or passively viewed the animations. Neural activation in girls with Turner syndrome during object tracking overlapped with but was dissimilar to the canonical frontoparietal network evident in typically developing controls and included greater limbic activity. Task performance and atypical functional activation indicate anomalous development of cortical and subcortical temporal and spatial processing circuits in girls with Turner syndrome. PMID:20441384

  6. Rats' Visual-Spatial Working Memory: New Object Choice Accuracy as a Function of Number of Objects in the Study Array

    ERIC Educational Resources Information Center

    Cohen, Jerome; Han, Xue; Matei, Anca; Parameswaran, Varakini; Zuniga, Robert; Hlynka, Myron

    2010-01-01

    When rats had to find new (jackpot) objects for rewards from among previously sampled baited objects, increasing the number of objects in the sample (study) segment of a trial from 3 to 5 and then to 7 (Experiment 1) or from 3 to 6 and 9 (Experiments 2 and 3) or from 6 to 9 and 12 (Experiment 4) did not reduce rats' test segment performance.…

  7. Investigation of aerodynamic braking devices for wind turbine applications

    SciTech Connect

    Griffin, D.A.

    1997-04-01

    This report documents the selection and preliminary design of a new aerodynamic braking system for use on the stall-regulated AWT-26/27 wind turbines. The goal was to identify and design a configuration that offered improvements over the existing tip brake used by Advanced Wind Turbines, Inc. (AWT). Although the design objectives and approach of this report are specific to aerodynamic braking of AWT-26/27 turbines, many of the issues addressed in this work are applicable to a wider class of turbines. The performance trends and design choices presented in this report should be of general use to wind turbine designers who are considering alternative aerodynamic braking methods. A literature search was combined with preliminary work on device sizing, loads and mechanical design. Candidate configurations were assessed on their potential for benefits in the areas of cost, weight, aerodynamic noise, reliability and performance under icing conditions. As a result, two configurations were identified for further study: the {open_quotes}spoiler-flap{close_quotes} and the {open_quotes}flip-tip.{close_quotes} Wind tunnel experiments were conducted at Wichita State University to evaluate the performance of the candidate aerodynamic brakes on an airfoil section representative of the AWT-26/27 blades. The wind tunnel data were used to predict the braking effectiveness and deployment characteristics of the candidate devices for a wide range of design parameters. The evaluation was iterative, with mechanical design and structural analysis being conducted in parallel with the braking performance studies. The preliminary estimate of the spoiler-flap system cost was $150 less than the production AWT-26/27 tip vanes. This represents a reduction of approximately 5 % in the cost of the aerodynamic braking system. In view of the preliminary nature of the design, it would be prudent to plan for contingencies in both cost and weight.

  8. Development of an Objective Space Suit Mobility Performance Metric Using Metabolic Cost and Functional Tasks

    NASA Technical Reports Server (NTRS)

    McFarland, Shane M.; Norcross, Jason

    2016-01-01

    Existing methods for evaluating EVA suit performance and mobility have historically concentrated on isolated joint range of motion and torque. However, these techniques do little to evaluate how well a suited crewmember can actually perform during an EVA. An alternative method of characterizing suited mobility through measurement of metabolic cost to the wearer has been evaluated at Johnson Space Center over the past several years. The most recent study involved six test subjects completing multiple trials of various functional tasks in each of three different space suits; the results indicated it was often possible to discern between different suit designs on the basis of metabolic cost alone. However, other variables may have an effect on real-world suited performance; namely, completion time of the task, the gravity field in which the task is completed, etc. While previous results have analyzed completion time, metabolic cost, and metabolic cost normalized to system mass individually, it is desirable to develop a single metric comprising these (and potentially other) performance metrics. This paper outlines the background upon which this single-score metric is determined to be feasible, and initial efforts to develop such a metric. Forward work includes variable coefficient determination and verification of the metric through repeated testing.

  9. SUBSTELLAR OBJECTS IN NEARBY YOUNG CLUSTERS (SONYC): THE BOTTOM OF THE INITIAL MASS FUNCTION IN NGC 1333

    SciTech Connect

    Scholz, Alexander; Geers, Vincent; Jayawardhana, Ray; Fissel, Laura; Lee, Eve; Lafreniere, David; Tamura, Motohide

    2009-09-01

    SONYC-Substellar Objects in Nearby Young Clusters-is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. Here, we present the first results from SONYC observations of NGC 1333, a {approx}1 Myr old cluster in the Perseus star-forming complex. We have carried out extremely deep optical and near-infrared imaging in four bands (i', z', J, K) using Subaru Prime Focus Camera and Multi-Object InfraRed Camera and Spectrograph (MOIRCS) instruments at the Subaru telescope. The survey covers 0.25 deg{sup 2} and reaches completeness limits of 24.7 mag in the i' band and 20.8 mag in the J band. We select 196 candidates with colors as expected for young, very low mass objects. Follow-up multi-object spectroscopy with MOIRCS is presented for 53 objects. We confirm 19 objects as likely brown dwarfs (BDs) in NGC 1333, seven of them previously known. Nine additional objects are classified as possible stellar cluster members, likely with early to mid M spectral types. The confirmed objects are strongly clustered around the peak in the gas distribution and the core of the cluster of known stellar members. For 11 of them, we confirm the presence of disks based on Spitzer/Infrared Array Camera photometry. The effective temperatures for the BD sample range from 2500 K to 3000 K, which translates to masses of {approx}0.015-0.1 M{sub sun}, based on model evolutionary tracks. For comparison, the completeness limit of our survey translates to mass limits of 0.004 M{sub sun} for A{sub V} {approx}< 5 mag or 0.008 M{sub sun} for A{sub V} {approx}< 10 mag. Compared with other star-forming regions, NGC 1333 shows an overabundance of BDs relative to low-mass stars, by a factor of 2-5. On the other hand, NGC 1333 has a deficit of planetary-mass objects: based on the surveys in {sigma} Orionis, the Orion Nebula Cluster and Chamaeleon I, the expected number of planetary-mass objects in NGC

  10. Aerodynamics of a linear oscillating cascade

    NASA Technical Reports Server (NTRS)

    Buffum, Daniel H.; Fleeter, Sanford

    1990-01-01

    The steady and unsteady aerodynamics of a linear oscillating cascade are investigated using experimental and computational methods. Experiments are performed to quantify the torsion mode oscillating cascade aerodynamics of the NASA Lewis Transonic Oscillating Cascade for subsonic inlet flowfields using two methods: simultaneous oscillation of all the cascaded airfoils at various values of interblade phase angle, and the unsteady aerodynamic influence coefficient technique. Analysis of these data and correlation with classical linearized unsteady aerodynamic analysis predictions indicate that the wind tunnel walls enclosing the cascade have, in some cases, a detrimental effect on the cascade unsteady aerodynamics. An Euler code for oscillating cascade aerodynamics is modified to incorporate improved upstream and downstream boundary conditions and also the unsteady aerodynamic influence coefficient technique. The new boundary conditions are shown to improve the unsteady aerodynamic influence coefficient technique. The new boundary conditions are shown to improve the unsteady aerodynamic predictions of the code, and the computational unsteady aerodynamic influence coefficient technique is shown to be a viable alternative for calculation of oscillating cascade aerodynamics.

  11. Interdisciplinary optimization combining electromagnetic and aerodynamic methods

    NASA Astrophysics Data System (ADS)

    Sullivan, Anders James

    The design of missile body shapes often requires a compromise between aero-dynamic and electromagnetic performance goals. In general, the missile shape producing the lowest radar signature will be different from the preferred aero-dynamic shape. Interdisciplinary shape optimization is utilized to combine multiple disciplines to determine the best possible shape for a hybrid aerodynamic-electromagnetic problem. A composite missile body consisting of an axisymmetric body of revolution (BOR) and two thin flat plate attachments is considered. The goal is to minimize the drag and backscatter associated with this composite shape. The body is assumed to be perfectly conducting, and flying at zero degrees angle of attack. The variable nose shape serves as the optimization design parameter. To characterize the system performance, a cost function is defined which is comprised of weighted values of the drag and backscatter. To solve the electromagnetic problem, methods to treat electrically large complex bodies are investigated. Hybrid methods which combine the method of moments (MoM) with physical optics (PO) are developed to calculate the scattering from simple two-dimensional bodies. A surface-wave hybrid approach is shown to effectively approximate the traveling wave currents on the smooth interior portions of a BOR. Asymptotic methods are used to solve the resulting integral equations more efficiently. The hybrid methods are shown to produce MoM-quality results, while requiring less computational resources. To solve the composite body problem, an iterative technique is developed that preserves the simplicity of the original BOR scheme. In this formulation, the current over each part of the composite body is solved independently. The results from one part of the body are used to update the fields incident on the other part of the body. This procedure is repeated until the solution converges. To solve the aerodynamic problem, slender body theory is used to calculate the

  12. Application of Approximate Unsteady Aerodynamics for Flutter Analysis

    NASA Technical Reports Server (NTRS)

    Pak, Chan-gi; Li, Wesley W.

    2010-01-01

    A technique for approximating the modal aerodynamic influence coefficient (AIC) matrices by using basis functions has been developed. A process for using the resulting approximated modal AIC matrix in aeroelastic analysis has also been developed. The method requires the unsteady aerodynamics in frequency domain, and this methodology can be applied to the unsteady subsonic, transonic, and supersonic aerodynamics. The flutter solution can be found by the classic methods, such as rational function approximation, k, p-k, p, root locus et cetera. The unsteady aeroelastic analysis using unsteady subsonic aerodynamic approximation is demonstrated herein. The technique presented is shown to offer consistent flutter speed prediction on an aerostructures test wing (ATW) 2 and a hybrid wing body (HWB) type of vehicle configuration with negligible loss in precision. This method computes AICs that are functions of the changing parameters being studied and are generated within minutes of CPU time instead of hours. These results may have practical application in parametric flutter analyses as well as more efficient multidisciplinary design and optimization studies.

  13. AERODYNAMIC AND BLADING DESIGN OF MULTISTAGE AXIAL FLOW COMPRESSORS

    NASA Technical Reports Server (NTRS)

    Crouse, J. E.

    1994-01-01

    The axial-flow compressor is used for aircraft engines because it has distinct configuration and performance advantages over other compressor types. However, good potential performance is not easily obtained. The designer must be able to model the actual flows well enough to adequately predict aerodynamic performance. This computer program has been developed for computing the aerodynamic design of a multistage axial-flow compressor and, if desired, the associated blading geometry input for internal flow analysis. The aerodynamic solution gives velocity diagrams on selected streamlines of revolution at the blade row edges. The program yields aerodynamic and blading design results that can be directly used by flow and mechanical analysis codes. Two such codes are TSONIC, a blade-to-blade channel flow analysis code (COSMIC program LEW-10977), and MERIDL, a more detailed hub-to-shroud flow analysis code (COSMIC program LEW-12966). The aerodynamic and blading design program can reduce the time and effort required to obtain acceptable multistage axial-flow compressor configurations by generating good initial solutions and by being compatible with available analysis codes. The aerodynamic solution assumes steady, axisymmetric flow so that the problem is reduced to solving the two-dimensional flow field in the meridional plane. The streamline curvature method is used for the iterative aerodynamic solution at stations outside of the blade rows. If a blade design is desired, the blade elements are defined and stacked within the aerodynamic solution iteration. The blade element inlet and outlet angles are established by empirical incidence and deviation angles to the relative flow angles of the velocity diagrams. The blade element centerline is composed of two segments tangentially joined at a transition point. The local blade angle variation of each element can be specified as a fourth-degree polynomial function of path distance. Blade element thickness can also be specified

  14. Fully unsteady subsonic and supersonic potential aerodynamics for complex aircraft configurations with applications to flutter

    NASA Technical Reports Server (NTRS)

    Tseng, K.; Morino, L.

    1975-01-01

    A general formulation is presented for the analysis of steady and unsteady, subsonic and supersonic aerodynamics for complex aircraft configurations. The theoretical formulation, the numerical procedure, the description of the program SOUSSA (steady, oscillatory and unsteady, subsonic and supersonic aerodynamics) and numerical results are included. In particular, generalized forces for fully unsteady (complex frequency) aerodynamics for a wing-body configuration, AGARD wing-tail interference in both subsonic and supersonic flows as well as flutter analysis results are included. The theoretical formulation is based upon an integral equation, which includes completely arbitrary motion. Steady and oscillatory aerodynamic flows are considered. Here small-amplitude, fully transient response in the time domain is considered. This yields the aerodynamic transfer function (Laplace transform of the fully unsteady operator) for frequency domain analysis. This is particularly convenient for the linear systems analysis of the whole aircraft.

  15. The interference aerodynamics caused by the wing elasticity during store separation

    NASA Astrophysics Data System (ADS)

    Lei, Yang; Zheng-yin, Ye

    2016-04-01

    Air-launch-to-orbit is the technology that has stores carried aloft and launched the store from the plane to the orbit. The separation between the aircraft and store is one of the most important and difficult phases in air-launch-to-orbit technology. There exists strong aerodynamic interference between the aircraft and the store in store separation. When the aspect ratio of the aircraft is large, the elastic deformations of the wing must be considered. The main purpose of this article is to study the influence of the interference aerodynamics caused by the elastic deformations of the wing to the unsteady aerodynamics of the store. By solving the coupled functions of unsteady Navier-Stokes equations, six degrees of freedom dynamic equations and structural dynamic equations simultaneously, the store separation with the elastic deformation of the aircraft considered is simulated numerically. And the interactive aerodynamic forces are analyzed. The study shows that the interference aerodynamics is obvious at earlier time during the separation, and the dominant frequency of the elastic wing determines the aerodynamic forces frequencies of the store. Because of the effect of the interference aerodynamics, the roll angle response and pitch angle response increase. When the store is mounted under the wingtip, the additional aerodynamics caused by the wingtip vortex is obvious, which accelerate the divergence of the lateral force and the lateral-directional attitude angle of the store. This study supports some beneficial conclusions to the engineering application of the air-launch-to-orbit.

  16. Control of helicopter rotorblade aerodynamics

    NASA Technical Reports Server (NTRS)

    Fabunmi, James A.

    1991-01-01

    The results of a feasibility study of a method for controlling the aerodynamics of helicopter rotorblades using stacks of piezoelectric ceramic plates are presented. A resonant mechanism is proposed for the amplification of the displacements produced by the stack. This motion is then converted into linear displacement for the actuation of the servoflap of the blades. A design which emulates the actuation of the servoflap on the Kaman SH-2F is used to demonstrate the fact that such a system can be designed to produce the necessary forces and velocities needed to control the aerodynamics of the rotorblades of such a helicopter. Estimates of the electrical power requirements are also presented. A Small Business Innovation Research (SBIR) Phase 2 Program is suggested, whereby a bench-top prototype of the device can be built and tested. A collaborative effort between AEDAR Corporation and Kaman Aerospace Corporation is anticipated for future effort on this project.

  17. Computer Simulation of Aircraft Aerodynamics

    NASA Technical Reports Server (NTRS)

    Inouye, Mamoru

    1989-01-01

    The role of Ames Research Center in conducting basic aerodynamics research through computer simulations is described. The computer facilities, including supercomputers and peripheral equipment that represent the state of the art, are described. The methodology of computational fluid dynamics is explained briefly. Fundamental studies of turbulence and transition are being pursued to understand these phenomena and to develop models that can be used in the solution of the Reynolds-averaged Navier-Stokes equations. Four applications of computer simulations for aerodynamics problems are described: subsonic flow around a fuselage at high angle of attack, subsonic flow through a turbine stator-rotor stage, transonic flow around a flexible swept wing, and transonic flow around a wing-body configuration that includes an inlet and a tail.

  18. Viking entry aerodynamics and heating

    NASA Technical Reports Server (NTRS)

    Polutchko, R. J.

    1974-01-01

    The characteristics of the Mars entry including the mission sequence of events and associated spacecraft weights are described along with the Viking spacecraft. Test data are presented for the aerodynamic characteristics of the entry vehicle showing trimmed alpha, drag coefficient, and trimmed lift to drag ratio versus Mach number; the damping characteristics of the entry configuration; the angle of attack time history of Viking entries; stagnation heating and pressure time histories; and the aeroshell heating distribution as obtained in tests run in a shock tunnel for various gases. Flight tests which demonstrate the aerodynamic separation of the full-scale aeroshell and the flying qualities of the entry configuration in an uncontrolled mode are documented. Design values selected for the heat protection system based on the test data and analysis performed are presented.

  19. Landscape object-based analysis of wetland plant functional types: the effects of spatial scale, vegetation classes and classifier methods

    NASA Astrophysics Data System (ADS)

    Dronova, I.; Gong, P.; Wang, L.; Clinton, N.; Fu, W.; Qi, S.

    2011-12-01

    Remote sensing-based vegetation classifications representing plant function such as photosynthesis and productivity are challenging in wetlands with complex cover and difficult field access. Recent advances in object-based image analysis (OBIA) and machine-learning algorithms offer new classification tools; however, few comparisons of different algorithms and spatial scales have been discussed to date. We applied OBIA to delineate wetland plant functional types (PFTs) for Poyang Lake, the largest freshwater lake in China and Ramsar wetland conservation site, from 30-m Landsat TM scene at the peak of spring growing season. We targeted major PFTs (C3 grasses, C3 forbs and different types of C4 grasses and aquatic vegetation) that are both key players in system's biogeochemical cycles and critical providers of waterbird habitat. Classification results were compared among: a) several object segmentation scales (with average object sizes 900-9000 m2); b) several families of statistical classifiers (including Bayesian, Logistic, Neural Network, Decision Trees and Support Vector Machines) and c) two hierarchical levels of vegetation classification, a generalized 3-class set and more detailed 6-class set. We found that classification benefited from object-based approach which allowed including object shape, texture and context descriptors in classification. While a number of classifiers achieved high accuracy at the finest pixel-equivalent segmentation scale, the highest accuracies and best agreement among algorithms occurred at coarser object scales. No single classifier was consistently superior across all scales, although selected algorithms of Neural Network, Logistic and K-Nearest Neighbors families frequently provided the best discrimination of classes at different scales. The choice of vegetation categories also affected classification accuracy. The 6-class set allowed for higher individual class accuracies but lower overall accuracies than the 3-class set because

  20. Aerodynamic instability: A case history

    NASA Technical Reports Server (NTRS)

    Eisenmann, R. C.

    1985-01-01

    The identification, diagnosis, and final correction of complex machinery malfunctions typically require the correlation of many parameters such as mechanical construction, process influence, maintenance history, and vibration response characteristics. The progression is reviewed of field testing, diagnosis, and final correction of a specific machinery instability problem. The case history presented addresses a unique low frequency instability problem on a high pressure barrel compressor. The malfunction was eventually diagnosed as a fluidic mechanism that manifested as an aerodynamic disturbance to the rotor assembly.

  1. Aerodynamics of the Viggen 37 aircraft. Part 1: General characteristics at low speed

    NASA Technical Reports Server (NTRS)

    Karling, K.

    1986-01-01

    A description of the aerodynamics of the Viggen 37 and its performances, especially at low speeds is presented. The aerodynamic requirements for the design of the Viggen 37 aircraft are given, including the basic design, performance requirement, and aerodynamic characteristics, static and dynamic load test results and flight test results. The Viggen 37 aircraft is designed to be used for air attack, surveillance, pursuit, and training applications. It is shown that this aircraft is suitable for short runways, and has good maneuvering, acceleration, and climbing characteristics. The design objectives for this aircraft were met by utilizing the effect produced by the interference between two triangular wings, positioned in tandem.

  2. Applied aerodynamics: Challenges and expectations

    NASA Technical Reports Server (NTRS)

    Peterson, Victor L.; Smith, Charles A.

    1993-01-01

    Aerospace is the leading positive contributor to this country's balance of trade, derived largely from the sale of U.S. commercial aircraft around the world. This powerfully favorable economic situation is being threatened in two ways: (1) the U.S. portion of the commercial transport market is decreasing, even though the worldwide market is projected to increase substantially; and (2) expenditures are decreasing for military aircraft, which often serve as proving grounds for advanced aircraft technology. To retain a major share of the world market for commercial aircraft and continue to provide military aircraft with unsurpassed performance, the U.S. aerospace industry faces many technological challenges. The field of applied aerodynamics is necessarily a major contributor to efforts aimed at meeting these technological challenges. A number of emerging research results that will provide new opportunities for applied aerodynamicists are discussed. Some of these have great potential for maintaining the high value of contributions from applied aerodynamics in the relatively near future. Over time, however, the value of these contributions will diminish greatly unless substantial investments continue to be made in basic and applied research efforts. The focus: to increase understanding of fluid dynamic phenomena, identify new aerodynamic concepts, and provide validated advanced technology for future aircraft.

  3. X-34 Vehicle Aerodynamic Characteristics

    NASA Technical Reports Server (NTRS)

    Brauckmann, Gregory J.

    1998-01-01

    The X-34, being designed and built by the Orbital Sciences Corporation, is an unmanned sub-orbital vehicle designed to be used as a flying test bed to demonstrate key vehicle and operational technologies applicable to future reusable launch vehicles. The X-34 will be air-launched from an L-1011 carrier aircraft at approximately Mach 0.7 and 38,000 feet altitude, where an onboard engine will accelerate the vehicle to speeds above Mach 7 and altitudes to 250,000 feet. An unpowered entry will follow, including an autonomous landing. The X-34 will demonstrate the ability to fly through inclement weather, land horizontally at a designated site, and have a rapid turn-around capability. A series of wind tunnel tests on scaled models was conducted in four facilities at the NASA Langley Research Center to determine the aerodynamic characteristics of the X-34. Analysis of these test results revealed that longitudinal trim could be achieved throughout the design trajectory. The maximum elevon deflection required to trim was only half of that available, leaving a margin for gust alleviation and aerodynamic coefficient uncertainty. Directional control can be achieved aerodynamically except at combined high Mach numbers and high angles of attack, where reaction control jets must be used. The X-34 landing speed, between 184 and 206 knots, is within the capabilities of the gear and tires, and the vehicle has sufficient rudder authority to control the required 30-knot crosswind.

  4. Motor Skills and Exercise Capacity Are Associated with Objective Measures of Cognitive Functions and Academic Performance in Preadolescent Children

    PubMed Central

    Thomas, Richard; Larsen, Malte Nejst; Dahn, Ida Marie; Andersen, Josefine Needham; Krause-Jensen, Matilde; Korup, Vibeke; Nielsen, Claus Malta; Wienecke, Jacob; Ritz, Christian; Krustrup, Peter; Lundbye-Jensen, Jesper

    2016-01-01

    Objective To investigate associations between motor skills, exercise capacity and cognitive functions, and evaluate how they correlate to academic performance in mathematics and reading comprehension using standardised, objective tests. Methods This cross-sectional study included 423 Danish children (age: 9.29±0.35 years, 209 girls). Fine and gross motor skills were evaluated in a visuomotor accuracy-tracking task, and a whole-body coordination task, respectively. Exercise capacity was estimated from the Yo-Yo intermittent recovery level 1 children's test (YYIR1C). Selected tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were used to assess different domains of cognitive functions, including sustained attention, spatial working memory, episodic and semantic memory, and processing speed. Linear mixed-effects models were used to investigate associations between these measures and the relationship with standard tests of academic performance in mathematics and reading comprehension. Results Both fine and gross motor skills were associated with better performance in all five tested cognitive domains (all P<0.001), whereas exercise capacity was only associated with better sustained attention (P<0.046) and spatial working memory (P<0.038). Fine and gross motor skills (all P<0.001), exercise capacity and cognitive functions such as working memory, episodic memory, sustained attention and processing speed were all associated with better performance in mathematics and reading comprehension. Conclusions The data demonstrate that fine and gross motor skills are positively correlated with several aspects of cognitive functions and with academic performance in both mathematics and reading comprehension. Moreover, exercise capacity was associated with academic performance and performance in some cognitive domains. Future interventions should investigate associations between changes in motor skills, exercise capacity, cognitive functions, and academic

  5. SU-F-BRD-01: A Logistic Regression Model to Predict Objective Function Weights in Prostate Cancer IMRT

    SciTech Connect

    Boutilier, J; Chan, T; Lee, T; Craig, T; Sharpe, M

    2014-06-15

    Purpose: To develop a statistical model that predicts optimization objective function weights from patient geometry for intensity-modulation radiotherapy (IMRT) of prostate cancer. Methods: A previously developed inverse optimization method (IOM) is applied retrospectively to determine optimal weights for 51 treated patients. We use an overlap volume ratio (OVR) of bladder and rectum for different PTV expansions in order to quantify patient geometry in explanatory variables. Using the optimal weights as ground truth, we develop and train a logistic regression (LR) model to predict the rectum weight and thus the bladder weight. Post hoc, we fix the weights of the left femoral head, right femoral head, and an artificial structure that encourages conformity to the population average while normalizing the bladder and rectum weights accordingly. The population average of objective function weights is used for comparison. Results: The OVR at 0.7cm was found to be the most predictive of the rectum weights. The LR model performance is statistically significant when compared to the population average over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and mean voxel dose to the bladder, rectum, CTV, and PTV. On average, the LR model predicted bladder and rectum weights that are both 63% closer to the optimal weights compared to the population average. The treatment plans resulting from the LR weights have, on average, a rectum V70Gy that is 35% closer to the clinical plan and a bladder V70Gy that is 43% closer. Similar results are seen for bladder V54Gy and rectum V54Gy. Conclusion: Statistical modelling from patient anatomy can be used to determine objective function weights in IMRT for prostate cancer. Our method allows the treatment planners to begin the personalization process from an informed starting point, which may lead to more consistent clinical plans and reduce overall planning time.

  6. The origins of metamodality in visual object area LO: Bodily topographical biases and increased functional connectivity to S1

    PubMed Central

    Tal, Zohar; Geva, Ran; Amedi, Amir

    2016-01-01

    Recent evidence from blind participants suggests that visual areas are task-oriented and sensory modality input independent rather than sensory-specific to vision. Specifically, visual areas are thought to retain their functional selectivity when using non-visual inputs (touch or sound) even without having any visual experience. However, this theory is still controversial since it is not clear whether this also characterizes the sighted brain, and whether the reported results in the sighted reflect basic fundamental a-modal processes or are an epiphenomenon to a large extent. In the current study, we addressed these questions using a series of fMRI experiments aimed to explore visual cortex responses to passive touch on various body parts and the coupling between the parietal and visual cortices as manifested by functional connectivity. We show that passive touch robustly activated the object selective parts of the lateral–occipital (LO) cortex while deactivating almost all other occipital–retinotopic-areas. Furthermore, passive touch responses in the visual cortex were specific to hand and upper trunk stimulations. Psychophysiological interaction (PPI) analysis suggests that LO is functionally connected to the hand area in the primary somatosensory homunculus (S1), during hand and shoulder stimulations but not to any of the other body parts. We suggest that LO is a fundamental hub that serves as a node between visual-object selective areas and S1 hand representation, probably due to the critical evolutionary role of touch in object recognition and manipulation. These results might also point to a more general principle suggesting that recruitment or deactivation of the visual cortex by other sensory input depends on the ecological relevance of the information conveyed by this input to the task/computations carried out by each area or network. This is likely to rely on the unique and differential pattern of connectivity for each visual area with the rest of the

  7. The origins of metamodality in visual object area LO: Bodily topographical biases and increased functional connectivity to S1.

    PubMed

    Tal, Zohar; Geva, Ran; Amedi, Amir

    2016-02-15

    Recent evidence from blind participants suggests that visual areas are task-oriented and sensory modality input independent rather than sensory-specific to vision. Specifically, visual areas are thought to retain their functional selectivity when using non-visual inputs (touch or sound) even without having any visual experience. However, this theory is still controversial since it is not clear whether this also characterizes the sighted brain, and whether the reported results in the sighted reflect basic fundamental a-modal processes or are an epiphenomenon to a large extent. In the current study, we addressed these questions using a series of fMRI experiments aimed to explore visual cortex responses to passive touch on various body parts and the coupling between the parietal and visual cortices as manifested by functional connectivity. We show that passive touch robustly activated the object selective parts of the lateral-occipital (LO) cortex while deactivating almost all other occipital-retinotopic-areas. Furthermore, passive touch responses in the visual cortex were specific to hand and upper trunk stimulations. Psychophysiological interaction (PPI) analysis suggests that LO is functionally connected to the hand area in the primary somatosensory homunculus (S1), during hand and shoulder stimulations but not to any of the other body parts. We suggest that LO is a fundamental hub that serves as a node between visual-object selective areas and S1 hand representation, probably due to the critical evolutionary role of touch in object recognition and manipulation. These results might also point to a more general principle suggesting that recruitment or deactivation of the visual cortex by other sensory input depends on the ecological relevance of the information conveyed by this input to the task/computations carried out by each area or network. This is likely to rely on the unique and differential pattern of connectivity for each visual area with the rest of the

  8. Object Oriented Learning Objects

    ERIC Educational Resources Information Center

    Morris, Ed

    2005-01-01

    We apply the object oriented software engineering (OOSE) design methodology for software objects (SOs) to learning objects (LOs). OOSE extends and refines design principles for authoring dynamic reusable LOs. Our learning object class (LOC) is a template from which individualised LOs can be dynamically created for, or by, students. The properties…

  9. Computing Molecular Signatures as Optima of a Bi-Objective Function: Method and Application to Prediction in Oncogenomics

    PubMed Central

    Gardeux, Vincent; Chelouah, Rachid; Wanderley, Maria F Barbosa; Siarry, Patrick; Braga, Antônio P; Reyal, Fabien; Rouzier, Roman; Pusztai, Lajos; Natowicz, René

    2015-01-01

    BACKGROUND Filter feature selection methods compute molecular signatures by selecting subsets of genes in the ranking of a valuation function. The motivations of the valuation functions choice are almost always clearly stated, but those for selecting the genes according to their ranking are hardly ever explicit. METHOD We addressed the computation of molecular signatures by searching the optima of a bi-objective function whose solution space was the set of all possible molecular signatures, ie, the set of subsets of genes. The two objectives were the size of the signature–to be minimized–and the interclass distance induced by the signature–to be maximized–. RESULTS We showed that: 1) the convex combination of the two objectives had exactly n optimal non empty signatures where n was the number of genes, 2) the n optimal signatures were nested, and 3) the optimal signature of size k was the subset of k top ranked genes that contributed the most to the interclass distance. We applied our feature selection method on five public datasets in oncology, and assessed the prediction performances of the optimal signatures as input to the diagonal linear discriminant analysis (DLDA) classifier. They were at the same level or better than the best-reported ones. The predictions were robust, and the signatures were almost always significantly smaller. We studied in more details the performances of our predictive modeling on two breast cancer datasets to predict the response to a preoperative chemotherapy: the performances were higher than the previously reported ones, the signatures were three times smaller (11 versus 30 gene signatures), and the genes member of the signature were known to be involved in the response to chemotherapy. CONCLUSIONS Defining molecular signatures as the optima of a bi-objective function that combined the signature size and the interclass distance was well founded and efficient for prediction in oncogenomics. The complexity of the computation

  10. Translating the IHE Teaching File and Clinical Trial Export (TCE) profile document templates into functional DICOM structured report objects.

    PubMed

    Kamauu, Aaron W C; DuVall, Scott L; Liimatta, Andrew P; Wiggins, Richard H; Avrin, David E

    2008-12-01

    The Integrating the Healthcare Enterprise (IHE) Teaching File and Clinical Trial Export (TCE) integration profile describes a standard workflow for exporting key images from an image manager/archive to a teaching file, clinical trial, or electronic publication application. Two specific digital imaging and communication in medicine (DICOM) structured reports (SR) reference the key images and contain associated case information. This paper presents step-by-step instructions for translating the TCE document templates into functional and complete DICOM SR objects. Others will benefit from these instructions in developing TCE compliant applications. PMID:17805930

  11. Herbig-Haro objects

    NASA Technical Reports Server (NTRS)

    Boehm, K. H.

    1990-01-01

    The IUE (International Ultraviolet Explorer) spectra of Herbig-Haro (HH) objects and their relation to the very detailed optical spectra available for these objects are studied. Useful information about the physics of HH objects in general and especially about their hydrodynamic models which are contained in these IUE observations is outlined. The merged spectra of high excitation, low excitation HH objects (like HH43 and HH47), and peculiar HH objects are discussed. Results of the spatial variation of lines and continua in HH objects are discussed. Their compatibility with predictions for aerodynamic and especially bow shock models is discussed. The problems arising in the interpretation of the continuous energy distribution in the short wavelength range are discussed. They require the presence of other emission mechanisms in addition to the collisionally enhanced two photon continuum. In HH43 the fluorescent H2 line emission comes from a surprisingly small spatial region. Implications of these results are discussed.

  12. Objective and quantitative assessment of motor function in Parkinson's disease-from the perspective of practical applications.

    PubMed

    Yang, Ke; Xiong, Wei-Xi; Liu, Feng-Tao; Sun, Yi-Min; Luo, Susan; Ding, Zheng-Tong; Wu, Jian-Jun; Wang, Jian

    2016-03-01

    Parkinson's disease (PD) is a common neurodegenerative disorder with high morbidity because of the coming aged society. Currently, disease management and the development of new treatment strategies mainly depend on the clinical information derived from rating scales and patients' diaries, which have various limitations with regard to validity, inter-rater variability and continuous monitoring. Recently the prevalence of mobile medical equipment has made it possible to develop an objective, accurate, remote monitoring system for motor function assessment, playing an important role in disease diagnosis, home-monitoring, and severity evaluation. This review discusses the recent development in sensor technology, which may be a promising replacement of the current rating scales in the assessment of motor function of PD. PMID:27047949

  13. Objective and quantitative assessment of motor function in Parkinson’s disease—from the perspective of practical applications

    PubMed Central

    Yang, Ke; Xiong, Wei-Xi; Liu, Feng-Tao; Sun, Yi-Min; Luo, Susan; Ding, Zheng-Tong; Wu, Jian-Jun

    2016-01-01

    Parkinson’s disease (PD) is a common neurodegenerative disorder with high morbidity because of the coming aged society. Currently, disease management and the development of new treatment strategies mainly depend on the clinical information derived from rating scales and patients’ diaries, which have various limitations with regard to validity, inter-rater variability and continuous monitoring. Recently the prevalence of mobile medical equipment has made it possible to develop an objective, accurate, remote monitoring system for motor function assessment, playing an important role in disease diagnosis, home-monitoring, and severity evaluation. This review discusses the recent development in sensor technology, which may be a promising replacement of the current rating scales in the assessment of motor function of PD. PMID:27047949

  14. Ankle proprioceptive acuity is associated with objective as well as self-report measures of balance, mobility, and physical function.

    PubMed

    Deshpande, Nandini; Simonsick, Eleanor; Metter, E Jeffrey; Ko, Seunguk; Ferrucci, Luigi; Studenski, Stephanie

    2016-06-01

    Ankle proprioceptive information is integrated by the central nervous system to generate and modulate muscle contractions for maintaining standing balance. This study evaluated the association of ankle joint proprioception with objective and self-report measures of balance, mobility, and physical function across the adult life span. Seven hundred and ninety participants (age range 24-97 years, 362 women) who completed ankle proprioception assessment between 2010 and 2014 were included in the present study from the population-based cohort of the Baltimore Longitudinal Study of Aging (BLSA), USA. Outcome measures included ankle joint proprioception measured as threshold for perception of passive movement (TPPM); single leg stance time; perceived difficulty for standing balance; usual, fastest, and narrow-path gait speed; walking index; short physical performance battery score; and self-reported activity restriction due to fear of falling. Descriptive variables included age, sex, body mass index, education, strength, and cognition. Analyses of covariance (ANCOVA) in general linear model (GLM) or multinomial logistic regression analyses were performed, as appropriate, to test the hypothesis that balance, mobility, and physical function were significantly different according to TPPM quintiles even after adjusting for relevant covariates. Those with TPPM >2.2° consistently demonstrated poor balance, mobility, and physical function. However, with increase in challenge (single leg stance, fastest walking speed, and SPPB), TPPM >1.4° was associated with significantly worse performance. In conclusion, ankle proprioceptive acuity has an overall graded relationship with objective and self-report measures of balance, mobility, and physical function. However, the cutoff proprioceptive acuity associated with substantial decline or inability to perform could depend on the challenge induced. PMID:27146830

  15. Development of mathematical models and numerical methods for aerodynamic design on multiprocessor computers

    NASA Astrophysics Data System (ADS)

    Maksimov, F. A.; Churakov, D. A.; Shevelev, Yu. D.

    2011-02-01

    Complex-geometry design and grid generation are addressed. The gasdynamic equations are solved, and the numerical results are compared with experimental data. For aerodynamic problems, a suite of mathematical and information technology tools is proposed for the support and management of geometric models of actual objects. Based on the mathematical modeling methods developed, numerical experiments can be performed for a wide class of geometric forms and the aerodynamic properties of aircraft can be predicted with allowance for the viscosity effects.

  16. Experimental aerodynamic and static elastic deformation characterization of low aspect ratio flexible fixed wings applied to micro aerial vehicles

    NASA Astrophysics Data System (ADS)

    Albertani, Roberto

    The concept of micro aerial vehicles (MAVs) is for a small, inexpensive and sometimes expendable platform, flying by remote pilot, in the field or autonomously. Because of the requirement to be flown either by almost inexperienced pilots or by autonomous control, they need to have very reliable and benevolent flying characteristics drive the design guidelines. A class of vehicles designed by the University of Florida adopts a flexible-wing concept, featuring a carbon fiber skeleton and a thin extensible latex membrane skin. Another typical feature of MAVs is a wingspan to propeller diameter ratio of two or less, generating a substantial influence on the vehicle aerodynamics. The main objectives of this research are to elucidate and document the static elastic flow-structure interactions in terms of measurements of the aerodynamic coefficients and wings' deformation as well as to substantiate the proposed inferences regarding the influence of the wings' structural flexibility on their performance; furthermore the research will provide experimental data to support the validation of CFD and FEA numerical models. A unique facility was developed at the University of Florida to implement a combination of a low speed wind tunnel and a visual image correlation system. The models tested in the wind tunnel were fabricated at the University MAV lab and consisted of a series of ten models with an identical geometry but differing in levels of structural flexibility and deformation characteristics. Results in terms of full-field displacements and aerodynamic coefficients from wind tunnel tests for various wind velocities and angles of attack are presented to demonstrate the deformation of the wing under steady aerodynamic load. The steady state effects of the propeller slipstream on the flexible wing's shape and its performance are also investigated. Analytical models of the aerodynamic and propulsion characteristics are proposed based on a multi dimensional linear regression

  17. Modulation of the pupil function of microscope objective lens for multifocal multi-photon microscopy using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Matsumoto, Naoya; Okazaki, Shigetoshi; Takamoto, Hisayoshi; Inoue, Takashi; Terakawa, Susumu

    2014-02-01

    We propose a method for high precision modulation of the pupil function of a microscope objective lens to improve the performance of multifocal multi-photon microscopy (MMM). To modulate the pupil function, we adopt a spatial light modulator (SLM) and place it at the conjugate position of the objective lens. The SLM can generate an arbitrary number of spots to excite the multiple fluorescence spots (MFS) at the desired positions and intensities by applying an appropriate computer-generated hologram (CGH). This flexibility allows us to control the MFS according to the photobleaching level of a fluorescent protein and phototoxicity of a specimen. However, when a large number of excitation spots are generated, the intensity distribution of the MFS is significantly different from the one originally designed due to misalignment of the optical setup and characteristics of the SLM. As a result, the image of a specimen obtained using laser scanning for the MFS has block noise segments because the SLM could not generate a uniform MFS. To improve the intensity distribution of the MFS, we adaptively redesigned the CGH based on the observed MFS. We experimentally demonstrate an improvement in the uniformity of a 10 × 10 MFS grid using a dye solution. The simplicity of the proposed method will allow it to be applied for calibration of MMM before observing living tissue. After the MMM calibration, we performed laser scanning with two-photon excitation to observe a real specimen without detecting block noise segments.

  18. Object Representations in the Temporal Cortex of Monkeys and Humans as Revealed by Functional Magnetic Resonance Imaging

    PubMed Central

    Bell, Andrew H.; Hadj-Bouziane, Fadila; Frihauf, Jennifer B.; Tootell, Roger B. H.; Ungerleider, Leslie G.

    2009-01-01

    Increasing evidence suggests that the neural processes associated with identifying everyday stimuli include the classification of those stimuli into a limited number of semantic categories. How the neural representations of these stimuli are organized in the temporal lobe remains under debate. Here we used functional magnetic resonance imaging (fMRI) to identify correlates for three current hypotheses concerning object representations in the inferior temporal (IT) cortex of monkeys and humans: representations based on animacy, semantic categories, or visual features. Subjects were presented with blocked images of faces, body parts (animate stimuli), objects, and places (inanimate stimuli), and multiple overlapping contrasts were used to identify the voxels most selective for each category. Stimulus representations appeared to segregate according to semantic relationships. Discrete regions selective for animate and inanimate stimuli were found in both species. These regions could be further subdivided into regions selective for individual categories. Notably, face-selective regions were contiguous with body-part-selective regions, and object-selective regions were contiguous with place-selective regions. When category-selective regions in monkeys were tested with blocks of single exemplars, individual voxels showed preferences for visually dissimilar exemplars from the same category and voxels with similar preferences tended to cluster together. Our results provide some novel observations with respect to how stimulus representations are organized in IT cortex. In addition, they further support the idea that representations of complex stimuli in IT cortex are organized into multiple hierarchical tiers, encompassing both semantic and physical properties. PMID:19052111

  19. Long-term cognitive functional limitations post stroke: objective assessment compared with self-evaluations and spouse reports.

    PubMed

    Wendel, Kerstin; Risberg, Jarl; Pessah-Rasmussen, Hélène; Ståhl, Agneta; Iwarsson, Susanne

    2008-09-01

    This study was part of a Swedish interdisciplinary research project targeting accessibility problems in public transport for people with cognitive functional limitations (CFLs). The objective was to describe and compare different assessment perspectives of long-term CFLs among community citizens having had CFLs in the acute stroke phase but with moderate physical limitations. Eighty-four participants in ordinary housing 18-36 months post stroke, initially sampled from a national quality stroke register, received data collection home-visits. The Cognistat screening instrument was used for an objective assessment, and a study-specific questionnaire for self-evaluations of CFLs. A revised form of the latter questionnaire was used for reports from spouses of a subset of 30 participants. The agreement between self-evaluated CFLs and spouse reports was analysed by percentage agreement and Cohen's kappa, whereas differences in ratings were tested by McNemar's test, as were differences between objective and self-evaluated/spouse-reported occurrence of CFLs. Regardless of the different perspectives applied, CFLs were frequent. In absence of significant difference in ratings, the percentage agreement between self-evaluations and spouse reports was good or very good, whereas kappa values were less encouraging. Overall, participants and spouses expressed more CFLs, as compared with the screening. Most consistency was demonstrated for the area of calculation. When researchers and clinicians solely rely on cognitive screenings in their investigations, there is a considerable risk for underestimations of CFLs. PMID:18708846

  20. A computational analysis of the aerodynamic and aeromechanical behavior of the purdue multistage compressor

    NASA Astrophysics Data System (ADS)

    Monk, David James Winchester

    Compressor design programs are becoming more reliant on computational tools to predict and optimize aerodynamic and aeromechanical behavior within a compressor. Recent trends in compressor development continue to push for more efficient, lighter weight, and higher performance machines. To meet these demands, designers must better understand the complex nature of the inherently unsteady flow physics inside of a compressor. As physical testing can be costly and time prohibitive, CFD and other computational tools have become the workhorse during design programs. The objectives of this research were to investigate the aerodynamic and aeromechanical behavior of the Purdue multistage compressor, as well as analyze novel concepts for reducing rotor resonant responses in compressors. Advanced computational tools were utilized to allow an in-depth analysis of the flow physics and structural characteristics of the Purdue compressor, and complement to existing experimental datasets. To analyze the aerodynamic behavior of the compressor a Rolls-Royce CFD code, developed specifically for multistage turbomachinery flows, was utilized. Steady-state computations were performed using the RANS solver on a single-passage mesh. Facility specific boundary conditions were applied to the model, increasing the model fidelity and overall accuracy of the predictions. Detailed investigations into the overall compressor performance, stage performance, and individual blade row performance were completed. Additionally, separation patterns on stator vanes at different loading conditions were investigated by plotting pathlines near the stator suction surfaces. Stator cavity leakage flows were determined to influence the size and extent of stator hub separations. In addition to the aerodynamic analysis, a Rolls-Royce aeroelastic CFD solver was utilized to predict the forced response behavior of Rotor 2, operating at the 1T mode crossing of the Campbell Diagram. This computational tool couples

  1. Fundamental investigation of road vehicle aerodynamics

    NASA Astrophysics Data System (ADS)

    Al-Garni, Abdullah Mohammed

    The present investigation focuses on the aerodynamics of pickup trucks and SUVs. The flow about generic pickup truck and SUV models and a much simpler bluff body model known as the Square Back (SB) model has been documented experimentally. The main objective of the present research is to gain a better understanding of the pickup truck and SUV aerodynamics through mean and unsteady pressure measurements as well as detailed flow field measurements using PIV. The mean pressure results of the pickup truck show that the pressure outside the tailgate is higher than inside the tailgate suggesting that the tailgate reduces aerodynamic drag. Pressure fluctuation spectra indicate a spectral peak at a Strouhal number of ˜0.094 for the SB model and ˜0.07 for the SUV and pickup truck models. Velocity field measurements in horizontal planes behind the SUV and SB models show a similar flow pattern characterized by a recirculation region at the base of the model with length about 1.15 times the width of the model. The flow in the symmetry plane varies considerably between models. For the SUV there is strong upwash while for the pickup truck, there is a recirculation region inside the bed and a strong downwash behind the tailgate. For the present pickup truck model the bed recirculation region is bounded by a shear layer which does not interact directly with the tailgate. Proper Orthogonal Decomposition (POD) analysis was applied to the PIV data at selected planes in order to identify the most energetic structures in the wake of these models. It is shown that the first two modes contain almost 20% of the total fluctuation energy while 70% of energy is captured by the first twenty modes. When the most energetic modes were used in reconstruction of the flow field in the wake of SB and SUV, flapping and breathing like motions resulted. For the pickup truck it is shown that some modes capture the energy in the underbody shear layer while other modes seem to contribute more to the cab

  2. Investigation of the transient aerodynamic phenomena associated with passing manoeuvres

    NASA Astrophysics Data System (ADS)

    Noger, C.; Regardin, C.; Széchényi, E.

    2005-11-01

    Passing manoeuvres and crosswind can have significant effects on the stability of road vehicles. The transient aerodynamics, which interacts with suspension, steering geometry and driver reaction is not well understood. When two vehicles overtake or cross, they mutually influence the flow field around each other, and under certain conditions, can generate severe gust loads that act as additional forces on both vehicles. The transient forces acting on them are a function of the longitudinal and transverse spacings and of the relative velocity between the two vehicles. Wind tunnel experiments have been conducted in one of the automotive wind tunnels of the Institut Aérotechnique of Saint-Cyr l’École to simulate the transient overtaking process between two models of a simple generic automobile shape. The tests were designed to study the effects of various parameters such as the longitudinal and transverse spacing, the relative velocity and the crosswind on the aerodynamic forces and moments generated on the overtaken and overtaking vehicles. Test results characterize the transient aerodynamic side force as well as the yawing moment coefficients in terms of these parameters. Measurements of the drag force coefficient as well as the static pressure distribution around the overtaken vehicle complete the understanding. The main results indicate the aerodynamic coefficients of the overtaken vehicle to be velocity independent within the limit of the test parameters, while unsteady aerodynamic effects appear in the case of an overtaking vehicle. The mutual interference effects between the vehicles vary as a linear function of the transverse spacing and the crosswind does not really generate any new unsteady behaviour.

  3. The role of unsteady aerodynamics in aeroacoustics

    NASA Technical Reports Server (NTRS)

    Pao, S. Paul

    1988-01-01

    The role of acoustics and unsteady aerodynamics research in understanding the fundamental physics of time-dependent fluid phenomena is reviewed. The key issues are illustrated by considering the sound radiation of turbulent jets and the aeroacoustics of rotating bodies such as helicopter rotors. The importance of computational methods as a link between aerodynamics and acoustics is also discussed. It is noted that where acoustic analogy techniques are sufficiently accurate, unsteady aerodynamics can be used for acoustic prediction. In supersonic problems where acoustics and aerodynamics are coupled, an integrated nonlinear analysis can provide an accurate problem solution.

  4. HIAD-2 (Hypersonic Inflatable Aerodynamic Decelerator)

    NASA Video Gallery

    The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) project is a disruptive technology that will accommodate the atmospheric entry of heavy payloads to planetary bodies such as Mars. HIAD over...

  5. Computational aerodynamics applications to transport aircraft design

    NASA Technical Reports Server (NTRS)

    Henne, P. A.

    1983-01-01

    Examples are cited in assessing the effect that computational aerodynamics has had on the design of transport aircraft. The application of computational potential flow methods to wing design and to high-lift system design is discussed. The benefits offered by computational aerodynamics in reducing design cost, time, and risk are shown to be substantial.These aerodynamic methods have proved to be particularly effective in exposing inferior or poor aerodynamic designs. Particular attention is given to wing design, where the results have been dramatic.

  6. A new slant on the inverse problems of electromagnetic frequency sounding: 'convexification' of a multiextremal objective function via the Carleman weight functions

    NASA Astrophysics Data System (ADS)

    Klibanov, Michael V.; Timonov, Alexandre

    2001-12-01

    Some coefficient inverse problems of electromagnetic frequency sounding of inhomogeneous media are considered. Such problems occur in many areas of applied physics, such as the geophysical exploration of gas, oil and mineral deposits, reservoir monitoring, marine acoustics and electromagnetics, optical sensing, and radio physics. Reformulating these problems in terms of nonlinear least squares, also known in the applied literature as matched field processing, often leads to a multiextremal and multidimensional objective function. This makes it extremely difficult to find its global extremum which corresponds to the solution of the original problem. It is shown in this paper that an inverse problem of frequency sounding can first be identically transformed to a certain boundary value problem which does not explicitly contain an unknown coefficient. The nonlinear least squares are then applied to the transformed problem. Using the weight functions associated with the Carleman estimates for the Laplace operator, an objective function is constructed in such a way that it is strictly convex on a certain compact set. The feasibility of the proposed approach is demonstrated in computational experiments with a model problem of magnetotelluric frequency sounding of layered media.

  7. Orion Aerodynamics for Hypersonic Free Molecular to Continuum Conditions

    NASA Technical Reports Server (NTRS)

    Moss, James N.; Greene, Francis A.; Boyles, Katie A.

    2006-01-01

    Numerical simulations are performed for the Orion Crew Module, previously known as the Crew Exploration Vehicle (CEV) Command Module, to characterize its aerodynamics during the high altitude portion of its reentry into the Earth's atmosphere, that is, from free molecular to continuum hypersonic conditions. The focus is on flow conditions similar to those that the Orion Crew Module would experience during a return from the International Space Station. The bulk of the calculations are performed with two direct simulation Monte Carlo (DSMC) codes, and these data are anchored with results from both free molecular and Navier-Stokes calculations. Results for aerodynamic forces and moments are presented that demonstrate their sensitivity to rarefaction, that is, for free molecular to continuum conditions (Knudsen numbers of 111 to 0.0003). Also included are aerodynamic data as a function of angle of attack for different levels of rarefaction and results that demonstrate the aerodynamic sensitivity of the Orion CM to a range of reentry velocities (7.6 to 15 km/s).

  8. Aerodynamic Models for the Low Density Supersonic Declerator (LDSD) Supersonic Flight Dynamics Test (SFDT)

    NASA Technical Reports Server (NTRS)

    Van Norman, John W.; Dyakonov, Artem; Schoenenberger, Mark; Davis, Jody; Muppidi, Suman; Tang, Chun; Bose, Deepak; Mobley, Brandon; Clark, Ian

    2015-01-01

    An overview of pre-flight aerodynamic models for the Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) campaign is presented, with comparisons to reconstructed flight data and discussion of model updates. The SFDT campaign objective is to test Supersonic Inflatable Aerodynamic Decelerator (SIAD) and large supersonic parachute technologies at high altitude Earth conditions relevant to entry, descent, and landing (EDL) at Mars. Nominal SIAD test conditions are attained by lifting a test vehicle (TV) to 36 km altitude with a large helium balloon, then accelerating the TV to Mach 4 and and 53 km altitude with a solid rocket motor. The first flight test (SFDT-1) delivered a 6 meter diameter robotic mission class decelerator (SIAD-R) to several seconds of flight on June 28, 2014, and was successful in demonstrating the SFDT flight system concept and SIAD-R. The trajectory was off-nominal, however, lofting to over 8 km higher than predicted in flight simulations. Comparisons between reconstructed flight data and aerodynamic models show that SIAD-R aerodynamic performance was in good agreement with pre-flight predictions. Similar comparisons of powered ascent phase aerodynamics show that the pre-flight model overpredicted TV pitch stability, leading to underprediction of trajectory peak altitude. Comparisons between pre-flight aerodynamic models and reconstructed flight data are shown, and changes to aerodynamic models using improved fidelity and knowledge gained from SFDT-1 are discussed.

  9. 3-D Navier-Stokes Analysis of Blade Root Aerodynamics for a Tiltrotor Aircraft In Cruise

    NASA Technical Reports Server (NTRS)

    Romander, Ethan

    2006-01-01

    The blade root area of a tiltrotor aircraft's rotor is constrained by a great many factors, not the least of which is aerodynamic performance in cruise. For this study, Navier-Stokes CFD techniques are used to study the aerodynamic performance in cruise of a rotor design as a function of airfoil thickness along the blade and spinner shape. Reducing airfoil thickness along the entire blade will be shown to have the greatest effect followed by smaller but still significant improvements achieved by reducing the thickness of root airfoils only. Furthermore, altering the shape of the spinner will be illustrated as a tool to tune the aerodynamic performance very near the blade root.

  10. Constrained Multipoint Aerodynamic Shape Optimization Using an Adjoint Formulation and Parallel Computers

    NASA Technical Reports Server (NTRS)

    Reuther, James; Jameson, Antony; Alonso, Juan Jose; Rimlinger, Mark J.; Saunders, David

    1997-01-01

    An aerodynamic shape optimization method that treats the design of complex aircraft configurations subject to high fidelity computational fluid dynamics (CFD), geometric constraints and multiple design points is described. The design process will be greatly accelerated through the use of both control theory and distributed memory computer architectures. Control theory is employed to derive the adjoint differential equations whose solution allows for the evaluation of design gradient information at a fraction of the computational cost required by previous design methods. The resulting problem is implemented on parallel distributed memory architectures using a domain decomposition approach, an optimized communication schedule, and the MPI (Message Passing Interface) standard for portability and efficiency. The final result achieves very rapid aerodynamic design based on a higher order CFD method. In order to facilitate the integration of these high fidelity CFD approaches into future multi-disciplinary optimization (NW) applications, new methods must be developed which are capable of simultaneously addressing complex geometries, multiple objective functions, and geometric design constraints. In our earlier studies, we coupled the adjoint based design formulations with unconstrained optimization algorithms and showed that the approach was effective for the aerodynamic design of airfoils, wings, wing-bodies, and complex aircraft configurations. In many of the results presented in these earlier works, geometric constraints were satisfied either by a projection into feasible space or by posing the design space parameterization such that it automatically satisfied constraints. Furthermore, with the exception of reference 9 where the second author initially explored the use of multipoint design in conjunction with adjoint formulations, our earlier works have focused on single point design efforts. Here we demonstrate that the same methodology may be extended to treat

  11. Inner workings of aerodynamic sweep

    SciTech Connect

    Wadia, A.R.; Szucs, P.N.; Crall, D.W.

    1998-10-01

    The recent trend in using aerodynamic sweep to improve the performance of transonic blading has been one of the more significant technological evolutions for compression components in turbomachinery. This paper reports on the experimental and analytical assessment of the pay-off derived from both aft and forward sweep technology with respect to aerodynamic performance and stability. The single-stage experimental investigation includes two aft-swept rotors with varying degree and type of aerodynamic sweep and one swept forward rotor. On a back-to-back test basis, the results are compared with an unswept rotor with excellent performance and adequate stall margin. Although designed to satisfy identical design speed requirements as the unswept rotor, the experimental results reveal significant variations in efficiency and stall margin with the swept rotors. At design speed, all the swept rotors demonstrated a peak stage efficiency level that was equal to that of the unswept rotor. However, the forward-swept rotor achieved the highest rotor-alone peak efficiency. At the same time, the forward-swept rotor demonstrated a significant improvement in stall margin relative to the already satisfactory level achieved by the unswept rotor. Increasing the level of aft sweep adversely affected the stall margin. A three-dimensional viscous flow analysis was used to assist in the interpretation of the data. The reduced shock/boundary layer interaction, resulting from reduced axial flow diffusion and less accumulation of centrifuged blade surface boundary layer at the tip, was identified as the prime contributor to the enhanced performance with forward sweep. The impact of tip clearance on the performance and stability for one of the aft-swept rotors was also assessed.

  12. Radiobiology for eye plaque brachytherapy and evaluation of implant duration and radionuclide choice using an objective function

    SciTech Connect

    Gagne, Nolan L.; Leonard, Kara L.; Rivard, Mark J.

    2012-06-15

    Purpose: Clinical optimization of Collaborative Ocular Melanoma Study (COMS) eye plaque brachytherapy is currently limited to tumor coverage, consensus prescription dosage, and dose calculations to ocular structures. The biologically effective dose (BED) of temporary brachytherapy treatments is a function of both chosen radionuclide R and implant duration T. This study endeavored to evaluate BED delivered to the tumor volume and surrounding ocular structures as a function of plaque position P, prescription dose, R, and T. Methods: Plaque-heterogeneity-corrected dose distributions were generated with MCNP5 for the range of currently available COMS plaques loaded with sources using three available low-energy radionuclides. These physical dose distributions were imported into the PINNACLE{sup 3} treatment planning system using the TG-43 hybrid technique and used to generate dose volume histograms for a T = 7 day implant within a reference eye geometry including the ciliary body, cornea, eyelid, foveola, lacrimal gland, lens, optic disc, optic nerve, retina, and tumor at eight standard treatment positions. The equation of Dale and Jones was employed to create biologically effective dose volume histograms (BEDVHs), allowing for BED volumetric analysis of all ROIs. Isobiologically effective prescription doses were calculated for T = 5 days down to 0.01 days, with BEDVHs subsequently generated for all ROIs using correspondingly reduced prescription doses. Objective functions were created to evaluate the BEDVHs as a function of R and T. These objective functions are mathematically accessible and sufficiently general to be applied to temporary or permanent brachytherapy implants for a variety of disease sites. Results: Reducing T from 7 to 0.01 days for a 10 mm plaque produced an average BED benefit of 26%, 20%, and 17% for {sup 103}Pd, {sup 125}I, and {sup 131}Cs, respectively, for all P; 16 and 22 mm plaque results were more position-dependent. {sup 103}Pd produced a 16

  13. Progress in computational unsteady aerodynamics

    NASA Technical Reports Server (NTRS)

    Obayashi, Shigeru

    1993-01-01

    After vigorous development for over twenty years, Computational Fluid Dynamics (CFD) in the field of aerospace engineering has arrived at a turning point toward maturity. This paper discusses issues related to algorithm development for the Euler/Navier Stokes equations, code validation and recent applications of CFD for unsteady aerodynamics. Algorithm development is a fundamental element for a good CFD program. Code validation tries to bridge the reliability gap between CFD and experiment. Many of the recent applications also take a multidisciplinary approach, which is a future trend for CFD applications. As computers become more affordable, CFD is expected to be a better scientific and engineering tool.

  14. Simulation of iced wing aerodynamics

    NASA Technical Reports Server (NTRS)

    Potapczuk, M. G.; Bragg, M. B.; Kwon, O. J.; Sankar, L. N.

    1991-01-01

    The sectional and total aerodynamic load characteristics of moderate aspect ratio wings with and without simulated glaze leading edge ice were studied both computationally, using a three dimensional, compressible Navier-Stokes solver, and experimentally. The wing has an untwisted, untapered planform shape with NACA 0012 airfoil section. The wing has an unswept and swept configuration with aspect ratios of 4.06 and 5.0. Comparisons of computed surface pressures and sectional loads with experimental data for identical configurations are given. The abrupt decrease in stall angle of attack for the wing, as a result of the leading edge ice formation, was demonstrated numerically and experimentally.

  15. The basic aerodynamics of floatation

    SciTech Connect

    Davies, M.J.; Wood, D.H.

    1983-09-01

    The original derivation of the basic theory governing the aerodynamics of both hovercraft and modern floatation ovens, requires the validity of some extremely crude assumptions. However, the basic theory is surprisingly accurate. It is shown that this accuracy occurs because the final expression of the basic theory can be derived by approximating the full Navier-Stokes equations in a manner that clearly shows the limitations of the theory. These limitations are used in discussing the relatively small discrepancies between the theory and experiment, which may not be significant for practical purposes.

  16. Aerodynamics. [Numerical simulation using supercomputers

    SciTech Connect

    Graves, R.A. Jr.

    1988-01-01

    A projection is made of likely improvements in the economics of commercial aircraft operation due to developments in aerodynamics in the next half-century. Notable among these improvements are active laminar flow control techniques' application to third-generation SSTs, in order to achieve an L/D value of about 20; this is comparable to current subsonic transports, and has the further consequence of reducing cabin noise. Wave-cancellation systems may also be used to eliminate sonic boom overpressures, and rapid-combustion systems may be able to eliminate all pollutants from jet exhausts other than CO/sub 2/.

  17. Aerodynamic applications of infrared thermography

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Alderfer, David W.

    1989-01-01

    A series of wind tunnel experiments were conducted as part of a systematic study for evaluation of infrared thermography as a viable non-intrusive thermal measurement technique for aerodynamic applications. The experiments consisted of obtaining steady-state surface temperature and convective heat transfer rates for a uniformly heated cylinder in transverse flow with a Reynolds number range of 46,000 to 250,000. The calculated convective heat transfer rates were in general agreement with classical data. Furthermore, IR thermography provided valuable real-time fluid dynamic information such as visualization of flow separation, transition and vortices.

  18. Sensitivity analysis, calibration, and testing of a distributed hydrological model using error-based weighting and one objective function

    USGS Publications Warehouse

    Foglia, L.; Hill, M.C.; Mehl, S.W.; Burlando, P.

    2009-01-01

    We evaluate the utility of three interrelated means of using data to calibrate the fully distributed rainfall-runoff model TOPKAPI as applied to the Maggia Valley drainage area in Switzerland. The use of error-based weighting of observation and prior information data, local sensitivity analysis, and single-objective function nonlinear regression provides quantitative evaluation of sensitivity of the 35 model parameters to the data, identification of data types most important to the calibration, and identification of correlations among parameters that contribute to nonuniqueness. Sensitivity analysis required only 71 model runs, and regression required about 50 model runs. The approach presented appears to be ideal for evaluation of models with long run times or as a preliminary step to more computationally demanding methods. The statistics used include composite scaled sensitivities, parameter correlation coefficients, leverage, Cook's D, and DFBETAS. Tests suggest predictive ability of the calibrated model typical of hydrologic models. Copyright 2009 by the American Geophysical Union.

  19. Sensitivity analysis, calibration, and testing of a distributed hydrological model using error-based weighting and one objective function

    NASA Astrophysics Data System (ADS)

    Foglia, L.; Hill, M. C.; Mehl, S. W.; Burlando, P.

    2009-06-01

    We evaluate the utility of three interrelated means of using data to calibrate the fully distributed rainfall-runoff model TOPKAPI as applied to the Maggia Valley drainage area in Switzerland. The use of error-based weighting of observation and prior information data, local sensitivity analysis, and single-objective function nonlinear regression provides quantitative evaluation of sensitivity of the 35 model parameters to the data, identification of data types most important to the calibration, and identification of correlations among parameters that contribute to nonuniqueness. Sensitivity analysis required only 71 model runs, and regression required about 50 model runs. The approach presented appears to be ideal for evaluation of models with long run times or as a preliminary step to more computationally demanding methods. The statistics used include composite scaled sensitivities, parameter correlation coefficients, leverage, Cook's D, and DFBETAS. Tests suggest predictive ability of the calibrated model typical of hydrologic models.

  20. General Theory of Aerodynamic Instability and the Mechanism of Flutter

    NASA Technical Reports Server (NTRS)

    Theodorsen, Theodore

    1979-01-01

    The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom were determined. The problem resolves itself into the solution of certain definite integrals, which were identified as Bessel functions of the first and second kind, and of zero and first order. The theory, based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing section theory relating to the steady case. The air forces being known, the mechanism of aerodynamic instability was analyzed. An exact solution, involving potential flow and the adoption of the Kutta condition, was derived. The solution is of a simple form and is expressed by means of an auxiliary parameter k. The flutter velocity, treated as the unknown quantity, was determined as a function of a certain ratio of the frequencies in the separate degrees of freedom for any magnitudes and combinations of the airfoil-aileron parameters.

  1. Neural correlates of conceptual object priming in young and older adults: an event-related functional magnetic resonance imaging study.

    PubMed

    Ballesteros, Soledad; Bischof, Gérard N; Goh, Joshua O; Park, Denise C

    2013-04-01

    In this event-related functional magnetic resonance imaging study, we investigated age-related differences in brain activity associated with conceptual repetition priming in young and older adults. Participants performed a speeded "living/nonliving" classification task with 3 repetitions of familiar objects. Both young and older adults showed a similar magnitude of behavioral priming to repeated objects and evidenced repetition-related activation reductions in fusiform gyrus, superior occipital, middle, and inferior temporal cortex, and inferior frontal and insula regions. The neural priming effect in young adults was extensive and continued through both the second and third stimulus repetitions, and neural priming in older adults was markedly attenuated and reached floor at the second repetition. In young adults, greater neural priming in multiple brain regions correlated with greater behavioral facilitation and in older adults, only activation reduction in the left inferior frontal correlated with faster behavioral responses. These findings provide evidence for altered neural priming in older adults despite preserved behavioral priming, and suggest the possibility that age-invariant behavioral priming is observed as a result of more sustained neural processing of stimuli in older adults which might be a form of compensatory neural activity. PMID:23102512

  2. Orion Crew Module Aerodynamic Testing

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Bibb, Karen L.; Brauckmann, Gregory J.; Rhode, Matthew N.; Owens, Bruce; Chan, David T.; Walker, Eric L.; Bell, James H.; Wilson, Thomas M.

    2011-01-01

    The Apollo-derived Orion Crew Exploration Vehicle (CEV), part of NASA s now-cancelled Constellation Program, has become the reference design for the new Multi-Purpose Crew Vehicle (MPCV). The MPCV will serve as the exploration vehicle for all near-term human space missions. A strategic wind-tunnel test program has been executed at numerous facilities throughout the country to support several phases of aerodynamic database development for the Orion spacecraft. This paper presents a summary of the experimental static aerodynamic data collected to-date for the Orion Crew Module (CM) capsule. The test program described herein involved personnel and resources from NASA Langley Research Center, NASA Ames Research Center, NASA Johnson Space Flight Center, Arnold Engineering and Development Center, Lockheed Martin Space Sciences, and Orbital Sciences. Data has been compiled from eight different wind tunnel tests in the CEV Aerosciences Program. Comparisons are made as appropriate to highlight effects of angle of attack, Mach number, Reynolds number, and model support system effects.

  3. X-33 Hypersonic Aerodynamic Characteristics

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Nowak, Robert J.; Thompson, Richard A.; Hollis, Brian R.; Prabhu, Ramadas K.

    1999-01-01

    Lockheed Martin Skunk Works, under a cooperative agreement with NASA, will design, build, and fly the X-33, a half-scale prototype of a rocket-based, single-stage-to-orbit (SSTO), reusable launch vehicle (RLV). A 0.007-scale model of the X-33 604BOO02G configuration was tested in four hypersonic facilities at the NASA Langley Research Center to examine vehicle stability and control characteristics and to populate the aerodynamic flight database for the hypersonic regime. The vehicle was found to be longitudinally controllable with less than half of the total body flap deflection capability across the angle of attack range at both Mach 6 and Mach 10. Al these Mach numbers, the vehicle also was shown to be longitudinally stable or neutrally stable for typical (greater than 20 degrees) hypersonic flight attitudes. This configuration was directionally unstable and the use of reaction control jets (RCS) will be necessary to control the vehicle at high angles of attack in the hypersonic flight regime. Mach number and real gas effects on longitudinal aerodynamics were shown to be small relative to X-33 control authority.

  4. X-33 Hypersonic Aerodynamic Characteristics

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Nowak, Robert J.; Thompson, Richard A.; Hollis, Brian R.; Prabhu, Ramadas K.

    1999-01-01

    Lockheed Martin Skunk Works, under a cooperative agreement with NASA, will build and fly the X-33, a half-scale prototype of a rocket-based, single-stage-to-orbit (SSTO), reusable launch vehicle (RLV). A 0.007-scale model of the X-33 604B0002G configuration was tested in four hypersonic facilities at the NASA Langley Research Center to examine vehicle stability and control characteristics and to populate an aerodynamic flight database in the hypersonic regime. The vehicle was found to be longitudinally controllable with less than half of the total body flap deflection capability across the angle of attack range at both Mach 6 and Mach 10. At these Mach numbers, the vehicle also was shown to be longitudinally stable or neutrally stable for typical (greater than 20 degrees) hypersonic flight attitudes. This configuration was directionally unstable and the use of reaction control jets (RCS) will be necessary to control the vehicle at high angles of attack in the hypersonic flight regime. Mach number and real gas effects on longitudinal aerodynamics were shown to be small relative to X-33 control authority.

  5. X-33 Hypersonic Aerodynamic Characteristics

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Nowak, Robert J.; Thompson, Richard A.; Hollis, Brian R.; Prabhu, Ramadas K.

    1999-01-01

    Lockheed Martin Skunk Works, under a cooperative agreement with NASA, will build and fly the X-33, a half-scale prototype of a rocket-based, single-stage-to-orbit (SSTO), reusable launch vehicle (RLV). A 0.007-scale model of the X-33 604B0002G configuration was tested in four hypersonic facilities at the NASA Langley Research Center to examine vehicle stability and control characteristics and to populate an aerodynamic flight database i n the hypersonic regime. The vehicle was found to be longitudinally controllable with less than half of the total body flap deflection capability across the angle of attack range at both Mach 6 and Mach 10. At these Mach numbers, the vehicle also was shown to be longitudinally stable or neutrally stable for typical (greater than 20 degrees) hypersonic flight attitudes. This configuration was directionally unstable and the use of reaction control jets (RCS) will be necessary to control the vehicle at high angles of attack in the hypersonic flight regime. Mach number and real gas effects on longitudinal aerodynamics were shown to be small relative to X-33 control authority.

  6. X-33 Hypersonic Aerodynamic Characteristics

    NASA Technical Reports Server (NTRS)

    Murphy, Kelly J.; Nowak, Robert J.; Thompson, Richard A.; Hollis, Brian R.; Prabhu, Ramadas K.

    1999-01-01

    Lockheed Martin Skunk Works, under a cooperative agreement with NASA, will build and fly the X-33, a half-scale prototype of a rocket-based, single-stage-to-orbit (SSTO), reusable launch vehicle (RLV). A 0.007-scale model of the X-33 604B0002G configuration was tested in four hypersonic facilities at the NASA Langley Research Center to examine vehicle stability and control characteristics and to populate an aerodynamic flight database in the hypersonic regime, The vehicle was found to be longitudinally controllable with less than half of the total body flap deflection capability across the angle of attack range at both Mach 6 and Mach 10. At these Mach numbers, the vehicle also was shown to be longitudinally stable or neutrally stable for typical (greater than 20 degrees) hypersonic flight attitudes. This configuration was directionally unstable and the use of reaction control jets (RCS) will be necessary to control the vehicle at high angles of attack in the hypersonic flight regime. Mach number and real gas effects on longitudinal aerodynamics were shown to be small relative to X-33 control authority.

  7. Causal functional contributions and interactions in the attention network of the brain: an objective multi-perturbation analysis.

    PubMed

    Zavaglia, Melissa; Hilgetag, Claus C

    2016-06-01

    Spatial attention is a prime example for the distributed network functions of the brain. Lesion studies in animal models have been used to investigate intact attentional mechanisms as well as perspectives for rehabilitation in the injured brain. Here, we systematically analyzed behavioral data from cooling deactivation and permanent lesion experiments in the cat, where unilateral deactivation of the posterior parietal cortex (in the vicinity of the posterior middle suprasylvian cortex, pMS) or the superior colliculus (SC) cause a severe neglect in the contralateral hemifield. Counterintuitively, additional deactivation of structures in the opposite hemisphere reverses the deficit. Using such lesion data, we employed a game-theoretical approach, multi-perturbation Shapley value analysis (MSA), for inferring functional contributions and network interactions of bilateral pMS and SC from behavioral performance in visual attention studies. The approach provides an objective theoretical strategy for lesion inferences and allows a unique quantitative characterization of regional functional contributions and interactions on the basis of multi-perturbations. The quantitative analysis demonstrated that right posterior parietal cortex and superior colliculus made the strongest positive contributions to left-field orienting, while left brain regions had negative contributions, implying that their perturbation may reverse the effects of contralateral lesions or improve normal function. An analysis of functional modulations and interactions among the regions revealed redundant interactions (implying functional overlap) between regions within each hemisphere, and synergistic interactions between bilateral regions. To assess the reliability of the MSA method in the face of variable and incomplete input data, we performed a sensitivity analysis, investigating how much the contribution values of the four regions depended on the performance of specific configurations and on the

  8. Aerodynamic pressure and flow-visualization measurement from a rotating wind turbine blade

    SciTech Connect

    Butterfield, C P

    1988-11-01

    Aerodynamic, load, flow-visualization, and inflow measurements have been made on a 10-m, three-bladed, downwind, horizontal-axis wind turbine (HAWT). A video camera mounted on the rotor was used to record nighttime and daytime video images of tufts attached to the low-pressure side of a constant-chord, zero-twist blade. Load measurements were made using strain gages mounted at every 10% of the blade's span. Pressure measurements were made at 80% of the blade's span. Pressure taps were located at 32 chordwise positions, revealing pressure distributions comparable with wind tunnel data. Inflow was measured using a vertical-plane array of eight propvane and five triaxial (U-V-W) prop-type anemometers located 10 m upwind in the predominant wind direction. One objective of this comprehensive research program was to study the effects of blade rotation on aerodynamic behavior below, near, and beyond stall. To this end, flow patterns are presented here that reveal the dynamic and steady behavior of flow conditions on the blade. Pressure distributions are compared to flow patterns and two-dimensional wind tunnel data. Separation boundary locations are shown that change as a function of spanwise location, pitch angle, and wind speed. 6 refs., 23 figs., 1 tab.

  9. Distributed Aerodynamic Sensing and Processing Toolbox

    NASA Technical Reports Server (NTRS)

    Brenner, Martin; Jutte, Christine; Mangalam, Arun

    2011-01-01

    A Distributed Aerodynamic Sensing and Processing (DASP) toolbox was designed and fabricated for flight test applications with an Aerostructures Test Wing (ATW) mounted under the fuselage of an F-15B on the Flight Test Fixture (FTF). DASP monitors and processes the aerodynamics with the structural dynamics using nonintrusive, surface-mounted, hot-film sensing. This aerodynamic measurement tool benefits programs devoted to static/dynamic load alleviation, body freedom flutter suppression, buffet control, improvement of aerodynamic efficiency through cruise control, supersonic wave drag reduction through shock control, etc. This DASP toolbox measures local and global unsteady aerodynamic load distribution with distributed sensing. It determines correlation between aerodynamic observables (aero forces) and structural dynamics, and allows control authority increase through aeroelastic shaping and active flow control. It offers improvements in flutter suppression and, in particular, body freedom flutter suppression, as well as aerodynamic performance of wings for increased range/endurance of manned/ unmanned flight vehicles. Other improvements include inlet performance with closed-loop active flow control, and development and validation of advanced analytical and computational tools for unsteady aerodynamics.

  10. The aerodynamics of small Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Schmitz, F. W.

    1980-01-01

    Aerodynamic characteristics of wing model gliders and bird wings in particular are discussed. Wind tunnel measurements and aerodynamics of small Reynolds numbers are enumerated. Airfoil behavior in the critical transition from laminar to turbulent boundary layer, which is more important to bird wing models than to large airplanes, was observed. Experimental results are provided, and an artificial bird wing is described.

  11. Future Computer Requirements for Computational Aerodynamics

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Recent advances in computational aerodynamics are discussed as well as motivations for and potential benefits of a National Aerodynamic Simulation Facility having the capability to solve fluid dynamic equations at speeds two to three orders of magnitude faster than presently possible with general computers. Two contracted efforts to define processor architectures for such a facility are summarized.

  12. Aerodynamic seal assemblies for turbo-machinery

    SciTech Connect

    Bidkar, Rahul Anil; Wolfe, Christopher; Fang, Biao

    2015-09-29

    The present application provides an aerodynamic seal assembly for use with a turbo-machine. The aerodynamic seal assembly may include a number of springs, a shoe connected to the springs, and a secondary seal positioned about the springs and the shoe.

  13. Review of aerodynamic design in the Netherlands

    NASA Technical Reports Server (NTRS)

    Labrujere, Th. E.

    1991-01-01

    Aerodynamic design activities in the Netherlands, which take place mainly at Fokker, the National Aerospace Laboratory (NLR), and Delft University of Technology (TUD), are discussed. The survey concentrates on the development of the Fokker 100 wing, glider design at TUD, and research at NLR in the field of aerodynamic design. Results are shown to illustrate these activities.

  14. First NASA/Industry High-Speed Research Configuration Aerodynamics Workshop. Part 1

    NASA Technical Reports Server (NTRS)

    Wood, Richard M. (Editor)

    1999-01-01

    This publication is a compilation of documents presented at the First NASA/Industry High Speed Research Configuration Aerodynamics Workshop held on February 27-29, 1996 at NASA Langley Research Center. The purpose of the workshop was to bring together the broad spectrum of aerodynamicists, engineers, and scientists working within the Configuration Aerodynamics element of the HSR Program to collectively evaluate the technology status and to define the needs within Computational Fluid Dynamics (CFD) Analysis Methodology, Aerodynamic Shape Design, Propulsion/Airframe Integration (PAI), Aerodynamic Performance, and Stability and Control (S&C) to support the development of an economically viable High Speed Civil Transport (HSCT) aircraft. To meet these objectives, papers were presented by representative from NASA Langley, Ames, and Lewis Research Centers; Boeing, McDonnell Douglas, Northrop-Grumman, Lockheed-Martin, Vigyan, Analytical Services, Dynacs, and RIACS.

  15. First NASA/Industry High-Speed Research Configuration Aerodynamics Workshop

    NASA Technical Reports Server (NTRS)

    Wood, Richard M. (Editor)

    1999-01-01

    This publication is a compilation of documents presented at the First NASA/Industry High Speed Research Configuration Aerodynamics Workshop held on February 27-29, 1996 at NASA Langley Research Center. The purpose of the workshop was to bring together the broad spectrum of aerodynamicists, engineers, and scientists working within the Configuration Aerodynamics element of the HSR Program to collectively evaluate the technology status and to define the needs within Computational Fluid Dynamics (CFD) Analysis Methodology, Aerodynamic Shape Design, Propulsion/Airframe Integration (PAI), Aerodynamic Performance, and Stability and Control (S&C) to support the development of an economically viable High Speed Civil Transport (HSCT) aircraft. To meet these objectives, papers were presented by representative from NASA Langley, Ames, and Lewis Research Centers; Boeing, McDonnell Douglas, Northrop-Grumman, Lockheed-Martin, Vigyan, Analytical Services, Dynacs, and RIACS.

  16. First NASA/Industry High-Speed Research Configuration Aerodynamics Workshop. Pt. 2

    NASA Technical Reports Server (NTRS)

    Wood, Richard M. (Editor)

    1999-01-01

    This publication is a compilation of documents presented at the First NASA Industry High Speed Research Configuration Aerodynamics Workshop held on February 27-29, 1996 at NASA Langley Research Center. The purpose of the workshop was to bring together the broad spectrum of aerodynamicists, engineers, and scientists working within the Configuration Aerodynamics element of the HSR Program to collectively evaluate the technology status and to define the needs within Computational Fluid Dynamics (CFD) Analysis Methodology, Aerodynamic Shape Design, Propulsion/Airframe Integration (PAI), Aerodynamic Performance, and Stability and Control (S&C) to support the development of an economically viable High Speed Civil Transport (HSCT) aircraft. To meet these objectives, papers were presented by representatives from NASA Langley, Ames, and Lewis Research Centers; Boeing, McDonnell Douglas, Northrop-Grumman, Lockheed-Martin, Vigyan, Analytical Services, Dynacs, and RIACS.

  17. Individual Monitoring of Vocal Effort With Relative Fundamental Frequency: Relationships With Aerodynamics and Listener Perception

    PubMed Central

    Michener, Carolyn M.; Eadie, Tanya L.; Stepp, Cara E.

    2015-01-01

    Purpose The acoustic measure relative fundamental frequency (RFF) was investigated as a potential objective measure to track variations in vocal effort within and across individuals. Method Twelve speakers with healthy voices created purposeful modulations in their vocal effort during speech tasks. RFF and an aerodynamic measure of vocal effort, the ratio of sound pressure level to subglottal pressure level, were estimated from the aerodynamic and acoustic signals. Twelve listeners also judged the speech samples for vocal effort using the visual sort and rate method. Results Relationships between RFF and both the aerodynamic and perceptual measures of vocal effort were weak across speakers (R2 = .06–.26). Within speakers, relationships were variable but much stronger on average (R2 = .45–.56). Conclusions RFF showed stronger relationships between both the aerodynamic and perceptual measures of vocal effort when examined within individuals versus across individuals. Future work is necessary to establish these relationships in individuals with voice disorders across the therapeutic process. PMID:25675090

  18. 1999 NASA High-Speed Research Program Aerodynamic Performance Workshop. Volume 2; High Lift

    NASA Technical Reports Server (NTRS)

    Hahne, David E. (Editor)

    1999-01-01

    The High-Speed Research Program sponsored the NASA High-Speed Research Program Aerodynamic Performance Review on February 8-12, 1999 in Anaheim, California. The review was designed to bring together NASA and industry High-Speed Civil Transport (HSCT) Aerodynamic Performance technology development participants in areas of: Configuration Aerodynamics (transonic and supersonic cruise drag prediction and minimization) and High-Lift. The review objectives were to: (1) report the progress and status of HSCT aerodynamic performance technology development; (2) disseminate this technology within the appropriate technical communities; and (3) promote synergy among the scientist and engineers working HSCT aerodynamics. The HSR AP Technical Review was held simultaneously with the annual review of the following airframe technology areas: Materials and Structures, Environmental Impact, Flight Deck, and Technology Integration Thus, a fourth objective of the Review was to promote synergy between the Aerodynamic Performance technology area and the other technology areas within the airframe element of the HSR Program. This Volume 2/Part 1 publication presents the High-Lift Configuration Development session.

  19. Energy Efficient Engine Low Pressure Subsystem Aerodynamic Analysis

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Delaney, Robert A.; Lynn, Sean R.; Veres, Joseph P.

    1998-01-01

    The objective of this study was to demonstrate the capability to analyze the aerodynamic performance of the complete low pressure subsystem (LPS) of the Energy Efficient Engine (EEE). Detailed analyses were performed using three- dimensional Navier-Stokes numerical models employing advanced clustered processor computing platforms. The analysis evaluates the impact of steady aerodynamic interaction effects between the components of the LPS at design and off- design operating conditions. Mechanical coupling is provided by adjusting the rotational speed of common shaft-mounted components until a power balance is achieved. The Navier-Stokes modeling of the complete low pressure subsystem provides critical knowledge of component acro/mechanical interactions that previously were unknown to the designer until after hardware testing.

  20. Inclusion of nonlinear aerodynamics in the FLAP code

    SciTech Connect

    Weber, T. )

    1989-11-01

    Horizontal axis wind turbines usually operate with significant portions of the blade in deep stall. This contradicts the assumption in the FLAP code that a linear relation exists between the angle of attack and the lift coefficient. The objective of this paper is to determine the importance of nonlinear aerodynamics in the prediction of loads. The FLAP code has been modified to include the nonlinear relationships between the lift and drag coefficients with the angle of attack. The modification affects the calculation of the induced velocities and the aerodynamic loads. This requires an iterative procedure to determine the induced velocities instead of a closed form solution. A more advanced tower interference model has also been added that accounts for both upwind and downwind tower effects. 7 refs., 14 figs.

  1. Bedside saccadometry as an objective and quantitative measure of hemisphere-specific neurological function in patients undergoing cranial surgery.

    PubMed

    Saleh, Y; Marcus, H J; Iorga, R; Nouraei, R; Carpenter, R H; Nandi, D

    2015-02-01

    Cranial surgery continues to carry a significant risk of neurological complications. New bedside tools that can objectively and quantitatively evaluate cerebral function may allow for earlier detection of such complications, more rapid initiation of therapy, and improved patient outcomes. We assessed the potential of saccadic eye movements as a measure of cerebral function in patients undergoing cranial surgery peri-operatively. Visually evoked saccades were measured in 20 patients before (-12 hours) and after (+2 and +5 days) undergoing cranial surgery. Hemisphere specific saccadic latencies were measured using a simple step-task and saccadic latency distributions were compared using the Kolmogorov-Smirnov test. Saccadic latency values were incorporated into an empirically validated mathematical model (Linear Approach to Threshold with Ergodic Rate [LATER] model) for further analysis (using Wilcoxon signed rank test). Thirteen males and seven females took part in our study (mean age 55 ± 4.9 years). Following cranial surgery, saccades initiated by the cerebral hemisphere on the operated side demonstrated significant deteriorations in function after 2 days (p < 0.01) that normalised after 5 days. Analysis using the LATER model confirmed these findings, highlighting decreased cerebral information processing as a potential mechanism for noted changes (p < 0.05). No patients suffered clinical complications after surgery. To conclude, bedside saccadometry can demonstrate hemisphere-specific changes after surgery in the absence of clinical symptoms. The LATER model confirms these findings and offers a mechanistic explanation for this change. Further work will be necessary to assess the practical validity of these changes in relation to clinical complications after surgery. PMID:25282394

  2. Integrated design and manufacturing for the high speed civil transport (a combined aerodynamics/propulsion optimization study)

    NASA Technical Reports Server (NTRS)

    Baecher, Juergen; Bandte, Oliver; DeLaurentis, Dan; Lewis, Kemper; Sicilia, Jose; Soboleski, Craig

    1995-01-01

    This report documents the efforts of a Georgia Tech High Speed Civil Transport (HSCT) aerospace student design team in completing a design methodology demonstration under NASA's Advanced Design Program (ADP). Aerodynamic and propulsion analyses are integrated into the synthesis code FLOPS in order to improve its prediction accuracy. Executing the integrated product and process development (IPPD) methodology proposed at the Aerospace Systems Design Laboratory (ASDL), an improved sizing process is described followed by a combined aero-propulsion optimization, where the objective function, average yield per revenue passenger mile ($/RPM), is constrained by flight stability, noise, approach speed, and field length restrictions. Primary goals include successful demonstration of the application of the response surface methodolgy (RSM) to parameter design, introduction to higher fidelity disciplinary analysis than normally feasible at the conceptual and early preliminary level, and investigations of relationships between aerodynamic and propulsion design parameters and their effect on the objective function, $/RPM. A unique approach to aircraft synthesis is developed in which statistical methods, specifically design of experiments and the RSM, are used to more efficiently search the design space for optimum configurations. In particular, two uses of these techniques are demonstrated. First, response model equations are formed which represent complex analysis in the form of a regression polynomial. Next, a second regression equation is constructed, not for modeling purposes, but instead for the purpose of optimization at the system level. Such an optimization problem with the given tools normally would be difficult due to the need for hard connections between the various complex codes involved. The statistical methodology presents an alternative and is demonstrated via an example of aerodynamic modeling and planform optimization for a HSCT.

  3. A saw is first identified as an object used on wood: ERP evidence for temporal differences between Thematic and Functional similarity relations.

    PubMed

    Wamain, Yannick; Pluciennicka, Ewa; Kalénine, Solène

    2015-05-01

    The role of functional and motor information in manipulable artifact object semantic organization is still poorly understood. In particular, several types of semantic relations involving object functional knowledge may be distinguished. Functional similarity relations group objects with similar functions at relatively specific (e.g. saw-axe, both used to cut wood) or general (saw-knife, both used to cut) levels. Thematic relations group objects based on their complementarity in events (saw used upon/with wood). Recent eye-tracking data showed distinct temporal time courses for the different semantic relations, with fastest processing of thematic relations and slowest processing of general function similarity relations. Behavioral data suggest the involvement of distinct cognitive mechanisms in manipulable artifact object semantic processing. The aim of the present study was to assess the neural correlates of thematic, and specific and general function similarity relation processing. Specifically, we investigated whether time course differences between semantic relations could be highlighted at the neurophysiological level. We used a protocol combining semantic priming with electroencephalography, and manipulated the type of semantic relation and the duration of the interval between prime and target objects. Two consistent and complementary results were shown. On N1 and P3 components, semantic priming was observed for thematic relations only. On N400 component, the type of semantic relation interacted with interval duration, and semantic priming was visible for all 3 relations after the longest interval only. Results revealed graded processing time courses for thematic, specific function similarity, and general function similarity relations at the neural level, and further indicate that thematic relations impact object processing during the early stages of object recognition. Findings suggest a hierarchical organization of three types of semantic relations based on

  4. A PDE Sensitivity Equation Method for Optimal Aerodynamic Design

    NASA Technical Reports Server (NTRS)

    Borggaard, Jeff; Burns, John

    1996-01-01

    The use of gradient based optimization algorithms in inverse design is well established as a practical approach to aerodynamic design. A typical procedure uses a simulation scheme to evaluate the objective function (from the approximate states) and its gradient, then passes this information to an optimization algorithm. Once the simulation scheme (CFD flow solver) has been selected and used to provide approximate function evaluations, there are several possible approaches to the problem of computing gradients. One popular method is to differentiate the simulation scheme and compute design sensitivities that are then used to obtain gradients. Although this black-box approach has many advantages in shape optimization problems, one must compute mesh sensitivities in order to compute the design sensitivity. In this paper, we present an alternative approach using the PDE sensitivity equation to develop algorithms for computing gradients. This approach has the advantage that mesh sensitivities need not be computed. Moreover, when it is possible to use the CFD scheme for both the forward problem and the sensitivity equation, then there are computational advantages. An apparent disadvantage of this approach is that it does not always produce consistent derivatives. However, for a proper combination of discretization schemes, one can show asymptotic consistency under mesh refinement, which is often sufficient to guarantee convergence of the optimal design algorithm. In particular, we show that when asymptotically consistent schemes are combined with a trust-region optimization algorithm, the resulting optimal design method converges. We denote this approach as the sensitivity equation method. The sensitivity equation method is presented, convergence results are given and the approach is illustrated on two optimal design problems involving shocks.

  5. Stress inversion of heterogeneous fault-slip data with unknown slip sense: An objective function algorithm contouring method

    NASA Astrophysics Data System (ADS)

    Hansen, John-Are; Bergh, Steffen G.; Osmundsen, Per Terje; Redfield, Tim F.

    2015-01-01

    We propose a new method for stress inversion and separation of principal stress states from heterogeneous fault-slip data. The method is semi-automatic, and is based on the moment method of stress inversion (Fry 1999) in combination with the objective function algorithm (OFA) for stress separation (Shan et al 2003). In the presented routine we randomly partition the heterogeneous fault-slip dataset into subsets ranging between one and six. The number of subsets K represents the number of possible mixed stress states in the fault-slip dataset. For each partition number K, we run the OFA 1000 times. Following this we plot and contour the principal stress axes, corresponding to the minimum value of the objective function for each run, in a stereonet. By evaluating how solution clusters of principal stress axes change with increasing number of subsets K, we are able to determine the number of mixed stress states and their optimal solutions for heterogeneous fault-slip datasets. While the numbers of subsets are underestimated, solution-clusters of principal stress axes represent average stress states. However, once the correct number of subsets is reached, solution clusters align with the slip-generating principal stress axes. The solution clusters then become stable, and overestimating the number of subsets does not significantly alter their orientation. The partition number K when stability is obtained thus determines the number of mixed stress states in the heterogeneous dataset, while the corresponding highest density solution clusters give the best estimate of the slip-generating principal stress axes and corresponding stress shape ratios. The inversion routine is tested and confirmed using synthetic data and fault-slip data from the Gullkista fault in Northern Norway. Because the stress calculation is based on the moment method, the inversion routine is insensitive to the correct assessment of slip sense, and only requires the slip vector and orientation of the

  6. ASSOCIATION BETWEEN THYROID FUNCTION AND OBJECTIVE AND SUBJECTIVE SLEEP QUALITY IN OLDER MEN: THE OSTEOPOROTIC FRACTURES IN MEN (MROS) STUDY

    PubMed Central

    Akatsu, Haruko; Ewing, Susan K.; Stefanick, Marcia L.; Fink, Howard A.; Stone, Katie L.; Barrett-Connor, Elizabeth; Mehra, Reena; Ancoli-Israel, Sonia; Redline, Susan; Hoffman, Andrew R.

    2014-01-01

    Objective To determine the association between thyroid hormone levels and sleep quality in community-dwelling men. Methods Among 5,994 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) study, 682 had baseline thyroid function data, normal free thyroxine (FT4) (0.70 ≤ FT4 ≤ 1.85 ng/dL), actigraphy measurements, and were not using thyroid-related medications. Three categories of thyroid function were defined: subclinical hyperthyroid, thyroid-stimulating hormone (TSH) <0.55 mIU/L; euthyroid (TSH, 0.55 to 4.78 mIU/L); and subclinical hypothyroid (TSH >4.78 mIU/L). Objective (total hours of nighttime sleep [TST], sleep efficiency [SE], wake after sleep onset [WASO], sleep latency [SL], number of long wake episodes [LWEP]) and subjective (TST, Pittsburgh Sleep Quality Index score, Epworth Sleepiness Scale score) sleep quality were measured. The association between TSH and sleep quality was examined using linear regression (continuous sleep outcomes) and log-binomial regression (categorical sleep outcomes). Results Among the 682 men examined, 15 had subclinical hyperthyroidism and 38 had subclinical hypothyroidism. There was no difference in sleep quality between subclinical hypothyroid and euthyroid men. Compared to euthyroid men, subclinical hyperthyroid men had lower mean actigraphy TST (adjusted mean difference [95% confidence interval (CI)], −27.4 [−63.7 to 8.9] minutes) and lower mean SE (−4.5% [−10.3% to 1.3%]), higher mean WASO (13.5 [−8.0 to 35.0] minutes]), whereas 41% had increased risk of actigraphy-measured TST <6 hours (relative risk [RR], 1.41; 95% CI, 0.83 to 2.39), and 83% had increased risk of SL ≥60 minutes (RR, 1.83; 95% CI, 0.65 to 5.14) (all P>0.05). Conclusion Neither subclinical hypothyroidism nor hyperthyroidism is significantly associated with decreased sleep quality. PMID:24449663

  7. Image processing of aerodynamic data

    NASA Technical Reports Server (NTRS)

    Faulcon, N. D.

    1985-01-01

    The use of digital image processing techniques in analyzing and evaluating aerodynamic data is discussed. An image processing system that converts images derived from digital data or from transparent film into black and white, full color, or false color pictures is described. Applications to black and white images of a model wing with a NACA 64-210 section in simulated rain and to computed low properties for transonic flow past a NACA 0012 airfoil are presented. Image processing techniques are used to visualize the variations of water film thicknesses on the wing model and to illustrate the contours of computed Mach numbers for the flow past the NACA 0012 airfoil. Since the computed data for the NACA 0012 airfoil are available only at discrete spatial locations, an interpolation method is used to provide values of the Mach number over the entire field.

  8. The basic aerodynamics of floatation

    NASA Astrophysics Data System (ADS)

    Davies, M. J.; Wood, D. H.

    1983-09-01

    It is pointed out that the basic aerodynamics of modern floatation ovens, in which the continuous, freshly painted metal strip is floated, dried, and cured, is the two-dimensional analog of that of hovercraft. The basic theory for the static lift considered in connection with the study of hovercraft has had spectacular success in describing the experimental results. This appears surprising in view of the crudity of the theory. The present investigation represents an attempt to explore the reasons for this success. An outline of the basic theory is presented and an approach is shown for deriving the resulting expressions for the lift from the full Navier-Stokes equations in a manner that clearly indicates the limitations on the validity of the expressions. Attention is given to the generally good agreement between the theory and the axisymmetric (about the centerline) results reported by Jaumotte and Kiedrzynski (1965).

  9. Rarefaction Effects in Hypersonic Aerodynamics

    NASA Astrophysics Data System (ADS)

    Riabov, Vladimir V.

    2011-05-01

    The Direct Simulation Monte-Carlo (DSMC) technique is used for numerical analysis of rarefied-gas hypersonic flows near a blunt plate, wedge, two side-by-side plates, disk, torus, and rotating cylinder. The role of various similarity parameters (Knudsen and Mach numbers, geometrical and temperature factors, specific heat ratios, and others) in aerodynamics of the probes is studied. Important kinetic effects that are specific for the transition flow regime have been found: non-monotonic lift and drag of plates, strong repulsive force between side-by-side plates and cylinders, dependence of drag on torus radii ratio, and the reverse Magnus effect on the lift of a rotating cylinder. The numerical results are in a good agreement with experimental data, which were obtained in a vacuum chamber at low and moderate Knudsen numbers from 0.01 to 10.

  10. Aerodynamic research on tipvane windturbines

    NASA Astrophysics Data System (ADS)

    Vanbussel, G. J. W.; Vanholten, T.; Vankuik, G. A. M.

    1982-09-01

    Tipvanes are small auxiliary wings mounted at the tips of windturbine blades in such a way that a diffuser effect is generated, resulting in a mass flow augmentation through the turbine disc. For predicting aerodynamic loads on the tipvane wind turbine, the acceleration potential is used and an expansion method is applied. In its simplest form, this method can essentially be classified as a lifting line approach, however, with a proper choice of the basis load distributions of the lifting line, the numerical integration of the pressurefield becomes one dimensional. the integration of the other variable can be performed analytically. The complete analytical expression for the pressure field consists of two series of basic pressure fields. One series is related to the basic load distributions over the turbineblade, and the other series to the basic load distribution over the tipvane.

  11. Aerodynamic seals for rotary machine

    DOEpatents

    Bidkar, Rahul Anil; Cirri, Massimiliano; Thatte, Azam Mihir; Williams, John Robert

    2016-02-09

    An aerodynamic seal assembly for a rotary machine includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the segments includes a shoe plate with a forward-shoe section and an aft-shoe section having multiple labyrinth teeth therebetween facing the rotor. The sealing device segment also includes multiple flexures connected to the shoe plate and to a top interface element, wherein the multiple flexures are configured to allow the high pressure fluid to occupy a forward cavity and the low pressure fluid to occupy an aft cavity. Further, the sealing device segments include a secondary seal attached to the top interface element at one first end and positioned about the flexures and the shoe plate at one second end.

  12. On Cup Anemometer Rotor Aerodynamics

    PubMed Central

    Pindado, Santiago; Pérez, Javier; Avila-Sanchez, Sergio

    2012-01-01

    The influence of anemometer rotor shape parameters, such as the cups' front area or their center rotation radius on the anemometer's performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups' center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor's cup. PMID:22778638

  13. Validation of Methodology for Estimating Aircraft Unsteady Aerodynamic Parameters from Dynamic Wind Tunnel Tests

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.; Klein, Vladislav

    2003-01-01

    A basic problem in flight dynamics is the mathematical formulation of the aerodynamic model for aircraft. This study is part of an ongoing effort at NASA Langley to develop a more general formulation of the aerodynamic model for aircraft that includes nonlinear unsteady aerodynamics and to develop appropriate test techniques that facilitate identification of these models. A methodology for modeling and testing using wide-band inputs to estimate the unsteady form of the aircraft aerodynamic model was developed previously but advanced test facilities were not available at that time to allow complete validation of the methodology. The new model formulation retained the conventional static and rotary dynamic terms but replaced conventional acceleration terms with more general indicial functions. In this study advanced testing techniques were utilized to validate the new methodology for modeling. Results of static, conventional forced oscillation, wide-band forced oscillation, oscillatory coning, and ramp tests are presented.

  14. Aerodynamic Noise Generated by Shinkansen Cars

    NASA Astrophysics Data System (ADS)

    KITAGAWA, T.; NAGAKURA, K.

    2000-03-01

    The noise value (A -weighted sound pressure level, SLOW) generated by Shinkansen trains, now running at 220-300 km/h, should be less than 75 dB(A) at the trackside. Shinkansen noise, such as rolling noise, concrete support structure noise, and aerodynamic noise are generated by various parts of Shinkansen trains. Among these aerodynamic noise is important because it is the major contribution to the noise generated by the coaches running at high speed. In order to reduce the aerodynamic noise, a number of improvements to coaches have been made. As a result, the aerodynamic noise has been reduced, but it still remains significant. In addition, some aerodynamic noise generated from the lower parts of cars remains. In order to investigate the contributions of these noises, a method of analyzing Shinkansen noise has been developed and applied to the measured data of Shinkansen noise at speeds between 120 and 315 km/h. As a result, the following conclusions have been drawn: (1) Aerodynamic noise generated from the upper parts of cars was reduced considerably by smoothing car surfaces. (2) Aerodynamic noise generated from the lower parts of cars has a major influence upon the wayside noise.

  15. Training Data Requirement for a Neural Network to Predict Aerodynamic Coefficients

    NASA Technical Reports Server (NTRS)

    Korsmeyer, David (Technical Monitor); Rajkumar, T.; Bardina, Jorge

    2003-01-01

    Basic aerodynamic coefficients are modeled as functions of angle of attack, speed brake deflection angle, Mach number, and side slip angle. Most of the aerodynamic parameters can be well-fitted using polynomial functions. We previously demonstrated that a neural network is a fast, reliable way of predicting aerodynamic coefficients. We encountered few under fitted and/or over fitted results during prediction. The training data for the neural network are derived from wind tunnel test measurements and numerical simulations. The basic questions that arise are: how many training data points are required to produce an efficient neural network prediction, and which type of transfer functions should be used between the input-hidden layer and hidden-output layer. In this paper, a comparative study of the efficiency of neural network prediction based on different transfer functions and training dataset sizes is presented. The results of the neural network prediction reflect the sensitivity of the architecture, transfer functions, and training dataset size.

  16. STEP and STEPSPL: Computer programs for aerodynamic model structure determination and parameter estimation

    NASA Technical Reports Server (NTRS)

    Batterson, J. G.

    1986-01-01

    The successful parametric modeling of the aerodynamics for an airplane operating at high angles of attack or sideslip is performed in two phases. First the aerodynamic model structure must be determined and second the associated aerodynamic parameters (stability and control derivatives) must be estimated for that model. The purpose of this paper is to document two versions of a stepwise regression computer program which were developed for the determination of airplane aerodynamic model structure and to provide two examples of their use on computer generated data. References are provided for the application of the programs to real flight data. The two computer programs that are the subject of this report, STEP and STEPSPL, are written in FORTRAN IV (ANSI l966) compatible with a CDC FTN4 compiler. Both programs are adaptations of a standard forward stepwise regression algorithm. The purpose of the adaptation is to facilitate the selection of a adequate mathematical model of the aerodynamic force and moment coefficients of an airplane from flight test data. The major difference between STEP and STEPSPL is in the basis for the model. The basis for the model in STEP is the standard polynomial Taylor's series expansion of the aerodynamic function about some steady-state trim condition. Program STEPSPL utilizes a set of spline basis functions.

  17. Influence of a humidor on the aerodynamics of baseballs

    NASA Astrophysics Data System (ADS)

    Meyer, Edmund R.; Bohn, John L.

    2008-11-01

    We investigate whether storing baseballs in a controlled humidity environment significantly affects their aerodynamic properties. We measure the change in diameter and weight of baseballs as a function of relative humidity in which the balls are stored. The trajectories of pitched and batted baseballs are modeled to assess the difference between those stored at 30% relative humidity versus 50% relative humidity. We find that a drier baseball will curve slightly more than a humidified one for a given pitch velocity and rotation rate. We also find that aerodynamics alone would add 2ft to the distance a wetter baseball ball is hit. This increased distance is compensated by a 6ft reduction in the batted distance due to the change in the coefficient of restitution of the ball. We discuss consequences of these results for baseball played at Coors Field in Denver, where baseballs have been stored in a humidor at 50% relative humidity since 2002.

  18. General Theory of Aerodynamic Instability and the Mechanism of Flutter

    NASA Technical Reports Server (NTRS)

    Theodorsen, Theodore

    1949-01-01

    The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Bessel functions of the first and second kind and of zero and first order. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-section theory relating to the steady case. The air forces being known, the mechanism of aerodynamic instability has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been arrived at. The solution is of a simple form and is expressed by means of an auxiliary parameter K.

  19. Grid Sensitivity and Aerodynamic Optimization of Generic Airfoils

    NASA Technical Reports Server (NTRS)

    Sadrehaghighi, Ideen; Smith, Robert E.; Tiwari, Surendra N.

    1995-01-01

    An algorithm is developed to obtain the grid sensitivity with respect to design parameters for aerodynamic optimization. The procedure is advocating a novel (geometrical) parameterization using spline functions such as NURBS (Non-Uniform Rational B- Splines) for defining the airfoil geometry. An interactive algebraic grid generation technique is employed to generate C-type grids around airfoils. The grid sensitivity of the domain with respect to geometric design parameters has been obtained by direct differentiation of the grid equations. A hybrid approach is proposed for more geometrically complex configurations such as a wing or fuselage. The aerodynamic sensitivity coefficients are obtained by direct differentiation of the compressible two-dimensional thin-layer Navier-Stokes equations. An optimization package has been introduced into the algorithm in order to optimize the airfoil surface. Results demonstrate a substantially improved design due to maximized lift/drag ratio of the airfoil.

  20. Impaired functional differentiation for categories of objects in the ventral visual stream: A case of developmental visual impairment.

    PubMed

    Martinaud, Olivier; Pouliquen, Dorothée; Parain, Dominique; Goldenberg, Alice; Gérardin, Emmanuel; Hannequin, Didier; Altarelli, Irène; Ramus, Franck; Hertz-Pannier, Lucie; Dehaene-Lambertz, Ghislaine; Cohen, Laurent

    2015-10-01

    We report the case of a 14-year-old girl suffering from severe developmental visual impairment along with delayed language and cognitive development, and featuring a clear-cut dissociation between spared dorsal and impaired ventral visual pathways. Visual recognition of objects, including faces and printed words, was affected. In contrast, movement perception and visually guided motor control were preserved. Structural MRI was normal on inspection, but Voxel Based Morphometry (VBM) revealed reduced grey matter density in the mesial occipital and ventral occipito-temporal cortex. Functional MRI during the perception of line drawings uncovered impaired differentiation which is normally observed at even younger ages: no local category preferences could be identified within the occipito-temporal cortex for faces, houses, words or tools. In contrast, movement-related activations appeared to be normal. Finally, those abnormalities evolved on the background of chronic bilateral occipital epileptic activity, including continuous spike-wave discharges during sleep, which may be considered as the primary cause of non-specific intellectual disability and visual impairment. PMID:26272240

  1. Using expected allele number as objective function to design between and within breed conservation of farm animal biodiversity.

    PubMed

    Simianer, H

    2005-06-01

    Conservation of genetic diversity in farm animal species can be achieved by preventing extinction of breeds and by reducing genetic drift within breeds. It is suggested to use the expected number of alleles segregating in the species after a given time period as objective function in the design of conservation strategies. A formal approach is presented to predict this quantity based on marker information, accounting for extinction probability of breeds and effective population size within breeds as the major component of genetic drift. Based on this model, relative efficiency of different strategies of diversity conservation can be quantified. Formulas are given to derive the marginal expected number of alleles with respect to genetic drift within population and extinction probability, respectively. The suggested approach is illustrated with an example of 13 European cattle breeds. With the assumed parameters, drift is shown to be the major force leading to loss of alleles, and different breeds are prioritized for activities to reduce risk of extinction and for measures to reduce genetic drift, respectively. Although different aspects of the model need to be further refined, the suggested methodology provides a general and flexible tool to derive the optimum conservation strategy in various scenarios. PMID:16130469

  2. A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL).

    PubMed

    Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

    2015-01-01

    In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds. PMID:26266411

  3. A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL)

    PubMed Central

    Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

    2015-01-01

    In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds. PMID:26266411

  4. Is Motion Extrapolation Employed in Multiple Object Tracking?: Tracking as a Low-Level, Non-Predictive Function

    ERIC Educational Resources Information Center

    Keane, Brian P.; Pylyshyn, Zenon W.

    2006-01-01

    In a series of five experiments, we investigated whether visual tracking mechanisms utilize prediction when recovering multiple reappearing objects. When all objects abruptly disappeared and reappeared mid-trajectory, it was found that (a) subjects tracked better when objects reappeared at their loci of disappearance than when they reappeared in…

  5. Transpiration Control Of Aerodynamics Via Porous Surfaces

    NASA Technical Reports Server (NTRS)

    Banks, Daniel W.; Wood, Richard M.; Bauer, Steven X. S.

    1993-01-01

    Quasi-active porous surface used to control pressure loading on aerodynamic surface of aircraft or other vehicle, according to proposal. In transpiration control, one makes small additions of pressure and/or mass to cavity beneath surface of porous skin on aerodynamic surface, thereby affecting rate of transpiration through porous surface. Porous skin located on forebody or any other suitable aerodynamic surface, with cavity just below surface. Device based on concept extremely lightweight, mechanically simple, occupies little volume in vehicle, and extremely adaptable.

  6. Identification of aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Lan, C. Edward; Hu, C. C.

    1992-01-01

    The method based on Fourier functional analysis and indicial formulation for aerodynamic modeling as proposed by Chin and Lan is extensively examined and improved for the purpose of general applications to realistic airplane configurations. Improvement is made to automate the calculation of model coefficients, and to evaluate more accurately the indicial integral. Test data of large angle-of-attack ranges for two different models, a 70 deg. delta wing and an F-18 model, are used to further verify the applicability of Fourier functional analysis and validate the indicial formulation. The results show that the general expression for harmonic motions throughout a range of k is capable of accurately modeling the nonlinear responses with large phase lag except in the region where an inconsistent hysteresis behavior from one frequency to the other occurs. The results by the indicial formulation indicate that more accurate results can be obtained when the motion starts from a low angle of attack where hysteresis effect is not important.

  7. Aerodynamic Optimization of Supersonic Transport at Near-Sonic Regime

    NASA Astrophysics Data System (ADS)

    Yamazaki, Wataru; Matsushima, Kisa; Obayashi, Shigeru; Nakahashi, Kazuhiro

    Recently, an airplane cruising at near-sonic regime is watched with keen interest. The Sonic-Cruiser, of which the Boeing Company has examined and challenged the development, is the most remarkable case. In this paper, motivated by this trend, aerodynamic performance optimization for an airplane cruising at near-sonic regime is discussed based on CFD simulations. NAL’s experimental supersonic airplane, called NEXST-1, was employed as the baseline model for optimization. Aerodynamic performance was evaluated by solving the Euler equations with the unstructured grid method. It was confirmed that the performance Euler simulation predicted was qualitatively correct. By the evaluation to select a baseline model for optimization, NEXST-1 was accepted as a candidate of sonic plane because of the existence of drag bucket at near-sonic regime. In the optimization, Genetic Algorithm was used with Euler simulations. The objective was to reduce drag keeping lift constant, at the flying speed of Mach 0.98. The optimized result showed L/D improvement not only for near-sonic regime but also for transonic regime. The mechanism of design to reduce drag force was found through the analysis and comparison of the geometries and aerodynamic phenomena about the baseline model and the optimized one.

  8. Using the HARV simulation aerodynamic model to determine forebody strake aerodynamic coefficients from flight data

    NASA Technical Reports Server (NTRS)

    Messina, Michael D.

    1995-01-01

    The method described in this report is intended to present an overview of a process developed to extract the forebody aerodynamic increments from flight tests. The process to determine the aerodynamic increments (rolling pitching, and yawing moments, Cl, Cm, Cn, respectively) for the forebody strake controllers added to the F/A - 18 High Alpha Research Vehicle (HARV) aircraft was developed to validate the forebody strake aerodynamic model used in simulation.

  9. DOE Project on Heavy Vehicle Aerodynamic Drag

    SciTech Connect

    McCallen, R; Salari, K; Ortega, J; Castellucci, P; Pointer, D; Browand, F; Ross, J; Storms, B

    2007-01-04

    Class 8 tractor-trailers consume 11-12% of the total US petroleum use. At highway speeds, 65% of the energy expenditure for a Class 8 truck is in overcoming aerodynamic drag. The project objective is to improve fuel economy of Class 8 tractor-trailers by providing guidance on methods of reducing drag by at least 25%. A 25% reduction in drag would present a 12% improvement in fuel economy at highway speeds, equivalent to about 130 midsize tanker ships per year. Specific goals include: (1) Provide guidance to industry in the reduction of aerodynamic drag of heavy truck vehicles; (2) Develop innovative drag reducing concepts that are operationally and economically sound; and (3) Establish a database of experimental, computational, and conceptual design information, and demonstrate the potential of new drag-reduction devices. The studies described herein provide a demonstration of the applicability of the experience developed in the analysis of the standard configuration of the Generic Conventional Model. The modeling practices and procedures developed in prior efforts have been applied directly to the assessment of new configurations including a variety of geometric modifications and add-on devices. Application to the low-drag 'GTS' configuration of the GCM has confirmed that the error in predicted drag coefficients increases as the relative contribution of the base drag resulting from the vehicle wake to the total drag increases and it is recommended that more advanced turbulence modeling strategies be applied under those circumstances. Application to a commercially-developed boat tail device has confirmed that this restriction does not apply to geometries where the relative contribution of the base drag to the total drag is reduced by modifying the geometry in that region. Application to a modified GCM geometry with an open grille and radiator has confirmed that the underbody flow, while important for underhood cooling, has little impact on the drag coefficient of

  10. Aerodynamic Characteristics and Development of the Aerodynamic Database of the X-34 Reusable Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Pamadi , Bandu N.; Brauckmann, Gregory J.

    1999-01-01

    An overview of the aerodynamic characteristics and the process of developing the preflight aerodynamic database of the NASA/ Orbital X-34 reusable launch vehicle is presented in this paper. Wind tunnel tests from subsonic to hypersonic Mach numbers including ground effect tests at low subsonic speeds were conducted in various facilities at the NASA Langley Research Center. The APAS (Aerodynamic Preliminary Analysis System) code was used for engineering level analysis and to fill the gaps in the wind tunnel test data. This aerodynamic database covers the range of Mach numbers, angles of attack, sideslip and control surface deflections anticipated in the complete flight envelope.

  11. HSR Aerodynamic Performance Status and Challenges

    NASA Technical Reports Server (NTRS)

    Gilbert, William P.; Antani, Tony; Ball, Doug; Calloway, Robert L.; Snyder, Phil

    1999-01-01

    This paper describes HSR (High Speed Research) Aerodynamic Performance Status and Challenges. The topics include: 1) Aero impact on HSR; 2) Goals and Targets; 3) Progress and Status; and 4) Remaining Challenges. This paper is presented in viewgraph form.

  12. Aerodynamic analysis of Pegasus - Computations vs reality

    NASA Technical Reports Server (NTRS)

    Mendenhall, Michael R.; Lesieutre, Daniel J.; Whittaker, C. H.; Curry, Robert E.; Moulton, Bryan

    1993-01-01

    Pegasus, a three-stage, air-launched, winged space booster was developed to provide fast and efficient commercial launch services for small satellites. The aerodynamic design and analysis of Pegasus was conducted without benefit of wind tunnel tests using only computational aerodynamic and fluid dynamic methods. Flight test data from the first two operational flights of Pegasus are now available, and they provide an opportunity to validate the accuracy of the predicted pre-flight aerodynamic characteristics. Comparisons of measured and predicted flight characteristics are presented and discussed. Results show that the computational methods provide reasonable aerodynamic design information with acceptable margins. Post-flight analyses illustrate certain areas in which improvements are desired.

  13. Switchable and Tunable Aerodynamic Drag on Cylinders

    NASA Astrophysics Data System (ADS)

    Guttag, Mark; Lopez Jimenez, Francisco; Reis, Pedro

    2015-11-01

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, which are thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  14. Switchable and Tunable Aerodynamic Drag on Cylinders

    NASA Astrophysics Data System (ADS)

    Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  15. Aerodynamics and performance testing of the VAWT

    SciTech Connect

    Klimas, P.C.

    1981-01-01

    Early investigations suggest that reductions in cost of energy (COE) and increases in reliability for VAWT systems may be brought about through relatively inexpensive changes to the current aerodynamic design. This design uses blades of symmetrical cross-section mounted such that the radius from the rotating tower centerline is normal to the blade chord at roughly the 40% chord point. The envisioned changes to this existing design are intended to: (1) lower cut-in windspeed; (2) increase maximum efficiency; (3) limit maximum aerodynamic power; and (4) limit peak aerodynamic torques. This paper describes certain experiments designed to both better understand the aerodynamics of a section operating in an unsteady, curvilinear flowfield and achieve some of the desired changes in section properties. The common goal of all of these experiments is to lower VAWT COE and increase system reliability.

  16. Aerodynamic Characterization of a Modern Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Hall, Robert M.; Holland, Scott D.; Blevins, John A.

    2011-01-01

    A modern launch vehicle is by necessity an extremely integrated design. The accurate characterization of its aerodynamic characteristics is essential to determine design loads, to design flight control laws, and to establish performance. The NASA Ares Aerodynamics Panel has been responsible for technical planning, execution, and vetting of the aerodynamic characterization of the Ares I vehicle. An aerodynamics team supporting the Panel consists of wind tunnel engineers, computational engineers, database engineers, and other analysts that address topics such as uncertainty quantification. The team resides at three NASA centers: Langley Research Center, Marshall Space Flight Center, and Ames Research Center. The Panel has developed strategies to synergistically combine both the wind tunnel efforts and the computational efforts with the goal of validating the computations. Selected examples highlight key flow physics and, where possible, the fidelity of the comparisons between wind tunnel results and the computations. Lessons learned summarize what has been gleaned during the project and can be useful for other vehicle development projects.

  17. Aerodynamic Analyses Requiring Advanced Computers, Part 1

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Papers are presented which deal with results of theoretical research on aerodynamic flow problems requiring the use of advanced computers. Topics discussed include: viscous flows, boundary layer equations, turbulence modeling and Navier-Stokes equations, and internal flows.

  18. Hypervelocity Free-Flight Aerodynamic Facility (HFFAF)

    NASA Video Gallery

    The HFFAF is the only aeroballistic range the nation currently capable of testing in gases other than air and at sub-atmospheric pressures. It is used primarily to study the aerodynamics, Aerotherm...

  19. Aerodynamic Analyses Requiring Advanced Computers, part 2

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Papers given at the conference present the results of theoretical research on aerodynamic flow problems requiring the use of advanced computers. Topics discussed include two-dimensional configurations, three-dimensional configurations, transonic aircraft, and the space shuttle.

  20. The oscillating wing with aerodynamically balanced elevator

    NASA Technical Reports Server (NTRS)

    Kussner, H G; Schwartz, I

    1941-01-01

    The two-dimensional problem of the oscillating wing with aerodynamically balanced elevator is treated in the manner that the wing is replaced by a plate with bends and stages and the airfoil section by a mean line consisting of one or more straights. The computed formulas and tables permit, on these premises, the prediction of the pressure distribution and of the aerodynamic reactions of oscillating elevators and tabs with any position of elevator hinge in respect to elevator leading edge.

  1. Means for controlling aerodynamically induced twist

    NASA Technical Reports Server (NTRS)

    Elber, W. (Inventor)

    1982-01-01

    A control mechanism which provides active compensation for aerodynamically induced twist deformation of high aspect ratio wings consists of a torque tube, internal to each wing and rigidly attached near the tip of each wing, which is moved by an actuator located in the aircraft fuselage. As changes in the aerodynamic loads on the wings occur the torque tube is rotated to compensate for the induced wing twist.

  2. Bayesian inference of nonlinear unsteady aerodynamics from aeroelastic limit cycle oscillations

    NASA Astrophysics Data System (ADS)

    Sandhu, Rimple; Poirel, Dominique; Pettit, Chris; Khalil, Mohammad; Sarkar, Abhijit

    2016-07-01

    A Bayesian model selection and parameter estimation algorithm is applied to investigate the influence of nonlinear and unsteady aerodynamic loads on the limit cycle oscillation (LCO) of a pitching airfoil in the transitional Reynolds number regime. At small angles of attack, laminar boundary layer trailing edge separation causes negative aerodynamic damping leading to the LCO. The fluid-structure interaction of the rigid, but elastically mounted, airfoil and nonlinear unsteady aerodynamics is represented by two coupled nonlinear stochastic ordinary differential equations containing uncertain parameters and model approximation errors. Several plausible aerodynamic models with increasing complexity are proposed to describe the aeroelastic system leading to LCO. The likelihood in the posterior parameter probability density function (pdf) is available semi-analytically using the extended Kalman filter for the state estimation of the coupled nonlinear structural and unsteady aerodynamic model. The posterior parameter pdf is sampled using a parallel and adaptive Markov Chain Monte Carlo (MCMC) algorithm. The posterior probability of each model is estimated using the Chib-Jeliazkov method that directly uses the posterior MCMC samples for evidence (marginal likelihood) computation. The Bayesian algorithm is validated through a numerical study and then applied to model the nonlinear unsteady aerodynamic loads using wind-tunnel test data at various Reynolds numbers.

  3. Sensitivity Analysis and Optimization of Aerodynamic Configurations with Blend Surfaces

    NASA Technical Reports Server (NTRS)

    Thomas, A. M.; Tiwari, S. N.

    1997-01-01

    A novel (geometrical) parametrization procedure using solutions to a suitably chosen fourth order partial differential equation is used to define a class of airplane configurations. Inclusive in this definition are surface grids, volume grids, and grid sensitivity. The general airplane configuration has wing, fuselage, vertical tail and horizontal tail. The design variables are incorporated into the boundary conditions, and the solution is expressed as a Fourier series. The fuselage has circular cross section, and the radius is an algebraic function of four design parameters and an independent computational variable. Volume grids are obtained through an application of the Control Point Form method. A graphic interface software is developed which dynamically changes the surface of the airplane configuration with the change in input design variable. The software is made user friendly and is targeted towards the initial conceptual development of any aerodynamic configurations. Grid sensitivity with respect to surface design parameters and aerodynamic sensitivity coefficients based on potential flow is obtained using an Automatic Differentiation precompiler software tool ADIFOR. Aerodynamic shape optimization of the complete aircraft with twenty four design variables is performed. Unstructured and structured volume grids and Euler solutions are obtained with standard software to demonstrate the feasibility of the new surface definition.

  4. Aerodynamic design optimization by using a continuous adjoint method

    NASA Astrophysics Data System (ADS)

    Luo, JiaQi; Xiong, JunTao; Liu, Feng

    2014-07-01

    This paper presents the fundamentals of a continuous adjoint method and the applications of this method to the aerodynamic design optimization of both external and internal flows. General formulation of the continuous adjoint equations and the corresponding boundary conditions are derived. With the adjoint method, the complete gradient information needed in the design optimization can be obtained by solving the governing flow equations and the corresponding adjoint equations only once for each cost function, regardless of the number of design parameters. An inverse design of airfoil is firstly performed to study the accuracy of the adjoint gradient and the effectiveness of the adjoint method as an inverse design method. Then the method is used to perform a series of single and multiple point design optimization problems involving the drag reduction of airfoil, wing, and wing-body configuration, and the aerodynamic performance improvement of turbine and compressor blade rows. The results demonstrate that the continuous adjoint method can efficiently and significantly improve the aerodynamic performance of the design in a shape optimization problem.

  5. Atmospheric tests of trailing-edge aerodynamic devices

    SciTech Connect

    Miller, L S; Huang, S; Quandt, G A

    1998-01-01

    An experiment was conducted at the National Renewable Energy Laboratory`s (NREL`s) National Wind Technology Center (NWTC) using an instrumented horizontal-axis wind turbine that incorporated variable-span, trailing-edge aerodynamic brakes. The goal of the investigation was to directly compare results with (infinite-span) wind tunnel data and to provide information on how to account for device span effects during turbine design or analysis. Comprehensive measurements were used to define effective changes in the aerodynamic and hinge-moment coefficients, as a function of angle of attack and control deflection, for three device spans (7.5%, 15%, and 22.5%) and configurations (Spoiler-Flap, vented sileron, and unvented aileron). Differences in the lift and drag behavior are most pronounced near stall and for device spans of less than 15%. Drag performance is affected only minimally (about a 30% reduction from infinite-span) for 15% or larger span devices. Interestingly, aerodynamic controls with vents or openings appear most affected by span reductions and three-dimensional flow.

  6. Aerodynamic characteristics of sixteen electric, hybrid, and subcompact vehicles

    NASA Technical Reports Server (NTRS)

    Kurtz, D. W.

    1979-01-01

    An elementary electric and hybrid vehicle aerodynamic data base was developed using data obtained on sixteen electric, hybrid, and sub-compact production vehicles tested in the Lockheed-Georgia low-speed wind tunnel. Zero-yaw drag coefficients ranged from a high of 0.58 for a boxey delivery van and an open roadster to a low of about 0.34 for a current four-passenger proto-type automobile which was designed with aerodynamics as an integrated parameter. Vehicles were tested at yaw angles up to 40 degrees and a wing weighting analysis is presented which yields a vehicle's effective drag coefficient as a function of wing velocity and driving cycle. Other parameters investigated included the effects of windows open and closed, radiators open and sealed, and pop-up headlights. Complete six-component force and moment data are presented in both tabular and graphical formats. Only limited commentary is offered since, by its very nature, a data base should consist of unrefined reference material. A justification for pursuing efficient aerodynamic design of EHVs is presented.

  7. Darrieus rotor aerodynamics in turbulent wind

    SciTech Connect

    Brahimi, M.T.; Paraschivoiu, I.

    1995-05-01

    The earlier aerodynamic models for studying vertical axis wind turbines (VAWT`s) are based on constant incident wind conditions and are thus capable of predicting only periodic variations in the loads. The purpose of the present study is to develop a model capable of predicting the aerodynamic loads on the Darrieus rotor in a turbulent wind. This model is based on the double-multiple streamtube method (DMS) and incorporates a stochastic wind model. The method used to simulate turbulent velocity fluctuations is based on the power spectral density. The problem consists in generating a region of turbulent flow with a relevant spectrum and spatial correlation. The first aerodynamic code developed is based on a one-dimensional turbulent wind model. However, since this model ignores the structure of the turbulence in the crossflow plane, an extension to three dimensions has been made. The computer code developed, CARDAAS, has been used to predict aerodynamic loads for the Sandia-17m rotor and compared to CARDAAV results and experimental data. Results have shown that the computed aerodynamic loads have been improved by including stochastic wind into the aerodynamic model.

  8. Generalization of Naming Responses to Objects in the Natural Environment as a Function of Training Stimulus Modality with Retarded Children.

    ERIC Educational Resources Information Center

    Welch, Steven J.; Pear, Joseph J.

    1980-01-01

    Picture cards, photographs, and real objects were compared as training stimuli in order to determine which best facilitated the generalization of naming responses learned in a special training room to real objects in the natural environments of four severely retarded children (ages 5, 6, 9, and 14). (Author)

  9. Generalization of naming responses to objects in the natural environment as a function of training stimulus modality with retarded children.

    PubMed Central

    Welch, S J; Pear, J J

    1980-01-01

    Picture-cards, photographs, and real objects were compared as training stimuli in order to determine which best facilitated the generalization of naming responses learned in a special training room to real objects in the natural environments of four retarded children. The amount of transfer of naming behavior between the three stimulus modes and the average amount of training time required per stimulus mode were also assessed. Three of the four children displayed considerably more generalization to the real objects in the natural environment when they were trained with real objects. The fourth child displayed substantial generalization regardless of the training stimulus mode. No particular training stimulus mode clearly facilitated the transfer of naming responses to other modes or greatly reduced training time. The results of two supplementary procedures conducted with one child showed that: (1) training in several environments facilitated generalization to real objects in the natural environment when real objects were used as training stimuli but not when picture-cards were used, and (2) transfer from picture-cards to real objects was facilitated by training other picture-cards and the real objects portrayed by them at the same time. PMID:6451607

  10. Aerodynamic characteristics of French consonants

    NASA Astrophysics Data System (ADS)

    Demolin, Didier; Hassid, Sergio; Soquet, Alain

    2001-05-01

    This paper reports some aerodynamic measurements made on French consonants with a group of ten speakers. Speakers were recorded while saying nonsense words in phrases such as papa, dis papa encore. The nonsense words in the study combined each of the French consonants with three vowels /i, a, u/ to from two syllables words with the first syllable being the same as the second. In addition to the audio signal, recordings were made of the oral airflow, the pressure of the air in the pharynx above the vocal folds and the pressure of the air in the trachea just below the vocal folds. The pharyngeal pressure was recorded via a catheter (i.d. 5 mm) passed through the nose so that its open end could be seen in the pharynx below the uvula. The subglottal pressure was recorded via a tracheal puncture between the first and the second rings of the trachea or between the cricoid cartilage and the first tracheal ring. Results compare subglottal presssure, pharyngeal pressure, and airflow values. Comparisons are made between values obtained with male and female subjects and various types of consonants (voiced versus voiceless at the same place of articulation, stops, fricatives, and nasals).

  11. Parachute Aerodynamics From Video Data

    NASA Technical Reports Server (NTRS)

    Schoenenberger, Mark; Queen, Eric M.; Cruz, Juan R.

    2005-01-01

    A new data analysis technique for the identification of static and dynamic aerodynamic stability coefficients from wind tunnel test video data is presented. This new technique was applied to video data obtained during a parachute wind tunnel test program conducted in support of the Mars Exploration Rover Mission. Total angle-of-attack data obtained from video images were used to determine the static pitching moment curve of the parachute. During the original wind tunnel test program the static pitching moment curve had been determined by forcing the parachute to a specific total angle-of -attack and measuring the forces generated. It is shown with the new technique that this parachute, when free to rotate, trims at an angle-of-attack two degrees lower than was measured during the forced-angle tests. An attempt was also made to extract pitch damping information from the video data. Results suggest that the parachute is dynamically unstable at the static trim point and tends to become dynamically stable away from the trim point. These trends are in agreement with limit-cycle-like behavior observed in the video. However, the chaotic motion of the parachute produced results with large uncertainty bands.

  12. Aerodynamics of Unsteady Sailing Kinetics

    NASA Astrophysics Data System (ADS)

    Keil, Colin; Schutt, Riley; Borshoff, Jennifer; Alley, Philip; de Zegher, Maximilien; Williamson, Chk

    2015-11-01

    In small sailboats, the bodyweight of the sailor is proportionately large enough to induce significant unsteady motion of the boat and sail. Sailors use a variety of kinetic techniques to create sail dynamics which can provide an increment in thrust, thereby increasing the boatspeed. In this study, we experimentally investigate the unsteady aerodynamics associated with two techniques, ``upwind leech flicking'' and ``downwind S-turns''. We explore the dynamics of an Olympic class Laser sailboat equipped with a GPS, IMU, wind sensor, and camera array, sailed expertly by a member of the US Olympic team. The velocity heading of a sailing boat is oriented at an apparent wind angle to the flow. In contrast to classic flapping propulsion, the heaving of the sail section is not perpendicular to the sail's motion through the air. This leads to heave with components parallel and perpendicular to the incident flow. The characteristic motion is recreated in a towing tank where the vortex structures generated by a representative 2-D sail section are observed using Particle Image Velocimetry and the measurement of thrust and lift forces. Amongst other results, we show that the increase in driving force, generated due to heave, is larger for greater apparent wind angles.

  13. COMPARISON BETWEEN CONDITIONAL PROBABILITY FUNCTION AND NONPARAMETRIC REGRESSION FOR FINE PARTICLE SOURCE DIRECTIONS. (R831078)

    EPA Science Inventory

    The objective of this study is to examine the use of conditional probability function (CPF) and nonparametric regression (NPR) to identify directions of PM2.5 (particulate matter 2.5 m in aerodynamic diameter) sources using data collected from multiple monitoring sites across ...

  14. Aerodynamics of puffball mushroom spore dispersal

    NASA Astrophysics Data System (ADS)

    Amador, Guillermo; Barberie, Alex; Hu, David

    2012-11-01

    Puffball mushrooms Lycoperdon are spherical fungi that release a cloud of spores in response to raindrop impacts. In this combined experimental and theoretical study, we elucidate the aerodynamics of this unique impact-based spore-dispersal. We characterize live puffball ejections by high speed video, the geometry and elasticity of their shells by cantilever experiments, and the packing fraction and size of their spores by scanning electron microscope. We build a dynamically similar puffball mimic composed of a tied-off latex balloon filled with baby powder and topped with a 1-cm slit. A jet of powder is elicited by steady lateral compression of the mimic between two plates. The jet height is a bell-shaped function of force applied, with a peak of 18 cm at loads of 45 N. We rationalize the increase in jet height with force using Darcy's Law: the applied force generates an overpressure maintained by the air-tight elastic membrane. Pressure is relieved as the air travels through the spore interstitial spaces, entrains spores, and exits through the puffball orifice. This mechanism demonstrates how powder-filled elastic shells can generate high-speed jets using energy harvested from rain.

  15. Ferroelectric Liquid Crystals In Aerodynamic Testing

    NASA Technical Reports Server (NTRS)

    Parmar, Devendra S.; Holmes, Harlan K.

    1994-01-01

    The process of simultaneous optical visualization and quantitative measurement of aerodynamic boundary layer parameters requires new concepts, materials and utilization methods. Measurement of shear stress in terms of the transmitted or the reflected light intensity from an aligned ferroelectric liquid crystal (FLC) thin (approx. 1 micron) film deposited on a glass substrate has been the first step in this direction. In this paper, recent progress in utilization of FLC thin films for skin friction measurement and for studying the state of the boundary layer in a wind tunnel environment is reviewed. The switching characteristics of FLCs have been used to measure pressure from the newly devised system of partially exposed polymer dispersed ferroelectric liquid crystals (PEPDFLCs). In this configuration, a PEPDFLC thin film (approx. 10-25 microns) is sandwiched between two transparent conducting electrodes, one a rigid surface and the other a flexible sheet such as polyvinylidene fluoride or mylar. The switching characteristics of the film are a function of the pressure applied to the flexible transparent electrode and a predetermined bias voltage across the two electrodes. The results, considering the dielectrics of composite media, are discussed.

  16. Unsteady aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Hu, Chien-Chung; Lan, C. E.; Brandon, Jay

    1993-01-01

    Forced oscillation tests over a large angle-of-attack range for an F-18 model are conducted in the NASA Langley 12-foot low-speed tunnel. The resulting dynamic longitudinal data are analyzed with an unsteady aerodynamic modeling method based on Fourier functional analysis and the indicial formulation. The method is extensively examined and improved to automate the calculation of model coefficients, and to evaluate more accurately the indicial integral. The results indicate that the general model equation obtained from harmonic test data in a range of reduced frequency is capable of accurately modeling the nonlinear responses with large hysteresis effect, except in the region where a delayed flow reattachment occurs at low angles of attack in down strokes. The indicial formulation is used to calculate the response to harmonic motion, harmonic ramp motion, constant-rate pitching motion and smaller-amplitude harmonic motion. The results show that more accurate results can be obtained when the motion starts from a low angle of attack where hysteresis effect is not important.

  17. Assessing changes in subjective and objective function from pre- to post-knee arthroplasty using the Cardiff Dempster-Shafer theory classifier.

    PubMed

    Worsley, Peter R; Whatling, Gemma; Barrett, David; Holt, Cathy; Stokes, Maria; Taylor, Mark

    2016-01-01

    The purpose of this study is to assess changes in subjective and objective function from pre- to post-knee arthroplasty (KA) using a combined classifier technique. Twenty healthy adults (50-80 years) and 31 KA patients (39-81 years) were studied (4 weeks pre- and 6 months post-KA). Questionnaire measures of subjective pain, joint stability, activity and function were collected. Objective functional assessment included goniometry, ultrasound imaging and 3-D motion analysis/inverse modelling of gait and sit-stand. An optimal set of variables were used to classify function using the Cardiff Dempster-Shafer theory (DST) method. Out of sample accuracy of the classifiers ranged between 90% and 94% for segregating healthy individuals and pre-KA patients. Post-KA subjective function improved with 74% classified as healthy. However, there was minimal improvement in objective measures (23% classified as healthy). The novel use of Cardiff DST segregated KA patients from healthy individuals and estimated changes in function from pre- to post-surgery. KA patients had improved pain and function post-operation but objective knee joint measures remained different to healthy individuals. PMID:25898862

  18. Application of 3D printing technology in aerodynamic study

    NASA Astrophysics Data System (ADS)

    Olasek, K.; Wiklak, P.

    2014-08-01

    3D printing, as an additive process, offers much more than traditional machining techniques in terms of achievable complexity of a model shape. That fact was a motivation to adapt discussed technology as a method for creating objects purposed for aerodynamic testing. The following paper provides an overview of various 3D printing techniques. Four models of a standard NACA0018 aerofoil were manufactured in different materials and methods: MultiJet Modelling (MJM), Selective Laser Sintering (SLS) and Fused Deposition Modeling (FDM). Various parameters of the models have been included in the analysis: surface roughness, strength, details quality, surface imperfections and irregularities as well as thermal properties.

  19. Nonlinear potential analysis techniques for supersonic-hypersonic aerodynamic design

    NASA Technical Reports Server (NTRS)

    Shankar, V.; Clever, W. C.

    1984-01-01

    Approximate nonlinear inviscid theoretical techniques for predicting aerodynamic characteristics and surface pressures for relatively slender vehicles at supersonic and moderate hypersonic speeds were developed. Emphasis was placed on approaches that would be responsive to conceptual configuration design level of effort. Second order small disturbance and full potential theory was utilized to meet this objective. Numerical codes were developed for relatively general three dimensional geometries to evaluate the capability of the approximate equations of motion considered. Results from the computations indicate good agreement with experimental results for a variety of wing, body, and wing-body shapes.

  20. Quantitative evaluation of manufacturability and performance for ILT produced mask shapes using a single-objective function

    NASA Astrophysics Data System (ADS)

    Choi, Heon; Wang, Wei-long; Kallingal, Chidam

    2015-03-01

    The continuous scaling of semiconductor devices is quickly outpacing the resolution improvements of lithographic exposure tools and processes. This one-sided progression has pushed optical lithography to its limits, resulting in the use of well-known techniques such as Sub-Resolution Assist Features (SRAF's), Source-Mask Optimization (SMO), and double-patterning, to name a few. These techniques, belonging to a larger category of Resolution Enhancement Techniques (RET), have extended the resolution capabilities of optical lithography at the cost of increasing mask complexity, and therefore cost. One such technique, called Inverse Lithography Technique (ILT), has attracted much attention for its ability to produce the best possible theoretical mask design. ILT treats the mask design process as an inverse problem, where the known transformation from mask to wafer is carried out backwards using a rigorous mathematical approach. One practical problem in the application of ILT is the resulting contour-like mask shapes that must be "Manhattanized" (composed of straight edges and 90-deg corners) in order to produce a manufacturable mask. This conversion process inherently degrades the mask quality as it is a departure from the "optimal mask" represented by the continuously curved shapes produced by ILT. However, simpler masks composed of longer straight edges reduce the mask cost as it lowers the shot count and saves mask writing time during mask fabrication, resulting in a conflict between manufacturability and performance for ILT produced masks1,2. In this study, various commonly used metrics will be combined into an objective function to produce a single number to quantitatively measure a particular ILT solution's ability to balance mask manufacturability and RET performance. Several metrics that relate to mask manufacturing costs (i.e. mask vertex count, ILT computation runtime) are appropriately weighted against metrics that represent RET capability (i.e. process

  1. Estimation of the two-dimensional presampled modulation transfer function of digital radiography devices using one-dimensional test objects

    SciTech Connect

    Wells, Jered R.; Dobbins, James T. III

    2012-10-15

    Purpose: The modulation transfer function (MTF) of medical imaging devices is commonly reported in the form of orthogonal one-dimensional (1D) measurements made near the vertical and horizontal axes with a slit or edge test device. A more complete description is found by measuring the two-dimensional (2D) MTF. Some 2D test devices have been proposed, but there are some issues associated with their use: (1) they are not generally available; (2) they may require many images; (3) the results may have diminished accuracy; and (4) their implementation may be particularly cumbersome. This current work proposes the application of commonly available 1D test devices for practical and accurate estimation of the 2D presampled MTF of digital imaging systems. Methods: Theory was developed and applied to ensure adequate fine sampling of the system line spread function for 1D test devices at orientations other than approximately vertical and horizontal. Methods were also derived and tested for slit nonuniformity correction at arbitrary angle. Techniques were validated with experimental measurements at ten angles using an edge test object and three angles using a slit test device on an indirect-detection flat-panel system [GE Revolution XQ/i (GE Healthcare, Waukesha, WI)]. The 2D MTF was estimated through a simple surface fit with interpolation based on Delaunay triangulation of the 1D edge-based MTF measurements. Validation by synthesis was also performed with simulated images from a hypothetical direct-detection flat-panel device. Results: The 2D MTF derived from physical measurements yielded an average relative precision error of 0.26% for frequencies below the cutoff (2.5 mm{sup -1}) and approximate circular symmetry at frequencies below 4 mm{sup -1}. While slit analysis generally agreed with the results of edge analysis, the two showed subtle differences at frequencies above 4 mm{sup -1}. Slit measurement near 45 Degree-Sign revealed radial asymmetry in the MTF resulting from

  2. The influence of the dorsolateral prefrontal cortex on attentional behavior and decision making. A t-DCS study on emotionally vs. functionally designed objects.

    PubMed

    Colombo, Barbara; Balzarotti, Stefania; Mazzucchelli, Nicla

    2016-04-01

    Prior research has shown that right dorsolateral prefrontal cortex may be crucial in cognitive control of affective impulses during decision making. The present study examines whether modulation of r-DLPFC with transcranial direct current stimulation influences attentional behavior and decision-making in a purchase task requiring participants to choose either emotional/attractive or functional/useful objects. 30 participants were shown sixteen pairs of emotionally or functionally designed products while their eye-movements were recorded. Participants were asked to judge aesthetics and usefulness of each object, and to decide which object of each pair they would buy. Results revealed that participants decided to buy the functionally designed objects more often regardless of condition; however, participants receiving anodal stimulation were faster in decision making. Although stimulation of r-DLPFC did not affect the actual purchasing choice and had little effect on visual exploration during decision making, it influenced perceived usefulness and attractiveness, with temporary inhibition of r-DLPFC leading to evaluate functional objects as less attractive. Finally, anodal stimulation led to judge the objects as more useful. The implications of these results are discussed. PMID:26859525

  3. Modeling Powered Aerodynamics for the Orion Launch Abort Vehicle Aerodynamic Database

    NASA Technical Reports Server (NTRS)

    Chan, David T.; Walker, Eric L.; Robinson, Philip E.; Wilson, Thomas M.

    2011-01-01

    Modeling the aerodynamics of the Orion Launch Abort Vehicle (LAV) has presented many technical challenges to the developers of the Orion aerodynamic database. During a launch abort event, the aerodynamic environment around the LAV is very complex as multiple solid rocket plumes interact with each other and the vehicle. It is further complicated by vehicle separation events such as between the LAV and the launch vehicle stack or between the launch abort tower and the crew module. The aerodynamic database for the LAV was developed mainly from wind tunnel tests involving powered jet simulations of the rocket exhaust plumes, supported by computational fluid dynamic simulations. However, limitations in both methods have made it difficult to properly capture the aerodynamics of the LAV in experimental and numerical simulations. These limitations have also influenced decisions regarding the modeling and structure of the aerodynamic database for the LAV and led to compromises and creative solutions. Two database modeling approaches are presented in this paper (incremental aerodynamics and total aerodynamics), with examples showing strengths and weaknesses of each approach. In addition, the unique problems presented to the database developers by the large data space required for modeling a launch abort event illustrate the complexities of working with multi-dimensional data.

  4. Aerodynamic Parameter Identification of a Venus Lander

    NASA Astrophysics Data System (ADS)

    Sykes, Robert A.

    An analysis was conducted to identify the parameters of an aerodynamic model for a Venus lander based on experimental free-flight data. The experimental free-flight data were collected in the NASA Langley 20-ft Vertical Spin Tunnel with a 25-percent Froude-scaled model. The experimental data were classified based on the wind tunnel run type: runs where the lander model was unperturbed over the course of the run, and runs were the model was perturbed (principally in pitch, yaw, and roll) by the wind tunnel operator. The perturbations allow for data to be obtained at higher wind angles and rotation rates than those available from the unperturbed data. The model properties and equations of motion were used to determine experimental values for the aerodynamic coefficients. An aerodynamic model was selected using a priori knowledge of axisymmetric blunt entry vehicles. The least squares method was used to estimate the aerodynamic parameters. Three sets of results were obtained from the following data sets: perturbed, unperturbed, and the combination of both. The combined data set was selected for the final set of aerodynamic parameters based on the quality of the results. The identified aerodynamic parameters are consistent with that of the static wind tunnel data. Reconstructions, of experimental data not used in the parameter identification analyses, achieved similar residuals as those with data used to identify the parameters. Simulations of the experimental data, using the identified parameters, indicate that the aerodynamic model used is incapable of replicating the limit cycle oscillations with stochastic peak amplitudes observed during the test.

  5. The aerodynamics of insect flight.

    PubMed

    Sane, Sanjay P

    2003-12-01

    The flight of insects has fascinated physicists and biologists for more than a century. Yet, until recently, researchers were unable to rigorously quantify the complex wing motions of flapping insects or measure the forces and flows around their wings. However, recent developments in high-speed videography and tools for computational and mechanical modeling have allowed researchers to make rapid progress in advancing our understanding of insect flight. These mechanical and computational fluid dynamic models, combined with modern flow visualization techniques, have revealed that the fluid dynamic phenomena underlying flapping flight are different from those of non-flapping, 2-D wings on which most previous models were based. In particular, even at high angles of attack, a prominent leading edge vortex remains stably attached on the insect wing and does not shed into an unsteady wake, as would be expected from non-flapping 2-D wings. Its presence greatly enhances the forces generated by the wing, thus enabling insects to hover or maneuver. In addition, flight forces are further enhanced by other mechanisms acting during changes in angle of attack, especially at stroke reversal, the mutual interaction of the two wings at dorsal stroke reversal or wing-wake interactions following stroke reversal. This progress has enabled the development of simple analytical and empirical models that allow us to calculate the instantaneous forces on flapping insect wings more accurately than was previously possible. It also promises to foster new and exciting multi-disciplinary collaborations between physicists who seek to explain the phenomenology, biologists who seek to understand its relevance to insect physiology and evolution, and engineers who are inspired to build micro-robotic insects using these principles. This review covers the basic physical principles underlying flapping flight in insects, results of recent experiments concerning the aerodynamics of insect flight, as well

  6. Aerodynamic Characterization of a Thin, High-Performance Airfoil for Use in Ground Fluids Testing

    NASA Technical Reports Server (NTRS)

    Broeren, Andy P.; Lee, Sam; Clark, Catherine

    2013-01-01

    The FAA has worked with Transport Canada and others to develop allowance times for aircraft operating in ice-pellet precipitation. Wind-tunnel testing has been carried out to better understand the flowoff characteristics and resulting aerodynamic effects of anti-icing fluids contaminated with ice pellets using a thin, high-performance wing section at the National Research Council of Canada Propulsion and Icing Wind Tunnel. The objective of this paper is to characterize the aerodynamic behavior of this wing section in order to better understand the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination. Aerodynamic performance data, boundary-layer surveys and flow visualization were conducted at a Reynolds number of approximately 6.0 x 10(exp 6) and a Mach number of 0.12. The clean, baseline model exhibited leading-edge stall characteristics including a leading-edge laminar separation bubble and minimal or no separation on the trailing edge of the main element or flap. These results were consistent with expected 2-D aerodynamics and showed no anomalies that could adversely affect the evaluation of anti-icing fluids and ice-pellet contamination on the wing. Tests conducted with roughness and leading-edge flow disturbances helped to explain the aerodynamic impact of the anti-icing fluids and contamination. The stalling characteristics of the wing section with fluid and contamination appear to be driven at least partially by the effects of a secondary wave of fluid that forms near the leading edge as the wing is rotated in the simulated takeoff profile. These results have provided a much more complete understanding of the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination on this wing section. This is important since these results are used, in part, to develop the ice-pellet allowance times that are applicable to many different airplanes.

  7. Aerodynamic Characterization of a Thin, High-Performance Airfoil for Use in Ground Fluids Testing

    NASA Technical Reports Server (NTRS)

    Broeren, Andy P.; Lee, Sam; Clark, Catherine

    2013-01-01

    The FAA has worked with Transport Canada and others to develop allowance times for aircraft operating in ice-pellet precipitation. Wind-tunnel testing has been carried out to better understand the flowoff characteristics and resulting aerodynamic effects of anti-icing fluids contaminated with ice pellets using a thin, high-performance wing section at the National Research Council of Canada Propulsion and Icing Wind Tunnel. The objective of this paper is to characterize the aerodynamic behavior of this wing section in order to better understand the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination. Aerodynamic performance data, boundary-layer surveys and flow visualization were conducted at a Reynolds number of approximately 6.0×10(exp 6) and a Mach number of 0.12. The clean, baseline model exhibited leading-edge stall characteristics including a leading-edge laminar separation bubble and minimal or no separation on the trailing edge of the main element or flap. These results were consistent with expected 2-D aerodynamics and showed no anomalies that could adversely affect the evaluation of anti-icing fluids and ice-pellet contamination on the wing. Tests conducted with roughness and leading-edge flow disturbances helped to explain the aerodynamic impact of the anti-icing fluids and contamination. The stalling characteristics of the wing section with fluid and contamination appear to be driven at least partially by the effects of a secondary wave of fluid that forms near the leading edge as the wing is rotated in the simulated takeoff profile. These results have provided a much more complete understanding of the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination on this wing section. This is important since these results are used, in part, to develop the ice-pellet allowance times that are applicable to many different airplanes.

  8. Among three different executive functions, general executive control ability is a key predictor of decision making under objective risk

    PubMed Central

    Schiebener, Johannes; Wegmann, Elisa; Gathmann, Bettina; Laier, Christian; Pawlikowski, Mirko; Brand, Matthias

    2014-01-01

    Executive functioning is supposed to have an important role in decision making under risk. Several studies reported that more advantageous decision-making behavior was accompanied by better performance in tests of executive functioning and that the decision-making process was accompanied by activations in prefrontal and subcortical brain regions associated with executive functioning. However, to what extent different components of executive functions contribute to decision making is still unclear. We tested direct and indirect effects of three executive functions on decision-making performance in a laboratory gambling task, the Game of Dice Task (GDT). Using Brand's model of decisions under risk (2006) we tested seven structural equation models with three latent variables that represent executive functions supposed to be involved in decision making. The latent variables were general control (represented by the general ability to exert attentional and behavioral self-control that is in accordance with task goals despite interfering information), concept formation (represented by categorization, rule detection, and set maintenance), and monitoring (represented by supervision of cognition and behavior). The seven models indicated that only the latent dimension general control had a direct effect on decision making under risk. Concept formation and monitoring only contributed in terms of indirect effects, when mediated by general control. Thus, several components of executive functioning seem to be involved in decision making under risk. However, general control functions seem to have a key role. They may be important for implementing the calculative and cognitively controlled processes involved in advantageous decision making under risk. PMID:25520690

  9. NWTS program criteria for mined geologic disposal of nuclear waste: program objectives, functional requirements, and system performance criteria

    SciTech Connect

    1981-04-01

    At the present time, final repository criteria have not been issued by the responsible agencies. This document describes general objectives, requirements, and criteria that the DOE intends to apply in the interim to the National Waste Terminal Storage (NWTS) Program. These objectives, requirements, and criteria have been developed on the basis of DOE's analysis of what is needed to achieve the National objective of safe waste disposal in an environmentally acceptable and economic manner and are expected to be consistent with anticipated regulatory standards. The qualitative statements in this document address the broad issues of public and occupational health and safety, institutional acceptability, engineering feasibility, and economic considerations. A comprehensive set of criteria, general and project specific, of which these are a part, will constitute a portion of the technical basis for preparation and submittal by the DOE of formal documents to support future license applications for nuclear waste repositories.

  10. Missile Aerodynamics for Ascent and Re-entry

    NASA Technical Reports Server (NTRS)

    Watts, Gaines L.; McCarter, James W.

    2012-01-01

    Aerodynamic force and moment equations are developed for 6-DOF missile simulations of both the ascent phase of flight and a tumbling re-entry. The missile coordinate frame (M frame) and a frame parallel to the M frame were used for formulating the aerodynamic equations. The missile configuration chosen as an example is a cylinder with fixed fins and a nose cone. The equations include both the static aerodynamic coefficients and the aerodynamic damping derivatives. The inclusion of aerodynamic damping is essential for simulating a tumbling re-entry. Appended information provides insight into aerodynamic damping.

  11. Fabrication of Functional Nano-objects through RAFT Dispersion Polymerization and Influences of Morphology on Drug Delivery.

    PubMed

    Qiu, Liang; Xu, Chao-Ran; Zhong, Feng; Hong, Chun-Yan; Pan, Cai-Yuan

    2016-07-20

    To study the influence of self-assembled morphologies on drug delivery, four different nano-objects, spheres, nanorods, nanowires, and vesicles having aldehdye-based polymer as core, were successfully prepared via alcoholic RAFT dispersion polymerization of p-(methacryloxyethoxy)benzaldehyde (MAEBA) using poly((N,N'-dimethylamino)ethyl methacrylate) (PDMAEMA) as a macro chain transfer agent (macro-CTA) for the first time. The morphologies and sizes of the four nano-objects were characterized by TEM and DLS, and the spheres with average diameter (D) of 70 nm, the nanorods with D of 19 nm and length of 140 nm, and the vesicles with D of 137 nm were used in the subsequent cellular internalization, in vitro release, and intracellular release of the drug. The anticancer drug doxorubicin (DOX) was conjugated onto the core polymers of nano-objects through condensation reaction between aldehyde groups of the PMAEBA with primary amine groups in the DOX. Because the aromatic imine is stable under neutral conditions, but is decomposed in a weakly acidic solution, in vitro release of the DOX from the DOX-loaded nano-objects was investigated in the different acidic solutions. All of the block copolymer nano-objects show very low cytotoxicity to HeLa cells up to the concentration of 1.2 mg/mL, but the DOX-loaded nano-objects reveal different cell viability and their IC50s increase as the following order: nanorods-DOX < vesicles-DOX < spheres-DOX. The IC50 of nanowires-DOX is the biggest among the four nano-objects owing to their too large size to be internalized. Endocytosis tests demonstrate that the internalization of vesicles-DOX by the HeLa cells is faster than that of the nanorods-DOX, and the spheres-DOX are the slowest to internalize among the studied nano-objects. Relatively more nanorods localized in the acidic organelles of the HeLa cells lead to faster intracellular release of the DOX, so the IC50 of nanorods is lower than that of the vesicles-DOX. PMID:27399846

  12. Aerodynamic Simulation of Ice Accretion on Airfoils

    NASA Technical Reports Server (NTRS)

    Broeren, Andy P.; Addy, Harold E., Jr.; Bragg, Michael B.; Busch, Greg T.; Montreuil, Emmanuel

    2011-01-01

    This report describes recent improvements in aerodynamic scaling and simulation of ice accretion on airfoils. Ice accretions were classified into four types on the basis of aerodynamic effects: roughness, horn, streamwise, and spanwise ridge. The NASA Icing Research Tunnel (IRT) was used to generate ice accretions within these four types using both subscale and full-scale models. Large-scale, pressurized windtunnel testing was performed using a 72-in.- (1.83-m-) chord, NACA 23012 airfoil model with high-fidelity, three-dimensional castings of the IRT ice accretions. Performance data were recorded over Reynolds numbers from 4.5 x 10(exp 6) to 15.9 x 10(exp 6) and Mach numbers from 0.10 to 0.28. Lower fidelity ice-accretion simulation methods were developed and tested on an 18-in.- (0.46-m-) chord NACA 23012 airfoil model in a small-scale wind tunnel at a lower Reynolds number. The aerodynamic accuracy of the lower fidelity, subscale ice simulations was validated against the full-scale results for a factor of 4 reduction in model scale and a factor of 8 reduction in Reynolds number. This research has defined the level of geometric fidelity required for artificial ice shapes to yield aerodynamic performance results to within a known level of uncertainty and has culminated in a proposed methodology for subscale iced-airfoil aerodynamic simulation.

  13. Individual Monitoring of Vocal Effort with Relative Fundamental Frequency: Relationships with Aerodynamics and Listener Perception

    ERIC Educational Resources Information Center

    Lien, Yu-An S.; Michener, Carolyn M.; Eadie, Tanya L.; Stepp, Cara E.

    2015-01-01

    Purpose: The acoustic measure relative fundamental frequency (RFF) was investigated as a potential objective measure to track variations in vocal effort within and across individuals. Method: Twelve speakers with healthy voices created purposeful modulations in their vocal effort during speech tasks. RFF and an aerodynamic measure of vocal effort,…

  14. A study of the nonlinear aerodynamics of bodies in nonplanar motion. Ph.D. Thesis - Stanford Univ., Calif.; [numerical analysis of aerodynamic force and moment systems during large amplitude, arbitrary motions

    NASA Technical Reports Server (NTRS)

    Schiff, L. B.

    1974-01-01

    Concepts from the theory of functionals are used to develop nonlinear formulations of the aerodynamic force and moment systems acting on bodies in large-amplitude, arbitrary motions. The analysis, which proceeds formally once the functional dependence of the aerodynamic reactions upon the motion variables is established, ensures the inclusion, within the resulting formulation, of pertinent aerodynamic terms that normally are excluded in the classical treatment. Applied to the large-amplitude, slowly varying, nonplanar motion of a body, the formulation suggests that the aerodynamic moment can be compounded of the moments acting on the body in four basic motions: steady angle of attack, pitch oscillations, either roll or yaw oscillations, and coning motion. Coning, where the nose of the body describes a circle around the velocity vector, characterizes the nonplanar nature of the general motion.

  15. Prediction of Aerodynamic Coefficients for Wind Tunnel Data using a Genetic Algorithm Optimized Neural Network

    NASA Technical Reports Server (NTRS)

    Rajkumar, T.; Aragon, Cecilia; Bardina, Jorge; Britten, Roy

    2002-01-01

    A fast, reliable way of predicting aerodynamic coefficients is produced using a neural network optimized by a genetic algorithm. Basic aerodynamic coefficients (e.g. lift, drag, pitching moment) are modelled as functions of angle of attack and Mach number. The neural network is first trained on a relatively rich set of data from wind tunnel tests of numerical simulations to learn an overall model. Most of the aerodynamic parameters can be well-fitted using polynomial functions. A new set of data, which can be relatively sparse, is then supplied to the network to produce a new model consistent with the previous model and the new data. Because the new model interpolates realistically between the sparse test data points, it is suitable for use in piloted simulations. The genetic algorithm is used to choose a neural network architecture to give best results, avoiding over-and under-fitting of the test data.

  16. Moisture-dependent frictional and aerodynamic properties of safflower seeds

    NASA Astrophysics Data System (ADS)

    Kara, M.; Bastaban, S.; Öztürk, I.; Kalkan, F.; Yildiz, C.

    2012-04-01

    The seeds of two safflower cultivars were investigated in order to determine their frictional and aerodynamic properties as a function of moisture content. The coefficients of dynamic friction of cultivars on aluminium, plywood, fibreglass and steel surfaces increased by 87, 56, 78, and 129% for cv. Remzibey-05 seed, and by 91, 31, 71, and 131% for cv. Dinçer seed, respectively, between the initial and final moisture content levels. The terminal velocities of the Remzibey-05 and Dinçer seeds increased by 15 and 11%, respectively, with increase in moisture content between the initial and final levels.

  17. Genetic Evolution of Shape-Altering Programs for Supersonic Aerodynamics

    NASA Technical Reports Server (NTRS)

    Kennelly, Robert A., Jr.; Bencze, Daniel P. (Technical Monitor)

    2002-01-01

    Two constrained shape optimization problems relevant to aerodynamics are solved by genetic programming, in which a population of computer programs evolves automatically under pressure of fitness-driven reproduction and genetic crossover. Known optimal solutions are recovered using a small, naive set of elementary operations. Effectiveness is improved through use of automatically defined functions, especially when one of them is capable of a variable number of iterations, even though the test problems lack obvious exploitable regularities. An attempt at evolving new elementary operations was only partially successful.

  18. Aerodynamic Design on Unstructured Grids for Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Anderson, W. Kyle; Bonhaus, Daryl L.

    1997-01-01

    An aerodynamic design algorithm for turbulent flows using unstructured grids is described. The current approach uses adjoint (costate) variables for obtaining derivatives of the cost function. The solution of the adjoint equations is obtained using an implicit formulation in which the turbulence model is fully coupled with the flow equations when solving for the costate variables. The accuracy of the derivatives is demonstrated by comparison with finite-difference gradients and a few example computations are shown. In addition, a user interface is described which significantly reduces the time required for setting up the design problems. Recommendations on directions of further research into the Navier Stokes design process are made.

  19. Depression, Cognition, and Self-Appraisal of Functional Abilities in HIV: An Examination of Subjective Appraisal Versus Objective Performance

    PubMed Central

    Thames, April D.; Becker, Brian W.; Marcotte, Thomas D.; Hines, Lindsay J.; Foley, Jessica M.; Ramezani, Amir; Singer, Elyse J.; Castellon, Steven A.; Heaton, Robert K.; Hinkin, Charles H.

    2013-01-01

    Depression frequently co-occurs with HIV infection and can result in self-reported overestimates of cognitive deficits. Conversely, genuine cognitive dysfunction can lead to an under-appreciation of cognitive deficits. The degree to which depression and cognition influence self-report of capacity for instrumental activities of daily living (IADLs) requires further investigation. This study examined the effects of depression and cognitive deficits on self-appraisal of functional competence among 107 HIV-infected adults. As hypothesized, higher levels of depression were found among those who over-reported problems in medication management, driving, and cognition when compared to those who under-reported or provided accurate self-assessments. In contrast, genuine cognitive dysfunction was predictive of under-reporting of functional deficits. Together, these results suggest that over-reliance on self-reported functional status poses risk for error when diagnoses require documentation of both cognitive impairment and associated functional disability in everyday life. PMID:21331979

  20. Position control optimization of aerodynamic brake device for high-speed trains

    NASA Astrophysics Data System (ADS)

    Zuo, Jianyong; Luo, Zhuojun; Chen, Zhongkai

    2014-03-01

    The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions—constant, linear, and quadratic—are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25.71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

  1. Turbine disk cavity aerodynamics and heat transfer

    NASA Astrophysics Data System (ADS)

    Johnson, B. V.; Daniels, W. A.

    1992-07-01

    Experiments were conducted to define the nature of the aerodynamics and heat transfer for the flow within the disk cavities and blade attachments of a large-scale model, simulating the Space Shuttle Main Engine (SSME) turbopump drive turbines. These experiments of the aerodynamic driving mechanisms explored the following: (1) flow between the main gas path and the disk cavities; (2) coolant flow injected into the disk cavities; (3) coolant density; (4) leakage flows through the seal between blades; and (5) the role that each of these various flows has in determining the adiabatic recovery temperature at all of the critical locations within the cavities. The model and the test apparatus provide close geometrical and aerodynamic simulation of all the two-stage cavity flow regions for the SSME High Pressure Fuel Turbopump and the ability to simulate the sources and sinks for each cavity flow.

  2. Aerodynamics of magnetic levitation (MAGLEV) trains

    NASA Technical Reports Server (NTRS)

    Schetz, Joseph A.; Marchman, James F., III

    1996-01-01

    High-speed (500 kph) trains using magnetic forces for levitation, propulsion and control offer many advantages for the nation and a good opportunity for the aerospace community to apply 'high tech' methods to the domestic sector. One area of many that will need advanced research is the aerodynamics of such MAGLEV (Magnetic Levitation) vehicles. There are important issues with regard to wind tunnel testing and the application of CFD to these devices. This talk will deal with the aerodynamic design of MAGLEV vehicles with emphasis on wind tunnel testing. The moving track facility designed and constructed in the 6 ft. Stability Wind Tunnel at Virginia Tech will be described. Test results for a variety of MAGLEV vehicle configurations will be presented. The last topic to be discussed is a Multi-disciplinary Design approach that is being applied to MAGLEV vehicle configuration design including aerodynamics, structures, manufacturability and life-cycle cost.

  3. Physics of badminton shuttlecocks. Part 1 : aerodynamics

    NASA Astrophysics Data System (ADS)

    Cohen, Caroline; Darbois Texier, Baptiste; Quéré, David; Clanet, Christophe

    2011-11-01

    We study experimentally shuttlecocks dynamics. In this part we show that shuttlecock trajectory is highly different from classical parabola. When one takes into account the aerodynamic drag, the flight of the shuttlecock quickly curves downwards and almost reaches a vertical asymptote. We solve the equation of motion with gravity and drag at high Reynolds number and find an analytical expression of the reach. At high velocity, this reach does not depend on velocity anymore. Even if you develop your muscles you will not manage to launch the shuttlecock very far because of the ``aerodynamic wall.'' As a consequence you can predict the length of the field. We then discuss the extend of the aerodynamic wall to other projectiles like sports balls and its importance.

  4. Miniature Trailing Edge Effector for Aerodynamic Control

    NASA Technical Reports Server (NTRS)

    Lee, Hak-Tae (Inventor); Bieniawski, Stefan R. (Inventor); Kroo, Ilan M. (Inventor)

    2008-01-01

    Improved miniature trailing edge effectors for aerodynamic control are provided. Three types of devices having aerodynamic housings integrated to the trailing edge of an aerodynamic shape are presented, which vary in details of how the control surface can move. A bucket type device has a control surface which is the back part of a C-shaped member having two arms connected by the back section. The C-shaped section is attached to a housing at the ends of the arms, and is rotatable about an axis parallel to the wing trailing edge to provide up, down and neutral states. A flip-up type device has a control surface which rotates about an axis parallel to the wing trailing edge to provide up, down, neutral and brake states. A rotating type device has a control surface which rotates about an axis parallel to the chord line to provide up, down and neutral states.

  5. Aerodynamic tests of Darrieus wind turbine blades

    SciTech Connect

    Migliore, P.G.; Walters, R.E.; Wolfe, W.P.

    1983-03-01

    An indoor facility for the aerodynamic testing of Darrieus turbine blades was developed. Lift, drag, and moment coefficients were measured for two blades whose angle of attack and chord-to-radius ratio were varied. The first blade used an NACA 0015 airfoil section; the second used a 15% elliptical cross section with a modified circular arc trailing edge. Blade aerodynamic coefficients were corrected to section coefficients for comparison to published rectilinear flow data. Although the airfoil sections were symmetrical, moment coefficients were not zero and the lift and drag curves were asymmetrical about zero lift coefficient and angle of attack. These features verified the predicted virtual camber and incidence phenomena. Boundary-layer centrifugal effects were manifested by discontinuous lift curves and large differences in the angle of zero lift between th NACA 0015 and elliptical airfoils. It was concluded that rectilinear flow aerodynamic data are not applicable to Darrieus turbine blades, even for small chord-to-radius ratios.

  6. History of the numerical aerodynamic simulation program

    NASA Technical Reports Server (NTRS)

    Peterson, Victor L.; Ballhaus, William F., Jr.

    1987-01-01

    The Numerical Aerodynamic Simulation (NAS) program has reached a milestone with the completion of the initial operating configuration of the NAS Processing System Network. This achievement is the first major milestone in the continuing effort to provide a state-of-the-art supercomputer facility for the national aerospace community and to serve as a pathfinder for the development and use of future supercomputer systems. The underlying factors that motivated the initiation of the program are first identified and then discussed. These include the emergence and evolution of computational aerodynamics as a powerful new capability in aerodynamics research and development, the computer power required for advances in the discipline, the complementary nature of computation and wind tunnel testing, and the need for the government to play a pathfinding role in the development and use of large-scale scientific computing systems. Finally, the history of the NAS program is traced from its inception in 1975 to the present time.

  7. Wind turbine aerodynamics research needs assessment

    NASA Astrophysics Data System (ADS)

    Stoddard, F. S.; Porter, B. K.

    1986-01-01

    A prioritized list is developed for wind turbine aerodynamic research needs and opportunities which could be used by the Department of Energy program management team in detailing the DOE Five-Year Wind Turbine Research Plan. The focus of the Assessment was the basic science of aerodynamics as applied to wind turbines, including all relevant phenomena, such as turbulence, dynamic stall, three-dimensional effects, viscosity, wake geometry, and others which influence aerodynamic understanding and design. The study was restricted to wind turbines that provide electrical energy compatible with the utility grid, and included both horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). Also, no economic constraints were imposed on the design concepts or recommendations since the focus of the investigation was purely scientific.

  8. Aerodynamic optimization studies on advanced architecture computers

    NASA Technical Reports Server (NTRS)

    Chawla, Kalpana

    1995-01-01

    The approach to carrying out multi-discipline aerospace design studies in the future, especially in massively parallel computing environments, comprises of choosing (1) suitable solvers to compute solutions to equations characterizing a discipline, and (2) efficient optimization methods. In addition, for aerodynamic optimization problems, (3) smart methodologies must be selected to modify the surface shape. In this research effort, a 'direct' optimization method is implemented on the Cray C-90 to improve aerodynamic design. It is coupled with an existing implicit Navier-Stokes solver, OVERFLOW, to compute flow solutions. The optimization method is chosen such that it can accomodate multi-discipline optimization in future computations. In the work , however, only single discipline aerodynamic optimization will be included.

  9. Aerodynamic Models for the Low Density Supersonic Decelerator (LDSD) Test Vehicles

    NASA Technical Reports Server (NTRS)

    Van Norman, John W.; Dyakonov, Artem; Schoenenberger, Mark; Davis, Jody; Muppidi, Suman; Tang, Chun; Bose, Deepak; Mobley, Brandon; Clark, Ian

    2016-01-01

    An overview of aerodynamic models for the Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) campaign test vehicle is presented, with comparisons to reconstructed flight data and discussion of model updates. The SFDT campaign objective is to test Supersonic Inflatable Aerodynamic Decelerator (SIAD) and large supersonic parachute technologies at high altitude Earth conditions relevant to entry, descent, and landing (EDL) at Mars. Nominal SIAD test conditions are attained by lifting a test vehicle (TV) to 36 km altitude with a helium balloon, then accelerating the TV to Mach 4 and 53 km altitude with a solid rocket motor. Test flights conducted in June of 2014 (SFDT-1) and 2015 (SFDT-2) each successfully delivered a 6 meter diameter decelerator (SIAD-R) to test conditions and several seconds of flight, and were successful in demonstrating the SFDT flight system concept and SIAD-R technology. Aerodynamic models and uncertainties developed for the SFDT campaign are presented, including the methods used to generate them and their implementation within an aerodynamic database (ADB) routine for flight simulations. Pre- and post-flight aerodynamic models are compared against reconstructed flight data and model changes based upon knowledge gained from the flights are discussed. The pre-flight powered phase model is shown to have a significant contribution to off-nominal SFDT trajectory lofting, while coast and SIAD phase models behaved much as predicted.

  10. The DaveMLTranslator: An Interface for DAVE-ML Aerodynamic Models

    NASA Technical Reports Server (NTRS)

    Hill, Melissa A.; Jackson, E. Bruce

    2007-01-01

    It can take weeks or months to incorporate a new aerodynamic model into a vehicle simulation and validate the performance of the model. The Dynamic Aerospace Vehicle Exchange Markup Language (DAVE-ML) has been proposed as a means to reduce the time required to accomplish this task by defining a standard format for typical components of a flight dynamic model. The purpose of this paper is to describe an object-oriented C++ implementation of a class that interfaces a vehicle subsystem model specified in DAVE-ML and a vehicle simulation. Using the DaveMLTranslator class, aerodynamic or other subsystem models can be automatically imported and verified at run-time, significantly reducing the elapsed time between receipt of a DAVE-ML model and its integration into a simulation environment. The translator performs variable initializations, data table lookups, and mathematical calculations for the aerodynamic build-up, and executes any embedded static check-cases for verification. The implementation is efficient, enabling real-time execution. Simple interface code for the model inputs and outputs is the only requirement to integrate the DaveMLTranslator as a vehicle aerodynamic model. The translator makes use of existing table-lookup utilities from the Langley Standard Real-Time Simulation in C++ (LaSRS++). The design and operation of the translator class is described and comparisons with existing, conventional, C++ aerodynamic models of the same vehicle are given.

  11. Exploration of the Rapid Effects of Personal Fine Particulate Matter Exposure on Hemodynamics and Vascular Function during the Same Day

    EPA Science Inventory

    Background: Levels of fine particulate matter [≤ 2.5 μm in aerodynamic diameter (PM2.5)] are associated with alterations in arterial hemodynamics and vascular function. However, the characteristics of the same-day exposure–response relationships remain unclear. Object...

  12. Aerodynamic interactions between a 1/6 scale helicopter rotor and a body of revolution

    NASA Technical Reports Server (NTRS)

    Betzina, M. D.; Shinoda, P.

    1982-01-01

    A wind-tunnel investigation was conducted in which independent, steady state aerodynamic forces and moments were measured on a 2.24-m-diam, two bladed helicopter rotor and a body of revolution. The objective was to determine the interaction of the body on the rotor performance and the effect of the rotor on the body aerodynamics for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body nose geometry. Results show that a body of revolution near the rotor can produce significant favorable or unfavorable effects on rotor performance, depending on the operating condition. Body longitudinal aerodynamic characteristics are significantly modified by the presence of an operating rotor and hub.

  13. The association between cognitive function and objective adherence to dietary sodium guidelines in patients with heart failure

    PubMed Central

    Dolansky, Mary A; Schaefer, Julie T; Hawkins, Misty AW; Gunstad, John; Basuray, Anup; Redle, Joseph D; Fang, James C; Josephson, Richard A; Moore, Shirley M; Hughes, Joel W

    2016-01-01

    Background Although cognitive impairment is common in heart failure (HF) patients, its effects on sodium adherence recommendations are unknown. Purpose Our aim is to examine if cognitive function is associated with patient sodium adherence. Methods Sodium collection/excretion and cognitive function were assessed for 339 HF patients over a 5–8-week period. Neuropsychological testing was performed at baseline (Visit 1), whereas two 24-hour urine samples were collected within 7 weeks postbaseline. The ability to collect two 24-hour urine samples and the estimation of sodium excretion levels from these samples were used to estimate sodium adherence recommendations. Results Nearly half (47%) of the study participants (n=159) were unable to give two valid 24-hour urine samples. Participants who were unable to adhere to two valid 24-hour urine samples had significantly poorer attention and global cognition tests (P<0.044), with a trend for poorer executive function (P=0.064). Among those with valid samples, urine sodium level was not associated with global cognitive function, attention, executive function, or memory after adjusting for covariates. Female sex was associated with lower sodium excretion (all P<0.01); individuals with knowledge of sodium guidelines had less intake of sodium, resulting in excretion of less sodium (all P≤0.03). Conversely, higher socioeconomic status (SES) and body mass index (BMI) were associated with greater sodium (all P≤0.02 and P≤0.01). Conclusion Adherence to urine sodium collection was poor, especially among those with poorer cognitive function. Sodium consumption exceeded recommended amounts and was unrelated to cognitive function. Interventions for improving sodium adherence should focus on at-risk groups (high SES and BMI) and at improving knowledge of recommended salt intake. PMID:27042017

  14. A new method to calibrate aerodynamic roughness over the Tibetan Plateau using Ensemble Kalman Filter

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Timmermans, J.; Su, Z.; Mancini, M.

    2012-04-01

    Aerodynamic roughness height (Zom) is a key parameter required in land surface hydrological model, since errors in heat flux estimations are largely dependent on accurate optimization of this parameter. Despite its significance, it remains an uncertain parameter that is not easily determined. This is mostly because of non-linear relationship in Monin-Obukhov Similarity (MOS) and unknown vertical characteristic of vegetation. Previous studies determined aerodynamic roughness using traditional wind profile method, remotely sensed vegetation index, minimization of cost function over MOS relationship or linear regression. However, these are complicated procedures that presume high accuracy for several other related parameters embedded in MOS equations. In order to simplify a procedure and reduce the number of parameters in need, this study suggests a new approach to extract aerodynamic roughness parameter via Ensemble Kalman Filter (EnKF) that affords non-linearity and that requires only single or two heat flux measurement. So far, to our knowledge, no previous study has applied EnKF to aerodynamic roughness estimation, while a majority of data assimilation study has paid attention to land surface state variables such as soil moisture or land surface temperature. This approach was applied to grassland in semi-arid Tibetan area and maize on moderately wet condition in Italy. It was demonstrated that aerodynamic roughness parameter can inversely be tracked from data assimilated heat flux analysis. The aerodynamic roughness height estimated in this approach was consistent with eddy covariance result and literature value. Consequently, this newly estimated input adjusted the sensible heat overestimated and latent heat flux underestimated by the original Surface Energy Balance System (SEBS) model, suggesting better heat flux estimation especially during the summer Monsoon period. The advantage of this approach over other methodologies is that aerodynamic roughness height

  15. Function of opioidergic and dopaminergic antagonists on both spatial and object novelty detection deficits induced in rodent model of hepatic encephalopathy.

    PubMed

    Nasehi, Mohammad; Mafi, Fatemeh; Ebrahimi-Ghiri, Mohaddeseh; Zarrindast, Mohammad-Reza

    2016-10-15

    Liver disease has been known for a long time to affect brain function. We now report the function of opioidergic and dopaminergic antagonists on both spatial and object novelty detection deficits induced by hepatic encephalopathy (HE) following bile duct ligation (BDL), a model of chronic liver disease. Assessment of spatial and object novelty detection memories was carried out in the non-associative task. It consists of placing mice in an open field containing five objects and, after three sessions of habituation, examining their reactivity to object displacement (spatial novelty) and object substitution (object novelty). Both spatial and object novelty detection memories were impaired by BDL after 4 weeks. In the BDL mice, pre-test intraperitoneal administration of naloxone (μ-opioidergic receptor antagonist) at dose of 0.9mg/kg restored while sulpiride (D2-like dopamine receptor antagonist) at dose of 40mg/kg potentiated object novelty detection memory deficit. However, SCH23390 (D1-like dopamine receptor antagonist) at dose of 0.04mg/kg or sulpiride (20mg/kg) restored spatial novelty detection memory deficit. Moreover, SCH23390 or sulpiride impaired while naloxone did not alter both memories in sham-operated mice. Furthermore, subthreshold dose co-administration of dopaminergic antagonists together or each one plus naloxone did not alter both memory impairments in BDL mice, while all of three co-administration groups impaired object novelty detection and co-administration of naloxone plus sulpiride impaired spatial detection memory in sham-operated mice. In conclusion, we suggest that opioidergic and dopaminergic systems through separate pathways may contribute in memory impairments induced by BDL in the non-associative task. PMID:27401106

  16. Airfoil Ice-Accretion Aerodynamics Simulation

    NASA Technical Reports Server (NTRS)

    Bragg, Michael B.; Broeren, Andy P.; Addy, Harold E.; Potapczuk, Mark G.; Guffond, Didier; Montreuil, E.

    2007-01-01

    NASA Glenn Research Center, ONERA, and the University of Illinois are conducting a major research program whose goal is to improve our understanding of the aerodynamic scaling of ice accretions on airfoils. The program when it is completed will result in validated scaled simulation methods that produce the essential aerodynamic features of the full-scale iced-airfoil. This research will provide some of the first, high-fidelity, full-scale, iced-airfoil aerodynamic data. An initial study classified ice accretions based on their aerodynamics into four types: roughness, streamwise ice, horn ice, and spanwise-ridge ice. Subscale testing using a NACA 23012 airfoil was performed in the NASA IRT and University of Illinois wind tunnel to better understand the aerodynamics of these ice types and to test various levels of ice simulation fidelity. These studies are briefly reviewed here and have been presented in more detail in other papers. Based on these results, full-scale testing at the ONERA F1 tunnel using cast ice shapes obtained from molds taken in the IRT will provide full-scale iced airfoil data from full-scale ice accretions. Using these data as a baseline, the final step is to validate the simulation methods in scale in the Illinois wind tunnel. Computational ice accretion methods including LEWICE and ONICE have been used to guide the experiments and are briefly described and results shown. When full-scale and simulation aerodynamic results are available, these data will be used to further develop computational tools. Thus the purpose of the paper is to present an overview of the program and key results to date.

  17. 3-Year-Old Children Selectively Generalize Object Functions Following a Demonstration from a Linguistic In-group Member: Evidence from the Phenomenon of Scale Error.

    PubMed

    Oláh, Katalin; Elekes, Fruzsina; Pető, Réka; Peres, Krisztina; Király, Ildikó

    2016-01-01

    The present study investigated 3-year-old children's learning processes about object functions. We built on children's tendency to commit scale errors with tools to explore whether they would selectively endorse object functions from a linguistic in-group over an out-group model. Participants (n = 37) were presented with different object sets, and a model speaking either in their native or a foreign language demonstrated how to use the presented tools. In the test phase, children received the object sets with two modifications: the original tool was replaced by one that was too big to achieve the goal but was otherwise identical, and another tool was added to the set that looked different but was appropriately scaled for goal attainment. Children in the Native language condition were significantly more likely to commit scale errors - that is, choose the over-sized tool - than children in the Foreign language condition (48 vs. 30%). We propose that these results provide insight into the characteristics of human-specific learning processes by showing that children are more likely to generalize object functions to a category of artifacts following a demonstration from an in-group member. PMID:27445925

  18. 3-Year-Old Children Selectively Generalize Object Functions Following a Demonstration from a Linguistic In-group Member: Evidence from the Phenomenon of Scale Error

    PubMed Central

    Oláh, Katalin; Elekes, Fruzsina; Pető, Réka; Peres, Krisztina; Király, Ildikó

    2016-01-01

    The present study investigated 3-year-old children’s learning processes about object functions. We built on children’s tendency to commit scale errors with tools to explore whether they would selectively endorse object functions from a linguistic in-group over an out-group model. Participants (n = 37) were presented with different object sets, and a model speaking either in their native or a foreign language demonstrated how to use the presented tools. In the test phase, children received the object sets with two modifications: the original tool was replaced by one that was too big to achieve the goal but was otherwise identical, and another tool was added to the set that looked different but was appropriately scaled for goal attainment. Children in the Native language condition were significantly more likely to commit scale errors – that is, choose the over-sized tool – than children in the Foreign language condition (48 vs. 30%). We propose that these results provide insight into the characteristics of human-specific learning processes by showing that children are more likely to generalize object functions to a category of artifacts following a demonstration from an in-group member. PMID:27445925

  19. Method of reducing drag in aerodynamic systems

    NASA Technical Reports Server (NTRS)

    Hrach, Frank J. (Inventor)

    1993-01-01

    In the present method, boundary layer thickening is combined with laminar flow control to reduce drag. An aerodynamic body is accelerated enabling a ram turbine on the body to receive air at velocity V sub 0. The discharge air is directed over an aft portion of the aerodynamic body producing boundary layer thickening. The ram turbine also drives a compressor by applying torque to a shaft connected between the ram turbine and the compressor. The compressor sucks in lower boundary layer air through inlets in the shell of the aircraft producing laminar flow control and reducing drag. The discharge from the compressor is expanded in a nozzle to produce thrust.

  20. Air flow testing on aerodynamic truck

    NASA Technical Reports Server (NTRS)

    1975-01-01

    After leasing a cab-over tractor-trailer from a Southern California firm, Dryden researchers added sheet metal modifications like those shown here. They rounded the front corners and edges, and placed a smooth fairing on the cab's roofs and sides extending back to the trailer. During the investigation of truck aerodynamics, the techniques honed in flight research proved highly applicable. By closing the gap between the cab and the trailer, for example, researchers discovered a significant reduction in aerodynamic drag, one resulting in 20 to 25 percent less fuel consumption than the standard design. Many truck manufacturers subsequently incorporated similar modifications on their products.